COMSAT CORP
10-K, 1999-03-25
COMMUNICATIONS SERVICES, NEC
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<PAGE>
 
                      SECURITIES AND EXCHANGE COMMISSION
                            Washington, D.C. 20549


                                   FORM 10-K


               Annual Report Pursuant to Section 13 or 15(d) of
                      the Securities Exchange Act of 1934

     For the fiscal year                                    Commission file 
    ended December 31, 1998                                  number 1-4929

                              COMSAT Corporation
            (Exact name of registrant as specified in its charter)

        
        District of Columbia                                   52-0781863
  (State or other jurisdiction of                           (I.R.S. Employer
   incorporation or organization)                          Identification No.)


                  6560 Rock Spring Drive, Bethesda, MD  20817
                   (Address of principal executive offices)

Registrant's telephone number, including area code:(301) 214-3000

Securities registered pursuant to Section 12(b) of the Act:

                                                    Name of each exchange 
     Title of each class                            on which registered
     -------------------                            ---------------------
     Common Stock, without par value                New York Stock Exchange
                                                    Chicago Stock Exchange
                                                    Pacific Stock Exchange

     8 1/8% Cumulative Monthly Income               New York Stock Exchange
     Preferred Securities of
     COMSAT Capital I, L.P.

Securities registered pursuant to Section 12(g) of the Act:  None.

     Indicate by check mark whether the Registrant (1) has filed all reports
required to be filed by Section 13  or 15(d) of the Securities Exchange Act of
1934 during the preceding 12 months (or for such shorter period that the
Registrant  was required to file such reports), and (2) has been subject to such
filing requirements for the past 90 days.     Yes    X           No
                                                 -----------       -----------

     Indicate by check mark if disclosure of delinquent filers pursuant to Item
405 of Regulation S-K is not contained herein, and will not be contained, to the
best of Registrant's knowledge, any amendment to this Form 10-K. [  ]

     Aggregate market value of voting stock held by non-affiliates of the
Registrant was $1,497,888,670  based on a closing market price of $29.75 per
share on March 1, 1999, as reported on the composite tape for New York Stock
Exchange listed issues.

     52,617,999 shares of common stock, without par value, were outstanding on
March 1, 1999.

                      DOCUMENTS INCORPORATED BY REFERENCE

     The following documents are incorporated by reference: NONE.
<PAGE>
 
                                     PART I

Item 1:   Business

                              GENERAL INFORMATION

Business Segments

     COMSAT Corporation (COMSAT, the Corporation or Registrant) reports
operating results and financial data in four business segments: COMSAT World
Systems (CWS), COMSAT Mobile Communications (CMC), COMSAT International (CI) and
COMSAT Laboratories (Labs).

     .    CWS provides satellite capacity for telephone, data, Internet, video
          and audio communications services between the U.S. and the rest of the
          world using the global satellite networks of the International
          Telecommunications Satellite Organization (INTELSAT) and New Skies
          Satellites, N.V. (New Skies).  The CWS segment also includes COMSAT
          General Corporation (COMSAT General), COMSAT Digital Teleport, Inc.
          (CDTI) and COMSAT Government Systems, Inc. (CGSI), which provide
          various satellite and ground segment services to commercial and
          government customers.

     .    CMC provides satellite telecommunications services for maritime,
          aeronautical and land mobile applications primarily using the
          satellite system of the International Mobile Satellite Organization
          (Inmarsat).

     .    CI operates an integrated group of telecommunications companies that
          principally provide individualized digital network solutions and value
          added services to business clients and carriers in selected emerging
          markets.

     .    Labs provides technical consulting services and develops advanced
          communications technologies and products for satellite access and
          networking applications.

     Financial information by business segment for each of the last three years
is set forth in Note 16 to the financial statements.

     The Corporation adopted Statement of Financial Accounting Standards (SFAS)
No. 131, "Disclosures About Segments of an Enterprise and Related Information,"
in 1998 which changes the way the Corporation reports information about its
operating segments.  Prior to the fourth quarter of 1998, the Corporation
reported operating results and financial data in two business segments:
Satellite Services (consisting of CWS and CMC) and Network Services (consisting
of CI, Labs and Government Programs).  The Corporation began accounting for
substantially all of its former entertainment and manufacturing businesses as
discontinued operations in the second quarter of 1997.  For information
concerning the Corporation's discontinued operations, see "Business -
Discontinued Operations" and Note 3 to the financial statements.

                                       2
<PAGE>
 
     The Corporation had approximately 1,600 employees as of  December 31, 1998.
The only employees represented by a labor union are the approximately 126
employees working on the construction of the radio astronomy telescope project
in Green Bank, West Virginia.

Communications Satellite Act of 1962

     COMSAT was incorporated in 1963 under District of Columbia law, as
authorized by the Communications Satellite Act of 1962 (the Satellite Act).  In
1993, COMSAT changed its corporate name from "Communications Satellite
Corporation" to "COMSAT Corporation."  COMSAT is not an agency or establishment
of the United States Government.  The U.S. Government has not invested funds in
COMSAT, guaranteed funds invested in COMSAT or guaranteed the payment of
dividends by COMSAT.  The U.S. Government has no ownership interest in COMSAT.

     Although COMSAT is a private corporation, the Satellite Act regulates
certain aspects of COMSAT's structure, ownership and operations, including:

     .    three of COMSAT's 15 director positions are appointed by the
          President of the United States with the advice and consent of the
          United States Senate (one of those positions is currently vacant);

     .    COMSAT's issuance of capital stock and borrowing of money must be
          authorized by the Federal Communications Commission (FCC);

     .    there are limitations on the classes of persons that may hold shares
          of COMSAT's common stock and on the percentage of outstanding shares a
          person or class of persons may hold; and

     .    on matters that may affect the national interest and foreign policy
          of the United States, COMSAT's representatives to INTELSAT and
          Inmarsat receive instructions from the U.S. Government.

     Congress has reserved the right to amend the Satellite Act, and amendments,
if any, could materially affect the Corporation.  Legislation is currently
pending in Congress to overhaul the Satellite Act.  See "Item 7: Management's
Discussion and Analysis of Financial Condition and Results of Operations -
Outlook - Regulatory and Legislative Developments."

Government Regulation

     Under the Satellite Act, the International Maritime Satellite
Telecommunications Act of 1978 (the Inmarsat Act) and the Communications Act of
1934, as amended (the Communications Act), COMSAT is subject to regulation by
the FCC with respect to its capital and organizational structure, as well as
CWS's and CMC's plant, operations, services and rates.  In addition, COMSAT
General and CGSI are common carriers regulated by the FCC.  FCC decisions and
policies have had and will continue to have a significant impact on the
Corporation.  Specific aspects of the regulation of CWS and CMC are discussed in
the narratives concerning those segments.  See "Business - COMSAT World Systems

                                       3
<PAGE>
 
- - Regulation of CWS" and "Business - COMSAT Mobile Communications - Regulation
of CMC." Certain parts of COMSAT's business are also regulated by foreign
governments.

                              COMSAT World Systems

Services

     CWS provides satellite capacity for telephone, data, Internet, video and
audio communications services between the United States and the rest of the
world using the global satellite networks of INTELSAT and New Skies.  CWS's
customers include U.S. international communications common carriers, teleports,
private network providers, multinational corporations, U.S. and international
broadcasters, news-gathering organizations, digital audio companies and the U.S.
government.

     The largest portion of CWS's revenues comes from providing full-time voice-
grade half-circuits (two-way communications links between an earth station and
an INTELSAT satellite) to U.S. international communications common carriers.
The three largest carrier customers are AT&T Corporation (AT&T), MCI WorldCom,
Inc. (MCI WorldCom) and Sprint Corporation (Sprint).  CWS offers significant
discounts to customers entering into long-term commitments for full-time voice-
grade half-circuits.  Approximately 95% of all eligible voice-grade half-
circuits are now under such commitments.

     At year end 1998, approximately 81% of CWS's International Digital Route
(IDR) and International Business Service (IBS) traffic was under long-term
commitments with INTELSAT.  CWS has short-term commitments with INTELSAT for the
remaining portion of its IDR and IBS traffic.  CWS also enters into commitments
with INTELSAT for video traffic, which vary in length depending on the length of
commitments from CWS's customers.

     CWS's voice and data services are virtually all digital.  CWS's IDR
service, for example, makes it possible for communications carriers to provide
digital public-switched telephone network circuits.  The carriers apply
techniques to such circuits that permit a single digital circuit to handle
multiple telephone calls simultaneously.

     For private-line customers, CWS offers an all-digital IBS, as well as an
international VSAT (very small aperture terminal) service.  IBS offers customers
high-speed, digital communications for voice, data, facsimile and video
conferencing using on-premise earth stations that eliminate the need for costly
land-line connections.  At year end 1998, approximately 97% of CWS's IBS traffic
was covered by long-term commitments.  CWS's customers have established
international VSAT networks in both Latin America and Europe.  Using on-premise
antennas as small as 1.8 meters in combination with the high-power satellites in
the INTELSAT network, corporations doing business internationally can deliver
communications to multiple sites.  Used primarily for data transmissions, VSATs
can also accommodate voice and video communications. CWS's carrier and Internet
Service Provider customers frequently employ either IBS or international VSAT
services to implement their Internet applications.  These services are well-
suited for either high speed point-to-point or point-to-multipoint Internet
applications. In addition to providing reliable worldwide access to the
Internet, IBS and VSAT services offer features to customers, such as simplified
network architectures, asymmetric data rates, and quick turnup of satellite

                                       4
<PAGE>
 
connectivity.  The global demand for Internet access has been growing at a high
rate.  The applicability of IBS and VSAT for the support of Internet
applications is the main growth driver for these services.

     To the growing international broadcasting community, CWS provides both
digital and analog transmission services on a long-term, short-term or
occasional as-needed basis.  With the introduction of the INTELSAT VII, VIIA and
VIII satellites, CWS has expanded the availability of high-power, flexible
capacity for broadcasters and satellite news gatherers.  See "Item 2: Properties
- - INTELSAT Satellites."

     To maintain the quality of the INTELSAT network, CWS provides tracking,
telemetry, control (TT&C) and monitoring services to INTELSAT and engages in a
program of research and development to ensure that the satellite system
accommodates the latest communications technologies, including broadband,
integrated services digital networks (ISDN), and asynchronous transfer mode
(ATM).

     The CWS business also includes the operations of COMSAT General, CDTI and
CGSI, all of which are wholly-owned subsidiaries of the Corporation.

     COMSAT General provides a line of satellite-based communications services
to provide business data solutions.  This includes satellite circuits, ground
station transit services, connecting terrestrial links, baseband network
terminal equipment and engineering services for international host nation
licensing and approvals.  COMSAT General provides services to commercial,
government and international organizations, and is an FCC-licensed common
carrier.  COMSAT General also operates via the INTELSAT system from certain
foreign countries.

     COMSAT General operates satellite earth station facilities located in
Clarksburg, Maryland, Santa Paula, California, and Southbury, Connecticut.
COMSAT General also operates a satellite control facility and high speed fiber
interconnects to telecommunications carriers and Internet service providers.
COMSAT General provides its customers with satellite services over a variety of
international and domestic satellite systems, including INTELSAT and Inmarsat,
for voice, data, Internet and one-way video broadcast.

     COMSAT General provides satellite operation service for the MARISAT and
COMSTAR satellites, which includes tracking, telemetry, command and orbital
maintenance for these spacecraft.  In addition to operating the satellites,
COMSAT General also provides transponder capacity on such satellites.

     CDTI provides turnkey satellite services through facilities located in
Clarksburg, Maryland and Santa Paula, California.  CDTI network services include
satellite and terrestrial segments, network management, and installation and
maintenance of required hardware.  CDTI also offers bundled satellite service
including space and ground segment for Internet, video, and digital data
applications.

     CGSI is a wholly-owned subsidiary established primarily to support the
Commercial Satellite Communications Initiative (CSCI) program.  CGSI has a
contract with the Defense Information Systems Agency (DISA) to provide bulk
commercial satellite transponder leases.  CGSI also operates two bandwidth
management centers.

                                       5
<PAGE>
 
Revenues

     Approximately 49% of the Corporation's consolidated revenues in 1998 were
derived from CWS services (compared to 51% in 1997 and 55% in 1996).
Approximately 9% of the Corporation's consolidated revenues in 1998 were derived
from CWS services to AT&T.  Also in 1998, CWS's three largest customers, AT&T,
MCI WorldCom and Sprint, were the source of approximately 19%, 18% and 7%,
respectively, of CWS's revenues.  See Note 16 to the financial statements.

INTELSAT

     INTELSAT is a 143-member international organization headquartered in
Washington, D.C.  It operates under three agreements: an intergovernmental
agreement; a headquarters agreement with the U.S. Government; and an operating
agreement signed by each member nation's government or designated
telecommunications entity (a Signatory).
 
     COMSAT is the U.S. Signatory.  It represents the U.S. in INTELSAT, subject
to instructions from the Department of State (in concert with the Department of
Commerce and the FCC) on matters that may affect U.S. national interest and
foreign policy.

     Each shareholder has rights and obligations in INTELSAT analogous to those
of a partner.  Each owns an investment share, makes proportionate contributions
to INTELSAT's capital costs, and receives proportionate distributions of
INTELSAT's net revenues after deductions for operating expenses. Shareholders
also pay INTELSAT for their use of the satellite system.   The investment shares
are readjusted in March  each year to approximate the shareholders' respective
portions of the total use of the INTELSAT space segment for the previous six
months.  CWS's investment share, the largest in INTELSAT, was approximately
18.0% as of December 31, 1998, which was unchanged from December 31, 1997.
Effective March 1, 1999, CWS's investment share in INTELSAT increased to
approximately 19.8%.  At December 31, 1998, total INTELSAT owners' equity was
approximately $1.63 billion.  The rate of return on shareholders' capital is
subject to change based on business conditions.  INTELSAT does not guarantee a
return to Signatories.

     Since 1995 INTELSAT has allowed non-Signatory telecommunications entities
to participate as shareholders in the organization. As of December 31, 1998,
there were 48 non-Signatory shareholders accounting for total shares of 6.6%.
As of December 31, 1998, COMSAT Argentina and COMSAT General together owned
approximately 0.4% of INTELSAT.

     INTELSAT generally procures spacecraft and launch services under long-term,
multi-satellite contracts which provide for payments by INTELSAT over the
contract periods.  Under the satellite construction contracts, approximately 70%
of spacecraft cost is typically paid to the manufacturer during construction
prior to spacecraft delivery and satellite launch.  In addition, approximately
15% typically is paid after the satellite has been placed in orbit and has
satisfactorily completed in-orbit testing.  The remaining portion of the
spacecraft cost is payable periodically as performance incentives over the
designated design life of the satellite contingent upon continued successful
operation of the satellite during the respective periods.

                                       6
<PAGE>
 
     Under the launch service contracts, launch services costs are typically
paid in quarterly installments with the final payment due at the end of the
planned launch period.  Launch payments are payable in full whether or not the
launch has resulted in launch success.

     INTELSAT has purchased launch and post-separation insurance coverage for
possible losses that may occur during the launch and subsequent one-year periods
for satellites scheduled for launch from 2000 through 2002.  The coverage
includes the cost of the satellite, launch services and associated capitalized
interest, as well as the cost of the insurance itself.  This insurance protects
the Corporation in proportion to the Corporation's interest in INTELSAT.  Launch
and post-separation insurance for the INTELSAT satellites does not protect the
Corporation against business interruption, loss or delay of revenues and similar
losses and may not fully reimburse the Corporation or INTELSAT for their
respective expenditures.  Beyond this one year post-separation period, the
Corporation and INTELSAT intend to rely on the spare capacity on the satellite
fleets, to the extent available, to avoid an interruption of customer service
and revenues.  Neither INTELSAT nor the Corporation procures insurance for the
in-orbit failure of satellites beyond the one-year, post-separation period.  In
the event of a complete in-orbit failure beyond the one-year, post-separation
period, the Corporation would be required to write off the value of its
proportionate investment in that satellite.  Partial in-orbit failures will be
evaluated for impairment according to the provisions of SFAS No. 121,
"Accounting for the Impairment of Long-Lived Assets to be Disposed of."

     Effective January 1, 1998, the Corporation changed its accounting policy
with respect to the cost of series satellites lost at launch or in orbit and its
accounting policy with respect to satellite performance incentives paid to
manufacturers.  See Note 5 to the financial statements.

     INTELSAT generally offers long-term commitments for transponder capacity of
one, two, three, five, ten or fifteen years for a range of services at tariff
rates which are progressively lower for the longer term commitment periods.  As
of December 31, 1998, COMSAT had commitments with INTELSAT of five years or more
in effect representing approximately 66.34% of COMSAT's total analog services
traffic with INTELSAT, 63.5% of its total digital services traffic with
INTELSAT, 81% of its total voice service with INTELSAT and 91% of its total
video service traffic with INTELSAT.  Approximately 54% of COMSAT's commitments
with INTELSAT are for a fifteen year term.

New Skies and INTELSAT Privatization

     The Corporation continues to promote efforts to restructure the INTELSAT
satellite system.  See "Business - Investments - New Skies Satellites, N.V.,"
"Item 7: Management's Discussion and Analysis of Financial Condition and Results
of Operations - Outlook - Satellite Services - Restructuring of INTELSAT and
Inmarsat" and Note 6 to the financial statements.

Regulation of CWS

     Under the Satellite Act and the Communications Act, COMSAT is subject to
regulation by the FCC with respect to CWS's communications services and the
rates charged for those services.  CWS provides its services on a non-
discriminatory basis to all customers, either under tariffs filed with the FCC
or on the basis of inter-carrier contracts.

                                       7
<PAGE>
 
     On April 24, 1998, the FCC granted the Corporation's petition for
reclassification as a non-dominant common carrier in markets that represent
approximately 90% of CWS's revenues.  For those markets, rate-of-return
regulation was lifted immediately.  On February 10, 1999, the FCC eliminated
COMSAT's remaining rate-of-return regulation along thin routes in favor of
COMSAT's incentive-based pricing plan.  See "Item 7: Management's Discussion and
Analysis of Financial Condition and Results of Operations - Outlook - Regulatory
and Legislative Developments."
 
     On October 28, 1998, the FCC issued a separate notice of proposed
rulemaking to explore the implications of enabling users to have direct access
to the INTELSAT system, which would end COMSAT's status as the exclusive
provider of INTELSAT services in the U.S.  In the direct access notice, the FCC
tentatively concluded, among other things, that it lacks the statutory authority
to impose Level 4 direct access (by which users could invest and acquire an
ownership interest in INTELSAT), but does have the authority to require Level 3
direct access (by which users could directly contract with INTELSAT for capacity
and bypass COMSAT).  The FCC sought comments on its tentative conclusion that it
would serve the public interest to mandate Level 3 direct access.  The
Corporation filed comments contesting the basis for the FCC's proposed action.
See "Item 7: Management's Discussion and Analysis of Financial Condition and
Results of Operations - Outlook - Regulatory and Legislative Developments."

     In November 1997, the FCC issued an order in its "DISCO-II" rulemaking
proceeding addressing, among other matters, COMSAT's provision of INTELSAT
services within the United States.  The FCC ruled that, before COMSAT may
provide such domestic satellite services, it must first waive the limited
immunity from suit which it has with respect to its actions as U.S. Signatory to
INTELSAT. COMSAT has appealed that ruling on the ground that its limited
immunity arises from international agreements entered into by the U.S. which may
not be abrogated by the FCC.

     COMSAT General is licensed by the FCC to operate the MARISAT F-2 and
COMSTAR D-4 satellites and is the licensee of a number of earth stations, which
are chiefly located at Clarksburg, Maryland.  There are also several earth
stations located at Clarksburg, Maryland and Paumulu, Hawaii that are licensed
to the Corporation for use by CWS.  In addition, CGSI is the licensee of two
earth stations located at Clarksburg, Maryland.  See "Item 2: Properties."

Competition

     CWS is subject to substantial and increasing competition from satellite
service providers, undersea cable operators and fiber optic cable systems.
Currently there are more than fifty satellite operators with over 180
geostationary satellites providing services around the globe.  Of those, over 50
satellites are capable of providing international service to or from the U.S. in
competition with COMSAT. Competing satellite service providers offer a full
range of services.  Voice and data services are provided by numerous satellite
systems, including Hughes/PanAmSat, Loral/Orion, GE Americom, Columbia
Communications, JSAT and others.  A number of satellite systems provide video
service in direct competition with COMSAT and INTELSAT, including
Hughes/PanAmSat, Loral/Orion, Columbia Communications and regional satellite
systems (e.g., Hispasat, JSAT, and France Telecom).  Many of the Corporation's
competitors have plans to substantially expand capacity over the next few years.
 
     COMSAT is currently the only U.S. entity that may provide international
space segment to customers using INTELSAT satellites.  In the above-mentioned
FCC direct access proceeding, CWS's 

                                       8
<PAGE>
 
largest customers have asked the FCC to allow direct access to the INTELSAT
system, and have also asked the FCC to nullify their long term contracts with
CWS pursuant to the so-called "fresh look" doctrine. The Corporation has opposed
these requests. For additional information concerning direct access and "fresh
look," see "Item 7: Management's Discussion and Analysis of Financial Condition
and Results of Operations -Outlook - Regulatory and Legislative Developments."
 
     In addition to the competitors described above, COMSAT also faces
competition from other countries' INTELSAT Signatories in the provision of
voice, video and data services.  Earth stations located in other countries that
are within the footprint of satellites sending signals to U.S. earth stations
may be providing service to customers in the U.S. by routing traffic through a
non-U.S. earth station connected to U.S. customers by domestic satellite or
fiber optic cable.  Such competitive service is believed to be primarily offered
by Canada's Signatory, Teleglobe, but may also be available from other
countries' Signatories, including Mexico.
 
     COMSAT also faces significant competition from service providers utilizing
undersea fiber optic cable systems to provide voice, data, and video services.
Fiber optic undersea cable is increasingly being used to carry transoceanic
video programming.  CWS's major carrier customers (including its three largest
customers, AT&T, MCI WorldCom and Sprint) are co-owners of fiber cable systems.

                          COMSAT Mobile Communications

Services

     CMC provides satellite telecommunications services for maritime,
aeronautical and land mobile applications, primarily using Inmarsat satellites.
CMC operates land earth stations in Southbury, Connecticut and Santa Paula,
California, which serve the Atlantic and Pacific Ocean Regions, respectively,
and in Malaysia and (until CMC's lease expires on June 30, 1999) Turkey, which
serve the Indian Ocean Region.  These stations enable CMC to offer global
coverage for its services.  There are currently approximately 143,000 mobile
terminals operating in the Inmarsat system.  As described below, CMC provides a
full range of voice, facsimile, data and telex services, as well as certain
value-added services.

Maritime Services

     CMC provides satellite services for communications to and from ships and
other vessels. Customers for these services include transport ship operators,
cruise ships and their passengers, fishing vessel operators, oil and mining
interests, pleasure boat operators, U.S. Navy ships and foreign
telecommunications administrations.

     In addition to telephony services, CMC's services include group call
messaging to a fleet of ships, electronic mail services, a direct-dial telephone
service for passengers and crew on board ships, a news summary distribution
service, access to data bases through personal computers, and other office
communications services for facsimile transmissions, worldwide teleconferencing
and current financial news reports.

                                       9
<PAGE>
 
     In May 1998, CMC implemented service with the U.S. Coast Guard (USCG) and
the National Oceanic and Atmospheric Administration (NOAA) to provide Inmarsat
standard-C services in support of USCG position reporting and NOAA survey
programs.

     CMC offers three digital services, Inmarsat-B, Inmarsat-C and Inmarsat-M,
in the Atlantic, Pacific and Indian Ocean Regions.  These services provide more
efficient use of the Inmarsat satellite capacity, help to significantly lower
the cost of using satellite communications, and expand the potential customer
base for maritime and land mobile services.  CMC also offers a multi-channel
version of Inmarsat-M service that allows cruise ships and other high-volume
users to increase their channel capacity and offer lower rates to their
customers.

     In October 1998, CMC entered into a nine year agreement with AT&T to
provide global satellite communications for "Afloat Personnel Telecommunications
Services" on board U.S. Navy vessels.  CMC will provide bulk capacity satellite
services to AT&T to support telephone service for sailors at sea.

Aeronautical Services

     CMC provides satellite telecommunications services for aeronautical
applications, including airline operational and administrative communications,
passenger telephone service and, prospectively, air traffic control.  Customers
of CMC for international aeronautical services include airline service
providers, commercial airlines, government aircraft and corporate aircraft.

     CMC provides aeronautical services with a data service for cockpit
communications on commercial flights under an agreement with Aeronautical Radio,
Inc., an airline-owned service organization.  CMC also provides aeronautical
voice services in the Atlantic and Pacific Ocean Regions through its earth
stations at Southbury, Connecticut and Santa Paula, California.  There are
currently more than 1,600 aircraft equipped to use the Inmarsat aeronautical
system, equally split between voice and data services.

     A service agreement with Kokusai Denshin Denwa Co., Ltd. (KDD), the
Japanese Signatory to Inmarsat, provides that CMC may use KDD's ground earth
station serving the Indian Ocean Region to serve CMC's aeronautical customers,
and CMC may serve KDD's customers flying in the Atlantic Ocean Region.  Under
the agreement, CMC and KDD provide mutual back-up in the Pacific Ocean Region
for aeronautical customers of both companies.

     A service agreement with GTE Airfone, Inc., a provider of air-to-ground
passenger telephone service using terrestrial facilities, enables it to extend
its current service to transoceanic flights by acquiring satellite and ground
earth station services from CMC.

     CMC has been selected by United Airlines to provide satellite
communications services for passengers (including telephone, fax and data
transmission) on approximately 104 United Airlines aircraft.  CMC has provided
financing for 74 of these aircraft of up to $7 million to promote the use of
satellite phones on United Airlines aircraft.  The $7 million facility is being
drawn upon as United Airlines installs seat-back phones on those aircraft.

                                       10
<PAGE>
 
     CMC also has been selected to provide satellite communication services to
the international fleet of  Delta Airlines.  CMC entered into agreements with
AT&T Wireless, Inc. to provide satellite communications to the passenger cabins
and with DeltaTel, Inc. to provide cockpit communications. CMC has implemented
service with AT&T to accept the use of the AT&T calling card to support this
service offering.  In addition, COMSAT provides voice service to Air Canada
passengers pursuant to an existing arrangement which commenced in 1994.

     In late 1996, the Federal Aviation Administration (FAA) selected CMC to
provide satellite and uplink services for the Wide Area Augmentation System
(WAAS).  In July 1998, CMC signed a five year $57 million agreement with the FAA
to complete the agreement and began earth station services.

Land Mobile Services

     CMC provides telecommunications services for international land mobile
applications, using mobile and portable terminals located outside of the United
States.  Customers for these services include broadcasters, foreign
telecommunications authorities and U.S. and foreign corporations and government
agencies.

     CMC's land mobile services are currently available using transportable
versions of Inmarsat's Inmarsat-A and Inmarsat-B mobile earth stations
(telephone, facsimile, data, and telex), a briefcase-size Inmarsat-M terminal
and a smaller data-only Inmarsat-C terminal through CMC's C-Link service.  C-
Link service is a low-cost text messaging service that permits smaller vessels
and land mobile units to use the global satellite network.  The briefcase-size
Inmarsat-M terminals provide a more portable and less expensive telephone
service for the news media, government officials and others who travel to remote
parts of the world where reliable communications services are often not
available.

     The Corporation commenced commercial Planet 1 service in January 1997.  The
Planet 1 terminal is a six pound, laptop computer-sized satellite terminal which
utilizes the Inmarsat-3 satellites.  CMC has entered into a number of agreements
to resell Planet 1 service.

Revenues

     Approximately 27% of the Corporation's consolidated revenues in 1998 were
derived from CMC (compared to 30% in 1997 and 30% in 1996).  No single customer
of CMC provided more than 10% of the Corporation's consolidated revenues in
1998.  See Note 16 to the financial statements.

Inmarsat

     Pending its expected privatization in April 1999, Inmarsat is an 87-nation
organization headquartered in London, England.  It operates under three
agreements: an intergovernmental convention; a headquarters agreement with the
United Kingdom (U.K.) Government; and an operating agreement signed by each
member nation's government or designated telecommunications entity (a
Signatory).

     COMSAT is the U.S. Signatory.  It represents the U.S. in Inmarsat, subject
to instructions from the Department of State (in concert with the Department of
Commerce and the FCC) on matters that may affect U.S. national interest and
foreign policy.

                                       11
<PAGE>
 
     Each Signatory has rights and obligations in Inmarsat analogous to those of
a partner.  Each owns an investment share, makes proportionate contributions to
Inmarsat's capital costs, and receives proportionate distributions of Inmarsat's
space segment charges after deductions for operating expenses. The investment
shares are typically readjusted as of February 1 of each year to approximate the
signatories' respective portions of the total utilization of the Inmarsat space
segment for the previous year. Due to the expected privatization of Inmarsat in
April 1999, this readjustment did not occur as of February 1, 1999.  COMSAT's
investment share, the largest in Inmarsat, was 22.2% as of December 31, 1998 as
compared to 23.0% at December 31, 1997.  At December 31, 1998, total Inmarsat
owners' equity was approximately $850 million.

     The Corporation continues to promote efforts for the privatization of
Inmarsat.  Inmarsat is expected to become an independent commercial company in
April 1999.  The privatization will affect the manner in which the Corporation
accounts for its ownership interest in Inmarsat.  See "Item 7: Management's
Discussion and Analysis of Financial Condition and Results of Operations -
Outlook - Satellite Services - Restructuring of INTELSAT and Inmarsat."

     The Inmarsat-3 satellites are the primary operational Inmarsat spacecraft
and are used for on-demand services such as Inmarsat A, B, M, Mini-M, C, and
Aeronautical. Some services such as Mini-M and Aero-I are spot beam only
services and can only be supported on the Inmarsat-3 satellites.  Four of the
Inmarsat-3 satellites are the primary operational Inmarsat spacecraft and are
used for on-demand services such as Inmarsat A, B, M, Mini-M, C, and
Aeronautical.  The fifth Inmarsat-3 satellite is planned to be used primarily
for bulk services and backup capacity.

     The Inmarsat-2 satellites are expected to provide full time pre-emptible
services and  backup for global beam services on the Inmarsat-3 satellites. Four
Inmarsat-2 satellites are in orbit.

     Inmarsat procured the Inmarsat-2 and Inmarsat-3 satellites and launch
services under long-term, multi-satellite contracts which provided for payments
by Inmarsat over the contract periods.   The contracts for the construction of
the Inmarsat-3 satellites required performance-based incentive payments for each
satellite after 60 days of successful in-orbit testing and after successful
emergence of the spacecraft from the first eclipse season.  Additional incentive
payments are made quarterly based on continuous satisfactory operation of the
satellite through the end of its orbital life.  Incentive payments were not paid
by Inmarsat in connection with the procurement of the Inmarsat-2 satellites.

     As of December 31, 1998, Inmarsat did not have any contracts to procure
additional satellites.

     All of the existing Inmarsat satellites have been in orbit for more than
one year and, as a result, are no longer insured for in-orbit loss under the
terms of the insurance policies procured at the time of launch.  Neither
Inmarsat nor the Corporation procures insurance for the in-orbit failure of
satellites beyond the one-year, post-separation period.  In the event of a
complete in-orbit failure of an existing Inmarsat satellite, the Corporation
would be required to write off the value of its proportionate investment in that
satellite.  The Corporation evaluates partial in-orbit failures and determines
whether a write-off is appropriate based on the degree of impairment.  The
Corporation also does not procure insurance to protect against business
interruption, loss or delay of revenues and similar losses for potential in-
orbit failure of the Inmarsat satellites.  The Corporation and Inmarsat rely on
spare and preemptible capacity 

                                       12
<PAGE>
 
on the satellite fleets, to the extent available, to minimize potential
interruption of customer service and revenues in the event of an in-orbit
failure.
 
     Effective January 1, 1998, the Corporation changed its accounting policy
with respect to the cost of series satellites lost at launch or in orbit and its
accounting policy with respect to satellite performance incentives paid to
manufacturers.  See Note 5 to the financial statements.

     Inmarsat generally offers its service providers satellite capacity on
demand generally under terms that require payments on a per minute basis.
Inmarsat has established a full period bulk capacity program which will increase
the inventory of satellite products that CMC can offer for future sale.

Regulation of CMC

     Under the Inmarsat Act, COMSAT is subject to regulation by the FCC with
respect to CMC's communications services and the rates charged for these
services.  CMC is currently regulated as a dominant carrier and its operations
are generally restricted to international service.  Regulatory constraints on
CMC are expected to be eased after Inmarsat is privatized.  However, upon
privatization of Inmarsat, CMC will no longer hold the legal status as the sole
authorized U.S. provider of Inmarsat service originating in the U.S.

     By an FCC Report and Order issued in 1989, COMSAT was authorized: (i) to be
the sole U.S. provider of Inmarsat space segment capacity for aeronautical
services; (ii) to provide ground segment aeronautical services in connection
with the Inmarsat space segment on a non-exclusive basis; and (iii) to provide
such aeronautical services only to aircraft engaged in international flights,
including international flights over U.S. airspace.  Another entity, the
American Mobile Satellite Corporation (AMSC), was designated to be the sole
provider of certain domestic aeronautical and land mobile satellite services.
In 1995, CMC applied to the FCC for authority to offer domestic aeronautical
services.  CMC's request is pending before the FCC.  In 1996, CMC began offering
domestic aeronautical services on an interim basis pursuant to temporary
authority granted by the FCC.  The FCC has regularly renewed COMSAT's temporary
authorization, and COMSAT continues to offer domestic aeronautical services
thereunder.

     COMSAT is not generally authorized to provide U.S. domestic land mobile
services.  In limited circumstances, the Corporation provides U.S. domestic
service to certain individual end users under special temporary authorities from
the FCC.

     In November 1997, the FCC issued an order in its "DISCO II" rulemaking
proceeding addressing, along with other issues, COMSAT's provision of Inmarsat
services within the United States.  The FCC ruled that, before COMSAT may
provide domestic service within the United States via Inmarsat, it must first
waive its immunity from suit, including suit under the U.S. antitrust laws,
stemming from its role as U.S. Signatory to Inmarsat.  The new commercial entity
which will be created upon the privatization of Inmarsat will not have the
privileges and immunities that the current Inmarsat inter-governmental, treaty-
based organization has currently.  COMSAT's limited privileges and immunities in
respect of the successor to Inmarsat also will be eliminated.  Absent that
impediment, the Corporation expects that the FCC will grant it authorization to
offer Inmarsat services within the United States following privatization.

                                       13
<PAGE>
 
Competition

     CMC competes internationally in the provision of voice, fax and data
communications services over the Inmarsat satellite system.  CMC's maritime,
land and aeronautical customers have access to a broad array of alternative
service providers and communications technologies, including:

     .    Inmarsat services provided by other Inmarsat distributors and
          resellers;
     .    High Frequency (HF), Very High Frequency (VHF) and other forms of
          maritime radio;
     .    C-Band and Ku-Band Satellites (maritime C-Band for cruise ships and
          VSAT systems on land using Ku-Band);
     .    Regional Satellite Systems (AMSC, TMI, and others used for land and
          maritime);
     .    Cellular (used widely on land, and in maritime coastal markets);
     .    New Global Satellite Systems (such as the low earth orbit satellite
          system of Iridium); and
     .    Terrestrial-based aeronautical.

     Under the Inmarsat Act, COMSAT is the designated U.S. Signatory to the
Inmarsat Operating Agreement, and is the sole U.S. operating entity and investor
in the Inmarsat system.  CMC competes for maritime, land mobile and aeronautical
communications business with other Inmarsat Signatories operating land earth
stations and with IDB Mobile Communications, Inc. (IDB), another U.S. land earth
station operator and a subsidiary of Stratos Global Corporation, which became
Canada's Signatory in 1998.  IDB provides maritime, land mobile and aeronautical
services through its own U.S. land earth stations using Inmarsat satellite
capacity obtained from a foreign Signatory.  COMSAT is currently involved in
legal proceedings against IDB.  See "Item 3: Legal Proceedings."
 
     With regard to U.S.-originating shore-to-ship Inmarsat traffic, COMSAT
currently has the exclusive right under the Inmarsat Act to be the provider of
Inmarsat space segment.  Nonetheless, COMSAT currently competes with another
land earth station operator, IDB, for shore-to-ship traffic. MarineSat
Communications Network and Marine Telecommunications Network also have FCC
licenses to provide these services in competition with COMSAT as resellers.
 
     COMSAT competes directly with a number of other Inmarsat Signatories that
operate land earth stations around the world and offer many of the same services
as COMSAT.  These include British Telecom, France Telecom, Station 12 (the
Netherlands), Telstra (Australia), Stratos (Canada), Deutsche Telecom, KDD
(Japan) and Telenor (Norway).  A total of 16 Signatories offer global service,
and a number of others offer service in one or more ocean regions.  In addition,
there are U.S. carriers licensed to resell Inmarsat services, including IDB,
Stratos Mobile Networks, and MarineSat Communications Network (subsidiaries of
Stratos Global Corporation) and Marine Telecommunications Network (a subsidiary
of ICG Satellite).

     Inmarsat's competitive environment is very different from that of INTELSAT,
in which a given call between two countries is "shared," with each country
accounting for one "half-circuit."  Inmarsat instead relies on a demand-assigned
mode of operation which results in a high degree of intra-system competition
among the more than 30 Inmarsat land earth station operators (LESOs) that
compete for traffic generated from Inmarsat's approximately 143,000 system-wide
terminals.  Each time a call from an Inmarsat mobile terminal is made, the end-
user placing the call can select any land earth station that 

                                       14
<PAGE>
 
serves the respective Inmarsat satellite to complete his transaction. COMSAT and
all LESOs effectively compete for each and every mobile-originated Inmarsat call
as it is made.

     Additionally, Inmarsat recently adopted a plan to privatize in April 1999.
As a result, COMSAT will lose its present status as sole provider of Inmarsat
satellite capacity for U.S. shore-to-ship traffic and for U.S. land earth
stations.  With privatization, competition among Inmarsat service providers is
expected to increase for shore-to-ship services.  See "Item 7: Management's
Discussion and Analysis of Financial Condition and Results of Operations -
Outlook - Satellite Services -Restructuring of INTELSAT and Inmarsat."
 
     Inmarsat's most significant competitor in the provision of maritime
communications is VHF radio for short distance or coastal communications, along
with Medium Frequency (MF) and HF radio for communications over long distances.
In addition to serving the communications needs of small vessels which operate
in coastal waters, maritime radio provides a lower-cost alternative to Inmarsat
services for ships which must comply with GMDSS carriage requirements.  It is
difficult to estimate the number of maritime radio coast stations or ship
terminals in service around the world.  However, in the United States alone, an
estimated 600,000 maritime radio licensees, utilizing more than 300 public coast
stations, rely on maritime radio for ship-to-ship and ship-to-shore
communications,  including calls that are interconnected to the terrestrial
public switched network.  There are approximately 10 licensed operators of
public coast stations in the United States.  Major operators of global maritime
radio networks serving the United States include MariTEL, Globe Wireless, and
Maritex.
 
     Maritime C-Band is used for a large volume of maritime communications
traffic from cruise ships sailing in the Caribbean and Alaskan regions for ship-
to-shore and shore-to-ship communications. Whereas Inmarsat-based operators such
as COMSAT were previously the largest communications providers to cruise ships,
in recent years these customers have increasingly been serviced by Maritime C-
Band operators such as MTN that use the satellite capacity of Hughes/PanAmSat,
INTELSAT and others.

     CMC also faces competition from cellular service.  A significant amount of
maritime traffic in U.S. and nearby waters operates within range of shore-based
cellular, and many of these ships rely heavily on cellular service.  Cellular
competes with CMC for coastal communications traffic from passenger ships,
fishing vessels and pleasure craft operating in the Caribbean, Alaskan fishing
regions and along the U.S. coastline.  The rapid build-out of cellular networks
around the world also provides competition to CMC's land mobile services.

     CMC competes in the maritime and land mobile markets with a number of
regional mobile satellite systems that operate using their own GEO satellites.
These include AMSC (serving North and Central America), TMI (Canada), MobilSat
(Australia/New Zealand) and N-Star (Japan).  Though COMSAT has been foreclosed
by FCC regulations from competing with AMSC for land mobile traffic in the
United States, both companies actively compete for customers operating in U.S.
coastal waters. AMSC's services are sold through their exclusive distributor,
Stratos Mobile.  Because the United States, pursuant to the 1997 WTO Basic
Telecommunications Agreement, committed to open up its markets to foreign
competition, foreign-licensed satellite operators using regional satellites can
now routinely offer services in the United States.  For example, TMI, a Canadian
company, has applied to provide land 

                                       15
<PAGE>
 
mobile satellite services in the United States using the Canadian MSAT-1
satellite and the FCC recently authorized a U.S. company, SatCom, to provide
such services via MSAT-1.

     CMC now competes with Iridium, the first of several proposed low-earth-
orbit (LEO) satellite providers, to complete its satellite network.  Iridium
began commercial service in November 1998. Iridium uses a network of 66
satellites to offer voice and paging services on a global basis, and is now
competing directly with Inmarsat for provision of global mobile satellite
services.  Due to its low-earth orbit system, Iridium is able to utilize smaller
handheld terminals which are easier to carry than the smallest laptop size
terminals currently needed for Inmarsat access.
 
     CMC also competes with VSAT services.  Inmarsat communications on land are
best suited for short-term, rapid deployment applications and are often used by
government, media and relief organizations for this purpose.  However, VSATs
offer a more cost effective alternative for customers whose communications
requirements are likely to involve more than two hours of traffic usage a day on
a long-term basis.  Today there are thousands of VSAT sites all over the globe,
many of which have been deployed to replace higher cost Inmarsat communications
or to provide for higher data transmission rates than Inmarsat.

     CMC faces competition from terrestrial radio networks to provide
aeronautical communications services.  Most aeronautical communications in the
United States rely on terrestrial radio networks operated by GTE Airfone, AT&T
Wireless and ARINC.  Satellite-based systems are less frequently used for such
communications and represent a smaller segment of the overall aeronautical
communications services market.

     FCC decisions also may significantly affect the competition for products
and services offered by CMC.  See "- Regulation of CMC."

                              COMSAT INTERNATIONAL

Services

     CI operates an integrated group of telecommunications companies that are
engaged principally in providing individualized digital network solutions to
business clients and carriers in selected markets. CI also is exploring the
development of prospective international telecommunications opportunities that
are consistent with its digital networking strategy.  CI's existing and
prospective companies typically are and will be located in those rapidly growing
markets where a significant number of CI's existing or targeted clients are
located (or where they intend to locate).

     As of December 31, 1998, CI operated in 11 countries located in Latin
America, Asia and Europe. CI's companies generally are wholly- or majority-
owned, with one exception.  At December 31, 1998, CI beneficially owned 50% of
COMSAT Max Limited, CI's operating company in India.  CI's clients are typically
local, indigenous large and medium-sized corporations, national branches of
multinational corporations and major telecommunications carriers and consortia.

                                       16
<PAGE>
 
     The following chart sets forth the CI businesses as of December 31, 1998:

<TABLE>
<CAPTION>
CI Company                                 Country                                       CI Ownership Percentage
<S>                                        <C>                                           <C>
BelCom, Inc.                               Russian Federation & CIS                      100%
COMSAT Argentina, S.A.                     Argentina                                     100%
COMSAT Asia (L) Incorporated               China                                          55%
COMSAT de Colombia, S.A.                   Colombia                                      100%
Communicaciones Satelitales de Colombia    Colombia                                      100%
COMSAT Brasil Ltda.                        Brazil                                        100%
COMSAT de Guatemala, S.A.                  Guatemala                                     100%
COMSAT Max Limited                         India                                          50%
COMSAT Mexico S.A. de C.V.                 Mexico                                        100%
COMSAT Peru, S.A.                          Peru                                          100%
COMSAT Digital Services                    Turkey                                         85%
COMSAT Telecommunications Services         Turkey                                         64%
COMSAT Venezuela                           Venezuela                                     100%
</TABLE>

     CI continued to develop its businesses in 1998.  In particular, CI
purchased all outstanding minority shareholdings in its Latin American
companies, including 35% of COMSAT Peru, S.A. held by Avantec, S.A. and 6% of
Communicaciones Satelitales de Colombia held by several individual minority
shareholders.  As a result, all of CI's Latin American operations are now
wholly-owned companies.  Due to a restrictive regulatory environment, CI decided
to convert its Bolivian operations to inactive status, pending possible
liberalization and business opportunities in the future.

     CI employs various technologies including satellite, microwave, fiber
optic, frame relay and ATM in the design and implementation of network solutions
for its clients.  Each of CI's operations centers is open seven days per week,
24 hours per day to monitor, test, and provide help desk services to clients.

     CI provides a wide range of service options to its corporate clients from
basic provision and maintenance of the customer's network to full management of
the network including router and facility management, from each of CI's network
management centers.

     The services provided by CI operating companies depend on local regulations
and are built from the following "family" of offerings:

     .    COMSATLink  -  services that assure a constant dedicated circuit
          ----------                                                      
          between locations for the transmission of voice, data and video
          communications.  Customers use the service for applications requiring
          LAN interconnection, Internet access, and voice trunking both
          domestically and internationally.

     .    COMSATNet  -  a service connecting multiple locations to a central
          ---------                                                         
          host location or with each other.  Typical applications are point-of-
          sale networks, credit card verification, banking, lottery, Internet
          access, inventory management and others.  A wide range of speeds are
          available both domestically and internationally.

     .    COMSATCast  -  an effective solution for customers having one-way
          ----------                                                       
          (broadcast) data, audio and video requirements.  Transmission from a
          central location can be sent to many locations simultaneously for
          applications such as the distribution of financial market data, news,
          weather data, radio programming, corporate training and television
          programming.

                                       17
<PAGE>
 
     .    COMSATDVnet  -  a Dynamic Virtual Network service that takes
          -----------                                                 
          advantage of broadband technologies and flexible, cost-effective
          bandwidth allocation to bring high-performance data services tailored
          to the customers network and management needs. Uses include WAN and
          LAN interconnections, Internet access, remote database access, file
          transfer and sharing, E-mail, E-commerce, virtual private networks,
          packetized voice and video, order entry systems and more.  Speeds
          range from 64kbps to 45mbps.

     .    COMSATWeb  -  provides a variety of Internet service configurations
          ---------                                                          
          with integrated offerings under development now.

Sales and Marketing

     CI has direct sales personnel in each of its operations.  In some of the
larger countries, marketing agreements have also been established with various
companies to provide additional geographic coverage of the market.

     CI's target market consists of corporate clients, both national and
international, Internet service providers (ISPs) and telecommunications carriers
who need local presence for provision of corporate networks.

Regulation of CI

     CI's companies operate in various developing countries and are subject to
regulation by the local regulatory authorities in those countries.  Because the
regulatory environment in those countries is rapidly evolving as the local
economies are developing, CI's companies face increasing business uncertainties
which could have an adverse effect on their operations in those countries.

Competition

     CI's companies operate in numerous and diverse markets.  Competition in
these markets tends to be fragmented.  Competitors are different in each region
and in some cases, in each country in which CI operates.  The degree of
regulation and the level of competition in these countries varies considerably.
In some countries there is full competition, and in others competition is
limited by law.  The competitive conditions faced by each company are the result
of differing and changing regulatory policies and economic conditions.  In those
countries that have not yet undergone a substantial liberalization of their
telecommunications laws, CI's principal competitor is typically a version of the
local Postal, Telegraph and Telephone administration (PTT), together with a
limited number of companies that provide telecommunications services similar to
those offered by CI.  In countries that have liberalized their
telecommunications laws, CI typically faces greater competition than in less
liberalized markets.
 
     CI faces certain operational risks inherent to the countries in which it
operates.  These risks are typical of emerging markets and include changes in
government regulations and licensing requirements, tariffs, taxes, sanctions and
other trade barriers, exchange controls, bureaucratic impediments, political,
social and economic instability, inflation, devaluation, interest rate and
exchange rate fluctuations.  There can be no assurance that the current economic
difficulties faced in Asia, Russia, Brazil and elsewhere, or any future economic
difficulties, or any other risks enumerated above or otherwise, will not
adversely 

                                       18
<PAGE>
 
impact CI's existing or prospective customers, thereby affecting CI's ability to
generate revenues or otherwise having a material adverse affect on CI's
financial results and condition.

Revenues

     Approximately 18% of the Corporation's consolidated revenues in 1998 were
derived from CI (compared to 16% in 1997 and 11% in 1996).  No single customer
of CI provided more than 10% of the Corporation's consolidated revenues in 1998.
See Note 16 to the financial statements.

                              COMSAT LABORATORIES

Services

     COMSAT Laboratories provides technical consulting services and develops
communications products.  Technical consulting activities include the design and
development of advanced digital communications technologies, systems and
networking solutions.  COMSAT Laboratories also designs and develops
communications products and software for satellite access, networking
applications and satellite system planning and management.

     Customers include U.S. and foreign government agencies, commercial
entities, INTELSAT, Inmarsat and ICO Global Communications (Holdings) Ltd.
(ICO).  In addition, COMSAT Laboratories conducts research and development (R&D)
on a broad range of telecommunications devices, subsystems, transmission
systems, technologies and techniques in support of other COMSAT businesses.

     On-going contracts being performed in 1998 include: a contract with
Ericsson to design and develop the HPN ICONET ground facilities subsystems; a
consulting agreement with Iridium related to the design of its next generation
system; a contract with AT&T to deliver second generation Time Division Multiple
Access (TDMA) terminals; contracts with INTELSAT to design STRIP7 and develop a
software system for generation INTELSAT TDMA burst time plans; a contract with
NASA to provide operation and maintenance support for the ACTS (Advanced
Communications Technology Satellite) program; and a variety of technical
consulting contracts for INTELSAT, Inmarsat, ICO and other governmental and
private industry customers.

     COMSAT Laboratories won external contracts with a total value of $53
million in 1998.  Major new contracts awarded or begun in 1998 include: a
contract with INTELSAT for new TDMA infrastructure; a contract with Lockheed
Martin for the ACES In-Orbit-Test; a contract with WorldSpace; and a contract
with NASA for ACTS.  At December 31, 1998, COMSAT Laboratories' backlog of
orders totaled $50.5 million, as compared to $28.3 million at December 31, 1997.

     The Labs developed the Linkway 2000 product which is used commercially in
the Link One/SM/ service, a new global satellite networking solution.  The
Linkway 2000 product supports two advanced networking protocols, ATM and Frame
Relay.  Telecommunications carriers can use the Link One service and the Linkway
2000 product to extend international voice and data networks into remote
locations that do not currently have service.  ISPs can use this service to more
easily connect countries throughout the world to the U.S. Internet backbone.
The service can also be used by multinational corporations to network their
offices worldwide.

                                       19
<PAGE>
 
     COMSAT Laboratories incurred research and development expenditures of $3.2
million in 1998, a decrease of $0.5 million from 1997.  These expenditures were
largely attributed to the development of its broadband VSAT, ATM and software
products.

Revenues

     Approximately 7% of the Corporation's consolidated revenues in 1998 were
derived from the Labs (compared to 6% in 1997 and 8% in 1996).  See Note 16 to
the financial statements.

                            DISCONTINUED OPERATIONS

     During the second quarter of 1997, the Corporation began accounting for the
operations of both Ascent Entertainment Group, Inc. (Ascent) and substantially
all of COMSAT RSI, Inc. (CRSI) as discontinued operations.  See Note 3 to the
financial statements.  The Corporation distributed its 80.67% ownership interest
in Ascent to COMSAT's shareholders on June 27, 1997.  On June 25, 1998, COMSAT
completed the sale of substantially all of CRSI to a subsidiary of TBG
Industries, Inc. (TBG) for net cash proceeds of approximately $111.9 million,
after adjusting for changes in intercompany loans and advances.  The sale of
substantially all of the assets and liabilities of JEFA Wireless Systems, a
subsidiary of CRSI, was completed in a separate transaction in February 1998.
The Corporation has agreed to indemnify the purchasers of CRSI and JEFA against
certain losses.  See Note 3 to the financial statements.

     The Corporation has retained the long-term contract for the completion of
the 100 meter radio astronomy telescope at Green Bank, West Virginia.  CRSI's
$29 million claim for work performed under and relating to the Green Bank
contract, which is currently in arbitration, has been assumed by COMSAT. See
"Item 3: Legal Proceedings" and Note 3 to the financial statements.

     The Corporation has also retained Electromechanical Systems, Inc. (EMS), a
former subsidiary of CRSI.  EMS designs, manufactures and installs multi-axis
positioning control units (pedestals) for precision tracking and pointing for
air traffic control, weather, radar, communication and surveillance equipment.
EMS also provides repair and restoration service for various antenna pedestals
for its customers.  More than 90% of EMS's current business is with military and
government customers, nearly all in the U.S.  EMS and the Corporation have been
named as defendants in a pending qui tam lawsuit under the Civil False Claims
Act.  There is also a separate criminal investigation into the same allegations.
See "Item 3: Legal Proceedings" and Note 11 to the financial statements.

     CRSI previously owned a 53% equity interest in Plexsys International
Corporation (Plexsys). Plexsys ceased doing business on July 1, 1998.  This
investment was not sold to TBG in connection with the sale of CRSI and has been
written off by the Corporation.

                                       20
<PAGE>
 
                                  INVESTMENTS

New Skies Satellites, N.V.

     On November 30, 1998, INTELSAT transferred six satellites (five currently
in orbit and one scheduled to be launched during 1999) to New Skies.  New Skies,
which is headquartered in the Netherlands, is a separate company that is
independent of INTELSAT.  As of December 31, 1998, the Corporation owned 16.6%
of New Skies.  See "Item 7: Management's Discussion and Analysis of Financial
Condition and Results of Operations - Outlook - Satellite Services -
Restructuring of INTELSAT and Inmarsat" and Note 6 to the financial statements.

ICO Global Communications (Holdings) Limited

     As of December 31, 1998, the Corporation directly owned 1.6% of ICO.
Together with the Corporation's indirect ownership of ICO through its ownership
interest in Inmarsat, which is also an ICO shareholder, the Corporation owned an
aggregate of 3.7% of ICO.  See Note 6 to the financial statements.

     ICO was formed to provide hand-held satellite communications services
outside of the Inmarsat organization to allow a more commercial focus than the
current Inmarsat system.

     In 1997, COMSAT concluded agreements with ICO to construct, operate and
interconnect a "satellite access node" (SAN) in Brewster, Washington.  In
December 1998, COMSAT reached an agreement with ICO to transfer the SAN facility
back to ICO.  The agreement also waives any rights to distribute ICO services
that COMSAT may have obtained by virtue of its 1995 subscription agreement. In
consideration of its settlement agreement, COMSAT received a cash payment of
$4.5 million.  See "Item 7: Management's Discussion of Financial Condition and
Results of Operations - Consolidated Operations" and Note 6 to the financial
statements.

                                       21
<PAGE>
 
Item 2:   Properties

                               COMSAT PROPERTIES

Bethesda, Maryland Headquarters

     At year end 1998, the headquarters of the Corporation and the headquarters
of CWS, CMC and CI were located in a building in Bethesda, Maryland, which the
Corporation leases from a limited partnership in which it holds a 50% interest,
primarily as a limited partner.  The managing general partner also owns a 50%
interest in the partnership.  An affiliate of the managing general partner owns
the building site and has leased this site to the partnership.  In 1993, the
Corporation entered into a 15-year lease with the partnership for the building.
See Note 10 to the financial statements.

Clarksburg, Maryland Facility

     In 1997, the Corporation sold the office buildings and land at Clarksburg,
Maryland that serve as the headquarters of the Labs and CGSI.  The Corporation
leased back the office buildings and the land underlying its earth stations for
a ten-year lease term.  See Note 5 to the financial statements.  The Corporation
owns an earth station at Clarksburg, Maryland that is used by COMSAT General to
house its Satellite Control and Teleport Facilities as well as the Bandwidth
Management Center operated by CGSI for the U.S. Government CSCI Program.  The
Corporation also owns an earth station at Clarksburg, Maryland that is used by
CWS to provide TT&C services to INTELSAT.  CDTI provides turnkey satellite
services at Clarksburg, Maryland.

Other Properties

     The Corporation owns or leases 10 properties in the United States and
leases a sales office in Beijing, China.

     The Corporation owns earth stations at Santa Paula, California and
Southbury, Connecticut, and leases earth stations in Turkey (which lease expires
June 30, 1999) and Malaysia, that are used by CMC to provide mobile
communications services.  The Corporation owns an earth station at Paumalu,
Hawaii that is used by CWS to provide TT&C services to INTELSAT.
 
     COMSAT General owns 86.3% of the MARISAT Joint Venture, which operates the
MARISAT F-2, one of the three satellites launched in 1976, with capacity leased
to Fugro N.V., a Netherlands company.  The MARISAT F-1 and F-3 ceased commercial
operations in 1996.  COMSAT General owns the COMSTAR D-4 satellite (launched in
1981) with capacity leased to CMC and the U.S. Navy.

     CI leases or owns facilities in each of the countries in which it operates.
See  "Item 1: Business -COMSAT International" above for a listing of the
countries in which CI operates.

     The Corporation's properties are believed to be suitable and adequate for
the Corporation's business operations.

                                       22
<PAGE>
 
INTELSAT Satellites

     The Corporation's property accounts include CWS's pro rata share of
INTELSAT satellites.  The INTELSAT satellites currently in use and under
construction are described below.  As a result of the INTELSAT restructuring,
six INTELSAT satellites were transferred to New Skies on November 30, 1998.
Five of the transferred satellites were in use and one is under construction.
The transferred satellites are not included in the description below.  See "Item
7: Management's Discussion and Analysis of Financial Condition and the Results
of Operations -Outlook - Satellite Services - Restructuring of INTELSAT and
Inmarsat."

     There are three INTELSAT V and VA satellites continuing to operate in the
INTELSAT system. All of these satellites have reached the end of their design
lives and are operating in an inclined orbit. Their capacities range from 15,000
to 17,000 voice circuits or 51 to 57 television channels (or some combination of
each depending on the configuration of the satellite).  The satellites were
built by a predecessor to Space Systems/Loral.

     The INTELSAT VI series consists of five satellites, constructed by Hughes
Aircraft Company, now a subsidiary of General Motors Corporation. These
satellites have an average capacity of at least 24,000 bearer circuits or 87
television channels. The INTELSAT VI satellites, the last of which was launched
on October 1991, currently provide primarily backbone public switched network
(PSN) services in the Atlantic and Indian Ocean regions.

     The INTELSAT VII series consists of five satellites constructed by Space
Systems/Loral.  These satellites have an average capacity of at least 17,050
bearer circuits or 62 television channels (or a capacity of 62 36MHz units with
a typical minimum power range of 29 to 34.5 decibels relative to one watt (DBW)
at C-band and 44 DBW at Ku-band depending on the beam). The last INTELSAT VII
satellite was launched in June 1996. These satellites were designed to replace
the V/VA satellites. They provide improved utilization and flexibility, with
improved radio frequency power, enhanced Ku-band coverage and increased C-band
connectivity compared to the V/VA satellites.

     The INTELSAT VIIA series, also constructed by Space Systems/Loral, consists
of two satellites having an average capacity of at least 19,250 bearer circuits
or 70 television channels (or a capacity of 70 36MHz units with a typical
minimum power range of 29 to 36 DBW at C-band and 42.7 to 45 DBW at Ku-band
depending on the beam). Of the three INTELSAT VIIA satellites constructed, the
first INTELSAT VIIA satellite was successfully launched in May 1995; the launch
of the second VIIA, in February 1996, was a launch failure (see Note 5 to the
financial statements); and the third VIIA was successfully launched in March
1996. These satellites provide an enhancement over the VII satellites to meet
increased demand for high power Ku-band capacity. New cross-strapped
connectivity from Ku-band to C-band allows the provision of satellite news
gathering (SNG) service using a roving Ku-band Spot Beam in the uplink.

     The INTELSAT VIII series consists of three satellites constructed by
Lockheed Martin Corporation.  These satellites have an average capacity of
21,000 bearer circuits or 76 television channels (or a capacity of 76 36MHz
units with a typical power range of 29 to 34.5 DBW at C-band and 44 DBW at Ku-
band depending on the beam). All three INTELSAT VIII satellites were
successfully launched in 1997. They were designed primarily to complement the
INTELSAT VI satellites and meet growing 

                                       23
<PAGE>
 
demand for C-band services. The INTELSAT VIII series satellites provide new
television broadcast mode capability with simultaneous up link from the
Northeast zone beam and down link from three West zone beams. The INTELSAT VIII
series satellites also provide expanded SNG service with the capability to cross
connect any of the Ku-band spot beams to any of the global beams in certain
transponders.

     The INTELSAT VIIIA series consists of one satellite constructed by Lockheed
Martin Corporation.  The satellite has an average capacity of at least 11,600
bearer circuits or 38 television channels (or a capacity of 42 36MHz units with
a power range of 39.7 to 42 DBW at C-band and 50.4 to 51.7 DBW at Ku-band
depending on the beam).  The INTELSAT VIIIA (F-5) was launched in June 1998.
The INTELSAT VIIIA satellite is designed for users requiring high power together
with a wide coverage areas in C-band for the provision of services such as
video, VSAT applications and PSN.  It uses complex state-of-the-art antenna
technology to provide improved coverage of land areas of North and South
America.
 
     The INTELSAT IX series currently consists of five satellites.  As of
December 31, 1998, procurement of five satellites had been approved by the
INTELSAT Board of Governors.  These spacecraft are to be built by Space
Systems/Loral and are intended to replace the INTELSAT VI satellites between
2000 and 2002.  The INTELSAT IX satellites are expected to have an average
capacity of 98 36MHz transponders with a typical minimum power range of 31 to 47
DBW depending on the beam. The satellites will provide primarily high
connectivity backbone public network services in the Atlantic and Indian Ocean
regions.  The INTELSAT IX satellites will be INTELSAT's largest capacity
satellites with advanced communications and RF performance.

Inmarsat Satellites

     The Corporation's property accounts include CMC's pro rata share of
Inmarsat satellites.  The Inmarsat satellites currently used are described
below.  See "Item 7: Management's Discussion and Analysis of Financial Condition
and Results of Operations - Outlook - Satellite Services - Restructuring of
INTELSAT and Inmarsat."

     The second-generation Inmarsat satellite system, known as the Inmarsat-2
series, consists of four satellites constructed by an international consortium
led by British Aerospace Dynamics Corporation. These satellites are now used
primarily for bulk services and backup capacity.  The Inmarsat-2 satellites are
expected to be moved, depending on traffic demand,  to new orbital locations
where they will provide full time pre-emptible lease services.  The Inmarsat-2
series satellites also provide backup for global beam services on the Inmarsat-3
satellites. Some services such as Mini-M and Aero-I are spot beam only services
and can only be supported on the Inmarsat-3 satellites.

     The third-generation Inmarsat satellite system, known as the Inmarsat-3
series, consists of five satellites constructed by Lockheed Martin Astro Space.
These satellites use spot-beam technology, which allows reuse of the scarce
frequency resources allocated for mobile satellite communications.  The
Inmarsat-3 satellites are about eight times more powerful than the Inmarsat-2
series.  All five of these satellites were launched successfully.  Four of the
Inmarsat-3 satellites are the primary operational Inmarsat spacecraft and are
used for on-demand services such as Inmarsat A, B, M, Mini-M, C, and
Aeronautical. The fifth Inmarsat-3 satellite is planned to be used primarily for
bulk services and backup capacity.

                                       24
<PAGE>
 
Item 3:   Legal Proceedings

     In addition to the matters described below, certain legal proceedings,
which are either pending or known to be contemplated by governmental
authorities, to which COMSAT or any of its subsidiaries is a party are described
in Notes 10 and 11 to the financial statements.

     In 1995, the Corporation entered into a five-year agreement with News
Corporation to provide satellite services beginning in 1996.  In March 1996,
News Corporation unilaterally terminated this agreement.  The Corporation has
commenced a lawsuit against News Corporation to recover damages arising out of
the alleged breach of obligation to COMSAT, and against PanAmSat Corporation and
Televisa for allegedly inducing the breach.   News Corporation has asserted a
counter claim for return of the $5 million deposit it originally paid.

     Since November 1997, the Corporation has been in a dispute with IDB Mobile
Communications, Inc. and its parent, Stratos Global Corporation of Canada, about
IDB/Stratos' refusal to pay COMSAT as U.S. Signatory to Inmarsat for the
satellite capacity used by their U.S. land earth stations.  Stratos became
Canada's Signatory to Inmarsat in 1998.  COMSAT contends that IDB is required,
under contract and by U.S. law (including the Maritime Satellite Act of 1978),
to pay solely COMSAT for that U.S. satellite capacity.  IDB/Stratos contend they
are permitted to secure capacity from foreign Signatories. In February 1998 they
asked the FCC for a declaratory ruling to that effect, which COMSAT opposed; the
petition remains pending.  In January 1998, the Corporation sued IDB for breach
of contract.  The court dismissed the contract case but ruled that COMSAT could
seek to enforce its statutory rights at the FCC.  COMSAT has appealed this
ruling.  In January 1999, the Corporation filed a complaint at the FCC seeking
damages against IDB, which remains pending.  In addition, IDB/Stratos have three
applications pending at the FCC for authority to provide various Inmarsat
services, which COMSAT has opposed unless conditioned on use of satellite
capacity provided by COMSAT as U.S. Signatory.  Also pending at the FCC is a
complaint filed against COMSAT by IDB/Stratos in September 1997 challenging the
Corporation's rates for certain Inmarsat services.

     The Corporation has retained the long-term contract for the completion of
the 100 meter radio astronomy telescope at Green Bank, West Virginia.  CRSI's
$29 million claim for work performed under and relating to the Green Bank
contract, which is currently in arbitration, has been assumed by COMSAT. The
prime contractor has filed a counterclaim seeking $12.9 million in damages for
delay.  The claim and counterclaim are currently in arbitration.  There can be
no assurance that the Corporation will be successful in collecting all or any
portion of this claim.

     COMSAT and its subsidiaries are a party to various lawsuits and arbitration
proceedings and are subject to various claims and inquiries, which generally are
incidental to the ordinary course of its business.  The outcome of legal
proceedings cannot be predicted with certainty.  Based on currently available
information, however, management does not believe that the outcome of any matter
which is pending or threatened, either individually or in the aggregate, will
have a material adverse effect on the consolidated financial condition of the
Corporation.  Nevertheless, the outcome of such matters could materially affect
consolidated results of operations in a given year or quarter.

                                       25
<PAGE>
 
Item 4:   Submission of Matters to a Vote of Security Holders

     None.

                                       26
<PAGE>
 
                                    PART II

Item 5:   Market for Registrant's Common Equity and Related Stockholder Matters

     On December 31, 1998, there were 52,633,577 shares of common stock
outstanding.  Of this number, 18,958 were Series II shares  and 52,614,619 were
Series I shares.  Series II shares are shares held by communications common
carriers authorized to hold shares by the FCC.  Series I shares are held by
other persons.  As of December 31, 1998, the Corporation had 32,711 Series I
holders and 36 Series II holders of record.
 
     The principal market for COMSAT's common stock is the New York Stock
Exchange, where it is traded under the symbol "CQ."  COMSAT's common stock is
also listed on the Chicago Stock Exchange and the Pacific Stock Exchange in the
United States and on the Swiss Exchange.
 
     The Corporation's transfer agent, registrar and dividend disbursing agent
is The Bank of New York, 101 Barclay Street, New York, New York.

     The high and low sales prices of, and the dividends declared on, each share
of COMSAT common stock for the last two years are as follows:

<TABLE>
<CAPTION>
Calendar Year 1998     High     Low       Dividend
- --------------------  --------  --------  --------
<S>                  <C>       <C>          <C>
First Quarter         36        21  5/8     .05
Second Quarter        42 3/4    27  3/4     .05
Third Quarter         36 7/8    21 13/16    .05
Fourth Quarter        39 5/8    32  7/16    .05 

<CAPTION>

Calendar Year 1997      High      Low     Dividend
- --------------------  --------  --------  --------
<S>                  <C>       <C>          <C> 
First Quarter         28  1/2   23          .195
Second Quarter        26 11/16  19  5/8     .05 
Third Quarter         24  5/16  20 13/16    .05 
Fourth Quarter        25  3/4   20 5/16     .05  
</TABLE>

                                       27
<PAGE>
 
Item 6:   Selected Financial Data


<TABLE>
<CAPTION>
In thousands, except per share amounts             1998        1997         1996        1995        1994
- -----------------------------------------------------------------------------------------------------------
 
Summary of Operations
<S>                                            <C>         <C>          <C>         <C>         <C>
Revenues                                        $  616,469  $  562,651   $  545,100  $  507,687  $  500,687
Operating expenses                                 556,967     480,683      437,875     387,873     367,324
Operating income                                    59,502      81,968      107,225     119,814     133,363
Income from continuing operations                   26,417      28,568       36,197      43,507      69,245
Net income (loss)                                   26,417     (64,446)       8,622      37,817      77,642
Earnings (loss) per share-assuming dilution:
   Income from continuing operations                  0.50        0.57         0.74        0.91        1.47
      Net income (loss)                               0.50       (1.29)        0.18        0.79        1.65
 
Balance Sheet Data
Total assets                                     1,790,798   1,894,775    2,097,286   2,022,247   1,851,351
Long-term debt                                     446,832     461,960      578,379     590,378     511,474
Stockholders' equity                               659,040     586,271      841,817     839,433     826,916
 
Dividends
Dividends paid                                      10,393      16,975       37,698      36,874      33,547
Dividends paid per share                              0.20        0.35         0.78        0.78        0.76
Distribution of Ascent Entertainment Group,              -     194,633            -           -           -
   Inc. shares
</TABLE>

                                       28
<PAGE>
 
Item 7:   Management's Discussion and Analysis of Financial Condition and
          Results of Operations

                             ANALYSIS OF OPERATIONS

Consolidated Operations

Continuing Operations

     Consolidated revenues from continuing operations in 1998 were $616 million,
an increase of 10% as compared to the previous year.  This improvement was the
result of increases in all business segments. Consolidated revenues in 1997 were
$563 million, or 3% higher than 1996.  This increase was predominantly the
result of COMSAT International (CI) revenue growth as compared to 1996.

     Operating income from continuing operations in 1998 was $60 million, which
was $22 million below 1997. The decrease in operating income was primarily the
result of a $14 million impairment loss related to BelCom (a CI company
operating in Russia and the Commonwealth of Independent States) and increased
losses in CI of $12 million, which were primarily related to operations in
Brazil. In addition, 1998 results included $6 million of costs related to the
proposed merger with Lockheed Martin Corporation.  Improvements in operating
income in both the COMSAT Mobile Communications (CMC) and COMSAT World Systems
(CWS) segments totaling $14 million partially offset those items.
 
     Operating income from continuing operations for 1997 was $82 million, as
compared to $107 million for 1996. The 1997 decline in operating income was
primarily the result of lower operating income in the CWS, CMC and COMSAT
Laboratories (Labs) segments, partially offset by improvements in CI. The
decrease in CWS was primarily the result of a lower investment base in CWS,
which reduced operating income under rate of return regulation.  The decrease in
CMC was due to increased depreciation from new satellites. The decrease in the
Labs was due to the non-recurrence in 1997 of the positive impact in 1996 of a
licensing agreement that resolved a patent-infringement dispute.  Expenses of $4
million for a proxy contest and related litigation, which were settled in the
second quarter of 1997, also affected 1997 operating income.

     Other income (expense), net for 1998 was income of $13 million, which was
$9 million better than 1997.  This was primarily the result of a $15 million
gain from the sale of a portion of CI's investment in Viatel, Inc. and income of
$4 million from an agreement with ICO Global Communications (Holdings) Limited
(ICO) that settled a dispute between the corporation and ICO. See Note 6 to the
financial statements.  In addition, 1998 included a $2 million non-cash write-
off of the Labs' investment in Superconducting Core Technologies that partially
offset those items.  For 1997, other income (expense), net was income of $4
million, which was $11 million better than 1996.  This was primarily
attributable to a $7 million gain on the sale of the corporation's Clarksburg,
Maryland property and improvements in the results of CI's equity investments.
 
     Interest costs, net of amounts capitalized for 1998, were $40 million, or
$2 million lower than 1997.  The lower interest costs were due to the reversal
of $4 million of previously accrued interest costs related to income taxes
(discussed below in income tax expense) and lower borrowings as a result of the
use of the proceeds from the sale of COMSAT RSI, Inc. (CRSI) to reduce debt.
Lower amounts of 

                                       29
<PAGE>
 
interest capitalized due to the completion of satellites under construction
partially offset these decreases. Interest costs, net of amounts capitalized for
1997, were $42 million, which was $7 million higher than 1996. The increase
primarily reflected reduced interest capitalized as compared to 1996.
 
     Income from continuing operations before taxes and extraordinary item for
1998 was $32 million, or $12 million below the previous year.  This decrease was
principally due to the impairment loss related to BelCom, increased losses in
Brazil, merger costs and the non-recurrence of the gain on the sale of the
Clarksburg property.  The gain from the sale of Viatel stock and improvements in
both CMC and CWS partially offset those items.  Income from continuing
operations before taxes and extraordinary item for 1997 was $44 million, or $21
million below 1996. This was primarily the result of the factors noted above in
the discussion of operating income, partially offset by the 1997 gain on the
sale of the Clarksburg property.

     Income tax expense for 1998 was $6 million, compared to $16 million for the
previous year. In the third quarter of 1998, the corporation favorably resolved
a state tax audit and, accordingly, reversed previously accrued interest costs
of $2 million and state income taxes of $2 million.  In addition, events during
the third quarter led the corporation to determine that previously accrued
interest costs of $2 million and federal income taxes of $15 million related to
certain federal tax matters were no longer required.  See Note 14 to the
financial statements.   Excluding these tax benefits, the corporation's
effective tax rate was higher than the previous year as a result of not being
able to tax benefit the BelCom impairment loss and certain merger costs.  Income
tax expense in 1997 of $16 million was $13 million below 1996.  This was
primarily due to a decrease in income before taxes and an improved effective tax
rate due principally to a reduction in state income tax expense.

     Income for 1998 from continuing operations before extraordinary item was
$26 million, or $3 million below the previous year.  Income from continuing
operations before extraordinary item for 1997 was $29 million, as compared to
$36 million in 1996.

     Basic earnings per share for continuing operations before extraordinary
item for 1998 were $0.51, or $0.07 below 1997. For 1997, basic earnings per
share were $0.58, as compared to $0.76 for 1996. Diluted earnings per share for
continuing operations for 1998 were $0.50, a $0.07 decrease from 1997. Diluted
earnings per share for continuing operations for 1997 and 1996 were $0.57 and
$0.74, respectively.  See Note 12 to the financial statements.

     Extraordinary loss from early extinguishment of debt, net of tax, for 1997
was $4 million ($0.08 per share).  This represents the costs incurred in 1997
from the corporation's repurchase of $90 million of its 8.125% notes and $10
million of its 7.7% medium-term notes.  See Note 8 to the financial statements.

Discontinued Operations

     During the second quarter of 1997, the corporation began accounting for the
operations of both Ascent Entertainment Group, Inc. (Ascent) and substantially
all of CRSI as discontinued operations.  In 1997, the corporation recorded a
loss from discontinued operations, net of tax, of $89 million ($1.78 per share,
fully diluted).  This compares to losses of $28 million ($0.56 per share, fully
diluted) for 1996.  See Note 3 to the financial statements.

                                       30
<PAGE>
 
Consolidated Results

     On a consolidated basis, including discontinued operations and the
extraordinary item, net income for 1998 was $26 million as compared to a net
loss for 1997 of $64 million.  For 1996, the consolidated net income was $8
million.

     Basic earnings per share for 1998 were $0.51 as compared to basic losses
per share for 1997 of $1.32.  Basic earnings per share for 1996 were $0.18.
Diluted earnings per share for 1998 were $0.50 as compared to diluted losses per
share for 1997 of $1.29.  Diluted earnings per share for 1996 were $0.18.  See
Note 12 to the financial statements.

Segment Operating Results

     In accordance with Statement of Financial Accounting Standards (SFAS) No.
131, "Disclosures About Segments of an Enterprise and Related Information," the
corporation is reporting its operating results in four segments.  The Satellite
Services business unit consists of two segments -- CWS and CMC. The
corporation's other business units, CI and Labs, are being reported as separate
segments.  The corporation evaluates the performance of its operating segments
based on income (loss) before taxes and interest costs.  See Note 16 to the
financial statements.
 
     In the corporation's 1998 Form 10-Q reports and the 1997 Form 10-K,
operating results were presented in two segments -- Satellite Services and
Network Services.  The Satellite Services segment included CWS and CMC.  The
Network Services segment included CI, Labs and Government Programs. Effective
December 31, 1998, CI and Labs are reported as separate segments.  The results
of Government Programs are now included as part of the CWS segment.

                                       31
<PAGE>
 
<TABLE>
<CAPTION>
In millions                                   1998      1997      1996
- -----------------------------------------------------------------------
REVENUES
- --------
<S>                                         <C>       <C>       <C>
Satellite Services
  World Systems                              $303.1    $286.1    $297.8
  Mobile Communications                       169.1     167.9     160.9
                                            -------    ------    ------
    Total Satellite Services                  472.2     454.0     458.7
                                            -------    ------    ------
                                            
COMSAT International                          113.3      89.7      58.1
                                            
COMSAT Laboratories                            42.3      36.4      43.7
                                            
Eliminations and other                        (11.3)    (17.5)    (15.4)
                                            -------    ------     -----
                                            
    Total                                    $616.5    $562.6    $545.1
                                            =======    ======    ======
                                            
INCOME (LOSS) FROM CONTINUING OPERATIONS    
BEFORE TAXES AND EXTRAORDINARY ITEMS        
- ------------------------------------------  
Satellite Services                          
  World Systems                              $113.1    $102.7    $111.0
  Mobile Communications                        31.9      23.8      34.9
                                            -------     -----     -----
    Total Satellite Services                  145.0     126.5     145.9
                                            -------     -----     -----
                                            
COMSAT International                          (21.0)     (8.9)    (14.7)
                                            
COMSAT Laboratories                            (3.5)     (1.8)      7.3
                                            -------     -----     -----
                                            
    Total segment income before taxes         120.5     115.8     138.5
                                            
General and administrative expense            (25.6)    (23.2)    (23.9)
Merger costs                                   (5.5)        -         -
Other                                         (57.2)    (48.4)    (49.5)
                                            -------     -----     -----
                                            
    Total                                    $ 32.2    $ 44.2    $ 65.1
                                            =======    ======    ======
</TABLE>

 Satellite Services

     Satellite Services includes both the CWS and CMC operating segments.  CWS
provides satellite capacity for telephone, data, Internet, video and audio
communications services between the United States and the rest of the world
using the global satellite networks of the International Telecommunications
Satellite Organization (INTELSAT) and New Skies Satellites N.V. (New Skies). CWS
also includes the operating results of COMSAT Government Systems, Inc., COMSAT
Digital Teleport, Inc. and COMSAT General Corporation, which provide various
satellite and ground segment services to commercial and government customers.
CMC provides satellite telecommunications services for maritime, aeronautical
and land mobile applications, primarily using International Mobile Satellite
Organization (Inmarsat) satellites. COMSAT is the statutorily designated U.S.
participant in both the INTELSAT and Inmarsat satellite systems.
 
     Revenues in the Satellites Services business in 1998 were $472 million, an
increase of 4% over 1997.  For 1997, Satellite Services revenues were $454
million, or 1% below the previous year. Income before taxes for the Satellite
Services business in 1998 was $145 million, which was 15% better than 

                                       32
<PAGE>
 
1997. Income before taxes for Satellite Services in 1997 was $127 million, a
decline of 13% as compared to 1996.

World Systems

     Revenues in CWS for 1998 were $303 million, which was 6% higher than 1997.
The improvement in revenues was primarily the result of increased demand for
private data communication networks and Internet transmissions, partially offset
by declines in voice and video revenues.  CWS revenues for 1997 were $286
million, or 4% below 1996.  The decline resulted from lower full-time voice and
fiber optic restoration revenues, which were partially offset by increased
revenues from private data communication network leases and Internet traffic.
The lower voice revenues stemmed primarily from rate reductions provided to
AT&T, MCI and Sprint, CWS's three largest international carrier customers.
 
     Income before taxes for CWS in 1998 was $113 million, or 10% higher than
the previous year. The 1998 results include income of $4 million from a
settlement with ICO pursuant to which the corporation will transfer operation of
ICO's Satellite Access Node facility in the United States to ICO. See Note 6 to
the financial statements.  The balance of the improvement in income before taxes
was primarily due to higher revenues offset, in part, by increased depreciation
from placing new satellites in service.  For 1997, CWS's income before taxes was
$103 million, or 7% below 1996. The 1997 results reflect increased depreciation
from placing new INTELSAT satellites in service.

     On November 30, 1998, INTELSAT transferred six satellites (five currently
in orbit and one scheduled to be launched during 1999) to New Skies.  New Skies
is an independent company that was spun off from INTELSAT and is headquartered
in the Netherlands.  See Note 6 to the financial statements and Management's
Discussion and Analysis (MD&A) -- Outlook.
 
Mobile Communications
 
     Revenues in CMC for 1998 were $169 million, an increase of 1% compared to
last year.  In 1998, CMC recorded increased revenues from the contract with the
Federal Aviation Administration (FAA) on the Wide Area Augmentation System
(WAAS) and from traffic improvements in both digital telephone services and
aeronautical services.  Offsetting these improvements were lower sales of Planet
1 terminals and a decrease in telex revenues.  For 1997, CMC's revenues were
$168 million, an increase of 4% compared to the prior year. The higher revenues
were primarily the result of sales of Planet 1 terminals and service, the start
of the FAA WAAS contract and increased revenues from the Inmarsat system.
 
     CMC's income before taxes for 1998 was $32 million, which was 34% better
than 1997. The improvement in income was primarily the result of lower operating
costs offset, in part, by increased depreciation from the full-year impact of
new Inmarsat satellites placed in service.  Income before taxes for CMC in 1997
was $24 million, which was 32% below 1996. The decrease was primarily the result
of increased depreciation associated with new Inmarsat-3 satellites placed in
service during 1997 and increased costs related to Planet 1 service, which began
commercial operation in 1997.

                                       33
<PAGE>
 
COMSAT International

     CI operates an integrated group of telecommunications companies that are
engaged principally in providing individualized digital network solutions and
value-added services to business clients and carriers in selected emerging
markets.  As of December 31, 1998, CI operated in 11 countries worldwide.

     CI's revenues in 1998 were $113 million, or 26% higher than in 1997. The
higher revenues were principally due to growth in Argentina, Brazil and
Colombia.  In 1997, CI's revenues were $90 million, which was 54% better than
the previous year.  The 1997 increase in revenues in CI was driven primarily by
improvements in CI's operations in Brazil, Argentina and Venezuela.

     CI's loss before taxes in 1998 was $21 million, as compared to losses of $9
million in 1997. In the third quarter of 1998, CI recorded a non-cash impairment
loss of $14 million, which was related to the write-down of long-lived BelCom
assets, namely goodwill and plant and equipment. See Note 7 to the financial
statements.  In addition, CI had a $15 million gain from the sale of Viatel
stock. Exclusive of the BelCom impairment and the gain on the sale of stock,
CI's losses increased $13 million as compared to 1997.  The increased operating
losses were primarily due to higher depreciation, fixed asset adjustments and
contract losses in Brazil; increased losses in BelCom; and start-up costs in
Mexico. In 1997, the loss before taxes was $9 million, a $6 million improvement
over 1996.  The 1997 improvement was primarily the result of a decrease in
losses at BelCom.

COMSAT Laboratories
 
     COMSAT Laboratories provides technical consulting services and develops
advanced communications technologies and products for satellite access and
networking applications.

     The Labs' revenues for 1998 were $42 million, which was 16% higher than
1997.  This increase was due to improvements in technical consulting revenues.
Revenues in 1997 were $36 million, as compared to $44 million for 1996.
Included in 1996 revenues and income before taxes was $8 million related to a
licensing agreement that resolved patent infringement disputes with certain
manufacturers of television encryption and decryption equipment, which did not
reoccur in 1997.  Exclusive of the revenues related to this agreement, the Labs'
1997 revenues were at approximately the same level as 1996.

     The loss before taxes in 1998 for the Labs was $4 million, compared to $2
million in 1997. The 1998 loss included the first quarter 1998 non-cash $2
million write-off of the Labs' investment in Superconducting Core Technologies,
Inc.  The 1997 loss before taxes of $2 million compared to a $7 million profit
before tax for 1996.  The 1996 results included the $8 million of income related
to the agreement on patent disputes.

                                       34
<PAGE>
 
Outlook

     Many of the statements that follow are forward looking and relate to
anticipated future events and operating results.  Statements that look forward
in time are based on management's current expectations and assumptions, which
may be affected by subsequent developments and business conditions, and
necessarily involve risks and uncertainties.  These statements and the
corporation's future operating results may be affected by the timing and outcome
of regulatory and other governmental proceedings, legislative actions,
developments concerning the privatizations of INTELSAT and Inmarsat, the
proposed acquisition of COMSAT by Lockheed Martin Corporation, international and
domestic business conditions, increased competition from other satellite
services providers, the disposition of assets and completion of contracts placed
in discontinued operations, the effect of the year 2000 issue on COMSAT,
litigation and other factors.  Therefore, there can be no assurance that actual
future results will not differ materially from anticipated results.  Although
the corporation has attempted to identify some of the important factors that may
cause actual results to differ materially from those anticipated, those factors
should not be viewed as the only factors that may affect future operating
results.
 
Business Combination with Lockheed Martin

     On September 18, 1998, COMSAT entered into an Agreement and Plan of Merger
(the Merger Agreement) with Lockheed Martin Corporation (Lockheed Martin) and
Deneb Corporation (Acquisition Sub), a wholly-owned subsidiary of Lockheed
Martin.  Under the terms of the Merger Agreement, Lockheed Martin will acquire
all of the issued and outstanding common stock, no par value, of COMSAT (the
COMSAT Common Stock) in a two-step transaction.

     On September 25, 1998, a wholly-owned subsidiary of Lockheed Martin,
Regulus, LLC (Purchaser), initiated a tender offer to purchase up to 49%
(subject to certain adjustments) of the COMSAT Common Stock at a price of $45.50
per share in cash.  The tender offer is being made pursuant to the Merger
Agreement upon the terms and subject to the conditions set forth in the
Purchaser's Offer to Purchase, dated September 25, 1998 (the Offer to Purchase),
and the related Letter of Transmittal (which, together with the Offer to
Purchase, constitute the Offer).

     Certain significant conditions to the consummation of the Offer include:
(i) there being validly tendered and not withdrawn prior to the expiration date
of the Offer at least one-third of the COMSAT Common Stock; (ii) the approval by
COMSAT shareholders of the Merger (described below) and the Merger Agreement;
and (iii) the receipt of all required regulatory consents and approvals,
including the Purchaser having been authorized by the FCC to acquire  up to 49%
of the then outstanding Shares, subject to certain adjustments (such
authorization, and certain related FCC authorizations, the Authorized Carrier
Conditions, and expiration of all waiting periods under applicable antitrust
laws.  The Purchaser's obligation to consummate the Offer also is subject to
there not being any fact or circumstance that would reasonably be expected to
have a Material Adverse Effect (as defined in the Merger Agreement) on COMSAT or
a decline in the Standard & Poor's 500 Index of at least 27% from the date of
the Merger Agreement through certain specified measurement dates.

     The Offer is currently scheduled to expire on May 3, 1999.  Under the
Merger Agreement, however, Lockheed Martin has agreed to extend the Offer, for
periods of no more than 60 days, until the 

                                       35
<PAGE>
 
earlier of (i) September 18, 1999, or (ii) 10 business days after the date on
which the last of the Authorized Carrier Conditions shall have been obtained. At
Lockheed Martin's request, the Merger and Merger Agreement will be considered
for approval by COMSAT's shareholders at the corporation's annual meeting of
shareholders scheduled for June 18, 1999.

     The Merger Agreement provides that as soon as practical after consummation
of the Offer and the satisfaction or waiver of the conditions set forth therein,
COMSAT will be merged with Acquisition Sub (the Merger).  In the Merger, each
share of COMSAT Common Stock that is issued and outstanding immediately prior to
the effective time of the Merger (other than shares of COMSAT Common Stock held
by COMSAT, Purchaser or Lockheed Martin and dissenting shares, if any) will be
converted into the right to receive one share of common stock, par value $1.00
per share, of Lockheed Martin (the Lockheed Martin Common Stock), after
adjustment to give effect to a 2 for 1 stock split by Lockheed Martin effective
December 31, 1998 and subject to possible further adjustment as provided in the
Merger Agreement.

     Certain significant conditions to the consummation of the Merger include:
(i) the consummation of the Offer; (ii) the amendment of the Communications
Satellite Act of 1962 (the Satellite Act); and  (iii) the receipt of the
approvals of the FCC and other governmental authorities required for the
consummation of the Merger.  In addition, the obligations of Lockheed Martin and
Acquisition Sub to consummate the Merger are subject to there not being any fact
or circumstance that would reasonably be expected to have a Significant Adverse
Effect (as defined in the Merger Agreement) on COMSAT.

     On January 21, 1999, Representative Tom Bliley, Chairman of the House
Committee on Commerce, and Senator Conrad Burns, Chairman of the Senate Commerce
Subcommittee on Communications, sent a letter to William E. Kennard, Chairman of
the FCC, urging the FCC not to take any action to permit any company (including
Lockheed Martin and the Purchaser) to purchase more than 10 percent of COMSAT
prior to Congress adopting satellite reform legislation. If the FCC, in
deference to the position expressed in the letter, does not proceed with its
review of Lockheed Martin's filings related to the Offer, or if the FCC's review
does not otherwise proceed on the schedule Lockheed Martin anticipated, the
Offer may not be completed in the first half of 1999, the time frame previously
disclosed by Lockheed Martin and COMSAT as the time frame during which they
expected the Offer to close. Further, if the FCC were to delay or slow its
review, and if Congress does not make rapid progress on satellite reform
legislation, the Offer may not be completed by September 18, 1999.  If this
occurs, under the terms of the Merger Agreement, either party may terminate the
Merger Agreement.  The parties may also elect not to avail themselves of that
right or may elect to amend the Merger Agreement to extend this date.  If
Congress enacts legislation promptly, the Merger may be accelerated from the
year-end date previously estimated by Lockheed Martin and COMSAT as the date by
which they expected the Merger to close.  Conversely, if the legislative process
moves slowly, the Merger is unlikely to occur by year end. For information about
recently introduced satellite reform legislation, see Legislative and Regulatory
Developments below. No assurance can be given that the requisite legislation
will be enacted.  If legislation enabling the Merger is enacted, FCC approval of
the Merger (in addition to the Authorized Carrier Conditions) will still be
required.  While it is expected that the FCC would act promptly on the matter
following enactment of enabling legislation, the FCC's response time could
affect the estimated time frame for closing the Merger.

                                       36
<PAGE>
 
     In connection with the execution of the Merger Agreement, the parties
entered into certain ancillary agreements, including a Shareholders Agreement, a
Registration Rights Agreement and a Carrier Acquisition Agreement.  See Note 2
to the financial statements for a description of those agreements.

Restructuring of INTELSAT and Inmarsat

     Significant progress was made during 1998 and early 1999 with respect to
the corporation's ongoing efforts to restructure INTELSAT and Inmarsat.

     On November 30, 1998, INTELSAT transferred six satellites (five currently
in orbit and one scheduled to be launched during 1999) to New Skies Satellites
N.V. (New Skies).  New Skies, which is headquartered in the Netherlands, is an
entirely separate, independent company spun off from INTELSAT.

     Prior to the transfer from INTELSAT to New Skies of the six satellites, the
financial results related to those satellites were included in INTELSAT's
financial statements. Since the corporation uses the proportionate method of
accounting to account for its investment in INTELSAT, a portion of the financial
results related to those satellites also was included in the corporation's
financial results. COMSAT is using the cost method of accounting for its
investment in New Skies.  COMSAT's direct ownership of New Skies is
approximately 16%.  Under the cost method, COMSAT will recognize income only at
the time dividends from New Skies are received.  COMSAT does not anticipate that
New Skies will declare dividends during 1999 and for some period of time
thereafter.  During 1998, the corporation's share of pre-tax earnings related to
the satellites transferred to New Skies was approximately $3 million.  As a
result, CWS's 1999 pre-tax earnings will be lower by approximately this amount
in the absence of other factors that may affect operating results in CWS. COMSAT
continues to consolidate the remaining INTELSAT investment and recognizes its
portion of INTELSAT's results of operations each reporting period.  See Note 6
to the financial statements.

     In June 1998, the FCC issued a public notice requiring U.S. earth stations
licensees using INTELSAT satellites that were scheduled to be transferred to New
Skies to file license modification applications by July 17, 1998 in order to
access the New Skies system.  Several companies, including COMSAT, filed
applications in response to this notice.  In September 1998, a competitor of New
Skies filed a petition asking the FCC to deny the applications or alternatively
to grant the applicants special temporary authority to access New Skies for a
limited period and to defer the question of permanent authority to a later date.
COMSAT, New Skies, and several of the applicants opposed this petition.  The FCC
did grant special temporary authority to access New Skies following the November
30, 1998 asset transfer and indicated that it would act on the question of
permanent authority once it had obtained a complete record.  The corporation
expects that such authority ultimately will be granted.
 
     At its meeting in December 1998, the INTELSAT Board of Governors continued
its discussions on transforming the remaining portion of INTELSAT from a treaty-
based, intergovernmental organization to a fully private company.  The INTELSAT
Board of Governors will continue this work at its meeting in March 1999.  It is
the corporation's objective to privatize the remaining portion of INTELSAT by
the end of 2001. The corporation, as a minority shareholder and the U.S.
Signatory to INTELSAT, lacks the ability to independently effect a restructuring
of INTELSAT.  The success of the corporation's efforts will depend on its
ability to achieve a consensus among other signatories and participating member

                                       37
<PAGE>
 
governments.  A two-thirds vote of the governments that are members of INTELSAT
would be necessary for approval of any final privatization proposal.

     In September 1998, the Inmarsat Assembly of Parties approved a plan to
transfer the operating assets of the current Inmarsat intergovernmental
organization to a new company.  Inmarsat is expected to become an independent
commercial company, based in the United Kingdom, in April 1999.  While the new
company initially would not be publicly traded, it is expected that it would
proceed with an initial public offering within approximately 24 months after its
creation.  Individual ownership in the new company would be capped at 15%,
although COMSAT's ownership in Inmarsat at the time of privatization would be
grandfathered. COMSAT's ownership of Inmarsat was 22.2% as of December 31, 1998.
COMSAT's voting rights, however, would be capped at 15% with respect to votes
against certain shareholder resolutions.  Prior to the public offering, owners
are expected to be able to trade shares, and strategic investors may invest up
to $500 million in equity in the new company.

     COMSAT signed the relevant Inmarsat restructuring agreements in February
1999.  As a result, upon the transfer of Inmarsat's assets to the new company,
COMSAT will be able to exercise its shareholder rights, as described in the
preceding paragraph, and will continue to provide its current mobile satellite
communications services using the satellites of the Inmarsat successor company.

     As with INTELSAT, COMSAT currently consolidates its shares of the accounts
of Inmarsat. At the time of Inmarsat's privatization, the corporation will begin
using the equity method of accounting for its 22.2% investment in the new
company.  Under the equity method, the corporation would include its
proportionate share of the new company's operating results as part of the
corporation's operating results. Currently, Inmarsat does not recognize income
taxes in its financial results.  The successor company to Inmarsat will be
subject to income taxation in the jurisdiction in which it operates, the United
Kingdom. In 1998 and prior years, the corporation reported its proportionate
share of Inmarsat's operating results in revenues, operating expenses and other
income (expense).  As a result of the privatization of Inmarsat, the corporation
expects to report in 1999 its share of Inmarsat's operating results, net of U.K.
taxes, in other income (expense).  The corporation does not anticipate that its
use of the equity method of accounting for Inmarsat's results will affect its
net operating results.

     The following table illustrates the effect of adoption of the equity method
of accounting for the corporation's investment in Inmarsat on the corporation's
consolidated balance sheet.  The "As Reported" column reflects summary
historical financial information for the corporation as of December 31, 1998.
The "Proforma" column reflects similar summary unaudited proforma financial
information assuming the equity method had been adopted as of December 31, 1998.
The proforma information reflected is based upon the historical portion of
Inmarsat's financial information included in the corporation's consolidated
balance sheet as of December 31, 1998.  In preparing the proforma consolidated
balance sheet, the corporation's share of Inmarsat's assets and liabilities were
removed from the respective financial captions (e.g., property and equipment or
long-term debt) and reclassified as an investment in Inmarsat in the
consolidated balance sheet.  The proforma financial data is intended for
informational and illustrative purposes only and should not be viewed as
indicative of the future financial condition of the corporation on a
consolidated basis.

                                       38
<PAGE>
 
<TABLE>
<CAPTION>
In millions (Unaudited)
As of December 31, 1998                       As Reported            Proforma
- -------------------------------------------------------------------------------
<S>                                          <C>                   <C>      
Assets
     Current assets                           $     199             $     199
     Property and equipment                       1,210                   954
     Investments                                    249                   434
     Other                                          133                   133
                                              ---------             ---------  
       Total                                  $   1,791             $   1,720
                                              =========             =========
 
Liabilities and Stockholders' Equity
     Current liabilities                      $     141             $     137
     Long-term debt                                 447                   380
     Non-current liabilities                        344                   344
     Preferred securities issued by subsidiary      200                   200
     Stockholders' equity                           659                   659
                                              ---------             ---------   
       Total                                  $   1,791             $   1,720
                                              =========             =========
</TABLE>

Regulatory and Legislative Developments

     On April 24, 1998, the FCC granted the corporation's petition for
reclassification as a non-dominant common carrier in markets that currently
represent over 90% of CWS's revenues for INTELSAT services.  For those markets,
rate-of-return regulation was lifted immediately.  On February 9, 1999, the FCC
eliminated COMSAT's remaining rate-of-return regulation along thin routes in
favor of COMSAT's incentive-based pricing plan.  That plan will lower prices for
customers on thin routes and, at the same time, ease the regulatory burden on
the corporation in connection with its INTELSAT business. The FCC also adopted a
procedure for reclassifying thin routes as competition increases to make them
eligible for non-dominant treatment. The FCC's April 24, 1998 non-dominant order
also granted the corporation's request to file tariffs for thick-route services
on one day's notice with a presumption of lawfulness; tariffs for thin-route
services must be filed on 14 days' notice but require only minimal cost support.
The non-dominant order also granted the corporation's request for the
elimination of the CWS structural separation requirements and gave CWS authority
to enter the earth station market on an unseparated and non-dominant basis.

     On October 28, 1998, the FCC issued a separate notice of proposed
rulemaking that looks toward enabling users to have direct access to the
INTELSAT system, which would end COMSAT's status as the exclusive provider of
INTELSAT services in the United States.  In the direct access notice, the FCC
tentatively concluded, among other things, that it lacks the statutory authority
to impose Level 4 direct access (by which users could invest and acquire an
ownership interest in INTELSAT) but does have the authority to require Level 3
direct access (by which users could contract directly with INTELSAT for capacity
and bypass COMSAT).  The FCC sought comments on its tentative conclusion that it
would serve the public interest to mandate Level 3 direct access.  The
corporation filed comments contesting the basis for the FCC's proposed action.
The imposition of direct access could have a substantial adverse impact on the
corporation's financial condition and results of operations.  The corporation,
however, does not believe that the FCC has the current authority to grant direct
access under the Satellite Act and would vigorously contest the exercise of such
authority by the FCC.

                                       39
<PAGE>
 
     In October 1998, Congress passed, and the President subsequently signed,
the International Anti-Bribery Act of 1998.  The act provides that as of May 1,
1999, an international organization providing commercial satellite services will
not be accorded immunity from suit or legal process in connection with its
provision of such service, except as required by international agreements to
which the United States is a party that are so designated by the President.  The
Act requires the President to designate those agreements which are subject to
the exception and directs the President to take all appropriate actions to
reduce or eliminate all privileges and immunities that are not preserved by
designation.  The corporation opposed prior versions of this legislation but
supported it in the form ultimately passed by Congress.  The corporation does
not believe that enactment of this legislation will have a material effect on
its business, because (i) Inmarsat is expected to be privatized before May 1,
1999, and (ii) the President is expected to designate the INTELSAT Headquarters
Agreement an international agreement to which the United States is a party,
thereby requiring the United States to continue to afford INTELSAT immunity from
suit and legal process under the Act. The President has since delegated this
designation authority to the Secretary of State.

     On February 4, 1999, Senator Conrad Burns, Chairman of the Senate Commerce
Subcommittee on Communications, introduced the Open-market Reorganization for
the Betterment of International Telecommunications (Orbit) Act (S. 376).  COMSAT
believes that S. 376, on the whole, represents a constructive approach to the
privatization of INTELSAT and regulation of the corporation. Significantly, S.
376 would repeal the ownership restrictions on COMSAT stock upon enactment and
eliminate other outdated provisions in the Satellite Act.  The bill would not
interfere with the ongoing privatization of Inmarsat, which is expected to be
completed in April 1999.  The corporation does have concerns with some
provisions of the bill, including the 2002 target for full INTELSAT
privatization and a requirement that the President withdraw the U.S. from this
international organization if this privatization goal is not achieved.  Although
the corporation believes privatization of INTELSAT will be completed rapidly,
United States withdrawal from INTELSAT in 2002, if privatization is not
completed, would have a substantial adverse effect on the corporation's
financial condition and results of operations.

     The House of Representatives is also expected to consider satellite
privatization issues this year, most likely in the form of legislation being
prepared by Representative Tom Bliley, Chairman of the House Committee on
Commerce.  At this time, Representative Bliley's timetable for revising and re-
introducing his satellite bill passed by the House in the last Congress, which
was entitled Communications Satellite Competition and Privatization Act of 1998
(H.R. 1872), is unclear.  The corporation opposed H.R. 1872 because it contained
provisions that, in the view of the corporation's management, would adversely
affect the corporation's results of operations and the value of its
shareholders' investments in the INTELSAT and Inmarsat satellite systems. The
Clinton Administration opposed H.R. 1872 in testimony before the Senate Commerce
Committee late last year.
 
World Systems
 
     CWS continues to be well positioned through its long-term agreements with
major international carriers to provide cost-competitive services for bulk usage
beyond the year 2000.  In addition, CWS expects revenue growth from the
provision of services in emerging markets, including the Internet, international
VSAT, Asynchronous Transfer Mode (ATM) and Link One technology.  CWS also
expects to face increasing competition over the longer term from existing
competitors and new market entrants (including New Skies).

                                       40
<PAGE>
 
     INTELSAT currently has five INTELSAT IX satellites on order.  It is
expected that they will be launched during 2000 to 2002.  During 1998, INTELSAT
successfully completed the placement in orbit of the remaining two INTELSAT VIII
satellites.  Two of the six INTELSAT VIII satellites were a part of the transfer
of satellites to New Skies.  The new INTELSAT VIII series satellites offer
higher-power C-band capabilities to address various markets.

Mobile Communications
 
     CMC plans to continue to expand its service offerings and value-added
products to meet anticipated growth in customers' needs.  The increasing numbers
of digital terminals with improved operating efficiency and reduced service
charges are expected to make possible traffic growth in land mobile, small
commercial and pleasure boat, and business traveler markets.  CMC expects to
continue to face increasing competition from existing Inmarsat service
providers, other wireless communications services (including C-band), low earth
orbit satellite systems (such as Iridium) and other potential market entrants.

COMSAT International

     CI operates an integrated group of telecommunications companies that are
engaged principally in providing individualized digital network solutions to
business clients and carriers in selected emerging markets.  CI also plans to
develop prospective international telecommunications opportunities that are
consistent with its digital networking strategy.  In this regard, CI will
continue to target those rapidly growing markets where a significant number of
CI's existing or targeted clients are located (or in which they intend to
locate).
 
     On January 12, 1999, in response to increasing capital flight, the
Brazilian government widened the controlled trading band on its currency, the
Real. This created an initial devaluation of over 8% compared to the U.S.
Dollar. As support for the currency continued to diminish, it was apparent that
the Brazilian government needed to allow a "free-float," which occurred shortly
thereafter. As a result, the Brazilian Real was devalued over 40% compared to
the U.S. Dollar, and is no longer tied to a fixed trading range. It is expected
that the continued instability of the Real, as well as the current economic
climate within Brazil, will negatively impact growth and financial performance
during 1999 in CI's operation in Brazil. In 1998, COMSAT Brazil was CI's largest
operating company, accounting for approximately 40% of CI's revenues. In
addition, Brazil's problems could have the potential for a "spill-over" effect
into other Latin American markets in which CI has operations.
 
     CI faces certain operational risks inherent to the countries in which it
operates.  These risks are typical of emerging markets and include changes in
government regulations and licensing requirements; tariffs, taxes, sanctions and
other trade barriers; exchange controls; bureaucratic impediments; political,
social and economic instability; inflation, devaluation, interest rate and
exchange rate fluctuations.  There can be no assurance that the current economic
difficulties faced in Asia, Russia, Brazil and elsewhere, or any future economic
difficulties, or any other risks enumerated above or otherwise, will not
adversely impact CI's existing or prospective customers, thereby affecting CI's
ability to generate revenues or otherwise having a material adverse affect on
CI's financial results and condition.

                                       41
<PAGE>
 
Year 2000 Issue (Year 2000 Readiness Disclosure)

     The year 2000 issue is the result of existing computer programs that were
written using two digits rather than four digits to define the applicable year
(i.e., "98" for 1998). Certain of the corporation's computer programs that have
- -----                                                                          
date-sensitive software may not operate properly when the last two digits become
"00," as will occur on January 1, 2000. To the extent that this situation
exists, there is the potential for system failure or miscalculations, which
could cause a disruption of operations. The problem is not limited to computer
programs, as some of the corporation's computer and other operational equipment
that have date-sensitive processors may not be able to process dates after
December 31, 1999.

     In the second half of 1996, the corporation initiated a program to identify
and properly address issues associated with the year 2000 problem in order to
avoid interruption to the corporation's operations at the turn of the century.
Each of the operating segments of the corporation, as well as the administrative
functions, has completed the inventory and assessment phase of the year 2000
implementation plan and is currently implementing plans to remediate the non-
compliant systems identified during these first two phases.  The corporation
presently believes that such changes to the corporation's key computer and other
operational systems and equipment will be completed and tested by the end of the
third quarter of 1999.

     The corporation's current estimate is that it will cost approximately $8
million prior to January 1, 2000 to modify its in-house management information
systems, customer products and other systems and equipment affected by the year
2000 issue.  Of this amount, the corporation has spent $2.3 million, or
approximately 30% of the projected amount, through December 31, 1998. Year 2000
modifications and replacements are based on management's current expectations
and assumptions, which were derived using assumptions of future events,
including the continued availability of resources and the reliability of third-
party modification plans.  Future events that might cause material differences
in management's current expectations and assumptions include, but are not
limited to, the availability and cost of personnel with appropriate skills, the
ability to locate and correct all relevant computer code, reliance on third
parties and similar uncertainties.

     While the corporation is devoting substantial resources to its own year
2000 compliance effort, COMSAT, as well as other international
telecommunications carriers, will be dependent, in part, on foreign and other
third-party telecommunications carriers being year 2000 compliant. The financial
impact on CWS and CMC of foreign or third-party telecommunications carriers
failing to meet the year 2000 challenge would be realized in either of two ways:
loss of revenue due to the inability to complete the up-link or down-link
transmissions to or from a satellite and/or loss of the corporation's share of
INTELSAT and Inmarsat revenues.  In recognition of the financial exposure
resulting from this dependency on foreign and third-party telecommunications
carriers, the corporation has undertaken, as part of its year 2000 efforts, an
analysis of the year 2000 compliance efforts of these telecommunications
carriers. In addition to this analysis, the corporation is also utilizing the
results of efforts undertaken by the International Telecommunication Union
(ITU).  The corporation plans to develop contingency plans to deal with this
issue depending on the results of its analysis and the year 2000 readiness
status of individual telecommunications carriers.

     CWS derives in excess of 90% of its revenues under long-term contracts.
Almost all of these revenues are dependent upon termination with a foreign
telecommunication carrier.  Even though these long-term contracts are not
subject to termination as a result of the year 2000 issue, a significant portion

                                       42
<PAGE>
 
of the expected future CWS revenues and COMSAT's share of INTELSAT revenues is
generated from services between the United States and areas of the world that
may be subject to service interruptions resulting from year 2000 readiness
issues. In addition, CMC derives a significant portion of its revenues from
services either originating or terminating outside of the United States. If the
originating or terminating carrier is unable to initiate or terminate a call,
CMC, directly and through its share of Inmarsat revenues, would be adversely
affected by reduced revenues.  It is not possible for the corporation to
accurately quantify the amount, if any, of these exposures at this time.
 
     CI and the Labs rely on third-party vendor-provided and vendor-supported
systems to provide products and services to their customers. CI and the Labs
have sought, but have not yet received, final certification regarding year 2000
compliance from all of their third-party vendors.  If it became necessary, a
compliant product provided by a different supplier would be utilized to replace
a non-compliant product.

                    ANALYSIS OF CONSOLIDATED BALANCE SHEETS

Assets

     The corporation's total assets at December 31, 1998 were $1.8 billion, as
compared to $1.9 billion at December 31, 1997.  Current assets at the end of
1998 were $199 million, $119 million lower than December 31, 1997.  The declines
in both current and total assets were primarily related to the decrease of $130
million associated with the net assets of discontinued operations, offset in
part by the increase in cash and cash equivalents of $25 million.

     Property and equipment, net of depreciation, decreased $150 million during
1998, predominantly as the result of the transfer of satellites from INTELSAT to
New Skies.  See Note 6 to the financial statements.  New Skies property has been
reclassified to investments.  Property and equipment additions amounted to $225
million for 1998.  The increase in property and equipment was primarily related
to additions related to CWS's share of INTELSAT's satellite program and
investment in new communications property and equipment at CI.

     Investments increased $158 million during 1998, of which $143 million is
related to the transfer of satellites from INTELSAT to New Skies.

Liabilities

     The corporation's total liabilities decreased during 1998 by $177 million.
This was primarily the result of a decrease in commercial paper of $150 million.
The corporation used the proceeds from the sale of CRSI to reduce short-term
debt.  See Note 3 to the financial statements.
 
 

                                       43
<PAGE>
 
            ANALYSIS OF CASH FLOWS, LIQUIDITY AND CAPITAL RESOURCES

Cash Flows

     Cash from operating activities for 1998 was $323 million, compared to $169
million in 1997. In terms of continuing operations, cash from operating
activities was $220 million, or $14 million better than 1997.  CWS and CMC
generated the majority of the corporation's cash from continuing operations.
Cash provided from discontinued operations in 1998 was $103 million, which
primarily reflects proceeds related to the sale of CRSI.  During 1998, the
corporation made interest payments, net of amounts capitalized, of $37 million
and received income tax refunds of $2 million.

     During 1998, the corporation used $166 million in investing activities, a
25% decrease as compared to 1997.  The 1998 purchases of property and equipment
occurred primarily in CWS and CI, as the corporation continued to make capital
investments equal to its share of INTELSAT's satellite programs and purchased
communications property and equipment predominantly in CI's Latin American
companies.  The corporation expects to make additional investments in property
and equipment in 1999 at approximately the same level as 1998.

     Net cash used in financing activities during 1998 was $132 million, as
compared to net cash provided in 1997 of $50 million. During 1998, proceeds from
the sale of CRSI contributed significantly to the $150 million reduction in
short-term debt. The corporation paid dividends of $0.05 per share for each
quarter of 1998.
 
Liquidity and Capital Resources

     The corporation's working capital at December 31, 1998 was $58 million, an
increase of $37 million from December 31, 1997.  The increase in working capital
during 1998 was primarily the result of a decrease in commercial paper of $150
million and an increase in cash of $25 million, partially offset by the
reduction in net assets of discontinued operations of $130 million from the sale
of CRSI. The corporation reduced short-term debt primarily with the proceeds
from the sale of CRSI.  See Note 3 to the financial statements.  Cash from
operating activities in 1999 will be used to fund growth and to finance working
capital needs.

     The corporation has access to short-term and long-term financing at
favorable rates. The corporation's current long-term debt ratings are A- from
Standard and Poor's and A3 from Moody's. The corporation's current commercial
paper ratings are A2 from Standard and Poor's and P2 from Moody's. Following the
announcement of the Merger Agreement with Lockheed Martin, both Standard and
Poor's and Moody's placed their ratings on the corporation's long-term debt
under review for possible downgrades.  The downgrades would take effect as a
result of merging the corporation with a lower-rated parent company.  The
ratings for commercial paper are not under review at this time.  The current
ratings on the Monthly Income Preferred Securities issued by COMSAT Capital I,
L.P. are BBB from Standard and Poor's and A3 from Moody's.
 
     The corporation's $200 million commercial paper program had no borrowings
outstanding at December 31, 1998.  A $200 million credit agreement, expiring at
the end of 1999, backs up the corporation's commercial paper program.   This
credit agreement has a one-year option to extend its term 

                                       44
<PAGE>
 
to December 31, 2000. The corporation had $36 million remaining under a $100
million medium-term note program at December 31, 1998. The medium-term note
program is part of a $200 million debt securities shelf registration program
initiated in 1994.

     The corporation's capital structure and debt-financing activities are
regulated by the FCC. The corporation is required to submit a capitalization
plan to the FCC for review annually. Under the currently approved FCC
guidelines, the corporation is subject to a limit of $200 million in short-term
debt, a maximum long-term debt to total capital ratio of 45% and an interest
coverage ratio of 2.3 to 1.  The corporation was in compliance with the
guidelines at December 31, 1998, with a long-term debt to total capital ratio of
40.4%, no short-term debt outstanding other than $15 million of current
maturities of long-term debt, and an interest coverage ratio of 2.7 to 1.  If
the corporation were to fail to satisfy one or more of the FCC guidelines, the
corporation would be required to seek advance FCC approval of future financing
activities on a case-by-case basis.

                                       45
<PAGE>
 
Item 7a:  Quantitative and Qualitative Disclosures About Market Risk

     The corporation does not hold or issue derivative financial instruments.
The corporation finances its operations and manages its interest rates through a
combination of its short-term commercial paper, fixed-rate long-term debt and
Monthly Income Preferred Securities (MIPS) issued by a subsidiary.  The MIPS pay
a fixed dividend.  Borrowings under the corporation's short-term commercial
paper program will expose the corporation's operating results to changes in
short-term rates.  At December 31, 1998, no commercial paper was outstanding.

     As of December 31, 1998, the fair value of the corporation's fixed-rate,
long-term debt was $414,632,000.  Assuming a 10% increase in interest rates, the
fair value of the corporation's fixed-rate, long-term debt would be
$407,016,000.  Likewise, assuming a 10% decrease in interest rates, the fair
value of the corporation's fixed-rate, long-term debt would be $422,452,000.

     Inmarsat has entered into interest rate and foreign currency swap
arrangements to minimize the interest rate and foreign currency exchange
fluctuations related to its satellite financing obligations. Inmarsat borrowed
and is obligated to repay Pounds Sterling.  The Pounds Sterling borrowed were
swapped for U.S. Dollars with an agreement to exchange the Dollars for Pounds
Sterling in order to meet the future lease payments.  Inmarsat pays interest on
the Dollars at an average rate of 8.8%, and Inmarsat receives variable interest
on the Sterling amounts based on short-term LIBOR rates.  At December 31, 1998,
Inmarsat had $321,433,000 of swaps to be exchanged for L211,474,000 at various
dates through 2007.  The corporation's share of the estimated fair value of
these swaps is an unrealized gain of $8,214,000 at December 31, 1998.  The fair
value was estimated by computing the present value of the Dollar obligation
using current rates available for debt with similar terms and the current value
of the Sterling at year-end exchange rates.  Assuming a 10% increase in the
interest rates, the estimated unrealized gain would increase by $1,797,000.
Assuming a  10% decrease in the interest rates, the estimated unrealized gain
would decrease by $1,869,000.

     CI conducts its operations primarily through majority-owned and wholly-
owned subsidiaries.  The corporation has financed CI's subsidiaries through
capital contributions.  CI's largest subsidiaries utilize the local currency as
their functional currency.  Therefore, fluctuations in exchange rates relative
to the U.S. Dollar, primarily those related to the Brazilian Real, are recorded
as cumulative translation adjustments as a component of stockholders' equity.
Fluctuations in exchange rates relative to the U.S. Dollar have not had a
material impact on the corporation's cash flows or results of operations.

                                       46
<PAGE>
 
Item 8:   Financial Statements and Supplementary Data



REPORT OF INDEPENDENT AUDITORS



To the Shareholders of
COMSAT Corporation:

We have audited the accompanying consolidated balance sheets of COMSAT
Corporation and its subsidiaries as of December 31, 1998 and 1997, and the
related consolidated statements of income, stockholders' equity and cash flow
for each of the three years in the period ended December 31, 1998. Our audit
also included the financial statement schedule listed in the index at Item
14(a)2.  These financial statements and the financial statement schedule are the
responsibility of the corporation's management. Our responsibility is to express
an opinion on these financial statements and the financial statement schedule
based on our audits.

We conducted our audits in accordance with generally accepted auditing
standards.  Those standards require that we plan and perform the audit to obtain
reasonable assurance about whether the financial statements are free of material
misstatement.  An audit includes examining, on a test basis, evidence supporting
the amounts and disclosures in the financial statements.  An audit also includes
assessing the accounting principles used and significant estimates made by
management, as well as evaluating the overall financial statement presentation.
We believe that our audits provide a reasonable basis for our opinion.
 
In our opinion such consolidated financial statements present fairly, in all
material respects, the financial position of the corporation and its
subsidiaries at December 31, 1998 and 1997, and the results of their operations
and their cash flows for each of the three years in the period ended December
31, 1998, in conformity with generally accepted accounting principles.  Also, in
our opinion, such financial statement schedule, when considered in relation to
the basic consolidated financial statements taken as a whole, presents fairly in
all material respects, the information set forth therein.



Deloitte & Touche LLP
Washington, D.C.
February 18, 1999

                                       47
<PAGE>
 
                      COMSAT CORPORATION AND SUBSIDIARIES
                         CONSOLIDATED INCOME STATEMENTS
              For the Years Ended December 31, 1998, 1997 and 1996

<TABLE>
<CAPTION>
In thousands, except per share amounts                                1998       1997       1996
- --------------------------------------------------------------------------------------------------
<S>                                                                 <C>        <C>        <C>
Revenues                                                            $616,469   $562,651   $545,100
                                                                  ----------   --------   --------
Operating expenses:                                                             
  Cost of services                                                   284,053    263,934    247,120
  Depreciation and amortization                                      219,883    184,206    155,296
  Research and development                                             7,914      9,296     11,518
  General and administrative                                          25,592     23,247     23,941
  Impairment of long-lived assets                                     14,000          -          -
  Merger costs                                                         5,525          -          -
                                                                  ----------   --------   --------
Total operating expenses                                             556,967    480,683    437,875
                                                                  ----------   --------   --------
 
Operating income                                                      59,502     81,968    107,225
 
Other income (expense), net                                           12,518      4,245     (7,409)
Interest costs                                                       (44,502)   (51,426)   (50,455)
Interest capitalized                                                   4,690      9,394     15,760
                                                                  ----------   --------   --------
 
Income from continuing operations before taxes and
 extraordinary item                                                   32,208     44,181     65,121
 
Income tax expense                                                     5,791     15,613     28,924
                                                                  ----------   --------   --------
 
Income from continuing operations before extraordinary item           26,417     28,568     36,197
 
Discontinued operations, net of tax                                        -    (89,068)   (27,575)
                                                                  ----------   --------   --------
 
Income (loss) before extraordinary item                               26,417    (60,500)     8,622
 
Extraordinary loss from early extinguishment of debt, net of tax           -     (3,946)         -
                                                                  ----------   --------   --------
 
Net income (loss)                                                   $ 26,417   $(64,446)  $  8,622
                                                                  ==========   ========   ========
 
Earnings (loss) per common share - basic:
  Income from continuing operations before extraordinary item       $   0.51   $   0.58   $   0.76
  Discontinued operations                                                  -      (1.82)     (0.58)
  Extraordinary loss                                                       -      (0.08)         -
                                                                  ----------   --------   --------
  Net income (loss)                                                 $   0.51   $  (1.32)  $   0.18
                                                                  ==========   ========   ========
 
Earnings (loss) per common share - assuming dilution:
  Income from continuing operations before extraordinary item       $   0.50   $   0.57   $   0.74
  Discontinued operations                                                  -      (1.78)     (0.56)
  Extraordinary loss                                                       -      (0.08)         -
                                                                  ----------   --------   --------
  Net income (loss)                                                 $   0.50   $  (1.29)  $   0.18
                                                                  ==========   ========   ========
</TABLE>


The accompanying notes are an integral part of these financial statements.

                                       48
<PAGE>
 
                      COMSAT CORPORATION AND SUBSIDIARIES
                          CONSOLIDATED BALANCE SHEETS
                           December 31, 1998 and 1997

<TABLE>
<CAPTION>
In thousands                                                                   1998            1997
- ------------------------------------------------------------------------------------------------------
ASSETS
- ------
<S>                                                                       <C>             <C>
Current assets:
  Cash and cash equivalents                                                 $   30,795      $    5,757
  Receivables                                                                  131,052         147,621
  Deferred income taxes                                                          7,911           7,469
  Other                                                                         16,243          14,918
  Net assets of discontinued operations                                         12,964         142,484
                                                                            ----------    ------------
  Total current assets                                                         198,965         318,249
                                                                            ----------    ------------
 
Property and equipment                                                       1,209,462       1,359,293
Investments                                                                    249,064          91,543
Other assets                                                                   133,307         125,690
                                                                            ----------    ------------
  Total assets                                                              $1,790,798      $1,894,775
                                                                            ==========    ============
 
LIABILITIES AND STOCKHOLDERS' EQUITY
- ------------------------------------
Current liabilities:
  Current maturities of long-term debt                                      $   14,962      $   13,785
  Commercial paper                                                                   -         149,506
  Accounts payable and accrued liabilities                                      88,297          89,772
  Due to related parties                                                        30,424          34,664
  Other                                                                          7,119           8,919
                                                                            ----------    ------------
  Total current liabilities                                                    140,802         296,646
                                                                            ----------    ------------
 
Long-term debt                                                                 446,832         461,960
Deferred income taxes                                                          127,351         112,226
Deferred investment tax credits                                                  6,158           9,523
Accrued post-retirement benefit costs                                           48,923          49,246
Other long-term liabilities                                                    161,692         178,903
Commitments and contingencies (notes 10, 11 & 15)                                    -               -
Preferred securities issued by subsidiary                                      200,000         200,000
 
Stockholders' equity:
  Common stock, without par value, 100,000 shares authorized,                 
   52,713 shares issued in 1998 and 50,197 in 1997                             430,537         366,901
  Preferred stock, 5,000 shares authorized, no shares issued or outstanding
  Retained earnings                                                            242,809         226,785
  Treasury stock, at cost, 80 shares in 1998 and 141 in 1997                    (3,109)         (1,758)
  Unearned compensation                                                         (4,652)         (4,739)
  Accumulated other comprehensive loss                                          (6,545)           (918)
                                                                            ----------    ------------
  Total stockholders' equity                                                   659,040         586,271
                                                                            ----------    ------------
  Total liabilities and stockholders' equity                                $1,790,798      $1,894,775
                                                                            ==========    ============
</TABLE>

The accompanying notes are an integral part of these financial statements.

                                       49
<PAGE>
                       COMSAT CORPORATION AND SUBSIDIARIES
                       CONSOLIDATED CASH FLOW STATEMENTS
              For the Years Ended December 31, 1998, 1997 and 1996
<TABLE>
<CAPTION>
In thousands                                                             1998        1997        1996
- -------------------------------------------------------------------------------------------------------
<S>                                                                   <C>         <C>         <C>
Operating activities:
Net income (loss)                                                     $  26,417   $ (64,446)  $   8,622
Adjustments to reconcile net income (loss) to net cash provided by
  continuing operations:
  Depreciation and amortization                                         219,883     184,206     155,296
  Impairment of long-lived assets                                        14,000           -           -
  Loss from discontinued operations                                           -      89,068      27,575
  Gain on sale of investments                                           (14,635)     (1,987)     (2,722)
  Gain on sale of land                                                        -      (7,261)          -
  Extraordinary loss from early extinguishment of debt                        -       3,946           -
Changes in assets and liabilities:
  Receivables and other current assets                                   (6,890)      3,953     (12,539)
  Current liabilities                                                    21,441      (4,709)     34,935
  Non-current liabilities                                               (38,516)      1,665      15,770
Other                                                                    (1,749)      1,165       4,814
                                                                    -----------   ---------   ---------
Net cash provided by continuing operations                              219,951     205,600     231,751
Net cash provided (used) by discontinued operations                     102,769     (36,865)    (35,009)
                                                                    -----------   ---------   ---------
Net cash provided by operating activities                               322,720     168,735     196,742
                                                                    -----------   ---------   ---------
 
Investing activities:
Purchase of property and equipment                                     (187,838)   (254,291)   (267,279)
Investments in unconsolidated businesses                                 (6,202)    (19,950)    (59,923)
Proceeds from sale of land                                                    -       9,293           -
Proceeds from note on sale of investments                                     -      19,097           -
Proceeds from sale of investments                                        19,871       9,060      26,076
Satellite insurance proceeds                                              8,024           -      54,443
Decrease (increase) in INTELSAT ownership                                  (689)     23,232      (1,238)
Decrease in Inmarsat ownership                                            5,999         213       5,746
Other                                                                    (5,113)     (7,704)      8,328
                                                                    -----------   ---------   ---------
Net cash used in investing activities                                  (165,948)   (221,050)   (233,847)
                                                                    -----------   ---------   ---------
Financing activities:
Net short-term borrowings (repayments)                                 (149,506)    131,513      17,993
Repayments against company-owned life insurance policies                    (64)     (3,962)    (51,443)
Common stock issued                                                      46,453      20,398      13,837
Repayment of long-term debt                                             (13,760)   (114,903)     (9,848)
Payment of satellite performance incentives                              (4,464)          -           -
Cash dividends paid                                                     (10,393)    (16,975)    (37,698)
Proceeds from Clarksburg financing                                            -      34,342           -
                                                                    -----------   ---------   ---------
Net cash provided (used) by financing activities                       (131,734)     50,413     (67,159)
                                                                    -----------   ---------   ---------
 
Net increase (decrease) in cash and cash equivalents                     25,038      (1,902)   (104,264)
Cash and cash equivalents, January 1                                      5,757       7,659     111,923
                                                                    -----------   ---------   ---------
Cash and cash equivalents, December 31                                $  30,795   $   5,757   $   7,659
                                                                    ===========   =========   =========
 
Supplemental cash flow information:
  Interest paid, net of amount capitalized                            $  36,807   $  39,732   $  29,519
  Income taxes paid (refunded)                                           (1,676)     11,404       1,945
    Non-cash property additions:
        Inmarsat satellites                                               2,493       5,403       5,602
        Satellite performance incentives                                 34,397           -           -
  Distribution of Ascent Entertainment Group, Inc. shares                     -     194,633           -
</TABLE>
The accompanying notes are an integral part of these financial statements.

                                       50
<PAGE>
                       COMSAT CORPORATION AND SUBSIDIARIES
           STATEMENTS OF CHANGES IN CONSOLIDATED STOCKHOLDERS' EQUITY
              For the Years Ended December 31, 1998, 1997 and 1996
<TABLE>
<CAPTION>
                                                                                                          Accumulated
                                                                                                             Other
                                   Shares    Shares      Common    Treasury    Retained     Unearned     Comprehensive
          In thousands             Issued  Outstanding   Stock      Stock      Earnings   Compensation   Income (loss)      Total
- -----------------------------------------------------------------------------------------------------------------------------------
<S>                                <C>     <C>          <C>       <C>         <C>         <C>            <C>             <C>
Balance at December 31, 1995       48,612       47,755  $324,074    $(9,020)  $ 533,238        $(5,484)       $ (3,375)    $839,433
- -----------------------------------------------------------------------------------------------------------------------------------
Comprehensive income:
    Net income                                                                    8,622                                       8,622
    Unrealized gain on                                                                                           
     securities (net of tax of
     $3,916)                                                                                                     7,118        7,118
    Foreign currency translation                                                                                 
     (net of tax of $0)                                                                                            924          924
    Minimum pension liability                                                                                      
     (net of tax of $223)                                                                                          383          383
                                                                                                                           ---------
    Total comprehensive income                                                                                               17,047
Cash dividends                                                                  (37,698)                                    (37,698)
Stock awards and options, 401(k)
 and employee
    stock purchase plan               398          986    12,862      6,014                        468                       19,344
Other                                  80           80     3,755                 (1,323)         1,259                        3,691
- -----------------------------------------------------------------------------------------------------------------------------------
Balance at December 31, 1996       49,090       48,821   340,691     (3,006)    502,839         (3,757)          5,050      841,817
- -----------------------------------------------------------------------------------------------------------------------------------
Comprehensive loss:
    Net loss                                                                    (64,446)                                    (64,446)
    Unrealized loss on                                                                                          
     securities (net of tax
     benefit
        of $2,997)                                                                                              (5,411)      (5,411)
    Foreign currency translation                                                                                
     (net of tax of $0)                                                                                         (1,515)      (1,515)
    Minimum pension liability                                                                                      
     (net of tax of $553)                                                                                          958          958
                                                                                                                           ---------
    Total comprehensive loss                                                                                                (70,414)
Cash dividends                                                                  (16,975)                                    (16,975)
Distribution of Ascent
 Entertainment                                                                 
  Group Inc. shares                                                            (194,633)         
Stock awards and options, 401(k)
 and employee
    stock purchase plan             1,027        1,155    24,296      1,248                       (982)                      24,562
Other                                  80           80     1,914                                                              1,914
- -----------------------------------------------------------------------------------------------------------------------------------
Balance at December 31, 1997       50,197       50,056   366,901     (1,758)    226,785         (4,739)           (918)     586,271
- -----------------------------------------------------------------------------------------------------------------------------------
Comprehensive income:
    Net income                                                                   26,417                                      26,417
    Unrealized gain on                                                                                          
     securities (net of tax of
     $5,985)                                                                                                    11,072       11,072
    Foreign currency translation                                                                               
     (net of tax of $3,158)                                                                                    (14,380)     (14,380)
    Minimum pension liability
     (net of tax benefit                                                                                        
       of $1,414)                                                                                               (2,319)      (2,319)
                                                                                                                           ---------
    Total comprehensive income                                                                                               20,790
Cash dividends                                                                  (10,393)                                    (10,393)
Stock awards and options, 401(k)
 and employee
    stock purchase plan             2,474        2,535    62,232     (1,351)                        87                       60,968
Other                                  42           42     1,404                                                              1,404
- -----------------------------------------------------------------------------------------------------------------------------------
Balance at December 31, 1998       52,713       52,633  $430,537    $(3,109)  $ 242,809        $(4,652)       $ (6,545)    $659,040
===================================================================================================================================
</TABLE>
The accompanying notes are an integral part of these financial statements.

                                       51
<PAGE>
 
                      COMSAT CORPORATION AND SUBSIDIARIES
                   NOTES TO CONSOLIDATED FINANCIAL STATEMENTS
              For the Years Ended December 31, 1998, 1997 and 1996


1.   SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

     Principles of Consolidation.  Accounts of COMSAT Corporation and its
     majority-owned subsidiaries (COMSAT or the corporation) have been
     consolidated.  Significant intercompany transactions have been eliminated.

     The corporation has consolidated its shares of the accounts of the
     International Telecommunications Satellite Organization (INTELSAT) and the
     International Mobile Satellite Organization (Inmarsat).  The corporation's
     ownership interests in INTELSAT and Inmarsat are based primarily on the
     corporation's usage of these systems.  As of December 31, 1998, the
     corporation owned 18.0% of INTELSAT and 22.2% of Inmarsat.

     Use of Estimates.  The preparation of financial statements in conformity
     with generally accepted accounting principles requires estimates and
     assumptions that directly affect the amounts of assets and liabilities and
     disclosure of contingent assets and liabilities at the date of the
     financial statements and the reported amounts of revenues and expenses
     during the reporting period. Actual results may differ from those
     estimates.  Estimates are used in determining the loss on disposal of
     discontinued operations and in accounting for long-term contracts,
     allowance for doubtful accounts, depreciation and amortization, employee
     benefit plans, taxes, litigation, and contingencies.

     Revenue Recognition.  Revenue from satellite services is recognized over
     the period during which the satellite services are provided.  Revenue from
     long-term product, system integration and related services contracts is
     accounted for using the percentage-of-completion (cost-to-cost) method.
     Revenue from other services is recorded as services are provided.

     Income Taxes and Investment Tax Credits.  The provision for income taxes
     includes taxes currently payable and those deferred because of differences
     between the financial statement and tax bases of assets and liabilities.
     The corporation has earned investment tax credits on certain INTELSAT and
     Inmarsat satellite costs.  These tax credits have been deferred and are
     being recognized as reductions to the tax provision over the estimated
     service lives of the related assets.

     Evaluation of Long-Lived Assets.  In accordance with Statement of Financial
     Accounting Standards (SFAS) No. 121, "Accounting for the Impairment of
     Long-Lived Assets and for Long-Lived Assets to be Disposed of," the
     corporation evaluates the potential impairment of long-lived assets,
     including goodwill, based upon projections of undiscounted cash flows
     whenever events or changes in circumstances indicate that the carrying
     amount of an asset may not be fully recoverable.  Management believes no
     material impairment of these assets exists at December 31, 1998.

                                       52
<PAGE>
 
     Marketable Securities.  The corporation's marketable securities are
     categorized as available-for-sale securities, as defined in SFAS No. 115,
     "Accounting for Certain Investments in Debt and Equity Securities."
     Unrealized holding gains and losses are reflected, net of tax, as a
     separate component of accumulated other comprehensive income (loss) until
     realized.  For the purpose of computing realized gains and losses, cost is
     identified on a specific identification basis.

     Other Assets.  The cash surrender values of life insurance policies (net of
     loans) totaling $97,529,000 and $86,597,000 at December 31, 1998 and 1997,
     respectively, are included in "Other assets."  "Other income (expense),
     net" on the income statement includes $3,185,000, $3,379,000 and $3,351,000
     from the increases in the cash surrender values of these policies in 1998,
     1997 and 1996, respectively.
 
     Foreign Currency Translation. Financial statements of international
     subsidiaries are translated into U.S. dollars using the exchange rate at
     each balance sheet date for assets and liabilities and a weighted average
     exchange rate for each period for revenues, expenses, gains and losses.
     Where the local currency is the functional currency, translation
     adjustments are recorded as a separate component of stockholders' equity.
     Where the U.S. dollar is the functional currency, translation adjustments
     are recorded in the income statement.

     Stock-Based Compensation.  The corporation  accounts for employee stock-
     based compensation using the intrinsic value method prescribed in
     Accounting Principles Board Opinion No. 25, "Accounting for Stock Issued to
     Employees," and related interpretations. Accordingly, compensation costs
     for stock options are measured as the excess, if any, of the quoted market
     price of the corporation's stock at the date of the grant over the amount
     an employee must pay to acquire the stock.

     Cash Flow Information.  The corporation considers highly liquid investments
     with a maturity of three months or less at the time of purchase to be cash
     equivalents.

     Statement Presentation.  Certain prior period amounts have been
     reclassified to conform with the current year's presentation.

     New Accounting Pronouncements.  In June 1998, the Financial Accounting
     Standards Board issued SFAS No. 133, "Accounting for Derivative Instruments
     and Hedging Activities."  The statement requires companies to recognize all
     derivatives as either assets or liabilities, with the instruments measured
     at fair value.  The accounting for changes in fair value and gains or
     losses depends on the intended use of the derivative and its resulting
     designation.  The statement is effective for fiscal years beginning after
     June 15, 1999.  The corporation will adopt SFAS No. 133 in the first
     quarter of 2000.  The corporation is evaluating the effect that
     implementation of SFAS No. 133 will have on its consolidated financial
     statements.

                                       53
<PAGE>
 
2.   AGREEMENT AND PLAN OF MERGER WITH LOCKHEED MARTIN CORPORATION

     On September 18, 1998, COMSAT entered into an Agreement and Plan of Merger
     (the Merger Agreement) with Lockheed Martin Corporation (Lockheed Martin)
     and Deneb Corporation (Acquisition Sub), a wholly-owned subsidiary of
     Lockheed Martin.  Under the terms of the Merger Agreement, Lockheed Martin
     has agreed to acquire all of the outstanding common stock, no par value, of
     COMSAT (the COMSAT Common Stock) in a two-step transaction.

     On September 25, 1998, a wholly-owned subsidiary of Lockheed Martin,
     Regulus, LLC (Purchaser), initiated a tender offer to purchase up to 49%
     (subject to certain adjustments) of the COMSAT Common Stock at a price of
     $45.50 per share in cash.  The tender offer is being made pursuant to the
     Merger Agreement upon the terms and subject to the conditions set forth in
     the Purchaser's Offer to Purchase, dated September 25, 1998 (the Offer to
     Purchase), and the related Letter of Transmittal (which, together with the
     Offer to Purchase, constitute the Offer).

     Certain significant conditions to the consummation of the Offer include:
     (i) there being validly tendered and not withdrawn prior to the expiration
     date of the Offer at least one-third of the outstanding shares of COMSAT
     Common Stock; (ii) the approval by COMSAT shareholders of the Merger  and
     the Merger Agreement; and (iii) the receipt of all required regulatory
     consents and approvals, including the Purchaser having been authorized by
     the Federal Communications Commission (FCC) to acquire up to 49% of the
     COMSAT Common Stock and expiration of all waiting periods under applicable
     antitrust laws.  The Purchaser's obligation to consummate the Offer also is
     subject to there not being any fact or circumstance that would reasonably
     be expected to have a Material Adverse Effect (as defined in the Merger
     Agreement) on COMSAT or a decline in the Standard & Poor's 500 Index of at
     least 27% from date of the Merger Agreement through specified measurement
     dates.

     The Merger Agreement also provides that, as soon as practical after
     consummation of the Offer and the satisfaction or waiver of the conditions
     set forth therein, COMSAT will be merged with Acquisition Sub (the Merger).
     In the Merger, each share of COMSAT Common Stock that is issued and
     outstanding immediately prior to the effective time of the Merger (other
     than shares of COMSAT Common Stock held by COMSAT, Purchaser or Lockheed
     Martin and dissenting shares, if any) will be converted into the right to
     receive, as adjusted, one share of common stock, par value $1.00 per share,
     of Lockheed Martin.  The exchange ratio in the merger remains subject to
     further adjustment in the event of certain changes in the capitalization of
     Lockheed Martin.

     Certain significant conditions to the consummation of the Merger include:
     (i) the consummation of the Offer, (ii) the amendment of the Communications
     Satellite Act of 1962 (the Satellite Act), and  (iii) the receipt of the
     approvals of the FCC and other governmental authorities required for the
     consummation of the Merger.  In addition, the obligations of Lockheed
     Martin and Acquisition Sub to consummate the Merger are subject to there
     not being any fact or circumstance that would reasonably be expected to
     have a Significant Adverse Effect (as defined in the Merger Agreement).

                                       54
<PAGE>
 
     In connection with the execution of the Merger Agreement, the parties
     entered into certain ancillary agreements dated as of September 18, 1998.
     COMSAT entered into a Shareholders Agreement with Lockheed Martin (the
     Shareholders Agreement), pursuant to which, upon the consummation of the
     Offer, COMSAT will take all actions necessary to cause the three
     individuals selected by Lockheed Martin to be elected to the Board of
     Directors of COMSAT and appointed to certain committees of the Board of
     Directors of COMSAT.  Pursuant to the Shareholders Agreement, COMSAT agreed
     not to amend or repeal the provisions of its bylaws that permit any three
     directors to call a special meeting of the Board of Directors or otherwise
     amend its Articles of Incorporation or bylaws in a manner that would
     adversely affect the rights of Lockheed Martin under the Shareholders
     Agreement or the Registration Rights Agreement (described below).  The
     Shareholders Agreement also provides that, in the event that the Merger is
     not consummated, COMSAT will cause its Board of Directors to amend COMSAT's
     Articles of Incorporation to eliminate the transfer restrictions contained
     in Section 5.03(c) thereof and to recommend such amendment to the
     shareholders of COMSAT for their approval.  The Shareholders Agreement
     contains other restrictions on Lockheed Martin with respect to its
     ownership of COMSAT Common Stock.

     In addition, COMSAT and Lockheed Martin entered into the Registration
     Rights Agreement dated as of September 18, 1998 (the Registration Rights
     Agreement), pursuant to which, assuming that the Purchaser acquired shares
     of COMSAT Common Stock in the Offer and that the Merger is not consummated,
     Lockheed Martin has certain demand and piggy-back registration rights to
     cause COMSAT to prepare and file registration statements under the
     Securities Act of 1933, as amended, to register shares of COMSAT Common
     Stock held by Lockheed Martin.

     In order to facilitate consummation of the Offer and the Merger, COMSAT
     also entered into a Carrier Acquisition Agreement with Lockheed Martin, the
     Purchaser and COMSAT Government Systems, Inc. (CGSI), a wholly-owned
     subsidiary of COMSAT, pursuant to which CGSI will be merged with and into
     Purchaser  as soon as practical following the satisfaction or waiver of the
     conditions set forth in the Carrier Acquisition Agreement, or on such other
     date as the parties may agree, but in all events prior to the consummation
     of the Offer.  In the Carrier Acquisition, the Purchaser will acquire the
     common carrier telecommunications business of CGSI.

     In connection with the execution of the Merger Agreement, COMSAT adopted
     the Retention Bonus Plan.  The Retention Bonus Plan generally provides
     retention bonuses to certain key employees who remain employed by COMSAT
     (or incur a termination of employment, as defined) through specified dates
     subsequent to September 18, 1998.  Merger costs include compensation
     expense associated with the Retention Bonus Plan, investment banking fees
     and fees for other professional services incurred in 1998.

3.   DISCONTINUED OPERATIONS

     The corporation began accounting for Ascent Entertainment Group, Inc.
     (Ascent), its former entertainment subsidiary, and substantially all of the
     assets and operations of COMSAT RSI, Inc. (CRSI), its former manufacturing
     subsidiary, as discontinued operations in the second quarter of 1997.

                                       55
<PAGE>
 
     The income (loss) from discontinued operations, net of tax, for Ascent and
     CRSI for the two years ended December 31, 1997, is summarized below:

<TABLE>
<CAPTION>
     In thousands      1997       1996        
     ------------    --------- ---------    
     <S>             <C>        <C>            
     Ascent          $(29,068)  $(28,148)         
     CRSI             (60,000)       573         
                     ---------  --------             
     Total           $(89,068)  $(27,575)             
                     =========  ========           
</TABLE>                                       

     Ascent Entertainment Group, Inc.
     --------------------------------

     The corporation distributed its 80.67% interest in Ascent through a tax-
     free dividend to shareholders on June 27, 1997.  COMSAT shareholders of
     record on June 19, 1997 received 0.4888 of a share of Ascent common stock
     for each share of COMSAT common stock owned. The tax-free dividend of
     $194,633,000 was recorded as a reduction of COMSAT's consolidated retained
     earnings.

     Prior to being accounted for as a discontinued operation, Ascent reported
     revenues of $177,481,000 and $258,120,000 in 1997 and 1996, respectively.
     Ascent's loss from operations was $17,779,000 (net of a $5,047,000 tax
     benefit) in 1997 and $28,148,000 (net of a $10,637,000 tax benefit) in
     1996.  The loss on disposal of Ascent in 1997 was $11,289,000 (including a
     tax expense of $2,194,000).

     COMSAT RSI, Inc.
     ----------------

     On February 25, 1998, the corporation sold substantially all of the assets
     of CRSI Acquisition, Inc., d/b/a COMSAT RSI Jefa Wireless Systems (JEFA), a
     wholly-owned subsidiary of CRSI engaged in the wireless communications
     integration and intelligent transportation systems business, in a separate
     transaction.  Pursuant to the sale agreement, the corporation assigned to
     the buyer its rights in certain contracts and made a payment of $4,663,000
     to the purchaser, net of a working capital adjustment at closing.

     On June 25, 1998, the corporation completed the sale of substantially all
     of CRSI to a subsidiary of TBG Industries, Inc. for cash proceeds of
     $111,864,000, after adjusting for changes in inter-company loans and
     advances.

     In connection with the sale of CRSI and JEFA, the corporation and
     respective purchasers agreed to indemnify the other against certain losses.
     In the case of the CRSI sale, the corporation's indemnification obligations
     are generally limited to losses incurred in excess of an agreed threshold
     amount ($6,700,000) and are capped at a maximum agreed threshold amount
     ($28,000,000) in respect of claims made within an agreed survival period
     (generally, approximately two years).  In certain instances, however, the
     corporation's indemnification obligations are not subject to those
     limitations.

     Certain of CRSI's assets were excluded from the sale, including
     Electromechanical Systems, Inc. (EMS) and CRSI's 53% ownership interest in
     Plexsys International Corporation (Plexsys). EMS's revenues and income were
     not material to the corporation's consolidated operating results. 

                                       56
<PAGE>
 
     Plexsys ceased doing business on July 1, 1998. The corporation has written-
     off its investment in Plexsys and certain amounts owed to it by Plexsys.
     Such amounts were included in the corporation's 1997 loss from discontinued
     operations. COMSAT also retained and is completing a long-term construction
     contract for a radio astronomy telescope in Green Bank, West Virginia (the
     Green Bank contract). The corporation also has retained a claim against the
     prime contractor to recover $29,000,000 in costs incurred in performing the
     Green Bank contract, which are in excess of the original contract value.
     The prime contractor has filed a counterclaim seeking $12,900,000 million
     in damages for delay. The claim and counterclaim are currently in
     arbitration. There can be no assurance that the corporation will be
     successful in collecting all or any portion of this claim.

     The loss upon disposition of discontinued operations is based upon
     management's best estimates of the estimated costs to complete the Green
     Bank contract, the amount to be realized from the $29,000,000 Green Bank
     contract arbitration claim, potential indemnification claims and other
     costs related to the discontinued operations.  These estimates could change
     as additional costs are incurred to complete the Green Bank contract, upon
     resolution of the arbitration and upon resolution of other matters related
     to the CRSI discontinued operations.

     Prior to being accounted for as a discontinued operation, CRSI reported
     revenues of $121,291,000 in 1997 and $217,183,000 in 1996.  CRSI's income
     was $207,000 (net of a $46,000 tax expense) and $573,000 (net of a $232,000
     tax expense) in 1997 and 1996, respectively.  The estimated loss on
     disposal of CRSI in 1997 was $60,207,000 (net of a $19,926,000 tax
     benefit).

     The net assets of the CRSI discontinued operations totaled $142,484,000 at
     December 31, 1997 and included the following components: current assets of
     $181,456,000, non-current assets of $46,860,000, current liabilities of
     $33,212,000, non-current liabilities of $3,116,000 and a reserve for
     estimated loss on disposal of $49,504,000.
 
     The net assets of CRSI remaining at December 31, 1998 amount to $15,016,000
     and primarily consist of receivables on long-term contracts, fixed assets,
     current liabilities and the remaining reserve for estimated loss on
     disposal.  In addition to the net assets reported as current of
     $12,964,000, $2,052,000 is included in "Other assets."

                                       57
<PAGE>
 
4.    RECEIVABLES
      Receivables consisted of:

<TABLE>
<CAPTION>
      In thousands                                         1998       1997  
      ------------                                      ---------- ---------
      <S>                                                <C>        <C>     
      Commercial receivables                             $108,738   $120,320
      Receivables under long-term contracts:                                
        U.S. Government:                                                    
            Amounts billed                                  7,375      5,991
            Unbilled costs and accrued profits              9,505      9,577
        Commercial customers:                                               
            Amounts billed                                  5,177      4,197
            Unbilled costs and accrued profits              2,675        239
      Related party receivables                             4,836      6,422
      Other                                                 9,869     15,610
                                                         --------   --------
      Total                                               148,175    162,356
      Less allowance for doubtful accounts                (17,123)   (14,735)
                                                         --------   --------
      Net                                                $131,052   $147,621
                                                         ========   ======== 
</TABLE>

     Unbilled amounts represent accumulated costs and accrued profits that will
     be billed at future dates in accordance with contract terms and delivery
     schedules. The 1998 Unbilled receivables are expected to be billed within
     one year.

     In January 1997, the corporation sold its 19.66% interest in Philippine
     Global Communications, Inc. (PhilCom) for cash and a collaterized note
     receivable totaling $34,292,000.  At December 31, 1997, the remaining note
     receivable balance of $12,731,000 was to have been paid in two payments
     during 1998 and is recorded above in other receivables.  In the third
     quarter of 1998, the note was amended so that the balance would be paid in
     installments with interest through June 2000.  The corporation received a
     $1,000,000 principal payment in August 1998 and a $1,000,000 payment of
     principal and interest in January 1999.  At December 31, 1998, the note's
     current balance of $6,930,000 is included in "other receivables" in the
     table above, and the non-current portion of $4,524,000 is recorded in
     "Other assets."

                                       58
<PAGE>
 
5.    PROPERTY AND EQUIPMENT

      Property and equipment includes the corporation's shares of INTELSAT and
      Inmarsat property and equipment.

<TABLE>
<CAPTION>
      In thousands                                     1998        1997    
      ------------                                 -----------   ----------- 
      <S>                                          <C>           <C>           
      Property and equipment at cost:                                         
         Satellites                                $ 1,601,832   $ 1,695,352 
         Furniture, fixtures and equipment             737,915       595,812 
         Buildings and improvements                    107,772       108,635 
         Land                                            3,246         3,244 
                                                   -----------   ----------- 
         Total                                       2,450,765     2,403,043 
         Less accumulated depreciation              (1,298,336)   (1,161,242)
                                                   -----------   ----------- 
         Net property and equipment in service       1,152,429     1,241,801 
                                                                              
      Property and equipment under construction:                              
         INTELSAT satellites                            37,393        88,540 
         Inmarsat third-generation satellites                -         5,353 
         Other                                          19,640        23,599 
                                                   -----------   ----------- 
         Total                                     $ 1,209,462   $ 1,359,293 
                                                   ===========   ===========  
</TABLE>

     Satellites include construction costs, launch costs, direct development
     costs, insurance costs, satellite performance incentive payments and
     capitalized interest. Depreciation is calculated using the straight-line
     method over the estimated service life of each asset.  The service lives
     for property and equipment generally are: satellites, 10 to 13 years;
     furniture, fixtures and equipment, 3 to 15 years; buildings and
     improvements, 3 to 40 years.

     Change in Satellite Accounting Policies.  Effective January 1, 1998, the
     corporation changed its accounting policy with respect to the cost of
     satellites lost at launch or in orbit.  Such costs will be expensed in the
     period in which the satellite is lost at launch or experiences a total
     failure in orbit.  Previously, the cost of failed satellites was amortized
     over their original useful lives. Partial in-orbit failures will be
     evaluated for impairment according to the provisions of Statement of
     Financial Accounting Standards (SFAS) No. 121, "Accounting for the
     Impairment of Long-lived Assets to be Disposed of."  Also effective January
     1, 1998, the corporation changed its accounting policy with respect to
     satellite performance incentive payments paid to manufacturers to
     capitalize the net present value of such costs as a component of the cost
     of the satellite. Previously, certain of these payments were expensed as
     paid.  These changes did not have a material effect on the corporation's
     financial statements.

     Satellite Insurance Proceeds. The INTELSAT 801 satellite suffered damage
     during in-orbit testing following its launch in the first quarter of 1997.
     Although the satellite's operational capability has not been diminished,
     its depreciable life has been shortened from 10 years to 8 years.  Under
     the terms of its satellite insurance policy, the corporation received
     insurance proceeds of $8,024,000 in the third quarter of 1998 and,
     correspondingly, reduced the book value of the satellite.

                                       59
<PAGE>
 
     On February 14, 1996, the launch of the INTELSAT 708 satellite failed. The
     corporation's share of the satellite's cost was fully insured. Insurance
     proceeds totaling $54,443,000 were received in the second quarter of 1996.

     Sale of Land.  In September 1997, COMSAT sold its Clarksburg, Maryland
     office building and the surrounding land for $45,750,000 in an all-cash
     transaction.  A gain of $7,261,000 was recognized on the sale of land and
     is reported in "Other income (expense), net" on the income statement.  The
     corporation also entered into a 10-year lease agreement with the new owner
     to continue occupying the office building, which principally houses COMSAT
     Laboratories.  In addition to lease payments, the corporation is
     responsible for taxes, insurance and maintenance of the building.  The
     sale-leaseback of the office building has been accounted for as a financing
     due to COMSAT's continuing involvement as the lessor of floor space in the
     building to non-COMSAT tenants.  As a result, the historical cost of the
     building remains in property and will be depreciated over the 10-year lease
     term.

     A financing obligation of $36,219,000, representing the proceeds received
     for the building, was recorded at the time of sale.  This obligation is
     being amortized as the lease payments are made. The net present value at
     December 31, 1998 totals $33,612,000, of which $2,078,000 is reflected in
     other current liabilities and the remainder in other long-term liabilities.

     At December 31, 1998, the future lease payments pursuant to the sale-
     leaseback are $4,707,000 in 1999, $5,273,000 in 2000, $5,418,000 in 2001,
     $5,567,000 in 2002, $5,720,000 in 2003 and $22,869,000 thereafter.
 

6.   INVESTMENTS

     Investments as of December 31, 1998 and 1997 are as follows:

<TABLE>                                                 
<CAPTION>
                                                        Unrealized    
                                                          Holding     
     In thousands                               Cost       Gain      Total    
     -----------------------------------------------------------------------  
<S>                                            <C>       <C>         <C>       
                                                                              
                                                                              
     Available-for-sale equity securities:                                    
          ICO                                 $ 41,189     $ 1,239  $ 42,428  
          Other                                  6,376      18,444    24,820  
                                              --------     -------  --------  
          Total                                 47,565      19,683    67,248  
                                              --------     -------  --------  
     Cost investments:                                                        
          New Skies                            142,587           -   142,587  
          ICO                                   29,484           -    29,484  
          Other                                  9,298           -     9,298  
                                              --------     -------  --------  
          Total                                181,369           -   181,369  
     Equity investees                              447           -       447  
                                              --------     -------  --------  
     Total                                    $229,381     $19,683  $249,064  
                                              ========     =======  ========  
</TABLE>                                                                      

                                       60
<PAGE>
 
<TABLE> 
<CAPTION> 

     In thousands                             Cost      Gain        Total
     -----------------------------------------------------------------------
   <S>                                      <C>        <C>       <C> 
     1997
     ----
     Available-for-sale equity securities:    $ 10,583     $ 2,626  $ 13,209
                                              --------     -------  --------
     Cost investments:
          ICO                                   71,784           -    71,784
          Other                                  6,481           -     6,481
                                              --------     -------  --------
          Total                                 78,265           -    78,265
     Equity investees                               69           -        69
                                              --------     -------  --------
     Total                                    $ 88,917     $ 2,626  $ 91,543
                                              ========     =======  ========
</TABLE>
     
     New Skies.  Effective November 30, 1998, INTELSAT transferred five
     operational satellites, plus a sixth which is currently under construction,
     to New Skies Satellites N.V. (New Skies). New Skies is a commercial company
     which was created by INTELSAT in March 1998.
    
     As a result of INTELSAT's transfer of the satellites, plus working capital,
     the corporation has reclassified $146,826,000 from  property and equipment
     and $4,239,000 from liabilities to establish its $142,587,000 investment in
     New Skies.  The corporation owns 16.6% of New Skies and will account for
     this investment using the cost method.

     Had New Skies been formed as of January 1, 1998, and the satellites been
     transferred to New Skies at that time, the corporation's unaudited proforma
     consolidated revenues, operating income and net income for 1998 would have
     been $597,330,000, $56,713,000 and $24,868,000, respectively.

     ICO.  During 1998, ICO Global Communications (Holdings) Limited (ICO)
     conducted an initial public offering.  As a result, the corporation's
     direct investment in ICO is now treated as an available-for-sale equity
     security.  In addition, the corporation has an indirect investment in ICO
     through its ownership of Inmarsat.  Due to certain lock-up provisions
     associated with the initial public offering, 85% of the ICO shares held by
     Inmarsat did not qualify as a  marketable security at December 31, 1998;
     therefore, 85% of the corporation's share of Inmarsat's investment in ICO
     is presented as a cost investment and the balance is classified as
     available-for-sale.
 
     In December 1998, ICO paid the corporation $4,500,000 to settle a dispute
     between the two companies.  In exchange for this payment, the corporation
     transferred operation of ICO's Satellite Access Node facility in the United
     States back to ICO and waived the non-exclusive distribution rights it
     received under its 1995 stock subscription agreement with ICO.  Net of
     costs associated with transferring the facility, the corporation recognized
     income of $4,303,000 from the settlement.  This income is recorded in
     "Other income (expense), net" on the income statement.

     In December 1996, the corporation reduced its direct investment in ICO by
     selling 777,701 of its shares to other ICO shareholders for $29,941,000.
     The corporation recognized a gain of $2,722,000 that is included in "Other
     income (expense), net" on the income statement.

     Realized Gains (Losses).  The corporation realized gains of $14,635,000 and
     $1,987,000 from the sale of marketable equity securities during 1998 and
     1997, respectively.  The corporation recognized losses of $1,008,000 and
     $1,105,000 during 1997 and 1996, respectively, for a decline in value of a
     marketable equity security that was deemed other than temporary.  In 1998,

                                       61
<PAGE>
 
     the corporation wrote-off a $1,950,000 investment that was included in the
     "cost investments-other" category in the table above.  These amounts are
     reported in "Other income (expense), net" on the income statement.
 
7.   IMPAIRMENT OF LONG-LIVED ASSETS

     In the third quarter of 1998, the corporation recorded a non-cash
     impairment loss of $14,000,000 related to the write-down of the goodwill
     ($9,434,000) and plant and equipment ($4,566,000) of BelCom, COMSAT
     International's company operating in Russia and the Commonwealth of
     Independent States (CIS).  The impairment loss is reported in the
     International segment.

     In accordance with the corporation's accounting policy for evaluation of
     long-lived assets, the corporation evaluates its long-lived assets whenever
     events or circumstances indicate the carrying amount of an asset may not be
     fully recoverable.  Due to the worsening economic conditions in Russia and
     the CIS and BelCom's deteriorating performance, management determined that
     the corporation's investment in BelCom should be reduced.  The impairment
     loss was determined based on a discounted analysis of expected cash flows.

8.   DEBT

     The corporation's capital and debt-financing activities are regulated by
     the FCC.  The corporation is required to submit a capitalization plan to
     the FCC for review annually. Under existing FCC guidelines, the corporation
     is subject to a limit of $200,000,000 in short-term borrowings, a maximum
     long-term, debt-to-total-capital ratio of 45% and an interest coverage
     ratio, as defined, of 2.3 to 1.  At December 31, 1998, the corporation was
     in compliance with those guidelines.

     Long-Term Debt.  Long-term debt, including the corporation's share of
     INTELSAT and Inmarsat debt, at each year end consists of:

<TABLE>
<CAPTION>
     In thousands                                          1998       1997
     --------------------------------------------------  -------------------
     <S>                                                 <C>        <C>
     8.125% notes due 2004                               $ 70,475   $ 70,475
     8.95% notes due 2001                                  75,000     75,000
     6.75% INTELSAT Eurobonds due 2000                     26,980     26,932
     7.375% INTELSAT Eurobonds due 2002                    35,973     35,910
     8.375% INTELSAT Eurobonds due 2004                    35,973     35,910
     6.625% INTELSAT Asian bonds due 2004                  35,973     35,910
     8.125% INTELSAT Eurobonds due 2005                    35,973     35,910
     Inmarsat lease financing obligations                  82,135     96,504
     Medium-term notes, 7.7% - 8.66%, due 2006 - 2007      64,000     64,000
     Discounts on notes payable                              (688)      (806)
                                                         -------------------
     Total                                                461,794    475,745
     Less current maturities                              (14,962)   (13,785)
                                                         -------------------
     Total long-term debt                                $446,832   $461,960
                                                         ===================
</TABLE>

                                       62
<PAGE>
 
     The principal amount of debt (excluding the Inmarsat lease financing
     obligations) maturing over the next five years is $0 in 1999, $26,980,000
     in 2000, $74,988,000 in 2001, $35,973,000 in 2002 and $0 in 2003.

     Commercial Paper.  The corporation issues short-term commercial paper as
     needed with repayment terms of 90 days or less under a $200,000,000
     program.  The corporation had no borrowings at December 31, 1998.  At
     December 31, 1997, outstanding borrowings were $149,506,000 with a weighted
     average interest rate of 6.51%.

     Credit Facilities.  The corporation has a $200,000,000 revolving credit
     agreement, which expires in December 1999 and provides a backup source of
     credit to the commercial paper program.  The corporation has an option to
     extend this credit agreement to December 31, 2000.  There have been no
     borrowings under this agreement.

     Early Extinguishment of Debt.  The corporation repurchased $89,525,000 of
     its 8.125% notes and also $10,000,000 of its 7.7% medium-term notes with
     short-term debt in 1997.  The early extinguishment of debt resulted in an
     extraordinary loss of $6,231,000 ($3,946,000 net of tax).

     Inmarsat Lease Financing Obligations.  Inmarsat entered into capital lease
     agreements to finance the construction of its second- and third-generation
     satellites.  The corporation's share of these lease obligations is included
     in long-term debt.  Inmarsat has hedged its obligations through various
     foreign exchange transactions to minimize the effect of fluctuating
     interest and exchange rates (see Note 15).

     The corporation's share of the payments under these lease obligations for
     each of the next five years is $18,998,000 in 1999, $19,689,000 in 2000,
     $19,985,000 in 2001, $11,043,000 in 2002, $6,267,000 in 2003 and
     $20,529,000 thereafter.  These payments include interest totaling
     $14,376,000 and a current maturity of $14,962,000.

9.   MONTHLY INCOME PREFERRED SECURITIES

     In July 1995, COMSAT Capital I, L.P. (COMSAT Capital) issued $200,000,000
     of Monthly Income Preferred Securities (MIPS).  COMSAT Capital is a limited
     partnership formed for the sole purpose of issuing the MIPS and loaning the
     proceeds to COMSAT, the managing general partner.  The MIPS were issued at
     a par value of $25 per share, and dividends are payable monthly at an
     annual rate of 8.125%.  The MIPS are callable by the issuer after July 2000
     at par value.

     The proceeds of the MIPS were loaned to COMSAT under the terms of a 8.125%,
     30-year subordinated debenture agreement.  This agreement allows COMSAT to
     extend the maturity of the debentures until 2044, provided that COMSAT
     satisfies certain financial covenants.  The loan between the partnership
     and COMSAT has been eliminated in consolidation. The $200,000,000 of MIPS
     is shown on the corporation's consolidated balance sheet as "preferred
     securities issued by subsidiary."  The dividends on these securities are
     recorded as minority interest expense of $16,250,000, in "Other income
     (expense), net" on the income statement for each of the three years ended
     December 31, 1998.

                                       63
<PAGE>
 
10.  COMMITMENTS AND CONTINGENCIES

     Property and Equipment.  As of December 31, 1998, the corporation had
     commitments to acquire property and equipment totaling $187,431,000.  Of
     this total, $169,527,000 is payable over the next three years.  These
     commitments are related principally to the corporation's share of INTELSAT
     satellite acquisition programs.

     Leases.  The corporation leases its headquarters building from a
     partnership in which the corporation owns a 50% interest.  The initial term
     of the lease expires in 2008.  In addition to lease payments, the
     corporation is responsible for taxes, insurance and maintenance of the
     building.  The corporation also has leases of other property and equipment.
     Rental expense under operating leases was $7,579,000 in 1998, $5,367,000 in
     1997 and $5,179,000 in 1996. The future rental payments under operating
     leases are $9,402,000 in 1999, $7,087,000 in 2000, $5,867,000 in 2001,
     $5,408,000 in 2002, $5,251,000 in 2003 and $21,679,000 thereafter.

     Space Segment.  At December 31, 1998, the corporation's commitments for
     space segment capacity from New Skies and certain third parties are
     $26,608,000 in 1999, $19,468,000 in 2000, $18,516,000 in 2001, $15,942,000
     in 2002, $10,654,000 in 2003, and $32,903,000 thereafter.

     Government Contracts and Investigations.  The corporation and its
     subsidiaries are subject to, and are currently a party to, audits and
     investigations by various government agencies which oversee contract
     performance in connection with the corporation's contracts with the U.S.
     Government or which regulate the corporation's compliance with federal and
     state laws.  If the corporation is found liable for wrongdoing as a result
     of such an audit or investigation, the corporation could be fined or
     subjected to other punitive actions.  See Note 11 for a description of an
     investigation affecting Electromechanical Systems, Inc., a discontinued
     operations subsidiary of the corporation.

     In response to a communication from an agency of the federal government
     regarding the corporation's compliance with export control laws, the
     corporation made a disclosure with respect to certain of its export
     licensing activities.  In addition, the corporation has received a subpoena
     from a separate agency of the federal government requesting certain
     information in connection with a possible criminal investigation of the
     same matter.  The corporation cannot predict at this time whether or to
     what extent the government may seek sanctions for any possible violations
     of the export control laws and, therefore, cannot predict the ultimate
     outcome of this matter or estimate the amount of liability, if any, that
     could result from any civil or criminal sanctions the government may seek.
     There can be no assurances, however, that any such liability would not be
     material.

                                       64
<PAGE>
 
     Environmental Issues. The corporation reviews, on a quarterly basis, its
     estimates of costs of compliance with environmental laws and the cleanup of
     various sites, including sites for which governmental agencies have
     designated the corporation as a potentially responsible party. When it is
     probable that obligations have been incurred and where a minimum cost or a
     reasonable estimate of the cost of compliance or remediation can be
     determined, the applicable amount is accrued. Because of the uncertainties
     associated with environmental assessment and remediation activities, future
     expense to remediate currently identified sites could be higher than the
     liability currently accrued.

11.  REGULATORY ENVIRONMENT AND LITIGATION
 
     Regulatory Environment.  Under the Satellite Act, the International
     Maritime Satellite Act of 1978 (the Inmarsat Act) and the Communications
     Act of 1934, as amended (the Communications Act), COMSAT is subject to
     regulation by the FCC with respect to its capital and organizational
     structure, and with respect to its COMSAT World Systems (CWS) and COMSAT
     Mobile Communications (CMC) businesses.  FCC decisions and policies have
     had and will continue to have a significant impact on the corporation.  In
     addition, the telecommunications companies which the corporation operates
     in various developing countries are subject to regulation by the local
     regulatory bodies in those countries.  Because the regulatory environment
     in those countries is rapidly evolving as the local economies are
     developing, these companies face increasing business uncertainties that
     could have an adverse effect on their operations.

     In April 1998, the FCC granted the corporation's petition to be deregulated
     and reclassified CWS as a "non-dominant" telecommunications carrier in its
     major markets.  The FCC's decision eliminates rate-of-return restrictions,
     structural separation regulation and 14-day advance tariff notification in
     regard to approximately 90% of COMSAT's INTELSAT business.  It also allows
     CWS to integrate earth station and space segment services, requiring only
     that COMSAT list those offerings separately in tariff filings at the FCC.
     On February 9, 1999, the FCC further deregulated COMSAT by eliminating rate
     of return regulation on so-called "non-competitive thin routes" and
     occasional use "single carrier" markets.  In its place, the FCC adopted an
     incentive-based price policy for COMSAT's provision of INTELSAT services in
     these markets.  The FCC also adopted a procedure for reclassifying these
     markets as non-dominant as competition is introduced.

     On October 28, 1998, the FCC issued a separate notice of proposed
     rulemaking that looks toward enabling users to have direct access to the
     INTELSAT system, which would end COMSAT's status as the exclusive provider
     of INTELSAT services in the U.S.  In the direct access notice, the FCC
     tentatively concluded, among other things, that it lacks the statutory
     authority to impose Level 4 direct access (by which users could invest and
     acquire an ownership interest in INTELSAT), but does have the authority to
     require Level 3 direct access (by which users could contract directly with
     INTELSAT for capacity and bypass COMSAT).  The FCC sought comments on its
     tentative conclusion that it would serve the public interest to  mandate
     Level 3 direct access.  The corporation filed comments in this proceeding
     contesting the basis for the FCC's proposed action.

                                       65
<PAGE>
 
     Litigation. The corporation and its subsidiaries are a party to various
     lawsuits and arbitration proceedings and are subject to various claims and
     inquiries, which generally are incidental to the ordinary course of its
     business. See Note 3 for a description of an arbitration proceeding related
     to the Green Bank contract to which the corporation is a party. The outcome
     of legal proceedings cannot be predicted with certainty. Based on currently
     available information, however, management does not believe that the
     outcome of any matter which is pending or threatened, either individually
     or in the aggregate, will have a material adverse effect on the long-term
     consolidated financial condition of the corporation. Nevertheless, the
     outcome of such matters could materially affect consolidated results of
     operations in a given year or quarter.

     In January 1999, the U.S. Department of Justice announced that it had
     joined a lawsuit filed by former employees of Electromechanical Systems,
     Inc. (EMS), a wholly-owned subsidiary of the corporation, under the qui tam
     provisions of the Civil False Claims Act.  The corporation acquired EMS in
     1994 as part of the corporation's acquisition of Radiation Systems, Inc.
     The corporation began accounting for COMSAT RSI as a discontinued operation
     in 1997 and retained EMS when the corporation sold COMSAT RSI in 1998 (see
     Note 3).  The lawsuit names EMS, the corporation and several current and
     former EMS employees and seeks potential damages estimated at up to
     $40,000,000.  The Department of Justice is expected to file its own
     complaint in this matter and may then seek to stay the lawsuit pending the
     outcome of a separate criminal investigation into the same allegations that
     is currently being conducted by the U.S. Attorney's office in Tampa,
     Florida.  The corporation intends to vigorously defend this matter but
     cannot predict the ultimate outcome or estimate the amount of liability, if
     any, that could result from any civil or criminal sanctions the government
     may seek.  There can be no assurances, however, that any such liability
     would not be material.

12.  STOCKHOLDERS' EQUITY

     Comprehensive Income (Loss).  In 1998, the corporation adopted SFAS No.
     130, "Reporting Comprehensive Income."  The statement established rules for
     the reporting of comprehensive income and its components.  Comprehensive
     income consists of net income (loss), unrealized gain (loss) on securities,
     foreign currency translation and minimum pension liability adjustments and
     is presented in the Statements of Changes in Consolidated Stockholders'
     Equity.  The adoption of SFAS No. 130 had no impact on total stockholders'
     equity.  Prior years' financial statements have been reclassified to
     conform to the SFAS No. 130 requirements.

     The balance of the components of accumulated other comprehensive income
     (loss), net of tax, at December 31, 1998 and 1997 are as follows:

<TABLE>
<CAPTION>
     In thousands                       1998       1997            
     ------------                    ---------- --------         
     <S>                              <C>        <C>              
     Unrealized gain on securities    $ 12,779   $ 1,707          
     Foreign currency translation      (14,783)     (403)         
     Minimum pension liability          (4,541)   (2,222)         
                                      ---------  -------          
     Total                            $ (6,545)  $  (918)         
                                      =========  =======          
</TABLE>

                                       66
<PAGE>
 
     Effective January 1, 1998, the corporation no longer accounts for its
     Brazil subsidiary as highly inflationary.  Foreign currency translation
     adjustments are now recorded in "Accumulated other comprehensive loss."

     The unrealized gain on securities reported in the Statements of Changes in
     Consolidated Stockholders' Equity includes a  reclassification  adjustment
     of $9,513,000, net of tax, in 1998 related to a gain realized from the sale
     of marketable equity securities.

     Earnings Per Share.  The following reconciliation presents the calculation
     of the corporation's basic and diluted earnings per share amounts:

<TABLE>
<CAPTION>
     In thousands, except per share amounts        1998     1997     1996
     ----------------------------------------------------------------------
     <S>                                        <C>       <C>      <C> 
     Income from continuing operations before
           extraordinary item                     $26,417  $28,568  $36,197
                                                  =======  =======  =======
      
     Basic:
     Weighted average shares outstanding           51,673   48,924   47,870
                                                  =======  =======  =======
           Per share                              $  0.51  $  0.58  $  0.76
                                                  =======  =======  =======
      
     Assuming dilution:
           Weighted average shares outstanding     51,673   48,924   47,870
           Stock options                            1,415      766      647
           Restricted stock awards and unit           195      313      402
                                                  -------  -------  -------
           Total                                   53,283   50,003   48,919
                                                  =======  =======  =======
           Per share                              $  0.50  $  0.57  $  0.74
                                                  =======  =======  =======
</TABLE>
   
     Stock Incentive Plans.  The corporation has stock incentive plans that
     provide for the issuance of stock options, restricted stock awards, stock
     appreciation rights and restricted stock units.  A total of 7,169,000
     shares of common stock may be granted under the current plans.  As of
     December 31, 1998, 71,000 shares of the corporation's treasury stock and
     7,098,000 unissued common shares were reserved for these plans.  As of
     December 31, 1998, no stock appreciation rights were outstanding.

     Adjustments were made in 1997 to equitably increase the number of shares
     and decrease the exercise price for all outstanding stock options as a
     result of the tax-free spinoff of Ascent. Vested stock options held by
     Ascent employees generally expired 90 days after the date of the spinoff.
     Unvested stock options held by Ascent employees continue to vest as long as
     the employee is employed by Ascent and then expire 90 days after vesting.

     Adjustments were also made to increase the number of restricted stock
     awards and restricted stock units outstanding for the effect of the Ascent
     spinoff.

     Stock Options.  Under the current plans, the exercise price for stock
     options may not be less than the fair market value of the stock when
     granted.  Options generally vest over three years and expire after 10 to 15
     years.

 

                                       67
<PAGE>
 
     Stock option activity was as follows:

<TABLE>
<CAPTION>
     Options in thousands                     1998     1997     1996            
     --------------------                   -------- -------- -------         
     <S>                                    <C>       <C>      <C>            
     Outstanding at January 1                 5,152    4,478    4,415         
        Granted                                 997      655      899         
        Exercised                            (2,465)    (848)    (481)        
        Canceled                               (253)    (283)    (355)        
        Adjustment due to Ascent spinoff          -    1,150        -         
                                            --------  ------   ------         
     Outstanding at December 31               3,431    5,152    4,478         
     Exercisable at December 31               1,709    3,300    2,270         
     Average price                                                           
        Outstanding at January 1            $ 18.33   $22.20   $22.08         
        Granted                               31.14    25.01    19.44         
        Exercised                             18.91    18.26    17.24         
        Canceled                              20.75    18.68    20.37         
        Adjustment due to Ascent spinoff          -    17.84        -         
        Outstanding at December 31            21.46    18.33    22.20         
        Exercisable at December 31            17.79    18.92    23.00         
</TABLE>                        

     The weighted average fair value at date of grant for options granted during
     1998, 1997 and 1996 was $12.72, $6.89 and $5.59, respectively.  The fair
     value of options at date of grant was estimated using the Black-Scholes
     model assuming an expected option life of seven years and the following
     weighted average assumptions:

<TABLE>
<CAPTION>
     Per share          1998    1997    1996    
     ---------------------------------------    
     <S>               <C>     <C>     <C>      
     Dividend yield     0.84%   3.29%   3.37%           
     Interest rate      5.35%   6.47%   5.70%           
     Volatility        36.82%  37.21%  29.47%           
</TABLE>

     Stock options outstanding at December 31, 1998, are as follows:
 
<TABLE>
<CAPTION>
     In thousands, except per share amounts and years                                                           
     --------------------------------------------------------------------------------------------------                 
                                 Options Outstanding                          Options Exercisable                       
                        ----------------------------------------      ---------------------------------                 
                                            Weighted Average                                                            
                                       -------------------------                                                                
        Exercise Price     Number         Remaining      Exercise        Number        Weighted Average                 
           Range        Outstanding    Term in Years     Price        Exercisable      Exercise Price                   
     ----------------   -----------    -------------   ---------      -----------     ----------------                  
     <S>               <C>             <C>             <C>            <C>                  <C>                          
     $4.81 - $ 8.59         143             2.25         $ 6.82            143              $ 6.82                      
     10.94 -  18.85       1,101             6.63          15.58            720               15.67                      
     20.06 -  29.09       1,262             6.35          21.10            846               21.46                      
     30.13 -  38.78         925             9.18          31.23              -                   -                      
                        -----------                                   -----------                                       
     4.81  -  38.78       3,431             7.03          21.46          1,709               17.79                      
                        ===========                                   ===========                                       
</TABLE>

     Restricted Stock Awards.  Restricted stock awards are shares of stock that
     are subject to restrictions on their sale or transfer.  In 1998, 1997 and
     1996, 30,800, 152,470 and 66,000 "performance-based" restricted stock
     awards were granted, respectively.  The 1997 amount includes an adjustment
     of outstanding awards due to the Ascent spinoff.  Grantees have record
     ownership of the underlying securities; however, all such securities are
     subject to forfeiture at the end of a two-year performance period.  In
     addition to the two-year performance period, the awards are further subject
     to a three-year vesting schedule.  The weighted average fair value at 

                                       68
<PAGE>
 
     date of grant for restricted stock awards granted during 1998, 1997 and
     1996 was $30.81, $23.71 and $18.00 per share, respectively, which in each
     case was equal to the market value of the common stock at the date of
     grant.

     The expected cost of all grants is amortized over the performance and
     vesting period.  The expense for all outstanding grants was $1,071,000 in
     1998, $870,000 in 1997 and $1,296,000 in 1996.

     Restricted Stock Units.  Restricted stock units entitle the holder to
     receive a combination of stock and cash equal to the market price of common
     stock for each unit, when vested.  These units vest over three years.
     During 1998, 1997 and 1996, respectively, 36,850, 54,360 and 34,000
     restricted stock units were granted .  The 1997 amount includes an
     adjustment of outstanding units due to the Ascent spinoff.  The weighted
     average fair value for the units granted during 1998, 1997 and 1996 was
     $32.32, $25.50 and $18.99 per unit, respectively, which in each case was
     equal to the market value of the common stock at the date of grant.
     Partially vested restricted stock units outstanding totaled 80,036 at
     December 31, 1998 and 110,200 at December 31, 1997. The cost of these
     awards is amortized to expense over the three-year vesting period.  The
     expense in 1998, 1997 and 1996 was $1,012,000, $575,000 and $924,000,
     respectively.

     Employee Stock Purchase Plan.  Employees may purchase stock at a discount
     through the corporation's Employee Stock Purchase Plan.  The purchase price
     of the shares is the lower of 85% of the fair market value of the stock on
     the offering date, or 85% of the fair market value of the stock on the last
     business day of each month throughout the one-year offering period.  The
     purchase price on the respective offering dates for calendar years 1998,
     1997 and 1996, was $19.76, $21.36 (adjusted to $17.22 subsequent to the
     Ascent spinoff) and $16.04, respectively.

     There were 196,000 shares, 181,000 shares and 254,000 shares issued under
     this plan at weighted average prices of $19.76, $18.26 and $16.03 for the
     years ended December 31, 1998, 1997 and 1996, respectively.  As of December
     31, 1998, a total of 1,381,000 shares of the corporation's unissued common
     stock has been reserved for this plan.

     The weighted average fair value of the purchase rights granted pursuant to
     this plan in 1998, 1997 and 1996 was $5.66, $5.95 and $4.07, respectively.
     The fair value of each purchase right was estimated using the Black-Scholes
     model as of  January 1 of each year assuming each plan year consisted of 12
     one-month options and the following weighted average assumptions:

<TABLE>
<CAPTION>
     Per share          1998    1997    1996     
     ---------------------------------------     
     <S>               <C>     <C>     <C>               
     Dividend yield     0.84%   3.30%   3.89%            
     Interest rate      5.56%   5.39%   5.11%            
     Volatility        36.52%  35.79%  27.33%            
</TABLE>

                                       69
<PAGE>
 
     Proforma Disclosures. Had stock-based compensation cost for the
     corporation's stock incentive plans been determined based on the fair value
     at the grant dates consistent with SFAS No.123, the corporation's income
     from continuing operations before extraordinary item and per share amounts
     would have been as follows for each year:

<TABLE>
<CAPTION>
     In thousands, except per share amounts           1998     1997     1996        
     -------------------------------------------------------------------------   
     <S>                                             <C>      <C>      <C>          
     Income from continuing operations:                                             
          before extraordinary item                                                 
          As reported                                $26,417  $28,568  $36,197      
          Proforma                                    23,380   26,024   34,269      
     Earnings per common share - basic:                                             
          As reported                                $  0.51  $  0.58  $  0.76      
          Proforma                                      0.45     0.53     0.72      
     Earnings per common share-assuming dilution:                                   
          As reported                                $  0.50  $  0.57  $  0.74      
          Proforma                                      0.44     0.52     0.70      
</TABLE>

     The proforma effect on income from continuing operations before
     extraordinary item for such years is not representative of its effect for
     future years because it does not take into consideration proforma
     compensation expense related to grants made prior to 1995.

13.  PENSION AND OTHER BENEFIT PLANS

     Effective December 31, 1998, the corporation adopted SFAS No. 132,
     "Employer's Disclosures about Pensions and Other Post-retirement Benefits."
     The provisions of SFAS No. 132 revise employer's disclosures about pension
     and other post-retirement benefit plans but do not change the measurement
     or recognition of these plans.

     The corporation has a non-contributory, defined benefit pension plan for
     qualifying employees. Pension benefits are based on years of service and
     compensation prior to retirement.  The components of net pension expense
     (benefit) for each year are:

<TABLE>
<CAPTION>
     In thousands                                1998       1997      1996          
     ----------------------------------------------------------------------         
     <S>                                       <C>        <C>       <C>             
     Service cost                              $  2,401   $ 2,005   $ 2,590         
     Interest cost                                8,400     7,690     7,213         
     Expected return on plan assets             (10,158)   (9,039)   (8,520)        
     Amortization of transition asset            (1,195)   (1,208)   (1,208)        
     Amortization of prior service costs            382       386       386         
                                             ----------   -------   -------         
     Net periodic pension expense (benefit)    $   (170)  $  (166)  $   461         
                                             ==========   =======   =======         
</TABLE>

     The following tables show a reconciliation of the changes in the pension
     plan's benefit obligation and fair value of the plan assets as well as the
     funded status of the plan as of December 31, 1998 and 1997:

                                       70
<PAGE>
<TABLE>
<CAPTION>
     In thousands                                        1998       1997            
     ---------------------------------------------------------------------          
     <S>                                               <C>        <C>               
     Reconciliation of benefit obligation                                           
     Benefit obligation at January 1                   $119,826   $103,608          
     Service cost                                         2,401      2,005          
     Interest cost                                        8,400      7,690          
     Actuarial loss                                       8,654     10,618          
     Benefits paid from plan assets                      (4,498)    (4,095)         
                                                       --------   --------          
     Benefit obligation at December 31                 $134,783   $119,826          
                                                       ========   ========          
                                                                                    
     Reconciliation of fair value of plan assets                                    
     Fair value of plan assets at January 1            $150,874   $126,936          
     Actual return on plan assets                        21,229     28,033          
     Benefits paid from plan assets                      (4,498)    (4,095)         
                                                       --------   --------          
     Fair value of plan assets at December 31          $167,605   $150,874          
                                                       ========   ========          
                                                                                    
     Funded status                                                                  
     Funded status at December 31                      $ 32,822   $ 31,048          
     Unrecognized gain                                  (38,218)   (35,802)         
     Unrecognized prior service cost                      1,146      1,529          
     Unrecognized transition asset                            -     (1,195)         
                                                       --------    -------          
     Accrued pension liability                         $ (4,250)  $ (4,420)         
                                                       ========   ========          
                                                                                    
     Assumed discount rate                                 6.75%      7.00%         
     Assumed rate of compensation increase                 5.50%      5.00%         
     Expected rate of return on pension plan assets        9.50%      9.00%         
</TABLE>                                

     Supplemental Executive Retirement Plan.  The corporation's supplemental
     executive retirement plan is an unfunded defined benefit plan. The
     components of net pension expense under this plan for each year are:

<TABLE>
<CAPTION>
     In thousands                               1998    1997    1996         
     ---------------------------------------------------------------        
     <S>                                      <C>     <C>     <C>           
     Service cost                             $  324  $  278  $  491        
     Interest cost                             1,703   1,409   1,454        
     Amortization of transition obligation       266     266     266        
     Amortization of losses                      842     210     606        
                                            --------  ------  ------        
     Net periodic pension expense             $3,135  $2,163  $2,817        
                                            ========  ======  ======        
</TABLE>

     The following tables show a reconciliation of the changes in the
     supplemental plan's benefit obligation and fair value of the plan assets as
     well as the funded status of the plan as of December 31, 1998 and 1997:

<TABLE>
<CAPTION>
     In thousands                                         1998       1997
     ----------------------------------------------------------------------
     <S>                                                <C>        <C>
     Reconciliation of benefit obligation
     Benefit obligation at January 1                    $ 21,193   $ 22,136
     Service cost                                            324        278
     Interest cost                                         1,703      1,409
     Actuarial (gain) loss                                 4,895     (1,272)
     Benefits paid                                        (1,727)    (1,358)
                                                        --------   --------
     Benefit obligation at December 31                  $ 26,388   $ 21,193
                                                        ========   ========
</TABLE> 
                                       71
<PAGE>
<TABLE> 
<CAPTION> 
     In thousands                                           1998       1997
     -----------------------------------------------------------------------
<S>                                                 <C>           <C>       
     Reconciliation of fair value of plan assets
     Fair value of plan assets at January 1             $      0   $      0
     Employer contributions                                1,727      1,358
     Benefits paid                                        (1,727)    (1,358)
                                                        --------   --------
     Fair value of plan assets at December 31           $      0   $      0
                                                        ========   ========
      
     Funded status
     Funded (unfunded) status at December 31            $(26,388)  $(21,193)
     Unrecognized loss                                     8,816      4,763
     Unrecognized transition obligation                      798      1,064
     Additional minimum liability                         (8,042)    (4,575)
                                                        --------   --------
     Total accrued liability                            $(24,816)  $(19,941)
                                                        ========   ========
      
     Intangible asset                                   $    798   $  1,064
     Amount recognized in other comprehensive income    $  7,244   $  3,510
      
     Assumed discount rate                                  6.75%      7.00%
     Assumed rate of compensation increase                  5.50%      5.00%
</TABLE>

     401(k) Plan. The corporation has a 401(k) plan for qualifying employees. A
     portion of employee contributions is matched by the corporation with shares
     of its common stock. The number of shares contributed to the plan and the
     respective market values each year were as follows: 1998 - 68,000 shares
     ($2,186,000), 1997 - 108,000 shares ($2,433,000) and 1996 -140,000 shares
     ($3,035,000).

     Post-retirement Benefits.  The corporation provides health and life
     insurance benefits to qualifying retirees.  The expected cost of these
     benefits is recognized during the years in which employees render service.
     The components of net post-retirement benefit expense for each year are:

<TABLE>
<CAPTION>
     In thousands                             1998      1997      1996
     ------------------------------------------------------------------
     <S>                                    <C>       <C>       <C>
     Service cost                           $   895   $   666   $ 1,019
     Interest cost                            2,252     1,877     2,496
     Amortization of net gains               (1,841)   (2,360)   (1,219)
                                            -------   -------   -------
     Net post-retirement benefit expense    $ 1,306   $   183   $ 2,296
                                            =======   =======   =======
</TABLE>
     
     The following tables show a reconciliation of the changes in the post-
     retirement plan's obligation and fair value of the plan assets as well as
     the funded status of the plan as of December 31 for both years:

<TABLE>
<CAPTION> 
     In thousands                                     1998       1997
     ------------------------------------------------------------------
     <S>                                            <C>        <C>
     Reconciliation of benefit obligation
     Benefit obligation at January 1                $ 28,890   $ 29,460
     Service cost                                        895        666
     Interest cost                                     2,252      1,877
     Plan amendments                                    (573)         -
     Actuarial (gain) loss                             5,373     (1,753)
     Benefits paid                                    (1,628)    (1,360)
                                                    --------   --------
     Benefit obligation at December 31              $ 35,209   $ 28,890
                                                    ========   ========
</TABLE> 
                                       72
<PAGE>
 
<TABLE> 
<CAPTION> 
     In thousands                                       1998       1997
     -------------------------------------------------------------------
<S>                                             <C>          <C>    
     Reconciliation of fair value of plan assets
     Fair value of plan assets at January 1         $      0   $      0
     Employer contributions                            1,628      1,360
     Benefits paid                                    (1,628)    (1,360)
                                                    --------   -------- 
     Fair value of plan assets at December 31       $      0   $      0
                                                    ========   ======== 
     Funded status
     Funded (unfunded) status at December 31        $(35,209)  $(28,890)
     Unrecognized (gain) loss                         (1,455)    (6,829)
     Unrecognized gain from plan changes             (12,259)   (13,527)
                                                    --------   -------- 
     Accrued post-retirement benefit costs          $(48,923)  $(49,246)
                                                    ========   ======== 

     Assumed discount rate                              6.75%      7.00%
     Assumed rate of compensation increase              5.50%      5.00%
</TABLE>
     
     An 8.0% increase in health care costs was assumed for 1998 with the rate
     decreasing 0.5% each year to an ultimate rate of 5.5%.  A 1% change in the
     assumed health care cost trend rate would have the following impact on
     post-retirement benefit cost and obligation:

<TABLE>
<CAPTION>
                                                                    1% Change
                                                               ------------------
     In thousands                                              Increase  Decrease
     ----------------------------------------------------------------------------
     <S>                                                       <C>       <C>
     Effect on total service and interest cost component of
       post-retirement benefit cost                              $  431   $  (347)
                                                                 ======   ======= 
      
     Effect on the post-retirement benefit obligation            $4,376   $(3,484)
                                                                 ======   ======= 
     </TABLE>

14.  INCOME TAXES
     Income (loss) from continuing operations before taxes and extraordinary
     item consisted of:

<TABLE>
<CAPTION>
      In thousands      1998       1997      1996
     ---------------------------------------------
     <S>              <C>        <C>       <C>
     United States    $ 63,144   $47,927   $73,707
     Foreign           (30,936)   (3,746)   (8,586)
                      --------   -------   -------
     Total            $ 32,208   $44,181   $65,121
                      ========   =======   =======
     </TABLE>
     The components of income tax expense on continuing operations are:
<TABLE>
<CAPTION>
     In thousands                      1998      1997      1996
     ------------------------------------------------------------
     <S>                                <C>       <C>        <C>
     Federal:                           
         Current                        $ 6,914   $15,783   $22,910
         Deferred                         1,962    (2,162)   (1,076)
         Investment tax credits (net)    (1,687)   (1,837)   (1,844)
     State and local                     (2,369)    1,487     6,779
     Foreign                                971     2,342     2,155
                                        -------   -------   ------- 
     Total                              $ 5,791   $15,613   $28,924
                                        =======   =======   ======= 
</TABLE>
                                       73
<PAGE>
 
     The difference between income tax expense computed at the statutory Federal
     tax rate and the corporation's effective tax rate is:

<TABLE>
<CAPTION>
     In thousands                                             1998       1997      1996
     -----------------------------------------------------------------------------------
     <S>                                                    <C>        <C>       <C>
     Federal income taxes computed at the statutory rate    $ 11,273   $15,463   $22,792
     Foreign losses                                            5,389     3,654     4,335
     Investment tax credits (net)                             (1,688)   (1,837)   (1,844)
     Adjustment to estimated income tax accruals             (14,208)     (839)     (506)
     State income taxes, net of federal income taxes          (1,569)      972     4,408
     Life insurance (net)                                     (1,115)   (1,183)   (1,173)
     Other non-deductible costs                                1,403       433       156
     Merger costs                                              1,467         -         -
     Impairment loss                                           4,900         -         -
     Other                                                       (61)   (1,050)      756
                                                            --------   -------   -------
     Income tax expense                                     $  5,791   $15,613   $28,924
                                                          ==========   =======   =======
</TABLE>
     
     The current and net non-current components of deferred tax accounts as
     shown on the balance sheet at December 31, 1998 and 1997 are:
<TABLE>
<CAPTION>
     In thousands                             1998        1997
     -----------------------------------------------------------
     <S>                                   <C>         <C>
     Current deferred tax asset            $   7,911   $   7,469
     Non-current deferred tax liability     (127,351)   (112,226)
                                           ---------   --------- 
     Net liability                         $(119,440)  $(104,757)
                                           =========   ========= 
</TABLE>
     
     The deferred tax assets and liabilities at December 31, 1998 and 1997 are:
<TABLE>
<CAPTION>
     In thousands                          1998        1997
     ----------------------------------------------------------
     <S>                                <C>          <C>
     Assets:
       Post-retirement benefits           $  23,425   $  22,042
       Accrued expenses                      42,787      45,803
       NOL carryforward                       9,818           -
       Long-term contract revenues            6,876       7,946
       Foreign tax credit carryforward        3,159           -
       Alternative minimum tax credit        31,454      30,476
       Other                                  4,954       3,181
                                          ---------   --------- 
     Total deferred tax assets              122,473     109,448
                                          ---------   --------- 
      
     Liabilities:
       Property and equipment              (209,952)   (214,025)
       Unrealized gain on securities         (6,098)       (180)
       Foreign currency translation          (3,158)          -
       Basis in cost investment             (22,705)          -
                                          ---------    --------  
     Total deferred tax liabilities        (241,913)   (214,205)
                                          ---------    -------- 
      
     Net liability                        $(119,440)  $(104,757)
                                          =========   ========= 
</TABLE>
     The corporation favorably resolved a state tax audit for the years 1992-
     1996 that allowed the corporation to reverse previously accrued interest
     costs of $1,720,000 and state taxes of $2,238,000. After federal taxes, the
     interest and state tax benefit increased net income in 1998 by $2,573,000.

                                       74
<PAGE>
 
     In addition, the corporation reversed previously accrued interest costs of
     $2,456,000 and taxes of $15,100,000 for the years 1990-1994 related to
     certain federal tax matters. Events during the third quarter of 1998
     prompted the corporation to conclude that the amounts accrued were no
     longer required. The interest and tax benefit increased net income in 1998
     by $16,633,000.

     The Internal Revenue Service (IRS) has completed examinations of the
     federal income tax returns of the corporation through 1994. The corporation
     is contesting adjustments proposed by the IRS on the 1990 through 1994
     income tax returns. The corporation has also amended its returns and filed
     claims for refunds for 1979 through 1987, which the IRS has denied. In
     1996, the corporation filed suit in a U.S. District Court seeking the
     refunds which the IRS denied. The suit remains pending. In the opinion of
     the corporation, adequate provision has been made for income taxes for all
     periods through 1998.

15.  FINANCIAL INSTRUMENTS AND OFF-BALANCE-SHEET RISKS

     Inmarsat has entered into foreign currency contracts designed to minimize
     exposure to exchange rate fluctuations on fixed operating expenses
     denominated in British pounds sterling. At December 31, 1998, Inmarsat had
     several contracts maturing primarily in 1999 to purchase foreign currency
     for a total of $116,616,000. The corporation's share of the estimated fair
     value of these contracts, as determined by a bank, is an unrealized gain of
     approximately $886,000 at December 31, 1998.

     Inmarsat has entered into interest rate and foreign currency swap
     arrangements to minimize the exposure to interest rate and foreign currency
     exchange fluctuations related to its satellite financing obligations.
     Inmarsat borrowed and is obligated to repay Pounds Sterling. The Pounds
     Sterling borrowed were swapped for U.S. Dollars with an agreement to
     exchange the Dollars for Pounds Sterling in order to meet the future lease
     payments. Inmarsat pays interest on the Dollars at an average fixed rate of
     8.8%, and it receives variable interest on the Sterling amounts based on
     short-term LIBOR rates. The differential to be paid or received is accrued
     as interest rates change and is recognized over the life of the agreements.
     The currency swap arrangements have been designated as hedges, and any
     gains or losses are included in the measurement of the debt. The effect of
     these swaps is to change the sterling lease obligation into fixed-interest-
     rate Dollar debt. As of December 31, 1998, Inmarsat had $321,433,000 of
     swaps to be exchanged for (Pounds)211,474,000 at various dates through
     2007. Inmarsat is exposed to loss if one or more of the counter parties
     defaults. However, Inmarsat does not anticipate non-performance by the
     counter parties as all are major financial institutions. The corporation's
     share of the estimated fair value of these swaps is an unrealized gain of
     $8,214,000 at December 31, 1998. The fair value was estimated by computing
     the present value of the Dollar obligations using current rates available
     for issuance of debt with similar terms and the current value of the
     Sterling at year-end exchange rates.

     The fair value of long-term debt (excluding capitalized leases) shown below
     was estimated by obtaining a yield-adjusted price for each obligation from
     an investment banker. The fair value of the Monthly Income Preferred
     Securities was determined by using the quoted market price. The fair values
     of the corporation's other financial instruments are approximately equal to
     their carrying amounts. The carrying amount and fair value at each year end
     are as follows: 

                                       75
<PAGE>
 
<TABLE>
<CAPTION>
                                                   1998                1997
                                          ----------------------------------------
                                            Carrying    Fair    Carrying    Fair
     In thousands                            Amount    Value     Amount    Value
     -----------------------------------------------------------------------------
     <S>                                    <C>       <C>       <C>       <C>
     8.125% notes due 2004                  $ 70,475  $ 77,971  $ 70,475  $ 74,971
     8.95% notes due 2001                     75,000    80,525    75,000    80,123
     INTELSAT bonds                          170,872   183,974   170,572   180,425
     Medium-term notes                        64,000    72,162    64,000    69,035
     Monthly income preferred securities     200,000   203,000   200,000   204,000
</TABLE>


16.  BUSINESS SEGMENT INFORMATION

     The corporation adopted SFAS No. 131, "Disclosures About Segments of an
     Enterprise and Related Information," in 1998, which changes the way the
     corporation reports information about its operating segments. The
     information for 1997 and 1996 has been restated in order to conform to the
     1998 presentation.

     The corporation reports operating results and financial data in four
     segments: COMSAT World Systems (CWS), COMSAT Mobile Communications (CMC),
     International and Laboratories. CWS provides voice, data, Internet, video
     and audio communications services between the U.S. and other countries
     using the global satellite networks of INTELSAT and New Skies. CWS also
     includes the operating results of COMSAT Government Systems, Inc., COMSAT
     Digital Teleport, Inc. and COMSAT General Corporation, which provide
     various satellite and ground segment services to commercial and government
     customers. CMC provides voice, data, fax, telex and information services
     for ships, aircraft and land mobile applications throughout the world using
     the Inmarsat satellite system. Together, the CWS and CMC operating segments
     represent the corporation's Satellite Services business unit.

     International consists of activities undertaken by the corporation in its
     COMSAT International (CI) business. CI operates an integrated group of
     telecommunications companies that are engaged principally in providing
     individualized digital network solutions to business clients and carriers
     in high-growth emerging markets overseas.

     Laboratories (Labs) consists of activities undertaken by the corporation in
     its COMSAT Laboratories business, which provides technical consulting
     services and develops advanced communications technologies and products for
     satellite access and networking applications.

     The accounting policies of the operating segments are the same as those
     described in the summary of significant accounting policies. The
     corporation evaluates the performance of its operating segments based on
     income (loss) before income taxes and interest costs. Summarized financial
     information concerning the corporation's reportable segments is shown in
     the following tables. The "Other" column includes the elimination of
     intersegment revenues, corporate related items, and interest costs, net of
     amounts capitalized. Corporate assets, primarily consisting of short-term
     investments, net assets of discontinued operations, property and cash
     surrender value of life insurance policies, are reported in the "Other"
     column. The operating segments' income (loss) and corporate related amounts
     total the amount presented as income before taxes and extraordinary item in
     the consolidated income statements.

                                       76
<PAGE>
 
<TABLE>
<CAPTION>
                                          SATELLITE SERVICES                                                                  
                                    --------------------------------                                                            
     In thousands                       CWS       CMC       TOTAL        CI        LABS      OTHER      TOTAL                   
     -----------------------------------------------------------------------------------------------------------                
     <S>                              <C>       <C>       <C>         <C>        <C>       <C>        <C>                       
     1998                                                                                                                       
     Revenues:
          External customers          $301,781  $167,559  $  469,340  $113,106   $34,023   $      -   $  616,469
          Intersegment                   1,326     1,508       2,834       162     8,299    (11,295)           -
                                    ----------------------------------------------------------------------------
          Total                        303,107   169,067     472,174   113,268    42,322    (11,295)     616,469
      
     Operating income (loss)           107,268    29,740     137,008   (39,789)   (1,760)   (35,957)      59,502
     Segment income (loss)             113,110    31,864     144,974   (20,983)   (3,508)   (88,275)      32,208
     Total assets                      784,192   454,696   1,238,888   342,704    13,454    195,752    1,790,798
     Capital expenditures              129,497    28,646     158,143    61,727     1,266      3,593      224,729
     Depreciation and amortization     112,283    64,148     176,431    38,675     1,214      3,563      219,883
     -----------------------------------------------------------------------------------------------------------                 
     1997
     Revenues:
          External customers          $285,179  $164,371  $  449,550  $ 88,550   $24,551   $      -   $  562,651
          Intersegment                   1,002     3,479       4,481     1,111    11,820    (17,412)           -
                                    ----------------------------------------------------------------------------
          Total                        286,181   167,850     454,031    89,661    36,371    (17,412)     562,651
      
     Operating income (loss)            99,974    23,114     123,088   (13,975)   (2,043)   (25,102)      81,968
     Segment income (loss)             102,646    23,854     126,500    (8,888)   (1,780)   (71,651)      44,181
     Total assets                      761,338   509,504   1,270,842   322,704    14,133    287,096    1,894,775
     Capital expenditures               88,120    54,457     142,577   114,110     1,173      1,639      259,499
     Depreciation and amortization      97,821    57,204     155,025    25,623       991      2,567      184,206
     -----------------------------------------------------------------------------------------------------------                
     1996
     Revenues:
          External customers          $296,624  $158,749  $  455,373  $ 58,084   $31,643   $      -   $  545,100
          Intersegment                   1,130     2,173       3,303         -    12,043    (15,346)           -
                                    ----------------------------------------------------------------------------
          Total                        297,754   160,922     458,676    58,084    43,686    (15,346)     545,100
      
     Operating income (loss)           109,719    31,872     141,591   (17,281)    7,098    (24,183)     107,225
     Segment income (loss)             111,023    34,861     145,884   (14,694)    7,335    (73,404)      65,121
     Total assets                      808,646   503,342   1,311,988   253,649    16,593    515,056    2,097,286
     Capital expenditures              110,231    70,616     180,847    89,857     1,009      1,193      272,906
     Depreciation and amortization      92,185    45,207     137,392    14,814       956      2,134      155,296
     -----------------------------------------------------------------------------------------------------------
     </TABLE>

     International's operating loss in 1998 includes a $14,000,000 non-cash
     impairment loss on long-lived assets (see Note 7) and its 1998 segment loss
     includes a realized gain of $14,635,000 from the sale of a marketable
     equity security (see Note 6).

     CWS's segment income in 1998 includes a $4,303,000 gain from a settlement
     with ICO (see Note 6).

     Labs' 1996 revenues includes $7,800,000 related to a licensing agreement
     that resolved patent infringement disputes.

                                       77
<PAGE>
 
     Related Party Transactions.  The corporation provides support services to
     INTELSAT and support services and satellite capacity to Inmarsat.  The
     revenues from these services were $15,385,000 in 1998, $16,364,000 in 1997
     and $17,996,000 in 1996. These revenues were recorded primarily in CWS, CMC
     and Labs.

     Major Customers.  Revenues from three major customers contributed
     $235,637,000, $224,683,000 and $212,073,000 to the corporation's
     consolidated revenues in 1998, 1997 and 1996, respectively.

     Geographic Information.  Revenues are attributed to geographic areas based
     on the location of the assets producing the revenues.  Satellite services
     revenues generated through the INTELSAT, New Skies and Inmarsat satellites
     are ascribed to the United States.  The foreign amounts primarily consist
     of CI's companies in Latin America.  Financial information relating to the
     corporation's operations by geographic area is as follows:

<TABLE>
<CAPTION>
                                   Revenues                             
                      ----------------------------------                
     In thousands        1998        1997        1996           
     ---------------------------------------------------        
     <S>              <C>         <C>         <C>               
     United States    $  503,363  $  474,101  $  487,016        
     Foreign             113,106      88,550      58,084        
                      ----------  ----------  ----------        
     Total            $  616,469  $  562,651  $  545,100        
                      ==========  ==========  ==========        
                                                                
                            Property and Equipment              
                      ----------------------------------                
     In thousands           1998        1997        1996                
     ---------------------------------------------------                
     United States    $  954,953  $1,123,750  $1,177,135                
     Foreign             254,509     235,543     145,850                
                      ----------  ----------  ----------                
     Total            $1,209,462  $1,359,293  $1,322,985                
                      ==========  ==========  ==========                
</TABLE>        

                                       78
<PAGE>
 
17.  QUARTERLY FINANCIAL INFORMATION (Unaudited)
                                        
<TABLE>
<CAPTION>
 In thousands, except per                                                            
 share amounts                 1st Quarter          2nd Quarter           3rd Quarter           4th Quarter        Total Year 
- ------------------------------------------------------------------------------------------------------------------------------
<S>                            <C>                   <C>                  <C>                   <C>                 <C> 
1998:
Revenues                         $144,717             $151,045              $158,415              $162,292            $616,469
Operating income                   19,676               20,962                 2,377      (2)       16,487     (4)      59,502
Net income                          3,850     (1)        4,074                 6,569      (3)       11,924     (5)      26,417
Earnings per share:
    Basic                            0.08                 0.08                  0.13                  0.23                0.51
    Assuming dilution                0.07                 0.08                  0.12                  0.22                0.50
Dividends per share                  0.05                 0.05                  0.05                  0.05                0.20
Stock price:
    High                               36                   42     3/4            36     7/8            39    5/8           42   3/4
    Low                                21    5/8            27     3/4            21   13/16            32   7/16           21   5/8
    Close                              34   7/16            28    5/16            35     1/4            36                  36
 
Revenues                         $133,531             $142,437              $145,332              $141,351            $562,651
Operating income                   23,151               23,412                17,653                17,752              81,968
Income from continuing
 operations
   before extraordinary item        8,099                9,098      (6)        9,395      (7)        1,976     (6)      28,568
Loss from discontinued            (12,380)             (16,481)              (30,207)              (30,000)            (89,068)
 operations                 
Extraordinary loss                 (1,010)              (2,936)                    -                     -              (3,946)
Net loss                           (5,291)             (10,319)              (20,812)              (28,024)            (64,446)
Earnings (loss) per share:
  Basic:
    Income from continuing
     operations
     before extraordinary item       0.17                 0.19                  0.19                  0.04                0.58
    Loss from discontinued   
     operations                     (0.26)               (0.34)                (0.62)                (0.61)              (1.82) 
    Extraordinary loss              (0.02)               (0.06)                    -                     -               (0.08)
    Net loss                        (0.11)               (0.21)                (0.42)                (0.57)              (1.32)
  Assuming dilution:
    Income from continuing
     operations
  before extraordinary item          0.16                 0.18                  0.19                  0.04                0.57
    Loss from discontinued
     operations                     (0.25)               (0.33)                (0.60)                (0.59)              (1.78)
    Extraordinary loss              (0.02)               (0.06)                    -                     -               (0.08)
    Net loss                        (0.11)               (0.21)                (0.41)                (0.55)              (1.29
Dividends per share                  0.195                 0.05                  0.05                  0.05               0.345
Stock price:        
   High                                28    1/2            26   11/16            24    5/16            25    3/4           28   1/2
   Low                                 23                   19     5/8            20   13/16            20   5/16           19   5/8
   Close                               24    3/8            23   13/16            23   13/16            24    1/4           24   1/4
</TABLE>
      
     (1) The first quarter of 1998 includes the $1,950,000 non-cash write-off of
         an investment.
     (2) The third quarter of 1998 includes $3,500,000 of merger costs and a
         $14,000,000 non-cash impairment loss related to the write-down of long-
         lived assets.
     (3) The third quarter of 1998 includes a reversal of previously accrued
         interest costs and taxes totaling $19,206,000 net of tax, relating to
         the resolution of certain state and federal income tax matters.
     (4) The fourth quarter of 1998 includes merger costs of $2,025,000.
     (5) The fourth quarter of 1998 includes a pre-tax gain of $13,960,000 from
         the sale of a marketable equity security and income of $4,303, 000 from
         a settlement with ICO.
     (6) The second and fourth quarters of 1997 includes a pre-tax gain of
         $1,987,000 from the sale of a marketable equity security and a pre-tax
         loss of $1,008,000 for a decline in value of a marketable equity
         security, respectively.
     (7) The third quarter of 1997 includes a pre-tax gain of $7,261,000 from
         the sale of land.

                                       79
<PAGE>
 
Item 9:  Changes in and Disagreements with Accountants on Accounting and
         Financial Disclosure

     None.
 

                                       80
<PAGE>
 
                                   PART III

Item 10:  Directors and Executive Officers of the Registrant

                          DIRECTORS OF THE REGISTRANT

     The Satellite Act provides that the Corporation's Board of Directors shall
consist of 15 directors, of whom 12 are to be elected annually by the
shareholders for terms of one year and three are to be appointed by the
President of the United States, with the advice and consent of the U.S. Senate,
for terms of three years or until their successors have been appointed and
qualified.  The Corporation's Board of Directors currently consists of 14
directors, pending Presidential appointment and Senate confirmation to fill an
existing vacancy in one of the Presidentially-appointed director positions.

     The following sets forth certain information concerning the directors of
the Corporation.

Elected Directors

Betty C. Alewine, 50, has been President and Chief Executive Officer of COMSAT
since July 1996. She was President, COMSAT International Communications from
January 1995 to July 1996, and was President, COMSAT World Systems from May 1991
to January 1995.  She joined COMSAT from MCI Communications Corporation in 1986
and has been a director of the Corporation since July 1996.  She also is a
director of New York Life Insurance Co. and the Cancer Research Foundation of
America, a not-for-profit corporation.  She is a member of the Inter-American
Development Bank Advisory Council, the Business-Higher Education Forum and the
American Institute of Aeronautics and Astronautics.

Marcus C. Bennett, 63, is a director of various organizations.  He was Executive
Vice President and Chief Financial Officer of Lockheed Martin Corporation from
1995 to January 1999 and is a director of Lockheed Martin Corporation.  He has
been a COMSAT director since August 1997.  He also is a director of Carpenter
Technology Corporation and Martin Marietta Materials, Inc. and a member of the
board of directors of the Private Sector Council and the Georgia Tech Advisory
Board.

Lucy Wilson Benson, 71, has been a director of various business, educational and
nonprofit organizations since 1980.  She was Under Secretary of State for
Security Assistance, Science and Technology from 1977 to 1980.  She has been a
COMSAT director since September 1987.  She also is a director of Logistics
Management Institute, a trustee of the Alfred P. Sloan Foundation and Vice
Chairman of the Atlantic Council of the U.S., the Board of Trustees of Lafayette
College and the Citizens Network for Foreign Affairs.  She also is a director or
trustee of funds of The Dreyfus Corporation.

Edwin I. Colodny, 72, has been Chairman of the Board of COMSAT since April 1997
and a director since May 1992.  He was Chairman of US Airways Group, Inc. and of
its subsidiary, US Airways, Inc., a commercial airline company, from 1978 until
July 1992 and was a director of both corporations until May 1997.  He was Chief
Executive Officer of US Airways Group from 1983 to June 1991 and of its
subsidiary, US Airways, Inc., from 1975 to June 1991.  He has served as counsel
to the Washington, D.C. law firm of Paul, Hastings, Janofsky and Walker since
September 1991.

                                       81
<PAGE>
 
Lawrence S. Eagleburger, 68, has been Senior Foreign Policy Advisor for Baker,
Donelson, Bearman & Caldwell, a Washington, D.C. law firm, since January 1993.
He previously served as United States Secretary of State from December 1992
through January 1993, Acting Secretary of State from August 1992 to December
1992, and Deputy Secretary of State from February 1989 to August 1992.  He has
been a COMSAT director since May 1995.  He also is a director of Phillips
Petroleum Company, Stimsonite Corporation, Universal Corporation and Halliburton
Industries, and Chairman of the International Commission on Holocaust Era
Insurance Claims.

Neal B. Freeman, 58, has been Chairman and Chief Executive Officer of The
Blackwell Corporation, a television production and distribution company, since
1981.  He was a Presidentially-appointed COMSAT director from November 1983 to
September 1988 and has been an elected director since May 1991.  He also is Vice
Chairman of The Ethics and Public Policy Center and a director of Forum Network,
Inc. and National Review, Inc.

Caleb B. Hurtt, 67, is a director or trustee of various organizations.  He was
President of Martin Marietta Aerospace from 1982 to 1987 and then President and
Chief Operating Officer of Martin Marietta Corporation from 1987 through 1989.
He has been a COMSAT director since May 1996. He also is a director of Lockheed
Martin Corporation and has served as Chairman of the Board of Governors of the
Aerospace Industries Association, as Chairman of the NASA Advisory Council, as
Chairman of the Federal Reserve Bank, Denver Branch, and as Vice Chairman of the
Board of Trustees of Stevens Institute of Technology.

Peter W. Likins, 62, has been President of The University of Arizona since
October 1997.  He was President of Lehigh University from 1982 to September
1997, Provost of Columbia University from 1980 to 1982 and Professor and Dean of
the Columbia University School of Engineering and Applied Science from 1976 to
1980.  He has been a COMSAT director since September 1987.  He also is a
director of Parker Hannifin, Inc. and Safeguard Scientifics, Inc. and a trustee
of Consolidated Edison Company of New York, Inc. and of the University Medical
Center in Tucson, Arizona.

Larry G. Schafran, 60, has been the Managing General Partner of L.G. Schafran &
Associates, a real estate investment and development firm, since 1984.  He was
Chairman of the Executive Committee of Dart Group Corporation from 1994 to
October 1997 and a director of Dart from 1993 to October 1997.  He has been a
COMSAT director since August 1997.  He also is a director of PubliCARD, Inc.,
Tarragon Realty Investors, Inc., Discovery Zone, Inc. and Kasper A.S.L., Ltd.
and Chairman of the Board of Directors of Delta-Omega Technologies, Inc.

Robert G. Schwartz, 70, is a director or trustee of various business
organizations.  He was Chairman of the Board, President and Chief Executive
Officer of Metropolitan Life Insurance Co. (MetLife) from September 1989 to
March 1993 and remains a director of MetLife.  He was Chairman of the Board of
MetLife from February 1983 to September 1989.  He has been a COMSAT director
since May 1986.  He also is a trustee of Consolidated Edison Company of New
York, Inc. and a director of Lone Star Industries, Inc., Lowe's Companies, Inc.,
Mobil Oil Corporation, Potlatch Corporation and the Horatio Alger Association
for Distinguished Americans.

                                       82
<PAGE>
 
Kathryn C. Turner, 51, is the Chairperson and Chief Executive Officer of
Standard Technology, Inc., a high-technology, engineering and systems
integration firm.  She previously has been appointed by the President to serve
on the President's Export Council, the Eximbank Advisory Committee, and the
Commission on the Future of Worker-Management Relations and by the Secretary of
Defense to the Defense Policy Advisory Committee on Trade.  She has been a
COMSAT director since August 1997.  She also is a director of Phillips Petroleum
Company and Carpenter Technology Corporation.

Guy P. Wyser-Pratte, 58, is President of Wyser-Pratte & Co., Inc. and Wyser-
Pratte Management Co., Inc.  He has been a COMSAT director since August 1997.
He also is a director of The Eureka (US$) Fund, The Eureka (DM) Fund and the
International Rescue Committee, a non-governmental international refugee
organization, a member of the Council on Foreign Relations and a trustee of the
U.S. Marine Corps University Foundation.

Presidentially-Appointed Directors

Peter S. Knight, 49, has been a partner in the Washington, D.C. law firm of
Wunder, Knight, Levine, Thelen & Forscey since 1991.  In 1996, he took a leave
of absence from his firm to serve as Campaign Manager for Clinton/Gore '96.
From 1989 to 1991, he was General Counsel and Secretary of the Medicis
Pharmaceutical Corporation.  From 1977 to 1989, he served as the Chief of Staff
to Congressman and later Senator Al Gore.  He has been a Presidentially-
appointed COMSAT director since September 1994.  He also is a director of the
Medicis Pharmaceutical Corporation, Whitman Education Group Inc., Healthworld
and the Schroder Series Trust.  His current term expires at the 1999 Annual
Meeting.

Charles T. Manatt, 62, is the Chairman of Manatt, Phelps & Phillips, a
Washington, D.C. and Los Angeles law firm which he founded in 1965.  He was
Chairman of the Democratic National Committee from 1981 through 1985.  He has
been a Presidentially-appointed COMSAT director since May 1995.  He also is a
director of the Federal Express Corporation and ICN Pharmaceuticals, Inc.  His
current term expired at the 1997 Annual Meeting, and he continues to serve in
accordance with the Satellite Act.

                      EXECUTIVE OFFICERS OF THE REGISTRANT

<TABLE>
<CAPTION>
Name                                          Title                         Age*
- --------------------------------------------------------------------------------
<S>                    <C>                                                  <C>
Betty C. Alewine       President and Chief Executive Officer                  50
Edward E. Berger       Treasurer                                              41
Allen E. Flower        Vice President and Chief Financial Officer             55
Alan G. Korobov        Controller                                             50
John H. Mattingly      President, COMSAT Satellite Services                   48
Benjamin A. Pontano    President, COMSAT Laboratories                         55
James J. Welch         President and General Manager, COMSAT International    54
Warren Y. Zeger        Vice President, General Counsel and Secretary          51
</TABLE>

* As of February 1, 1999.

     Normally, the officers are elected annually by the Board of Directors at
its first meeting following the Annual Meeting of Shareholders to serve until
their successors are elected and qualified.

                                       83
<PAGE>
 
     There is no family relationship between any director or executive officer
and any other executive officer or director.  There is no arrangement or
understanding between any director or executive officer and any other person
pursuant to which he or she was selected as a director or executive officer.

     The following is a brief account of each executive officer's experience for
the past five years:

     Mrs. Alewine has been President and Chief Executive Officer since July
1996.  She was President, COMSAT International Communications from January 1995
to July 1996, and was President, CWS, from May 1991 to January 1995.  She is
also a member of the Board of Directors of the Corporation.

     Mr. Berger has been Treasurer since September 1998.  He previously worked
for Sprint Corporation in various financial capacities, where in his last
position he was responsible for all of Sprint's international treasury
activities.

     Mr. Flower has been Vice President and Chief Financial Officer since
November 1995. From November 1995 to September 1996, he was also Acting
Treasurer. He was Controller and Acting Chief Financial Officer from April 1995
through November 1995 and Controller from June 1992 to May 1995. He is a
director of Calian Technology Ltd., in which the Corporation holds a minority
equity investment.

     Mr. Korobov has been Controller since November 1995.  He was Vice
President, Finance for CMC from January 1993 to September 1995.

     Mr. Mattingly has been President, COMSAT Satellite Services since September
1997. He was President, COMSAT World Systems from May 1997 to September 1997 and
Vice President and General Manager, COMSAT World Systems from March 1995 to May
1997. He previously served as Vice President, Europe, COMSAT International
Ventures. Before joining COMSAT in November 1994, he was Senior Vice President
and General Manager of OrionNet, Inc.

     Dr. Pontano has been President, COMSAT Laboratories since March 1997,
having served as Acting President, COMSAT Laboratories from August 1996.  He was
Vice President, Network Technology Division of COMSAT Laboratories from February
1995 to August 1996.  He joined COMSAT Laboratories in 1984 and has held various
management positions during that period.

    Mr. Welch has been President and General Manager, COMSAT International since
November 1998.  He previously worked for Global One, a joint venture of Sprint,
France Telecom and Deutsche Telekom, where in his last position he was Vice
President and Area Manager for Russia, India, Middle East and Africa.

     Mr. Zeger has been Vice President, General Counsel and Secretary since
August 1994. He was Vice President and General Counsel from March 1992 to August
1994.

                                       84
<PAGE>
 
Compliance with Section 16(a) of the Exchange Act

     Two reports, each concerning one transaction, were filed late in 1998 by
Mr. Wyser-Pratte, a director of the Corporation.

     Two transactions by Mr. Flower, an executive officer of the Corporation,
that had been previously reported on a Form 144, were inadvertently omitted from
a subsequent report concerning the same series of transactions.  An amended
report was subsequently filed to correct the omission.

                                       85
<PAGE>
 
Item 11:  Executive Compensation

                             DIRECTORS COMPENSATION

Generally

     Directors, other than the Chairman of the Board and the President and Chief
Executive Officer, currently receive an annual retainer of 1,000 shares of
COMSAT's common stock payable at the first meeting of the Board after the Annual
Meeting of Shareholders.  Those directors also receive a fee of $1,000 per
meeting for attending Board meetings, Board committee meetings or meetings held
pursuant to a special assignment.  For service as chair of a Board committee, a
director receives an annual retainer of $3,000 paid in quarterly installments.
The President and Chief Executive Officer does not receive separate compensation
for service as a director.  Executive compensation is described in the section
entitled "Executive Compensation."

     Under the Non-Employee Directors Stock Plan, a non-employee director may
elect to defer receipt of the annual stock retainer and instead receive phantom
stock units (PSUs).  PSUs are held in an account for each director pending
retirement or termination of service on the Board.  Upon payment of a dividend
on COMSAT's common stock, an equivalent dollar amount is converted to PSUs,
based on the fair market value of the stock on the dividend payment date, and
credited to the director's account.  The PSUs increase or decrease in value
based on an equivalent number of shares of COMSAT's common stock.  Upon
retirement or termination of service, or in the event of a "Change in Control",
a director receives payment in shares of COMSAT's common stock equal to the
number of PSUs credited to the director's PSU account.  See "Non-Employee
Directors Stock Plan."
 
Chairman of the Board

     The Chairman of the Board receives annual cash compensation for service as
Chairman. Prior to August 1998, Mr. Colodny received $190,000 per year.
Effective August 1, 1998, this amount was increased to $215,000.  The Chairman
may elect to receive all or a portion of this annual cash compensation in the
form of COMSAT common stock or stock options, on the following terms:

     .    the shares or stock options are granted on the date of the Annual
          Meeting of Shareholders;

     .    the number of shares of stock granted is determined by dividing the
          amount which the Chairman elects to receive in shares by the fair
          market value of the stock on the date of the grant;

     .    the number of stock options granted is determined by multiplying the
          amount which the Chairman elects to receive in options by three and
          then dividing by the fair market value of the stock on the date of
          grant;

     .    the exercise price per share of options granted pursuant to the
          Chairman's election to receive options is the fair market value of a
          share of stock on the date of grant; and

                                       86
<PAGE>
 
     .    each option expires 10 years from the date of grant and is
          exercisable for half of the shares covered by the option six months
          after the date of grant and for the remaining half of the shares one
          year after such date.

     For 1998, Mr. Colodny elected to receive $90,000 of the annual cash
compensation payable to him as Chairman in stock.  Pursuant to his election, he
was granted 2,341 shares of common stock determined in the manner described
above.

Directors and Executives Deferred Compensation Plan

     Under the Directors and Executives Deferred Compensation Plan, a non-
employee director may elect to defer payment of all or part of the cash retainer
and fees which the director is entitled to receive.  Amounts deferred are
credited with interest and are paid out after the director retires from the
Board.  The payment may take the form of a lump sum or up to 15 annual
installments beginning not later than age 73.  If the director dies, the
accumulated deferrals are paid to the director's beneficiary.
 
     For 1998:
 
     .    the interest crediting rate was prime plus 1% for amounts deferred
          after 1996, 12.25% for amounts deferred from February 1994 to December
          1996 and 12.94% for amounts deferred prior to that period under the
          plan; and

     .    the aggregate amount of interest accrued in respect of amounts
          deferred by participating directors (11 persons) was $380,272.

     In 1991, each director at that time serving on the Board and participating
in the plan was given an election to receive his or her account balance as of
March 31, 1991, together with interest accumulated on such balance to a date in
2000, in a lump sum in 2000 to the extent that such amounts were not previously
distributed.  This payment is made only if, in 2000, such director is an active
director or a retiree receiving installment payments.  If a director who has
made such an election dies, the payment will be made to the beneficiary of such
director if such beneficiary is then receiving such installment payments.  The
lump sum payment will be offset against the amounts otherwise payable to the
director or beneficiary under the plan.

     In 1992, the plan was amended to provide for an additional lump sum payment
election for any additional amounts deferred under the plan from April 1, 1991
through March 31, 1992, together with interest accumulated on such amounts to a
date in 2001, with payment of the lump sum to be made in 2001.
 
     In September 1998, the plan was amended to provide that if the plan is
terminated, each participant will be paid the full amount of his or her account
in accordance with the terms of the plan and the participant's elections.

                                       87
<PAGE>
 
Split Dollar Life Insurance Plan for Directors

     Under the Split Dollar Life Insurance Plan for Directors, COMSAT provides
death benefits through split dollar life insurance policies to non-employee
directors as follows:
 
     .    $50,000 for each year or partial year of his or her Board service
          until the benefit reaches $200,000;

     .    payments increased by 5.5% for each additional year of Board service
          to age 72 (this increased coverage does not apply to Presidentially-
          appointed directors); and

     .    coverage continues after retirement from the Board.

     For 1998, the aggregate value of split dollar life insurance premiums paid
for the benefit of all covered directors was $112,891.

Non-Employee Directors Stock Plan

     Under the Non-Employee Directors Stock Plan, in March of each year COMSAT
grants to each non-employee director an option to purchase shares of common
stock.  These grants are only given to those non-employee directors who were
also serving on the date of the Annual Meeting of Shareholders for the prior
year.  Certain options have specific terms, as follows:
 
     .    for options granted before 1990, each option is for 2,480 shares, the
          exercise price per share is the fair market value of a share of common
          stock on the date of grant, and the option expires 10 years from the
          date of grant;

     .    for options granted from 1990 to 1992, each option is for 2,480
          shares, the exercise price per share is 50% of the fair market value
          on the date of grant, and the option expires 15 years from the date of
          grant;

     .    for options granted after 1992, each option is for 4,961 shares, the
          exercise price per share is the fair market value of a share of common
          stock on the date of grant, and the option expires 15 years from the
          date of grant;

     .    all options granted before 1996 under the plan are currently
          exercisable; and

     .    for options granted after 1995, each option becomes exercisable for
          2,481 shares one year after the date of grant and for the remaining
          2,480 shares two years after the date of grant.

     All data related to shares of common stock, options to purchase shares of
common stock and share prices prior to June 27, 1997 have been adjusted to
reflect (1) the two-for-one split in COMSAT's common stock effective June 1,
1993, and (2) the spin-off of Ascent Entertainment Group, Inc. to COMSAT's
shareholders on June 27, 1997.  Pursuant to the Ascent spin-off, all outstanding
options under the plan on June 27, 1997 were adjusted by multiplying the number
of options held by an adjustment ratio of 1.2402, and the exercise price for
such options was adjusted by dividing the exercise price by the same ratio.

                                       88
<PAGE>
 
     Options become fully exercisable and continue in force for the duration of
their terms in the following situations:
 
     .    termination of service on the Board by reason of retirement at age 72;

     .    expiration of a term as a Presidentially-appointed director;

     .    failure to stand for election with the Board's consent; or

     .    resignation with the Board's consent.

     Options that have not terminated become fully exercisable and continue in
force for one year after the date of death of a director.  Options terminate
immediately if the director's service terminates under any other circumstance.
 
     Options also become fully exercisable and continue in force for the
duration of their terms in the event of certain changes in control.  A "Change
in Control" includes:
 
     .    the acquisition by any person (other than COMSAT or an employee
          benefit plan sponsored by COMSAT) of beneficial ownership of 50% or
          more of the outstanding voting securities of COMSAT;

     .    any change in the composition of the Board of Directors such that the
          elected directors as of May 17, 1996 (referred to as the Incumbent
          Directors) cease to constitute a majority of the Board (provided that
          any individual whose nomination or election is approved by a vote of
          three-fourths of the then Incumbent Directors will be treated as an
          Incumbent Director);

     .    approval by the shareholders of a merger, share exchange, swap,
          consolidation, recapitalization or other business combination which,
          if consummated, would result in COMSAT's shareholders holding less
          than 60% of the combined voting power of COMSAT, the surviving entity
          or its parent (as applicable);

     .    approval by the shareholders of the liquidation or dissolution of
          COMSAT, or sale by COMSAT of all or substantially all of COMSAT's
          assets, other than to an entity 80% of the combined voting power of
          which would be beneficially owned by COMSAT's then existing
          shareholders; or

     .    any event which would have to be reported as a "change of control"
          under the regulations governing the solicitation of proxies by the
          SEC.

                                       89
<PAGE>
 
     In September 1998, the plan was amended to provide that only the closing of
the Merger with Lockheed Martin Corporation, and not any of the other
transactions contemplated by the Merger Agreement, would constitute a "Change in
Control" for purposes of this plan.

     In 1998, options for a total of 64,493 shares of common stock were granted
to non-employee directors at a purchase price per share of $38.1563, which was
the fair market value of the common stock on the date of grant.  In 1998, Mrs.
Benson, Mr. Freeman, Dr. Likins and Mr. Schwartz each exercised 2,480 options
granted previously under the plan, and realized net values (market value on
exercise date less exercise price) of $52,130; $29,810; $47,325; and $27,950,
respectively.
 
Consulting Arrangements

          On August 26, 1997, COMSAT entered into agreements with Arthur
Hauspurg and Howard M. Love, directors who retired at the 1997 Annual Meeting of
Shareholders, to retain their advisory services to the Chairman of the Board and
the President and Chief Executive Officer for a period of two years at a rate of
$25,000 per year.

                                       90
<PAGE>
 
                             EXECUTIVE COMPENSATION

     The following table shows the compensation for the three fiscal years ended
December 31, 1998 received by (i) the Chief Executive Officer; (ii) the other
four most highly compensated executive officers of COMSAT who were serving as
such at year end 1998; and (iii) Dwight E. Jasmann, who resigned as an executive
officer on February 2, 1998, and whose compensation would have been reportable
but for the fact that he was not an executive officer of COMSAT at year end
1998.  These six individuals are referred to as the Named Executive Officers.
The table shows the amounts received or earned by each Named Executive Officer
for all three fiscal years, whether or not such Named Executive Officer was an
executive officer of COMSAT for each of those three years.

                           Summary Compensation Table

<TABLE>
<CAPTION>
                                           Annual Compensation                        Long-Term Compensation
                         ----------------------------------------------------------------------------------------
<S>                <C>    <C>      <C>         <C>               <C>           <C>             <C>  
Name and                                                            Restricted     Securities
 Principal                                        Other Annual        Stock       Underlying        All Other
 Position            Year   Salary   Bonus (1)  Compensation (2)   Award(s)(3)   Options(#)(4)   Compensation(5)
- ----------------------------------------------------------------------------------------------------------------- 
Betty C.             1998  $533,173  $406,258             $   665      $182,625          30,000           $22,736
Alewine,             1997   472,116   306,756               8,370       498,749               0            22,135
President and        1996   355,846   189,111               3,238       238,188         260,442            20,799
Chief         
Executive
Officer
- ----------------------------------------------------------------------------------------------------------------- 
Allen E.             1998   251,516   211,248                 580       121,750          25,000            33,318
Flower, Vice         1997   209,770    83,627               5,622       174,554          49,608            36,855
President and        1996   180,000    73,301              60,122        90,000          43,407            31,578
Chief
Financial
Officer
- ----------------------------------------------------------------------------------------------------------------- 
Dwight E.            1998   252,000   142,396                  44             0               0             9,887
Jasmann,             1997   244,985   204,187              39,961             0          18,603             4,750
President and        1996    98,770   203,600              13,795        97,813          12,402               923
General
Manager,
COMSAT
International(6)
- ----------------------------------------------------------------------------------------------------------------- 
John H.              1998   270,539   173,146                   0        91,313          20,000             4,800
Mattingly,           1997   190,308    75,029                   0        74,820          24,804             4,750
President,           1996   162,039    57,274                   0        35,994          12,402             4,498
COMSAT
Satellite
Services
- ----------------------------------------------------------------------------------------------------------------- 
Benjamin A.          1998   197,667    60,000                   0        60,875          15,000             5,545
Pontano,             1997   152,663    50,000                   0        49,867          18,603             4,610
President,           1996   130,000    42,600                   0             0           3,721             3,900
COMSAT
Laboratories
- ----------------------------------------------------------------------------------------------------------------- 
Warren Y.            1998   286,836   220,997                 521       121,750          25,000            27,419
Zeger,               1997   229,808    94,348               5,466       174,554          49,608            26,938
Vice President,      1996   196,551   181,487               2,422        63,000          37,206            25,871
General
Counsel and
Secretary
- -----------------------------------------------------------------------------------------------------------------
</TABLE>

                                       91
<PAGE>
 
(1)  Bonus for 1998 for each Named Executive Officer, as indicated below,
     includes unused credits under the Corporation's cafeteria plan that were
     paid in cash to the Named Executive Officers.  The bonus reflected for Mrs.
     Alewine for 1997 includes an additional $85,000 over the amount reported
     last year, which was awarded in 1998 to Mrs. Alewine as a supplemental 1997
     bonus.  The bonuses reflected for Mr. Flower, Mr. Mattingly and Mr. Zeger
     for 1998 include special performance-based spot bonuses in the amounts of
     $100,000; $50,000; and $100,000, respectively.  The bonus reflected for Mr.
     Zeger for 1996 includes a special performance-based spot bonus in the
     amount of $100,000.

<TABLE>
<CAPTION>
  
                                            Unused
                           Name             Credits
                           ------------------------
<S>                       <C>              <C> 
                           Mrs. Alewine     $ 6,258
                           ------------------------
                           Mr. Flower        10,448
                           ------------------------
                           Mr. Jasmann       12,396
                           ------------------------
                           Mr. Mattingly      8,146
                           ------------------------
                           Dr. Pontano            0
                           ------------------------
                           Mr. Zeger          5,997
                           ------------------------
</TABLE>

(2)  With the exception of Mr. Flower, Other Annual Compensation shown for 1996,
     1997 and 1998 does not include perquisites and other personal benefits
     because the aggregate amount of such compensation does not exceed the
     lesser of (i)  $50,000 or (ii) 10% of individual combined salary and bonus
     for the Named Executive Officer in each year.  For Mr. Flower, Other Annual
     Compensation for 1996 includes $30,000 for club membership fees.

(3)  Includes restricted stock awards (RSAs), restricted stock units (RSUs) and
     phantom stock units (PSUs).  Dividends are paid on RSAs. Dividend
     equivalents are paid on RSUs and PSUs.  The number and value of the
     aggregate restricted stock holdings of each of the Named Executive Officers
     as of December 31, 1998 are as follows:

<TABLE>
<CAPTION> 
                                                    Value as      
                                    Number of          of   
                 Name             RSAs/RSUs/PSUs    12/31/98 
                 --------------------------------------------
<S>             <C>               <C>              <C>  
                 Mrs. Alewine             67,639   $2,358,910
                 --------------------------------------------
                 Mr. Flower               20,618      719,053
                 --------------------------------------------
                 Mr. Jasmann                   0            0
                 --------------------------------------------
                 Mr. Mattingly             9,201      320,885
                 --------------------------------------------
                 Dr. Pontano               9,441      329,255
                 --------------------------------------------
                 Mr. Zeger                29,300    1,021,838
                 --------------------------------------------
</TABLE>

     Awards granted prior to June 27, 1997 were adjusted to give effect to the
     Ascent spin-off to COMSAT shareholders.  In lieu of receiving a
     distribution of Ascent stock, all outstanding RSAs, RSUs and PSUs held on
     that date were adjusted by multiplying the number of shares or units held
     by an adjustment ratio of 1.2402.  Mr. Jasmann forfeited his restricted
     stock holdings when he resigned in February 1998.

(4)  Options granted prior to June 27, 1997 were adjusted to give effect to the
     Ascent spin-off to COMSAT shareholders.  All outstanding options held on
     that date were adjusted by multiplying the number of options held by an
     adjustment ratio of 1.2402.

(5)  All Other Compensation for 1998 includes the following elements:  (i)
     contributions by the Corporation to the Corporation's 401(k) Plan on behalf
     of the Named Executive Officers;  (ii)  above-market interest accrued for
     the Named Executive Officers under the Corporation's Deferred Compensation
     Plan;  and (iii)  life insurance premiums for the Named Executive Officers.
     The life insurance premiums shown for the Named Executive Officers
     represent split dollar premiums which include (i)  the value of the
     premiums paid by the Corporation with respect to the term life insurance
     portion of the policy for each Named Executive Officer, determined under
     the P.S. 58 table published by the Internal Revenue Service, and (ii)  the
     value of the benefit to each Named Executive Officer of the remainder of
     the premiums paid by the Corporation, determined by calculating the present
     value of the cumulative interest payments that would be made based on the
     assumption that the premiums were loaned to each Named Executive Officer at
     an interest rate of 7.5% until the Named Executive Officer reaches the
     normal retirement age of 65, at which time the policy splits and the
     premiums are refunded to the Corporation.

<TABLE>
<CAPTION>
 
                                                 Above-     Life   
                                 401(k) Plan     Market   Insurance 
                 Name           Contributions   Interest   Premiums   
             ------------------------------------------------------
<S>         <C>                 <C>            <C>        <C> 
             Mrs. Alewine            $4,800    $ 8,680     $ 9,256
            ------------------------------------------------------
             Mr. Flower               4,800     11,048      17,470
            ------------------------------------------------------
             Mr. Jasmann              4,800      5,087           0
            ------------------------------------------------------
             Mr. Mattingly            4,800          0           0
            ------------------------------------------------------
             Dr. Pontano              4,837        708           0
            ------------------------------------------------------
             Mr. Zeger                4,800      7,537      15,082
             -----------------------------------------------------
</TABLE>

(6)  Mr. Jasmann became an executive officer when he joined the Corporation as
     President and General Manager, COMSAT International in August 1996.  He
     resigned in February 1998.

                                       92
<PAGE>
 
Option Grants

     The following table sets forth information on options granted to the Named
Executive Officers in 1998.

Option Grants In Last Fiscal Year

<TABLE>
<CAPTION>
 ---------------------------------------------------------------------------------------------------------------------------
                                                    Individual Grants
 ---------------------------------------------------------------------------------------------------------------------------
                    Number of         % of Total Options
                   Securities            Granted to
               Underlying Options       Employees in       Exercise Price                        Grant Date Present 
Name             Granted (#)(1)        Fiscal Year(2)         ($/Sh)        Expiration Date          Value(3)
- ---------------------------------------------------------------------------------------------------------------------------
 <S>              <C>               <C>                <C>                 <C>              <C>
Mrs. Alewine            30,000              3.23%           $30.4375            02/20/08                 $375,300
- ---------------------------------------------------------------------------------------------------------------------------
Mr. Flower              25,000              2.69             30.4375            02/20/08                  312,750
- ---------------------------------------------------------------------------------------------------------------------------
Mr. Jasmann                  0              0.00              0.0000                 ---                        0
- ---------------------------------------------------------------------------------------------------------------------------
Mr. Mattingly           20,000              2.15             30.4375            02/20/08                  250,200
- ---------------------------------------------------------------------------------------------------------------------------
Dr. Pontano             15,000              1.61             30.4375            02/20/08                  187,650
- ---------------------------------------------------------------------------------------------------------------------------
Mr. Zeger               25,000              2.69             30.4375            02/20/08                  312,750
- --------------------------------------------------------------------------------------------------------------------------
</TABLE>

     (1)  The options shown were granted on February 20, 1998 to acquire the
          Corporation's Common Stock.  All options granted in 1998 vest as
          follows: 25% on the first anniversary of the date of grant; another
          25% on the second anniversary of the date of grant; and the remaining
          50% on the third anniversary of the date of grant.
     (2)  The total number of COMSAT options granted to key employees in 1998
          was 930,200.
     (3)  The Corporation used the Black-Scholes option pricing model to
          determine grant date present values using the following assumptions: a
          dividend yield of 0.84%; stock price volatility of 0.34642; a 6-year
          option term; a risk-free rate of return of 5.36%; and the vesting
          schedule described in footnote 1 above.  The use of this model is in
          accordance with SEC rules; however, the actual value of an option
          realized will be measured by the difference between the stock price
          and the exercise price on the date the option is exercised.

Option Exercises and Fiscal Year-End Values

     The following table sets forth information on (1) options exercised by the
Named Executive Officers in 1998, and (2) the number and value of their
unexercised options as of December 31, 1998.

         Aggregated Option Exercises In 1998 And 12/31/98 Option Values

<TABLE>
<CAPTION>
- ------------------------------------------------------------------------------------------------------------------------------ 
                                                    Number of Securities Underlying         Value of Unexercised In-The-Money  
                                                  Unexercised Options at 12/31/98(1)            Options at 12/31/98
- ------------------------------------------------------------------------------------------------------------------------------
                    Shares
                  Underlying
                    Options                                            Unexercisable
     Name        Exercised (#)   Value Realized    Exercisable (#)          (#)              Exercisable     Unexercisable
- -----------------------------------------------------------------------------------------------------------------------------
<S>              <C>             <C>             <C>                  <C>               <C>                 <C>
Mrs. Alewine         203,393      $2,615,608             229,726           160,221           $4,507,469         $2,451,773
- ----------------------------------------------------------------------------------------------------------------------------- 
Mr. Flower            16,371         306,763              58,910            83,910            1,178,565          1,102,292
- -----------------------------------------------------------------------------------------------------------------------------
Mr. Jasmann            7,750         103,664               3,101            20,154               59,233            324,497
- -----------------------------------------------------------------------------------------------------------------------------
Mr. Mattingly              0               0              16,122            44,804              289,640            489,728
- ----------------------------------------------------------------------------------------------------------------------------- 
Dr. Pontano                0               0              23,254            30,813              359,938            310,484
- ----------------------------------------------------------------------------------------------------------------------------- 
Mr. Zeger            111,618       1,909,430             111,797            80,809            1,805,076          1,039,153
- -----------------------------------------------------------------------------------------------------------------------------
</TABLE>


     (1)  Options granted prior to June 27, 1997 were adjusted to give effect to
          the Ascent spin-off to COMSAT shareholders.  All outstanding options
          held on that date were adjusted by multiplying the number of options
          held by an adjustment ratio of 1.2402.

                                       93
<PAGE>
 
Pension Plans

     The following table shows the estimated annual benefits payable upon
retirement under the Corporation's Retirement Plan to persons in the salary and
years-of-service classifications specified.  The Internal Revenue Code limits
the annual benefits payable under the Retirement Plan.  Under this limitation,
the maximum annual benefit for 1998 is $130,000.

Estimated Annual Benefits - COMSAT Corporation Retirement Plan

<TABLE>
<CAPTION>
- ----------------------------------------------------------------------------
                                            Years of Service
- ----------------------------------------------------------------------------
<S>                          <C>      <C>       <C>       <C>       <C>
Average Annual Salary ($)         15        20        25        30        35
- ----------------------------------------------------------------------------
       100,000               $24,768  $ 33,633  $ 42,738  $ 51,362  $ 60,227
- ----------------------------------------------------------------------------
       150,000                38,543    52,408    66,272    80,137    94,002
- ----------------------------------------------------------------------------
       200,000                48,552    67,417    86,282   105,147   124,011
- ----------------------------------------------------------------------------
       250,000                55,340    79,205   103,070   126,934   130,000
- ----------------------------------------------------------------------------
       300,000                60,340    89,205   118,070   130,000   130,000
- ----------------------------------------------------------------------------
       350,000                65,340    99,205   130,000   130,000   130,000
- ----------------------------------------------------------------------------
       400,000                70,340   109,205   130,000   130,000   130,000
- ----------------------------------------------------------------------------
       450,000                75,340   119,205   130,000   130,000   130,000
- ----------------------------------------------------------------------------
       500,000                80,340   129,205   130,000   130,000   130,000
- ----------------------------------------------------------------------------
       550,000                85,340   130,000   130,000   130,000   130,000
- ----------------------------------------------------------------------------
       600,000                90,340   130,000   130,000   130,000   130,000
- ----------------------------------------------------------------------------
</TABLE>

     The compensation covered by the Retirement Plan includes only base salary.
Benefits are determined on a straight life annuity basis under a formula based
on length of service and average annual base salary for the highest five
consecutive years during the final 10 years of employment.  Prior to 1989,
benefits were offset by a portion of each participant's estimated Social
Security benefits.  Beginning in 1989, each participant accrues a benefit at a
specified percentage of salary up to the Social Security wage base, and at a
higher percentage of salary above the Social Security wage base.  The years of
credited service for the Named Executive Officers as of December 31, 1998 are as
follows:
 
<TABLE>
<S>              <C>
- ------------------- 
Mrs. Alewine     12
- ------------------- 
Mr. Flower       29
- ------------------- 
Mr. Jasmann       2
- ------------------- 
Mr. Mattingly     4
- ------------------- 
Dr. Pontano      14
- ------------------- 
Mr. Zeger        23
- -------------------
</TABLE>

Insurance and Retirement Plan for Executives
 
     COMSAT also maintains the Insurance and Retirement Plan for Executives,
which covers those executive officers and other key employees who are designated
by the Board of Directors to participate. The plan provides an annuity for life
equal to 60% (70% for the Chief Executive Officer) of the participant's average
annual compensation (salary and incentive compensation) during the 48
consecutive months of highest compensation (or during all consecutive months of
employment if the participant has been employed less than 48 months), offset by
pension benefits payable under the Retirement Plan, the qualified retirement
plans of former employers, Social Security, and government and military
pensions.

     Payment begins upon the participant's normal retirement at age 65.
However, a participant in the plan may retire as early as age 55.  If a
participant retires before age 62, the Board must consent to such

                                       94
<PAGE>
 
early retirement. A participant who retires early will receive an annuity
reduced by 3% for each year that payment begins before age 62. For employees who
became participants in the plan before January 1, 1993, benefits vest ratably
over the first five years of the participant's service. For employees who become
participants in the plan on or after January 1, 1993, benefits are 50% vested
after five years of service and then vest an additional 10% per year over the
following five years of service, provided that the sum of the participant's age
and years of service equals 60. See "Agreements with Current Executive
Officers."

     The annual benefits payable upon retirement at age 65 based upon the 48
consecutive months of highest compensation as of December 31, 1998 for each of
the Named Executive Officers under the plan are:

<TABLE>
<S>              <C>
- ------------------------- 
Mrs. Alewine     $400,520
- ------------------------- 
Mr. Flower        107,739
- ------------------------- 
Mr. Jasmann           N/A
- ------------------------- 
Mr. Mattingly         N/A
- ------------------------- 
Dr. Pontano           N/A
- ------------------------- 
Mr. Zeger         114,452
- -------------------------
</TABLE>

     Mrs. Alewine, Mr. Flower and Mr. Zeger are each 100% vested in the plan.
Mr. Jasmann, Mr. Mattingly and Dr. Pontano do not participate in the plan.
 
Change in Control Severance Plan

     On September 18, 1998, COMSAT adopted the Amended and Restated Change in
Control Severance Plan.  The plan amends and restates the Change in Control
Severance Plan adopted by COMSAT on June 20, 1997.  The plan generally provides
severance payments and benefits to specified key employees, including certain
executive officers, of COMSAT who incur a termination of employment under
certain circumstances following a change in control of COMSAT.  The plan covers
Mr. Mattingly and Dr. Pontano but does not cover Mrs. Alewine, Mr. Flower or Mr.
Zeger, who each have severance arrangements under their employment agreements,
or Mr. Jasmann, who is no longer an executive officer. Participants under the
plan are classified as either Group I Participants, Group II Participants or
Group III Participants.  For purposes of the plan, the definition of change in
control is substantively identical to the definition of such term described
under the caption "Agreements with Current Executive Officers."

     Under the plan, if a change in control of COMSAT occurs and a participant's
employment is terminated during the period beginning on the date of the change
in control and ending on the date which is eighteen months after the date of
such change in control (a) by COMSAT other than for cause or disability, or (b)
by the participant for good reason, then, in lieu of any other severance
payments or severance benefits payable to the participant by the Company, the
participant will be entitled to receive the following during the benefits
continuation period:

          . base salary;

          . targeted annual bonus under COMSAT's Annual Incentive Plan; and

                                       95
<PAGE>
 
          . the same group health and welfare benefits to which the participant
            would have been entitled had he or she remained continuously
            employed by COMSAT during the benefits continuation period.

     For purposes of the plan, benefits continuation period means with respect
to each Group I, Group II and Group III Participant, respectively, the 24 month,
18 month and 15 month periods immediately following the participant's date of
termination of employment.  Mr. Mattingly and Dr. Pontano are Group I
Participants.

Retention Bonus Plan

     On September 18, 1998, COMSAT adopted the Retention Bonus Plan.  The
Retention Bonus Plan generally provides retention bonuses to specified key
employees who remain employed by COMSAT, or whose employment is terminated under
specific circumstances, through specified dates following the signing of the
either Group I Participants or Group II Participants.  The plan covers Mr.
Mattingly and Dr. Pontano, who are Group I Participants, but does not cover Mrs.
Alewine, Mr. Flower or Mr. Zeger, who each have similar bonus arrangements under
their employment agreements, or Mr. Jasmann, who is no longer an executive
officer.

     Under the Retention Bonus Plan, each Group I Participant will be entitled
to receive the following retention bonuses, subject to such person's continued
employment through a specified date:

          . a bonus on the earliest of:

            (a)  the completion of the Merger;
            (b)  the termination date of the Merger pursuant to the Merger
                 Agreement; or
            (c)  September 18, 2000, equal to 50% of the sum of the
                 participant's highest base salary plus his or her highest
                 targeted annual bonus under COMSAT's Annual Incentive Plan; and

          . a bonus on the 18-month anniversary of the closing of the Merger
            equal to 100% of the sum of the particpant's highest base salary
            plus his or her highest targeted annual bonus under COMSAT's Annual
            Incentive Plan.

     If, on or before the date on which a bonus would be paid, a Group I
Participant's employment is terminated without cause or by reason of his or her
death or disability, or, if a Group I Particpant elects to terminate his or her
employment for good reason, such Group I Particpant will be entitled to receive
a payment upon termination, instead of any bonuses which have not yet become
payable to the participant under the Retention Bonus Plan, in an amount equal to
the bonus to which he or she would have been entitled had he or she remained
employed by COMSAT through the date on which the next bonus will be paid.  If,
however, the aggregate amount of any severance payments to which the participant
is entitled under any severance plan of COMSAT is greater than or equal to the
amount of the bonus payable upon such a termination under the Retention Bonus
Plan, then the participant will forfeit all rights to receive such payment and
any other bonus payments that have not yet become payable to the participant
under the Retention Bonus Plan.  In the event that the participant receives a
payment upon

                                       96
<PAGE>
 
termination of employment under the Retention Bonus Plan, such plan of COMSAT to
the extent that such severance payment is based on the participant's salary
and/or bonus.

     Group II Participants are entitled to receive bonuses under the Retention
Bonus Plan at the same times and, in general, on the same terms as the Group I
Participants, except that the bonuses are based on a lower percentage of their
base salary and targeted annual bonus.

Agreements With Current Executive Officers
 
     COMSAT has entered into an employment agreement with Mrs. Alewine dated
July 19, 1996, and has entered into employment agreements with Mr. Flower and
Mr. Zeger dated April 18, 1997 (each an Executive and collectively the
Executives).  On September 18, 1998, COMSAT amended the employment agreements in
connection with the Lockheed Martin Merger.
 
     The agreements include the following terms:
 
     .    for Mrs. Alewine, successive three-year terms from each successive
          day after July 19, 1996 until July 19, 2003; for Mr. Flower, a three-
          year term; and for Mr. Zeger, a five-year term.  The amendments
          extended the term of Mr. Flower's employment agreement for two years
          until April 17, 2002;

     .    for Mrs. Alewine, base salary of $450,000 for the first year, with an
          increase to $500,000 in the second year; for Mr. Flower, base salary
          of $210,000 per year; for Mr. Zeger, base salary of $230,000 per year;
          for each Executive, further increases in base salary are subject to
          the discretion of COMSAT's Board;

     .    eligibility for an annual bonus based on performance measures
          determined by the Board's Compensation Committee with a target bonus
          equal to 70% of Mrs. Alewine's base salary, 50% of Mr. Flower's base
          salary, and 50% of Mr. Zeger's base salary;

     .    for termination without cause, or if the Executive elects to
          terminate his or her employment for good reason, the Executive will be
          entitled to receive:

          (a)  his or her then current base salary;
          (b)  an annual bonus equal to 70% of Mrs. Alewine's then current base
               salary, 50% of Mr. Flower's then current base salary, and 50% of
               Mr. Zeger's then current base salary; and
          (c)  all other benefits provided for pursuant to the agreement, which
               will be deemed fully and immediately vested if subject to
               vesting.

     Mrs. Alewine will be entitled to receive these amounts for three years from
     her termination date or until July 19, 2003, whichever is earlier, but in
     no case for less than one year following termination.  Mr. Flower will be
     entitled to receive these amounts until the later of one year from his
     termination date or April 17, 2002.  Mr. Zeger will be entitled to receive
     these amounts until April 17, 2002.

                                       97
<PAGE>
 
     .    if Mrs. Alewine's employment is not renewed after July 19, 2003, or
          is terminated before then either by Mrs. Alewine for good reason or by
          COMSAT without cause, Mrs. Alewine will be entitled to begin receiving
          retirement benefits at age 55 under the Insurance and Retirement Plan
          for Executives at the actuarially reduced rate for early retirement,
          subject to the Board's discretion to waive such reduction;

     .    if Mr. Flower's employment is not renewed after April 17, 2002, Mr.
          Flower will be entitled to receive (i) the benefits described above
          for one year thereafter and (ii) retirement benefits under the
          Insurance and Retirement Plan for Executives beginning on May 1, 2002
          at the actuarially reduced rate for early retirement, subject to the
          Board's discretion to waive such reduction;

     .    if Mr. Zeger's employment is not renewed after April 17, 2002, or is
          terminated before then either by Mr. Zeger for good reason or by
          COMSAT without cause, Mr. Zeger will be entitled to begin receiving
          retirement benefits at age 55 under the Insurance and Retirement Plan
          for Executives at the actuarially reduced rate for early retirement,
          subject to the Board's discretion to waive such reduction; and

     .    in the event that either Mr. Flower or Mr. Zeger dies after his
          employment terminates but before his retirement benefits begin, under
          the Insurance and Retirement Plan for Executives, his spouse will
          receive the death benefits provided in the plan for participants who
          die while employed by COMSAT.

     On October 17, 1996, Mrs. Alewine was granted (i) an option to purchase
186,030 shares of COMSAT's common stock at a price equal to the market value of
the stock on the grant date, which vests 25% after one year, another 25% after
the second year and the remaining 50% after the third year; and (ii) 6,201
restricted stock units which vest after three years.  On February 20, 1997, Mrs.
Alewine was also granted 24,804 restricted stock awards which are subject to the
same terms as restricted stock awards made to other executives of COMSAT on that
date.

     Pursuant to the amendments, the employment agreements were amended to
provide that, upon the occurrence of a change in control, the term of each
employment agreement will automatically end on the third anniversary of the date
of such change in control.
 
     As defined in the amendments, a change in control is deemed to have
occurred upon the happening of any one of the following events:
 
     .    the acquisition by any person of beneficial ownership of 50% or more
          of the combined voting power of the outstanding voting securities of
          COMSAT;

     .    any change in the composition of the Board of COMSAT such that the
          incumbent directors elected as of May 17, 1996 cease to constitute a
          majority of the Board; however, any individual whose nomination or
          election is approved by a vote of three-fourths of the then incumbent
          directors will be treated as an incumbent director;

                                       98
<PAGE>
 
     .    approval by the shareholders of a merger, share exchange, swap,
          consolidation, recapitalization or other business combination which,
          if consummated, would result in COMSAT's shareholders holding less
          than 60% of the combined voting power of COMSAT, the surviving entity
          or its parent;

     .    approval by the shareholders of the liquidation or dissolution of
          COMSAT, or sale by COMSAT of all or substantially all of COMSAT's
          assets, other than to an entity 80% of the combined voting power of
          which would be beneficially owned by COMSAT's then existing
          shareholders; or

     .    any event which would have to be reported as a "change of control"
          under the regulations governing the solicitation of proxies by the
          SEC.

     However, if, prior to the occurrence of any of the above events, the Board
adopts a resolution specifically providing that the event will not be deemed to
constitute a change in control for purposes of the employment agreements, then
such event will not constitute a change in control.
 
     The amendments provide that, with respect to the Lockheed Martin Merger, a
change in control of COMSAT for purposes of the employment agreements will be
triggered by the closing of the Merger, but not by the signing of the Merger
Agreement, the approval by the Board or COMSAT's shareholders of the Merger or
the Merger Agreement, the commencement or the closing of the Offer, or the
acquisition by Lockheed Martin or Regulus, LLC of COMSAT Government Systems,
Inc.

     The amendments also amended the employment agreements to provide that each
of the Executives will be entitled to receive the following retention bonuses,
subject to his or her continued employment through the applicable dates for such
bonuses:
 
     .    a bonus on the earliest of:

          (a)  the closing date of the Merger;
          (b)  the termination date of the Merger pursuant to the Merger
               Agreement; or
          (c)  September 18, 2000, if the Merger has not closed by then.

          in an amount equal to 150% of the sum of the Executive's base salary
          plus the Executive's targeted annual bonus, assuming all performance
          targets are met to the maximum extent, under COMSAT's Annual Incentive
          Plan; and

     .    a bonus on the eighteen month anniversary of the closing date of the
          Merger in an amount equal to 100% of the sum of the Executive's base
          salary plus the Executive's targeted annual bonus, assuming all
          performance targets are met to the maximum extent, under COMSAT's
          Annual Incentive Plan.

     In the following situations, the Executive will be entitled to receive, in
lieu of the retention bonuses described above, a payment in an amount equal to
the retention bonus to which the Executive would have been entitled had the
Executive remained employed by COMSAT through the applicable date:

                                       99
<PAGE>
 
     .    for termination without cause on or before the applicable date for
          such bonuses;

     .    by reason of the Executive's death or disability; or

     .    if the Executive elects to terminate his or her employment for good
          reason.

     If the Executive and Lockheed Martin are unable to reach an agreement
regarding the terms and conditions of the Executive's employment within 30 days
following the closing of the Merger and the Executive's employment is terminated
within such 30-day period, the Executive will:
 
     .    forfeit all rights to receive the bonus which otherwise would have
          been payable to the Executive on the eighteen month anniversary of the
          closing date of the Merger; or

     .    forfeit all rights to the payment in lieu of a bonus which would have
          been payable to the Executive in the event of a termination of the
          Executive's employment between the closing date of the Merger and the
          eighteen month anniversary of the closing date of the Merger.

     The amendments amended the employment agreements to provide that each of
the Executives will be entitled to receive the severance benefits and payments
to which he or she was entitled under his or her employment agreement prior to
the amendments only in the event that the termination of his or her employment
which gives rise to such payments occurs prior to a change in control of COMSAT.

     Pursuant to the amendments, each of the employment agreements was also
amended to provide that, if a change in control of COMSAT occurs and the
Executive's employment is terminated during the period beginning on the date of
the change in control and ending on the last day of the Executive's employment
term (a) by COMSAT other than for cause or disability, or (b) by the Executive
for good reason, then, in lieu of any other severance payments or severance
benefits payable to the Executive under the employment agreements, the Executive
will be entitled to receive the following until the expiration of the
Executive's employment term:

     .    base salary;

     .    targeted annual bonus under COMSAT's Annual Incentive Plan; and

     .    continued group health and welfare plan benefits for the Executive
          and the Executive's dependents (subject to reduction under certain
          circumstances described in the amendments).

The Executive also will be entitled to receive benefits under COMSAT's Insurance
and Retirement Plan for Executives commencing as early as age 55 without any
actuarial reduction for early commencement of benefits.

     In addition, the amendments modified the employment agreements to provide
that if a change in control of COMSAT occurs and (i) if the Executive and
Lockheed Martin have negotiated in good faith but have been unable to reach an
agreement regarding the terms and conditions of the Executive's

                                      100
<PAGE>
 
employment within 30 days following the closing of the Merger and the
Executive's employment is terminated within the 30 day period, or (ii) if the
Executive continues to be employed until the expiration of the Executive's
employment term, then the Executive will be entitled to receive the benefits
under the Insurance and Retirement Plan for Executives noted above.

     Each of the Executives also would be entitled to receive a gross-up payment
if any payment or benefit to the Executive would constitute an "excess parachute
payment" under Section 280G of the Internal Revenue Code.

     The share amounts discussed in this section have been adjusted to give
effect to the Ascent spin-off to COMSAT shareholders on June 27, 1997 by
multiplying the number of shares or units held on that date by an adjustment
ratio of 1.2402.

Agreement With Former Executive Officer

     COMSAT and Mr. Jasmann entered into a three-year employment agreement dated
August 1, 1996 which includes the following terms:
 
     .    base salary of $240,000 per year, subject to increases at the
          discretion of COMSAT's Board; and

     .    guaranteed bonus of $130,000 for 1996 and annual bonuses thereafter
          based on performance measures determined by the Board's Compensation
          Committee with a target bonus equal to 40% of Mr. Jasmann's base
          salary.

     On August 1, 1996, Mr. Jasmann was granted (i) an option to purchase 12,402
shares of COMSAT's common stock at a price equal to the market value of the
stock on the grant date, which vests 25% after one year, another 25% after the
second year and the remaining 50% after the third year; and (ii) 6,201
restricted stock units which vest after three years.
 
     On February 2, 1998, Mr. Jasmann resigned pursuant to a provision of the
agreement which permitted him to terminate his employment if COMSAT failed to do
an initial public offering of COMSAT International by February 1, 1998.
Pursuant to this provision, Mr. Jasmann will continue to receive salary and an
annual bonus at the same rate as in effect on the date of his termination until
August 1, 1999.  His existing stock options, but not his restricted stock units,
will continue to vest during that period.

     The share amounts discussed in this section have been adjusted to give
effect to the Ascent spin-off to COMSAT shareholders on June 27, 1997 by
multiplying the number of shares or units held on that date by an adjustment
ratio of 1.2402.

                                      101
<PAGE>
 
                         CHANGE IN CONTROL ARRANGEMENTS

     Certain of COMSAT's benefit and compensation programs have provisions that
are intended to assure the continuity and stability of management and the Board
necessary to protect shareholders' interests, and to protect the rights of the
participants under those programs, in the event of a change in control of
COMSAT.  A change in control for this purpose is defined in the same manner as
described above under the caption "Directors Compensation - Non-Employee
Directors Stock Plan."  The following actions will take place upon the
occurrence of a change in control:
 
     .    the vesting of all stock options, RSAs, RSUs and PSUs will be
          accelerated under COMSAT's 1990 and 1995 Key Employee Stock Plans,
          Non-Employee Directors Stock Plan and Annual Incentive Plan;

     .    the deferred compensation accounts under COMSAT's Directors and
          Executives Deferred Compensation Plan, Annual Incentive Plan and Non-
          Employee Directors Stock Plan will become immediately payable;

     .    participants in the Split Dollar Life Insurance Plans for Directors
          and for Key Employees will receive fully-paid individual policies;

     .    directors will receive an immediate lump sum payment of their accrued
          benefits under the Directors Retirement Plan using present value
          assumptions; and

     .    participants in COMSAT's Insurance and Retirement Plan for Executives
          will become vested in their accrued benefits under the plan and will
          receive an immediate lump sum payment using present value assumptions.

     The Board of Directors retains the authority under the change in control
provisions to determine that the provisions should not apply to a particular
transaction.  In the event of such a determination, the vesting of stock awards
and the payment of various plan benefits would not be accelerated.  This feature
is intended to afford the Board of Directors flexibility in structuring
transactions and to encourage negotiated transactions.
 
     Pursuant to such authority, the Board has adopted resolutions determining
that, for purposes of the Insurance and Retirement Plan for Executives, the
Deferred Compensation Plan, the Split Dollar Life Insurance Plan for Directors,
the Split Dollar Life Insurance Plan for Key Employees and the Annual Incentive
Plan, the Merger with Lockheed Martin Corporation and the transactions
contemplated by the Merger Agreement will not constitute a change in control of
COMSAT.  For purposes of the 1990 Key Employee Stock Plan, the 1995 Key Employee
Stock Plan, the Non-Employee Directors Stock Plan and the Amended and Restated
Change in Control Severance Plan, only the closing of the Merger with Lockheed
Martin Corporation, and not any of the other transactions contemplated by the
Merger Agreement, will constitute a change in control of COMSAT.

                                      102
<PAGE>
 
            COMPENSATION COMMITTEE INTERLOCKS, INSIDER PARTICIPATION
                         AND RELATED PARTY TRANSACTIONS
                                        
     The following directors of the Corporation, who are also members of the
Compensation Committee of the Board of Directors, may be deemed to have a
relationship with Lockheed Martin Corporation that may constitute an indirect
material interest in the proposed merger between the Corporation and Lockheed
Martin.  See "Item 7: Management's Discussion and Analysis of Financial
Condition and Results of Operations - Business Combination with Lockheed Martin
Corporation."
 
     Standard Technology, Inc., a technology, engineering and systems
integration firm, has provided services to Lockheed Martin under various
contracts, which resulted from arms's-length negotiations, in connection with a
Department of Defense mentor-protege program to encourage large defense
contractors to subcontract with minority-owned businesses.  Kathryn C. Turner, a
director of COMSAT since August 1997, is the Chairperson, Chief Executive
Officer and sole shareholder of Standard Technology. Lockheed Martin paid
Standard Technology $1,807,711, $2,008,766, $1,846,662 and $2,242,126 in 1998,
1997, 1996 and 1995, respectively, under those contracts.  Pursuant to the 
mentor-protege program, Lockheed Martin agreed to award Standard Technology
with a targeted amount of $1 million of contracts per year through 2001.
Pursuant to the mentor-protege program, Lockheed Martin also participates on an
ad hoc advisory board which provides guidance on business matters and has
provided financial assistance to Standard Technology.  Lockheed Martin has made
an unsecured loan to Standard Technology, which is repayable over a fifteen
year period commencing upon the earlier of 2007 or the year after Standard
Technology achieves annual revenues in excess of $25 million.  As of March 1,
1999, the outstanding balance of the loan was $2,632,166, which includes
previously capitalized interest. Interest does not currently accrue on the loan
but will accrue at 8% per annum on the unpaid principal amount once repayment is
required. In addition, Lockheed Martin has guaranteed up to $2 million of
Standard Technology's borrowings under a line of credit with a commercial bank,
which also is secured by Standard Technology's accounts receivable and a
personal guarantee by Ms. Turner.

     Pursuant to a continuing engagement, the law firm of  Wunder, Knight,
Levine, Thelen & Forscey has provided Lockheed Martin general legislative
support.  Peter S. Knight, a Presidentially-appointed director of the
Corporation since September 1994 and partner in the law firm of Wunder, Knight,
Levine, Thelen & Forscey, has rendered services to Lockheed Martin pursuant to
such engagement.  Lockheed Martin paid Wunder, Knight, Levine, Thelen & Forscey
$161,669, $112,129, $135,325 and $151,370 for services rendered and expenses
incurred during 1998, 1997, 1996 and 1995, respectively.

     Caleb B. Hurtt, a director of the Corporation since May 1996 and a director
of Lockheed Martin, may be deemed to have beneficial ownership of 5,672 shares
of Lockheed Martin common stock as of March 1, 1999.  He also had 1,013 phantom
stock units credited to an account in a Lockheed Martin deferred compensation
plan as of March 1, 1999.

                                      103
<PAGE>
 
    COMMITTEE ON COMPENSATION AND MANAGEMENT DEVELOPMENT REPORT ON EXECUTIVE
                                  COMPENSATION
                                        
     The Committee on Compensation and Management Development, which is composed
of independent outside directors, is responsible for establishing and
administering the Corporation's executive compensation philosophy.  Set forth
below is the Committee's report on the 1998 compensation of the executive
officers of the Corporation, including Mrs. Alewine, the Chief Executive
Officer, and the other executive officers named in the Summary Compensation
Table (the Named Executive Officers).

     The Corporation's executive compensation philosophy is designed to attract,
motivate and retain talented executives critical to the long-term success of the
Corporation.  One of the objectives of this philosophy is to align executive
compensation more closely with the interests of shareholders through performance
incentives.  The main components of this philosophy are annual compensation,
consisting of salary plus bonuses awarded under the Corporation's Annual
Incentive Plan, and long-term compensation, consisting of stock-based
incentives.  The Committee reviews and recommends to the Board the annual
compensation of all executive officers, and reviews and approves executive
officers' long-term compensation.

     There are two groups of competitive companies that are used in the
executive compensation analysis.  The first group, consisting of the companies
that make up the Peer Group Index discussed under the caption "Performance
Graph," is used to compare executive compensation strategy and practices.  The
second group, consisting of companies in the telecommunications industry with
revenues comparable to the Corporation's, is used to benchmark competitive
compensation levels.

Annual Compensation

     Mrs. Alewine has an employment agreement as Chief Executive Officer dated
July 19, 1996 which is summarized under the caption "Agreements with Current
Executive Officers."  Pursuant to the agreement, Mrs. Alewine received a base
salary of $450,000 for the first year and an increase to $500,000 beginning in
the second year.  In July 1998, the Committee recommended to the Board that Mrs.
Alewine's base salary be increased to $575,000 based on market data for a
comparable Chief Executive Officer position and her performance in the last
year.  The Board approved the Committee's recommendation.  Mrs. Alewine's
employment agreement specifies an annual bonus target of 70% of her base salary.
In addition, the agreement provides for the Committee to determine the
performance measures and other factors used to determine her bonus in
consultation with Mrs. Alewine.  These factors included the Corporation's
financial results, Mrs. Alewine's success in meeting personal objectives for
1998 which she presented to the Committee and the Corporation's achievement of
strategic objectives. These strategic objectives included the merger agreement
with Lockheed Martin Corporation, deregulation of the Corporation's largest
business unit, completion of the restructuring commenced in 1997 with the sale
of the Corporation's manufacturing unit, avoidance of adverse proposed
legislation in the 105/th/ Congress, and rapid progress in the privatizations of
INTELSAT and Inmarsat, the two global satellite consortia in which the
Corporation is the U.S. owner, including the spin-off of twenty five percent of
INTELSAT's satellite fleet into a new commercial company named New Skies
Satellites.  The Committee considered all of these factors in arriving at a
bonus recommendation for Mrs. Alewine.  The Committee recommended, and the Board
approved, payment of a 1998 cash bonus award of $400,000 for Mrs. Alewine.

                                      104
<PAGE>
 
     Base salary ranges have been established for the other executive officers
based on the average of the market for comparable positions in the revenue group
of competitive companies.  Individual salaries within each range are based on
recommendations to the Committee by the Chief Executive Officer taking into
account such factors as total professional experience, performance, and
experience in the current assignment.  The bonus opportunities for other
executive officers for 1998 were based on a range of award percentages of base
salary for each position determined by the Committee.  A portion of each bonus
award was tied to corporate performance criteria based on the achievement of
financial measures as compared to planned performance, and individual
performance criteria based on the Committee's evaluation of each individual
executive officer's achievement of established performance goals for the year.
The Committee recommended a bonus award for each executive officer based on a
bonus range and the performance measures noted above.  The Board had final
approval authority for these awards. Mr. Jasmann, who resigned as an executive
officer in February 1998, received the same bonus as he did the prior year in
accordance with the terms of his employment agreement with the Corporation,
which expires on August 1, 1999.

Long-Term Compensation

     Long-term compensation is an integral element of the Corporation's
executive compensation philosophy because the Committee believes that stock
ownership by senior management and stock-based performance-compensation
arrangements enhance shareholder value.  The Corporation's long-term
compensation strategy includes a blend of stock compensation.  For 1998, awards
by the Committee consisted of non-qualified stock options and restricted stock
awards (RSAs).  These awards were consistent with ranges in the revenue group of
competitive companies approved by the Committee.  The stock option ranges
position the Corporation at the median of the market for these companies while
the performance-based restricted stock awards allow for total long-term
compensation to reach the 75th percentile for this market if the business
achieves prescribed performance standards over the long term. At the Committee's
request, an independent executive compensation consultant conducted a review of
total compensation for Mrs. Alewine and the other Named Executive Officers which
included stock award recommendations.  The Committee endorsed the consultant's
methodology for developing recommendations for 1998 stock grants whereby base
salary, bonus and long-term compensation (stock option and restricted stock
awards) would be measured against market data on total compensation for
comparable positions.

     A portion of executive compensation is represented by stock options granted
at fair market value, which the Committee believes provide a tie to shareholder
interests.  In 1998, Mrs. Alewine received a grant of 30,000 stock options in
accordance with the methodology approved by the Committee.
 
     Stock options were granted to the other Named Executive Officers in
February 1998 as reflected in the table above setting forth 1998 option grants.
These stock option awards were determined on the basis of two factors.  First,
the Committee established target award guidelines for each executive officer
based on a competitive analysis of total compensation for each executive
officer.  Second, the Committee approved the actual awards for each executive
officer based on these guidelines and performance recommendations made by Mrs.
Alewine based on her evaluation of each officer's performance for 1997.

                                      105
<PAGE>
 
     RSAs are restricted shares of COMSAT stock which are granted to executive
officers and selected key employees as a performance incentive and a retention
device based on the vesting schedule established by the Committee for each
grant.  The vesting of RSAs is subject to both a length of service requirement
and the achievement of objective performance-based criteria which have been
approved by the Committee.  The percent of the award earned is based on the
level of achievement of the performance objectives over the performance period
established by the Committee.  The RSAs earned then become subject to vesting
over an additional 1, 2 and 3 years at the rate of 20%, 40% and 40%,
respectively.  Mrs. Alewine received 6,000 RSAs in February 1998.  The other
Named Executive Officers also received RSAs in February 1998 as shown in the
Summary Compensation Table, the number of which in each case was consistent with
the guidelines approved by the Committee.

     The performance-based criteria applicable to RSAs are intended to ensure
the Federal tax deductibility under Section 162(m) of the Internal Revenue Code
of compensation paid to the Corporation's executive officers pursuant to RSAs.
The Corporation intends to preserve the tax deductibility under Section 162(m)
of all compensation paid to its executive officers.

Committee on Compensation and Management Development

Caleb B. Hurtt, Chairman
Neal B. Freeman
Peter S. Knight
Robert G. Schwartz
Kathryn C. Turner


PERFORMANCE GRAPH

     The following graph compares the cumulative total shareholder return for
the Corporation's Common Stock with the cumulative total return of the S&P 500
Stock Index and a Peer Group Index constructed by the Corporation for the five
fiscal years beginning on January 1, 1994 and ending on December 31, 1998.  The
Peer Group consists of three long-distance telecommunications companies (AT&T,
MCI WorldCom and Sprint), and the following satellite industry companies (the
years for which the returns of such companies have been included in the five-
year period are noted in parentheses): American Mobil Satellite Corporation (all
years), Asia Satellite Telecom (American Depository Receipts (ADRS) (1996-98),
British Sky Broadcasting Group (ADRS) (1995-98), Echostar Communications
Corporation (1996-98), Globalstar Telecommunications Ltd. (1996-98), Iridium
World Communications (1996-98), Loral Space and Communications Ltd. (1997-98),
PanAmSat Corporation (1996-98), PT Pasifik Satelit Nusantara (ADRS) (1996-98)
and U.S. Satellite Broadcasting Co. (1996-98).  Returns for MCI WorldCom use
WorldCom, Inc. data for all years and include MCI Corporation data for 1998.

                                      106
<PAGE>


             Comparison of Five-Year Cumulative Total Return Among
                  COMSAT, S & P 500 Index, & Peer Group Index
      (Assumes $100 Invested on December 31, 1993 & Dividends Reinvested)



 
                       [PERFORMANCE GRAPH APPEARS HERE]

<TABLE>
<CAPTION>

           COMSAT     S&P 500     Peer Group
<S>        <C>        <C>         <C>
1993        100         100          100
1994         65         101           95
1995         67         139          131
1996         92         171          140
1997        107         229          191
1998        160         294          277
</TABLE>


                                      107
<PAGE>
 
Item 12:  Security Ownership of Certain Beneficial Owners and Management

Beneficial Owners

     COMSAT has reviewed the Schedules 13G or 13D filed with the Securities and
Exchange Commission (SEC) as of March 1, 1999, the most recent practicable date
for such information. COMSAT believes that the following table includes a
complete list of the persons that beneficially owned more than 5% of COMSAT's
common stock on that date.
 
<TABLE>
<CAPTION>
- ---------------------------------------------------------------------------
                                          Amount and
                                            Nature
                                         of Beneficial
Name and Address of Beneficial Owner      Ownership(1)     Percent of Class
- ---------------------------------------------------------------------------
<S>                                     <C>                <C>
FMR Corp.(2)                                    3,975,812              7.56
- ---------------------------------------------------------------------------
Morgan Stanley Dean Witter & Co.(3)             3,355,632              6.38
- ---------------------------------------------------------------------------
</TABLE>

(1)  Each number in this column has been rounded to the nearest whole share.
(2)  FMR Corporation, a Massachusetts corporation, is located at 82 Devonshire
     Street, Boston, Massachusetts 02109.  FMR Corporation filed an amendment to
     its Schedule 13-D on February 25, 1999 reporting on a voluntary basis that
     FMR and Fidelity International Limited, a Bermuda company, may be deemed to
     have jointly owned as of that date a total of 3,975,812 shares of COMSAT
     common stock.
(3)  Morgan Stanley Dean Witter & Co., a Delaware corporation, is located at
     1585 Broadway, New York, New York 10036.  Morgan Stanley Dean Witter
     Investment Management Limited, organized under the laws of England, is a
     wholly-owned subsidiary of Morgan Stanley Dean Witter & Co. that is located
     at 25 Cabot Square, Canary Wharf, London E14 4QA, England.  The two
     companies filed a joint amendment to Schedule 13-G on February 10, 1999 in
     which it was reported that the two companies together beneficially owned an
     aggregate of 3,355,632 shares of COMSAT common stock. Of this amount,
     Morgan Stanley Dean Witter Investment Management Limited beneficially owned
     an aggregate of 3,204,637 shares of COMSAT common stock.

Management
 
     The following table sets forth information as of March 1, 1999, the most
recent practicable date for such information, regarding the beneficial ownership
of COMSAT's common stock by all directors, by each of the Named Executive
Officers, and by all directors and executive officers as a group.  Under the
rules of the SEC, beneficial ownership includes any shares over which an
individual has sole or shared voting or investment power, and also any shares
that the individual has the right to acquire within 60 days through the exercise
of any stock option or other right.

                                      108
<PAGE>
 
<TABLE>
<CAPTION>
- --------------------------------------------------------------------------------
                                                          Amount and Nature of
Name(1)                                                  Beneficial Ownership(2)
- --------------------------------------------------------------------------------
<S>                                                      <C>   
Betty C. Alewine                                                   393,138   (3)
- --------------------------------------------------------------------------------
Marcus C. Bennett                                                    2,480
- --------------------------------------------------------------------------------
Lucy Wilson Benson                                                  40,485
- --------------------------------------------------------------------------------
Edwin I. Colodny                                                    47,749
- --------------------------------------------------------------------------------
Lawrence S. Eagleburger                                             13,102
- --------------------------------------------------------------------------------
Allen E. Flower                                                    123,818   (4)
- --------------------------------------------------------------------------------
Neal B. Freeman                                                     32,165
- --------------------------------------------------------------------------------
Caleb B. Hurtt                                                       8,441
- --------------------------------------------------------------------------------
Dwight E. Jasmann                                                    9,474   (5)
- --------------------------------------------------------------------------------
Peter S. Knight                                                     13,402
- --------------------------------------------------------------------------------
Peter W. Likins                                                     38,335   (6)
- --------------------------------------------------------------------------------
Charles T. Manatt                                                   13,902
- --------------------------------------------------------------------------------
John H. Mattingly                                                   47,689   (7)
- --------------------------------------------------------------------------------
Benjamin A. Pontano                                                 48,703   (8)
- --------------------------------------------------------------------------------
Larry G. Schafran                                                    7,480   (9)
- --------------------------------------------------------------------------------
Robert G. Schwartz                                                  44,285
- --------------------------------------------------------------------------------
Kathryn C. Turner                                                    4,480
- --------------------------------------------------------------------------------
Guy P. Wyser-Pratte                                              2,020,780  (10)
- --------------------------------------------------------------------------------
Warren Y. Zeger                                                    171,781  (11)
- --------------------------------------------------------------------------------
All directors and executive officers as a group                  3,106,957  (12)
(22 persons)
- --------------------------------------------------------------------------------
</TABLE>

(1)  Unless otherwise indicated, each person has sole voting and investment
     power over the shares listed, and no director or executive officer
     beneficially owns more than 1.0% of the Corporation's Common Stock.
(2)  Each number in this column has been rounded to the nearest whole share.
     The following non-employee directors elected to defer receipt of their
     1,000 share annual retainer for 1998 and instead received phantom stock
     units which are not included in their beneficial ownership of COMSAT Common
     Stock:  Mr. Bennett; Mrs. Benson; Mr. Eagleburger; Mr. Hurtt; Mr. Knight;
     Mr. Manatt; and Mr. Schafran.  Beneficial ownership of COMSAT Common Stock
     includes shares that may be acquired within 60 days after March 1, 1999
     through the exercise of options as follows:  Mrs. Alewine, 274,432 shares;
     Mr. Bennett, 2,480 shares; Mrs. Benson, 37,205 shares; Mr. Colodny, 43,408
     shares; Mr. Eagleburger, 12,402 shares; Mr. Flower, 99,266 shares; Mr.
     Freeman, 29,765 shares; Mr. Hurtt, 7,441 shares; Mr. Jasmann, 7,752 shares;
     Mr. Knight, 12,402 shares; Dr. Likins, 31,005 shares; Mr. Manatt, 12,402
     shares; Mr. Mattingly, 33,524 shares; Dr. Pontano, 33,515 shares; Mr.
     Schafran, 2,480 shares; Mr. Schwartz, 34,725 shares; Ms. Turner, 2,480
     shares; Mr. Wyser-Pratte, 2,480 shares; Mr. Zeger, 149,052 shares; and all
     directors and executive officers as a group, 838,157 shares. The number of
     option shares and shares awarded under COMSAT benefit plans which are
     restricted against transfer that are included as beneficially owned have
     been adjusted to give effect to the Ascent spin-off to COMSAT shareholders
     on June 27, 1997.  All outstanding options and restricted shares held on
     that date were adjusted by multiplying the number of options or shares held
     by an adjustment ratio of 1.2402.
(3)  Includes 23,666 shares which are restricted against transfer and 1,534
     shares which are held in the Corporation's Savings and Profit-Sharing Plan
     as of March 1, 1999.
(4)  Includes 12,957 shares which are restricted against transfer and 1,275
     shares which are held in the Corporation's Savings and Profit-Sharing Plan
     as of March 1, 1999.
(5)  Includes 23 shares which are held in the Corporation's Savings and Profit-
     Sharing Plan as of March 1, 1999.  Mr. Jasmann resigned in February 1998.
(6)  Includes 2,850 shares over which Dr. Likins shares voting power and
     investment power with Mrs. Likins.
(7)  Includes 7,984 shares which are restricted against transfer and 1,080
     shares which are held in the Corporation's Savings and Profit-Sharing Plan
     as of March 1, 1999.  Includes 500 shares held by Mr. Mattingly's mother of
     which Mr. Mattingly disclaims beneficial ownership.
(8)  Includes 4,000 shares which are restricted against transfer and 597 shares
     which are held in the Corporation's Savings and Profit-Sharing Plan as of
     March 1, 1999.
(9)  Includes 5,000 shares held by Mrs. Schafran of which Mr. Schafran disclaims
     beneficial ownership.
(10) Includes 1,961,300 shares owned by investment partnerships and other
     managed accounts for which Wyser-Pratte Management Co., Inc. and its
     affiliates are the general partner or investment manager.  Mr. Wyser-Pratte
     beneficially owned 3.84% of the Corporation's outstanding Common Stock as
     of March 1, 1999.
(11) Includes 13,453 shares which are restricted against transfer and 1,439
     shares which are held in the Corporation's Savings and Profit-Sharing Plan
     as of March 1, 1999.
(12) Includes 5,500 shares with respect to which beneficial ownership is
     disclaimed.  Also includes an aggregate of 70,056 shares which are
     restricted against transfer and 6,379 shares which are held in the
     Corporation's Savings and Profit-Sharing Plan as of March 1, 1999.  All
     directors and executive officers as a group beneficially owned 5.90% of the
     Corporation's outstanding Common Stock as of March 1, 1999.

                                      109
<PAGE>
 
Changes in Control
 
     The Corporation has entered into an Agreement and Plan of Merger, dated as
of September 18, 1998, by and among the Corporation, Lockheed Martin
Corporation, a Maryland corporation, and Deneb Corporation, a Delaware
corporation which is a wholly-owned subsidiary of Lockheed Martin.  For a
description of the transaction see "Item 7: Management's Discussion and Analysis
of Financial Condition and Results of Operations - Business Combination with
Lockheed Martin" and Note 2 to the financial statements.

Item 13:  Certain Relationships and Related Transactions

     The following directors of the Corporation may be deemed to have a
relationship with Lockheed Martin Corporation that may constitute an indirect
material interest in the proposed merger between the Corporation and Lockheed
Martin Corporation.  See "Item 7: Management's Discussion and Analysis of
Financial Condition and Results of Operations - Business Combination with
Lockheed Martin."

     For a discussion of certain relationships between Lockheed Martin
Corporation and each of Ms. Turner, Mr. Hurtt and Mr. Knight, see "Item 11:
Executive Compensation - Compensation Committee Interlocks, Insider
Participation and Related Party Transactions."

     Marcus C. Bennett, a director of the Corporation since August 1997, and the
former Executive Vice President and Chief Financial Officer and a director of
Lockheed Martin, may be deemed to have beneficial ownership of 197,092 shares of
Lockheed Martin common stock as of March 1, 1999.  He also had 861 phantom stock
units credited to an account in a Lockheed Martin deferred compensation plan as
of March 1, 1999.

     Edwin I. Colodny, the Chairman of the Board of COMSAT since April 1997 and
a director of the Corporation since May 1992, may be deemed to have beneficial
ownership of 4,204 shares of Lockheed Martin common stock as of March 1, 1999.

     Pursuant to a continuing engagement, the law firm of Manatt, Phelps &
Phillips, LLP has provided Lockheed Martin general legal and legislative
advocacy services in connection with government contracts and contracting
opportunities in the state of California.  Charles T. Manatt, a Presidentially-
appointed director of the Corporation since May 1995 and chairman of the law
firm of Manatt, Phelps & Phillips, LLP, has not had any personal involvement
with the services rendered pursuant to the engagement.  Lockheed Martin paid
Manatt, Phelps & Phillips, LLP $65,414, $166,113, $153,126 and $66,686 for
services rendered and expenses incurred during 1998, 1997, 1996 and 1995,
respectively.

                                      110
<PAGE>
 
                                    PART IV

Item 14:  Exhibits, Financial Statement Schedules, and Reports on Form 8-K

(a)  Documents filed as part of this Report

1.   Consolidated Financial Statements and Supplementary Data of Registrant
     a.  Independent Auditors' Report
     b.  Consolidated Financial Statements of COMSAT Corporation and
         Subsidiaries
         (i)   Consolidated Income Statements for the Years Ended December 31,
               1998, 1997 and 1996
         (ii)  Consolidated Balance Sheets as of December 31, 1998 and 1997
         (iii) Consolidated Cash Flow Statements for the Years Ended December
               31, 1998, 1997 and 1996
         (iv)  Statements of Changes in Consolidated Stockholders' Equity for
               the Years Ended December 31, 1998, 1997 and 1996
         (v)   Notes to Consolidated Financial Statements for the Years Ended
               December 31, 1998, 1997 and 1996

2.   Financial Statement Schedule Relating to the Consolidated Financial
     Statements of COMSAT Corporation for Each of the Three Years in the Period
     Ended December 31, 1998

     (a) Schedule II - Valuation and Qualifying Accounts

     All other Schedules have been omitted because they are not applicable or
not required or because the required information is included elsewhere in the
financial statements in this filing.

3.   Exhibits (listed according to the number assigned in the table in Item 601
     of Regulation S-K)

Exhibit No. 2 - Plan of Acquisition, Reorganization, Arrangement, Liquidation or
Succession

2.1  Agreement and Plan of Merger, dated as of September 18, 1998, among COMSAT
     Corporation, Lockheed Martin Corporation and Deneb Corporation
     (Incorporated by reference to Exhibit 2 to Registrant's
     Solicitation/Recommendation Statement on Schedule 14D-9 filed on September
     25, 1998)

2.2  Carrier Acquisition Agreement, dated as of September 18, 1998, by and among
     COMSAT Corporation, Lockheed Martin Corporation, Regulus, LLC, and COMSAT
     Government Systems, Inc.  (Incorporated by reference to Exhibit 5 to
     Registrant's Solicitation/Recommendation Statement on Schedule 14D-9 filed
     on September 25, 1998)

Exhibit No. 3 - Articles of Incorporation and By-laws

3.1  Articles of Incorporation of Registrant, composite copy, as amended through
     June 1, 1993 (Incorporated by reference from Exhibit No. 4(a) to
     Registrant's Registration Statement on Form S-3 (No. 33-51661) filed on
     December 22, 1993)

                                      111
<PAGE>
 
3.2  By-laws of Registrant, as amended through April 21, 1997 (Incorporated by
     reference from Exhibit No. 3.2 to Registrant's Current Report on Form 8-K
     filed on April 21, 1997.

3.3  Regulations adopted by Registrant's Board of Directors pursuant to Section
     5.02(c)f Registrant's Articles of Incorporation (Incorporated by reference
     from Exhibit No. 3(c) to Registrant's Report on Form 10-K for the fiscal
     year ended 1992)

Exhibit No. 4 - Instruments defining the rights of security holders, including
indentures

4.1  Specimen of a certificate representing Series I shares of COMSAT Common
     Stock, without par value, which are held by citizens of the United States
     (Incorporated by reference from Exhibit No. 4(a) to Registrant's Report on
     Form 10-K for the fiscal year ended December 31, 1993)

4.2  Specimen of a certificate representing Series I shares of COMSAT Common
     Stock, without par value, which are held by aliens (Incorporated by
     reference from Exhibit No. 4(b) to Registrant's Report on Form 10-K for the
     fiscal year ended December 31, 1982)

4.3  Specimen of a certificate representing Series II shares of COMSAT Common
     Stock, without par value (Incorporated by reference from Exhibit No. 4(c)
     to Registrant's Report on Form 10-K for the fiscal year ended December 31,
     1982)

4.4  Standard Multiple-Series Indenture Provisions dated March 15, 1991
     (Incorporated by reference from Exhibit No. 4(a) to Registrant's
     Registration Statement on Form S-3 (No. 33-39472) filed on March 15, 1991)

4.5  Indenture dated as of March 15, 1991 between Registrant and The Chase
     Manhattan  Bank, N.A. (Incorporated by reference from Exhibit No. 4(b) to
     Registrant's Registration Statement on Form S-3 (No. 33-39472) filed on
     March 15, 1991)

4.6  Supplemental Indenture, dated as of June 29, 1994, from the Registrant to
     The Chase Manhattan Bank, N. A. (Incorporated by reference from Exhibit No.
     4(c) to Registrant's Registration Statement on Form S-3 (No. 33-54369)
     filed on June 30, 1994)

4.7  Officers' Certificate pursuant to Section 3.01 of the Indenture, dated as
     of March 15, 1991, from the Registrant to The Chase Manhattan Bank, N.A.,
     as Trustee, relating to the authorization of $75,000,000 aggregate
     principal amount of Registrant's 8.95% Notes Due 2001 (with form of Note
     attached) (Incorporated by reference from Exhibit No. 4 to Registrant's
     Current Report on Form 8-K filed on May 15, 1991)

4.8  Officers' Certificate pursuant to Section 3.01 of the Indenture, dated as
     of March 15, 1991, from the Registrant to The Chase Manhattan Bank, N.A.,
     as Trustee, relating to the authorization of $160,000,000 aggregate
     principal amount of Registrant's 8.125% Debentures Due 2004 (with form of
     Debenture attached) (Incorporated by reference from Exhibit No. 4 to
     Registrant's Current Report on Form 8-K filed on April 9, 1992)

                                      112
<PAGE>
 
4.9  Officers' Certificate pursuant to Section 3.01 of the Indenture, dated as
     of March 15, 1991, as supplemented by the Supplemental Indenture, dated as
     of June 29, 1994, from the Registrant to The Chase Manhattan Bank, N.A., as
     Trustee, relating to the authorization of $100,000,000 aggregate principal
     amount of Registrant's Medium Term Notes, Series A (with forms of Notes
     attached) (Incorporated by reference from Exhibit No. 4(I) to Registrant's
     Report on Form 10-K for the fiscal year ended December 31, 1994)

4.10 Limited Partnership Agreement of COMSAT Capital I, L.P., dated as of July
     18, 1995, relating to issuance of monthly income preferred securities
     (Incorporated by reference from Exhibit No. 4(a) to Registrant's Report on
     Form 10-Q for the quarter ended June 30, 1995)

4.11 Guarantee Agreement for Preferred Securities of COMSAT Capital I, L.P.,
     dated as of July 18, 1995 (Incorporated by reference from Exhibit No. 4(b)
     to Registrant's Report on Form 10-Q for the quarter ended June 30, 1995)

4.12 Indenture between Registrant and the First National Bank of Chicago, as
     Trustee, dated as of July 18, 1995 (Incorporated by reference from Exhibit
     No. 4(c)  to Registrant's Report on Form 10-Q for the quarter ended June
     30, 1995)

Exhibit No. 10 - Material Contracts

10.1 Agreement relating to the International Telecommunications Satellite
     Organization (INTELSAT) by Governments, which entered into force on
     February 12, 1973 (Incorporated by reference from Exhibit No. 10(a) to
     Registrant's Report on Form 10-K for the fiscal year ended December 31,
     1980)

10.2 Operating Agreement relating to INTELSAT by Governments which entered into
     force on February 12, 1973 (Incorporated by reference from Exhibit No.
     10(b) to Registrant's Report on Form 10-K for the fiscal year ended
     December 31, 1980)

10.3 Agreement dated August 15, 1975, among COMSAT General Corporation, RCA
     Global Communications, Inc., Western Union International, Inc. and ITT
     World Communications, Inc. relating to the establishment of a joint venture
     for the purpose of participating in the ownership and operation of a
     maritime communications satellite system and Amendment Nos. 1-4 and
     Amendment No. 5 dated March 24, 1980 (Incorporated by reference from
     Exhibit No. 10(p) to Registrant's Report on Form 10-K for the fiscal year
     ended December 31, 1980)

10.4 Amendment No. 6 to Exhibit 10.3 dated September 1, 1981 (Incorporated by
     reference from Exhibit No. 10(p)(ii) to Registrant's Report on Form 10-K
     for the fiscal year ended December 31, 1981)

10.5 Convention on the International Maritime Satellite Organization (Inmarsat)
     dated September 3, 1976 (Incorporated by reference from Exhibit No. 11 to
     Registrant's Report on Form 10-K for the fiscal year ended December 31,
     1978)

                                      113
<PAGE>
 
10.6   Operating Agreement on Inmarsat dated September 3, 1976 (Incorporated by
       reference from Exhibit No. 12 to Registrant's Report on Form 10-K for the
       fiscal year ended December 31, 1978)

10.7*  Registrant's 1982 Stock Option Plan (Incorporated by reference from
       Exhibit No. 10(x) to Registrant's Report on Form 10-K for the fiscal year
       ended December 31, 1981)

10.8*  Registrant's Insurance and Retirement Plan for Executives, as amended and
       restated effective January 1, 1997 (Incorporated by reference from
       Exhibit No. 10.10 to Registrant's Report on Form 10-K for the fiscal year
       ended December 31, 1997)

10.9*  Registrant's Non-Employee Directors Stock Plan (Incorporated by reference
       from Exhibit No. 10.11 to Registrant's Report on Form 10-K for the fiscal
       year ended December 31, 1996)

10.10  Agreement to Acquire and Lease (and Supplemental Agreements thereto)
       dated September 28 and October 10, 1988, respectively, among the
       International Maritime Satellite Organization (Inmarsat), the North Sea
       Marine Leasing Company, British Aerospace Public Limited Company, the
       European Investment Bank, Kreditanstalt Fuer Wiederaufbau, European
       Investment Bank (as Agent and as Trustee), Instituto Mobiliare Italiano,
       Credit National, Hellenic Industrial Development Bank, and Society
       Nationale de Credit a L'Industrie relating to the financing of three
       Inmarsat spacecraft (Incorporated by Reference from Exhibit No. 3(a) to
       Registrant's Report on Form 10-K for the fiscal year ended December 31,
       1988)

10.11* Registrant's 1990 Key Employee Stock Plan (Incorporated by reference from
       Exhibit No. 10 (p) to Registrant's Report on Form 10-K for the fiscal
       year ended December 31, 1989)

10.12  Amended and Restated Agreement, dated November 14, 1990, of Limited
       Partnership of Rock Spring II Limited Partnership (Incorporated by
       reference from Exhibit No. 10(a) to Registrant's Current Report on
       Form 8-K filed on February 24, 1992)

10.13  Amended and Restated Lease Agreement, dated November 14, 1990, of Limited
       Partnership of Rock Spring II Limited Partnership (Incorporated by
       reference from Exhibit No. 10(b) to Registrant's Current Report on Form
       8-K filed on February 24, 1992)

10.14  Amended and Restated Ground Lease Indenture, dated November 14, 1990,
       between Anne D. Camalier (Landlord) and Rock Spring II Limited
       Partnership (Tenant) (Incorporated by reference from Exhibit No. 10(c) to
       Registrant's Current Report on Form 8-K filed on February 24, 1992)

10.15  Finance Facility Contract (and Supplemental Agreements thereto), dated
       December 20, 1991, among the International Maritime Satellite
       Organization (Inmarsat), Abbey National plc, General Electric Technical
       Services Company, Inc., European Investment Bank, Kreditanstalt Fuer
       Wiederaufbau, Instituto Mobiliare Italiano S.p.A., Credit National,
       Societe Nationale de Credit a L'Industrie, Finansieringsinstituttet for
       Industri OG Haandvaerk A/S, De Nationale Investeringsbank NV, and
       Osterreichische Investitionkredit Aktiengesellschaft relating to the
       financing of three Inmarsat spacecraft (Incorporated by reference from
       Exhibit No. 10 (dd) to Registrant's Report on Form 10-K for the fiscal
       year ended December 31, 1991)

                                      114
<PAGE>
 
10.16* Registrant's Directors and Executives Deferred Compensation Plan, as
       amended by the Board of Directors on July 15, 1993 (Incorporated by
       reference from Exhibit No. 10.24 to the Registrant's Report on Form 10-K
       for the fiscal year ended December 31, 1996)

10.17  Fiscal Agency Agreement, dated as of August 6, 1992, between
       International Telecommunications Satellite Organization and Morgan
       Guaranty Trust Company of New York (Incorporated by reference from
       Exhibit No. 10 (dd) to Registrant's Report on Form 10-K for the fiscal
       year ended December 31, 1992)

10.18  Fiscal Agency Agreement, dated as of January 19, 1993, between
       International Telecommunications Satellite Organization and Morgan
       Guaranty Trust Company of New York (Incorporated by reference from
       Exhibit No. 10 (ee) to Registrant's Report on Form 10-K for the fiscal
       year ended December 31, 1992)

10.19  Agreement dated July 1, 1993, between Registrant and AT&T Easylink
       Services relating to exchange of telex traffic (Incorporated by reference
       from Exhibit No. 10(bb) to Registrant's Report on Form 10-K for the
       fiscal year ended December 31, 1993)

10.20  Agreement dated July 27, 1993, between the Registrant and American
       Telephone & Telegraph Company relating to utilization of space segment
       (Incorporated by reference from Exhibit No. 10(cc) to Registrant's Report
       on Form 10-K for the fiscal year ended December 31, 1993)

10.21  Amendment to Exhibit 10.20 dated as of December 1, 1995 (Incorporated by
       reference from Exhibit No. 10.34 to Registrant's Report on Form 10-K for
       the fiscal year ended December 31, 1995)

10.22  Amendment to Exhibit 10.20 dated as of January 8, 1997 (Incorporated by
       reference from Exhibit No. 10.32 to Registrant's Report on Form 10-K for
       the fiscal year ended December 31, 1996)

10.23  Agreement dated November 6, 1998, between Registrant and MCI
       International, Inc. relating to exchange of traffic.

10.24  Agreement dated November 30, 1993, between the Registrant and Sprint
       Communications Company L.P. relating to utilization of space segment
       (Incorporated by reference from Exhibit No. 10(ee) to Registrant's Report
       on Form 10-K for the fiscal year ended December 31, 1993)

10.25  Amendment to Exhibit 10.24 dated April 7, 1995 (Incorporated by reference
       from Exhibit No. 10(a)(i) to Registrant's Report on Form 10-Q/A Amendment
       No. 2 dated June 29, 1995 for the quarter ended March 31, 1995)

10.26  Agreement dated December 10, 1993, between Registrant and Sprint
       International relating to the exchange of traffic (Incorporated by
       reference from Exhibit No. 10(ff) to Registrant's Report on Form 10-K for
       the fiscal year ended December 31, 1993)

10.27  Credit Agreement dated as of December 17, 1993 among Registrant,
       NationsBank of North Carolina, N.A., Bank of America National Trust and
       Savings Association, The First National

                                      115
<PAGE>
 
       Bank of Chicago, The Chase Manhattan Bank, N.A., The Sumitomo Bank,
       Limited, New York Branch, Swiss Bank Corporation, New York Branch, as
       lenders, and NationsBank of North Carolina, N.A., as agent (Incorporated
       by reference from Exhibit No. 10(gg) to Registrant's Report on Form 10-K
       for the fiscal year ended December 31, 1993)

10.28  Amendment No. 1 to Exhibit 10.27 dated as of December 17, 1994
       (Incorporated by reference from Exhibit No. 10(cc)(i) to Registrant's
       Report on Form 10-K for the fiscal year ended December 31, 1994)

10.29  Agreement dated January 24, 1994, between MCI International, Inc. and
       Registrant relating to utilization of space segment (Incorporated by
       reference from Exhibit No. 10(ii) to Registrant's Report on Form 10-K for
       the fiscal year ended December 31, 1993)

10.30  Amendment to Exhibit 10.29 dated as of July 1, 1995 (Incorporated by
       reference from Exhibit No. 10.42 to Registrant's Report on Form 10-K for
       the fiscal year ended December 31, 1995)

10.31  Amendment to Exhibit 10.29 dated as of September 17, 1996 (Incorporated
       by reference from Exhibit No. 10.41 to Registrant's Report on Form 10-K
       for the fiscal year ended December 31, 1996)

10.32  Agreement dated June 1, 1996, between Registrant and AT&T relating to
       exchange of traffic.

10.33  Fiscal Agency Agreement between International Telecommunications
       Satellite Organization, Issuer, and Bankers Trust Company, Fiscal Agent
       and Principal Paying Agent, dated as of March 22, 1994 (Incorporated by
       reference from Exhibit No. 10(kk) to Registrant's Report on Form 10-K for
       the fiscal year ended December 31, 1993)

10.34  Distribution Agreement dated July 11, 1994 between Registrant and CS
       First Boston Corporation, Salomon Brothers Inc and Nationsbanc Capital
       Markets, Inc., as Distributors, of Registrant's Medium-Term Notes, Series
       A (Incorporated by reference from Exhibit No. 10(ff) to Registrant's
       Report on Form 10-K for the fiscal year ended December 31, 1994)

10.35  Fiscal Agency Agreement between International Telecommunications
       Satellite Organization, Issuer, and Morgan Guaranty Trust Company, Fiscal
       Agent and Principal Paying Agent, dated as of October 14, 1994
       (Incorporated by reference from Exhibit No. 10(gg) to Registrant's Report
       on Form 10-K for the fiscal year ended December 31, 1994)

10.36* Registrant's Annual Incentive Plan (Incorporated by reference from
       Exhibit No. 10(hh) to Registrant's Report on Form 10-K for the fiscal
       year ended December 31, 1994)

10.37  Fiscal Agency Agreement between International Telecommunications
       Satellite Organization, Issuer, and Morgan Guaranty Trust Company, Fiscal
       Agent and Principal Paying Agent, dated as of February 28, 1995
       (Incorporated by reference from Exhibit No. 10(ii) to Registrant's Report
       on Form 10-K for the fiscal year ended December 31, 1994)

                                      116
<PAGE>
 
10.38* Registrant's 1995 Key Employee Stock Plan (Incorporated by reference from
       Exhibit No. 10.51 to the Registrant's Report on Form 10-K for the fiscal
       year ended December 31, 1996)

10.39  Distribution Agreement, dated as of June 3, 1997, between the Registrant
       and Ascent (Incorporated by reference from Exhibit 10.2 to the
       Registrant's Report on Form 8-K dated June 18, 1997)

10.40  Tax Disaffiliation Agreement, dated as of June 3, 1997, between the
       Registrant and Ascent (Incorporated by reference from Exhibit 10.3 to the
       Registrant's Report on Form 8-K dated June 18, 1997)

10.41  Amended and Restated Employment Agreement, dated as of July 18, 1997,
       between the Registrant and Betty C. Alewine (Incorporated by reference
       from Exhibit 9 to the Registrant's Solicitation/Recommendation Statement
       on Schedule 14D-9 filed on September 25, 1998)

10.42  Amended and Restated Employment Agreement, dated as of July 18, 1997,
       between the Registrant and Allen E. Flower (Incorporated by reference
       from Exhibit 11 to the Registrant's Solicitation/Recommendation Statement
       on Schedule 14D-9 filed on September 25, 1998)

10.43  Amended and Restated Employment Agreement, dated as of July 18, 1997,
       between the Registrant and Warren Y. Zeger (Incorporated by reference
       from Exhibit 13 to the Registrant's Solicitation/Recommendation Statement
       on Schedule 14D-9 filed on September 25, 1998)

10.44  Shareholders' Agreement, dated as of September 18, 1998, between COMSAT
       Corporation and Lockheed Martin Corporation (Incorporated by reference to
       Exhibit 3 to the Registrant's Solicitation/Recommendation Statement on
       Schedule 14D-9 filed on September 25, 1998)

10.45  Registration Rights Agreement, dated as of September 18, 1998, between
       COMSAT Corporation and Lockheed Martin Corporation (Incorporated by
       reference to Exhibit 4 to the Registrant's Solicitation/Recommendation
       Statement on Schedule 14D-9 filed on September 25, 1998)

10.46  Amendment to Amended and Restated Employment Agreement, between COMSAT
       Corporation and Betty C. Alewine, dated as of September 18, 1998
       (Incorporated by reference to Exhibit 10 to the Registrant's
       Solicitation/Recommendation Statement on Schedule 14D-9 filed on
       September 25, 1998)

10.47  Amendment to Amended and Restated Employment Agreement, between COMSAT
       Corporation and Allen E. Flower, dated as of September 18, 1998
       (Incorporated by reference to Exhibit 12 to the Registrant's
       Solicitation/Recommendation Statement on Schedule 14D-9 filed on
       September 25, 1998)

10.48  Amendment to Amended and Restated Employment Agreement, between COMSAT
       Corporation and Warren Y. Zeger, dated as of September 18, 1998
       (Incorporated by reference to Exhibit 14 to the Registrant's
       Solicitation/Recommendation Statement on Schedule 14D-9 filed on
       September 25, 1998)

                                      117
<PAGE>
 
10.49  Stock Purchase and Sale Agreement, dated as of March 16, 1998 among
       COMSAT Corporation, TBG Industries, Inc. and Prodelin Holding Corporation
       (Incorporated by reference to Exhibit 10.1 to the Registrant's Report on
       Form 10-Q for the quarter ended March 31, 1998)

10.50  Master Lease Agreement by and between LCOR Clarksburg L.L.C., as
       Landlord, and COMSAT Corporation, as Tenant, dated as of September 12,
       1997.

10.51  Facilities Lease Agreement by and between LCOR Clarksburg L.L.C., as
       Landlord, and COMSAT Corporation, as Tenant, dated as of September 12,
       1997.

10.52  Agreement among COMSAT Corporation, COMSAT Argentina, S.A. and ICO Global
       Communications (Holdings) Limited, ICO Global Communications Holdings
       B.V. and ICO Global Communications Services Inc., dated as of September
       30, 1998.

10.53* COMSAT Corporation Retention Bonus Plan, effective as of September 18,
       1998 (Incorporated by reference to Exhibit 15 to the Registrant's
       Solicitation/Recommendation Statement on Schedule 14D-9 filed on
       September 18, 1998)

10.54* COMSAT Corporation Amended and Restated Change of Control Severance
       Plan, effective as of September 18, 1998 (Incorporated by reference to
       Exhibit 16 to the Registrant's Solicitation/Recommendation Statement on
       Schedule 14D-9 filed on September 18, 1998)

10.55* Amendment to COMSAT Corporation 1995 Key Employee Stock Plan, dated as of
       September 18, 1998 (Incorporated by reference to Exhibit 17 to the
       Registrant's Solicitation/Recommendation Statement on Schedule 14D-9
       filed on September 18, 1998

10.56* Amendment to COMSAT Corporation 1990 Key Employee Stock Plan, dated as of
       September 18, 1998 (Incorporated by reference to Exhibit 18 to the
       Registrant's Solicitation/Recommendation Statement on Schedule 14D-9
       filed on September 18, 1998

10.57* Amendment to COMSAT Corporation Non-Employee Directors Stock Plan, dated
       as of September 18, 1998 (Incorporated by reference to Exhibit 19 to the
       Registrant's Solicitation/Recommendation Statement on Schedule 14D-9
       filed on September 18, 1998
       
10.58* Amendment to COMSAT Corporation Directors and Executives Deferred
       Compensation Plan, dated as of September 18, 1998 (Incorporated by
       reference to Exhibit 20 to the Registrant's Solicitation/Recommendation
       Statement on Schedule 14D-9 filed on September 18, 1998

Exhibit No. 21 - Subsidiaries of the Registrant as of December 31, 1998

Exhibit No. 23 - Consents of experts and counsel

     Consent of Independent Auditors dated March 24, 1999.

                                      118
<PAGE>
 
Exhibit No. 27 - Financial Data Schedule

     (b)  Reports on Form 8-K

     The Corporation filed a Report on Form 8-K dated December 23, 1998, related
to the amicable resolution of a dispute between the Corporation and ICO Global
Communications (Holdings) Ltd.

*Compensatory plan or arrangement.

                                      119
<PAGE>
 
                                   SIGNATURES

     Pursuant to the requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934, the Registrant has duly caused this report to be signed on
its behalf by the undersigned, thereunto duly authorized.

                                    COMSAT CORPORATION
                                       (Registrant)

Date:  March 25, 1999               By /s/ Alan G. Korobov
                                       -----------------------------
                                       (Alan G. Korobov, Controller)

     Pursuant to the requirements of the Securities Exchange Act of 1934, this
report has been signed below by each of the following persons on behalf of the
Registrant and in the capacity and as of March 25, 1999.  Each person whose
signature appears below constitutes and appoints the Registrant's Vice President
and Chief Financial Officer, Vice President and General Counsel or Controller
his or her true and lawful attorney-in-fact, with full power of substitution,
for him or her and in his or her name, place and stead, in any and all
capacities, to sign any and all amendments to this Form 10-K, and to file the
same, with all exhibits thereto, and other documents in connection therewith,
with the Securities and Exchange Commission, hereby ratifying and confirming all
that said attorney-in-fact, or his substitute, may lawfully do or cause to be
done by virtue hereof.

                                    (1)  Principal executive officer
 
                                    By   /s/ Betty C. Alewine
                                         --------------------------------------
                                         (Betty C. Alewine, President and Chief
                                         Executive Officer and Director)
 

                                    (2)  Principal financial officer
 
                                    By   /s/ Allen E. Flower
                                         --------------------------------------
                                         (Allen E. Flower, Vice President and
                                         Chief Financial Officer)
 

                                    (3)  Principal accounting officer
 
                                    By   /s/ Alan G. Korobov
                                         --------------------------------------
                                         (Alan G. Korobov, Controller)

                                      120
<PAGE>
 
                                    (4)  Board of Directors
 
                                    By   /s/ Edwin I. Colodny
                                         --------------------------------------
                                         (Edwin I. Colodny, Chairman and
                                         Director)
 
 
                                    By   /s/ Marcus C. Bennett
                                         --------------------------------------
                                         (Marcus C. Bennett, Director)
 
 
                                    By   /s/ Lucy Wilson Benson
                                         --------------------------------------
                                         (Lucy Wilson Benson, Director)
 
 
                                    By   /s/ Lawrence S. Eagleburger
                                         --------------------------------------
                                         (Lawrence S. Eagleburger, Director)
 
 
                                    By   /s/ Neal B. Freeman
                                         --------------------------------------
                                         (Neal B. Freeman, Director)
 
 
                                    By   /s/ Caleb B. Hurtt
                                         --------------------------------------
                                         (Caleb B. Hurtt, Director)
 
 
                                    By   /s/ Peter S. Knight       
                                         --------------------------------------
                                         (Peter S. Knight, Director)
 
 
                                    By   /s/ Peter W. Likins
                                         --------------------------------------
                                         (Peter W. Likins, Director)
 
 
                                    By   /s/ Charles T. Manatt
                                         --------------------------------------
                                         (Charles T. Manatt, Director)
 

                                      121
<PAGE>
 
                                    By   /s/ Larry G. Schafran
                                         --------------------------------------
                                         (Larry G. Schafran, Director)
 
 
                                    By   /s/ Robert G. Schwartz
                                         --------------------------------------
                                         (Robert G. Schwartz, Director)
 
 
                                    By   /s/ Kathryn C. Turner
                                         --------------------------------------
                                         (Kathryn C. Turner, Director)
 
 
                                    By   /s/ Guy P. Wyser-Pratte
                                         --------------------------------------
                                         (Guy P. Wyser-Pratte, Director)

                                      122
<PAGE>
 
                      COMSAT CORPORATION AND SUBSIDIARIES
                SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS
              For the Years Ended December 31, 1998, 1997 and 1996

<TABLE>
<CAPTION>
                                              Balance at
                                              Beginning of  Charged to                 Balance at
In thousands                                     Year       Expenses    Deductions(a)  End of Year
- ---------------------------------------------------------------------------------------------------
<S>                                          <C>            <C>         <C>            <C>
1996:
Allowance for loss on accounts receivable        $ 8,251      $3,847      $  939          $11,159
Allowance for loss on investments                      -      $1,105           -          $ 1,105
 
1997:
Allowance for loss on accounts receivable        $11,159      $6,306      $2,730          $14,735
Allowance for loss on investments                $ 1,105      $1,008           -          $ 2,113
 
1998:
Allowance for loss on accounts receivable        $14,735      $4,749      $2,361          $17,123
Allowance for loss on investments                $ 2,113      $1,950           -          $ 4,063
</TABLE>

(a)  Uncollectible amounts written off, recoveries of amounts previously
     reserved, and other adjustments.

                                      123

<PAGE>
 
                                                                  EXHIBIT 10.23



                             SERVICE AGREEMENT

         This Service  Agreement (the "Agreement") is made and entered into
this 6th day of November 1998, by and between COMSAT Mobile Communications,
a business unit of COMSAT Corporation, a corporation organized and existing
under the laws of the  District of Columbia,  with offices  located at 6560
Rock  Spring  Drive,   Bethesda,   Maryland  20871   ("COMSAT"),   and  MCI
International, Inc., a corporation organized and existing under the laws of
Delaware,  with offices at 2 International Drive, Rye Brook, New York 10573
("MCI").  COMSAT and MCI are  hereinafter  collectively  referred to as the
"Parties" and individually referred to as a "Party".

WHEREAS,  COMSAT provides mobile satellite  communications  services to and
from  mobile  earth  stations  via  the   International   Mobile  Satellite
Organization  ("Inmarsat")  satellite  system  through  COMSAT's land earth
stations and switching facilities; and

WHEREAS,  MCI  maintains  a  terrestrial   telecommunications  network  and
provides telecommunication  services,  including telex services, within the
United States and abroad; and

WHEREAS,  both Parties desire to obtain the services of the other Party and
are willing to interconnect  facilities for the purpose of facilitating the
mutual  provision of services in accordance  with the terms and  conditions
set forth herein.

NOW, THEREFORE,  in consideration of the foregoing and the mutual covenants
herein expressed, COMSAT and MCI agree as follows:

1.       DEFINITIONS

1.1      "COMSAT  Facilities"  shall mean land earth  stations  ("LES") and
         switching facilities provided by COMSAT.

1.2      "COMSAT  Services" shall mean Standard-A,  -M, -B, Mini-M and Aero
         mobile satellite  communication  services to and from mobile earth
         stations  via  the  Inmarsat   satellite   system  through  COMSAT
         Facilities.

1.3      "Effective Date" shall mean November 1, 1998.

1.4      "Fixed-to-Mobile  Traffic" shall mean U.S. traffic  originating on
         MCI  Facilities in a fixed location and destined to terminate at a
         mobile earth station via the Inmarsat satellite system.

1.5      "Inmarsat  Ocean  Regions"  shall mean the  Pacific  Ocean  Region
         ("POR"),  the Atlantic Ocean Region-West  ("AOR-W"),  the Atlantic
         Ocean Region-East ("AOR-E") and the Indian Ocean Region ("IOR").

1.6      "MCI Facilities" shall mean MCI's international  switching centers
         and other terrestrial facilities owned or controlled by MCI or, as
         the case may be, the  facilities  of any local  exchange  carriers
         selected by MCI for the  termination of  Mobile-to-Fixed  Traffic.
         MCI's Facilities shall not include facilites owned and operated by
         Worldcom,  Inc. or its affiliates prior to the merger of Worldcom,
         Inc. and MCI Communications Corporation.

1.7      "MCI Services" shall mean terrestrial  communications  services to
         and from  fixed  international  or  domestic  land  points via MCI
         Facilities.

1.8      "MES" shall mean mobile earth station.

1.9      "Mobile-to-Fixed  Traffic" shall mean traffic  originating  from a
         mobile  earth  station  via  the  Inmarsat  satellite  system  and
         COMSAT's   Facilities   and  destined  to  terminate  at  a  fixed
         international or domestic land point.

1.10     "Transit   Traffic"   shall  mean   traffic  to  an  Inmarsat  MES
         originating  from a  fixed  location  in a  country  in  which  no
         Inmarsat land earth station exists to provide  service to such MES
         and  which  traffic  is  routed  over  MCI  Facilities  to  COMSAT
         Facilities for delivery to its final destination.
<PAGE>
 
2.       TERM OF AGREEMENT.

         Unless  otherwise  terminated  pursuant to Article 7 hereof,  this
         Agreement shall be effective for a period of one year,  commencing
         on the Effective Date ("Initial Term").

3        SERVICE PROVISION AND RATES

3.1      COMSAT shall provide COMSAT Services to MCI at the rates set forth
         in  Attachment  A hereto in order to allow MCI to  terminate  U.S.
         originated Fixed-to-Mobile Traffic. Notwithstanding the foregoing,
         COMSAT  shall  provide a  discount  to its rates for  Standard  -A
         services  in  consideration  of MCI's  commitment  to program  its
         switches and undertake any other  measures  necessary to direct to
         COMSAT a minimum of  seventy-five  (75%) of MCI's  U.S.-originated
         Inmarsat  -A, -M,  -B,  Mini-M  and Aero  Fixed-to-Mobile  Traffic
         destined to the AOR-E,  AOR-W and POR. The discount  rate shall be
         as set forth in  Attachment  A. In order to receive the  discount,
         internal  monthly  reviews shall be conducted by COMSAT to measure
         actual  Fixed-to-Mobile  traffic  delivered by MCI to COMSAT.  The
         rates set forth in  Attachment  A shall be  inclusive of all space
         and ground segment charges. COMSAT shall be solely responsible for
         such charges and MCI shall have no responsibility therefor.

3.2      MCI shall  provide  MCI  Services  to  COMSAT  to allow  COMSAT to
         terminate  Mobile-to-Fixed  Traffic  at the  rates  set  forth  in
         Attachment B hereto.  COMSAT  shall be eligible  for  discounts as
         described  in  Attachment  B. The rates set forth in  Attachment B
         shall be inclusive of all  pay-outs and other  amounts  payable to
         any local, long distance or other carrier or administration and/or
         other operating  entities with respect to MCI Service  terminating
         in or transiting through their jurisdictions.  MCI shall be solely
         responsible for settlements with and payments to such carriers and
         COMSAT shall have no responsibility therefor.

3.3      The rates set forth in Attachments A and B shall be effective as of 
         November 1, 1998.

3.4      Transit Traffic

3.4.1    For Transit Traffic,  COMSAT will establish transit rates with the
         foreign  administrations  for the LES  component of the charge and
         MCI will establish the international land line charges.

3.4.2    For Transit Traffic where the foreign administration  accounts and
         settles with COMSAT for the LES component  ("Direct  Settlement"),
         the foreign telephone administration shall account and settle with
         MCI for the  international  land line  charges.  In the event that
         cascade accounting is utilized, MCI shall credit COMSAT the amount
         due COMSAT and  settlement  shall be in  accordance  with  Section
         6.1.2. MCI shall provide  sufficient  detail on a monthly basis to
         enable COMSAT to determine the foreign  administration  from which
         the call originated,  volume and ocean region  destinations of the
         Transit Traffic.

4.       INTERCONNECTION OF FACILITIES.

4.1      COMSAT and MCI agree to  interconnect  COMSAT  Facilities  and MCI
         Facilities   to  permit  the  exchange  of   Fixed-to-Mobile   and
         Mobile-to-Fixed  Traffic. The points of interconnections  shall be
         at COMSAT's Main Distribution Frame ("MDF") at COMSAT's Facilities
         at Santa Paula, California and Southbury, Connecticut.

4.2      Each Party shall be responsible for providing and maintaining,  at
         its own expense and liability,  the equipment and circuits located
         on its  side  of the  MDF.  The  Parties  shall  cooperate  in the
         detection and  correction of problems which can not be immediately
         isolated to a specific side of the MDF or segment of a circuit.

4.3      Except as otherwise agreed by the Parties, the technical standards
         and methods of operation applied by the Parties in the exchange of
         traffic hereunder shall conform to the applicable  recommendations
         of the International Telecommunications Union - Telecommunications
         Standardization Sector ("ITU-T") and to any revisions of same. The
         Parties agree that the  signaling  standard  shall  continue to be
         Signaling System
<PAGE>
 
         No. 5.  Such signaling standard may be upgraded to Signaling System 
         No. 7 upon availability and mutual agreement of the Parties.

5.       APPLICABLE SERVICE STANDARDS

5.1      COMSAT  Services.  COMSAT shall provide  COMSAT  Services  through
         COMSAT   Facilities   which   satisfy  the   applicable   Inmarsat
         specifications for such services.  COMSAT's failure to comply with
         non-mandatory specifications shall not be deemed to be in conflict
         with this Agreement.

5.2      MCI Services.  MCI shall provide services through its facilities 
         which satisfy ITU Recommendations Q. 140 through Q. 157 for Signaling 
         System No. 5.

6.       PAYMENT FOR SERVICE

6.1      Accounting and Settlement Procedures.

6.1.1    Each Party shall be responsible  for  establishing  end-user rates
         for services  rendered to its respective  customers.  In addition,
         each  Party  shall  be  responsible  to bill and  collect  service
         charges from its respective customers.

6.1.2    No later  than  sixty  (60) days after the end of a service
         month, the Parties shall exchange  accounting  statements for services
         provided to each other during the preceding calendar month. Each Party
         shall  provide  to the  other  Party  such  detail  as each  Party may
         reasonably require to determine the appropriate settlement between the
         Parties. At a minimum, the monthly statement shall contain the type of
         service,  the Inmarsat Ocean Region,  the number of calls, the minutes
         carried  and  the  rates  applicable  to  each  minute.  Such  monthly
         statement   shall  be   provided   via  a  printed   statement   until
         implementation of settlement disk processing. The Parties shall reduce
         to a net  balance  the sum due in U.S.  Dollars  each  month from each
         Party to the other Party.  Net  balances  due from one Party  ("Debtor
         Party") to the other  Party  ("Creditor  Party")  shall be paid by the
         Debtor Party to the Creditor  Party.  Settlement of net balances shall
         be made  within  forty-five  (45) days of receipt of invoice  from the
         Creditor Party. The inability of a Party to collect from its end users
         shall not relieve such Party's obligation to make payment to the other
         Party for services rendered hereunder.

6.2      Billing  Disputes.  Each Party is responsible  for the accuracy of
         any  accounting  statement or invoice that it submits to the other
         Party.  An  accounting  statement  shall be  deemed  to have  been
         accepted  by the Party to whom it is  rendered  if such Party does
         not  object  in  writing  thereto  before  the  end of the  second
         calendar  month  following  the  month in  which  the  account  is
         transmitted by the Party rendering it. Agreed adjustments shall be
         included in the following monthly accounting statement. Objections
         to an invoice that are not raised within twelve (12) months of the
         date on which an invoice is  received  by a Party  shall be deemed
         waived by such Party and such invoice shall be deemed final.

6.3.1    Taxes.  Each  Party  shall be  responsible  for its own tax or tax
         related  surcharges  determined by reference to income, net worth,
         franchise  or property  and any other tax imposed  directly on the
         Party.

6.3.2    With regard to services  originated  and billed to a purchaser  by
         MCI,  MCI  agrees  to  be  responsible   for  the   determination,
         collection and remittance of all appropriate taxes imposed thereon
         including but not limited to United States federal  excise,  state
         and local sales,  gross receipts and similar taxes. With regard to
         services  originated  and billed to a purchaser by COMSAT,  COMSAT
         agrees to be  responsible  for the  determination,  collection and
         remittance of all appropriate  taxes imposed thereon including but
         not  limited  to United  States  federal  excise,  state and local
         sales, gross receipts and similar taxes.

         In the event that an exemption  certificate  is required by either
         Party, all efforts will be made to provide such certificate to the
         requesting Party.
<PAGE>
 
7.       TERMINATION.

7.1      Termination  . This  Agreement  may be  terminated by either Party
         ("Terminating  Party") to the other Party (the "Defaulting Party")
         in the event that one (1) or more of the  following  events  shall
         occur and which  event(s)  shall not have been  cured  within  the
         thirty  (30) day period  from the date of written  notice  thereof
         from the Terminating Party to the Defaulting Party: (a) failure of
         the  Defaulting  Party  to  pay  any  sum  due  and  owing  to the
         Terminating Party within the payment period specified in Section 6
         hereof;  or (b)  failure of the  Defaulting  Party to perform  any
         material obligation contained in this Agreement.

7.1.1    Consequence  of  Termination.  Termination  or  expiration of this
         Agreement  in  accordance  with its terms  shall not  release  the
         Parties hereto from any liability which at the time of termination
         or expiration has already  accrued or which  thereafter may accrue
         in  respect  of any  act or  omission  of a  Party  prior  to such
         termination  or  expiration,  or  from  any  obligation  which  is
         expressly  stated in this  Agreement  to  survive  termination  or
         expiration.

7.1.2    Upon expiration or termination of this Agreement:

         a.       Neither Party shall be obligated to provide its services to 
                  the other Party;

         b.       Each  Party  shall  return or  destroy  all  Confidential
                  Information of the other Party in its possession no later
                  than five (5) business days following the  termination or
                  expiration date; and

         c.       All mutual  indebtedness  of the Parties  that shall have
                  accrued as of the date of termination or expiration shall
                  become due and payable within thirty (30) days thereof.

8.       LIABILITY; GENERAL INDEMNITY

8.1      In no event  shall  either  Party be liable to the other Party for
         any special,  indirect,  incidental,  punitive,  consequential  or
         exemplary  damages,  including without limitation loss of revenue,
         loss of profits, loss of clients or goodwill arising in any manner
         from this  Agreement  and the  performance  or  nonperformance  of
         business hereunder.

8.2      With respect to the service that each Party  provides to the other
         Party hereunder,  neither Party shall be liable for, and expressly
         disclaims any liability to the other Party, its customers, assigns
         or any other person or entity for any damages, claims,  liability,
         expenses,  or loss,  regardless of the degree of fault or failure,
         including  but not  limited to damage to  property  and claims for
         personal  injury  or death,  sustained  by the  other  Party,  its
         customers,  assigns  or any other  person or entity for any reason
         relating  to  the  unavailability,  delay,  outage,  interruption,
         disruption,  break-down,  degradation,  error in transmission,  or
         failure arising out of, relating to, or in any way associated with
         the  Services,   satellites,   land  earth  stations,   equipment,
         operations,  or facilities that are involved in the performance of
         this  Agreement,  regardless of the cause or causes  thereof,  and
         regardless of whether or not  attributable to any negligent act or
         omission or whether or not such act or omission constitutes,  with
         respect  to any  person  or  entity,  failure  to meet  any of its
         obligations.

8.3      With respect to the COMSAT Services provided hereunder, MCI agrees
         that  Inmarsat  shall  not be  liable  to the same  extent  as the
         disclaimers of liability in this Article.

8.4      Each Party agrees to include, in any contract,  agreement,  tariff
         or  other  undertaking  between  it and  any  customer  or  assign
         relating to the  services,  operations,  equipment  or  facilities
         involved in the performance of this Agreement, a provision stating
         that the  disclaimers  of liability as set forth above shall apply
         in full to said contract, agreement, tariff or other undertaking.
<PAGE>
 
9.       FORCE MAJEURE

9.1      Except for payment obligations,  neither Party shall be liable for
         failure to perform under this  Agreement due to any act,  event or
         cause  beyond  its  reasonable  control  ("Force  Majeure  Event")
         including, but not limited to:

         Acts of God,  peril  of the  sea,  accident  of  navigation,  war,
         sabotage, riot, insurrection,  civil commotion, national emergency
         (whether in fact or by law), martial law, fire, lightning,  flood,
         cyclone,  earthquake,  landslide,  storm or other adverse  weather
         conditions,  explosion,  power  shortage,  strike  or other  labor
         difficulty (whether or not involving COMSAT employees),  epidemic,
         quarantine, radiation or radioactive contamination;

         Action or inaction of any government or other competent authority,
         (including  any  court  of  competent   jurisdiction),   including
         expropriation,  restraint, prohibition, intervention, requisition,
         requirement,  direction  or  embargo  by  legislation  regulation,
         decree or other legally enforceable order; and Breakdown of plant,
         machinery   or   equipment,    externally   caused    transmission
         interference or satellite failure,  or satellite launch failure or
         delay,   or   satellite   malfunction,   or  shortages  of  labor,
         transportation,  fuel,  power or plant,  machinery,  equipment  or
         material.

9.2      In the  event  that a Force  Majeure  Event  exceeds  thirty  (30)
         consecutive  days,  then following  such  thirty-day  period,  the
         Parties  shall meet and negotiate  the  continuation,  suspension,
         termination, restructuring or other disposition of this Agreement.
         Upon  removal  or  cessation  of  the  Force  Majeure  Event,  all
         obligations under this Agreement shall resume,  unless the Parties
         determine to terminate or restructure the Agreement.

10.      ASSIGNMENT

         This  Agreement  shall not be  assigned or  transferred  by either
         Party without the prior written consent of the other Party,  which
         consent   shall  not  be   unreasonably   withheld   or   delayed.
         Notwithstanding  the  foregoing,  either  Party may,  without  the
         other's  consent,  make an assignment  to a successor,  affiliate,
         subsidiary, or to any entity controlling or under the same control
         as such a Party.

11.      GOVERNMENT APPROVALS

11.1     All agreements covenants, undertakings and obligations herein made
         or assumed by the Parties  hereto are subject to the  obtaining of
         all   necessary   governmental   licenses,    consents,   permits,
         authorizations,   and  approvals.  Each  Party  shall  obtain  and
         continue   to   maintain   such   licenses,   consents,   permits,
         authorizations, and approvals.

11.2     Both Parties  represent and warrant that they have been authorized
         as common  carriers  by the FCC  pursuant  to  Section  214 of the
         Communication  Act of 1934, as amended.  A copy of this  Agreement
         shall be filed with the FCC  pursuant  to Section  211 of such Act
         and shall seek confidential treatment of such filing.

12.      CONFIDENTIALITY

12.1     The  Parties  hereby  agree  that  it  may  be  necessary  to  the
         performance of this Agreement for a Party (the "Disclosing Party")
         to  disclose to the other Party (the  "Receiving  Party")  certain
         information   that  each  Party  deems  to  be  confidential   and
         proprietary.  The Receiving  Party shall maintain the security and
         confidentiality of all Confidential  Information received from the
         Disclosing Party hereunder.

12.2     For purposes  hereof,  "Confidential  Information"  shall  include
         business  and  technical  information  or  data  relating  to  the
         Disclosing  Party  and  its  representatives  that is  reduced  to
         writing  and  marked   "Confidential"  by  the  Disclosing  party.
         Notwithstanding   anything   contained  herein  to  the  contrary,
         Confidential   Information   shall  not  include  (i)  information
         developed   independently  by  the  Receiving  Party  or  lawfully
         received   from  a  third  party  not  under  an   obligation   of
         confidentiality;  or (ii)  information  in the public  domain;  or
         (iii)  information known by Receiving Party prior to the execution
         of this Agreement;  or information disclosed pursuant to law; (iv)
         judicial order or governmental regulation.
<PAGE>
 
12.3     The  Receiving  Party shall not use nor  communicate,  directly or
         indirectly, any of the Confidential Information to any third party
         without the prior written  consent of the  Disclosing  Party.  The
         Receiving Party shall use its best efforts to prevent  inadvertent
         disclosure of all or any part of the  Confidential  Information to
         any third party.

12.4     The  Receiving  Party's   obligations  under  this  Article  shall
         continue  for a period of two (2) years after the  termination  or
         expiration  of  this  Agreement  with  respect  to  each  item  of
         Confidential Information disclosed hereunder. Upon such expiration
         or  termination,  the Receiving  Party shall return or destroy all
         Confidential Information of the other Party in its possession.

13.      INTELLECTUAL PROPERTY  RIGHTS

         The   Parties   agree  that   trademarks,   inventions,   patents,
         copyrights, registered designs, service marks, trade names and all
         other  intellectual  property shall remain in the ownership of the
         person or party  originating  the same and  nothing  herein  shall
         confer or be deemed to confer on either Party  expressly,  implied
         or otherwise,  any rights or licenses in the intellectual property
         of the other.

14.      AMENDMENT

         This Agreement together with all Attachments and Exhibits,  may be
         amended, modified or amplified only by written agreement signed by
         authorized representatives of both Parties.

15.      WAIVER OF TERMS

         No waiver by either Party of any provision of this Agreement shall
         be binding unless  expressly  confirmed in writing.  Further,  any
         such  waiver  shall  relate  only  to  such   particular   matter,
         non-compliance  or breach as it expressly relates to and shall not
         apply to any subsequent or other matter, non-compliance or breach.

16.      GOVERNING LAW AND FORUM

16.1     The  existence,  validity,  construction,  operation and effect of
         this  Agreement  shall be  determined  in  accordance  with and be
         governed by the laws of the State of New York.

16.2     Any  dispute  arising out of or related to this  Agreement,  which
         cannot  be  resolved  by  negotiation   within  thirty  (30)  days
         following the date on which  written  notice of a dispute has been
         given to the other Party, shall be settled by binding  arbitration
         in accordance with the  J.A.M.S./ENDISPUTE  Arbitration  Rules and
         Procedures,  as amended by this  Agreement.  The number of neutral
         arbitrators  shall be three (3), one appointed by each Party,  and
         the third  appointed  by the other two  arbitrators.  The place of
         arbitration  shall be Washington,  D.C. The costs or  arbitration,
         including  the  fees and  expenses  of the  arbitrators,  shall be
         shared  equally  by  the  parties  unless  the  arbitration  award
         provides  otherwise.  Each party shall bear the cost of  preparing
         and presenting its case. The parties agree that this provision and
         the arbitrator's authority to grant relief shall be subject to the
         United States  Arbitration Act, 9 U.S.C. 1-16 et seq. ("USAA") and
         the provisions of this  Agreement.  The  arbitrators  shall comply
         with the  ABA-AAA  Code of Ethics for  Arbitrators  in  Commercial
         Disputes.  The parties  agree that the  arbitrators  shall have no
         power or  authority  to make  awards  or issue  orders of any kind
         except as expressly  permitted by this Agreement,  and in no event
         shall the  arbitrators  have the  authority to make any award that
         provides  for  punitive or  exemplary  damages.  The  arbitrators'
         decision  shall be final and  binding.  The award may be confirmed
         and  enforced  in  any  court  of  competent   jurisdiction.   All
         post-award proceedings shall be government by the USAA.
<PAGE>
 
17.      NOTICES

17.1     All notices,  invoices  and other  communications  made  hereunder
         shall be given in  writing  and  shall be deemed to have been duly
         given and effective (i) upon receipt, if delivered in person or by
         telecopy,  with  confirmation;  or (ii) one (1) day after  deposit
         prepaid  with  a  U.S.  domestic  overnight  express  service  for
         domestic  delivery;  or (iii) three (3) days after  deposit in the
         United States mail,  certified,  postage  prepaid,  return receipt
         requested;  or (iv) five (5) days after  deposit with an overnight
         express service for international delivery service.

         Notices to COMSAT of a contractual nature shall be directed to the
         following address:

         COMSAT Mobile Communications
         6560 Rock Spring Drive
         Bethesda, Maryland 20817
         Attention:  Contracts Department
         Telephone Number:  (301) 214-3450
         Facsimile Number:  (301) 214-7113

         Notices to COMSAT  related to invoices  and  collections  shall be
         directed to the following addresses:

         COMSAT Mobile Communications
         6560 Rock Spring Drive
         Bethesda, Maryland  20817
         Attention: Revenue Accounting Department
         Telephone Number:  (301) 214-3000
         Facsimile Number:  (301) 214-7113

         Notices to MCI of a  contractual  nature  shall be directed to the
         following address:

         MCI International, Inc.           MCI Worldcom, Inc.
         2 International Drive             1717 Pennsylvania Avenue, N.W.
         Rye Brook, New York  10573        Washington, D.C.  20006
         Attention:                        Attention: International Commercial 
                                              Affairs Law and Public Policy
         Telephone Number:                            
         Facsimile Number:                 Facsimile Number:  (202) 721-2549

         Notices  to MCI  related  to  invoices  and  collections  shall be
         directed to the following address:

         MCI International, Inc.
         2 International Drive
         Rye Brook, New York  10573
         Attention:
         Telephone Number:
         Facsimile Number:

18.      MISCELLANEOUS

18.1     No Third Party  Beneficiary.  The provisions of this Agreement are
         for the benefit only of the Parties hereto, and no third party may
         seek to enforce or benefit from those provisions.

18.2     No Partnership Or Agency  Relationship.  The relationship  between
         COMSAT  and MCI  shall  not be that of  partners  or agents of one
         another,  and nothing  contained in this Agreement shall be deemed
         to constitute a partnership or agency agreement between them.
<PAGE>
 
18.3     Successors and Assigns.  This Agreement shall be binding upon and 
         inure to the benefit of each Party's successors and permitted 
         assignees.

18.4     Headings.  The titles in the headings of  paragraphs  are intended
         for  organization  and  convenience  only and do not  apply in the
         interpretation of any of the Agreement terms.

18.5     Survival  of Terms.  The terms and  provisions  contained  in this
         Agreement  that by their sense and context are intended to survive
         the performance thereof by the Parties hereto shall so survive the
         completion of

18.6     Rule  of   Construction.   No  rule  of   construction   requiring
         interpretation  against the  drafting  party hereof shall apply in
         the interpretation of this Agreement.

19.      ENTIRE AGREEMENT

         This Agreement,  together with all attachments incorporated herein
         specifically by reference,  represents the entire understanding of
         the  Parties  with  respect to the subject  matter  hereof and all
         other agreements (written or oral) between the Parties relating to
         the Service shall be superseded by this Agreement.

20.      SEVERABILITY

         If any one or more of the  provisions  contained in this Agreement
         or any document executed in connection  herewith shall be invalid,
         illegal or  unenforceable in any respect under any applicable law,
         the  validity,   legality  and  enforceability  of  the  remaining
         provisions  contained  herein  shall not in any way be affected or
         impaired;  provided,  however, that in such case the Parties agree
         to use their best  efforts to achieve  the  purpose of the invalid
         provision by a new legally valid stipulation.

 21.     SUPERSEDES OTHER AGREEMENTS

         This Agreement  specifically  supersedes and cancels the Agreement
         dated  1  September   1993,   entered   into  by  COMSAT  and  MCI
         International,  Inc.,  which  Agreement  shall be null  and  void,
         except for any  liabilities  of the Parties that arise  thereunder
         prior  to  the  date  of  such   cancellation   and  which  remain
         outstanding.


IN WITNESS  WHEREOF,  the Parties  hereto have executed  this  Agreement in
counterparts on the day and year first above written.

COMSAT Mobile Communications,                  MCI International, Inc.
a business unit of COMSAT Corporation

/s/ Carol M. Schoonhoven                       /s/ Anthony Cirieco
CAROL M. SCHOONHOVEN                           ANTHONY CIRIECO
20 NOVEMBER 1998                               11/6/98

<PAGE>
 
                                                                  EXHIBIT 10.32





                            INTERCONNECTION AND
                             SERVICES AGREEMENT



                                  between




                           AT&T Maritime Services



                                    and



                        COMSAT Mobile Communications








                                June 1, 1996
<PAGE>
 
                             TABLE OF CONTENTS



1.       Interconnection of Facilities........................................2
2.       Circuit Restoration and Rerouting....................................2
3.       Service Offerings................................................... 3
4.       Service Modification.................................................4
5.       Traffic Volumes and Rates............................................4
6.       Accounting and Settlement Procedures.................................5
7.       Failure to Pay.......................................................7
8.       Technical Standards and Methods of Operation.........................7
9.       Exchange of Proprietary Information..................................7
10.      Governmental Approvals...............................................8
11.      Prior Agreements.....................................................9
12.      Notices..............................................................9
13.      Duration and Termination of Agreement................................9
14.      Change in Circumstances..............................................9
15.      Limitation of Liability.............................................10
16.      Assignment..........................................................10
17.      Governing Law.......................................................10
18.      Severability........................................................10
19.      Waiver..............................................................11
20.      Execution and Amendment.............................................11
<PAGE>
 
                   INTERCONNECTION AND SERVICES AGREEMENT


         THIS  AGREEMENT,  entered  into this 1st day of June 1996,  by and
between COMSAT Corporation,  acting through its business unit COMSAT Mobile
Communications,  a corporation organized and existing under the laws of the
District of  Columbia,  with  offices  located at 6560 Rock  Spring  Drive,
Bethesda,  Maryland  20817  (hereinafter  referred  to as  "COMSAT,"  which
expression  shall include its successors and permitted  assignees) and AT&T
Corp., acting through its business unit AT&T Mobile Satellite  Services,  a
corporation organized and existing under the laws of the State of New York,
with  offices  located at 101 JFK Parkway,  Short  Hills,  New Jersey 07078
(hereinafter  called "AT&T," which  expression shall include its successors
and permitted assignees).


                            W I T N E S S E T H:


         WHEREAS,  COMSAT and AT&T are both communications  common carriers
subject  to the  jurisdiction  of  the  Federal  Communications  Commission
("FCC"); and

         WHEREAS, COMSAT offers mobile satellite communications services to
and  from  mobile   stations  and  COMSAT's  Land  Earth  Station   ("LES")
facilities,  with associated  Mobile  Satellite  Switching  Center ("MSSC")
facilities, using satellite capacity obtained from the International Mobile
Satellite Organization ("Inmarsat"); and

         WHEREAS,  AT&T  provides  telecommunications  services to and from
customers    in   the   United    States   and    operates    international
telecommunications  channels  jointly with various foreign  administrations
and  carriers   (hereinafter   "international   correspondents")   for  the
furnishing of its authorized  services  between points in or served via the
United  States and other  points  outside  the United  States  (hereinafter
referred to as "international" or "overseas" points); and

         WHEREAS,  COMSAT  and AT&T have  previously  interconnected  their
facilities  and  exchanged  traffic  so  as  to  permit  the  provision  of
telecommunications  services  between mobile earth stations located outside
the  United  States and points in the  United  States  served by AT&T,  and
international points served by AT&T with its correspondents; and

         WHEREAS,  it is the  desire of AT&T and COMSAT to enter into a new
inter-carrier  agreement,  and to establish  terms and  conditions  for the
exchange of traffic as each may choose to deliver to the  facilities of the
other;

         NOW, THEREFORE, in consideration of the mutual covenants contained
herein, COMSAT and AT&T agree as follows:
<PAGE>
 
1.       Interconnection of Facilities

         a.  COMSAT and AT&T agree to  continue  to  interconnect  COMSAT's
LES/MSSC facilities and AT&T's switched network facilities to provide voice
and data  telecommunications  services  between  the  geographic  and ocean
regions  covered by the Inmarsat  system served by COMSAT and points in the
United States and international points served by AT&T.

         b.  The  interconnecting  circuits  to be  used in  providing  the
services  set  forth  in this  Agreement  shall  be such  circuits  between
COMSAT's MSSC facilities and AT&T's  International  Switching Centers ("ISC
facilities")  as may presently  exist and such  additional  or  replacement
circuits as the parties may from time to time agree upon.

         c. Each party shall be responsible for providing and  maintaining,
at its own expense and liability,  the circuits  located on its side of the
interconnecting  circuits.  COMSAT shall  reimburse AT&T for half of AT&T's
direct cost of terrestrial  circuits  connecting  AT&T's ISC facilities and
COMSAT's  MSSC  facilities.  The  number  of  circuits  necessary  for  the
provision  of  services  hereunder  shall be  mutually  agreed  between the
parties,  based on the  amount  of  traffic  to be  exchanged  between  the
parties.

         d.  COMSAT and AT&T agree that this  Agreement  is not  exclusive.
Accordingly,  each party  shall have the right to  interconnect  with other
telecommunications  and  satellite  service  providers to exchange  traffic
including,  but not limited to, the services  set forth in this  Agreement,
consistent with applicable laws.

2.       Circuit Restoration and Rerouting

         a. Each party  shall  advise the other party in writing as soon as
practicable, and in any event no later than twenty-four (24) hours after it
becomes  aware of the  occurrence,  of any facility  failure in its network
that is causing  any  significant  impairment  or  interruption  of service
provided under this Agreement, and the party experiencing the failure shall
make all reasonable efforts to implement prompt restoration of service.

         b. COMSAT shall make  arrangements,  as commercially  practicable,
with foreign  telephone  administrations  for rerouting and  restoration of
service  in the  event of  disruption  of mobile  satellite  communications
service through COMSAT's LES facilities,  and in such cases shall make such
alternative facilities available to route AT&T mobile satellite traffic.

         c. For maintenance and operational purposes,  both AT&T and COMSAT
agree that the mobile satellite telephony services provided hereunder shall
be  treated  with no less  diligence  than  either  party  treats its other
telephony services.
<PAGE>
 
3.       Service Offerings

         a.       Voice Message Telecommunications Services

                  AT&T and COMSAT hereby agree to make the following  voice
message  telecommunications  services  available to end users to the extent
practicable:

                 (i)      Directory Assistance.  COMSAT will make available 
mobile directory assistance, including but not limited to mobile station 
listings.  AT&T will make available directory assistance for U.S. shore points.

                 (ii)     Conference Calling Capabilities.

                 (iii)    Mobile Terminal to Mobile Terminal Calling.

                 (iv)     Person/Station Calling.  Both person-to-person and 
station-to-station  calls  will be  permitted  by  COMSAT  and AT&T for 
maritime and international land mobile satellite service. Only station-to-
station calls will be provided by COMSAT and AT&T for  aeronautical  satellite  
telephone service.

                 (v)      Calling Card Calls.  To the extent AT&T is able to 
bill COMSAT's  mobile-to-fixed  tariffed  rates,  COMSAT shall have the right 
to accept AT&T's Calling Cards on calls from mobile stations  outside the U.S.
to the  U.S.  and  international  points  as  long as the  Calling  Card is
validated (i.e., a positive or indeterminate  response is received from the
validator  system).  To the  extent  changes  to  COMSAT's  tariff  require
modifications  to AT&T billing  systems or billing rates in connection with
Calling  Card  calls,  AT&T shall use its  reasonable  efforts to make such
modifications.  AT&T  shall  notify  COMSAT  promptly  and in writing as to
whether  such  modifications  can be  made  by  AT&T.  Notwithstanding  the
foregoing,  COMSAT  shall not route any  mobile-to-fixed  800 calls to AT&T
until AT&T notifies COMSAT otherwise,  and until such time COMSAT shall not
bill AT&T in connection with any such calls.

                  (vi)     Collect Calls.  Except for collect calls to coin 
telephones, collect calls  shall be  permitted  by COMSAT and AT&T in both  
directions  between mobile  stations and fixed  locations  within the United 
States,  excluding Alaska.

                  (vii)    Distress and Safety.  Messages and replies
in connection with situations  involving  maritime and aeronautical  safety 
will be handled in compliance with national and international regulations.

         b.       Data, Facsimile and Other Digital Network Services

                  Transmission   of  data,   facsimile  and  other  digital
services will be permitted  over the network  facilities of AT&T and COMSAT
to the extent practicable.
<PAGE>
 
4.       Service Modification

         The  services  listed in Article 3 above may be modified and other
services added by written agreement of the parties. Each party reserves the
right  (subject to any FCC  requirements)  to  discontinue  any  individual
customer service set forth in Article 3 upon ninety (90) days prior written
notice to the other party.  The decision by either party to discontinue any
individual service shall not constitute a termination of any other service,
nor can the procedure  established by this Article for  individual  service
modification  be utilized to terminate this Agreement  substantially  or in
its entirety.

5.       Traffic Volumes and Rates

         a. AT&T will pay  COMSAT  $6.50 per minute for the space and earth
station  segments  of  fixed-to-mobile   traffic  to  Inmarsat  Standard  A
terminals  for traffic up to one million  minutes per year.  For Inmarsat A
traffic  volumes  exceeding  that  amount,  COMSAT  agrees  to  reduce  the
foregoing   rate  in  accordance   with   Attachment  I  hereto.   For  all
fixed-to-mobile  traffic to Standard M and Standard B terminals,  AT&T will
pay COMSAT $3.30 per minute for calls  destined to the Atlantic and Pacific
Ocean regions,  and $2.95 per minute for calls destined to the Indian Ocean
Region.

         b.  COMSAT  will pay AT&T $.20 per minute for all  mobile-to-fixed
calls   terminating   in  the   United   States   and  for   all   Inmarsat
mobile-to-mobile  calls routed via AT&T for the terrestrial segment of that
traffic and associated  services.  For  mobile-to-fixed  calls  terminating
outside the United States,  COMSAT will pay AT&T's  tariffed  international
long distance rates minus ten percent (10%).

         c.  Inmarsat aeronautical calls shall be settled as follows:

             (i)  For air-to-ground calls, COMSAT shall pay AT&T $.20 per 
minute.

             (ii) For ground-to-air calls, AT&T shall pay COMSAT $6.50
per minute.

         d.  Notwithstanding  anything to the  contrary in this  Agreement,
except in  regards  to the  proportion  of  traffic  described  in  Article
6.a.(6),  neither  AT&T nor  COMSAT  commits  to send the  other  party any
traffic,  nor does either party commit to any particular  volume or type of
traffic,  by reason of this  Agreement.  Each party  reserves  the absolute
right to adjust  or change  the  volume  of  traffic  it sends to the other
party. In this connection,  and without  limitation,  COMSAT and AT&T agree
that there will be no shortfall obligation, charge or penalty for a party's
failure to deliver any traffic volumes,  even if the reason for such action
is within the control of such party.
<PAGE>
 
         e. Any tariff changes  affecting  services provided in conjunction
with this  Agreement  shall be provided by written notice in the manner set
forth in Article 12 by the party  making the  changes to the other party on
or before the date the tariff  changes are submitted to the FCC,  provided,
in any event,  that COMSAT shall notify AT&T of Calling Card tariff changes
no less than fifteen (15) days before the tariff is to become effective.

6.       Accounting and Settlement Procedures

         a.       Monthly Statements

                  (1)      Each party shall be responsible  for the billing
                           and  collection  of  charges  to its  respective
                           customers.

                  (2)      Each party  shall  render to the other a monthly
                           statement  of the messages  provided  during the
                           month to which the statement relates,  expressed
                           in seconds,  but with totals rounded to the next
                           full  minute and showing the portion of revenues
                           due to the other party  calculated  on the basis
                           of the rates set forth in  Article  5. Each line
                           item total  shall be rounded up to the next full
                           minute.  Such  statements  shall be forwarded to
                           the other party as soon as practicable after the
                           calendar  month to which the statement  relates,
                           but in no event later than the end of the second
                           calendar month  following the month to which the
                           statement relates.  The monthly statements shall
                           include  any  accounting   information  received
                           through international settlements.  This traffic
                           will be  reported  and  included  in the monthly
                           statements no later than one (1) month following
                           the  date  it is  reported  to the  party.  Both
                           parties  acknowledge that international  traffic
                           may be reported over time (in some  instances in
                           excess  of  one  (1)  year  after   service  was
                           provided).

                  (3)      Each party  shall have the right to make  credit
                           adjustments  to its  customers  with  respect to
                           periods in which  transmission is interrupted or
                           defective,   and  to  reflect,  in  its  monthly
                           statements  to the other party,  deductions  for
                           such  interrupted  or  defective  transmissions,
                           provided that such deductions or adjustments are
                           reasonable  and  are  made  before  the  monthly
                           statement  is  forwarded  to  the  other  party.
                           COMSAT  shall  validate  all AT&T  Calling  Card
                           calls. Without prejudice to the foregoing and in
                           addition to any other  remedies AT&T may have at
                           law or in equity, AT&T specifically reserves the
                           right to block calls  billed to any  unvalidated
                           AT&T  Calling  Card or deduct  the value of such
                           calls from its settlement  payments to COMSAT in
                           the event of nonpayment for the unvalidated call.


                  (4)      A  statement   shall  be  deemed  to  have  been
                           irrevocably  accepted  as free of  discrepancies
                           and  errors by the party to whom it is  rendered
                           if that party
<PAGE>
 
                           does not object in writing  within one year from
                           the date the monthly  statement is received.  If
                           an  objection  is made,  the  parties  shall use
                           their  best  efforts  to  settle   promptly  the
                           disputed  item or items.  Adjustments  that have
                           been  agreed  upon  by  both  parties  shall  be
                           included in the next monthly statement.

                  (5)      The parties agree to exchange  billing data only
                           to  the  extent  it  is  strictly  necessary  to
                           respond to a  specific  customer  inquiry.  This
                           exchange  shall be made in a timely  manner (per
                           recommendations  of the International  Telegraph
                           and Telephone Consultation Committee ("CCITT")),
                           in a format to which both parties agree,  and in
                           accordance    with    all    applicable    legal
                           requirements.

                  (6)      Where    COMSAT   and   a   foreign    telephone
                           administration  have  entered  into an agreement
                           providing  for that  telephone  administration's
                           routing of traffic  originating in its territory
                           and    terminating    via   COMSAT's    Inmarsat
                           facilities, and AT&T provides connecting service
                           to  that  administration  with  respect  to such
                           traffic,  AT&T hereby  agrees to route to COMSAT
                           such  traffic  equal to the share of all traffic
                           such telephone  administration  has agreed to so
                           route to COMSAT.  Where AT&T provides connecting
                           service  with  respect  to  such  traffic,  AT&T
                           agrees  to  accept  payment  from  such  foreign
                           telephone administrations through the settlement
                           process  on behalf of  COMSAT,  but shall not be
                           required to bill, collect from, or determine the
                           method of  payment of end users and shall not be
                           responsible  for late or  non-payment  from such
                           telephone administrations. Any payments received
                           by AT&T from such  administrations  on  COMSAT's
                           behalf shall be paid in accordance  with Article
                           6.b. below.

          b.      Payment of Net Balance

                  The sums due each  month  from each party to the other as
covered by each monthly statement shall be reduced to a net balance by each
party.  Net  balances due from one party to the other shall be paid monthly
by the debtor party to the creditor party.  Payment will be made as soon as
practicable,  but in no event  later  than  forty-five  (45) days after the
monthly statement has been received from the creditor party. The payment of
the net  balance due with  respect to  undisputed  amounts on a  statement,
except to the extent that such amounts are uncollected  settlement payments
from a  foreign  telephone  administration,  shall not be  delayed  pending
agreement to the adjustment of disputed items of that statement.
<PAGE>
 
           c.     Other Matters

                  Payments  made  and   statements   rendered   under  this
Agreement  from one  party to the  other  shall be in U.S.  currency.  AT&T
hereby  commits  to work  with  COMSAT on a  regular  basis to  review  and
streamline the  accounting  and settlement  process in an effort to improve
the timeliness of payments.


  7.      Failure to Pay

          Subject to the terms of Article  6.a.  and  Article  6.b. of this
  Agreement,  upon  failure of a party to pay a net  balance in  accordance
  with Article  6.b.,  the party to whom such  balance is owed may,  ninety
  (90) days after  delivering  notice in writing  to the other  party,  and
  subject to FCC  requirements,  suspend its  participation in the services
  covered  hereby,  and  said  party  shall  be  deemed  released  from its
  obligations  under this  Agreement  for so long as any  balance due shall
  remain unpaid. This provision does not limit any other legal or equitable
  remedies available under this Agreement.

  8.      Technical Standards and Methods of Operation

          Except  as  otherwise  agreed  by  the  parties,   the  technical
  standards and methods of operation applied by the parties to the exchange
  of traffic hereunder shall conform to the applicable  recommendations  of
  the CCITT and to any revisions of same.

  9.      Exchange of Proprietary Information

          a. In connection with the provision of services  pursuant to this
  Agreement,  COMSAT  and AT&T  may  each  disclose  to the  other  certain
  marketing,  financial, billing, technical, and other information which is
  proprietary or  confidential  to the  disclosing  party or its affiliated
  companies  (hereinafter  referred to as  "Information").  For purposes of
  this Agreement,  such Information  shall include,  but not be limited to,
  engineering information,  hardware,  software, drawings, models, samples,
  tools,  technical  specifications,  and  documentation,  in whatever form
  recorded or orally provided.

          b. The  receiving  party shall hold  Information  in  confidence,
  shall  use such  Information  only for the  purpose  of  performing  this
  Agreement,  shall reproduce such Information only to the extent necessary
  for such purpose,  shall restrict  disclosure of such  Information to its
  employees and employees of its  affiliated  companies with a need to know
  (and inform such employees of the obligations assumed herein),  and shall
  not disclose  such  Information  to any third party without prior written
  approval of the other party. These restrictions on the use or disclosure
  of information shall not apply to any Information:
<PAGE>
 
                   (i) that is  independently  developed  by the  receiving
                   party or its affiliated  companies or lawfully  received
                   free of restriction from another source having the right
                   to so furnish such Information;

                   (ii) that has become  generally  available to the public
                   without breach of this Agreement by the receiving  party
                   or its affiliated companies;

                   (iii) that at the time of  disclosure  to the  receiving
                   party  was  known  to  such  party  or  its   affiliated
                   companies   free  of   restriction   and   evidenced  by
                   documentation in such party's possession;

                   (iv) that the disclosing party agrees in writing is free
                   of such restrictions; or

                   (v) that is  required  to be made  public  by the FCC or
                   other due legal process,  provided the disclosing  party
                   is notified  promptly by the receiving party of any such
                   requirement to make the Information public.

          c. Information shall be subject to the restrictions  above, if it
  is in  writing  or  other  tangible  form,  only  if  clearly  marked  as
  proprietary or confidential  when disclosed to the receiving party or, if
  it is  not in  tangible  form,  only  if  identified  as  proprietary  or
  confidential  at the time of disclosure  and confirmed in writing  within
  thirty (30) days of such disclosure.

          d. No license to a party, under any trademark, patent, copyright,
  mask work protection right or any other  intellectual  property right, is
  either  granted or implied by the conveying of Information to such party.
  None of the  Information  which  may be  disclosed  or  exchanged  by the
  parties  shall  constitute  any  representation,   warranty,   assurance,
  guarantee or inducement by either party to the other of any kind, and, in
  particular, with respect to the non- infringement of trademarks, patents,
  copyrights,  mask  work  protection  rights  or  any  other  intellectual
  property rights, or other rights of third persons.

          e. All Information  shall remain the property of the transmitting
  party and shall be returned  upon written  request or upon the  receiving
  party's determination that it no longer has a need for such Information.

          f. Each party agrees that all of its  obligations  undertaken  in
  Article 9 herein  as a party  receiving  Information  shall  survive  and
  continue after termination of this Agreement.
<PAGE>
 
  10.     Governmental Approvals

          All  undertakings,  obligations  and rights of the parties hereto
  are subject to all necessary governmental licenses and approvals,  and to
  all other  applicable  legal  requirements.  This Agreement  shall not be
  construed or interpreted to prejudice the rights either party may have to
  provide any services it is or becomes lawfully  authorized to provide, or
  in any way limit the ability of each party to present any  regulatory  or
  other legal position, or to request or oppose any grant of authority,  in
  any appropriate legal forum.

  11.     Prior Agreements

          This Agreement supersedes all previous agreements  (including all
  amendments  thereto)  between  COMSAT and AT&T regarding the provision of
  mobile satellite telephone services using the Inmarsat system.

  12.     Notices

          Any notice under this Agreement  shall be in writing and shall be
  deemed sufficient if sent by first class mail,  facsimile or telex to the
  following address, or any superseding address so notified hereunder,  and
  shall be effective upon receipt.

  To COMSAT:

          COMSAT Mobile Communications
          6560 Rock Spring Drive
          Bethesda, Maryland 20817
          Attention: Director-Contracts

  To AT&T:

          AT&T Corp.
          101 JFK Parkway
          Short Hills, New Jersey  07078
          Attention: District Manager Maritime Services

  13.     Duration and Termination of Agreement

          This  Agreement will be effective as of June 1, 1996, and subject
  to the  provisions  contained  herein,  shall  continue in full force and
  effect until  December  31, 1997.  Subsequent  to the initial  term,  the
  Agreement  shall  continue in full force and effect unless  terminated by
  either party upon ninety (90) days prior notice in writing.

  14.     Change in Circumstances

          If,  during  the term of this  Agreement,  any U.S.  governmental
  action or other significant change in circumstances  renders either party
  unable to  perform  or  results  in  significant  economic  detriment  or
  competitive  disadvantage  to a party,  such party may request in writing
  that the terms of this Agreement be renegotiated.  Upon such request, the
  parties  agree to  negotiate,  promptly  and in good  faith,  methods  to
  resolve the competitive disadvantage,  economic detriment or inability to
  perform.  However,  if no such mutual  agreement can be reached  within a
  period of ninety (90) days with respect to a party's inability to perform
  under this Agreement,  either party may terminate this Agreement  without
  further cost or liability,  except for any unpaid amounts owed by a party
  hereunder at the time of such termination.
<PAGE>
 
  15.     Limitation of Liability

          Neither party nor its parent,  subsidiaries,  or affiliates shall
  be  liable  to  the  other  for  any  failure  in  or  breakdown  of  the
  communications  facilities or  interruption  to same  associated with the
  functioning  of the services  set forth in this  Agreement no matter what
  the cause. Each party's liability to the other for any loss, cost, claim,
  injury,  liability,  or expense,  including  reasonable  attorneys' fees,
  relating  to or  arising  out of any  negligent  act or  omission  in its
  performance  of  this   Agreement  (not  involving   knowing  or  willful
  misconduct  or a failure,  breakdown  or  interruption  of  communication
  facilities or services provided hereunder) shall be limited to the amount
  of direct damage actually incurred. NEITHER PARTY SHALL BE LIABLE FOR ANY
  INDIRECT,   SPECIAL,  PUNITIVE  OR  CONSEQUENTIAL  DAMAGES  OF  ANY  KIND
  WHATSOEVER,  INCLUDING  LOSS OF PROFITS OR REVENUES.  EXCEPT AS EXPRESSLY
  SET FORTH HEREIN,  NEITHER PARTY MAKES ANY WARRANTIES OR REPRESENTATIONS,
  EXPRESS OR IMPLIED.

  16.     Assignment

          Neither  party may assign  this  Agreement  except to a parent or
  wholly-owned subsidiary in connection with the transfer of responsibility
  for the services  provided under this Agreement without the prior written
  consent of the other, which consent shall not be unreasonably withheld or
  delayed.

  17.     Governing Law

          This  Agreement  shall be  governed  by the laws of the  State of
  Maryland, United States of America, without regard to the conflict of law
  principles  thereof.   This  Agreement  shall  also  be  subject  to  all
  applicable laws of the United States,  including  without  limitation the
  Communications Act of 1934, as amended and U.S. Export Control laws.

  18.     Severability

          If any term or provision of this  Agreement  shall be found to be
  illegal or  unenforceable,  then such term or  provision  shall be deemed
  stricken,  and the  remainder of this  Agreement  shall  continue in full
  force and effect.
<PAGE>
 
  19.     Waiver

          No term or provision of this Agreement  shall be deemed waived by
  either party unless such waiver is in writing and signed by that party.

  20.     Execution and Amendment

          This Agreement is executed in two copies,  both of which shall be
  considered  originals with identical legal effect.  This Agreement may be
  modified or amended only by written agreement of the Parties.

          IN WITNESS WHEREOF,  the parties hereto have severally subscribed
  these presents or caused them to be subscribed,  in their name and behalf
  by their respective officers thereunto duly authorized.


  AT&T Maritime Services AT&T CORP.

  By:            /s/ Mario Persico
  Name:          Mario Persico
  Title:         District Manager
  Date:          June 25, 1996


  COMSAT Mobile Communications
  COMSAT Corporation

  By:            /s/ Thomas Collins
  Name:          Thomas Collins
  Title:         VP  & GM, CMC
  Date:          6/20/96

<PAGE>
 
                                                                  EXHIBIT 10.50






                           MASTER LEASE AGREEMENT

                               BY AND BETWEEN

                    LCOR CLARKSBURG L.L.C., AS LANDLORD

                                    AND

                       COMSAT CORPORATION, AS TENANT





                  CLARKSBURG, MONTGOMERY COUNTY, MARYLAND







Version 10
<PAGE>
 
                             TABLE OF CONTENTS




INTRODUCTION
Section 1.  DEFINITIONS......................................................1
Section 2.  LEASE OF MASTER LEASE PROPERTY...................................2
Section 3.  TERM.............................................................2
Section 4.  RENT.............................................................4
Section 5.  USE OF THE MASTER LEASE PROPERTY.................................7
Section 6.  DEVELOPMENT; DESIGNATION OF THE EXCLUDED AREAS...................9
Section 7.  TAXES AND IMPOSITIONS...........................................11
Section 8.  UTILITIES.......................................................15
Section 9.  SIGNS...........................................................15
Section 10. AS-IS CONDITION OF MASTER LEASE PROPERTY........................16
Section 11. REPAIRS, MAINTENANCE AND MANAGEMENT.............................16
Section 12. ACCESS TO MASTER LEASE PROPERTY.................................18
Section 13. ALTERATIONS AND PERSONAL PROPERTY...............................19
Section 14. INSURANCE.......................................................22
Section 15. DAMAGE OR DESTRUCTION...........................................25
Section 16. INDEMNIFICATION.................................................31
Section 17. CONDEMNATION....................................................35
Section 18. LIENS...........................................................36
Section 19. EXISTING SPACE LEASES; ASSIGNMENT AND SUBLETTING................37
Section 20. SUBORDINATION OR SUPERIORITY OF LEASE...........................40
Section 21. DEFAULTS AND REMEDIES...........................................40
Section 22. BANKRUPTCY OR INSOLVENCY........................................45
Section 23. SURRENDER OF MASTER LEASE PROPERTY..............................47
Section 24. NON-CONSENSUAL HOLDING OVER.....................................48
Section 25. QUIET ENJOYMENT.................................................48
Section 26. NOTICES.........................................................48
Section 27. HAZARDOUS MATERIALS.............................................49
Section 28. RIGHT TO RENEW TERM.............................................52
Section 29. SECURITY DEPOSIT................................................54
Section 30. MISCELLANEOUS GENERAL PROVISIONS................................54

SCHEDULE I  Defined Terms
SCHEDULE II Deductibles
SCHEDULE OF EXHIBITS

Version 10
<PAGE>
 
                           MASTER LEASE AGREEMENT


                  THIS LEASE  AGREEMENT  (this "Lease") is entered into and
made  effective  as of the  12th day of  September,  1997  (the  "Effective
Date"), by and between LCOR CLARKSBURG L.L.C., a Delaware limited liability
company  ("Landlord")  and  COMSAT  Corporation,  a  District  of  Columbia
corporation ("Tenant").

                                WITNESSETH:

                  (a) Prior to but contemporaneously with the execution and
delivery  of this  Lease,  Tenant  sold and  transferred  the Master  Lease
Property to Landlord  pursuant to that certain  Agreement of Sale dated the
Effective  Date,  by and  between  Tenant,  as  seller,  and  Landlord,  as
purchaser (the "Purchase and Sale Agreement").

                  (b)  Landlord  desires  to lease to  Tenant,  and  Tenant
desires to lease back from Landlord,  the Master Lease Property, all as set
forth and on the terms and conditions contained in this Lease.

                  NOW THEREFORE,  in  consideration  of the mutual promises
set forth in this  Lease and other  good and  valuable  consideration,  the
receipt and sufficiency of which are  acknowledged by each party,  Landlord
and Tenant agree as follows:

                  SECTION 1.        DEFINITIONS

                  (a) The following terms shall have the meanings  ascribed
thereto below:

                  Agents:  The agents, employees, contractors,
subcontractors, affiliates, licensees and invitees of each party
(and in the case of Tenant, subtenants).

                  Excluded Areas:  Any areas of the Master Lease Property
excluded by Landlord pursuant to Section 6.

                  Expiration Date:  The ending date of the Term.

                  Installations  Premises:  Certain portions of the Land as
described  or shown on  Exhibit C attached  hereto and made a part  hereof,
together with all improvements located thereon.

                  Land:   Approximately   227  acres  of  land  located  in
Clarksburg, Montgomery County, Maryland, as described or shown on Exhibit A
attached hereto and made a part hereof.

                  Main  Building:  A building  complex  consisting of three
buildings  (the  "Component  Buildings")  which,  for the  purposes of this
Lease,  Landlord and Tenant agree contain, in the aggregate,  496,000 gross
square feet of space (the "Main Building  Space"),  located on the Land and
commonly known as 22250, 22300, and 22240

Version 10
<PAGE>
 
COMSAT  Drive,  Clarksburg,  Maryland.  Further,  for the  purposes of this
Lease,   Landlord  and  Tenant  agree  that  the  Component  Buildings  are
designated as, and contain amounts of Main Building Space, as follows:

                  Building A:  The largest of the Component Buildings,
                  commonly known as the primary building; 446,000 gross
                  square feet;

                  Building B:  The second largest of the Component
                  Buildings, commonly known as the Spectra building;
                  40,000 gross square feet;

                  Building  C: The  smallest  of the  Component  Buildings,
                  commonly  known  as the  etching  and  plating  building;
                  10,000 gross square feet.

                  Main  Building  Area:  The Main  Building and the Parking
Areas,  access  drives,  and  other  appurtenant  areas  serving  the  Main
Building,  as  described  or shown on Exhibit B attached  hereto and made a
part hereof.

                  Master Lease Property:  The Land, together with all
improvements located thereon, less the Installations Premises and
the Excluded Areas.  The Master Lease Property includes, without
limitation, the Main Building Area.

                  Parking Areas:  Those certain areas located in the Main
Building Area and designated for use for parking of motor
vehicles as of the Effective Date.

                  Unimproved Area:  The Master Lease Property, less the
Main Building Area.

                  (b) Other  terms  shall have  meanings  ascribed  to such
terms in this Lease and as shown on  Schedule I attached  hereto and made a
part hereof.

                  SECTION 2.        LEASE OF MASTER LEASE PROPERTY

                  Landlord,   for  and  in   consideration  of  the  rents,
covenants and agreements  hereinafter reserved,  mentioned and contained on
the part of Tenant and its  successors  and assigns,  to be paid,  kept and
performed,  has leased, rented, let and demised, and by these presents does
lease,  rent,  let and demise unto Tenant,  and Tenant does hereby take and
hire,   upon  and  subject  to  the  covenants,   agreements,   provisions,
limitations and conditions herein expressed, the Master Lease Property.

                  SECTION 3.        TERM

                  (a) The initial term of this Lease (the  "Initial  Term")
shall be for a period of ten (10) years  commencing on the  Effective  Date
and  ending  at  11:59  p.m.  local  time on the day  preceding  the  tenth
anniversary of the Effective Date, unless

Version 10
       
<PAGE>
 
this  Lease  shall be  sooner  terminated  as  hereinafter  provided  or as
provided by law. Notwithstanding the foregoing, if the Term ends on any day
other than the last day of any calendar  month,  the Term shall be extended
so that the last  day of the Term is the last day of such  calendar  month.
The Initial  Term,  as may be extended  by  exercise of the  provisions  of
Subsection 3(b) or Section 28, may sometimes be collectively referred to in
this Lease as the "Term".

                  (b) Provided that no Event of Default  exists on the date
of the Holdover Notice or the date of commencement of the Holdover  Period,
Tenant may holdover  under the terms of this Lease with respect to the Main
Building Area for up to six (6) months  immediately after the Initial Term,
provided that:

                           (i)  Tenant provides Landlord with written notice
(the  "Holdover  Notice") at least six (6) months  prior to the  Expiration
Date of the  Initial  Term  stating the number of months up to six (6) that
Tenant will holdover under the terms of this Lease (the "Holdover Period");
and

                           (ii) Tenant pays as Base Rent for each month
during the Holdover Period,  in addition to all other amounts payable under
this Lease, one hundred twelve and 75/100ths  percent (112.75%) of the full
monthly installment of Base Rent due in the last year of the Initial Term.

If Tenant  exercises this holdover right,  then,  upon  commencement of the
Holdover Period,  any portions of the Unimproved Area remaining  subject to
this Lease at the  expiration  of the Initial Term shall  automatically  be
released from this Lease as Excluded  Area as if released  under Section 6;
provided,  however,  that after the  commencement  of the Holdover  Period,
Tenant shall not record any  instrument  confirming  the grant of easements
described in Section  6(d). At its sole  election,  Tenant may exercise its
right to the  Holdover  Period  with  respect  to less than all of the Main
Building  Area. If Tenant  desires to so holdover with respect to less than
all of the Main  Building  Area,  Tenant  shall  designate  in the Holdover
Notice the space in which it desires to holdover in the Main Building,  but
in no event less than two hundred  fifty  thousand  (250,000)  gross square
feet  (including the aggregate gross square footage of the area of the Main
Building then leased under Existing  Space Leases and Subleases,  the terms
of which have been extended  beyond the Expiration Date of the Initial Term
with Landlord's approval) (the "Holdover Space"). Tenant's payments of Base
Rent and payments of  Additional  Rent during the Holdover  Period shall be
reduced  to the  proportion  that  the  Holdover  Space  bears  to the Main
Building  Space and Tenant  shall have the  nonexclusive  right  during the
Holdover  Period to use the Parking  Areas,  access  drives,  and all other
common areas within the Main Building Area. If Tenant  designates a part of
the Holdover  Space in Building B in the Holdover  Notice,  Tenant shall be
required to holdover in the entirety of Building B. If Tenant  designates a
part of the Holdover Space in Building C in the Holdover  Notice,  Tenant

Version 10
<PAGE>
 
shall be required to holdover in the  entirety of Building C. The amount of 
square  footage  comprising  the Holdover  Space  designated in Building A 
shall be determined in accordance with the  applicable  standard of the 
Greater Washington Association of Commercial Realtors and such  Holdover
Space shall be so configured as to leave remaining space in Building A 
reasonably  marketable to third party tenants;  provided,  however,  this 
obligation  shall not require Tenant to construct Alterations in order to leave
such a marketable space.

                  (c). As used in this  Lease,  the term  "Lease  Year" means
each  consecutive  period of twelve (12)  calendar  months during the Term,
commencing on the Effective Date. If, however,  the Effective Date is other
than the first day of a calendar month, the first Lease Year shall begin on
the Effective Date and end on the first  anniversary of the last day of the
calendar month in which the Effective Date falls, and each succeeding Lease
Year shall be each  succeeding  consecutive  period of twelve (12) calendar
months thereafter during the Term.

                  SECTION 4.        RENT

                  (a) Tenant covenants and agrees to pay Landlord in lawful
money of the United States,  annual base rent for the Master Lease Property
("Base Rent") in twelve (12) equal monthly installments,  in advance, on or
before  the first  day of each and  every  month  throughout  the Term,  as
follows:

                  (i) FOUR MILLION NINE HUNDRED  SIXTY  THOUSAND AND NO/100
DOLLARS ($4,960,000.00) during the first Lease Year.

                  (ii) FIVE  MILLION  NINETY-SIX  THOUSAND AND FOUR HUNDRED
AND NO/100 DOLLARS ($5,096,400.00), during the second Lease Year.

                  (iii) FIVE MILLION TWO HUNDRED  THIRTY-SIX  THOUSAND FIVE
HUNDRED  FIFTY-ONE  AND NO/100  DOLLARS  ($5,236,551.00),  during the third
Lease Year.

                  (iv) FIVE MILLION  THREE  HUNDRED  EIGHTY  THOUSAND  FIVE
HUNDRED  FIFTY-SIX AND 15/100  DOLLARS  ($5,380,556.15),  during the fourth
Lease Year.

                  (v) FIVE MILLION FIVE HUNDRED TWENTY-EIGHT  THOUSAND FIVE
HUNDRED  TWENTY-ONE  AND 45/100 DOLLARS  ($5,528,521.45),  during the fifth
Lease Year.

                  (vi)  FIVE  MILLION  SIX  HUNDRED  EIGHTY  THOUSAND  FIVE
HUNDRED  FIFTY-FIVE  AND 79/100 DOLLARS  ($5,680,555.79),  during the sixth
Lease Year.

                  (vii) FIVE  MILLION  EIGHT  HUNDRED  THIRTY-SIX  THOUSAND
SEVEN HUNDRED  SEVENTY-ONE AND 07/100 DOLLARS  ($5,836,771.07),  during the
seventh Lease Year.


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                  (viii) FIVE MILLION NINE  HUNDRED  NINETY-SEVEN  THOUSAND
TWO HUNDRED EIGHTY-TWO AND 27/00 DOLLARS ($5,997,282.27), during the eighth
Lease Year.

                  (ix) SIX  MILLION  ONE  HUNDRED  SIXTY-TWO  THOUSAND  TWO
HUNDRED SEVEN AND 54/100  DOLLARS  ($6,162,207.54),  during the ninth Lease
Year.

                  (x) SIX MILLION  THREE  HUNDRED  THIRTY-ONE  THOUSAND SIX
HUNDRED  SIXTY-EIGHT AND 24/100 DOLLARS  ($6,331,668.24),  during the tenth
Lease Year.

Notwithstanding  the foregoing,  if the Effective Date shall be a day other
than the first day of a calendar  month,  there shall be due and payable on
the Effective  Date, as the  installment  of Base Rent for such  fractional
month,  an amount  determined by dividing the Base Rent for the first Lease
Year by 365 and  multiplying  the  result  by the  number  of days from the
Effective Date through the end of such month.

                  (b)  Tenant  also   covenants   and  agrees  to  pay,  as
additional rent (the  "Additional  Rent"),  all sums,  Impositions,  costs,
expenses and other  payments  which Tenant in any of the provisions of this
Lease  assumes,  agrees  or is  obligated  to pay,  or which  shall  become
otherwise  due and payable from Tenant to Landlord  under this Lease (other
than  Base  Rent).   Base  Rent  and  Additional   Rent  may  sometimes  be
collectively referred to herein as "Rent".

                  (c) It is the purpose  and intent of Landlord  and Tenant
that,  except as  explicitly  set  forth  herein,  the Base  Rent  shall be
absolutely  net to  Landlord,  so  that  this  Lease  shall  yield,  net to
Landlord, the net annual rent specified in Subsection (a) of this Section 4
in each  Lease  Year  during  the Term and that  all  costs,  expenses  and
obligations  of every kind and nature  whatsoever,  in  connection  with or
relating to the Master Lease Property shall be the obligation of Tenant and
shall be paid by Tenant.

                  (d) The Base Rent shall be paid to Landlord promptly when
due without notice or demand therefor, and without any abatement (except as
explicitly stated to the contrary in Section 8, Section 15 and Section 17),
deduction or set-off for any reason whatsoever.

                  (e) No  payment by Tenant or  receipt  or  acceptance  by
Landlord of a lesser  amount  than the  correct  Rent shall be deemed to be
other than a payment on account,  nor shall any endorsement or statement on
any check or any  letter  accompanying  any check or  payment  be deemed an
accord and  satisfaction,  and  Landlord  may accept  such check or payment
without  prejudice to Landlord's right to recover the balance or pursue any
other remedy in this Lease or as provided by law or in equity.



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                  (f) If any  of the  Rent  payable  under  the  terms  and
provisions  of this  Lease  shall be or become  uncollectible,  reduced  or
required to be refunded  because of any rent  control or similar act or law
enacted by a valid  governmental  authority,  Tenant  shall enter into such
agreements and take such other steps that  Landlord  may  request  and as may
be legally  permissible  to permit Landlord to collect the maximum  rents 
which,  from time to time during the continuance of such legal rent 
restriction, may be legally permissible (and not in excess of the amounts 
reserved therefor under this Lease).  Upon the termination of such legal rent
restriction,  (i) the Rent shall become and thereafter be payable in accordance
with the amounts  reserved  herein for the periods following such termination,
and (ii) Tenant shall promptly pay to Landlord, to the maximum extent legally
permissible,  an amount equal to (a) the Rent which would have been paid 
pursuant to this Lease but for such legal rent restriction,  less (b) the Rent
paid by Tenant during the period such rent restriction was in effect.

                  (g) All Rent and other  payments  required  to be made by
Tenant to Landlord shall be delivered to Landlord by wire transfer pursuant
to the wire transfer instructions as shown on Exhibit D attached hereto and
made a part hereof or to any other single  party that  Landlord may specify
from time to time by written notice given to Tenant.

                  (h)  In  recognition  of  the  extra  costs  to  Landlord
resulting from Tenant's  failure to make timely payment of any  installment
of Base Rent,  if any such  installment  is not paid  within  nine (9) days
after its due date,  the  delinquent  amount  shall be subject to a service
charge of five  percent  (5%) of such  delinquent  amount,  or such  lesser
charge as may be the maximum charge  permitted by law. In addition,  if any
installment  of Base Rent or any other sum due  Landlord  under  this Lease
remains unpaid  seventy-five  (75) days after its due date, the outstanding
amount  shall bear  interest at an annual rate of two percent (2%) over the
"Prime Rate" then prevailing or such lesser rate as may be the maximum rate
permitted by law (the "Stipulated  Rate"), and calculated from the due date
of such sum and  continuing  through the date such sum is paid in full.  As
used in this Lease,  the term "Prime Rate" means the prime rate of interest
for large money center banks as published in the Money Rates section of the
Wall Street  Journal or if the Wall Street  Journal  ceases to publish such
rate, as established  by reference to such other  authority as is generally
accepted in the business  community as a source for  determining the "Prime
Rate".

                  SECTION 5.        USE OF THE MASTER LEASE PROPERTY

                  (a) The Main  Building  may be occupied  and used for any
lawful purpose and shall not be used for any other  purpose.  The remainder
of the Main Building Area may be occupied and used for parking for, access to, 

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and other reasonable  purposes incidental to use of the  Main  Building  and
shall  not be used  for any  other  purpose.  The Unimproved  Area shall not
be  occupied by Tenant but may be used by Tenant for (i)  access  to the  Main
Building  Area  via  roads  existing  in the Unimproved  Area  as of the 
Effective  Date,  or as may  be  relocated  as expressly provided for in this
Lease, (ii) purposes which are incidental to use of the  Main  Building  Area,
such as use,  maintenance,  repair,  and replacement of utilities, storm 
drainage facilities, and signage serving or used in connection  with the Main
Building Area, (iii) use,  maintenance, repair, and replacement of antennae, 
satellite dishes, and other communications equipment located in the Unimproved
Area as of the Effective Date (but such facilities, excluding footings, 
foundations, and concrete bases, shall be removed by Tenant at its own expense
promptly after such Unimproved Area is excluded from this Lease under 
Section 6),  (iv)reasonable  recreation  uses,  such  as use of  the  existing
recreational facilities,  (v) temporary activities and uses that Tenant
reasonably deems desirable,  and (vi) such limited  purposes as are reasonably
necessary in order for Tenant to fulfill  its  obligations  under this Lease to
Care for the Unimproved Area.  Notwithstanding anything to the contrary
contained in this Lease,  with  respect to the uses  described  in clauses
(iv) and (v) above, (y) the Tenant shall ensure that such uses do not interfere
with the Development,  and (z) no action or  omission  of  Landlord,  or its
Agents, successors and assigns that interferes with such uses shall be a
default of Landlord under this Lease.

                  (b)      Tenant further agrees as follows:

                           (i)    Tenant and its Agents shall use the Master
Lease  Property  and  conduct  its  business  thereon  in a safe,  careful,
reputable and lawful manner.

                           (ii)   Tenant shall obtain, or cause to be obtained,
all   certificates,   licenses  and  permits  necessary  for  its,  or  its
subtenants',  occupancy, use, operation and maintenance of the Master Lease
Property.  Upon  reasonable  advance  request  by  Tenant,  Landlord  shall
reasonably  cooperate  with Tenant in  Tenant's  obtaining  such  necessary
certificates,  licenses or permits, including, without limitation,  signing
applications  for the same  within ten (10)  business  days after  Tenant's
request if Landlord's signing is required by Applicable Law or requested by
a governmental authority;  provided, that Landlord shall not be required to
incur any  out-of-pocket  costs to third parties in  connection  therewith.
Tenant  shall  promptly  reimburse  Landlord  for  any  of  its  reasonable
out-of-pocket costs to third parties for review or advice about such 
certificates, licenses or permits.

                           (iii)  Tenant shall not commit, nor allow to be
committed,  in, on or about the Master  Lease  Property,  any act of waste,
including  any act which might  deface,  damage or destroy any  improvement
thereon, or any part thereof. Further, Tenant shall not permit any noise or
odor to be emitted  from the Master  Lease  Property  which is  unlawful or
which constitutes a legal nuisance.  Notwithstanding the foregoing,  Tenant

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shall not have any responsibility for any waste, noise, or odor caused by
Landlord or its Agents.

                           (iv)   Tenant shall promptly comply in all material
respects  with all present and future laws,  statutes,  ordinances,  rules,
regulations and orders of any federal, state, municipal or other government
or  agency  thereof  having  jurisdiction  over  and  relating  to the use,
condition and occupancy of the Master Lease  Property,  and any  covenants,
conditions and restrictions of record existing as of the Effective Date and
governing the Master Lease Property (collectively,  the "Applicable Laws").
Tenant  acknowledges that the Applicable Laws are of public record and that
Tenant knows the character of its  operation on the Master Lease  Property.
Tenant  shall  have  sole   responsibility  for  its  compliance  with  the
Applicable  Laws in all material  respects,  and  Tenant's  inability to so
comply   shall  not  be  cause  for  Tenant  to   terminate   this   Lease.
Notwithstanding the foregoing:

                                    (A) Tenant shall not be required to comply
with any  Applicable  Laws to the extent  that  Tenant or the Master  Lease
Property are legally  grandfathered  or exempt from the application of such
Applicable  Laws or Tenant may obtain from the  appropriate  authorities  a
waiver or variance with respect to compliance.

                                    (B) Tenant shall not be required to comply
with any legal  requirements  in connection  with the Master Lease Property
arising out of or relating to the  Development or arising out of other acts
or  omissions  of Landlord  or its Agents on or with  respect to the Master
Lease Property. All of such requirements on the Master Lease Property shall
be promptly complied with by Landlord in all material respects,  at its own
expense.

                                    (C) Tenant shall not be obligated to 
correct any violations of Applicable Laws which may exist on the Master Lease
Property  as of the  Effective  Date,  except  to the  extent  specifically
required to do so by written notice from the governmental  authority having
jurisdiction.

                                    (D) Tenant shall have the right to contest
by appropriate legal proceedings,  conducted  diligently and in good faith,
without expense to Landlord,  the validity or application of any Applicable
Laws. If compliance  with the Applicable Law being contested may legally be
delayed  pending  the  prosecution  of the  proceeding,  Tenant  may  delay
compliance until the final determination of the proceeding.  Landlord shall
execute and deliver, within ten (10) business days after request by Tenant,
any appropriate  papers and/or other  instruments  that may be necessary to
permit Tenant to contest the validity or application of the Applicable Law.
Landlord shall otherwise  reasonably  cooperate with Tenant in the contest,
provided  that  Landlord  shall not be required to incur any  out-of-pocket
costs  to  third  parties  in  connection  therewith.  Notwithstanding  the

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foregoing, Tenant shall ensure that any such contest does not cause any lien 
to be filed against the Master Lease Property or any portion thereof.

                  SECTION 6. DEVELOPMENT; DESIGNATION OF THE EXCLUDED
                                     AREAS

                  (a)  Tenant  acknowledges  that,  among  other  purposes,
Landlord  purchased  the Master Lease  Property  for  possible  development
and/or sale of all or portions of the Unimproved Area. Although Landlord is
not  required to develop or sell any of the  Unimproved  Area,  Landlord is
contemplating a mixed-use  development thereon,  consisting of, among other
things, uses of varying densities, sizes and natures, and infrastructure in
order to serve same (all or any portion thereof,  the  "Development").  The
Development shall be at Landlord's sole cost. Tenant  acknowledges that the
Development  may require  Landlord to change the zoning  classification  as
well as take  other  actions to change  the land use and  character  of the
Master Lease Property.  Tenant covenants and agrees that during the Term it
shall not object to, and shall  reasonably  cooperate  with  Landlord  with
respect  to,  Development  by  Landlord  or  its  successors  of any of the
Unimproved Area and shall reasonably  cooperate so as to avoid interference
with the Development. Notwithstanding the foregoing:

                           (i)  The Development by Landlord shall not
interfere with Tenant's or its subtenants' use of the Master
Lease Property.

                           (ii) No rezoning or other development approvals
sought by Landlord for all or any part of the Master Lease  Property  shall
prohibit,  restrict,  or make  non-conforming  any of the uses which may be
conducted on the Main Building Area or Installations Premises under the I-3
zoning applicable to such property as of the Effective Date.

                           (iii)  Landlord acknowledges that the
uninterrupted   operation  of  antennae,   satellite   dishes,   and  other
communications  equipment  now  or in the  future  installed  on  the  Main
Building Area (the  "Communications  Facilities") is of critical importance
to  Tenant.  Landlord  shall  not  oppose  the  installation  or  continued
operation of the Communications
Facilities.

                           (iv)  Tenant shall not be required to incur any
liability  or  out  of  pocket   expense  to  third  parties  in  providing
cooperation to Landlord or its successors with respect to the Development.

                  (b) At any time  during the Term,  without any consent of
Tenant whatsoever,  a portion of the Unimproved Area shall be excluded from
the Master Lease  Property  immediately  upon the  occurrence of any of the
following (each a "Triggering Event"):


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                           (i)  A written notice from Landlord to Tenant
designating  such portion of the  Unimproved  Area as an Excluded Area. The
notice  shall be  accompanied  by a legal  description  and  drawing of the
Excluded Area.

                           (ii)  The transfer of record title to or the
ground lease of such portion of the Unimproved  Area by Landlord to another
party, including entities related to Landlord.

                           (iii)  The commencement of clearing or grading
work for such portion of the  Unimproved  Area (in which event the Excluded
Area shall include the land to be disturbed by the work, any borrow,  fill,
or stockpile  areas,  any areas for staging of equipment or materials,  any
areas upon which sediment control measures are to be implemented).

Landlord may cause  Triggering  Events with respect to as many  portions of
the Unimproved  Area,  and as often,  as Landlord may determine in its sole
and absolute  discretion.  Landlord shall give Tenant written notice of the
occurrence of the  Triggering  Events  described in (ii) and (iii) above at
least thirty (30) days before their  anticipated  dates of occurrence.  The
notice shall be accompanied by a legal description and plat of the Excluded
Area.  It is the  intention of (iii) that no  development  work  whatsoever
shall be performed to any portion of the  Unimproved  Area while it remains
subject to this Lease and that each such  portion  of the  Unimproved  Area
must be excluded from the Master Lease Property before work begins.

                  (c) Upon  exclusion  of an Excluded  Area from the Master
Lease  Property,  Tenant shall have no further rights or obligations  under
this Lease with respect to such Excluded Area.  There shall be no reduction
in Base Rent with  respect to an Excluded  Area,  but  Landlord  and Tenant
shall equitably apportion any Additional Rent with respect to such Excluded
Area as of the date of exclusion and Landlord shall reimburse Tenant at the
time of such  exclusion in an amount equal to (i) any  Impositions  paid by
Tenant,  and (ii) any other  expenses  paid by Tenant  (provided  that such
expenses  are  required to be paid by Tenant under this Lease) with respect
to such Excluded Area and attributable to the period of time beginning with
and  following  the  date  of  exclusion.  Such  reimbursement  shall  be a
condition precedent to exclusions of any property.  In addition,  Landlord,
at its sole  expense  and as a condition  precedent  to  exclusions  of any
property,  shall cause such Excluded Area to be  established  as a separate
tax parcel  for the  purposes  of  Impositions  at the time such  parcel is
excluded.

                  (d) In the event that an Excluded Area contains any road,
utility line,  drainage line,  storm water  management  facility,  sign, or
other  improvement or amenity then being used by Tenant in connection  with
the Main Building Area (collectively, "Appurtenances"), then, automatically
upon  exclusion  of the  Excluded  Area,  Tenant  shall be  deemed  to have
easements for the continued uninterrupted use of the

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Appurtenances  for so long as this Lease  remains in effect.  The easements
provided for in this subsection  shall include the right of Tenant to enter
upon the  Excluded  Area to  inspect,  maintain,  repair,  and  replace the
Appurtenances.  Notwithstanding  the  foregoing,  Landlord may  temporarily
discontinue  any  of the  Appurtenances  for a  period  of  not  more  than
forty-eight   (48)  hours  if  Landlord   provides  Tenant  with  temporary
Appurtenances,  provided such temporary  Appurtenances allow Tenant and its
Agents to use the Master Lease Property  without any material  diminishment
of Tenant's or its Agents' use of the Master Lease Property or any material
interference  with the business  operations of Tenant or its  subtenants on
the Main Building Area.

                  (e) Notwithstanding anything to the contrary contained in
this  Lease,  Tenant  shall  not be  required  to pay for any  incremental,
additional  or increased  Insurance or any  increased  costs of Care of the
Master Lease  Property which are  attributable  to Development or any other
acts or  omissions  of Landlord  or its Agents  with  respect to the Master
Lease Property.

                  (f)  In   addition   to  the   easements   for   existing
Appurtenances  provided for in  Subsection  6(d),  Landlord  shall grant to
Tenant, or to any utility company or governmental  authority  designated by
Tenant,   such  other   easements  for  utilities,   drainage,   stormwater
management,  and other similar matters on, under, and across the Unimproved
Area as may be reasonably  required in connection with the use or occupancy
of the Main Building Area and in  accordance  with this Lease  ("Additional
Easements").  No Additional Easements shall materially and adversely affect
the Development or materially  increase the cost of  Development.  Landlord
shall have a reasonable right of approval of the location of all Additional
Easements.  All Additional Easements shall be granted without charge within
ten (10) business days after written request by Tenant,  accompanied by the
instrument to be executed and a plat showing the location of the Additional
Easement.  Landlord  shall  make  good  faith and  commercially  reasonable
efforts to cause its  mortgagees  to  subordinate  their liens  against the
Master Lease Property to any Additional Easements.

                  SECTION 7.  TAXES AND IMPOSITIONS

                  (a) Tenant  covenants  and agrees to pay,  not later than
the first day on which any  interest or penalty  will accrue or be assessed
for the non-payment  thereof,  all of the following items  applicable to or
affecting the Master Lease Property or any part thereof accruing or payable
from and  after  the  Effective  Date  and  during  the Term or  applicable
thereto:  (i) all real estate  taxes and  assessments  (including,  without
limitation,  assessments  for special  business  improvement  or assessment
districts),  (ii) personal  property taxes,  (iii) occupancy and rent taxes
specifically imposed on tenants in Montgomery County or attributable to the
subtenants of Tenant,  (iv) water and sewer rents,  rates and charges,  (v)
vault taxes and charges,  (vi) certificate,  license and permit fees, (vii)
any taxes, assessments  or  governmental  levies,  general and special,

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ordinary and extraordinary,  foreseen and unforeseen,  of any kind and nature
whatsoever which at any time prior to or during or  applicable to the Term or
any part thereof may be assessed, levied, confirmed, imposed upon, or grow or
accrue or become due and payable out of, or charged  with  respect to, or
become a lien on, the Master Lease Property or any part thereof, or the
sidewalks or streets in front of or adjoining the Master Lease  Property,  or
any vault, passageway or space in, over or under such sidewalk or street, or
any other appurtenances  to the Master  Lease  Property,  or any  personal
property, equipment or other  facility used in the operation  thereof,  or any
use or occupation  of the Master Lease  Property,  or any document by which
Tenant creates or transfers an interest or estate in the Master Lease Property
(except  any  document  releasing  an Excluded  Area from the Master  Lease
Property), and (vii) any fines or penalties or similar governmental charges
applicable with respect to any of the foregoing, together with interest and
costs  thereon (all such items  aforesaid  may  sometimes  be  collectively
referred to herein as "Impositions").

                  (b) If, by law, any  Imposition  imposed during the Term,
which is an assessment not related to general real estate taxes, may at the
option of the  taxpayer be paid in  installments  (whether or not  interest
shall accrue on the unpaid balance of such Imposition), Tenant may exercise
the option to pay the same (and any accrued  interest on the unpaid balance
of such  Imposition)  in  installments  and, in such event,  shall pay such
installments plus interest as may become due during the Term of this Lease;
provided,  that all such payments shall be made before any fine, penalty or
other charge for non-payment of any installment may be added thereto.

                  (c) Any Imposition (including,  without limitation, those
Impositions  which have been converted into installment  payments by Tenant
as referred to in Subsection (b) above)  relating to a period of time which
is partially within the Term and partially beyond the Expiration Date shall
be adjusted  between  Landlord and Tenant as of the Expiration Date so that
Landlord shall pay that portion of such Imposition which is attributable to
any  period of time  after the  Expiration  Date and  Tenant  shall pay the
remainder thereof. This subsection shall survive termination of the Lease.

                  (d)  Notwithstanding  the foregoing,  Tenant shall not be
required to pay municipal, state or federal income, excess profits, capital
levy,  rental  (except  as set forth in clause  (iii) of  Subsection  (a)),
estate,  succession,  inheritance,  transfer,  recordation  (except  to the
extent described in Section 30(v)) or gift taxes of Landlord, any corporate
franchise  tax imposed  upon  Landlord  or any tax  imposed  because of the
nature of the business entity of Landlord;  provided,  however,  that if at
any time  during  the  Term,  the  method  of  taxation  prevailing  at the
Effective  Date shall be altered so that,  in  substitution  for ad valorem
real estate taxes, any new Imposition or charge, or any part thereof, shall be

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measured by or be based in whole or in part upon the Master Lease Property and
shall be imposed upon Landlord, then all such new  Impositions  or charges,
or any part  thereof,  shall be deemed to be included within the term
"Impositions",  and Tenant shall pay and discharge the same as herein provided
in respect of the payment of Impositions.

                  (e) (i) If permitted by  Applicable  Law, and provided no
Event of Default is then in existence,  Tenant shall have the right, at its
own expense, to contest the amount or validity, in whole or in part, of any
Imposition by appropriate  proceedings  diligently conducted in good faith.
If, under  Applicable  Law, the  contested  Imposition  must be paid before
undertaking the contest,  Tenant shall pay such  Imposition  (which payment
may be made under protest, at Tenant's option) or, if permitted by Landlord
and any mortgagee of Landlord (including trustees or beneficiaries of deeds
of trust)  ("Mortgagee"),  either deposit with  Landlord,  Mortgagee or the
assessing  body, as Landlord,  Mortgagee or the assessing body may require,
an amount  sufficient  to pay all amounts  referred to in  Subsection  (ii)
below,  or undertake such other method of securing  payment of such amounts
as is satisfactory to Landlord, Mortgagee and the assessing body.
                      (ii)     Upon the termination of any such proceeding,
Tenant shall pay the amount of such  Imposition  or part thereof as finally
determined as due in such  proceedings,  the payment of which may have been
deferred  during the  prosecution  of such  proceedings,  together with any
costs,  fees,  interest,  penalties  or  other  liabilities  in  connection
therewith,  and, upon such payment,  Landlord  shall,  provided an Event of
Default is not then in existence, return or request Mortgagee to return any
amount still on deposit with it or with Mortgagee with respect to such paid
Imposition.  If at any time  during  the  continuance  of such  proceedings
Landlord,  Mortgagee or the assessing body shall deem the amount  deposited
or the undertaking insufficient,  Tenant shall, upon thirty (30) days prior
written  notice,  make an additional  undertaking or deposit with Landlord,
Mortgagee or the assessing  body, as Landlord or Mortgagee  reasonably  may
request,  or as the assessing body may require,  and upon failure of Tenant
to do so, the amount  theretofore  deposited  shall be applied by Landlord,
Mortgagee or the  assessing  body to the payment,  removal and discharge of
such Imposition and the interest and penalties in connection  therewith and
any costs, fees (including, without limitation,  reasonable attorneys' fees
and  disbursements) or other liabilities  accruing in any such proceedings,
and the balance, if any, shall be returned to Tenant, or the deficiency, if
any, shall be paid by Tenant immediately on demand of Landlord or Mortgagee
to  the  taxing  authority  to  which  such  Imposition  is  payable.  This
subsection shall survive termination of this Lease.

                  (f)  Landlord  or  Tenant  may,  if it shall  so  desire,
endeavor  at any  time or  times  to  obtain  a  lowering  of the  assessed
valuation  upon the Master Lease  Property,  or any part  thereof,  for the
purpose of reducing Impositions thereon, and in such event, the other party


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will reasonably cooperate in effecting such reduction, but shall not be 
required to incur any out-of-pocket costs in so cooperating.

                  (g)  Landlord  shall  not  be  required  to  join  in any
proceedings  referred to in Subsection  (e) above unless the  provisions of
any law,  rule or  regulation at the time in effect shall require that such
proceedings  be brought by or in the name of  Landlord  or any owner of the
Master  Lease  Property,  in  which  event,  Landlord  shall  join  in such
proceedings or permit the same to be brought in its name and shall sign all
documents reasonably necessary to prosecute the proceedings. Landlord shall
not be subject to any liability for the payment of any costs or expenses in
connection  with any such  proceedings,  and Tenant will indemnify and save
harmless Landlord from and against any such costs and expenses,  including,
but not limited to, reasonable attorneys' fees and disbursements,  and from
any  liability  resulting  from  such  proceeding.  After  reimbursing  and
indemnifying  Landlord for the items referred to in the preceding sentence,
Tenant shall be entitled to any refund with respect to any  Imposition  and
penalties  or  interest  thereon  which  have been paid by Tenant  (whether
directly or through  escrowed  funds),  or which have been paid by Landlord
but previously reimbursed in full to Landlord by Tenant.  Tenant's right to
the refund shall survive termination of this Lease.

                  (h) The certificate,  advice,  statements, or bill of the
appropriate  official  designated  by law to make or  issue  the same or to
receive  payment of any  Imposition  shall be prima facie evidence that the
Imposition  is due and unpaid at the time of the making or issuance of such
certificate, advice statement or bill.

                  (i)  Tenant  shall  make  all  payments  of   Impositions
directly to the appropriate governmental authorities, and Landlord appoints
Tenant  the  attorney-in-fact  of  Landlord  for the  purpose of making all
payments  to be made by Tenant  pursuant to any of the  provisions  of this
Lease to persons or  entities  other than  Landlord.  In case any person or
entity  to whom any sum is  directly  payable  by  Tenant  under any of the
provisions  of this  Section 7 shall  refuse to accept  payment of such sum
from Tenant,  Tenant shall  thereupon  give written  notice of such fact to
Landlord and shall pay such sum  directly to Landlord  and  Landlord  shall
promptly pay such sum to such person or entity.

                  (j) Tenant shall deliver to Landlord  duplicate  receipts
or photostatic copies thereof, or other evidence reasonably satisfactory to
Landlord  (followed by such duplicate  receipts or copies,  when available)
showing the payment of all Impositions, within ten (10) business days after
the  respective  payments  are  required to be made by Tenant and  Landlord
requests such evidence in writing.

                  (k)  Landlord  shall  furnish  to  Tenant  copies  of all
notices of assessment  and bills  relating to  Impositions  within ten (10)
business days after Landlord receives any of the same from the governmental
authorities.

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                  SECTION 8.        UTILITIES

                  (a) Tenant  agrees to pay all  charges  made  against the
Master  Lease  Property  for  gas,   heat,   water,   electricity,   sewage
disposition,  telephone and all other utilities and services related to the
Master Lease Property during the Term (collectively, the "Utilities").

                  (b) Tenant understands,  acknowledges and agrees that any
one or more of the Utilities may be  interrupted or diminished by reason of
causes  beyond  Landlord's  reasonable  control;  that  Landlord  does  not
represent or warrant the uninterrupted avail ability of the Utilities; that
Tenant shall be solely responsible for obtaining and maintaining the use of
the Utilities;  and that, unless caused by Landlord or its Agents, any such
interruption  or  diminishment  shall  not (i) be  deemed  an  eviction  or
disturbance  of  Tenant's  right to  possession,  occupancy  and use of the
Master Lease Property or any part thereof,  or (ii) render  Landlord liable
to Tenant in damages by abatement of Rent or otherwise,  or relieve  Tenant
from the obligation to perform its covenants  under this Lease. In pursuing
the  Development,  Landlord  shall  take and cause its  Agents to take best
efforts to avoid the interruption or diminishment of the Utilities.

                  SECTION 9.        SIGNS

                  (a) Tenant shall not  inscribe,  paint,  affix or display
any sign,  advertisement or notice (collectively "Signs") on any portion of
the Main  Building  Area (or on any interior  portion of the Main  Building
that is visible from the exterior) not presently  located  thereon  without
the  prior  written  consent  of  Landlord,  which  consent  shall  not  be
unreasonably withheld or delayed.

                  (b) Tenant shall not  inscribe,  paint,  affix or display
any  Sign on any  portion  of the  Unimproved  Area not  presently  located
thereon without the prior written consent of Landlord,  which consent shall
be in Landlord's  sole and absolute  discretion.  After a Triggering  Event
with respect to an Excluded  Area on which any Sign then  exists,  Landlord
shall have the right, at its sole expense, to remove such Sign. If any Sign
is to be removed pursuant to the preceding sentence, Landlord, if requested
by Tenant, shall relocate the Sign, and any lighting and electrical service
related to the Sign,  to another  location  reasonably  agreed  upon by the
parties and providing  substantially similar visibility to that afforded by
the prior location.

                  (c)  Despite  the  foregoing,  Tenant  shall not  require
Landlord's  consent to replace any Sign existing as of the  Effective  Date
provided that the dimensions and location of the new Sign are substantially
the same as those of the existing Sign.



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                  SECTION 10.       AS-IS CONDITION OF MASTER LEASE PROPERTY

PRIOR TO THE EFFECTIVE DATE, TENANT OWNED THE LAND FOR APPROXIMATELY THIRTY
(30) YEARS,  DEVELOPED THE IMPROVEMENTS THEREON,  INCLUDING BUT NOT LIMITED
TO THE MAIN BUILDING,  AND OCCUPIED THE MAIN BUILDING.  CONSEQUENTLY,  UPON
THE EFFECTIVE  DATE,  TENANT SHALL ACCEPT THE MASTER LEASE  PROPERTY IN "AS
IS" CONDITION.  TENANT AGREES AND  ACKNOWLEDGES  THAT LANDLORD HAS NOT MADE
ANY  REPRESENTATION  RESPECTING  OR ANY  WARRANTY  WHATSOEVER,  EXPRESS  OR
IMPLIED,   REGARDING  THE  MASTER  LEASE   PROPERTY,   INCLUDING,   WITHOUT
LIMITATION,  REPRESENTATIONS OR WARRANTIES REGARDING THE PHYSICAL NATURE OR
CONDITION  OF THE MASTER LEASE  PROPERTY.  TENANT  ACKNOWLEDGES  THAT IT IS
COGNIZANT OF AND SATISFIED  WITH ALL ASPECTS OF THE MASTER LEASE  PROPERTY,
AND THAT AS PROVIDED HEREIN THIS TRANSACTION IS AN "AS IS" TRANSACTION.

                  SECTION 11.       REPAIRS, MAINTENANCE AND MANAGEMENT

                  (a) Tenant shall,  at its sole expense,  keep,  maintain,
manage and operate (collectively,  "Care" or "Care for" or "Care of" as the
context may require) the Main Building Area in good condition and repair in
a manner consistent with Care for Class B suburban buildings of similar age
and character and used for similar purposes in Montgomery County,  Maryland
("Comparable Buildings"), and in compliance with all Applicable Laws in all
material respects.  Except as otherwise  provided in Subsection  5(b)(iii),
Subsection  5(b)(iv)(A),  Subsection  5(b)(iv)(B),  Subsection 5(b)(iv)(C),
Subsection  5(b)(iv)(D),  Subsection 8(b),  Section 10,  Subsection  11(a),
Subsection  11(c),  Subsection  11(d),  Subsection  12(a),  Subsection  15,
Subsection 16(b),  Subsection 17(a)(i),  Subsection 17(a)(iii),  Subsection
17(b), Section 23, Subsection 27(b),  Subsection 27(f) of this Lease to the
contrary,  Tenant  shall make and perform  all  necessary  maintenance  and
repairs to the Main Building Area, whether  structural and  non-structural,
ordinary and extraordinary,  foreseen and unforeseen, of every nature, kind
and description.  All repairs made by Ten ant shall be reasonably suited to
accomplish  their  intended  purposes  and  shall  be  in  compliance  with
Applicable Laws in all material respects.  The necessity for or adequacy of
Care  shall  be  measured  by  the  standards  which  are  appropriate  for
Comparable  Buildings;  provided,  that Tenant  shall in any event make all
repairs  necessary to avoid structural damage to the Main Building or other
damage or injury to  persons,  property  and other  portions  of the Master
Lease  Property.  However,  Landlord shall be  responsible  for any repairs
necessitated by Landlord or its Agents.

                  (b) Tenant shall  further  Care for the  remainder of the
Master Lease  Property and keep the same in good  condition and repair in a
manner  consistent  with other similar  properties  in  Montgomery  County,
Maryland (the "Comparable  Properties") and in material compliance with all
Applicable Laws. All repairs made by Tenant shall be reasonably suitable to
accomplish  their  purposes  and  shall  be  in  material  compliance  with
Applicable Laws. Tenant shall in any event make all repairs necessary to

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avoid structural damage to the improvements or other damage or injury to
persons, property and other portions of the Master Lease  Property.  However,
Landlord shall be  responsible  for any repairs necessitated by Landlord or its
Agents. Further, Tenant, while it was owner of the  Property,  recorded a
Declaration  of  Easements,  Covenants,  and Restrictions (the  "Declaration")
which, among other things,  sets forth a standard of Care for the Master Lease
Property.  Landlord hereby  delegates to Tenant,  and Tenant hereby accepts
from Landlord,  the  maintenance  and repair obligations applicable to the
Master Lease Property and described in Section 6 of the Declaration.

                  (c) If any  dispute  shall  arise  between  Landlord  and
Tenant as to the  standard of Care  required  under  Subsection  (a) or (b)
above,  the matter shall be resolved by binding  arbitration  in accordance
with the  then  prevailing  Commercial  Arbitration  Rules of the  American
Arbitration  Association (the "AAA"). Upon demand for arbitration by either
party in  accordance  with such  rules,  the  matter  shall be decided by a
single arbitrator in Montgomery  County,  Maryland,  selected in accordance
with the prevailing  Commercial  Arbitration  Rules of the AAA. In deciding
any matter  relating to the Main Building Area,  the arbitrator  shall take
into account the age and character of the Main  Building,  the standards of
Care set forth in this  Section 11, and the  remaining  Term of this Lease.
The arbitrator  shall hold a hearing on the matter within  forty-five  (45)
days after he or she is  appointed.  At least  twenty  (20) days before the
hearing,  each party shall submit to the other party a written statement of
its case,  copies of all  documents  upon  which it  intends to rely at the
hearing,  and a list of the  witnesses it intends to call to testify at the
hearing.  The hearing shall be concluded within fifteen (15) days after the
initial  hearing date and the  arbitrator  shall  decide the matter  within
fifteen  (15) days after the hearing is  concluded.  The  arbitrator  shall
render his or her  decision in writing,  setting  forth the reasons for the
decision.  Each party shall bear its own costs related to the  arbitration,
except that the parties shall share equally all filing fees and other costs
imposed by the AAA in connection  with the  arbitration and the fees of the
arbitrator.   The   decision   of  the   arbitrator   shall  be  final  and
non-appealable  and judgment on the decision may be entered in any court of
competent jurisdiction.

                  (d)  Notwithstanding  Subsections  (a)  and  (b),  unless
required by Applicable  Laws,  Tenant shall not be required to (i) improve,
upgrade,  re-model,  retrofit,  or  renovate  all or any  part of the  Main
Building  Area  or  (ii)  make  any  replacement  or  major  repair  of any
component,  element or system of the Main  Building Area where a more minor
repair may be  sufficient  to allow the ordinary  use and  occupancy of the
Main Building Area.

                  (e) In addition to the Care  required by this Section 11,
Tenant, at its sole expense, within five (5) years after the Effective Date
(subject to extension for Unavoidable Delays), shall complete the work (the
"Roof Work") described in Exhibit F attached hereto and made a part hereof.

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                  (f)  Landlord  agrees that during the Term,  Tenant shall
have the right,  after  providing  prior  written  notice to  Landlord,  to
enforce any rights of Landlord  under  applicable  warranties,  guarantees,
licenses and permits  applicable to the Main Building Area.  Landlord shall
sign such  documents  and  otherwise  reasonably  cooperate  with Tenant to
facilitate such  enforcement,  provided that Landlord shall not be required
to incur any out of pocket expense to third parties in so doing.

                  SECTION 12.       ACCESS TO MASTER LEASE PROPERTY

                  (a) Tenant  acknowledges  that Landlord has a significant
economic  interest in the Care of the Main Building Area and that Landlord,
pursuant  thereto,  has a need,  from  time to time,  to  inspect  the Main
Building  Area to insure  Tenant's  conformity  with the  covenants of this
Lease.  Tenant,  therefore,  hereby  authorizes  Landlord  and any  parties
authorized  by Landlord to perform such  inspections  of the Main  Building
Area as  Landlord  from  time  to time  may  reasonably  deem  appropriate.
Landlord  shall have the right to enter any part of the Main  Building Area
at all  reasonable  times,  upon  reasonable  advance  notice to Tenant and
accompanied by a representative of Tenant,  for the purposes of making such
inspections,  showing the Main  Building  Area to  prospective  purchasers,
investors,  mortgagees and tenants, and making such repairs, alterations or
improvements  to the Main Building  Area as Landlord may deem  necessary or
desirable  if Tenant  fails to  properly  Care for same  after  notice  and
opportunity to cure as provided for in Section  21(a).  No such entry shall
materially  interfere  with the use and occupancy of the Main Building Area
by Tenant, its subtenants and licensees.  Landlord shall incur no liability
to Tenant for such entry  except in the case of death,  bodily  injury,  or
property  damage  caused by  Landlord or its  Agents.  Notwithstanding  the
foregoing, Landlord shall have no right to enter upon those portions of the
Main  Building  which  are  secured  or  confidential   areas  pursuant  to
Applicable  Laws or  agreements  to which  Tenant is  subject  ("Restricted
Areas").  Further,  no person who is a foreign  national may enter into the
Main  Building  on behalf of  Landlord,  unless  approval of such person is
obtained from Tenant in advance.  Such approval may be withheld only to the
extent entry by such person would violate  Applicable Laws or agreements to
which Tenant is subject.

                  (b)  Tenant  also   acknowledges   that  Landlord  has  a
significant  economic  interest in the Care of the Unimproved  Area, and an
on-going need to access the Unimproved Area in connection with Development.
Tenant, therefore, hereby authorizes Landlord and any parties authorized by
Landlord to enter upon the  Unimproved  Area at any time without notice and
without being  accompanied by a representative  of Tenant,  to perform such
inspections  of the  Unimproved  Area as  Landlord  from  time to time  may
reasonably deem  appropriate,  and further to perform  whatever  activities
Landlord  deems  necessary or  desirable,  in its sole  discretion,  to aid
Development,  provided  that such  activities do not amount to a Triggering
Event. Additionally, Tenant

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authorizes  Landlord  and any  parties  authorized  by  Landlord to use and
maintain  such  then  existing  roads  and  other   infrastructure  in  the
Unimproved Area, and to grant such easements and rights of way with respect
to the  Unimproved  Area as Landlord deems  necessary or desirable,  in its
sole  discretion.  However,  Landlord's  exercise of its rights  under this
Subsection 12(b) shall not materially  interfere with the use of, or access
to, the Unimproved  Area or the Main Building Area by Tenant or its Agents.
No development or construction work shall take place in the Unimproved Area
unless such Unimproved Area is first excluded from this Lease in accordance
with Section 6.

                  SECTION 13.       ALTERATIONS AND PERSONAL PROPERTY

                  (a) Except as required by Tenant's repair and maintenance
obligations  under  this  Lease,  Tenant  shall  not make any  alterations,
additions,  installations  or  other  improvements  ("Alterations")  to the
Master Lease Property or any part thereof without the prior written consent
of Landlord,  which consent shall not be  unreasonably  withheld or delayed
with  respect  to the Main  Building  Areas but which  may be  withheld  in
Landlord's sole discretion  with respect to the Unimproved  Area.  However,
nothing in this Section shall be deemed to diminish  Landlord's  obligation
to grant  easements  under Section 6(e) or Tenant's  right to replace Signs
under Section 9(d). Moreover,  Tenant need not seek the consent of Landlord
to (i) install any Alteration in the Main Building Area costing One Hundred
Seventy  Thousand  Dollars  ($170,000.00)  or less, (ii) install any tenant
improvement  work for subleased  space in the Main Building,  (iii) install
communications  equipment on the roof of the Main Building (the "Roof Based
Facilities") (provided any such piece of the Roof Based Facilities does not
exceed  twenty (20) feet in  diameter),  or (iv)  dismantle  and remove any
clean  room  contained  in the Main  Building  (collectively,  "Preapproved
Alterations"). Notwithstanding anything to the contrary herein, in no event
shall  Tenant make any  Alterations  which would  affect the  structure  or
structural  integrity  of the  Main  Building  or the  facade  of the  Main
Building or construct or place any communications equipment on the exterior
of the Main Building or other  exterior  portions of the Main Building Area
(except the Roof Based Facilities  described in clause (iii) above) without
obtaining the prior written consent of Landlord, which consent shall not be
unreasonably  withheld or delayed. Any Alteration in or to the Master Lease
Property,  whether or not  requiring  the  approval of  Landlord,  shall be
subject, however, in all cases to the following:

                      (i)     Except to the extent that any Alteration is a
Preapproved  Alteration,  no  Alteration  shall be made without at least 30
days prior notice to Landlord (unless  Applicable Laws require otherwise or
except  in the case of an  emergency,  in which  case,  Tenant  shall  give
Landlord as much notice as is  practicable),  accompanied  by a copy of the
proposed  plans and  specifications  in detail  reasonably  sufficient  for
Landlord to review same, the identity of the contractor and any

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subcontractors, and a copy of all contracts with respect to the Alteration.
All  Alterations  shall be made  promptly  at the sole cost and  expense of
Tenant and in a good and workmanlike manner and in material compliance with
all Applicable Laws. Tenant shall promptly  reimburse Landlord upon demand,
up to One Thousand  Dollars  ($1,000) in each instance,  for any reasonable
costs and expenses incurred by Landlord to third parties in connection with
Landlord's  review  of  Tenant's  proposed  plans  and  specifications,  or
revisions thereof  (collectively,  the "Plans");  provided,  however,  that
Tenant shall not be obligated to reimburse  Landlord for Landlord's  review
of any Plans in connection with Restoration  (except as provided in Section
15). Upon the request of Landlord,  but not more than once each Lease Year,
Tenant shall provide  Landlord with a written  description  of  Alterations
made to the Master Lease Property  since the later of (i) the  Commencement
Date, and (ii) the date of the last such report. In addition,  Tenant shall
provide "CAD" drawings to Landlord showing the current configuration of the
Main Building,  including,  without limitation, any Alterations made to the
Master  Lease  Property.  Such  drawings  shall be  delivered  to  Landlord
approximately twenty-four (24) months before the Expiration Date and within
thirty (30) days after the expiration or earlier termination of this Lease.

                      (ii)     The Master Lease Property at all times shall
be kept by Tenant free of liens for labor and materials supplied or claimed
to have been supplied to the Master Lease  Property in connection  with the
Alterations.

                      (iii)    Notice is hereby given that Landlord shall
not be  liable  for any  labor or  materials  furnished  to or for  Tenant.
Furthermore,  notice is  hereby  given to Tenant  and  Tenant's  mechanics,
laborers and materialmen  with respect to the Master Lease Property that no
mechanic's,  materialman's  or laborer's lien shall attach to or affect the
reversion or other interest of Landlord in or to the Master Lease Property.

                      (iv)     No Alteration shall, when completed, be of
such a  character  as to  render  any  part of the  Master  Lease  Property
anything other than a complete, self-contained structural unit.

                      (v)      Worker's compensation, builder's risk and
general  liability  insurance with respect to the Alteration as required by
Section 14 shall be maintained by Tenant.

                      (vi)      All Alterations, other than roof-top
communications  equipment,  shall be the property of Landlord. Tenant shall
have  no  obligation  to  remove,  or  to  pay  for  the  removal  of,  any
Alterations, other than roof-top communications equipment, upon termination
of this Lease.

                  (b) All personal property, including, but not limited to,
trade fixtures,  furniture,  furnishings,  telephone  switching  equipment,
roof-top communications equipment, generators and

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uninterrupted  power supply equipment,  and moveable  equipment  ("Personal
Property")  owned by Tenant,  and all Restricted  Property,  upon or in the
Master Lease Property shall remain the property of Tenant,  or remain under
Tenant's  control,  and shall be removed  by  Tenant,  at its sole cost and
expense,  upon  termination  of this  Lease or  surrender  by Tenant of the
Master Lease Property to Landlord.  (The term "Personal  Property" does not
include Fixtures and Limited  Personal  Property as defined in the Purchase
and Sale  Agreement.)  If such  removal  shall  injure or damage the Master
Lease  Property,  Tenant  shall  repair  the  damage  at its sole  cost and
expense,  reasonable  wear and tear excepted.  If Tenant fails to so remove
and repair,  Landlord shall have the right to remove the Personal  Property
and Restricted Property and to dispose of the same and to repair the Master
Lease Property without  accountability to Tenant,  and at the sole cost and
expense of  Tenant.  The  "Restricted  Property"  shall  mean all  personal
property,  including, but not limited to documents and equipment, which are
required to be secured or kept confidential  pursuant to Applicable Laws or
agreements to which Tenant is subject. The Restricted Property shall at all
times,  both  during  and  after the Term,  be the sole  responsibility  of
Tenant.  Tenant  covenants and agrees that no Restricted  Property shall be
left in or upon the Master Lease Property  after  termination of this Lease
or surrender by Tenant of the Master Lease  Property to Landlord.  Upon the
expiration  or  earlier  termination  of this  Lease  (or,  in the  case of
Excluded  Areas,  at the time such areas are excluded from the Master Lease
Property) all right,  title and interest to any  underground  storage tanks
located in the Master Lease  Property  (or, in the case of Excluded  Areas,
located in such  Excluded  Areas)  shall  automatically  convey to Landlord
without the  requirement  that either party execute any other  documents to
effectuate the conveyance and shall become part of Landlord's property.

                   SECTION 14.      INSURANCE

                  (a) At all times during the Term, Tenant, at its own cost
and  expense,  shall carry and maintain  the  insurance  coverage set forth
below (the "Insurance"):

                           (i)   Hazard insurance covering the Master Lease
Property (including,  without limitation,  all Alterations now or hereafter
made to the Master Lease  Property)  under an "All Risks of Physical  Loss"
policy (an "All  Risks  Policy")  written  with full  replacement  coverage
("Replacement  Value"),  i.e., in an amount equal to 100% of the full costs
of  replacement  of the  insurable  portions of the Master Lease  Property,
excluding  foundation and excavation  costs and subject to such  reasonable
deductibles  as  Tenant  may see fit to carry  and as  Landlord  reasonably
approves.  For the  purposes  of this  Section  14,  deductibles  up to the
amounts stated on Schedule II attached hereto shall automatically be deemed
reasonable  deductibles  without  any need  for  Landlord's  approval.  The
insurer's   determination  of  Replacement   Value  shall  be  binding  and
conclusive on Landlord and Tenant. A stipulated value or agreed

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amount endorsement deleting the co-insurance  provision of the policy shall
be provided with such insurance.  If not otherwise  included within the All
Risks Policy specified above, Tenant shall carry or cause to be carried, by
endorsement  to such All Risks Policy,  coverage  against (i) damage due to
water and sprinkler leakage, with limits of coverage reasonably required by
Landlord,   and  (ii)  building   ordinance  covering  increased  costs  of
construction with a limit of not less than twenty-five percent (25%) of the
value of the Main  Building  Area and  demolition  with a limit of not less
than  ten  percent  (10%)  of the  value of the  Main  Building  Area.  The
Replacement Value shall include the cost of debris removal and the value of
grading,   paving  and  landscaping,   and   architects',   engineers'  and
development fees.  During the course of any Alteration,  Tenant shall carry
insurance in the form of a "Builder's  Risk" policy with respect thereto in
such amount as reasonably required by Landlord.

                  (ii) Commercial  liability  insurance with respect to the
Master Lease Property and the operations related thereto, whether conducted
on or off the Master Lease Property,  against  liability for death,  bodily
injury, and property damage (the "Liability Policy").  The Liability Policy
shall be on an occurrence basis and specifically shall include:

                              (A) Contractual liability to cover Tenant's
obligations to indemnify Landlord as required under this Lease; and

                              (B) Water damage and sprinkler  leakage legal
liability.

The  Liability  Policy shall be written for a combined  single limit of not
less than Ten Million Dollars ($10,000,000). Such limit shall be subject to
reasonable  increase  from  time to time  (but not  more  than  once  every
twenty-four   (24)  months)  in  accordance  with  the  limits  then  being
customarily  carried with respect to Comparable  Buildings  and  Comparable
Properties,  or operations  similar to those being  conducted on the Master
Lease  Property.  Tenant may satisfy the required  coverage  limits for the
Liability  Policy by carrying a combination of primary and excess liability
policies providing  aggregate coverage in at least the limits stated herein
for such policy.

                 (iii) Boiler and machinery insurance with limits as from time
to time customary for Comparable  Buildings and appropriate in the light of the
cost of repairing potential damage.

                 (iv)  Rent loss insurance ("Rent Insurance") on the "All Risks
of Physical  Loss" basis in an amount  equal to  twenty-four (24) months of
the then current Base Rent.

               (b)  Tenant further covenants and agrees, at its sole cost
and expense, to procure and maintain or cause to be procured and maintained
at all times all necessary worker's compensation

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insurance  covering all persons  employed by Tenant,  Existing  Tenants and
Subtenants in and about the Master Lease Property.

               (c)  Tenant further covenants and agrees, at its sole cost
and expense, to procure and maintain or cause to be procured and maintained
at  all  times  Comprehensive  Automobile  Insurance  covering  all  owned,
non-owned,  and hired  automobiles of tenant in limits of not less than One
Million Dollars ($1,000,000).

                (d)  In  addition  to the  insurance  carried  by  Tenant,
during the course of any Alteration or Care work undertaken by a contractor
hired by or for Tenant,  Tenant  shall  require  such  contractor  to carry
public  liability  insurance in limits of not less than Two Million Dollars
($2,000,000).

                (e)  Tenant  may  at its  option  provide  any  Insurance
coverage under a blanket  insurance  policy instead of a separate policy or
policies,  provided that the certificate or certificates  issued under such
blanket  insurance policy,  and the coverage afforded thereby,  conforms in
all respects to the requirements hereof (a "Blanket Policy").

                (f)  Tenant  acknowledges  that it currently carries flood
and  earthquake  coverage  ("Flood and Earthquake  Insurance").  Tenant not
shall not be required to maintain the Flood and Earthquake Insurance during
the Term;  provided,  however,  Tenant shall give  Landlord at least thirty
(30)  days  written  notice  prior to any  discontinuance  of the Flood and
Earthquake Insurance.  Notwithstanding the foregoing, (i) in the event that
any portion of the Property is classified as being located in (A) a Class A
flood  zone or any  other  flood  zone  indicating  a higher  frequency  of
predicted  flooding  than a Class A flood zone as  indicated by the Federal
Emergency  Management Agency (a "Flood Zone"), or (B) a B3 seismic activity
zone or any other seismic  activity zone  indicating a higher  frequency of
predicted  seismic activity than B3 seismic activity zone as indicated by a
consensus of  insurance  underwriters  that  underwrite  such  policies for
earthquake coverage (a "Seismic Activity Zone"), Tenant shall procure Flood
and  Earthquake  Insurance  if such  coverage is customary  for  Comparable
Buildings and Comparable Properties, or (ii) to the extent the Master Lease
Property is insured under a Blanket Policy and such Blanket Policy contains
Flood and  Earthquake  Insurance for any other  property under such Blanket
Policy,  Tenant shall maintain Flood and Earthquake  Coverage on the Master
Lease Property.

                (g)  All  Insurance,  except  for  Flood  and  Earthquake
Insurance  if the Property is not in Flood Zone or Seismic  Activity  Zone,
shall be in such form and shall be  issued  by such  responsible  insurance
companies  licensed  to do  business  in  the  State  of  Maryland  as  are
reasonably  approved by  Landlord.  Any  insurance  company  rated by Bests
Insurance Reports (or any successor  publication of comparable standing) as
"A-,  VIII" or  better  and by  Standard  &  Poor's  (or any  successor  of
comparable standing) as "A" or better (or the equivalent of such rating)

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(collectively, the "Standard Rating") shall be deemed a responsible company
and acceptable to Landlord.  Notwithstanding  the  foregoing,  in the event
that the rating of such  insurance  falls below the Standard  Rating during
the term of the policy of such  insurance,  Tenant shall not be required to
procure  replacement  coverage  until the  scheduled  expiration or earlier
termination  of such  policy;  provided,  however,  in no event  shall such
period exceed twelve (12) months.  Upon the Effective Date, and thereafter,
not less than five (5) days prior to the  expiration  dates of the expiring
policies  of  Insurance,  originals  of  replacement  policies  or  renewal
certificates,  as the case may be, bearing notations evidencing the payment
of premiums or  accompanied by other evidence  reasonably  satisfactory  to
Landlord  of each  payment,  shall  be  delivered  by  Tenant  to  Landlord
("Insurance  Notice").  If  Tenant  does  not  provide  Landlord  with  the
Insurance Notice or if Tenant lets any Insurance lapse, Landlord shall have
the right,  without providing any notice to Tenant, to procure  replacement
coverage  that is  effective  upon such  lapse and  Tenant  shall  promptly
reimburse Landlord for the reasonable cost thereof.

                  (h)  All  policies  of  Insurance  shall  name  Landlord,
Tenant,  and,  if  requested  by  Landlord in  writing,  any  Mortgagee  as
insureds,  as their  respective  interests  may  appear.  All  policies  of
Insurance other than the Liability Policy shall, if requested in writing by
Landlord,  name the  Mortgagee  as a loss  payee,  as the  interest of such
Mortgagee  may  appear,  but subject to the  provisions  of Section 15. Any
request of coverage as to a Mortgagee  shall set forth the name and address
of the Mortgagee.

                  (i) Tenant shall not violate or permit to be violated any
of the conditions,  provisions or requirements of any Insurance policy, and
Tenant shall  perform,  satisfy and comply with,  or cause to be performed,
satisfied and complied with, the conditions, provisions and requirements of
all Insurance  policies and the companies writing such policies so that, at
all  times,  the  Insurance  shall  be  provided  by  companies  reasonably
acceptable to Landlord, except as otherwise provided in Subsection 14(g).

                  (j) Each policy or certificate of Insurance shall contain
(i) an  agreement  by the insurer  that such policy  shall not be canceled,
modified or denied renewal  without at least thirty (30) days prior written
notice to  Landlord  and any  Mortgagee  named as an insured or loss payee,
except  that if the  reason  for  cancellation  or  denial  of  renewal  is
nonpayment of premiums, the notice will be at least ten (10) days, and (ii)
a waiver of subrogation by the insurer.

                  (k) If by  reason  of  changed  economic  conditions  the
Insurance  amounts  referred  to in  this  Lease  become  inadequate,  upon
Landlord's request, the limits shall be reasonably increased by Tenant from
time to time (but not more often than once every  twenty-four  (24) months)
to meet  the  changed  conditions,  but any  changes  in  limits  shall  be
consistent with what is customary for

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Comparable Buildings and Comparable Properties or for operations similar to
those conducted on the Master Lease Property.  Upon the reasonable  request
of  Landlord,  Tenant  shall  procure and obtain such types of insurance in
lieu of the current insurance then required under this Lease; provided that
such replacement coverage is of a substantially similar scope and nature as
the Insurance  then required  under this Lease and is the type of insurance
that is customary for Comparable Buildings and Comparable Properties or for
operations  similar  to  those  conducted  on the  Master  Lease  Property.
Notwithstanding  the  foregoing,  in the event  that  Landlord  makes  such
request  during  the  term of the  policy  of the  insurance  that is being
replaced,  Tenant  shall not be  required to procure  replacement  coverage
until the  scheduled  expiration  or earlier  termination  of such  policy;
provided, however, in no event shall such period exceed twelve (12) months.

                  (l)  Notwithstanding any provisions in this Section 14 or
elsewhere in this Lease to the  contrary,  any  deductible  to the All Risk
Policy shall be deemed an amount covered by Insurance and shall be promptly
paid by Tenant in the event of an Insurable Casualty.

         SECTION 15.       DAMAGE OR DESTRUCTION

                  (a) In case of damage  to or  destruction  of the  Master
Lease  Property or any part thereof by fire or other  casualty  ("Damage"),
Tenant will promptly give written notice thereof to Landlord. If the Damage
is caused by an Insurable  Casualty,  Tenant shall,  in accordance with the
provisions of this Section and all other provisions of this Lease,  restore
the same as nearly as possible to its condition  and character  immediately
prior to such  Damage,  subject to Tenant's  right to make  Alterations  in
substantial  conformity  with and subject to the  conditions  of Section 13
hereof, and in conformity with the plans and specifications  required to be
prepared pursuant to Section 13 and subject to any restrictions  imposed by
Applicable  Laws  ("Restoration"),  whether or not  insurance  proceeds are
sufficient to pay in full the cost of the work.  The  Restoration  shall be
commenced  within sixty (60) days after the loss is finally  adjusted  with
the insurer,  the plans,  specifications  and contract for the  Restoration
have been  approved by Landlord  under Section  15(b)(i) and (ii),  and all
necessary permits for the Restoration have been issued. Tenant shall pursue
such adjustment of the loss, approvals of Landlord, and issuance of permits
with  reasonable  diligence  after the  Damage.  The  Restoration  shall be
prosecuted and completed with reasonable  diligence after its commencement,
Unavoidable Delays excepted.  Landlord shall cooperate fully with Tenant in
order to obtain the largest possible  insurance  recovery and shall execute
any and all  consents  and other  instruments  and take all  other  actions
reasonably  necessary  to  accomplish  the same and to cause the  insurance
proceeds to be paid as provided in Subsection (c) below.


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                  (b) In the event that the cost of Restoration exceeds One
Hundred Seventy  Thousand Dollars  ($170,000),  Tenant agrees to furnish to
Landlord at least twenty (20) days before the
commencement of Restoration, the following:

                           (i) Complete plans and specifications for
Restoration  prepared  by a licensed  and  reputable  architect  reasonably
satisfactory to Landlord (the "Architect"),  which plans and specifications
shall meet with the  reasonable  approval of  Landlord,  together  with the
approval   thereof  by  all   governmental   authorities   then  exercising
jurisdiction  with regard to such work, and which plans and  specifications
shall be and become the sole and absolute property of Landlord in the event
that, for any reason, this Lease shall be terminated.

                           (ii)     A contract then customary in the trade with
(A) the Architect,  and (B) a reputable and responsible  general contractor
reasonably   approved  by  Landlord,   providing  for  the   completion  of
Restoration  in  accordance  with  said  plans  and  specifications,  which
contract shall meet with the reasonable approval of Landlord.

                           (iii) Assignment of the contract with the
Architect  and the general  contractor  so  furnished,  duly  executed  and
acknowledged by Tenant, the Architect and the general contractor,  by their
terms to be effective upon any termination of this Lease or upon Landlord's
re-entry upon the Master Lease Property  prior to the complete  performance
of such contracts.

                  (c) All insurance  proceeds  payable on account of Damage
shall be paid to Mortgagee  (provided  such  Mortgagee is an  Institutional
Mortgagee) or to a trustee  designated by Mortgagee  ("Insurance  Trustee")
and applied to the payment of the cost of  Restoration,  including the cost
of temporary  repairs or for the  protection  of the Master Lease  Property
pending  the   completion   of  permanent   work  pursuant  to  the  plans,
specifications and contracts (all of which temporary repairs, protection of
Master Lease  Property and permanent work shall be deemed to be part of the
Restoration). In the event of Damage in which the proceeds of insurance are
Five Hundred Thousand Dollars ($500,000.00) or less, such proceeds shall be
payable  directly to Tenant,  in trust,  to be applied to the  Restoration.
Such funds shall be used only for such purposes  until the  Restoration  is
completed and any excess  proceeds  shall be retained by Tenant for its own
account.  In the event of Damage in which the proceeds of insurance  exceed
Five  Hundred  Thousand  Dollars  ($500,000.00),  such  proceeds  shall  be
deposited  with  Mortgagee or with the  Insurance  Trustee in a bank in the
Washington  D.C.  metropolitan  area as  designated  by Landlord  and, upon
written  request of Tenant,  shall be paid out to Tenant  from time to time
(but no more  often  than once per  month) as  Restoration  progresses,  in
trust,  for the purposes of paying the cost of Restoration.  The receipt by
Landlord and its  Mortgagee of the following  are  conditions  precedent to
each payment of insurance proceeds by the Mortgagee or Insurance Trustee to
Tenant:

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                           (i)     A requisition ("Requisition") signed by
Tenant,  dated not more than 30 days prior to such request,  certifying the
following:

                                  (A)  that the sum then requested either has
been  paid by  Tenant  or is  justly  due to  contractors,  subcontractors,
materialmen,  engineers,  architects  or other  persons  who have  rendered
services or furnished  materials for the portion of the Restoration therein
specified, and giving a brief description of such services and material and
the  several  amounts  so paid or due to each of said  persons  in  respect
thereof,  and stating  that such  amounts  have not been the subject of any
previous  Requisition  and do not  exceed  the  value of the  services  and
materials described in the Requisition,  and stating, in reasonable detail,
the progress of the work in connection  with  Restoration up to the date of
the Requisition;

                                  (B)  that, to the best of Tenant's knowledge,
except  for the  amount  set forth in the  Requisition  and  except for any
amount  related to services or  materials  furnished  after the date of the
Requisition, there is no other amount then due for services or materials in
connection with Restoration  which, if unpaid,  might become the basis of a
mechanic's,  materialmen's,  or similar lien upon the Master Lease Property
or any part thereof; and

                                  (C)  that, to the best of Tenant's knowledge,
the materials,  fixtures and equipment for which payment is being requested
pursuant to this Section are substantially in accordance with the plans and
specifications approved by Landlord.

For the purposes of this Subsection 15(c)(i), (i) "Institutional Mortgagee"
shall mean Nomura Asset Capital  Corporation and its successors and assigns
or any federally insured savings bank,  federally insured  commercial bank,
trust company, life insurance company,  casualty insurance company, pension
fund, real estate investment trust, mortgage company, credit union, college
or university,  charitable  institution,  or government agency or fund with
tangible  net  worth  in  excess  of  Two  Hundred  Fifty  Million  Dollars
($250,000,000),  and (ii) "Tenant's  knowledge" shall mean the then current
knowledge of the General  Manager of  Corporate  Services of Tenant or such
other authorized representative of Tenant overseeing the Restoration.

                           (ii)    A certificate or report of a title insurance
company  reasonably  satisfactory to Landlord and such Mortgagee,  or other
evidence  reasonably  satisfactory to Landlord and such  Mortgagee,  to the
effect  that  there has not been filed  with  respect  to the Master  Lease
Property or any part thereof or upon Tenant's  leasehold  interest  therein
any  mechanic's,  materialman's  or other lien in respect of such  services
rendered or materials furnished which has not been discharged of record.

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                           (iii) A certificate from Tenant stating that, to
the best of Tenant's knowledge, no Event of Default then exists.

Simultaneously with receipt of the insurance proceeds, Tenant shall deliver
to Landlord and such  Mortgagee  acknowledgments  of payment and waivers of
lien from all vendors,  mechanics and laborers  receiving  payment,  to the
extent of the work performed through the date of the previous Requisition.

                  (d) If the insurance  proceeds shall be  insufficient  to
pay the entire cost of Restoration, Tenant will pay the deficiency.

                  (e) Upon  receipt by  Landlord or any such  Mortgagee  of
satisfactory  evidence of the character  required by  Subsection  (c) above
that  Restoration  has been  completed  and  paid  for in full  (including,
without  limitation,  a copy of the permanent or temporary  certificate  of
occupancy for the Main Building,  if a new  certificate is issued or if the
then existing certificate is modified, and a then current,  complete set of
"as built" plans for the Restoration,  if the cost of such plans is covered
by  Insurance)  and that there are no Events of Default then in  existence,
any balance of the insurance  proceeds at the time held by Mortgagee or the
Insurance  Trustee  shall be paid to and may be  retained by Tenant for its
own account.

                  (f) Notwithstanding the foregoing,  if at the time of any
Damage,  Tenant fails to maintain a credit  rating for  Tenant's  corporate
debt of at least BB as rated by an "Approved  Credit  Rating  Agency",  the
following provisions shall apply:

                           (i)  All references in Subsection 15(c) to "Five
Hundred Thousand  Dollars  ($500,000)"  shall be deemed  references to "One
Hundred Thousand Dollars ($100,000)";

                           (ii)   The   following   shall   be   additional
conditions precedent  to those set forth in  Subsection  15(c) in order for
Tenant to receive insurance proceeds held by the Mortgagee or Insurance Trustee:

                                    (A) A Certificate from the Architect
stating that the  materials,  fixtures  and  equipment  for which  payment is
being requested pursuant to this Section are substantially in accordance with
the plans and specifications approved by the Landlord.

                                    (B) Upon  occurrence of Damage,  Tenant
shall deposit with Mortgagee or the Insurance  Trustee any  deductible  under
the Insurance.  In  addition,  Tenant  shall  deposit  with the  Mortgagee  and
Insurance Trustee any excess cost of the  Restoration  over the  Insurance
Proceeds and Deductible held by Landlord at the time of final adjustment of
the loss or at the time of any Requisition.

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                                    (C) Ten percent (10%) of the cost of the
Restoration  shall be held back by Mortgagee or the Insurance Trustee until
Tenant has complied with all of the provisions of this Section 15.

For purposes of this Subsection  15(f), an "Approved  Credit Rating Agency"
shall mean Standard & Poor's,  Moody's or any other  nationally  recognized
rating agency.

                  (g)  If any  Damage  shall  occur,  then,  to the  extent
Landlord  is  compensated  by  the  Rent  Insurance   required  by  Section
14(a)(iv),  Base Rent shall  abate from the date of the  Damage,  until the
date the Restoration is completed,  to the extent that the Main Building is
rendered unusable by the Damage.

                  (h) Despite the foregoing, if (i) Damage in excess of TWO
MILLION FIVE HUNDRED THOUSAND AND NO/100 DOLLARS  ($2,500,000) or in excess
of an amount  equal to the  remaining  payments of Base Rent due under this
Lease, whichever is less, is caused by a casualty which is not an Insurable
Casualty,  or (ii) during the last two (2) Lease Years of the Term,  Damage
is caused by an  Insurable  Casualty  and the loss  amounts to  twenty-five
percent (25%) or more of the Replacement Value of the Main Building,  then,
in either  event,  Tenant shall have the right to  terminate  this Lease by
giving written  notice of  termination to Landlord  within ninety (90) days
after  the  occurrence  of such  Damage  provided  that the Rent  Insurance
required  by  Section  14(a)(iv)  is then in  effect.  In the event of such
termination,  the Term of this Lease shall expire and come to an end thirty
(30) days  after the day that the  notice is given  with the same force and
effect  as if that  day had  been the  Expiration  Date  and any  insurance
proceeds  payable  for the Damage  shall  exclusively  belong to  Landlord.
Thereafter,  neither  party  shall have any further  rights or  liabilities
under this Lease,  except with  respect to any  obligations  which arose or
accrued before the termination or with respect to any rights or liabilities
which expressly survive  termination under the terms of this Lease. As used
in this Lease  "Insurable  Casualty" means any casualty,  regardless of the
degree of the  Damage,  covered by  Insurance  which  Tenant is required to
maintain under Section 14, whether or not Tenant  maintains such insurance.
Notwithstanding any other provision contained in this Section, Tenant shall
not be entitled to terminate  this Lease (A) if the Damage is caused by (i)
any  fraudulent or dishonest act or acts  committed by the Tenant or any of
the Tenant's  employees with the manifest intent to (a) cause the Tenant to
sustain such loss and (b) obtain financial benefit for the Tenant, Tenant's
employee, or for any other person or organization intended by the Tenant or
the  Tenant's  employee  to receive  such  benefit  (other  than  salaries,
commissions,  fees, bonuses, promotions,  awards, profit sharing, pensions,
or other employee  benefits earned in the normal course of employment),  or
(ii)  the  risks of  contraband  or  illegal  trade,  or  (iii)  any of the
following:  (1) defective design or  specifications,  faulty  material,  or
faulty workmanship;  (2) mechanical breakdown;  (3) ordinary wear and tear,
gradual deterioration, insect, vermin, inherent vice and loss of use; (4)

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normal settling or shrinkage of walls, floors, or ceilings;  or (5) loss of
market,  business  interruption,  or extra  expense  loss due to delay with
respect to  property  in  transit;  or (B) in the case of clause (i) of the
first sentence of this Subsection 15(h), if Landlord provides the funds, in
excess of the applicable amount set forth in such clause (i),  necessary to
cause  Restoration of the Main Building,  in which event such funds will be
applied in the manner  provided in Subsection  15(c), as if such funds were
insurance proceeds.

                  (i) Notwithstanding any other provision contained in this
Section,  all  insurance  proceeds  payable  for loss or damage to Tenant's
Personal  Property shall be the exclusive  property of and be paid directly
to Tenant.

                  (j) Tenant hereby  releases  Landlord and Landlord hereby
releases  Tenant from any and all liability for any loss,  damage or injury
to person or  property  occurring  in,  on,  about or to the  Master  Lease
Property,  the Main  Building  Area or  personal  property  within the Main
Building Area, by reason of fire or other casualty,  to the extent proceeds
of Insurance are received for such loss, damage, or injury or to the extent
such proceeds  should have been  received  under  Insurance  required to be
carried by this  Lease.  Because the  provisions  of this  Subsection  will
preclude the assignment of any claim mentioned herein by way of subrogation
or otherwise to an insurance company or any other person, Tenant shall give
to each  insurance  company  which has issued to it one or more policies of
insurance, notice of the terms of the release contained in this Subsection,
and have such  insurance  policies  properly  endorsed,  if  necessary,  to
prevent the  invalidation  of insurance  coverages by reason of the release
contained in this Subsection.

                  SECTION 16.       INDEMNIFICATION

                  (a) Tenant  will  protect,  indemnify  and save  harmless
Landlord from and against all liabilities,  obligations,  claims,  damages,
penalties,   causes  of  action,  costs  and  expenses  (including  without
limitation,  reasonable  attorneys'  fees  and  expenses)  imposed  upon or
incurred by or asserted  against  Land lord by reason of (i) any  accident,
injury to or death of persons or loss of or damage to property occurring on
or about  the  Master  Lease  Property  or any part  thereof  caused by the
negligence  or  intentional  misconduct  of Tenant or its Agents;  (ii) any
failure on the part of Tenant to perform or comply with any of the terms of
this Lease; or (iii) performance of any labor or services or the furnishing
of any materials or other  property in respect of the Master Lease Property
or any part thereof at the  direction  of Tenant.  Tenant  hereby  releases
Landlord from any and all liability for the same.

                  (b) Landlord  will  protect,  indemnify and save harmless
Tenant from and  against all  liabilities,  obligations,  claims,  damages,
penalties,   causes  of  action,  costs  and  expenses  (including  without
limitation, reasonable attorneys' fees and

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expenses)  imposed upon or incurred by or asserted against Tenant by reason
of (i) any accident,  injury to or death of persons or loss of or damage to
property  occurring  on or about  the  Master  Lease  Property  or any part
thereof,  caused by the negligence or intentional misconduct of Landlord or
its  Agents;  (ii) any failure on the part of Landlord to perform or comply
with any of the terms of this Lease;  or (iii)  performance of any labor or
services or the furnishing of any materials or other property in respect of
the Master Lease Property or any part thereof at the direction of Landlord.
Landlord hereby releases Tenant from any and all liability for the same.

                  (c) The amount which any party (an "Indemnifying  Party")
is or may be required to pay to any other party (an "Indemnitee")  pursuant
to this  Section  16  shall  be  reduced  (including,  without  limitation,
retroactively)  by any  insurance  proceeds  (or the  amount  of  insurance
proceeds  that would have been  recovered  had  insurance  required by this
Lease been obtained) or other amounts actually recovered by or on behalf of
such  Indemnitee,  in reduction of the related loss. If an Indemnitee shall
have received payment (an "Indemnity  Payment") required by this Lease from
an  Indemnifying  Party  in  respect  of any loss  and  shall  subsequently
actually  receive  insurance  proceeds or other  amounts in respect to such
loss, then such Indemnitee shall pay to such Indemnifying Party a sum equal
to the amount of such insurance proceeds or other amounts actually received
(up to but not in  excess  of the  amount  of any  Indemnity  Payment  made
hereunder).  An insurer who would  otherwise  be obligated to pay any claim
shall not be relieved  of the  responsibility  with  respect  thereto,  or,
solely  by  virtue  of the  indemnification  provisions  hereof,  have  any
subrogation rights with respect thereto, it being expressly  understood and
agreed  no  insurer  or any  other  third  party  shall  be  entitled  to a
"windfall"  (i.e.,  a benefit  they would not be entitled to receive in the
absence of the indemnification provisions) by virtue of the indemnification
provisions hereof.

                  (d) Procedures for  indemnification of Third Party Claims
shall be as follows:

                           (i)      If an Indemnitee shall receive notice or
otherwise  learn  of  the  assertion  by  a  person   (including,   without
limitation, any governmental entity) who is not a party to this Lease (or a
subsidiary an affiliate of either party) of a claim or of the  commencement
by any such person of any action (a "Third  Party  Claim")  with respect to
which an  Indemnifying  Party may be obligated  to provide  indemnification
pursuant  to this  Section  16 or any other  Section  of this  Lease,  such
Indemnitee  shall  give such  Indemnifying  Party  written  notice  thereof
promptly after becoming aware of such Third Party Claim;  provided that the
failure of any  Indemnitee to give notice as provided in this Section 16(d)
shall not  relieve the  Indemnifying  Party of its  obligations  hereunder,
except to the extent that such Indemnifying Party is actually prejudiced by
such failure to give

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notice.  Such notice shall describe the Third Party Claim in
reasonable detail.

                           (ii) An  Indemnifying  Party may elect to defend
or to seek to settle or compromise,  at such Indemnifying  Party's own expense
and such  Indemnifying  Party's  own  counsel,  any Third Party  Claim,  as
provided hereafter. Within thirty (30) days after receipt of notice from an
Indemnitee in accordance with Subsection 16(d)(i) (or sooner, if the nature
of such Third Party Claim so requires), the Indemnifying Party shall notify
the Indemnitee of its election whether the  Indemnifying  Party will assume
responsibility  for defending such Third Party Claim.  After notice from an
Indemnifying  Party to an  Indemnitee of its election to assume the defense
of a Third Party Claim, such Indemnifying Party shall not be liable to such
Indemnitee  under this Section 16 for any legal or other  expenses  (except
expenses  approved  in  advance  by the  Indemnifying  Party)  subsequently
incurred  by such  Indemnitee  in  connection  with  the  defense  thereof;
provided that if the defendants  with respect to any such Third Party Claim
include both the Indemnifying  Party and one or more Indemnitees and in any
Indemnitee's reasonable judgment a conflict of interest between one or more
of such Indemnitees and such  Indemnifying  Party exists in respect to such
claim,  such Indemnitees shall have the right to employ separate counsel to
represent  such  Indemnitees  and in that  event  the  reasonable  fees and
expenses of such separate  counsel (but not more than one separate  counsel
reasonably  satisfactory to the  Indemnifying  Party) shall be paid by such
Indemnifying   Party.  If  an  Indemnifying  Party  elects  not  to  assume
responsibility  for  defending a Third Party  Claim,  or fails to notify an
Indemnitee of its election as provided in this Subsection  16(d)(ii),  such
Indemnitee  may defend  or,  subject to the  remainder  of this  Subsection
16(d)(ii),  seek to  compromise  or settle such Third  Party Claim  without
prejudice  to  such  Indemnitee's  rights,  if  any,  to  continue  to seek
indemnification  hereunder.   Notwithstanding  the  foregoing,  neither  an
Indemnifying  Party nor an Indemnitee  may settle or  compromise  any claim
over the  objection  of the  other;  provided,  however,  that  consent  to
settlement or  compromise  shall not be  unreasonably  withheld or delayed.
Neither an Indemnifying  Party nor an Indemnitee  shall consent to entry of
any  judgment or enter into any  settlement  of any Third Party Claim which
does not include as an unconditional  term thereof the giving by a claimant
or plaintiff to such Indemnitee,  in the case of a consent or settlement by
an  Indemnifying  Party,  or to the  Indemnifying  Party,  in the case of a
consent or  settlement  by an  Indemnitee,  of a written  release  from all
liability in respect to such Third Party Claim.

                           (iii) If an Indemnifying Party chooses to defend
or to seek to  compromise  or settle any Third  Party  Claim,  the  related
Indemnitee shall make reasonably  available to such Indemnifying  Party any
personnel or any books,  records or other  documents  within its control or
which it otherwise has the ability to make  available that are necessary or
appropriate for such defense, settlement or compromise of such Third Party

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Claims,   subject   to  the   establishment   of   reasonably   appropriate
confidentiality  arrangements  and  arrangements to preserve any applicable
privilege (including, the attorney-client privilege) and shall cooperate in
such defense, compromise or settlement. If an Indemnifying Party chooses to
defend or to seek to  compromise  or  settle  any Third  Party  Claim,  the
related  Indemnitee shall be entitled to attend and participate in any such
proceeding, discussion or negotiation at its own expense.

                           (iv)  Notwithstanding anything else in this
Section 16 to the contrary,  if an Indemnifying  Party notifies the related
Indemnitee  in writing  of such  Indemnifying  Party's  desire to settle or
compromise  a Third  Party  Claim on the  basis  set  forth in such  notice
(provided that such settlement or compromise  includes as an  unconditional
term thereof the giving by the  claimant or plaintiff of a written  release
of the  Indemnitee  from all  liability  in  respect  thereof  and does not
include any  non-monetary  remedy) and provides the  Indemnitee a copy of a
written  proposal of the applicable  claimant to settle on such terms,  and
the Indemnitee  notifies the Indemnifying  Party in writing within ten (10)
business  days of such notice that such  Indemnitee  declines to accept any
such settlement or compromise, such Indemnitee may continue to contest such
Third Party Claim, free of any participation by such Indemnifying Party, at
such  Indemnitee's  sole  expense.  In such event,  the  obligation of such
Indemnifying  Party to such  Indemnitee  with  respect to such Third  Party
Claim shall be equal to (i) the costs and expenses of such Indemnitee prior
to the date such  Indemnifying  Party notifies such Indemnitee of the offer
to settle  or  compromise  (to the  extent  such  costs  and  expenses  are
otherwise  indemnifiable  hereunder) plus (ii) the lesser of (A) the amount
of any offer of settlement or compromise which such Indemnitee  declined to
accept and (B) the actual out-of-pocket amount such Indemnitee is obligated
to pay subsequent to such date as a result of such Indemnitee's  continuing
to defend such Third Party Claim (including attorneys fees and expenses).

                          (v)   Any claim on account of a loss which does not
result from a Third Party Claim shall be asserted by written  notice  given
by the  Indemnitee to the related  Indemnifying  Party.  Such  Indemnifying
Party  shall  have a period of 30 days  after the  receipt  of such  notice
within  which to  respond  thereto.  If such  Indemnifying  Party  does not
respond within such thirty (30) day period,  such Indemnifying  Party shall
be deemed to have refused to accept responsibility to make payment. If such
Indemnifying  Party does not respond  within such thirty (30) day period or
rejects such claim in whole or in part,  such  Indemnitee  shall follow the
dispute resolution procedures set forth in Subsection 11(c).

                          (vi)   In addition to any adjustments required
pursuant to Subsection  16(c), if the amount of any loss shall, at any time
subsequent to the payment  required by this Lease,  be reduced by recovery,
settlement or otherwise,  the amount of such  reduction,  less any expenses
incurred in connection therewith,

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shall promptly be repaid by the Indemnitee to the Indemnifying Party.

                           (vii)  In the event of payment by an Indemnifying
Party to any  Indemnitee  in  connection  with any Third Party Claim,  such
Indemnifying  Party shall be subrogated to and shall stand in the place and
the place of such Indemnitee as to any events or  circumstances  in respect
of which such Indemnitee may have any right or claim relating to such Third
Party Claim  against any claimant or plaintiff  asserting  such Third Party
Claim or against any other person.  Such  Indemnitee  shall  cooperate with
such Indemnifying Party in a reasonable manner, and at the cost and expense
of such Indemnifying Party, in prosecuting any subrogated right or claim.

                           (vii) If any indemnity payment required to be made
hereunder is denominated  in a currency  other than United States  dollars,
such payment shall be made in United States  dollars and the amount thereof
shall be  computed  using  the  foreign  exchange  rate  for such  currency
determined  as of the date that  notice of the claim with  respect to which
such indemnity payment is made or given by, or on behalf of, the Indemnitee
to the Indemnifying Party.

                  (e) The provisions of this Section 16 shall survive any
termination of this Lease.

                  SECTION 17.       CONDEMNATION

                  (a) (i) If any part of the Master Lease Property is taken
or  condemned  for a  public  or  quasi-public  use  (a  sale  in  lieu  of
condemnation to be deemed a taking or condemnation) ("Taken" or a "Taking",
as the context  shall  require),  this Lease  shall,  as to the part Taken,
terminate as of the date title shall vest in the  condemnor and continue in
full force as to the remainder. In the event of such a partial Taking, Rent
shall be equitably  adjusted by Landlord and Tenant taking into account the
portion of the Master Lease Property so Taken;  provided,  that there shall
be no  adjustment  in Base Rent  unless,  and only to the  extent  that,  a
portion of the Main Building is Taken.  With respect to any other  portions
of the Master Lease Property  Taken,  adjustment  shall be made only to the
Additional  Rent applicable to and the obligation to Care for such portion.
Tenant, at its cost and expense, shall proceed with Restoration, subject to
Unavoidable  Delays,  of the remaining portion of the Master Lease Property
to  a  complete   architectural   unit,  to  the  extent   practicable  and
economically  feasible  and to the  extent  the net  condemnation  award is
sufficient to pay in full the cost of such  Restoration.  Such  Restoration
shall be performed  in the same manner and pursuant to the same  conditions
as set forth in Section 15 hereof with respect to  Restoration  as a result
of  Damage.  If the  parties  cannot  agree  upon such Rent  adjustment  or
Restoration  requirements,   such  dispute  shall  be  decided  by  binding
arbitration comparable to that provided for in Section 11(c).

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                          (ii) Tenant waives all claims against Landlord and
any  Mortgagee by reason of any partial  Taking,  and Tenant  covenants and
agrees that Tenant will make no claim against the  condemning  authority by
reason of the  partial  Taking,  except for  damages  payable for injury to
Personal Property or any Alterations that Tenant is entitled to remove upon
the expiration of this Lease, for loss of use of the Main Building Area, or
for relocation  expenses;  provided,  however,  that Tenant's claims do not
reduce Landlord's award for its fee interest subject to Tenant's  leasehold
interest.  In such event, Tenant shall be entitled to receive such amounts.
Landlord  or any  Mortgagee  having a right  thereto  shall be  entitled to
receive any and all awards paid by the  condemning  authority in connection
with such partial Taking, provided that such condemnation award received by
Landlord or such Mortgagee,  less the reasonable costs incurred by Landlord
and such Mortgagee in connection with the collection of such award shall be
applied to the cost of such Restoration,  subject to the same conditions to
release set forth in Section 15 hereof.  Any balance of the award remaining
after completion of such Restoration and not used for such Restoration, may
be retained by Landlord or such Mortgagee.

                          (iii) Notwithstanding the foregoing provisions of
this Subsection (a), in the case of partial Taking of the Main Building, if
Landlord or Tenant shall reasonably determine that the remaining portion of
the  Main  Building  cannot  practicably  be  so  restored  to  a  complete
architectural unit or that such Restoration is not economically feasible or
that after the Restoration, the remainder of the Main Building would not be
suitable for the uses permitted  hereunder,  then either Landlord or Tenant
may  terminate  this  Lease by notice to the other  party,  and,  upon such
termination,   Tenant  and  Landlord  shall  have  no  further  obligations
hereunder,  except with respect to any  obligations  which arose or accrued
before the  termination of this Lease or to the extent  obligations  are to
survive the termination of this Lease as otherwise  provided in this Lease.
Any dispute as to the right of Landlord or Tenant to  terminate  this Lease
under  this  Subsection   (iii)  shall  be  determined  by  arbitration  in
accordance  with  Section  11(c).  In the  event of a Taking  that does not
result in the  termination  of this  Lease,  but results in a Taking of any
portion of the Main Building  Area,  Landlord  shall provide  Tenant with a
portion of the Unimproved Area for use for replacement  parking adjacent to
the  remaining  Main  Building  Area and access and  utilities  to the Main
Building  to the extent  such items are  affected  by the  Taking.  Nothing
herein shall be construed to require Landlord to incur any material expense
in connection therewith.

                  (b) In the event of a total  Taking of the Main  Building
Area,  this Lease  shall  terminate  as of the date title shall vest in the
condemnor  and,  upon such  termination,  Landlord and Tenant shall have no
further  obligations  hereunder,  except with respect to any breaches which
occurred before the termination of this Lease or to the extent  obligations
are to survive the termination of this Lease as otherwise provided in

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this Lease.  Landlord  shall be entitled to receive any and all awards paid
by the condemning  authority in connection with such Taking,  except to the
extent Tenant is entitled to recovery under Subsection 17(a)(ii).

                  SECTION 18.       LIENS

                  If,  because of any act or  omission  of Tenant or anyone
claiming by,  through,  or under Tenant,  any mechanic's lien or other lien
shall be filed against the Master Lease Property or any portion thereof, or
against  other  property of Landlord,  whether or not such lien is valid or
enforceable as such, Tenant shall, at its own expense, cause the same to be
discharged of record within a reasonable time, not to exceed 30 days, after
the date of filing  thereof,  and shall also defend and indemnify  Landlord
and any Mortgagee  and hold them harmless from any and all claims,  losses,
damages, judgments,  settlements,  costs and expenses, including reasonable
attorneys' fees,  resulting therefrom or incurred in connection  therewith.
Tenant shall not mortgage,  pledge,  hypothecate  or assign as security its
interest in the Master Lease Property or under this Lease.

                  SECTION 19.       EXISTING SPACE LEASES; ASSIGNMENT AND
                                            SUBLETTING

                  (a) On the Effective  Date,  the Main Building is subject
to those certain leases listed in Exhibit G attached hereto and made a part
hereof (the "Existing Space Leases"), which were entered into by Tenant, as
lessor thereunder, prior to closing under the Sales Agreement. Landlord has
not  assumed any of Tenant's  obligations  thereunder.  For so long as this
Lease  remains in  effect,  Tenant  covenants  and  agrees to  continue  to
discharge all of the lessor's  obligations under the Existing Space Leases,
whether  accrued  or  accruing  before or during  the  Term.  Tenant  shall
indemnify,  defend,  and hold harmless  Landlord  against any obligation of
Landlord  under the Existing  Space Leases  arising or accruing  during the
Term,  except to the extent Tenant is unable to perform such obligations as
a result of Landlord's breach of its obligations  under this Lease.  During
the Term, Tenant shall have the right to (i) collect and retain for its own
account  (subject to Subsection (c) below) all rents and other payments due
from tenants under Existing Space Leases  ("Existing  Tenants"),  (ii) hold
and apply any security  deposits of Existing Tenants in accordance with the
Existing Space Leases  (provided,  however,  that Tenant shall deliver such
security  deposits to Landlord at the expiration or earlier  termination of
this Lease to the extent such  security  deposits  have not been applied by
Tenant  pursuant to the applicable  Existing Space Lease or returned to the
applicable  Existing Tenant, and the term of the applicable  Existing Space
Lease extends beyond the Term),  and (iii)  terminate,  modify or otherwise
deal with the  Existing  Space  Leases as Tenant,  in its sole  discretion,
deems appropriate;  provided,  however,  (A) such right shall automatically
end upon the  termination  of this  Lease for any  reason,  (B) none of the
Existing Space Leases shall be modified to provide for a term

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which  extends  beyond the Term,  unless  Landlord  gives its prior written
consent to such extended term,  which consent may be granted or withheld in
Landlord's  sole  discretion,  (C) each  modification  of an Existing Space
Lease shall be subject and  subordinate to this Lease,  and in the event of
the expiration or termination of this Lease, Landlord shall not be required
to recognize such modification  without its express written agreement to be
bound by same, which may be given or not in Landlord's sole discretion, and
(D) Tenant  shall  promptly  provide to  Landlord  copies of all  documents
terminating or modifying any Existing Space Lease.

                  (b)  Tenant may  assign  its  interest  in this Lease (an
"Assignment")  or  sublet  all  or any  portion  of the  Main  Building  (a
"Sublease"), without the consent of Landlord. The term of any such Sublease
shall not exceed the Term,  unless Landlord gives its prior written consent
to such  extended  term,  which  consent  may be  granted  or  withheld  in
Landlord's  sole  discretion.  In the event of any  Assignment or Sublease,
Tenant shall  nevertheless at all times remain fully responsible and liable
for the  payment  of Rent  and the  performance  and  observance  of all of
Tenant's other obligations under this Lease. Each Sublease shall be subject
and subordinate to this Lease. If requested by Tenant, Landlord shall enter
into  a   nondisturbance   agreement   with  respect  to  any  Sublease  on
substantially  the  same  terms  as are  contained  in  the  nondisturbance
agreement  attached  hereto as Exhibit H (the  "Landlord  Approved  SNDA"),
provided  that (i) the Sublease does not, in any material  respect,  impose
greater  obligations  on the  sublandlord  or grant  greater  rights to the
subtenant  than those  existing as of the Effective Date under the Existing
Space  Leases,  (ii) term of the  Sublease  does not  extend  past the Term
(unless  expressly  approved by Landlord as provided above),  and (iii) the
Sublease (y) is an arms-length transaction and such subtenant was obtained,
and the economic  terms of such Sublease were  negotiated by, a third party
leasing  agent using  marketing  efforts  customarily  used for  Comparable
Properties,  or (z) requires the subtenant to pay basic rent at Fair Market
Sublease  Rent and a pro rata share of  increases  in  operating  expenses,
taxes and insurance (a "Non-Broker Sublease").  Landlord agrees at any time
hereafter, upon ten (10) business days prior written notice, to execute and
deliver, and cause its Mortgagee to recognize,  the Landlord Approved SNDA,
provided the Landlord  Approved  SNDA has been duly  executed by Tenant and
such  subtenant.  Promptly upon  entering into any  Assignment or Sublease,
Tenant shall provide  Landlord with copies of all documents  effecting such
Assignment or Sublease.

                  (c) In the event of a Non-Broker  Sublease,  Landlord and
Tenant shall attempt in good faith to agree as to the Fair Market  Sublease
Rent,  and if Landlord  and Tenant  fail to  promptly  agree as to the Fair
Market  Sublease Rent (the "Sublease  Arbitration  Deadline"),  Fair Market
Sublease Rent shall be determined as follows:

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                           (i)     Fair Market Sublease Rent shall be the rent
which would be asked of subtenants as of the anticipated  date of execution
of the Sublease for space  comparable  to the subject space of the Sublease
in the  Germantown/Clarksburg  areas of Montgomery County, Maryland, taking
into  account  the term of the  Sublease,  the size of the  premises  being
subleased and the value of brokerage commissions, rental abatements, rental
credits,  and tenant  allowances,  if any, being offered or paid under such
subleases.

                           (ii)  Landlord and Tenant shall use the same
methodology of the arbitration proceedings described in
Subsections 28(d)(ii) and (iii).

                  (d) As a part of  Additional  Rent,  Tenant  shall pay to
Landlord  one-half  of any Profit  derived  from any renewal of an Existing
Lease (a "Lease  Renewal") or from any  Assignment  or Sublease  during the
Term. As to each Lease Renewal,  Assignment,  and Sublease,  "Profit" shall
mean the excess,  if any, of the following:  the gross amount  collected by
Tenant under or with respect to the Lease Renewal,  Assignment, or Sublease
over a specific period of time (the "Measuring Period"),  less (i) the Base
Rent paid by Tenant to  Landlord  over the  Measuring  Period  for the same
space as is the subject of the Lease Renewal,  Assignment, or Sublease (the
"Subject Space"), (ii) all other amounts paid by Tenant with respect to the
Measuring  Period and relating to the Master Lease  Property as required by
this Lease,  pro-rated  based upon the rentable  area of the Subject  Space
compared to the rentable area of the Main Building,  (iii) a management fee
to Tenant  equal to three  percent  (3%) of the amount  collected by Tenant
under or with respect to the Lease  Renewal,  Assignment,  or Sublease over
the Measuring  Period,  (iv) all  reasonable  costs of  collection  paid by
Tenant to collect the sums payable under the Lease Renewal,  Assignment, or
Sublease,  and (v)  reasonable  and customary  brokerage  fees, the cost of
tenant improvements, reasonable attorneys' fees and all other out of pocket
costs paid by Tenant to third parties in connection with the Lease Renewal,
Assignment,  or Sublease. Tenant shall provide to Landlord on or before the
sixtieth  (60th) day following  each Lease Year in which Profit is received
by Tenant a calculation and payment of Profit for the preceding Lease Year.
The  calculation  shall  be  certified  by  Tenant  as being  accurate  and
complete,  to the best of its knowledge,  along with such  information  and
materials (including, but not limited to, copies of invoices,  calculations
and  allocations) in support thereof,  as Landlord may reasonably  request.
Despite  the  foregoing,  no  calculation  or  payment  of Profit  shall be
required  with respect to any  Assignment  or Sublease to a  subsidiary  of
Tenant or arising from a sale of any division or  subsidiary  of Tenant,  a
sale of all or substantially  all of the assets or capital stock of Tenant,
or any merger or consolidation of Tenant.

                  (e) If there is an Event of  Default,  in addition to any
other  remedies  provided  by this  Lease  or by law or in  equity,  at its
option, Landlord may collect directly from any Existing

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Tenant, Assignee or lessee under a Sublease ("Subtenant") all rent becoming
due to Tenant by reason of the  applicable  Existing  Lease,  Assignment or
Sublease. Any collection by Landlord from the Existing Tenant,  Assignee or
Subtenant  shall not be  construed  to  constitute a novation or release of
Tenant from the further  performance of its obligations under this Lease or
an acceptance of the terms of such Existing Lease, Assignment or Sublease.

                  (f) Any amounts collected by Landlord pursuant to Section
19(e) or otherwise from an Existing Tenant, Assignee or Subtenant which are
applicable to any period  preceding the Expiration Date (had this Lease run
its full Initial Term as may have been extended),  less Landlord's share of
any Profit  attributable  to such  amounts and less  Landlord's  reasonable
costs of  collection,  shall be applied by  Landlord  to the  reduction  of
Tenant's remaining liability, if any, under this Lease.

                  SECTION 20.       SUBORDINATION OR SUPERIORITY OF LEASE

                  (a) Except as  otherwise  provided in this  Section,  the
rights  and  interest  of Tenant  under this  Lease  shall be  subject  and
subordinate  to any  mortgages  that may be placed  upon the  Master  Lease
Property  and to any and all  advances  to be made  thereunder,  and to the
interest thereon, and all renewals, replacements,  extensions, bifurcations
and splits thereof,  if the Mortgagee named in said mortgage shall elect to
subject and  subordinate the rights and interest of Tenant under this Lease
to the lien of its mortgage. Any Mortgagee may elect to give the rights and
interest of Tenant under this Lease priority over the lien of its mortgage.
In the  event  of  either  such  election  and  upon  notification  by such
Mortgagee to Tenant to that effect, the rights and interest of Tenant under
this Lease shall be deemed to be subordinate  to, or to have priority over,
as the case may be, the lien of said mortgage,  whether this Lease is dated
prior to or  subsequent  to the date of said  mortgage  without any further
action  required by Landlord or  Mortgagee;  provided,  however,  that as a
condition  precedent to any subordination of this Lease,  Landlord delivers
in advance a  non-disturbance  agreement  duly  executed by  Mortgagee  and
Landlord. The non-disturbance  agreement shall be substantially in the form
attached  to and  made a part of  this  Lease  as  Exhibit  I (the  "Tenant
Approved  SNDA") or in a  commercially  reasonable  form and subject to the
approval of Tenant, not to be unreasonably  withheld.  Tenant agrees at any
time  hereafter,  upon ten (10)  business  days prior  written  notice,  to
execute and deliver the Tenant Approved SNDA.

                  (b)  Nothing  contained  in this  Lease  shall  limit  or
curtail  Landlord's right to sell,  mortgage or otherwise  transfer its fee
interest in the Master Lease Property, or affect Landlord's right to assign
the Rent payable  under this Lease either as  collateral  security  under a
mortgage or  otherwise.  Any such sale,  mortgage,  transfer or  assignment
shall be binding on Tenant but shall be subject to this Lease.



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                  SECTION 21.       DEFAULTS AND REMEDIES

                  (a) The  occurrence  of any one or more of the  following
events shall be a default and breach of this Lease by Tenant (collectively,
"Events of Default"):

                           (i)      Tenant shall fail to pay any installment of
Rent when the same shall be due and payable  and fail to cure such  default
within  nine  (9)  days  after  receiving   written  notice  from  Landlord
specifying  the default.  For the purposes of this  Subparagraph  21(a)(i),
Tenant  agrees notice by Mortgagee,  or Landlord's  loan service  provider,
given  according  to the terms of Section  26,  shall be deemed  sufficient
notice.

                           (ii)     Tenant shall fail to perform or observe any
other term,  condition,  covenant or obligation required to be performed or
observed  by it under  this  Lease for a period of thirty  (30) days  after
written notice from Landlord  specifying such default;  provided,  however,
that if the term,  condition,  covenant or  obligation  to be  performed by
Tenant is of such  nature  that the same  cannot  reasonably  be  performed
within such thirty (30) day period,  such  default  shall be deemed to have
been cured if Tenant commences such performance  within the thirty (30) day
period and thereafter diligently undertakes to complete the cure and in all
events cures the default within one hundred twenty (120) days of Landlord's
notice, subject to extension for Unavoidable Delays.

                           (iii) An Event of Default, as defined therein,
shall  occur  under  that  certain  lease  agreement,  dated  of even  date
herewith,  between  Landlord and Tenant with  respect to the  Installations
Premises (the "Facilities Lease").

                           (iv)  Termination or rejection of this Lease
pursuant to Section 22.

                           (v)   Assumption or assignment of this Lease, under
the  conditions  referred  to in Section  22,  unless the  requirements  of
Section 22 applicable to such assumption or assignment are satisfied.

                  (b) Upon the occurrence of any Event of Default, Landlord
shall have the following rights and remedies,  in addition to those allowed
by law or equity,  any one or more of which may be  exercised  concurrently
and without further notice to or demand upon Tenant:

                           (i)   Landlord may re-enter the Master Lease
Property  and cure any  default  of Tenant,  in which  event  Tenant  shall
reimburse Landlord as Additional Rent for any reasonable costs and expenses
which  Landlord may incur to cure such default;  and Landlord  shall not be
liable to Tenant for any loss or damage  which Tenant may sustain by reason
of Landlord's action, except loss or damage caused by Landlord's negligence
or intentional misconduct.

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                           (ii)   Landlord may terminate this Lease, in which
event:  (A) Tenant shall not  thereafter  be entitled to  possession of the
Master Lease Property and Tenant shall immediately thereafter surrender, or
cause to be  surrendered,  the  Master  Lease  Property  to  Landlord;  (B)
Landlord may re-enter the Master Lease  Property and  dispossess  Tenant by
summary  proceedings,  ejectment or other legal  process and may remove its
effects,  without prejudice to any other remedy which Landlord may have for
possession or  arrearages  in Rent;  and (C) Tenant shall be liable for all
loss or damage which Landlord may sustain by reason of such termination and
re-entry;  and  Landlord  may re-let  all or any part of the  Master  Lease
Property  for a  term  different  from  that  which  would  otherwise  have
constituted  the  balance  of the  Term  and  for  Rent  and on  terms  and
conditions different from those contained herein, whereupon Tenant shall be
obligated  to pay to  Landlord  the  deficiency,  if any,  between the Rent
provided  for  herein  and  that  provided  for in  any  lease  covering  a
subsequent  re-letting of the Master Lease  Property,  for the period which
would otherwise have constituted the balance of the Term, together with all
of Landlord's  reasonable  costs and expenses of preparing the Master Lease
Property for re-letting, including all repairs, tenant finish improvements,
brokers' and  attorneys'  fees,  and all loss or damage which  Landlord may
sustain by reason of such  re-letting,  it being  expressly  understood and
agreed that the liabilities and remedies  specified above shall survive the
termination of this Lease. Landlord shall make diligent efforts to mitigate
its damages in the event of an Event of Default.

                           (iii) (A) Notwithstanding the termination of this
Lease,  Landlord  may declare all Base Rent which would have been due under
this Lease for the balance of the Term to be immedi  ately due and payable.
In that  event,  Tenant  shall be  obligated  to pay an amount in cash that
would be necessary to purchase U.S.  Obligations in such amounts and having
such  maturities  that the principal and interest of such U.S.  Obligations
would be  sufficient  to provide funds as close as possible but in no event
less or later  than the  payments  due under this Lease as Base Rent as and
when such  payments  would be due if no  acceleration  of the Base Rent had
occurred (the "Accelerated  Payment").  U.S. Obligations are obligations or
securities not subject to prepayment,  call or early  redemption  which are
direct obligations of, or obligations fully guaranteed as to timely payment
by, the United States of America or any agency or instrumentality  thereof,
the  obligations  of which are  backed by the full  faith and credit of the
United States of America.

                           (B) Upon receipt of the Accelerated Payment,
Landlord  shall use  commercially  reasonable  efforts  to lease the vacant
areas of the Main  Building  at the then  currently  existing  fair  market
rental rate for Comparable  Buildings.  From and after the Event of Default
all rent and other payments, except for security deposits,  collected under
leases entered into after the Event of Default ("Post Default  Leases") and
under any Existing  Space  Leases,  Subleases,  or occupancy or  concession
agreements  in  effect  as of the  Event of  Default  shall be  placed in a
separate

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escrow  account  (the  "Escrow  Account")  held  by a  mutually  acceptable
escrowee (the "Escrowee").  Also, any refunds of Impositions paid by Tenant
and received by Landlord shall be placed in the Escrow Account.  The Escrow
Account shall be interest  bearing and earn at least a money market rate of
interest.  All interest  earned shall become part of the escrow fund and be
treated in the same manner as the principal in the Escrow Account. The Post
Default Leases and all Existing Space Leases,  Subleases, and occupancy and
concession agreements in effect as of the Event of Default are collectively
referred to as the "Mitigation  Leases".  The funds contained in the Escrow
Account shall be disbursed in the  following  manner and with the following
priority:  (i) all direct and  reasonable  operating  expenses  ("Operating
Expenses")  paid by Landlord  relating to the Master Lease Property  during
the "Default  Measuring  Period" (defined below) shall be paid to Landlord,
(ii) a management  fee equal to three percent (3%) of the amount  collected
by Landlord from the Mitigation  Leases during the Default Measuring Period
shall  be paid to  Landlord,  (iii)  all  direct  and  reasonable  costs of
collection  paid  by  Landlord  to  collect  the  sums  payable  under  the
Mitigation Leases shall be paid to Landlord,  (iv) reasonable and customary
brokerage  fees,  the  reasonable  cost  of  designing,   constructing  and
installing tenant  improvements,  reasonable  attorneys' fees and all other
reasonable  out of  pocket  costs  paid  by  Landlord  during  the  Default
Measuring Period to third parties in connection with the Mitigation  Leases
(including  the fees of the Escrowee and the Escrow  Account) shall be paid
to  Landlord,  (v) Tenant  shall be paid up to the amount  that  Tenant was
scheduled to pay as Base Rent during the Default Measuring Period, and (vi)
the remainder  shall be shared  equally by Landlord and Tenant.  As used in
this Section,  the term "Default Measuring Period" shall mean (1) as to the
payments  contemplated in (i) through (iv) above,  each consecutive one (1)
month period after the  establishment  of the Escrow Account until the date
the Term would have  expired but for the early  termination  of this Lease,
and  (2) as to the  payments  contemplated  in (v)  and  (vi)  above,  each
consecutive  three (3) month period after the  establishment  of the Escrow
Account  until  the date the Term  would  have  expired  but for the  early
termination of this Lease.  The first Default  Measuring  Period,  however,
shall also  include the period from the date of the Event of Default to the
date the Escrow Account was established.  Escrowee shall make disbursements
to the parties in the priority  described  above on or about the  fifteenth
(15th) day after the end of each Default Measuring Period.  Within ten (10)
days  after  the end of  each  Default  Measuring  Period  relating  to the
payments  contemplated in (i) through (iv) above, Landlord shall furnish to
Escrowee and Tenant a written  statement setting forth in reasonable detail
all amounts paid into the Escrow Account and all amounts for which Landlord
is claiming  payment  with  respect to the  immediately  preceding  Default
Measuring  Period.  The  statement  shall be certified by Landlord as being
accurate  and shall be  accompanied  by  invoices  and other  documentation
reasonably  evidencing  the amounts  claimed for  payment.  Escrowee  shall
withhold from the payments made under (v) and (vi) above one-fourth of the

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reasonably  estimated  real estate taxes and Insurance  premiums  which are
next due with respect to the Master Lease Property, less the amounts of any
real estate taxes or  Insurance  premiums  required to be directly  paid by
tenants under the  Mitigation  Leases (the "Tax and Insurance  Holdbacks").
Escrowee shall release Tax and Insurance  Holdbacks to Landlord when and to
the extent that real estate  taxes and  Insurance  premiums  are payable by
Landlord  with  respect to the Master Lease  Property.  At the time of each
such  disbursement to Landlord,  Escrowee shall also disburse to Tenant the
amount,  if any, by which the Tax and Insurance  Holdbacks held by Escrowee
exceed the tax bill or Insurance  premiums paid with such Tax and Insurance
Holdbacks. Although the last Default Measuring Period shall end on the date
the Term would have  expired but for the early  termination  of this Lease,
any amounts  collected by Landlord under the  Mitigation  Leases after that
date and attributable to any period which occurred prior to that date shall
be paid  directly  by  Landlord  to Tenant.  No party shall be paid for any
amount  described  in this  Subsection  (B) to the  extent  such  party was
otherwise  reimbursed  for  such  amount,  including,  without  limitation,
previous  payment  by the  Escrowee  or  previous  reimbursement  under the
Mitigation Leases. For the purposes of this Section,  "Operating  Expenses"
includes the amortized cost of capital  improvements  properly allocable to
the Default  Measuring Period but excludes (1) debt service and other costs
of Landlord's financing, (2) capital expenditures (except for the amortized
portion properly allocable to the Default Measuring Period), (3) management
fees, (4) overhead, (5) depreciation, (6) accountants' fees, (7) any losses
or expenses covered by Insurance,  whether or not such Insurance is in fact
maintained,  or  compensable  by  condemnation  proceeds,  (8)  any  amount
incurred by reason of the negligence or intentional  misconduct of Landlord
or its  Agents,  (9)  fines or  penalties,  and (10)  any  amounts  paid by
specific  tenants.  Any refunds,  discounts,  or  recoupments  of Operating
Expenses  received  by Landlord  shall be  accounted  for by  Landlord  and
credited back to Tenant.  Tenant,  at reasonable  times and upon reasonable
notice, shall have the right to audit Landlord's books and records relating
to Operating  Expenses;  provided,  however,  in no event shall Landlord be
required to keep such underlying  receipts for Operating  Expenses beyond a
date which is three (3) years after Escrowee makes a disbursement  for such
Operating  Expenses.  The cost of capital  expenditures  shall be amortized
over the useful life of each such capital  expenditure  as  determined  for
federal income tax purposes.  Notwithstanding the foregoing, Landlord shall
not be entitled to payment from the Escrow Account for any costs of capital
improvements,  repairs,  or  maintenance  that  Tenant  would not have been
obligated to  undertake  under the standard of Care set forth in Section 11
of this Lease or for any other  Operating Costs which Tenant would not have
been  obligated  to pay under this Lease.  Notwithstanding  anything to the
contrary contained herein, until the expiration of 91 days after Landlord's
receipt of the Accelerated Payment, Tenant shall not make any claim against
Landlord that  Landlord has failed to use diligent  efforts to mitigate its
damages after the Event of

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Default which gave rise to the  Accelerated  Payment.  This provision shall
survive the termination of this Lease.

                           (C) In the event that Landlord exercises its
remedy under Subsection (iii)(A) of this Section, performance of Landlord's
obligations  under  Subsection  (iii)(B) of this Subsection shall be deemed
satisfaction of Landlord's duty to mitigate its damages.

                           (iv)   Landlord may sue for injunctive relief or to
recover damages for any loss resulting from the breach.

                  (c) Any agreement for an extension of the Term or for any
other  additional  period after the Term shall not thereby prevent Landlord
from  terminating this Lease for any reason specified in this Lease. If any
such right of termination  is exercised by Landlord  during the Term or any
extension  thereof,  Tenant's  right to any extension or additional  period
shall thereby be automatically  canceled.  Any such right of termination of
Landlord contained herein shall continue during the Term and any subsequent
extension hereof.

                  (d) The  failure  or delay by either  party to enforce or
exercise at any time any of the rights or remedies or other  provisions  of
this Lease shall not be  construed to be a waiver  thereof,  nor affect the
validity of any part of this Lease or the right of that party thereafter to
enforce each and every such right or remedy or other provisions.  No waiver
of any  default or breach of this Lease shall be held to be a waiver of any
other  default or breach.  No act or omission  by Landlord  during the Term
shall be deemed an acceptance  of a surrender of the Master Lease  Property
and no  agreement  to  accept  such a  surrender  shall be valid  unless in
writing and signed by Landlord.

                  (e) If either  party  defaults  under  this Lease and the
other party places the  enforcement of all or any part of this Lease or the
collection of any sum due or to become due under this Lease or the recovery
of possession of the Master Lease Property in the hands of an attorney, and
such party  prevails in litigation  concerning  such issue,  the defaulting
party  agrees  to  reimburse  the  prevailing   party  for  the  reasonable
attorney's fees incurred thereby.

                  SECTION 22.       BANKRUPTCY OR INSOLVENCY

                  Landlord and Tenant agree that the following  shall apply
in the event of the bankruptcy or insolvency of Tenant:

                  (a) If a petition  is filed by, or an order for relief is
entered  against  Tenant  under  Chapter 7 of the  Bankruptcy  Code and the
trustee of Tenant  elects to assume this Lease for the purpose of assigning
it, such assumption and assignment may be made only if all of the terms and
conditions of Subsections (b) and (d) below are satisfied. To be effective,
an election to assume this Lease must be in writing, addressed to Landlord, and

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all of the conditions herein stated,  which Landlord and Tenant acknowledge
to be commercially  reasonable,  must have been  satisfied.  If the trustee
fails so to elect to assume  this Lease  within  sixty (60) days after such
filing or order or such additional time as the Bankruptcy Court, for cause,
may fix,  this Lease  will be deemed to have been  rejected,  and  Landlord
shall then  immediately  be  entitled  to  possession  of the Master  Lease
Property  without  further  obligation  to Tenant or the trustee,  and this
Lease shall be terminated.  Landlord's  right to be compensated for damages
in the bankruptcy proceeding, however, shall survive such termination.

                  (b) If Tenant files a petition for  reorganization  under
Chapters 11 or 13 of the  Bankruptcy  Code, or if a pro ceeding filed by or
against Tenant under any other chapter of the Bankruptcy  Code is converted
to a  chapter  11 or 13  proceeding  and  Tenant's  trustee  or  Tenant  as
debtor-in-possession  fails to assume  this  Lease  within 60 days from the
date of the filing of such petition or conversion or such  additional  time
as the  Bankruptcy  Court,  for  cause,  may fix,  then the  trustee or the
debtor-in-possession  shall be deemed to have  rejected  this Lease.  To be
effective, any election to assume this Lease must be in writing,  addressed
to Landlord  and, if there has been a default  under the Lease,  all of the
following   conditions,   which  Landlord  and  Tenant  acknowledge  to  be
commercially reasonable, must have been satisfied:

                           (i)      The trustee or the debtor-in-possession has
                                    cured or has provided to Landlord adequate
                                    assurance that:

                                    (A)     It  will   cure  all   monetary
                                            defaults   under   this   Lease
                                            within   the   number  of  days
                                            specified  in Section  21(a)(I)
                                            of this  Lease from the date of
                                            assumption; and

                                    (B)     It will  cure  all  nonmonetary
                                            defaults   under   this   Lease
                                            within   the   number  of  days
                                            specified in Section  21(a)(ii)
                                            of this  Lease from the date of
                                            assumption.

                           (ii)     The trustee or the debtor-in-possession
                                    has   compensated   Landlord,   or  has
                                    provided    Landlord    with   adequate
                                    assurance   that   Landlord   will   be
                                    compensated  promptly for any pecuniary
                                    loss it has  incurred  arising from the
                                    default of Tenant, the trustee,  or the
                                    debtor-in-possession.

                           (iii)    The trustee or the debtor-in-possession
                                    has  provided  Landlord  with  adequate
                                    assurance of the future  performance of
                                    each of Tenant's obligations under this
                                    Lease; provided,
                                    however, that:


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                                    (A)     From  and  after  the  date  of
                                            assumption of this Lease, until
                                            the date of the  assignment  of
                                            this  Lease,  it shall  pay all
                                            monetary           obligations,
                                            including,  without limitation,
                                            the  Rent  payable  under  this
                                            Lease,  in advance on each date
                                            that such amounts are payable.

                                    (B)     It  shall  also   deposit  with
                                            Landlord,  as security  for the
                                            timely   payment  of  Rent,  an
                                            amount  equal to three  months'
                                            Base  Rent and  other  monetary
                                            charges   accruing  under  this
                                            Lease;

                                    (C)     If not  otherwise  required  by
                                            the  terms  of this  Lease,  it
                                            shall also pay in  advance,  on
                                            each day  that any  installment
                                            of  Base   Rent   is   payable,
                                            one-twelfth  (1/12) of Tenant's
                                            Imposition, Insurance and other
                                            obligations under this Lease.

                  (c)  If  the  trustee  or  the  debtor-in-possession  has
assumed this Lease,  pursuant to Subsection (a) or (b) above, and elects to
assign  Tenant's  interest  under this Lease or the estate  created by that
interest to any other person,  such interest or estate may be assigned only
if  the  intended  assignee  has  provided  adequate  assurance  of  future
performance of all of the terms, covenants, and conditions of this Lease.

For the  purposes of this  Subsection  (d),  "adequate  assurance of future
performance" means that Landlord has ascertained that each of the following
condition has been satisfied:

                           The  assignee  has  submitted a current
                           financial  statement which shows a net worth and
                           working capital in amounts  sufficient to assure
                           the  future   performance  by  the  assignee  of
                           Tenant's obliga tions under this Lease.

                  (d)  When, pursuant to the Bankruptcy Code, the trustee or
the  debtor-in-possession  is obligated to pay reasonable use and occupancy
charges  for the use of all or part of the  Master  Lease  Property,  it is
agreed that such  charges will not be less than the Base Rent as defined in
this Lease,  plus Additional Rent and other monetary  obligations of Tenant
included herein.

                  (e)  Except  to  the  extent  provided  by  law,  neither
Tenant's  interest  in this Lease nor any estate of Tenant  created in this
Lease  shall pass to any  trustee,  receiver,  assignee  for the benefit of
creditors, or any other person or entity, nor otherwise by operation of law
under the laws of any state having  jurisdiction  of the person or property
of Tenant, unless Landlord consents in writing to such transfer. Landlord's
acceptance  of Rent or any  other  payments  from  any  trustee,  receiver,

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assignee, person, or other entity will not be deemed to have waived, or waive,
either the requirement of Landlord's consent or Landlord's right to terminate
this Lease for any transfer of Tenant's  inter est under this Lease without
such consent.

                  SECTION 23.       SURRENDER OF MASTER LEASE PROPERTY

                  Upon the expiration or earlier termination of this Lease,
Tenant shall surrender the Master Lease Property to Landlord,  broom-clean,
in good order,  condition and repair (except for ordinary wear and tear and
conditions  which  existed  on  the  Master  Lease  Property  prior  to the
Effective  Date and subject to Sections  15 and 17),  free of all  Personal
Property and Restricted  Property (except for Restricted Property belonging
to any  Existing  Tenant or  Subtenant  whose  Existing  Lease or  Sublease
Landlord  has  expressly  agreed  in  writing  may  continue),  and free of
violation of Applicable  Laws in all material  respects  subject to Section
5(b)(iv).  To the extent  Tenant fails to comply with the  requirements  of
this  Section,  Landlord  may  restore  the Master  Lease  Property to such
condition at Tenant's expense.

                  SECTION 24.       NON-CONSENSUAL HOLDING OVER

                  In the event Tenant  remains in  possession of the Master
Lease  Property or any part thereof  without the consent of Landlord  after
the  expiration  or earlier  termination  of this  Lease,  Tenant  shall be
deemed,  at  Landlord's  election,  to hold the Master Lease  Property as a
tenant at sufferance subject to all of the terms, conditions, covenants and
provisions  of this Lease which shall be  applicable  during such time (the
"Non- Consensual Holdover Period"),  except that, for each month during the
Non-Consensual  Holdover  Period,  Tenant shall pay to Landlord one hundred
fifty  percent  (150%)  of  the  sum  of  the  last  current  full  monthly
installment of Base Rent plus  Additional  Rent,  which shall be payable to
Landlord  within  five  (5)  business  days of  notice  from  Landlord.  In
addition, such election shall not preclude Landlord from seeking, and shall
be cumulative  with, any other remedy under this Lease or granted by law or
in equity.  No holding  over by Tenant,  as  described  in this Section 24,
whether  with or without the consent of Landlord,  shall  operate to extend
this Lease.

                  SECTION 25.       QUIET ENJOYMENT

                  If and for so long as Tenant pays the prescribed Rent and
performs  or  observes  all  of  the  terms,   conditions,   covenants  and
obligations  of this Lease  required  to be  performed  or  observed  by it
hereunder, Tenant shall at all times during the Term have the peaceable and
quiet enjoyment, possession, occupancy and use of the Master Lease Property
without any inter  ference from  Landlord,  or anyone  claiming  through or
under  Landlord,  subject to any matters of record as of the Effective Date
to which this Lease is subject.

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                  SECTION 26.       NOTICES

                  Any notice, demand or request required or permitted to be
given  under  this Lease or by law shall be deemed to have been given if in
writing and delivered addressed to the party who is to receive such notice,
demand or request at the address  set forth below or at such other  address
as  Landlord or Tenant may  specify  from time to time by notice.  Delivery
hereunder  shall be deemed  to  include  pre-paid  courier  delivery  (by a
reputable  courier delivery  service),  pre-paid  overnight  delivery (by a
reputable  overnight delivery  service),  postage and fees paid U.S. Postal
Service  express mail or  certified  mail,  return  receipt  requested,  or
facsimile transmission with electronic  verification during normal business
hours,  if sent to the address of the  parties  designated  hereunder,  and
shall be deemed  received on the next business day such notice is delivered
or  refused  at such  address  except  notices  sent by fax shall be deemed
received upon electronic verification.

         Landlord:        LCOR Incorporated
                          6701 Democracy Boulevard
                          Bethesda, MD  20817
                          Attn: Mr. R. William Hard
                          Facsimile: (301) 897-3713

         with copies to:  Jones, Day, Reavis & Pogue
                          1450 G Street, N.W.
                          Washington, DC 20005-2088
                          Attn: Sigmund T. Weiner, Esq.
                          Facsimile: (202) 737-2832

                          LCOR Incorporated
                          300 Berwyn Park, Suite 104
                          Berwyn, PA 19312
                          Attention: Mr. Peter DiLullo
                          Facsimile: (610) 408-4420

         Tenant:          COMSAT Corporation
                          6560 Rock Spring Drive
                          Bethesda, MD 20817
                          Attention: General Manager Corporate
                                     Services
                          Facsimile: (301) 214-7147

         with a copy to:  COMSAT Corporation
                          6560 Rock Spring Drive
                          Bethesda, MD 20817
                          Attention: General Counsel

                          Facsimile: (301) 214-7128

Any copies required to be sent as above provided are for the convenience of
the  parties  and no such copy  shall  constitute  adequate  notice for the
purposes of this Section.

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                  SECTION 27.       HAZARDOUS MATERIALS

                  Landlord  and Tenant agree as follows with respect to the
existence or use of "Hazardous Material" on the Master Lease Property or in
the Main Building.

                  (a)  If  the  use,  storage,  handling,   generation,  or
disposal of Hazardous  Material on or in the Master Lease  Property  during
the  Term  results  in the  release  or  threatened  release  of  Hazardous
Materials  at,  on or under the  Master  Lease  Property  in  violation  of
Applicable  Law,  or  otherwise  necessitates  investigation  or cleanup of
Hazardous  Material  as  required  under  Applicable  Law   ("Environmental
Conditions"),  Tenant shall  indemnify,  defend and hold Landlord  harmless
from any and all  claims,  judgments,  damages,  penalties,  fines,  costs,
liabilities  or  losses  (including,   without  limitation,  sums  paid  in
settlement of claims,  attorneys' fees, consultant fees and expert fees but
excluding  consequential  damages  and  any  injury  to  the  value  of the
Property,  provided that this clause shall not be construed as reducing the
Remediation  Obligation)  which arise  during or after the Term as a direct
result  thereof.  This  indemnification  of  Landlord  by Tenant  includes,
without  limitation,  reasonable  costs  incurred  in  connection  with any
investigation  of site  conditions  or any  cleanup,  remedial,  removal or
restoration  work  required  by any  federal,  state or local  governmental
agency because of Hazardous  Material present in the soil or groundwater on
or under the Master  Lease  Property or in any  improvements  on the Master
Lease  Property.  This  indemnification,  however,  shall  not apply to any
Environmental Conditions caused by the acts or omissions of Landlord or its
Agents. The indemnification  and hold harmless  obligations of Tenant under
this Section 27 shall survive any termination of this Lease for a period of
twenty-four  (24)  months  after  the  termination.   At  the  end  of  the
twenty-four  (24) month period,  this  indemnification  and all of Tenant's
obligations  under  this  Section  shall  expire,   except  as  to  matters
specifically  made the subject of a lawsuit filed against Tenant before the
expiration  of the  twenty-four  (24) month  period.  Without  limiting the
foregoing,  if the use,  storage,  handling,  generation,  or  disposal  of
Hazardous  Material  on or in the  Master  Lease  Property  during the Term
results  in  any  Environmental   Conditions,   then,   provided  that  the
Environmental  Condition is not caused by the acts or omissions of Landlord
or its Agents, Tenant shall promptly take all actions, at its sole expense,
as are necessary to return the Master Lease Property to  substantially  the
condition  existing  prior to  thereto or to such  other  condition  as may
satisfy  the  applicable   governmental   authorities   (the   "Remediation
Obligation").  Landlord's approval of such actions shall first be obtained,
which approval shall not be unreasonably withheld.  Nothing in this Section
shall be deemed to prohibit or limit any action by Tenant against any party
or parties responsible for the contamination.

                  (b)  Landlord  and  Tenant   acknowledge   that  asbestos
containing  materials  ("ACM") are located in certain  portions of the Main
Building. Except for the ACM to be removed by Tenant as part of the Roof Work,
and so long as not required by Applicable Laws, Tenant shall not be required to

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remove or otherwise treat or abate the other ACM located in the Main Building;
provided, that during the Term Tenant covenants and agrees (i) to continue
implementation of the Operations and Maintenance  Plan described in Exhibit J 
attached hereto and made a part hereof at all times in compliance  with 
Applicable Laws in all material respects; (ii) to take such actions with 
respect to the ACM as may be  necessary to comply with Applicable Laws  and to
maintain the habitability of the Main Building; and (iii) to indemnify and hold
Landlord harmless (except to the extent caused by Landlord) from any and all
claims, judgments,   damages,   penalties,  fines,  costs,  liabilities  or
losses (including,  without limitation, reasonable attorneys' fees and  costs)
arising out of or relating to claims for tort  liability  brought by Tenant
or its Agents for events  occurring or accruing during the Term as a result
of the existence of the ACM in the Main Building.

                  (c) Landlord shall have the right,  at any time, to cause
the groundwater, soil, improvements and air at the Master Lease Property to
be  investigated  to detect the presence of Hazardous  Material  during the
Term, including,  but not limited to, the installation of testing wells and
other  devices  in  locations  selected  by  Landlord  at  Landlord's  sole
discretion. Landlord shall supply Tenant with copies of final investigation
reports. The cost of such investigations and of the maintenance, repair and
replacement  of such  wells and other  devices  shall be fully  paid for by
Landlord,  unless Landlord's investigations reveal Environmental Conditions
which Tenant is obligated to remediate  under this Section.  In that event,
Tenant,  within 30 days after receiving a copy of such investigation report
and a statement  of charges  from  Landlord,  shall pay for the cost of the
investigation.  Any dispute under this  Subsection  shall be resolved under
the arbitration proceedings set forth in Subsection 11(c).

                  (d) As used herein,  the term "Hazardous  Material" means
any  hazardous  or toxic  substance,  material or waste which is or becomes
regulated by any local governmental authority, the State of Maryland or the
United  States  Government  or other  Applicable  Law. The term  "Hazardous
Material" includes,  without limitation, any material or substance which is
(i)  designated as a "hazardous  substance"  pursuant to Section 307 of the
Federal  Water  Pollution  Control Act, 33 U.S.C.  Section 1251 et seq. (33
U.S.C.  Section  1317),  (ii)  defined as a "hazardous  waste"  pursuant to
Section 3001 of the Federal  Solid Waste  Disposal  Act, 42 U.S.C.  Section
6901 et seq. (42 U.S.C.  Section  6921),  or (iii)  defined as a "hazardous
substance"  pursuant  to  Section  101 of the  Comprehensive  Environmental
Response,  Compensation  and Liability Act, 42 U.S.C.  Section 9601 et seq.
(42  U.S.C.   Section  9601),   or  (iv)  petroleum,   petroleum   product,
polychlorinated biphenyls or urea formaldehyde.

                  (e) Within 30 days of the  Expiration  Date, if requested
by Landlord, Tenant shall remove all fuel oil and other liquid contents and
Hazardous  Materials  (collectively,   the  "Contents")  from  all  now  or
hereafter active underground storage tanks located on the Master Lease Property

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and dispose of such contents off of the Master Lease Property and in accordance
with Applicable Laws. Tenant shall  not be  obligated  to  remove,  close or
take any  other  action  to de-commission  the tanks during or after the Term.
If, however,  during the Term governmental authorities require such removal,
closure or other action and the  requirement  is not prompted by  Landlord's
request to remove the Contents or any Development by Landlord or its Agents,
Tenant shall comply with such request subject to Subsection 5(B)(iv)(d).

                  (f)  Notwithstanding  anything  contained  in this Lease,
Tenant shall have no obligation or liability to Landlord with respect to:

                           (i)      Any Hazardous Material which may exist on 
the Master Lease Property as of the Effective  Date,  except to the extent that
Tenant is  specifically  required to take action  regarding  such Hazardous
Material by the governmental authority having jurisdiction.

                           (ii)     Hazardous Material that migrates, flows,
percolates,  diffuses  or in any way moves on to or under the Master  Lease
Property from sources outside the Master Lease Property.

                           (iii) Hazardous Material present on or in the
Master  Lease  Property as a result of any  discharge,  dumping or spilling
(whether  accidental or  otherwise) on areas of the Master Lease  Property,
except the Main Building Area, by persons other than Tenant or its Agents.

                  SECTION 28.       RIGHT TO RENEW TERM

                  (a)  Provided  that this  Lease is then in full force and
effect,  and  provided  that no Event of Default  exists at the time of the
Renewal Notice or the date of  commencement  of the Renewal Term,  Landlord
hereby grants to the Tenant an option (the  "Renewal  Option") to renew the
Initial Term of this Lease on the same terms,  conditions and provisions as
contained in this Lease,  except as noted herein,  for a period of five (5)
years after the Expiration  Date of the Initial Term (the "Renewal  Term"),
which  Renewal  Option  period shall,  except as provided  below,  commence
immediately  following the  expiration of the Initial Term and end at 11:59
p.m. of the fifth anniversary of such date.

                  (b) The Renewal Option shall be exercised,  if at all, by
written  notice  (the  "Renewal  Notice")  from  Tenant to  Landlord of its
election, said notice to be given no later than the twenty-four (24) months
prior to the Expiration  Date of the Initial Term. If the Renewal Notice is
not so given by Tenant to  Landlord,  the  Renewal  Option  shall be deemed
waived.

                  (c) The  Renewal  Term  shall  be upon  the  same  terms,
covenants and conditions as provided in this Lease except as follows:

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                           (i)  Tenant shall not have any further right to
extend the Term or holdover after the end of the Term.

                           (ii) The annual Base Rent for the first year of
the Renewal  Term shall be equal to the lesser of (i) the Fair Market Rent,
and (ii) one hundred two and 75/100ths  percent  (102.75%) of the Base Rent
rate in effect under this Lease  immediately  prior to  commencement of the
Renewal Term; but in no event less than the annual Base Rent rate in effect
during the sixth Lease Year of the Initial Term (as reflected in Subsection
4(a)(vi)).

                           (iii) The annual Base Rent shall be increased
during the Renewal Term by two and 75/100ths  percent (2.75%) per year on a
cumulative compounded basis.

                  (d) Landlord  and Tenant  shall  attempt in good faith to
agree as to the Fair Market Rent,  and if Landlord and Tenant fail to agree
as to the Fair Market Rent at least six (6) months prior to the  Expiration
Date of the Initial  Term (the  "Arbitration  Deadline"),  Fair Market Rent
shall be determined as follows:

                           (i)   Fair Market Rent shall be the triple net rent
which  would be  asked of  tenants  as of the date of  commencement  of the
Renewal Term for space  comparable to the Main Building under five (5) year
leases in the  Germantown/Clarksburg  areas of Montgomery County, Maryland,
taking into account the size of the premises being leased by Tenant and the
value of brokerage  commissions,  rental  abatements,  rental credits,  and
tenant allowances, if any, being offered or paid under such leases.

                           (ii)   Tenant shall initiate the process to
determine  Fair Market Rent by giving  written  notice to Landlord  setting
forth  the name and  address  of a  leasing  broker  selected  by Tenant to
determine  the Fair  Market  Rent.  Within  five (5) days after  receipt of
Tenant's  notice,  Landlord  shall notify Tenant in writing of the name and
address of a leasing  broker  selected by Landlord  to  determine  the Fair
Market Rent. Each broker shall  independently make his or her determination
of the Fair Market Rent within  twenty (20) days after the  appointment  of
Landlord's  broker.  The Fair Market Rent shall be deemed to be the average
of the two  determinations  unless  the  higher of such  determinations  is
greater  than  one  hundred  five  percent  (105%)  of  the  lower  of  the
determinations.  If the higher  determination  is greater  than one hundred
five (105%) of the lower  determination,  the brokers  selected by Landlord
and Tenant shall together  select a third broker within five (5) days after
rendering their  determinations.  The third broker shall have ten (10) days
to make his or her  determination  of the Fair  Market  Rent and upon  such
determination,  the Fair  Market  Rent  shall be  deemed  to be the  median
determination  made by the three (3)  brokers.  If  Landlord  fails to give
Tenant  timely  notice of  Landlord's  selection  of a broker,  the  broker
selected by Tenant shall solely determine Fair Market Rent.

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                          (iii) Each broker appointed pursuant to this
Subsection  shall  be a  disinterested  broker  licensed  in the  State  of
Maryland having  recognized  competence in the field of commercial  leasing
and a minimum of ten (10) years  experience as a commercial  leasing broker
or agent in the Montgomery  County area.  Each party shall pay for the cost
of the broker which it selects and the parties shall share equally the cost
of the third broker, if any.

                  (e) Upon the valid  exercise  by  Tenant  of the  Renewal
Option,  at the request of either party hereto and within  thirty (30) days
after  such  request,  Landlord  and  Tenant  shall  enter  into a  written
supplement to this Lease incorporating the terms, conditions and provisions
applicable  to the  Renewal  Term as  determined  in  accordance  with  the
provisions of this Section;  provided,  that if the amount of Base Rent for
the first year of the Renewal Term has not then been set, such amount shall
be entered into such supplement when determined.

                  SECTION 29.       SECURITY DEPOSIT

                  If at any time  during  the Term,  the  credit  rating of
Tenant's  corporate  debt drops below BBB as rated by Standard & Poor's (or
the  equivalent  rating by any other national  rating agency  designated by
Landlord),  upon  notice from  Landlord,  Tenant  shall  deposit a sum with
Landlord  equal to one month's  installment of the then  applicable  annual
Base Rent  ("Security  Deposit"),  as  security  for the full and  faithful
performance by Tenant, of each and every term,  covenant,  and condition of
this Lease.  If there an event of Default,  Landlord  may use the  Security
Deposit as payment of any Rent or other payment due from Tenant to Landlord
or to otherwise  cure any default of Tenant  hereunder.  To the extent that
any of the Security Deposit is used for this purpose, Tenant shall pay such
amount to Landlord  along with the next  month's Rent in order to replenish
the Security  Deposit to the original  amount stated  herein.  The Security
Deposit  shall  be  returned  to  Tenant  within  thirty  (30)  days of the
Expiration  Date or earlier  termination  of this Lease to the extent  that
such  amount is not  depleted  in order to  remedy  any  default  by Tenant
hereunder.

                  SECTION 30.       MISCELLANEOUS GENERAL PROVISIONS

                  (a) Payments Deemed Rent. Any amounts of money to be paid
by Tenant to Landlord pursuant to the provisions of this Lease,  whether or
not such payments are  denominated  Rent or Additional  Rent and whether or
not  they  are to be  periodic  or  recurring,  shall  be  deemed  Rent  or
Additional  Rent for purposes of this Lease;  and any failure to pay any of
same shall  entitle  Landlord  to exercise  all of the rights and  remedies
afforded  hereby or by law or in equity for the collection and  enforcement
of Tenant's  obligation  to pay Rent.  Tenant's  obligation to pay any such
Rent or  Additional  Rent  pursuant to the  provisions  of this Lease shall
survive the expiration or other termination of

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this Lease and the surrender of possession of the Master Lease Property.

                  (b)  Interest  on  Deposits.  Any amount  deposited  with
Landlord under this Lease shall be held by Landlord in a federally insured,
interest bearing account.  Any interest earned on such deposit shall accrue
to Tenant and shall be transferred to Tenant  promptly after the Expiration
Date or such earlier time as may be specified in this Lease unless Landlord
is required by  Applicable  Laws to return such  interest to Tenant  sooner
than stated  herein.  Any amount  deposited with Mortgagee by Tenant (or by
Landlord  on  Tenant's  behalf)  shall  be held by  Mortgagee  pursuant  to
Applicable Laws and pursuant to the security documents between Landlord and
Mortgagee.  No interest shall accrue unless  required by Applicable Laws or
such security documents.  Notwithstanding the foregoing, any amounts placed
in the Escrow  Account  shall be governed by the  provisions  of Subsection
21(b)(iii)(B).

                  (c)      Landlord Cross Default.  Any default by Landlord
under the Facilities Lease shall be a default by Landlord under
this Lease.

                  (d)  Estoppel  Letters.  Tenant  shall,  within  ten (10)
business days following written request from Landlord, execute, acknowledge
and  deliver to Landlord or to any then  existing  or  prospective  lender,
investor or  purchaser,  with respect to the Master  Lease  Property or any
part thereof,  designated by Landlord,  a written statement  certifying (i)
that  this  Lease is in full  force  and  effect  (if such is the case) and
unmodified (or, if modified, stating the nature of such modification), (ii)
the date to which Rent has been paid, (iii) that there are not, to Tenant's
actual knowledge, any uncured defaults by Landlord or Tenant (or specifying
such defaults if any are claimed),  and (iv) such other matters as Landlord
may reasonably  request.  Any such statement may be relied upon by any such
then existing or prospective lender, investor or purchaser. If Tenant fails
to deliver such  statement  within the ten (10)  business day period and if
following the  expiration of that period  Landlord  gives a second  written
request for the statement and Tenant fails to deliver the statement  within
five (5) business days after the second request,  Tenant shall conclusively
be deemed to have responded that this Lease is in full force and effect and
unmodified and that there are no uncured defaults in Landlord's performance
hereunder.

                  (e) Brokers.  Each party  represents  and warrants to the
other that no broker  procured this Lease on its behalf and that such party
had no conversations or negotiations with any broker concerning the leasing
of the Master Lease Property, other than Barnes, Morris, Pardoe and Foster,
which firm is receiving a  commission  from Tenant in  connection  with the
Purchase  and  Sale  Agreement  and  is not  entitled  to a  commission  in
connection  with this Lease.  Each party shall  indemnify the other against
liability in connection with a breach of its representation and

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warranty  in  this  Subsection  and in  connection  with  any  claim  for a
brokerage  or finder's  commission  or fee  arising  out of its acts.  This
indemnification shall survive any termination of this Lease.

                  (f) Applicable Law. This Lease and all matters  pertinent
thereto shall be construed and enforced in accordance  with the  Applicable
Laws of the State of Maryland, excluding choice of laws principles.

                  (g) Entire Agreement.  This Lease, including all exhibits
hereto,  constitutes the entire  agreement  between the parties hereto with
respect to the leasing of the Master Lease Property and may not be modified
except by an instrument in writing executed by the parties hereto.

                  (h) Binding Effect.  This Lease and the respective rights
and  obligations of the parties hereto shall inure to the benefit of and be
binding upon the  successors  and assigns of the parties  hereto as well as
the parties themselves; subject, however, to Subsection (o) below.

                  (i) Survival. All provisions of this Lease which by their
express terms survive  termination  of this Lease or which by the operation
of their terms are  intended to be  performed,  in whole or in part,  after
termination of this Lease, shall survive any termination of this Lease.

                  (j) Severability. If any provision of this Lease shall be
held to be invalid,  void or unenforceable,  such provision shall be deemed
reformed  to be valid,  in effect  and  enforceable,  and to be as close in
meaning  and  intent as the  defective  provision  and still the  remaining
provisions  hereof  shall not be affected or impaired,  and such  remaining
provisions shall remain in full force and effect.

                  (k)  Headings,  Gender,  etc. As used in this Lease,  the
word "person"  shall mean and include,  where  appropriate,  an individual,
corporation,  partnership or other entity;  the plural shall be substituted
for the singular,  and the singular for the plural, where appropriate;  and
words of any gender shall include any other gender. The topical headings of
the  several  paragraphs  of this  Lease are  inserted  only as a matter of
convenience and reference, and do not affect, define, limit or describe the
scope or intent of this Lease.  References  in this Lease to  Sections  and
Subsections are references to Sections and Subsections of this Lease.

                  (l) Waiver of Jury. To the extent permitted by Applicable
Laws,  each of Landlord and Tenant hereby waives any right it may have to a
jury  trial  in  the  event  of  litigation  between  Landlord  and  Tenant
pertaining to this Lease.

                  (m)      Landlord's Right to Cure.  Landlord may, but shall
not be obligated to, cure any default by Tenant, specifically including,  but

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not  by  way  of  limitation,   Tenant's  failure  to  pay Impositions,  obtain
Insurance,  Care for the Master  Lease  Property,  or satisfy lien claims,
after complying with any applicable  notice and cure provisions  established
under this Lease; and whenever Landlord so elects, all  reasonable out of
pocket costs and expenses paid by Landlord in curing such default,  including,
without limitation,  reasonable attorneys' fees, shall be Additional Rent due
on the next scheduled Rent payment date.

                  (n)  Relationship of Parties.  Nothing  contained  herein
shall be deemed or construed by the parties hereto, nor by any third party,
as creating the  relationship of principal and agent or of partnership,  or
of joint venture by the parties hereto, it being understood and agreed that
no  provision  contained  in this Lease nor any act of the  parties  hereto
shall be deemed to create any  relationship  other than the relationship of
Landlord and Tenant.

                  (o) Landlord Means Owner.  The term "Landlord" as used in
this lease,  so far as covenants or obligations on the part of Landlord are
concerned, shall be limited to mean and include only the owner or owners at
the time in question of the Master Lease  Property and, in the event of any
transfer or  transfers  of the title to all of the Master  Lease  Property,
Landlord  herein  named  (and  in  case  of  any  subsequent   transfer  or
conveyances,  the then grantor) shall be automatically  freed and relieved,
from and after the date of such transfer or conveyance, of all liability as
respects the  performance  of any covenants or  obligations  on the part of
Landlord  contained in this Lease  thereafter to be performed  (but not any
liabilities accrued prior to the date of transfer); provided that any funds
in the  hands  of such  Landlord  or the then  grantor  at the time of such
transfer,  in which  Tenant has an  interest,  shall be turned  over to the
grantee,  and any amount  then due and payable to Tenant by Landlord or the
then grantor under any  provisions  of this Lease,  shall be paid to Tenant
and  further  provided  that the  transferee  assumes in writing all of the
covenants  and  obligations  of Landlord to observed  and  performed on and
after the date of transfer.

                  (p) References to Size.  Landlord and Tenant  acknowledge
and agree that any  references  in this Lease to the size of the  Property,
the Main Building  Area,  the Main Building or any portion  thereof are for
convenience only and regardless of whether the actual size of such areas is
greater or less than the size stated in this Lease,  all obligations of the
parties hereunder, including without limitation, the obligation to pay Rent
shall remain the same and shall not be affected by any errors in references
to size.

                  (q) Unavoidable  Delays.  For purposes of this Lease, the
term  "Unavoidable  Delays" shall mean delays caused by strikes,  lockouts,
acts  of  God,  inability  to  obtain  labor  or  materials,   governmental
restrictions or inaction,  enemy action,  civil commotion,  fire, terrorist
action, epidemic, public utility failure,  unavoidable  casualty,  moratorium

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or similar  laws  prohibiting performance,  weather conditions or any other
similar matter which shall be beyond the  reasonable  control of Landlord or
Tenant, as the case way be; but the lack or  insufficiency of funds shall not 
constitute an Unavoidable Delay.

                  (r) Landlord's Approvals.  Wherever Landlord's consent or
approval  are  required  under  this  Lease,   Landlord  shall  approve  or
disapprove  the matter within ten (10) business days after Tenant  requests
the  consent or approval  in  writing.  If Landlord  fails to do so and if,
following the expiration of the ten (10) business day period,  Tenant gives
a second written  request for the consent or approval and Landlord fails to
approve or  disapprove  the matter  within five (5) business days after the
second request,  Landlord shall conclusively be deemed to have consented to
or approved the matter, as the case may be.

                  (s) Rate of  Interest.  If any amount owed by Landlord to
Tenant under this Lease remains  unpaid after such amount is due and notice
thereof  has been given to  Landlord,  the  outstanding  amount  shall bear
interest at the  Stipulated  Rate from the date such amount is due and such
notice is given to the date such amount is paid.

                  (t)  Cooperation  of  Parties.  Whenever  the parties are
required to cooperate  with each other under this Lease but are entitled to
reimbursement  for their  out-of-pocket  costs to third parties,  the party
that is  obligated  to  cooperate  shall  provide an estimate of such third
party costs to the party  requesting such  cooperation and obtain the prior
written  approval from such other party not to be unreasonably  withheld or
delayed before such costs are incurred.

                  (u)  Reconciliation.  Nothing in this Lease shall prevent
or impair Tenant from performing its obligations or observing its covenants
under the  Existing  Space  Leases.  Further,  nothing in this Lease  shall
prevent or impair any of the Existing  Tenants from exercising their rights
and privileges under the Existing Space Leases. No such action by Tenant or
the Existing  Tenants in accordance with the Existing Space Leases shall be
deemed to be a breach or default by Tenant under this Lease.

                  (v) Memorandum of Lease. Upon request of either party the
other party shall promptly  execute and deliver a memorandum or other short
form  version of this  Lease  setting  forth the basic  terms of this Lease
excluding Rent. The party recording such memorandum, short form version, or
other  document  giving  notice  of  this  Lease  shall  pay  any  and  all
recordation and transfer taxes due in connection with such recordation.

                  (w)  Financial  Reports.  In the event that  Tenant is no
longer a publicly  traded  company with common stock  trading on either the
New York Stock  Exchange,  the American  Stock Exchange or the NASDAQ Stock
Exchange (or, in the event the Tenant's stock is no longer traded on such 

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exchanges, or a successor or reasonably equivalent exchange), Tenant shall
supply Landlord,  within ten (10) business days of Landlord's  request
therefor (to be no more  frequent than once per year), copies of Tenant's most
recent  financial  reports.  Such reports shall (i) include an income
statement,  balance sheet,  statement owner's equity and statement  of cash
flows,  (ii)  shall be audited  by a  certified  public accountant  or, to the
extent audited  Financial  Reports are not otherwise obtained by Tenant for
other  purposes,  certified  by the chief  financial officer of  Tenant,  to
his/her  knowledge,  as being  true,  correct  and complete financial  reports,
and (iii) shall be dated no later than twelve months prior to Landlord's
request.  Notwithstanding the foregoing,  in the event that Landlord  requests
such  financial  reports  within one hundred twenty (120) days after Tenant's
fiscal year end,  Tenant shall have up to one  hundred  twenty  (120) days
from such  fiscal  year end to supply such reports to  Landlord;  provided
Tenant has given  Landlord its most recent financial reports and such reports
are not dated earlier than twelve (12) months prior to Tenant's fiscal year end.

                  (x)  Landlord's  Affiliates.   Notwithstanding   anything
contained  in  this  Lease  to the  contrary,  any  act or  omission  of an
affiliate  of  Landlord  on any  Excluded  Areas  shall not be a default of
Landlord under this Lease. In no event shall this provision be construed in
any  manner as a waiver of any right  that  Tenant  has at law or in equity
against such affiliate as a result of such act or occurrence.


                          [SIGNATURE PAGE FOLLOWS]

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<PAGE>
 
                  IN WITNESS  WHEREOF,  the parties hereto have caused this
Lease to be executed as of the day and year stated herein.

                                 LANDLORD:

                                 LCOR CLARKSBURG L.L.C.
                                 By: Clarksburg Management, Inc.

                                 By:/s/ Michael T. Goulder

                                 Name: Michael T. Goulder

                                 Title: Vice President



                                 TENANT:

                                 COMSAT CORPORATION


                                 By: /s/ Allen E. Flower

                                 Name: Allen E. Flower

                                 Title: Vice President and
                                        Chief Financial Officer



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                                 SCHEDULE I
                               Defined Terms

         AAA:                             Section 11(c)
         ACM:                             Section 27(b)
         Accelerated Payment:             Section 21(b)(iii)(A)
         Additional Easements:            Section 6(f)
         Additional Rent:                 Section 4(b)
         Adequate Assurance of
           Future Performance:            Section 22(d)
         All Risks Policy:                Section 14(a)(i)
         Alterations:                     Section 13(a)
         Applicable Laws:                 Section 5(b)(iv)
         Appurtenances:                   Section 6(d)
         Arbitration Deadline:            Section 28(d)
         Architect:                       Section 15(b)(i)
         Assignment:                      Section 19(b)
         Base Rent:                       Section 4(a)
         Blanket Policy:                  Section 14(e)
         Building A, B or C:              Definitions of Main Building
         Care, Care for,
           Care of:                       Section 11(a)
         Communication Facilities:        Section 6(a)(iii)
         Comparable Buildings:            Section 11(a)
                  Comparable Properties:  Section 11(b)
         Contents:                        Section 27(e)
         Damage:                          Section 15(a)
         Declaration:                     Section 11(b)
         Default Measuring Period:        Section 21(b)(iii)(B)
         Development:                     Section 6(a)
         Effective Date:                  Preamble
         Environmental Conditions:        Section 27(a)
         Escrow Account:                  Section 21(b)(iii)(B)
         Escrowee:                        Section 21(b)(iii)(B)
         Events of Default:               Section 21(a)
         Existing Space Leases:           Section 19(a)
         Existing Tenants:                Section 19(a)
         Facilities Lease:                Section 21(a)(iii)
         Flood and Earthquake
           Insurance:                     Section 14(f)
         Flood Zone:                      Section 14(f)
         Hazardous Material:              Section 27 and 27(d)
         Holdover Notice:                 Section 3(b)(i)
         Holdover Period:                 Section 3(b)(i)
         Holdover Space:                  Section 3(b)(ii)
         Impositions:                     Section 7(a) and (d)
         Indemnifying Party:              Section 16(c)
         Indemnitee:                      Section 16(c)
         Indemnity Payment:               Section 16(c)
         Initial Term:                    Section 3(a)
         Institutional Mortgagee:         Section 15(c)(i)
         Insurable Casualty:              Section 15(h)
         Insurance:                       Section 14(a)
         Insurance Notice:                Section 14(g)

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                            SCHEDULE I (cont'd)

         Insurance Trustee:               Section 15(c)
         Landlord:                        Preamble; Section 30(o)
         Landlord Approved SNDA:          Section 19(b)
         Lease:                           Preamble
         Lease Renewal:                   Section 19(d)
         Lease Year:                      Section 3(c)
         Liability Policy:                Section 14(a)(ii)
         Measuring Period:                Section 19(d)
         Mitigation Leases:               Section 21(b)(iii)(B)
         Mortgagee:                       Section 7(e)(i)
         Non-Broker Sublease:             Section 19(b)
         Non-Consensual Holdover
           Period:                        Section 24
         Operating Expenses:              Section 21(b)(iii)(B)
         Personal Property:               Section 13(b)
         Plans:                           Section 13(a)(i)
         Post Default Leases:             Section 21(b)(iii)(B)
         Preapproved Alterations:         Section 13(a)
         Prime Rate:                      Section 4(h)
         Profit:                          Section 19(d)
         Purchase and Sale
           Agreement:                     Recital (a)
         Remediation Obligation:          Section 27(a)
         Renewal Notice:                  Section 28(b)
         Renewal Option,
           Renewal Term:                  Section 28(a)
         Rent:                            Section 4(b)
         Rent Insurance:                  Section 14(a)(iv)
         Replacement Value:               Section 14(a)(i)
         Requisition:                     Section 15(c)(i)
         Restoration:                     Section 15(a)
         Restricted Areas:                Section 12(a)
         Restricted Property:             Section 13(b)
         Roof Based Facilities:           Section 13(a)
         Roof Work:                       Section 11(e)
         Security Deposit:                Section 29
         Seismic Activity Zone:           Section 14(f)
         Signs:                           Section 9(a)
         Standard Rating:                 Section 14(g)
         Stipulated Rate:                 Section 4(h)
         Sublease:                        Section 19(b)
         Sublease Arbitration
           Deadline:                      Section 19(c)
         Subject Space:                   Section 19(d)
         Subtenant:                       Section 19(e)
         Taken, Taking:                   Section 17(a)(i)
         Tax and Insurance
           Holdbacks:                     Section 21(b)(iii)(B)
         Tenant:                          Preamble
         Tenant Approved SNDA:            Section 20(a)
         Tenant's Knowledge:              Section 15(c)(ii)
         Term:                            Section 3(a)
         Third Party Claim:               Section 16(d)(i)

Version 10
<PAGE>
 
         Triggering Event:                  Section 6(b)
         Unavoidable Delays:                Section 30(q)
         Utilities:                         Section 8(a)

Version 10
<PAGE>
 
                                Schedule II
                                Deductibles


I.       All Risk Policy                             $100,000
         Flood and Earthquake Insurance              $150,000


II.      In the event that Tenant's corporate debt drops below BB, as rated
         by an Approved  Credit Rating  Agency,  the following  deductibles
         shall apply:

         All Risk Policy                             $25,000
         Flood and Earthquake Insurance              $50,000


Version 10
<PAGE>
 
                            SCHEDULE OF EXHIBITS



   EXHIBIT                                             SECTION

   Exhibit A         (Description of Land)             1(a)

                  Exhibit B (Description of Main       1(a)
                             Building Area)

                  Exhibit C (Description of            1(a)
                             Installations Premises)

                  Exhibit D  Intentionally Omitted

                  Exhibit E  (Wire Instructions)       4(g)

                  Exhibit F  (Roof Work)               11(e)

                  Exhibit G  (Existing Space Leases)   19(a)

                  Exhibit H  (Landlord Approved SNDA)  19(b)

                  Exhibit I  (Tenant Approved SNDA)    20(a)

                  Exhibit J  (Operations and           27(b)
                              Maintenance Plan)


Version 10

<PAGE>
 
                                                                  EXHIBIT 10.51


                         FACILITIES LEASE AGREEMENT

                               BY AND BETWEEN

                    LCOR CLARKSBURG L.L.C., AS LANDLORD

                                    AND

                       COMSAT CORPORATION, AS TENANT





                  CLARKSBURG, MONTGOMERY COUNTY, MARYLAND
<PAGE>
 
                             TABLE OF CONTENTS




         INTRODUCTION
         Section 1.      DEFINITIONS........................................1
         Section 2.      LEASE OF INSTALLATIONS PREMISES....................2
         Section 3.      TERM...............................................2
         Section 4.      RENT...............................................3
         Section 5.      USE OF THE INSTALLATIONS PREMISES..................5
         Section 6.      DEVELOPMENT; DESIGNATION OF THE EXCLUDED
                              AREAS.........................................7
         Section 7.      TAXES AND IMPOSITIONS..............................9
         Section 8.      UTILITIES.........................................12
         Section 9.      SIGNS.............................................13
         Section 10.     AS-IS CONDITION OF INSTALLATIONS
                              PREMISES.....................................13
         Section 11.     REPAIRS, MAINTENANCE AND MANAGEMENT...............14
         Section 12.     ACCESS TO INSTALLATIONS PREMISES..................15
         Section 13.     ALTERATIONS AND PERSONAL PROPERTY.................16
         Section 14.     INSURANCE.........................................17
         Section 15.     DAMAGE OR DESTRUCTION.............................20
         Section 16.     INDEMNIFICATION...................................21
         Section 17.     CONDEMNATION......................................25
         Section 18.     LIENS.............................................26
         Section 19.     EXISTING SPACE LEASES; ASSIGNMENT AND
                              SUBLETTING...................................27
         Section 20.     SUBORDINATION OR SUPERIORITY OF LEASE.............28
         Section 21.     DEFAULTS AND REMEDIES.............................29
         Section 22.     BANKRUPTCY OR INSOLVENCY..........................34
         Section 23.     SURRENDER OF INSTALLATIONS PREMISES...............36
         Section 24.     NON-CONSENSUAL HOLDING OVER.......................36
         Section 25.     QUIET ENJOYMENT...................................37
         Section 26.     NOTICES...........................................37
         Section 27.     HAZARDOUS MATERIALS...............................38
         Section 28.     RIGHT TO RENEW TERM...............................40
         Section 29.     SECURITY DEPOSIT..................................41
         Section 30.     MISCELLANEOUS GENERAL PROVISIONS..................41
         SCHEDULE I
         SCHEDULE OF EXHIBITS
<PAGE>
 
                         FACILITIES LEASE AGREEMENT


                  THIS FACILITIES LEASE AGREEMENT (this "Lease") is entered
into  and  made  effective  as of the  12th  day of  September,  1997  (the
"Effective  Date"),  by and  between  LCOR  CLARKSBURG  L.L.C.,  a Delaware
limited liability company  ("Landlord") and COMSAT Corporation,  a District
of Columbia corporation ("Tenant").

                                WITNESSETH:

                  (a) Prior to but contemporaneously with the execution and
delivery  of this  Lease,  Tenant sold and  transferred  the  Installations
Premises to Landlord  pursuant to that certain  Agreement of Sale dated the
Effective  Date,  by and  between  Tenant,  as  seller,  and  Landlord,  as
purchaser (the "Purchase and Sale Agreement").

                  (b)  Landlord  desires  to lease to  Tenant,  and  Tenant
desires to lease back from Landlord, the Installations Premises, all as set
forth and on the terms and conditions contained in this Lease.

                  NOW THEREFORE,  in  consideration  of the mutual promises
set forth in this  Lease and other  good and  valuable  consideration,  the
receipt and sufficiency of which are  acknowledged by each party,  Landlord
and Tenant agree as follows:

                  SECTION 1.        DEFINITIONS

                  (a) The following terms shall have the meanings  ascribed
thereto below:

                  Agents:  The agents, employees, contractors,
subcontractors, affiliates, licensees and invitees of each party
(and in the case of Tenant, subtenants).

                  Auxiliary  Buildings:  All  buildings  now  or  hereafter
located on the  Installations  Premises and  currently  consisting of three
buildings which, for the purposes of this Lease,  Landlord and Tenant agree
contain, in the aggregate, 36,000 gross square feet of space.

                  Communications Facilities:  The satellite dishes,
antennae, or similar structures or equipment now or hereafter
located on the Installation Premises.

                  Expiration Date:  The ending date of the Term.

                  Installations  Premises:  Certain portions of the Land as
described  and shown on Exhibit C attached  hereto and made a part  hereof,
and containing the Auxiliary Buildings and the Communications Facilities.


<PAGE>
 
                  Land:   Approximately   227  acres  of  land  located  in
Clarksburg, Montgomery County, Maryland, as described or shown on Exhibit A
attached hereto and made a part hereof.

                  Master Lease Property:  The Land, together with all
improvements located thereon, less the Installations Premises and
the Excluded Areas.

                  Main  Building  Area:  The Main  Building and the Parking
Areas,  access drives, and other appurtenant areas serving the Buildings on
such area,  as described  or shown on Exhibit B attached  hereto and made a
part hereof.

                  Parking Areas:  Those certain areas located on the
Installations Premises and designated for use for parking of
motor vehicles as of the Effective Date.

                  Unimproved Area:  The Master Lease Property, less the
Main Building Area.

                  (b) Other  terms  shall have  meanings  ascribed  to such
terms in this Lease and as shown on  Schedule I attached  hereto and made a
part hereof.

                  SECTION 2.        LEASE OF INSTALLATIONS PREMISES

                  Landlord,   for  and  in   consideration  of  the  rents,
covenants and agreements  hereinafter reserved,  mentioned and contained on
the part of Tenant and its  successors  and assigns,  to be paid,  kept and
performed,  has leased, rented, let and demised, and by these presents does
lease,  rent,  let and demise unto Tenant,  and Tenant does hereby take and
hire,   upon  and  subject  to  the  covenants,   agreements,   provisions,
limitations and conditions herein expressed, the Installations Premises.

                  SECTION 3.        TERM

                  (a) The initial term of this Lease (the  "Initial  Term")
shall be for a period of ten (10) years  commencing on the  Effective  Date
and  ending  at  11:59  p.m.  local  time on the day  preceding  the  tenth
anniversary  of the  Effective  Date,  unless  this  Lease  shall be sooner
terminated as hereinafter  provided or as provided by law.  Notwithstanding
the  foregoing,  if the Term ends on any day other than the last day of any
calendar month, the Term shall be extended so that the last day of the Term
is the  last  day of such  calendar  month.  The  Initial  Term,  as may be
extended by exercise of Section 28, may sometimes be collectively  referred
to in this Lease as the "Term".

                  (b) As used in this Lease,  the term  "Lease  Year" means
each  consecutive  period of twelve (12)  calendar  months during the Term,
commencing on the Effective Date. If, however,  the Effective Date is other
than the first day of a calendar month, the first Lease Year shall begin on
the Effective Date and end on


                                                         
<PAGE>
 
the first  anniversary  of the last day of the calendar  month in which the
Effective  Date  falls,  and  each  succeeding  Lease  Year  shall  be each
succeeding  consecutive  period of twelve (12) calendar  months  thereafter
during the Term.

                  SECTION 4.        RENT

                  (a) Tenant covenants and agrees to pay Landlord in lawful
money of the United States, annual base rent for the Installations Premises
("Base Rent") in twelve (12) equal monthly installments,  in advance, on or
before  the first  day of each and  every  month  throughout  the Term,  as
follows:

                  (i) FOUR HUNDRED TWENTY-FIVE  THOUSAND AND NO/100 DOLLARS
($425,000.00) during the first Lease Year.

                  (ii)  FOUR  HUNDRED   THIRTY-SIX   THOUSAND  SIX  HUNDRED
EIGHTY-SEVEN  AND 50/100  DOLLARS  ($436,687.50),  during the second  Lease
Year.

                  (iii)  FOUR  HUNDRED  FORTY-EIGHT  THOUSAND  SIX  HUNDRED
NINETY-SIX AND 41/100 DOLLARS ($448,696.41), during the third Lease Year.

                  (iv) FOUR  HUNDRED  SIXTY-ONE  THOUSAND  THIRTY-FIVE  AND
56/100 DOLLARS ($461,035.56), during the fourth Lease Year.

                  (v) FOUR HUNDRED  SEVENTY-THREE  THOUSAND  SEVEN  HUNDRED
FOURTEEN AND 04/100 DOLLARS ($473,714.04), during the fifth Lease Year.

                  (vi)  FOUR  HUNDRED  EIGHTY-SIX  THOUSAND  SEVEN  HUNDRED
FORTY-ONE AND 18/100 DOLLARS ($486,741.18), during the sixth Lease Year.

                  (vii) FIVE HUNDRED  THOUSAND  ONE-HUNDRED  TWENTY-SIX AND
56/100 DOLLARS ($500,126.56), during the seventh Lease Year.

                  (viii)  FIVE  HUNDRED  THIRTEEN  THOUSAND  EIGHT  HUNDRED
EIGHTY AND 04/00 DOLLARS ($513,880.04), during the eighth Lease Year.

                  (ix) FIVE HUNDRED TWENTY-EIGHT THOUSAND TWELVE AND 10/100
DOLLARS ($528,012.10), during the ninth Lease Year.

                  (x)  FIVE  HUNDRED   FORTY-TWO   THOUSAND   FIVE  HUNDRED
THIRTY-TWO AND 43/100 DOLLARS ($542,532.43), during the tenth Lease Year.

Notwithstanding  the foregoing,  if the Effective Date shall be a day other
than the first day of a calendar  month,  there shall be due and payable on
the Effective  Date, as the  installment  of Base Rent for such  fractional
month,  an amount  determined by dividing the Base Rent for the first Lease
Year by 365 and multiplying the
<PAGE>
 
result by the number of days from the Effective Date through the
end of such month.

                  (b)  Tenant  also   covenants   and  agrees  to  pay,  as
additional rent (the  "Additional  Rent"),  all sums,  Impositions,  costs,
expenses and other  payments  which Tenant in any of the provisions of this
Lease  assumes,  agrees  or is  obligated  to pay,  or which  shall  become
otherwise  due and payable from Tenant to Landlord  under this Lease (other
than  Base  Rent).   Base  Rent  and  Additional   Rent  may  sometimes  be
collectively referred to herein as "Rent".

                  (c) It is the purpose  and intent of Landlord  and Tenant
that,  except as  explicitly  set  forth  herein,  the Base  Rent  shall be
absolutely  net to  Landlord,  so  that  this  Lease  shall  yield,  net to
Landlord, the net annual rent specified in Subsection (a) of this Section 4
in each  Lease  Year  during  the Term and that  all  costs,  expenses  and
obligations  of every kind and nature  whatsoever,  in  connection  with or
relating to the  Installations  Premises  shall be the obligation of Tenant
and shall be paid by Tenant.

                  (d) The Base Rent shall be paid to Landlord promptly when
due without notice or demand therefor, and without any abatement (except as
explicitly  stated to the contrary in Section 8),  deduction or set-off for
any reason whatsoever.

                  (e) No  payment by Tenant or  receipt  or  acceptance  by
Landlord of a lesser  amount  than the  correct  Rent shall be deemed to be
other than a payment on account,  nor shall any endorsement or statement on
any check or any  letter  accompanying  any check or  payment  be deemed an
accord and  satisfaction,  and  Landlord  may accept  such check or payment
without  prejudice to Landlord's right to recover the balance or pursue any
other remedy in this Lease or as provided by law or in equity.

                  (f) If any  of the  Rent  payable  under  the  terms  and
provisions  of this  Lease  shall be or become  uncollectible,  reduced  or
required to be refunded  because of any rent  control or similar act or law
enacted by a valid  governmental  authority,  Tenant  shall enter into such
agreements  and take such other steps that  Landlord may request and as may
be legally  permissible  to permit  Landlord to collect  the maximum  rents
which,  from  time to time  during  the  continuance  of  such  legal  rent
restriction,  may be legally  permissible (and not in excess of the amounts
reserved  therefor  under this Lease).  Upon the  termination of such legal
rent  restriction,  (i) the Rent shall become and  thereafter be payable in
accordance with the amounts reserved herein for the periods  following such
termination, and (ii) Tenant shall promptly pay to Landlord, to the maximum
extent  legally  permissible,  an amount  equal to (a) the Rent which would
have been paid pursuant to this Lease but for such legal rent  restriction,
less (b) the Rent paid by Tenant  during the period  such rent  restriction
was in effect.
<PAGE>
 
                  (g) All Rent and other  payments  required  to be made by
Tenant to Landlord shall be delivered to Landlord by wire transfer pursuant
to the wire transfer instructions as shown on Exhibit E attached hereto and
made a part hereof or to any other single  party that  Landlord may specify
from time to time by written notice given to Tenant.

                  (h)  In  recognition  of  the  extra  costs  to  Landlord
resulting from Tenant's  failure to make timely payment of any  installment
of Base Rent,  if any such  installment  is not paid  within  nine (9) days
after its due date,  the  delinquent  amount  shall be subject to a service
charge of five  percent  (5%) of such  delinquent  amount,  or such  lesser
charge as may be the maximum charge  permitted by law. In addition,  if any
installment  of Base Rent or any other sum due  Landlord  under  this Lease
remains unpaid  seventy-five  (75) days after its due date, the outstanding
amount  shall bear  interest at an annual rate of two percent (2%) over the
"Prime Rate" then prevailing or such lesser rate as may be the maximum rate
permitted by law (the "Stipulated  Rate"), and calculated from the due date
of such sum and  continuing  through the date such sum is paid in full.  As
used in this Lease,  the term "Prime Rate" means the prime rate of interest
for large money center banks as published in the Money Rates section of the
Wall Street  Journal or if the Wall Street  Journal  ceases to publish such
rate, as established  by reference to such other  authority as is generally
accepted in the business  community as a source for  determining the "Prime
Rate".

                  SECTION 5.        USE OF THE INSTALLATIONS PREMISES

                  (a) The  Installations  Premises may be occupied and used
for any  lawful  purpose  and shall not be used for any other  purpose.  In
addition, Tenant shall have easements on, over, across and through the Main
Building Area and the Unimproved  Area for (i) access to the  Installations
Premises via roads  existing in the  Unimproved  Area and the Main Building
Area as of the Effective Date, or as may be relocated as expressly provided
for in  this  Lease,  (ii)  purposes  which  are  incidental  to use of the
Installation Premises, such as use, maintenance, repair, and replacement of
utilities,  storm  drainage  facilities,  and  signage  serving  or used in
connection with the  Installation  Premises,  (iii)  reasonable  recreation
uses,  such  as use of  the  existing  recreational  facilities,  and  (iv)
temporary  activities  and uses that  Tenant  reasonably  deems  desirable.
Notwithstanding  anything to the  contrary  contained  in this Lease,  with
respect to the uses  described  in clauses  (iii) and (iv)  above,  (y) the
Tenant shall ensure that such uses do not interfere  with the  Development,
and (z) no action or omission of Landlord,  or its Agents,  successors  and
assigns that interferes with such uses shall be a default of Landlord under
this Lease.
<PAGE>
 
                  (b)      Tenant further agrees as follows:

                           (i)      Tenant and its Agents shall use the
Installations  Premises  and  conduct  their  business  thereon  in a safe,
careful, reputable and lawful manner.

                           (ii) Tenant shall obtain, or cause to be obtained,
all certificates, licenses and permits necessary for its, or its subtenants',
occupancy, use, operation and maintenance of the Installations Premises. Upon
reasonable advance request by Tenant, Landlord shall reasonably cooperate with
Tenant in Tenant's obtaining such necessary certificates, licenses or permits,
including, without limitation, signing applications for the same within ten (10)
business days after Tenant's request if Landlord's signing is required by
Applicable Law or requested by a governmental authority; provided, that Landlord
shall not be required to incur any out-of-pocket costs to third parties in
connection therewith. Tenant shall promptly reimburse Landlord for any of its
reasonable out-of-pocket costs to third parties for review or advice about such
certificates, licenses or permits.

                           (iii) Tenant shall not commit, nor allow to be
committed,  in, on or about the Installations  Premises,  any act of waste,
including  any act which might  deface,  damage or destroy any  improvement
thereon, or any part thereof. Further, Tenant shall not permit any noise or
odor to be emitted  from the  Installations  Premises  which is unlawful or
which constitutes a legal nuisance.  Notwithstanding the foregoing,  Tenant
shall not have any responsibility  for any waste,  noise, or odor caused by
Landlord or its Agents.

                           (iv)   Tenant shall promptly comply in all material
respects  with all present and future laws,  statutes,  ordinances,  rules,
regulations and orders of any federal, state, municipal or other government
or  agency  thereof  having  jurisdiction  over  and  relating  to the use,
condition and occupancy of the Installations  Premises,  and any covenants,
conditions and restrictions of record existing as of the Effective Date and
governing the Installations Premises (collectively, the "Applicable Laws").
Tenant  acknowledges that the Applicable Laws are of public record and that
Tenant knows the character of its operation on the Installations  Premises.
Tenant  shall  have  sole   responsibility  for  its  compliance  with  the
Applicable  Laws in all material  respects,  and  Tenant's  inability to so
comply   shall  not  be  cause  for  Tenant  to   terminate   this   Lease.
Notwithstanding the foregoing:


                                   (A)  Tenant shall not be required to comply
with any  Applicable  Laws to the extent that  Tenant or the  Installations
Premises are legally "grandfathered" or exempt from the application of such
Applicable  Laws or Tenant may obtain from the  appropriate  authorities  a
waiver or variance with respect to compliance.
<PAGE>
 
                                    (B) Tenant shall not be required to comply
with any legal  requirements in connection with the Installations  Premises
arising out of or relating to the  Development or arising out of other acts
or  omissions  of  Landlord  or  its  Agents  on or  with  respect  to  the
Installations  Premises.  All of  such  requirements  on the  Installations
Premises  shall be  promptly  complied  with by  Landlord  in all  material
respects, at its own expense.

                                    (C) Tenant shall not be obligated to
correct any  violations  of  Applicable  Laws which may exist on the
Installations Premises  as of the  Effective  Date,  except  to the  extent
specifically required to do so by written notice from the governmental  
authority having jurisdiction.

                                    (D)  Tenant shall have the right to contest
by appropriate legal proceedings, conducted diligently and in good faith,
without expense to Landlord,  the validity or application of any Applicable
Laws. If compliance  with the Applicable Law being contested may legally be
delayed  pending  the  prosecution  of the  proceeding,  Tenant  may  delay
compliance until the final determination of the proceeding.  Landlord shall
execute and deliver, within ten (10) business days after request by Tenant,
any appropriate  papers and/or other  instruments  that may be necessary to
permit Tenant to contest the validity or application of the Applicable Law.
Landlord shall otherwise  reasonably  cooperate with Tenant in the contest,
provided  that  Landlord  shall not be required to incur any  out-of-pocket
costs  to  third  parties  in  connection  therewith.  Notwithstanding  the
foregoing,  Tenant  shall  ensure that any such  contest does not cause any
lien to be filed against the Installations Premises or any portion thereof.

                  SECTION 6. DEVELOPMENT; DESIGNATION OF THE EXCLUDED
                                     AREAS

                  (a)  Tenant  acknowledges  that,  among  other  purposes,
Landlord purchased the Land for possible  development and/or sale of all or
portions of the  Unimproved  Area.  Although  Landlord  is not  required to
develop or sell any of the Unimproved  Area,  Landlord is  contemplating  a
"mixed-use" development thereon, consisting of, among other things, uses of
varying densities,  sizes and natures, and infrastructure in order to serve
same (all or any portion thereof, the "Development"). The Development shall
be at Landlord's sole cost.  Tenant  acknowledges  that the Development may
require Landlord to change the zoning  classification  of the Installations
Premises. Tenant covenants and  agrees  that  during  the Term it  shall  not
object  to,  and  shall reasonably cooperate with Landlord with respect to,
Development by Landlord or its  successors  of any of the  Unimproved  Area
and  shall  reasonably cooperate so as to avoid interference with the
Development. Notwithstanding the foregoing:
<PAGE>
 
                           (i)  The Development by Landlord shall not
interfere with Tenant's or its subtenants' use of the
Installations Premises.

                           (ii) No rezoning or other development approvals
sought by Landlord for all or any part of the Installations  Premises shall
prohibit,  restrict,  or make  non-conforming  any of the uses which may be
conducted on the Installations  Premises under the I-3 zoning applicable to
such property as of the Effective Date.

                           (iii)  Landlord acknowledges that the
uninterrupted  operation of the  Communications  Facilities  is of critical
importance  to  Tenant.  Landlord  shall not  oppose  the  installation  or
continued operation of the Communications Facilities.

                           (iv)  Tenant shall not be required to incur any
liability  or  out  of  pocket   expense  to  third  parties  in  providing
cooperation to Landlord or its successors with respect to Development.

                  (b)  Intentionally Omitted.

                  (c)  Intentionally Omitted.

                  (d)  In the event  that  ownership  of any  portion of the
Main Building Area or Unimproved  Area is  transferred to another party (an
"Excluded  Area") and such Excluded  Area contains any road,  utility line,
drainage line, storm water management facility,  sign, or other improvement
or  amenity  then  being used by Tenant in  connection  with the  Auxiliary
Buildings or the Communications Facilities (collectively, "Appurtenances"),
then,  automatically  upon such transfer of the Excluded Area, Tenant shall
be deemed to have  easements  for the  continued  uninterrupted  use of the
Appurtenances  for so long as this Lease  remains in effect.  The easements
provided for in this subsection  shall include the right of Tenant to enter
upon the  Excluded  Area to  inspect,  maintain,  repair,  and  replace the
Appurtenances.  Notwithstanding  the  foregoing,  Landlord may  temporarily
discontinue  any  of the  Appurtenances  for a  period  of  not  more  than
forty-eight   (48)  hours  if  Landlord   provides  Tenant  with  temporary
Appurtenances,  provided such temporary  Appurtenances allow Tenant and its
Agents to use the Installations  Premises without any material diminishment
of  Tenant's  or  its  Agents'  use of the  Installations  Premises  or any
material  interference  with  the  business  operations  of  Tenant  or its
subtenants on the Installations Premises.

                  (e)  Notwithstanding anything to the contrary contained in
this  Lease,  Tenant  shall  not be  required  to pay for any  incremental,
additional or increased cost of Insurance or any increased costs of Care of
the  Installations  Premises which are  attributable  to Development or any
other acts or omissions of
<PAGE>
 
Landlord or its Agents with  respect to the  Installations  Premises or the
Unimproved Area.

                  (f)  In   addition   to  the   easements   for   existing
Appurtenances  provided for in  Subsection  6(d),  Landlord  shall grant to
Tenant, or to any utility company or governmental  authority  designated by
Tenant,   such  other   easements  for  utilities,   drainage,   stormwater
management,  and other  similar  matters  on,  under,  and  across the Main
Building  Area  or  Unimproved  Area  as  may  be  reasonably  required  in
connection with the use or occupancy of the  Installations  Premises and in
accordance  with  this  Lease  ("Additional   Easements").   No  Additional
Easements  shall   materially  and  adversely  affect  the  Development  or
materially  increase  the  cost  of  Development.  Landlord  shall  have  a
reasonable  right of approval of the location of all Additional  Easements.
All Additional  Easements  shall be granted  without charge within ten (10)
business  days  after  written  request  by  Tenant,   accompanied  by  the
instrument to be executed and a plat showing the location of the Additional
Easement.  Landlord  shall  make  good  faith and  commercially  reasonable
efforts to cause its mortgagees to subordinate their liens against the Main
Building Area or Unimproved Area to any Additional Easements.

                  SECTION 7.  TAXES AND IMPOSITIONS

                  (a) Tenant  covenants  and agrees to pay,  not later than
the first day on which any  interest or penalty  will accrue or be assessed
for the non-payment  thereof,  all of the following items  applicable to or
affecting  the  Installations  Premises  or any part  thereof  accruing  or
payable from and after the Effective Date and during the Term or applicable
thereto:  (i) all real estate  taxes and  assessments  (including,  without
limitation,  assessments  for special  business  improvement  or assessment
districts),  (ii) personal  property taxes,  (iii) occupancy and rent taxes
specifically  imposed on tenants in Montgomery  County or  attributable  to
subtenants of Tenant,  (iv) water and sewer rents,  rates and charges,  (v)
vault taxes and charges,  (vi) certificate,  license and permit fees, (vii)
any  taxes,  assessments  or  governmental  levies,  general  and  special,
ordinary and extraordinary, foreseen and unforeseen, of any kind and nature
whatsoever  which at any time prior to or during or  applicable to the Term
or any part thereof may be assessed,  levied,  confirmed,  imposed upon, or
grow or accrue or become due and  payable out of, or charged  with  respect
to, or become a lien on, the Installations Premises or any part thereof, or
the  sidewalks  or  streets  in front  of or  adjoining  the  Installations
Premises, or any vault, passageway or space in, over or under such sidewalk
or street, or any other appurtenances to the Installations Premises, or any
personal  property,  equipment  or  other  facility  used in the  operation
thereof,  or any use or occupation of the  Installations  Premises,  or any
document by which Tenant  creates or transfers an interest or estate in the
Installations Premises, and (vii) any fines or penalties or
<PAGE>
 
similar  governmental  charges  applicable  with  respect  to  any  of  the
foregoing,  together  with  interest  and costs  thereon  (all  such  items
aforesaid   may   sometimes   be   collectively   referred   to  herein  as
"Impositions").

                  (b) If, by law, any  Imposition  imposed during the Term,
which is an assessment not related to general real estate taxes, may at the
option of the  taxpayer be paid in  installments  (whether or not  interest
shall accrue on the unpaid balance of such Imposition), Tenant may exercise
the option to pay the same (and any accrued  interest on the unpaid balance
of such  Imposition)  in  installments  and, in such event,  shall pay such
installments plus interest as may become due during the Term of this Lease;
provided, that all such payments shall be made before any fine, penalty, or
other charge for non-payment of any installment may be added thereto.

                  (c) Any Imposition (including,  without limitation, those
Impositions  which have been converted into installment  payments by Tenant
as referred to in Subsection (b) above)  relating to a period of time which
is partially within the Term and partially beyond the Expiration Date shall
be adjusted  between  Landlord and Tenant as of the Expiration Date so that
Landlord shall pay that portion of such Imposition which is attributable to
any  period of time  after the  Expiration  Date and  Tenant  shall pay the
remainder thereof. This subsection shall survive termination of the Lease.

                  (d)  Notwithstanding  the foregoing,  Tenant shall not be
required to pay municipal, state or federal income, excess profits, capital
levy,  rental  (except  as set forth in clause  (iii) of  Subsection  (a)),
estate,  succession,  inheritance,  transfer,  recordation  (except  to the
extent described in Section 30(v)) or gift taxes of Landlord, any corporate
franchise  tax imposed  upon  Landlord  or any tax  imposed  because of the
nature of the business entity of Landlord;  provided,  however,  that if at
any time  during  the  Term,  the  method  of  taxation  prevailing  at the
Effective  Date shall be altered so that,  in  substitution  for ad valorem
real estate taxes, any new Imposition or charge, or any part thereof, shall
be  measured  by or be based in  whole  or in part  upon the  Installations
Premises and shall be imposed upon Landlord,  then all such new Impositions
or charges, or any part thereof,  shall be deemed to be included within the
term  "Impositions",  and Tenant shall pay and discharge the same as herein
provided in respect of the payment of Impositions.

                  (e) (i) If permitted by  Applicable  Law, and provided no
Event of Default is then in existence,  Tenant shall have the right, at its
own expense, to contest the amount or validity, in whole or in part, of any
Imposition by appropriate  proceedings  diligently conducted in good faith.
If, under  Applicable  Law, the  contested  Imposition  must be paid before
undertaking the contest,  Tenant shall pay such  Imposition  (which payment
may be made under protest, at Tenant's option) or, if permitted by
<PAGE>
 
Landlord and any mortgagee of Landlord (including trustees or beneficiaries
of deeds of trust) ("Mortgagee"),  either deposit with Landlord,  Mortgagee
or the  assessing  body, as Landlord,  Mortgagee or the assessing  body may
require,  an amount sufficient to pay all amounts referred to in Subsection
(ii) below,  or  undertake  such other  method of securing  payment of such
amounts as is satisfactory to Landlord, Mortgagee and the assessing body.

                           (ii)    Upon the termination of any such proceeding,
Tenant shall pay the amount of such  Imposition  or part thereof as finally
determined as due in such  proceedings,  the payment of which may have been
deferred  during the  prosecution  of such  proceedings,  together with any
costs,  fees,  interest,  penalties  or  other  liabilities  in  connection
therewith,  and, upon such payment,  Landlord  shall,  provided an Event of
Default is not then in existence, return or request Mortgagee to return any
amount still on deposit with it or with Mortgagee with respect to such paid
Imposition.  If at any time  during  the  continuance  of such  proceedings
Landlord,  Mortgagee or the assessing body shall deem the amount  deposited
or the undertaking insufficient,  Tenant shall, upon thirty (30) days prior
written  notice,  make an additional  undertaking or deposit with Landlord,
Mortgagee or the assessing  body, as Landlord or Mortgagee  reasonably  may
request,  or as the assessing body may require,  and upon failure of Tenant
to do so, the amount  theretofore  deposited  shall be applied by Landlord,
Mortgagee or the  assessing  body to the payment,  removal and discharge of
such Imposition and the interest and penalties in connection  therewith and
any costs, fees (including, without limitation,  reasonable attorneys' fees
and  disbursements) or other liabilities  accruing in any such proceedings,
and the balance, if any, shall be returned to Tenant, or the deficiency, if
any, shall be paid by Tenant immediately on demand of Landlord or Mortgagee
to  the  taxing  authority  to  which  such  Imposition  is  payable.  This
subsection shall survive termination of this Lease.

                  (f)  Landlord  or  Tenant  may,  if it shall  so  desire,
endeavor  at any  time or  times  to  obtain  a  lowering  of the  assessed
valuation upon the  Installations  Premises,  or any part thereof,  for the
purpose of reducing Impositions thereon, and in such event, the other party
will  reasonably  cooperate in effecting such  reduction,  but shall not be
required to incur any out-of-pocket costs in so cooperating.

                  (g)  Landlord  shall  not  be  required  to  join  in any
proceedings  referred to in Subsection  (e) above unless the  provisions of
any law,  rule or  regulation at the time in effect shall require that such
proceedings  be brought by or in the name of  Landlord  or any owner of the
Installations  Premises,  in  which  event,  Landlord  shall  join  in such
proceedings or permit the same to be brought in its name and shall sign all
documents reasonably necessary to prosecute the proceedings. Landlord shall
not be subject to any liability for the payment of any costs or expenses in
connection with any such proceedings, and Tenant will
<PAGE>
 
indemnify  and save  harmless  Landlord from and against any such costs and
expenses,  including,  but not limited to,  reasonable  attorneys' fees and
disbursements, and from any liability resulting from such proceeding. After
reimbursing  and  indemnifying  Landlord  for the items  referred to in the
preceding sentence,  Tenant shall be entitled to any refund with respect to
any  Imposition  and penalties or interest  thereon which have been paid by
Tenant (whether  directly or through  escrowed  funds),  or which have been
paid by Landlord but  previously  reimbursed in full to Landlord by Tenant.
Tenant's right to the refund shall survive termination of this Lease.

                  (h) The certificate,  advice,  statements, or bill of the
appropriate  official  designated  by law to make or  issue  the same or to
receive  payment of any  Imposition  shall be prima facie evidence that the
Imposition  is due and unpaid at the time of the making or issuance of such
certificate, advice statement or bill.

                  (i)  Tenant  shall  make  all  payments  of   Impositions
directly to the appropriate governmental authorities, and Landlord appoints
Tenant  the  attorney-in-fact  of  Landlord  for the  purpose of making all
payments  to be made by Tenant  pursuant to any of the  provisions  of this
Lease to persons or  entities  other than  Landlord.  In case any person or
entity  to whom any sum is  directly  payable  by  Tenant  under any of the
provisions  of this  Section 7 shall  refuse to accept  payment of such sum
from Tenant,  Tenant shall  thereupon  give written  notice of such fact to
Landlord and shall pay such sum  directly to Landlord  and  Landlord  shall
promptly pay such sum to such person or entity.

                  (j) Tenant shall deliver to Landlord  duplicate  receipts
or photostatic copies thereof, or other evidence reasonably satisfactory to
Landlord  (followed by such duplicate  receipts or copies,  when available)
showing the payment of all Impositions, within ten (10) business days after
the  respective  payments  are  required to be made by Tenant and  Landlord
requests such evidence in writing.

                  (k)  Landlord  shall  furnish  to  Tenant  copies  of all
notices of assessment  and bills  relating to  Impositions  within ten (10)
business days after Landlord receives any of the same from the governmental
authorities.

                  SECTION 8.        UTILITIES

                  (a) Tenant  agrees to pay all  charges  made  against the
Installations   Premises  for  gas,  heat,   water,   electricity,   sewage
disposition,  telephone and all other utilities and services related to the
Installations Premises during the Term (collectively, the "Utilities").

                  (b) Tenant understands,  acknowledges and agrees that any
one or more of the Utilities may be  interrupted or diminished by reason of
causes beyond Landlord's reasonable control; that
<PAGE>
 
Landlord does not represent or warrant the  uninterrupted  avail ability of
the Utilities;  that Tenant shall be solely  responsible  for obtaining and
maintaining the use of the Utilities;  and that,  unless caused by Landlord
or its  Agents,  any such  interruption  or  diminishment  shall not (i) be
deemed  an  eviction  or  disturbance  of  Tenant's  right  to  possession,
occupancy and use of the  Installations  Premises or any part  thereof,  or
(ii) render  Landlord  liable to Tenant in damages by  abatement of Rent or
otherwise,  or relieve  Tenant from the obligation to perform its covenants
under this Lease.  In pursuing  the  Development,  Landlord  shall take and
cause  its  Agents  to take  best  efforts  to avoid  the  interruption  or
diminishment of the Utilities.

                  SECTION 9.        SIGNS

                  (a) Tenant shall not  inscribe,  paint,  affix or display
any sign,  advertisement or notice (collectively "Signs") on any portion of
the  Installations  Premises (or on any interior  portion of the  Auxiliary
Buildings that is visible from the exterior) not presently  located thereon
without the prior written  consent of Landlord,  which consent shall not be
unreasonably withheld or delayed.

                  (b) Tenant shall not  inscribe,  paint,  affix or display
any  Sign on any  portion  of the  Unimproved  Area not  presently  located
thereon without the prior written consent of Landlord,  which consent shall
be in Landlord's sole and absolute discretion.
                  (c)  Despite  the  foregoing,  Tenant  shall not  require
Landlord's  consent to replace any Sign existing as of the  Effective  Date
provided that the dimensions and location of the new Sign are substantially
the same as those of the existing Sign.

                  SECTION 10.       AS-IS CONDITION OF INSTALLATIONS
                                    PREMISES

PRIOR TO THE EFFECTIVE DATE, TENANT OWNED THE LAND FOR APPROXIMATELY THIRTY
(30) YEARS,  DEVELOPED THE IMPROVEMENTS THEREON,  INCLUDING BUT NOT LIMITED
TO THE AUXILIARY BUILDINGS AND COMMUNICATIONS  FACILITIES, AND OCCUPIED THE
AUXILIARY  BUILDINGS.  CONSEQUENTLY,  UPON THE EFFECTIVE DATE, TENANT SHALL
ACCEPT THE INSTALLATIONS  PREMISES IN "AS IS" CONDITION.  TENANT AGREES AND
ACKNOWLEDGES  THAT LANDLORD HAS NOT MADE ANY  REPRESENTATION  RESPECTING OR
ANY WARRANTY  WHATSOEVER,  EXPRESS OR IMPLIED,  REGARDING THE INSTALLATIONS
PREMISES,  INCLUDING,  WITHOUT  LIMITATION,  REPRESENTATIONS  OR WARRANTIES
REGARDING THE PHYSICAL NATURE OR CONDITION OF THE  INSTALLATIONS  PREMISES.
TENANT  ACKNOWLEDGES THAT IT IS COGNIZANT OF AND SATISFIED WITH ALL ASPECTS
OF THE INSTALLATIONS PREMISES, AND THAT AS PROVIDED HEREIN THIS TRANSACTION
IS AN "AS IS" TRANSACTION.
<PAGE>
 
                  SECTION 11.       REPAIRS, MAINTENANCE AND MANAGEMENT

                  (a) Tenant shall,  at its sole expense,  keep,  maintain,
manage and operate (collectively,  "Care" or "Care for" or "Care of" as the
context may require) the Installations Premises in a neat, orderly and safe
condition,  in substantially the same manner as Tenant has been maintaining
the Installations Premises as of the Effective Date, and in compliance with
all Applicable Laws in all material respects. In addition, all repairs made
by Tenant shall be reasonably  suited to accomplish their intended purposes
and shall be in compliance with  Applicable Laws in all material  respects.
Tenant  shall in any event make all repairs  necessary  to avoid  damage or
injury to persons or property. Landlord shall have no obligation whatsoever
to Care  for the  Installations  Premises  except  that  Landlord  shall be
responsible  for  any  repairs  necessitated  by  Landlord  or its  Agents.
Further, Tenant, while it was owner of the Property, recorded a Declaration
of Easements,  Covenants,  and Restrictions (the  "Declaration").  Landlord
hereby  delegates to Tenant,  and Tenant hereby accepts from Landlord,  the
maintenance  and  repair  obligations   applicable  to  the  owner  of  the
Installations Premises and described in Section 6 of the Declaration.

                  (b) If any  dispute  shall  arise  between  Landlord  and
Tenant as to the standard of Care required under  Subsection (a) above, the
matter shall be resolved by binding arbitration in accordance with the then
prevailing  Commercial   Arbitration  Rules  of  the  American  Arbitration
Association  (the "AAA").  Upon demand for  arbitration  by either party in
accordance  with  such  rules,  the  matter  shall be  decided  by a single
arbitrator in Montgomery County, Maryland,  selected in accordance with the
prevailing Commercial  Arbitration Rules of the AAA. In deciding any matter
relating to the  Installations  Premises,  the  arbitrator  shall take into
account  the age and  character  of the  improvements  on the  Installation
Premises,  the  standards  of Care set forth in this  Section  11,  and the
remaining Term of this Lease.  The  arbitrator  shall hold a hearing on the
matter within  forty-five (45) days after he or she is appointed.  At least
twenty (20) days before the  hearing,  each party shall submit to the other
party a written  statement of its case,  copies of all documents upon which
it intends to rely at the hearing,  and a list of the  witnesses it intends
to call to testify at the hearing.  The hearing  shall be concluded  within
fifteen (15) days after the initial  hearing date and the arbitrator  shall
decide the matter within  fifteen (15) days after the hearing is concluded.
The arbitrator  shall render his or her decision in writing,  setting forth
the reasons for the  decision.  Each party shall bear its own costs related
to the arbitration,  except that the parties shall share equally all filing
fees and other costs imposed by the AAA in connection  with the arbitration
and the fees of the  arbitrator.  The decision of the  arbitrator  shall be
final and non-appealable and judgment on the decision may be entered in any
court of competent jurisdiction.
<PAGE>
 
                  (c) Unless required by Applicable Laws,  Tenant shall not
be required to (i) improve, upgrade, re-model, retrofit, or renovate all or
any part of the Installations  Premises or (ii) subject to Subsection 11(a)
(excluding the requirement that Care be in substantially the same manner as
Tenant has been maintaining the Installations  Premises as of the Effective
Date),  make any  replacement or major repair of any component,  element or
system of the Installations Premises.

                  (d)  Landlord  agrees that during the Term,  Tenant shall
have the right,  after  providing  prior  written  notice to  Landlord,  to
enforce any rights of Landlord  under  applicable  warranties,  guarantees,
licenses and permits  applicable to the  Installations  Premises.  Landlord
shall sign such documents and otherwise reasonably cooperate with Tenant to
facilitate such  enforcement,  provided that Landlord shall not be required
to incur any out of pocket expense to third parties in so doing.

                  SECTION 12.       ACCESS TO INSTALLATIONS PREMISES

                  Tenant  acknowledges  that  Landlord  has  a  significant
economic  interest in the Care of the safety and  condition  of persons and
property located on and near the Installations  Premises and that Landlord,
pursuant  thereto,   has  a  need,  from  time  to  time,  to  inspect  the
Installations  Premises to insure Tenant's conformity with the covenants of
this Lease. Tenant,  therefore,  hereby authorizes Landlord and any parties
authorized  by Landlord to perform such  inspections  of the  Installations
Premises as Landlord  from time to time may  reasonably  deem  appropriate.
Landlord  shall  have  the  right to  enter  any part of the  Installations
Premises at all reasonable times, upon reasonable  advance notice to Tenant
and accompanied by a representative  of Tenant,  for the purposes of making
such  inspections,   showing  the  Installations  Premises  to  prospective
purchasers,  investors,  mortgagees  and tenants,  and making such repairs,
alterations or improvements to the  Installations  Premises as Landlord may
deem necessary or desirable if Tenant fails to properly Care for same after
notice and  opportunity to cure as provided for in Section  21(a).  No such
entry  shall  materially  interfere  with  the  use  and  occupancy  of the
Installations  Premises by Tenant,  its subtenants and licensees.  Landlord
shall  incur no  liability  to Tenant for such entry  except in the case of
death,  bodily injury, or property damage caused by Landlord or its Agents.
Notwithstanding  the foregoing,  Landlord shall have no right to enter upon
those  portions  of  the  Installations   Premises  which  are  secured  or
confidential  areas  pursuant to  Applicable  Laws or  agreements  to which
Tenant is subject ("Restricted Areas"). Further, no person who is a foreign
national may enter into the Auxiliary Buildings or Antenna Ranges on behalf
of  Landlord,  unless  approval of such  person is obtained  from Tenant in
advance.  Such  approval  may be withheld  only to the extent entry by such
person  would  violate  Applicable  Laws or  agreements  to which Tenant is
subject.

 
<PAGE>
 
                  SECTION 13.       ALTERATIONS AND PERSONAL PROPERTY

                  (a) Tenant,  at its sole  expense and without  Landlord's
approval,  shall  have  the  right  to  make  any  alterations,  additions,
installations or other  improvements  ("Alterations")  to the Installations
Premises,  including,  but  not  limited  to,  constructing  or  installing
additional  Auxiliary  Buildings  and  Communications   Facilities  on  the
Installations  Premises.  In  addition,  Tenant,  at its sole  expense  and
without Landlord's  approval,  may remove or demolish all or any portion of
the  Auxiliary  Buildings  or  Communications   Facilities.  All  buildings
constructed on the Installations Premises after the Effective Date shall be
of a similar or better quality of construction  as the Auxiliary  Buildings
located on the Installations Premises as of the Effective Date.

                  (b) Any  Alteration  shall be  subject,  however,  in all
cases to the following:

                           (i)   All Alterations shall be made at the sole
cost and  expense  of Tenant  and in a good and  workmanlike  manner and in
compliance with all Applicable Laws in all material respects.

                           (ii)  The Installations Premises at all times shall
be kept by Tenant free of liens for labor and materials supplied or claimed
to have been supplied to the Installations  Premises in connection with the
Alterations.

                           (iii) Notice is hereby given that Landlord shall
not be  liable  for any  labor or  materials  furnished  to or for  Tenant.
Furthermore,  notice is  hereby  given to Tenant  and  Tenant's  mechanics,
laborers and materialmen with respect to the Installations Premises that no
mechanic's,  materialman's  or laborer's lien shall attach to or affect the
reversion  or  other  interest  of  Landlord  in  or to  the  Installations
Premises.

                           (iv)  Worker's compensation, builder's risk and
general  liability  insurance with respect to the Alteration as required by
Section 14 shall be maintained by Tenant.

                  (c) All Communication  Facilities and personal  property,
including,  but not limited to,  trade  fixtures,  furniture,  furnishings,
telephone  switching  equipment,  generators and uninterrupted power supply
equipment,   Restricted   Property   and  moveable   equipment   ("Tenant's
Property"), upon or in the Installations Premises shall remain the property
of Tenant or its  Agents,  as the case may be,  or  remain  under  Tenant's
control, and shall be removed by Tenant, or caused to be removed by Tenant,
at its sole cost and expense,  upon  termination of this Lease or surrender
by Tenant of the  Installations  Premises to Landlord;  provided,  however,
that  Tenant  shall not be required  to remove the  footings,  foundations,
concrete bases or underground bases, or underground cabling or conduits and
such items shall become
<PAGE>
 
the property of Landlord upon the expiration or earlier termination of this
Lease. (The term "Tenant's  Property" does not include Fixtures and Limited
Personal Property as defined in the Purchase and Sale Agreement.)  Further,
Tenant  shall  not be  required  to  remove,  or cause to be  removed,  the
property  of  International   Telecommunications   Satellite   Organization
("Intelsat") in the portion of the Installations Premises described in that
certain  Agreement of Lease between  Tenant and Intelsat  dated October 25,
1990. If Tenant's  removal of Tenant's  Property  shall create an unsafe or
unsightly condition, Tenant shall repair the condition at its sole cost and
expense, reasonable wear and tear excepted, but such obligation shall in no
event be deemed to  require  Tenant to remove  the items  which  Tenant may
leave on the Installations Premises pursuant to the preceding provisions of
this  Subsection  (c). If Tenant  fails to so remove and  repair,  Landlord
shall have the right to remove the Tenant's  Property and to dispose of the
same and to repair the  Installations  Premises without  accountability  to
Tenant,  and at the sole  cost  and  expense  of  Tenant.  The  "Restricted
Property" shall mean all personal property,  including,  but not limited to
documents  and  equipment,  which  are  required  to  be  secured  or  kept
confidential  pursuant to Applicable  Laws or agreements to which Tenant is
subject.  The Restricted Property shall at all times, both during and after
the Term, be the sole responsibility of Tenant. Tenant covenants and agrees
that no  Restricted  Property  shall be left in or upon  the  Installations
Premises  after  termination  of this Lease or  surrender  by Tenant of the
Installations  Premises  to  Landlord.   Upon  the  expiration  or  earlier
termination of this Lease all right,  title and interest to any underground
storage tanks located in the  Installations  Premises  shall  automatically
convey to Landlord  without the  requirement  that either party execute any
other  documents  to  effectuate  the  conveyance  and shall become part of
Landlord's property.

                   SECTION 14.      INSURANCE

                  (a) At all times during the Term, Tenant, at its own cost
and  expense,  shall carry and maintain  the  insurance  coverage set forth
below (the "Insurance"):

                  (i)  Hazard insurance covering the Installations
Premises (including,  without limitation,  all Alterations now or hereafter
made to the  Installations  Premises) under an "All Risks of Physical Loss"
policy (an "All  Risks  Policy")  written  in an amount  equal to an amount
necessary  to satisfy  Tenant's  obligations  as lessor,  in the event of a
casualty,  under the Existing  Leases or  Subleases  and the cost of debris
removal and the value of grading,  paving and  landscaping  in the event of
damage caused by casualty to improvements covered by such insurance.

                  (ii) Commercial  liability  insurance with respect to the
Installations Premises and the operations related thereto,
<PAGE>
 
whether conducted on or off the Installations  Premises,  against liability
for death, bodily injury, and property damage (the "Liability Policy"). The
Liability  Policy shall be on an occurrence  basis and  specifically  shall
include:

                        (A) Contractual liability to cover Tenant's
obligations to indemnify Landlord as required under this Lease; and

                        (B) Water damage and sprinkler leakage legal liability.

The  Liability  Policy shall be written for a combined  single limit of not
less than Ten Million Dollars ($10,000,000). Such limit shall be subject to
reasonable  increase  from  time to time  (but not  more  than  once  every
twenty-four   (24)  months)  in  accordance  with  the  limits  then  being
customarily  carried  with  respect to  similar  properties  in  Montgomery
County, Maryland ("Comparable Properties"),  or operations similar to those
being  conducted  on the  Installations  Premises.  Tenant may  satisfy the
required coverage limits for the Liability Policy by carrying a combination
of primary and excess liability policies providing aggregate coverage in at
least the limits stated herein for such policy.

                  (b) Tenant further covenants and agrees, at its sole cost
and expense, to procure and maintain or cause to be procured and maintained
at all times all necessary  worker's  compensation  insurance  covering all
persons  employed by Tenant,  Existing  Tenants and Subtenants in and about
the Installations Premises.

                  (c) Tenant further covenants and agrees, at its sole cost
and expense, to procure and maintain or cause to be procured and maintained
at  all  times  Comprehensive  Automobile  Insurance  covering  all  owned,
non-owned,  and hired  automobiles of tenant in limits of not less than One
Million Dollars ($1,000,000).

                  (d) In  addition  to the  insurance  carried  by  Tenant,
during the course of any Alteration or Care work undertaken by a contractor
hired by or for Tenant,  Tenant  shall  require  such  contractor  to carry
public  liability  insurance in limits of not less than Two Million Dollars
($2,000,000).

                  (e)  Tenant  may  at its  option  provide  any  Insurance
coverage under a blanket  insurance  policy instead of a separate policy or
policies,  provided that the certificate or certificates  issued under such
blanket  insurance policy,  and the coverage afforded thereby,  conforms in
all respects to the requirements hereof.

                  (f) Intentionally Omitted.

                  (g) All  Insurance  shall be in such  form  and  shall be
issued by such responsible insurance companies licensed to do
<PAGE>
 
business in the State of Maryland as are  reasonably  approved by Landlord.
Any insurance  company rated by Bests  Insurance  Reports (or any successor
publication of comparable standing) as A-, VIII or better and by Standard &
Poor's (or any successor of  comparable  standing) as "A" or better (or the
equivalent  of such  rating)  shall be  deemed a  responsible  company  and
acceptable to Landlord.  Upon the Effective Date, and thereafter,  not less
than five (5) days prior to the expiration  dates of the expiring  policies
of Insurance originals of replacement policies or renewal certificates,  as
the case may be,  bearing  notations  evidencing the payment of premiums or
accompanied by other evidence  reasonably  satisfactory to Landlord of each
payment,  shall be delivered by Tenant to Landlord ("Insurance Notice"). If
Tenant does not provide  Landlord  with the  Insurance  Notice or if Tenant
lets any Insurance lapse,  Landlord shall have the right, without providing
any notice to Tenant,  to procure  replacement  coverage  that is effective
upon such  lapse and  Tenant  shall  promptly  reimburse  Landlord  for the
reasonable cost thereof.

                  (h)  All  policies  of  Insurance  shall  name  Landlord,
Tenant,  and,  if  requested  by  Landlord in  writing,  any  Mortgagee  as
insureds,  as their  respective  interests  may  appear.  All  policies  of
Insurance other than the Liability Policy shall, if requested in writing by
Landlord,  name the  Mortgagee  as a loss  payee,  as the  interest of such
Mortgagee  may  appear,  but subject to the  provisions  of Section 15. Any
request of coverage as to a Mortgagee  shall set forth the name and address
of the Mortgagee.

                  (i) Tenant shall not violate or permit to be violated any
of the conditions,  provisions or requirements of any Insurance policy, and
Tenant shall  perform,  satisfy and comply with,  or cause to be performed,
satisfied and complied with, the conditions, provisions and requirements of
all Insurance  policies and the companies writing such policies so that, at
all  times,  the  Insurance  shall  be  provided  by  companies  reasonably
acceptable to Landlord, except as otherwise provided in Subsection 14(g).

                  (j) Each policy or certificate of Insurance shall contain
(i) an  agreement  by the insurer  that such policy  shall not be canceled,
modified or denied renewal  without at least thirty (30) days prior written
notice to  Landlord  and any  Mortgagee  named as an insured or loss payee,
except  that if the  reason  for  cancellation  or  denial  of  renewal  is
nonpayment of premiums, the notice will be at least ten (10) days, and (ii)
a waiver of subrogation by the insurer.

                  (k) If by  reason  of  changed  economic  conditions  the
Insurance  amounts  referred  to in  this  Lease  become  inadequate,  upon
Landlord's request, the limits shall be reasonably increased by Tenant from
time to time (but not more often than once every  twenty-four  (24) months)
to meet  the  changed  conditions,  but any  changes  in  limits  shall  be
consistent with what is customary for
<PAGE>
 
Comparable  Properties or for operations  similar to those conducted on the
Installations  Premises.  Upon the reasonable  request of Landlord,  Tenant
shall  procure  and obtain such types of  insurance  in lieu of the current
insurance  then required under this Lease;  provided that such  replacement
coverage is substantially similar in scope and nature as the Insurance then
required  under this Lease and is the type of  insurance  that is customary
for Comparable  Properties or for operations  similar to those conducted on
the Installations  Premises.  Notwithstanding  the foregoing,  in the event
that  Landlord  makes  such  request  during  the term of the policy of the
insurance that is being  replaced,  Tenant shall not be required to procure
replacement  coverage until the scheduled expiration or earlier termination
of such policy;  provided,  however,  in no event shall such period  exceed
twelve (12) months.

                  (l)  Notwithstanding any provisions in this Section 14 or
elsewhere in this Lease to the  contrary,  any  deductible  to the All Risk
Policy shall be deemed an amount covered by Insurance and shall be promptly
paid by Tenant in the event of damage required to be covered by Insurance.

                  SECTION 15.       DAMAGE OR DESTRUCTION

                  (a)  In  case  of  damage  to  or   destruction   of  the
Installations  Premises  or any  part  thereof  by fire or  other  casualty
("Damage"),  Tenant will promptly give written  notice thereof to Landlord.
In the case of Damage,  whether or not covered by  Insurance,  Tenant shall
continue to pay Rent without any  abatement,  deduction or set-off and this
Lease shall not terminate.

                  (b) All insurance proceeds payable for Damage or for loss
or damage to Tenant's  Property  shall be the exclusive  property of and be
paid  directly  to  Tenant.  Subject to  Subsection  11(a)  (excluding  the
requirement  that Care be in  substantially  the same  manner as Tenant has
been  maintaining  the  Installations  Premises as of the Effective  Date),
Tenant shall have no obligation to restore the Installations Premises after
Damage.

                  (c) Tenant hereby  releases  Landlord and Landlord hereby
releases  Tenant from any and all liability for any loss,  damage or injury
to person or  property  occurring  in,  on,  about or to the  Installations
Properties or personal property by reason of fire or other casualty, to the
extent proceeds of Insurance are received for such loss,  damage, or injury
or to the extent such proceeds  should have been received  under  Insurance
required  to be carried  by this  Lease.  Because  the  provisions  of this
Subsection  will preclude the assignment of any claim  mentioned  herein by
way of  subrogation  or  otherwise  to an  insurance  company  or any other
person,  Tenant shall give to each insurance company which has issued to it
one or more  policies  of  insurance,  notice of the  terms of the  release
contained in this Subsection, and have such
<PAGE>
 
insurance  policies  properly  endorsed,  if  necessary,   to  prevent  the
invalidation of insurance  coverages by reason of the release  contained in
this Subsection.


                  SECTION 16.       INDEMNIFICATION

                  (a) Tenant  will  protect,  indemnify  and save  harmless
Landlord from and against all liabilities,  obligations,  claims,  damages,
penalties,   causes  of  action,  costs  and  expenses  (including  without
limitation,  reasonable  attorneys'  fees  and  expenses)  imposed  upon or
incurred by or asserted  against  Land lord by reason of (i) any  accident,
injury to or death of persons or loss of or damage to property occurring on
or about  the  Installations  Premises  or any part  thereof  caused by the
negligence  or  intentional  misconduct  of Tenant or its Agents;  (ii) any
failure on the part of Tenant to perform or comply with any of the terms of
this Lease; or (iii) performance of any labor or services or the furnishing
of any materials or other property in respect of the Installations Premises
or any part thereof at the  direction  of Tenant.  Tenant  hereby  releases
Landlord from any and all liability for the same.

                  (b) Landlord  will  protect,  indemnify and save harmless
Tenant from and  against all  liabilities,  obligations,  claims,  damages,
penalties,   causes  of  action,  costs  and  expenses  (including  without
limitation,  reasonable  attorneys'  fees  and  expenses)  imposed  upon or
incurred  by or  asserted  against  Tenant by  reason of (i) any  accident,
injury to or death of persons or loss of or damage to property occurring on
or about the  Installations  Premises  or any part  thereof,  caused by the
negligence or  intentional  misconduct of Landlord or its Agents;  (ii) any
failure on the part of  Landlord to perform or comply with any of the terms
of this  Lease;  or  (iii)  performance  of any  labor or  services  or the
furnishing  of  any   materials  or  other   property  in  respect  of  the
Installations  Premises or any part  thereof at the  direction of Landlord.
Landlord hereby releases Tenant from any and all liability for the same.

                  (c) The amount which any party (an "Indemnifying  Party")
is or may be required to pay to any other party (an "Indemnitee")  pursuant
to this  Section  16  shall  be  reduced  (including,  without  limitation,
retroactively)  by any  insurance  proceeds  (or the  amount  of  insurance
proceeds  that would have been  recovered  had  insurance  required by this
Lease been obtained) or other amounts actually recovered by or on behalf of
such  Indemnitee,  in reduction of the related loss. If an Indemnitee shall
have received payment (an "Indemnity  Payment") required by this Lease from
an  Indemnifying  Party  in  respect  of any loss  and  shall  subsequently
actually  receive  insurance  proceeds or other  amounts in respect to such
loss, then such Indemnitee shall pay to such Indemnifying Party a sum equal
to the amount of such insurance proceeds or other amounts actually received
(up to but not in excess of the amount of any Indemnity
<PAGE>
 
Payment made hereunder). An insurer who would otherwise be obligated to pay
any claim shall not be relieved of the responsibility with respect thereto,
or, solely by virtue of the  indemnification  provisions  hereof,  have any
subrogation rights with respect thereto, it being expressly  understood and
agreed  no  insurer  or any  other  third  party  shall  be  entitled  to a
"windfall"  (i.e.,  a benefit  they would not be entitled to receive in the
absence of the indemnification provisions) by virtue of the indemnification
provisions hereof.

                  (d) Procedures for  indemnification of Third Party Claims
shall be as follows:

                           (i)      If an Indemnitee shall receive notice or
otherwise  learn  of  the  assertion  by  a  person   (including,   without
limitation, any governmental entity) who is not a party to this Lease (or a
subsidiary an affiliate of either party) of a claim or of the  commencement
by any such person of any action (a "Third  Party  Claim")  with respect to
which an  Indemnifying  Party may be obligated  to provide  indemnification
pursuant  to this  Section  16 or any other  Section  of this  Lease,  such
Indemnitee  shall  give such  Indemnifying  Party  written  notice  thereof
promptly after becoming aware of such Third Party Claim;  provided that the
failure of any  Indemnitee to give notice as provided in this Section 16(d)
shall not  relieve the  Indemnifying  Party of its  obligations  hereunder,
except to the extent that such Indemnifying Party is actually prejudiced by
such  failure to give notice.  Such notice  shall  describe the Third Party
Claim in reasonable detail.

                           (ii) An  Indemnifying  Party may elect to defend
or to seek to settle or compromise,  at such Indemnifying  Party's own expense
and such  Indemnifying  Party's  own  counsel,  any Third Party  Claim,  as
provided hereafter. Within thirty (30) days after receipt of notice from an
Indemnitee in accordance with Subsection 16(d)(i) (or sooner, if the nature
of such Third Party Claim so requires), the Indemnifying Party shall notify
the Indemnitee of its election whether the  Indemnifying  Party will assume
responsibility  for defending such Third Party Claim.  After notice from an
Indemnifying  Party to an  Indemnitee of its election to assume the defense
of a Third Party Claim, such Indemnifying Party shall not be liable to such
Indemnitee  under this Section 16 for any legal or other  expenses  (except
expenses  approved  in  advance  by the  Indemnifying  Party)  subsequently
incurred  by such  Indemnitee  in  connection  with  the  defense  thereof;
provided that if the defendants  with respect to any such Third Party Claim
include both the Indemnifying  Party and one or more Indemnitees and in any
Indemnitee's reasonable judgment a conflict of interest between one or more
of such Indemnitees and such  Indemnifying  Party exists in respect to such
claim,  such Indemnitees shall have the right to employ separate counsel to
represent  such  Indemnitees  and in that  event  the  reasonable  fees and
expenses of such separate  counsel (but not more than one separate  counsel
reasonably satisfactory to the Indemnifying
<PAGE>
 
Party) shall be paid by such Indemnifying  Party. If an Indemnifying  Party
elects not to assume  responsibility  for defending a Third Party Claim, or
fails  to  notify  an  Indemnitee  of its  election  as  provided  in  this
Subsection  16(d)(ii),  such  Indemnitee  may  defend  or,  subject  to the
remainder of this Subsection  16(d)(ii),  seek to compromise or settle such
Third Party Claim without prejudice to such Indemnitee's rights, if any, to
continue to seek indemnification hereunder.  Notwithstanding the foregoing,
neither an  Indemnifying  Party nor an Indemnitee  may settle or compromise
any claim over the objection of the other; provided,  however, that consent
to settlement or compromise shall not be unreasonably  withheld or delayed.
Neither an Indemnifying  Party nor an Indemnitee  shall consent to entry of
any  judgment or enter into any  settlement  of any Third Party Claim which
does not include as an unconditional  term thereof the giving by a claimant
or plaintiff to such Indemnitee,  in the case of a consent or settlement by
an  Indemnifying  Party,  or to the  Indemnifying  Party,  in the case of a
consent or  settlement  by an  Indemnitee,  of a written  release  from all
liability in respect to such Third Party Claim.

                           (iii) If an Indemnifying Party chooses to defend
or to seek to  compromise  or settle any Third  Party  Claim,  the  related
Indemnitee shall make reasonably  available to such Indemnifying  Party any
personnel or any books,  records or other  documents  within its control or
which it otherwise has the ability to make  available that are necessary or
appropriate for such defense,  settlement or compromise of such Third Party
Claims,   subject   to  the   establishment   of   reasonably   appropriate
confidentiality  arrangements  and  arrangements to preserve any applicable
privilege (including, the attorney-client privilege) and shall cooperate in
such defense, compromise or settlement. If an Indemnifying Party chooses to
defend or to seek to  compromise  or  settle  any Third  Party  Claim,  the
related  Indemnitee shall be entitled to attend and participate in any such
proceeding, discussion or negotiation at its own expense.

                           (iv)  Notwithstanding anything else in this
Section 16 to the contrary,  if an Indemnifying  Party notifies the related
Indemnitee  in writing  of such  Indemnifying  Party's  desire to settle or
compromise  a Third  Party  Claim on the  basis  set  forth in such  notice
(provided that such settlement or compromise  includes as an  unconditional
term thereof the giving by the  claimant or plaintiff of a written  release
of the  Indemnitee  from all  liability  in  respect  thereof  and does not
include any  non-monetary  remedy) and provides the  Indemnitee a copy of a
written  proposal of the applicable  claimant to settle on such terms,  and
the Indemnitee  notifies the Indemnifying  Party in writing within ten (10)
business  days of such notice that such  Indemnitee  declines to accept any
such settlement or compromise, such Indemnitee may continue to contest such
Third Party Claim, free of any participation by such Indemnifying Party, at
such  Indemnitee's  sole  expense.  In such event,  the  obligation of such
Indemnifying Party to such Indemnitee with respect to such Third
<PAGE>
 
Party Claim shall be equal to (i) the costs and expenses of such Indemnitee
prior to the date such  Indemnifying  Party notifies such Indemnitee of the
offer to settle or  compromise  (to the extent such costs and  expenses are
otherwise  indemnifiable  hereunder) plus (ii) the lesser of (A) the amount
of any offer of settlement or compromise which such Indemnitee  declined to
accept and (B) the actual out-of-pocket amount such Indemnitee is obligated
to pay subsequent to such date as a result of such Indemnitee's  continuing
to defend such Third Party Claim (including attorneys fees and expenses).

                           (v)  Any claim on account of a loss which does not
result from a Third Party Claim shall be asserted by written  notice  given
by the  Indemnitee to the related  Indemnifying  Party.  Such  Indemnifying
Party  shall  have a period of 30 days  after the  receipt  of such  notice
within  which to  respond  thereto.  If such  Indemnifying  Party  does not
respond within such thirty (30) day period,  such Indemnifying  Party shall
be deemed to have refused to accept responsibility to make payment. If such
Indemnifying  Party does not respond  within such thirty (30) day period or
rejects such claim in whole or in part,  such  Indemnitee  shall follow the
dispute resolution procedures set forth in Subsection 11(c).

                           (vi) In addition to any adjustments required
pursuant to Subsection  16(c), if the amount of any loss shall, at any time
subsequent to the payment  required by this Lease,  be reduced by recovery,
settlement or otherwise,  the amount of such  reduction,  less any expenses
incurred  in  connection  therewith,   shall  promptly  be  repaid  by  the
Indemnitee to the Indemnifying Party.

                           (vii) In the event of payment by an Indemnifying
Party to any  Indemnitee  in  connection  with any Third Party Claim,  such
Indemnifying  Party shall be subrogated to and shall stand in the place and
the place of such Indemnitee as to any events or  circumstances  in respect
of which such Indemnitee may have any right or claim relating to such Third
Party Claim  against any claimant or plaintiff  asserting  such Third Party
Claim or against any other person.  Such  Indemnitee  shall  cooperate with
such Indemnifying Party in a reasonable manner, and at the cost and expense
of such Indemnifying Party, in prosecuting any subrogated right or claim.

                           (vii) If any indemnity payment required to be made
hereunder is denominated  in a currency  other than United States  dollars,
such payment shall be made in United States  dollars and the amount thereof
shall be  computed  using  the  foreign  exchange  rate  for such  currency
determined  as of the date that  notice of the claim with  respect to which
such indemnity payment is made or given by, or on behalf of, the Indemnitee
to the Indemnifying Party.
<PAGE>
 
                  (e) The  provisions  of this Section 16 shall survive any
termination of this Lease.

                  SECTION 17.       CONDEMNATION

                  (a) If any portion of the Installations Premises is taken
or condemned for a public or quasi-public  use or is sold to a governmental
or  quasi-governmental  authority  in lieu of  condemnation  ("Taken"  or a
"Taking",  as the context shall require),  this Lease shall, as to the part
Taken,  terminate  as of the date that title  shall vest in the  condemning
authority and continue in full force and effect as to the remainder. In the
event of such a  Taking,  Rent  shall  not be  adjusted  and  Tenant  shall
continue to pay Base Rent with respect to the portion of the  Installations
Premises  which has been Taken and Landlord shall retain its remedies under
this Lease with respect to Tenant's obligation to pay such Base Rent.

                  (b) Landlord  and Tenant shall  cooperate in applying for
and  obtaining the maximum  payment or award on account of a Taking.  After
deducting all expenses incurred in connection with obtaining the payment or
award (including reasonable attorneys' fees), the net payment or award (the
"Net Award") shall be distributed  as follows.  Tenant shall be entitled to
claim and receive from the Net Award:  (i) all amounts  designated as being
payable for relocation or similar expenses, (ii) the amount attributable to
the fair market value of Tenant's  leasehold interest in the portion of the
Installations  Premises so Taken, (iii) the amount attributable to the fair
market value of all of Tenant's  Property so Taken or damaged by the Taking
and (iv) the amount  attributable to the fair market value of all buildings
and  improvements  so Taken or damaged by the  Taking,  to the extent  that
Tenant  actually  replaces or repairs same.  Landlord  shall be entitled to
claim and  receive  from the Net Award (i) the amount  attributable  to the
fair market value of Landlord's  fee simple  interest,  as such interest is
subject to this  Lease,  in the  portion of the  Installations  Premises so
Taken,  as such  interest  is  subject to this  Lease,  and (ii) the amount
attributable to the fair market value of Landlord's fee simple interest, as
such  interest  is  subject  to this  Lease,  in all of the  buildings  and
improvements  so Taken or damaged by the Taking,  to the extent that Tenant
does not replace or repair same.  Any dispute  between  Landlord and Tenant
with respect to the distribution  and  apportionment of the Net Award under
the foregoing  provisions  shall be decided by arbitration  pursuant to the
provisions of Subsection  11(b),  with the arbitrator to be a disinterested
appraiser  holding the designation  "MAI" or other equivalent  professional
designation  and  having  at least  ten (10)  years  experience  appraising
commercial  properties in Montgomery County,  Maryland.  Any portion of the
Net  Award  remaining  after  distribution  to  Tenant  and  Landlord,   as
aforesaid, shall belong to Landlord.
<PAGE>
 
                  (c)  In  the  event,   however,  that  the  area  of  the
Installations  Premises shown on Exhibit F or any portion thereof is Taken,
Tenant will not be entitled to make any claim to the  condemning  authority
with respect to that Taking,  except for  relocation  expenses and the fair
market value of Tenant's Property so Taken or damaged by the Taking.

                  (d)  Notwithstanding  the  foregoing  provisions  of this
Section 17, in the case of a Taking of the entire  Installations  Premises,
this Lease  shall  terminate  as of the date that  title  shall vest in the
condemning authority.  Further, in the case that the Taking involves such a
material portion of the Installations  Premises that it is not economically
or technologically  practical for Tenant or Subtenants to use the remaining
portion of the Installations Premises for a satellite earth station, Tenant
may terminate this Lease by written notice to Landlord and this Lease shall
terminate as of the date that title shall vest in the condemning authority.
Upon termination under this Subsection 17(d), Rent shall be adjusted to the
date  of  termination  and  Landlord  and  Tenant  shall  have  no  further
obligations  hereunder,  except with respect to any obligations which arose
or  accrued  before  the  termination  of  this  Lease  or  to  the  extent
obligations  are to survive  the  termination  of this  Lease as  otherwise
expressly  provided in this Lease. Any dispute as to the right of Tenant to
terminate  this  Lease  under  this  Subsection  17(d)  shall be decided by
arbitration in accordance with Subsection 11(b).

                  (e) In no event shall  Tenant be obligated to restore the
Auxiliary  Buildings or any other part of the Installations  Premises which
are damaged by a Taking.  If, however,  this Lease does not terminate under
Subsection  17(d),  Tenant  shall  take such  actions  with  respect to any
damaged portion of the Installations  Premises as are reasonably  necessary
to comply with Tenant's obligations of Care under Subsection 11(a).

                  SECTION 18.       LIENS

                  If,  because of any act or  omission  of Tenant or anyone
claiming by,  through,  or under Tenant,  any mechanic's lien or other lien
shall be filed against the  Installations  Premises or any portion thereof,
or against other property of Landlord, whether or not such lien is valid or
enforceable as such, Tenant shall, at its own expense, cause the same to be
discharged  of record within a reasonable  time,  not to exceed thirty (30)
days, after the date of filing thereof, and shall also defend and indemnify
Landlord and any  Mortgagee and hold them harmless from any and all claims,
losses,  damages,  judgments,  settlements,  costs and expenses,  including
reasonable  attorneys' fees,  resulting therefrom or incurred in connection
therewith.  Tenant shall not  mortgage,  pledge,  hypothecate  or assign as
security its interest in the Installations Premises or under this Lease.
<PAGE>
 
                  SECTION 19.       EXISTING SPACE LEASES; ASSIGNMENT AND
                                    SUBLETTING

                  (a) On the Effective Date, the Installations  Premises is
subject to those  certain  leases  listed in Exhibit G attached  hereto and
made a part hereof (the "Existing Space  Leases"),  which were entered into
by  Tenant,  as  lessor  thereunder,  prior  to  closing  under  the  Sales
Agreement. Landlord has not assumed any of Tenant's obligations thereunder.
For so long as this Lease remains in effect, Tenant covenants and agrees to
continue to discharge  all of the lessor's  obligations  under the Existing
Space Leases, whether accrued or accruing before or during the Term. Tenant
shall indemnify,  defend, and hold harmless Landlord against any obligation
of Landlord under the Existing Space Leases arising or accruing  during the
Term,  except to the extent Tenant is unable to perform such obligations as
a result of Landlord's breach of its obligations  under this Lease.  During
the Term, Tenant shall have the right to (i) collect and retain for its own
account  (subject to Subsection (c) below) all rents and other payments due
from tenants under Existing Space Leases  ("Existing  Tenants"),  (ii) hold
and apply any security  deposits of Existing Tenants in accordance with the
Existing Space Leases  (provided,  however,  that Tenant shall deliver such
security  deposits to Landlord at the expiration or earlier  termination of
this Lease to the extent such  security  deposits  have not been applied by
Tenant  pursuant to the applicable  Existing Space Lease or returned to the
applicable  Existing Tenant, and the term of the applicable  Existing Space
Lease extends beyond the Term),  and (iii)  terminate,  modify or otherwise
deal with the  Existing  Space  Leases as Tenant,  in its sole  discretion,
deems appropriate;  provided,  however,  (A) such right shall automatically
end upon the  termination  of this  Lease for any  reason,  (B) none of the
Existing Space Leases shall be modified to provide for a term which extends
beyond the Term,  unless  Landlord gives its prior written  consent to such
extended term,  which consent may be granted or withheld in Landlord's sole
discretion,  (C) each  modification  of an  Existing  Space  Lease shall be
subject and  subordinate to this Lease,  and in the event of the expiration
or termination  of this Lease,  Landlord shall not be required to recognize
such  modification  without its express  written  agreement  to be bound by
same,  which may be given or not in  Landlord's  sole  discretion,  and (D)
Tenant  shall  promptly   provide  to  Landlord  copies  of  all  documents
terminating or modifying any Existing Space Lease.

                  (b)  Tenant may  assign  its  interest  in this Lease (an
"Assignment") or sublet all or any portion of the Installations Premises (a
"Sublease"), without the consent of Landlord. The term of any such Sublease
shall not exceed the Term,  unless Landlord gives its prior written consent
to such  extended  term,  which  consent  may be  granted  or  withheld  in
Landlord's  sole  discretion.  In the event of any  Assignment or Sublease,
Tenant shall  nevertheless at all times remain fully responsible and liable
for the payment of Rent and the performance and observance
<PAGE>
 
of all of Tenant's other  obligations under this Lease. Each Sublease shall
be subject and subordinate to this Lease. If requested by Tenant,  Landlord
shall enter into a nondisturbance agreement with respect to any Sublease on
substantially  the  same  terms  as are  contained  in  the  nondisturbance
agreement  attached  hereto as Exhibit H (the  "Landlord  Approved  SNDA"),
provided  that (i) the Sublease does not, in any material  respect,  impose
greater  obligations  on the  sublandlord  or grant  greater  rights to the
subtenant  than those  existing as of the Effective Date under the Existing
Space  Leases,  (ii) term of the  Sublease  does not  extend  past the Term
(unless  expressly  approved  by  Landlord  as  aforesaid),  and  (iii) the
Sublease (y) is an arms-length transaction and such subtenant was obtained,
and the economic  terms of such Sublease were  negotiated by, a third party
leasing  agent using  marketing  efforts  customarily  used for  Comparable
Properties,  or (z)  requires  the  subtenant to pay basic rent at the then
current  Base Rent rate per  square  foot  under  this Lease and a pro rata
share of  increases  in  operating  expenses,  Impositions  and  insurance.
Landlord  agrees at any time  hereafter,  upon ten (10) business days prior
written  notice,  to  execute  and  deliver,  and  cause its  Mortgagee  to
recognize,  the Landlord Approved SNDA, provided the Landlord Approved SNDA
has been duly executed by Tenant and such subtenant. Promptly upon entering
into any Assignment or Sublease,  Tenant shall provide Landlord with copies
of all documents effecting such Assignment or Sublease.

                  (c) If there is an Event of  Default,  in addition to any
other  remedies  provided  by this  Lease  or by law or in  equity,  at its
option, Landlord may collect directly from any Existing Tenant, Assignee or
lessee under a Sublease  ("Subtenant")  all rent  becoming due to Tenant by
reason of the  applicable  Existing  Lease,  Assignment  or  Sublease.  Any
collection  by Landlord  from the  Existing  Tenant,  Assignee or Subtenant
shall not be construed  to  constitute a novation or release of Tenant from
the  further  performance  of  its  obligations  under  this  Lease  or  an
acceptance of the terms of such Existing Lease, Assignment or Sublease.

                  (d) Any amounts collected by Landlord pursuant to Section
19(c) or otherwise from an Existing Tenant, Assignee or Subtenant which are
applicable to any period  preceding the Expiration Date (had this Lease run
its full  Initial  Term as may have been  extended),  shall be  applied  by
Landlord to the reduction of Tenant's  remaining  liability,  if any, under
this Lease.

                  SECTION 20.       SUBORDINATION OR SUPERIORITY OF LEASE

                  (a) Except as  otherwise  provided in this  Section,  the
rights  and  interest  of Tenant  under this  Lease  shall be  subject  and
subordinate  to any  mortgages  that may be placed  upon the  Installations
Premises  and to any and all  advances  to be made  thereunder,  and to the
interest thereon, and all renewals, replacements,  extensions, bifurcations
and splits thereof,  if the Mortgagee named in said mortgage shall elect to
subject and
<PAGE>
 
subordinate  the rights and interest of Tenant under this Lease to the lien
of its mortgage. Any Mortgagee may elect to give the rights and interest of
Tenant  under this Lease  priority  over the lien of its  mortgage.  In the
event of either such election and upon  notification  by such  Mortgagee to
Tenant to that  effect,  the rights and interest of Tenant under this Lease
shall be deemed to be subordinate to, or to have priority over, as the case
may be, the lien of said mortgage,  whether this Lease is dated prior to or
subsequent to the date of said mortgage without any further action required
by Landlord or Mortgagee;  provided, however, that as a condition precedent
to any  subordination  of  this  Lease,  Landlord  delivers  in  advance  a
non-disturbance  agreement  duly executed by Mortgagee  and  Landlord.  The
non-disturbance  agreement shall be  substantially  in the form attached to
and made a part of this Lease as Exhibit I (the "Tenant  Approved SNDA") or
in a  commercially  reasonable  form and subject to the approval of Tenant,
not to be unreasonably withheld.  Tenant agrees at any time hereafter, upon
ten (10)  business days prior  written  notice,  to execute and deliver the
Tenant Approved SNDA.

                  (b)  Nothing  contained  in this  Lease  shall  limit  or
curtail  Landlord's right to sell,  mortgage or otherwise  transfer its fee
interest  in the  Installations  Premises,  or affect  Landlord's  right to
assign the Rent  payable  under this Lease  either as  collateral  security
under a  mortgage  or  otherwise.  Any such  sale,  mortgage,  transfer  or
assignment shall be binding on Tenant but shall be subject to this Lease.

                  (c) Landlord  acknowledges  that the term of the Intelsat
Lease extends beyond the Expiration Date.

                  SECTION 21.       DEFAULTS AND REMEDIES

                  (a) The  occurrence  of any one or more of the  following
events shall be a default and breach of this Lease by Tenant (collectively,
"Events of Default"):

                           (i)      Tenant shall fail to pay any installment of
Rent when the same shall be due and payable  and fail to cure such  default
within  nine  (9)  days  after  receiving   written  notice  from  Landlord
specifying  the default.  For the purposes of this  Subparagraph  21(a)(i),
Tenant  agrees notice by Mortgagee,  or Landlord's  loan service  provider,
given  according  to the terms of Section  26,  shall be deemed  sufficient
notice.

                           (ii)     Tenant shall fail to perform or observe any
other term,  condition,  covenant or obligation required to be performed or
observed  by it under  this  Lease for a period of thirty  (30) days  after
written notice from Landlord  specifying such default;  provided,  however,
that if the term,  condition,  covenant or  obligation  to be  performed by
Tenant is of such  nature  that the same  cannot  reasonably  be  performed
within such thirty (30) day period,  such  default  shall be deemed to have
been cured if Tenant  commences such  performance  within the 30 day period
and thereafter
<PAGE>
 
diligently  undertakes  to  complete  the cure and in all events  cures the
default within one hundred twenty (120) days of Landlord's notice,  subject
to extension for Unavoidable Delays.

                           (iii) An Event of Default,  as defined  therein,
shall occur under that certain lease agreement, dated of even date herewith,
between Landlord and Tenant with respect to the Master Lease Property (the
"Master Lease").

                           (iv)  Termination or rejection of this Lease
pursuant to Section 22.

                           (v)   Assumption or assignment of this Lease, under
the  conditions  referred  to in Section  22,  unless the  requirements  of
Section 22 applicable to such assumption or assignment are satisfied.

                  (b) Upon the occurrence of any Event of Default, Landlord
shall have the following rights and remedies,  in addition to those allowed
by law or equity,  any one or more of which may be  exercised  concurrently
and without further notice to or demand upon Tenant:

                           (i)      Landlord may re-enter the Installations
Premises  and cure any  default  of Tenant,  in which  event  Tenant  shall
reimburse Landlord as Additional Rent for any reasonable costs and expenses
which  Landlord may incur to cure such default;  and Landlord  shall not be
liable to Tenant for any loss or damage  which Tenant may sustain by reason
of Landlord's action, except loss or damage caused by Landlord's negligence
or intentional misconduct.

                           (ii)     Landlord may terminate this Lease, in which
event:  (A) Tenant shall not  thereafter  be entitled to  possession of the
Installations  Premises and Tenant shall immediately  thereafter surrender,
or cause to be surrendered,  the  Installations  Premises to Landlord;  (B)
Landlord may re-enter the  Installations  Premises and dispossess Tenant by
summary  proceedings,  ejectment or other legal  process and may remove its
effects,  without prejudice to any other remedy which Landlord may have for
possession or  arrearages  in Rent;  and (C) Tenant shall be liable for all
loss or damage which Landlord may sustain by reason of such termination and
re-entry;  and  Landlord  may re-let  all or any part of the  Installations
Premises  for a  term  different  from  that  which  would  otherwise  have
constituted  the  balance  of the  Term  and  for  Rent  and on  terms  and
conditions different from those contained herein, whereupon Tenant shall be
obligated  to pay to  Landlord  the  deficiency,  if any,  between the Rent
provided  for  herein  and  that  provided  for in  any  lease  covering  a
subsequent re-letting of the Installations  Premises,  for the period which
would otherwise have constituted the balance of the Term, together with all
of Landlord's  reasonable costs and expenses of preparing the Installations
Premises  for  re-  letting,   including   all   repairs,   tenant   finish
improvements,  brokers' and  attorneys'  fees, and all loss or damage which
Landlord
<PAGE>
 
may sustain by reason of such re-letting, it being expressly understood and
agreed that the liabilities and remedies  specified above shall survive the
termination of this Lease. Landlord shall make diligent efforts to mitigate
its damages in the event of an Event of Default.

                           (iii) (A) Notwithstanding the termination of this
Lease,  Landlord  may declare all Base Rent which would have been due under
this Lease for the balance of the Term to be  immediately  due and payable.
In that  event,  Tenant  shall be  obligated  to pay an amount in cash that
would be necessary to purchase U.S.  Obligations in such amounts and having
such  maturities  that the principal and interest of such U.S.  Obligations
would be  sufficient  to provide funds as close as possible but in no event
less or later  than the  payments  due under this Lease as Base Rent as and
when such  payments  would be due if no  acceleration  of the Base Rent had
occurred (the "Accelerated  Payment").  U.S. Obligations are obligations or
securities not subject to prepayment,  call or early  redemption  which are
direct obligations of, or obligations fully guaranteed as to timely payment
by, the United States of America or any agency or instrumentality  thereof,
the  obligations  of which are  backed by the full  faith and credit of the
United States of America.

                           (B) Upon receipt of the Accelerated Payment,
Landlord shall use commercially reasonable efforts to lease the portions of
the  Installations  Premises  not  subject  of  other  leases  at the  then
currently  existing fair market rate for  Comparable  Properties.  From and
after the Event of Default all rent and other payments, except for security
deposits,  collected  under leases  entered into after the Event of Default
("Post Default Leases") and under any Existing Space Leases,  Subleases, or
occupancy  or  concession  agreements  in effect as of the Event of Default
shall be placed in a separate escrow account (the "Escrow Account") held by
a mutually  acceptable  escrowee  (the  "Escrowee").  Also,  any refunds of
Impositions  paid by Tenant and received by Landlord shall be placed in the
Escrow  Account.  The Escrow Account shall be interest  bearing and earn at
least a money  market rate of interest.  All  interest  earned shall become
part of the escrow fund and be treated in the same manner as the  principal
in the Escrow  Account.  The Post  Default  Leases and all  Existing  Space
Leases,  Subleases, and occupancy and concession agreements in effect as of
the  Event of  Default  are  collectively  referred  to as the  "Mitigation
Leases".  The funds  contained in the Escrow  Account shall be disbursed in
the following  manner and with the following  priority:  (i) all direct and
reasonable  operating  expenses  ("Operating  Expenses")  paid by  Landlord
relating  to the  Installations  Premises  during  the  "Default  Measuring
Period"  (defined  below) shall be paid to Landlord,  (ii) a management fee
equal to three  percent (3%) of the amount  collected by Landlord  from the
Mitigation  Leases  during the Default  Measuring  Period  shall be paid to
Landlord,  (iii) all  direct and  reasonable  costs of  collection  paid by
Landlord to collect the sums payable under the  Mitigation  Leases shall be
paid to Landlord,  (iv) reasonable and customary brokerage fees, reasonable
attorneys' fees
<PAGE>
 
and all other  reasonable  out of pocket costs paid by Landlord  during the
Default Measuring Period to third parties in connection with the Mitigation
Leases (including the fees of the Escrowee and the Escrow Account) shall be
paid to Landlord, (v) Tenant shall be paid up to the amount that Tenant was
scheduled to pay as Base Rent during the Default Measuring Period, and (vi)
the remainder  shall be shared  equally by Landlord and Tenant.  As used in
this Section,  the term "Default Measuring Period" shall mean (1) as to the
payments  contemplated in (i) through (iv) above,  each consecutive one (1)
month period after the  establishment  of the Escrow Account until the date
the Term would have  expired but for the early  termination  of this Lease,
and  (2) as to the  payments  contemplated  in (v)  and  (vi)  above,  each
consecutive  three (3) month period after the  establishment  of the Escrow
Account  until  the date the Term  would  have  expired  but for the  early
termination of this Lease.  The first Default  Measuring  Period,  however,
shall also  include the period from the date of the Event of Default to the
date the Escrow Account was established.  Escrowee shall make disbursements
to the parties in the priority  described  above on or about the  fifteenth
(15th) day after the end of each Default Measuring Period.  Within ten (10)
days  after  the end of  each  Default  Measuring  Period  relating  to the
payments  contemplated in (i) through (iv) above, Landlord shall furnish to
Escrowee and Tenant a written  statement setting forth in reasonable detail
all amounts paid into the Escrow Account and all amounts for which Landlord
is claiming  payment  with  respect to the  immediately  preceding  Default
Measuring  Period.  The  statement  shall be certified by Landlord as being
accurate  and shall be  accompanied  by  invoices  and other  documentation
reasonably  evidencing  the amounts  claimed for  payment.  Escrowee  shall
withhold from the payments made under (v) and (vi) above  one-fourth of the
reasonably  estimated  real estate taxes and Insurance  premiums  which are
next due  respect to the  Installations  Premises,  less the amounts of any
real estate taxes or  Insurance  premiums  required to be directly  paid by
tenants under the  Mitigation  Leases (the "Tax and Insurance  Holdbacks").
Escrowee shall release the Tax and Insurance Holdbacks to Landlord when and
to the extent that real estate taxes and Insurance  premiums are payable by
Landlord with respect to the  Installations  Premises.  At the time of each
such  disbursement to Landlord,  Escrowee shall also disburse to Tenant the
amount,  if any, by which the Tax and Insurance  Holdbacks held by Escrowee
exceed the tax bill or Insurance  premiums paid with such Tax and Insurance
Holdbacks. Although the last Default Measuring Period shall end on the date
the Initial Term would have expired but for the early  termination  of this
Lease, any amounts  collected by Landlord under the Mitigation Leases after
that date and  attributable to any period which occurred prior to that date
shall be paid  directly by  Landlord to Tenant.  No party shall be paid for
any amount  described in this  Subsection  (B) to the extent such party was
otherwise  reimbursed  for  such  amount,  including,  without  limitation,
previous  payment  by the  Escrowee  or  previous  reimbursement  under the
Mitigation Leases. For the purposes of this Section,  "Operating  Expenses"
excludes  (1) debt  service and other costs of  Landlord's  financing,  (2)
capital expenditures,
<PAGE>
 
except  to  the  extent  that   Landlord  is   obligated  to  make  capital
improvements  under the terms of Existing  Space  Leases and  Subleases  in
effect as of the Event of  Default,  and then only to the  extent  that the
amortized cost of such capital  improvements  is properly  allocable to the
Default   Measuring  Period,   (3)  management  fees,  (4)  overhead,   (5)
depreciation,  (6) accountants' fees, (7) any losses or expenses covered by
Insurance,  whether  or  not  such  Insurance  is in  fact  maintained,  or
compensable by condemnation  proceeds, (8) any amount incurred by reason of
the  negligence or  intentional  misconduct of Landlord or its Agents,  (9)
fines or  penalties,  and (10) any amounts  paid by specific  tenants.  Any
refunds,  discounts,  or  recoupments  of  Operating  Expenses  received by
Landlord  shall be accounted  for by Landlord and credited  back to Tenant.
Tenant, at reasonable times and upon reasonable notice shall have the right
to audit  Landlord's  books and  records  relating to  Operating  Expenses;
provided,  however,  in no event  shall  Landlord  be required to keep such
underlying receipts for Operating Expenses beyond a date which is three (3)
years after Escrowee makes a disbursement for such Operating Expenses.  The
cost of capital expenditures which may be included as Operating Expenses as
provided above shall be amortized over the useful life of each such capital
expenditure as determined for federal income tax purposes.  Notwithstanding
the  foregoing,  Landlord  shall not be entitled to payment from the Escrow
Account for any costs of repairs or maintenance  that Tenant would not have
been obligated to undertake under the standard of Care set forth in Section
11 of this Lease or for any other  Operating  Costs which  Tenant would not
have been  obligated to pay under this lease.  Notwithstanding  anything to
the contrary  contained  herein,  until the expiration of 91 days after the
receipt of the Accelerated Payment, Tenant shall not make any claim against
Landlord that  Landlord has failed to use diligent  efforts to mitigate its
damages  after  the Event of  Default  which  gave rise to the  Accelerated
Payment. This provision shall survive the termination of this Lease.

                           (iv)   Landlord may sue for injunctive relief or to
recover damages for any loss resulting from the breach.

                  (c) Any agreement for an extension of the Term or for any
other  additional  period after the Term shall not thereby prevent Landlord
from  terminating this Lease for any reason specified in this Lease. If any
such right of termination  is exercised by Landlord  during the Term or any
extension  thereof,  Tenant's  right to any extension or additional  period
shall thereby be automatically  canceled.  Any such right of termination of
Landlord contained herein shall continue during the Term and any subsequent
extension hereof.

                  (d) The  failure  or delay by either  party to enforce or
exercise at any time any of the rights or remedies or other  provisions  of
this Lease shall not be  construed to be a waiver  thereof,  nor affect the
validity of any part of this Lease or the right of that party thereafter to
enforce each and every such right or remedy or other provisions.  No waiver
of any default or breach
<PAGE>
 
of this Lease shall be held to be a waiver of any other  default or breach.
No act or  omission  by  Landlord  during  the  Term  shall  be  deemed  an
acceptance of a surrender of the Installations  Premisesand no agreement to
accept  such a  surrender  shall be valid  unless in writing  and signed by
Landlord.

                  (e) If either  party  defaults  under  this Lease and the
other party places the  enforcement of all or any part of this Lease or the
collection of any sum due or to become due under this Lease or the recovery
of  possession of the  Installations  Premises in the hands of an attorney,
and such party prevails in litigation concerning such issue, the defaulting
party  agrees  to  reimburse  the  prevailing   party  for  the  reasonable
attorney's fees incurred thereby.

                  SECTION 22.       BANKRUPTCY OR INSOLVENCY

                  Landlord and Tenant agree that the following  shall apply
in the event of the bankruptcy or insolvency of Tenant:

                  (a) If a petition  is filed by, or an order for relief is
entered  against  Tenant  under  Chapter 7 of the  Bankruptcy  Code and the
trustee of Tenant  elects to assume this Lease for the purpose of assigning
it, such assumption and assignment may be made only if all of the terms and
conditions of Subsections (b) and (d) below are satisfied. To be effective,
an election to assume this Lease must be in writing, addressed to Landlord,
and  all of  the  conditions  herein  stated,  which  Landlord  and  Tenant
acknowledge to be commercially reasonable, must have been satisfied. If the
trustee  fails so to elect to assume  this Lease  within 60 days after such
filing or order or such additional time as the Bankruptcy Court, for cause,
may fix,  this Lease  will be deemed to have been  rejected,  and  Landlord
shall then  immediately  be entitled  to  possession  of the  Installations
Premises  without  further  obligation  to Tenant or the trustee,  and this
Lease shall be terminated.  Landlord's  right to be compensated for damages
in the bankruptcy proceeding, however, shall survive such termination.

                  (b) If Tenant files a petition for  reorganization  under
Chapters 11 or 13 of the  Bankruptcy  Code, or if a proceeding  filed by or
against Tenant under any other chapter of the Bankruptcy  Code is converted
to a  chapter  11 or 13  proceeding  and  Tenant's  trustee  or  Tenant  as
debtor-in-possession  fails to assume  this  Lease  within 60 days from the
date of the filing of such petition or conversion or such  additional  time
as the  Bankruptcy  Court,  for  cause,  may fix,  then the  trustee or the
debtor-in-possession  shall be deemed to have  rejected  this Lease.  To be
effective, any election to assume this Lease must be in writing,  addressed
to Landlord  and, if there has been a default  under the Lease,  all of the
following   conditions,   which  Landlord  and  Tenant  acknowledge  to  be
commercially reasonable, must have been satisfied:
<PAGE>
 
                           (i)      The trustee or the debtor-in-possession has
                                    cured or has provided to Landlord adequate
                                    assurance that:

                                    (A)     It  will   cure  all   monetary
                                            defaults   under   this   Lease
                                            within   the   number  of  days
                                            specified  in Section  21(a)(I)
                                            of this  Lease from the date of
                                            assumption; and

                                    (B)     It will  cure  all  nonmonetary
                                            defaults   under   this   Lease
                                            within   the   number  of  days
                                            specified in Section  21(a)(ii)
                                            of this  Lease from the date of
                                            assumption.

                           (ii)     The trustee or the debtor-in-possession
                                    has   compensated   Landlord,   or  has
                                    provided    Landlord    with   adequate
                                    assurance   that   Landlord   will   be
                                    compensated  promptly for any pecuniary
                                    loss it has  incurred  arising from the
                                    default of Tenant, the trustee,  or the
                                    debtor-in- possession.

                         (iii)      The trustee or the debtor-in-possession
                                    has  provided  Landlord  with  adequate
                                    assurance of the future  performance of
                                    each of Tenant's obligations under this
                                    Lease; provided,
                                    however, that:

                                    (A)     From  and  after  the  date  of
                                            assumption of this Lease, until
                                            the date of the  assignment  of
                                            this  Lease,  it shall  pay all
                                            monetary           obligations,
                                            including,  without limitation,
                                            the  Rent  payable  under  this
                                            Lease,  in advance on each date
                                            that such amounts are payable.

                                    (B)     It  shall  also   deposit  with
                                            Landlord,  as security  for the
                                            timely   payment  of  Rent,  an
                                            amount  equal to three  months'
                                            Base  Rent and  other  monetary
                                            charges   accruing  under  this
                                            Lease;

                                    (C)     If not  otherwise  required  by
                                            the  terms  of this  Lease,  it
                                            shall also pay in  advance,  on
                                            each day  that any  installment
                                            of Base Rent is  payable,  one-
                                            twelfth of Tenant's Imposition,
                                            Insurance and other obligations
                                            under this Lease.

                  (c)  If  the  trustee  or  the  debtor-in-possession  has
assumed this Lease,  pursuant to Subsection (a) or (b) above, and elects to
assign  Tenant's  interest  under this Lease or the estate  created by that
interest to any other person,  such interest or estate may be assigned only
if the intended assignee has provided


 
<PAGE>
 
adequate assurance of future performance of all of the terms,
covenants, and conditions of this Lease.

For the  purposes of this  Subsection  (d),  "adequate  assurance of future
performance" means that Landlord has ascertained that each of the following
condition has been satisfied:

The assignee has submitted a current financial  statement which shows a net
worth and  working  capital  in  amounts  sufficient  to assure  the future
performance by the assignee of Tenant's obligations under this Lease.

                  (d) When, pursuant to the Bankruptcy Code, the trustee or
the  debtor-in-possession  is obligated to pay reasonable use and occupancy
charges  for the use of all or part of the  Installations  Premises,  it is
agreed that such  charges will not be less than the Base Rent as defined in
this Lease,  plus Additional Rent and other monetary  obligations of Tenant
included herein.

                  (e)  Except  to  the  extent  provided  by  law,  neither
Tenant's  interest  in this Lease nor any estate of Tenant  created in this
Lease  shall pass to any  trustee,  receiver,  assignee  for the benefit of
creditors, or any other person or entity, nor otherwise by operation of law
under the laws of any state having  jurisdiction  of the person or property
of Tenant, unless Landlord consents in writing to such transfer. Landlord's
acceptance  of Rent or any  other  payments  from  any  trustee,  receiver,
assignee,  person,  or other entity will not be deemed to have  waived,  or
waive,  either the requirement of Landlord's consent or Landlord's right to
terminate this Lease for any transfer of Tenant's interest under this Lease
without such consent.

                  SECTION 23.       SURRENDER OF INSTALLATIONS PREMISES

                  Upon the expiration or earlier termination of this Lease,
Tenant shall surrender the Installations Premises to Landlord, broom-clean,
in good order,  condition and repair (except for ordinary wear and tear and
conditions  which  existed  on  the  Installations  Premises  prior  to the
Effective  Date and subject to Sections  15 and 17),  free of all  Tenant's
Property  (except as  otherwise  provided  in  Subsection  13(c),  Personal
Property and Restricted  Property (except for Restricted Property belonging
to any  Existing  Tenant or  Subtenant  whose  Existing  Lease or  Sublease
Landlord  has  expressly  agreed  in  writing  may  continue),  and free of
violation of Applicable  Laws in all material  respects  subject to Section
5(b)(iv).  To the extent  Tenant fails to comply with the  requirements  of
this  Section,  Landlord  may  restore the  Installations  Premises to such
condition at Tenant's expense.

                  SECTION 24.       NON-CONSENSUAL HOLDING OVER

                  In  the  event  Tenant   remains  in  possession  of  the
Installations  Premises or any part thereof without the consent of Landlord
after the expiration or earlier termination of this Lease,
<PAGE>
 
Tenant shall be deemed, at Landlord's  election,  to hold the Installations
Premises as a tenant at sufferance subject to all of the terms, conditions,
covenants and  provisions  of this Lease which shall be  applicable  during
such time (the "Holdover  Period"),  except that, for each month during the
Holdover  Period,  Tenant shall pay to Landlord 150% of the sum of the last
current full monthly  installment of Base Rent plus Additional  Rent, which
shall be payable to Landlord  within five (5) business  days of notice from
Landlord.  In addition,  such  election  shall not preclude  Landlord  from
seeking, and shall be cumulative with, any other remedy under this Lease or
granted by law or in equity.  No holding  over by Tenant,  as  described in
this Section 24,  whether  with or without the consent of  Landlord,  shall
operate to extend this Lease.

                  SECTION 25.       QUIET ENJOYMENT

                  If and for so long as Tenant pays the prescribed Rent and
performs  or  observes  all  of  the  terms,   conditions,   covenants  and
obligations  of this Lease  required  to be  performed  or  observed  by it
hereunder, Tenant shall at all times during the Term have the peaceable and
quiet  enjoyment,  possession,  occupancy  and  use  of  the  Installations
Premises without any interference from Landlord, or anyone claiming through
or under  Landlord,  subject to any  matters of record as of the  Effective
Date to which this Lease is subject.

                  SECTION 26.       NOTICES

                  Any notice, demand or request required or permitted to be
given  under  this Lease or by law shall be deemed to have been given if in
writing and delivered addressed to the party who is to receive such notice,
demand or request at the address  set forth below or at such other  address
as  Landlord or Tenant may  specify  from time to time by notice.  Delivery
hereunder  shall be deemed  to  include  pre-paid  courier  delivery  (by a
reputable  courier delivery  service),  pre-paid  overnight  delivery (by a
reputable  overnight delivery  service),  postage and fees paid U.S. Postal
Service  express mail or  certified  mail,  return  receipt  requested,  or
facsimile transmission with electronic  verification during normal business
hours,  if sent to the address of the  parties  designated  hereunder,  and
shall be deemed  received on the next business day such notice is delivered
or  refused  at such  address  except  notices  sent by fax shall be deemed
received upon electronic verification.

         Landlord:        LCOR Incorporated
                          6701 Democracy Boulevard
                          Bethesda, MD  20817
                          Attn: Mr. R. William Hard
                          Facsimile: (301) 897-3713

         with copies to:  Jones, Day, Reavis & Pogue
                          1450 G Street, N.W.
                          Washington, DC 20005-2088
                          Attn: Sigmund T. Weiner, Esq.
                          Facsimile: (202) 737-2832
<PAGE>
 
                          LCOR Incorporated
                          300 Berwyn Park, Suite 104
                          Berwyn, PA 19312
                          Attention: Mr. Peter DiLullo
                          Facsimile: (610) 408-4420

         Tenant:          COMSAT Corporation
                          6560 Rock Spring Drive
                          Bethesda, MD 20817
                          Attention: General Manager Corporate
                              Services
                          Facsimile: (301) 214-7147

         with a copy to:  COMSAT Corporation
                          6560 Rock Spring Drive
                          Bethesda, MD 20817
                          Attention: General Counsel

                          Facsimile: (301) 214-7128

Any copies required to be sent as above provided are for the convenience of
the  parties  and no such copy  shall  constitute  adequate  notice for the
purposes of this Section.

                  SECTION 27.       HAZARDOUS MATERIALS

                  Landlord  and Tenant agree as follows with respect to the
existence or use of "Hazardous Material" on the Installations Premises.

                  (a)  If  the  use,  storage,  handling,   generation,  or
disposal of Hazardous  Material on or in the Installations  Premises during
the  Term  results  in the  release  or  threatened  release  of  Hazardous
Materials  at, on or under  the  Installations  Premises  in  violation  of
Applicable  Law,  or  otherwise  necessitates  investigation  or cleanup of
Hazardous  Material  as  required  under  Applicable  Law   ("Environmental
Conditions"),  Tenant shall  indemnify,  defend and hold Landlord  harmless
from any and all  claims,  judgments,  damages,  penalties,  fines,  costs,
liabilities  or  losses  (including,   without  limitation,  sums  paid  in
settlement of claims,  attorneys' fees, consultant fees and expert fees but
excluding  consequential  damages  and  any  injury  to  the  value  of the
Property,  provided that this clause shall not be construed as reducing the
Remediation  Obligation)  which arise  during or after the Term as a direct
result  thereof.  This  indemnification  of  Landlord  by Tenant  includes,
without  limitation,  reasonable  costs  incurred  in  connection  with any
investigation  of site  conditions  or any  cleanup,  remedial,  removal or
restoration  work  required  by any  federal,  state or local  governmental
agency because of Hazardous  Material present in the soil or groundwater on
or  under  the  Installations  Premises  or  in  any  improvements  on  the
Installations Premises.  This indemnification,  however, shall not apply to
any Environmental Conditions caused by the acts or omissions of
<PAGE>
 
Landlord or its Agents. The indemnification  and hold harmless  obligations
of Tenant under this Section 27 shall survive any termination of this Lease
for a period of twenty-four (24) months after the  termination.  At the end
of the  twenty-four  (24) month  period,  this  indemnification  and all of
Tenant's obligations under this Section shall expire,  except as to matters
specifically  made the subject of a lawsuit filed against Tenant before the
expiration  of the  twenty-four  (24) month  period.  Without  limiting the
foregoing,  if the use,  storage,  handling,  generation,  or  disposal  of
Hazardous  Material  on or in the  Installations  Premises  during the Term
results  in  any  Environmental   Conditions,   then,   provided  that  the
Environmental  Condition is not caused by the acts or omissions of Landlord
or its Agents, Tenant shall promptly take all actions, at its sole expense,
as are necessary to return the Installations  Premises to substantially the
condition  existing  prior to  thereto or to such  other  condition  as may
satisfy  the  applicable   governmental   authorities   (the   "Remediation
Obligation").  Landlord's approval of such actions shall first be obtained,
which approval shall not be unreasonably withheld.  Nothing in this Section
shall be deemed to prohibit or limit any action by Tenant against any party
or parties responsible for the contamination.

                  (b) Tenant  covenants  and agrees that during the Term it
shall  continue  implementation  of the  Operations  and  Maintenance  Plan
described in Exhibit J attached  hereto and made a part hereof at all times
in compliance with Applicable Laws in all material respects.

                  (c) Landlord shall have the right,  at any time, to cause
the groundwater,  soil,  improvements and air at the Installations Premises
to be investigated to detect the presence of Hazardous  Material during the
Term, including,  but not limited to, the installation of testing wells and
other  devices  in  locations  selected  by  Landlord  at  Landlord's  sole
discretion. Landlord shall supply Tenant with copies of final investigation
reports. The cost of such investigations and of the maintenance, repair and
replacement  of such  wells and other  devices  shall be fully  paid for by
Landlord,  unless Landlord's investigations reveal Environmental Conditions
which Tenant is obligated to remediate  under this Section.  In that event,
Tenant,   within   thirty  (30)  days  after   receiving  a  copy  of  such
investigation  report and a statement of charges from  Landlord,  shall pay
for the cost of the investigation.  Any dispute under this Subsection shall
be  resolved  under the  arbitration  proceedings  set forth in  Subsection
11(b).

                  (d) As used herein,  the term "Hazardous  Material" means
any  hazardous  or toxic  substance,  material or waste which is or becomes
regulated by any local governmental authority, the State of Maryland or the
United  States  Government  or other  Applicable  Law. The term  "Hazardous
Material" includes,  without limitation, any material or substance which is
(i)  designated as a "hazardous  substance"  pursuant to Section 307 of the
Federal  Water  Pollution  Control Act, 33 U.S.C.  Section 1251 et seq. (33
U.S.C.  Section  1317),  (ii)  defined as a "hazardous  waste"  pursuant to
Section 3001
<PAGE>
 
of the Federal Solid Waste Disposal Act, 42 U.S.C. Section 6901 et
seq. (42 U.S.C. Section 6921), or (iii) defined as a "hazardous
substance" pursuant to Section 101 of the Comprehensive
Environmental Response, Compensation and Liability Act, 42 U.S.C.
Section 9601 et seq. (42 U.S.C. Section 9601), or (iv) petroleum,
petroleum product, polychlorinated biphenyls or urea formaldehyde.

                  (e) Within 30 days of the  Expiration  Date, if requested
by Landlord, Tenant shall remove all fuel oil and other liquid contents and
Hazardous  Materials  (collectively,   the  "Contents")  from  all  now  or
hereafter  active  underground  storage tanks located on the  Installations
Premises and dispose of such contents off of the Installations Premises and
in  accordance  with  Applicable  Laws.  Tenant  shall not be  obligated to
remove, close or take any other action to de-commission the tanks during or
after the Term.  If,  however,  during  the Term  governmental  authorities
require such removal,  closure or other action and the  requirement  is not
prompted by Landlord's request to remove the Contents or any Development by
Landlord or its Agents,  Tenant shall  comply with such request  subject to
Subsection 5(b)(iv)(d).

                  (f)  Notwithstanding  anything  contained  in this Lease,
Tenant shall have no obligation or liability to Landlord with respect to:

                           (i)   Any Hazardous Material which may exist on the
Installations  Premises as of the Effective Date, except to the extent that
Tenant is  specifically  required to take action  regarding  such Hazardous
Material by the governmental authority having jurisdiction.

                           (ii)  Hazardous Material that migrates, flows,
percolates,  diffuses or in any way moves on to or under the  Installations
Premises from sources outside the Installations Premises.

                  SECTION 28.       RIGHT TO RENEW TERM

                  (a)  Provided  that this  Lease is then in full force and
effect,  and  provided  that no Event of Default  exists at the time of the
Renewal Notice or the date of  commencement  of the Renewal Term,  Landlord
hereby grants to the Tenant an option (the  "Renewal  Option") to renew the
Initial Term of this Lease on the same terms,  conditions and provisions as
contained in this Lease, except as noted herein, for a period of five years
after the Expiration Date of the Initial Term (the "Renewal  Term"),  which
Renewal Option period shall, except as provided below, commence immediately
following the expiration of the Initial Term and end at 11:59 p.m.
of the fifth anniversary of such date.

                  (b) The Renewal Option shall be exercised,  if at all, by
written  notice  (the  "Renewal  Notice")  from  Tenant to  Landlord of its
election,  said notice to be given no later than the  eighteen  (18) months
prior to the Expiration Date of the Initial Term. If


    
<PAGE>
 
the  Renewal  Notice  is not so given by Tenant to  Landlord,  the  Renewal
Option shall be deemed waived.

                  (c) The  Renewal  Term  shall  be upon  the  same  terms,
covenants and conditions as provided in this Lease except as follows:

                           (i)  Tenant shall not have any further right to
extend the Term or holdover after the end of the Term.

                           (ii) The annual Base Rent for the first year of the
Renewal  Term  shall be equal to  102.75%  of the Base  Rent rate in effect
under this Lease immediately prior to commencement of the Renewal Term.

                          (iii) The annual  Base Rent  shall be  increased
during the Renewal Term by 2.75% per year on a cumulative compounded
basis.

                  SECTION 29.       SECURITY DEPOSIT

                  If at any time  during  the Term,  the  credit  rating of
Tenant's  corporate  debt drops below BBB as rated by Standard & Poor's (or
the  equivalent  rating by any other national  rating agency  designated by
Landlord),  upon  notice from  Landlord,  Tenant  shall  deposit a sum with
Landlord  equal to one month's  installment of the then  applicable  annual
Base Rent  ("Security  Deposit"),  as  security  for the full and  faithful
performance by Tenant, of each and every term,  covenant,  and condition of
this Lease.  If there an event of Default,  Landlord  may use the  Security
Deposit as payment of any Rent or other payment due from Tenant to Landlord
or to otherwise  cure any default of Tenant  hereunder.  To the extent that
any of the Security Deposit is used for this purpose, Tenant shall pay such
amount to Landlord  along with the next  month's Rent in order to replenish
the Security  Deposit to the original  amount stated  herein.  The Security
Deposit shall be returned to Tenant within 30 days of the  Expiration  Date
or earlier  termination of this Lease to the extent that such amount is not
depleted in order to remedy any default by Tenant hereunder.

                  SECTION 30.       MISCELLANEOUS GENERAL PROVISIONS

                  (a) Payments Deemed Rent. Any amounts of money to be paid
by Tenant to Landlord pursuant to the provisions of this Lease,  whether or
not such payments are  denominated  Rent or Additional  Rent and whether or
not  they  are to be  periodic  or  recurring,  shall  be  deemed  Rent  or
Additional  Rent for purposes of this Lease;  and any failure to pay any of
same shall  entitle  Landlord  to exercise  all of the rights and  remedies
afforded  hereby or by law or in equity for the collection and  enforcement
of Tenant's  obligation  to pay Rent.  Tenant's  obligation to pay any such
Rent or  Additional  Rent  pursuant to the  provisions  of this Lease shall
survive the expiration or other termination of this Lease and the surrender
of possession of the Master Lease Property.
<PAGE>
 
                  (b)  Interest  on  Deposits.  Any amount  deposited  with
Landlord under this Lease shall be held by Landlord in a federally insured,
interest bearing account.  Any interest earned on such deposit shall accrue
to Tenant and shall be transferred to Tenant  promptly after the Expiration
Date or such earlier time as may be specified in this Lease unless Landlord
is required by  Applicable  Laws to return such  interest to Tenant  sooner
than stated  herein.  Any amount  deposited with Mortgagee by Tenant (or by
Landlord  on  Tenant's  behalf)  shall  be held by  Mortgagee  pursuant  to
Applicable Laws and pursuant to the security documents between Landlord and
Mortgagee.  No interest shall accrue unless  required by Applicable Laws or
such security documents.  Notwithstanding the foregoing, any amounts placed
in the Escrow  Account  shall be governed by the  provisions  of Subsection
21(b)(iii)(B).

                  (c)   Landlord Cross Default.  Any default by Landlord
under the Master Lease shall be a default by Landlord under this
Lease.

                  (d)  Estoppel  Letters.  Tenant  shall,  within  ten (10)
business days following written request from Landlord, execute, acknowledge
and  deliver to Landlord or to any then  existing  or  prospective  lender,
investor or purchaser,  with respect to the  Installations  Premises or any
part thereof,  designated by Landlord,  a written statement  certifying (i)
that  this  Lease is in full  force  and  effect  (if such is the case) and
unmodified (or, if modified, stating the nature of such modification), (ii)
the date to which Rent has been paid, (iii) that there are not, to Tenant's
actual knowledge, any uncured defaults by Landlord or Tenant (or specifying
such defaults if any are claimed),  and (iv) such other matters as Landlord
may reasonably  request.  Any such statement may be relied upon by any such
then existing or prospective lender, investor or purchaser. If Tenant fails
to  deliver  such  statement  within  the 10  business  day  period  and if
following the  expiration of that period  Landlord  gives a second  written
request for the statement and Tenant fails to deliver the statement  within
5 business  days after the second  request,  Tenant shall  conclusively  be
deemed to have  responded  that this  Lease is in full force and effect and
unmodified and that there are no uncured defaults in Landlord's performance
hereunder.

                  (e) Brokers.  Each party  represents  and warrants to the
other that no broker  procured this Lease on its behalf and that such party
had no conversations or negotiations with any broker concerning the leasing
of the  Installations  Premises,  other  than  Barnes,  Morris,  Pardoe and
Foster, which firm is receiving a commission from Tenant in connection with
the Purchase  and Sale  Agreement  and is not  entitled to a commission  in
connection  with this Lease.  Each party shall  indemnify the other against
liability in connection with a breach of its representation and warranty in
this  Subsection  and in  connection  with any  claim  for a  brokerage  or
finder's  commission or fee arising out of its acts.  This  indemnification
shall survive any termination of this Lease.
<PAGE>
 
                  (f) Applicable Law. This Lease and all matters  pertinent
thereto shall be construed and enforced in accordance  with the  Applicable
Laws of the State of Maryland, excluding choice of laws principles.

                  (g) Entire Agreement.  This Lease, including all exhibits
hereto,  constitutes the entire  agreement  between the parties hereto with
respect  to the  leasing  of the  Installations  Premises  and  may  not be
modified except by an instrument in writing executed by the parties hereto.

                  (h) Binding Effect.  This Lease and the respective rights
and  obligations of the parties hereto shall inure to the benefit of and be
binding upon the  successors  and assigns of the parties  hereto as well as
the parties themselves; subject, however, to Subsection (o) below.

                  (i) Survival. All provisions of this Lease which by their
express terms survive  termination  of this Lease or which by the operation
of their terms are  intended to be  performed,  in whole or in part,  after
termination of this Lease, shall survive any termination of this Lease.

                  (j) Severability. If any provision of this Lease shall be
held to be invalid,  void or unenforceable,  such provision shall be deemed
reformed  to be valid,  in effect  and  enforceable,  and to be as close in
meaning  and  intent as the  defective  provision  and still the  remaining
provisions  hereof  shall not be affected or impaired,  and such  remaining
provisions shall remain in full force and effect.

                  (k)  Headings,  Gender,  etc. As used in this Lease,  the
word "person" shall mean and include,  where  appropriate,  an indivi dual,
corporation,  partnership or other entity;  the plural shall be substituted
for the singular,  and the singular for the plural, where appropriate,  and
words of any gender shall include any other gender. The topical headings of
the  several  paragraphs  of this  Lease are  inserted  only as a matter of
convenience and reference, and do not affect, define, limit or describe the
scope or intent of this Lease.  References  in this Lease to  Sections  and
Subsections are references to Sections and Subsections of this Lease.

                  (l) Waiver of Jury. To the extent permitted by Applicable
Laws,  each of Landlord and Tenant hereby waives any right it may have to a
jury  trial  in  the  event  of  litigation  between  Landlord  and  Tenant
pertaining to this Lease.

                  (m) Landlord's Right to Cure. Landlord may, but shall not
be obligated to, cure any default by Tenant,  specifically  including,  but
not by way of  limitation,  Tenant's  failure  to pay  Impositions,  obtain
Insurance,  Care for the  Installations  Premises,  or satisfy lien claims,
after complying with any applicable notice and cure provisions  established
under this Lease;  and whenever  Landlord so elects,  all reasonable out of
pocket costs and expenses
<PAGE>
 
paid by Landlord in curing such  default,  including,  without  limitation,
reasonable  attorneys'  fees,  shall  be  Additional  Rent  due on the next
scheduled Rent payment date.

                  (n)  Relationship of Parties.  Nothing  contained  herein
shall be deemed or construed by the parties hereto, nor by any third party,
as creating the  relationship of principal and agent or of partnership,  or
of joint venture by the parties hereto, it being understood and agreed that
no  provision  contained  in this Lease nor any act of the  parties  hereto
shall be deemed to create any  relationship  other than the relationship of
Landlord and Tenant.

                  (o) Landlord Means Owner.  The term "Landlord" as used in
this lease,  so far as covenants or obligations on the part of Landlord are
concerned, shall be limited to mean and include only the owner or owners at
the time in question of the Installations Premises and, in the event of any
transfer or  transfers of the title to all of the  Installations  Premises,
Landlord  herein  named  (and  in  case  of  any  subsequent   transfer  or
conveyances,  the then grantor) shall be automatically  freed and relieved,
from and after the date of such transfer or conveyance, of all liability as
respects the  performance  of any covenants or  obligations  on the part of
Landlord  contained in this Lease  thereafter to be performed  (but not any
liabilities accrued prior to the date of transfer); provided that any funds
in the  hands  of such  Landlord  or the then  grantor  at the time of such
transfer,  in which  Tenant has an  interest,  shall be turned  over to the
grantee,  and any amount  then due and payable to Tenant by Landlord or the
then grantor under any  provisions  of this Lease,  shall be paid to Tenant
and  further  provided  that the  transferee  assumes in writing all of the
covenants  and  obligations  of Landlord to observed  and  performed on and
after the date of transfer.

                  (p) References to Size.  Landlord and Tenant  acknowledge
and agree that any  references  in this Lease to the size of the  Property,
the  Auxiliary  Building  Areas,  the  Auxiliary  Buildings  or any portion
thereof are for convenience  only and regardless of whether the actual size
of such areas is greater or less than the size  stated in this  Lease,  all
obligations of the parties  hereunder,  including without  limitation,  the
obligation  to pay Rent shall  remain the same and shall not be affected by
any errors in references to size.

                  (q) Unavoidable  Delays.  For purposes of this Lease, the
term  "Unavoidable  Delays" shall mean delays caused by strikes,  lockouts,
acts  of  God,  inability  to  obtain  labor  or  materials,   governmental
restrictions or inaction,  enemy action,  civil commotion,  fire, terrorist
action, epidemic, public utility failure, unavoidable casualty,  moratorium
or similar laws prohibiting  performance,  severe weather conditions or any
other  similar  matter  which  shall be beyond  the  reasonable  control of
Landlord or Tenant,  as the case way be; but the lack or  insufficiency  of
funds shall not constitute an Unavoidable Delay.
<PAGE>
 
                  (r) Landlord's Approvals.  Wherever Landlord's consent or
approval  are  required  under  this  Lease,   Landlord  shall  approve  or
disapprove  the matter within ten (10) business days after Tenant  requests
the  consent or approval  in  writing.  If Landlord  fails to do so and if,
following the expiration of the ten (10) business day period,  Tenant gives
a second written  request for the consent or approval and Landlord fails to
approve or  disapprove  the matter  within five (5) business days after the
second request,  Landlord shall conclusively be deemed to have consented to
or approved the matter, as the case may be.

                  (s) Rate of  Interest.  If any amount owed by Landlord to
Tenant under this Lease remains  unpaid after such amount is due and notice
thereof  has been given to  Landlord,  the  outstanding  amount  shall bear
interest at the  Stipulated  Rate from the date such amount is due and such
notice is given to the date such amount is paid.

                  (t)  Cooperation  of  Parties.  Whenever  the parties are
required to cooperate  with each other under this Lease but are entitled to
reimbursement  for their  out-of-pocket  costs to third parties,  the party
that is  obligated  to  cooperate  shall  provide an estimate of such third
party costs to the party  requesting such  cooperation and obtain the prior
written  approval from such other party not to be unreasonably  withheld or
delayed before such costs are incurred.

                  (u)  Reconciliation.  Nothing in this Lease shall prevent
or impair Tenant from performing its obligations or observing its covenants
under the  Existing  Space  Leases.  Further,  nothing in this Lease  shall
prevent or impair any of the Existing  Tenants from exercising their rights
and privileges under the Existing Space Leases. No such action by Tenant or
the Existing  Tenants in accordance with the Existing Space Leases shall be
deemed to be a breach or default by Tenant under this Lease.

                  (v) Memorandum of Lease. Upon request of either party the
other party shall promptly  execute and deliver a memorandum or other short
form  version of this  Lease  setting  forth the basic  terms of this Lease
excluding Rent. The party recording such memorandum, short form version, or
other  document  giving  notice  of  this  Lease  shall  pay  any  and  all
recordation and transfer taxes due in connection with such recordation.

                  (w)  Financial  Reports.  In the event that  Tenant is no
longer a publicly  traded  company with common stock  trading on either the
New York Stock  Exchange,  the American  Stock Exchange or the NASDAQ Stock
Exchange  (or, in the event the Tenant's  stock is no longer traded on such
exchanges, or a successor or reasonably equivalent exchange),  Tenant shall
supply  Landlord,  within  ten (10)  business  days of  Landlord's  request
therefor (to be no more  frequent  than once per year),  copies of Tenant's
most recent  financial  reports.  Such reports  shall (i) include an income
statement, balance sheet, statement owner's equity and statement of


 
<PAGE>
 
cash flows,  (ii) shall be audited by a certified public  accountant or, to
the extent audited Financial  Reports are not otherwise  obtained by Tenant
for other purposes,  certified by the chief financial officer of Tenant, to
his/her  knowledge,  as being true, correct and complete financial reports,
and (iii) shall be dated no later than twelve  months  prior to  Landlord's
request. Notwithstanding the foregoing, in the event that Landlord requests
such financial  reports within one hundred twenty (120) days after Tenant's
fiscal year end, Tenant shall have up to one hundred twenty (120) days from
such fiscal year end to supply such  reports to Landlord;  provided  Tenant
has given Landlord its most recent  financial  reports and such reports are
not dated  earlier  than twelve (12) months  prior to Tenant's  fiscal year
end.

                  (x)  Landlord's  Affiliates.   Notwithstanding   anything
contained  in  this  Lease  to the  contrary,  any  act or  omission  of an
affiliate  of  Landlord  on any  Excluded  Areas  shall not be a default of
Landlord under this Lease. In no event shall this provision be construed in
any  manner as a waiver of any right  that  Tenant  has at law or in equity
against such affiliate as a result of such act or occurrence.



                          [SIGNATURE PAGE FOLLOWS]
<PAGE>
 
                  IN WITNESS  WHEREOF,  the parties hereto have caused this
Lease to be executed as of the day and year stated herein.

                                 LANDLORD:

                                 LCOR CLARKSBURG L.L.C.
                                 By: Clarksburg Management, Inc.


                                 By: /s/ Michael T. Goulder

                                 Name: Michael T. Goulder

                                 Title: Vice President



                                 TENANT:

                                 COMSAT CORPORATION


                                 By: /s/ Allen E. Flower

                                 Name: Allen E. Flower

                                 Title: Vice President and
                                        Chief Financial Officer
<PAGE>
 
                                 SCHEDULE I



         AAA:                       Section 11(b)
         Accelerated Payment:       Section 21(b)(iii)(A)
         Additional Easements:      Section 6(f)
         Additional Rent:           Section 4(b)
         Adequate Assurance of
           Future Performance:      Section 22(d)
         All Risks:                 Section 14(a)(i)
         Alterations:               Section 13(a)
         Applicable Laws:           Section 5(b)(iv)
         Appurtenances:             Section 6(d)
         Assignment:                Section 19(b)
         Base Rent:                 Section 4(a)
         Care, Care for,
           Care of:                 Section 11(a)
         Comparable Properties:     Section 14(a)(ii)
         Contents:                  Section 27(e)
         Damage:                    Section 15(a)
         Declaration:               Section 11(a)
         Default Measuring
           Period:                  Section 21(b)(iii)(B)
         Development:               Section 6(a)
         Effective Date:            Preamble
         Environmental
           Conditions:              Section 27(a)
         Escrow Account:            Section 21(b)(iii)(B)
         Escrowee:                  Section 21(b)(iii)(B)
         Events of Default:         Section 21(a)
         Excluded Area:             Section 6(d)
         Existing Space Leases:     Section 19(a)
         Existing Tenants:          Section 19(a)
         Hazardous Material:        Section 27 and 27(d)
         Holdover Period:           Section 24
         Impositions:               Section 7(a) and 7(d)
         Indemnifying Party:        Section 16(c)
         Indemnitee:                Section 16(c)
         Indemnity Payment:         Section 16(c)
         Initial Term:              Section 3(a)
         Insurance:                 Section 14(a)
         Insurance Notice:          Section 14(g)
         Intelsat:                  Section 13(c)
         Landlord:                  Preamble, Section 30(o)
         Landlord Approved SNDA:    Section 19(b)
         Lease:                     Preamble
         Lease Year:                Section 3(b)
         Liability Policy:          Section 14(a)(ii)
         Master Lease:              Section 21(a)(iii)
         Mitigation Leases:         Section 21(b)(iii)(B)
         Mortgagee:                 Section 7(e)(i)
         Net Award:                 Section 17(b)
         Operating Expenses:        Section 21(b)(iii)(B)
<PAGE>
 
         Post Default Leases:       Section 21(b)(iii)(B)
         Prime Rate:                Section 4(h)
         Purchase and Sale
           Agreement:               Recital (a)
         Remediation Obligation:    Section 27(a)
         Renewal Notice:            Section 28(b)
         Renewal Option,
           Renewal Term:            Section 28(a)
         Rent:                      Section 4(b)
         Restricted Areas:          Section 12
         Restricted Property:       Section 13(c)
         Security Deposit:          Section 29
         Signs:                     Section 9(a)
         Stipulated Rate:           Section 4(h)
         Sublease:                  Section 19(b)
         Subtenant:                 Section 19(c)
         Taken, Taking:             Section 17(a)
         Tax and Insurance
           Holdbacks:               Section 21(b)(iii)(B)
         Tenant:                    Preamble
         Tenant Approved SNDA:      Section 20(a)
         Tenant's Property:         Section 13(c)
         Term:                      Section 3(a)
         Third Party Claim:         Section 16(d)(i)
         Unavoidable Delays:        Section 30(q)
         Utilities:                 Section 8(a)
<PAGE>
 
                            SCHEDULE OF EXHIBITS



                  EXHIBIT                                         SECTION

                  Exhibit A    (Description of Land)              1(a)

                  Exhibit B    (Description of                    1(a)
                                     Main Building Area)

                  Exhibit C    (Description of                    1(a)
                                Installations Premises)

                  Exhibit D    Intentionally Omitted

                  Exhibit E    (Wire Instructions)                4(g)

                  Exhibit F    (Portion of Installations
                                Premises)                        17(c)

                  Exhibit G    (Existing Space Leases)           19(a)

                  Exhibit H    (Landlord Approved SNDA)          19(b)

                  Exhibit I    (Tenant Approved SNDA)            20(a)

                  Exhibit J    (Operations and Maintenance       27(b)
                                Plan)

<PAGE>
 
                                                                  EXHIBIT 10.52


                                      AGREEMENT

                                        AMONG

                                 COMSAT CORPORATION

                                COMSAT ARGENTINA S. A.

                                         AND

                    ICO GLOBAL COMMUNICATIONS (HOLDINGS) LIMITED

                       ICO GLOBAL COMMUNICATIONS HOLDINGS B.V.

                       ICO GLOBAL COMMUNICATIONS SERVICES INC.



                             Dated as of September 30, 1998
<PAGE>
 
                                    AGREEMENT


         This  Agreement  ("Agreement")  is made and entered into as of the
30th day of  September,1998  ("Effective  Date") by and among the following
parties:

                  COMSAT Corporation, a Washington D.C. corporation ("COMSAT
                  Corporation"),  with its  principal  place of business at
                  6560  Rock  Springs  Drive,  Bethesda,   Maryland  20817,
                  U.S.A.;

                  COMSAT ARGENTINA S. A., a sociedad anonime ("COMSAT
                  Argentina"), with its principal place of business at Carlos
                  Pellegrini 1363, 6th Floor, (1011) Buenos Aires, Argentina;

                  ICO Global  Communications  (Holdings) Limited, a Bermuda
                  corporation ("ICO Bermuda"),  with its principal place of
                  business at Clarendon  House, 2 Church Street,  Hamilton,
                  Bermuda;

                  ICO Global  Communications  Holdings  B.V., a Netherlands
                  corporation ("ICO Netherlands"), with its principal place
                  of business at  Drentestraat  20, 1083 HK Amsterdam,  The
                  Netherlands; and

                  ICO  Global  Communications  Services  Inc.,  a  Delaware
                  corporation ("ICO Services"), with its principal place of
                  business at The  Corporation  Trust Company,  1209 Orange
                  Street, Wilmington, Delaware, USA.

In consideration of the covenants contained in this Agreement,  the parties
hereto hereby agree as follows:


Section 1. Defined Terms.

Each of the terms set forth below,  when used in this Agreement,  will have
the definition set forth opposite such term:

Closing Date - The date to be agreed to by the  parties,  as more fully set
forth in Section 9 hereof.

Closing - The closing of the  transactions  contemplated  by this Agreement
pursuant to Section 9 hereof.
<PAGE>
 
COMSAT - COMSAT Corporation and COMSAT Argentina.

COMSAT  Entity - COMSAT  Corporation  and each of its direct  and  indirect
subsidiaries.

COMSAT Shares - The ICO Bermuda shares owned , respectively, on the date of
this Agreement by COMSAT  Corporation , being a total of 2,015,604  shares,
and COMSAT  Argentina , being a total of 1,226,007  shares,  as such shares
and the  number  thereof  may change to  reflect  any  changes in the share
capital of ICO  Bermuda or the  relationship  between  ICO  Bermuda and any
successor  entity at any time  during  the  period of  performance  of this
Agreement.

COMSAT Subscription Agreements - The Subscription Agreements dated January,
1995, and all amendments  thereto,  between COMSAT  Corporation  and COMSAT
Argentina,  respectively,  and a  predecessor  to ICO  Bermuda  and related
documents  and  similar  documents  between  any COMSAT  Entity and any ICO
Entity.

Distribution  Rights - All rights and  preferences  of any COMSAT Entity to
distribute  any  services  of any ICO Entity or  otherwise  act for any ICO
Entity anywhere in the world,  including but not limited to all such rights
and preferences that may have been granted or promised by any ICO Entity to
any COMSAT Entity,  including without  limitation,  any distribution rights
granted,  promised  or referred to in the  Information  Memorandum,  COMSAT
Subscription  Agreements,  actions of or  publications by any ICO Entity or
its Board of Directors, or employees or agents, or other agreement, whether
referred to as distribution  rights,  commercial rights,  gateway operator,
service  partner,   service  provider,  right  to  be  a  National  Service
Wholesaler,   National  Service  Retailer,   Service  Wholesaler,   Service
Retailer,  or otherwise . Nothing  herein shall be construed as  preventing
COMSAT from acting as a  non-exclusive  provider  to  International  Mobile
Satellite  Organization  ("Inmarsat")  for the  distribution  in the United
States of non-hand  held ICO products  for the  maritime  and  aeronautical
market  segments  or  non-hand  held  ICO  services  for the  maritime  and
aeronautical market segments.

ICO - ICO Bermuda,  ICO  Netherlands,  and ICO Services.  ICO Services is a
wholly  owned  subsidiary  of ICO  Netherlands,  which  is a  wholly  owned
subsidiary  of ICO Global  Communications  (Netherlands  Antilles)  N.V., a
Netherlands Antilles corporation, which is a wholly owned subsidiary of ICO
Global  Communications  (Operations) Limited, a Cayman Islands corporation,
which is a wholly owned subsidiary of ICO Bermuda.

ICO Entity - ICO Bermuda and each of its direct and indirect subsidiaries.

ICO   Services/USEI   Memorandum  of   Understanding   -  A  memorandum  of
understanding  in form and  substance  acceptable  to ICO Services  setting
forth in outline  form an  agreement  between  USEI and ICO  Services or an
entity  designated  by ICO Services  that would,  among other  things,  (i)
replace the Main  Agreement,  (ii) set forth USEI's consent to the transfer
by COMSAT to ICO  Services or an entity  designated  by ICO Services of the
USEI Agreement and USEI Lease
<PAGE>
 
without  condition at the request of ICO,  and (iii)  provide that the USEI
Agreement can be  terminated by COMSAT or, in the event the USEI  Agreement
has  been  transferred  to ICO  Services  or an  entity  designated  by ICO
Services,  by ICO  Services  or such  entity  without  cost to COMSAT,  ICO
Services, or such entity.

ICO  Cayman  Islands - ICO  Global  Communications  (Holdings)  Limited,  a
corporation organized under the laws of the Cayman Islands.

Information Memorandum - The Information Memorandum dated 16 September 1994
as  amended by the First  Addendum  thereto  dated 18 January  1995 and the
Second  Addendum  thereto dated 23 January 1995,  referred to in the COMSAT
Subscription  Agreement,  pursuant to which COMSAT  Corporation  and COMSAT
Argentina acquired the COMSAT Shares.

Interconnect Agreement - Interconnect Agreement dated March 5, 1997 between
COMSAT Corporation and ICO Netherlands and all amendments thereto, if any.

Licenses  -  All  licenses,  authorizations,  approvals,  and  permits  and
applications  therefor from any governmental  authority obtained or applied
for by (i) COMSAT Corporation in connection with the Interconnect Agreement
and the Main Agreement or either or in the  performance of its  obligations
thereunder or in connection with any Distribution Rights and/or (ii) COMSAT
Argentina in connection with any Distribution Rights.

Main  Agreement  - Main  Agreement  dated  March  5,  1997  between  COMSAT
Corporation and ICO Services and all amendments thereto, if any.

Main Agreement  Documents - All plans,  reports,  memoranda,  test results,
insurance  policies,  schedules and other  documents of  whatsoever  nature
created  or  obtained  by  COMSAT   Corporation  in  connection   with  the
performance of its  obligations  under the Main Agreement and  Interconnect
Agreement  or either and that are  reasonably  necessary  to  continue  the
installation,  operations,  maintenance, and interconnection of the SAN and
not subject to attorney-client privilege.

Main Agreement  Subcontracts  - All  agreements  entered into by any COMSAT
Entity with third parties pursuant to or in connection with the performance
of  COMSAT   Corporation's   obligations   under  the  Main  Agreement  and
Interconnect Agreement or either.

Parent Company  Guaranty - The Parent Company  Guaranty dated March 5, 1997
executed by ICO Cayman Islands in favor of COMSAT  Corporation  relating to
the Main Agreement and the Interconnect Agreement.

SAN - The Satellite Access Node constructed pursuant to the Main Agreement.
<PAGE>
 
Site Lease - The Lease of Earth  Station  Site dated April 4, 1997  between
COMSAT Corporation and USEI and all amendments  thereto, if any. Transition
Agreement - The Transition Agreement to be entered into by ICO Services and
COMSAT at the Closing, the form of which is attached hereto as Annex 1.

USEI - U.S. Electrodynamics, Inc., a corporation organized under the laws of
the state of Washington, USA.

USEI  Agreement  -  The  Agreement  dated  April  4,  1997  between  COMSAT
Corporation and USEI relating to the  construction and operation of the SAN
and all amendments thereto, if any.


Section 2. Payment.

At the Closing,  ICO Bermuda (or, at ICO  Bermuda's  direction,  any one or
more of the  parties  included  within the  definition  of ICO) will pay to
COMSAT,  by wire  transfer  to the bank  account  designated  in writing by
COMSAT,  in  immediately  available  funds,  the  aggregate  sum  of (i) in
consideration   for  terminating   the  Main  Agreement  and   Interconnect
Agreement,  U.S.  dollars  four  million  five  hundred  thousand  (U.S.  $
4,500,000),  and  (ii) an  additional  sum (in U.S.  dollars)  equal to all
amounts which the parties hereto agree are or will be owed by ICO to COMSAT
Corporation  through the Closing Date  pursuant to the Main  Agreement  and
Interconnect  Agreement that have not been paid as of such date,  which sum
shall be determined no ;later than five (5) days prior to the Closing.


Section 3.  Termination.

The  Interconnect  Agreement and Main Agreement  shall  terminate as of the
Closing  Date,  except  for  the  following  portions  of the  Interconnect
Agreement and Main Agreement which will remain in effect:

         (a) Sections 12,18, 19, and 34 of the Interconnect Agreement, and

         (b) Sections C10, H4, H5, H14, and H15.13 of the Main Agreement.


Section 4.  Transfers To ICO and Transition Agreement.

(A) At the  Closing,  COMSAT  Corporation  and ICO Services or other entity
designated  by ICO Services  will  execute and  deliver,  as of the Closing
Date, an Assignment and Assumption Agreement in the form attached hereto as
Annex 2, pursuant to which (i) COMSAT  Corporation  will assign or transfer
to ICO Services or other entity designated by ICO Services, all rights,
<PAGE>
 
titles,  and interests under the following,  and (ii) ICO Services or other
entity  designated  by ICO Services will assume the  obligations  of COMSAT
Corporation that arise after the Closing under the following, and (iii) ICO
Services  will  indemnify  COMSAT  against  all  claims  by  third  parties
(including  costs)  accruing  after the  Closing  in  connection  with such
assumed  obligations  and  reimburse  COMSAT for any taxes or fees that may
become  payable  as a result of such  assignment  or  transfer  of  rights,
titles, and interests under, the following:

         (1) Site Lease;

         (2) All Main Agreement Documents;

         (3) All Main Agreement Subcontracts;

         (4) All  Licenses (to the extent  transferable  and subject to any
         conditions applicable to transfer);

         (5) All rights, titles, and interests of COMSAT Corporation in and
         to all equipment, facilities, improvements,  structures, and other
         physical  property  and rights of  whatsoever  nature  acquired by
         COMSAT  Corporation  in  connection  with  or for  the  SAN  being
         constructed  pursuant to the Main Agreement or in connection  with
         the Interconnect Agreement; and

         (6) All Distribution Rights.

 (B) Except as otherwise agreed by the parties to facilitate the transition
services under the Transition Agreement, COMSAT Corporation will deliver to
ICO at or before the Closing the following  documents  which are defined in
the Main  Agreement  in whatever  state of  completion  or  readiness  such
documents may exist on the Closing Date and otherwise on an "as is" basis:

         As Built Plans
         Confidential Information (received from ICO in connection with the
         Main Agreement or Interconnect Agreement) 
         Plans
         Requisite Consents (to the extent  transferable  and  subject to any
         conditions of transfer applicable thereto) 
         Site Lease 
         Building Contract
         Copy of all Building Contractor  Insurance Policies in COMSAT's
         possession
         Warranties applicable to equipment installed pursuant to the Main
         Agreement

and all subcontracts, consulting agreements, utility agreements and similar
agreements  entered  into  by  COMSAT  Corporation  pursuant  to  the  Main
Agreement.

(C) COMSAT  Corporation  will  deliver to ICO at or before the  Closing the
following with respect to the Interconnect Agreement:
<PAGE>
 
         (1)  Confidential  Information,  as  defined  in the  Interconnect
              Agreement,   received  from  ICO  in   connection   with  the
              Interconnect Agreement,

         (2)  Names,  addresses,  telephone  numbers,  and  other  relevant
              information  relating all parties to which COMSAT Corporation
              provided quotes for ICO interconnect services, and

         (3)  Such other  information as may be in COMSAT's  possession and
              that  COMSAT  may  have  created  or  obtained  prior  to the
              Effective Date in order to perform its obligations  under the
              Interconnect  Agreement  ("ICO  Interconnect   Information"),
              provided  that  COMSAT  shall  not be  obligated  to  deliver
              quotes,  traffic  estimates  or  other  information  that  is
              derived from or represents a commingling of ICO  Interconnect
              Information and other COMSAT proprietary information (such as
              quotes  based on a bundling  of  forecasted  ICO  traffic and
              other non-ICO related traffic).

At the  request  of ICO  Services  at  any  time  during  the  term  of the
Transition  Agreement,  COMSAT will assign or otherwise transfer to a party
designated by ICO Services or amend or otherwise take all actions  required
to  substitute  such  party in  place of  COMSAT  as the  applicant  under,
whichever  ICO  Services  elects,   all  licenses  and  other  permits  and
authorizations  applied  for by COMSAT to the U.S.  Federal  Communications
Commission pursuant to the Main Agreement or Interconnect Agreement.

(D) At the Closing,  ICO Services and COMSAT will enter into the Transition
Agreement.

(E) If the Closing occurs, at the request of ICO Services at any time at or
prior to termination  of the Transition  Agreement and without the need for
further  documentation  other than the providing of written notice therefor
from ICO Services to COMSAT Corporation,  COMSAT Corporation shall transfer
to ICO  Services or other entity  designated  by ICO Services the rights of
COMSAT Corporation under the USEI Agreement, and ICO Services or such other
entity shall assume the  obligations of COMSAT  Corporation  under the USEI
Agreement that arise after such transfer.


Section 5. Registration Rights.

(A)      No ICO  Entity  will  object  to or  hinder  the  sale  by  COMSAT
         Corporation or COMSAT Argentina of any or all of the COMSAT Shares
         in a private sale not  prohibited by the rules or  regulations  of
         the U.S. Securities and Exchange  Commission ("SEC").  ICO Bermuda
         shall  promptly  register in its company  register the transfer of
         such shares  from COMSAT  pursuant to such sale from COMSAT to any
         purchaser designated by COMSAT pursuant to such sale provided such
         transfer is made in accordance  with, and not in violation of, the
         Bye-laws and/or Memorandum of Continuance of ICO Bermuda or any
         successor entity thereof and all applicable laws and regulations. 
         In furtherance thereof:
<PAGE>
 
         (1) ICO Bermuda hereby represents and warrants to COMSAT, which
             representation and warranty shall survive the execution,
             delivery, and any Closing hereunder, that as of the date of
             this Agreement there is nothing in the Bye-laws, Memorandum of
             Continuance or other charter document of ICO Bermuda that would
             restrict ICO Bermuda's ability to register such transfer of
             shares except for the provisions of Bye-laws 55, 56, and 57 of
             ICO Bermuda's Bye-laws, a copy of which are attached hereto
             as Annex 6.

         (2) Until the earlier of (i) January 1, 2000 or (ii) until  neither
             COMSAT  Corporation nor COMSAT  Argentina holds any COMSAT Shares,
             ICO Bermuda or any successor  entity shall remain current with all
             public  filings and other public  disclosures  required to be made
             with  the SEC  under  the  Securities  Exchange  Act of  1934,  as
             amended, and other applicable laws and regulations.

  (B) If  ICO  Bermuda  or  any  successor   entity   thereof  files  a
      registration statement with the SEC with respect to the offer and sale
      to the public in the  United  States of any of ICO  Bermuda's  (or any
      successor entity's) authorized and unissued ordinary shares, par value
      $0.01 per shares,  (the "ICO  Offered  Shares") at any time during the
      two year period commencing on January 1, 1999, then COMSAT Corporation
      and COMSAT Argentina will have the right to require ICO Bermuda or any
      successor entity thereof to include in such registration statement any
      COMSAT Shares owned by COMSAT  Corporation  and/or COMSAT Argentina as
      of the date of this  Agreement  which  COMSAT  Corporation  or  COMSAT
      Argentina  notifies  ICO Bermuda in writing that it desires to sell in
      the offering (the "COMSAT Offered Shares").  ICO Bermuda shall provide
      COMSAT at least  twenty days advance  written  notice of its intent to
      file any such  registration  statement  with the SEC, and COMSAT shall
      thereafter  have  fifteen  days to notify ICO Bermuda of its desire to
      sell  the  COMSAT  Offered  Shares   pursuant  to  such   registration
      statement.  The  aforementioned  right  to  require  any or all of the
      COMSAT Shares to be included in a registration  statement filed by ICO
      Bermuda or any  successor  entity with the SEC shall be subject to the
      following conditions:

      the  receipt by ICO Bermuda of a written  opinion of US legal  counsel
      reasonably  satisfactory to ICO to the effect that registration  under
      the  Securities  Act of 1933 is required  (because in the  judgment of
      such counsel there is no applicable  exemption) in connection with the
      transaction  contemplated  by COMSAT  Corporation or COMSAT  Argentina
      involving the COMSAT Offered Shares;
      in the  opinion of the lead  underwriter  for the  offering  (the lead
      underwriter  will be selected by ICO Bermuda) market  conditions would
      allow  for the  sale of both the ICO  Offered  Shares  and the  COMSAT
      Offered Shares;
      if any  ICO  shareholder  other  than COMSAT Corporation  or  COMSAT
      Argentina   to  which  ICO  Bermuda  has  given  demand  or  piggyback
      registration  rights as of the date of this  Agreement  (an "other ICO
      shareholder") demands that its ICO shares be registered,  ICO will not
      be required to include any COMSAT Offered  Shares in the registration
      unless  in the 
<PAGE>
 
     good  faith  opinion  of the lead  underwriter  market conditions  would
     allow for the sale of the ICO Offered  Shares,  the COMSAT Offered Shares
     and  the  shares  of  each  such  other  ICO shareholder;
     if as of the  closing  of the sale of the  shares  subject to any such
     registration  the lead  underwriter  deems it  necessary to reduce the
     number of shares  proposed to be sold,  any such  reduction will apply
     first to the COMSAT Offered Shares;
     COMSAT  proposes  no changes to the  underwriting  agreement  or other
     documentation required to be approved by COMSAT in connection with the
     offering (other than changes reasonably required to include the COMSAT
     Offered  Shares in such offering) if such  underwriting  agreement and
     other such  documentation  are  satisfactory  to ICO  Bermuda  and, if
     applicable,  each such other ICO shareholder;  provided such agreement
     will not (i)  obligate  COMSAT  to adhere to any  lock-up  period  for
     COMSAT  Offered  Shares not included in such  offering or (ii) provide
     for any  deferral  of payment  to COMSAT for the shares  sold by it in
     such offering; and
     COMSAT will bear its legal fees and its related costs  (including  the
     proportionate  share  of  any  NASD  and  SEC  filing  fees)  and  the
     underwriter  fees and  discounts  attributable  to the COMSAT  Offered
     Shares.


         In any  such  offering  ICO  Bermuda  will  enter  into  customary
underwriting arrangements, supply information, make requests, and otherwise
use reasonable  commercial  efforts,  including (except as indicated above)
the payment of necessary fees for the preparation,  filing, and printing of
the  registration  statement  and  exhibits  thereto  (including  copies of
preliminary  and  final  prospectuses  and to obtain  all  legal  opinions,
auditors  consents,  and comfort letters,  and participate in and cooperate
with due  diligence  activities  and any "road shows" or similar  marketing
efforts if requested by the lead  underwriter  to facilitate  the offering.
ICO Bermuda  will deliver or cause to be delivered to COMSAT such number of
copies as may be reasonably  requested by COMSAT of  preliminary  and final
registration   statements  and  prospectuses   (including  any  revised  or
supplemental  prospectuses)  and  except as  indicated  above  will pay all
expenses in connection with the  registration of the COMSAT Offered Shares.
ICO  Bermuda and any  successor  entity  thereof  will  indemnify  and hold
harmless   COMSAT  and  its   officers,   directors,   employees,   agents,
representatives   and  underwriters   against  claims,   losses,   damages,
liabilities  and  expenses  (including  attorneys  fees and sums payable in
satisfaction of judgments or decrees) resulting from or attributable to any
untrue  statement  of a material  fact or  allegedly  untrue  statement  or
alleged  omission to state  therein any material fact required to be stated
or necessary  to make any  statements  not  misleading  except  insofar as the
information  shall have been  furnished in writing to ICO Bermuda by COMSAT
Corporation or COMSAT  Argentina,  or other violations or non-compliance by
ICO Bermuda with applicable laws or regulations or contractual obligations,
relating to such offering,  and if such  indemnification  is deemed void as
against  public  policy  shall  contribute  to COMSAT such sums as would be
equal  to any  payments  otherwise  payable  to  COMSAT  and its  officers,
directors, employees, agents, representatives and underwriters to indemnify
and hold harmless each of them pursuant to this Section 6(B).
<PAGE>
 
Section 6. Representations.

(A) COMSAT  Corporation  hereby covenants and agrees that the copies of the
Site Lease,  USEI  Agreement,  and Main Agreement  Subcontracts  heretofore
delivered to ICO are the  originals or true copies of the originals of such
documents and that such  documents at the Closing will be in full force and
effect and that COMSAT will not be in breach of its obligations thereunder.
COMSAT   Corporation   hereby  represents  and  warrants  that  (i)  COMSAT
Corporation  is the  owner  free  and  clear  of  all  liens,  claims,  and
encumbrances  of the rights  attributed  to COMSAT  Corporation  under (and
subject to the terms of) the Interconnect Agreement,  Main Agreement,  Site
Lease, USEI Agreement,  and Main Agreement  Subcontracts,  and (ii) neither
COMSAT   Corporation  nor  COMSAT   Argentina  has  assigned  or  otherwise
transferred  or  encumbered or entered into any  agreements  with any third
party that creates any rights, liens, claims, and encumbrances on or to the
Distribution Rights, and (iii) COMSAT Corporation and COMSAT Argentina each
has the authority and power to enter into this Agreement and to perform its
obligations hereunder.

(B) ICO hereby represents and warrants to COMSAT and agrees that (i) ICO is the
owner free and clear of all liens,  claims,  and encumbrances of the rights
attributed to ICO under the  Interconnect  Agreement and Main Agreement and
(ii) ICO has the  authority  and power to enter into this  Agreement and to
perform its obligations hereunder, (iii) the information set forth on Annex
4 hereto with respect to registration  rights granted to other shareholders
of ICO Bermuda is true and correct,  and (iv) ICO Bermuda has  succeeded to
and is fully  liable for the  obligations  of its  predecessor,  ICO Cayman
Islands, under the Parent Company Guaranty.

(C) At the Closing, COMSAT and ICO will each execute and deliver to the other a
Representation  and Warranty Agreement in the form attached hereto as Annex
5,  pursuant to which each such party makes,  as of the Closing  Date,  the
same  covenants,  representations,  and warranties as are set forth in this
Section 6.


Section 7. Mutual Releases.

At the Closing, COMSAT and ICO will execute and deliver a Mutual Release in
the form attached hereto as Annex 3, pursuant to which COMSAT will release,
or will cause to be released,  each ICO Entity from,  and ICO will release,
or will cause to be  released,  each  COMSAT  Entity  from,  all claims and
causes of  action  whatsoever  related  to the  Distribution  Rights or any
rights  or  warranties  related  to the Main  Agreement,  the  Interconnect
Agreement,  and the Main Agreement  Subcontracts (except as provided for in
Section 3 hereto)  which any COMSAT  Entity or ICO Entity,  as the case may
be, may have against any ICO Entity or COMSAT  Entity,  as the case may be,
and COMSAT will agree not to assert (and will cause each COMSAT  Entity not
to assert) against any ICO Entity
<PAGE>
 
or any other  person or entity  not a party to this  Agreement  any  claims
arising out of or connected with the Distribution Rights and/or any matters
contained in the letter from Crowell & Moring to ICO Bermuda dated 15 April
1998 and the draft Writ sent to ICO Bermuda on 9 June 1998.


Section 8. USEI Transactions.

Forthwith after the Effective Date, COMSAT will (i) notify USEI that COMSAT
and ICO have entered into this  Agreement  and that COMSAT has no objection
to USEI  conducting  negotiations  with ICO Services in an attempt to reach
agreement  on  an  ICO  Services/USEI   Memorandum  of  Understanding  (ii)
cooperate with ICO to the extent  reasonably  requested in ICO's efforts to
enter into the ICO Services/USEI Memorandum of Understanding and (iii) seek
the written consent of USEI to assign the USEI Agreement to ICO Services or
any entity designated by ICO Services.

(B)  Forthwith  after the  Effective  Date,  ICO  Services or other  entity
designated  by ICO will  use  good  faith  efforts  to  enter  into the ICO
Services/USEI  Memorandum of Understanding not later than 60 days after the
Effective Date.


Section 9. Closing.

(A) Unless  otherwise  hereafter  mutually  agreed in  writing  by the  parties
hereto,  the Closing Date will be a date  acceptable  to COMSAT and ICO not
later than 30 days after the  Effective  Date;  PROVIDED  THAT the  Closing
shall  not  occur on such date  unless  on or prior  thereto  either of the
following  conditions  has  occurred (i) USEI and ICO Services or an entity
designated  by  ICO  Services  have  entered  into  the  ICO  Services/USEI
Memorandum of  Understanding or (ii) USEI has given (and not withdrawn) its
consent  for COMSAT to assign the USEI  Agreement  to ICO  Services  or any
entity designated by ICO Services. If neither of the conditions referred to
in (i) or (ii) of this Section 9(A) has occurred within such 30 day period,
the Closing Date shall be deferred to a date  acceptable  to ICO and COMSAT
not later than 60 days after the Effective  Date;  PROVIDED THAT if neither
of the  conditions  referred  to in (i) or (ii) of this  Section  9(A)  has
occurred on or before 60 days after the Effective  Date, each of COMSAT and
ICO will have the  right to  terminate  this  Agreement  by giving  written
notice thereof to the other party.  If this Agreement is so terminated,  no
party hereto will have any right or obligation under this Agreement.

(B) The Closing and the  performance by the parties hereto of their  respective
obligations  under this Agreement at the Closing are  conditional  upon the
occurrence or fulfillment prior to the Closing of the conditions to Closing
expressly set forth in this Agreement and the performance by COMSAT and ICO
of their respective obligations at the Closing.

(C) The  Closing  will occur at 10 o'clock  AM on the  Closing  Date in the
offices of COMSAT Corporation at 6560 Rock Springs Drive, Bethesda MD 
20817 U.S.A. At the Closing each party
<PAGE>
 
hereto will execute and deliver the  documents  required and take the other
action  required to be taken to fulfill at the Closing all the  obligations
of such part under this Agreement.


Section 10. General.

(i)      All notices  sent by COMSAT or ICO to the other party will be sent
         by telefax or  delivered  to the  address for such party set forth
         below:

         Notices to COMSAT                          Notices to ICO

         COMSAT Corporation                         ICO Global Communications
         6560 Rock Springs Drive                    1 Queen Caroline Street
         Bethesda MD 20817                          Hammersmith London W6 9 BN
         USA                                        United Kingdom
         Attention: General Counsel                 Attention: General Counsel
         Fax. No. 301-214-7145                      Fax No.  44-181-741-0851

(ii)     No party  hereto  will  have  any  right to  assign  or  otherwise
         transfer  or  encumber  its  rights  or  obligations   under  this
         Agreement.

(iii)    This Agreement  shall be governed by and interpreted and construed
         in accordance with English Law; provided, however, that all suits,
         claims, actions,  proceedings or disputes arising or brought under
         Section  5  "Registration  Rights"  of  this  Agreement  shall  be
         governed by and  interpreted  and construed in accordance with the
         laws of the State of New York without  regard to conflicts of laws
         principles.

(iv)     The parties agree that the courts of England are to have exclusive
         jurisdiction  to settle any dispute  which may arise in connection
         with the validity,  effect,  interpretation or performance of this
         Agreement or otherwise  arising out of or in connection  with this
         Agreement or any of its terms.

(v)      At the request of any party  hereto,  all the parties  hereto will
         execute and deliver  all other  documents  that may be required to
         give effect to the agreements contemplated by this Agreement.

(vi)     The  Parent  Company  Guaranty  will  remain in  effect  after the
         Closing and will cover only (i) the  obligations  of ICO  Services
         under the Transition  Agreement,  and (ii) the  obligations of ICO
         under the Main Agreement and Interconnect Agreement that remain in
         effect after the Closing  pursuant to Section 3 and the Assignment
         and Assumption Agreement hereof.
<PAGE>
 
(vii)    It is  expressly  agreed and  acknowledged  by each of the parties
         that the execution and  performance  of this Agreement is not, and
         is  not  to be  construed  as,  any  admission  whatsoever  of any
         liability on the part of any of the parties to this Agreement.

(viii)   Except to the extent  required  by  applicable  law and to parties
         with whom any party has  contracted  or may  contract or intend to
         contract  with  respect to any of the matters that are the subject
         of this  Agreement,  no party hereto shall make any  announcement,
         news release,  or other public statement  regarding this Agreement
         or its subject matter without prior written  approval of the other
         parties, such approval not to be unreasonably withheld or delayed.

(ix)     This  Agreement  sets out the entire  agreement and  understanding
         between  the  parties  in respect  of the  subject  matter of this
         Agreement. It is agreed that:

         (a)      No party  hereto  has  entered  into  this  Agreement  in
                  reliance on any  representation,  warranty or undertaking
                  of any  other  party  which is not  expressly  set out or
                  referred to in this Agreement,

         (b)      No  party  shall  have  any  remedy  in  respect  of  any
                  misrepresentation  or untrue  statement made by any other
                  party which is not contained in this Agreement, and

         (c)      This clause  shall not exclude any  liability  for fraudulent
                  misrepresentation.

(x)      At and after the Closing,  each of COMSAT and ICO will execute and
         deliver all documents and take all actions required to give effect
         to the agreements of the parties set forth in this Agreement.

(xi)     Attached  hereto and hereby made a part  hereof are the  following
         Annexes:  
         Annex 1. Form of Transition  Agreement  
         Annex 2. Form of Assignment  and  Assumption  Agreement  
         Annex 3. Form of Mutual Release
         Annex 4. Information Relating to Registration Rights granted to other
                    Shareholders of ICO Bermuda
         Annex 5. Form of Representation and Warranty Agreement
         Annex 6. Bye-laws 55, 56, and 57 of ICO Bermuda
<PAGE>
 
IN WITNESS WHEREOF,  the parties hereto have entered into this Agreement on
the date first mentioned above.


COMSAT Corporation                               ICO GLOBAL COMMUNICATIONS
                                                 (HOLDINGS) LIMITED



By: /s/ John Mattingly                           By: /s/ Olof Lundberg
    Name:  John Mattingly                        Name:  Olof Lundberg
    Title: President, COMSAT                     Title: CEO
           Satellite Services


COMSAT ARGENTINA S. A.                           ICO GLOBAL COMMUNICATIONS
                                                 HOLDINGS B.V.



By: /s/ Luis Valencia                            By: /s/ Olof Lundberg
    Name:  Luis Valencia                         Name: Olof Lundberg
    Title: President of the Board of Directors   Title: CEO



                                                 ICO GLOBAL COMMUNICATIONS
                                                 SERVICES INC.



                                                 By: /s/ Olof Lundberg
                                                 Name: Olof Lundberg
                                                 Title: CEO


<PAGE>
 
                                                                      EXHIBIT 21

                       SUBSIDIARIES OF COMSAT CORPORATION
                           (As of December 31, 1998)

     Bethesda Real Property, Inc.
     COMSAT Capital I, L.P.
     COMSAT Digital Teleport, Inc.
     COMSAT General Corporation
            COMSAT General Telematics, Inc.
            COMSAT Technology, Inc.
          CTS Transnational, Inc.
          Electromechanical Systems, Inc.
     COMSAT Government Systems, Inc.
     COMSAT International, Inc.
            BelCom, Inc.
                  ZAO BelComRus
                  BelCom Rep Office
                  ZAO MKT
                  ZAO Novocom
                  Stavropol-Cellular
            COMSAT Argentina, S.A.
            COMSAT Asia (L) Incorporated
                  Guanzhou T.H. Communication Technology Services, Ltd.
                  Tian Hang Technology Services, Ltd.
            COMSAT do Brasil Equipamentos Telecommunicacoes, Ltda.
                  COMSAT Brasil, Ltda.
            COMSAT de Colombia, S.A.
                  Comunicaciones Satelitales de Columbia, S.A.
            COMSAT Dijital Hizmetleri Ticaret Anonim Sirketi
            COMSAT de Guatemala, S.A
            COMSAT Iletisim Hizmetleri Ticaret Anonim Sirketi
            COMSAT Max Limited
            COMSAT de Mexico, S.A. de C.V.
            COMSAT de Panama, S.A.
            COMSAT Peru, S.A.
            COMSAT Venezuela, COMSATVEN, C.A.
            CIV C.I.S. Holdings, Inc.
     COMSAT Laboratories Inc.
     COMSAT Laboratories India, Inc.
            Indicom Personal Communications Private Ltd. (99%)
     COMSAT Mobile Investments, Inc.
     COMSAT Overseas, Inc. (owns 1% of Indicom Personal Communications Private
            Ltd.)
     COMSAT Personal Communications, Inc.
     CRSI Acquisition, Inc. d/b/a COMSAT RSI, JEFA Wireless Systems

<PAGE>
 
                                                                      EXHIBIT 23



                         INDEPENDENT AUDITORS' CONSENT

We consent to the incorporation by reference in COMSAT Corporation's
Registration Statement No. 2-87942 on Form S-8, Registration Statement
No. 33-5259 on Form S-8, Registration Statement No. 33-25124 on Form S-8,
Registration Statement No. 33-35364 on Form S-8, Registration Statement
No. 33-53610 on Form S-8, Registration Statement No. 33-51661 on Form S-3,
Registration Statement No. 33-54369 on Form S-8, Registration Statement
No. 33-54685 on Form S-8, Registration Statement No. 33-56331 on Form S-8,
Registration Statement No. 33-56333 on Form S-8, Registration Statement
No. 33-59531 on Form S-8, Registration Statement No. 33-59513 on Form S-8,
Registration Statement No. 33-59841 on Form S-3, Registration Statement
No. 33-33061 on Form S-3 of our report dated February 18, 1999, appearing in
this Annual Report on Form 10-K of COMSAT Corporation for the year ended
December 31, 1998.



Deloitte & Touche LLP
Washington, D.C.
March 24, 1999

<TABLE> <S> <C>

<PAGE>
 
<ARTICLE>                     5
<LEGEND>
     This schedule contains summary financial information extracted from the
     the financial statements for the year ended December 31, 1998 and is
     qualified in its entirety by reference to such financial statements.
</LEGEND>
<CIK>                         0000022698
<NAME>                        COMSAT Corporation
<MULTIPLIER>                                   1,000
<CURRENCY>                                     U.S. Dollars
       
<S>                             <C>
<PERIOD-TYPE>                   Year
<FISCAL-YEAR-END>                              DEC-31-1998
<PERIOD-START>                                 JAN-01-1998
<PERIOD-END>                                   DEC-31-1998
<EXCHANGE-RATE>                                1
<CASH>                                         30,795
<SECURITIES>                                   0
<RECEIVABLES>                                  148,175
<ALLOWANCES>                                   (17,123)
<INVENTORY>                                    0
<CURRENT-ASSETS>                               198,965
<PP&E>                                         2,507,798
<DEPRECIATION>                                 1,298,336
<TOTAL-ASSETS>                                 1,790,798
<CURRENT-LIABILITIES>                          140,802
<BONDS>                                        446,832
                          0
                                    0
<COMMON>                                       430,537
<OTHER-SE>                                     228,503
<TOTAL-LIABILITY-AND-EQUITY>                   1,790,798
<SALES>                                        0
<TOTAL-REVENUES>                               616,469
<CGS>                                          0
<TOTAL-COSTS>                                  284,053
<OTHER-EXPENSES>                               272,914
<LOSS-PROVISION>                               0
<INTEREST-EXPENSE>                             39,812
<INCOME-PRETAX>                                32,208
<INCOME-TAX>                                   5,791
<INCOME-CONTINUING>                            26,417
<DISCONTINUED>                                 0
<EXTRAORDINARY>                                0
<CHANGES>                                      0
<NET-INCOME>                                   26,417
<EPS-PRIMARY>                                  0.51
<EPS-DILUTED>                                  0.50
        

</TABLE>


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