LOCKHEED MARTIN CORP
S-4, 1999-05-12
GUIDED MISSILES & SPACE VEHICLES & PARTS
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<PAGE>
 
      As filed with the Securities and Exchange Commission on May 12, 1999
                                                        Registration No. 333-
 
- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                                --------------
                                    FORM S-4
                             REGISTRATION STATEMENT
                                     UNDER
                           THE SECURITIES ACT OF 1933
 
                                --------------
                          LOCKHEED MARTIN CORPORATION
             (Exact name of registrant as specified in its charter)
         Maryland                   3760                    52-1893632
     (State or other         (Primary standard           (I.R.S. employer
     jurisdiction of             industrial           identification number)
     incorporation or       classification code
      organization)               number)
                              6801 Rockledge Drive
                            Bethesda, Maryland 20817
                                  301-897-6000
  (Address, including zip code, and telephone number, including area code, of
                   registrant's principal executive offices)
 
                                --------------
                          Frank H. Menaker, Jr., Esq.
                   Senior Vice President and General Counsel
                          Lockheed Martin Corporation
                              6801 Rockledge Drive
                            Bethesda, Maryland 20817
                                  301-897-6000
 (Name, address, including zip code, and telephone number, including area code,
                             of agent for service)
                                   Copies to:
          David G. Litt, Esq.                    Alan C. Myers, Esq.
         O'Melveny & Myers LLP           Skadden, Arps, Slate, Meagher & Flom
 555 13th Street, N.W., Suite 500 West                   LLP
      Washington, D.C. 20004-1109                  919 Third Avenue
             202-383-5300                   New York, New York 10022-3897
                                --------------       212-735-3000
        Approximate date of commencement of proposed sale to the public:
 
   As soon as practicable after the effectiveness of this Registration
Statement and the satisfaction or waiver of all other conditions to the merger
contemplated by the Agreement and Plan of Merger, dated as of September 18,
1998, described in the Proxy Statement/Prospectus forming part of this
Registration Statement.
 
   If the securities being registered on this form are to be offered in
connection with the formation of a holding company and there is compliance with
General Instruction G, check the following box. [_]
 
   If this form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, check the following box and
list the Securities Act registration statement number of the earlier effective
registration statement for the same offering. [_]
 
   If this form is a post-effective amendment filed pursuant to Rule 462(d)
under the Securities Act, check the following box and list the Securities Act
registration statement number of the earlier effective registration statement
for the same offering. [_]
                                --------------
                        CALCULATION OF REGISTRATION FEE
<TABLE>
- -------------------------------------------------------------------------------------------
- -------------------------------------------------------------------------------------------
<CAPTION>
 Title of each class of                    Proposed maximum  Proposed maximum   Amount of
    securities to be       Amount to be     offering price  aggregate offering registration
       registered          registered(1)       per unit          price(2)         fee(3)
- -------------------------------------------------------------------------------------------
<S>                      <C>               <C>              <C>                <C>
Common Stock ($1.00 par
 value)................  39,342,917 shares       N/A          $1,281,005,378     $282,455
- -------------------------------------------------------------------------------------------
- -------------------------------------------------------------------------------------------
</TABLE>
(1) Based upon the number of shares of Lockheed Martin common stock expected to
    be issued in connection with the transactions described herein, assuming
    that 17,565,312 shares of COMSAT common stock are tendered in the tender
    offer and that all outstanding options to purchase COMSAT common stock are
    exercised.
(2) Estimated solely for the purpose of determining the registration fee in
    accordance with Rule 457(f)(1). Based upon the average of the high and low
    prices of COMSAT common stock on May 5, 1999 on the New York Stock Exchange
    ($32.56), multiplied by the number of shares to be registered.
(3) The amount of the registration fee is calculated based on 31,204,726 shares
    rather than 39,342,917 shares as indicated in the second column of this
    table. The 31,204,726 shares upon which the registration fee is based
    represents the difference between the total number of shares of COMSAT
    common stock outstanding as of April 30, 1999 on a fully-diluted basis
    (56,908,229) and the number of shares of COMSAT common stock for which a
    fee was previously paid in connection with the filing with the Commission
    on September 25, 1998 of the Schedule 14D-1 by Lockheed Martin Corporation
    and its wholly-owned subsidiary Regulus, LLC, relating to the tender offer
    to purchase shares of COMSAT common stock (25,703,503). Pursuant to Rule
    457(b), the fee includes $79,541 previously paid on April 1, 1999 in
    connection with the filing with the Commission of the preliminary proxy
    materials relating to the transaction described herein.
 
                                --------------
   The Registrant hereby amends this Registration Statement on such date or
dates as may be necessary to delay its effective date until the Registrant
shall file a further amendment which specifically states that this Registration
Statement shall thereafter become effective in accordance with Section 8(a) of
the Securities Act of 1933 or until the Registration Statement shall become
effective on such date as the Commission, acting pursuant to said Section 8(a)
may determine.
 
- --------------------------------------------------------------------------------

- --------------------------------------------------------------------------------

<PAGE>
 
                               ----------------
 
                           PROXY STATEMENT/PROSPECTUS
 
                               ----------------
                   [LOGO OF COMSAT CORPORATION APPEARS HERE]
                                                                    May 12, 1999
Dear Shareholders:
 
   The 1999 Annual Meeting of Shareholders will be held at 9:30 a.m., local
time, on Friday, June 18, 1999, at COMSAT's headquarters, located at 6560 Rock
Spring Drive, Bethesda, Maryland.
 
   At the annual meeting, you will be asked to approve the merger between
Lockheed Martin Corporation and COMSAT. After the proposed merger, COMSAT will
be a wholly-owned subsidiary of Lockheed Martin, and you will be shareholders
of Lockheed Martin. In the merger, you will receive one share of Lockheed
Martin common stock for each share of COMSAT common stock that you own. The
proposed merger will be the second and final step in Lockheed Martin's
acquisition of COMSAT. The first step is a tender offer, which was commenced on
September 25, 1998, by a subsidiary of Lockheed Martin, to purchase a non-
controlling interest of up to 49% of the outstanding shares of COMSAT common
stock at a price of $45.50 per share.
 
   We anticipate that between 31,087,220 and 39,342,917 shares of Lockheed
Martin common stock will be issued to COMSAT shareholders in connection with
the merger. These amounts are based on April 30, 1999 records and represent the
difference between the number of shares of COMSAT common stock outstanding on a
fully-diluted basis and the maximum and minimum number of shares of COMSAT
common stock that may be acquired in the tender offer, respectively. The actual
number of shares issued in connection with the merger will depend upon the
number of shares tendered in the tender offer and the number of shares for
which dissenters' rights are properly exercised. Lockheed Martin common stock
is listed on the New York Stock Exchange under the symbol "LMT."
 
   Your Board of Directors has determined that the merger is consistent with,
and advances, the long-term business strategy of COMSAT and recommends that you
vote in favor of the merger at the annual meeting.
 
   At the annual meeting, you will also vote to elect 12 members to the Board
of Directors, to appoint Deloitte & Touche LLP as COMSAT's independent public
accountants for the year ending December 31, 1999, and to act upon a
shareholder proposal. Your Board of Directors has approved the election of the
director nominees and the appointment of Deloitte & Touche LLP as COMSAT's
independent public accountants and recommends that you vote in favor of these
proposals. Your Board of Directors does not recommend the shareholder proposal
and recommends that you vote against this proposal.
 
   The attached proxy statement/prospectus provides you with detailed
information about COMSAT, Lockheed Martin and the proposed merger. You should
read this document, particularly the section describing risk factors relating
to the merger that begins on page 12. We look forward to the successful
combination of COMSAT and Lockheed Martin and to your continued support as a
shareholder of the combined company.
 
                                   Sincerely,
                                        
                                   /s/ Edwin I. Colodny

                                   Edwin I. Colodny
                                   Chairman of the Board
 
 
                                   /s/ Betty C. Alewine

                                   Betty C. Alewine
                                   President and Chief Executive Officer
 
 Neither the Securities and Exchange Commission nor any state securities
 commission has approved the merger, nor have they determined if this proxy
 statement/prospectus is accurate or adequate. Any representation to the
 contrary is a criminal offense.
 
<PAGE>
 
                   [LOGO OF COMSAT CORPORATION APPEARS HERE]
 
                               ----------------
 
                    NOTICE OF ANNUAL MEETING OF SHAREHOLDERS
 
                               ----------------
 
To the Shareholders of COMSAT
Corporation:
 
 
   The 1999 Annual Meeting of                The close of business on April
Shareholders of COMSAT Corporation        30, 1999 is the record date for
will be held in the Charyk                determining which shareholders are
Conference Center, COMSAT                 entitled to vote at the annual
headquarters, 6560 Rock Spring            meeting and at any adjournment or
Drive, Bethesda, Maryland, on             postponement of the annual meeting.
Friday, June 18, 1999, at 9:30 a.m.,      A list of shareholders entitled to
local time, for the following             vote at the annual meeting will be
purposes:                                 available for your examination at
                                          COMSAT's headquarters for a period
     1. to consider and vote on a         of five days before the annual
  proposal to approve an agreement        meeting during regular business
  and plan of merger dated as of          hours.
  September 18, 1998 among COMSAT,   
  Lockheed Martin and a wholly-              A map and directions by car and   
  owned subsidiary of Lockheed            the Washington Metro to COMSAT's     
  Martin and to approve the merger        headquarters appear at the end of    
  and other transactions described        the proxy statement/prospectus.      
  in the merger agreement. You can                                             
  find the full text of the merger           Please read the proxy             
  agreement at the back of this           statement/prospectus for information 
  document as Appendix I;                 relating to COMSAT, Lockheed Martin, 
                                          and the terms and conditions of the  
     2. to elect 12 directors;            merger. Other important information   
                                          is incorporated by reference from     
     3. to appoint Deloitte &             other documents. Please review all    
  Touche LLP to serve as COMSAT's         these materials before completing     
  independent public accountants          the enclosed proxy card.              
  for the year ending December 31,                                              
  1999;                                
                                           By order of the Board of Directors,
     4. to act on a shareholder
  proposal that recommends COMSAT             /s/ WARREN Y. ZEGER
  affirm its political non-                     Warren Y. Zeger
  partisanship and require the                  Vice President, General
  reporting of certain practices;               Counsel and Secretary
  and
                                          Bethesda, Maryland
     5. to act upon any other             May 12, 1999
  matters that may properly come
  before the annual meeting and any
  adjournment or postponement of
  the annual meeting.
 
   To assure your representation at the annual meeting, please complete, sign,
date and return the enclosed proxy card promptly in the enclosed prepaid
envelope. You can also vote in person at the annual meeting. Please do not send
in your stock certificates with your proxy card.
 
This proxy statement/prospectus is dated May 12, 1999 and is first being mailed
                   to shareholders on or about May 14, 1999.
<PAGE>
 
                               TABLE OF CONTENTS
 
<TABLE>
<CAPTION>
                                                                           Page
                                                                           ----
<S>                                                                        <C>
QUESTIONS AND ANSWERS ABOUT THE MERGER....................................   1
SUMMARY...................................................................   3
  The Companies...........................................................   3
  Our Recommendations To Shareholders.....................................   3
  Reasons for the Merger..................................................   3
  Votes Required For Approval.............................................   4
  Interests of COMSAT Executive Officers and Directors in the Merger......   4
  Conditions to the Merger................................................   4
  Termination of the Merger Agreement.....................................   4
  Termination Fee; Termination Expenses...................................   5
  Non-Solicitation of Competing Transactions..............................   5
  Regulatory Approvals....................................................   5
  Amendment of the Satellite Act..........................................   5
  Tax Consequences of the Merger..........................................   5
  Accounting Treatment....................................................   6
  Opinion of COMSAT's Financial Advisor...................................   6
  Other Transaction Documents.............................................   6
  Comparative Per Share Market Price Information..........................   6
  Material Differences in the Rights of Shareholders......................   6
  Forward-Looking Statements May Prove Inaccurate.........................   7
  Lockheed Martin Selected Historical Consolidated Financial Information..   8
  COMSAT Selected Historical Consolidated Financial Information...........   9
  Summary Selected Unaudited Pro Forma Combined Condensed Financial
   Information............................................................  10
  Comparative Per Share Information.......................................  11
RISK FACTORS..............................................................  12
  Value of Lockheed Martin Common Stock You will Receive in the Merger
   will Fluctuate.........................................................  12
  Lack of Certainty that the Merger will be Tax Free to You...............  12
  Lockheed Martin Global Telecommunications' Business is Relatively New
   and has a Limited Operating History....................................  13
  The Expected Benefits of the Merger May Not Occur.......................  13
  A Significant Period of Time May Elapse Before the Completion of the
   Tender Offer or the Merger.............................................  13
  Only One Shareholder Vote will be Taken on the Merger...................  13
  The Satellite Act Must be Amended to Permit the Merger..................  14
  Lockheed Martin Must Receive Approvals from the FCC to Complete the
   Tender Offer and the Merger............................................  14
  Antitrust Regulatory Agencies May Oppose or Impose Conditions on the
   Merger.................................................................  15
  The Merger Costs will be Substantial....................................  15
  The Interests of COMSAT Executive Officers and Directors in the Merger
   May be Different From Yours............................................  15
FORWARD-LOOKING STATEMENTS--SAFE HARBOR PROVISIONS........................  16
THE COMSAT ANNUAL MEETING.................................................  17
  When and Where the Annual Meeting will be Held..........................  17
  What will be Voted Upon.................................................  17
  Only Shareholders of Record as of April 30, 1999 are Entitled to Vote...  17
  Number of Shares that Must be Present for a Vote to be Taken............  17
  Votes Required for Approval.............................................  17
</TABLE>
<PAGE>
 
<TABLE>
<CAPTION>
                                                                           Page
                                                                           ----
<S>                                                                        <C>
  Voting Your Shares and How Proxies are Counted..........................  18
  Revoking Your Proxy.....................................................  18
  Soliciting Proxies......................................................  18
ITEM 1. APPROVAL OF THE MERGER............................................  19
  Background of the Merger................................................  19
  Recommendations of the COMSAT Board of Directors; Reasons for the
   Merger.................................................................  21
  Lockheed Martin's Reasons for the Merger................................  22
  Opinion of COMSAT's Financial Advisor...................................  23
  Interests of COMSAT Executive Officers and Directors in the Merger......  31
  Accounting Treatment....................................................  36
  Material U.S. Federal Income Tax Consequences...........................  36
  Regulatory Approvals....................................................  39
  Appraisal Rights........................................................  42
  Resale Restrictions.....................................................  43
THE MERGER AGREEMENT......................................................  44
  The Tender Offer........................................................  44
  Conditions to the Tender Offer..........................................  44
  Employee Benefits.......................................................  45
  Exchange Procedures.....................................................  45
  Interim Operations......................................................  46
  No Solicitation.........................................................  46
  Reasonable Efforts to Complete the Tender Offer and the Merger..........  47
  Directors' and Officers' Insurance; Indemnification.....................  48
  Conditions to the Merger................................................  48
  Representations and Warranties..........................................  49
  Termination; Termination Fees...........................................  49
  Fees and Expenses.......................................................  51
  Other Transaction Documents.............................................  51
THE COMPANIES.............................................................  54
  Lockheed Martin.........................................................  54
  Deneb Corporation, Lockheed Martin's merger subsidiary..................  54
  COMSAT..................................................................  54
MARKET DATA...............................................................  56
LOCKHEED MARTIN SELECTED HISTORICAL CONSOLIDATED FINANCIAL INFORMATION....  57
COMSAT SELECTED HISTORICAL CONSOLIDATED FINANCIAL INFORMATION.............  58
UNAUDITED PRO FORMA COMBINED CONDENSED FINANCIAL INFORMATION..............  59
COMPARISON OF SHAREHOLDERS' RIGHTS........................................  64
OWNERSHIP OF COMSAT COMMON STOCK..........................................  77
  Record Date.............................................................  77
  Beneficial Ownership of Principal Shareholders and Management...........  77
  Ownership and Voting Limitations........................................  79
ITEM 2. ELECTION OF DIRECTORS.............................................  79
  Board of Directors......................................................  79
  Voting for Directors....................................................  79
  Requirements for Nominations and Shareholder Proposals..................  80
  Nominees for Election as Directors......................................  81
  Presidentially Appointed Directors......................................  83
  Committees of the COMSAT Board of Directors.............................  84
  Directors Compensation..................................................  85
  Compensation Committee Interlocks, Insider Participation and Related
   Party Transactions.....................................................  89
</TABLE>
 
                                       ii
<PAGE>
 
<TABLE>
<CAPTION>
                                                                          Page
                                                                          ----
<S>                                                                       <C>
COMMITTEE ON COMPENSATION AND MANAGEMENT DEVELOPMENT REPORT ON EXECUTIVE
 COMPENSATION............................................................  89
EXECUTIVE COMPENSATION...................................................  92
CHANGE IN CONTROL ARRANGEMENTS........................................... 101
PERFORMANCE GRAPH........................................................ 102
ITEM 3. APPOINTMENT OF INDEPENDENT PUBLIC ACCOUNTANTS.................... 103
ITEM 4. ACTION UPON A SHAREHOLDER PROPOSAL............................... 103
OTHER MATTERS............................................................ 104
LEGAL MATTERS............................................................ 104
EXPERTS.................................................................. 104
WHERE YOU CAN FIND MORE INFORMATION...................................... 105
DIRECTIONS TO THE COMSAT BUILDING........................................ 107
APPENDIX I: MERGER AGREEMENT.............................................   I
APPENDIX II: SECTION 29-373 OF THE DISTRICT OF COLUMBIA BUSINESS
 CORPORATION ACT.........................................................  II
APPENDIX III: OPINION OF DONALDSON, LUFKIN & JENRETTE SECURITIES
 CORPORATION............................................................. III
APPENDIX IV: RESTATED ARTICLES OF INCORPORATION OF COMSAT CORPORATION....  IV
</TABLE>
 
                                      iii
<PAGE>
 
 
                    QUESTIONS AND ANSWERS ABOUT THE MERGER
 
Q:  Why are the two companies proposing to merge? How will I benefit?
 
A:  The merger will result in you having a stake in one of the nation's
    leading companies. The merger combines the greater resources of Lockheed
    Martin with the telecommunications services expertise of COMSAT. The
    combined company will have the ability to meet the increased demand for
    broadband, Internet and virtual private network services in the global
    telecommunications services market. The combined company will also be more
    competitive in this market than either company on a stand-alone basis. We
    believe that the merger will accelerate long-term growth and increase
    shareholder value.
 
Q:  I tendered my shares in the tender offer. Can I still vote these shares at
    the annual meeting?
 
A:  Yes. You can and should still vote your tendered shares at the annual
    meeting. You will be voting on whether to approve the merger, even though
    the tender offer has not yet been completed.
 
Q:  What will I receive in the merger?
 
A:  In the merger, you will receive one share of Lockheed Martin common stock
    in exchange for each share of COMSAT common stock that you own. Lockheed
    Martin will not issue fractional shares. Instead, if you own fractional
    shares of COMSAT common stock, you will receive cash for those shares.
 
   If you tender shares in the tender offer, you will receive $45.50 for each
   share of COMSAT common stock that you sell in the tender offer, subject to
   proration, and will not receive Lockheed Martin common stock for those
   shares in the merger.
 
Q:  Is the exchange ratio fixed?
 
A:  Yes. The exchange ratio of one share of COMSAT common stock for one share
    of Lockheed Martin common stock will not change even if the price for
    Lockheed Martin common stock increases or decreases before the merger is
    completed. The market value of Lockheed Martin common stock that you
    receive in the merger will almost certainly change and may be higher or
    lower than its current market value.
 
Q:  Do I have appraisal rights?
 
A:  Yes. District of Columbia law permits you to dissent from the merger and
    have the fair value of your shares of COMSAT common stock appraised by a
    court and paid to you in cash. To do this, you must follow the procedures
    set forth under District of Columbia law, including filing specific
    notices and not voting your shares in favor of the merger. The relevant
    provisions of the District of Columbia law governing this process are
    attached to this proxy statement/prospectus as Appendix II.
 
Q:  What happens to my future dividends?
 
A:  As a shareholder of Lockheed Martin, you will no longer receive dividends
    on COMSAT common stock in the amount of $.05 per share per quarter, or
    $.20 per share per year. Instead, you will receive dividends paid on
    Lockheed Martin common stock in the amount of $0.22 per share per quarter,
    or $0.88 per share per year. Although Lockheed Martin currently expects to
    pay these dividends, it has the discretion to change these payments in the
    future.
 
Q:  What do I need to do now?
 
A:  Please vote. Indicate on your proxy card how you want to vote, and sign,
    date and mail the proxy card in the enclosed return envelope as soon as
    possible.
 
   You may attend the annual meeting and vote in person rather than voting by
   proxy. In addition, you may revoke your proxy and change your vote before
   or at the annual meeting.
 
                                       1
<PAGE>
 
Q:  How do I vote shares that I hold through the COMSAT Corporation Savings and
    Profit-Sharing Plan?
 
A:  You will receive separate instructions as to how to direct the trustee to
    vote the shares held in your plan account.
 
Q:  Should I send in my stock certificates now?
 
A:  No. After the merger is completed, you will receive instructions on how to
    exchange your COMSAT stock certificates for Lockheed Martin stock
    certificates.
 
   If you wish to tender your shares in the tender offer, you should follow the
   instructions in the tender offer materials which were provided separately in
   September 1998.
 
Q:  What are the major conditions to the merger?
 
A:  To complete the merger, COMSAT shareholders must approve the merger,
    various regulatory approvals must be obtained, and Congress must amend the
    Communications Satellite Act of 1962.
 
Q:  When do you expect the merger to be completed?
 
A:  We are working toward completing the merger as quickly as possible.
    However, we do not yet know when the merger will be completed as many
    conditions to the merger are beyond our control.
 
   If Congress does not adopt amendments to the Satellite Act in the next few
   months, the merger will not occur in 1999, even if the tender offer is
   completed. If, however, Congress adopts amendments to the Satellite Act in
   the 1999 legislative session, the merger may occur in late 1999 or in early
   2000, depending upon when approvals of the FCC and Department of Justice
   necessary to complete the merger are obtained.
 
   If the tender offer is not completed by September 18, 1999, either Lockheed
   Martin or COMSAT may terminate the merger agreement. Lockheed Martin or
   COMSAT may elect not to do this or together may elect to amend the merger
   agreement so that the tender offer can be completed after September 18,
   1999.
 
   If the merger is not completed by September 18, 2000, either Lockheed Martin
   or COMSAT may terminate the merger agreement. Lockheed Martin or COMSAT may
   elect not to do this or together may elect to amend the merger agreement so
   that the merger can be completed after September 18, 2000.
 
Q:  Who can help answer my questions?
 
A:  If you have questions about the merger, you should contact:
 
                               COMSAT Corporation
                             6560 Rock Spring Drive
                            Bethesda, Maryland 20817
                               Investor Relations
                           Toll Free: (888) 233-5777
 
   If you have questions about the tender offer, you should contact the
Information Agent:
 
                               Morrow & Co., Inc.
                           445 Park Avenue, 5th Floor
                            New York, New York 10022
                          Phone Number: (212) 754-8000
                           Toll Free: (800) 566-9061
 
 
                                       2
<PAGE>
 
 
                                    SUMMARY
 
   This section summarizes selected information from this proxy
statement/prospectus and may not contain all of the information that is
important to you. This proxy statement/prospectus is meant only to apply to the
merger and does not address the tender offer in detail. To understand the
merger fully and for a more complete description of the legal terms of the
merger, you should read this document, including the appendices and other
documents to which it refers. We have included a copy of the merger agreement
in this document as Appendix I. The merger agreement, and not this document, is
the document that governs the merger. For information on how to obtain the
documents that we have filed with the SEC, including the tender offer
materials, see "Where You Can Find More Information" on page 105.
 
The Companies
(See page 54)
 
Lockheed Martin Corporation
 
6801 Rockledge Drive
Bethesda, Maryland 20817
(301) 897-6000
http://www.lockheedmartin.com
 
   Lockheed Martin is a highly diversified global enterprise principally
engaged in the conception, research, design, development, manufacture,
integration and operation of advanced technology products and services.
Lockheed Martin currently conducts its principal business through:
 
   .  the Space & Strategic Missiles sector;
 
   .  the Electronics sector;
 
   .  the Aeronautics sector;
 
   .  the Information & Services sector; and
 
   .  the Energy & Environment sector.
 
   It is expected that the combined businesses and operations of COMSAT and
Lockheed Martin Global Telecommunications, Inc., a subsidiary of Lockheed
Martin, will be a sixth sector.
 
   For additional information about Lockheed Martin and its businesses, see
"The Companies--Lockheed Martin" and "Where You Can Find More Information."
 
COMSAT Corporation
 
6560 Rock Spring Drive
Bethesda, Maryland 20817
(301) 214-3000
http://www.comsat.com
 
   COMSAT is a global provider of satellite communications services and digital
networking services and technology. COMSAT operates through four principal
business segments:
 
   .  COMSAT World Systems;
 
   .  COMSAT Mobile Communications;
 
   .  COMSAT International; and
 
   .  COMSAT Laboratories.
 
   For additional information about COMSAT and its businesses, see "The
Companies--COMSAT" and "Where You Can Find More Information."
 
Our Recommendations To Shareholders
(See page 21)
 
   Your Board of Directors has determined that the merger is consistent with,
and advances, the long-term business strategy of COMSAT and is fair to you.
Your Board of Directors has by a unanimous vote, excluding directors who were
absent or recused themselves, approved the merger and recommends that you vote
in favor of the merger. Your Board of Directors further recommends that you
vote in favor of the election of the 12 director nominees and in favor of the
appointment of Deloitte & Touche LLP as COMSAT's independent public
accountants. However, your Board of Directors recommends that you vote against
the shareholder proposal.
 
Reasons for the Merger
(See page 21)
 
   Your Board of Directors considered a number of factors in determining to
approve the merger and recommend it to you, including:
 
                                       3
<PAGE>
 
 
  .  the consideration payable to you in the tender offer and merger;
 
  .  proposed legislation that, if enacted, could significantly and adversely
     harm COMSAT's core businesses and the value of your investment in
     COMSAT;
 
  .  consolidation trends and global alliances within the satellite and
     telecommunications industries which have adversely affected, and are
     expected to continue to adversely affect, COMSAT's relative competitive
     position;
 
  .  COMSAT's need for continued capital investment to expand COMSAT
     International's digital networking business; and
 
  .  Lockheed Martin's expertise in the research, manufacture and integration
     of advanced-technology satellite systems and products, and the
     opportunity to effect a strategic combination with Lockheed Martin with
     its complementary assets and telecommunications growth strategy.
 
Votes Required For Approval
(See page 17)
 
   To approve the merger, the affirmative vote of two-thirds of the shares of
COMSAT common stock outstanding on the record date is required. If you do not
vote at the annual meeting on the merger proposal, either in person or by
proxy, you will effectively be voting against the merger proposal.
 
   Directors are elected by a plurality of the votes represented at the annual
meeting, if a quorum is present.
 
   For all other matters, the approval of a majority of the votes represented
at the annual meeting is required, if a quorum is present.
 
Interests of COMSAT Executive Officers and Directors in the Merger
(See page 31)
 
   A number of COMSAT executive officers and directors may have interests in
the merger that are different from or in addition to and greater than yours and
which may be conflicts of interest. These executive officers have employment
agreements or severance arrangements that will pay substantial additional
benefits or accelerate the payment of benefits as a result of the merger. These
executive officers and the members of COMSAT's Board of Directors also
participate in benefit plans that will pay substantial additional benefits or
accelerate the payment of benefits as a result of the merger.
 
Conditions to the Merger
(See page 48)
 
   The merger will be completed only if the conditions set forth in the merger
agreement are satisfied or, to the extent permissible, waived. Some of these
conditions are:
 
  .  completion of the tender offer;
 
  .  amendment of the Satellite Act to permit the completion of the merger;
 
  .  approval of the merger by COMSAT's shareholders;
 
  .  the receipt of all consents or approvals from governmental authorities;
     and
 
  .  there is no event that has had or would reasonably be expected to have a
     significant adverse effect on COMSAT.
 
Termination of the Merger Agreement
(See page 49)
 
   Lockheed Martin and COMSAT may terminate the merger agreement and abandon
the tender offer and the merger if any of the following occurs:
 
  .  COMSAT's shareholders do not approve the merger by September 18, 1999;
 
  .  the tender offer is not completed by September 18, 1999;
 
  .  the merger is not completed by September 18, 2000;
 
  .  a court or other governmental authority permanently prohibits the tender
     offer or the merger;
 
  .  COMSAT's Board of Directors recommends an alternative transaction with a
     third party or otherwise withdraws or adversely changes its approval or
     its recommendation of the merger;
 
                                       4
<PAGE>
 
 
  .  any of the other company's representations or warranties in the merger
     agreement are not materially true; or
 
  .  the other company does not materially comply with its obligations under
     the merger agreement.
 
Termination Fee; Termination Expenses
(See page 49)
 
   COMSAT generally must pay Lockheed Martin a termination fee of $75 million
and reimburse its expenses up to $5 million if COMSAT terminates the merger
agreement to accept a superior proposal.
 
Non-Solicitation of Competing Transactions
(See page 45)
 
   The merger agreement generally restricts COMSAT's ability to discuss
alternative transactions for the sale of COMSAT with third parties beyond what
is required by the COMSAT Board of Directors' fiduciary duties. COMSAT must
inform Lockheed Martin of the terms of any superior proposal it receives from a
third party unless the COMSAT Board of Directors believes that its fiduciary
duties require that it not do so.
 
Regulatory Approvals
(See page 39)
 
   Federal Communications Commission. To complete the tender offer:
 
  .  the FCC must approve the transfer of control of COMSAT's common carrier
     subsidiary, COMSAT Government Systems, Inc., to Regulus, LLC, a
     subsidiary of Lockheed Martin; and
 
  .  Regulus must receive FCC authorization to become an authorized carrier
     and to acquire a non-controlling interest of up to 49% of the
     outstanding shares of COMSAT common stock in the tender offer.
 
   On October 16, 1998, Lockheed Martin and COMSAT filed with the FCC the
required applications. The FCC is currently reviewing these applications.
 
   Following the amendment of the Satellite Act, Lockheed Martin, Regulus and
COMSAT must apply to the FCC for the authority necessary to transfer control of
COMSAT and complete the merger. The nature of any approval requirement will
depend upon the details of any amendment to the Satellite Act.
 
   Antitrust. The Hart-Scott-Rodino Antitrust Improvements Act of 1976
prohibits Lockheed Martin and COMSAT from completing the tender offer and the
merger until after they have furnished specific information and materials to
the Department of Justice and the Federal Trade Commission, and a required
waiting period has ended. The Department of Justice is currently reviewing
filings by Lockheed Martin and COMSAT, and additional information is being
provided to the Department of Justice.
 
   As with any merger in the U.S., the Federal Trade Commission or the
Department of Justice has the authority to challenge the merger on antitrust
grounds before or after the merger is completed.
 
Amendment of the Satellite Act
(See page 41)
 
   Under the Satellite Act, no one may own more than 50% of the outstanding
shares of COMSAT common stock. Therefore, until Congress amends the Satellite
Act, the merger cannot be completed. Legislation is currently pending in the
Senate and is expected to be introduced in the House of Representatives later
this year to amend the Satellite Act to, among other things, eliminate this
restriction. We do not know when or if this legislation will be enacted.
 
Tax Consequences of the Merger
(See page 36)
 
   The exchange of COMSAT common stock for Lockheed Martin common stock, other
than cash paid for fractional shares, is intended to be tax free to you for
U.S. federal income tax purposes. The intended tax-free treatment of the merger
is based on facts and assumptions outside of the control of Lockheed Martin and
COMSAT that may change before the merger is completed. The merger is not
conditioned upon the tax-free nature of the
 
                                       5
<PAGE>
 
transaction. As a result, you will not know whether the merger will be tax free
to you when you vote on the merger.
 
   The tax consequences of the merger to you will depend on your own situation.
For a more detailed discussion of the tax consequences of the merger, see
"Material U.S. Federal Income Tax Consequences." You should consult your tax
advisors for a full understanding of these tax consequences.
 
Accounting Treatment
(See page 36)
 
   Lockheed Martin will account for the merger as a purchase of COMSAT, which
means the purchase price, including costs directly related to the merger, will
be allocated to the assets acquired and liabilities assumed based on their
estimated fair values at the time the merger is completed with any excess
allocated to goodwill.
 
Opinion of COMSAT's Financial Advisor
(See page 23)
 
   Donaldson, Lufkin & Jenrette Securities Corporation, COMSAT's financial
advisor in connection with the merger, has delivered its opinion to the COMSAT
Board of Directors that, as of September 18, 1998, the consideration to be
received by COMSAT shareholders pursuant to the merger agreement was fair to
such shareholders from a financial point of view. The full text of the opinion,
which sets forth the factors considered and the assumptions made by COMSAT's
financial advisor, is attached as Appendix III to this proxy
statement/prospectus. You should read the opinion.
 
Other Transaction Documents
(See page 51)
 
   Shareholders Agreement. COMSAT has agreed to, upon the completion of the
tender offer, elect three individuals selected by Lockheed Martin to COMSAT's
Board of Directors and to appoint one of the three individuals as a member of
each committee of the COMSAT Board of Directors.
 
   Registration Rights Agreement. COMSAT has granted Lockheed Martin
registration rights for the COMSAT common stock acquired in the tender offer,
if the merger is not completed.
 
   Carrier Acquisition Agreement. To facilitate the completion of the tender
offer and the merger, COMSAT Government Systems will merge with Regulus, and
Regulus will acquire the common carrier business of COMSAT Government Systems.
As a prospective common carrier, Regulus has applied to the FCC to become an
authorized carrier and for authority to acquire the shares of COMSAT common
stock that it has offered to purchase in the tender offer.
 
Comparative Per Share Market Price Information
(See page 56)
 
   The table below shows the closing price per share on the New York Stock
Exchange Composite Tape for Lockheed Martin common stock and COMSAT common
stock on September 18, 1998, the last full trading day before the public
announcement of the proposed merger and on May 7, 1999, the last day for which
it was practicable to obtain this information prior to the mailing of this
proxy statement/prospectus.
 
<TABLE>
<CAPTION>
                                                                  Lockheed
                                                         COMSAT    Martin
                                                         Common    Common
                          Date                           Stock     Stock
                          ----                           ------   --------
<S>                                                      <C>      <C>
September 18, 1998......................................  $34 1/8   $50
May 7, 1999.............................................  $33       $43/7///16/
</TABLE>
 
Material Differences in the Rights of Shareholders
(See page 64)
 
   There are material differences between your rights as a COMSAT shareholder
under District of Columbia law and COMSAT's articles of incorporation and
bylaws, and the rights you will have as a shareholder of Lockheed Martin under
 
                                       6
<PAGE>
 
Maryland law and Lockheed Martin's charter and bylaws.
 
Forward-Looking Statements May Prove Inaccurate
(See page 16)
 
   COMSAT and Lockheed Martin have made forward-looking statements in this
proxy statement/ prospectus and in the documents to which we have referred you.
Forward-looking statements include information concerning possible or assumed
future results of operations of Lockheed Martin, COMSAT or the combined company
following the merger. Many factors could affect the future financial results of
Lockheed Martin, COMSAT or the combined company following the merger and could
cause those results to differ materially from those expressed in the forward-
looking statements contained or incorporated by reference in this proxy
statement/prospectus.
                                       7
<PAGE>
 
 
     Lockheed Martin Selected Historical Consolidated Financial Information
 
   Lockheed Martin is providing the following consolidated financial
information to aid you in analyzing the financial aspects of the merger. This
information was derived from audited consolidated financial statements for 1994
through 1998. Lockheed Martin was formed in 1995 as the result of the
combination of Lockheed Corporation and Martin Marietta Corporation. Financial
information for 1994 was derived from the financial statements of those
companies under the pooling of interests method of accounting. This information
is only a summary, and you should read it in conjunction with Lockheed Martin's
historical consolidated financial statements and related notes contained in its
annual reports and other information filed with the SEC. See "Where You Can
Find More Information" on page 105.
 
<TABLE>
<CAPTION>
                                                      At or For
                                               Year Ended December 31,
                                       ----------------------------------------
                                       1998(2) 1997(3)  1996(4) 1995(5) 1994(6)
                                       ------- -------  ------- ------- -------
                                        (In millions, except per share data)
<S>                                    <C>     <C>      <C>     <C>     <C>
Income Statement Data:
  Net sales........................... $26,266 $28,069  $26,875 $22,853 $22,906
  Earnings before cumulative effect of
   change in accounting...............   1,001   1,300    1,347     682   1,055
  Net earnings........................   1,001   1,300    1,347     682   1,018
  Net earnings (loss) per common
   share:(1)
    Basic:
      Before cumulative effect of
       change in accounting...........    2.66   (1.56)    3.40    1.64    2.66
      Net earnings (loss).............    2.66   (1.56)    3.40    1.64    2.56
    Diluted:
      Before cumulative effect of
       change in accounting...........    2.63   (1.56)    3.04    1.54    2.43
      Net earnings (loss).............    2.63   (1.56)    3.04    1.54    2.34
  Cash dividends per common share(1)..     .82     .80      .80     .67     .57
Balance Sheet Data:
  Total assets........................ $28,744 $28,361  $29,540 $17,558 $17,979
  Short-term borrowings...............   1,043     494    1,110     --      --
  Current maturities of long-term
   debt...............................     886     876      180     722     285
  Long-term debt......................   8,957  10,528   10,188   3,010   3,594
  Stockholders' equity................   6,137   5,176    6,856   6,433   6,086
</TABLE>
- --------
(1) All share and per share amounts have been restated to reflect a two-for-one
    stock split in the form of a stock dividend in December 1998.
(2) Includes the effects of a nonrecurring and unusual pretax charge of $233
    million, $183 million after tax, or $.48 per diluted share.
(3) Includes the effects of a tax-free gain of $311 million and the effects of
    nonrecurring and unusual pretax charges of $457 million, $303 million after
    tax which, on a combined basis, decreased diluted loss per share by $.02.
    Loss per share also includes the effects of a deemed dividend resulting
    from a transaction with the holder of Lockheed Martin's series A preferred
    stock which reduced the basic and diluted per share amounts by $4.93.
(4) Reflects a business combination with Loral Corporation effective April
    1996. Includes the effects of a nonrecurring pretax gain of $365 million,
    $351 million after tax, and nonrecurring pretax charges of $307 million,
    $209 million after tax which, on a combined basis, increased diluted
    earnings per share by $.32.
(5) Includes the effects of merger related and consolidation expenses totaling
    $690 million, $436 million after tax, or $.99 per diluted share.
(6) Includes a cumulative effect adjustment related to Lockheed Martin's change
    in the method of accounting for its leveraged employee stock ownership
    plan.
 
                                       8
<PAGE>
 
 
         COMSAT Selected Historical Consolidated Financial Information
 
   COMSAT is providing the following consolidated financial information to aid
you in analyzing the financial aspects of the merger. This information is
derived from COMSAT's audited consolidated financial statements for 1994
through 1998. The information is only a summary, and you should read it in
conjunction with COMSAT's historical consolidated financial statements and
related notes contained in its annual reports and other information filed with
the SEC. See "Where You Can Find More Information" on page 105.
 
<TABLE>
<CAPTION>
                                                   At or For
                                            Year Ended December 31,
                                      -----------------------------------------
                                       1998   1997(1)    1996    1995    1994
                                      ------- --------- ------- ------- -------
                                      (In millions, except per share data)
<S>                                   <C>     <C>       <C>     <C>     <C>
Summary of Operations:
 Revenues............................ $   616  $   563  $   545 $   508 $   500
 Operating expenses..................     557      481      438     388     367
 Operating income....................      59       82      107     120     133
 Income from continuing operations...      26       29       36      44      69
 Net income (loss)...................      26      (64)       9      38      78
 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 (at end of
 period):
 Total assets........................   1,791    1,895    2,097   2,022   1,851
 Long-term debt......................     447      462      578     590     511
 Stockholders' equity................     659      586      842     839     827
Dividends:
 Dividends paid......................      10       17       38      37      34
 Dividends paid per share............    0.20    0.345     0.78    0.78    0.76
 Distribution of Ascent Entertainment
  Group, Inc. shares.................     --       195      --      --      --
</TABLE>
- --------
(1) COMSAT began accounting for Ascent Entertainment Group, Inc. and
    substantially all of COMSAT RSI, Inc. as discontinued operations in 1997.
    Accordingly, all prior periods were restated to present Ascent and COMSAT
    RSI as discontinued operations.
 
                                       9
<PAGE>
 
 
            Summary Selected Unaudited Pro Forma Combined Condensed
                             Financial Information
 
   The following unaudited pro forma combined condensed financial information
is provided to give you a better picture of what the results of operations and
financial position of the combined businesses of Lockheed Martin and COMSAT
might have been had the tender offer and the merger occurred on an earlier
date. The unaudited pro forma combined condensed income statement data combines
information from the historical consolidated statements of earnings of Lockheed
Martin and COMSAT giving effect to the tender offer and the merger as if they
each occurred at January 1, 1998. The unaudited pro forma combined condensed
balance sheet data combines information from the historical consolidated
balance sheets of Lockheed Martin and COMSAT giving effect to the tender offer
and the merger as if they had been completed on December 31, 1998.
 
   This information is provided for illustrative purposes only. This
information does not necessarily reflect the following:
 
  .  what the results of operations or financial position of the combined
     company would have been if the tender offer and the merger had actually
     occurred on the dates noted above, or
 
  .  what the combined company's actual future consolidated results of
     operations or financial position will be.
 
   This information also does not reflect the following:
 
  .  cash obtained from transactions related to Lockheed Martin's equity
     interests in various investment holdings as a funding source for the
     tender offer,
 
  .  any transition or restructuring costs associated with combining Lockheed
     Martin and COMSAT, as these cannot presently be estimated, or
 
  .  the effect of any potential changes in revenues or any operating savings
     which may be achieved by combining the resources of Lockheed Martin and
     COMSAT.
 
   The merger will be accounted for as a purchase of COMSAT by Lockheed Martin.
In connection with the merger, the purchase price will be allocated to the
assets acquired and liabilities assumed based upon their estimated fair values
at the completion of the merger, with any excess allocated to goodwill.
 
   Refer to "Unaudited Pro Forma Combined Condensed Financial Information" on
page 59 for more details related to the information displayed.
 
<TABLE>
<CAPTION>
                                                        At or For
                                                        Year Ended
                                                    December 31, 1998
                                           ------------------------------------
                                           (In millions, except per share data)
      <S>                                  <C>
      Pro Forma Income Statement Data:
        Net sales........................                $26,822
        Net earnings.....................                    909
        Net earnings per common share:
          Basic..........................                   2.25
          Diluted........................                   2.21
        Cash dividends per common share..                    .82
      Pro Forma Balance Sheet Data:
        Total assets.....................                $32,618
        Short-term debt..................                  1,213
        Current maturities of long-term
         debt............................                    886
        Long-term debt...................                 10,187
        Stockholders' equity.............                  7,456
</TABLE>
 
                                       10
<PAGE>
 
 
                       Comparative Per Share Information
 
   The following table sets forth historical and pro forma Lockheed Martin
information, and historical and pro forma equivalent COMSAT information, on a
per share basis for earnings, dividends declared and book value.
 
   Pro forma net earnings were derived from the pro forma information presented
under "Unaudited Pro Forma Combined Condensed Financial Information" on page
59. Pro forma cash dividends declared per share reflect Lockheed Martin's cash
dividends declared in the period indicated. The historical book value per share
information was based upon outstanding shares of common stock for each
respective company. The number of outstanding shares for Lockheed Martin common
stock has been adjusted, for the pro forma data presented, to include the
shares of Lockheed Martin common stock estimated to be issued in the merger, as
if the merger had been completed as of December 31, 1998.
 
   The information set forth below is only a summary, and you should read it in
conjunction with the Unaudited Pro Forma Combined Condensed Financial
Information on page 59, and the respective audited consolidated financial
statements of Lockheed Martin and COMSAT. The audited consolidated financial
statements of Lockheed Martin and COMSAT are incorporated in this proxy
statement/prospectus by reference. See "Where You Can Find More Information" on
page 105.
 
<TABLE>
<CAPTION>
                                                                   At or For
                                                                  Year Ended
                                                               December 31, 1998
                                                               -----------------
                                                                 (In dollars)
     <S>                                                       <C>
     Historical:
       Per share of Lockheed Martin common stock:
         Book value...........................................      $16.18
         Cash dividends.......................................         .82
         Net earnings:
           Basic..............................................        2.66
           Diluted............................................        2.63
       Per share of COMSAT common stock:
         Book value...........................................       12.52
         Cash dividends.......................................         .20
         Net earnings:
           Basic..............................................         .51
           Diluted............................................         .50
     Unaudited Pro Forma:
       Per share of Lockheed Martin common stock:
         Book value...........................................      $18.36
         Cash dividends.......................................         .82
         Net earnings:
           Basic..............................................        2.25
           Diluted............................................        2.21
       Per equivalent share of COMSAT common stock:(1)
         Book value...........................................       18.36
         Cash dividends.......................................         .82
         Net earnings:
           Basic..............................................        2.25
           Diluted............................................        2.21
</TABLE>
 
- --------
(1) Per equivalent common share data is calculated by multiplying the pro forma
    amounts per share of Lockheed Martin common stock by the exchange ratio to
    be used in the merger of one share of Lockheed Martin common stock for each
    share of COMSAT common stock.
 
                                       11
<PAGE>
 
                                  RISK FACTORS
 
   You should consider the following risks in deciding whether to approve the
merger. These matters should be considered along with the other information
included or incorporated by reference in this proxy statement/prospectus.
 
Value of Lockheed Martin Common Stock You will Receive in the Merger will
Fluctuate
 
   Upon completion of the merger, each share of COMSAT common stock will be
exchanged for one share of Lockheed Martin common stock. This exchange ratio is
fixed and will not be adjusted for any increase or decrease in the price of
either Lockheed Martin common stock or COMSAT common stock. As a result, the
value of the Lockheed Martin common stock you receive in the merger will vary
depending on fluctuations in the stock's value and almost certainly will not be
the same as on the date of this proxy statement/prospectus, the annual meeting,
the closing of the tender offer or the closing of the merger. Fluctuations may
be the result of changes in the business, operations or prospects of Lockheed
Martin, general market and economic conditions or other factors. Neither COMSAT
nor its shareholders have the ability to terminate the merger agreement if the
value of Lockheed Martin common stock declines, which may occur after the vote
on the merger. A significant period of time may elapse between the date of the
vote on the merger and the date you receive shares of Lockheed Martin common
stock following completion of the merger. During that period, the value of
Lockheed Martin common stock will remain subject to market fluctuations.
 
Lack of Certainty that the Merger will be Tax Free to You
 
   It is intended that the exchange of your shares of COMSAT common stock for
shares of Lockheed Martin common stock, other than cash paid for fractional
shares, will constitute a tax-free reorganization under the Internal Revenue
Code and will be tax free to you for U.S. federal income tax purposes. For the
merger to qualify as a tax-free reorganization so that you will not recognize
gain or loss on the exchange of COMSAT common stock for Lockheed Martin common
stock, all of the following must occur:
 
  .  the value of the shares of Lockheed Martin common stock deliverable as a
     result of the merger must be at least 40% of the total consideration
     received by COMSAT shareholders as a result of the tender offer and the
     merger. For example,
 
    (a) if Lockheed Martin purchases 49% of the outstanding shares of
        COMSAT common stock in the tender offer at $45.50 per share, and
 
    (b) if the price of Lockheed Martin common stock is less than $29.14
        per share on the last full trading day prior to the completion of
        the merger,
 
    then the Lockheed Martin common stock received by COMSAT shareholders
    would be less than 40% of the total consideration received by COMSAT
    shareholders in the tender offer and the merger.
 
  .  COMSAT and Lockheed Martin must receive legal opinions that the merger
     will qualify as a tax-free reorganization.
 
  .  COMSAT and Lockheed Martin must receive the consents and approvals
     necessary, except where the failure to obtain these consents or
     approvals would not reasonably be expected to have a material adverse
     effect on COMSAT, so that when the merger occurs, Lockheed Martin's
     subsidiary acquires the business and properties of COMSAT and it, not
     COMSAT, "survives" the merger; in this proxy statement/prospectus, we
     call a merger where the Lockheed Martin subsidiary survives a "forward
     merger." The most significant consent or approval required in connection
     with the merger, other than the amendment of the Satellite Act, is that
     the U.S. government must recognize the Lockheed Martin subsidiary as the
     U.S. participant in INTELSAT. If the U.S. government does not do so,
     then COMSAT must "survive" the merger to preserve its business.
 
                                       12
<PAGE>
 
   If COMSAT "survives" the merger, no such consents or approvals would be
needed, but the merger likely would not qualify as a tax-free reorganization
and, therefore, would result in your being subject to taxation. In this proxy
statement/prospectus, we call a merger where COMSAT survives a "reverse
merger."
 
Lockheed Martin Global Telecommunications' Business is Relatively New and has a
Limited Operating History
 
   After the merger, COMSAT's business operations and the operations of
Lockheed Martin Global Telecommunications will be integrated. Lockheed Martin
announced the formation of Lockheed Martin Global Telecommunications in August
1998 to concentrate and expand Lockheed Martin's role in the global
telecommunications services business. Lockheed Martin Global Telecommunications
is subject to all the risks inherent in a new business enterprise, including
risks associated with unanticipated problems, liabilities and contingencies,
and diversion of management attention. In addition, Lockheed Martin has limited
prior experience in the global telecommunications services business which is
the focus of Lockheed Martin Global Telecommunications. If Lockheed Martin
Global Telecommunications and its management team cannot overcome these risks
and others that may arise, this new line of business may have a material
adverse effect on Lockheed Martin's business, operating results, financial
condition and cash flows.
 
The Expected Benefits of the Merger May Not Occur
 
   COMSAT and Lockheed Martin entered into the merger agreement with the
expectation that the merger will accelerate the growth and expansion of
Lockheed Martin Global Telecommunications. Consolidating functions and
integrating disparate departments, systems and procedures present significant
management challenges. The merger will present special risks, including
possible unanticipated liabilities and costs, and diversion of management
attention.
 
A Significant Period of Time May Elapse Before the Completion of the Tender
Offer or the Merger
 
   We expect a significant period of time to elapse before the completion of
the tender offer while Lockheed Martin and COMSAT seek the regulatory approvals
required to satisfy the conditions to the tender offer. The tender offer is
currently scheduled to expire on July 2, 1999. Lockheed Martin and Regulus have
agreed to extend, as necessary, the expiration date of the tender offer one or
more additional times until at least September 18, 1999 while Lockheed Martin
and Regulus seek the necessary regulatory approvals.
 
   Because Congress must amend the Satellite Act and additional regulatory
approvals are needed to complete the merger, there may be a further significant
period of time between the completion of the tender offer and the completion of
the merger. We do not know when or if Congress will amend the Satellite Act to
permit the merger or if any of the required regulatory approvals will be
obtained.
 
Only One Shareholder Vote will be Taken on the Merger
 
   There will be only one shareholder vote on the merger. Lockheed Martin and
COMSAT do not presently intend to seek additional shareholder approval of the
merger even if there is a significant period of time or material events occur
between the date of the annual meeting and the completion of the tender offer,
or between the completion of the tender offer and the completion of the merger.
Material events may include the occurrence of any of the contingencies that
would allow one or both of the parties to determine not to proceed with the
merger and a decision by that party or the parties to waive the contingency and
proceed with the merger. This would occur for example if Lockheed Martin were
to agree to restrictive conditions on its businesses or operations imposed by
either the Department of Justice or the FCC in its approval of the transaction.
 
                                       13
<PAGE>
 
The Satellite Act Must be Amended to Permit the Merger
 
   The merger cannot be completed unless Congress amends the Satellite Act.
Under the Satellite Act, no one may own more than 50% of the outstanding shares
of COMSAT common stock. Legislation is currently pending in the Senate, and is
expected to be introduced in the House of Representatives later this year, to
amend the Satellite Act to repeal the current ownership and governance
restrictions applicable to COMSAT. In 1998, the House of Representatives passed
a bill amending the Satellite Act which was not passed by the Senate. Had the
bill been enacted into law in the form passed by the House of Representatives,
it would have had a material adverse effect on COMSAT's business. If Congress
enacts legislation that could reasonably be expected to have a significant
adverse effect on COMSAT, Lockheed Martin, following consultation with COMSAT,
would have the right to elect not to complete the merger. We do not know when
or if Congress will amend the Satellite Act, or whether any amendment will
permit the completion of the merger or will contain terms that could reasonably
be expected to have a significant adverse effect on COMSAT.
 
Lockheed Martin Must Receive Approvals from the FCC to Complete the Tender
Offer and the Merger
 
   To complete the tender offer, Lockheed Martin must obtain all consents and
approvals required by the FCC, including the receipt by Regulus of FCC
authorization to become an authorized carrier. Under the Satellite Act, to be
eligible to become an authorized carrier, Regulus must first become a common
carrier. COMSAT Government Systems holds an FCC common carrier authorization.
The purpose of the acquisition of COMSAT Government Systems by Regulus under
the carrier acquisition agreement is for Regulus to acquire the FCC common
carrier authorization currently held by COMSAT Government Systems.
 
   On October 16, 1998, Lockheed Martin, Regulus and COMSAT applied to the FCC
for authority to transfer control of COMSAT Government Systems to Regulus and
for approval for Regulus to become an authorized carrier and to acquire a non-
controlling interest of up to 49% of the outstanding shares of COMSAT common
stock in the tender offer. Under the Communications Act of 1934, the Satellite
Act and the FCC's rules, applicants must show that the grant of each
application is consistent with the public interest, convenience and necessity,
and that the applicant is qualified to hold these FCC authorizations. The FCC
is currently reviewing these applications. In addition, a number of competitors
of COMSAT and other communications common carriers have filed with the FCC
petitions in opposition to these applications or petitions to impose conditions
on the grant of the applications which could have a significant adverse effect
on COMSAT. We do not know when or if the requisite FCC approvals will be
obtained to permit the acquisition of COMSAT Government Systems by Regulus and
the completion of the tender offer.
 
   Lockheed Martin expects that, following any amendment of the Satellite Act,
Lockheed Martin, Regulus and COMSAT will be required to apply to the FCC for
the authority to transfer control of COMSAT in a process similar to the
applications submitted by the parties with respect to the transfer of control
of COMSAT Government Systems. The precise nature of any approval requirement
will depend upon the details of any amendment to the Satellite Act. We do not
know when or if the relevant provisions of the Satellite Act will be amended,
or when or if the requisite FCC approvals will be obtained to permit the
completion of the merger. Historically, FCC reviews can take several months to
complete, however, the FCC review may be completed more quickly due to the FCC
review of the transfer of control of COMSAT Government Systems.
 
   On January 21, 1999, Representative Tom Bliley, Chairman of the House
Committee on Commerce, and Senator Conrad Burns, Chairman of the Senate
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, to purchase more than 10% of the outstanding shares
of COMSAT common stock prior to Congress adopting satellite reform legislation.
If the FCC does not proceed with its review of Lockheed Martin's applications
related to the tender offer, or if the FCC's review does not otherwise proceed
on the schedule that Lockheed Martin and COMSAT anticipated, the tender offer
may take longer than expected to be completed. Further, if the FCC delays its
review, and if Congress does not make rapid progress on satellite reform
legislation, the tender offer may not be completed by September 18, 1999. If
this occurs, under the terms of the merger agreement, Lockheed Martin or COMSAT
could terminate the merger agreement, or elect not to exercise this right and
extend this date.
 
                                       14
<PAGE>
 
Antitrust Regulatory Agencies May Oppose or Impose Conditions on the Merger
 
   Under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, Lockheed
Martin and COMSAT must file specific information with the Federal Trade
Commission and the Department of Justice, and a waiting period must expire or
terminate before the tender offer or the merger may be completed. The
Department of Justice is currently reviewing the transactions and has requested
additional information from both Lockheed Martin and COMSAT. At any time before
or after the completion of the tender offer, the Department of Justice could
take action under the antitrust laws to:
 
    (1) enjoin the tender offer or the merger,
 
    (2) require divestiture of the shares of COMSAT common stock purchased in
  the tender offer or acquired in the merger, or
 
    (3) require divestiture of substantial assets of Lockheed Martin or
  COMSAT.
 
   The merger agreement, however, provides that Lockheed Martin is not required
to agree to divest any of its businesses or assets or to any other restrictions
if the Lockheed Martin Board of Directors determines in good faith that such
agreement is not in the best interests of Lockheed Martin. We do not know
whether the Department of Justice will permit the HSR Act waiting period to
expire without imposing substantial conditions on COMSAT or Lockheed Martin. We
also do not know whether a third party will challenge the merger on antitrust
grounds or what the result of a third party challenge might be. If any of the
transactions contemplated by the merger agreement have not occurred within one
year after the HSR Act waiting period expires or is terminated, Lockheed Martin
and COMSAT must re-file notification and report forms with the Federal Trade
Commission and the Department of Justice with respect to the transactions that
have not been completed in the one-year period. A new HSR Act waiting period
and review process will begin from the date the filings are made.
 
The Merger Costs will be Substantial
 
   COMSAT and Lockheed Martin estimate they will incur combined transaction
costs of approximately $89 million associated with the merger. Transaction
costs incurred by COMSAT will be charged to operations as they are incurred,
and those incurred by Lockheed Martin will be included as part of the COMSAT
purchase price.
 
The Interests of COMSAT Executive Officers and Directors in the Merger May be
Different From Yours
 
   Some of COMSAT's directors and executive officers have interests in the
merger that may be different from or in addition to and greater than yours and
which may be conflicts of interests.
 
   In connection with the transactions contemplated by the merger agreement,
COMSAT:
 
    (1) amended employment agreements with three executive officers,
 
    (2) adopted the Retention Bonus Plan, and
 
    (3) amended the Change in Control Severance Plan.
 
   The completion of the merger will constitute a change in control under the
employment agreements and the Change in Control Severance Plan. Upon a change
in control, the term of each employment agreement will automatically end on the
third anniversary of the change in control. In addition, the executive officers
will receive, among other things, retention bonuses and severance benefits and
payments under specified circumstances. The amended employment agreements also
provide that if a change in control occurs and:
 
  .  if the executive and Lockheed Martin are unable to reach an agreement
     regarding the terms of the executive's employment within 30 days
     following the completion of the merger and the executive's employment is
     terminated, or
 
  .  if the executive continues to be employed until the expiration of the
     executive's employment term,
 
then the executive will receive enhanced benefits under COMSAT's Insurance and
Retirement Plan for Executives.
 
                                       15
<PAGE>
 
   The Retention Bonus Plan generally provides retention bonuses and severance
payments instead of the retention bonuses to key employees, including certain
executive officers, who remain employed by COMSAT, or whose employment is
terminated under specified circumstances, following the signing of the merger
agreement. The amended Severance Plan generally provides severance payments and
benefits to key employees, including certain executive officers, of COMSAT
whose employment is terminated under specified circumstances following a change
in control of COMSAT.
 
   The vesting of all options and other awards granted under COMSAT's stock
plans will accelerate upon completion of the merger. In addition, Lockheed
Martin will provide indemnification and liability protection for directors and
executive officers of COMSAT for six years following the completion of the
merger.
 
               FORWARD-LOOKING STATEMENTS--SAFE HARBOR PROVISIONS
 
   This proxy statement/prospectus contains or incorporates by reference
statements that, to the extent that they are not recitations of historical
fact, constitute "forward-looking statements" within the meaning of Section 27A
of the Securities Act and Section 21E of the Exchange Act. The words "believe,"
"estimate," "anticipate," "project," "intend," "expect" and similar expressions
are intended to identify forward-looking statements. All forward-looking
statements involve risks and uncertainties related to, among other things, the
following:
 
  .  regulatory approvals may not be obtained or obtained in a timely manner;
 
  .  Congress may not amend the Satellite Act at all, or may not amend it in
     a timely manner, or may amend it in a manner that has or could
     reasonably be expected to have a significant adverse effect on COMSAT;
 
  .  expected cost savings from the merger may not be fully realized or
     realized within the expected time frame;
 
  .  severance and change in control costs may be larger than expected;
 
  .  costs or difficulties relating to the integration of COMSAT's and
     Lockheed Martin's businesses may be greater than expected; and
 
  .  pro forma data does not necessarily reflect what the combined company's
     results of operations or financial condition would have been or will be
     in the future.
 
   You are cautioned not to place undue reliance on forward-looking statements
as these speak only as of the date of this proxy statement/prospectus. Neither
Lockheed Martin nor COMSAT undertakes any obligation to publicly release any
revisions to forward-looking statements to reflect events, circumstances or
changes in expectations after the date of this proxy statement/prospectus, or
to reflect the occurrence of unanticipated events. Lockheed Martin and COMSAT
intend that forward-looking statements in this document, and documents
incorporated by reference, be subject to the safe harbor protection provided by
Sections 27A of the Securities Act and 21E of the Exchange Act. For a
discussion identifying additional important factors that could cause actual
results to vary materially from those anticipated in any forward-looking
statements, you should read Lockheed Martin's and COMSAT's respective SEC
filings.
 
                                       16
<PAGE>
 
                           THE COMSAT ANNUAL MEETING
 
   This proxy statement/prospectus is being provided in connection with the
solicitation of proxies from you by the COMSAT Board of Directors for use at
the annual meeting.
 
When and Where the Annual Meeting will be Held
 
   The annual meeting will be held in the Charyk Conference Center, COMSAT
Headquarters, 6560 Rock Spring Drive, Bethesda, Maryland 20817, on Friday, June
18, 1999, starting at 9:30 a.m., local time.
 
What will be Voted Upon
 
   At the annual meeting, you will be asked to consider and vote upon:
 
  .  a proposal to approve the merger in which COMSAT will become a wholly-
     owned subsidiary of Lockheed Martin and the merger agreement;
 
  .  a proposal to elect 12 members to the Board of Directors;
 
  .  a proposal to appoint Deloitte & Touche LLP as independent public
     accountants for the year ending December 31, 1999;
 
  .  a shareholder proposal to recommend that COMSAT affirm its political
     non-partisanship and require the reporting of certain practices; and
 
  .  other matters that may properly come before the annual meeting,
     including any postponements or adjournments of the meeting.
 
Only Shareholders of Record as of April 30, 1999 are Entitled to Vote
 
   The COMSAT Board of Directors has fixed the close of business on April 30,
1999 as the record date. Only COMSAT shareholders of record on the record date
are entitled to notice of and to vote at the annual meeting. On the record
date, there were 52,695,937 shares of COMSAT common stock outstanding, held by
approximately 27,503 shareholders of record, and entitled to vote at the annual
meeting.
 
Number of Shares that Must be Present for a Vote to be Taken
 
   The presence, in person or by proxy, of the holders of one-third of the
shares of COMSAT common stock then issued and outstanding and entitled to vote
at the annual meeting is necessary to constitute a quorum at the annual meeting
for all matters, except the election of directors which requires the presence,
in person or by proxy, of the holders of a majority of the outstanding shares
of COMSAT common stock.
 
Votes Required for Approval
 
  .  The merger must be approved by the affirmative vote, in person or by
     proxy, of the holders of two-thirds of the shares of COMSAT common stock
     outstanding on the record date and entitled to vote at the annual
     meeting.
 
  .  Directors are elected by a plurality of the votes represented at the
     annual meeting, if a quorum is present.
 
  .  For all other matters, the approval of a majority of the votes
     represented at the annual meeting is required, if a quorum is present.
 
   As of the record date, COMSAT's directors and executive officers and their
affiliates beneficially owned 5.79% of the COMSAT common stock.
 
 
                                       17
<PAGE>
 
   You are entitled to one vote per share owned by you. However, with respect
to the election of directors, you may cumulate your votes. See "Item 2.
Election of Directors."
 
   If fewer shares of COMSAT common stock are voted in favor of the merger
proposal than the number required for approval, the annual meeting will be
postponed or adjourned to give us additional time to solicit and obtain
additional proxies or votes. At any subsequent reconvening of the annual
meeting, we will vote all proxies in the same manner as we would have voted the
proxies at the annual meeting, except for any proxies that have effectively
been revoked or withdrawn.
 
Voting Your Shares and How Proxies are Counted
 
   We will vote all shares of COMSAT common stock represented by properly
executed proxies received before or at the annual meeting and not revoked as
instructed on the proxies. If no instructions are indicated on a properly
executed and returned proxy, we will vote the proxy in favor of the merger
proposal, the election of the director nominees, and the appointment of
Deloitte & Touche LLP as COMSAT's independent public accountants. We will also
vote the proxy against the shareholder proposal.
 
   A properly executed proxy marked "Abstain," although counted for purposes of
determining a quorum, will not be voted in favor of or against any proposal.
However, because the affirmative vote of two-thirds of the shares of COMSAT
common stock is required for approval of the merger proposal, a proxy marked
"Abstain" will have the effect of a vote against the merger proposal. Under the
rules of the New York Stock Exchange, brokers and nominees cannot exercise
their voting discretion on the merger proposal. For this reason, without
specific instructions from you, brokers and nominees cannot vote your shares on
the merger proposal. This circumstance is called a broker non-vote. A broker
non-vote will have the effect of a vote against the merger proposal. Shares of
COMSAT common stock represented by broker non-votes will, however, be counted
for purposes of determining a quorum at the annual meeting.
 
   If you hold shares of COMSAT common stock through the COMSAT Corporation
Savings and Profit-Sharing Plan, you will receive separate instructions as to
how to direct the trustee to vote the shares held in your plan account.
 
Revoking Your Proxy
 
   You may revoke your proxy at any time before its use:
 
  .  by delivering to COMSAT's Corporate Secretary a signed notice of
     revocation,
 
  .  by a later dated vote by proxy, signed and returned, or
 
  .  by attending the annual meeting and voting in person.
 
   Your attendance at the annual meeting will not in itself constitute the
revocation of a proxy.
 
Soliciting Proxies
 
   In addition to solicitation by mail, directors, officers and employees of
COMSAT may solicit proxies in person without additional compensation. COMSAT
will reimburse brokerage houses and other custodians, nominees and fiduciaries
for their expenses in sending the proxy material to beneficial owners. COMSAT
has retained D.F. King & Co., Inc. of New York, New York to aid in the
solicitation of proxies at an estimated fee of $12,500, plus reimbursement of
expenses. COMSAT may also request by telephone or telegram the return of
proxies. The extent to which this will be necessary depends entirely upon how
promptly proxies are returned. Lockheed Martin will pay the cost of SEC
registration fees related to the Lockheed Martin common stock to be issued in
the merger. The costs of printing and mailing this proxy statement/prospectus
and soliciting proxies up to $110,000 will be paid by COMSAT. Costs in excess
of this amount will be paid equally by Lockheed Martin and COMSAT.
 
   You should not send any certificates representing COMSAT common stock with
the enclosed proxy card. A letter of transmittal with instructions for the
surrender of stock certificates for COMSAT common stock will be mailed to you
as soon as practicable after the completion of the merger.
 
                                       18
<PAGE>
 
                         ITEM 1. APPROVAL OF THE MERGER
 
   This section of the proxy statement/prospectus describes the material
aspects of the proposed merger and some of the material terms of the merger
agreement. You should read the merger agreement which is attached as Appendix I
to this proxy statement/prospectus and is incorporated by reference.
 
   Based upon the capitalization of Lockheed Martin and COMSAT as of April 1,
1999, following completion of the merger, COMSAT shareholders will own between
approximately 6.4% and 8.2% of the outstanding shares of Lockheed Martin common
stock, depending on the number of shares of COMSAT common stock tendered in the
tender offer. This assumes no exercise of outstanding options to acquire
Lockheed Martin common stock or options to acquire COMSAT common stock.
 
Background of the Merger
 
   In 1997, COMSAT adopted a plan to refocus on its core strengths in
international satellite telecommunications, digital networking and technology.
As part of its plan, COMSAT decided to divest its non-core assets in
entertainment and manufacturing. In June 1997, COMSAT divested its
entertainment business, Ascent Entertainment Group, in a tax-free spin-off to
shareholders. A year later, COMSAT sold substantially all of its manufacturing
business, COMSAT RSI, and used the proceeds from the sale to pay down debt and
thereby strengthen its balance sheet. As part of its overall strategy to
enhance shareholder value, COMSAT began to consider the possibility of a
strategic alliance or business combination.
 
   As a leading provider of communications satellites, space launch vehicles,
information and communications systems, and systems integration services,
Lockheed Martin had identified in its strategic plans the global
telecommunications services market as an attractive and logical growth
opportunity. This opportunity was viewed as consistent with Lockheed Martin's
strategy to grow into closely related market sectors to enhance its core
aerospace and defense businesses. In light of the potential for expansion into
this market, Lockheed Martin periodically reviewed potential market entry
strategies, including the possibility of internal investments, joint ventures
and strategic alliances, and acquisitions and business combinations with
companies participating in the commercial telecommunications services industry.
 
   On August 5, 1997, consistent with their strategies of exploring strategic
alliances or business combinations, Lockheed Martin and COMSAT entered into
reciprocal confidentiality agreements on customary terms. On August 7 and 8,
1997, COMSAT and Lockheed Martin management met to discuss the overall market
environment of the telecommunications industry and each company's strategies
regarding that industry. They also discussed the regulatory and legislative
environment under which COMSAT operates.
 
   From August 1997 through September 1998, COMSAT management made several
presentations and reports to its Board of Directors and Strategic Planning
Committee concerning a possible business combination with Lockheed Martin. Your
Board of Directors reviewed the potential business combination with Lockheed
Martin at 10 meetings in 1997 and 1998. Your Board of Directors also asked its
Strategic Planning Committee to evaluate the potential business combination.
The Strategic Planning Committee reviewed various aspects of the proposed
transaction at 19 meetings held in 1997 and 1998.
 
   On September 25, 1997, Lockheed Martin's Board of Directors reviewed
Lockheed Martin's commercial telecommunications strategy and the strategic and
financial implications of a potential transaction with COMSAT. The Lockheed
Martin Board of Directors considered various aspects of the transaction at five
subsequent meetings in 1998.
 
   Following the initial meetings between COMSAT and Lockheed Martin
management, a series of meetings occurred over the next several weeks.
Management of both companies discussed various business, financial, structural,
legal, legislative and regulatory issues. COMSAT hired Donaldson, Lufkin &
Jenrette to act as its financial advisor in connection with the potential
business combination.
 
 
                                       19
<PAGE>
 
   COMSAT and Lockheed Martin did not reach agreement on the terms or structure
of a possible transaction after the initial series of meetings in late 1997.
Lockheed Martin then engaged outside consultants to review and suggest ways to
supplement its commercial telecommunications strategy.
 
   In early January 1998, COMSAT and Lockheed Martin met to discuss potential
alternative transaction structures within the legislative and regulatory
framework constraining COMSAT. These alternatives included structures involving
varying degrees of equity ownership of COMSAT as well as joint ventures
involving COMSAT's non-regulated businesses, including primarily COMSAT
International and COMSAT Laboratories.
 
   Meetings continued during March and early April in which the parties
discussed alternative transaction structures, the evolving regulatory and
legislative environment and the potential benefits related to a business
combination. These discussions continued through May and June 1998.
 
   On June 26, 1998, the Lockheed Martin Board of Directors reviewed the
results of a task force comprising Lockheed Martin management and outside
consultants. The task force recommended that Lockheed Martin pursue a strategy
to increase its investment in the commercial telecommunications business. On
the same day, Lockheed Martin and COMSAT and their investment bankers met to
discuss transaction structures, valuations, and potential timetables for
reaching an agreement. Over the next three weeks, Lockheed Martin and COMSAT
met to further define transaction structure and negotiate the terms of the
proposed business combination.
 
   During the week of July 27, 1998, members of management of both companies
met with outside counsel and investment bankers to continue negotiations
concerning terms of the transaction. In the ensuing weeks, negotiations
continued. As a result of significant progress toward an agreement, Lockheed
Martin and COMSAT determined to hold simultaneous board meetings on Sunday,
August 30, 1998 to seek approval of the transaction. Due to volatility and a
decline in the stock markets on August 27, 1998 and concerns related to
economic instability in parts of the world, including Russia, Asia, Central and
South America and other emerging markets, additional issues arose. In addition,
several open issues proved more difficult to address than had been anticipated.
As a result, the parties decided to postpone the board meetings.
 
   Negotiations continued and sufficient progress was made in resolving
outstanding issues to allow the parties to seek board approval on September 18,
1998 at the regularly scheduled meeting of your Board of Directors and at a
special meeting of the Lockheed Martin Board of Directors.
 
   At the September 18, 1998 meeting, COMSAT management reviewed for your Board
of Directors the status of negotiations and the principal terms of the proposed
transaction. COMSAT's general counsel reviewed the merger agreement, other
transaction documents and various legal and regulatory matters related to the
proposed transaction. Donaldson, Lufkin & Jenrette reviewed the financial
analysis and valuation it conducted on the proposed transaction and delivered
to your Board of Directors its written opinion that, as of September 18, 1998,
the consideration to be received in the tender offer and merger was fair, from
a financial point of view, to COMSAT shareholders. After receiving those
reports and advice and after reviewing additional information relating to the
transaction, your Board of Directors approved the merger agreement. The factors
your Board of Directors considered in approving the merger agreement are
summarized below.
 
   Following the meeting of the COMSAT Board of Directors, a special telephonic
meeting of the Lockheed Martin Board of Directors was held to consider the
proposed transaction. The factors the Lockheed Martin Board of Directors
considered in approving the merger are summarized below.
 
   The Lockheed Martin Board of Directors reviewed the transaction documents,
transaction structure and various legal and regulatory issues. After receiving
such advice and after reviewing various additional information relating to the
transaction, the Lockheed Martin Board of Directors approved the terms and
conditions of the transaction.
 
 
                                       20
<PAGE>
 
   Following the conclusion of the Lockheed Martin Board of Directors meeting
on the evening of September 18, 1998, Lockheed Martin and COMSAT executed the
merger agreement and the other transaction agreements and publicly announced
the merger on September 20, 1998.
 
Recommendations of the COMSAT Board of Directors; Reasons for the Merger
 
 Recommendation of the COMSAT Board of Directors.
 
   Your Board of Directors has by a unanimous vote, excluding Mr. Eagleburger
who attended the meeting but was absent when the vote was taken and Messrs.
Bennett, Colodny and Hurtt who recused themselves, approved the tender offer,
the merger and the merger agreement and determined that the terms of each of
the tender offer, the merger and the merger agreement are consistent with, and
advance, the long-term business strategy of COMSAT and are fair to COMSAT
shareholders. Your Board of Directors recommends that you vote in favor of the
merger proposal. This recommendation is based in part upon an opinion the
COMSAT Board of Directors received from Donaldson, Lufkin & Jenrette, to the
effect that, as of September 18, 1998, the consideration to be received by
COMSAT shareholders pursuant to the merger agreement was fair to such
shareholders from a financial point of view. The full text of this opinion,
which sets forth the factors considered and the assumptions made by Donaldson,
Lufkin & Jenrette, is attached to this proxy statement/prospectus as Appendix
III. See also "Item 1. Approval of the Merger--Opinion of COMSAT's Financial
Advisor." You should read the opinion.
 
 Reasons for the COMSAT Board's Recommendation.
 
   Factors Considered by the COMSAT Board of Directors. In approving the merger
and the related transactions, and recommending that you vote in favor of the
merger, the COMSAT Board of Directors considered a number of factors including:
 
     (1) the financial and other terms of the tender offer, the merger
  agreement, shareholder agreement, carrier acquisition agreement and
  registration rights agreement;
 
     (2) the presentation of Donaldson, Lufkin & Jenrette and its opinion
  that, as of September 18, 1998, the consideration to be received by COMSAT
  shareholders pursuant to the merger agreement was fair to such shareholders
  from a financial point of view;
 
     (3) that the $45.50 per share offer price to be paid for the shares in
  the tender offer represents a premium of approximately 33.5% over the $34
  1/8 closing price of COMSAT common stock on the New York Stock Exchange on
  September 18, 1998, the last full trading day prior to the execution of the
  merger agreement;
 
     (4) the absence of a financing condition to the tender offer and the
  perceived ability of Lockheed Martin, as compared to other potential
  acquirors, to obtain the regulatory approvals and legislative changes
  required to complete the tender offer, the merger and the transactions
  contemplated by the merger agreement;
 
     (5) COMSAT's future prospects, financial resources and ability to access
  the capital markets as a stand-alone enterprise;
 
     (6) proposed legislation that, if enacted, could significantly and
  adversely harm COMSAT's core businesses and the value of your investment in
  COMSAT;
 
     (7) increased competition in all segments of COMSAT's business from
  other companies with substantially greater financial resources and the
  ability of these companies to exercise greater influence over the
  legislative and regulatory process;
 
     (8) progress in efforts to privatize the International
  Telecommunications Satellite Organization ("INTELSAT") and the
  International Mobile Satellite Organization ("Inmarsat") satellite systems
  and the anticipated effects of privatization upon COMSAT, including
  potential changes in COMSAT's role as an investor and service re-seller,
  method of accounting for its investments, and future cash flows;
 
                                       21
<PAGE>
 
     (9) consolidation trends and global alliances within the satellite and
  telecommunications industries which have adversely affected, and which
  COMSAT expects will continue to adversely affect, COMSAT's relative
  competitive position;
 
     (10) the capital investment required to expand COMSAT International's
  digital networking business in emerging markets around the world and the
  limited period in which these investments must be completed to establish a
  presence in those markets in advance of competitors;
 
     (11) constraints upon COMSAT's ability to fully commercialize its
  technology assets;
 
     (12) the strategic value of COMSAT's principal assets in the hands of a
  larger enterprise, like Lockheed Martin, with the financial and other
  resources necessary to better utilize those assets;
 
     (13) the COMSAT Board of Directors' belief that the tender offer, the
  merger and the transactions contemplated by the merger agreement represent
  an opportunity to reduce certain of the risks described above by effecting
  a strategic business combination with a larger enterprise, like Lockheed
  Martin, and achieve a premium for your COMSAT common stock;
 
     (14) the expertise of Lockheed Martin in the research, manufacture and
  integration of advanced-technology satellite systems and products, and the
  opportunity to effect a strategic combination with Lockheed Martin with its
  complementary assets and telecommunications growth strategy;
 
     (15) the view of the COMSAT Board of Directors, based in part upon the
  presentation of management to the Board of Directors, that there was a
  limited likelihood of a superior offer arising under current law;
 
     (16) the provisions of the merger agreement that permit the COMSAT Board
  of Directors to consider an unsolicited superior proposal to comply with
  the COMSAT Board of Directors' fiduciary duties to COMSAT shareholders;
 
     (17) the provision of the merger agreement that permits the COMSAT Board
  of Directors to terminate the merger agreement, under specific
  circumstances, upon payment to Lockheed Martin of the $75 million
  termination fee and reimbursement of up to $5 million of Lockheed Martin's
  aggregate expenses; and
 
     (18) the ability to benefit COMSAT's customers, communications users
  around the world and employees by creating a dynamic new global competitor.
 
   The foregoing discussion of the information and factors considered and given
weight by the COMSAT Board of Directors is not intended to be exhaustive. The
preceding factors figured positively in the consideration of the merger
agreement and the merger by the COMSAT Board of Directors, with the exception
of factor (17), which the COMSAT Board of Directors considered to be neutral.
In view of the variety of factors considered in connection with its evaluation
and approval of the merger transaction, the COMSAT Board of Directors did not
find it practicable to, and did not, quantify or otherwise assign relative
weights to the specific factors considered in reaching its determination. In
addition, individual members of the COMSAT Board of Directors may have given
different weights to different factors.
 
Lockheed Martin's Reasons for the Merger
 
   In approving the merger and the related transactions, the Lockheed Martin
Board of Directors considered a number of factors, including:
 
  .  the financial condition and prospects of COMSAT;
 
  .  the strategic value of the proposed transaction and the possible effects
     of the transaction on Lockheed Martin's shareholders, operations,
     customers and future growth, and its financial condition and prospects;
     and
 
                                       22
<PAGE>
 
  .  the current state of the telecommunications industry and trends in the
     foreseeable future.
 
   Lockheed Martin's Board of Directors believes that the merger provides it
with a unique opportunity to diversify its core aerospace and defense business
and to expand its presence in the global telecommunications services market. In
particular, Lockheed Martin anticipates that:
 
  .  the merger will allow Lockheed Martin Global Telecommunications to be
     more competitive, to offer better value to its customers and to meet the
     increased demand for broadband, Internet and virtual private network
     services in the global telecommunications services market;
 
  .  the merger will allow Lockheed Martin to quickly and decisively enter
     the global telecommunications services market through COMSAT's
     established market presence;
 
  .  the COMSAT International business will present the combined company with
     significant growth opportunities as a result of COMSAT International's
     existing customers and market share in 11 high growth developing
     markets;
 
  .  COMSAT's existing relationships with many of the world's largest
     telecommunications companies, primarily through COMSAT's ownership
     shares of INTELSAT and Inmarsat, will provide Lockheed Martin with new
     opportunities for strategic alliances which may further accelerate
     growth;
 
  .  COMSAT's financial position and cash flow, as well as expected increases
     in revenues resulting from the merger, will permit increased investment
     for further growth; and
 
  .  the merger will produce positive benefits such as increases in revenue,
     increases in the number of customers, long-term growth and enhanced
     shareholder value.
 
Opinion of COMSAT's Financial Advisor
 
 Introduction.
 
   COMSAT asked Donaldson, Lufkin & Jenrette, in its role as financial advisor
to COMSAT, to render an opinion to the Board of Directors as to the fairness to
COMSAT shareholders, from a financial point of view, of the consideration to be
received by such shareholders under the merger agreement.
 
   On September 18, 1998, Donaldson, Lufkin & Jenrette delivered its written
opinion to the COMSAT Board of Directors that, as of that date and based upon
and subject to the assumptions, limitations and qualifications in the opinion,
the consideration to be received by COMSAT shareholders under the merger
agreement was fair to such shareholders from a financial point of view. A copy
of the Donaldson, Lufkin & Jenrette opinion is attached as Appendix III to this
proxy statement/prospectus. You should read this opinion for the assumptions
made, the procedures followed, the matters considered and the limits of the
review made by Donaldson, Lufkin & Jenrette.
 
   Donaldson, Lufkin & Jenrette prepared its opinion for the COMSAT Board of
Directors. The opinion addresses only the fairness from a financial point of
view of the consideration to be received by COMSAT shareholders under the
merger agreement. The opinion is not a recommendation to any COMSAT shareholder
as to how such shareholder should vote on the merger.
 
   COMSAT and Lockheed Martin determined the consideration to be paid to COMSAT
shareholders under the merger agreement in arm's length negotiations.
Donaldson, Lufkin & Jenrette advised COMSAT in the negotiations. Donaldson,
Lufkin & Jenrette was not requested to, nor did it, solicit the interest of any
other party in acquiring COMSAT.
 
   The opinion is based necessarily on economic, market, regulatory, financial
and other conditions as existed on, and on the information made available to
Donaldson, Lufkin & Jenrette as of, September 18, 1998.
 
                                       23
<PAGE>
 
Although later events may affect its opinion, Donaldson, Lufkin & Jenrette does
not have any obligation to update, revise or reaffirm its opinion. Donaldson,
Lufkin & Jenrette expressed no opinion as to:
 
  .  the prices at which the Lockheed Martin common stock would actually
     trade at any time;
 
  .  the relevant merits of the tender offer and the merger, on the one hand,
     and the other business strategies considered by the COMSAT Board of
     Directors, on the other hand; or
 
  .  the COMSAT Board of Directors' decision to proceed with such
     transactions.
 
 Information Reviewed and Assumptions Made.
 
   In arriving at its opinion, Donaldson, Lufkin & Jenrette:
 
  .  reviewed the September 18, 1998 draft of the merger agreement;
 
  .  reviewed financial and other information that was publicly available or
     that COMSAT and Lockheed Martin furnished to it, including information
     provided during discussions with their respective managements such as:
 
    .  certain financial projections of COMSAT for January 1, 1998 to
       December 31, 2002 prepared by COMSAT's management;
 
  .  compared certain financial and securities data of COMSAT with various
     other companies whose securities are traded in public markets;
 
  .  reviewed prices, premiums and multiples paid in certain other business
     combinations;
 
  .  reviewed the historical stock prices and trading volumes of the common
     stock of COMSAT and Lockheed Martin; and
 
  .  conducted such other financial studies, analyses and investigations as
     it deemed appropriate for purposes of its opinion.
 
   For its opinion, Donaldson, Lufkin & Jenrette relied upon, and assumed the
accuracy and completeness of, all the financial and other information that was
available or provided to it. Donaldson, Lufkin & Jenrette also assumed that the
financial projections provided to it were reasonably prepared on the basis
reflecting the best currently available estimates and judgments of COMSAT's
management as to the future operating and financial performance of COMSAT.
Donaldson, Lufkin & Jenrette did not make an independent evaluation of any
assets or liabilities of COMSAT or Lockheed Martin, or an independent
verification of any information Donaldson, Lufkin & Jenrette reviewed.
Donaldson, Lufkin & Jenrette assumed that the tender offer, the merger and all
other transactions contemplated by the merger agreement would be completed as
described in the merger agreement. Donaldson, Lufkin & Jenrette relied as to
certain legal matters on the advice of COMSAT's counsel. COMSAT imposed no
restrictions on Donaldson, Lufkin & Jenrette with respect to the investigations
it made or the procedures it followed in arriving at its opinion.
 
 Financial Analyses.
 
   The following is a summary of the financial analyses that Donaldson, Lufkin
& Jenrette performed in connection with its opinion and its presentation to the
COMSAT Board of Directors on September 18, 1998.
 
 COMSAT.
 
   (1) Equity Value Per Share Analysis. Donaldson, Lufkin & Jenrette calculated
the implied equity value of COMSAT by:
 
  .  adding together the enterprise values of COMSAT's business segments;
 
  .  deducting an amount for corporate overhead;
 
  .  deducting an amount for long-term debt, preferred stock and minority
     interests; and
 
  .  adding an amount for investments, other assets and cash.
 
                                       24
<PAGE>
 
   This analysis resulted in an implied equity valuation range for COMSAT of
approximately $2.1 billion to $3.1 billion in the aggregate, and approximately
$36.47 to $54.26 per share. Based upon the results of all its analyses taken as
a whole, Donaldson, Lufkin & Jenrette determined that an appropriate reference
range per share of COMSAT common stock would be $40.00 to $50.00. The table
below summarizes these results:
 
<TABLE>
<CAPTION>
                                                              Valuation Range
                                                             ------------------
                                                               Low       High
                                                             --------  --------
                                                               (In millions,
                                                             except per share
                                                                   data)
     <S>                                                     <C>       <C>
     Satellite Businesses:
     World Systems.......................................... $1,500.0  $1,950.0
     Mobile Communications..................................    500.0     725.0
     Network Businesses:
     International..........................................    650.0     850.0
     Other Businesses(1)....................................     60.0     100.0
     Corporate Overhead.....................................   (190.0)   (145.0)
                                                             --------  --------
     Total Business Segment Range........................... $2,520.0  $3,480.0
                                                             ========  ========
     Less: Long Term Debt(2)................................   (480.8)   (480.8)
     Less: Preferred Stock(2)...............................   (200.0)   (200.0)
     Less: Minority Interest(2).............................     (6.1)     (6.1)
     Plus: Investments(3)...................................    130.4     130.4
     Plus: Other Assets(4)..................................     36.0     100.0
     Plus: Cash(2)(5).......................................    100.0     100.0
                                                             --------  --------
     Equity Value........................................... $2,099.5  $3,123.5
                                                             ========  ========
     Shares Outstanding(2)(5)...............................     57.6      57.6
     Equity Value per Share................................. $  36.47  $  54.26
     Reference Range per Share.............................. $  40.00  $  50.00
</TABLE>
    --------
 
    (1) Includes COMSAT Laboratories and Government Programs; assumes a
        multiple ranging from 1.5 to 2.5 times estimated December 31, 1998
        book value.
    (2) Capitalization estimated as of December 31, 1998.
    (3) Includes the market value of ICO (direct and indirect ownership),
        Viatel and Calian, respectively; other investments carried at cost.
    (4) Includes after-tax proceeds from potential tax refund claims and
        litigation.
    (5) Includes cash proceeds of $94.3 million from exercise of in-the-
        money options. Assumes that proceeds from exercise are held in cash.
 
   Donaldson, Lufkin & Jenrette's analysis of the enterprise value of COMSAT's
three principal business units and of COMSAT's corporate overhead are described
below.
 
   World Systems Business Segment. COMSAT's World Systems business segment
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 Satellites, N.V.
Donaldson, Lufkin & Jenrette analyzed the enterprise value of the World Systems
business segment using comparable public companies analysis, comparable
acquisitions analysis and discounted cash flow analysis.
 
  .  Comparable Public Companies Analysis. Donaldson, Lufkin & Jenrette
     analyzed the enterprise value of the World Systems business segment
     based on the market values and trading multiples of three comparable
     publicly traded companies:
 
    .  PanAmSat
 
    .  Apt Satellite Holdings; and
 
    .  Asia Satellite Telecom.
 
                                       25
<PAGE>
 
     For each company, Donaldson, Lufkin & Jenrette analyzed:
 
    .  the equity value and the enterprise value as of September 15, 1998;
       and
 
    .  the enterprise value as a multiple of estimated sales and estimated
       earnings before interest, taxes, depreciation and amortization
       ("EBITDA") for calendar years 1998 and 1999.
 
    Enterprise value is defined as the equity value plus the book value of
    debt and preferred stock less cash. Equity value is defined as the
    market value of the common equity securities. The sales and EBITDA
    estimates for calendar years 1998 and 1999 were based on publicly
    available estimates from equity research analysts. From this analysis,
    Donaldson, Lufkin & Jenrette developed enterprise valuation multiples
    ranging from 5.0 to 6.5 times sales and 7.5 to 10.0 times EBITDA.
    Donaldson, Lufkin & Jenrette then applied these valuation multiples to
    1998 and 1999 projected operating data for the World Systems business
    segment as prepared by COMSAT management. The analysis resulted in an
    imputed enterprise valuation range for the World Systems business
    segment of approximately $1.3 billion to $2.1 billion. Donaldson,
    Lufkin & Jenrette believed that a valuation based on trading multiples
    of public satellite companies is difficult due to the numerous and
    significant differences among the comparable companies and the World
    Systems business segment in size, system age and types of services
    provided.
 
  .  Comparable Acquisitions Analysis. Donaldson, Lufkin & Jenrette also
     analyzed the enterprise value of the World Systems business segment
     based on the transaction multiples paid in selected comparable
     transactions. The transactions analyzed included:
 
    .  Hughes Communications' acquisition of PanAmSat;
 
    .  Loral's acquisition of SkyNet;
 
    .  Loral's acquisition of Orion Network; and
 
    .  Loral's acquisition of SatMex.
 
    For each acquisition, Donaldson, Lufkin & Jenrette analyzed:
 
    .  the total transaction value;
 
    .  the total transaction value as a multiple of revenues, EBITDA and
       earnings before interest and taxes for the twelve months prior to
       announcement of a transaction; and
 
    .  the total transaction value as a multiple of EBITDA for the current
       fiscal year and the subsequent fiscal year as of the date of
       announcement of the transaction.
 
    The EBITDA estimates for the current and subsequent fiscal years were
    based on publicly available projections from research analysts. From
    this analysis, Donaldson, Lufkin & Jenrette developed valuation
    multiples ranging from 7.0 to 10.0 times current fiscal year EBITDA and
    6.5 to 9.0 times EBITDA for the subsequent fiscal year. Donaldson,
    Lufkin & Jenrette then applied these valuation multiples to projected
    1998 and 1999 operating data for the World Systems business segment
    prepared by management. The analysis resulted in an imputed enterprise
    valuation range for the World Systems business segment of approximately
    $1.3 billion to $2.1 billion. Donaldson, Lufkin & Jenrette believed
    that its analysis of comparable transactions is of limited usefulness
    given the relatively small universe of transactions and disparities
    among the companies involved in these transactions and the World
    Systems business segment.
 
  .  Discounted Cash Flow Analysis. Donaldson, Lufkin & Jenrette also
     analyzed the enterprise value of the World Systems business segment
     using a discounted cash flow analysis based on estimates of the
     projected financial performance for such segment prepared by COMSAT
     management for the fiscal years 1999 to 2002. Utilizing these
     projections, Donaldson, Lufkin & Jenrette calculated a range of present
     values for the segment based upon the discounted net present value of
     the sum of (a) the
 
                                       26
<PAGE>
 
     projected stream of after-tax unlevered free cash flows of the segment,
     which is operating cash flow available after working capital, capital
     spending and tax requirements, to the year 2002; and (b) the projected
     terminal value of the segment at such year based upon a range of
     multiples of the segment's projected EBITDA in such year. Applying
     discount rates ranging from 10.0% to 11.5% and multiples of terminal
     EBITDA ranging from 7.5 to 9.5 times, Donaldson, Lufkin & Jenrette
     estimated enterprise values of the segment ranging from approximately
     $1.5 billion to $1.9 billion.
 
   Based on these methodologies, Donaldson, Lufkin & Jenrette determined that
an appropriate range of enterprise values for the World Systems business
segment would be $1.50 billion to $1.95 billion.
 
   Mobile Communications Business Segment. COMSAT's Mobile Communications
business segment provides satellite telecommunications services for maritime,
aeronautical and land mobile applications, primarily using the satellite
system of Inmarsat. Donaldson, Lufkin & Jenrette analyzed the enterprise value
of the Mobile Communications business segment using comparable acquisitions
analysis, discounted cash flow analysis, and a pro rata Inmarsat-based
valuation analysis.
 
  .  Comparable Acquisitions Analysis. Donaldson, Lufkin & Jenrette analyzed
     the enterprise value of the Mobile Communications business segment based
     on the transaction multiples paid in selected comparable acquisitions.
     The acquisitions and financial data analyzed were the same as for the
     World Systems business segment, as described above. Although such
     transactions involved providers of fixed satellite services, given the
     lack of comparable acquisitions involving mobile satellite service
     providers, Donaldson, Lufkin & Jenrette believed they provided a
     relevant valuation benchmark. From this analysis, Donaldson, Lufkin &
     Jenrette developed valuation multiples ranging from 7.0 to 9.0 times
     EBITDA for the current fiscal year and 6.0 to 8.0 times EBITDA for the
     subsequent fiscal year. Donaldson, Lufkin & Jenrette then applied these
     valuation multiples to projected 1998 and 1999 operating data for the
     Mobile Communications business segment prepared by management. The
     analysis resulted in an imputed enterprise valuation range for the
     Mobile Communications business segment of approximately $650 million to
     $875 million.
 
  .  Discounted Cash Flow Analysis. Donaldson, Lufkin & Jenrette also
     analyzed the enterprise value of the Mobile Communications business
     segment using a discounted cash flow analysis for three separate sub-
     segments: voice/telex services, data/aero services and contract
     services, in each case based on estimates of the projected financial
     performance for such sub-segment prepared by COMSAT management for the
     fiscal years 1999 to 2002. In the aggregate, this analysis resulted in
     an imputed enterprise valuation range for the Mobile Communications
     business segment of approximately $505 million to $720 million, as
     follows:
 
<TABLE>
<CAPTION>
                                                 Range of Perpetuity
                                                 Growth Rates of Cash  Approximate Enterprise
                              Range of Discount Flow Used to Calculate    Valuation Range
           Sub-Segment          Rates Applied       Terminal Value         (in millions)
           -----------        ----------------- ---------------------- ----------------------
     <S>                      <C>               <C>                    <C>
     Voice/Telex services....   12.0% to 13.5%    (15.0%) to (12.0%)        $180 to $200
     Data/Aero services......   14.0% to 15.5%       7.0% to 9.0%           $280 to $465
     Contract services.......   11.0% to 12.5%       0.0% to 1.0%            $45 to $55
</TABLE>
 
  .  Pro rata Inmarsat-Based Valuation Analysis. Donaldson, Lufkin & Jenrette
     also analyzed the enterprise value of the Mobile Communications business
     segment based on: (a) a valuation of the segment's pro-rata share of
     Inmarsat and (b) a discounted cash flow analysis of the segment's in-
     house operations.
 
    .  Based on Donaldson, Lufkin & Jenrette's analysis of the July 1998
       announced sale of a 1.4% ownership interest in Inmarsat by Teleglobe
       to Stratos Global, Donaldson, Lufkin & Jenrette estimated the implied
       value of the Mobile Communications business segment's ownership
       interest in Inmarsat ranging from approximately $400 million to $525
       million.
 
                                      27
<PAGE>
 
    .  Donaldson, Lufkin & Jenrette estimated the implied value of the
       segment's in-house operations based on estimates of the projected
       financial performance for such operations prepared by COMSAT
       management for the fiscal years 1999 to 2002, applying discount
       rates ranging from 13.0% to 14.5% and calculating terminal values
       based on perpetuity growth rates ranging from 1.0% to 3.0%. This
       analysis resulted in a valuation for in-house operations ranging
       from approximately $140 million to $185 million, and an overall
       enterprise valuation range for the segment of approximately $540
       million to $710 million.
 
   Based on these methodologies, Donaldson, Lufkin & Jenrette determined that
an appropriate range of enterprise values for the Mobile Communications
business segment would be $500 million to $725 million.
 
   International Network Business Segment. COMSAT's International Network
business segment provides individualized digital network solutions to business
clients and carriers in selected markets in Latin America, Asia and Europe.
Donaldson, Lufkin & Jenrette estimated the enterprise valuation of the
International Network business segment using a comparable public companies
analysis and a discounted cash flow analysis.
 
  .  Comparable Public Companies Analysis. Donaldson, Lufkin & Jenrette
     analyzed the enterprise value of the International Network business
     segment based on the market values and trading multiples of three
     publicly traded companies:
 
    .  Grupo Iusacell;
 
    .  Stet Hellas Communications; and
 
    .  Telecel.
 
    Although these companies are not directly comparable to the
    International Network business segment, Donaldson, Lufkin & Jenrette
    believed they would provide a relevant valuation benchmark. For each
    company, Donaldson, Lufkin & Jenrette analyzed:
 
    .  the equity value and the enterprise value as of September 15, 1998;
       and
 
    .  the enterprise value as a multiple of estimated sales and estimated
       EBITDA for calendar years 1998 and 1999.
 
    The sales and EBITDA estimates for calendar years 1998 and 1999 were
    based on publicly available projections from research analysts. From
    this analysis, Donaldson, Lufkin & Jenrette developed valuation
    multiples ranging from 2.5 to 6.0 times sales and 8.5 to 10.0 times
    EBITDA. Donaldson, Lufkin & Jenrette then applied these valuation
    multiples to projected 1998 and 1999 operating data for the
    International Network business segment as prepared by COMSAT
    management. Based on this analysis, Donaldson, Lufkin & Jenrette
    estimated an imputed enterprise valuation range for the International
    Network business segment of approximately $675 million to $800 million.
 
  .  Discounted Cash Flow Analysis. Donaldson, Lufkin & Jenrette also
     analyzed the enterprise value of the International Network business
     segment using a discounted cash flow analysis based on estimates of the
     projected financial performance for such segment prepared by COMSAT
     management for the fiscal years 1999 to 2002. Utilizing these
     projections, Donaldson, Lufkin & Jenrette calculated a range of present
     values for the segment based upon the discounted net present value of
     the sum of (a) the projected stream of after-tax unlevered free cash
     flows of the segment, which is operating cash flow available after
     working capital, capital spending and tax requirements, to the year
     2002; and (b) the projected terminal value of the segment at such year
     based upon a range of multiples of the segment's projected EBITDA in
     such year. Applying discount rates ranging from 15.5% to 16.5% and
     multiples of terminal EBITDA ranging from 8.0x to 10.0x, Donaldson,
     Lufkin & Jenrette estimated an imputed enterprise valuation range for
     the International Network business segment of approximately $650 million
     to $900 million.
 
   Based on these methodologies, Donaldson, Lufkin & Jenrette determined that
an appropriate range of enterprise values for the International Network
business segment would be $650 million to $850 million.
 
                                       28
<PAGE>
 
   Corporate Overhead. Donaldson, Lufkin & Jenrette reduced the combined
enterprise value of the business segments by approximately $145 million to $190
million for corporate overhead. Donaldson, Lufkin & Jenrette calculated this
amount using a discounted cash flow analysis based on estimates of the
projected corporate overhead of COMSAT prepared by COMSAT management for the
fiscal years 1999 to 2002 to which it applied discount rates ranging from 10.5%
to 11.5% and calculated terminal value by applying perpetuity growth rates
ranging from 1.0% to 3.0%.
 
   (2) Premiums Paid Analysis. Donaldson, Lufkin & Jenrette analyzed the
implied price per share of COMSAT based on a review of premiums paid in
transactions between $2 billion to $5 billion that occurred in the twelve
months prior to September 18, 1998. For each such transaction, Donaldson,
Lufkin & Jenrette analyzed the premium over the market price per share one day,
one week and one month prior to announcement. Application of average premiums
resulted in the following:
 
<TABLE>
<CAPTION>
         Period Prior to                   Implied Price Per Share
           Announcement    Average Premium     of COMSAT stock
         ---------------   --------------- -----------------------
         <S>               <C>             <C>
         one day.........       26.7%              $41.18
         one week........       33.7%              $41.60
         one month.......       37.8%              $39.02
</TABLE>
 
   (3) Stock Price and Trading History. Donaldson, Lufkin & Jenrette reviewed
the daily trading activity, including price and volume, of the COMSAT common
stock from September 13, 1996 to September 15, 1998. In addition, Donaldson,
Lufkin & Jenrette reviewed the stock prices, trading history and volatility of
other publicly-traded satellite companies.
 
 Lockheed Martin.
 
   (1) Stock Price and Trading History. Donaldson, Lufkin & Jenrette reviewed
the daily trading activity, including price and volume, of the Lockheed Martin
common stock from September 13, 1996 to September 15, 1998.
 
   (2) Relative Performance. Donaldson, Lufkin & Jenrette compared the weekly
trading performance of the Lockheed Martin stock to the Standard & Poor's
Industrials and an index of Aerospace-Defense Electronics Companies from
September 13, 1996 to September 11, 1998. Standard & Poor's Industrials is an
index which tracks the performance of the S&P 400. The Aerospace-Defense
Electronics Index includes the following aerospace/defense companies:
 
                                                  .  Northrop Grumman
     .Allied Signal
 
 
                                                  .  Raytheon
     .BE Aerospace
 
 
                                                  .  United Technologies
     .Boeing
 
     .General Dynamics
 
Such analysis indicated that historical trading performance of Lockheed Martin
was in line with other aerospace/defense peer companies.
 
   (3) Comparable Trading Analysis. Donaldson, Lufkin & Jenrette compared
Lockheed Martin to six comparable companies on the basis of equity values and
enterprise values, based on stock prices on September 15, 1998, measured as a
multiple of selected historical and projected financial data. The comparable
companies were:
 
     .Allied Signal                               .  Northrop Grumman
 
 
     .Boeing                                      .  Raytheon
 
 
     .General Dynamics                            .  United Technologies
 
 
                                       29
<PAGE>
 
This analysis indicated that Lockheed Martin traded at the median of these
comparable companies.
 
   (4) Accretion/Dilution Analysis. Donaldson, Lufkin & Jenrette analyzed the
impact of the transaction on the projected earnings per share of Lockheed
Martin for the projected fiscal years ending December 31, 1999, 2000 and 2001.
The earnings per share projections for 1999 were based on First Call estimates.
The earnings per share projections for 2000 and 2001 were based on such 1999
projections compounded by a long-term earnings per share growth rate estimated
by First Call. The pro forma earnings per share projections were calculated
assuming that Lockheed Martin acquired 49% of the COMSAT common stock in the
tender offer and the remaining 51% of the COMSAT common stock in the merger. As
set forth in the table below, this analysis indicated that the transaction was
expected to have a dilutive effect on the projected earnings per share for
Lockheed Martin for the periods indicated below, unless pre-tax savings were
realized. All per share amounts have been adjusted to reflect Lockheed Martin's
two-for-one stock split in the form of a stock dividend in December 1998.
 
<TABLE>
<CAPTION>
                                           Fiscal year ending December 31,
                                           ----------------------------------
                                              1999        2000        2001
                                           ----------  ----------  ----------
     <S>                                   <C>         <C>         <C>
     Projected Earnings Per Share......... $     3.72  $     4.10  $     4.52
     Pro Forma Earnings Per Share......... $     3.65  $     3.73  $     4.13
     Accretion/(Dilution) ($ per share)...     ($0.07)     ($0.36)     ($0.39)
     Accretion/(Dilution) (%).............      (1.8%)      (8.9%)      (8.6%)
     Required Pre-Tax Savings to Break
      Even (in millions).................. $     44.0  $    254.0  $    270.9
</TABLE>
 
   This summary is not a complete description of Donaldson, Lufkin & Jenrette's
analyses. Instead, it summarizes material elements of the presentation
Donaldson, Lufkin & Jenrette made to the COMSAT Board of Directors on September
18, 1998 in connection with the preparation of its opinion. The preparation of
a fairness opinion involves various determinations as to the most appropriate
and relevant methods of financial analysis and the application of these methods
to the particular circumstances. Therefore, such an opinion is not readily
susceptible to summary description.
 
   Each of Donaldson, Lufkin & Jenrette's analyses was carried out to provide a
different perspective on the transaction and add to the total mix of
information available. Donaldson, Lufkin & Jenrette did not form a conclusion
as to whether any individual analysis, considered by itself, supported or
failed to support an opinion as to the fairness from a financial point of view.
Rather, in reaching its conclusion, Donaldson, Lufkin & Jenrette considered the
results of the analyses in light of each other and ultimately rendered its
opinion based on the results of all these analyses taken as a whole. Donaldson,
Lufkin & Jenrette did not place particular reliance or weight on any individual
analysis, but instead concluded that its analyses, taken as a whole, supported
its determination. For this reason, Donaldson, Lufkin & Jenrette believes that
its analyses must be considered as a whole and that selecting portions of its
analyses and the factors considered by it, without considering all such
analyses and factors, could create an incomplete or misleading view of the
process underlying its opinion. The analyses performed by Donaldson, Lufkin &
Jenrette are not necessarily indicative of actual past or future results or
values, which may be significantly more or less favorable than suggested by
such analyses.
 
 Engagement Letter.
 
   COMSAT engaged Donaldson, Lufkin & Jenrette to act as its principal
financial advisor for a period of 24 months in connection with the sale, merger
or other business combination of COMSAT and other transactions. Under the
engagement letter, COMSAT paid Donaldson, Lufkin & Jenrette a retainer fee of
$350,000 on the signing of the letter and $2,000,000 on the signing of the
merger agreement. COMSAT agreed to pay Donaldson, Lufkin & Jenrette an
additional $2,000,000 upon completion of the tender offer.
 
 
                                       30
<PAGE>
 
   In the event of a COMSAT sale, COMSAT will also pay Donaldson, Lufkin &
Jenrette additional compensation in the amount of 0.35% of the aggregate value
of the COMSAT common stock outstanding or issuable upon exercise of options,
plus the amount of any debt assumed, acquired, remaining outstanding or
retired, less $4,175,000 of the amounts previously paid or to be paid to
Donaldson, Lufkin & Jenrette under the terms of the engagement letter. A COMSAT
sale will occur on the earliest of:
 
  .  the acquisition of over 50% of the outstanding COMSAT common stock
     calculated on a fully diluted basis;
 
  .  a merger or consolidation of COMSAT;
 
  .  the acquisition by another person of a significant portion of the assets
     of COMSAT representing over 50% of COMSAT's book value, as adjusted to
     exclude certain designated assets; or
 
  .  the closing of any other COMSAT sale.
 
   The aggregate value of outstanding COMSAT common stock will be determined,
in the case of the tender offer and the merger, based on the amount of cash to
be received by COMSAT shareholders in the tender offer plus the fair market
value of Lockheed Martin common stock to be received by COMSAT shareholders in
the merger. For that purpose, the fair market value of Lockheed Martin common
stock to be received in the merger will be determined based on the average of
the high and low sales prices for such stock over the five trading days
immediately prior to completion of the merger. If the tender offer and the
merger had been completed on September 18, 1998, the additional compensation to
Donaldson, Lufkin & Jenrette would have been approximately $7.6 million. The
actual amount of such additional compensation will depend upon factors such as
the number of shares tendered in the tender offer, the number of shares
outstanding immediately prior to the merger, the number of dissenting shares
and the fair market value of Lockheed Martin common stock as of the merger.
 
   COMSAT also agreed to reimburse Donaldson, Lufkin & Jenrette for out-of-
pocket expenses. In addition, COMSAT agreed to indemnify Donaldson, Lufkin &
Jenrette and related persons against various liabilities in connection with its
engagement, including liabilities under the federal securities laws. The SEC
has taken the position that such indemnification under the federal securities
laws may not be enforceable if it is found to be against public policy.
 
   COMSAT began working with Donaldson, Lufkin & Jenrette as a mergers and
acquisitions advisor in August 1997. In addition, Donaldson, Lufkin & Jenrette
has been advising COMSAT on the privatization of Inmarsat and had performed
strategic analyses for COMSAT. Donaldson, Lufkin & Jenrette has received
customary compensation for such services.
 
   The COMSAT Board of Directors selected Donaldson, Lufkin & Jenrette to act
as its financial advisor in connection with the tender offer and the merger
because Donaldson, Lufkin & Jenrette is an internationally recognized
investment banking firm with substantial expertise in the communications
industry and in mergers and acquisitions transactions. Donaldson, Lufkin &
Jenrette, as part of its investment banking services, is regularly engaged in
the valuation of businesses and securities in connection with mergers,
acquisitions, underwritings, sales and distributions of listed and unlisted
securities, private placements and valuations for corporate and other purposes.
 
Interests of COMSAT Executive Officers and Directors in the Merger
 
   As a result of the merger, executive officers of COMSAT will receive
substantial additional benefits under employment agreements, retention
incentives or employee benefit plans. In addition, non-employee director stock
options will vest upon completion of the merger. For this reason, the interests
of these persons in the merger may be different from or in addition to and
greater than yours and which may be conflicts of interest.
 
 
                                       31
<PAGE>
 
   In connection with the merger, COMSAT entered into the following agreements
and took the following actions:
 
  .  amended its employment agreements with Betty C. Alewine, Allen E. Flower
     and Warren Y. Zeger;
 
  .  adopted the Retention Bonus Plan;
 
  .  amended the Change in Control Severance Plan;
 
  .  amended
 
     (a) the 1990 and 1995 Key Employee Stock Plans,
 
     (b) the Non-Employee Directors Stock Plan, and
 
     (c) the Directors and Executives Deferred Compensation Plan; and
 
  .  adopted resolutions of the Board of Directors stating that the merger
     and related transactions would not be a "change in control" under other
     COMSAT employee benefit plans.
 
 Amendments to Employment Agreements.
 
   On September 18, 1998, COMSAT amended the employment agreements of Mrs.
Alewine and Messrs. Flower and Zeger to provide that, following a change in
control, the term of each employment agreement will automatically end on the
third anniversary of the change in control. The employment agreements were also
amended to provide that, with respect to the merger, a change in control will
occur upon the completion of the merger, but not on the signing of the merger
agreement, the approval of the COMSAT Board of Directors or shareholders of the
merger or the completion of the tender offer.
 
   For a description of these employment agreements and the September 18, 1998
amendments, see "Item 2. Election of Directors--Executive Compensation--
Agreements with Current Executive Officers."
 
 Retention Bonus Plan.
 
   Effective September 18, 1998, COMSAT adopted the Retention Bonus Plan. For a
description of the Retention Bonus Plan, see "Item 2. Election of Directors--
Executive Compensation--Retention Bonus Plan."
 
 Amended and Restated Change in Control Severance Plan.
 
   Effective September 18, 1998, COMSAT amended and restated the COMSAT
Corporation Change in Control Severance Plan. For a description of these
amendments and the severance plan, see "Item 2. Election of Directors--
Executive Compensation--Change in Control Severance Plan."
 
 Amendments to COMSAT Stock and Deferred Compensation Plans.
 
   Effective September 18, 1998, COMSAT amended the 1990 Key Employee Stock
Plan, the 1995 Key Employee Stock Plan and the Non-Employee Directors Stock
Plan. The amendments to each of these plans conformed the definition of change
in control to the definition described above under the caption "Amendments to
Employment Agreements." As amended, the completion of the merger will
constitute a change in control of COMSAT, resulting in the acceleration of
vesting and the exercisability of all stock options, restricted stock and other
awards outstanding under these plans.
 
   Effective September 18, 1998, COMSAT amended the Directors and Executives
Deferred Compensation Plan to provide that, if the plan is terminated, each
participant will be paid the full account balance in accordance with the plan
and the participant's elections under the plan.
 
 
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<PAGE>
 
 Board Resolutions Regarding Change in Control Provisions Under Other COMSAT
 Plans.
 
   The COMSAT Board of Directors has the authority to determine that the change
in control provisions in COMSAT benefit plans will not apply to a particular
transaction. Pursuant to this authority, the COMSAT Board of Directors has
adopted resolutions determining that the merger will not constitute a change in
control of COMSAT for the Insurance and Retirement Plan for Executives, the
Directors and Executives Deferred Compensation Plan, the Split Dollar Life
Insurance Plan for Directors and the Split Dollar Life Insurance Plan for Key
Employees.
 
 Summary of Amounts Payable as a Result of the Merger.
 
   This section summarizes the additional compensation that may be payable to
COMSAT's named executive officers and directors as a result of the merger, or
that may be payable earlier than would otherwise be the case. We have
calculated these payments based upon each executive officer's base salary and
target bonus on April 1, 1999. Actual payments will be based upon each
executive officer's highest base salary and highest target bonus for the
relevant period.
 
   Retention Bonuses. Mrs. Alewine and Messrs. Flowers and Zeger are eligible
to receive retention bonuses under the terms of their amended employment
agreements, and Mr. Mattingly and Dr. Pontano are eligible to receive retention
bonuses under the terms of the Retention Bonus Plan, as follows:
 
  .  a first bonus if the executive remains employed by COMSAT through the
     completion of the merger, the termination of the merger agreement, or
     September 18, 2000, whichever comes first, in the following amounts:
     Mrs. Alewine, $1,466,250; Mr. Flower, $652,500; Mr. Zeger, $742,500;
     Mr. Mattingly, $247,500; and Dr. Pontano, $160,500; and
 
  .  a second bonus if the executive remains employed by COMSAT through the
     eighteen month anniversary of the completion of the merger, in the
     following amounts: Mrs. Alewine, $977,500; Mr. Flower, $435,000; Mr.
     Zeger, $495,000; Mr. Mattingly, $495,000; and Dr. Pontano, $321,000.
 
   Severance Payments. Mrs. Alewine and Messrs. Flowers and Zeger are eligible
to receive severance payments under the terms of their amended employment
agreements, and Mr. Mattingly and Dr. Pontano are eligible to receive severance
payments under the terms of the Retention Bonus Plan, as follows:
 
  .  a pre-closing severance payment in an amount equal to the first
     retention bonus described above if, prior to the first retention bonus
     payment date, COMSAT terminates the executive's employment for reasons
     other than for cause or the executive's employment is terminated on
     account of disability or death, or if the executive terminates
     employment for good reason. An executive cannot receive both a pre-
     closing severance payment and the first retention bonus; and
 
  .  a post-closing severance payment in an amount equal to the second
     retention bonus described above if, after the completion of the merger
     but prior to the second retention bonus payment date, COMSAT terminates
     the executive's employment for reasons other than for cause or the
     executive's employment terminates on account of disability or death, or
     if the executive terminates employment for good reason. An executive
     cannot receive both the post-closing severance payment and the second
     retention bonus.
 
   In addition, following the merger, Mrs. Alewine and Messrs. Flower and Zeger
each will have a three-year term under their employment agreements. As salary
and targeted bonus in each of the three years, Mrs. Alewine would be eligible
to receive $977,500, Mr. Flower $435,000 and Mr. Zeger $495,000. The salary and
targeted bonus amounts will be paid if:
 
  .  the executive remains employed by COMSAT and the bonus targets are met
     to the maximum extent,
 
  .  COMSAT terminates the executive's employment for reasons other than for
     cause,
 
  .  the executive becomes disabled, or
 
  .  the executive terminates employment for good reason.
 
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<PAGE>
 
   Under the Amended and Restated Change in Control Severance Plan, if, during
the eighteen-month period following the merger, COMSAT terminates the
employment of Mr. Mattingly or Dr. Pontano for reasons other than for cause or
disability, or if the executive terminates employment for good reason, then Mr.
Mattingly would receive severance payments of $495,000 for each of two years
and Dr. Pontano would receive severance payments of $321,000 for each of two
years. However, the executive cannot receive payments following termination
under both the Amended and Restated Change in Control Severance Plan and the
Retention Bonus Plan. The executive will receive the highest benefit payable
under the two plans.
 
   Accelerated Options and Stock Awards. At the completion of the merger,
unvested stock options, restricted stock awards and restricted stock units will
vest and will become exercisable. COMSAT's named executive officers and non-
employee directors would receive the following amounts as a result of the
vesting of these options and other stock awards: Mrs. Alewine, $4,849,586; Mr.
Flower, $1,821,993; Mr. Mattingly, $1,153,318; Dr. Pontano, $751,801; Mr.
Zeger, $1,843,539; and each non-employee director, $55,637, except for Ms.
Turner and Messrs. Bennett, Schafran and Wyser-Pratte, who would each receive
$26,212. These amounts are based on the number of unvested options or other
stock awards held by each individual as of April 1, 1999 and assume that these
options and stock awards are converted into equivalent Lockheed Martin options
and stock awards, that the price of Lockheed Martin common stock on the day of
the merger is equal to $43.44, the closing price of Lockheed Martin common
stock on May 7, 1999, and that the options are exercised on that day for a net
value equal to the difference between the $43.44 price and the exercise price
of the options. The actual amount that will be received by each individual as a
result of the vesting of options and other stock awards upon the completion of
the merger may be higher or lower depending on the actual price of Lockheed
Martin common stock on the date of the merger.
 
   Retirement Benefits. At the closing of the merger, Mrs. Alewine and Messrs.
Flower and Zeger will become eligible to begin receiving benefits under the
COMSAT Insurance and Retirement Plan for Executives, without any actuarial
reduction for early commencement of benefits, on the later of the first day of
the next calendar month after reaching age 55 or the first day of the next
calendar month after termination of employment and payment of any severance
benefits. Assuming Mrs. Alewine and Messrs. Flower and Zeger begin receiving
these benefits on the first day of the next calendar month after reaching age
55, the present value of eliminating the actuarial reduction for early
commencement is estimated to be as follows: Mrs. Alewine, $1,828,360; Mr.
Flower, $419,000; and Mr. Zeger, $423,280. COMSAT calculated these present
values using the actuarial assumptions it usually applies to COMSAT retirement
plans.
 
   Parachute Tax Gross-Up. If the payments received by a COMSAT executive
officer as a result of the change in control, but not including compensation
for regular services, plus the value of accelerated stock options and awards,
exceed three times the officer's "Base Amount," he or she may owe an excess
parachute excise tax. Section 280G of the Internal Revenue Code defines Base
Amount as an officer's average annual compensation during the five previous tax
years. The excess parachute excise tax equals 20% of the amount by which the
change in control payments exceed one times the Base Amount. COMSAT will
reimburse an executive officer for this excise tax, plus any income taxes and
excise taxes owed as a result of this reimbursement. While it is difficult to
estimate the amount of parachute tax gross-up payments, the payments could be
substantial.
 
 Indemnification of Persons in the Merger.
 
   Other contracts, agreements, arrangements and understandings between COMSAT
and its directors, executive officers and affiliates are described under the
caption "The Merger Agreement--Directors' and Officers' Insurance;
Indemnification."
 
 Potential Conflicts of Interest.
 
   Marcus C. Bennett and Caleb B. Hurtt, each a director of Lockheed Martin,
also serve on the COMSAT Board of Directors. In August 1997, Mr. Bennett joined
the COMSAT Board of Directors and serves on its
 
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<PAGE>
 
Finance Committee and on its Committee on Audit, Corporate Responsibility and
Ethics. In May 1996, Mr. Hurtt joined the COMSAT Board of Directors and serves
on its Committee on Compensation and Management Development as Chairman and on
its Nominating and Corporate Governance Committee. As of April 1, 1999, Mr.
Bennett held options to purchase 4,961 shares of COMSAT common stock, of which
2,480 are currently exercisable or will be exercisable within sixty days. As of
April 1, 1999, Mr. Hurtt held 1,000 shares of COMSAT common stock and options
to purchase 9,922 shares of COMSAT common stock, of which 7,441 are currently
exercisable or will be exercisable within sixty days. Both Mr. Bennett and Mr.
Hurtt have elected to defer receipt of annual retainer fees and instead have
received phantom stock units, which are not included in their beneficial
ownership of COMSAT common stock. As of April 1, 1999, Mr. Bennett's account
held a balance of 2,016 phantom stock units and Mr. Hurtt's account held a
balance of 2,788 phantom stock units. As of April 1, 1999, Mr. Bennett and Mr.
Hurtt have beneficial ownership of 197,092 and 5,672 shares of Lockheed Martin
common stock, respectively. Mr. Bennett also has an account in a Lockheed
Martin deferred compensation plan credited with 861 phantom stock units as of
April 1, 1999. Mr. Hurtt has a similar account in a Lockheed Martin deferred
compensation plan credited with 1,013 phantom stock units as of April 1, 1999.
To avoid any actual or perceived conflict of interest, each of Mr. Bennett and
Mr. Hurtt recused himself from the deliberations relating to the merger
conducted by both Boards of Directors. Messrs. Bennett and Hurtt currently
serve on the COMSAT Board of Directors in their individual capacities and not
as representatives of Lockheed Martin. It is anticipated that, following the
tender offer, Messrs. Bennett and Hurtt will serve as two of the three
directors on the COMSAT Board of Directors which Lockheed Martin will be
entitled to designate under the shareholders agreement.
 
   Edwin I. Colodny, Chairman of the COMSAT Board of Directors and a former
member of Lockheed Martin's Board of Directors, owns 4,204 shares of Lockheed
Martin common stock. To avoid any actual or perceived conflict of interest, Mr.
Colodny recused himself from the deliberations relating to approval of the
merger and related transactions conducted by COMSAT.
 
   Lockheed Martin has a continuing engagement with the law firm of Wunder,
Knight, Levine, Thelen & Forscey to provide general legislative support. Under
this engagement, Peter S. Knight, a Presidentially-appointed director of COMSAT
since September 1994 and partner of Wunder Knight, has rendered services to
Lockheed Martin. Lockheed Martin paid Wunder Knight $161,669, $112,129,
$135,325 and $151,370 for services rendered and expenses incurred during 1998,
1997, 1996 and 1995, respectively.
 
   Lockheed Martin also has a continuing engagement with the law firm of
Manatt, Phelps & Phillips, LLP to provide general legal and legislative
advocacy services in connection with government contracts and contracting
opportunities in the state of California. Under this engagement, Charles T.
Manatt, a Presidentially-appointed director of COMSAT since May 1995 and
chairman of Manatt Phelps, has not rendered any services to Lockheed Martin.
Lockheed Martin paid Manatt Phelps $65,414, $116,113, $153,126 and $66,686 for
services rendered and expenses incurred during 1998, 1997, 1996 and 1995,
respectively.
 
   Standard Technology, Inc., a technology, engineering and systems integration
firm, has provided services to Lockheed Martin under various contracts, which
resulted from arm'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 April 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
 
                                       35
<PAGE>
 
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.
 
Accounting Treatment
 
   Lockheed Martin will account for the merger under the purchase method of
accounting in accordance with generally accepted accounting principles. Under
the purchase method, Lockheed Martin will allocate the purchase price,
including costs incurred by Lockheed Martin directly related to the merger, to
the assets acquired and liabilities assumed based upon their estimated fair
values as of the date of the completion of the merger, with any excess purchase
consideration allocated to cost in excess of net assets acquired and amortized.
The operating results of COMSAT will be included with those of Lockheed Martin
from the date of completion of the merger. See "Unaudited Pro Forma Combined
Condensed Financial Information."
 
Material U.S. Federal Income Tax Consequences
 
   In the opinion of King & Spalding and Skadden, Arps, Slate, Meagher & Flom
LLP, the following discussion is a summary of the material U.S. federal income
tax consequences of the merger to COMSAT shareholders who hold shares of COMSAT
common stock as capital assets. The following discussion may not address all of
the U.S. federal income tax consequences that may be relevant to particular
shareholders in light of their individual circumstances or to shareholders who
are subject to special rules under the Internal Revenue Code, including foreign
holders, financial institutions, tax exempt organizations, insurance companies,
dealers in securities or currencies, persons who hold their shares as a hedge
against currency risk, holders who acquired their shares as part of a straddle,
synthetic security, conversion transaction or other integrated investment,
employee benefit plans, and holders who acquired their shares as a result of
the exercise of employee stock options or otherwise as compensation. The
following summary is not binding upon the Internal Revenue Service, and is
based upon laws, regulations, rulings and decisions currently in effect, all of
which are subject to change, retroactively or prospectively. We will not seek a
ruling from the Internal Revenue Service concerning the tax consequences of the
merger. We do not know if future legislation, regulations, administrative
rulings or court decisions would alter the U.S. federal income tax consequences
discussed below. If you have questions about the material U.S. federal income
tax consequences of the tender offer, please see Lockheed Martin's Schedule
14D-1 filed with the SEC on September 25, 1998.
 
 Preliminary Considerations.
 
 
  Integration of the Tender Offer and the Merger. Lockheed Martin intends to
treat the tender offer and the merger as a single integrated transaction for
U.S. federal income tax purposes. As discussed below, the U.S. federal income
tax consequences to a COMSAT shareholder who receives shares of Lockheed Martin
common stock in the merger may differ depending upon whether the tender offer
and the merger are treated as a single integrated transaction or as two
separate transactions for U.S. federal income tax purposes. Notwithstanding
Lockheed Martin's intention to treat the tender offer and the merger as a
single integrated transaction, because the issue is not free from doubt, you or
your tax advisor may determine otherwise and treat the tender offer and merger
as two separate transactions.
 
  Tax Opinions as a Condition to the Forward Merger. The merger will be
structured as a forward merger of COMSAT with a wholly-owned subsidiary of
Lockheed Martin if certain conditions are met, including the receipt by
Lockheed Martin of a legal opinion from its tax counsel, King & Spalding, and
the receipt by COMSAT of a legal opinion from its tax counsel, Skadden, Arps,
Slate, Meagher & Flom LLP, each substantially to the effect that the merger
will constitute a reorganization within the meaning of Section 368(a) of the
Internal Revenue Code for U.S. federal income tax purposes. The issuance of the
tax opinions will depend on the facts as they exist at the time of the merger,
and the tax opinions will be based on certain factual assumptions and on
representations that are customary for transactions similar to the tender offer
and the merger. If any of those factual assumptions or representations is or
becomes inaccurate, the tax opinions would not be an appropriate basis for your
tax position or for the preparation of your tax return. The tax opinions will
not be binding upon the Internal Revenue Service or the courts.
 
                                       36
<PAGE>
 
   If these tax opinions are not received, or if any of the other conditions to
the forward merger are not satisfied, then the merger will be structured as a
reverse merger of a wholly-owned subsidiary of Lockheed Martin with COMSAT. If
the merger is completed as a reverse merger, Lockheed Martin intends to treat
the merger as not being a reorganization within the meaning of Section 368(a)
of the Internal Revenue Code, in which case the receipt of Lockheed Martin
common stock in the merger would be taxable to you and you would receive a Form
1099-B for the Lockheed Martin common stock you receive.
 
 Tax Consequences to You if the Tender Offer and the Forward Merger are Treated
as a Single Integrated Transaction.
 
  Exchange of Shares of COMSAT Common Stock Solely Pursuant to the Forward
Merger. If you surrender all of your shares of COMSAT common stock solely in
exchange for shares of Lockheed Martin common stock in the forward merger, and
you do not exchange any shares of COMSAT common stock for cash in the tender
offer, you will not recognize any gain or loss upon the exchange. You will
recognize gain or loss, however, to the extent you receive cash in the merger
instead of a fractional share of Lockheed Martin common stock, as discussed
below under the heading "Cash Received Instead of a Fractional Share of
Lockheed Martin Common Stock." The aggregate adjusted tax basis in the shares
of Lockheed Martin common stock you receive in the merger will be equal to your
aggregate adjusted tax basis in the shares of COMSAT common stock you surrender
in the merger. Your holding period for the shares of Lockheed Martin common
stock you receive in the merger will include your holding period for the shares
of COMSAT common stock you surrender in the merger.
 
  Exchange of Shares of COMSAT Common Stock in the Tender Offer and the Forward
Merger. If the tender offer and the forward merger are treated as a single
integrated transaction and you surrender some of your shares of COMSAT common
stock in exchange for cash in the tender offer and the remainder of your shares
of COMSAT common stock in exchange for shares of Lockheed Martin common stock
in the merger, you will not recognize loss but will recognize gain, if any, in
an amount equal to the lesser of:
 
     (1) the excess, if any, of the sum of the amount of cash you receive in
  the tender offer and the fair market value of the shares of Lockheed Martin
  common stock you receive in the merger over your adjusted tax basis in the
  shares of COMSAT common stock you surrender in the tender offer and the
  merger, or
 
     (2) the amount of cash you receive in the tender offer.
 
   If you receive a combination of cash and shares of Lockheed Martin common
stock in the tender offer and the forward merger, it is anticipated that, in
most circumstances, any gain you recognize will be treated as capital gain.
However, if your receipt of the cash has the effect of a dividend distribution
for U.S. federal income tax purposes, your recognized gain will be treated as
ordinary dividend income. The analysis of whether your receipt of cash has the
effect of a dividend distribution is based on very complicated rules and will
depend on your particular circumstances. You should consult your own tax
advisors for a full understanding of these rules and the tax consequences to
you of the receipt of cash in the transaction.
 
   If you exchange your shares of COMSAT common stock for a combination of cash
and Lockheed Martin common stock in the tender offer and the forward merger,
your aggregate adjusted tax basis in the shares of Lockheed Martin common stock
you receive will be the same as your aggregate adjusted tax basis in the shares
of COMSAT common stock you surrender in the tender offer and the merger,
decreased by the amount of cash you receive and increased by the amount of gain
you recognize, if any, including any portion of that gain which is treated as a
dividend. Your holding period for the shares of Lockheed Martin common stock
you receive in the merger will include your holding period for the shares of
COMSAT common stock you surrender in the merger.
 
  Cash Received Instead of a Fractional Share of Lockheed Martin Common
Stock. If you currently own a fractional share of COMSAT common stock, you will
receive cash in the merger in exchange for your
 
                                       37
<PAGE>
 
fractional COMSAT share instead of a fractional share of Lockheed Martin common
stock. You will be treated as having received the cash in redemption of the
fractional share, and you will recognize gain or loss in an amount equal to the
difference between the amount of cash you receive for the fractional share and
the portion of your adjusted tax basis in your shares of COMSAT common stock
allocable to the fractional share.
 
 Tax Consequences to You if the Tender Offer and the Forward Merger are Treated
as Separate Transactions.
 
   If, notwithstanding Lockheed Martin's intended treatment of the tender offer
and the merger, the tender offer and the forward merger are not integrated and
instead are treated as separate transactions for U.S. federal income tax
purposes, the forward merger will qualify as a reorganization within the
meaning of Section 368(a) of the Internal Revenue Code. In such case, you will
not recognize any gain or loss on the exchange of your shares of COMSAT common
stock for shares of Lockheed Martin common stock received in the merger. You
will recognize gain or loss, however, to the extent you receive cash instead of
a fractional share of Lockheed Martin common stock, as discussed above under
the heading "Cash Received Instead of a Fractional Share of Lockheed Martin
Common Stock." The aggregate adjusted tax basis in the Lockheed Martin common
stock you receive in an exchange pursuant to the merger will be equal to your
aggregate adjusted tax basis in the shares of COMSAT common stock you surrender
in the merger. Your holding period for the shares of Lockheed Martin common
stock you receive in the merger will include your holding period for the shares
of COMSAT common stock you surrender in the merger.
 
 Tax Consequences to You if the Merger is Effected as a Reverse Merger.
 
  Tender Offer and Reverse Merger as an Integrated Transaction. If the tender
offer and the merger are integrated and the merger is effected as a reverse
merger, Lockheed Martin intends to treat the reverse merger as not qualifying
as a reorganization within the meaning of Section 368(a) of the Internal
Revenue Code. As a result, your receipt of cash in the tender offer and shares
of Lockheed Martin common stock pursuant to the reverse merger will constitute
a sale or exchange upon which you will recognize gain or loss, and a Form 1099-
B will be issued to you. The amount of the gain or loss you will recognize will
equal the difference between the sum of the amount of cash and the fair market
value of the shares of Lockheed Martin common stock you receive and your
adjusted tax basis in the shares of COMSAT common stock you surrender in the
tender offer and the merger.
 
  Tender Offer and Reverse Merger as Separate Transactions. If, notwithstanding
Lockheed Martin's intended treatment of the tender offer and the merger, the
tender offer and the merger are not integrated, and instead are treated as
separate transactions for U.S. federal income tax purposes, and the merger is
effected as a reverse merger, the reverse merger may qualify as a
reorganization within the meaning of Section 368(a) of the Internal Revenue
Code, in which case the treatment would be the same as discussed above under
the heading "Tax Consequences to You if the Tender Offer and the Forward Merger
are Treated as Separate Transactions."
 
 Characterization of Gain or Loss.
 
   The gain or loss, if any, you recognize in the merger will be capital gain
or loss. If, as of the date of the merger, you have held the shares of COMSAT
common stock you surrender for more than one year, that capital gain will be
long-term. The amount of any gain or loss you recognize and its character as
short-term or long-term will be calculated and determined separately for each
identifiable block of shares of COMSAT common stock you surrender in the
merger.
 
 Tax Consequences to COMSAT of the Merger.
 
   While the tax consequences of the tender offer and the merger to you depend
on the structure and characterization of the transactions, under any structure
or characterization of the transactions, COMSAT will not recognize gain or loss
as a result of the merger.
 
                                       38
<PAGE>
 
   You are urged to consult your own tax advisors to determine the specific tax
consequences to you of the merger, including any federal, state, local, foreign
or other tax consequences, and any tax return filing or other tax reporting
requirements.
 
Regulatory Approvals
 
   Antitrust.
 
   Under the HSR Act and the rules of the Federal Trade Commission and the
Department of Justice, the tender offer and the merger may not be completed
unless specific information has been furnished to the Department of Justice and
the Federal Trade Commission and waiting period requirements have been
satisfied.
 
   The Federal Trade Commission has informed Lockheed Martin that it intends to
consider the merger of COMSAT Government Systems with Regulus, the tender offer
and the merger as a single integrated merger transaction, requiring Lockheed
Martin and COMSAT to each file only one notification and report form for the
entire transaction. On November 17, 1998, Lockheed Martin and COMSAT each filed
the required notification and report forms for the merger and related
transactions with the Federal Trade Commission and the Department of Justice.
The Department of Justice has asserted jurisdiction over the matter and is
reviewing the transaction. As a result of these filings, the waiting period was
scheduled to expire on December 17, 1998. On December 17, 1998, Lockheed Martin
and COMSAT each received requests for additional information from the
Department of Justice extending the waiting period until the 20th calendar day
after Lockheed Martin and COMSAT substantially comply with the requests, unless
they otherwise resolve the matter with the Department of Justice and thereby
terminate the waiting period. Lockheed Martin and COMSAT have furnished
additional information to the Department of Justice, but have not substantially
complied with the request for additional information. After Lockheed Martin and
COMSAT substantially comply with the requests for additional information, the
waiting period may be extended only by court order.
 
   Lockheed Martin has negotiated terms with the Department of Justice which
could form the basis of a consent order that would resolve the Department of
Justice's review process. The most significant term negotiated is that any
consent order would require the divestiture of Lockheed Martin's interest in
Loral Space & Communications Ltd. over a two-year period after the tender offer
is completed. Lockheed Martin has stated that a condition to its willingness to
enter into such a consent order is that Lockheed Martin must obtain binding
assurances from Loral Space satisfactory to Lockheed Martin that Loral Space
will support Lockheed Martin's proposed divestiture on the terms and conditions
and within the time periods required by any consent order, including but not
limited to, by making any required filings with the SEC. We do not know when or
if Lockheed Martin will reach definitive agreements with the Department of
Justice or Loral Space. Further, if such agreements are reached, the consent
order reflecting these agreements must be approved by a federal district court.
We do not know whether this will occur.
 
   As a result of the merger, Lockheed Martin will acquire COMSAT's minority
equity interests in New Skies Satellites, N.V. and Inmarsat. It is likely that
Lockheed Martin will be required to file separate notification and report forms
with respect to these acquisitions prior to completing the merger.
 
   Lockheed Martin or COMSAT may agree to not close the merger, even if the
waiting period were to expire, to allow the Department of Justice additional
time to review the transaction. In addition, the merger agreement provides that
Lockheed Martin is not required to agree to divest any of its businesses or
assets or agree to any other restrictions if the Lockheed Martin Board of
Directors determines in good faith that such agreement is not in the best
interests of Lockheed Martin. Lockheed Martin will not complete the tender
offer
 
                                       39
<PAGE>
 
unless and until the waiting period requirements imposed by the HSR Act have
expired or been terminated. If any of the transactions contemplated by the
merger agreement have not occurred within one year after the HSR Act waiting
period expires or is terminated, Lockheed Martin and COMSAT must re-file
notification and report forms with the Federal Trade Commission and the
Department of Justice with respect to the transactions that have not been
completed in the one-year period, and a new HSR Act waiting period and review
process will begin from the date the filings are made.
 
   At any time before or after the completion of the tender offer or the
merger, the Federal Trade Commission or the Department of Justice can challenge
the tender offer or the merger and take any action under the antitrust laws as
either deems necessary or desirable in the public interest. Private parties and
state attorneys general may also bring legal action under federal or state
antitrust laws under certain circumstances.
 
   In September and October of 1998, Lockheed Martin and COMSAT analyzed
whether the merger and related transactions required pre-merger filings under
the European Union's merger notification regulations. Under the regulations, a
pre-merger filing is required if each of the parties derives revenues from
sales in the European Union in excess of certain thresholds. Based on their
analysis, Lockheed Martin and COMSAT determined that although Lockheed Martin's
revenues from sales in the European Union were sufficient to require a filing,
COMSAT's revenues were not. As a result, the parties did not make a European
Union pre-merger filing.
 
   On April 13, 1999, the European Commission's Merger Task Force sent a letter
to Lockheed Martin Global Telecommunications requesting information to enable
the Merger Task Force to evaluate whether the merger and related transactions
required a pre-merger filing. Lockheed Martin and COMSAT have gathered the data
necessary to respond to this letter, and, after reviewing this additional data,
remain of the opinion that a European Union pre-merger filing is not required.
 
   Pre-merger filings are required in Germany and Turkey, and Lockheed Martin
and COMSAT are currently preparing these filings. In addition, a post-merger
filing is required in Brazil.
 
   FCC Approvals.
 
   Before the tender offer can close, Regulus must become a common carrier and
be authorized by the FCC to acquire a non-controlling interest of up to 49% of
COMSAT common stock as an authorized carrier. To facilitate Regulus becoming an
authorized carrier, Lockheed Martin and COMSAT have entered into the carrier
acquisition agreement which provides for the merger of COMSAT Government
Systems into Regulus. As a result of this merger, Regulus will succeed to
COMSAT Government Systems' FCC common carrier authorizations.
 
   The FCC must approve the transfer of control of COMSAT Government Systems
before its merger with Regulus can occur. The FCC must also authorize Regulus
to acquire a non-controlling interest of up to 49% of COMSAT common stock as an
authorized carrier. On October 16, 1998, Lockheed Martin, Regulus and COMSAT
filed the relevant applications with the FCC. The FCC requires that the parties
show that the grant of the applications is consistent with the public interest,
convenience and necessity and that the applicant is qualified to hold these
licenses and authorizations. A number of competitors of COMSAT and other
communications common carriers have filed petitions with the FCC in opposition
to these applications or petitions to impose conditions on the grant of the
applications which could have a significant adverse effect on COMSAT.
 
   Lockheed Martin expects that, following the amendment of the Satellite Act,
Lockheed Martin, Regulus and COMSAT will be required to apply to the FCC for
the authority to transfer control of COMSAT, in a
 
                                       40
<PAGE>
 
process similar to the applications submitted by Lockheed Martin and Regulus
with respect to the transfer of control of COMSAT Government Systems. This
process generally takes several months. The precise nature of any approval
requirement will, however, depend upon the details of any amendment to the
Satellite Act. We do not know when or if the relevant provisions of the
Satellite Act will be amended, or when or if the requisite FCC approvals will
be obtained to permit the completion of the merger.
 
   Satellite Act Amendment.
 
   Until Congress amends the Satellite Act, no one may own more than 50% of the
outstanding shares of COMSAT common stock. The Satellite Act provides that only
those common carriers that are authorized carriers may, in the aggregate, own a
maximum of 50% of the outstanding shares of COMSAT common stock and that no
shareholder or group of shareholders, other than an authorized carrier, may own
more than 10% of the outstanding shares of COMSAT common stock. The Satellite
Act also provides that, upon application to the FCC, and after notice and
hearing, the FCC may compel any authorized carrier that owns shares of COMSAT
common stock to transfer to the applicant, for fair and reasonable
consideration, the number of shares that the FCC determines will advance the
public interest and the purposes of the Satellite Act.
 
   In addition, until the amendment of the Satellite Act, Lockheed Martin and
Regulus are prohibited from voting the shares of COMSAT common stock acquired
in the tender offer for more than three candidates for the COMSAT Board of
Directors. It is anticipated that Messrs. Bennett and Hurtt, each of whom is on
Lockheed Martin's Board of Directors, and each of whom also currently serves on
COMSAT's Board of Directors in an individual capacity and not as a
representative of Lockheed Martin, will serve as two of these three candidates.
The Satellite Act states that the COMSAT Board of Directors must consist of 15
persons, 12 of whom are elected annually by COMSAT shareholders and three of
whom are appointed for three-year terms by the President of the United States,
with the advice and consent of the Senate. The Satellite Act also provides that
authorized carriers may separately elect up to six directors depending on the
amount of COMSAT common stock held by the authorized carriers. However, if
authorized carriers are entitled to separately elect directors, no single
authorized carrier may vote for more than three directors.
 
   Lockheed Martin and COMSAT have agreed to use all reasonable efforts to seek
the amendment of the Satellite Act and any other applicable law that would
prohibit or limit the ability of Lockheed Martin to:
 
  .  acquire and own the securities of COMSAT,
 
  .  appoint all of the officers and directors of COMSAT following the
     merger, and
 
  .  complete the transactions contemplated by the merger agreement.
 
   On February 4, 1999, Senator Conrad Burns, Chairman of the Senate Commerce
Subcommittee on Communications, introduced satellite legislation entitled
"Open-market Reorganization for the Betterment of International
Telecommunications (ORBIT) Act" (S. 376). The proposed ORBIT legislation would:
 
  .  repeal the ownership restrictions on COMSAT common stock upon enactment,
 
  .  prohibit government-imposed cancellation of COMSAT's customer contracts,
     and
 
  .  eliminate any privilege or immunity enjoyed by COMSAT based on its
     status as signatory to INTELSAT for actions after the date of enactment,
     except for actions taken by COMSAT upon instruction of the U.S.
     government or due to treaty obligations.
 
 
                                       41
<PAGE>
 
   The proposed ORBIT legislation also would establish as U.S. policy the goal
of privatization of INTELSAT no later than January 1, 2002, and would prohibit
INTELSAT from direct access to the U.S. retail market or providing direct-to-
home/direct broadcast satellite services, digital audio radio services and
certain
other satellite services until after privatization. If the January 1, 2002
privatization target were not met, the United States must withdraw from
INTELSAT, but the President would have discretion to extend this deadline.
 
   The House of Representatives is also expected to consider satellite
legislation this year. Satellite legislation, however, has not yet been
introduced in the House. We cannot predict whether and to what extent
legislation will be introduced or enacted.
 
Appraisal Rights
 
   Section 29-373 of the District of Columbia Business Corporation Act provides
that you may exercise dissenters' rights. The following is a summary of the
principal steps that you must take to perfect your dissenters' rights under
that statute. You should also read Section 29-373 of the District of Columbia
Business Corporation Act, a copy of which is attached as Appendix II to this
proxy statement/prospectus. If you are considering exercising your dissenters'
rights, you should consult an attorney. Your dissenters' rights will be lost if
the procedural requirements under that statute are not fully and precisely
satisfied. To perfect your dissenters' rights, you must satisfy each of the
following conditions:
 
     (1) File Written Objection and Do Not Vote in Favor of the Merger
  Proposal. You must file with COMSAT before the annual meeting a written
  objection to the merger. A vote against the merger will not satisfy the
  requirement that a written objection be made to COMSAT. Your written
  objection should be delivered to COMSAT at 6560 Rock Spring Drive,
  Bethesda, Maryland 20817, Attention: Corporate Secretary.
 
      .  In addition, you must not vote your shares in favor of the merger
         at the annual meeting. This requirement will be satisfied if:
 
                 (a) a proxy is signed and returned with instructions to vote
              against the merger or to abstain from this vote,
 
                 (b) no proxy is returned and no vote is cast at the annual
              meeting in favor of the merger, or
 
                 (c) you revoke a proxy, and thereafter abstain from voting
              with respect to the merger or vote against the merger at the
              annual meeting.
 
      .  A vote in favor of the merger at the annual meeting constitutes a
         waiver of your dissenters' rights. A proxy that is returned
         signed, but on which no voting preference is indicated, will be
         voted in favor of the merger and will constitute a waiver of your
         dissenters' rights.
 
     (2) Filing Written Demand. If you wish to exercise your dissenters'
  rights, you must, within 20 days after the completion of the merger, make a
  written demand to the corporation surviving the merger for payment of the
  fair value of your shares as of the day prior to the date on which the vote
  was taken approving the merger. The demand should be delivered to COMSAT at
  6560 Rock Spring Drive, Bethesda, Maryland 20817, Attention: Corporate
  Secretary. It is recommended, although not required, that your demand be
  sent by registered or certified mail, return receipt requested. A vote
  against the merger will not itself constitute a demand. COMSAT will not
  notify you as to the date on which the 20-day period expires. In exchange
  for your dissenting shares, you will be paid the fair value of your
  dissenting shares determined in accordance with the procedures under
  District of Columbia law. Your demand must state the number and class of
  shares owned by you. If you fail to make the demand within the 20-day
  period, you will be bound by the terms of the merger.
 
                                       42
<PAGE>
 
    .  If you and the corporation surviving the merger agree on the fair
       value of your dissenting shares within 30 days after completion of
       the merger, payment for your dissenting shares will be made by the
       corporation surviving the merger within 90 days after the completion
       of the merger. You must surrender your dissenting shares to receive
       payment. Upon payment of the agreed value, you will cease to have
       any interest in the dissenting shares or in the corporation
       surviving the merger.
 
      (3) If There is no Agreement with the Surviving Corporation on the
   Value, You Must File a Petition in Court. If, within this 30-day period,
   you and the corporation surviving the merger do not agree as to the fair
   value of your dissenting shares, then you may file a petition in any
   District of Columbia court of competent jurisdiction asking for a finding
   and determination of the fair value of your dissenting shares. The
   petition must be filed within 60 days after the expiration of the 30-day
   period. You will be entitled to judgment against the corporation surviving
   the merger for the amount of the fair value of your dissenting shares as
   of the day before the date on which the vote was taken approving the
   merger. Accrued interest at a rate of 5% per annum to the date of the
   judgment will also be paid. You must surrender to the corporation
   surviving the merger your certificates representing your dissenting shares
   to receive payment. Upon payment of the judgment, you will cease to have
   any interest in your dissenting shares or in the corporation surviving the
   merger. District of Columbia law provides that, unless you file a petition
   within the required time limits, you will be bound by the terms of the
   merger.
 
Resale Restrictions
 
   All shares of Lockheed Martin common stock received by you in the merger
will be freely transferable, except that shares of Lockheed Martin common stock
received by persons who are considered to be COMSAT's "affiliates" under the
Securities Act at the time of the annual meeting may be resold by them only in
transactions permitted by the resale provisions of Rule 145 under the
Securities Act or as otherwise permitted under the Securities Act. Persons who
may be considered to be affiliates of COMSAT generally include individuals or
entities that control, are controlled by, or are under common control with,
COMSAT and may include certain officers and directors of COMSAT, as well as
principal shareholders of COMSAT. The merger agreement requires COMSAT to
exercise its reasonable efforts to cause each of its affiliates to execute a
written agreement to the effect that such person will not offer to transfer any
of the shares of Lockheed Martin common stock issued to such person in the
merger unless:
 
      (a) the transfer has been registered under the Securities Act,
 
      (b) the transfer is made in conformity with Rule 145 under the
   Securities Act, or
 
      (c) in the opinion of counsel or pursuant to a "no-action" letter
   obtained from the SEC by such person, the transfer is exempt from
   registration under the Securities Act.
 
COMSAT has agreed to use all reasonable efforts to obtain agreements from its
affiliates not to engage in any of these transactions.
 
                                       43
<PAGE>
 
                              THE MERGER AGREEMENT
 
   We believe this summary describes all material terms of the merger
agreement. However, we recommend that you read the merger agreement. The merger
agreement is included in the document as Appendix I.
 
The Tender Offer
 
   On September 25, 1998, Regulus commenced a tender offer to purchase a non-
controlling interest of up to 49% of the outstanding shares of COMSAT common
stock at a price of $45.50 per share. As soon as legally permissible, Regulus
will pay for all shares of COMSAT common stock validly tendered and not
withdrawn, subject to proration, if applicable. The tender offer is currently
scheduled to expire on July 2, 1999 but will be extended, as necessary, until
September 18, 1999.
 
Conditions to the Tender Offer
 
   Regulus is not required to complete the tender offer unless:
 
  .  any waiting period under the antitrust laws has expired and all required
     consents or approvals under the antitrust laws have been received;
 
  .  at least one-third of the outstanding shares of COMSAT common stock has
     been tendered;
 
  .  the COMSAT shareholders have approved the merger and the merger
     agreement;
 
  .  Lockheed Martin and Regulus have received all necessary approvals from
     the FCC to acquire COMSAT Government Systems;
 
  .  Regulus has received the FCC's approval to become an authorized carrier
     and acquire a non-controlling interest of up to 49% of the shares of
     COMSAT common stock in the tender offer;
 
  .  Lockheed Martin has the right to vote any of the shares of COMSAT common
     stock acquired in the tender offer, subject to the restrictions
     contained in the Satellite Act; and
 
  .  COMSAT has not materially breached the merger agreement in a way that
     would reasonably be expected to materially adversely affect COMSAT.
 
   In addition, Regulus is not required to complete the tender offer if:
 
  .  any circumstance exists that would reasonably be expected to have a
     material adverse effect on COMSAT;
 
  .  there is a general suspension of trading in securities on the New York
     Stock Exchange, other than intraday trading halts;
 
  .  a banking moratorium is declared or any payments in respect of banks in
     the U.S. are suspended;
 
  .  armed hostilities or any other calamity involving the U.S. occurs that
     would reasonably be expected to have a material adverse effect on COMSAT
     or would reasonably be expected to materially adversely affect or
     materially delay the completion of the tender offer, or a material
     acceleration, escalation or worsening of these conditions as they
     existed on September 25, 1998;
 
  .  any limitation is imposed by any U.S. governmental authority that
     materially adversely affects the extension of credit by financial
     institutions generally;
 
  .  the Standard & Poor's 500 Index declines to 744.06 or below through any
     day before the termination or expiration of the tender offer and is at
     or below 744.06 on the earlier of:
 
    (a) the close of trading on the next trading date at least 30 calendar
      days from the day through which the index initially declined to
      744.06, or
 
 
                                       44
<PAGE>
 
    (b) the close of trading on the trading date immediately before the
      date on which the tender offer would otherwise expire;
 
  .  before the purchase of shares in the tender offer, the COMSAT Board of
     Directors:
 
    (a)  recommends an acquisition proposal by a third party that is
         superior to the merger agreement,
 
    (b) withdraws, modifies or materially qualifies in a manner adverse to
      Lockheed Martin its support of the tender offer, the merger or the
      merger agreement,
 
    (c) recommends another offer to you, or
 
    (d) adopts any resolution to effect any of these events that makes it
      inadvisable for Regulus to accept the shares of COMSAT common stock
      for payment; or
 
  .  the merger agreement is terminated.
 
   Subject to compliance with laws, Lockheed Martin may, if it chooses to,
waive any condition in whole or in part at any time.
 
Employee Benefits
 
   In the merger, Lockheed Martin will assume all outstanding options granted
under COMSAT's stock option plans for employees and directors of COMSAT. Each
option outstanding at the date the merger is completed will fully vest and
become an option to acquire, on the same terms and conditions, the number of
shares of Lockheed Martin common stock that the holder of that option would
have been entitled to receive in the merger had the holder exercised that
option in full immediately before the date the merger is completed. Lockheed
Martin has agreed to file a registration statement on Form S-8 to register the
shares of Lockheed Martin common stock issuable upon the exercise of the
outstanding COMSAT options and reserve for issuance sufficient shares of
Lockheed Martin common stock to provide for the exercise of these options.
 
   For at least one year following the date the merger is completed, Lockheed
Martin will provide each COMSAT employee with qualified plan and employee
welfare plan benefits, other than plans provided exclusively to management,
that are comparable in total to the qualified plan and welfare plan benefits
provided to COMSAT employees immediately before the date the merger is
completed. As of that date, Lockheed Martin will assume and will cause the
corporation surviving the merger to assume specified COMSAT benefit plans.
 
Exchange Procedures
 
   Lockheed Martin will appoint an exchange agent reasonably acceptable to
COMSAT before the date the merger is completed. On that date, Lockheed Martin
will deposit with the exchange agent certificates representing shares of
Lockheed Martin common stock that will be issued to you in exchange for your
certificates of COMSAT common stock. After the completion of the merger, the
exchange agent will send you a letter. The letter will contain instructions on
how to surrender your COMSAT stock certificates to the exchange agent and
receive your certificates for Lockheed Martin common stock and, if applicable,
cash for your fractional shares. You should not send in your COMSAT stock
certificates until you receive a letter from the exchange agent.
 
   You will not be entitled to receive any dividends on shares of Lockheed
Martin common stock until you exchange your COMSAT stock certificates for
Lockheed Martin stock certificates. After you deliver your COMSAT stock
certificates to the exchange agent, you will, subject to applicable laws,
receive any accumulated dividends or distribution less the amount of any
withholding taxes, without interest.
 
 
                                       45
<PAGE>
 
Interim Operations
 
   Until the merger is completed, COMSAT has agreed to generally conduct its
business in the ordinary course. COMSAT will use commercially reasonable
efforts to:
 
  .  preserve intact its business organization and goodwill;
 
  .  maintain satisfactory relationships with those persons having business
     relationships with it; and
 
  .  keep available its officers' and employees' services.
 
   Until the merger is completed, subject to specified exceptions which
generally permit COMSAT to conduct its business in the ordinary course, COMSAT
will not take specific actions without Lockheed Martin's consent, including the
following:
 
  .  changing governing documents;
 
  .  issuing securities and paying dividends;
 
  .  pledging or encumbering shares of capital stock;
 
  .  executing or amending employment agreements with directors or executive
     officers;
 
  .  executing or amending employee compensation and benefit plans;
 
  .  disposing of or acquiring material lines of business or assets;
 
  .  making material tax elections and settling tax liabilities;
 
  .  making or committing to make capital expenditures, guarantees and loans;
 
  .  changing accounting methods;
 
  .  paying material liabilities;
 
  .  adopting plans of liquidation, merger, or other material
     reorganizations; and
 
  .  taking any action that would make any representation or warranty of
     COMSAT in the merger agreement untrue as of the date the merger is
     completed.
 
   In addition, other than actions taken by COMSAT as instructed by U.S.
governmental authorities or otherwise taken in good faith, in relation to its
investment in INTELSAT and Inmarsat, COMSAT has agreed not to:
 
  .  dispose of its interests in INTELSAT or Inmarsat;
 
  .  enter into an agreement to vote any of its interests in INTELSAT or
     Inmarsat that would be binding on Lockheed Martin or COMSAT following
     the merger;
 
  .  enter into any lock-up, standstill or other similar agreement with
     respect to its interests in INTELSAT or Inmarsat that would be binding
     on Lockheed Martin or COMSAT following the merger, except in connection
     with an initial public offering by INTELSAT, Inmarsat or New Skies
     Satellites, N.V.; or
 
  .  take, or fail to take, any other action that would reasonably be
     expected to materially impair its interests in INTELSAT or Inmarsat.
 
No Solicitation
 
   COMSAT has agreed to, and has agreed to cause its officers, directors,
employees, consultants and other advisors to:
 
  .  cease discussions or negotiations with any person with respect to any
     acquisition proposal;
 
  .  not solicit or initiate, or knowingly encourage the submission of, any
     acquisition proposal; and
 
  .  not participate in any discussions or negotiations regarding, or give to
     any person other than Lockheed Martin or its representatives or
     affiliates, any information that may reasonably be expected to lead to
     an acquisition proposal.
 
                                       46
<PAGE>
 
   If before the annual meeting, the COMSAT Board of Directors determines in
good faith, that it must do so to comply with its fiduciary duties to you, the
COMSAT Board of Directors may permit COMSAT to respond to an unsolicited
acquisition proposal by furnishing nonpublic information concerning COMSAT and
by participating in discussions or negotiations regarding that acquisition
proposal.
 
   The term "acquisition proposal" means any proposal or offer from any third
party:
 
  .  to acquire assets of COMSAT with a value equal to more than 10% of
     COMSAT's market capitalization;
 
  .  for a tender offer or exchange offer that, if completed, would result in
     any person beneficially owning more than 10% of COMSAT's common stock;
     or
 
  .  for a merger, consolidation, business combination, sale of all or
     substantially all the assets, recapitalization, liquidation, dissolution
     or similar transaction involving COMSAT.
 
   COMSAT has agreed that the COMSAT Board of Directors will not:
 
  .  withdraw, modify or qualify, in a manner adverse to Lockheed Martin, its
     support of the tender offer, the merger or the merger agreement;
 
  .  approve or recommend any acquisition proposal;
 
  .  enter into any agreement with respect to any acquisition proposal; or
 
  .  publicly propose to take any of the above actions.
 
   However, if before the annual meeting, the COMSAT Board of Directors
determines in good faith, that it must do so to comply with its fiduciary
duties to you, the COMSAT Board of Directors may terminate the merger agreement
to concurrently enter into a definitive agreement to effect a superior
proposal.
 
   A "superior proposal" must be a proposal or offer from a third party to
acquire more than 50% of the then outstanding shares of COMSAT common stock or
all the assets of COMSAT. When considering this proposal, the COMSAT Board of
Directors must determine, based on the advice of a financial advisor, that the
superior proposal is more favorable to you than the tender offer and the merger
and has committed financing, to the extent required, or is reasonably capable
of being financed by that person.
 
   COMSAT must advise Lockheed Martin if COMSAT receives any acquisition
proposal, a request for information or an inquiry that could lead to or is
related to any acquisition proposal, the identity of the person making the
request or acquisition proposal and the material terms of any acquisition
proposal. COMSAT must keep Lockheed Martin fully informed of the status and
terms of any request or acquisition proposal unless the COMSAT Board of
Directors determines in good faith that it should not do so to comply with its
fiduciary duties to you.
 
Reasonable Efforts to Complete the Tender Offer and the Merger
 
   Lockheed Martin and COMSAT have agreed to use all reasonable efforts to
complete the tender offer and the merger. This obligation includes cooperating
and using reasonable efforts to promptly make all filings and obtain all
consents and approvals of governmental authorities and other persons necessary
to complete the transactions and to resolve any objections that may be asserted
under any antitrust law or any other applicable law.
 
                                       47
<PAGE>
 
   If any person initiates, or threatens to initiate, a proceeding or other
action challenging any transaction contemplated by the merger agreement as
violative of any law, Lockheed Martin and COMSAT will cooperate to contest the
proceeding, and to have reversed any decision or other official action of any
governmental authority that restricts completion of any transaction
contemplated by the merger agreement, including pursuing all reasonable avenues
of appeal. But:
 
  .  in no event is Lockheed Martin required to agree to hold separate or to
     divest any of its businesses or assets, or agree to any other
     restriction or condition with respect to the acquisition, ownership,
     conduct or operation of any of its businesses or assets, or following
     the completion of the tender offer or the merger, of COMSAT; and
 
  .  except for seeking review by the full FCC of any staff decision denying
     an application to permit the transfer of control of COMSAT Government
     Systems to Regulus, to cause Regulus to become an authorized carrier or
     to complete the tender offer, Lockheed Martin is not required to contest
     an action or pending legal proceeding or take any other action if, after
     taking into account advice of independent counsel, the Lockheed Martin
     Board of Directors determines in good faith that any contest or other
     action is not in the best interests of Lockheed Martin.
 
Directors' and Officers' Insurance; Indemnification
 
   Lockheed Martin has agreed to cause the corporation surviving the merger to
indemnify the present and former officers, directors, employees and agents of
COMSAT against all losses related to actions or omissions or alleged actions or
omissions occurring at or before the date the merger is completed on the same
terms as COMSAT's articles of incorporation and bylaws and agreements in effect
on September 18, 1998 subject to applicable law on the date the merger is
completed.
 
   For a six-year period after the merger, Lockheed Martin will use reasonable
efforts to maintain the current policies of directors' and officers' liability
insurance maintained by COMSAT with respect to claims arising from or events
that occurred at or before the date the merger is completed. Lockheed Martin
will not be obligated to make annual premium payments for any insurance to the
extent the premiums exceed 150% of the annual premiums paid by COMSAT for this
insurance as of September 18, 1998. Lockheed Martin may substitute policies
with at least the same coverage and amounts containing terms and conditions
that are no less advantageous in the aggregate.
 
Conditions to the Merger
 
   COMSAT and Lockheed Martin are not obligated to complete the merger unless:
 
  .  the tender offer has been completed;
 
  .  the Satellite Act and other applicable laws have been amended, and all
     applicable proceedings before all governmental authorities have been
     completed, to permit the merger;
 
  .  any waiting period under antitrust laws has terminated or expired, and
     all consents or approvals required under antitrust laws have been
     received;
 
  .  the shares of Lockheed Martin common stock to be issued in the merger
     have been approved for listing on the New York Stock Exchange;
 
  .  the registration statement relating to this proxy statement/prospectus
     has been declared effective by the SEC, no stop order suspending its
     effectiveness has been issued and no proceedings for that purpose have
     been initiated or threatened; and
 
  .  the merger and the merger agreement have been approved by you.
 
   In addition, Lockheed Martin is not obligated to complete the merger if:
 
  .  all consents and approvals required for the completion of the merger
     have not been granted, except where the failure to obtain these consents
     or approvals would not reasonably be expected to have a significant
     adverse effect on COMSAT; and
 
                                       48
<PAGE>
 
  .  there occurs any event that has had or would reasonably be expected to
     have a significant adverse effect on COMSAT.
 
   COMSAT and Lockheed Martin will not be required to complete the merger as a
forward merger, unless the following conditions are satisfied. If the following
conditions are not satisfied, but the conditions set forth in the above
paragraphs are satisfied, the merger will be completed as a reverse merger, and
as a result the merger will be taxable to you:
 
  .  the value of the shares of Lockheed Martin common stock deliverable in
     the merger must constitute no less than 40% of the consideration
     received by COMSAT shareholders in the tender offer and the merger;
 
  .  COMSAT and Lockheed Martin must receive tax opinions from their
     respective counsel to the effect that the forward merger will constitute
     a "reorganization" within the meaning of Section 368(a) of the Internal
     Revenue Code; and
 
  .  COMSAT and Lockheed Martin must receive all required consents or
     approvals necessary to permit the completion of the forward merger,
     except where the failure to obtain these consents or approvals would not
     reasonably be expected to have a material adverse effect on COMSAT.
 
   A "material adverse effect" is any change or effect that is materially
adverse to:
 
  .  the business, properties, operations, results of operations or financial
     condition of COMSAT other than any effects or changes arising out of,
     resulting from or relating to general economic, financial or industry
     conditions; or
 
  .  the ability of COMSAT to perform its obligations under the merger
     agreement and the carrier acquisition agreement.
 
   A "significant adverse effect" is a material adverse effect on COMSAT of
such seriousness and significance that a reasonable businessperson in similar
circumstances would not proceed with the merger on the terms and conditions set
forth in the merger agreement. In determining whether a change or event has a
material adverse effect that would constitute a significant adverse effect,
effects or changes relating to general economic, financial or industry
conditions are considered.
 
Representations and Warranties
 
   COMSAT has made customary representations and warranties to Lockheed Martin
about its organization, capitalization, financial statements, public filings,
conduct of business, compliance with laws, litigation, noncontravention,
consents and approvals, opinions of financial advisors, undisclosed liabilities
and the absence of certain changes with respect to COMSAT since June 30, 1998.
 
   Lockheed Martin has made customary representations and warranties to COMSAT
about its organization, capitalization, financial statements, public filings,
noncontravention, consents and approvals, opinion of financial advisors and the
absence of certain changes with respect to Lockheed Martin since June 30, 1998.
 
Termination; Termination Fees
 
 Termination by Either COMSAT or Lockheed Martin.
 
   COMSAT and Lockheed Martin may terminate the merger agreement and abandon
the tender offer and the merger by mutual written consent. Either party may
also terminate the merger agreement if:
 
     (1) any U.S. court or other U.S. governmental authority permanently
  prohibits the completion of the tender offer or the merger;
 
     (2) COMSAT shareholders do not approve the merger by September 18, 1999;
  or
 
     (3) the merger has not occurred by September 18, 2000, so long as the
  party seeking to terminate has not materially breached the merger
  agreement.
 
 
                                       49
<PAGE>
 
 Termination by COMSAT.
 
   COMSAT may also terminate the merger agreement if:
 
     (1) COMSAT has not materially breached the merger agreement, and
  Lockheed Martin:
 
           .  terminates the tender offer without purchasing COMSAT common
              stock; or
 
           .  fails to acquire COMSAT common stock in the tender offer by
              September 18, 1999;
 
     (2) before Lockheed Martin acquires COMSAT common stock in the tender
  offer, the COMSAT Board of Directors determines to accept an acquisition
  proposal that is a superior proposal and approves an agreement relating to
  it, or adopts such a resolution; however, the merger agreement will not
  terminate until COMSAT pays the required termination fee; or
 
     (3) before Lockheed Martin acquires COMSAT common stock in the tender
  offer, Lockheed Martin breaches the merger agreement in a way that would
  reasonably be expected to materially adversely affect, or materially delay,
  the completion of the tender offer.
 
 Termination by Lockheed Martin.
 
   Lockheed Martin may also terminate the merger agreement if:
 
     (1) Lockheed Martin has not materially breached the merger agreement
  and, because a condition to Lockheed Martin's obligation to acquire COMSAT
  common stock in the tender offer has not been satisfied or waived, Lockheed
  Martin:
 
           .  terminates the tender offer without purchasing COMSAT common
              stock; or
 
           .  fails to accept COMSAT common stock in the tender offer by
              September 18, 1999;
 
     (2) before Lockheed Martin acquires COMSAT common stock in the tender
  offer:
 
           .  COMSAT breaches the merger agreement in a way that would
              reasonably be expected to materially adversely affect, or
              materially delay, the completion of the tender offer.
 
           .  the COMSAT Board of Directors:
 
                 (a) determines that an acquisition proposal is a superior
              proposal,
 
                 (b) withdraws, modifies or materially qualifies in a manner
              adverse to Lockheed      Martin its support for the tender
              offer, the merger or the merger agreement,
 
                 (c) recommends another acquisition proposal to COMSAT
              shareholders, or
 
                 (d) adopts a resolution to effect any of the above; or
 
           .  at least one-third of the COMSAT common stock is not tendered by
              the expiration of the tender offer and someone other than
              Lockheed Martin commences, publicly proposes or publicly
              discloses an acquisition proposal.
 
 Termination Fees.
 
   COMSAT must pay Lockheed Martin a $75 million termination fee if the merger
agreement is terminated by either COMSAT or Lockheed Martin because:
 
     (1) at least one-third of the COMSAT common stock is not tendered by the
  expiration of the tender offer and someone other than Lockheed Martin
  commences, publicly proposes or publicly discloses an acquisition proposal;
  or
 
 
                                       50
<PAGE>
 
     (2) COMSAT shareholders do not approve the merger by September 18, 1999;
  and, within 12 months after that date:
 
           .  COMSAT enters into an agreement with respect to or completes
              another acquisition proposal with a third party:
 
                 (a) with whom COMSAT discussed an acquisition proposal after
              September 18, 1998 and before termination of the merger
              agreement,
 
                 (b) to whom COMSAT furnished information with respect to an
              acquisition proposal after September 18, 1998 and before
              termination of the merger agreement, or
 
                 (c) who had commenced, publicly proposed or publicly
              disclosed an acquisition proposal, or expressed to COMSAT
              interest in an acquisition proposal, after September 18, 1998
              and before termination of the merger agreement.
 
   If COMSAT decides to accept an acquisition proposal that is a superior
proposal and approves an agreement relating to it, or adopts such a resolution,
and terminates the merger agreement before Lockheed Martin acquires COMSAT
common stock in the tender offer, COMSAT must also pay Lockheed Martin the $75
million termination fee.
 
Fees and Expenses
 
   Except as specifically provided in the merger agreement or the registration
rights agreement, each party will pay its own expenses in connection with the
merger agreement and related transactions. However, if the termination fee is
payable, COMSAT agrees to promptly reimburse Lockheed Martin for up to $5
million of its expenses.
 
Other Transaction Documents
 
   The following are summaries of several agreements executed in connection
with the merger agreement. We believe these summaries describe all material
terms of each of these agreements. However, we recommend that you read each
agreement. These agreements are incorporated in this proxy statement/prospectus
by reference from the exhibits to COMSAT's Schedule 14D-9 filed with the SEC on
September 25, 1998.
 
 Confidentiality Agreements.
 
   COMSAT and Lockheed Martin executed separate confidentiality agreements,
each dated as of August 5, 1997. The confidentiality agreements contain
customary provisions under which Lockheed Martin and COMSAT agreed to keep
confidential all nonpublic, confidential or proprietary information furnished
to one party by the other, subject to exceptions, and to use confidential
information solely for the purpose of evaluating a possible transaction
involving COMSAT and Lockheed Martin. Lockheed Martin and COMSAT also agreed
that, unless otherwise agreed in writing, neither would for a three-year period
from the agreements' date, acquire or offer to acquire or agree to acquire any
securities or assets of the other party. Lockheed Martin and COMSAT further
agreed that, for a two-year period from the date of the confidentiality
agreements, without the prior written consent of the other party, neither would
solicit for employment any of the current employees of the other party.
 
                                       51
<PAGE>
 
 Shareholders Agreement.
 
   In connection with the execution of the merger agreement, COMSAT and
Lockheed Martin have executed a shareholders agreement dated as of September
18, 1998 under which promptly, but no more than 30 days after the completion of
the tender offer, until the completion of the merger or until the shareholders
agreement is otherwise terminated, COMSAT agreed to take all actions necessary
to cause:
 
     (a) three individuals selected by Lockheed Martin to become members of
  the COMSAT Board of Directors;
 
     (b) the appointment of one of the three individuals selected by Lockheed
  Martin to become members of the COMSAT Board of Directors as a member of
  each committee of the COMSAT Board of Directors; and
 
     (c) if any Lockheed Martin designee ceases to be a director, the filling
  of the vacancy with an individual selected by Lockheed Martin.
 
   Any Lockheed Martin officer or employee serving as a COMSAT director will be
considered a Lockheed Martin designee.
 
   COMSAT further agreed not to amend or repeal the provisions of the COMSAT
bylaws which permit any three directors to call a special meeting of the COMSAT
Board of Directors or to otherwise amend the COMSAT articles of incorporation
or bylaws in any manner that would adversely affect the rights of Lockheed
Martin under either the shareholders agreement or the registration rights
agreement discussed below.
 
   COMSAT also agreed, at Lockheed Martin's request, to cause COMSAT's
directors to adopt resolutions to approve, recommend and submit for shareholder
approval, an amendment to the COMSAT articles of incorporation to eliminate
certain restrictions relating to the transfer of securities.
 
   In addition, Lockheed Martin agreed not to:
 
     (a) purchase more than 49% of the outstanding shares of COMSAT common
  stock, unless approved by COMSAT;
 
     (b) transfer its COMSAT shares, except in compliance with applicable law
  and upon receipt of any necessary approvals of any governmental authority;
 
     (c) transfer any shares of COMSAT common stock except through a
  registered public offering or through an open market "brokers" transaction;
  and
 
     (d) solicit proxies in opposition to any matter that has been
  recommended by the COMSAT Board of Directors or in favor of any matter that
  has not been approved by the COMSAT Board of Directors.
 
 Registration Rights Agreement.
 
   Demand Registration Rights. Lockheed Martin and COMSAT have entered into a
registration rights agreement under which, after the termination of the merger
agreement and assuming the completion of the tender offer, Lockheed Martin has
the right to require COMSAT to prepare and file up to five registration
statements under the Securities Act to register shares of COMSAT common stock
held by Lockheed Martin. However, COMSAT is not required to register less than
3,000,000 shares of COMSAT common stock in the aggregate. In addition if, with
respect to an underwritten offering, the managing underwriter advises against
proceeding with an offering because the number of shares of COMSAT common stock
proposed to be included in an offering would adversely affect the offering,
Lockheed Martin can request registration of the maximum number of shares of
COMSAT common stock that it is advised can be sold without adverse effect, so
long as the request relates to 3,000,000 shares or more. Alternatively,
Lockheed Martin may elect not to proceed. If it does so, this will not count as
use of one of the demands. Expenses related to the exercise of this right will
generally be payable by COMSAT.
 
 
                                       52
<PAGE>
 
   Piggy-Back Registration Rights. Under the registration rights agreement,
Lockheed Martin also has the right, with respect to any underwritten offerings,
including registered offerings, of COMSAT common stock for cash proposed by
COMSAT, to require COMSAT to include COMSAT common stock held by Lockheed
Martin in an offering and registration, except COMSAT will not be required to
register COMSAT common stock owned by Lockheed Martin in any registration
statement relating to acquisitions or employee benefit plans or filed in
connection with an exchange offer or other offering of securities solely to the
then-existing COMSAT shareholders. Expenses relating to exercises of this right
will generally be payable by COMSAT.
 
   In other respects, the registration rights agreement contains terms that are
customary to registration rights agreements of its type including mutual
indemnification provisions and black-out provisions relating to the prohibition
of the sale of shares of COMSAT common stock for a specified period of time.
 
 Carrier Acquisition Agreement.
 
   To facilitate the completion of the tender offer and the merger, Lockheed
Martin and COMSAT entered into a carrier acquisition agreement with Regulus and
COMSAT Government Systems, under which COMSAT Government Systems will be merged
with Regulus as soon as practicable following the satisfaction or waiver of the
conditions set forth in the agreement, or on another date agreed upon by the
parties, before the completion of the tender offer. At the date the merger of
Regulus and COMSAT Government Systems is completed, Regulus will acquire the
common carrier telecommunications business of COMSAT Government Systems and
COMSAT Government Systems' FCC common carrier authorization.
 
                                       53
<PAGE>
 
                                 THE COMPANIES
 
Lockheed Martin
 
   Lockheed Martin was formed in March 1995 by the combination of the
businesses of Martin Marietta Corporation and Lockheed Corporation. Lockheed
Martin's principal executive offices are located at 6801 Rockledge Drive,
Bethesda, Maryland 20817, and its telephone number is (301) 897-6000.
 
   Lockheed Martin is a highly diversified global enterprise principally
engaged in the conception, research, design, development, manufacture,
integration and operation of advanced technology products and services.
Lockheed Martin operates through five business sectors:
 
  .  Space & Strategic Missiles sector--designs, develops, manufactures and
     integrates space systems, including spacecraft, space launch vehicles,
     manned space systems and their supporting ground systems and services,
     strategic fleet ballistic missiles and defensive missiles;
 
  .  Electronics sector--designs, develops, manufactures and integrates high
     performance electronic systems for undersea, shipboard, land, airborne
     and space-based applications;
 
  .  Aeronautics sector--designs, develops, manufactures and integrates
     airlift, tactical and reconnaissance aircraft as well as
     surveillance/command, maintenance/modification/logistics and other
     development programs;
 
  .  Information & Services sector--designs, develops, integrates and
     operates large, complex information systems which include command and
     control, intelligence, simulation and training and air traffic
     management; and provides state and local government transaction
     processing, commercial information technology services and performs a
     broad range of engineering, science and technology services for federal
     government customers; and
 
  .  Energy & Environment sector--conducts and operates nuclear operations
     management, nuclear materials management and technology-driven
     remediation programs.
 
   It is expected that the combined businesses and operations of COMSAT and
Lockheed Martin Global Telecommunications will be a sixth sector.
 
Deneb Corporation, Lockheed Martin's merger subsidiary
 
   Deneb is a direct, wholly-owned subsidiary of Lockheed Martin which was
incorporated in Delaware for the sole purpose of effecting the merger. It
engages in no other business. Its principal executive offices are at 6801
Rockledge Drive, Bethesda, Maryland 20817, and its telephone number is (301)
897-6000.
 
COMSAT
 
   COMSAT is a District of Columbia corporation incorporated in 1963. Its
principal executive offices are located at 6560 Rock Spring Drive, Bethesda,
Maryland 20817, and its telephone number is (301) 214-3000.
 
   COMSAT reports operating results and financial data in four business
segments:
 
  .  COMSAT World Systems--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 INTELSAT
     and New Skies Satellites, N.V. The COMSAT World Systems segment also
     includes COMSAT General Corporation, COMSAT Digital Teleport, Inc. and
     COMSAT Government Systems, which provide various satellite and ground
     segment services to commercial and government customers.
 
 
                                       54
<PAGE>
 
  .  COMSAT Mobile Communications--provides satellite telecommunications
     services for maritime, aeronautical and land mobile applications
     primarily using the satellite system of Inmarsat.
 
  .  COMSAT International--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.
 
  .  COMSAT Laboratories--provides technical consulting services and develops
     advanced communications technologies and products for satellite access
     and networking applications.
 
                                       55
<PAGE>
 
                                  MARKET DATA
 
   Lockheed Martin common stock is listed on the New York Stock Exchange under
the symbol "LMT." COMSAT common stock is listed on the New York Stock Exchange
under the symbol "CQ" and on the Chicago and Pacific Stock Exchanges in the
U.S. and on the Swiss Exchange in Switzerland. On December 31, 1998, Lockheed
Martin effected a two-for-one stock split of its common stock in the form of a
stock dividend, and the information presented below for Lockheed Martin has
been adjusted to reflect this stock split. The table below sets forth, for the
calendar quarters indicated, the high and low sales prices per share reported
on the New York Stock Exchange Composite Tape, and the dividends declared on
Lockheed Martin common stock and on COMSAT common stock, respectively.
 
<TABLE>
<CAPTION>
                             Lockheed Martin                     COMSAT
                              Common Stock                    Common Stock
                         ------------------------------- -------------------------------
                          High       Low       Dividends  High      Low        Dividends
                         ------     ------     --------- ------    ------      ---------
<S>                      <C>        <C>        <C>       <C>       <C>         <C>
1996:
First Quarter........... $  40 7/16 $  36 9/16   $0.20   $  25 5/8 $  16 3/4     $.195
Second Quarter..........    43 3/8     36 1/2     0.20      33 1/8    23 3/8      .195
Third Quarter...........    45 7/8     38 1/8     0.20      26 1/2    18 3/4      .195
Fourth Quarter..........    48 5/16    42 5/8     0.20      26 3/4    21 1/2      .195
1997:
First Quarter........... $  46 7/16    $41       $0.20   $  28 1/2 $   23        $.195
                                                             26
Second Quarter..........    52 5/8     39 1/8     0.20    11/16       19 5/8       .05
                             56         49                   24        20
Third Quarter...........  23/32       3/16        0.20     5/16     13/16          .05
                             54         44                             20
Fourth Quarter..........   7/32       1/16        0.20      25 3/4   5/16          .05
1998:
                         $   58
First Quarter...........  15/16     $  48 3/4    $0.20   $   36    $  21 5/8     $ .05
                                        49
Second Quarter..........    58 1/2   31/32        0.20      42 3/4    27 3/4       .05
Third Quarter...........    54 1/4     43 5/8     0.20      36 7/8    21 13/16     .05
                                                                       32
Fourth Quarter..........    56 3/4      41        0.22      39 5/8   7/16          .05
1999:
                                                         $   36
First Quarter........... $   42     $  35 1/4    $0.22    11/16       $27        $ .05
Second Quarter
(through May 7, 1999)...    44 9/16    36 5/16    0.22      35 1/8    27 13/16     .05
</TABLE>
 
   The last reported closing sales prices per share on the New York Stock
Exchange Composite Tape of Lockheed Martin common stock and COMSAT common stock
on September 18, 1998, the last trading day before public announcement of the
merger, were $50 and $34 1/8, respectively. On May 7, 1999, the last day for
which it was practicable to obtain this information prior to the mailing of
this proxy statement/prospectus, the closing sales price per share on the New
York Stock Exchange Composite Tape of Lockheed Martin common stock and the
COMSAT common stock was $33 and $43 7/16, respectively.
 
  Because the exchange ratio in the merger is fixed and because the market
price of Lockheed Martin common stock is subject to fluctuation, the market
value of the shares of Lockheed Martin common stock that you will receive in
the merger will increase or decrease prior to and following the merger. You are
urged to obtain current market quotations for Lockheed Martin common stock and
COMSAT common stock. See "Risk Factors--Value of Lockheed Martin Common Stock
You will Receive in the Merger will Fluctuate."
 
 
                                       56
<PAGE>
 
                LOCKHEED MARTIN SELECTED HISTORICAL CONSOLIDATED
                             FINANCIAL INFORMATION
 
   The selected historical financial information of Lockheed Martin for the
years 1998, 1997 and 1996 presented below, with the exception of the balance
sheet data for 1996, has been derived from the audited consolidated financial
statements of Lockheed Martin incorporated by reference in this proxy
statement/prospectus. The balance sheet data for 1996 and the financial
information for 1995 and 1994 has been derived from audited consolidated
financial statements previously filed with the SEC but not incorporated by
reference in this proxy statement/prospectus. Lockheed Martin was formed in
1995 from the combination of Lockheed Corporation and Martin Marietta
Corporation. Financial information for 1994 was derived from the financial
statements of those companies under the pooling of interests method of
accounting. The information shown below should be read in conjunction with the
historical consolidated financial statements of Lockheed Martin, including the
related notes thereto. See "Where You Can Find More Information" on page 105.
 
<TABLE>
<CAPTION>
                                                      At or For
                                               Year Ended December 31,
                                       ----------------------------------------
                                       1998(2) 1997(3)  1996(4) 1995(5) 1994(6)
                                       ------- -------  ------- ------- -------
                                        (In millions, except per share data)
<S>                                    <C>     <C>      <C>     <C>     <C>
Income Statement Data:
  Net sales........................... $26,266 $28,069  $26,875 $22,853 $22,906
  Earnings before cumulative effect of
   change in accounting...............   1,001   1,300    1,347     682   1,055
  Net earnings........................   1,001   1,300    1,347     682   1,018
  Net earnings (loss) per common
   share:(1)
    Basic:
      Before cumulative effect of
       change in accounting...........    2.66   (1.56)    3.40    1.64    2.66
      Net earnings (loss).............    2.66   (1.56)    3.40    1.64    2.56
    Diluted:
      Before cumulative effect of
       change in accounting...........    2.63   (1.56)    3.04    1.54    2.43
      Net earnings (loss).............    2.63   (1.56)    3.04    1.54    2.34
  Cash dividends per common share(1)..     .82     .80      .80     .67     .57
Balance Sheet Data:
  Total assets........................ $28,744 $28,361  $29,540 $17,558 $17,979
  Short-term borrowings...............   1,043     494    1,110     --      --
  Current maturities of long-term
   debt...............................     886     876      180     722     285
  Long-term debt......................   8,957  10,528   10,188   3,010   3,594
  Stockholders' equity................   6,137   5,176    6,856   6,433   6,086
</TABLE>
- --------
 
(1) All share and per share amounts have been restated to reflect a two-for-one
    stock split in the form of a stock dividend in December 1998.
 
(2) Includes the effects of a nonrecurring and unusual pretax charge of $233
    million, $183 million after tax, or $.48 per diluted share.
 
(3) Includes the effects of a tax-free gain of $311 million and the effects of
    nonrecurring and unusual pretax charges of $457 million, $303 million after
    tax which, on a combined basis, decreased diluted loss per share by $.02.
    Loss per share also includes the effects of a deemed dividend resulting
    from a transaction with the holder of Lockheed Martin's series A preferred
    stock which reduced the basic and diluted per share amounts by $4.93.
 
(4) Reflects a business combination with Loral Corporation effective April
    1996. Includes the effects of a nonrecurring pretax gain of $365 million,
    $351 million after tax, and nonrecurring pretax charges of $307 million,
    $209 million after tax which, on a combined basis, increased diluted
    earnings per share by $.32.
 
(5) Includes the effects of merger related and consolidation expenses totaling
    $690 million, $436 million after tax, or $.99 per diluted share.
 
(6) Includes a cumulative effect adjustment related to Lockheed Martin's change
    in the method of accounting for its leveraged employee stock ownership
    plan.
 
 
                                       57
<PAGE>
 
         COMSAT SELECTED HISTORICAL CONSOLIDATED FINANCIAL INFORMATION
 
   COMSAT is providing the following consolidated financial information to aid
you in analyzing the financial aspects of the merger. This information is
derived from COMSAT's audited consolidated financial statements for 1994
through 1998. The information is only a summary, and you should read it in
conjunction with COMSAT's historical consolidated financial statements and
related notes contained in its annual reports and other information filed with
the SEC. See "Where You Can Find More Information" on page 105.
 
<TABLE>
<CAPTION>
                                                       At or For
                                                Year Ended December 31,
                                        -----------------------------------------
                                         1998   1997(1)    1996    1995    1994
                                        ------- --------- ------- ------- -------
                                          (In millions, except per share data)
<S>                                     <C>     <C>       <C>     <C>     <C>
Summary of Operations:
 Revenues.............................  $   616 $   563   $   545 $   508 $   500
 Operating expenses...................      557     481       438     388     367
 Operating income.....................       59      82       107     120     133
 Income from continuing operations....       26      29        36      44      69
 Net income (loss)....................       26     (64)        9      38      78
 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 (at end of period):
 Total assets.........................    1,791   1,895     2,097   2,022   1,851
 Long-term debt.......................      447     462       578     590     511
 Stockholders' equity.................      659     586       842     839     827
Dividends:
 Dividends paid.......................       10      17        38      37      34
 Dividends paid per share.............     0.20   0.345      0.78    0.78    0.76
 Distribution of Ascent Entertainment
  Group, Inc. shares..................      --      195       --      --      --
</TABLE>
- --------
(1) COMSAT began accounting for Ascent Entertainment Group, Inc. and
    substantially all of COMSAT RSI, Inc. as discontinued operations in 1997.
    Accordingly, all prior periods were restated to present Ascent and COMSAT
    RSI as discontinued operations.
 
                                       58
<PAGE>
 
          UNAUDITED PRO FORMA COMBINED CONDENSED FINANCIAL INFORMATION
 
   The following unaudited pro forma combined condensed financial statements
are based upon Lockheed Martin's and COMSAT's historical consolidated financial
statements incorporated by reference in this proxy statement/prospectus, and
have been prepared to reflect the tender offer and proposed merger based on the
purchase method of accounting. The unaudited pro forma combined condensed
statement of earnings, which has been prepared for the year ended December 31,
1998, gives effect to the tender offer and the merger as if they had occurred
at January 1, 1998. The unaudited pro forma combined condensed balance sheet
has been prepared as of December 31, 1998, and gives effect to the tender offer
and the merger as if they had occurred on that date. Lockheed Martin prepared
the unaudited pro forma adjustments based upon financial data provided by
COMSAT, and upon preliminary estimates and assumptions that management of
Lockheed Martin believes are reasonable under the circumstances. These pro
forma financial statements have been reviewed by management of COMSAT. While no
material adjustments are expected to occur to the pro forma financial
statements based upon information currently available, events may occur between
now and completion of the merger, including among others, developments
concerning the privatization of INTELSAT, amendment of the Satellite Act and
other items discussed under the caption "Risk Factors," which could materially
affect the pro forma adjustments.
 
   The unaudited pro forma combined condensed financial statements are not
necessarily indicative of actual or future financial position or results of
operations that would have occurred or will occur upon completion of the tender
offer and the merger. Lockheed Martin expects to ultimately dispose of its
equity interests in various investment holdings to fund the tender offer. These
statements, however, assume the issuance of debt obligations as the funding
source because Lockheed Martin presently anticipates that market conditions and
contractual limitations on its ability to dispose of the investments make
disposition before the tender offer is completed unlikely. In addition, these
statements do not include the effects of any estimated transition or
restructuring costs which may be incurred in connection with integrating the
operations of COMSAT into Lockheed Martin. It is not feasible at this time to
estimate the effect of such funding strategies or costs for pro forma purposes.
Additionally, the unaudited pro forma combined condensed statement of earnings
does not reflect any net cost savings or economies of scale that may have
occurred had the merger been completed at the beginning of the period.
 
   The unaudited pro forma combined condensed financial statements are based
upon, and should be read in conjunction with, the historical consolidated
financial statements of Lockheed Martin and COMSAT, including the respective
related notes, which are incorporated by reference in this proxy
statement/prospectus. See "Where You Can Find More Information" on page 105.
 
          Unaudited Pro Forma Combined Condensed Statement of Earnings
 
<TABLE>
<CAPTION>
                                     For The Year Ended December 31, 1998
                         -----------------------------------------------------------------
                         Historical
                          Lockheed  Historical                    Pro Forma      Pro Forma
                           Martin     COMSAT   Reclassifications Adjustments     Combined
                         ---------- ---------- ----------------- -----------     ---------
                                     (In millions, except per share data)
<S>                      <C>        <C>        <C>               <C>             <C>
Net sales...............  $26,266      $616          $(59)          $  (1)(A)     $26,822
Cost of sales...........   23,914       557             7              51 (A)(B)   24,529
                          -------      ----          ----           -----         -------
Earnings from
 operations.............    2,352        59           (66)            (52)          2,293
Other income and
 expenses, net..........      170        13            51             (32)(C)         202
                          -------      ----          ----           -----         -------
                            2,522        72           (15)            (84)          2,495
Interest expense........      861        40           (15)             71 (D)         957
                          -------      ----          ----           -----         -------
Earnings before income
 taxes..................    1,661        32           --             (155)          1,538
Taxes on income.........      660         6           --              (37)(E)         629
                          -------      ----          ----           -----         -------
Net earnings............  $ 1,001      $ 26          $ --           $(118)        $   909
                          =======      ====          ====           =====         =======
Earnings per common
 share:
 Basic:
   Weighted average
    shares..............    376.5                                                   403.4
   Earnings per share...    $2.66                                                   $2.25
 Diluted:
   Weighted average
    shares..............    381.1                                                   410.4
   Earnings per share...    $2.63                                                   $2.21
</TABLE>
 
   See accompanying Notes to Unaudited Pro Forma Combined Condensed Financial
                                  Statements.
 
                                       59
<PAGE>
 
              Unaudited Pro Forma Combined Condensed Balance Sheet
 
<TABLE>
<CAPTION>
                                            As of December 31, 1998
                         ------------------------------------------------------------------
                         Historical
                          Lockheed  Historical                    Pro Forma       Pro Forma
                           Martin     COMSAT   Reclassifications Adjustments      Combined
                         ---------- ---------- ----------------- -----------      ---------
                                                 (In millions)
<S>                      <C>        <C>        <C>               <C>              <C>
Assets
Current assets:
 Cash and cash
  equivalents...........  $   285     $   31         $ --          $  --           $   316
 Receivables............    4,178        131           --             --             4,309
 Inventories............    4,293        --            --             --             4,293
 Deferred income
  taxes.................    1,109          8            (1)             9 (G)        1,125
 Net assets of
  discontinued
  operations............      --          13           (13)           --               --
 Other current assets...      746         16            14              2 (G)          778
                          -------     ------         -----         ------          -------
   Total current
    assets..............   10,611        199           --              11           10,821
Property, plant and
 equipment..............    3,513      1,210          (847)           --             3,876
Intangible assets
 related to contracts
 and programs acquired..    1,418        --            --             --             1,418
Cost in excess of net
 assets acquired........    9,521        --            --           1,317 (G)       10,838
Investments in
 affiliates.............      948        249           591            980 (G)        2,768
Other assets............    2,733        133           (10)            41 (G)        2,897
                          -------     ------         -----         ------          -------
                          $28,744     $1,791         $(266)        $2,349          $32,618
                          =======     ======         =====         ======          =======
Liabilities and
 Stockholders' Equity
Current liabilities:
 Accounts payable.......  $ 1,382     $   88         $  (8)        $  --           $ 1,462
 Customer advances and
  amounts
  in excess of costs
  incurred..............    4,012        --            --             --             4,012
 Salaries, benefits and
  payroll taxes.........      842        --            --             --               842
 Income taxes...........      553        --              1            --               554
 Short-term
  borrowings............    1,043        --            --             170 (F)        1,213
 Current maturities of
  long-term debt........      886         15           (15)           --               886
 Due to related
  parties...............      --          31           (31)           --               --
 Other current
  liabilities...........    1,549          7            59             65 (G)(H)     1,680
                          -------     ------         -----         ------          -------
   Total current
    liabilities.........   10,267        141             6            235           10,649
Long-term debt..........    8,957        447          (238)         1,021 (F)(G)    10,187
Deferred income taxes...      --         127          (127)           --               --
Deferred investment tax
 credits................      --           6           --              (6)(G)          --
Post-retirement benefit
 liabilities............    1,903         49           --             (17)(G)        1,935
Other liabilities.......    1,480        162           293            456 (G)(H)     2,391
Preferred securities
 issued by a
 subsidiary.............      --         200          (200)           --               --
Stockholders' equity:
 Common stock...........      393        431           --            (404)(H)          420
 Additional paid-in
  capital...............       70        --            --           1,292 (H)        1,362
 Retained earnings......    5,864        243           --            (243)(H)        5,864
 Treasury stock, at
  cost, 80 shares.......      --          (3)          --               3 (H)          --
 Unearned ESOP shares...     (182)       --            --             --              (182)
 Unearned
  compensation..........      --          (5)          --               5 (H)          --
 Accumulated other
  comprehensive
  income................       (8)        (7)          --               7 (H)           (8)
                          -------     ------         -----         ------          -------
   Total stockholders'
    equity..............    6,137        659           --             660            7,456
                          -------     ------         -----         ------          -------
                          $28,744     $1,791         $(266)        $2,349          $32,618
                          =======     ======         =====         ======          =======
</TABLE>
 
   See accompanying Notes to Unaudited Pro Forma Combined Condensed Financial
                                  Statements.
 
                                       60
<PAGE>
 
                          Notes To Unaudited Pro Forma
 
                    Combined Condensed Financial Statements
 
1. Basis of Presentation
 
   The unaudited pro forma combined condensed financial statements have been
based upon Lockheed Martin's and COMSAT's historical consolidated financial
statements, and have been prepared to reflect the tender offer and the proposed
merger based on the purchase method of accounting. The unaudited pro forma
combined condensed statement of earnings for the year ended December 31, 1998
has been prepared to give effect to the tender offer and the merger as if they
had occurred at January 1, 1998. The unaudited pro forma combined condensed
balance sheet as of December 31, 1998 has been prepared to give effect to the
tender offer and the merger as if they had occurred on that date. Lockheed
Martin prepared the unaudited pro forma adjustments based upon financial data
provided by COMSAT, and upon preliminary estimates and assumptions that
management of Lockheed Martin believes are reasonable under the circumstances.
These pro forma financial statements have been reviewed by management of
COMSAT. While no material adjustments are expected to occur to the pro forma
financial statements based upon information currently available, events may
occur between now and completion of the merger, including among others,
developments concerning the privatization of INTELSAT, amendment of the
Satellite Act and other items discussed under the caption "Risk Factors," which
could materially affect the pro forma adjustments.
 
   The unaudited pro forma combined condensed financial statements are not
necessarily indicative of actual or future financial position or results of
operations that would have occurred or will occur upon the completion of the
tender offer and the merger. The unaudited pro forma combined condensed
financial statements are based upon and should be read in conjunction with the
historical consolidated financial statements of Lockheed Martin and COMSAT, and
the respective related notes, which are incorporated by reference in this proxy
statement/prospectus.
 
2. The Tender Offer and the Merger
 
A. Purchase Price
 
   As described in the merger agreement, the tender offer will involve the
purchase by Regulus of a non-controlling interest of up to 49%, subject to
certain adjustments, of the outstanding shares of COMSAT common stock at a
price of $45.50 per share. The merger will involve the exchange of each
remaining outstanding share of COMSAT common stock for the right to receive one
share of Lockheed Martin common stock. The computation of the purchase price
follows (in millions):
 
<TABLE>
      <S>                                                               <C>
      Purchase of 49% of outstanding common shares (25.7 million
       shares of COMSAT common stock at a price of $45.50 per share)..  $1,170
      Exchange of the remaining 51% of outstanding common shares (26.9
       million shares of COMSAT common stock at the conversion ratio
       of one share of Lockheed Martin common stock at an average
       market price of $49 per share as of the time that the terms of
       the transaction were announced)................................   1,319
      Assumption of COMSAT's stock options at an amount based on the
       difference between the average market price of Lockheed Martin
       common stock used above and the average exercise price of the
       outstanding options............................................      94
      Estimated transaction costs.....................................      25
                                                                        ------
      Total purchase price............................................  $2,608
                                                                        ======
</TABLE>
 
                                       61
<PAGE>
 
                          Notes To Unaudited Pro Forma
 
              Combined Condensed Financial Statements--(Continued)
 
 
 
B. Reclassifications
 
   Reclassifications have been reflected in the unaudited pro forma combined
condensed income statement and balance sheet to conform the presentation of
investments in affiliates, income tax balances, and other items to the format
used by Lockheed Martin.
 
C. Pro Forma Adjustments
 
   The following adjustments are provided to reflect the tender offer and
merger on a pro forma basis:
 
     (A) To eliminate sales and cost of sales between Lockheed Martin and
  COMSAT. No adjustments have been made to eliminate the related intercompany
  profit in ending inventories and the net intercompany receivables and
  payables at December 31, 1998, as such amounts are not considered material.
 
     (B) To record the amortization of cost in excess of net assets acquired
  (over a composite estimated life of 30 years), and the effects, net of
  state income tax benefits, of other estimated fair value adjustments,
  including those related to pensions and post-retirement benefit
  liabilities.
 
     (C) To record the amortization of the estimated fair value of
  investments in affiliates in excess of the underlying recorded values (over
  a composite estimated life of 30 years), net of state income tax benefits.
 
     (D) To record interest expense, using an estimated composite interest
  rate of 6.3%, resulting from the assumed issuance of an estimated $1,170
  million in debt obligations to complete the tender offer. If the assumed
  interest rate was changed by 1/8%, pro forma interest expense for the year
  ended December 31, 1998 would have changed by approximately $2 million.
 
     (E) To record the federal income tax effect, using the 35% statutory
  rate, related to the net pro forma adjustments other than the amortization
  of cost in excess of net assets acquired.
 
     (F) To record the assumed issuance of short-term borrowings and long-
  term debt obligations to finance the tender offer.
 
     (G) To adjust the assets and liabilities of COMSAT to their estimated
  fair values (such estimated fair values are subject to possible adjustment
  based on continued valuation analyses) as follows (in millions):
 
<TABLE>
      <S>                                                                <C>
      Net assets of COMSAT at December 31, 1998......................... $  659
      Estimated fair value adjustments:
        Deferred income tax assets......................................      9
        Other current assets............................................      2
        Investments in affiliates.......................................    980
        Other assets....................................................     41
        Other current liabilities.......................................    (40)
        Long-term debt..................................................    (21)
        Post-retirement benefit liabilities.............................     17
        Other liabilities...............................................   (356)
        Cost in excess of net assets acquired...........................  1,317
                                                                         ------
                                                                         $2,608
                                                                         ======
</TABLE>
 
                                       62
<PAGE>
 
                          Notes To Unaudited Pro Forma
 
              Combined Condensed Financial Statements--(Continued)
 
 
 
     (H) To eliminate COMSAT's historical equity balances, to record the
  assumed issuance of 26.9 million shares of Lockheed Martin common stock, at
  an average market price of $49 per share as of the time that the terms of
  the transaction were announced, to complete the merger, and to record
  accrued liabilities for the assumption of COMSAT's stock options, at an
  amount based on the difference between the average market price of Lockheed
  Martin common stock noted above and the average exercise price of the
  outstanding options, and estimated transaction costs.
 
3. Computation of Pro Forma Earnings Per Common Share
 
<TABLE>
<CAPTION>
                                                               Year Ended
                                                           December 31, 1998
                                                          --------------------
                                                          (In millions, except
                                                            per share data)
     <S>                                                  <C>
     Pro Forma Basic Earnings Per Common Share:
     Net earnings........................................        $  909
                                                                 ======
     Average number of common shares outstanding
      for basic earnings per share.......................         403.4
                                                                 ======
     Pro forma basic earnings per share..................        $ 2.25
                                                                 ======
     Pro Forma Diluted Earnings Per Common Share:
     Net earnings........................................        $  909
                                                                 ======
     Average number of common shares outstanding
      for basic earnings per share.......................         403.4
     Dilutive stock options--based on the treasury stock
      method.............................................           7.0
                                                                 ------
     Average number of common shares outstanding
      for diluted earnings per share.....................         410.4
                                                                 ======
     Pro forma diluted earnings per share................        $ 2.21
                                                                 ======
</TABLE>
 
                                       63
<PAGE>
 
                      COMPARISON OF SHAREHOLDERS' RIGHTS
 
   Upon completion of the merger, unless you properly exercise dissenters'
rights, you will become a Lockheed Martin shareholder. Your shareholder rights
will be governed by the Maryland General Corporation Law and Lockheed Martin's
charter and bylaws, which differ in a number of material respects from your
rights as a COMSAT shareholder under the District of Columbia Business
Corporation Act and COMSAT's articles of incorporation and bylaws. The
following tables summarize the principal differences between the rights of
COMSAT shareholders and Lockheed Martin shareholders. Copies of Lockheed
Martin's charter and bylaws and COMSAT's articles of incorporation and bylaws
are incorporated by reference into this proxy statement/prospectus, and copies
will be sent to you upon request. See "Where You Can Find More Information" on
page 105.
 
   Authorized Capital. The total number of authorized shares of capital stock
are as follows:
 
<TABLE>
<CAPTION>
                                         COMSAT             Lockheed Martin
                                  --------------------- -----------------------
                                  Par Value   Shares    Par Value    Shares
                                  --------- ----------- --------- -------------
   <S>                            <C>       <C>         <C>       <C>
   Common stock..................    --     100,000,000   $1.00   1,500,000,000
   Preferred stock...............    --       5,000,000     --              --
   Series A preferred stock......    --             --    $1.00      20,000,000
   Series preferred stock........    --             --    $1.00      50,000,000
   Total.........................           105,000,000           1,570,000,000
</TABLE>
 
  COMSAT Shareholders Lockheed Martin Shareholders
  ------------------- ----------------------------
Outstanding Capital   No class or series of          No class or series of
 Stock..............  COMSAT preferred stock is      Lockheed Martin preferred
                      currently outstanding.         stock is currently
                                                     outstanding.
 
                      COMSAT common stock is
                      issued in two series,
                      designated Series I and
                      Series II. Shares of
                      Series I common stock may
                      be issued only to persons
                      who are not authorized
                      carriers. Shares of Series
                      II common stock may be
                      issued only to authorized
                      carriers.
 
                      The Satellite Act provides
                      that only authorized
                      carriers may own more than
                      10% of the outstanding
                      shares of COMSAT common
                      stock. COMSAT's articles
                      of incorporation authorize
                      COMSAT's Board of
                      Directors to establish an
                      ownership limitation below
                      the 10% statutory maximum.
                      Under this authority,
                      COMSAT's Board of
                      Directors established the
                      ownership limitation at
                      10%. COMSAT's Board of
                      Directors also established
                      a voting limitation
                      preventing holders of more
                      than 5% but less than 10%
                      of COMSAT common stock
                      from voting shares above
                      the 5% threshold.
 
Number of
 Directors; Term of
 Office.............
                      COMSAT has 15 director         Lockheed Martin currently
                      positions, 12 of which are     has 15 directors.
                      elected annually by            Lockheed Martin's Board
                      COMSAT's shareholders for      of Directors may increase
                      one-year terms, and three      or decrease the number of
                      of which are appointed by      directors, so long as the
                      the President of the           Board is not decreased to
                      United States, with the        less than 12. Each
                      advice and consent of the      Lockheed Martin director
                      United States Senate, for      serves until the next
                      three-year terms. In           annual meeting of
 

                                      64
<PAGE>
 
  COMSAT Shareholders Lockheed Martin Shareholders
  ------------------- ----------------------------
                      each case, COMSAT             shareholders after his
                      directors serve until         election and until a
                      their successors have         successor has been
                      been appointed and            elected and qualified.
                      qualified.
 
Election of           COMSAT's bylaws provide       Lockheed Martin's
 Directors..........  that you are entitled to      charter provides for
                      cumulate your votes for       cumulative voting in the
                      the election of               election of directors
                      directors. Authorized         only in instances where
                      carrier holders of Series     a single shareholder
                      II common stock are           beneficially owns 40% or
                      entitled to vote              more of shares entitled
                      separately from holders       to vote for the election
                      of Series I common stock      of directors.
                      and elect from one to six
                      directors if the number
                      of shares of Series II
                      common stock outstanding
                      at the record date
                      constitutes 8% or more of
                      the total outstanding
                      shares of COMSAT common
                      stock.
 
Quorum of
Directors...........  Eight members of COMSAT's     A majority of the
                      Board of Directors are        members of Lockheed
                      generally required to         Martin's Board of
                      constitute a quorum.          Directors is generally
                                                    required to constitute a
                                                    quorum.
 
Removal of            None of District of           Lockheed Martin's
 Directors..........  Columbia law, COMSAT's        charter provides that
                      articles of incorporation     directors may be removed
                      or COMSAT's bylaws            at any time, but only
                      contain any provisions        for cause, by the
                      regarding the removal of      affirmative vote of at
                      directors.                    least 80% of the votes
                                                    that holders of
                                                    outstanding shares are
                                                    entitled to cast in the
                                                    election of directors,
                                                    voting together as one
                                                    class.
 
Filling Vacancies
 on the Board of
 Directors..........  Vacancies occurring may       Under Maryland law,
                      be filled by a majority       shareholders may elect a
                      vote of the remaining         successor to fill a
                      directors, unless             vacancy on the board of
                      otherwise provided in         directors created by the
                      COMSAT's articles of          removal of a director.
                      incorporation. A director     The successor elected by
                      elected to fill a vacancy     the shareholders serves
                      is elected for his            for the balance of the
                      predecessor's unexpired       removed director's term.
                      term.                         Under Maryland law, as
                                                    well as Lockheed
                                                    Martin's charter and
                                                    bylaws, a majority of
                                                    the remaining directors
                                                    may appoint a director
                                                    to fill a vacancy,
                                                    unless the vacancy is
                                                    caused by an increase in
                                                    the size of the Board of
                                                    Directors, in which case
                                                    the vacancy may be
                                                    filled only by majority
                                                    vote of the entire
                                                    Lockheed Martin Board of
                                                    Directors. A director
                                                    elected by the Board of
                                                    Directors to fill a
                                                    vacancy serves until the
                                                    next annual meeting of
                                                    shareholders and until
                                                    his successor is elected
                                                    and qualified.
 
                      COMSAT's articles of
                      incorporation provide
                      that vacancies of the
                      COMSAT Board of Directors
                      are filled as follows:
 
                      . vacancies among the
                        Presidential appointees
                        are filled by the
                        President;
 
                      . vacancies among
                        directors designated by
                        holders of Series II
                        common stock are filled
                        by a majority vote of
                        the remaining directors
                        designated by the
                        holders of Series II
                        common stock, subject
                        to the limitation on
                        the ability of any
                        single holder of Series
                        II common stock to vote
                        for more than three
                        directors; and
 
 
                                      65
<PAGE>

  COMSAT Shareholders Lockheed Martin Shareholders
  ------------------- ----------------------------
                       . vacancies among
                         directors designated by
                         holders of Series I
                         common stock are filled
                         by a majority vote of
                         the remaining directors
                         designated by the
                         holders of Series I
                         common stock.
 
Amendment to Charter
 or Articles of
 Incorporation.......  The affirmative vote of      Lockheed Martin's charter
                       two-thirds of the            provides that, except as
                       outstanding shares           described below, a
                       entitled to vote is          majority vote of the
                       required to amend COMSAT's   outstanding shares
                       articles of incorporation.   entitled to vote is
                                                    necessary to amend
                                                    Lockheed Martin's charter.
 
                       In addition, COMSAT's
                       articles of incorporation
                       provide that at least ten
                       days before a meeting of
                       COMSAT's Board of
                       Directors is called to
                       consider an amendment to
                       COMSAT's articles of
                       incorporation, notice of
                       the meeting, including a
                       statement of the proposed
                       amendment or of the
                       substance of the
                       amendment, must be
                       provided to each director,
                       the United States Attorney
                       General, the Chairman of
                       the FCC and other persons
                       designated by the
                       President of the United
                       States.
 
                                                    . The affirmative vote of
                                                      80% of the votes of the
                                                      holders of outstanding
                                                      shares entitled to vote
                                                      in the election of
                                                      directors is required to
                                                      amend Sections 3 or 5 of
                                                      Article V of Lockheed
                                                      Martin's charter
                                                      relating to removal of
                                                      directors and the
                                                    general powers of the
                                                    Board of Directors.
 
                                                    . Amendments to Article
                                                      XIII of Lockheed
                                                      Martin's charter
                                                      regarding business
                                                      combinations require the
                                                      affirmative vote of:
 
                                                      (a) 80% of the
                                                          outstanding shares
                                                          entitled to vote in
                                                          the election of
                                                          directors, and
 
                                                      (b) 67% of the
                                                          outstanding shares
                                                          entitled to vote in
                                                          the election of
                                                          directors, excluding
                                                          shares held by
                                                          beneficial owners of
                                                          10% or more of the
                                                          outstanding shares
                                                          of any class or
                                                          series of voting
                                                          stock, and any
                                                          affiliates or
                                                          associates of such
                                                          person,
 
                                                    unless the amendment is
                                                    approved in advance of
                                                    submission to the
                                                    shareholders by not less
                                                    than two-thirds of
                                                    Lockheed Martin's
                                                    continuing directors.
                                                    Continuing directors are
                                                    directors who were either
                                                    directors prior to the
                                                    time the related person
                                                    became a related person or
                                                    were designated continuing
                                                    directors by a majority of
                                                    the then continuing
                                                    directors.
 
                                                    . Amendments to Article
                                                      XIV of Lockheed Martin's
                                                      charter regarding
                                                      prohibitions on
                                                      greenmail and other
                                                      transactions requires
                                                      the affirmative vote of
                                                      80% of the votes
                                                      entitled to vote in the
                                                      election of directors.
 
Amendment of           Under COMSAT's articles of   Under Maryland law, the
Bylaws...............  incorporation and bylaws,    power to adopt, amend or
                       COMSAT's                     repeal a corporation's
                                                    bylaws is
 
                                       66
<PAGE>
 
  COMSAT Shareholders Lockheed Martin Shareholders
  ------------------- ----------------------------

                       bylaws may be altered,       vested in the
                       amended or repealed by a     corporation's
                       majority vote of COMSAT's    shareholders, except to
                       Board of Directors at a      the extent the
                       meeting called for that      corporation's charter or
                       purpose. At least five       bylaws vest it in the
                       days before the meeting,     board of directors.
                       notice of the meeting        Lockheed Martin's bylaws
                       stating the substance of     grant Lockheed Martin's
                       the amendment must be sent   Board of Directors
                       to the United States         exclusive power to adopt,
                       Attorney General, the        amend, alter or repeal
                       Chairman of the FCC and      Lockheed Martin's bylaws.
                       other persons designated
                       by the President of the
                       United States.
 
Advance Notice of
 Director
 Nominations and New
 Business............
                       COMSAT's bylaws provide      For annual or special
                       that, with respect to any    shareholders' meetings,
                       shareholder meeting,         Lockheed Martin's bylaws
                       nominations of persons for   provide that nominations
                       election to COMSAT's Board   of persons for election to
                       of Directors may be made     Lockheed Martin's Board of
                       only by a shareholder of     Directors and the proposal
                       record who is entitled to    of business to be
                       vote and who complies with   considered by shareholders
                       the advance notice           may be made only as
                       procedures set forth in      follows:
                       COMSAT's bylaws. In
                       addition, a director
                       nominee must file with
                       COMSAT's corporate
                       secretary a statement of
                       his interests in
                       communications common
                       carriers in the form
                       required by COMSAT's Board
                       of Directors.
 
                                                    . pursuant to Lockheed
                                                      Martin's notice of the
                                                      meeting,
 
                                                    . by or at the direction
                                                      of Lockheed Martin's
                                                      Board of Directors, or
 
                                                    . by a shareholder of
                                                      record who is entitled
                                                      to vote at the meeting
                                                      who complies with the
                                                      advance notice
                                                      procedures set forth in
                                                      Lockheed Martin's
                                                      bylaws.
 
                       COMSAT'S bylaws provide
                       that the proposal of
                       business at a shareholders
                       meeting may be made only
                       as follows:
 
                       . pursuant to COMSAT's
                         notice of the meeting,
 
                       . by or at the direction
                         of COMSAT'S Board of
                         Directors, or
 
                       . by a shareholder of
                         record who is entitled
                         to vote at the meeting
                         who complies with the
                         advance notice
                         procedures set forth in
                         COMSAT'S bylaws.
 
Shareholder Meetings
 and Notice
 Provisions..........  Under COMSAT's bylaws,       Under Lockheed Martin's
                       special shareholder          bylaws, special
                       meetings may be called at    shareholder meetings may
                       any time by COMSAT's Board   be called at any time by
                       of Directors, by             the Chairman of the Board,
                       resolution or written        the President, the
                       direction of three           Executive Committee of
                       members, the Chairman or     Lockheed Martin's Board of
                       Vice Chairman of COMSAT's    Directors, a majority of
                       Board of Directors, the      Lockheed Martin's Board of
                       President or the Secretary   Directors or by the
                       of COMSAT or by holders of   Secretary at the written
                       not less than one-fifth of   request of shareholders
                       all shares of stock          entitled to cast at least
                       outstanding and entitled     a majority of the votes
                       to vote at the meeting.      entitled to be cast at the
                                                    meeting. Under Maryland
                                                    law, unless requested by
                                                    the shareholders entitled
                                                    to cast a majority of all
                                                    the votes at the meeting,
                                                    a special meeting of
                                                    shareholders need not be
 
                       COMSAT's bylaws provide
                       that notice of a
                       shareholders meeting must
                       be delivered to
                       shareholders entitled to
                       vote at the
 
                                       67
<PAGE>
 
  COMSAT Shareholders Lockheed Martin Shareholders
  ------------------- ----------------------------

                       meeting not less than 10     called to consider any
                       nor more than 50 days        matter that is
                       before the date of the       substantially the same as
                       meeting.                     a matter voted on at a
                                                    special meeting held
                                                    within the preceding 12
                                                    months.
 
                                                    Lockheed Martin's bylaws
                                                    provide that notice of a
                                                    shareholders meeting must
                                                    be delivered to
                                                    shareholders not less than
                                                    30 nor more than 90 days
                                                    before the meeting.
 
Voting by              Except for the election of   Under Lockheed Martin's
Shareholders.........  directors and as otherwise   charter, except for
                       provided by statute or       amending a number of
                       COMSAT's articles of         provisions of the charter,
                       incorporation or bylaws,     or as otherwise provided
                       action by COMSAT             in the charter or by
                       shareholders generally is    applicable law, action by
                       taken by a majority vote     Lockheed Martin
                       of the outstanding shares    shareholders generally is
                       present in person or         taken by a majority vote,
                       represented by proxy and     at a meeting at which a
                       entitled to vote. A number   quorum is present. A
                       of extraordinary actions,    number of extraordinary
                       including mergers,           actions, including
                       consolidations and charter   mergers, consolidations
                       amendments, require the      and charter amendments,
                       affirmative vote of two-     that under Maryland law
                       thirds of the votes          would, absent provision in
                       entitled to be cast on the   Lockheed Martin's charter,
                       matter.                      require the affirmative
                                                    vote of two-thirds of the
                                                    votes entitled to be cast
                                                    on the matter, are taken
                                                    by a majority vote of all
                                                    votes entitled to be cast
                                                    on the matter.
 
Shareholder Action
 Without a Meeting...
                       Under District of Columbia   Under Maryland law, any
                       law, any action required     action required or
                       or permitted to be taken     permitted to be taken at a
                       at a meeting of              meeting of shareholders
                       shareholders may be taken    may be taken without a
                       without a meeting if a       meeting only if a
                       consent in writing setting   unanimous written consent
                       forth the actions so taken   is signed by each
                       is signed by all of the      shareholder entitled to
                       shareholders entitled to     vote on the matter and a
                       vote on the matter and the   written waiver of any
                       consent is filed with the    right to dissent is signed
                       corporate minutes.           by each shareholder who
                                                    would have been entitled
                                                    to notice of, but could
                                                    not vote at, the meeting.
 
Business               The District of Columbia     Under Maryland law, a
Combinations.........  does not have a business     number of business
                       combination statute.         combinations between a
                                                    Maryland corporation and:
 
                                                    . any person who
                                                      beneficially owns 10% or
                                                      more of the voting power
                                                      of the corporation's
                                                      shares,
 
                                                    . an affiliate of the
                                                      corporation who, at any
                                                      time within the two-year
                                                      period before the date
                                                      in question, was the
                                                      beneficial owner of 10%
                                                      or more of the voting
                                                      power of the then-
                                                      outstanding voting stock
                                                      of the corporation, or
 
                                                    . any affiliate of an
                                                      interested shareholder,
 
                                                    are prohibited for five
                                                    years after the
                                                    most recent date on which
                                                    the interested shareholder
                                                    became an interested
 
                                       68
<PAGE>
 
  COMSAT Shareholders Lockheed Martin Shareholders
  ------------------- ----------------------------

                                                    shareholder, and after
                                                    that time must be
                                                    recommended by the board
                                                    of directors of the
                                                    corporation and approved
                                                    by:
 
                                                    (a) the affirmative vote
                                                        of at least 80% of the
                                                        votes entitled to be
                                                        cast by holders of its
                                                        outstanding voting
                                                        shares voting together
                                                        as a single voting
                                                        group, and
 
                                                    (b) two-thirds of the
                                                        votes entitled to be
                                                        cast by holders of the
                                                        outstanding voting
                                                        shares, other than
                                                        shares held by the
                                                        interested shareholder
                                                        with whom the business
                                                        combination is to be
                                                        effected;
 
                                                    unless the "fair price"
                                                    provisions are complied
                                                    with or the business
                                                    combination is either
                                                    approved or exempted by
                                                    the board of directors
                                                    before the interested
                                                    shareholder becomes an
                                                    interested shareholder.
                                                    Business combinations
                                                    include mergers,
                                                    consolidations, share
                                                    exchanges or, in certain
                                                    circumstances, asset
                                                    transfers or issuances or
                                                    reclassifications of
                                                    equity securities.
 
                                                    In addition to Maryland
                                                    law requirements, Lockheed
                                                    Martin's charter also
                                                    contains a provision
                                                    requiring that any
                                                    business combination
                                                    between Lockheed Martin
                                                    and a related person must
                                                    be approved by 80% of the
                                                    outstanding shares of
                                                    voting stock and by not
                                                    less than 67% of the
                                                    outstanding shares of
                                                    voting stock not owned by
                                                    the related person. This
                                                    provision does not apply
                                                    to a business combination
                                                    approved by a two-thirds
                                                    vote of the continuing
                                                    directors or if the
                                                    consideration received by
                                                    the shareholders other
                                                    than the related person is
                                                    not less than the highest
                                                    price per share paid by
                                                    the related person before
                                                    the business combination
                                                    and a proxy statement
                                                    complying with the
                                                    regulations of the
                                                    Exchange Act shall have
                                                    been sent to all
                                                    shareholders. Under
                                                    Lockheed Martin's charter,
                                                    this provision may be
                                                    amended only by the same
                                                    two supermajority votes
                                                    required for approval of a
                                                    business combination.
 
                                                    The business combination
                                                    statute could have the
                                                    effect of discouraging
                                                    unsolicited offers to
                                                    acquire Lockheed Martin
                                                    and of increasing the
                                                    difficulty of consummating
                                                    an unsolicited offer.
 
                                       69
<PAGE>
 
  COMSAT Shareholders Lockheed Martin Shareholders
  ------------------- ----------------------------

Control Share          The District of Columbia     Maryland law provides that
Acquisitions.........  does not have a control      control shares of a
                       share acquisition statute.   Maryland corporation
                                                    acquired in a control
                                                    share acquisition have no
                                                    voting rights except to
                                                    the extent approved by a
                                                    vote of two-thirds of the
                                                    votes entitled to be cast
                                                    by shareholders, excluding
                                                    shares of stock as to
                                                    which the acquiring
                                                    person, officers of the
                                                    corporation and directors
                                                    of the corporation who are
                                                    employees of the
                                                    corporation are entitled
                                                    to exercise or direct the
                                                    exercise of the voting
                                                    power of the shares in the
                                                    election of directors.
 
                                                    Control shares are voting
                                                    shares of stock that, if
                                                    aggregated with all other
                                                    shares of stock previously
                                                    acquired by a person,
                                                    would entitle the
                                                    acquiring person to
                                                    exercise voting power in
                                                    electing directors within
                                                    one of the following
                                                    ranges of voting power:
 
                                                    . one-fifth or more but
                                                      less than one-third,
 
                                                    . one-third or more but
                                                      less than a majority or
 
                                                    . a majority of all voting
                                                      power.
 
                                                    Control shares do not
                                                    include shares which the
                                                    acquiring person is
                                                    entitled to vote as a
                                                    result of having
                                                    previously obtained
                                                    shareholder approval. A
                                                    control share acquisition
                                                    generally means the
                                                    acquisition of control
                                                    shares.
 
                                                    A person who has made or
                                                    proposes to make a control
                                                    share acquisition, upon
                                                    satisfaction of a number
                                                    of conditions, may compel
                                                    the board of directors to
                                                    call a special meeting of
                                                    shareholders to be held
                                                    within 30 to 50 days of
                                                    the demand to consider the
                                                    voting rights of the
                                                    control shares.
 
                                                    If voting rights are not
                                                    approved at the meeting or
                                                    if an acquiring person
                                                    statement has been
                                                    delivered as required by
                                                    Maryland law, then, in
                                                    general, the corporation
                                                    may redeem any or all of
                                                    the control shares, except
                                                    those for which voting
                                                    rights have previously
                                                    been approved, for fair
                                                    value determined, without
                                                    regard to voting rights,
                                                    as of the date of the last
                                                    control share acquisition
                                                    or of any meeting of
                                                    shareholders at which the
                                                    voting rights of the
                                                    control shares are
                                                    considered and not
                                                    approved. If voting rights
                                                    for control shares are
 
                                       70
<PAGE>
 
  COMSAT Shareholders Lockheed Martin Shareholders
  ------------------- ----------------------------

                                                    approved at a shareholders
                                                    meeting and the acquiring
                                                    person becomes entitled to
                                                    vote a majority of the
                                                    shares entitled to vote,
                                                    all other shareholders may
                                                    exercise appraisal rights.
                                                    The fair value of the
                                                    shares as determined for
                                                    purposes of appraisal
                                                    rights may not be less
                                                    than the highest price per
                                                    share paid in the control
                                                    share acquisition.
 
                                                    The control share
                                                    acquisition statute does
                                                    not apply to shares
                                                    acquired in a merger,
                                                    consolidation or share
                                                    exchange if the
                                                    corporation is a party to
                                                    the transaction or to
                                                    acquisitions approved or
                                                    excepted by the charter or
                                                    the bylaws of the
                                                    corporation.
 
                                                    The control share
                                                    acquisition statute could
                                                    have the effect of
                                                    discouraging unsolicited
                                                    offers to acquire Lockheed
                                                    Martin and of increasing
                                                    the difficulty of
                                                    consummating an
                                                    unsolicited offer.
 
Indemnification and
 Limitation of
 Liability...........
                       Under District of Columbia   Lockheed Martin's charter
                       law a corporation has the    limits the monetary
                       power to indemnify its       liability of both officers
                       current and former           and directors to the
                       directors and officers and   maximum extent permissible
                       other people who may have    under Maryland law. To the
                       served at the                extent that it is proved
                       corporation's request as a   that the person received
                       director or officer of       an improper benefit or
                       another corporation in       profit in money, property
                       which the corporation owns   or services, the liability
                       shares of capital stock or   limitation is not
                       of which it is a creditor    applicable for the amount
                       against expenses actually    of benefit or profit so
                       and necessarily incurred     received. In addition, the
                       by them in connection with   liability limitation is
                       the defense of any           not applicable if a
                       proceeding in which they     judgment or other final
                       are a party, by reason of    adjudication adverse to
                       being or having been a       the person is entered in a
                       director or officer of the   proceeding based on a
                       corporation, or of another   finding that the person's
                       corporation, except in       action or failure to act
                       relation to matters as to    was the result of active
                       which the person shall be    and deliberate dishonesty
                       adjudged in the proceeding   and was material to the
                       to be liable for             cause of action.
                       negligence or misconduct
                       in the performance of
                       duty.
 
                                                    Under Maryland law, unless
                                                    limited by the charter,
                                                    indemnification is
                                                    mandatory if a director or
                                                    an officer is successful
                                                    on the merits or otherwise
                                                    in the defense of any
                                                    proceeding by reason of
                                                    his service as a director
                                                    or officer unless
                                                    indemnification is not
                                                    otherwise permitted as
                                                    described in the following
                                                    sentence. Indemnification
                                                    is permissive unless it is
                                                    established that:
 
                       COMSAT's articles of
                       incorporation provide
                       that, to the fullest
                       extent permitted by law,
                       any person who was or is a
                       party to any proceeding
                       brought by COMSAT, by
                       reason of the fact that
                       the person is a director,
                       advisory director or
                       officer of COMSAT, or by
                       reason of any action
                       alleged to have been taken
                       or omitted in that
                       capacity, shall be
                       indemnified, against
                       costs, reasonably incurred
                       by him in connection with
                       the defense or settlement
                       of any proceeding;
                       provided that no
                       indemnification will be
 
                                                    . the act or omission of
                                                      the director or officer
                                                      was material to the
                                                      matter giving rise to
                                                      the proceeding and was
                                                      committed in bad faith
                                                      or was the result of
                                                      active and deliberate
                                                      dishonesty,
 
 
                                       71
<PAGE>
 
  COMSAT Shareholders Lockheed Martin Shareholders
  ------------------- ----------------------------

                       made in any matter where     . the director or officer
                       the person will have been      actually received an
                       judged liable for              improper personal
                       negligence or misconduct       benefit in money,
                       in the performance of          property or services, or
                       duty. COMSAT's Board of
                       Directors may indemnify
                       other persons.
 
                                                    . in the case of a
                                                      criminal proceeding, the
                                                      director or officer had
                                                      reasonable cause to
                                                      believe his act or
                                                      omission was unlawful.
 
                       COMSAT's articles of
                       incorporation provide
                       that, to the full extent
                       permitted by law, upon
                       request, COMSAT shall pay
                       costs, charges and
                       expenses incurred by any
                       person entitled to
                       indemnification in advance
                       of the final disposition
                       of any proceeding upon
                       receipt of an undertaking
                       by or on behalf of the
                       person to repay all
                       amounts so advanced in the
                       event that it shall
                       ultimately be determined
                       that he is not entitled to
                       be indemnified. COMSAT may
                       also pay the costs,
                       charges and expenses
                       incurred by any other
                       person COMSAT indemnifies.
 
                                                    In addition to the
                                                    foregoing, a court may
                                                    order indemnification if
                                                    it determines that the
                                                    director or officer is
                                                    fairly and reasonably
                                                    entitled to
                                                    indemnification in view of
                                                    all the relevant
                                                    circumstances, whether or
                                                    not the director or
                                                    officer has met the
                                                    standards of conduct set
                                                    forth in the preceding
                                                    sentence or has been
                                                    adjudged liable on the
                                                    basis that a personal
                                                    benefit was improperly
                                                    received in a proceeding
                                                    charging improper personal
                                                    benefit to the director or
                                                    the officer. If the
                                                    proceeding was an action
                                                    by or in the right of the
                                                    corporation or involved a
                                                    determination that the
                                                    director or officer
                                                    received an improper
                                                    personal benefit, however,
                                                    no indemnification may be
                                                    made if the individual is
                                                    adjudged liable to the
                                                    corporation, except to the
                                                    extent of expenses
                                                    approved by a court.
 
                                                    Under Maryland law, where
                                                    indemnification is
                                                    permissible, it must be
                                                    authorized by:
 
                                                    . a majority vote of a
                                                      quorum consisting of
                                                      directors who are not
                                                      parties to the
                                                      proceeding, or a
                                                      majority vote of a
                                                      disinterested committee
                                                      of the board if a quorum
                                                      cannot be obtained;
 
                                                    . special legal counsel
                                                      selected by the board of
                                                      directors or by a
                                                      committee of the board,
                                                      or a majority of the
                                                      full board if a quorum
                                                      of the board cannot be
                                                      obtained and the
                                                      committee cannot be
                                                      established; or
 
                                                    . a vote of the
                                                      shareholders other than
                                                      those shareholder-
                                                      directors who are party
                                                      to the proceedings.
 
                                                    Under Maryland law,
                                                    expenses may be advanced
                                                    to a director, and to an
                                                    officer, employee or agent
                                                    who is not a director, to
                                                    the same extent that they
                                                    may be advanced to a
                                                    director, unless limited
                                                    by the charter. Advances
                                                    to officers, employees and
                                                    agents may be generally
                                                    authorized in the
                                                    corporation's charter or
                                                    bylaws, by action of the
                                                    board of directors or by
                                                    contract.
 
                                       72
<PAGE>
 

  COMSAT Shareholders Lockheed Martin Shareholders
  ------------------- ----------------------------

Dissenters' or
 Appraisal Rights....
                       Under District of Columbia   Under Maryland law,
                       law, if you do not consent   shareholders have the
                       to a merger or               right to demand and to
                       consolidation and follow     receive payment of the
                       all required procedures,     fair value of their stock
                       you are entitled to          in the event of:
                       appraisal rights under
                       which you may receive cash
                       in the amount of the fair
                       market value of your
                       shares instead of the
                       consideration you would
                       otherwise receive in the
                       transaction. Under
                       District of Columbia law,
                       appraisal rights are
                       available to you in
                       connection with the
                       merger.
 
                                                    . a merger or
                                                      consolidation,
 
                                                    . a share exchange,
 
                                                    . certain sales of all or
                                                      substantially all of the
                                                      assets,
 
                                                    . a charter amendment
                                                      altering contract rights
                                                      of outstanding stock, as
                                                      expressly set forth in
                                                      the charter, and
                                                      substantially adversely
                                                      affecting the
                                                      shareholder's rights,
                                                      unless, as is the case
                                                      with Lockheed Martin's
                                                      charter, the right to do
                                                      so is reserved in the
                                                      charter, or
 
                                                    . certain business
                                                      combinations with
                                                      interested shareholders
                                                      that are subject to or
                                                      exempted from Maryland's
                                                      business combination
                                                      statute and in
                                                      connection with the
                                                      approval of voting
                                                      rights of certain
                                                      shareholders under
                                                      Maryland's control share
                                                      acquisition statute.
 
                                                    Except with respect to
                                                    certain business
                                                    combinations and in
                                                    connection with appraisal
                                                    and dissenters' rights
                                                    existing as a result of
                                                    Maryland's control share
                                                    acquisition statute, the
                                                    right to demand and
                                                    receive payment of fair
                                                    value does not apply to
                                                    the following:
 
                                                    . stock listed on a
                                                      national securities
                                                      exchange or NASDAQ;
 
                                                    . stock of the successor
                                                      in a merger, unless the
                                                      merger alters the
                                                      contract rights of the
                                                      stock and the charter
                                                      does not reserve the
                                                      right to do so or
                                                      converts the stock in
                                                      whole or in part into
                                                      something other than
                                                      stock, cash, scrip or
                                                      other interests, or
 
                                                    . stock of an open-end
                                                      investment company
                                                      registered with the SEC
                                                      under the Investment
                                                      Company Act of 1940 and
                                                      the stock is valued in
                                                      the transaction at its
                                                      net asset value.
 
                                                    Except in the case of
                                                    appraisal and dissenters'
                                                    rights existing as a
                                                    result of Maryland's
                                                    control share acquisition
                                                    statute, these rights are
                                                    available only when the
                                                    shareholder files with the
                                                    corporation a timely,
                                                    written objection to
 
                                       73
<PAGE>
 
  COMSAT Shareholders Lockheed Martin Shareholders
  ------------------- ----------------------------

                                                    the transaction and does
                                                    not vote in favor of the
                                                    transaction. In addition,
                                                    the shareholder must make
                                                    a demand on the successor
                                                    corporation for payment of
                                                    the stock within 20 days
                                                    of the acceptance of
                                                    articles of incorporation
                                                    by the state.
 
Prohibition on
 Payment of
 Greenmail...........  COMSAT's articles of         Lockheed Martin's charter
                       incorporation do not         contains a provision
                       contain a prohibition on     requiring approval by the
                       the payment of greenmail.    affirmative vote of
                                                    holders of a majority of
                                                    outstanding shares of
                                                    voting stock of any
                                                    purchase by Lockheed
                                                    Martin of shares of stock
                                                    entitled to vote from an
                                                    owner of 5% or more of
                                                    outstanding shares of
                                                    voting stock who
                                                    beneficially owned the
                                                    shares for less than two
                                                    years at a price per share
                                                    in excess of the market
                                                    price for the shares at
                                                    such time. Approval is
                                                    also required for certain
                                                    other transactions with
                                                    the shareholder,
                                                    including, but not limited
                                                    to, a merger or
                                                    consolidation, or the sale
                                                    or transfer of more than
                                                    $10 million of assets or
                                                    equity securities. In
                                                    either case, shares owned
                                                    the beneficial owner of 5%
                                                    or more of outstanding
                                                    shares of voting stock are
                                                    not permitted to vote or
                                                    taken into account. Under
                                                    Lockheed Martin's charter,
                                                    this provision may be
                                                    amended or repealed only
                                                    by the affirmative vote of
                                                    holders of at least 80% of
                                                    the outstanding shares of
                                                    voting stock.
 
                                                    Lockheed Martin's charter
                                                    further provides that if
                                                    any person other than
                                                    Lockheed Martin or certain
                                                    of its affiliates
                                                    beneficially owns voting
                                                    stock representing 40% or
                                                    more of the votes entitled
                                                    to be cast by all the
                                                    holders of outstanding
                                                    shares of voting stock,
                                                    the directors of Lockheed
                                                    Martin will be elected by
                                                    cumulative voting and one
                                                    or more candidates may be
                                                    nominated by certain
                                                    disinterested directors,
                                                    or by any beneficial owner
                                                    of voting stock having an
                                                    aggregate market price of
                                                    $250,000 or more.
 
Dividends............  District of Columbia law     Maryland law permits a
                       permits a corporation to     corporation to make a
                       declare and pay dividends    distribution, including
                       except when the              dividends, redemptions or
                       corporation is insolvent     stock repurchases, unless
                       or its net assets are less   prohibited by its charter
                       than its stated capital,     or, if following the
                       or when the dividend         distribution, the
                       payments would render the    corporation would not be
                       corporation insolvent or     able to pay its debts in
                       reduce its net assets        the ordinary course as
                       below its stated capital.    they become due or the
                                                    corporation's total assets
                                                    would be less
 
                                       74
<PAGE>
 
  COMSAT Shareholders Lockheed Martin Shareholders
  ------------------- ----------------------------

                                                    than the sum of its
                                                    liabilities and, unless
                                                    the charter provides
                                                    otherwise, senior
                                                    liquidation preferences.
                                                    For purposes of
                                                    determining whether a
                                                    distribution is lawful,
                                                    the corporation's assets
                                                    may be based upon fair
                                                    value or any other method
                                                    of valuation that is
                                                    reasonable under the
                                                    circumstances.
 
Right to Examine
 Shareholder List....
                       Under District of Columbia   Under Maryland law, any
                       law, record holders of at    one or more persons who
                       least 5% of all the          for at least six months
                       outstanding shares of a      have been the record
                       corporation are entitled     holders of at least 5% of
                       to examine and copy a        any class of stock are
                       corporation's shareholder    entitled to inspect and
                       list. In accordance with     copy the corporation's
                       the Satellite Act,           stock ledger and if the
                       COMSAT's articles of         corporation does not
                       incorporation provide that   maintain its stock ledger
                       any COMSAT shareholder has   at its principal place of
                       the right to examine and     business, to request in
                       copy COMSAT's shareholder    writing a shareholder
                       list. In addition,           list. Following the
                       COMSAT's bylaws provide      request, the corporation
                       that at least five days      has 20 days to produce a
                       before each shareholders     shareholder list with
                       meeting, the corporate       names, addresses and
                       secretary must prepare a     numbers of shares of each
                       shareholders list.           class owned. In addition,
                                                    under Lockheed Martin's
                                                    bylaws, the corporate
                                                    secretary must furnish a
                                                    shareholder list at each
                                                    meeting.
 
Interested Director
 Transactions........
                       The District of Columbia     Under Maryland law,
                       does not have any            certain contracts or
                       provisions regulating        transactions in which one
                       interested director          or more of a corporation's
                       transactions. However,       directors has an interest
                       COMSAT's articles of         are not void or voidable
                       incorporation provide that   by virtue of the interest
                       no director may              of the corporation's
                       participate in the           directors if ratified by a
                       negotiation of any           majority of disinterested
                       contract between COMSAT      shareholders or a majority
                       and any entity in which      of disinterested members
                       the director has a           of the board of directors
                       substantial financial        or a committee of the
                       interest or of which the     board if the material
                       interested director is a     facts are disclosed or
                       director, trustee or         known by the board or the
                       employee. A director has a   contract or transaction
                       duty to advise COMSAT's      was fair and reasonable to
                       Board of Directors or any    the corporation at the
                       committee of the board of    time it was approved.
                       any interest the director
                       has in a contract that
                       COMSAT's Board of
                       Directors or committee
                       propose to act upon at a
                       meeting at which the
                       director will not be
                       present and, if the
                       director is present, at
                       the meeting he must advise
                       COMSAT's Board of
                       Directors or committee of
                       his interest and abstain
                       from participation in any
                       discussion of or vote upon
                       the contract. If a
                       director knowingly
                       violates the foregoing and
                       the contract was unfair to
                       COMSAT at the time it was
                       entered into, the director
                       is liable to COMSAT for
                       any damages that result
                       from the unfairness.
 
                                       75
<PAGE>
 
  COMSAT Shareholders Lockheed Martin Shareholders
  ------------------- ----------------------------

Preemptive Rights....  Under District of Columbia   Under Maryland law as in
                       law, the preemptive right    effect at the time
                       of a shareholder to          Lockheed Martin was
                       acquire additional shares    incorporated, subject to
                       of a corporation             several statutory
                       may be limited or denied     exceptions, the preemptive
                       to the extent provided in    right of a shareholder to
                       a corporation's charter.     acquire additional shares
                       COMSAT's articles of         of a corporation could be
                       incorporation expressly      limited or denied to the
                       deny preemptive rights to    extent provided in a
                       shareholders.                corporation's charter.
                                                    Lockheed Martin's charter
                                                    denies preemptive rights
                                                    to holders of any class of
                                                    stock.
 
Unsolicited            The District of Columbia     The Maryland legislature
Takeovers............  does not have an             has passed a bill
                       unsolicited takeovers        regarding unsolicited
                       statute.                     takeovers which, if signed
                                                    by Maryland's Governor,
                                                    would become effective on
                                                    June 1, 1999. Under the
                                                    proposed bill, Maryland
                                                    corporations may elect to
                                                    be subject to any or all
                                                    of its provisions by a
                                                    resolution of the board of
                                                    directors or a provision
                                                    in its charter or bylaws.
                                                    Currently, Lockheed
                                                    Martin's Board of
                                                    Directors has not
                                                    considered whether it will
                                                    elect to be subject to any
                                                    or all of the provisions
                                                    in the bill. The proposed
                                                    bill contains the
                                                    following provisions:
 
                                                    . The board of directors
                                                      may establish a
                                                      stockholder rights plan
                                                      or "poison pill."
 
                                                    . A corporation electing
                                                      to be subject to the
                                                      bill must divide its
                                                      board of directors into
                                                      3 classes with each
                                                      class serving a
                                                      staggered 3 year term.
 
                                                    . Removal of a director on
                                                      a staggered board must
                                                      be for cause and
                                                      requires a two-thirds
                                                      vote of all votes
                                                      entitled to be cast by
                                                      shareholders generally
                                                      in the election of
                                                      directors.
 
                                                    . The number of directors
                                                      may be fixed only by the
                                                      board of directors.
 
                                                    . The secretary may call a
                                                      special shareholders
                                                      meeting only on the
                                                      written request of
                                                      shareholders entitled to
                                                      cast at least a majority
                                                      of the votes entitled to
                                                      be cast at the meeting
                                                      that satisfy certain
                                                      procedural requirements.
 
                                       76
<PAGE>
 
                        OWNERSHIP OF COMSAT COMMON STOCK
 
Record Date
 
   On April 30, 1999, the record date, there were approximately 52,695,937
shares of COMSAT common stock outstanding. Of this number, 18,958 were Series
II shares and approximately 52,676,979 were Series I shares. Series II shares
are shares held by FCC authorized communications common carriers. Series I
shares are held by other persons.
 
Beneficial Ownership of Principal Shareholders and Management
 
 Beneficial Owners.
 
   COMSAT has reviewed the Schedules 13G or 13D filed with the SEC as of April
1, 1999, the most recent practicable date for this 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>
Name and Address                         Amount and Nature of
of Beneficial Owner                     Beneficial Ownership(1) Percent of Class
- --------------------------------------- ----------------------- ----------------
<S>                                     <C>                     <C>
FMR Corp(2)............................        3,975,812              7.55%
Cramer Rosenthal McGlynn(3)............        3,485,955              6.62
Morgan Stanley
 Dean Witter & Co.(4)..................        3,355,632              6.37
</TABLE>
- --------
(1) Each number in this column has been rounded to the nearest whole share.
(2) FMR Corp., a Massachusetts corporation, is located at 82 Devonshire Street,
    Boston, Massachusetts 02109. FMR filed an amendment to its Schedule 13D 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) Cramer Rosenthal McGlynn, a New York limited liability company, is located
    at 707 Westchester Avenue, White Plains, New York 10604. The company filed
    a Schedule 13G on March 15, 1999 reporting beneficial ownership of
    3,485,955 shares of COMSAT common stock.
(4) 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 13G 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 April 1, 1999, the most
recent practicable date for this 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.
 
                                       77
<PAGE>
 
<TABLE>
<CAPTION>
                                                        Amount and Nature of
      Name(1)                                          Beneficial Ownership(2)
      ------------------------------------------------ -----------------------
      <S>                                              <C>
      Betty C. Alewine................................          388,160(3)
      Marcus C. Bennett...............................            2,480
      Lucy Wilson Benson..............................           40,485
      Edwin I. Colodny................................           47,749
      Lawrence S. Eagleburger.........................           13,102
      Allen E. Flower.................................          124,019(4)
      Neal B. Freeman.................................           32,165
      Caleb B. Hurtt..................................            8,441
      Dwight E. Jasmann...............................            9,492(5)
      Peter S. Knight.................................           13,402
      Peter W. Likins.................................           38,335(6)
      Charles T. Manatt...............................           13,902
      John H. Mattingly...............................           47,870(7)
      Benjamin A. Pontano.............................           48,813(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.................................          171,955(11)
      All directors and executive officers as a group
       (22 persons)...................................        3,102,889(12)
</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 COMSAT'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
     April 1, 1999 through the exercise of options as follows: Mrs. Alewine,
     266,743 shares; Mr. Bennett, 2,480 shares; Mrs. Benson, 34,725 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, 827,988
     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 1,553
     shares which are held in COMSAT's Savings and Profit-Sharing Plan as of
     April 1, 1999.
 (4) Includes 12,957 shares which are restricted against transfer and 1,294
     shares which are held in COMSAT's Savings and Profit-Sharing Plan as of
     April 1, 1999.
 (5) Includes 42 shares which are held in COMSAT's Savings and Profit-Sharing
     Plan as of April 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 1,099
     shares which are held in COMSAT's Savings and Profit-Sharing Plan as of
     April 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 616 shares
     which are held in COMSAT's Savings and Profit-Sharing Plan as of April 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 COMSAT's outstanding common stock as of April
     1, 1999.
(11) Includes 13,453 shares which are restricted against transfer and 1,458
     shares which are held in COMSAT's Savings and Profit-Sharing Plan as of
     April 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 6,554 shares which are held in COMSAT's
     Savings and Profit-Sharing Plan as of April 1, 1999. All directors and
     executive officers as a group beneficially owned 5.89% of COMSAT's
     outstanding common stock as of April 1, 1999.
 
                                       78
<PAGE>
 
Ownership and Voting Limitations
 
   To ensure that COMSAT common stock is widely held, there are specific
limitations on ownership of COMSAT common stock. The Satellite Act provides
that, unless you are a communications common carrier authorized to hold shares
by the FCC, no shareholder, or any syndicate or affiliated group of
shareholders, may own more than 10% of the aggregate number of outstanding
shares of COMSAT common stock.
 
   COMSAT's articles of incorporation authorize its Board of Directors to
establish an ownership limitation on COMSAT common stock below this 10%
statutory maximum. The COMSAT Board of Directors has set the ownership
limitation at 10% and has also established a voting limitation of 5%. The
voting limitation means that shares owned in excess of the 5% limitation, but
not in excess of the 10% limitation, may not be voted by the shareholder. These
excess shares will be voted proportionately with all other shares of COMSAT
common stock voted on any given matter.
 
                         ITEM 2. ELECTION OF DIRECTORS
 
Board of Directors
 
 Composition.
 
   The Satellite Act provides that the COMSAT Board of Directors will consist
of 15 directors. Of these, 12 are to be elected annually by the shareholders
for terms of one year. The remaining 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 and, in each case, until their successors have been appointed
and qualified.
 
 Attendance.
 
   The COMSAT Board of Directors met eight times in 1998. All incumbent
directors, except Mr. Eagleburger, attended 75% or more of the meetings of the
Board of Directors and the meetings of committees of the Board of Directors of
which they were members in 1998.
 
Voting for Directors
 
 Voting at the Annual Meeting.
 
   At the annual meeting, 12 directors will be elected to serve until the 2000
Annual Meeting of COMSAT shareholders. This year all shareholders will vote
together for the election of directors because the number of Series II shares
outstanding on April 30, 1999, the record date, constituted less than 8% of the
total outstanding shares on that date, as required under the Satellite Act.
 
   COMSAT's management has been authorized by the Board of Directors to solicit
proxies in favor of the election of the 12 nominees listed in this proxy
statement/prospectus. For biographical information about these nominees, please
refer to "Nominees For Election As Directors" on page 81. Each of these
nominees currently serves as a director. For biographical information about the
two Presidentially-appointed directors, please refer to "Presidentially-
Appointed Directors" on page 83.
 
 Your Voting Options.
 
   You may vote the total number of shares of COMSAT common stock you hold for
each of 12 nominees. Alternatively, you may cumulate your votes. This means
that you may give one nominee a total number of votes equal to the number of
shares you hold multiplied by 12. Or, you may distribute this total number of
votes among any number of nominees not exceeding 12. In any case, if you own
more than 5% of COMSAT's common stock, you will have to comply with the 5%
voting limitation described under "Ownership of COMSAT Common Stock."
 
                                       79
<PAGE>
 
   If you leave the Election of Directors section of your proxy card blank,
your shares will be voted for the 12 nominees listed on the proxy card. COMSAT
does not currently expect that any of the 12 nominees will become unavailable
for election. If this changes, the proxy holders will designate a substitute
nominee and will vote the shares represented by proxies for this substitute
nominee. The proxy holders may decide to vote the shares cumulatively for fewer
than 12 of the nominees.
 
 Shareholders Agreement.
 
   Under the shareholders agreement with Lockheed Martin, COMSAT has agreed
that, if the tender offer is completed, three individuals designated by
Lockheed Martin will be elected to the COMSAT Board of Directors and one of the
three individuals will be appointed to serve on each committee of the COMSAT
Board of Directors. It is anticipated that, following the tender offer, Messrs.
Bennett and Hurtt will serve as two of the three directors on the COMSAT Board
of Directors which Lockheed Martin will be entitled to designate under the
shareholders agreement.
 
Requirements for Nominations and Shareholder Proposals
 
 Generally.
 
   COMSAT's bylaws require that you provide advance notice of director
nominations or proposals which you would like to have brought before an annual
meeting of shareholders. COMSAT's general rule is that you must deliver certain
information concerning yourself and any director nomination or shareholder
proposal to COMSAT within a certain time period. This period runs at least 60
and not more than 90 days prior to the date that is the anniversary date of the
immediately preceding annual meeting of shareholders.
 
   If the annual meeting is scheduled to be held on a date that is more than 30
days before or after the anniversary date, COMSAT's bylaws provide a different
rule. In that case, COMSAT is required to mail out a notice of the date of the
annual meeting or to make public disclosure of the date of the annual meeting.
On the date that COMSAT either mails the notice or makes the public disclosure,
whichever comes first, a new period for submitting director nominations or
shareholder proposals opens. This period closes at the close of business on the
10th day in the period.
 
 This Year.
 
   This year the anniversary date is May 15, 1999. The annual meeting is
scheduled to be held on June 18, 1999, which is more than 30 days after the
anniversary date. On February 22, 1999, COMSAT issued a press release
announcing, among other things, the date of the annual meeting. Nominations by
you for director and proposals by you were required to be received no later
than March 3, 1999 to be considered at the annual meeting. This year the only
nomination or proposal received by the deadline is the proposal discussed under
the caption "Item 4. Shareholder Proposal." Consequently, no nomination and no
other proposal will be in order at the annual meeting.
 
 Other Requirements.
 
   COMSAT requires each director nominee to file with COMSAT's Corporate
Secretary a statement of his interests in communications common carriers in
such reasonable detail as the COMSAT Board of Directors may require. The
Corporate Secretary will provide you with a form of such statement upon written
request. You may also send a written request to the Corporate Secretary to
receive a list of persons whose nominations have been duly proposed in
accordance with COMSAT's bylaws and not withdrawn. This list and the statements
of interests filed by each director nominee may be inspected by any
shareholder. You may inspect these documents:
 
 
                                       80
<PAGE>
 
     (1) at the office of the Corporate Secretary, 6560 Rock Spring Drive,
  Bethesda, Maryland 20817 during normal business hours from the date of this
  proxy statement/prospectus until the date of the annual meeting, and
 
     (2) at the place of the annual meeting during the meeting.
 
Nominees for Election as 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 COMSAT 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.
 
                                        [PHOTO OF BETTY C. ALEWINE APPEARS HERE]
 
MARCUS C. BENNETT, 63, is a director of various
organizations. He was Executive Vice President and Chief
Financial Officer of Lockheed Martin from 1995 to January
1999 and is a director of Lockheed Martin. 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.
 
 
                                       [PHOTO OF MARCUS C. BENNETT APPEARS HERE]
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
Chairperson 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.
 
 
                                      [PHOTO OF LUCY WILSON BENSON APPEARS HERE]
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.
 
                                        [PHOTO OF EDWIN I. COLODNY APPEARS HERE]
 
                                       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.
 
                                 [PHOTO OF LAWRENCE S. EAGLEBURGER APPEARS HERE]
 
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.
 
                                         [PHOTO OF NEAL B. FREEMAN APPEARS HERE]
 
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 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.
 
                                          [PHOTO OF CALEB B. HURTT APPEARS HERE]
 
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.
 
                                         [PHOTO OF PETER W. LIKINS APPEARS HERE]
 
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.
 
                                       [PHOTO OF LARRY G. SCHAFRAN APPEARS HERE]
 
                                       82
<PAGE>
 
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.
 
                                      [PHOTO OF ROBERT G. SCHWARTZ APPEARS HERE]
 
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.
 
                                       [PHOTO OF KATHRYN C. TURNER APPEARS HERE]
 
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.
 
                                     [PHOTO OF GUY P. WYSER-PRATTE APPEARS HERE]
 
 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 this annual meeting.
 
                                         [PHOTO OF PETER S. KNIGHT APPEARS HERE]
 
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.
 
                                       [PHOTO OF CHARLES T. MANATT APPEARS HERE]
 
                                       83
<PAGE>
 
   The third Presidentially-appointed director position is currently vacant
pending nomination and confirmation of a successor.
 
   Your Board of Directors recommends that you vote in favor of the 12 director
nominees. Proxies solicited by the management will be so voted unless you
specify a contrary choice in your proxy. For approval, the proposal requires
the affirmative vote of a plurality of the votes represented at the annual
meeting.
 
Committees of the COMSAT Board of Directors
 
   The Board of Directors currently has six standing committees, described
below.
 
 Committee on Audit, Corporate Responsibilities and Ethics.
 
   The Committee on Audit, Corporate Responsibility and Ethics consists of Lucy
Wilson Benson (Chairperson), Marcus C. Bennett, Lawrence S. Eagleburger, Peter
W. Likins, Charles T. Manatt and Guy P. Wyser-Pratte. The committee met three
times during 1998. The committee is responsible for:
 
  .  making recommendations to the Board of Directors concerning the
     selection of independent public accountants;
 
  .  reviewing with the independent accountants the scope of their audit;
 
  .  reviewing the financial statements with the independent accountants;
 
  .  reviewing with the independent accountants and COMSAT's management and
     internal auditors COMSAT's accounting and audit practices and
     procedures, its internal controls and its compliance with laws and
     regulations; and
 
  .  reviewing COMSAT's policies regarding community and governmental
     relations, conflicts of interest, business conduct, ethics and other
     social, political and public matters, and the administration of these
     policies.
 
 Committee on Compensation and Management Development.
 
   The Committee on Compensation and Management Development consists of Caleb
B. Hurtt (Chairman), Neal B. Freeman, Peter S. Knight, Robert G. Schwartz and
Kathryn C. Turner. The committee met ten times during 1998. The committee is
responsible for:
 
  .  approving long-term compensation for senior executives;
 
  .  considering and making recommendations to the Board of Directors with
     respect to programs for human resources development and management
     organization and succession;
 
  .  recommending salary and bonus awards for senior executives;
 
  .  reviewing compensation policies and employee benefit and incentive
     plans; and
 
  .  exercising authority granted to it to administer these plans.
 
 Finance Committee.
 
   The Finance Committee consists of Robert G. Schwartz (Chairman), Betty C.
Alewine, Marcus C. Bennett, Neal B. Freeman, Peter S. Knight and Larry G.
Schafran. The committee met seven times during 1998. The committee is
responsible for:
 
  .  considering and making recommendations to the Board of Directors with
     respect to the financial affairs of COMSAT, including matters relating
     to capital structure and requirements, financial performance, dividend
     policy, capital and expense budgets and significant capital commitments;
     and
 
 
                                       84
<PAGE>
 
  .  other matters as may be referred to it by the Board of Directors, the
     Chairman of the Board or the Chief Executive Officer.
 
 Nominating and Corporate Governance Committee.
 
   The Nominating and Corporate Governance Committee consists of Edwin I.
Colodny (Chairman), Lucy Wilson Benson, Caleb B. Hurtt, Charles T. Manatt and
Robert G. Schwartz. The committee met three times during 1998. The committee is
responsible for:
 
  .  recommending to the Board of Directors qualified candidates for election
     as directors and as Chairman of the Board;
 
  .  considering, acting upon or making recommendations to the Board of
     Directors with respect to other matters as may be referred to it by the
     Board of Directors, the Chairman of the Board or the Chief Executive
     Officer; and
 
  .  considering candidates recommended by shareholders, if the
     recommendations are submitted in writing to the Secretary of COMSAT.
 
 Committee on Research and International Matters.
 
   The Committee on Research and International Matters consists of Peter W.
Likins (Chairman), Lucy Wilson Benson, Lawrence S. Eagleburger, Charles T.
Manatt, Larry G. Schafran and Kathryn C. Turner. The committee met two times
during 1998. The committee is responsible for:
 
  .  considering and making recommendations to the Board of Directors with
     respect to the research and development programs of COMSAT and the
     relationship of these programs to the business of COMSAT;
 
  .  matters relating to COMSAT's responsibilities and activities under the
     Satellite Act and the relationships of COMSAT with international
     organizations like INTELSAT and Inmarsat or with foreign governments or
     entities; and
 
  .  other matters as may be referred to it by the Board of Directors, the
     Chairman of the Board or the Chief Executive Officer.
 
 Strategic Planning Committee.
 
   The Strategic Planning Committee consists of Edwin I. Colodny (Chairman),
Robert G. Schwartz and Guy P. Wyser-Pratte. The committee met fourteen times
during 1998. The committee is responsible for:
 
  .  reviewing and making recommendations to the Board of Directors with
     respect to all aspects of COMSAT's business and its current and future
     business and financial strategies, transactional opportunities and the
     enhancement of shareholder value.
 
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 of Directors
after the annual meeting of shareholders. Those directors also receive a fee of
$1,000 per meeting for attending meetings of the Board of Directors, meetings
of committees of the Board of Directors or meetings held pursuant to a special
assignment. For service as chair of a committee of the Board of Directors, 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."
 
 
                                       85
<PAGE>
 
   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. Phantom stock units are held in an account for each director
pending retirement or termination of service on the Board of Directors. Upon
payment of a dividend on COMSAT common stock, an equivalent dollar amount is
converted to phantom stock units, based on the fair market value of the stock
on the dividend payment date, and credited to the director's account. The
phantom stock units increase or decrease in value based on an equivalent number
of shares of COMSAT 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 common stock equal to the number of phantom stock units credited to the
director's phantom stock unit 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
 
  .  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 this
     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 of Directors. 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.
 
 
                                       86
<PAGE>
 
   In 1991, each director at that time serving on the Board of Directors and
participating in the plan was given an election to receive his 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 these 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 this director if this beneficiary is then receiving the 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 account in
accordance with the terms of the plan and the participant's elections.
 
 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 service on the Board
     of Directors until the benefit reaches $200,000;
 
  .  payments increased by 5.5% for each additional year of service on the
     Board of Directors to age 72 (this increased coverage does not apply to
     Presidentially-appointed directors); and
 
  .  coverage continues after retirement from the Board of Directors.
 
   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. 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 1998 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.
 
                                       87
<PAGE>
 
   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.
 
   Options become fully exercisable and continue in force for the duration of
their terms in the following situations:
 
  .  termination of service on the Board of Directors by reason of retirement
     at age 72;
 
  .  expiration of a term as a Presidentially-appointed director;
 
  .  failure to stand for election with the Board of Directors' consent; or
 
  .  resignation with the Board of Directors' 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 of Directors,
     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 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.
 
   In September 1998, the plan was amended to provide that only the closing of
the merger with Lockheed Martin, 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, which is the market
value on exercise date less exercise price, of $52,130; $29,810; $47,325; and
$27,950, respectively.
 
 
                                       88
<PAGE>
 
 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.
 
Compensation Committee Interlocks, Insider Participation and Related Party
Transactions
 
   The following directors of COMSAT, who are also members of the Compensation
Committee of the Board of Directors, may be considered to have a relationship
with Lockheed Martin that may constitute an indirect material interest in the
proposed merger between COMSAT and Lockheed Martin.
 
   Standard Technology, Inc., a technology, engineering and systems integration
firm, has provided services to Lockheed Martin under various contracts, which
resulted from arm'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 April 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 of Wunder Knight, has rendered services to Lockheed
Martin pursuant to such engagement. Lockheed Martin paid Wunder Knight
$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 COMSAT since May 1996 and a director of
Lockheed Martin, has beneficial ownership of 5,672 shares of Lockheed Martin
common stock as of April 1, 1999. Mr. Hurtt also has an account in a Lockheed
Martin deferred compensation plan credited with 1,013 Lockheed Martin phantom
stock units.
 
              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 COMSAT's executive compensation philosophy. Set forth below is
the committee's report on the 1998 compensation of the executive officers of
COMSAT, including Mrs. Alewine, the Chief Executive Officer, and the other
executive officers named in the Summary Compensation Table (the "named
executive officers").
 
   COMSAT's executive compensation philosophy is designed to attract, motivate
and retain talented executives critical to the long-term success of COMSAT. One
of the objectives of this philosophy is to align
 
                                       89
<PAGE>
 
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 COMSAT's Annual
Incentive Plan, and long-term compensation, consisting of stock-based
incentives. The committee reviews and recommends to the Board of Directors 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 COMSAT'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 of Directors 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 COMSAT's financial
results, Mrs. Alewine's success in meeting personal objectives for 1998 which
she presented to the committee and COMSAT's achievement of strategic
objectives. These strategic objectives included the merger agreement with
Lockheed Martin, deregulation of COMSAT's largest business unit, completion of
the restructuring commenced in 1997 with the sale of COMSAT's manufacturing
unit, avoidance of adverse proposed legislation in the 105th Congress, and
rapid progress in the privatizations of INTELSAT and Inmarsat, the two global
satellite consortia in which COMSAT 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 of Directors approved, payment of a 1998 cash bonus
award of $400,000 for Mrs. Alewine.
 
   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 COMSAT, which
expires on August 1, 1999.
 
Long-Term Compensation
 
   Long-term compensation is an integral element of COMSAT's executive
compensation philosophy because the committee believes that stock ownership by
senior management and stock-based performance compensation arrangements enhance
shareholder value. COMSAT's long-term compensation strategy includes a blend of
stock compensation. For 1998, awards by the committee consisted of non-
qualified stock options and
 
                                       90
<PAGE>
 
restricted stock awards. These awards were consistent with ranges in the
revenue group of competitive companies approved by the committee. The stock
option ranges position COMSAT 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, including 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.
 
   Restricted stock awards 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 restricted stock awards 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 restricted stock awards 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 restricted stock awards in February
1998. The other named executive officers also received restricted stock awards
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 restricted stock awards are
intended to ensure the Federal tax deductibility under Section 162(m) of the
Internal Revenue Code of compensation paid to COMSAT's executive officers
pursuant to restricted stock awards. COMSAT 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
 
                                       91
<PAGE>
 
                             EXECUTIVE COMPENSATION
 
   The following table shows the compensation for the three fiscal years ended
December 31, 1998 received by (a) the Chief Executive Officer; (b) the other
four most highly compensated executive officers of COMSAT who were serving at
year end 1998; and (c) 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 the 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
                         -------------------------------------- --------------------------
                                                                Restricted    Securities
       Name and                                  Other Annual      Stock      Underlying      All Other
  Principal Position     Year  Salary  Bonus(1) Compensation(2) Award(s)(3) Options (#)(4) Compensation(5)
- -----------------------  ---- -------- -------- --------------- ----------- -------------- --------------- ---
<S>                      <C>  <C>      <C>      <C>             <C>         <C>            <C>             <C>
Betty C. Alewine, .....  1998 $533,173 $406,258     $   665      $182,625       30,000         $22,736
 President and Chief     1997  472,116  306,756       8,370       498,749            0          22,135
 Executive Officer       1996  355,846  189,111       3,238       238,188      260,442          20,799
 
Allen E. Flower, ......  1998  251,516  211,248         580       121,750       25,000          33,318
 Vice President and
  Chief                  1997  209,770   83,627       5,622       174,554       49,608          36,855
 Financial Officer       1996  180,000   73,301      60,122        90,000       43,407          31,578
 
Dwight E. Jasmann, ....  1998  252,000  142,396          44             0            0           9,887
 President and General   1997  244,985  204,187      39,961             0       18,603           4,750
 Manager, COMSAT         1996   98,770  203,600      13,795        97,813       12,402             923
 International(6)
 
John H. Mattingly, ....  1998  270,539  173,146           0        91,313       20,000           4,800
 President, COMSAT       1997  190,308   75,029           0        74,820       24,804           4,750
 Satellite Services      1996  162,039   57,274           0        35,994       12,402           4,498
 
Benjamin A. Pontano, ..  1998  197,667   60,000           0        60,875       15,000           5,545
 President, COMSAT       1997  153,663   50,000           0        49,867       18,603           4,610
 Laboratories            1996  130,000   42,600           0             0        3,721           3,900
 
Warren Y. Zeger, ......  1998  286,836  220,997         521       121,750       25,000          27,419
 Vice President,         1997  229,808   94,348       5,466       174,554       49,608          26,938
 General Counsel         1996  196,551  181,487       2,422        63,000       37,206          25,871
 and Secretary
</TABLE>
- --------
(1) Bonus for 1998 for each named executive officer, as indicated below,
    includes unused credits under COMSAT'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>
       Name                                                       Unused Credits
       ----                                                       --------------
       <S>                                                        <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>
 
                                       92
<PAGE>
 
(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 (a) $50,000 or (b) 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, restricted stock units and phantom stock
    units. Dividends are paid on restricted stock awards. Dividend equivalents
    are paid on restricted stock units and phantom stock units. 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>
                                 Number of Restricted Stock
                                  Awards/Restricted Stock
     Name                        Units/Phantom Stock Units  Value as of 12/31/98
     ----                        -------------------------- --------------------
     <S>                         <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. Instead of receiving a distribution
   of Ascent stock, all outstanding restricted stock awards, restricted stock
   units, and phantom stock units 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: (a)
    contributions by COMSAT to COMSAT's 401(k) Plan on behalf of the named
    executive officers; (b) above-market interest accrued for the named
    executive officers under COMSAT's Deferred Compensation Plan; and (c) life
    insurance premiums for the named executive officers. The life insurance
    premiums shown for the named executive officers represent split dollar
    premiums which include (a) the value of the premiums paid by COMSAT 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 (b) the value of the benefit to each named
    executive officer of the remainder of the premiums paid by COMSAT,
    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 COMSAT.
 
<TABLE>
<CAPTION>
                                                          Above-
                                            401(k) Plan   Market  Life Insurance
                     Name                  Contributions Interest    Premiums
                     ----                  ------------- -------- --------------
     <S>                                   <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 COMSAT as President
    and General Manager, COMSAT International in August 1996. He resigned in
    February 1998.
 
                                       93
<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
                             Securities     Options Granted
                         Underlying Options to Employees in   Exercise   Expiration    Grant Date
Name                       Granted (#)(1)   Fiscal Year(2)  Price ($/Sh)    Date    Present Value(3)
- ----                     ------------------ --------------- ------------ ---------- ----------------
<S>                      <C>                <C>             <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 COMSAT
    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) COMSAT 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 0.3642; 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>
                                                                                               Value of Unexercised In-
                            Shares                  Number of Securities Underlying                      The-
                          Underlying              Unexercised Options at 12/31/98 (1)          Money Options at 12/31/98
                            Options      Value    ----------------------------------------     -------------------------
Name                     Exercised (#)  Realized  Exercisable (#)       Unexercisable (#)      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.
 
Pension Plans
 
   The following table shows the estimated annual benefits payable upon
retirement under COMSAT'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.
 
 
                                       94
<PAGE>
 
        Estimated Annual Benefits -- COMSAT Corporation Retirement Plan
 
<TABLE>
<CAPTION>
                  Average                           Years of Service
                  Annual                 ---------------------------------------
                Salary ($)                 15      20      25      30      35
                ----------               ------- ------- ------- ------- -------
   <S>                                   <C>     <C>     <C>     <C>     <C>
   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%, or 70% for the Chief Executive Officer, of the
participant's average annual compensation, consisting of 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 of Directors must consent to such 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."
 
                                       95
<PAGE>
 
   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 by COMSAT other than for cause or disability, or by the
participant for good reason, then, instead of any other severance payments or
severance benefits payable to the participant by COMSAT, the participant will
be entitled to receive the following during the benefits continuation period,
as defined below:
 
  .  base salary;
 
  .  targeted annual bonus under COMSAT's Annual Incentive Plan; and
 
  .  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. If, however, the amount of the payment that the participant is
entitled to receive upon a termination of employment under the Retention Bonus
Plan, as described below, is greater than the aggregate amount that the
participant is entitled to receive under the amended severance plan, exclusive
of health and welfare benefits, then the participant will forfeit all rights to
receive these payments under the amended severance plan.
 
   The amended severance plan also provides that, in the event of a
participant's termination of employment under the circumstances described
above, such participant would be entitled to receive a gross-up payment if
 
                                       96
<PAGE>
 
any payment or benefit to such participant would constitute an excess parachute
payment under Section 280G of the Internal Revenue Code.
 
Retention Bonus Plan
 
   On September 18, 1998, COMSAT adopted the Retention Bonus Plan. The
Retention Bonus Plan generally provides retention bonuses to key employees who
remain employed by COMSAT, or whose employment is terminated under specific
circumstances, through specified dates following the signing of the merger
agreement. The Retention Bonus Plan covers approximately 108 participants, who
are classified as 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 participant'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 Participant elects to terminate his or
her employment for good reason, such Group I Participant 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 termination of employment under the
Retention Bonus Plan, such participant will not be entitled to any severance
payment under any severance 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 as
of July 19, 1996, and amended as of May 16, 1997 and July 18, 1997, and has
entered into employment agreements with Mr. Flower and Mr. Zeger dated as of
April 18, 1997, and amended as of July 18, 1997. On September 18, 1998, COMSAT
amended the employment agreements in connection with the merger.
 
                                       97
<PAGE>
 
   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 of Directors;
 
  .  eligibility for an annual bonus based on performance measures determined
     by the Board of Directors' 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 the following for a period of time as specified below:
 
    (1) his or her then current base salary;
 
    (2) 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
 
    (3) 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.
 
  .  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 of Directors' discretion to waive such reduction;
 
  .  if Mr. Flower's employment is not renewed after April 17, 2002, Mr.
     Flower will be entitled to receive:
 
    (1) the benefits described above for one year thereafter, and
 
    (2) 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 of Directors' 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 of Directors' 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.
 
   Pursuant to her employment agreement, Mrs. Alewine was granted, on October
17, 1996, 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; on October 17, 1996, 6,201 restricted stock units which vest
after three years; and on February 20, 1997, 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.
 
                                       98
<PAGE>
 
   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 Directors of COMSAT such
     that the incumbent directors elected as of May 17, 1996 cease to
     constitute a majority of the Board of Directors; 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;
 
  .  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
of Directors 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 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 of Directors or COMSAT's shareholders of the merger or
the merger agreement, the commencement or the closing of the tender offer, or
the acquisition by Lockheed Martin or Regulus of COMSAT Government Systems.
 
   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 completion of the merger,
 
    (b) the termination date of the merger pursuant to the merger
        agreement, or
 
    (c) September 18, 2000,
 
    equal to 150% of the sum of the executive's highest base salary plus
    the executive's highest 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 highest
     base salary plus the executive's highest 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,
instead 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 of a post-closing severance payment
     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 by COMSAT other than for cause or disability, or by the executive for good
reason, then, instead 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 executives 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
 
  (a) 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 employment within 30 days following the
      closing of the merger and the executive's employment is terminated
      within the 30-day period, or
 
  (b) 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.
 
                                      100
<PAGE>
 
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 of Directors; and
 
  .  guaranteed bonus of $130,000 for 1996 and annual bonuses thereafter
     based on performance measures determined by the Board of Directors'
     Compensation Committee with a target bonus equal to 40% of Mr. Jasmann's
     base salary.
 
   On August 1, 1996, Mr. Jasmann was granted:
 
  .  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
 
  .  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.
 
                         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
of Directors 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, restricted stock awards, restricted
     stock units and phantom stock units 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
 
                                      101
<PAGE>
 
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 of Directors 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 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, and not any of the
other transactions contemplated by the merger agreement, will constitute a
change in control of COMSAT.
 
                               PERFORMANCE GRAPH
 
   The following graph compares the cumulative total shareholder return for
COMSAT's common stock with the cumulative total return of the S&P 500 Stock
Index and a Peer Group Index constructed by COMSAT 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 use WorldCom, Inc.
data for all years and include MCI Corporation data for 1998.
 
 
 
 
 
                        [PERFORMANCE CHART APPEARS HERE]
 
                                      102
<PAGE>
 
             ITEM 3. APPOINTMENT OF INDEPENDENT PUBLIC ACCOUNTANTS
 
   You will vote at the annual meeting to appoint independent public
accountants to audit and certify to you the financial statements of COMSAT for
the fiscal year ending December 31, 1999. Your Board of Directors has
recommended the appointment of Deloitte & Touche LLP as such independent public
accountants. Deloitte & Touche LLP acted in such capacity for fiscal year 1998.
Representatives of Deloitte & Touche LLP will be present at the annual meeting
to respond to appropriate questions and to make a statement if they desire to
do so.
 
   Your Board of Directors recommends that you vote for the appointment of
Deloitte & Touche LLP as independent public accountants. Proxies solicited by
the management will be so voted unless you specify a contrary choice in your
proxy. For approval, the proposal requires the affirmative vote of a majority
of the shares represented and entitled to vote at the annual meeting.
 
                   ITEM 4. ACTION UPON A SHAREHOLDER PROPOSAL
   Mrs. Evelyn Y. Davis, Watergate Office Building, 2600 Virginia Avenue, N.W.,
Suite 215, Washington, D.C. 20037, owner of 200 shares of COMSAT common stock,
has given notice that she will introduce the following resolution at the annual
meeting:
 
   RESOLVED: "That the shareholders of COMSAT assembled in Annual Meeting in
person and by proxy, hereby recommend that COMSAT affirm its political non-
partisanship. To this end the following practices are to be avoided:
 
  (a) The handing of contribution cards of a single political party to an
      employee by a supervisor.
 
  (b) Requesting an employee to send a political contribution to an
      individual in COMSAT for a subsequent delivery as part of a group of
      contributions to a political party or fund raising committee.
 
  (c) Requesting an employee to issue personal checks blank as to payee for
      subsequent forwarding to a political party, committee or candidate.
 
  (d) Using supervisory meetings to announce that contribution cards of one
      party are available and that anyone desiring cards of a different party
      will be supplied one on request to his supervisor.
 
  (e) Placing a preponderance of contribution cards of one party at mail
      station locations.
 
   And if COMSAT engages in none of the above, to disclose this to ALL
shareholders in each quarterly report.
 
   REASONS: "COMSAT must deal with a great number of governmental units,
commissions and agencies. It should maintain scrupulous political neutrality to
avoid embarrassing entanglements detrimental to its business. Above all, it
must avoid the appearance of coercion in encouraging its employees to make
political contributions against their personal inclinations. The Troy (Ohio)
News has condemned partisan solicitation for political purposes by managers in
a local company (not COMSAT)."
 
   Last year the owners of 5,711,532 shares, representing approximately 17.5%
of shares voting, voted FOR this proposal."
 
   "If you AGREE, please mark your proxy FOR this resolution."
 
   Your Board of Directors Opposes this Proposal.
 
   COMSAT has a strong record of supporting the political process in a
bipartisan manner. To the knowledge of the directors and management of COMSAT,
the types of practices described in the proposal as "to be avoided" have not
occurred at COMSAT. COMSAT has directors who have served as political
appointees of both Democratic and Republican administrations, which promotes a
corporate culture of bi-partisanship.
 
                                      103
<PAGE>
 
   The COMSAT Political Action Committee, which is funded by voluntary
contributions from employees, contributes to candidates of both of the two
major political parties. Employees are not required to contribute to the COMSAT
Political Action Committee. The COMSAT Political Action Committee solicits
contributions periodically, and informs employees that all contributions are
entirely voluntary.
 
   In light of COMSAT's past history of bi-partisanship, the COMSAT Board of
Directors believes that the resolution is unnecessary. If passed, the
resolution would create an administrative quarterly reporting burden without
resulting in any real benefit to you. Other companies, including COMSAT's
competitors, would not be subject to similar reporting requirements and the
related compliance burden and associated costs. For those reasons, COMSAT
recommends that you vote "no."
 
   Your Board of Directors recommends that you vote against this proposal.
Proxies solicited by the management will be so voted unless you specify a
contrary choice in your proxy. For approval, the proposal requires the
affirmative vote of a majority of the shares represented and entitled to be
voted at the annual meeting.
 
                                 OTHER MATTERS
 
   As of April 30, 1999, COMSAT management knew of no other matters to be
presented for action at the annual meeting. If any other matter is properly
introduced by COMSAT, the persons named in the accompanying form of proxy will
vote the shares represented by the proxies according to their judgment. In
accordance with COMSAT's bylaws, proposals by shareholders were required to be
received no later than March 3, 1999 to be considered at the annual meeting.
See "Item 2. Election of Directors--Requirements for Nominations and
Shareholder Proposals." No other proposals were received other than the one
discussed under the caption "Item 4. Action Upon a Shareholder Proposal."
 
   Unless the merger is completed before this date, COMSAT contemplates that
the 2000 Annual Meeting of Shareholders will be held on or about May 19, 2000.
If you wish to submit a proposal to be included in the proxy statement for
consideration at the 2000 Annual Meeting of Shareholders should submit them in
writing to the Corporate Secretary, COMSAT Corporation, 6560 Rock Spring Drive,
Bethesda, Maryland 20817, to be received no later than January 15, 2000.
 
                                 LEGAL MATTERS
 
   The validity of the Lockheed Martin common stock to be issued in connection
with the merger will be passed upon by King & Spalding, Washington, D.C. King &
Spalding, Washington, D.C., special tax counsel to Lockheed Martin, and
Skadden, Arps, Slate, Meagher & Flom LLP, Washington, D.C., special tax counsel
to COMSAT, have passed and will pass on the material federal income tax
consequences of the merger.
 
                                    EXPERTS
 
   Ernst & Young LLP, independent auditors, have audited the consolidated
financial statements of Lockheed Martin as of December 31, 1998 and 1997 and
for each of the three years in the period ended December 31, 1998, incorporated
by reference in this proxy statement/prospectus, as set forth in their report,
which is also incorporated in this proxy statement/prospectus by reference.
Such consolidated financial statements of Lockheed Martin are incorporated by
reference in reliance on their report, given on their authority as experts in
accounting and auditing.
 
   The financial statements incorporated in this proxy statement/prospectus by
reference from COMSAT's Annual Report on Form 10-K for the fiscal year ended
December 31, 1998 have been audited by Deloitte &
 
                                      104
<PAGE>
 
Touche LLP, independent auditors, as stated in their report, which is also
incorporated in this proxy statement/prospectus by reference, and have been so
incorporated in reliance upon the report of such firm given upon their
authority as experts in accounting and auditing.
 
                      WHERE YOU CAN FIND MORE INFORMATION
 
   Lockheed Martin and COMSAT file annual, quarterly and special reports, proxy
statements and other information with the SEC. You may read and copy any
documents filed with the SEC by either company at the public reference
facilities maintained by the SEC in Washington, D.C., New York, New York and
Chicago Illinois. Please call the SEC at 1-800-SEC-0330 for further information
on the SEC's public reference rooms. Lockheed Martin's and COMSAT's filings are
also available to the public from the SEC's website at http://www.sec.gov. Each
company also has its filings on its website. COMSAT's website is
http://www.comsat.com, and Lockheed Martin's website is
http://www.lockheedmartin.com. In addition, Lockheed Martin's and COMSAT's
filings with the SEC may be inspected at the offices of the New York Stock
Exchange, 20 Broad Street, New York, New York 10005.
 
   Lockheed Martin filed a Registration Statement on Form S-4 to register with
the SEC the Lockheed Martin common stock to be issued in the merger. This proxy
statement/prospectus is a part of that Registration Statement and constitutes a
prospectus of Lockheed Martin in addition to being a proxy statement of COMSAT
for the annual meeting. As allowed by SEC rules, this proxy
statement/prospectus does not contain all the information you can find in the
Registration Statement or the exhibits to the Registration Statement.
 
   The SEC allows COMSAT (File No. 1-3229) and Lockheed Martin (File No. 1-
11437) to incorporate by reference information in this proxy
statement/prospectus, which means important information may be disclosed to you
by referring you to another document filed separately with the SEC. This proxy
statement/prospectus incorporates by reference the following documents:
 
  .  Lockheed Martin's Annual Report on Form 10-K for the fiscal year ended
     December 31, 1998;
 
  .  Lockheed Martin's Current Reports on Form 8-K dated January 19, 1999,
     January 28, 1999, February 10, 1999, February 16, 1999 and April 21,
     1999;
 
  .  Lockheed Martin's Schedule 14D-1 dated September 25, 1998, as amended on
     October 13, 1998, November 18, 1998, December 18, 1998, January 7, 1999,
     January 25, 1999, February 9, 1999, February 25, 1999 and April 21,
     1999;
 
  .  The description of Lockheed Martin's Common Stock contained under the
     caption "Description of Lockheed Martin Capital Stock" set forth in
     Lockheed Martin's Joint Proxy Statement/Prospectus dated February 9,
     1995 constituting part of Lockheed Martin's Registration Statement on
     Form S-4 (Reg. No. 33-57645);
 
  .  COMSAT's Annual Report on Form 10-K for the fiscal year ended December
     31, 1998;
 
  .  COMSAT's Current Report on Form 8-K dated February 22, 1999; and
 
  .  COMSAT's Schedule 14D-9 dated September 25, 1998, as amended on February
     9, 1999, March 1, 1999 and April 22, 1999.
 
   The information incorporated by reference is part of this proxy
statement/prospectus, except for any information superseded by information in,
or incorporated by reference in, this proxy statement/prospectus. All documents
filed by Lockheed Martin or COMSAT under Sections 13(a), 13(c), 14 or 15(d) of
the Exchange Act after the date of this proxy statement/prospectus and before
the annual meeting will be incorporated by reference in this proxy
statement/prospectus from the date such documents are filed.
 
   Any statement contained in a document incorporated by reference in this
proxy statement/prospectus will be modified or superseded to the extent that a
statement contained in this proxy statement/prospectus, or in any
 
                                      105
<PAGE>
 
other subsequently filed document, modifies or supersedes such previous
statement. Any statement modified or superseded will not be a part of this
proxy statement/prospectus except as modified or superseded.
 
   All information contained or incorporated by reference in this proxy
statement/prospectus relating to Lockheed Martin has been supplied by Lockheed
Martin. All information relating to COMSAT has been supplied by COMSAT.
 
   Documents incorporated by reference, other than exhibits to these documents
not specifically incorporated by reference into this proxy
statement/prospectus, are available without charge, upon written or oral
request by any person to whom this proxy statement/prospectus has been
delivered, from Investor Relations, COMSAT, 6560 Rock Spring Drive, Bethesda,
Maryland 20817 (toll-free telephone: 888-233-5777) or from Investor Relations,
Lockheed Martin, 6801 Rockledge Drive, Bethesda, Maryland 20817 (telephone:
301-897-6000). Any exhibit will be provided upon payment of the reasonable cost
of providing such exhibit. To ensure timely delivery of the documents, your
request should be made by June 11, 1999.
 
   No person has been authorized to give any information or make any
representation other than those contained or incorporated by reference in this
proxy statement/prospectus, and, if given or made, such information or
representation must not be relied upon as having been authorized. This proxy
statement/prospectus does not constitute an offer to sell or a solicitation of
an offer to buy the securities covered by this proxy statement/prospectus or a
solicitation of a proxy in any jurisdiction where, or to or from any person to
whom, it is unlawful to make such offer, solicitation of an offer or proxy
solicitation. Neither the delivery of this proxy statement/prospectus nor any
distribution of securities made hereunder will, under any circumstances, create
any implication that there has been no change in the affairs of Lockheed Martin
or COMSAT since the date hereof or that the information contained or
incorporated by reference in this proxy statement/prospectus is correct as of
any time subsequent to its date.
 
                                      106
<PAGE>
 
                       DIRECTIONS TO THE COMSAT BUILDING
                   6560 ROCK SPRING DRIVE--BETHESDA, MARYLAND
 
   The COMSAT Building at Rock Spring Plaza in Bethesda, Maryland, is located
on the corner of Rock Spring Drive and Fernwood Road. Shareholders who wish to
use public transportation may take the Red Line of the Washington Metro to the
Medical Center Station. Take the Metro Bus J2 (destination Montgomery Mall),
which stops at the first bus shelter at the top of the escalator, to the corner
of Fernwood Road and Rock Spring Drive. To return to the Medical Center
Station, you may take Metro Bus J2 (destination Silver Spring), which stops on
Fernwood Road on the Marriott side of the street.
 
   Set forth below is a map and instructions on how to get there by car. The
COMSAT garage will be open for shareholders' parking on the first level (P1).
 
 
 
 
 
            [MAP SHOWING DIRECTIONS TO COMSAT BUILDING APPEARS HERE]
 
From Frederick/I-270 South:
   Take I-270 East toward Silver Spring. Exit at Old Georgetown Road and turn
right. At the second light turn right on Democracy Boulevard. At the second
light turn right on Fernwood Road. Just beyond the first light turn right onto
the driveway that leads to the COMSAT garage entrance.
 
From Silver Spring/I-495 West:
 
   Take I-495 West to Exit 36 (Old Georgetown Road). Turn right on Old
Georgetown Road (toward Rockville). At third light turn left on Democracy
Boulevard. At second light turn right on Fernwood Road. Just beyond the first
light turn right onto the driveway that leads to the COMSAT garage entrance.
 
From Northern Virginia/I-495 North:
 
   Take I-495 North to I-270 Spur North. Take the first exit off of I-270 Spur
(Democracy Boulevard East). At first intersection light, which immediately
follows the light at the Fire Station, turn left on Fernwood Road. Just beyond
the first light turn right onto the driveway that leads to the COMSAT garage
entrance.
 
                                      107
<PAGE>
 
                                                                      APPENDIX I
 
 
 
                          AGREEMENT AND PLAN OF MERGER
 
                         DATED AS OF SEPTEMBER 18, 1998
 
                                     AMONG
 
                              COMSAT CORPORATION,
 
                          LOCKHEED MARTIN CORPORATION
 
                                      AND
 
                               DENEB CORPORATION
 
<PAGE>
 
                               TABLE OF CONTENTS
 
<TABLE>
<CAPTION>
                                                                           Page
                                                                           ----
 <C>          <S>                                                          <C>
                                 ARTICLE I
                                 The Offer
 Section 1.1  The Offer..................................................   I-1
 Section 1.2  COMSAT Actions.............................................   I-2
 Section 1.3  Shareholder Lists..........................................   I-3
                                ARTICLE II
                            Related Agreements
 Section 2.1  Registration Rights Agreement..............................   I-3
 Section 2.2  Shareholders Agreement.....................................   I-4
 Section 2.3  Carrier Acquisition Agreement..............................   I-4
                                ARTICLE III
                                The Merger
 Section 3.1  The Merger.................................................   I-4
 Section 3.2  Effective Time; Closing....................................   I-4
 Section 3.3  Effects of the Merger......................................   I-4
 Section 3.4  Certificate of Incorporation and By-Laws...................   I-5
 Section 3.5  Directors..................................................   I-5
 Section 3.6  Officers...................................................   I-5
 Section 3.7  Effect on Capital Stock....................................   I-5
 Section 3.8  Dissenting Shares..........................................   I-5
 Section 3.9  Exchange of Stock..........................................   I-6
 Section 3.10 No Fractional Shares of Lockheed Martin Common Stock.......   I-7
 Section 3.11 Termination of Exchange Fund...............................   I-7
 Section 3.12 No Liability...............................................   I-8
 Section 3.13 Lost Certificates..........................................   I-8
 Section 3.14 Certain Adjustments........................................   I-8
 Section 3.15 Conditions to Closing of Merger............................   I-8
                                ARTICLE IV
                 Representations and Warranties of COMSAT
 Section 4.1  Organization...............................................  I-10
 Section 4.2  Authority..................................................  I-11
 Section 4.3  Consents and Approvals; No Violations......................  I-11
 Section 4.4  Capitalization.............................................  I-12
 Section 4.5  Absence of Certain Changes.................................  I-13
 Section 4.6  Reports....................................................  I-13
 Section 4.7  No Default.................................................  I-14
 Section 4.8  Litigation; Compliance with Law............................  I-14
 Section 4.9  Employee Benefit Plans; ERISA..............................  I-14
 Section 4.10 Intellectual Property; Year 2000...........................  I-15
 Section 4.11 Certain Contracts and Arrangements.........................  I-16
 Section 4.12 Taxes......................................................  I-16
 Section 4.13 Governmental Authorizations................................  I-17
 Section 4.14 Environmental Matters......................................  I-18
 Section 4.15 Brokerage Fees and Commissions.............................  I-18
</TABLE>
 
                                      I-i
<PAGE>
 
<TABLE>
<CAPTION>
                                                                         Page
                                                                         ----
 <C>          <S>                                                        <C>
                                ARTICLE V
  Representations and Warranties of Lockheed Martin and Acquisition Sub
 Section 5.1  Organization.............................................  I-18
 Section 5.2  Authority................................................  I-18
 Section 5.3  Consents and Approvals; No Violations....................  I-19
 Section 5.4  Capitalization...........................................  I-19
 Section 5.5  Absence of Certain Changes...............................  I-20
 Section 5.6  Reports..................................................  I-20
 Section 5.7  Opinion of Financial Advisor.............................  I-20
 Section 5.8  Brokers..................................................  I-20
                               ARTICLE VI
                                Covenants
 Section 6.1  Conduct of Business of COMSAT............................  I-20
 Section 6.2  INTELSAT and Inmarsat Privatizations.....................  I-23
 Section 6.3  Conduct of Business of Lockheed Martin...................  I-24
 Section 6.4  No Solicitation..........................................  I-25
              Preparation of Proxy Statement; COMSAT Shareholders
 Section 6.5  Meeting..................................................  I-26
 Section 6.6  Access to Information....................................  I-27
 Section 6.7  Reasonable Efforts.......................................  I-27
 Section 6.8  Listing Application......................................  I-28
 Section 6.9  Consents and Approvals...................................  I-28
 Section 6.10 Public Announcements.....................................  I-29
 Section 6.11 Notification.............................................  I-29
 Section 6.12 Certain Litigation.......................................  I-30
 Section 6.13 Employee and Benefit Matters; Stock Options and Awards...  I-30
 Section 6.14 No Restrictions..........................................  I-31
 Section 6.15 Advice of Changes........................................  I-31
 Section 6.16 Indemnification..........................................  I-31
 Section 6.17 No Control...............................................  I-32
 Section 6.18 Accountant's Letters.....................................  I-32
 Section 6.19 North American Numbering Plan............................  I-32
 Section 6.20 Affiliate Letters........................................  I-32
                               ARTICLE VII
                     Termination; Amendment; Waiver
 Section 7.1  Termination..............................................  I-33
 Section 7.2  Effect of Termination....................................  I-34
 Section 7.3  Fees and Expenses........................................  I-34
 Section 7.4  Amendment................................................  I-35
 Section 7.5  Extension; Waiver........................................  I-35
                              ARTICLE VIII
                              Miscellaneous
 Section 8.1  Survival.................................................  I-35
 Section 8.2  Entire Agreement.........................................  I-35
 Section 8.3  Governing Law............................................  I-35
 Section 8.4  Notices..................................................  I-35
 Section 8.5  Successors and Assigns; No Third Party Beneficiaries.....  I-36
</TABLE>
 
                                      I-ii
<PAGE>
 
<TABLE>
<CAPTION>
                                                                           Page
                                                                           ----
 <C>          <S>                                                          <C>
 Section 8.6  Counterparts...............................................  I-36
 Section 8.7  Interpretation.............................................  I-36
 Section 8.8  Schedules..................................................  I-36
 Section 8.9  Legal Enforceability.......................................  I-37
 Section 8.10 No Waivers; Remedies; Specific Performance.................  I-37
 Section 8.11 Exclusive Jurisdiction.....................................  I-37
 Section 8.12 Waiver of Jury Trial.......................................  I-37
</TABLE>
 
                                    EXHIBITS
                                   --------
 
<TABLE>
<S>                       <C>
Exhibit A................ Conditions to Offer
Exhibit B................ Form of Registration Rights Amendment
Exhibit C................ Form of Shareholders Agreement
Exhibit D................ Form of Carrier Acquisition Agreement
Exhibit E................ Form of Amended and Restated Articles of Incorporation
Exhibit F................ Form of Tax Opinions
 
                                   SCHEDULES
                                  ----------
 
Schedule 1............... COMSAT Disclosure Schedule
</TABLE>
 
                                     I-iii
<PAGE>
 
                             TABLE OF DEFINED TERMS
 
<TABLE>
<CAPTION>
Term                                                           Section No.
- ----                                                           -----------
<S>                                                       <C>
Acquisition Proposal..................................... 6.4(a)
Acquisition Sub.......................................... Introductory Paragraph
Agreement................................................ Introductory Paragraph
Amendment................................................ 4.2
Antitrust Laws........................................... 6.9(c)
Assets................................................... 4.3
Audit.................................................... 4.12(j)(i)
Authorized Carrier Conditions............................ Exhibit A
Authorized Carriers...................................... 1.1(a)
Average Price............................................ 3.7(a)(i)
Carrier Acquisition...................................... 2.3
Carrier Acquisition Agreement............................ 2.3
CCEC..................................................... 6.9(c)
Certificates............................................. 3.9(b)
Closing.................................................. 3.2
Closing Date............................................. 3.2
Code..................................................... 3.15(c)(ii)
Communications Act....................................... 4.3
COMSAT................................................... Introductory Paragraph
COMSAT Affiliate Letter.................................. 6.20
COMSAT Business Plans.................................... 6.1(i)
COMSAT Carrier Subsidiary................................ 2.3
COMSAT Common Stock...................................... 1.1(a)
COMSAT Contracts......................................... 4.11(a)
COMSAT Disclosure Schedule............................... Article IV
COMSAT Employees......................................... 6.13(d)
COMSAT Form 10-K......................................... 4.5
COMSAT Preferred Stock................................... 4.4(a)
COMSAT Representatives................................... 6.4(a)
COMSAT SEC Documents..................................... 4.6
COMSAT Shareholders Meeting.............................. 6.5(b)
COMSAT Stock Options..................................... 4.4(a)
COMSAT Stock Plans....................................... 4.4(a)
Confidentiality Agreements............................... 8.2
DCBCA.................................................... 1.1(a)
DCRA..................................................... 3.2
DGCL..................................................... 3.1
Determination Date....................................... 3.7(a)(i)
Dissenting Shares........................................ 3.8
EC Merger Regulations.................................... 6.9(c)
Effective Time........................................... 3.2
Environmental Claims..................................... 4.14
Environmental Laws....................................... 4.14
Equity Securities........................................ 4.4(a)
ERISA.................................................... 4.9(a)
ERISA Affiliate.......................................... 4.9(a)
Exchange Act............................................. 1.1(a)
Exchange Agent........................................... 3.9(a)
Exchange Fund............................................ 3.9(a)
</TABLE>
 
                                      I-iv
<PAGE>
 
<TABLE>
<CAPTION>
Term                                                           Section No.
- ----                                                           -----------
<S>                                                       <C>
FCC...................................................... 3.15(a)(ii)
Form S-4................................................. 6.5(a)
Forward Merger........................................... 3.1
GAAP..................................................... 4.6
Governmental Authorizations.............................. 4.13
Governmental Authority................................... 3.11
HSR Act.................................................. 6.9(c)
ICO...................................................... 6.2(e)(i)
Indemnified Parties...................................... 6.16(a)
Inmarsat................................................. 3.9(b)
Inmarsat Convention...................................... 6.2(e)(ii)
Inmarsat Existing Documents.............................. 6.2(e)(iii)
Inmarsat Interests....................................... 6.2(e)(iv)
Inmarsat Investment Share................................ 6.2(e)(v)
Inmarsat Privatization................................... 6.2(e)(vi)
Inmarsat Restructuring Documents......................... 6.2(e)(vii)
Intellectual Property.................................... 4.10(a)
INTELSAT................................................. 3.9(b)
INTELSAT Agreement....................................... 6.2(e)(viii)
INTELSAT Existing Documents.............................. 6.2(e)(viii)
INTELSAT Operating Agreement............................. 6.2(e)(viii)
INTELSAT Interests....................................... 6.2(e)(ix)
INTELSAT Investment Share................................ 6.2(e)(x)
IRS...................................................... 4.9(a)
Laws..................................................... 4.1
Liabilities.............................................. 4.6
Lien..................................................... 4.3
Lockheed Martin.......................................... Introductory Paragraph
Lockheed Martin Common Stock............................. 3.7(a)
Lockheed Martin Form 10-K................................ 5.5
Lockheed Martin Preferred Stock.......................... 5.4(a)
Lockheed Martin SEC Documents............................ 5.6
Lockheed Martin Series Preferred Stock................... 5.4(a)
Lockheed Martin Stock Options............................ 5.4(a)
Lockheed Martin Stock Plans.............................. 5.4(a)
Lock-Up Agreement........................................ 6.2(c)
Material Adverse Effect.................................. 4.1
Maximum Amount........................................... 6.16(b)
Measurement Date......................................... Exhibit A
Merger................................................... 3.1
Merger Consideration..................................... 3.7(a)
Minimum Condition........................................ Exhibit A
NYSE..................................................... 3.2
Offer.................................................... 1.1(a)
Offer Closing Time....................................... 1.1(a)
Offer Documents.......................................... 1.1(d)
Offer Price.............................................. 1.1(a)
Offer Subsidiary......................................... 1.1(a)
Order.................................................... 6.9(d)
PBGC..................................................... 4.9(a)
Person................................................... 3.9(b)
</TABLE>
 
                                      I-v
<PAGE>
 
<TABLE>
<CAPTION>
Term                                                                Section No.
- ----                                                                -----------
<S>                                                                 <C>
Plans.............................................................. 4.9(a)
Proxy Statement/Prospectus......................................... 6.5(a)
Recent SEC Documents............................................... 4.8(b)
Registration Rights Agreement...................................... 2.1
Reverse Merger..................................................... 3.1
Satellite Act...................................................... 1.1(a)
Schedule 14D-9..................................................... 1.2(b)
SEC................................................................ 1.1(a)
Securities Act..................................................... 3.15(a)(v)
Shareholders Agreement............................................. 2.2
Shares............................................................. 1.1(a)
Significant Adverse Effect......................................... 3.15(b)
Significant Subsidiary............................................. 4.3
Stock Option Plans................................................. 4.4(a)
Stock Value........................................................ 3.15(c)(i)
Subsidiary......................................................... 4.2
Superior Proposal.................................................. 6.4(b)
Surviving Corporation.............................................. 3.1
Taxes.............................................................. 4.12(j)(ii)
Tax Returns........................................................ 4.12(j)(iii)
Termination Fee.................................................... 7.3(a)(ii)
Transaction Agreements............................................. 2.3
</TABLE>
 
                                      I-vi
<PAGE>
 
                          AGREEMENT AND PLAN OF MERGER
 
   AGREEMENT AND PLAN OF MERGER (this "Agreement") dated as of September 18,
1998 among LOCKHEED MARTIN CORPORATION, a Maryland corporation ("Lockheed
Martin"), DENEB CORPORATION, a Delaware corporation and a wholly-owned
subsidiary of Lockheed Martin ("Acquisition Sub"), and COMSAT CORPORATION, a
District of Columbia corporation ("COMSAT").
 
   In consideration of the representations, warranties, covenants and
agreements herein contained, and intending to be legally bound hereby, Lockheed
Martin, Acquisition Sub and COMSAT hereby agree as follows:
 
                                   ARTICLE I
 
                                   THE OFFER
 
  Section 1.1 The Offer.
 
   (a) Subject to this Agreement not having been terminated in accordance with
the provisions of Section 7.1 hereof, Lockheed Martin, acting through a wholly-
owned single member Delaware limited liability company (the "Offer
Subsidiary"), shall as promptly as practicable, but in no event later than five
business days from the date of the public announcement of the terms of this
Agreement, commence (within the meaning of Rule 14d-2 under the Securities
Exchange Act of 1934, as amended, and all rules and regulations promulgated
thereunder (the "Exchange Act")) an offer to purchase for cash (as it may be
amended in accordance with the terms of this Agreement, the "Offer") up to the
number of shares (collectively, the "Shares") of COMSAT's common stock, without
par value (the "COMSAT Common Stock"), that is equal to the remainder of
(i) 49% of the number of shares of COMSAT Common Stock outstanding at the close
of business on the date of purchase pursuant to the Offer minus (ii) the number
of shares of COMSAT Common Stock then owned of record by "authorized carriers"
(as defined in the Communications Satellite Act of 1962, as amended, 47 U.S.C.
(S)701 et. seq., and all rules and regulations promulgated thereunder (the
"Satellite Act")) ("Authorized Carriers"), as evidenced by issuance of shares
of Series II COMSAT Common Stock, minus (iii) the number of shares of COMSAT
Common Stock with respect to which written demand shall have been made and not
withdrawn under Section 29-373 of the District of Columbia Business Corporation
Act (the "DCBCA"), at a price of not less than $45.50 per Share, net to the
seller in cash (the "Offer Price"). Lockheed Martin shall extend the Offer, for
periods of no more than 60 days, until the earlier of (i) the one year
anniversary of the date hereof or (ii) 10 business days after the date on which
the last of the Authorized Carrier Conditions (as defined in Exhibit A hereto)
shall have been obtained. The obligation of Lockheed Martin to accept for
payment, and pay for, any Shares tendered pursuant to the Offer shall be
subject to the conditions set forth in Exhibit A (any of which may be waived in
whole or in part by Lockheed Martin in its sole discretion), and to the terms
and conditions of this Agreement. Lockheed Martin expressly reserves the right
to modify the terms and conditions of the Offer, except that, without the prior
written consent of COMSAT, Lockheed Martin shall not (i) reduce the number of
Shares subject to the Offer, (ii) waive the Minimum Condition (as defined in
Exhibit A hereto), (iii) reduce the Offer Price, (iv) modify or add to the
conditions set forth in Exhibit A, (v) except as provided in this Section
1.1(a), extend the term of the Offer, (vi) change the form of the consideration
payable in the Offer or (vii) make any other modifications that are otherwise
materially adverse to holders of COMSAT Common Stock. Notwithstanding the
foregoing, Lockheed Martin may, without the consent of COMSAT, (A) extend the
term of the Offer beyond any scheduled expiration date of the Offer (but not
beyond the two year anniversary of the date hereof) if, at any such scheduled
expiration date, any of the conditions to Lockheed Martin's obligation to
accept for payment, and pay for, Shares tendered pursuant to the Offer shall
not have been satisfied or waived and (B) extend the Offer (but not beyond the
two year anniversary of the date hereof) for any period required by any rule,
regulation, interpretation or position of the Securities and Exchange
Commission (the "SEC") or the staff thereof applicable to the Offer or any
other applicable Law (as hereinafter defined). Upon the terms and subject to
the conditions of the Offer, Lockheed Martin shall accept for payment and will
pay for, as soon as permitted under the terms of the Offer, Shares validly
tendered and not withdrawn prior to the expiration of the Offer. The date and
time at which the Offer shall close is referred to as the "Offer Closing Time".
 
                                      I-1
<PAGE>
 
   (b) Lockheed Martin shall not, nor shall it permit any of its affiliates to,
tender into the Offer any shares of COMSAT Common Stock beneficially owned by
it; provided, that shares of COMSAT Common Stock held beneficially or of record
by any plan, program or arrangement sponsored by Lockheed Martin or maintained
for the benefit of employees of Lockheed Martin or any of its Subsidiaries (as
hereinafter defined) shall be deemed not to be held by Lockheed Martin or an
affiliate thereof regardless of whether Lockheed Martin has, directly or
indirectly, the power to vote or control the disposition of such shares of
COMSAT Common Stock. COMSAT shall not, nor shall it permit any of its
Subsidiaries to, tender into the Offer any shares of COMSAT Common Stock
beneficially owned by it; provided, that shares of COMSAT Common Stock held
beneficially or of record by any plan, program or arrangement sponsored by
COMSAT or maintained for the benefit of employees of COMSAT or any of its
Subsidiaries shall be deemed not to be held by COMSAT regardless of whether
COMSAT has, directly or indirectly, the power to vote or control the
disposition of such shares of COMSAT Common Stock.
 
   (c) Notwithstanding anything to the contrary contained in this Agreement,
Lockheed Martin shall not be required to commence the Offer in any foreign
country where the commencement of the Offer, in Lockheed Martin's reasonable
opinion, would violate the applicable Law of such jurisdiction.
 
   (d) On the date of the commencement of the Offer, Lockheed Martin shall file
with the SEC a Tender Offer Statement on Schedule 14D-1 with respect to the
Offer, which will contain the offer to purchase and form of the related letter
of transmittal (together with any supplements or amendments thereto, the "Offer
Documents"). The Offer Documents shall comply as to form in all material
respects with the requirements of the Exchange Act and, on the date filed with
the SEC and when first published, sent or given to COMSAT's shareholders, shall
not contain any untrue statement of a material fact or omit to state any
material fact required to be stated therein or necessary in order to make the
statements therein, in light of the circumstances under which they were made,
not misleading, except that no representation is made by Lockheed Martin with
respect to information supplied by COMSAT in writing for inclusion in the Offer
Documents or incorporated therein by reference to any statement, report or
other document filed by or on behalf of COMSAT with the SEC. Upon obtaining
knowledge, Lockheed Martin or COMSAT shall correct promptly any information
provided by it for use in the Offer Documents if and to the extent that such
information shall have become false or misleading in any material respect, and
Lockheed Martin further shall take all steps necessary to amend or supplement
the Offer Documents and to cause the Offer Documents as so amended or
supplemented to be filed with the SEC and to be disseminated to COMSAT's
shareholders, in each case as and to the extent required by applicable federal
securities Laws. COMSAT and its counsel shall be given a reasonable opportunity
to review and comment on the Offer Documents prior to the filing of such Offer
Documents with the SEC. Lockheed Martin shall provide COMSAT and its counsel in
writing with any comments Lockheed Martin and its counsel may receive from the
SEC or its staff with respect to the Offer Documents promptly after the receipt
thereof. Lockheed Martin shall take all steps reasonably necessary to cause the
Offer Documents to be filed with the SEC and disseminated to the holders of
COMSAT Common Stock, in each case as, and to the extent, required by applicable
Law.
 
  Section 1.2 COMSAT Actions.
 
   (a) COMSAT hereby consents to the Offer and represents that its Board of
Directors, at a meeting duly called and held, has by resolutions duly adopted,
and not rescinded or modified, by a unanimous vote (excluding any directors
absent and any directors who recused themselves pursuant to Section 8.06 of
COMSAT's Articles of Incorporation) (i) determined as of the date hereof that
the Offer and the Merger are fair to the shareholders of COMSAT, are advisable
and are in the best interests of the shareholders of COMSAT, (ii) subject to
the terms and conditions set forth herein, approved the Offer, the Merger and
this Agreement, which approval constitutes approval of the Merger and this
Agreement for purposes of Section 29-364 of DCBCA, (iii) directed that the
Merger and this Agreement be submitted to a vote of the shareholders of COMSAT,
which direction constitutes the direction required by Section 29-366 of the
DCBCA with respect to the Merger and this Agreement and (iv) recommended
acceptance of the Offer and approval of the Merger and this Agreement by the
shareholders of COMSAT, which approval, if obtained, will constitute approval
of the Merger and this
 
                                      I-2
<PAGE>
 
Agreement for purposes of Section 29-367 of DCBCA. COMSAT further represents
that Donaldson, Lufkin & Jenrette Securities Corporation has delivered to the
Board of Directors of COMSAT its opinion that as of the date hereof the
consideration to be received in the Offer and the Merger by holders of shares
of COMSAT Common Stock is fair to the holders of COMSAT Common Stock from a
financial point of view.
 
   (b) COMSAT shall, subject to the provisions of this Agreement (i) file with
the SEC a Solicitation/Recommendation Statement on Schedule 14D-9 (the
"Schedule 14D-9") containing a recommendation of acceptance of the Offer and
approval of the Merger and this Agreement by the shareholders of COMSAT and
(ii) mail such Schedule 14D-9 to the shareholders of COMSAT; provided, that
subject to the provisions of Section 6.4(b) hereof, such recommendation may be
withdrawn, modified or amended. Such Schedule 14D-9 shall be, if so requested
by Lockheed Martin, filed on the same date as Lockheed Martin's Schedule 14D-1
is filed and mailed together with the Offer Documents; provided, that in any
event the Schedule 14D-9 shall be filed and mailed no later than 10 business
days following the commencement of the Offer. The Schedule 14D-9 shall comply
as to form in all material respects with the requirements of the Exchange Act
and, on the date filed with the SEC and when first published, sent or given to
COMSAT's shareholders, shall not contain any untrue statement of a material
fact or omit to state any material fact required to be stated therein or
necessary in order to make the statements therein, in light of the
circumstances under which they were made, not misleading, except that no
representation is made by COMSAT with respect to information supplied by
Lockheed Martin in writing for inclusion in the Schedule 14D-9. Upon obtaining
knowledge, each of COMSAT and Lockheed Martin shall correct promptly any
information provided by it for use in the Schedule 14D-9 if and to the extent
that such information shall have become false or misleading in any material
respect, and COMSAT further shall take all steps necessary to amend or
supplement the Schedule 14D-9 and to cause the Schedule 14D-9 as so amended or
supplemented to be filed with the SEC and disseminated to COMSAT's
shareholders, in each case as and to the extent required by applicable federal
securities Laws. Lockheed Martin and its counsel shall be given a reasonable
opportunity to review and comment on the Schedule 14D-9, and each such
amendment or supplement, prior to COMSAT's filing of the Schedule 14D-9 or such
supplement or amendment, as the case may be, with the SEC. COMSAT shall provide
Lockheed Martin and its counsel in writing with any comments COMSAT or its
counsel may receive from the SEC or its staff with respect to the Schedule 14D-
9 or such supplement or amendment, as the case may be, promptly after the
receipt thereof.
 
   Section 1.3 Shareholder Lists. In connection with the Offer, at the request
of Lockheed Martin, from time to time after the date hereof, COMSAT shall
promptly furnish Lockheed Martin with mailing labels, security position
listings and any available listing or computer file containing the names and
addresses of the record holders of the Shares as of a recent date and shall
furnish Lockheed Martin with such information and assistance as Lockheed Martin
or its agents may reasonably request in communicating the Offer to the record
and beneficial holders of Shares. Subject to the requirements of applicable
Law, and except for such steps as are necessary to disseminate the Offer
Documents and any other documents necessary to consummate the Merger, Lockheed
Martin shall hold in confidence the information contained in any such labels,
listings and files, and the additional information referred to in the preceding
sentence, will use such information only in connection with the Offer and the
Merger and, if this Agreement shall be terminated, shall, upon request, deliver
to COMSAT all copies of such information then in its possession or control or
in the possession or control of its agents or representatives.
 
                                   ARTICLE II
 
                               RELATED AGREEMENTS
 
   Section 2.1 Registration Rights Agreement. Simultaneous with the execution
and delivery of this Agreement, Lockheed Martin and COMSAT shall execute and
deliver the Registration Rights Agreement, substantially in the form attached
hereto as Exhibit B (the "Registration Rights Agreement"), with respect to the
Shares.
 
                                      I-3
<PAGE>
 
   Section 2.2 Shareholders Agreement. Simultaneous with the execution and
delivery of this Agreement, Lockheed Martin and COMSAT shall execute and
deliver the Shareholders Agreement, substantially in the form attached hereto
as Exhibit C (the "Shareholders Agreement").
 
   Section 2.3 Carrier Acquisition Agreement. Simultaneous with the execution
and delivery of this Agreement, Lockheed Martin, Offer Subsidiary, COMSAT and
COMSAT Government Systems, Inc., a Delaware corporation ("COMSAT Carrier
Subsidiary"), shall enter into an agreement pursuant to which COMSAT Carrier
Subsidiary shall be merged with and into Offer Subsidiary, which agreement
shall be substantially in the form attached hereto as Exhibit D (the "Carrier
Acquisition Agreement," and the transactions contemplated by the Carrier
Acquisition Agreement, the "Carrier Acquisition"). (This Agreement, the
Registration Rights Agreement, the Shareholders Agreement and the Carrier
Acquisition Agreement are hereinafter collectively referred to as the
"Transaction Agreements"). This Agreement contemplates the transactions set
forth in the Carrier Acquisition Agreement.
 
                                  ARTICLE III
 
                                   THE MERGER
 
   Section 3.1 The Merger. Upon the terms and subject to the conditions hereof,
and in accordance with the DCBCA and the Delaware General Corporation Law (the
"DGCL"), at the Effective Time (as hereinafter defined) COMSAT shall be merged
with and into Acquisition Sub (the "Forward Merger") as soon as practicable
following the satisfaction or waiver of the conditions set forth in Section
3.15 hereof or on such other date as the parties hereto may agree; provided,
however, that if the conditions in subsections (a) and (b) of such Section 3.15
are satisfied, but any of the conditions in Section 3.15(c) are not satisfied,
then Acquisition Sub shall be merged with and into COMSAT at the Effective Time
(the "Reverse Merger"). At the Effective Time, if the Forward Merger is
effected, then the separate existence of COMSAT shall cease and Acquisition Sub
shall continue as the surviving corporation under the name "COMSAT" or, if the
Reverse Merger is effected, then the separate existence of Acquisition Sub
shall cease and COMSAT shall continue as the surviving corporation. The
surviving corporation of the Forward Merger or the Reverse Merger, as the case
may be, shall be herein referred to as the "Surviving Corporation" and the
Forward Merger and Reverse Merger shall alternatively be referred to as the
"Merger."
 
   Section 3.2 Effective Time; Closing. The Merger shall be consummated by (i)
filing with the Department of Consumer and Regulatory Affairs of the District
of Columbia (the "DCRA") articles of merger, executed and filed in accordance
with Section 29-368 of the DCBCA and such other documents as are required by
Section 29-371 of the DCBCA and (ii) filing with the Secretary of State of the
State of Delaware a certificate of merger, executed and filed in accordance
with Sections 103 and 252 of the DGCL (the time the Merger becomes effective
being referred to as the "Effective Time"). The parties will cooperate to cause
the Effective Time to occur outside of New York Stock Exchange ("NYSE") trading
hours. The Merger shall be effective upon the latest to occur of (i) the
issuance by the DCRA of a certificate of merger with respect thereto pursuant
to Section 29-369 of the DCBCA, (ii) the acceptance for filing of the
certificate of merger by the Secretary of State of the State of Delaware
pursuant to Section 252 of the DGCL and (iii) the time, if any, specified as
the effective time of the Merger in the articles of merger filed in accordance
with the DCBCA and the certificate of merger filed in accordance with the DGCL.
Prior to the filings referred to in this Section 3.2, a closing (the "Closing")
will be held at the offices of O'Melveny & Myers LLP, 555 13th Street, N.W.,
Suite 500 West, Washington, D.C. 20004-1109 (or such other place as the parties
may agree), for the purpose of confirming all of the foregoing no later than
the second business day after satisfaction or waiver of all the conditions set
forth in Section 3.15 (the date of the Closing herein referred to as the
"Closing Date").
 
   Section 3.3 Effects of the Merger. The Merger shall have the effects set
forth in Section 29-370 of the DCBCA and Section 259 of the DGCL. As of the
Effective Time, the Surviving Corporation shall be a wholly-owned Subsidiary of
Lockheed Martin.
 
                                      I-4
<PAGE>
 
   Section 3.4 Certificate of Incorporation and By-Laws. If the Forward Merger
is consummated, the Certificate of Incorporation and By-Laws of Acquisition
Sub, each as in effect at the Effective Time, shall be the Certificate of
Incorporation and By-Laws of the Surviving Corporation, until amended in
accordance with applicable Law, except that Article FIRST of the Certificate of
Incorporation shall be amended so that it reads in its entirety as follows:
"The name of the corporation is COMSAT Corporation". If the Reverse Merger is
consummated, the Articles of Incorporation of COMSAT shall be amended at the
Effective Time to read in their entirety as set forth in Exhibit E hereto and
shall be the Articles of Incorporation of the Surviving Corporation, and the
By-Laws of COMSAT as in effect at the Effective Time shall be the By-Laws of
the Surviving Corporation, each until amended in accordance with applicable
Law.
 
   Section 3.5 Directors. The directors of Acquisition Sub at the Effective
Time shall be the initial directors of the Surviving Corporation and will hold
office from the Effective Time until their respective successors are duly
elected or appointed and qualify in the manner provided in the Certificate of
Incorporation or Articles of Incorporation of the Surviving Corporation, as the
case may be, and the By-Laws of the Surviving Corporation, or as otherwise
provided by Law.
 
   Section 3.6 Officers. The officers of COMSAT at the Effective Time shall be
the initial officers of the Surviving Corporation and will hold office from the
Effective Time until their respective successors are duly elected or appointed
and qualify in the manner provided in the Certificate of Incorporation or
Articles of Incorporation of the Surviving Corporation, as the case may be, and
the By-Laws of the Surviving Corporation, or as otherwise provided by Law.
 
   Section 3.7 Effect on Capital Stock. At the Effective Time:
 
   (a) Each share of COMSAT Common Stock issued and outstanding immediately
prior to the Effective Time (other than shares of COMSAT Common Stock held in
the treasury of COMSAT, held by Offer Subsidiary, held by Lockheed Martin, if
any, and Dissenting Shares (as hereinafter defined), if any) shall, by virtue
of the Merger and without any action on the part of the holder thereof, be
converted into the right to receive 0.5 shares of Lockheed Martin common stock,
par value $1 per share (the "Lockheed Martin Common Stock") (as subject to
adjustment pursuant to Section 3.14 hereof, the "Merger Consideration"),
issuable to the holder thereof upon the surrender of the certificate formerly
representing such share of COMSAT Common Stock (except as provided in Section
6.13 hereof).
 
   (b) Each share of COMSAT Common Stock held in the treasury of COMSAT, each
share of COMSAT Common Stock held by Offer Subsidiary, and each share of COMSAT
Common Stock held by Lockheed Martin, if any, immediately prior to the
Effective Time shall, by virtue of the Merger and without any action on the
part of the holder thereof, be cancelled and retired and cease to exist and no
consideration shall be received therefor; provided, that shares of COMSAT
Common Stock held beneficially or of record by any plan, program or arrangement
sponsored or maintained for the benefit of employees of Lockheed Martin or
COMSAT or any of their respective Subsidiaries shall be deemed not to be held
by Lockheed Martin, Offer Subsidiary or COMSAT regardless of whether Lockheed
Martin, Offer Subsidiary or COMSAT has, directly or indirectly, the power to
vote or control the disposition of such shares of COMSAT Common Stock.
 
   (c) In the case of the Forward Merger, each share of common stock, par value
$1.00 per share, of Acquisition Sub issued and outstanding immediately prior to
the Effective Time shall, by virtue of the Merger and without any action on the
part of the holder thereof remain outstanding as one share of the Surviving
Corporation, or in the case of the Reverse Merger, be converted into and
exchangeable for one share of common stock of the Surviving Corporation.
 
   Section 3.8 Dissenting Shares. Notwithstanding anything in this Agreement to
the contrary, shares of COMSAT Common Stock which are issued and outstanding
immediately prior to the Effective Time and which are held by shareholders who
have not voted such shares of COMSAT Common Stock in favor of the Merger and
shall have delivered a written demand for appraisal of such shares of COMSAT
Common Stock in the manner provided in Section 29-373 of the DCBCA (the
"Dissenting Shares") shall not be converted into or
 
                                      I-5
<PAGE>
 
be exchangeable for the right to receive the Merger Consideration, unless and
until such holder shall have failed to perfect or shall have effectively
withdrawn or lost such holder's right to appraisal and payment under the DCBCA.
If such holder shall have so failed to perfect or shall have effectively
withdrawn or lost such right, such holder's shares of COMSAT Common Stock shall
thereupon be deemed to have been converted into and to have become exchangeable
for, at the Effective Time, the right to receive the Merger Consideration.
 
   Section 3.9 Exchange of Stock.
 
   (a) Prior to the Effective Time, Lockheed Martin shall designate a bank or
trust company reasonably acceptable to COMSAT to act as exchange agent for the
holders of the shares of COMSAT Common Stock in connection with the Merger (the
"Exchange Agent"). At the Effective Time, Lockheed Martin will deposit with the
Exchange Agent, in trust for the benefit of holders of shares of COMSAT Common
Stock, certificates representing the Lockheed Martin Common Stock issuable
pursuant to Section 3.7(a) hereof in exchange for outstanding shares of COMSAT
Common Stock. Lockheed Martin shall make available to the Exchange Agent cash
sufficient to pay cash in lieu of fractional shares pursuant to Section 3.10
hereof and any dividends and other distributions pursuant to Section 3.9(d)
hereof. Any cash and certificates of Lockheed Martin Common Stock deposited
with the Exchange Agent shall hereinafter be referred to as the "Exchange
Fund".
 
   (b) Promptly after the Effective Time, the Exchange Agent shall mail to each
record holder, as of the Effective Time, of an outstanding certificate or
certificates which immediately prior to the Effective Time represented shares
of COMSAT Common Stock (the "Certificates") a form letter of transmittal (which
shall specify that delivery shall be effected, and risk of loss and title to
the Certificates shall pass, only upon proper delivery of the Certificates to
the Exchange Agent) and instructions for effecting the surrender of such
Certificates in exchange for the applicable Merger Consideration in such form
as Lockheed Martin shall reasonably specify. Upon surrender to the Exchange
Agent of a Certificate, together with such letter of transmittal duly executed,
and any other required documents, the holder of such Certificate shall be
entitled to promptly receive in exchange therefor (A) one or more shares of
Lockheed Martin Common Stock representing, in the aggregate, the whole number
of shares that such holder has the right to receive pursuant to Section 3.7(a)
hereof (after taking into account all shares of COMSAT Common Stock then held
by such holder) and (B) a check in the amount equal to the cash that such
holder has the right to receive pursuant to the provisions of this Article III,
including cash in lieu of any fractional shares of Lockheed Martin Common Stock
pursuant to Section 3.10 hereof. No interest will be paid or will accrue on any
cash payable pursuant to Section 3.9(d) hereof or Section 3.10 hereof upon the
surrender of the Certificates. All distributions to holders of Certificates
shall be subject to any applicable federal, state, local and foreign tax
withholding, and such withheld amounts shall be treated for all purposes of
this Agreement as having been paid to the holder of Certificates in respect of
which such deduction and withholding was made. If the Merger Consideration is
to be distributed to a Person (as defined below) other than the Person in whose
name the Certificate surrendered is registered, it shall be a condition of such
distribution that the Certificate so surrendered shall be properly endorsed or
otherwise in proper form for transfer (including signature guarantees, if
required by the Surviving Corporation in its sole discretion) and that the
Person requesting such payment shall pay any transfer or other taxes required
by reason of the payment to a Person other than the registered holder of the
Certificate surrendered or establish to the satisfaction of the Surviving
Corporation that such tax has been paid or is not applicable. Until surrendered
in accordance with the provisions of this Section 3.9, each Certificate (other
than Certificates representing shares of COMSAT Common Stock held by Lockheed
Martin or any Subsidiary of Lockheed Martin, shares of COMSAT Common Stock held
in the treasury of COMSAT or held by any Subsidiary of COMSAT and Dissenting
Shares) shall represent for all purposes only the right to receive the Merger
Consideration. The Surviving Corporation shall pay all charges and expenses,
including those of the Exchange Agent, in connection with the distribution of
the Merger Consideration. For purposes of this Agreement, the term "Person"
means any individual, firm, trust, partnership, joint venture, association,
corporation, limited liability company, unincorporated organization,
Governmental Authority (as hereinafter defined), or other entity including,
without limitation, the International Telecommunications Satellite Organization
("INTELSAT") or the International Maritime Satellite Organization ("Inmarsat").
 
 
                                      I-6
<PAGE>
 
   (c) After the Effective Time, there shall be no transfers on the stock
transfer books of the Surviving Corporation of the shares of COMSAT Common
Stock which were outstanding immediately prior to the Effective Time. If, after
the Effective Time, Certificates are presented to the Surviving Corporation,
they shall be cancelled and exchanged for the Merger Consideration in
accordance with the procedures set forth in this Section 3.9.
 
   (d) No dividends or other distributions declared or made with respect to
shares of Lockheed Martin Common Stock with a record date after the Effective
Time shall be paid to the holder of any unsurrendered Certificate with respect
to the shares of Lockheed Martin Common Stock that such holder would be
entitled to receive upon surrender of such Certificate and no cash payment in
lieu of fractional shares of Lockheed Martin Common Stock shall be paid to any
such holder pursuant to Section 3.10 hereof until such holder shall surrender
such Certificate in accordance with Section 3.9(b) hereof. Subject to the
effect of applicable Laws, including, without limitation, Laws of escheat,
following surrender of any such Certificate, there shall be paid to such holder
of shares of Lockheed Martin Common Stock issuable in exchange therefor,
without interest, (a) promptly after the time of such surrender, the amount of
any cash payable in lieu of fractional shares of Lockheed Martin Common Stock
to which such holder is entitled pursuant to Section 3.10 hereof and the amount
of dividends or other distributions with a record date after the Effective Time
theretofore paid with respect to such whole shares of Lockheed Martin Common
Stock, and (b) at the appropriate payment date, the amount of dividends or
other distributions with a record date after the Effective Time but prior to
such surrender and a payment date subsequent to such surrender payable with
respect to such shares of Lockheed Martin Common Stock.
 
   (e) All shares of Lockheed Martin Common Stock issued and cash paid upon
conversion of shares of COMSAT Common Stock in accordance with the terms of
this Article III (including any cash paid pursuant to Section 3.9(d) or Section
3.10 hereof) shall be deemed to have been issued or paid in full satisfaction
of all rights pertaining to the shares of COMSAT Common Stock.
 
   Section 3.10 No Fractional Shares of Lockheed Martin Common Stock.
 
   (a) No certificates or scrip representing fractional shares of Lockheed
Martin Common Stock shall be issued upon the surrender for exchange of
Certificates and such fractional share interests will not be considered
deliverable shares under Section 3.7(a) hereof, and will not entitle the owner
thereof to vote or to have any rights of a shareholder of Lockheed Martin or a
holder of shares of Lockheed Martin Common Stock.
 
   (b) Notwithstanding any other provision of this Agreement, each holder of
shares of COMSAT Common Stock exchanged pursuant to the Merger who would
otherwise have been entitled to receive a fraction of a share of Lockheed
Martin Common Stock (after taking into account all Certificates delivered by
such holder) shall receive, in lieu thereof, cash (without interest) in an
amount equal to the product of (i) such fractional part of a share of Lockheed
Martin Common Stock multiplied by (ii) the closing price per share of Lockheed
Martin Common Stock reported on the NYSE Composite Tape on the last full
trading day prior to the Effective Time. As promptly as practicable after the
determination of the amount of cash, if any, to be paid to holders of COMSAT
Common Stock with respect to fractional interests, the Exchange Agent shall so
notify Lockheed Martin, and Lockheed Martin shall or shall cause the Surviving
Corporation to deposit such amount with the Exchange Agent and shall cause the
Exchange Agent to forward payments to such holders of fractional share
interests subject to and in accordance with the terms hereof.
 
   Section 3.11 Termination of Exchange Fund. Any portion of the Exchange Fund
which remains undistributed to the holders of Certificates for twelve months
after the Effective Time shall be delivered to the Surviving Corporation or
otherwise on the instruction of the Surviving Corporation, and any holders of
the Certificates who have not theretofore complied with this Article III shall,
subject to the effect of applicable Laws, including without limitation, Laws of
escheat, thereafter look only to the Surviving Corporation and Lockheed Martin
for the Merger Consideration with respect to the shares of COMSAT Common Stock
formerly represented thereby to which such holders are entitled pursuant to
Section 3.7 hereof and Section 3.9
 
                                      I-7
<PAGE>
 
hereof, any cash in lieu of fractional shares of Lockheed Martin Common Stock
to which such holders are entitled pursuant to Section 3.10 hereof and any
dividends or distributions with respect to shares of Lockheed Martin Common
Stock to which such holders are entitled pursuant to Section 3.9(d) hereof. Any
such portion of the Exchange Fund remaining unclaimed by holders of shares of
COMSAT Common Stock five years after the Effective Time (or such earlier date
immediately prior to such time as such amounts would otherwise escheat to or
become property of any Governmental Authority (as defined below)) shall, to the
extent permitted by Law, become the property of the Surviving Corporation free
and clear of any claims or interest of any Person previously entitled thereto.
For purposes of this Agreement, the term "Governmental Authority" means any
agency, bureau, commission, court, department, officer, political subdivision,
or other instrumentality of any nation or government, any region, state, or
other political subdivision thereof whether federal, state, county or local,
domestic or foreign (excluding INTELSAT or Inmarsat), or any entity exercising
executive, legislative, judicial, regulatory or administrative functions of or
pertaining to government, and any Person owned or controlled through stock or
capital ownership or otherwise by any of the foregoing.
 
   Section 3.12 No Liability. None of Lockheed Martin, Acquisition Sub, COMSAT,
the Surviving Corporation or the Exchange Agent shall be liable to any Person
in respect of any Merger Consideration from the Exchange Fund delivered to a
public official pursuant to any applicable abandoned property, escheat or
similar Law.
 
   Section 3.13 Lost Certificates. If any Certificate shall have been lost,
stolen or destroyed, upon the making of an affidavit of that fact by the Person
claiming such Certificate to be lost, stolen or destroyed and, if required by
the Surviving Corporation, the posting by such Person of a bond in such
reasonable amount as the Surviving Corporation may direct as indemnity against
any claim that may be made against it with respect to such Certificate, the
Exchange Agent will deliver in exchange for such lost, stolen or destroyed
Certificate the applicable Merger Consideration with respect to the shares of
COMSAT Common Stock formerly represented thereby, any cash in lieu of
fractional shares of Lockheed Martin Common Stock, and unpaid dividends and
distributions on shares of Lockheed Martin Common Stock deliverable in respect
thereof, pursuant to this Agreement.
 
   Section 3.14 Certain Adjustments. Without limiting any other provision of
this Agreement, if, between the date of this Agreement and the Effective Time,
the outstanding shares of Lockheed Martin Common Stock shall be changed into a
different number or a different class or series of shares by reason of any
reclassification, recapitalization, stock split, reverse stock split,
combination or exchange of shares or any other similar transaction, or any
dividend payable in stock or other securities shall be declared thereon with a
record date within such period, the Merger Consideration established pursuant
to the provisions of Section 3.7 hereof shall be adjusted accordingly to
provide to the holders of COMSAT Common Stock the same economic effect as
contemplated by this Agreement prior to such reclassification,
recapitalization, stock split, reverse stock split, combination, exchange or
dividend.
 
   Section 3.15 Conditions to Closing of Merger.
 
   (a) The obligation of each party to effect the Merger is subject to the
satisfaction at or prior to the Effective Time of the following conditions:
 
     (i) Offer Subsidiary shall have purchased Shares pursuant to the Offer;
 
     (ii) the Satellite Act, and other applicable Laws, shall have been
  amended or repealed, and all applicable proceedings before the Federal
  Communications Commission ("FCC") or other Governmental Authority necessary
  to implement such amendment or repeal shall have been completed to the
  extent necessary to permit the consummation of the Merger as contemplated
  by the terms of this Agreement;
 
     (iii) any applicable waiting period related to the Merger under the
  Antitrust Laws (as hereinafter defined) shall have terminated or expired
  and all consents or approvals required under the Antitrust Laws shall have
  been received;
 
                                      I-8
<PAGE>
 
     (iv) the shares of Lockheed Martin Common Stock to be issued in the
  Merger and such other shares to be reserved for issuance in connection with
  the Merger shall have been approved upon official notice of issuance for
  listing on the NYSE; and
 
     (v) the Form S-4 (as hereinafter defined) shall have been declared
  effective by the SEC under the Securities Act of 1933, as amended, and all
  rules and regulations promulgated thereunder (the "Securities Act"). No
  stop order suspending the effectiveness of the Form S-4 shall have been
  issued by the SEC and no proceedings for that purpose shall have been
  initiated or threatened by the SEC; and
 
     (vi) the shareholders of COMSAT shall have approved the Merger and this
  Agreement pursuant to Section 29-367 of the DCBCA.
 
   (b) The obligations of Lockheed Martin and Acquisition Sub to effect the
Merger are further subject to the satisfaction at or prior to the Effective
Time of the following conditions:
 
     (i) (A) after the date of this Agreement, there shall not have been any
  change in existing Law or any new Law promulgated, enacted, enforced or
  deemed applicable to COMSAT or to the transactions contemplated by this
  Agreement nor (B) shall INTELSAT or Inmarsat have adopted a plan for
  privatization, or have been privatized, in whole or in part, in a manner or
  pursuant to terms and conditions (or, in the case of an adopted plan,
  proposed terms and conditions), in the case of either clause (A) or clause
  (B) that Lockheed Martin determines in good faith (after consultation with
  COMSAT) would reasonably be expected to have a Significant Adverse Effect
  (as defined below);
 
     (ii) all consents and approvals from Governmental Authorities (including
  the FCC) or any other Person required for the consummation of the Merger as
  contemplated by the terms of this Agreement shall have been granted, except
  where the failure to obtain such consent or approval, individually or in
  the aggregate, would not reasonably be expected to have a Significant
  Adverse Effect; and
 
     (iii) since the date of this Agreement, there shall not have occurred
  any event that has had or would reasonably be expected to have a
  Significant Adverse Effect.
 
   For purposes of this Agreement, the term "Significant Adverse Effect" means
a Material Adverse Effect on COMSAT (as hereinafter defined, but including, for
purposes of determining whether there has been a Significant Adverse Effect,
any effects or changes arising out of, resulting from or relating to general
economic, financial or industry conditions) of such seriousness and
significance that a reasonable businessperson in similar circumstances would
not proceed with the Merger on the terms and conditions set forth in this
Agreement.
 
   COMSAT will furnish Lockheed Martin with such certificates and other
documents to evidence the fulfillment of the conditions set forth in this
Section 3.15(b) as Lockheed Martin may reasonably request.
 
   (c) The obligation of each party to effect the Forward Merger is further
subject to the satisfaction at or prior to the Effective Time of the following
conditions and if any of the following conditions are not satisfied, but the
conditions set forth in Sections 3.15(a) and 3.15(b) are satisfied, the Reverse
Merger shall be effected:
 
     (i) the aggregate fair market value of the shares of Lockheed Martin
  Common Stock, deliverable pursuant to Section 3.7(a) hereof upon
  consummation of the Forward Merger, based upon the most recent closing
  price of such stock on the NYSE Composite Tape on the last full trading day
  prior to the Effective Time (the "Stock Value"), would be at least 40% of
  the sum of (A) the Stock Value, (B) the aggregate amount paid by Lockheed
  Martin to purchase Shares pursuant to the Offer, (C) cash payable in
  respect of Dissenting Shares (assuming for these purposes that the per
  share amount payable in respect of Dissenting Shares is $50 per share), and
  (D) cash payable in respect of fractional shares (assuming for these
  purposes that each holder of record of COMSAT Common Stock as of the close
  of the last trading day prior to the Effective Time is entitled to receive
  $50 in respect of fractional share interests);
 
     (ii) COMSAT shall have received from Skadden, Arps, Slate, Meagher, &
  Flom LLP, counsel to COMSAT, a written opinion dated as of the Closing
  Date, substantially in the form attached hereto as Exhibit F, based upon
  representations of COMSAT and Lockheed Martin (including representations
 
                                      I-9
<PAGE>
 
  relating to any material transactions currently under consideration by
  COMSAT and Lockheed Martin, respectively) contained in tax certificates.
  Such representations shall be those that customarily would be required in
  similar circumstances. The written opinion shall be substantially to the
  effect that the Forward Merger will be treated for U.S. federal income tax
  purposes as a reorganization qualifying under the provision of Section
  368(a) of the Internal Revenue Code of 1986, as amended (the "Code");
 
     (iii) Lockheed Martin shall have received from King & Spalding, counsel
  to Lockheed Martin, a written opinion dated as of the Closing Date,
  substantially in the form attached hereto as Exhibit F, based upon
  representations of COMSAT and Lockheed Martin (including representations
  relating to any material transactions currently under consideration by
  COMSAT and Lockheed Martin, respectively) contained in tax certificates.
  Such representations shall be those that customarily would be required in
  similar circumstances. The written opinion shall be substantially to the
  effect that the Forward Merger will be treated for U.S. federal income tax
  purposes as a reorganization qualifying under the provision of
  Section 368(a) of the Code; and
 
     (iv) all required consents or approvals from Governmental Authorities
  (including the FCC) or any other Person shall have been obtained to permit
  the consummation of the Forward Merger, except where the failure to obtain
  such consent or approval, individually or in the aggregate, would not
  reasonably be expected to have a material adverse effect on COMSAT's
  business.
 
                                   ARTICLE IV
 
                    REPRESENTATIONS AND WARRANTIES OF COMSAT
 
   Except as set forth in the disclosure schedule delivered prior to the
execution hereof to Lockheed Martin (the "COMSAT Disclosure Schedule") (each
section of which qualifies only the corresponding numbered representation and
warranty or covenant as specified therein), COMSAT represents and warrants to
Lockheed Martin and Acquisition Sub as follows:
 
   Section 4.1 Organization. Each of COMSAT and its Subsidiaries is a
corporation, limited liability company or limited partnership duly organized,
validly existing and in good standing under the Laws of the jurisdiction of its
organization or formation and has all requisite power and authority, as a
corporation, limited liability company or limited partnership, as the case may
be, to own, lease and operate its properties and to carry on its business as
now being conducted, except, in the case of Subsidiaries, where the failure to
be so organized, existing and in good standing or to have such power and
authority would not, either individually or in the aggregate, reasonably be
expected to have a Material Adverse Effect on COMSAT and except as set forth in
Section 4.1 of the COMSAT Disclosure Schedule. For purposes of this Agreement,
the term "Material Adverse Effect" shall mean any change or effect that is
materially adverse to (i) the business, properties, operations, results of
operations or financial condition of the referenced Person and its
Subsidiaries, taken as a whole, other than any effects or changes arising out
of, resulting from or relating to general economic, financial or industry
conditions or (ii) the ability of any of the referenced Person and its
Subsidiaries to perform its obligations under this Agreement and the Carrier
Acquisition Agreement. Each of COMSAT and its Subsidiaries is duly qualified or
licensed and in good standing to do business in each jurisdiction in which the
property owned, leased or operated by it or the nature of the business
conducted by it makes such qualification or licensing necessary, except in such
jurisdictions where the failure to be so duly qualified or licensed and in good
standing, either individually or in the aggregate, would not reasonably be
expected to have a Material Adverse Effect on COMSAT and except as set forth in
Section 4.1 of the COMSAT Disclosure Schedule. COMSAT has heretofore delivered
or made available to Lockheed Martin accurate and complete copies of the
Articles of Incorporation and By-Laws (or other similar organizational
documents in the case of an entity other than a corporation), as currently in
effect, of COMSAT and each of its Subsidiaries. For purposes of this Agreement,
the term "Laws" shall mean collectively, any law, rule, regulation, statute,
writ, ordinance, judgment, decision, decree, ruling, Order (as hereinafter
defined), award, injunction or other official action of any Governmental
Authority.
 
 
                                      I-10
<PAGE>
 
   Section 4.2 Authority. COMSAT has full corporate power and authority to
execute and deliver each Transaction Agreement to which it is a party and
subject to the limitations of the Satellite Act, COMSAT's Articles of
Incorporation, and COMSAT's Bylaws to consummate the transactions contemplated
thereby. The execution and delivery of each such Transaction Agreement by
COMSAT and the consummation of the transactions contemplated thereby have been
duly and validly authorized by the Board of Directors of COMSAT and no other
corporate proceedings on the part of COMSAT are necessary to authorize any such
Transaction Agreement or to consummate the transactions contemplated thereby,
other than, with respect to the Merger, the approval of the Merger and this
Agreement by the shareholders of COMSAT and, with respect to the amendment to
COMSAT's Articles of Incorporation called for in the Shareholders Agreement
(the "Amendment"), the approval thereof by the Board of Directors and
shareholders of COMSAT as contemplated by the Shareholders Agreement. This
Agreement and each other Transaction Agreement has been duly and validly
executed and delivered by COMSAT and constitutes the valid and binding
agreement of COMSAT (and assuming due and valid authorization, execution and
delivery thereof by the other parties thereto) enforceable against COMSAT in
accordance with its terms, except to the extent that enforcement thereof may be
limited by bankruptcy, insolvency, reorganization, moratorium, fraudulent
conveyance or other similar Laws, now or hereafter in effect, relating to the
creditors' rights generally and general principles of equity (regardless of
whether enforceability is considered in a proceeding at law or in equity). The
approval of the Merger, this Agreement and the Amendment by two-thirds of the
votes entitled to be cast by all holders of COMSAT Common Stock is the only
vote of the holders of any class or series of the capital stock of COMSAT
required to approve any Transaction Agreement or the transactions contemplated
thereby. For purposes of this Agreement, the term "Subsidiary", when used with
respect to any Person, means, (i) any corporation or other entity of which
securities or other ownership interests having ordinary voting power to elect
50% or more of the board of directors or other persons performing similar
functions are at the time directly or indirectly owned by the Person or (ii) a
partnership, limited liability company, joint venture or similar entity or
arrangement however organized or constituted in which the Person or a
Subsidiary of the Person is, at the date of determination, a general partner,
limited partner or member, as the case may be, but only if the Person or its
Subsidiary is entitled at any time to receive 50% or more of the amounts
distributed or distributable by such partnership, limited liability company,
joint venture or other entity or pursuant to such arrangement to the partners
or members thereof or parties thereto, whether upon dissolution, termination or
otherwise.
 
   Section 4.3 Consents and Approvals; No Violations. Except for any applicable
requirements of the Securities Act, the Exchange Act, Antitrust Laws, the
Communications Act of 1934, as amended, and all rules and regulations
promulgated thereunder (the "Communications Act") and the Satellite Act, the
filing and recordation of articles and/or a certificate of merger with respect
to the Merger, as required by the DCBCA and the DGCL, respectively, the filing
with and approval of the NYSE and the SEC with respect to the delisting and
deregistering of the shares of COMSAT Common Stock, such filings and approvals
as may be required under the "takeover" or "blue sky" Laws of various states or
as disclosed in Section 4.3 of the COMSAT Disclosure Schedule, neither the
execution and delivery of this Agreement by COMSAT nor the consummation by
COMSAT of any transaction contemplated hereby will (i) conflict with or result
in any breach of any provision of the Articles of Incorporation or By-Laws of
COMSAT or the articles of incorporation or by-laws of any of its Subsidiaries
(other than those Subsidiaries which, either individually or in the aggregate,
would not be a "significant subsidiary" within the meaning of Regulation S-X
promulgated under the Securities Act) (each such Subsidiary, other than those
described in the preceding parenthetical, herein called a "Significant
Subsidiary"), (ii) require on the part of COMSAT, such Subsidiary or a
Significant Subsidiary any filing with, or the obtaining of any permit,
authorization, consent or approval of, any Governmental Authority or any other
Person, (iii) result in a violation or breach of, or constitute (with or
without due notice or lapse of time or both) a default (or give rise to any
right of termination, amendment, cancellation, acceleration or payment, or to
the creation of any mortgage, deed of trust, lien (statutory or otherwise),
pledge, hypothecation, charge, deposit arrangement, preference, priority,
security interest, restriction or transfer or encumbrance of any kind
(including, without limitation, any conditional sale contract, any capitalized
lease or any financing lease having substantially the same economic effect as
the foregoing and the filing of or agreement to give any financing
 
                                      I-11
<PAGE>
 
statement under the Uniform Commercial Code or comparable Law of any
jurisdiction to evidence any of the foregoing) (collectively, "Liens") under
any of the terms, conditions or provisions of any note, mortgage, indenture,
other evidence of indebtedness, guarantee, license, agreement or other
contract, instrument or obligation to which COMSAT or any of its Subsidiaries
is a party or by which any of them or any of their Assets may be bound
(including, without limitation, the COMSAT Contracts (as hereinafter defined))
or (iv) violate any Law applicable to COMSAT or any of its Subsidiaries or any
of their Assets (as defined below), except for such requirements, defaults,
rights or violations under clauses (ii), (iii) and (iv) above (x) which, either
individually or in the aggregate, would not reasonably be expected to have a
Material Adverse Effect on COMSAT or (y) which become applicable as a result of
the business or activities in which Lockheed Martin or Acquisition Sub is or
proposes to be engaged (other than the business or activities of COMSAT and its
Subsidiaries, considered independently of the ownership thereof by Lockheed
Martin and Acquisition Sub) or as a result of other facts or circumstances
specific to Lockheed Martin or Acquisition Sub. For purposes of this Agreement,
the term "Assets" means all assets, of whatever nature, tangible, intangible,
real or personal.
 
   Section 4.4 Capitalization.
 
   (a) As of the close of business on September 11, 1998, the authorized
capital stock of COMSAT consisted of (i) 100,000,000 shares of COMSAT Common
Stock, of which 52,494,820 shares were issued and outstanding of which
52,475,862 shares were Series I Common Stock, inclusive of shares subject to
restrictions, and 18,958 shares were Series II Common Stock, and (ii) 5,000,000
shares of Preferred Stock, without par value ("COMSAT Preferred Stock"), of
which no shares were issued and outstanding. Since the close of business on
September 11, 1998 through the date hereof, no shares of Series II Common Stock
in addition to those set forth in the preceding sentence have been issued. As
of the close of business on September 11, 1998, (i) 3,562,415 shares of COMSAT
Common Stock were issuable upon the exercise of outstanding vested and non-
vested options (the "COMSAT Stock Options") granted under COMSAT's stock option
plans (the "Stock Option Plans") and (ii) not more than 9,000 shares of COMSAT
Common Stock were issuable upon the exercise of other rights to acquire shares
of COMSAT Common Stock granted under other programs of COMSAT or any of its
Subsidiaries that afford to employees or directors of COMSAT and its
Subsidiaries the opportunity to acquire shares of COMSAT Common Stock, each as
amended (such programs together with the Stock Option Plans, the "COMSAT Stock
Plans"), copies of which have previously been delivered to Lockheed Martin.
Since the close of business on September 11, 1998, COMSAT has not granted any
COMSAT Stock Options, issued any other right to acquire shares of its capital
stock or granted any restricted shares or restricted share units of COMSAT
Common Stock under the COMSAT Stock Plans, or otherwise issued any shares of
its capital stock except (i) as permitted by this Agreement, (ii) as set forth
in Section 4.4(a) of the COMSAT Disclosure Schedule, (iii) upon exercise of the
COMSAT Stock Options or (iv) pursuant to a nondiscretionary grant under the
COMSAT Savings and Profit Sharing Plan, the COMSAT Employee Stock Purchase
Plan, or the COMSAT Investors Plus Plan in accordance with the current terms of
such Plan. Except as set forth above and as otherwise permitted in this
Agreement, there are not now, and at the Effective Time there will not be, any
Equity Securities of COMSAT issued or outstanding. For purposes of this
Agreement, the term "Equity Securities" of a Person means the capital stock of
the Person and all other securities (whether or not issued by such Person but
excluding any exchange traded or privately granted options) convertible into or
exchangeable or exercisable for any shares of its capital stock, all rights or
warrants to subscribe for or to purchase, all options for the purchase of, and
all calls, commitments, agreements, arrangements, undertakings or claims of any
character relating to, any shares of its capital stock and any securities
convertible into or exchangeable or exercisable for any of the foregoing.
 
   (b) All outstanding shares of capital stock of COMSAT are duly authorized,
validly issued, fully paid and nonassessable and are not subject to preemptive
rights.
 
   (c) Except with respect to the outstanding shares of COMSAT Common Stock and
the COMSAT Stock Options, there are no outstanding bonds, debentures, notes or
other indebtedness or other securities of COMSAT having the right to vote (or
convertible into, or exchangeable for, securities having the right to vote) on
any matters on which shareholders of COMSAT may vote.
 
 
                                      I-12
<PAGE>
 
   (d) Except as set forth in Section 4.4(d) of the COMSAT Disclosure Schedule
or with respect to the COMSAT Stock Options, the Shareholders Agreement, the
restrictions set forth at Sections 303 and 304 of the Satellite Act (47 U.S.C.
(S)(S) 733 and 734), resolutions by the Board of Directors of COMSAT (which
currently restrict the exercise of voting rights with respect to the voting of
shares of COMSAT Common Stock held by a shareholder that is not an Authorized
Carrier in excess of five per centum (5%) of the issued and outstanding COMSAT
Common Stock) and the restriction pursuant to Section 5.02(e) of COMSAT's
Articles of Incorporation (which currently limits ownership of COMSAT stock by
any shareholder that is not an Authorized Carrier to ten per centum (10%) of
the issued and outstanding COMSAT Common Stock), there is no agreement or
arrangement restricting the voting or transfer of the Equity Securities of
COMSAT.
 
   (e) Except as set forth in Section 4.4(e) of the COMSAT Disclosure Schedule,
there are no outstanding contractual obligations, commitments, understandings
or arrangements of COMSAT or any of its Subsidiaries to repurchase, redeem or
otherwise acquire, reacquire or make any payment in respect of any Equity
Securities of COMSAT or any of its Subsidiaries.
 
   (f) Except as contemplated by the Registration Rights Agreement, there are
no agreements or arrangements to which COMSAT or any of its Subsidiaries is a
party pursuant to which COMSAT is required to register its Equity Securities
under the Securities Act.
 
   Section 4.5 Absence of Certain Changes. Except (i) as set forth in Section
4.5 of the COMSAT Disclosure Schedule, (ii) as set forth in COMSAT's Annual
Report on Form 10-K for the year ended December 31, 1997 (the "COMSAT Form 10-
K"), COMSAT's Quarterly Reports on Form 10-Q for the three month periods ended
March 31, 1998 and June 30, 1998, respectively, or any other document filed
prior to the date hereof pursuant to Section 13(a) or 15(d) of the Exchange
Act, or (iii) as contemplated by this Agreement, from June 30, 1998 until the
date hereof, neither COMSAT nor any of its Subsidiaries has (x) taken any of
the prohibited actions set forth in Section 6.1 hereof, (y) suffered any
changes that, either individually or in the aggregate, would reasonably be
expected to have a Material Adverse Effect on COMSAT or (z) conducted its
business or operations in any material respect other than in the ordinary
course of business.
 
   Section 4.6 Reports. For the purposes of this Agreement, the "COMSAT SEC
Documents" means each registration statement, report, proxy statement or
information statement of COMSAT prepared by it since January 1, 1996, in the
form (including exhibits and any amendments thereto) filed with the SEC. As of
the respective filing dates, the COMSAT SEC Documents (i) complied as to form
in all material respects with the applicable requirements of the Securities Act
and the Exchange Act and (ii) did not contain any untrue statement of a
material fact or omit to state a material fact required to be stated therein or
necessary to make the statements made therein, in the light of the
circumstances under which they were made, not misleading. Each of the
consolidated balance sheets included in or incorporated by reference into the
COMSAT SEC Documents (including the related notes and schedules) fairly
presents the consolidated financial position of COMSAT and its Subsidiaries as
of its date, and each of the consolidated statements of income, retained
earnings and cash flows included in or incorporated by reference into the
COMSAT SEC Documents (including any related notes and schedules) fairly
presents the results of operations, retained earnings or cash flows, as the
case may be, of COMSAT and its Subsidiaries for the periods set forth therein
(subject, in the case of unaudited statements, to normal year-end audit
adjustments which would not be material in amount or effect), in each case in
accordance with United States generally accepted accounting principles ("GAAP")
consistently applied during the periods involved, except as may be noted
therein. None of COMSAT and its Subsidiaries has any Liabilities (as defined
below) required to be disclosed in a balance sheet of COMSAT or in the notes
thereto prepared in accordance with GAAP consistently applied except (a)
Liabilities reflected on, or reserved against in, a balance sheet of COMSAT or
in the notes thereto, and included in the COMSAT SEC Documents, (b) Liabilities
incurred since June 30, 1998 in the ordinary course of business and (c) as set
forth in Section 4.6 of the COMSAT Disclosure Schedule. For purposes of this
Agreement, the term "Liabilities" means all debts, claims, actions, demands,
rights, costs, expenses, liabilities, losses, damages, commitments and
obligations (in each case whether fixed, contingent or absolute, accrued or not
accrued, that would be required by GAAP to be reflected in financial statements
of COMSAT or disclosed in the notes thereto).
 
                                      I-13
<PAGE>
 
   Section 4.7 No Default. Except as set forth in Section 4.7 of the COMSAT
Disclosure Schedule, neither COMSAT nor any of its Subsidiaries is in default
or violation (and no event has occurred which with notice or the lapse of time
or both would constitute a default or violation) of any term, condition or
provision of (i) its articles of incorporation or by-laws (or other similar
organizational documents in the case of an entity other than corporation), (ii)
any note, mortgage, indenture other evidence of indebtedness, guarantee,
license, agreement or other contract, instrument or contractual obligation to
which COMSAT or any of its Subsidiaries is now a party or by which they or any
of their Assets may be bound, or (iii) any Law applicable to COMSAT or any of
its Subsidiaries, except for defaults or violations under clause (i), clause
(ii) and clause (iii) above that, (A) in the aggregate would not reasonably be
expected to have a Material Adverse Effect on COMSAT or (B) become applicable
as a result of the business or activities in which Lockheed Martin or
Acquisition Sub is or proposes to be engaged (other than the business or
activities of COMSAT and its Subsidiaries, considered independently of the
ownership thereof by Lockheed Martin and Acquisition Sub) or as a result of any
other facts or circumstances specific to Lockheed Martin or Acquisition Sub.
 
   Section 4.8 Litigation; Compliance with Law.
 
   (a) Except as set forth in Section 4.8(a) of the COMSAT Disclosure Schedule,
as of the date hereof, there are no actions, suits, claims, proceedings or
investigations pending or, to the knowledge of COMSAT, threatened, involving
COMSAT or any of its Subsidiaries or any of their respective Assets (or any
Person whose liability therefrom may have been retained or assumed by COMSAT or
any of its Subsidiaries either contractually or by operation of law), by or
before any court, Governmental Authority or by any other Person that, either
individually or in the aggregate, if determined adversely to COMSAT or such
Subsidiary, would reasonably be expected to have a Material Adverse Effect on
COMSAT.
 
   (b) Except as disclosed by COMSAT in COMSAT SEC Documents filed since
January 1, 1998 (the "Recent SEC Documents") or as set forth in Section 4.8(b)
of the COMSAT Disclosure Schedule, COMSAT and its Subsidiaries are now being
and, to the knowledge of COMSAT, since January 1, 1994 have been operated in
substantial compliance with all Laws, except for violations that, either
individually or in the aggregate, would not reasonably be expected to have a
Material Adverse Effect on COMSAT.
 
   Section 4.9 Employee Benefit Plans; ERISA.
 
   (a) Except as set forth in Section 4.9(a) of the COMSAT Disclosure Schedule,
(i) each "employee benefit plan" (as defined in Section 3(3) of the Employee
Retirement Income Security Act of 1974, as amended ("ERISA")), and all other
employee benefit, bonus, incentive, stock option (or other equity-based),
severance, change in control, welfare (including post-retirement medical and
life insurance) and fringe benefit plans (whether or not subject to ERISA)
maintained or sponsored by COMSAT or its Subsidiaries or any trade or business,
whether or not incorporated, that would be deemed a "single employer" within
the meaning of Section 4001 of ERISA (an "ERISA Affiliate"), for the benefit of
any employee or former employee of COMSAT or any of its ERISA Affiliates (the
"Plans") is, and has been, operated in all material respects in accordance with
its terms and in substantial compliance (including the making of filings with
Governmental Authorities) with all applicable Laws, including, without
limitation, ERISA and the applicable provisions of the Code, (ii) each of the
Plans intended to be "qualified" within the meaning of Section 401(a) of the
Code has been determined by the Internal Revenue Service (the "IRS") to be so
qualified and is not under audit by the IRS or the Department of Labor or the
subject of IRS review under the IRS Employee Plans Compliance Resolution System
and COMSAT knows of no fact or set of circumstances that is reasonably likely
to adversely affect such qualification, (iii) no material withdrawal liability
with respect to any "multiemployer plan" (as defined in Section 4001(a)(3) of
ERISA) would be incurred by COMSAT and its ERISA Affiliates in the event of a
withdrawal from such plan, (iv) no "reportable event", as such term is defined
in Section 4043(c) of ERISA (for which the 30-day notice requirement to the
Pension Benefit Guaranty Corporation ("PBGC") has not been waived), has
occurred with respect to any Plan that is subject to Title IV of ERISA, and (v)
there are no material pending or, to the knowledge of COMSAT, threatened claims
(other than routine claims for benefits) by, on behalf of or against any of the
Plans or any trusts related thereto. Set forth in
 
                                      I-14
<PAGE>
 
Section 4.9(a) of the COMSAT Disclosure Schedule is a list of all Plans. A true
and complete copy of each of the Plans and, if applicable, the summary plan
description, any summary of material modifications, the most recent Form 5500,
and the most recently issued IRS determination letter and actuarial report with
respect to each of the Plans has previously been provided to Lockheed Martin
and Acquisition Sub.
 
   (b) (i) No Plan has incurred an "Accumulated Funding Deficiency" (as defined
in Section 302 of ERISA or Section 412 of the Code), whether or not waived,
(ii) neither COMSAT nor any ERISA Affiliate has incurred any Liability under
Title IV of ERISA except for required premium payments to the PBGC, which
payments have been made when due, and no events have occurred which are
reasonably likely to give rise to any Liability of COMSAT or an ERISA Affiliate
under Title IV of ERISA or which could reasonably be anticipated to result in
any claims being made against Lockheed Martin or its affiliates by the PBGC,
(iii) no amendment has been adopted which would require the posting of security
in accordance with Section 401(a)(29) of the Code, and (iv) COMSAT has not
incurred any material withdrawal liability (including any contingent or
secondary withdrawal liability) within the meaning of Section 4201 and 4204 of
ERISA to any multiemployer plan (within the meaning of Section 4001(a)(3) of
ERISA) which has not been satisfied in full.
 
   (c) Except as set forth in Section 4.9(c) of the COMSAT Disclosure Schedule,
with respect to each Plan that is subject to Title IV of ERISA or that provides
post-retirement life or medical insurance or other post-employment benefits
(other than continuation coverage pursuant to Section 4980B(f) of the Code or
Sections 601 to 606 of ERISA) (i) COMSAT has provided to Acquisition Sub a
complete copy of the most recent actuarial valuation report prepared for such
Plan, (ii) the assets and liabilities in respect of the accrued benefits as set
forth in the most recent actuarial valuation report prepared by the Plan's
actuary fairly present the funded status of such Plan in all material respects,
and (iii) since the date of such valuation report there has been no material
adverse change in the funded status of any such Plan.
 
   (d) Neither COMSAT nor any ERISA Affiliate has failed to make any
contribution or payment to any Plan or multiemployer plan which in either case
has resulted or could result in the imposition of a Lien or the posting of a
bond or other security under ERISA or the Code.
 
   (e) Except as set forth in Section 4.9(e) of the COMSAT Disclosure Schedule
or as expressly provided for in this Agreement, the consummation of the
transactions contemplated by this Agreement will not (i) entitle any current or
former employee, officer or director of COMSAT or any Subsidiary to severance
pay, unemployment compensation or any other payment, (ii) accelerate the time
of payment or vesting, or increase the amount of compensation due any such
employee, officer or director or (iii) violate any provision of any Plan
document.
 
   (f) Except as set forth in Section 4.9(f) of the COMSAT Disclosure Schedule,
COMSAT has reserved the right to amend or terminate the Plans according to the
terms of the Plans and with respect to any Plan that has been amended or
terminated within the five year period preceding the date of this Agreement,
such amendment or termination was permitted by the terms of the Plan.
 
   Section 4.10 Intellectual Property; Year 2000.
 
   (a) To the knowledge of COMSAT, COMSAT and its Subsidiaries do not now and
have not in the past used Intellectual Property in the conduct of their
respective businesses which conflicts with or infringes upon any proprietary
rights of others except where such conflict or infringement, individually or in
the aggregate, would not reasonably be expected to have a Material Adverse
Effect on COMSAT. For purposes of this Agreement, the term "Intellectual
Property" means trademarks, trade names, service marks, service names, mark
registrations, logos, assumed names, copyright registrations, patents and all
applications therefor and all other similar proprietary rights.
 
   (b) As described in Section 4.10(b) of the COMSAT Disclosure Schedule,
COMSAT has implemented a program that is designed to ensure that prior to
December 31, 1999, all of the computer software programs, databases and
compilations, computer firmware, computer hardware (whether general or special
purpose), and
 
                                      I-15
<PAGE>
 
other similar or related items of automated, computerized, and/or software
system(s) that are to be used or relied on by COMSAT or any of its Subsidiaries
in the conduct of their respective businesses will not malfunction, will not
cease to function, will not generate incorrect data, and will not provide
incorrect results when processing, providing, and/or receiving date-related
data into and between the twentieth and twenty-first centuries. The program
includes consideration of the status of the major vendors and suppliers of
COMSAT and its Subsidiaries and of the trustees of employee benefit plans as
defined in ERISA Section 3(3) maintained or sponsored by COMSAT or its
Subsidiaries with respect to this issue.
 
   Section 4.11 Certain Contracts and Arrangements.
 
   (a) COMSAT has delivered or otherwise made available (or will make
available) to Lockheed Martin true, correct and complete copies of all
contracts and agreements (and all amendments, modifications and supplements
thereto and all side letters to which COMSAT is a party affecting the
obligations of any party thereunder) to which COMSAT or any of its Subsidiaries
is a party or by which any of their Assets are bound that are material to the
business or Assets of COMSAT and its Subsidiaries taken as a whole, including,
without limitation, all: (i) employment, consulting, non-competition,
severance, golden parachute or indemnification contracts with past or present
directors, officers or employees (including, without limitation, any contract
to which COMSAT is a party involving employees of COMSAT); (ii) contracts
granting a right of first refusal or first negotiation; (iii) partnership or
joint venture agreements; (iv) agreements for the acquisition, sale or lease of
material Assets of COMSAT (by merger, purchase or sale of Assets or stock or
otherwise); (v) contracts or agreements with any Governmental Authority or
INTELSAT or Inmarsat; (vi) contracts or arrangements limiting or restraining
COMSAT, any of COMSAT's Subsidiaries or any successor thereto from engaging or
competing in any business; and (vii) all commitments and agreements to enter
into any of the foregoing (collectively, the "COMSAT Contracts").
 
   (b) Except as set forth in Section 4.11(b) of the COMSAT Disclosure
Schedule:
 
     (i) to the knowledge of COMSAT, there is no default under any COMSAT
  Contract either by COMSAT or any of its Subsidiaries or, by any other party
  thereto, and no event has occurred that with the lapse of time or the
  giving of notice or both would constitute a default thereunder by COMSAT or
  any of its Subsidiaries or, to the knowledge of COMSAT, any other party,
  except for defaults or events that, either individually or in the
  aggregate, would not reasonably be expected to have a Material Adverse
  Effect on COMSAT; and
 
     (ii) no party to any such COMSAT Contract has given notice to COMSAT of
  or made a claim against COMSAT with respect to any breach or default
  thereunder, except for defaults or breaches that, either individually or in
  the aggregate, would not reasonably be expected to have a Material Adverse
  Effect on COMSAT.
 
   (c) Section 4.11(c) of the COMSAT Disclosure Schedule sets forth a list of
each material contract to which COMSAT or any of its Subsidiaries is a party or
may be bound and under the terms of which any of the rights or obligations of
COMSAT or its Subsidiaries will be modified or altered (including, without
limitation, any acceleration of rights or obligations thereunder pursuant to
the terms of any such contract, agreement or arrangement) as a result of the
transactions contemplated by this Agreement.
 
   Section 4.12 Taxes. Except as otherwise disclosed in Section 4.12 of the
COMSAT Disclosure Schedule and except for those matters which, either
individually or in the aggregate, would not reasonably be expected to result in
a Material Adverse Effect on COMSAT:
 
     (a) COMSAT and each of its Subsidiaries have filed (or have had filed on
  their behalf) all Tax Returns required by applicable Law to be filed by any
  of them;
 
     (b) COMSAT and each of its Subsidiaries have paid (or have had paid on
  their behalf) all Taxes due, and have established (or have had established
  on their behalf and for their sole benefit and recourse) an adequate
  accrual (in accordance with GAAP) for the payment of all other Taxes;
 
                                      I-16
<PAGE>
 
     (c) there are no Liens for any Taxes upon the Assets of COMSAT or any of
  its Subsidiaries, other than statutory Liens for Taxes not yet due and
  payable and Liens for real estate Taxes being contested in good faith;
 
     (d) no Audit is pending with respect to any Taxes due from COMSAT or any
  Subsidiary. There are no outstanding waivers extending the statutory period
  of limitation relating to the payment of Taxes due from COMSAT or any
  Subsidiary for any taxable period ending prior to the expiration of the
  Offer which are expected to be outstanding as of the expiration of the
  Offer;
 
     (e) neither COMSAT nor any of its Subsidiaries is a party to, is bound
  by, or has any obligation under, a Tax sharing contract or other agreement
  or arrangement for the allocation, apportionment, sharing, indemnification,
  or payment of Taxes;
 
     (f) neither COMSAT nor any of its Subsidiaries has made an election
  under Section 341(f) of the Code;
 
     (g) the statute of limitations for all Tax Returns of COMSAT and each of
  its Subsidiaries for all years through 1993 have expired for all federal,
  California, Maryland and Connecticut Tax purposes, or such Tax Returns have
  been subject to a final Audit;
 
     (h) neither COMSAT nor any of its Subsidiaries has received any written
  notice of deficiency, assessment or adjustment from the IRS or any other
  Governmental Authority responsible for the administration of any Taxes that
  has not been fully paid or finally settled, and any such deficiency,
  adjustment or assessment shown on such schedule is being contested in good
  faith through appropriate proceedings and adequate reserves have been
  established on COMSAT's financial statements therefor. To the knowledge of
  COMSAT, there are no indications of any other deficiencies, assessments or
  adjustments with respect to COMSAT or any of its Subsidiaries; and
 
     (i) neither COMSAT nor any of its Subsidiaries is a party to any
  agreement, contract or other arrangement that would result, separately or
  in the aggregate, in the requirement to pay any "excess parachute payments"
  within the meaning of Section 280G of the Code or any gross-up in
  connection with such an agreement, contract or arrangement.
 
     (j) For purposes of this Agreement, capitalized terms have the following
  meaning:
 
       (i) "Audit" means any audit, assessment or other examination of
    Taxes or Tax Returns by the IRS or any other Governmental Authority
    responsible for the administration of any Taxes, proceeding or appeal
    of such proceeding relating to Taxes.
 
       (ii) "Taxes" means all federal, state, local and foreign taxes, and
    other assessments of a similar nature (whether imposed directly or
    through withholding) including, but not limited to income, excise,
    property, sales, use (or any similar taxes), gains, transfer,
    franchise, payroll, value-added, withholding, Social Security, business
    license fees, customs, duties and other taxes, assessments, charges, or
    other fees imposed by a Governmental Authority, including any interest,
    additions to tax, or penalties applicable thereto.
 
       (iii) "Tax Returns" shall mean all federal, state, local and foreign
    tax returns, declarations, statements, reports, schedules, forms and
    information returns and any amended Tax Return relating to Taxes.
 
   Section 4.13 Governmental Authorizations. Each of COMSAT and its
Subsidiaries is in possession of all licenses, permits, franchises,
certificates, consents, approvals and other authorizations from appropriate
Governmental Authorities (including the FCC) necessary for COMSAT or any of its
Subsidiaries to own, lease and operate its properties or to carry on their
respective businesses as they are now being conducted ("Governmental
Authorizations"), and all such Governmental Authorizations are valid and in
full force and effect, except where the failure to have any of the Governmental
Authorizations, either individually or in the aggregate, would not reasonably
be expected to have a Material Adverse Effect on COMSAT. No suspension
 
                                      I-17
<PAGE>
 
or termination of any material Governmental Authorization is pending or, to the
knowledge of COMSAT, threatened, except for suspensions or terminations which,
either individually or in the aggregate, would not reasonably be expected to
have a Material Adverse Effect on COMSAT and except as set forth in Section
4.13 of the COMSAT Disclosure Schedule. Neither COMSAT nor any of its
Subsidiaries is in conflict with, or in default or violation of, any material
Governmental Authorization except for conflicts, defaults, or violations which,
either individually or in the aggregate, would not reasonably be expected to
have a Material Adverse Effect on COMSAT.
 
   Section 4.14 Environmental Matters. Except as set forth in Section 4.14 of
the COMSAT Disclosure Schedule, COMSAT and each of its Subsidiaries are in
material compliance with all applicable federal, state and local Laws relating
to pollution or protection of human health or the environment (including,
without limitation, ambient air, surface water, ground water, land surface or
subsurface strata) (collectively, "Environmental Laws"), except for instances
of noncompliance that, either individually or in the aggregate, would not
reasonably be expected to have a Material Adverse Effect on COMSAT. Such
compliance includes, but is not limited to, the possession by COMSAT and its
Subsidiaries of all material permits and other Governmental Authorizations
required under applicable Environmental Laws, and compliance with the terms and
conditions thereof. Except as set forth in Section 4.14 of the COMSAT
Disclosure Schedule, neither COMSAT nor any of its Subsidiaries has received
written notice of, or to the knowledge of COMSAT, is the subject of, any
actions, causes of action, claims, investigations, demands or notices by any
Person alleging liability under or noncompliance with any Environmental Law
("Environmental Claims") that, either individually or in the aggregate, would
reasonably be expected to have a Material Adverse Effect on COMSAT. To the
knowledge of COMSAT, there are no circumstances that are reasonably likely to
prevent or interfere with such material compliance in the future.
 
   Section 4.15 Brokerage Fees and Commissions. Except for Donaldson, Lufkin &
Jenrette Securities Corporation, no Person is entitled to receive from COMSAT
or any of its Subsidiaries any investment banking, brokerage or finder's fee or
fees for financial consulting or advisory services in connection with this
Agreement or any of the transactions contemplated hereby.
 
                                   ARTICLE V
 
     REPRESENTATIONS AND WARRANTIES OF LOCKHEED MARTIN AND ACQUISITION SUB
 
   Lockheed Martin and Acquisition Sub represent and warrant to COMSAT as
follows:
 
   Section 5.1 Organization. Each of Lockheed Martin, Acquisition Sub and Offer
Subsidiary is a corporation or limited liability company, as the case may be,
duly organized, validly existing and in good standing under the Laws of the
jurisdiction of its incorporation or formation, as the case may be, and has all
requisite corporate or limited liability company power and authority, as the
case may be, to own, lease and operate its properties and to carry on its
business as now being conducted, except where the failure to be so organized,
existing and in good standing or to have such power and authority would not, in
the aggregate, reasonably be expected to have a Material Adverse Effect on
Lockheed Martin.
 
   Section 5.2 Authority. Each of Lockheed Martin, Acquisition Sub and Offer
Subsidiary has full corporate or limited liability company power and authority,
as the case may be, to execute and deliver each Transaction Agreement to which
it is a party and to consummate the transactions contemplated thereby. The
execution and delivery of each such Transaction Agreement and the consummation
of the transactions contemplated thereby have been duly and validly authorized
by the Boards of Directors of Lockheed Martin or Acquisition Sub, as the case
may be, and by Lockheed Martin as the sole member of Offer Subsidiary and the
sole stockholder of Acquisition Sub; and no other corporate or limited
liability company proceedings on the part of Lockheed Martin, Acquisition Sub
or Offer Subsidiary, as the case may be, are necessary to authorize any such
Transaction Agreement or to consummate the transactions contemplated thereby.
This Agreement and
 
                                      I-18
<PAGE>
 
each such other Transaction Agreement has been duly and validly executed and
delivered by Lockheed Martin, Acquisition Sub or Offer Subsidiary, as the case
may be, and constitutes the valid and binding agreement of Lockheed Martin,
Acquisition Sub or Offer Subsidiary, as the case may be, (and assuming due and
valid authorization, execution and delivery thereof by the other parties
thereto) enforceable against Lockheed Martin, Acquisition Sub or Offer
Subsidiary, as the case may be, in accordance with its terms, except to the
extent that enforcement thereof may be limited by bankruptcy, insolvency,
reorganization, moratorium, fraudulent conveyance or other similar Laws, now or
hereafter in effect, relating to creditors' rights generally and general
principles of equity (regardless of whether enforceability is considered in a
proceeding at law or in equity).
 
   Section 5.3 Consents and Approvals; No Violations. Except for any applicable
requirements of the Securities Act, the Exchange Act, Antitrust Laws, the
Communications Act, the Satellite Act, the NYSE, the filing and recordation of
articles and/or a certificate of merger with respect to the Merger as required
by the DCBCA and the DGCL, respectively, any filings required by the Investment
Canada Act, such filings and approvals as may be required under the "takeover"
or "blue sky" Laws of various states, or as contemplated by Section 6.19 hereof
or otherwise by this Agreement, neither the execution and delivery of this
Agreement or the Carrier Acquisition Agreement by Lockheed Martin, Acquisition
Sub or Offer Subsidiary, as the case may be, nor the consummation by Lockheed
Martin, Acquisition Sub or Offer Subsidiary, as the case may be, of any
transaction contemplated hereby and thereby will (i) conflict with or result in
any breach of any provision of the charter or by-laws of Lockheed Martin or
Acquisition Sub, or the limited liability company agreement or certificate of
formation of Offer Subsidiary, as the case may be, (ii) require on the part of
Lockheed Martin, Acquisition Sub or Offer Subsidiary any filing with, or the
obtaining of any permit, authorization, consent or approval of, any
Governmental Authority or any other Person, (iii) result in a violation or
breach of, or constitute (with or without due notice or lapse of time or both)
a default (or give rise to any right of termination, amendment, cancellation,
acceleration or payment, or to the creation of a Lien) under any of the terms,
conditions or provisions of any note, mortgage, indenture, other evidence of
indebtedness, guarantee, license, agreement or other contract, instrument or
obligation to which Lockheed Martin or any of its Subsidiaries is a party or by
which any of them or any of their Assets may be bound, or (iv) violate any Law
applicable to Lockheed Martin or any of its Subsidiaries or any of their
Assets, except for such requirements, defaults, rights or violations under
clauses (ii), (iii) and (iv) above that would not reasonably be expected to
have a Material Adverse Effect on Lockheed Martin.
 
   Section 5.4 Capitalization.
 
   (a) As of the close of business on September 11, 1998, the authorized
capital stock of Lockheed Martin consisted of (i) 1,500,000,000 shares of
Lockheed Martin Common Stock, of which 195,848,551 shares were issued and
outstanding, (ii) 50,000,000 shares of Series Preferred Stock, par value $1.00
per share of which no shares were issued and outstanding ("Lockheed Martin
Series Preferred Stock") and (iii) 20,000,000 shares of Series A preferred
stock, par value $1.00 per share ("Lockheed Martin Preferred Stock"), of which
no shares of any class or series were issued and outstanding. As of the close
of business on September 11, 1998, 12,023,408 shares of Lockheed Martin Common
Stock were issuable upon the exercise of outstanding vested and non-vested
options and other rights to acquire shares of Lockheed Martin Common Stock
("Lockheed Martin Stock Options") granted under any stock option plan, program,
employee stock purchase plan, employment agreement or similar arrangement of
Lockheed Martin or any Subsidiaries, each as amended (the "Lockheed Martin
Stock Plans").
 
   (b) All outstanding shares of capital stock of Lockheed Martin are, and all
shares of Lockheed Martin Common Stock issuable pursuant to this Agreement when
issued, will be, duly authorized, validly issued, fully paid and nonassessable
and are not subject to preemptive rights.
 
   (c) Except with respect to the outstanding shares of Lockheed Martin Common
Stock and the Lockheed Martin Stock Options, there are no outstanding bonds,
debentures, notes or other indebtedness or other securities of Lockheed Martin
having the right to vote (or convertible into, or exchangeable for, securities
having the right to vote) on any matters on which shareholders of Lockheed
Martin may vote.
 
 
                                      I-19
<PAGE>
 
   (d) Except with respect to the Lockheed Martin Stock Options, there are no
outstanding securities, options, warrants, calls, rights, commitments,
agreements, arrangements or undertakings of any kind to which Lockheed Martin
or any of its Subsidiaries is a party or by which any them is bound obligating
Lockheed Martin or any of its Subsidiaries to issue, deliver or sell, or cause
to be issued, delivered or sold, additional shares of capital stock or other
Equity Securities of Lockheed Martin or any of its Subsidiaries or obligating
Lockheed Martin or any of its Subsidiaries to issue, grant, extend or enter
into any such security, option, warrant, call, right, commitment, agreement,
arrangement or undertaking.
 
   Section 5.5 Absence of Certain Changes. Except (i) as set forth in Lockheed
Martin's Annual Report on Form 10-K for the year ended December 31, 1997 (the
"Lockheed Martin Form 10-K"), Lockheed Martin's Quarterly Reports on Form 10-Q
for the three month periods ended March 31, 1998 and June 30, 1998,
respectively, or any other document filed prior to the date hereof pursuant to
Section 13(a) or 15(d) of the Exchange Act, or (ii) as contemplated by this
Agreement, from June 30, 1998 until the date hereof, neither Lockheed Martin
nor any of its Subsidiaries has suffered any changes that, either individually
or in the aggregate, would reasonably be expected to have a Material Adverse
Effect on Lockheed Martin.
 
   Section 5.6 Reports. For the purposes of this Agreement, the "Lockheed
Martin SEC Documents" means each registration statement, report, proxy
statement or information statement of Lockheed Martin prepared by it since
January 1, 1996, in the form (including exhibits and any amendments thereto)
filed with the SEC. As of the respective filing dates, the Lockheed Martin SEC
Documents (i) complied as to form in all material respects with the applicable
requirements of the Securities Act and the Exchange Act and (ii) did not
contain any untrue statement of a material fact or omit to state a material
fact required to be stated therein or necessary to make the statements made
therein, in the light of the circumstances under which they were made, not
misleading. Each of the consolidated balance sheets included in or incorporated
by reference into the Lockheed Martin SEC Documents (including the related
notes and schedules) fairly presents the consolidated financial position of
Lockheed Martin and its Subsidiaries as of its date, and each of the
consolidated statements of income, retained earnings and cash flows included in
or incorporated by reference into the Lockheed Martin SEC Documents (including
any related notes and schedules) fairly presents the results of operations,
retained earnings or cash flows, as the case may be, of Lockheed Martin and its
Subsidiaries for the periods set forth therein (subject, in the case of
unaudited statements, to normal year-end audit adjustments which would not be
material in amount or effect), in each case in accordance with GAAP
consistently applied during the periods involved, except as may be noted
therein. None of Lockheed Martin and its Subsidiaries has any Liabilities
required to be disclosed in a balance sheet of Lockheed Martin or in the notes
thereto prepared in accordance with GAAP consistently applied except (a)
Liabilities reflected on, or reserved against in, a balance sheet of Lockheed
Martin or in the notes thereto, and included in the Lockheed Martin SEC
Documents and (b) Liabilities incurred since June 30, 1998 in the ordinary
course of business.
 
   Section 5.7 Opinion of Financial Advisor. Bear, Stearns & Co. Inc. has
delivered to the Board of Directors of Lockheed Martin its opinion that, as of
the date hereof, the terms of this Agreement are fair to the holders of
Lockheed Martin Common Stock from a financial point of view.
 
   Section 5.8 Brokers. Except for Bear, Stearns & Co. Inc., no Person is
entitled to receive from Lockheed Martin or any of its Subsidiaries any
investment banking, brokerage or finder's fee or fees for financial consulting
or advisory services in connection with this Agreement or the transactions
contemplated hereby.
 
                                   ARTICLE VI
 
                                   COVENANTS
 
   Section 6.1 Conduct of Business of COMSAT. Except (i) as contemplated by
this Agreement, (ii) as set forth in Section 6.1A of the COMSAT Disclosure
Schedule, or (iii) as otherwise permitted by Sections 6.1(a)-(q) of this
Agreement, during the period from the date of this Agreement to the Effective
Time, unless
 
                                      I-20
<PAGE>
 
Lockheed Martin has consented thereto in writing (which consent shall not be
unreasonably withheld or delayed), COMSAT shall, and shall cause each of its
Subsidiaries to, (x) conduct its operations in the ordinary course, (y) use
commercially reasonable efforts to preserve intact its business organization
and goodwill and maintain satisfactory relationships with those Persons having
business relationships with them, and (z) use commercially reasonable efforts
to keep available the services of its officers and employees. Without limiting
the generality of and in addition to the foregoing, and except as otherwise
contemplated by this Agreement or as set forth in Section 6.1A of the COMSAT
Disclosure Schedule, prior to the time specified in the preceding sentence,
unless Lockheed Martin has consented thereto in writing (which consent shall
not be unreasonably withheld or delayed), COMSAT and its Subsidiaries:
 
     (a) except as required to give effect to changes in Law, shall not amend
  their respective articles of incorporation or by-laws or other comparable
  governing instruments in a manner that would adversely affect the
  consummation of the transactions contemplated by, or otherwise adversely
  affect the rights of Lockheed Martin or its Subsidiaries under, any
  Transaction Agreement;
 
     (b) except as set forth in Section 6.1(b) of the COMSAT Disclosure
  Schedule, shall not, and shall not permit any of its Subsidiaries to, issue
  any shares of their capital stock or Equity Securities (except by COMSAT as
  permitted by this Agreement, in connection with the COMSAT Stock Options
  that are outstanding on the date of this Agreement or which may hereafter
  be granted as permitted by this Agreement under COMSAT Stock Plans or
  shares of COMSAT Common Stock pursuant to nondiscretionary grants under the
  current terms of any existing Plan), or grant, confer or award any options,
  appreciation rights, warrants, conversion rights, restricted stock, stock
  units, performance shares or other rights, not existing on the date hereof,
  with respect to any shares of its capital stock or other Equity Securities
  of COMSAT or its Subsidiaries except that, during the twelve-month period
  beginning upon the date hereof and ending on the first anniversary hereof
  and during each subsequent twelve-month period ending upon subsequent
  anniversaries hereof, COMSAT may grant COMSAT Stock Options to acquire up
  to the number of shares of COMSAT Common Stock as is equal to 1.5% of the
  number of issued and outstanding shares of COMSAT Common Stock as of the
  end of the preceding fiscal year pursuant to the continued operation of the
  COMSAT Stock Plans, and up to 200,000 shares of COMSAT Common Stock during
  each calendar year beginning after the date of this Agreement pursuant to
  the continued operation of the COMSAT Employee Stock Purchase Plan, all in
  the ordinary course of business and consistent with past practice, or
  effect any stock split or otherwise change its capitalization;
 
     (c) except as set forth in Section 6.1(c) of the COMSAT Disclosure
  Schedule, shall not, and shall not permit any of its Subsidiaries to, (i)
  declare, set aside or pay any dividend or make any other distribution or
  payment with respect to any shares of its capital stock or other ownership
  interests (other than regular quarterly cash dividends not to exceed $0.05
  per share of COMSAT Common Stock and dividends and distributions from
  Subsidiaries of COMSAT to COMSAT or another of its Subsidiaries) or (ii)
  directly or indirectly redeem, purchase or otherwise acquire any shares of
  its capital stock or capital stock of any of its Subsidiaries, or make any
  commitment for any such action;
 
     (d) shall not pledge or otherwise encumber shares of capital stock of
  COMSAT or any of its Subsidiaries;
 
     (e) except (i) as disclosed in Section 6.1(e) of the COMSAT Disclosure
  Schedule, (ii) as required by Law (including any amendment required to
  maintain the qualification of any Plan intended to be "qualified" under
  Section 401(a) of the Code) or (iii) as contemplated by this Agreement,
  shall not (A) except in the ordinary course of business and consistent with
  past practice, enter into or amend any employment or similar agreements or
  arrangements with any of its directors or executive officers, (B) amend or
  otherwise change the terms of the Plans in any manner which would
  constitute a material change in Plan design or materially increase the cost
  of a Plan, including, without limitation, amend any employment, severance
  or similar agreements or arrangements in existence on the date hereof, (C)
  adopt any new Plans, programs or arrangements or any severance or similar
  agreements or arrangements, or (D) except in the ordinary course of
  business and consistent with past practice, increase any compensation,
  bonus or other benefits payable to any current or former director or
  executive officer;
 
                                      I-21
<PAGE>
 
     (f) except as set forth in Section 6.1(f) of the COMSAT Disclosure
  Schedule, shall not transfer, sell, lease, license or dispose of any
  material lines of business, Subsidiaries, divisions, operating units or
  facilities (other than facilities currently closed or currently proposed to
  be closed) outside the ordinary course of business or enter into any
  material commitment or transaction outside the ordinary course of business;
 
     (g) except as set forth in Section 6.1(g) of the COMSAT Disclosure
  Schedule, shall not, and shall not permit any of its Subsidiaries to,
  authorize, propose or announce an intention to authorize or propose to
  another Person, or enter into an agreement with respect to, any merger,
  consolidation or business combination, any acquisition of Assets or Equity
  Securities (other than the purchase of Assets in the ordinary course of
  business), any disposition of Assets or Equity Securities (other than the
  disposition of Assets or Equity Securities in the ordinary course of
  business) or any release or relinquishment of any contract rights in which,
  in any such case, the aggregate consideration is in excess of $5 million
  for any individual transaction or $20 million for all of such transactions
  in any one year period or which would materially adversely affect the
  ability of COMSAT or any of its Subsidiaries to consummate any of the
  transactions contemplated by this Agreement. For purposes of this Section
  6.1(g), Section 6.1(i), Section 6.1(j)(ii) and Section 6.1(l) only, any
  actions taken by COMSAT to preserve substantially (or to increase or
  decrease such interest by no more than 2.0% in any fiscal year) its
  existing ownership interest in INTELSAT or Inmarsat in connection with (A)
  annual share redeterminations and adjustments or (B) pursuant to capital
  calls approved by the governing bodies of INTELSAT or Inmarsat in
  accordance with their charter documents, shall be deemed to be in the
  ordinary course of COMSAT's business;
 
     (h) except as set forth in Section 6.1(h) of the COMSAT Disclosure
  Schedule, shall not make any material Tax election other than in the
  ordinary course of business and consistent with past practice, or settle or
  compromise any Tax Liability in excess of $3 million arising from or in
  connection with any single issue;
 
     (i) shall not make or agree to make any capital expenditures other than
  (i) expenditures in the ordinary course of business, (ii) capital
  expenditures that are consistent with COMSAT's strategic business plans
  (the "COMSAT Business Plans") and (iii) additional capital expenditures not
  in excess of $5 million;
 
     (j) except as set forth in Section 6.1(j) of the COMSAT Disclosure
  Schedule, except in the ordinary course of business and except as
  consistent with the COMSAT Business Plans, shall not, and shall not permit
  any of its Subsidiaries to, (i) incur, create, assume or otherwise become
  liable for borrowed money or assume, guarantee, endorse or otherwise become
  responsible or liable for the obligations of any other Person (other than
  COMSAT and its Subsidiaries) in excess of $5 million per occurrence and $20
  million in the aggregate or (ii) make any loans or advances to any other
  Person (other than COMSAT and its Subsidiaries) in excess of $5 million per
  occurrence and $20 million in the aggregate;
 
     (k) except as set forth in Section 6.1(k) of the COMSAT Disclosure
  Schedule, or as required by Law or GAAP, shall not effect any material
  change in any of its methods of accounting in effect as of December 31,
  1997;
 
     (l) except as provided in the Shareholders Agreement, shall not impose
  limitations not already in existence on the date hereof, not imposed on
  other shareholders of COMSAT, on the enjoyment by any of Lockheed Martin
  and its Subsidiaries of the legal rights generally enjoyed by shareholders
  of COMSAT;
 
     (m) except as set forth in Section 6.1(m) of the COMSAT Disclosure
  Schedule, shall not pay, discharge or satisfy any material Liabilities,
  other than the payment, discharge or satisfaction of any such Liability (i)
  reflected or reserved against in, or contemplated by, the financial
  statements (or the notes thereto) of COMSAT and its Subsidiaries, (ii)
  incurred in the ordinary course of business or (iii) which is legally
  required to be paid, discharged or satisfied;
 
                                      I-22
<PAGE>
 
     (n) shall not adopt a plan of complete or partial liquidation,
  dissolution, merger, consolidation, restructuring, recapitalization or
  other material reorganization of COMSAT or any plan of merger or
  consolidation of any of its Subsidiaries in which such Subsidiary is not
  the surviving entity;
 
     (o) shall not, and shall not permit any of its Subsidiaries to take any
  action which would make any representation or warranty of COMSAT contained
  herein untrue or incorrect in any material respect as of the Effective
  Time;
 
     (p) shall not fail to take reasonable efforts to cause the Merger to
  constitute a reorganization within the meaning of Section 368(a) of the
  Code; and
 
     (q) shall not enter into a legally binding commitment with respect to,
  or any agreement to take, any of the foregoing actions.
 
   Section 6.2 INTELSAT and Inmarsat Privatizations. Any actions taken pursuant
to U.S. Government instruction and any actions taken in good faith by COMSAT or
its Subsidiaries in connection with the planned privatizations of INTELSAT or
Inmarsat shall not be considered a breach of the first sentence of Section 6.1
hereof or, to the extent applicable, of subsections 6.1(f), (g), (h), (i), (j),
(k) or (m) discharge of liabilities. Notwithstanding the foregoing, other than
as provided in Section 6.1A of the COMSAT Disclosure Schedule or pursuant to
the Existing INTELSAT Documents, the Existing Inmarsat Documents, the Inmarsat
Restructuring Documents or the New Skies Documents, COMSAT shall not:
 
     (a) sell, transfer, assign or dispose of or agree to sell, transfer,
  assign or dispose of the INTELSAT Interests or the Inmarsat Interests
  (including, without limitation, by entering into any options with respect
  thereto);
 
     (b) enter into any voting rights, proxy or other agreement with respect
  to the voting of any of the INTELSAT Interests or the Inmarsat Interests
  that would be binding on Lockheed Martin, COMSAT or their respective
  Subsidiaries following the Merger;
 
     (c) enter into any lock-up, standstill or other similar agreement (a
  "Lock-Up Agreement") with respect to the INTELSAT Interests or the Inmarsat
  Interests that would be binding on Lockheed Martin, COMSAT or their
  respective Subsidiaries following the Merger; provided that COMSAT or its
  Subsidiaries may enter into a Lock-Up Agreement in connection with an
  initial public offering by INTELSAT, Inmarsat or New Skies Satellites,
  N.V., on terms that are usual and customary to those entered into by
  directors, affiliates or significant shareholders in similar transactions;
  or
 
     (d) take any other action or omit to take any action (including by way
  of votes in the INTELSAT Board of Governors or Meeting of Signatories, or
  the Inmarsat Council, in either case except to the extent instructed to the
  contrary by the United States Government, pursuant to the Satellite Act)
  which would reasonably be expected to materially impair the economic value
  of or any of the rights associated with the INTELSAT Interests or the
  Inmarsat Interests; provided, that COMSAT shall not be required to force a
  vote to be held on a matter in any of the foregoing bodies where consistent
  with past practice such decision would be decided by consensus rather than
  a vote.
 
     (e) For purposes of this Agreement, capitalized terms have the following
  meaning:
 
       (i) "ICO" shall mean ICO Global Communications (Holdings) Limited.
 
       (ii) "Inmarsat Convention" shall mean the Convention on the
    International Maritime Satellite Organization (Inmarsat) which entered
    into force on July 16, 1979, last amended by amendments thereto which
    entered into force on June 26, 1997.
 
       (iii) "Inmarsat Existing Documents" shall mean the Inmarsat
    Convention, the Operating Agreement on Inmarsat which entered into
    force on July 16, 1979, as last amended by amendments thereto which
    entered into force on June 26, 1997, the Headquarters Agreement Between
    Inmarsat and the government of the United Kingdom, Great Britain and
    Northern Ireland which entered into force on February 25, 1980, and all
    existing policies and procedures approved by the Inmarsat Council
    pursuant to the foregoing.
 
                                      I-23
<PAGE>
 
       (iv) "Inmarsat Interests" shall mean the Inmarsat Investment Share
    owned by COMSAT (or all of the shares of Inmarsat PLC received by
    COMSAT in lieu thereof pursuant to the Inmarsat Privatization) and all
    rights and obligations associated therewith, including, prior to the
    Inmarsat Privatization, COMSAT's rights as an Inmarsat Signatory (as
    defined in the Inmarsat Convention).
 
       (v) "Inmarsat Investment Share" shall mean an investment share
    described in the Inmarsat Operating Agreement.
 
       (vi) "Inmarsat Privatization" shall mean the restructuring of
    Inmarsat contemplated by the Inmarsat Restructuring Documents.
 
       (vii) "Inmarsat Restructuring Documents" shall mean, in each case
    substantially in the form of the draft made available by the General
    Counsel to the Inmarsat parties as of August 26, 1998, the Master
    Transition Agreement, to be entered into between Inmarsat and Inmarsat
    PLC, together with (a) the following documents that are defined in such
    Master Transition Agreement: the Business Transfer Agreement, the LESO
    Agreement, the License Agreement, the New Memorandum and Articles of
    Association, the Public Services Agreement, the Shareholders' Agreement
    and the Trust Deeds and (b) the Memoranda and Articles of Association
    of Inmarsat One Limited, Inmarsat Two Company, Inmarsat Three Limited
    and Inmarsat Limited and each as subsequently amended in accordance
    with the decisions of the Inmarsat Council.
 
       (viii) "INTELSAT Existing Documents" shall mean the Agreement
    Relating to the International Telecommunications Satellite Organization
    (INTELSAT) (the "INTELSAT Agreement") which entered into force on
    February 12, 1973, the Operating Agreement Relating to the
    International Telecommunications Satellite Organization (INTELSAT) (the
    "INTELSAT Operating Agreement") which entered into force on February
    12, 1973, and the Headquarters Agreement between the Government of the
    United States of America and INTELSAT which entered into force on
    November 24, 1976, and all existing policies and procedures approved by
    the INTELSAT Board of Governors pursuant to the foregoing.
 
       (ix) "INTELSAT Interests" shall mean the INTELSAT Investment Share
    owned by COMSAT, any ownership or other interests received by COMSAT
    relating to any entity created pursuant to any partial or full
    privatization of INTELSAT (including New Skies Satellites, N.V.), any
    ownership or other interests received by COMSAT relating to any other
    entity created pursuant to the full or partial privatization of
    INTELSAT, and in each case all rights and obligations associated
    therewith, including, prior to the full privatization of INTELSAT,
    COMSAT's rights as an INTELSAT Signatory (as defined in the INTELSAT
    Agreement).
 
       (x) "INTELSAT Investment Share" shall mean an investment share
    described in the INTELSAT Operating Agreement.
 
       (xi) "New Skies Documents" shall mean, in each case, in
    substantially the same form of the draft contained in the Report of the
    New INTELSAT 2000 Working Part to the Twenty-Second Assembly of
    Parties, AP-22-7E S/3/98, 24 February 1998; the Draft Trust Agreement,
    the Ensured Capacity Rights (ECR) Contract, the Draft Satellite
    Operational Services Contract, the Draft Transition Services Agreement,
    the Draft INC Subscription Agreement, the INC Articles of Association,
    the Leaseback Equalization Arrangements/Transponder Leasing Agreement,
    along with the Record of Decisions of the Twenty-Second (Extraordinary)
    Meeting of the INTELSAT Assembly of Parties, AP-22-3E FINAL S/3/98, 30-
    31 March 1998 and each as subsequently amended in accordance with the
    decisions of the INTELSAT Assembly of Parties.
 
   Section 6.3 Conduct of Business of Lockheed Martin. Except as otherwise
contemplated by this Agreement, during the period from the date of this
Agreement to the Effective Time, unless COMSAT has consented thereto in writing
(which consent shall not be unreasonably withheld or delayed), Lockheed Martin
shall not and shall cause each of its Subsidiaries not to:
 
     (a) adopt a plan of complete or partial liquidation, dissolution,
  merger, consolidation, restructuring, recapitalization or other material
  reorganization of Lockheed Martin;
 
                                      I-24
<PAGE>
 
     (b) take any action which would make any representation or warranty of
  Lockheed Martin contained herein untrue or incorrect as of the Effective
  Time;
 
     (c) fail to take reasonable efforts to cause the Merger to constitute a
  reorganization within the meaning of Section 368(a) of the Code; and
 
     (d) enter into a legally binding commitment with respect to, or any
  agreement to take, any of the foregoing actions.
 
   Section 6.4 No Solicitation.
 
   (a) COMSAT shall, and shall cause its Subsidiaries and their respective
officers, directors, employees, consultants, investment bankers, accountants,
attorneys and other advisors, representatives and agents (collectively, "COMSAT
Representatives") to immediately cease any discussions or negotiations with any
Person that may be ongoing with respect to any Acquisition Proposal (as defined
below). COMSAT shall not, nor shall it permit any of its Subsidiaries to, nor
shall it authorize or permit any COMSAT Representative to, directly or
indirectly, (i) solicit or initiate, or knowingly encourage the submission of,
any Acquisition Proposal or (ii) participate in any discussions or negotiations
regarding, or furnish to any Person (other than Lockheed Martin or its
representatives or affiliates) any information, that may reasonably be expected
to lead to, an Acquisition Proposal; provided, however, that if, prior to the
COMSAT Shareholders Meeting, the Board of Directors of COMSAT determines in
good faith, based upon advice of independent counsel, that it is necessary to
do so in order to comply with its fiduciary duties to COMSAT's shareholders
under applicable Law, the Board of Directors of COMSAT may permit COMSAT in
response to an Acquisition Proposal that was not solicited by COMSAT or its
officers, directors or employees (x) to furnish information (including any non-
public information) with respect to COMSAT (including its Subsidiaries) and
afford access to its properties, books and records pursuant to a
confidentiality agreement designed to reasonably protect the confidentiality of
such information, and (y) to participate in discussions or negotiations
regarding such Acquisition Proposal. For purposes of this Agreement, the term
"Acquisition Proposal" means any proposal or offer from any Person (other than
Lockheed Martin or its representatives or affiliates) to acquire, directly or
indirectly, in one or more transactions, Assets (including, without limitation,
the capital stock of Subsidiaries) of COMSAT or any of its Subsidiaries having
an aggregate value equal to more than 10% of the market capitalization of
COMSAT, any tender offer or exchange offer that if consummated would result in
any Person beneficially owning more than 10% of any class of Equity Securities
of COMSAT, any merger, consolidation, business combination, sale of all or
substantially all the Assets, recapitalization, liquidation, dissolution or
similar transaction involving COMSAT, other than the transactions contemplated
by this Agreement; provided that no transaction specified in Section 6.1A of
the COMSAT Disclosure Schedule shall be deemed to be an Acquisition Proposal.
 
   (b) Except as set forth in this Section 6.4, neither the Board of Directors
of COMSAT nor any committee thereof shall (i) withdraw, modify or materially
qualify (or publicly propose to withdraw, modify or materially qualify) its
approval or recommendation of the Offer, the Merger or this Agreement, (ii)
approve or recommend, or publicly propose to approve or recommend, any
Acquisition Proposal or (iii) enter, or publicly propose to enter, into any
agreement with respect to any Acquisition Proposal. Notwithstanding the
foregoing, in the event that, prior to the COMSAT Shareholders Meeting, the
Board of Directors of COMSAT determines in good faith, based upon advice of
independent counsel, that it is necessary to do so in order to comply with its
fiduciary duties to COMSAT's shareholders under applicable Law, the Board of
Directors of COMSAT may terminate this Agreement pursuant to Section 7.1(d)(ii)
hereof solely in order to concurrently enter into a definitive agreement to
effect a Superior Proposal. For purposes of this Agreement, the term "Superior
Proposal" means any bona fide proposal or offer from one or more Persons (other
than Lockheed Martin and its affiliates) to acquire, directly or indirectly, in
one or more transactions for consideration consisting of cash and/or
securities, more than 50% of the shares of COMSAT Common Stock then outstanding
or all or substantially all the Assets of COMSAT and its Subsidiaries taken as
a whole, and otherwise on terms which the Board of Directors of COMSAT
determines in its good faith judgment (based on the advice of a financial
advisor of nationally recognized reputation) to be more favorable to the
holders of COMSAT Common Stock
 
                                      I-25
<PAGE>
 
than are the Offer and the Merger and for which financing, to the extent
required, is then committed or which, in the good faith judgment of the Board
of Directors of COMSAT (based on the advice of a financial advisor of
nationally recognized reputation), is reasonably capable of being financed by
such Person.
 
   (c) In addition to the obligations of COMSAT set forth in paragraphs (a) and
(b) of this Section 6.4, COMSAT shall promptly advise Lockheed Martin orally
and in writing of COMSAT's receipt of any Acquisition Proposal, any request for
information or an inquiry that could lead to or is otherwise related to any
Acquisition Proposal, the identity of the Person making such request or
Acquisition Proposal and the material terms of any such Acquisition Proposal.
COMSAT shall keep Lockheed Martin fully informed of the status and terms
(including amendments) of any such request or Acquisition Proposal, unless the
Board of Directors determines in good faith, based upon advice of independent
counsel, that it is necessary not to do so in order to comply with its
fiduciary duties to COMSAT's shareholders under applicable Law.
 
   (d) Nothing contained in this Section 6.4 shall prohibit COMSAT from taking
and disclosing to its shareholders a position contemplated by Rule 14e-2(a)
promulgated under the Exchange Act or issuing a communication meeting the
requirements of Rule 14d-9(e) promulgated under the Exchange Act; provided,
however, neither COMSAT nor its Board of Directors nor any committee thereof
shall, except as permitted by Section 6.4(b) hereof, withdraw, modify or
materially qualify, or publicly propose to withdraw, modify or materially
qualify, its position with respect to the Offer, the Merger or this Agreement
or to approve or recommend, or publicly propose to approve or recommend, an
Acquisition Proposal.
 
   Section 6.5 Preparation of Proxy Statement; COMSAT Shareholders Meeting.
 
   (a) As promptly as practicable following the date hereof, Lockheed Martin
shall, in cooperation with COMSAT, prepare and file with the SEC preliminary
proxy materials which shall constitute the Proxy Statement/Prospectus in
connection with the Merger (such proxy statement/prospectus, and any amendments
or supplements thereto, the "Proxy Statement/Prospectus") and a registration
statement on Form S-4 with respect to the issuance of Lockheed Martin Common
Stock in the Merger (the "Form S-4"), together with any other materials
required to be filed with the SEC in connection with the Merger. The
ProxyStatement/Prospectus will be included inthe Form S-4 as Lockheed Martin's
prospectus. The Form S-4 and the Proxy Statement/Prospectus shall comply as to
form in all material respects with the applicable provisions of the Securities
Act and the Exchange Act. Each of Lockheed Martin and COMSAT shall use all
reasonable efforts to have the Form S-4 cleared by the SEC as promptly as
practicable after filing with the SEC and to keep the Form S-4 effective as
long as is necessary to consummate the Merger. Lockheed Martin shall, as
promptly as practicable after receipt thereof, provide copies of any written
comments received from the SEC with respect to the Proxy Statement/Prospectus
to COMSAT and advise COMSAT of any oral comments with respect to the Proxy
Statement/Prospectus received from the SEC. None of the information supplied or
to be supplied by Lockheed Martin in writing specifically for inclusion or
incorporation by reference in the Proxy Statement/Prospectus and each amendment
or supplement thereto, at the time of mailing thereof and at the time of the
COMSAT Shareholders Meeting, will contain an untrue statement of a material
fact or omit to state a material fact required to be stated therein or
necessary to make the statements therein, in light of the circumstances under
which they were made, not misleading. None of the information supplied or to be
supplied by COMSAT in writing specifically for inclusion or incorporation by
reference in the Proxy Statement/Prospectus and each amendment or supplement
thereto, at the time of mailing thereof and at the time of the COMSAT
Shareholders Meeting, will contain an untrue statement of a material fact or
omit to state a material fact required to be stated therein or necessary to
make the statements therein, in light of the circumstances under which they
were made, not misleading. Lockheed Martin shall advise COMSAT in writing,
promptly after it receives notice thereof, of the time when the Form S-4 has
become effective or any supplement or amendment thereto has been filed, the
issuance of any stop order, the suspension of the qualification of the Lockheed
Martin Common Stock issuable in connection with the Merger for offering or sale
in any jurisdiction, or any request by the SEC for amendment of the Proxy
Statement/Prospectus or the Form S-4 or comments thereon and responses thereto
or requests by the SEC for additional information. Lockheed Martin shall
provide COMSAT with a reasonable opportunity to review and comment on any
 
                                      I-26
<PAGE>
 
amendment or supplement to the Proxy Statement/Prospectus prior to filing such
with the SEC, and shall provide COMSAT with a copy of all such filings made
with the SEC. No amendment or supplement to the information supplied by COMSAT
for inclusion in the Proxy Statement/Prospectus shall be made without the
approval of COMSAT, which approval shall not be unreasonably withheld or
delayed.
 
   (b) Subject to Sections 6.4 and 7.1(d)(ii) hereof, COMSAT shall, at such
time as determined by Lockheed Martin after consultation with COMSAT, duly
call, give notice of, convene, hold, postpone, adjourn and reconvene a meeting
or meetings of its shareholders (the "COMSAT Shareholders Meeting") for the
purpose of considering and taking action with respect to the Merger and this
Agreement, shall take reasonable efforts to solicit the adoption of this
Agreement by its shareholders (including, but not limited to, employing the
services of a proxy solicitation firm), and the Board of Directors of COMSAT
shall recommend adoption of the Merger and this Agreement by the shareholders
of COMSAT. Without limiting the generality of the foregoing but subject to its
rights pursuant to Sections 6.4 and 7.1(d)(ii) hereof, the obligations of
COMSAT to duly call, give notice of, convene, hold, postpone, adjourn and
reconvene the COMSAT Shareholders Meeting pursuant to the first sentence of
this Section 6.5(b) shall not be affected by the commencement, public proposal,
public disclosure or communication to COMSAT of any Acquisition Proposal.
 
   Section 6.6 Access to Information.
 
   (a) Between the date of this Agreement and the Effective Time, upon
reasonable notice and at reasonable times, and subject to any access,
disclosure, copying or other limitations imposed by applicable Law or any of
the contracts of COMSAT and its Subsidiaries, COMSAT shall give Lockheed
Martin, Acquisition Sub and their authorized representatives reasonable access
to all offices and other facilities and to all books and records of it and its
Subsidiaries and to employees of COMSAT and its Subsidiaries, and will permit
Lockheed Martin, Acquisition Sub or their authorized representatives, as the
case may be, to make such inspections as it or they may reasonably require, and
shall cause its officers and those of its Subsidiaries to furnish Lockheed
Martin, Acquisition Sub and their authorized representatives with such
financial and operating data and other information with respect to any of
COMSAT and its Subsidiaries as Lockheed Martin, Acquisition Sub or their
authorized representatives, as the case may be, may from time to time
reasonably request; provided that to the extent that access, disclosure or
copying of any of the foregoing is limited by applicable Law or contract,
COMSAT shall take reasonable efforts to provide a summary of such information
to Lockheed Martin within the limits of applicable Law or contract. Lockheed
Martin, Acquisition Sub and their authorized representatives shall conduct all
such inspections in a manner which shall minimize any disruptions of the
business and operations of COMSAT and its Subsidiaries.
 
   (b) Lockheed Martin, Acquisition Sub and COMSAT agree that each of the
Confidentiality Agreements (as hereinafter defined), other than Sections 3 and
7 thereof, shall remain binding and in full force and effect.
 
   Section 6.7 Reasonable Efforts. Subject to the terms and conditions of this
Agreement, each of the parties hereto agrees to use all reasonable efforts to
take, or cause to be taken, all actions, and to do, or cause to be done, all
things reasonably necessary, proper or advisable under applicable Law to
consummate and make effective the transactions contemplated by this Agreement
(including, without limitation, (i) cooperating in the preparation and filing
of the Offer Documents, the Schedule 14D-9, the Proxy Statement/Prospectus, the
Form S-4 and any amendments to any thereof, (ii) taking of all action
reasonably necessary, proper or advisable to secure any necessary consents or
waivers under existing debt obligations of COMSAT and its Subsidiaries or amend
the notes, indentures or agreements relating thereto to the extent required by
such notes, indentures or agreements or redeem or repurchase such debt
obligations, (iii) contesting any pending legal proceeding relating to any
transaction contemplated by this Agreement and (iv) executing any additional
instruments necessary to consummate the transactions contemplated hereby). In
case at any time after the Effective Time any further action is necessary to
carry out the purposes of this Agreement or the Carrier Acquisition Agreement,
the proper officers and directors of each party hereto shall use all reasonable
efforts to take all such necessary action.
 
                                      I-27
<PAGE>
 
   Section 6.8 Listing Application. Lockheed Martin shall prepare and submit to
the NYSE a listing application covering the shares of Lockheed Martin Common
Stock issuable in the Merger and shall use commercially reasonable efforts to
obtain, prior to the Effective Time, approval for the listing of such Lockheed
Martin Common Stock, subject to official notice of issuance.
 
   Section 6.9 Consents and Approvals.
 
   (a) In furtherance of and not in limitation of the agreements of the parties
contained in Section 6.7 hereof, the parties shall each cooperate and use its
respective reasonable efforts to promptly seek the amendment or repeal of the
Satellite Act and other applicable Laws, including any regulations of the FCC
or other Governmental Authority, or the applicable provisions thereof, that
would prohibit or limit the ability of Lockheed Martin to (x) acquire and own
all of the Equity Securities of COMSAT, (y) appoint all of the officers and
directors of COMSAT following the Merger, or (z) consummate the transactions
contemplated by this Agreement.
 
   (b) In furtherance of and not in limitation of the agreements of the parties
contained in Section 6.7 hereof, the parties shall each cooperate and use its
respective reasonable efforts to promptly make all filings and obtain all
consents and approvals of Governmental Authorities (including, without
limitation, the FCC) and other Persons necessary to consummate the transactions
contemplated by this Agreement including, without limitation, to permit
Lockheed Martin and Offer Subsidiary to consummate the Carrier Acquisition, to
cause Offer Subsidiary to become an Authorized Carrier and to consummate the
Offer and the Merger. Each of the parties hereto will furnish to the other
parties such necessary information and reasonable assistance as such other
Persons may reasonably request in connection with the foregoing.
 
   (c) In furtherance of and not in limitation of the agreements of the parties
contained in Section 6.7 hereof, the parties shall each (i) take promptly all
actions necessary to make the filings required of such party or any of their
affiliates under the applicable Antitrust Laws, (ii) comply at the earliest
practicable date with any request for additional information or documentary
material received by such party or any of their affiliates from the Federal
Trade Commission or the Antitrust Division of the Department of Justice
pursuant to the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as
amended (the "HSR Act") or other Governmental Authority pursuant to Antitrust
Laws, and (iii) cooperate with the other parties hereto in connection with any
filings under applicable Antitrust Laws and in connection with resolving any
investigation or other inquiry concerning any transaction contemplated by this
Agreement commenced by any of the Federal Trade Commission, the Antitrust
Division of the Department of Justice, state attorneys general, or other
Governmental Authorities. For purposes of this Agreement, the term "Antitrust
Laws" means the Sherman Act, as amended, the Clayton Act, as amended, the HSR
Act, the Federal Trade Commission Act, as amended, EC Merger Regulations and
all other federal, state and foreign Laws that are designed or intended to
prohibit, restrict or regulate actions having the purpose or effect of
monopolization or restraint of trade. For purposes of this Agreement, "EC
Merger Regulations" mean Council Regulation (EEC) No. 4064/89 of December 21,
1989 on the Control of Concentrations Between Undertakings, OJ (1989) L 395/1
and the regulations and decisions of the Council or Commission of the European
Community (the "CCEC") or other organs of the European Union or European
Community implementing such regulations.
 
   (d) In furtherance of and not in limitation of the agreements of the parties
contained in Section 6.7 hereof the parties shall each use all reasonable
efforts to resolve such objections, if any, as may be asserted under any
Antitrust Law or any other applicable Law, with respect to any transaction
contemplated by this Agreement. If any administrative, judicial or legislative
action or proceeding is initiated (or threatened to be initiated) or any other
action is taken by any Person challenging any transaction contemplated by this
Agreement as violative of any Antitrust Law or any other applicable Law, the
parties shall each cooperate to contest and resist any such action or
proceeding, and to have vacated, lifted, reversed or overturned any decree,
judgment, injunction, ruling, decision, finding or other order (whether
temporary, preliminary or permanent) (any such decree, judgment, injunction,
ruling, decision, finding or other order is hereafter referred to as an
"Order") or other official action or decision of any Governmental Authority
that is in effect and that restricts, prevents or
 
                                      I-28
<PAGE>
 
prohibits consummation of any transaction contemplated by this Agreement,
including, without limitation, by pursuing all reasonable avenues of
administrative and judicial appeal.
 
   (e) Notwithstanding anything in this Agreement to the contrary:
 
       (i) In no event shall any of Lockheed Martin and its Subsidiaries be
  required to agree to hold separate or to divest any of their respective
  businesses or Assets, or agree to any other restriction or condition with
  respect to the acquisition or ownership of any of their respective
  businesses or Assets or the conduct or operation of any of their respective
  businesses or Assets, or following the consummation of the Offer or the
  Effective Time, of COMSAT or any of its Subsidiaries, as may be required
  (i) by any applicable Governmental Authority (including, without
  limitation, the Federal Trade Commission, the Antitrust Division of the
  Department of Justice or any state attorney general) in order to resolve
  such objections as such Governmental Authority may have to such
  transactions under any Antitrust Law, or (ii) by any domestic or foreign
  court or other tribunal, in any action or proceeding brought by any Person
  challenging such transactions as violative of any Antitrust Law, in order
  to avoid the entry of, or to effect the dissolution, vacating, lifting,
  altering or reversal of, any Order that has the effect of restricting,
  preventing or prohibiting the consummation of any transaction contemplated
  by this Agreement, if the Board of Directors of Lockheed Martin determines
  in good faith that any such agreement to hold separate or to divest or
  agreement to other restriction or condition is not in the best interests of
  Lockheed Martin.
 
       (ii) Except for seeking review by the full FCC of any FCC staff
  decision denying any application to permit Lockheed Martin or Offer
  Subsidiary to consummate the Carrier Acquisition, to cause Offer Subsidiary
  to become an Authorized Carrier or to consummate the Offer, Lockheed Martin
  shall not be required to undertake or continue any contest or resistance of
  an action or proceeding or take any other action, in each case of the type
  referred to in Section 6.7 hereof (including, but not limited to, Section
  6.7(iii) hereof) or Section 6.9 hereof (including, but not limited to,
  Section 6.9(d) hereof) if, after taking into account advice of independent
  counsel with respect to relevant matters, including, without limitation,
  the likely outcome of the action or proceeding, the timing thereof and the
  likely costs related thereto, the Board of Directors of Lockheed Martin
  determines in good faith that undertaking or continuing any such contest or
  resistance or taking any such other action is not in the best interests of
  Lockheed Martin.
 
   (f) Each of COMSAT, Lockheed Martin and Acquisition Sub shall promptly
inform the other parties of any material communication received by such party
from the Federal Trade Commission, the Antitrust Division of the Department of
Justice, the FCC or any other Governmental Authority or INTELSAT or Inmarsat
regarding any transaction contemplated by this Agreement, along with copies of
any written communications received with respect thereto and written summaries
of any oral communications with respect thereto.
 
   Section 6.10 Public Announcements. The initial press release relating to
this Agreement shall be a joint press release and thereafter COMSAT, Lockheed
Martin and Acquisition Sub shall consult with each other before issuing any
press release or otherwise making any public statements with respect to any
transaction contemplated by this Agreement and shall not issue any such press
release or make any such public statement prior to such consultation, except as
may be required by Law or by obligations pursuant to any listing agreement with
any securities exchange; provided that the statements included in any such
press release or the public statement made in compliance with this Section 6.10
may be published, reiterated or restated, in whole or in part, without the
necessity of further complying with this Section 6.10.
 
   Section 6.11 Notification. COMSAT shall give prompt notice to Lockheed
Martin and Lockheed Martin shall give prompt notice to COMSAT, in each case,
after it has actually become aware, of (i) any representation or warranty made
by it contained in this Agreement that is qualified as to materiality becoming
untrue or inaccurate in any respect or any such representation or warranty that
is not so qualified becoming untrue or inaccurate in any material respect or
(ii) the failure by it to comply with or satisfy in any material respect any
covenant, condition or agreement to be complied with or satisfied by it under
this Agreement; provided, however, that no such notification shall affect the
representations, warranties, covenants or agreements of the parties or the
conditions to the obligations of the parties under this Agreement.
 
                                      I-29
<PAGE>
 
   Section 6.12 Certain Litigation. The parties shall cooperate in the defense
of any litigation commenced after the date hereof against either party or any
of their respective directors by any shareholder of COMSAT or Lockheed Martin
relating to any transaction contemplated by this Agreement and shall not settle
any such litigation without the prior written consent of the other party. In
addition, subject to its rights under Section 6.4 hereof, COMSAT shall not
voluntarily cooperate with any other Person that may hereafter seek to restrain
or prohibit or otherwise oppose any transaction contemplated by this Agreement
and shall cooperate with Lockheed Martin and Acquisition Sub to resist any such
effort to restrain or prohibit or otherwise oppose such transaction.
 
   Section 6.13 Employee and Benefit Matters; Stock Options and Awards.
 
   (a) Stock Options and Awards. Except as provided in Section 6.13(b) hereof,
as of the Effective Time, Lockheed Martin shall assume all COMSAT Stock Plans
and the COMSAT Stock Options. Each COMSAT Stock Option outstanding at the
Effective Time shall be deemed to constitute an option to acquire, on the same
terms and conditions, mutatis mutandis, as were applicable under such COMSAT
Stock Option prior to the Effective Time, (i) the number of shares of Lockheed
Martin Common Stock as the holder of such COMSAT Stock Option would have been
entitled to receive pursuant to the Merger had such holder exercised such
COMSAT Stock Option in full immediately prior to the Effective Time (not taking
into account whether or not such option was in fact then exercisable), (ii) at
a price per share equal to (x) the aggregate exercise price for COMSAT Common
Stock otherwise purchasable pursuant to such COMSAT Stock Option divided by (y)
the number of shares of Lockheed Martin Common Stock deemed purchasable
pursuant to such assumed COMSAT Stock Option, provided that the number of
shares of Lockheed Martin Common Stock that may be purchased upon exercise of
any such Lockheed Martin Stock Option shall not include any fractional share
and, upon exercise of any such Lockheed Martin Stock Option, a cash payment
shall be made for any fractional share based on the last sale price per share
of Lockheed Martin Common Stock on the trading day immediately preceding the
date of exercise. COMSAT shall use its reasonable efforts to provide, on or
prior to the Effective Time, a written acknowledgement of each holder of a
COMSAT Stock Option that such COMSAT Stock Option from and after the Effective
Time will be exercisable for shares of Lockheed Martin Common Stock as provided
herein, provided that COMSAT need not do so if Lockheed Martin determines to
its reasonable satisfaction that the terms of such COMSAT Stock Option or
COMSAT Stock Plan provides that, after giving effect to any permitted action by
the COMSAT board of directors or committee thereof, from and after the
Effective Time, such COMSAT Stock Option shall be exercisable only for shares
of Lockheed Martin Common Stock and not for shares of common stock of the
Surviving Corporation or any other Person. COMSAT shall amend each other Plan,
agreement or arrangement that provides benefits or payments by reference to the
price of COMSAT Common Stock, other than the COMSAT Stock Option Plans, to
provide that as of and after the Effective Time, the payments or benefits shall
be measured by reference to the price of Lockheed Martin Common Stock,
determined in like manner to the adjustments prescribed above with respect to
the exercise price of COMSAT Stock Options and the number of shares of COMSAT
Common Stock into which COMSAT Stock Options are exercisable. In respect of
each COMSAT Stock Option to be converted into options or rights to acquire
Lockheed Martin Common Stock, Lockheed Martin shall file as soon as practicable
after the Effective Time with the SEC, and keep current the effectiveness of, a
registration statement on Form S-8 or other appropriate form for as long as
such options or rights remain outstanding (and maintain the current status of
the prospectus with respect thereto). Lockheed Martin agrees to reserve for
issuance a number of shares of Lockheed Martin Common Stock equal to the number
of shares of Lockheed Martin Common Stock issuable under the COMSAT Stock
Options.
 
   (b) Employee Stock Purchase Plan. COMSAT shall terminate each employee stock
purchase plan COMSAT maintains for its or any of its Subsidiaries' employees no
later than the Effective Time.
 
   (c) Change in Control. COMSAT shall cause to be amended each of the Plans
listed in Section 6.13(c) of the COMSAT Disclosure Schedule and/or the Board of
Directors of COMSAT shall adopt a resolution to provide that (i) for purposes
of the Plans listed in Section 6.13(c)(1) of the COMSAT Disclosure Schedule,
neither the execution of this Agreement, the consummation of the transactions
contemplated by this Agreement
 
                                      I-30
<PAGE>
 
nor approval of this Agreement or the transactions contemplated hereby by the
Board of Directors or shareholders of COMSAT shall be a "Change in Control" of
COMSAT (or any similar triggering event resulting in the acceleration or other
change in the terms of benefits payable under the Plans); and (ii) for the
purposes of the Plans listed in Section 6.13(c)(2) of the COMSAT Disclosure
Schedule, a "Change in Control" of COMSAT (or any similar triggering event
resulting in the acceleration or other change in the terms of benefits payable
under the Plans) shall occur at the Effective Time.
 
   (d) Service Credit. Following the Effective Time, Lockheed Martin shall, or
shall cause the Surviving Corporation, to recognize the service of current or
former employees of COMSAT and any of its Subsidiaries (the "COMSAT Employees")
for purposes of participation, eligibility and vesting under any benefit Plan
(including eligibility for benefit levels under any severance, retiree medical
or vacation pay plans to the extent based on length of service) in which such
employees may then be eligible to participate, except to the extent that such
service was not taken into account under the comparable Plan immediately prior
to the Effective Time. A COMSAT Employee who has accrued but unused vacation
time under a Plan at the Effective Time shall retain such accrued but unused
vacation after the Effective Time.
 
   (e) Pre-Existing Condition Limitations; Deductibles. With respect to any
Plans of Lockheed Martin in which the COMSAT Employees participate effective as
of the Effective Time, Lockheed Martin shall, or shall cause the Surviving
Corporation to: (i) not impose any requirements under the Plans more onerous
than those currently in effect with respect to pre-existing condition
limitations or exclusions and waiting periods with respect to eligibility and
participation applicable to COMSAT Employees, and (ii) recognize credit toward
satisfying any applicable co-payment, deductible expense requirement, out-of-
pocket expense limit and maximum lifetime benefit limits of each COMSAT
Employee or their eligible dependents as and to the extent any payment would
have been previously recognized under the applicable COMSAT welfare benefit
Plans prior to the Effective Time.
 
   (f) Assumption of Plans. As of the Effective Time, Lockheed Martin shall
assume and shall cause the Surviving Corporation to assume in accordance with
their terms all Plans and agreements listed in Section 6.13(f) of the COMSAT
Disclosure Schedule.
 
   (g) Benefit Continuation. For a period of at least one year following the
Effective Time, Lockheed Martin shall, or shall cause the Surviving Corporation
to, provide each COMSAT Employee with qualified plan and employee welfare plan
benefits (other than plans provided exclusively to management) which are
comparable in the aggregate to the qualified plan and welfare plan benefits
(other than plans provided exclusively to management) provided to such COMSAT
Employee immediately prior to the Effective Time.
 
   Section 6.14 No Restrictions. COMSAT shall not intentionally take any
action, or omit to take any action, if the result of such action or omission
could reasonably be expected to result in any restriction or limitation on the
ability of Lockheed Martin or its Subsidiaries to vote any of the Shares
purchased by any of Lockheed Martin and its Subsidiaries in the Offer.
 
   Section 6.15 Advice of Changes. COMSAT shall cause its senior officers to
use reasonable efforts to promptly advise Lockheed Martin of any change or
occurrence that would reasonably be expected to have a Material Adverse Effect
on COMSAT and, to the extent permitted by Law, to meet from time to time with
Lockheed Martin's senior officers to discuss COMSAT's business.
 
   Section 6.16 Indemnification.
 
   (a) From and after the Effective Time, Lockheed Martin shall cause the
Surviving Corporation to indemnify, defend and hold harmless the present and
former officers, directors, employees and agents of COMSAT and its Subsidiaries
(the "Indemnified Parties") against all losses, claims, damages, expenses or
liabilities arising out of or related to actions or omissions or alleged
actions or omissions occurring at or prior to the Effective Time to the same
extent and on the same terms and conditions (including with respect to
advancement of expenses) provided for in COMSAT's Articles of Incorporation and
By-Laws and agreements
 
                                      I-31
<PAGE>
 
in effect on the date hereof (to the extent consistent with applicable Law as
of the Effective Time), which provisions will survive the Merger and continue
in full force and effect after the Effective Time, in each case consistent with
Applicable Law. Without limiting the foregoing, (i) Lockheed Martin shall, and
shall cause the Surviving Corporation to, periodically advance expenses
(including attorneys' fees) as incurred by an Indemnified Party with respect to
the foregoing to the extent required under COMSAT's Articles of Incorporation
and Bylaws in effect on the date hereof (to the extent consistent with
applicable Law) and (ii) any determination required to be made with respect to
whether an Indemnified Party shall be entitled to indemnification shall, if
requested by such Indemnified Party, be made by independent legal counsel
selected by the Surviving Corporation and reasonably satisfactory to such
Indemnified Party. Lockheed Martin hereby guarantees the obligation of the
Surviving Corporation provided for under this Section 6.16(a).
 
   (b) For a period of six years after the Effective Time, Lockheed Martin
shall use reasonable efforts to cause to be maintained in effect the current
policies of directors and officers liability insurance maintained by COMSAT
(provided that Lockheed Martin may substitute therefor policies with reputable
and financially sound carriers of at least the same coverage and amounts
containing terms and conditions which are no less advantageous in the
aggregate) with respect to claims arising from or related to facts or events
which occurred at or before the Effective Time; provided, that Lockheed Martin
shall not be obligated to make annual premium payments for such insurance to
the extent such premiums exceed 150% of the annual premiums paid as of the date
hereof by COMSAT for such insurance (the "Maximum Amount"). If the amount of
the annual premiums necessary to maintain or procure such insurance coverage
exceeds the Maximum Amount, Lockheed Martin and the Surviving Corporation shall
maintain the most advantageous policies of directors, and officers' insurance
obtainable for an annual premium equal to the Maximum Amount.
 
   (c) The provisions of this Section 6.16 are intended to be for the benefit
of, and shall be enforceable by, each Indemnified Party, his or her heirs and
his or her representatives.
 
   Section 6.17 No Control. Prior to the Effective Time, Lockheed Martin shall
not and shall not permit any of its Subsidiaries to, directly or indirectly,
control, supervise or direct, or attempt to control, supervise or direct, the
operations of COMSAT or of any common carrier activities or licensed facilities
authorized by the FCC, in contravention of applicable Law; those operations,
including complete control and supervision of common carrier activities, FCC-
licensed facilities, employees and policies shall be the sole responsibility of
COMSAT and its Subsidiaries.
 
   Section 6.18 Accountant's Letters. Each of COMSAT and Lockheed Martin shall
use all reasonable efforts to cause to be delivered to the other party two
letters from its independent public accountants, one dated the date on which
the Form S-4 shall become effective and one dated the Closing Date, each
addressed to COMSAT and Lockheed Martin, in form and substance reasonably
satisfactory to the other party and customary in scope and substance for
comfort letters delivered by independent public accountants in connection with
registration statements similar to the Form S-4.
 
   Section 6.19 North American Numbering Plan. COMSAT acknowledges that an
affiliate of Lockheed Martin is party to a contract pursuant to which it acts
as administrator of the North American Numbering Plan. Lockheed Martin shall
take such actions as are necessary so that the existence of the aforementioned
contract does not prevent or delay consummation of the Offer or the Merger.
 
   Section 6.20 Affiliate Letters. On or prior to the date of the COMSAT
Shareholders Meeting, COMSAT will deliver to Lockheed Martin a letter
identifying all Persons who may be deemed to be "affiliates" of COMSAT for
purposes of Rule 145 under the Securities Act as of the date of the COMSAT
Shareholders Meeting (the "COMSAT Affiliate Letter"). On or prior to the
Closing Date, COMSAT will use all reasonable efforts to cause each Person
identified as an "affiliate" in the COMSAT Affiliate Letter to deliver a
written agreement acknowledging the restrictions on affiliates under Rule 145
under the Securities Act.
 
 
                                      I-32
<PAGE>
 
                                  ARTICLE VII
 
                         TERMINATION; AMENDMENT; WAIVER
 
   Section 7.1 Termination. This Agreement may be terminated and the Offer and
the Merger may be abandoned at any time (notwithstanding approval of the Merger
by the shareholders of COMSAT) prior to the Effective Time:
 
   (a) by mutual written consent of COMSAT and Lockheed Martin;
 
   (b) by COMSAT or Lockheed Martin if any court of competent jurisdiction in
the United States of America or other United States Governmental Authority
shall have issued a final Order or taken any other final action restraining,
enjoining or otherwise prohibiting the consummation of the Offer or the Merger
and such Order or other action is or shall have become nonappealable;
 
   (c) by Lockheed Martin if, due to an occurrence or circumstance which would
result in a failure to satisfy any of the conditions set forth in Exhibit A
hereto, Lockheed Martin shall have (i) failed to commence the Offer within the
time required by Regulation 14D under the Exchange Act, (ii) terminated the
Offer without the purchase of any Shares thereunder or (iii) failed to accept
for payment and pay for Shares pursuant to the Offer prior to the one year
anniversary of the date hereof; provided that Lockheed Martin may not terminate
pursuant to this Section 7.1(c) if Lockheed Martin is in material breach of
this Agreement;
 
   (d) by COMSAT if (i) there shall not have occurred a material breach of any
representation, warranty, covenant or agreement of COMSAT or any of its
Subsidiaries contained in this Agreement and Lockheed Martin shall have (A)
failed to commence the Offer within the time required by Regulation 14D under
the Exchange Act, (B) terminated the Offer without the purchase of any Shares
thereunder or (C) failed to accept for payment and pay for Shares pursuant to
the Offer on or prior to the one year anniversary of the date hereof or (ii)
prior to the purchase of Shares pursuant to the Offer, the Board of Directors
of COMSAT or any committee thereof shall have (A) determined that an
Acquisition Proposal is a Superior Proposal, and approved a definitive
agreement to effect such Superior Proposal and directed the authorized officers
of COMSAT to execute and deliver such definitive agreement concurrently with
the effectiveness of the termination of this Agreement pursuant to this Section
7.1(d)(ii) or (B) adopted any resolution to effect any of the foregoing;
provided, that such termination under this clause (ii) shall not be effective
until payment of the fee required by Section 7.3(a) hereof;
 
   (e) by Lockheed Martin prior to the purchase of Shares pursuant to the
Offer, if (i) there shall have occurred a breach of any representation or
warranty of COMSAT or its Subsidiaries contained in this Agreement that would
reasonably be expected to have a Material Adverse Effect on COMSAT or would
reasonably be expected to materially adversely affect (or materially delay) the
consummation of the Offer, (ii) there shall have occurred a breach of any
covenant or agreement of COMSAT or its Subsidiaries contained in this Agreement
that has or would reasonably be expected to have a Material Adverse Effect on
COMSAT or that would reasonably be expected to materially adversely affect (or
materially delay) the consummation of the Offer, which shall not have been
cured prior to the earlier of (A) 10 days following notice of such breach and
(B) two business days prior to the date on which the Offer expires, (iii) the
Board of Directors of COMSAT or any committee thereof shall have (A) determined
that an Acquisition Proposal is a Superior Proposal, (B) withdrawn, modified or
materially qualified (including by amendment of the Schedule 14D-9) in a manner
adverse to Lockheed Martin or Acquisition Sub its approval or recommendation of
the Offer, the Merger or this Agreement, (C) recommended to COMSAT's
shareholders another Acquisition Proposal, (D) adopted any resolution to effect
any of the foregoing, or (iv) the Minimum Condition shall not have been
satisfied upon the expiration of the Offer and at or prior to such time a
Person or group (other than Lockheed Martin or Acquisition Sub) shall have
commenced, publicly proposed or publicly disclosed an Acquisition Proposal;
 
                                      I-33
<PAGE>
 
   (f) by COMSAT prior to the purchase of Shares pursuant to the Offer, if (i)
there shall have occurred a breach of any representation or warranty of
Lockheed Martin or Acquisition Sub contained in this Agreement that would
reasonably be expected to materially adversely affect (or materially delay) the
consummation of the Offer or (ii) there shall have occurred a material breach
of any covenant or agreement of Lockheed Martin or Acquisition Sub contained in
this Agreement that would reasonably be expected to materially adversely affect
(or materially delay) the consummation of the Offer which shall not have been
cured prior to the earlier of (A) 10 days following notice of such breach and
(B) two business days prior to the date on which the Offer expires;
 
   (g) by Lockheed Martin or COMSAT if the shareholders of COMSAT shall not
have approved the Merger and this Agreement at the COMSAT Shareholders Meeting,
including any postponement or adjournment thereof, on or before the one year
anniversary of the date hereof;
 
   (h) by COMSAT or Lockheed Martin if (i) there shall not have occurred a
material breach of any representation, warranty, covenant or agreement of such
party contained in this Agreement and (ii) the Effective Time shall not have
occurred on or before the two year anniversary of the date hereof;
 
   Section 7.2 Effect of Termination. In the event of the termination and
abandonment of this Agreement pursuant to Section 7.1 hereof, this Agreement
shall forthwith become void and have no effect, without any Liability on the
part of any party hereto or its affiliates, directors, officers or
shareholders, other than the provisions of this Section 7.2 and Sections
6.6(b), 7.3, 8.2, 8.11 and 8.12 hereof. Nothing contained in this Section 7.2
shall relieve any party from Liability for any willful breach of this
Agreement.
 
   Section 7.3 Fees and Expenses.
 
   (a) If any of the following shall occur:
 
     (i) COMSAT or Lockheed Martin terminates this Agreement pursuant to
  Section 7.1(e)(iv) or Section 7.1(g) and, within 12 months thereafter,
  COMSAT or any of its Subsidiaries enters into an agreement with respect to
  an Acquisition Proposal, or an Acquisition Proposal is consummated,
  involving any Person or affiliate, or any group in which such Person (or
  any affiliate thereof, or any group in which such Person or affiliate is a
  member) (A) with whom COMSAT or any COMSAT Representative had discussions
  with respect to an Acquisition Proposal, (B) to whom COMSAT or any COMSAT
  Representative furnished information with respect to an Acquisition
  Proposal or (C) who had commenced, publicly proposed or publicly disclosed
  an Acquisition Proposal or expressed to COMSAT an interest in an
  Acquisition Proposal, in the case of each of clauses (A), (B) and (C) after
  the date hereof and prior to such termination; or
 
     (ii) COMSAT terminates this Agreement pursuant to Section 7.1(d)(ii)
  hereof;
 
then, in each case, COMSAT shall pay to Lockheed Martin, within one business
day following the execution and delivery of such agreement or such occurrence,
as the case may be, or simultaneously with such determination pursuant to
Section 7.1(d)(ii) hereof, a fee, in cash, of $75 million (the "Termination
Fee"); provided, that COMSAT in no event shall be obligated to pay more than
one such Termination Fee with respect to all such agreements and occurrences
and such termination.
 
   (b) Except as specifically provided in this Section 7.3(b) or the
Registration Rights Agreement, each party shall bear its own expenses incurred
in connection with the transactions contemplated by the Transaction Agreements,
including, without limitation, out-of-pocket costs, and fees and expenses of
investment bankers, finders, brokers, agents, representatives, counsel and
accountants as well as fees and expenses incident to the negotiation,
preparation and execution of the Transaction Agreements and related
documentation, preparation of filings and consents with Governmental
Authorities and other Persons, and any litigation resulting from the execution
of the Transaction Agreements; provided, that in the event the Termination Fee
becomes payable, COMSAT shall, upon the receipt of documentation in form
reasonably satisfactory to COMSAT, promptly reimburse Lockheed Martin and its
Subsidiaries in cash in immediately available funds, for any of the foregoing
expenses of Lockheed Martin or its Subsidiaries, up to $5.0 million in the
aggregate.
 
                                      I-34
<PAGE>
 
   (c) Notwithstanding anything to the contrary contained in this Agreement,
upon payment by COMSAT in full of the amounts referred to in Sections 7.3(a)
and 7.3(b) hereof, COMSAT shall be released from all Liability hereunder,
including any Liability for any claims by Lockheed Martin, Acquisition Sub or
any of their affiliates based upon or arising out of any breach of this
Agreement.
 
   (d) The agreements contained in this Section 7.3 are an integral part of the
transactions contemplated by this Agreement and constitute liquidated damages
and not a penalty. In the event of any dispute as to whether any fee or other
amount due under this Section 7.3 is due and payable, the prevailing party
shall be entitled to receive from the other party the reasonable costs and
expenses (including reasonable legal fees and expenses) in connection with any
action, including the filing of any lawsuit or other legal action, relating to
such dispute. Interest shall be paid on the amount any unpaid fee at the
publicly announced prime rate of Citibank, N.A. from the date such fee was
required to be paid.
 
   Section 7.4 Amendment. This Agreement may be amended by action taken by
COMSAT, Lockheed Martin and Acquisition Sub at any time before or after
approval of the Merger and this Agreement by the shareholders of COMSAT, if
any; provided that after the date of approval of the Merger and this Agreement
by the shareholders of COMSAT, no amendment shall be made which decreases the
amount or changes the form of the Merger Consideration or which adversely
affects the rights of COMSAT's shareholders hereunder without the approval of
such shareholders. This Agreement may not be amended except by an instrument in
writing signed on behalf of the parties.
 
   Section 7.5 Extension; Waiver. At any time prior to the Effective Time, the
parties may (i) extend the time for the performance of any of the obligations
or other acts of the other parties hereto, (ii) waive any inaccuracies in the
representations and warranties of the other parties contained herein or in any
document, certificate or writing delivered pursuant hereto or (iii) waive
compliance with any of the agreements or conditions of the other parties hereto
contained herein; provided that after the date of approval of the Merger and
this Agreement by the shareholders of COMSAT, no extensions or waivers shall be
made which adversely affect the rights of COMSAT's shareholders hereunder
without the approval of such shareholders. Any agreement on the part of any
party to any such extension or waiver shall be valid only if set forth in an
instrument in writing signed on behalf of such party.
 
                                  ARTICLE VIII
 
                                 MISCELLANEOUS
 
   Section 8.1 Survival. The representations, warranties, covenants and
agreements made herein shall not survive beyond the Effective Time; provided,
that the covenants and agreements contained in Section 6.16 hereof shall
survive beyond the Effective Time without limitation.
 
   Section 8.2 Entire Agreement. Except for the Confidentiality Agreements
dated as of August 5, 1997 between Lockheed Martin and COMSAT (the
"Confidentiality Agreements"), which shall continue in full force and effect
other than Sections 3 and 7 thereof (which are superseded hereby), the
Transaction Agreements (including the schedules and exhibits and the agreements
and other documents referred to therein) embody the entire agreement and
understanding of the parties, and supersede all prior agreements or
understandings, with respect to the subject matters thereof.
 
   Section 8.3 Governing Law. This Agreement shall be governed by and construed
in accordance with the internal laws of the State of Delaware except for
internal corporate matters, which shall be governed by the Laws of the
respective parties' jurisdictions of incorporation.
 
   Section 8.4 Notices. In any case where any notice or other communication is
required or permitted to be given hereunder (including, without limitation, any
change in the information set forth in this Section 8.4), such notice or
communication shall be in writing and (i) personally delivered, (ii) sent by
postage prepaid certified or registered mail, return receipt requested, (iii)
sent by recognized overnight courier, or (iv) transmitted by telecopier, with a
copy sent by postage prepaid certified or registered mail, return receipt
requested, or by recognized overnight courier, as follows:
 
                                      I-35
<PAGE>
 
   (a) If to the Lockheed Martin or Acquisition Sub, to:
 
     Lockheed Martin Corporation
     6801 Rockledge Drive
     Bethesda, Maryland 20817
     Telephone:(301) 897-6000
     Telecopy:(301) 897-6791
     Attention: General Counsel
 
     with a copy to:
 
     O'Melveny & Myers LLP
     555 13th Street, N.W., Suite 500W
     Washington, D.C. 20004-1109
     Telephone:(202) 383-5300
     Telecopy:(202) 383-5414
     Attention: David G. Litt, Esq.
 
   (b) If to COMSAT, to:
 
     COMSAT Corporation
     6560 Rock Spring Drive
     Bethesda, Maryland 20817
     Telephone:(301) 214-3000
     Telecopy:(301) 214-7128
     Attention: General Counsel
 
     with a copy to:
 
     Skadden, Arps, Slate, Meagher & Flom LLP
     919 Third Avenue
     New York, New York 10022
     Telephone:(212) 735-3000
     Telecopy:(212) 735-2000
     Attention: Richard L. Easton, Esq.
 
   Section 8.5 Successors and Assigns; No Third Party Beneficiaries. This
Agreement and all of the provisions hereof shall be binding upon and inure to
the benefit of the parties and their respective successors and permitted
assigns, but neither this Agreement nor any of the rights, interests or
obligations hereunder shall be assigned by any party (whether by operation of
Law or otherwise) without the prior written consent of the other party;
provided, that Lockheed Martin may assign its rights and obligations hereunder
or those of Acquisition Sub to Lockheed Martin or any Subsidiary of Lockheed
Martin, but in each case no such assignment shall relieve Lockheed Martin or
Acquisition Sub, of its obligations hereunder. This Agreement shall be binding
upon and inure solely to the benefit of each party hereto, and except for
Section 6.16 hereof nothing in this Agreement, express or implied, is intended
to or shall confer upon any other Person any rights, benefits or remedies of
any nature whatsoever under or by reason of this Agreement.
 
   Section 8.6 Counterparts. This Agreement may be signed in any number of
counterparts, each of which shall be an original, with the same effect as if
all signatures were on the same instrument.
 
   Section 8.7 Interpretation. Article and section headings in this Agreement
are included for the convenience of reference only and do not constitute a part
of this Agreement for any other purpose. References to parties and articles and
sections in this Agreement are references to the parties to or the articles and
sections of this Agreement, as the case may be, unless the context shall
require otherwise.
 
   Section 8.8 Schedules. The COMSAT Disclosure Schedule shall be construed
with and as an integral part of this Agreement to the same extent as if the
same had been set forth verbatim herein.
 
                                      I-36
<PAGE>
 
   Section 8.9 Legal Enforceability. Any provision of this Agreement that is
prohibited or unenforceable in any jurisdiction shall, as to that jurisdiction,
be ineffective to the extent of the prohibition or unenforceability without
invalidating the remaining provisions of this Agreement or affecting the
validity or enforceability of the provision in any other jurisdiction.
 
   Section 8.10 No Waivers; Remedies; Specific Performance.
 
   (a) No failure or delay by any party in exercising any right, power or
privilege under this Agreement shall operate as a waiver of such right, power
or privilege. A single or partial exercise of any right, power or privilege
shall not preclude any other or further exercise of such right, power or
privilege or the exercise of any other right, power or privilege. The rights
and remedies provided in this Agreement shall be cumulative and not exclusive
of any rights or remedies available at law or in equity.
 
   (b) In view of the uniqueness of the agreements contained in this Agreement
and the transactions contemplated hereby and the fact that each party would not
have an adequate remedy at law for money damages in the event that any
obligation under this Agreement is not performed in accordance with its terms,
each party therefore agrees that the other parties to this Agreement shall be
entitled to specific enforcement of the terms of this Agreement in addition to
any other remedy to which any of them may be entitled, at law or in equity.
 
   Section 8.11 Exclusive Jurisdiction. Each party (i) agrees that any action
with respect to this Agreement or transactions contemplated by this Agreement
shall be brought exclusively in the courts of the State of Delaware or of the
United States of America for the State of Delaware, (ii) accepts for itself and
in respect of its property, generally and unconditionally, the jurisdiction of
those courts, (iii) irrevocably waives any objection, including, without
limitation, any objection to the laying of venue or based on the grounds of
forum non conveniens, which it may now or hereafter have to the bringing of any
action in those jurisdictions; provided, however, that each party may assert in
an action in any other jurisdiction or venue each mandatory defense, third-
party claim or similar claim that, if not so asserted in such action, may not
be asserted in an original action in the courts referred to in clause (i)
above. Lockheed Martin and COMSAT each hereby appoints Corporation Trust
Company as its agent for service of process in the State of Delaware in
connection with any such action.
 
   Section 8.12 Waiver of Jury Trial. Each party waives any right to a trial by
jury in any action to enforce or defend any right under this Agreement or any
amendment, instrument, document or agreement delivered, or which in the future
may be delivered, in connection with this Agreement and agrees that any action
shall be tried before a court and not before a jury.
 
                               ----------------
 
        [The remainder of this page has been left blank intentionally.]
 
                                      I-37
<PAGE>
 
   IN WITNESS WHEREOF, each of the parties has caused this Agreement and Plan
of Merger to be executed on its behalf by its officers thereunto duly
authorized, all as of the day and year first above written.
 
                                          COMSAT CORPORATION
 
                                          By: /s/ Betty C. Alewine
                                             ----------------------------------
                                                Name:Betty C. Alewine
                                                Title:President and
                                                      Chief Executive Officer
 
                                          LOCKHEED MARTIN CORPORATION
 
                                          By: /s/ Vance D. Coffman
                                             ----------------------------------
                                                Name:Vance D. Coffman
                                                Title:Chairman and
                                                      Chief Executive Officer
 
                                          DENEB CORPORATION
 
                                          By: /s/ John V. Sponyoe
                                             ----------------------------------
                                                Name:John V. Sponyoe
                                                Title:Chief Executive Officer
 
                                      I-38
<PAGE>
 
                                                                       EXHIBIT A
 
                            CONDITIONS OF THE OFFER
 
   Notwithstanding any other provision of the Offer, Lockheed Martin shall not
be required to accept for payment or pay for, and may delay the acceptance for
payment of (whether or not any Shares have theretofore been accepted for
payment), or the payment for, any Shares tendered, and may terminate or extend
the Offer and not accept for payment any Shares, if:
 
     (i) immediately prior to the expiration of the Offer (as extended in
  accordance with the terms of the Offer and the Merger Agreement), (A) any
  applicable waiting period under the Antitrust Laws shall not have
  terminated or expired and all consents or approvals required under the
  Antitrust Laws shall not have been received, (B) fewer than one third (1/3)
  of the outstanding shares of COMSAT Common Stock shall have been validly
  tendered and not withdrawn (the "Minimum Condition"), (C) the shareholders
  of COMSAT shall not have approved the Merger and this Agreement pursuant to
  Section 29-367 of the DCBCA, (D) Lockheed Martin and Offer Subsidiary shall
  not have received all approvals of the FCC necessary for them to consummate
  the Carrier Acquisition, (E) the Carrier Acquisition shall not have been
  consummated, (F) Offer Subsidiary shall not have been approved by the FCC
  to be an Authorized Carrier, (G) Offer Subsidiary shall not have been
  authorized by the FCC to acquire the maximum number of shares of COMSAT
  Common Stock to be purchased pursuant to the Offer (the affirmative
  obligations of subsections (D)-(G) shall be referred to as (the "Authorized
  Carrier Conditions"), or (H) Lockheed Martin or its Subsidiaries shall not
  have the right to vote any of the shares without restriction or limitation
  except as expressly set forth in Section 303 of the Satellite Act (47
  U.S.C. (S) 733); or
 
     (ii) on or after the date of the Merger Agreement and prior to the
  acceptance for payment of Shares, any of the following conditions exist:
 
       (a) any of the representations or warranties of COMSAT contained in
    the Merger Agreement shall not have been true and correct at the date
    when made or (except for those representations and warranties made as
    of a particular date which need only be true and correct as of such
    date) shall cease to be true and correct (without giving effect to any
    limitation as to "materiality" or "Material Adverse Effect" set forth
    therein) at any time prior to consummation of the Offer, except for
    changes permitted by the Merger Agreement and except where the failure
    to be so true and correct would not, either individually or in the
    aggregate, reasonably be expected to have a Material Adverse Effect on
    COMSAT; provided, that if any such failure to be so true and correct
    (without giving effect to any limitation as to "materiality" or
    "Material Adverse Effect" set forth therein) is curable by COMSAT
    through the exercise of its reasonable efforts, then Lockheed Martin
    may not terminate the Offer under this subsection (a) until 10 business
    days after written notice thereof has been given to COMSAT by Lockheed
    Martin and unless at such time the matter has not been cured; or
 
       (b) COMSAT shall have breached any of its covenants or agreements
    contained in the Merger Agreement, except for any such breaches that,
    individually or in the aggregate, would not reasonably be expected to
    have a Material Adverse Effect on COMSAT; provided that, if any such
    breach is curable by COMSAT through the exercise of its reasonable
    efforts, then Lockheed Martin may not terminate the Offer under this
    subsection (b) until 10 business days after written notice thereof has
    been given to COMSAT by Lockheed Martin and unless at such time the
    breach has not been cured; or
 
       (c) (A) after the date of the Merger Agreement, there shall have
    been any change in existing Law or any new Law promulgated, enacted,
    enforced or deemed applicable to COMSAT or to the transactions
    contemplated by the Merger Agreement or (B) INTELSAT or Inmarsat shall
    have adopted a plan for privatization, or have been privatized, in
    whole or in part, in a manner or pursuant to terms and conditions (or,
    in the case of an adopted plan, proposed terms and conditions), in the
    case of either clause (A) or clause (B) that Lockheed Martin determines
    in good faith (after
 
                                     I-A-1
<PAGE>
 
    consultation with COMSAT) would reasonably be expected to have a
    Material Adverse Effect on COMSAT; or
 
       (d) any fact or circumstance exists or shall have occurred that has
    or would reasonably be expected to have a Material Adverse Effect on
    COMSAT; or
 
       (e) there shall have occurred (i) any general suspension of trading
    in securities on the NYSE (other than intra-day trading halts), (ii)
    the declaration of a banking moratorium or any suspension of payments
    in respect of banks in the United States of America (whether or not
    mandatory), (iii) the commencement of a war, armed hostilities or other
    international or national calamity directly or indirectly involving the
    United States of America and that would reasonably be expected to have
    a Material Adverse Effect on COMSAT or would reasonably be expected to
    materially adversely affect (or materially delay) the consummation of
    the Offer, (iv) any limitation or proposed limitation (whether or not
    mandatory) by any Governmental Authority or other instrumentality of
    the United States of America that materially adversely affects
    generally the extension of credit by banks or other financial
    institutions, or (v) in the case of any of the situations described in
    clauses (i) through (iv) inclusive, existing at the date of the
    commencement of the Offer, a material acceleration, escalation or
    worsening thereof; or
 
       (f) (i) there shall have been a decline in the Standard & Poor's 500
    Index of at least 27% from the date hereof through any given day (a
    "Measurement Date") prior to the termination or expiration of the
    Offer, and (ii) the Standard & Poor's 500 Index shall also be at least
    27% lower than on the date hereof on the earlier of (A) the close of
    trading on the next trading date at least 30 calendar days from such
    Measurement Date, and (B) the close of trading on the trading date
    immediately prior to the date on which the Offer Closing Time would
    otherwise occur, but for the failure of this condition; or
 
       (g) prior to the purchase of Shares pursuant to the Offer, the Board
    of Directors of COMSAT shall have (1) recommended an Acquisition
    Proposal that is a Superior Proposal, (2) withdrawn, modified or
    materially qualified (including by amendment of the Schedule 14D-9) in
    a manner adverse to Lockheed Martin its approval or recommendation of
    the Offer, the Merger or the Merger Agreement, (3) recommended to
    COMSAT's shareholders another offer, or (4) adopted any resolution to
    effect any of the foregoing which, in the sole judgment of Lockheed
    Martin in any such case, and regardless of the circumstances (including
    any action or omission by Lockheed Martin) giving rise to any such
    condition, makes it inadvisable to proceed with such acceptance for
    payment; or
 
       (h) the Merger Agreement shall have been terminated in accordance
    with its terms.
 
   The foregoing conditions are for the sole benefit of Lockheed Martin and may
be asserted by Lockheed Martin regardless of the circumstances giving rise to
such conditions, or may be waived by Lockheed Martin in whole or in part at any
time and from time to time in its sole discretion.
 
                                     I-A-2
<PAGE>
 
                                                                     APPENDIX II
 
      SECTION 29-373 OF THE DISTRICT OF COLUMBIA BUSINESS CORPORATION ACT
                             TITLE 29. CORPORATIONS
                    CHAPTER 3. BUSINESS CORPORATIONS (1954)
          MERGER OR CONSOLIDATION--RIGHTS OF DISSENTING SHAREHOLDERS.
 
   (a) If a shareholder of a corporation which is a party to a merger or
consolidation shall file with the corporation, prior to or at the meeting of
shareholders at which the plan of merger or consolidation is submitted to a
vote, a written objection to the plan of merger or consolidation, and shall not
vote in favor of the plan, and the shareholder, within 20 days after the merger
or consolidation is effected, shall make written demand on the surviving or new
corporation for payment of the fair value of his shares as of the day prior to
the date on which the vote was taken approving the merger or consolidation, the
surviving or new corporation shall pay to the shareholder the fair value of the
shares forthwith, in the case of holders of uncertificated shares, or upon
surrender of the certificate or certificates representing the shares, in the
case of holders of shares represented by certificates. Such a demand shall
state the number and class of the shares owned by the dissenting shareholder.
Any shareholder failing to make demand within the 20-day period shall be bound
by the terms of the merger or consolidation.
 
   (b) If within 30 days after the date on which the merger or consolidation
was effected the value of the shares is agreed upon between the dissenting
shareholder and the surviving or new corporation payment therefor shall be made
within 90 days after the date on which the merger or consolidation was
effected, in the case of holders of uncertificated shares, or upon surrender of
the certificate or certificates representing the shares, in the case of holders
of shares represented by certificates. Upon payment of the agreed value, the
dissenting shareholder shall cease to have any interest in the shares of the
corporation.
 
   (c) If within the period of 30 days the shareholder and the surviving or new
corporation do not agree, the dissenting shareholder may, within 60 days after
the expiration of the 30-day period, file a petition in any court of competent
jurisdiction within the District of Columbia asking for a finding and
determination of the fair value of the shares, and shall be entitled to
judgment against the surviving or new corporation for the amount of the fair
value as of the day prior to the date on which the vote was taken approving the
merger or consolidation, together with interest at the rate of 5% per annum to
the date of the judgment. The judgment shall be payable forthwith, in the case
of holders of uncertificated shares, or upon surrender of the certificate or
certificates representing the shares to the surviving or new corporation, in
the case of holders of shares represented by certificates. Upon payment of the
judgment, the dissenting shareholder shall cease to have any interest in the
shares or in the surviving or new corporation. The shares may be held and
disposed of by the surviving or new corporation as it may see fit. Unless the
dissenting shareholder shall file the petition within the time herein limited,
the shareholder and all persons claiming under him shall be bound by the terms
of the merger or consolidation.
 
   (d) The right of a dissenting shareholder to be paid the fair value of his
shares as herein provided shall cease if and when the corporation shall abandon
the merger and consolidation.
 
                                      II-1
<PAGE>
 
                                                                    APPENDIX III
                          Donaldson, Lufkin & Jenrette
                       Donaldson, Lufkin & Jenrette, Inc.
           277 Park Avenue, New York, New York 10172 - (212) 692-3000
 
                                                        As of September 18, 1998
 
Board of Directors
COMSAT Corporation
6560 Rock Spring Drive
Bethesda, MD 20817
 
Ladies and Gentlemen:
 
   You have requested our opinion as to the fairness, from a financial point of
view, to the stockholders of COMSAT Corporation (the "Company") of the
Consideration (as defined below) to be received by such stockholders pursuant
to the terms of the Agreement and Plan of Merger, dated as of September 18,
1998 (the "Agreement"), among Lockheed Martin Corporation ("Lockheed Martin"),
DENEB Corporation ("DENEB"), a wholly owned subsidiary of Lockheed Martin, and
the Company, pursuant to which the Company will be merged with and into DENEB
(or, if certain conditions in the Agreement are not satisfied, DENEB will be
merged with and into the Company) (the "Merger").
 
   Pursuant to the Agreement, Lockheed Martin, through a wholly owned, single
member Delaware limited liability company ("Offer Subsidiary"), will commence a
cash tender offer (the "Tender Offer") for up to the number of shares of the
Company's common stock, without par value (the "Company Common Stock"), that is
equal to the remainder of (i) 49% of the number of shares of Company Common
Stock outstanding at the close of business on the date of purchase pursuant to
the Tender Offer minus (ii) the number of shares of Company Common Stock then
owned of record by "authorized carriers" (as defined in the Communications
Satellite Act of 1962, as amended) as evidenced by issuance of shares of Series
II Company Common Stock minus (iii) the number of shares of Company Common
Stock with respect to which written demand shall have been made and not
withdrawn under the District of Columbia Business Corporation Act ("Dissenting
Shares"), at a price of not less than $45.50 per share, net to the seller in
cash (the "Tender Offer Consideration").
 
   Pursuant to the Agreement, subsequent to the Tender Offer and subject to the
satisfaction of the conditions contained in the Agreement, the Company shall be
merged with and into DENEB (or, if certain conditions in the Agreement are not
satisfied, DENEB shall be merged with and into the Company) and each share of
Company Common Stock issued and outstanding (other than shares of Company
Common Stock held in the treasury of the Company, held by Offer Subsidiary,
held by Lockheed Martin, if any, and Dissenting Shares) shall, by virtue of the
Merger and without any action on the part of the holder thereof, be converted
into the right to receive 0.5 (the "Exchange Ratio") shares of Lockheed Martin
Common Stock, par value $1 per share (the "Lockheed Martin Common Stock") (the
"Merger Consideration"). The Tender Offer Consideration and the Merger
Consideration are collectively referred to as the "Consideration" and the
Tender Offer and the Merger are collectively referred to as the "Consideration"
and the Tender Offer and the Merger are collectively referred to as the
"Transaction".
 
   In arriving at our opinion, we have reviewed the drafts dated September 18,
1998 of the Agreement and the exhibits thereto. We also have reviewed financial
and other information that was publicly available or furnished to us by the
Company and Lockheed Martin, including information provided during discussions
with their respective managements. Included in the information provided during
discussions with the Company's management were certain financial projections of
the Company for the period beginning January 1, 1998 and ending December 31,
2002 prepared by the management of the Company. In addition, we have compared
certain financial and securities data of the Company with various other
companies whose securities are traded
 
                                     III-1
<PAGE>
 
in public markets, reviewed the historical stock prices and trading volumes of
the respective common stocks of the Company and Lockheed Martin, reviewed
prices and premiums paid in certain other business combinations and conducted
such other financial studies, analyses and investigations as we deemed
appropriate for purposes of this opinion. We were not requested to, nor did we,
solicit the interest of any other party in acquiring the Company.
 
   In rendering our opinion, we have relied upon and assumed the accuracy and
completeness of all of the financial and other information that was available
to us from public sources, that was provided to us by the Company and Lockheed
Martin or their respective representatives, or that was otherwise reviewed by
us. With respect to the financial projections supplied to us, we have assumed
that they have been reasonably prepared on the basis reflecting the best
currently available estimates and judgments of the management of the Company as
to the future operating and financial performance of the Company. We have not
assumed any responsibility for making any independent evaluation of any assets
or liabilities of either the Company or Lockheed Martin or for making any
independent verification of any of the information previewed by us. We have
also assumed that the Tender Offer and the Merger and the other transactions
contemplated by the Agreement will be consummated as described in the
Agreement. We have relied as to certain legal matters on advice of counsel to
the Company.
 
   Our opinion is necessarily based on economic, market, regulatory, financial
and other conditions as they exist on, and on the information made available to
us as of, the date of this letter. It should be understood that, although
subsequent developments may affect this opinion, we do not have any obligation
to update, revise or reaffirm this opinion. We are expressing no opinion herein
as to the prices at which Lockheed Martin Common Stock will actually trade at
any time. Our opinion does not address the relative merits of the Transaction
and the other business strategies being considered by the Company's Board of
Directors, nor does it address the Board's decision to proceed with the
Transaction. Our opinion does not constitute a recommendation to any
stockholder as to how such stockholder should vote on the proposed transaction.
 
   Donaldson, Lufkin & Jenrette Securities Corporation ("DLJ"), as part of its
investment banking services, is regularly engaged in the valuation of
businesses and securities in connection with mergers, acquisitions,
underwritings, sales and distributions of listed and unlisted securities,
private placements and valuations for corporate and other purposes. DLJ has
performed investment banking and other services for the Company in the past and
has received customary compensation for such services.
 
   Based upon the foregoing and such other factors as we deem relevant, we are
of the opinion that, as of the date hereof, the Consideration to be received by
the stockholders of the Company pursuant to the Agreement is fair to such
stockholders from a financial point of view.
 
                                          Very truly yours,
 
                                          DONALDSON, LUFKIN & JENRETTE
                                           SECURITIES CORPORATION
 
                                                   /s/ Douglas V. Brown
                                          By___________________________________
                                                  Douglas V. Brown
                                                 Managing Director
 
                                     III-2
<PAGE>
 
                                                                     APPENDIX IV
 
                       RESTATED ARTICLES OF INCORPORATION
 
                                       OF
 
                               COMSAT CORPORATION
 
To:Department of Consumer
    and Regulatory Affairs
   Corporations Division
 
   We, the undersigned natural persons of the age of eighteen years or more,
authorized to act on behalf of the corporation described below, present the
following Restated Articles of Incorporation duly proposed and adopted in
accordance with all applicable provisions of Title 29, Chapter 3 of the
District of Columbia Code, as amended.
 
                                   ARTICLE I
 
   Section 1.01. The name of the corporation is:
 
                      COMSAT Corporation (the "Corporation").
 
   Section 1.02. The Articles of Incorporation of the Corporation were
originally filed with the Department of Consumer and Regulatory Affairs of the
District of Columbia on February 1, 1963.
 
                                   ARTICLE II
 
   Section 2.01. The period of duration of the Corporation is perpetual.
 
                                  ARTICLE III
 
   Section 3.01. The Restated Articles of Incorporation were advised by the
Board of Directors of the Corporation and approved by a vote of the
shareholders of the Corporation in accordance with Section 29-358.1 of the
District of Columbia Business Corporation Act.
 
                                   ARTICLE IV
 
   Section 4.01. The purposes for which the Corporation is organized are:
 
     (a) to plan, initiate, construct, own, manage, and operate, itself or in
  conjunction with foreign governments or with business entities, a
  commercial communications satellite system; and
 
     (b) to do everything necessary, desirable, advisable, or convenient for
  the furtherance and accomplishment of such purposes and the achievement of
  such objectives, and to do all other things which are incidental thereto,
  are connected therewith, and which are not forbidden by applicable law or
  these Articles, including without limitation to acquire, own, use, convey,
  and otherwise dispose of and deal in real property or any interest therein.
 
 
                                      IV-1
<PAGE>
 
   Section 4.02. In order to further and carry out any or all of the purposes
of the Corporation, the Corporation shall have the power to:
 
     (a) furnish, for hire, channels of communication to United States
  communications common carriers and to other authorized entities, foreign
  and domestic;
 
     (b) own and operate satellite terminal stations;
 
     (c) conduct or contract for research and development related to its
  mission;
 
     (d) acquire the physical facilities, equipment, and devices necessary to
  its operations, including communications satellites and associated
  equipment and facilities, whether by construction, purchase, or gift;
 
     (e) purchase satellite launching and related services;
 
     (f) contract with users, including among others the United States
  Government, for the services of the communications satellite system and of
  satellite terminal stations;
 
     (g) develop plans for the terminal specifications of all elements of the
  communications satellite system and of satellite terminal stations;
 
     (h) engage, to the extent permitted by applicable law, in any other
  phase of telecommunications or telecommunications research that may further
  or carry out any or all of the purposes of the Corporation;
 
     (i) have perpetual succession by its corporate name;
 
     (j) sue and be sued, complain and defend, in its corporate name;
 
     (k) have a corporate seal, which may be altered at pleasure, and use the
  same by causing it, or a facsimile thereof, to be impressed or affixed or
  in any other manner reproduced;
 
     (l) purchase, take, receive, lease, take by gift, devise, or bequest, or
  otherwise acquire, and own, hold, improve, use, and otherwise deal in and
  with real or personal property, or any interest therein, wherever situated;
 
     (m) sell, convey, mortgage, pledge, lease, exchange, transfer, and
  otherwise dispose of all or any part of its property and assets;
 
     (n) acquire (by purchase, exchange, lease, hire, or otherwise), hold,
  use, sell, assign, lease, and grant the absolute interest in and to, and
  license or sublicense in respect of, franchises, indeterminate permits,
  certificates of convenience and necessity, certificates of authority,
  letters patent, patent rights, licenses, privileges, inventions,
  improvements, processes, copyrights, trademarks, and trade names;
 
     (o) lend money to, and otherwise assist, its employees, other than its
  officers and directors;
 
     (p) purchase, take, receive, subscribe for, or otherwise acquire, own,
  hold, vote, use, employ, sell, mortgage, loan, pledge, or otherwise dispose
  of, and otherwise use and deal in and with, shares or other interests in,
  or obligations of, other corporations organized under the laws of the
  District of Columbia, or of any State, Territory, district, or possession
  of the United States, or of the Commonwealth of Puerto Rico, foreign
  corporations, and associations, partnerships, or individuals;
 
     (q) make contracts and incur liabilities; borrow money at such rates of
  interest as the Corporation may determine without regard to the
  restrictions of any usury law; determine without regard to the restrictions
  of any usury law; issue its notes, bonds, and other obligations, and secure
  any of its obligations by mortgage or pledge of all or any of its property,
  franchises, and income;
 
     (r) invest its surplus funds from time to time and lend money for its
  corporate purposes, and take and hold real and personal property as
  security for the payment of funds so invested or loaned;
 
     (s) subject to applicable law, conduct its business, carry on its
  operations, and have offices and exercise its powers within and without the
  district of Columbia, including any State, Territory, district, or
  possession of the United States, the Commonwealth of Puerto Rico, and any
  foreign country;
 
                                      IV-2
<PAGE>
 
     (t) elect or appoint officers and agents of the Corporation, and define
  their duties and fix their compensation;
 
     (u) make and alter By-laws, not inconsistent with applicable law or
  these Articles, for the administration and regulation of the affairs of the
  Corporation;
 
     (v) make contributions to charitable, scientific, and educational
  organizations, and transact any lawful business in aid of the United States
  and furthering the purposes and objectives of the Satellite Act;
 
     (w) cease its corporate activities and surrender its corporate
  franchise;
 
     (y) indemnify any and all of its incorporators, directors, or officers,
  or former incorporators, directors, or officers, or any person who may have
  served at its request as an incorporator, director, or officer of another
  corporation in which its owns shares of capital stock or of which it is a
  creditor, against expenses actually and necessarily incurred by them in
  connection with the defense of any action, suit, or proceeding in which
  they, or any of them, are made parties, or a party, by reason of being or
  having been incorporators, directors, or officers, or an incorporator,
  director, or officer of the Corporation, or of such other corporation,
  except in relation to matters as to which any such incorporator, director,
  or officer, or former incorporator, director, or officer, or person shall
  be adjudged in such action, suit, or proceeding to be liable for negligence
  or misconduct in the performance of duty to the Corporation or to such
  other corporation. Such indemnification shall not be deemed exclusive of
  any other rights to which those indemnified may be entitled, under any By-
  law, agreement, vote of shareholders, or otherwise;
 
     (z) subject to the provisions of applicable law and these Articles,
  purchase, take, receive, or otherwise acquire, hold, own, pledge, transfer,
  or otherwise dispose of its own shares;
 
     (aa) act in the District of Columbia and in any State, Territory,
  district, or possession of the United States, or in the Commonwealth of
  Puerto Rico, or in any foreign country, in the capacity of agent or
  representative for any government, individual, corporation, association,
  partnership, or other entity, respecting any business the purpose of which
  is related to the purposes set forth in this Article;
 
     (bb) enter into any lawful arrangement for sharing profits, union of
  interest, reciprocal association, or cooperative association with any
  government, individual, corporation, association, partnership, or other
  entity, and enter into any general or limited partnership, for the carrying
  on of any business or activity within the authority of the Corporation;
 
     (cc) make any guaranty respecting stocks, dividends, securities,
  indebtedness, interest, contracts, or other obligations created by any
  individual, corporation, association, partnership, or other entity, to the
  extent that such guaranty is made in pursuance of the purposes set forth in
  this Article;
 
     (dd) subject to the provisions of applicable law and these Articles,
  issue shares of stock to such persons and on such terms as may be in the
  interest of the Corporation;
 
     (ee) subject to the provisions of applicable law and these Articles, pay
  pensions and establish pension plans, pension trusts, profitsharing plans,
  stock bonus plans, stock option plans, and other incentive plans for any or
  all of is officers and employees; provided that nothing herein shall be
  construed to authorize the Corporation to engage in the business of banking
  or insurance or the acceptance and execution of trusts; and
 
     (ff) without limiting the foregoing in any way, perform such other acts,
  engage in such other operations, and exercise such other powers as are or
  may be authorized or as are not forbidden by applicable law, and as may be
  necessary, desirable, advisable, or convenient to further carry out any or
  all of the purposes of the Corporation.
 
   Section 4.03. (a) To the full extent permitted by law, the Corporation shall
indemnify any person who was or is a party or is threatened to be made a party
to any threatened, pending or completed action, suit or proceeding (including
civil, criminal, administrative or investigative actions, suits or proceedings)
brought by or in the right of the Corporation or any wholly owned subsidiary of
the Corporation (a "Subsidiary") or otherwise, by reason of the fact that such
person (hereinafter, a "Person Entitled to Indemnification") is or was
 
                                      IV-3
<PAGE>
 
or has agreed to become a director, advisory director, or officer of the
Corporation, or is or was a director or officer of a Subsidiary, or is or was
serving or has agreed to serve at the request of the Corporation or a
Subsidiary as a director, officer, trustee or other fiduciary of another
corporation, partnership, joint venture, trust or other enterprise, including
employee benefit plans, or by reason of any action alleged to have been taken
or omitted in such capacity, against costs, charges and expenses (including
attorneys' fees) reasonably incurred by him or on his behalf in connection with
the defense or settlement of any threatened, pending or completed action, suit
or proceeding, and any appeal therefrom, or in defense or settlement of any
claim, issue or matter, except that no indemnification pursuant to this
paragraph shall be made in respect of any claim, issue or matter as to which
such person shall have been adjudged liable for negligence or misconduct in the
performance of duty by a court of competent jurisdiction. The termination of
any claim, action, suit or proceeding by settlement, conviction or upon a plea
of nolo contendere or its equivalent shall not, in itself, create a presumption
that any such person was adjudged liable for negligence or misconduct in the
performance of duty.
 
   (b) To the full extent permitted by law, the Corporation shall, upon
request, pay costs, charges and expenses (including attorneys' fees) incurred
by Persons Entitled to Indemnification in advance of the final disposition of
any such action, suit or proceeding; provided, however, that the payment of
such costs, charges and expenses incurred by a Person Entitled to
Indemnification in the capacity in which he became entitled to indemnification
(and not in any other capacity in which service was or is rendered by such
person) in advance of the final disposition of such action, suit or proceeding
shall be made only upon receipt of an undertaking by or on behalf of such
person to repay all amounts so advanced in the event that it shall ultimately
be determined that he is not entitled to be indemnified by the Corporation
pursuant to this Section 4.03, or otherwise.
 
   (c) To the full extent permitted by law, the Corporation, in the sole
discretion of the Board of Directors, may indemnify any person who was or is a
party or is threatened to be made a party to any threatened, pending or
completed actin, suit or proceeding (including civil, criminal, administrative
or investigative actions, suits or proceedings) brought by or in the right of
the Corporation or a Subsidiary, or otherwise, by reason of the fact that such
person is or was or has agreed to become an employee or agent of the
Corporation or a Subsidiary, or is or was serving or has agreed to serve at the
request of the Corporation or a Subsidiary as an employee, agent, trustee or
other fiduciary of another corporation, partnership, joint venture, trusts or
other enterprise, including employee benefit plans, or by reason of any action
alleged to have been taken or omitted in such capacity, against all costs,
charges and expenses (including attorneys' fees) reasonably incurred by him or
on his behalf in connection with the defense or settlement of any threatened,
pending or completed actin, suit or proceeding, and any appeal therefrom or in
defense or settlement of any claim, issue or matter, except that no
indemnification pursuant to this paragraph shall be made in respect of any
claim, issue or matter as to which such person shall have been adjudged liable
for negligence or misconduct in the performance of duty by a court of competent
jurisdiction. The termination of any claim, action, suit or proceeding by
settlement, conviction or upon a plea of nolo contendere or its equivalent,
shall not in itself create a presumption that any such person was adjudged
liable for negligence or misconduct in the performance of duty.
 
   (d) To the full extent permitted by law, the Corporation may, upon request,
pay costs, charges and expenses (including attorneys' fees) incurred by persons
entitled to indemnification pursuant to paragraph (c) of this Section 4.03 in
advance of the final disposition of such action, suit or proceeding; provided,
however, that the payment of such costs, charges and expenses incurred by any
such person in the capacity in which he became entitled to indemnification (and
not in any other capacity in which service was or is rendered by such person)
in advance of the final disposition of such action, suit or proceeding shall be
made only upon receipt of an undertaking by or on behalf of such person to
repay all amounts so advanced in the event that it shall ultimately be
determined that he is not entitled to be indemnified by the Corporation
pursuant to this Section 4.03, or otherwise.
 
   (e) Any indemnification or advance of costs, charges and expenses provided
for in paragraphs (a) and (b) of this Section 4.03 shall be made promptly, and
in any event within sixty (60) days, upon the written request
 
                                      IV-4
<PAGE>
 
of the Person Entitled to Indemnification; the right to indemnification or
advances as granted by paragraphs (a) and (b) of this Section 4.03 shall be
enforceable by the Person Entitled to Indemnification in any court of competent
jurisdiction. If the Corporation denies such request, in whole or in part, or
if no disposition thereof is made within sixty (60) days, such Person Entitled
to Indemnification's costs, charges and expenses incurred in indemnification,
in whole or in part, in any such action shall also be indemnified by the
Corporation, it shall be a defense to any such action (other than an action
brought to enforce a claim for the advance of costs, charges and expenses under
paragraph (b) of this Section 4.03 where the required undertaking, if any, has
been received by the Corporation) that the Person Entitled to Indemnification
has not met the standard set forth in paragraph (a) of this Section 4.03, but
the burden of proving such defense shall be on the Corporation. Neither the
failure of the Corporation (including its Board of Directors, its independent
legal counsel, and its shareholders) to have made a determination prior to the
commencement of such action that indemnification of the claimant is proper in
the circumstances because he has met the applicable standard of conduct set
forth in paragraph (a) of this Section 4.03, nor the fact that there has been
an actual determination by the Corporation (including its Board of Directors,
its independent legal counsel, and its shareholders) that the claimant has not
met such applicable standard of conduct, shall be a defense to the action or
create a presumption that the claimant has not met the applicable standard of
conduct.
 
   (f) The provisions of paragraphs (a) and (b) of this Section 4.03 shall be
applicable to claims, actions, suits or proceedings made or commenced after the
adoption hereof, whether arising from acts or omissions occurring before or
after the adoption hereof.
 
   (g) The indemnification and advancement of expenses provided by this Section
4.03 shall not be deemed exclusive of any other rights to which a person
seeking indemnification or advancement of expenses may be entitled under any
law (present or future, common or statutory), by-law, agreement, vote of
shareholders or otherwise and shall continue as to a person who has ceased to
serve in the capacity making him eligible for indemnification, and shall inure
to the benefit of the estate, heirs, executors and administrators of such
person. To the full extent permitted by law, the Corporation may enter into and
perform agreements with persons, including, without limitation, present and
former officers, directors and employees of the Corporation and its
Subsidiaries and of companies acquired by or merged with the Corporation or any
of its subsidiaries, obligating the Corporation, among other things, to provide
indemnification and advancement of costs, charges and expenses to such persons
in addition to any indemnification or advancement which may be available to
such person under this Section 4.03.
 
   (h) All rights to indemnification under this Section 4.03 shall be deemed to
be a contract between the Corporation and each Person Entitled to
Indemnification who serves or served in such capacity at any time while this
Section 4.03 is in effect. Any repeal or modification of this Section 4.03 or
any repeal or modification of the relevant provisions of the District of
Columbia Business Corporation Act or of any other applicable law shall not in
any way diminish any rights to indemnification of any person or the obligation
of the Corporation arising prior to such repeal or modification.
 
   (i) If this Section 4.03 or any portion hereof shall be invalidated on any
ground in any court of competent jurisdiction, then the Corporation shall
nevertheless indemnify each Person Entitled to Indemnification, and may
nevertheless indemnify each person whom the Corporation has determined to
indemnify pursuant to paragraphs (c) and (g) of this Section 4.03, to the full
extent permitted by any applicable portion of this Section 4.03 that shall not
have been so invalidated (whether under paragraphs (c) or (g) or any other
applicable provision of this Section 4.03), and to the full extent permitted by
applicable law.
 
                                   ARTICLE V
 
   Section 5.01. The restated aggregate number of shares which the Corporation
is authorized to issue is 1,000, all of which are without par value and are of
the same class and are to be shares of Common Stock.
 
 
                                      IV-5
<PAGE>
 
                                   ARTICLE VI
 
   Section 6.01. The Corporation will not commence business until at least One
Thousand Dollars ($1,000.00) has been received by it in consideration for the
issuance of shares.
 
                                  ARTICLE VII
 
   Section 7.01. No shareholder of the Corporation shall, by reason of his
ownership of shares, have a preemptive or preferential right to purchase,
subscribe to, or take any shares of stock of the Corporation, whether now or
hereafter authorized, or any part of the notes, debentures, bonds or other
securities of the Corporation, whether or not convertible into or carrying
options or warrants to purchase shares of stock, other than such rights, if
any, and at such price and other terms, as the Board of Directors, in its
discretion, from time to time may determine, and the Board of Directors may
issue such shares or other securities without offering them in whole or in part
to the shareholders of the Corporation.
 
                                  ARTICLE VIII
 
   Section 8.01. The address, including street and number, of the initial
registered office of the Corporation is:
 
         United States Corporation Company
         National Press Building
         1346 F Street, N.W.
         Washington, D.C.
 
     and the name of its initial registered agent at such address is:
 
         United States Corporation Company.
 
                                   ARTICLE IX
 
   Section 9.01. The Corporation reserves the right to amend, alter, change, or
repeal any provision contained in these Articles in the manner now or hereafter
prescribed by law.
 
                               ----------------
 
        [The remainder of this page has been left blank intentionally.]
 
 
                                      IV-6
<PAGE>
 
   IN WITNESS WHEREOF, the undersigned has set his hand this   day of       ,
199 .
 
(Corporate Seal)                          COMSAT Corporation
 
 
                                          By: _________________________________
 
 
                                             Name: ____________________________
 
                                             Its: President [or Vice
                                             President]
 
Attest:
 
 
By: _________________________________
 
 
  Name: ____________________________
 
  Its: Secretary [or Assistant Secretary]
 
                                      IV-7
<PAGE>
 
                                    PART II.
 
                     INFORMATION NOT REQUIRED IN PROSPECTUS
 
Item 20. Indemnification of Directors and Officers.
 
   The Registrant's Bylaws provide that the Registrant shall indemnify and
advance expenses to its currently acting and its former directors to the
fullest extent permitted by the Maryland General Corporation Law, and that the
Registrant may indemnify and advance expenses to its officers to the same
extent as its directors and to such further extent as is consistent with law.
The Maryland General Corporation Law provides that a corporation may indemnify
any director made a party to any proceeding by reason of service in that
capacity unless it is established that: (1) the act or omission of the director
was material to the matter giving rise to the proceeding and (a) was committed
in bad faith or (b) was the result of active and deliberate dishonesty, or (2)
the director actually received an improper personal benefit in money, property
or services, or (3) in the case of any criminal proceeding, the director had
reasonable cause to believe that the act or omission was unlawful. The statute
permits a Maryland corporation to indemnify its officers, employees or agents
to the same extent as its directors and to such further extent as is consistent
with law. In addition to indemnification, the officers and directors of the
Registrant are covered by certain insurance policies maintained by the
Registrant.
 
   The Registrant's Charter provides that, to the fullest extent that
limitations on the liability of directors and officers are permitted by the
Maryland General Corporation Law, no director or officer of the Registrant,
shall have any liability to the Registrant or any of its stockholders for
monetary damages. The Maryland General Corporation Law provides that a
corporation's charter may include a provision which restricts or limits the
liability of its directors or officers to the corporation or its stockholders
for money damages except: (1) to the extent that it is proved that the person
actually received an improper benefit or profit in money, property or services,
for the amount of the benefit or profit in money, property or services actually
received, or (2) to the extent that a judgment or other final adjudication
adverse to the person is entered in a proceeding based on a finding in the
proceeding that the person's action, or failure to act, was the result of
active and deliberate dishonesty and was material to the cause of action
adjudicated in the proceeding. In situations to which the Registrant's Charter
provision applies, the remedies available to the Registrant or a stockholder
are limited to equitable remedies such as injunction or recession. This
provision would not, in the opinion of the Commission, eliminate or limit the
liability of directors and officers under federal securities laws.
 
Item 21. Exhibits and Financial Statement Schedules.
 
<TABLE>
 <C>   <S>
  2.1  Agreement and Plan of Merger, dated as of September 18, 1998, among the
       Registrant, Deneb Corporation and COMSAT Corporation (attached as
       Appendix I to the Proxy Statement/Prospectus included in this
       Registration Statement).
 
  2.2  Form of Proxy for holders of COMSAT Corporation Common Stock.
 
  5.1  Opinion of King & Spalding.
 
  8.1  Tax Opinion of King & Spalding.
 
  8.2  Tax Opinion of Skadden, Arps, Slate, Meagher & Flom LLP.
 
 10.1* Confidentiality Agreements, dated August 5, 1997, between COMSAT
       Corporation and the Registrant.
 
 10.2* Shareholders Agreement, dated as of September 18, 1998, between COMSAT
       Corporation and the Registrant.
 
 10.3* Registration Rights Agreement, dated as of September 18, 1998, between
       COMSAT Corporation and the Registrant.
 
 10.4* Carrier Acquisition Agreement, dated as of September 18, 1998, among
       COMSAT Corporation, the Registrant, Regulus, LLC and COMSAT Government
       Systems, Inc.
 
 10.5  Opinion of Donaldson, Lufkin & Jenrette Securities Corporation, dated as
       of September 18, 1998 (attached as Appendix III to the Proxy
       Statement/Prospectus included in this Registration Statement).
 
</TABLE>
 
 
                                      II-1
<PAGE>
 
<TABLE>
<S>   <C>
23.1  Consent of Ernst & Young LLP, independent auditors.
 
23.2  Consent of Deloitte & Touche LLP, independent auditors.
 
23.3  Consent of King & Spalding (included in the opinions filed as Exhibits 5.1
      and 8.1).

23.4  Consent of Skadden, Arps, Slate, Meagher & Flom LLP (included in the
      opinion filed as Exhibit 8.2).

23.5  Consent of Donaldson, Lufkin & Jenrette Securities Corporation.
 
24.1  Powers of Attorney.
</TABLE>
- --------
* Incorporated by reference from the Registrant's Schedule 14D-1 filed with the
  Commission on September 25, 1998.
 
Item 22. Undertakings.
 
   The undersigned Registrant hereby undertakes:
 
     (1) To file, during any period in which offers or sales are being made,
  a post-effective amendment to this Registration Statement:
 
       (i) To include any prospectus required by section 10(a)(3) of the
    Securities Act of 1933 (the "Act");
 
       (ii) To reflect in the prospectus any facts or events arising after
    the effective date of the Registration Statement (or the most recent
    post-effective amendment thereof) which, individually or in the
    aggregate, represent a fundamental change in the information set forth
    in the Registration Statement;
 
       (iii) To include any material information with respect to the plan
    of distribution not previously disclosed in the Registration Statement
    or any material change to such information in the Registration
    Statement; provided, however, that paragraphs (i) and (ii) do not apply
    if the Registration Statement is on Form S-3 or Form S-8, and the
    information required to be included in a post-effective amendment by
    those paragraphs is contained in periodic reports filed by the
    Registrant pursuant to section 13 or section 15(d) of the Securities
    Exchange Act of 1934 (the "Exchange Act") that are incorporated by
    reference in the Registration Statement.
 
     (2) That, for the purpose of determining any liability under the Act,
  each such post-effective amendment shall be deemed to be a new registration
  statement relating to the securities offered therein, and the offering of
  such securities at that time shall be deemed to be the initial bona fide
  offering thereof.
 
     (3) To remove from registration by means of a post-effective amendment
  any of the securities being registered which remain unsold at the
  termination of the offering.
 
   The undersigned Registrant hereby undertakes that, for purposes of
determining any liability under the Act, each filing of the Registrant's annual
report pursuant to section 13(a) or section 15(d) of the Exchange Act (and,
where applicable, each filing of an employee benefit plan's annual report
pursuant to section 15(d) of the Exchange Act) that is incorporated by
reference in the Registration Statement shall be deemed to be a new
registration statement relating to the securities offered therein, and the
offering of such securities at that time shall be deemed to be the initial bona
fide offering thereof.
 
   Insofar as indemnification for liabilities arising under the Act may be
permitted to directors, officers and controlling persons of the Registrant
pursuant to the foregoing provisions, or otherwise, the Registrant has been
advised that in the opinion of the Securities and Exchange Commission such
indemnification is against public policy as expressed in the Act and is,
therefore, unenforceable. In the event that a claim for indemnification against
such liabilities (other than the payment by the Registrant of expenses incurred
or paid by a director, officer or controlling person of the Registrant in the
successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered, the Registrant will, unless in the opinion of its counsel the
matter has been settled by controlling precedent, submit
 
                                      II-2
<PAGE>
 
to a court of appropriate jurisdiction the question whether such
indemnification by it is against public policy as expressed in the Act and will
be governed by the final adjudication of such issue.
 
   The undersigned Registrant hereby undertakes as follows: that prior to any
public reoffering of the securities registered hereunder through use of a
prospectus which is a part of this Registration Statement, by any person or
party who is deemed to be an underwriter within the meaning of Rule 145(c), the
issuer undertakes that such reoffering prospectus will contain the information
called for by the applicable registration form with respect to reofferings by
persons who may be deemed underwriters, in addition to the information called
for by the other items of the applicable form.
 
   The Registrant undertakes that every prospectus (i) that is filed pursuant
to the immediately preceding paragraph, or (ii) that purports to meet the
requirements of section 10(a)(3) of the Act and is used in connection with an
offering of securities subject to Rule 415, will be filed as a part of an
amendment to the Registration Statement and will not be used until such
amendment is effective, and that, for purposes of determining any liability
under the Act, each such post-effective amendment shall be deemed to be a new
registration statement relating to the securities offered therein, and the
offering of such securities at that time shall be deemed to be the initial bona
fide offering thereof.
 
   The undersigned Registrant hereby undertakes to respond to requests for
information that is incorporated by reference into the prospectus pursuant to
Items 4, 10(b), 11 or 13 of this Form, within one business day of receipt of
such request, and to send the incorporated documents by first class mail or
other equally prompt means. This includes information contained in documents
filed subsequent to the effective date of the registration statement through
the date of responding to the request.
 
   The undersigned Registrant hereby undertakes to supply by means of a post-
effective amendment all information concerning a transaction, and the company
being acquired involved therein, that was not the subject of and included in
the Registration Statement when it became effective.
 
                                      II-3
<PAGE>
 
                                   SIGNATURES
 
     Pursuant to the requirements of the Securities Act of 1933, the Registrant
has duly caused this Registration Statement to be signed on its behalf by the
undersigned, thereunto duly authorized, in the County of Montgomery, State of
Maryland, on the 11th day of May, 1999.
 
                                          Lockheed Martin Corporation
 
                                               /s/ Frank H. Menaker, Jr.
                                          By: _________________________________
                                                   Frank H. Menaker, Jr.
                                             Senior Vice President and General
                                                          Counsel
 
                               POWER OF ATTORNEY
 
     Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities and on the date indicated.
 
<TABLE>
<CAPTION>
              Signature                         Capacity                 Date
              ---------                         --------                 ----
 
<S>                                    <C>                        <C>
      /s/ Vance D. Coffman*            Chairman and Chief            May 11, 1999
______________________________________  Executive Officer
           Vance D. Coffman             (Principal Executive
                                        Officer)
 
       /s/ Philip J. Duke*             Vice President and Chief      May 11, 1999
______________________________________  Financial Officer
            Philip J. Duke              (Principal Financial
                                        Officer)
 
       /s/ Todd J. Kallman*            Vice President and Chief      May 11, 1999
______________________________________  Accounting Officer
           Todd J. Kallman              (Principal Accounting
                                        Officer)
 
     /s/ Norman R. Augustine*          Director                      May 11, 1999
______________________________________
         Norman R. Augustine
 
      /s/ Marcus C. Bennett*           Director                      May 11, 1999
______________________________________
          Marcus C. Bennett
 
       /s/ Lynne V. Cheney*            Director                      May 11, 1999
______________________________________
           Lynne V. Cheney
 
     /s/ Houston I. Flournoy*          Director                      May 11, 1999
______________________________________
         Houston I. Flournoy
 
      /s/ James F. Gibbons*            Director                      May 11, 1999
______________________________________
           James F. Gibbons
</TABLE>
 
                                      II-4
<PAGE>
 
<TABLE>
<CAPTION>
              Signature                         Capacity                 Date
              ---------                         --------                 ----
 
<S>                                    <C>                        <C>
     /s/ Edward E. Hood, Jr.*          Director                      May 11, 1999
______________________________________
         Edward E. Hood, Jr.
 
       /s/ Caleb B. Hurtt*             Director                      May 11, 1999
______________________________________
            Caleb B. Hurtt
 
      /s/ Gwendolyn S. King*           Director                      May 11, 1999
______________________________________
          Gwendolyn S. King
 
      /s/ Eugene F. Murphy*            Director                      May 11, 1999
______________________________________
           Eugene F. Murphy
 
        /s/ Frank Savage*              Director                      May 11, 1999
______________________________________
             Frank Savage
 
       /s/ Peter B. Teets*             Director                      May 11, 1999
______________________________________
            Peter B. Teets
 
    /s/ Carlisle A. H. Trost*          Director                      May 11, 1999
______________________________________
         Carlisle A. H. Trost
 
      /s/ James R. Ukropina*           Director                      May 11, 1999
______________________________________
          James R. Ukropina
 
     /s/ Douglas C. Yearley*           Director                      May 11, 1999
______________________________________
          Douglas C. Yearley
 
     *By: /s/ Marian S. Block
______________________________________
(Marian S. Block, Attorney-in-Fact**)
</TABLE>
- --------
** By authority of Powers of Attorney filed with this Registration Statement on
   Form S-4.
 
                                      II-5

<PAGE>
 
                                                                    Exhibit 2.2
 
                               COMSAT CORPORATION

             PROXY FOR ANNUAL MEETING OF SHAREHOLDERS, JUNE 18, 1999

           THIS PROXY IS SOLICITED ON BEHALF OF THE BOARD OF DIRECTORS

         The undersigned hereby appoints Betty C. Alewine, Lucy Wilson Benson
and Robert G. Schwartz, and each or any of them (with power of substitution),
proxies for the undersigned to represent and to vote, as designated on the
reverse side hereof, all shares of Common Stock of COMSAT Corporation which the
undersigned would be entitled to vote if personally present at the Annual
Meeting of its shareholders to be held on June 18, 1999, and at any reconvened
session thereof, subject to any directions indicated on the reverse side of this
card. IF NO DIRECTIONS ARE GIVEN, THIS PROXY WILL BE VOTED FOR PROPOSALS 1, 2
and 3 and AGAINST 4.

     Your vote for the election of directors may be indicated on the reverse.
Nominees are: Betty C. Alewine, Marcus C. Bennett, Lucy Wilson Benson, Edwin I.
Colodny, Lawrence S. Eagleburger, Neal B. Freeman, Caleb B. Hurtt, Peter W.
Likins, Larry G. Schafran, Robert G. Schwartz, Kathryn C. Turner and Guy P.
Wyser-Pratte.

     THIS PROXY IS CONTINUED ON THE REVERSE SIDE. PLEASE SIGN AND RETURN
PROMPTLY IN THE ENVELOPE PROVIDED. NO POSTAGE IS REQUIRED IF MAILED IN THE
UNITED STATES. IF YOU ATTEND THE MEETING AND VOTE IN PERSON, THIS PROXY WILL NOT
BE USED.

Continued and to be signed and dated on reverse side.

COMSAT CORPORATION
P.O. BOX 11141
NEW YORK, N.Y. 10203-0141
- --------------------------------------------------------------------------------

DETACH PROXY CARD HERE


Directors recommend a vote FOR Proposals 1, 2, and 3 and AGAINST Proposal 4.

1. Approval of the Merger and the Merger Agreement.

     [_] FOR        [_] AGAINST        [_] ABSTAIN

<TABLE> 
<S>                       <C>                <C>                            <C> 
2. Election of Directors  FOR all nominees   WITHHOLD AUTHORITY to vote     *EXCEPTIONS
                          listed below       for all nominees listed below
                              [_]                    [_]                        [_]
</TABLE> 

Nominees: Betty C. Alewine, Marcus C. Bennett, Lucy Wilson Benson, Edwin I.
Colodny, Lawrence S. Eagleburger, Neal B. Freeman, Caleb B. Hurtt, Peter W.
Likins, Larry G. Schafran, Robert G. Schwartz, Kathryn C. Turner and Guy P.
Wyser-Pratte.

(INSTRUCTIONS: To withhold authority to vote for any individual nominee mark the
"Exceptions" box and write that nominee's name in the space provided below.)

*Exceptions
           -----------------------------------------------------------------
3. Appointment of Deloitte & Touche LLP as independent accountants.

          [_] FOR                 [_] AGAINST           [_]  ABSTAIN
<PAGE>
 
4. Action on a shareholder proposal relating to political non-partisanship.

          [_] FOR                 [_] AGAINST           [_]  ABSTAIN

         In their discretion the proxies are authorized to vote upon such other
matters as may properly come before the meeting or any reconvened session
thereof.

Please sign exactly as name or names appear on this proxy. If stock is held
jointly, each holder should sign. If signing as attorney, trustee, executor,
administrator, custodian, guardian or corporate officer, please give full title.

[_]   Change of Address and/or
      Comments Mark Here

[_]   If You Plan to Attend the
      Annual Meeting Mark Here

DATED             , 1999

SIGNED

<PAGE>
 
                                                                     Exhibit 5.1


                        [Letterhead of King & Spalding]



                                 May 11, 1999



Lockheed Martin Corporation
6801 Rockledge Drive
Bethesda, Maryland 20817

               Re:  Lockheed Martin Corporation
                    Registration Statement on Form S-4
                    ----------------------------------

Ladies and Gentlemen:

     We have acted as special counsel to Lockheed Martin Corporation, a Maryland
corporation (the "Corporation"), in connection with the filing of a Registration
Statement on Form S-4 (as amended, the "Registration Statement") for the
registration of 39,342,917 shares of Common Stock, par value $1.00 per share
(the "Common Shares"), of the Corporation under the Securities Act of 1933, as
amended (the "Act").  In this capacity, we have reviewed the Charter of the
Corporation as certified by the State Department of Assessments and Taxation of
the State of Maryland, the Bylaws of the Corporation, the Registration Statement
(including the exhibits thereto), the corporate proceedings of the Corporation
relating to the authorization of the issuance of the Common Shares, and such
certificates and other documents as we deemed necessary or advisable for the
purpose of expressing the opinion contained herein.

     Based on the foregoing, we are of the opinion that, upon approval of the
merger of COMSAT Corporation ("COMSAT") with and into Deneb Corporation
("Deneb") or, alternatively, Deneb with and into COMSAT (the "Merger"), by the
respective stockholders of COMSAT and Deneb in accordance with the terms and
conditions of the Agreement and Plan of Merger dated as of September 18, 1998,
by and among COMSAT, the Corporation and Deneb (the "Merger Agreement"), the
filing of Articles of Merger with the Secretary of State of the State of
Delaware and a Certificate of Merger with the Department of Consumer and
Regulatory Affairs of the District of Columbia, and issuance and delivery of the
Common Shares pursuant to the Merger Agreement, the Common Shares will be duly
authorized, validly issued, fully paid and non-assessable.
<PAGE>
 
Lockheed Martin Corporation
May 11, 1999
Page 2

     The opinion expressed in this letter is limited to the matters set forth
herein, and no other opinions should be inferred beyond the matters expressly
stated.  This letter and the opinion expressed herein are being furnished to you
solely for your benefit and may not be relied upon, used, circulated, quoted
from or otherwise referred to by any other person or for any other purpose
without our prior written consent.

     We hereby consent to the filing of this letter as an exhibit to the
Registration Statement and to the reference to us under the heading "Legal
Matters" in the Proxy Statement/Prospectus contained therein.  In giving our
consent, we do not thereby admit that we are in the category of persons whose
consent is required under Section 7 of the Act or the rules and regulations of
the Securities and Exchange Commission thereunder.



                              Very truly yours,

                              /s/ King & Spalding

<PAGE>
 
                                                                     Exhibit 8.1

                 [LETTERHEAD OF KING & SPALDING APPEARS HERE]


                                May 11, 1999



Lockheed Martin Corporation
6801 Rockledge Drive
Bethesda, Maryland  20817

          Re:  Lockheed Martin Corporation
               Registration Statement on Form S-4
               ----------------------------------

Ladies and Gentlemen:

     We are acting as special tax counsel to Lockheed Martin Corporation, a
Maryland corporation ("Lockheed Martin"), in connection with the proposed merger
of COMSAT Corporation, a District of Columbia corporation ("COMSAT"), with and
into Deneb Corporation, a Delaware corporation and a wholly owned subsidiary of
Lockheed Martin ("Deneb"), or alternatively, the proposed merger of Deneb with
and into COMSAT (the "Merger"), pursuant to the Agreement and Plan of Merger,
dated as of September 18, 1998, among COMSAT, Lockheed Martin, and Deneb (the
"Merger Agreement"). You have requested our opinion regarding certain of the
United States federal income tax consequences of the Merger and the accuracy of
the discussion set forth under the heading "Material U.S. Federal Income Tax
Consequences" in the Proxy Statement/Prospectus (the "Prospectus"), which is
included in the Registration Statement on Form S-4 (the "Registration
Statement"), filed with the Securities and Exchange Commission (the
"Commission").

                    INFORMATION AND ASSUMPTIONS RELIED UPON
                    ---------------------------------------

     In rendering the opinion expressed in this letter, we have examined the
Merger Agreement, the Registration Statement (including the Prospectus and all
exhibits thereto), and such other documents as we have deemed necessary or
advisable. In our examination of the documents and in our reliance upon them in
issuing this opinion, we have assumed, with your consent, that all documents
submitted to us are authentic originals or, if submitted as photocopies or
telecopies, that they faithfully reproduce the originals thereof; that all such
documents submitted to us have been or will be duly executed and validly signed
(and filed, where applicable) to the extent required in substantially the same
form as they have been provided to us; that each executed document will
constitute the legal, valid, binding, and enforceable agreement of the signatory
parties; that all
<PAGE>
 
Lockheed Martin Corporation
May 11, 1999
Page 2                         


representations and statements set forth in such documents, which we have not
attempted to verify independently, are and will remain true, accurate, and
complete in all material respects; that the Merger and all related transactions
will be carried out in accordance with the terms and conditions of such
documents without the waiver or modification of any such terms and conditions;
and that all obligations imposed on, or covenants agreed to by, the parties
pursuant to any of such documents have been or will be performed or satisfied in
accordance with their terms in all material respects. We also have assumed that
the Merger qualifies as a statutory merger under applicable state law.
Furthermore, we have assumed that you have disclosed to us all of the documents
that are relevant to the transactions that are the subject of this opinion.

                                    OPINION
                                    -------

     Based upon and subject to the foregoing, it is our opinion that, although
the discussion set forth under the heading "Material U.S. Federal Income Tax
Consequences" in the Prospectus does not purport to discuss all possible United
States federal income tax consequences of the Merger to COMSAT shareholders who
surrender shares of COMSAT common stock pursuant to the Merger, such discussion
constitutes, in all material respects, a fair and accurate summary of the United
States federal income tax consequences of the Merger that are likely to be
material to such shareholders who hold shares of COMSAT common stock as capital
assets and who are not subject to special rules under the Internal Revenue Code
of 1986, as amended, or do not otherwise have unique individual circumstances.

     Our opinion is expressed as of the date hereof and is based upon existing
statutory, regulatory, administrative, and judicial authority and guidance in
effect as of the date hereof, any of which may be changed at any time, possibly
with retroactive effect. A change in any of the authorities or guidance upon
which our opinion is based could affect our conclusions. In addition, our
opinion is based solely on the documents that we have examined, the additional
information that we have obtained, and the statements, assumptions, and
representations referred to herein that we have assumed with your consent to be
true, accurate, and complete on the date hereof and at the time the Merger
becomes effective. Our opinion cannot be relied upon if any of the material
facts contained in such documents or such additional information, statements,
assumptions, or representations referred to herein is, or later becomes,
inaccurate. We disclaim any undertaking to advise you of any subsequent change
in the facts stated, referenced, or assumed herein or any subsequent change in
the authorities or guidance upon which our opinion is based. Our opinion
represents our legal judgment and has no official status of any kind.
Accordingly, we cannot assure you that the Internal Revenue Service or a court
having jurisdiction over the issue will agree with our opinion.

     Finally, our opinion is limited to the tax matters specifically addressed
herein, and no other opinions should be inferred beyond the matters expressly
stated. We have not been asked to address, nor have we addressed, any other tax
consequences of the Merger,
<PAGE>
 
Lockheed Martin Corporation
May 11, 1999
Page 3                         

including, but not limited to, any other federal, state, local, foreign,
transfer, sales, or use tax consequences, or any tax consequences of any other
transactions or events contemplated by or referred to in the Merger Agreement or
the Registration Statement.

     We hereby consent to the filing of this letter with the Commission as an
exhibit to the Registration Statement, and we consent to the reference to us
under the heading "Material U.S. Federal Income Tax Consequences" in the
Prospectus. In giving our consent, we do not thereby admit that we are in the
category of persons whose consent is required under Section 7 of the Securities
Act of 1933, as amended, or the rules and regulations of the Commission
thereunder. Except as set forth above, this opinion is not to be used,
circulated, quoted from, or otherwise referred to for any purpose without our
prior written consent.


                                              Very truly yours,



                                              /s/ King & Spalding

<PAGE>
 
                                                                     Exhibit 8.2
 
            [Letterhead of Skadden, Arps, Slate, Meagher & Flom LLP]



                                 May 11, 1999



COMSAT Corporation
6560 Rock Spring Drive
Bethesda, MD  20817


          Re:  Registration Statement on Form S-4
               ----------------------------------

Ladies and Gentlemen:

          We are acting as counsel to COMSAT corporation, a District of Columbia
corporation ("COMSAT"), in connection with the proposed merger (the "Merger") of
COMSAT with and into Deneb Corporation, a Delaware corporation ("Deneb"), a
wholly owned subsidiary of Lockheed Martin Corporation, a Maryland corporation
("Lockheed Martin"), or alternatively, the merger of Deneb with and into COMSAT,
pursuant to the Agreement and Plan of Merger, dated as of September 18, 1998,
among COMSAT, Lockheed Martin and Deneb (the "Merger Agreement"), as amended
through the date hereof.  You have requested our opinion concerning certain
United States federal income tax consequences of the Merger and the accuracy of
the discussion contained under the caption "Material U.S. Federal Income Tax
Consequences" in the Proxy Statement/Prospectus (the "Prospectus"), which is
included in the Registration Statement on Form S-4 (the "Registration 
Statement"), filed with the Securities and Exchange Commission (the
"Commission").
<PAGE>
 
COMSAT Corporation
May 11, 1999
Page 2


          In rendering our opinion, we have examined and relied upon the
accuracy and completeness of the facts, information, representations, and
covenants contained in originals or copies, certified or otherwise identified to
our satisfaction, of the Merger Agreement, the Prospectus and all exhibits
thereto, the Registration Statement and such other documents as we have deemed
necessary or appropriate as a basis for the opinion set forth below.  In our
examination of these documents and in our reliance upon them in issuing this
opinion, we have assumed, with your consent,  the genuineness of all signatures,
the legal capacity of natural persons, the authenticity of all documents
submitted to us as originals, the conformity to original documents of all
documents submitted to us as certified or photostatic copies, and the
authenticity of the originals of such documents.  We have assumed that each
executed document constitutes the legal, valid, binding and enforceable
agreement of the signatory parties; that all representations and statements set
forth in such documents are and will remain true, accurate and complete in all
material respects; that all of the transactions related to the merger will be
consummated in accordance with the terms of such documents; and that all
obligations imposed on, or covenants agreed to by, the parties pursuant to any
of such documents have been or will be performed or satisfied in accordance with
their terms in all material respects.  We have further assumed that the Merger
will be consummated pursuant to the terms and conditions set forth in the Merger
Agreement without the waiver or modification of any such terms and conditions
and that the Merger qualifies as a statutory merger under applicable state law.
We have not attempted to verify independently any representations and have
assumed that all representations contained in the documents are, and at the time
the Merger becomes effective will be, true, accurate and complete in all
material respects.  We have further assumed that you have disclosed to us all of
the documents that are relevant to the transactions that are the subject of this
opinion.

          In rendering our opinion, we have considered the applicable provisions
of the Internal Revenue Code of 1986, as amended (the "Code"), Treasury
regulations promulgated thereunder, pertinent judicial authorities, interpretive
rulings of the Internal Revenue Service, and such other authorities as we have
considered relevant, all of which are potentially subject to change, possibly
with retroactive effect.  A change in any of the authorities upon which our
opinion is based could affect our conclusions.
<PAGE>
 
COMSAT Corporation
May 11, 1999
Page 3

          Based on and subject to the foregoing, we are of the opinion that,
although the discussion set forth in the Registration Statement under the
caption "Material U.S. Federal Income Tax Consequences" does not purport to
discuss all possible United States federal income tax consequences of the Merger
to COMSAT shareholders who surrender shares of COMSAT common stock pursuant to
the Merger, such discussion constitutes, in all material respects, a fair and
accurate summary of the United States federal income tax consequences that are
likely to be material to such shareholders who hold shares of COMSAT common
stock as capital assets and who are not subject to special rules under the Code,
or do not otherwise have unique individual circumstances.

          Except as set forth above, we express no opinion to any party as to
any tax consequences, whether federal, state, local or foreign, of any
transactions or events contemplated by or referred to in the Merger Agreement or
the Registration Statement.  This opinion is expressed as of the date hereof,
unless otherwise expressly stated, and we disclaim any undertaking to advise you
of any subsequent changes of the facts stated, referenced, or assumed herein or
any subsequent changes in applicable law.

          This opinion is being provided in connection with the filing of the
Registration Statement. We acknowledge that you will rely on this opinion in
providing disclosure to the COMSAT shareholders of the material U.S. federal
income tax consequences of the merger. In addition, we consent to the use of our
name in the Prospectus under the heading "Material U.S. Federal Income Tax
Consequences" and to the filing of this opinion with the Commission as an
exhibit to the Registration Statement. In giving this consent, we do not thereby
admit that we are within the category of persons whose consent is required under
Section 7 of the Securities Act of 1933, as amended, or the rules and
regulations of the Commission promulgated thereunder. Except as set forth above,
this opinion is not to be used, circulated, quoted or otherwise referred to for
any purpose without our prior written consent.

                              Sincerely yours,

                              /s/ SKADDEN, ARPS, SLATE, MEAGHER & FLOM LLP

<PAGE>
 
                                                                    Exhibit 23.1
 
              CONSENT OF ERNST & YOUNG LLP, INDEPENDENT AUDITORS

We consent to the reference to our firm under the caption "Experts" included in
the Proxy Statement/Prospectus of COMSAT Corporation that is made a part of the
Registration Statement of Lockheed Martin Corporation on Form S-4, and to the
incorporation by reference therein of our report dated January 22, 1999, except
for the third paragraph of Note 4, as to which the date is February 11, 1999,
with respect to the consolidated financial statements of Lockheed Martin
Corporation incorporated by reference in its Annual Report (Form 10-K) for the
year ended December 31, 1998, filed with the Securities and Exchange Commission.



                                                     /s/ Ernst & Young LLP


Washington, D.C.
May 5, 1999

<PAGE>
 
                                                                    Exhibit 23.2

INDEPENDENT AUDITORS' CONSENT

We consent to the incorporation by reference in this Registration Statement of 
Lockheed Martin on Form S-4 of the report of Deloitte & Touche LLP dated 
February 18, 1999 appearing in the Annual Report on Form 10-K of COMSAT 
Corporation for the year ended December 31, 1998 and the reference to Deloitte &
Touche LLP under the heading "Experts" in the Prospectus, which is part of this
Registration Statement.


Washington, D.C.
May 11, 1999


<PAGE>
 
                                                                    Exhibit 23.5

                    CONSENT OF DONALDSON, LUFKIN & JENRETTE
                            SECURITIES CORPORATION



     We hereby consent to (i) the inclusion of our opinion letter, dated
September 18, 1998, to the Board of Directors of COMSAT Corporation (the
"Company") as Appendix III to the Proxy Statement/Prospectus of the Company
relating to the proposed acquisition of the Company by Lockheed Martin
Corporation, and (ii) all references to Donaldson, Lufkin & Jenrette Securities
Corporation in the sections captioned "Summary", "Background of the Merger",
"Recommendations of the COMSAT Board of Directors; Reasons for the Merger", and
"Opinion of COMSAT's Financial Advisor" of the Proxy Statement/Prospectus of the
Company which forms a part of this Registration Statement on Form S-4.  In
giving such consent, we do not admit that we come within the category of persons
whose consent is required under, and we do not admit that we are "experts" for
purposes of, the Securities Act of 1933, as amended, and the rules and
regulations promulgated thereunder.


                                        DONALDSON, LUFKIN & JENRETTE
                                        SECURITIES CORPORATION


                                        By: /s/ Douglas V. Brown
                                           ---------------------------------
                                           Name: Douglas V. Brown
                                           Title:Managing Director



New York, New York
May 11, 1999
- ------  

<PAGE>
 
                                                                    Exhibit 24.1


                               POWER OF ATTORNEY

                          LOCKHEED MARTIN CORPORATION

     The undersigned hereby constitutes Frank H. Menaker, Jr., Marian S. Block
and Stephen M. Piper, and each of them, jointly and severally, his or her lawful
attorney-in-fact and agent, with full power of substitution and resubstitution,
for him or her and in his or her name, place and stead, in any and all
capacities, including, but not limited to, that listed below, to execute and
file, or cause to be filed, with exhibits thereto and other documents in
connection therewith, with the Securities and Exchange Commission (hereinafter
referred to as the "Commission") one or more registration statements on Form S-4
for the purpose of registering under the Securities Act of 1933, as amended (the
"Securities Act"), securities of Lockheed Martin Corporation in connection with
the acquisition by Lockheed Martin Corporation (acting in conjunction with its
wholly owned subsidiary, Deneb Corporation) of COMSAT Corporation and amendments
thereto (including post-effective amendments), and all matters required by the
Commission in connection with such registration statements under the Securities
Act, granting unto said attorneys-in-fact and agents, and each of them, full
power and authority to do and perform each and every act and thing requisite or
necessary to be done as fully to all intents and purposes as he or she might or
could do in person, hereby ratifying and confirming all that said attorneys-in-
fact and agents, and each of them, or his substitute or substitutes, may
lawfully do or cause to be done by virtue hereof.


/s/ Vance D. Coffman                               April 22, 1999
- --------------------                                             
Vance D. Coffman
Chairman and Chief Executive Officer
<PAGE>
 
                               POWER OF ATTORNEY

                          LOCKHEED MARTIN CORPORATION

          The undersigned hereby constitutes Frank H. Menaker, Jr., Marian S.
Block and Stephen M. Piper, and each of them, jointly and severally, his or her
lawful attorney-in-fact and agent, with full power of substitution and
resubstitution, for him or her and in his or her name, place and stead, in any
and all capacities, including, but not limited to, that listed below, to execute
and file, or cause to be filed, with exhibits thereto and other documents in
connection therewith, with the Securities and Exchange Commission (hereinafter
referred to as the "Commission") one or more registration statements on Form S-4
for the purpose of registering under the Securities Act of 1933, as amended (the
"Securities Act"), securities of Lockheed Martin Corporation in connection with
the acquisition by Lockheed Martin Corporation (acting in conjunction with its
wholly owned subsidiary, Deneb Corporation) of COMSAT Corporation and amendments
thereto (including post-effective amendments), and all matters required by the
Commission in connection with such registration statements under the Securities
Act, granting unto said attorneys-in-fact and agents, and each of them, full
power and authority to do and perform each and every act and thing requisite or
necessary to be done as fully to all intents and purposes as he or she might or
could do in person, hereby ratifying and confirming all that said attorneys-in-
fact and agents, and each of them, or his substitute or substitutes, may
lawfully do or cause to be done by virtue hereof.


/s/ Philip J. Duke                                 April 22, 1999
- ------------------                                               
Philip J. Duke
Vice President and Chief Financial Officer
<PAGE>
 
                               POWER OF ATTORNEY

                          LOCKHEED MARTIN CORPORATION

          The undersigned hereby constitutes Frank H. Menaker, Jr., Marian S.
Block and Stephen M. Piper, and each of them, jointly and severally, his or her
lawful attorney-in-fact and agent, with full power of substitution and
resubstitution, for him or her and in his or her name, place and stead, in any
and all capacities, including, but not limited to, that listed below, to execute
and file, or cause to be filed, with exhibits thereto and other documents in
connection therewith, with the Securities and Exchange Commission (hereinafter
referred to as the "Commission") one or more registration statements on Form S-4
for the purpose of registering under the Securities Act of 1933, as amended (the
"Securities Act"), securities of Lockheed Martin Corporation in connection with
the acquisition by Lockheed Martin Corporation (acting in conjunction with its
wholly owned subsidiary, Deneb Corporation) of COMSAT Corporation and amendments
thereto (including post-effective amendments), and all matters required by the
Commission in connection with such registration statements under the Securities
Act, granting unto said attorneys-in-fact and agents, and each of them, full
power and authority to do and perform each and every act and thing requisite or
necessary to be done as fully to all intents and purposes as he or she might or
could do in person, hereby ratifying and confirming all that said attorneys-in-
fact and agents, and each of them, or his substitute or substitutes, may
lawfully do or cause to be done by virtue hereof.


/s/ Todd J. Kallman                                April 22, 1999
- -------------------                                              
Todd J. Kallman
Vice President and Chief Accounting Officer
<PAGE>
 
                               POWER OF ATTORNEY

                          LOCKHEED MARTIN CORPORATION

          The undersigned hereby constitutes Frank H. Menaker, Jr., Marian S.
Block and Stephen M. Piper, and each of them, jointly and severally, his or her
lawful attorney-in-fact and agent, with full power of substitution and
resubstitution, for him or her and in his or her name, place and stead, in any
and all capacities, including, but not limited to, that listed below, to execute
and file, or cause to be filed, with exhibits thereto and other documents in
connection therewith, with the Securities and Exchange Commission (hereinafter
referred to as the "Commission") one or more registration statements on Form S-4
for the purpose of registering under the Securities Act of 1933, as amended (the
"Securities Act"), securities of Lockheed Martin Corporation in connection with
the acquisition by Lockheed Martin Corporation (acting in conjunction with its
wholly owned subsidiary, Deneb Corporation) of COMSAT Corporation and amendments
thereto (including post-effective amendments), and all matters required by the
Commission in connection with such registration statements under the Securities
Act, granting unto said attorneys-in-fact and agents, and each of them, full
power and authority to do and perform each and every act and thing requisite or
necessary to be done as fully to all intents and purposes as he or she might or
could do in person, hereby ratifying and confirming all that said attorneys-in-
fact and agents, and each of them, or his substitute or substitutes, may
lawfully do or cause to be done by virtue hereof.


/s/ Norman R. Augustine                            April 22, 1999
- -----------------------                                          
Norman R. Augustine
Director
<PAGE>
 
                               POWER OF ATTORNEY

                          LOCKHEED MARTIN CORPORATION

          The undersigned hereby constitutes Frank H. Menaker, Jr., Marian S.
Block and Stephen M. Piper, and each of them, jointly and severally, his or her
lawful attorney-in-fact and agent, with full power of substitution and
resubstitution, for him or her and in his or her name, place and stead, in any
and all capacities, including, but not limited to, that listed below, to execute
and file, or cause to be filed, with exhibits thereto and other documents in
connection therewith, with the Securities and Exchange Commission (hereinafter
referred to as the "Commission") one or more registration statements on Form S-4
for the purpose of registering under the Securities Act of 1933, as amended (the
"Securities Act"), securities of Lockheed Martin Corporation in connection with
the acquisition by Lockheed Martin Corporation (acting in conjunction with its
wholly owned subsidiary, Deneb Corporation) of COMSAT Corporation and amendments
thereto (including post-effective amendments), and all matters required by the
Commission in connection with such registration statements under the Securities
Act, granting unto said attorneys-in-fact and agents, and each of them, full
power and authority to do and perform each and every act and thing requisite or
necessary to be done as fully to all intents and purposes as he or she might or
could do in person, hereby ratifying and confirming all that said attorneys-in-
fact and agents, and each of them, or his substitute or substitutes, may
lawfully do or cause to be done by virtue hereof.


/s/ Marcus C. Bennett                              April 22, 1999
- ---------------------                                            
Marcus C. Bennett
Director
<PAGE>
 
                               POWER OF ATTORNEY

                          LOCKHEED MARTIN CORPORATION

          The undersigned hereby constitutes Frank H. Menaker, Jr., Marian S.
Block and Stephen M. Piper, and each of them, jointly and severally, his or her
lawful attorney-in-fact and agent, with full power of substitution and
resubstitution, for him or her and in his or her name, place and stead, in any
and all capacities, including, but not limited to, that listed below, to execute
and file, or cause to be filed, with exhibits thereto and other documents in
connection therewith, with the Securities and Exchange Commission (hereinafter
referred to as the "Commission") one or more registration statements on Form S-4
for the purpose of registering under the Securities Act of 1933, as amended (the
"Securities Act"), securities of Lockheed Martin Corporation in connection with
the acquisition by Lockheed Martin Corporation (acting in conjunction with its
wholly owned subsidiary, Deneb Corporation) of COMSAT Corporation and amendments
thereto (including post-effective amendments), and all matters required by the
Commission in connection with such registration statements under the Securities
Act, granting unto said attorneys-in-fact and agents, and each of them, full
power and authority to do and perform each and every act and thing requisite or
necessary to be done as fully to all intents and purposes as he or she might or
could do in person, hereby ratifying and confirming all that said attorneys-in-
fact and agents, and each of them, or his substitute or substitutes, may
lawfully do or cause to be done by virtue hereof.


/s/ Lynne V. Cheney                                April 22, 1999
- -------------------                                              
Lynne V. Cheney
Director
<PAGE>
 
                               POWER OF ATTORNEY

                          LOCKHEED MARTIN CORPORATION

          The undersigned hereby constitutes Frank H. Menaker, Jr., Marian S.
Block and Stephen M. Piper, and each of them, jointly and severally, his or her
lawful attorney-in-fact and agent, with full power of substitution and
resubstitution, for him or her and in his or her name, place and stead, in any
and all capacities, including, but not limited to, that listed below, to execute
and file, or cause to be filed, with exhibits thereto and other documents in
connection therewith, with the Securities and Exchange Commission (hereinafter
referred to as the "Commission") one or more registration statements on Form S-4
for the purpose of registering under the Securities Act of 1933, as amended (the
"Securities Act"), securities of Lockheed Martin Corporation in connection with
the acquisition by Lockheed Martin Corporation (acting in conjunction with its
wholly owned subsidiary, Deneb Corporation) of COMSAT Corporation and amendments
thereto (including post-effective amendments), and all matters required by the
Commission in connection with such registration statements under the Securities
Act, granting unto said attorneys-in-fact and agents, and each of them, full
power and authority to do and perform each and every act and thing requisite or
necessary to be done as fully to all intents and purposes as he or she might or
could do in person, hereby ratifying and confirming all that said attorneys-in-
fact and agents, and each of them, or his substitute or substitutes, may
lawfully do or cause to be done by virtue hereof.


/s/ Houston I. Flournoy                            April 22, 1999
- -----------------------                                          
Houston I. Flournoy
Director
<PAGE>
 
                               POWER OF ATTORNEY

                          LOCKHEED MARTIN CORPORATION

          The undersigned hereby constitutes Frank H. Menaker, Jr., Marian S.
Block and Stephen M. Piper, and each of them, jointly and severally, his or her
lawful attorney-in-fact and agent, with full power of substitution and
resubstitution, for him or her and in his or her name, place and stead, in any
and all capacities, including, but not limited to, that listed below, to execute
and file, or cause to be filed, with exhibits thereto and other documents in
connection therewith, with the Securities and Exchange Commission (hereinafter
referred to as the "Commission") one or more registration statements on Form S-4
for the purpose of registering under the Securities Act of 1933, as amended (the
"Securities Act"), securities of Lockheed Martin Corporation in connection with
the acquisition by Lockheed Martin Corporation (acting in conjunction with its
wholly owned subsidiary, Deneb Corporation) of COMSAT Corporation and amendments
thereto (including post-effective amendments), and all matters required by the
Commission in connection with such registration statements under the Securities
Act, granting unto said attorneys-in-fact and agents, and each of them, full
power and authority to do and perform each and every act and thing requisite or
necessary to be done as fully to all intents and purposes as he or she might or
could do in person, hereby ratifying and confirming all that said attorneys-in-
fact and agents, and each of them, or his substitute or substitutes, may
lawfully do or cause to be done by virtue hereof.


/s/ James F. Gibbons                               April 22, 1999
- --------------------                                             
James F. Gibbons
Director
<PAGE>
 
                               POWER OF ATTORNEY

                          LOCKHEED MARTIN CORPORATION

          The undersigned hereby constitutes Frank H. Menaker, Jr., Marian S.
Block and Stephen M. Piper, and each of them, jointly and severally, his or her
lawful attorney-in-fact and agent, with full power of substitution and
resubstitution, for him or her and in his or her name, place and stead, in any
and all capacities, including, but not limited to, that listed below, to execute
and file, or cause to be filed, with exhibits thereto and other documents in
connection therewith, with the Securities and Exchange Commission (hereinafter
referred to as the "Commission") one or more registration statements on Form S-4
for the purpose of registering under the Securities Act of 1933, as amended (the
"Securities Act"), securities of Lockheed Martin Corporation in connection with
the acquisition by Lockheed Martin Corporation (acting in conjunction with its
wholly owned subsidiary, Deneb Corporation) of COMSAT Corporation and amendments
thereto (including post-effective amendments), and all matters required by the
Commission in connection with such registration statements under the Securities
Act, granting unto said attorneys-in-fact and agents, and each of them, full
power and authority to do and perform each and every act and thing requisite or
necessary to be done as fully to all intents and purposes as he or she might or
could do in person, hereby ratifying and confirming all that said attorneys-in-
fact and agents, and each of them, or his substitute or substitutes, may
lawfully do or cause to be done by virtue hereof.


/s/ Edward E. Hood, Jr.                            April 22, 1999
- -----------------------                                          
Edward E. Hood, Jr.
Director
<PAGE>
 
                               POWER OF ATTORNEY

                          LOCKHEED MARTIN CORPORATION

          The undersigned hereby constitutes Frank H. Menaker, Jr., Marian S.
Block and Stephen M. Piper, and each of them, jointly and severally, his or her
lawful attorney-in-fact and agent, with full power of substitution and
resubstitution, for him or her and in his or her name, place and stead, in any
and all capacities, including, but not limited to, that listed below, to execute
and file, or cause to be filed, with exhibits thereto and other documents in
connection therewith, with the Securities and Exchange Commission (hereinafter
referred to as the "Commission") one or more registration statements on Form S-4
for the purpose of registering under the Securities Act of 1933, as amended (the
"Securities Act"), securities of Lockheed Martin Corporation in connection with
the acquisition by Lockheed Martin Corporation (acting in conjunction with its
wholly owned subsidiary, Deneb Corporation) of COMSAT Corporation and amendments
thereto (including post-effective amendments), and all matters required by the
Commission in connection with such registration statements under the Securities
Act, granting unto said attorneys-in-fact and agents, and each of them, full
power and authority to do and perform each and every act and thing requisite or
necessary to be done as fully to all intents and purposes as he or she might or
could do in person, hereby ratifying and confirming all that said attorneys-in-
fact and agents, and each of them, or his substitute or substitutes, may
lawfully do or cause to be done by virtue hereof.


/s/ Caleb B. Hurtt                                 April 22, 1999
- ------------------                                               
Caleb B. Hurtt
Director
<PAGE>
 
                               POWER OF ATTORNEY

                          LOCKHEED MARTIN CORPORATION

          The undersigned hereby constitutes Frank H. Menaker, Jr., Marian S.
Block and Stephen M. Piper, and each of them, jointly and severally, his or her
lawful attorney-in-fact and agent, with full power of substitution and
resubstitution, for him or her and in his or her name, place and stead, in any
and all capacities, including, but not limited to, that listed below, to execute
and file, or cause to be filed, with exhibits thereto and other documents in
connection therewith, with the Securities and Exchange Commission (hereinafter
referred to as the "Commission") one or more registration statements on Form S-4
for the purpose of registering under the Securities Act of 1933, as amended (the
"Securities Act"), securities of Lockheed Martin Corporation in connection with
the acquisition by Lockheed Martin Corporation (acting in conjunction with its
wholly owned subsidiary, Deneb Corporation) of COMSAT Corporation and amendments
thereto (including post-effective amendments), and all matters required by the
Commission in connection with such registration statements under the Securities
Act, granting unto said attorneys-in-fact and agents, and each of them, full
power and authority to do and perform each and every act and thing requisite or
necessary to be done as fully to all intents and purposes as he or she might or
could do in person, hereby ratifying and confirming all that said attorneys-in-
fact and agents, and each of them, or his substitute or substitutes, may
lawfully do or cause to be done by virtue hereof.


/s/ Gwendolyn S. King                              April 22, 1999
- ---------------------                                            
Gwendolyn S. King
Director
<PAGE>
 
                               POWER OF ATTORNEY

                          LOCKHEED MARTIN CORPORATION

          The undersigned hereby constitutes Frank H. Menaker, Jr., Marian S.
Block and Stephen M. Piper, and each of them, jointly and severally, his or her
lawful attorney-in-fact and agent, with full power of substitution and
resubstitution, for him or her and in his or her name, place and stead, in any
and all capacities, including, but not limited to, that listed below, to execute
and file, or cause to be filed, with exhibits thereto and other documents in
connection therewith, with the Securities and Exchange Commission (hereinafter
referred to as the "Commission") one or more registration statements on Form S-4
for the purpose of registering under the Securities Act of 1933, as amended (the
"Securities Act"), securities of Lockheed Martin Corporation in connection with
the acquisition by Lockheed Martin Corporation (acting in conjunction with its
wholly owned subsidiary, Deneb Corporation) of COMSAT Corporation and amendments
thereto (including post-effective amendments), and all matters required by the
Commission in connection with such registration statements under the Securities
Act, granting unto said attorneys-in-fact and agents, and each of them, full
power and authority to do and perform each and every act and thing requisite or
necessary to be done as fully to all intents and purposes as he or she might or
could do in person, hereby ratifying and confirming all that said attorneys-in-
fact and agents, and each of them, or his substitute or substitutes, may
lawfully do or cause to be done by virtue hereof.


/s/ Eugene F. Murphy                               April 22, 1999
- --------------------                                             
Eugene F. Murphy
Director
<PAGE>
 
                               POWER OF ATTORNEY

                          LOCKHEED MARTIN CORPORATION

          The undersigned hereby constitutes Frank H. Menaker, Jr., Marian S.
Block and Stephen M. Piper, and each of them, jointly and severally, his or her
lawful attorney-in-fact and agent, with full power of substitution and
resubstitution, for him or her and in his or her name, place and stead, in any
and all capacities, including, but not limited to, that listed below, to execute
and file, or cause to be filed, with exhibits thereto and other documents in
connection therewith, with the Securities and Exchange Commission (hereinafter
referred to as the "Commission") one or more registration statements on Form S-4
for the purpose of registering under the Securities Act of 1933, as amended (the
"Securities Act"), securities of Lockheed Martin Corporation in connection with
the acquisition by Lockheed Martin Corporation (acting in conjunction with its
wholly owned subsidiary, Deneb Corporation) of COMSAT Corporation and amendments
thereto (including post-effective amendments), and all matters required by the
Commission in connection with such registration statements under the Securities
Act, granting unto said attorneys-in-fact and agents, and each of them, full
power and authority to do and perform each and every act and thing requisite or
necessary to be done as fully to all intents and purposes as he or she might or
could do in person, hereby ratifying and confirming all that said attorneys-in-
fact and agents, and each of them, or his substitute or substitutes, may
lawfully do or cause to be done by virtue hereof.


/s/ Frank Savage                                   April 22, 1999
- ----------------                                                 
Frank Savage
Director
<PAGE>
 
                               POWER OF ATTORNEY

                          LOCKHEED MARTIN CORPORATION

          The undersigned hereby constitutes Frank H. Menaker, Jr., Marian S.
Block and Stephen M. Piper, and each of them, jointly and severally, his or her
lawful attorney-in-fact and agent, with full power of substitution and
resubstitution, for him or her and in his or her name, place and stead, in any
and all capacities, including, but not limited to, that listed below, to execute
and file, or cause to be filed, with exhibits thereto and other documents in
connection therewith, with the Securities and Exchange Commission (hereinafter
referred to as the "Commission") one or more registration statements on Form S-4
for the purpose of registering under the Securities Act of 1933, as amended (the
"Securities Act"), securities of Lockheed Martin Corporation in connection with
the acquisition by Lockheed Martin Corporation (acting in conjunction with its
wholly owned subsidiary, Deneb Corporation) of COMSAT Corporation and amendments
thereto (including post-effective amendments), and all matters required by the
Commission in connection with such registration statements under the Securities
Act, granting unto said attorneys-in-fact and agents, and each of them, full
power and authority to do and perform each and every act and thing requisite or
necessary to be done as fully to all intents and purposes as he or she might or
could do in person, hereby ratifying and confirming all that said attorneys-in-
fact and agents, and each of them, or his substitute or substitutes, may
lawfully do or cause to be done by virtue hereof.


/s/ Peter B. Teets                                 April 22, 1999
- ------------------                                               
Peter B. Teets
Director and Chief Operating Officer
<PAGE>
 
                               POWER OF ATTORNEY

                          LOCKHEED MARTIN CORPORATION

          The undersigned hereby constitutes Frank H. Menaker, Jr., Marian S.
Block and Stephen M. Piper, and each of them, jointly and severally, his or her
lawful attorney-in-fact and agent, with full power of substitution and
resubstitution, for him or her and in his or her name, place and stead, in any
and all capacities, including, but not limited to, that listed below, to execute
and file, or cause to be filed, with exhibits thereto and other documents in
connection therewith, with the Securities and Exchange Commission (hereinafter
referred to as the "Commission") one or more registration statements on Form S-4
for the purpose of registering under the Securities Act of 1933, as amended (the
"Securities Act"), securities of Lockheed Martin Corporation in connection with
the acquisition by Lockheed Martin Corporation (acting in conjunction with its
wholly owned subsidiary, Deneb Corporation) of COMSAT Corporation and amendments
thereto (including post-effective amendments), and all matters required by the
Commission in connection with such registration statements under the Securities
Act, granting unto said attorneys-in-fact and agents, and each of them, full
power and authority to do and perform each and every act and thing requisite or
necessary to be done as fully to all intents and purposes as he or she might or
could do in person, hereby ratifying and confirming all that said attorneys-in-
fact and agents, and each of them, or his substitute or substitutes, may
lawfully do or cause to be done by virtue hereof.


/s/ Carlisle A. H. Trost                           April 22, 1999
- ------------------------                                         
Carlisle A.H. Trost
Director
<PAGE>
 
                               POWER OF ATTORNEY

                          LOCKHEED MARTIN CORPORATION

          The undersigned hereby constitutes Frank H. Menaker, Jr., Marian S.
Block and Stephen M. Piper, and each of them, jointly and severally, his or her
lawful attorney-in-fact and agent, with full power of substitution and
resubstitution, for him or her and in his or her name, place and stead, in any
and all capacities, including, but not limited to, that listed below, to execute
and file, or cause to be filed, with exhibits thereto and other documents in
connection therewith, with the Securities and Exchange Commission (hereinafter
referred to as the "Commission") one or more registration statements on Form S-4
for the purpose of registering under the Securities Act of 1933, as amended (the
"Securities Act"), securities of Lockheed Martin Corporation in connection with
the acquisition by Lockheed Martin Corporation (acting in conjunction with its
wholly owned subsidiary, Deneb Corporation) of COMSAT Corporation and amendments
thereto (including post-effective amendments), and all matters required by the
Commission in connection with such registration statements under the Securities
Act, granting unto said attorneys-in-fact and agents, and each of them, full
power and authority to do and perform each and every act and thing requisite or
necessary to be done as fully to all intents and purposes as he or she might or
could do in person, hereby ratifying and confirming all that said attorneys-in-
fact and agents, and each of them, or his substitute or substitutes, may
lawfully do or cause to be done by virtue hereof.


/s/ James R. Ukropina                              April 22, 1999
- ---------------------                                            
James R. Ukropina
Director
<PAGE>
 
                               POWER OF ATTORNEY

                          LOCKHEED MARTIN CORPORATION

          The undersigned hereby constitutes Frank H. Menaker, Jr., Marian S.
Block and Stephen M. Piper, and each of them, jointly and severally, his or her
lawful attorney-in-fact and agent, with full power of substitution and
resubstitution, for him or her and in his or her name, place and stead, in any
and all capacities, including, but not limited to, that listed below, to execute
and file, or cause to be filed, with exhibits thereto and other documents in
connection therewith, with the Securities and Exchange Commission (hereinafter
referred to as the "Commission") one or more registration statements on Form S-4
for the purpose of registering under the Securities Act of 1933, as amended (the
"Securities Act"), securities of Lockheed Martin Corporation in connection with
the acquisition by Lockheed Martin Corporation (acting in conjunction with its
wholly owned subsidiary, Deneb Corporation) of COMSAT Corporation and amendments
thereto (including post-effective amendments), and all matters required by the
Commission in connection with such registration statements under the Securities
Act, granting unto said attorneys-in-fact and agents, and each of them, full
power and authority to do and perform each and every act and thing requisite or
necessary to be done as fully to all intents and purposes as he or she might or
could do in person, hereby ratifying and confirming all that said attorneys-in-
fact and agents, and each of them, or his substitute or substitutes, may
lawfully do or cause to be done by virtue hereof.


/s/ Douglas C. Yearley                             April 22, 1999
- ----------------------                                           
Douglas C. Yearley
Director


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