COMSAT CORP
S-3, 1995-06-02
COMMUNICATIONS SERVICES, NEC
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<PAGE>
      AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON JUNE 2, 1995

                                                       REGISTRATION NO. 33-
- - --------------------------------------------------------------------------------
- - --------------------------------------------------------------------------------
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                                ----------------
                                    FORM S-3
                             REGISTRATION STATEMENT
                                     UNDER
                           THE SECURITIES ACT OF 1933
                                 --------------

<TABLE>
<S>                                   <C>                                   <C>
       COMSAT CAPITAL I, L.P.               COMSAT CAPITAL II, L.P.                  COMSAT CORPORATION
    (Exact Name of Registrant as          (Exact Name of Registrant as          (Exact Name of Registrant as
    Specified in Certificate of           Specified in Certificate of              Specified in Charter)
        Limited Partnership)                  Limited Partnership)
              DELAWARE                              DELAWARE                        DISTRICT OF COLUMBIA
                         (State or Other Jurisdiction of Incorporation or Organization)
             52-1928675                            52-1928672                            52-0781863
                                      (I.R.S. Employer Identification No.)
       6560 ROCK SPRING DRIVE                6560 ROCK SPRING DRIVE                6560 ROCK SPRING DRIVE
         BETHESDA, MD 20817                    BETHESDA, MD 20817                    BETHESDA, MD 20817
           (301) 214-3000                        (301) 214-3000                        (301) 214-3000
</TABLE>

  (Address, Including Zip Code, and Telephone Number, Including Area Code, of
                   Registrants' Principal Executive Offices)

                             WARREN Y. ZEGER, ESQ.
                 VICE PRESIDENT, GENERAL COUNSEL AND SECRETARY
                               COMSAT CORPORATION
                             6560 ROCK SPRING DRIVE
                               BETHESDA, MD 20817
                                 (301) 214-3000
           (Name, Address, Including Zip Code, and Telephone Number,
                   Including Area Code, of Agent for Service)

                                WITH COPIES TO:

<TABLE>
<S>                                                      <C>
               William P. O'Neill, Esq.                               Robert E. Buckholz, Jr., Esq.
                   Crowell & Moring                                        Sullivan & Cromwell
            1001 Pennsylvania Avenue, N.W.                                  125 Broad Street
                Washington, D.C. 20004                                  New York, New York 10004
                    (202) 624-2500                                           (212) 558-4000
</TABLE>

    APPROXIMATE  DATE OF COMMENCEMENT OF PROPOSED  SALE TO THE PUBLIC: FROM TIME
TO TIME  AND/OR  AS  SOON  AS  PRACTICABLE AFTER  THE  EFFECTIVE  DATE  OF  THIS
REGISTRATION STATEMENT.
                                ----------------
    If  the  only securities  being registered  on this  Form are  being offered
pursuant to dividend or interest reinvestment plans, please check the  following
box. / /

    If  any of the securities being registered on this Form are to be offered on
a delayed or continuous basis pursuant to  Rule 415 under the Securities Act  of
1933, other than securities offered only in connection with dividend or interest
reinvestment plans, please check the following box. /X/
                                ----------------
                        CALCULATION OF REGISTRATION FEE

<TABLE>
<CAPTION>
                                                                    PROPOSED          PROPOSED
                                                                    MAXIMUM           MAXIMUM
               TITLE OF EACH                       AMOUNT        OFFERING PRICE      AGGREGATE         AMOUNT OF
            CLASS OF SECURITIES                    TO BE              PER             OFFERING        REGISTRATION
              BEING REGISTERED                 REGISTERED (1)    UNIT (1)(2)(3)   PRICE (1)(2)(3)       FEE (4)
<S>                                           <C>               <C>               <C>               <C>
COMSAT Capital I, L.P. Preferred Securities;
 COMSAT Capital II, L.P. Preferred
 Securities; COMSAT Corporation Junior
 Subordinated Deferrable Interest
 Debentures; COMSAT Corporation Guarantees
 with respect to Preferred Securities;
 COMSAT Corporation Common Stock, without
 par value..................................
Total.......................................    $200,000,000         $  --          $200,000,000       $68,965.52
<FN>
(1)  There are being registered hereunder Preferred Securities of COMSAT Capital
     I,  L.P.  and Preferred  Securities  of COMSAT  Capital  II, L.P.,  with an
     aggregate initial offering price not  to exceed $200,000,000 (of which  not
     more  than $100,000,000 may be Preferred Securities convertible into Common
     Stock of  COMSAT  Corporation),  Junior  Subordinated  Deferrable  Interest
     Debentures  of COMSAT Corporation  (which may be  distributed to holders of
     Preferred Securities upon a dissolution of COMSAT Capital I, L.P., and  for
     which  no  separate consideration  will  be received),  Junior Subordinated
     Deferrable  Interest  Debentures  of  COMSAT  Corporation  (which  may   be
     distributed to holders of Preferred Securities upon a dissolution of COMSAT
     Capital II, L.P., and for which no separate consideration will be received)
     and  such currently indeterminate number of shares of Common Stock, without
     par value, of  COMSAT Corporation  into which the  Preferred Securities  of
     COMSAT  Capital II, L.P. may be  converted (through the Junior Subordinated
     Debentures  of  COMSAT  Corporation).  There  are  also  being   registered
     hereunder  Guarantees of COMSAT Corporation in connection with the issuance
     of the Preferred Securities,  for which no  separate consideration will  be
     received.
(2)  Estimated solely for the purpose of determining the registration fee.
(3)  Exclusive of accrued interest and distributions, if any.
(4)  The  amount of the registration fee  has been calculated in accordance with
     Rule 457(i) and (n) under the Securities Act of 1933.
</TABLE>

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

    THE REGISTRANTS HEREBY  AMEND THIS  REGISTRATION STATEMENT ON  SUCH DATE  OR
DATES  AS MAY  BE NECESSARY  TO DELAY ITS  EFFECTIVE DATE  UNTIL THE REGISTRANTS
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>
EXPLANATORY NOTE

    This  Registration   Statement   contains   the   following   two   separate
prospectuses:

    1.   A form to be used in  connection with the offering by COMSAT Capital I,
L.P. of its Preferred Securities; and

    2.  A form to be used in connection with the offering by COMSAT Capital  II,
L.P.  of its Preferred Securities, which may be convertible into Common Stock of
COMSAT Corporation.

    The maximum aggregate offering price  of the Preferred Securities of  COMSAT
Capital I, L.P. and the Preferred Securities of COMSAT Capital II, L.P. will not
exceed  $200,000,000, of  which not  more than  $100,000,000 may  be Convertible
Preferred Securities of COMSAT Capital II, L.P.
<PAGE>
INFORMATION   CONTAINED  HEREIN  IS  SUBJECT   TO  COMPLETION  OR  AMENDMENT.  A
REGISTRATION STATEMENT  RELATING TO  THESE SECURITIES  HAS BEEN  FILED WITH  THE
SECURITIES  AND EXCHANGE  COMMISSION. THESE SECURITIES  MAY NOT BE  SOLD NOR MAY
OFFERS TO BUY BE ACCEPTED PRIOR  TO THE TIME THE REGISTRATION STATEMENT  BECOMES
EFFECTIVE.  THIS  PROSPECTUS  SHALL  NOT  CONSTITUTE AN  OFFER  TO  SELL  OR THE
SOLICITATION OF AN OFFER TO BUY NOR SHALL THERE BE ANY SALE OF THESE  SECURITIES
IN  ANY STATE IN WHICH SUCH OFFER,  SOLICITATION OR SALE WOULD BE UNLAWFUL PRIOR
TO REGISTRATION OR QUALIFICATION UNDER THE SECURITIES LAWS OF ANY SUCH STATE.
<PAGE>
                   SUBJECT TO COMPLETION, DATED JUNE 2, 1995

                                  PREFERRED SECURITIES
                                COMSAT CAPITAL I
           % CUMULATIVE MONTHLY INCOME PREFERRED SECURITIES (MIPS-SM-*)
              (LIQUIDATION PREFERENCE $25 PER PREFERRED SECURITY)
                  GUARANTEED TO THE EXTENT SET FORTH HEREIN BY
                           [LOGO] COMSAT CORPORATION
                                   ---------

    The                 % Cumulative  Monthly Income  Preferred Securities  (the
"Preferred  Securities")  representing  the  limited  partner  interests offered
hereby are being issued by COMSAT Capital I, L.P., a limited partnership  formed
under   the  laws  of  the  State  of  Delaware  ("COMSAT  Capital  I").  COMSAT
Corporation, a  District  of Columbia  corporation  ("COMSAT"), is  the  general
partner  in COMSAT Capital  I (in such capacity,  the "General Partner"). COMSAT
Capital I exists for  the sole purpose of  issuing the Preferred Securities  and
using  the proceeds thereof to purchase from  COMSAT its   % Junior Subordinated
Deferrable Interest Debentures  (the "Junior  Subordinated Debentures"),  having
the  terms described  herein. The limited  partner interests  represented by the
Preferred Securities will have a  preference with respect to cash  distributions
and amounts payable on liquidation over the General Partner's interest in COMSAT
Capital I.

                                                        (CONTINUED ON NEXT PAGE)
                                ----------------

    SEE  "RISK FACTORS"  ON PAGE  6 OF  THIS PROSPECTUS  FOR CERTAIN INFORMATION
RELEVANT TO AN INVESTMENT IN THE PREFERRED SECURITIES, INCLUDING THE PERIOD  AND
CIRCUMSTANCES  DURING AND UNDER  WHICH PAYMENTS ON  THE PREFERRED SECURITIES AND
JUNIOR SUBORDINATED DEBENTURES MAY  BE DEFERRED AND  THE RELATED FEDERAL  INCOME
TAX CONSEQUENCES.
                                 -------------

THESE  SECURITIES HAVE NOT BEEN APPROVED  OR DISAPPROVED BY THE SECURITIES AND
  EXCHANGE COMMISSION  OR  ANY  STATE  SECURITIES  COMMISSION  NOR  HAS  THE
    SECURITIES  AND EXCHANGE COMMISSION OR  ANY STATE SECURITIES COMMISSION
     PASSED  UPON   THE   ACCURACY   OR  ADEQUACY   OF   THIS   PROSPECTUS.
           ANY REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE.
                                 --------------

<TABLE>
<CAPTION>
                                                       INITIAL PUBLIC     UNDERWRITING          PROCEEDS TO
                                                       OFFERING PRICE    COMMISSION (1)   COMSAT CAPITAL I (2)(3)
                                                       ---------------  ----------------  ------------------------
<S>                                                    <C>              <C>               <C>
Per Preferred Security...............................      $25.00             (2)                  $25.00
Total................................................         $               (2)                    $
<FN>
- - ----------------
(1)  COMSAT   Capital  I  and  COMSAT  have  agreed  to  indemnify  the  several
     Underwriters against certain liabilities,  including liabilities under  the
     Securities Act of 1933, as amended. See "Underwriting".
(2)  In  view  of  the fact  that  the proceeds  of  the sale  of  the Preferred
     Securities will ultimately be  invested in Junior Subordinated  Debentures,
     the   Underwriting  Agreement  provides   that  COMSAT  will   pay  to  the
     Underwriters, as compensation for their arranging the investment therein of
     such proceeds, $      per Preferred Security (or $      in the  aggregate).
     See "Underwriting".
(3)  Expenses  of the offering which  are payable by COMSAT  are estimated to be
     $     .
</TABLE>

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

    The Preferred  Securities  offered  hereby  are  offered  severally  by  the
Underwriters, as specified herein, and subject to receipt and acceptance by them
and  subject to  their right  to reject  any order  in whole  or in  part. It is
expected that  delivery  of  the  Preferred Securities  will  be  made  only  in
book-entry  form through the facilities of DTC,  New York, New York, on or about
         , 1995.

- - ----------------
*MIPS is a servicemark of Goldman, Sachs & Co.

GOLDMAN, SACHS & CO.                                           SMITH BARNEY INC.
                                CS FIRST BOSTON
                                   ---------

                The date of this Prospectus is          , 1995.
<PAGE>
(CONTINUED FROM PREVIOUS PAGE)

    Holders of the Preferred Securities  will be entitled to receive  cumulative
cash distributions at an annual rate of   % of the liquidation preference of $25
per  Preferred Security, accruing from the date of original issuance and payable
monthly in  arrears  on the  last  day of  each  calendar month  of  each  year,
commencing             , 1995. See  "Description of the  Preferred Securities --
Dividends". The payment of dividends (but only if and to the extent declared out
of moneys held by COMSAT Capital I and legally available therefor), and payments
on liquidation of COMSAT Capital I or the redemption of Preferred Securities, as
set forth below, are  guaranteed by COMSAT to  the extent described herein  (the
"Guarantee").  COMSAT's  obligations  under the  Guarantee  are  subordinate and
junior in right  to all other  liabilities of COMSAT  (other than certain  other
guarantees).  See  "Description  of  the Guarantee".  If  COMSAT  fails  to make
interest payments on the Junior  Subordinated Debentures, COMSAT Capital I  will
have  insufficient  funds  to pay  dividends  on the  Preferred  Securities. The
Guarantee does not  cover payment of  dividends when COMSAT  Capital I does  not
have sufficient funds to pay such dividends.

    COMSAT  has the right under the Indenture (as defined herein) for the Junior
Subordinated Debentures to extend the interest payment period from time to  time
on  the Junior Subordinated Debentures to  a period not exceeding 60 consecutive
months, and, as  a consequence,  monthly dividends on  the Preferred  Securities
would  be  deferred by  COMSAT  Capital I  (but  would continue  to  accrue with
interest) during any such extended interest payment period. See "Risk Factors --
Option to  Extend  Interest  Payment  Period",  "Description  of  the  Preferred
Securities  -- Dividends" and "Description of the Junior Subordinated Debentures
- - -- Option to Extend Interest Payment Period".

    The Preferred Securities are redeemable at  the option of COMSAT Capital  I,
in  whole or in part, from time to time, on or after          , 2000, at $25 per
Preferred Security plus  accrued and  unpaid dividends thereon  (whether or  not
earned  or declared) to the date  fixed for redemption (the "Redemption Price").
See "Description of the Preferred  Securities -- Optional Redemption". Upon  the
repayment  of  the  Junior  Subordinated  Debentures  at  maturity  or  upon any
acceleration, earlier redemption or otherwise, the proceeds from such  repayment
will be applied to redeem the Preferred Securities.

    In  addition, upon the occurrence of certain events arising from a change in
law or a change in legal interpretation, the Preferred Securities are redeemable
in whole at the Redemption  Price at the option of  the General Partner, or  the
General Partner may dissolve COMSAT Capital I and cause to be distributed to the
holders  of the Preferred  Securities, on a pro  rata basis, Junior Subordinated
Debentures in  lieu  of  any  cash  distribution.  If  the  Junior  Subordinated
Debentures  are distributed to  the holders of  the Preferred Securities, COMSAT
will use its best efforts to  have the Junior Subordinated Debentures listed  on
the  New  York  Stock  Exchange  or on  such  other  exchange  as  the Preferred
Securities  are  then  listed.  The  obligations  of  COMSAT  under  the  Junior
Subordinated Debentures are subordinate and junior in right of payment to Senior
Indebtedness   (as  defined  herein)  of  COMSAT.  At  March  31,  1995,  Senior
Indebtedness of COMSAT aggregated  approximately $751 million. See  "Description
of  the Preferred Securities -- Tax Event or Investment Company Event Redemption
or Distribution" and "Description of the Junior Subordinated Debentures".

    In the event  of the liquidation  of COMSAT  Capital I, the  holders of  the
Preferred  Securities will be entitled to  receive for each Preferred Security a
liquidation preference of $25 plus accrued  and unpaid dividends thereon to  the
date of payment, subject to certain limitations, unless, in connection with such
liquidation,  Junior Subordinated Debentures  are distributed to  the holders of
the Preferred  Securities.  See  "Description of  the  Preferred  Securities  --
Liquidation Distribution Upon Dissolution".

    The  Preferred Securities  will be  represented by  a global  certificate or
certificates registered in the name of  The Depository Trust Company ("DTC")  or
its  nominee. Beneficial interests in the Preferred Securities will be shown on,
and transfers thereof will be effected  only through, records maintained by  the
participants  in  DTC.  Except  as  described  herein,  Preferred  Securities in
certificated form will not be issued  in exchange for the global certificate  or
certificates.  See "Description  of the Preferred  Securities -- Book-Entry-Only
Issuance -- The Depository Trust Company".

    Application will be made  to list the Preferred  Securities on the New  York
Stock Exchange.

                                       2
<PAGE>
                             AVAILABLE INFORMATION

    COMSAT  is  subject  to  the informational  requirements  of  the Securities
Exchange Act  of 1934,  as  amended (the  "Exchange  Act"), and,  in  accordance
therewith,  files  reports,  proxy  statements and  other  information  with the
Securities and  Exchange Commission  (the  "Commission"). These  reports,  proxy
statements  and  other information  can be  inspected and  copied at  the public
reference facilities maintained  by the  Commission at 450  Fifth Street,  N.W.,
Room 1024, Washington, D.C. 20549, as well as at the following Regional Offices:
7  World Trade Center,  New York, New  York 10048; and  500 West Madison Street,
Chicago, Illinois 60661. Copies of such material can be obtained from the Public
Reference Section of the Commission at 450 Fifth Street at prescribed rates  and
can be inspected at the New York, Chicago and Pacific Stock Exchanges.

    This  Prospectus  does not  contain  all the  information  set forth  in the
Registration Statement on Form  S-3 (together with  all amendments and  exhibits
thereto, the "Registration Statement") filed by COMSAT Capital I and COMSAT with
the  Commission under  the Securities Act  of 1933, as  amended (the "Securities
Act"). Reference is made to  the Registration Statement for further  information
with  respect to  COMSAT, COMSAT  Capital I  and the  securities offered hereby.
Statements  contained  or  incorporated  by  reference  herein  concerning   the
provisions  of documents are  necessarily summaries of  such documents, and each
statement is  qualified  in  its  entirety  by  reference  to  the  Registration
Statement.

    No  separate financial  statements of  COMSAT Capital  I have  been included
herein. COMSAT  and  COMSAT  Capital  I do  not  consider  that  such  financial
statements  would be material to holders  of Preferred Securities because COMSAT
Capital I is a  newly formed special purpose  entity, has no operating  history,
has  no independent operations  and is not  engaged in, and  does not propose to
engage in, any activity  other than as  set forth below. COMSAT  Capital I is  a
limited  partnership formed under the  laws of the State  of Delaware. COMSAT is
the sole  general partner  in  COMSAT Capital  I and,  as  of the  date  hereof,
directly  or indirectly beneficially owns all  of COMSAT Capital I's partnership
interests. See "COMSAT Capital I".
                                 --------------

                INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

    COMSAT's Annual Report on Form 10-K  for the fiscal year ended December  31,
1994, its Quarterly Report on Form 10-Q for the period ended March 31, 1995, and
its  Current  Report on  Form  8-K filed  on  May 30,  1995,  as filed  with the
Commission pursuant to the Exchange  Act, are incorporated herein by  reference.
All  documents filed by COMSAT pursuant to Sections 13(a), 13(c), 14 or 15(d) of
the Exchange Act  subsequent to the  date of  this Prospectus and  prior to  the
termination  of the offering of the securities offered hereby shall be deemed to
be incorporated by reference into this Prospectus  and to be a part hereof  from
the  date  of filing  such documents.  Any  statement contained  herein or  in a
document all or a portion of which is incorporated or deemed to be  incorporated
by reference herein shall be deemed to be modified or superseded for purposes of
this  Prospectus to the extent that a statement contained herein or in any other
subsequently filed document  which also is  or is deemed  to be incorporated  by
reference  herein modifies or  supersedes such statement.  Any such statement so
modified or superseded shall not be deemed, except as so modified or superseded,
to constitute a part of this Prospectus.

    COMSAT hereby undertakes to provide without charge to each person to whom  a
copy  of this Prospectus has  been delivered, on the  written or oral request of
any such person, including  any beneficial owner,  a copy of any  or all of  the
documents  referred to  above which  have been  or may  be incorporated  in this
Prospectus by  reference, other  than  exhibits to  such documents  unless  such
exhibits  are specifically incorporated  by reference into  the information that
the Prospectus  incorporates. Requests  for such  copies should  be directed  to
Nancy  E.  Weber, Assistant  Secretary  of COMSAT,  at  6560 Rock  Spring Drive,
Bethesda, MD 20817. Ms. Weber's telephone number is (301) 214-3643.

    IN CONNECTION WITH THIS OFFERING, THE UNDERWRITERS MAY OVER-ALLOT OR  EFFECT
TRANSACTIONS  WHICH STABILIZE  OR MAINTAIN  THE MARKET  PRICE OF  THE SECURITIES
OFFERED HEREBY AT A LEVEL ABOVE THAT  WHICH MIGHT OTHERWISE PREVAIL IN THE  OPEN
MARKET. SUCH TRANSACTIONS MAY BE EFFECTED ON THE NEW YORK STOCK EXCHANGE, IN THE
OVER-THE-COUNTER  MARKET OR  OTHERWISE. SUCH  STABILIZING, IF  COMMENCED, MAY BE
DISCONTINUED AT ANY TIME.

                                       3
<PAGE>
                                COMSAT CAPITAL I

    COMSAT  Capital  I  is a  limited  partnership  which was  formed  under the
Delaware Revised  Uniform Limited  Partnership Act  (the "Partnership  Act")  by
filing a certificate of limited partnership with the Delaware Secretary of State
on May 22, 1995. The initial partners in COMSAT Capital I are COMSAT, as general
partner,  and  COMSAT  SPV, Inc.,  a  Delaware  corporation and  a  wholly owned
subsidiary of COMSAT ("COMSAT  SPV"), as limited partner.  Upon the issuance  of
the  Preferred Securities, which securities  represent limited partner interests
in COMSAT Capital I, COMSAT SPV will remain as a limited partner, but will  have
no  interest in the profits and dividends or  in the assets of COMSAT Capital I.
The General Partner will contribute capital in an amount equal to at least 3% of
the total  capital contributions  to COMSAT  Capital I.  COMSAT and  COMSAT  SPV
entered  into a  limited partnership  agreement dated as  of May  22, 1995. Such
limited partnership agreement will be amended  and restated in its entirety  (as
so  amended and restated, the  "Limited Partnership Agreement") substantially in
the form  filed  as an  exhibit  to the  Registration  Statement of  which  this
Prospectus forms a part.

    COMSAT  Capital I is managed by the  General Partner and exists for the sole
purpose of issuing the Preferred  Securities and investing the proceeds  thereof
in  the  Junior Subordinated  Debentures.  The payment  by  COMSAT Capital  I of
dividends due on the Preferred Securities is solely dependent on its receipt  of
interest  payments from COMSAT on the Junior Subordinated Debentures. The rights
of the holders of the Preferred Securities, including economic rights, rights to
information and  voting  rights,  are  set  forth  in  the  Limited  Partnership
Agreement   and  the  Partnership   Act.  See  "Description   of  the  Preferred
Securities". COMSAT  Capital I  has a  term of  approximately 99  years,  unless
earlier dissolved. COMSAT Capital I's registered office in the State of Delaware
is  c/o The  Corporation Trust  Company, Corporation  Trust Center,  1209 Orange
Street,  Wilmington,  New  Castle  County,  Delaware  19801,  telephone:   (302)
658-7581.  All of COMSAT Capital  I's business and affairs  will be conducted by
COMSAT, as the sole general partner.  The principal place of business of  COMSAT
Capital I is c/o COMSAT Corporation, 6560 Rock Spring Drive, Bethesda, MD 20817,
telephone number (301) 214-3000.

                               COMSAT CORPORATION

GENERAL

    COMSAT is a global provider of communications and entertainment services and
products   primarily   operating  in   four  business   segments:  International
Communications, Mobile Communications, Entertainment and Technology Services.

    International  Communications  consists  of  COMSAT  World  Systems,   which
provides  satellite communications  services using  the satellite  system of the
International Telecommunications Satellite Organization ("INTELSAT"), and COMSAT
International  Ventures,  which  operates  and  invests  in   telecommunications
ventures  internationally.  Mobile  Communications  consists  of  COMSAT  Mobile
Communications, which  provides  satellite  communications  services  using  the
satellite   system   of   the   International   Mobile   Satellite  Organization
("Inmarsat").  Entertainment  consists  of  COMSAT  Entertainment  Group,  Inc.,
comprising  COMSAT  Video  Enterprises,  Inc.  and  COMSAT's  majority ownership
interest in On Command Video  Corporation, which provide entertainment  services
to  the hospitality  industry throughout  the United  States and  domestic video
distribution services to a television  network; the Denver Nuggets, a  franchise
of  the  National Basketball  Association;  and Beacon  Communications  Corp., a
producer of  theatrical films  and television  programming. Technology  Services
consists  of  COMSAT  RSI,  Inc., which  designs,  manufactures,  and integrates
satellite earth  stations,  advanced  antennas and  other  turnkey  systems  for
telecommunications,  radar, air traffic control  and military uses, and provides
turnkey  voice,  video  and  data  communications  networks  and  products,  and
communication  and  information  services  worldwide,  and  COMSAT Laboratories,
COMSAT's center for applied research and technology development.

    For the  year  ended December  31,  1994, the  International  Communications
segment  had revenues of $271  million and operating income  of $89 million; the
Mobile Communications segment had revenues

                                       4
<PAGE>
of $194 million and operating income  of $48 million; the Entertainment  segment
had  revenues  of $157  million and  operating  income of  $11 million;  and the
Technology Services segment had revenues of $219 million and operating income of
$15 million.

    COMSAT  was  incorporated  in  1963  under  District  of  Columbia  law,  as
authorized  by the Communications  Satellite Act of  1962 (the "Satellite Act").
Effective June 1, 1993, COMSAT  changed its corporate name from  "Communications
Satellite  Corporation"  to "COMSAT  Corporation". COMSAT  is  not an  agency or
establishment of the U.S. Government. The U.S. Government has not invested funds
in COMSAT, guaranteed  funds invested  in COMSAT  or guaranteed  the payment  of
dividends by COMSAT.

    Although COMSAT is a non-governmental publicly held corporation whose common
stock  is  traded on  the New  York  Stock Exchange,  the Satellite  Act governs
certain aspects  of COMSAT's  structure,  ownership and  operations,  including:
three  of COMSAT's  15 directors  are appointed by  the President  of the United
States with  the  advice and  consent  of  the United  States  Senate;  COMSAT's
issuances  of capital stock  and borrowings of  money must be  authorized by the
Federal Communications  Commission (the  "FCC"); there  are limitations  on  the
classes  of persons that  may hold shares  of COMSAT's capital  stock and on the
number of shares a person or class of persons may hold; and, on matters that may
affect the national interest and foreign  policy of the United States,  COMSAT's
representatives  to  INTELSAT and  Inmarsat receive  instructions from  the U.S.
Government. Congress has  reserved the  right to  amend the  Satellite Act,  and
amendments, if any, could materially affect COMSAT.

    Under    the   Satellite   Act,   the   International   Maritime   Satellite
Telecommunications Act of 1978 and the  Communications Act of 1934, as  amended,
COMSAT  is subject  to regulation by  the FCC  with respect to  its COMSAT World
Systems and  COMSAT Mobile  Communications services  and the  rates charged  for
those  services. FCC decisions and policies have had and will continue to have a
significant impact on COMSAT.

    The principal  place  of business  of  COMSAT  is 6560  Rock  Spring  Drive,
Bethesda, MD 20817, telephone number (301) 214-3000.

RECENT DEVELOPMENTS

    On  May 25, 1995, COMSAT Entertainment Group, Inc. announced an agreement to
buy  the  Qubec   Nordiques  National  Hockey   League  ("NHL")  franchise   for
approximately $75 million. COMSAT plans to transfer the team to Denver, Colorado
in  time for the 1995-96 NHL season.  The transaction and transfer fees, if any,
are subject to approval by the NHL Board of Governors.

                                       5
<PAGE>
                                  RISK FACTORS

    PROSPECTIVE PURCHASERS OF PREFERRED  SECURITIES SHOULD CAREFULLY REVIEW  THE
INFORMATION  CONTAINED  ELSEWHERE  IN THIS  PROSPECTUS  AND  SHOULD PARTICULARLY
CONSIDER THE FOLLOWING MATTERS:

SUBORDINATION OF GUARANTEE AND JUNIOR SUBORDINATED DEBENTURES

    COMSAT's obligations under the Guarantee are subordinate and junior in right
of payment  to  all  other  liabilities  of  COMSAT  except  for  certain  other
guarantees  that may be executed by COMSAT in respect of preferred securities of
certain affiliates  of  COMSAT.  The  obligations of  COMSAT  under  the  Junior
Subordinated  Debentures described under "Description of the Junior Subordinated
Debentures"  are  subordinate  and  junior   in  right  of  payment  to   Senior
Indebtedness  of  COMSAT.  At  March 31,  1995,  Senior  Indebtedness  of COMSAT
aggregated approximately  $751 million.  There  are no  terms in  the  Preferred
Securities,  the  Junior Subordinated  Debentures  or the  Guarantee  that limit
COMSAT's ability to incur  additional indebtedness, including indebtedness  that
ranks  senior  to  the Junior  Subordinated  Debentures and  the  Guarantee. See
"Description of the Guarantee  -- Status of the  Guarantee" and "Description  of
the Junior Subordinated Debentures -- Subordination".

OPTION TO EXTEND INTEREST PAYMENT PERIOD

    COMSAT  has the  right under  the Indenture  to extend  the interest payment
period from time to time on the  Junior Subordinated Debentures to a period  not
exceeding 60 consecutive months, and, as a consequence, monthly dividends on the
Preferred  Securities would be deferred by  COMSAT Capital I (but would continue
to accrue  with interest  thereon)  during any  such extended  interest  payment
period. In the event that COMSAT exercises this right, COMSAT may not declare or
pay  dividends on,  or redeem,  purchase or acquire,  any of  its capital stock.
Prior to the termination of any such extension period, COMSAT may further extend
the interest payment period, provided  that such extension period together  with
all  such previous and further extensions  thereof may not exceed 60 consecutive
months. Upon the termination of any  extension period COMSAT is required to  pay
all  amounts then due and, upon such  payment, COMSAT may select a new extension
period, subject  to the  above requirements.  In no  event shall  any  extension
period  extend beyond the maturity of the Junior Subordinated Debentures. COMSAT
Capital I and  COMSAT believe  that the  extension of  a payment  period on  the
Junior  Subordinated Debentures is  unlikely. See "Description  of the Preferred
Securities -- Dividends" and "Description of the Junior Subordinated  Debentures
- - -- Option to Extend Interest Payment Period".

    Should  an extended  interest payment  period occur,  COMSAT Capital  I will
continue to accrue income  for United States federal  income tax purposes  which
will  be  allocated, but  not  distributed, to  holders  of record  of Preferred
Securities. As  a result,  such a  holder will  include such  interest in  gross
income  for United States federal income tax  purposes in advance of the receipt
of cash, and will  not receive the  cash from COMSAT Capital  I related to  such
income if such a holder disposes of his or her Preferred Securities prior to the
record  date for payment of dividends.  See "United States Taxation -- Potential
Extension of Interest Payment Period".

TAX EVENT OR INVESTMENT COMPANY EVENT REDEMPTION OR DISTRIBUTION

    Upon the occurrence of a Tax Event (as defined herein) or Investment Company
Event (as defined herein), the General  Partner will elect to either (i)  redeem
the  Preferred Securities in whole  or (ii) dissolve COMSAT  Capital I and cause
Junior Subordinated Debentures to be distributed to the holders of the Preferred
Securities in connection with the liquidation  of COMSAT Capital I. In the  case
of  a  Tax Event,  the General  Partner may  also elect  to cause  the Preferred
Securities to remain outstanding and pay Additional Interest (as defined herein)
on the Junior Subordinated Debentures.  The Junior Subordinated Debentures  will
initially  be issued at face value as  a Global Security (as defined herein) and
will be limited in aggregate principal amount to approximately $   million, such
amount being  the sum  of the  aggregate stated  liquidation preference  of  the
Preferred  Securities and the  General Partnership Payment  (as defined herein).
See "Description of the Preferred Securities -- Tax Event or Investment  Company
Event  Redemption or Distribution"  and "Description of  the Junior Subordinated
Debentures -- General".

                                       6
<PAGE>
    Under current United States  federal income tax law,  a distribution of  the
Junior  Subordinated Debentures would not  be a taxable event  to holders of the
Preferred Securities. Under a change in law, a change in legal interpretation or
the other circumstances giving rise to a Tax Event or Investment Company  Event,
however,  the dissolution could be  a taxable event to  holders of the Preferred
Securities. In the judgment of special tax counsel to COMSAT and COMSAT  Capital
I, the series of events which would result in the recognition of taxable gain or
loss  by holders  of the  Preferred Securities,  by reason  of a  dissolution of
COMSAT Capital I  in response to  a Tax  Event or Investment  Company Event,  is
unlikely  to  occur. There  can be  no  assurance in  this regard,  however. See
"United States  Taxation  --  Receipt of  Junior  Subordinated  Debentures  Upon
Liquidation or Merger of COMSAT Capital I".

REPLACEMENT OF COMSAT CAPITAL I WITH A TRUST

    Subject  to certain  conditions, COMSAT Capital  I has the  right to replace
COMSAT Capital  I  with a  trust  as the  issuing  vehicle. In  the  event  such
replacement  is made, investors' rights in  the successor securities will remain
materially unchanged; however, investors will receive for tax reporting purposes
a Form 1099 instead of a Form K-1. It is expected that the Preferred  Securities
and any such successor securities will be listed as equity securities on the New
York Stock Exchange. Accordingly, the Preferred Securities are expected to trade
"flat";  thus, purchasers will not pay and  sellers will not receive any accrued
and unpaid interest  on the  Preferred Securities or  such successor  securities
that  is not included in the trading price. However, if the replacement is made,
for United  States  Federal income  tax  purposes, interest  on  the  applicable
successor securities will be included in income as it accrues (regardless of the
method  of accounting otherwise used), rather than when it is allocated or paid.
See "Description  of  the  Preferred  Securities  --  Merger,  Consolidation  or
Amalgamation  of  COMSAT  Capital I",  "United  States Taxation  --  Income from
Preferred Securities"  and "United  States Taxation  -- Potential  Extension  of
Interest Payment Period".

                                       7
<PAGE>
                    SUMMARY FINANCIAL INFORMATION OF COMSAT

    The  selected data presented below under the caption "Income Statement Data"
for each of  the years  in the  three-year period  ended December  31, 1994  and
"Balance Sheet Data" as of December 31, 1994 and 1993 have been derived from the
consolidated financial statements of COMSAT, which have been audited by Deloitte
&  Touche LLP, independent auditors. The selected consolidated "Income Statement
Data" for each of the years ended December 31, 1991 and 1990 and "Balance  Sheet
Data"  as of December 31, 1992, 1991 and 1990 are derived from audited financial
statements of  COMSAT not  included  or incorporated  by reference  herein.  The
selected data presented below as of and for each of the quarters ended March 31,
1995  and 1994 have  been derived from the  consolidated financial statements of
COMSAT, which  have  not  been  audited,  but in  the  opinion  of  COMSAT  such
information   includes  all  adjustments,  consisting  of  normal  or  recurring
adjustments,  necessary  for  a  fair  presentation  of  such  information.  The
consolidated financial statements as of December 31, 1994 and 1993, and for each
of  the  years  in  the  three-year period  ended  December  31,  1994,  and the
independent auditors' report  thereon (which includes  an explanatory  paragraph
referring  to the change in its method  of accounting for income taxes), and the
condensed consolidated financial statements as of  and for each of the  quarters
ended  March  31, 1995  and  1994 and  Management's  Discussion and  Analysis of
Financial Condition and Results  of Operations ("MD&A")  for such periods,  have
been  incorporated by reference herein.  See "Incorporation of Certain Documents
by Reference".  The financial  information  presented below  should be  read  in
conjunction  with such consolidated  financial statements and  the notes thereto
and such MD&A.

<TABLE>
<CAPTION>
                                 QUARTER ENDED MARCH
                                   31, (UNAUDITED)                       YEAR ENDED DECEMBER 31,
                                ----------------------  ----------------------------------------------------------
                                   1995        1994        1994        1993        1992        1991        1990
                                ----------  ----------  ----------  ----------  ----------  ----------  ----------
                                                   (IN THOUSANDS, EXCEPT PER SHARE INFORMATION)
<S>                             <C>         <C>         <C>         <C>         <C>         <C>         <C>
INCOME STATEMENT DATA:
Revenues......................  $  207,883  $  200,495  $  826,899  $  754,285  $  688,093  $  651,211  $  563,462
Operating expenses............     178,126     163,621     676,648     602,705     583,111     508,499     563,980
Operating income (loss).......      29,757      36,874     150,251     151,580     104,982     142,712        (518)
Income (loss) before
 cumulative effect of changes
 in accounting principles.....      14,573      20,181      77,642      82,469      53,292      81,014      (9,045)
Cumulative effect of changes
 in accounting principles.....      --          --          --           1,925      --         (26,607)     --
Net income (loss).............      14,573      20,181      77,642      84,394      53,292      54,407      (9,045)
Dividends paid................       9,178       7,446      33,547      30,410      27,837      25,867      25,219
Primary earnings (loss) per
 share........................        0.31        0.43        1.64        1.79        1.16        1.22       (0.21)
Dividends paid per share......       0.195       0.185        0.76        0.74        0.70        0.67        0.66

BALANCE SHEET DATA:
Total assets..................   2,017,219   1,975,992   1,975,992   1,773,513   1,654,985   1,469,516   1,300,683
Long-term debt................     569,440     515,542     515,542     410,550     496,804     391,308     383,695
Stockholders' equity..........     837,713     826,916     826,916     763,440     702,292     657,783     619,150
</TABLE>

                                       8
<PAGE>
                  RATIO OF EARNINGS TO FIXED CHARGES OF COMSAT

<TABLE>
<CAPTION>
                                                     QUARTER
                                                      ENDED
                                                    MARCH 31,       YEAR ENDED DECEMBER 31,
                                                    ----------  -------------------------------
                                                    1995  1994  1994  1993  1992  1991  1990(2)
                                                    ----  ----  ----  ----  ----  ----  -------
<S>                                                 <C>   <C>   <C>   <C>   <C>   <C>   <C>
Ratio of Earnings to Fixed Charges: (1)...........  2.4   3.4   3.4   3.7   2.6   3.1       --
<FN>
- - --------------
(1)  For purposes of calculating this  ratio, fixed charges consist of  interest
     expense   including  capitalized  interest,  the  interest  expense  of  an
     unconsolidated majority-owned investment  in 1990,  1991 and  1992, and  an
     estimate  of the  interest factor  of rental  expense. Earnings  consist of
     pretax income (loss) from continuing  operations before fixed charges,  the
     losses   and  undistributed   earnings  of   equity  investments   and  the
     amortization of capitalized interest. During the periods presented,  COMSAT
     did  not have any  preferred stock issued  or outstanding. Accordingly, the
     ratio of earnings to combined  fixed charges and preferred stock  dividends
     is not presented.
(2)  1990  earnings were  inadequate to cover  fixed charges, as  such terms are
     defined in Item  503(d) of Regulation  S-K, with a  coverage deficiency  of
     $23,726,000.  However,  1990  earnings include  a  $97,576,000 nonrecurring
     charge related to  the restructuring  of the  video entertainment  business
     unit.
</TABLE>

                                USE OF PROCEEDS

    The  proceeds from the sale of the  Preferred Securities will be invested in
the Junior Subordinated  Debentures issued pursuant  to the Indenture  described
herein.  In addition,  concurrently with the  sale of  the Preferred Securities,
COMSAT Capital  II,  L.P. may  sell  its      %  Share-linked  Income  Preferred
Securities  (the "Convertible  Preferred Securities"),  the proceeds  from which
would be invested  in COMSAT's    % Convertible  Junior Subordinated  Deferrable
Interest  Debentures.  The aggregate  proceeds from  the  sale of  the Preferred
Securities and  the  Convertible  Preferred  Securities  will  not  exceed  $200
million.  Ultimately, such proceeds will be used by COMSAT to reduce outstanding
commercial paper (at May  30, 1995, totaling approximately  $115 million, at  an
average  interest cost  of approximately  6%) and  approximately $75  million of
indebtedness that  COMSAT  may incur  to  fund  the acquisition  of  the  Quebec
Nordiques  NHL  franchise,  and  for  general  corporate  purposes.  See "COMSAT
Corporation -- Recent Developments".

                            CAPITALIZATION OF COMSAT

    The following table sets forth  the consolidated short-term obligations  and
capitalization  of COMSAT as of  March 31, 1995, and  as adjusted to reflect the
application of  the  estimated net  proceeds  from  the sale  of  the  Preferred
Securities  and the Convertible Preferred Securities (assuming the underwriters'
over-allotment option with  respect to the  Convertible Preferred Securities  is
not exercised). See "Use of Proceeds".

<TABLE>
<CAPTION>
                                                                                               MARCH 31, 1995
                                                                                           -----------------------
                                                                                            ACTUAL    AS ADJUSTED
                                                                                           ---------  ------------
                                                                                                (IN MILLIONS)
<S>                                                                                        <C>        <C>
Commercial paper and current maturities of long-term obligations.........................  $     149   $
                                                                                           ---------  ------------
                                                                                           ---------  ------------
Long-term debt...........................................................................  $     569   $
                                                                                           ---------  ------------
Company-obligated mandatorily redeemable preferred securities issued by subsidiary.......          0
                                                                                           ---------  ------------
Stockholders' equity:
  Common stock...........................................................................        315
  Preferred stock........................................................................          0
  Retained earnings......................................................................        538
  Treasury stock (at cost)...............................................................        (12)
  Other..................................................................................         (3)
                                                                                           ---------  ------------
    Total stockholders' equity...........................................................        838
                                                                                           ---------  ------------
    Total capitalization (excluding short-term obligations)..............................  $   1,407   $
                                                                                           ---------  ------------
                                                                                           ---------  ------------
</TABLE>

                                       9
<PAGE>
                    DESCRIPTION OF THE PREFERRED SECURITIES

    THE  FOLLOWING  SUMMARY  OF CERTAIN  MATERIAL  TERMS AND  PROVISIONS  OF THE
PREFERRED SECURITIES DOES  NOT PURPORT  TO BE COMPLETE  AND IS  SUBJECT TO,  AND
QUALIFIED  IN ITS ENTIRETY BY REFERENCE TO, THE LIMITED PARTNERSHIP AGREEMENT, A
COPY OF WHICH IS FILED AS AN EXHIBIT TO THE REGISTRATION STATEMENT OF WHICH THIS
PROSPECTUS IS A PART.  CAPITALIZED TERMS NOT OTHERWISE  DEFINED HEREIN HAVE  THE
MEANINGS ASSIGNED TO THEM IN THE LIMITED PARTNERSHIP AGREEMENT.

GENERAL

    All  of  the  partnership interests  in  COMSAT  Capital I,  other  than the
Preferred Securities offered hereby, are owned directly or indirectly by COMSAT.
The  Limited  Partnership  Agreement   authorizes  and  creates  the   Preferred
Securities,  which represent limited partner interests  in COMSAT Capital I. The
limited partner interests represented  by the Preferred  Securities will have  a
preference with respect to dividends and amounts payable on liquidation over the
General  Partner's  interest  in  COMSAT  Capital  I.  The  Limited  Partnership
Agreement does  not  permit  the  issuance  of  any  other  limited  partnership
interests  or preferred securities of COMSAT Capital I, or the incurrence of any
indebtedness by COMSAT Capital I.

DIVIDENDS

    The dividends payable on each Preferred Security will be fixed at a rate per
annum of       % of  the  stated liquidation  preference  of $25  per  Preferred
Security.  Dividends in arrears will bear interest thereon at the rate per annum
of    % thereof. The term "dividends" as used herein includes any such  interest
payable  unless otherwise stated. The amount of dividends payable for any period
will be computed on the basis of a 360-day year of twelve 30-day months.

    Dividends on the Preferred Securities  will be cumulative, will accrue  from
the date of initial issuance and will be payable monthly in arrears, on the last
day of each calendar month of each year, commencing             , 1995, when, as
and  if available  and determined  to be  so payable  by COMSAT,  as the General
Partner, except as  otherwise described below.  COMSAT has the  right under  the
Indenture  to extend the interest payment period from time to time on the Junior
Subordinated Debentures to a period not exceeding 60 consecutive months, and, as
a consequence, monthly dividends on  the Preferred Securities would be  deferred
by COMSAT Capital I (but would continue to accrue with interest) during any such
extended interest payment period. In the event that COMSAT exercises this right,
COMSAT  may not declare or pay dividends on, or redeem, purchase or acquire, any
of its capital  stock. Prior to  the termination of  any such extension  period,
COMSAT  may  further  extend the  interest  payment period,  provided  that such
extension period together with all such previous and further extensions  thereof
may  not exceed  60 consecutive  months. Upon  the termination  of any extension
period COMSAT is required to  pay all amounts then  due and, upon such  payment,
COMSAT  may select a new extension period, subject to the above requirements. In
no event shall  any extension period  extend beyond the  maturity of the  Junior
Subordinated  Debentures. See "Description of the Junior Subordinated Debentures
- - -- Interest" and "-- Option to Extend Interest Payment Period".

    Dividends on the Preferred Securities must  be declared monthly and paid  on
the  dates payable  to the extent  that COMSAT  Capital I has  (i) funds legally
available for the payment of such dividends and (ii) cash on hand sufficient  to
permit  such  payments.  It  is anticipated  that  COMSAT  Capital  I's earnings
available for distribution to  the holders of the  Preferred Securities will  be
limited  to payments  under the Junior  Subordinated Debentures  in which COMSAT
Capital I will invest the proceeds from  the issuance and sale of the  Preferred
Securities. See "Description of the Junior Subordinated Debentures". The payment
of  dividends, to the extent declared by COMSAT  Capital I out of moneys held by
COMSAT Capital I and legally available therefor, is guaranteed by COMSAT as  set
forth under "Description of the Guarantee".

    Dividends on the Preferred Securities will be payable to the holders thereof
as  they appear  on the books  and records of  COMSAT Capital I  on the relevant
record dates, which will  be one Business  Day (as defined  below) prior to  the
relevant  payment  dates. Subject  to any  applicable  laws and  regulations and

                                       10
<PAGE>
the provisions of the Limited Partnership  Agreement, each such payment will  be
made  as  described  under  "Book-Entry-Only Issuance  --  The  Depository Trust
Company" below. In  the event  the Preferred  Securities shall  not continue  to
remain  in book-entry-only  form, the  General Partner  shall have  the right to
select relevant record dates which shall be more than one Business Day prior  to
the  relevant payment dates. In  the event that any  date on which dividends are
payable on the Preferred Securities is not  a Business Day, then payment of  the
dividend payable on such date will be made on the next succeeding day which is a
Business  Day (and without any interest or  other payment in respect of any such
delay) except that,  if such  Business Day is  in the  next succeeding  calendar
year,  such payment shall be made on  the immediately preceding Business Day, in
each case with the same  force and effect as if  made on such date. A  "Business
Day"  shall mean any day  other than a day on  which banking institutions in The
City of New York are authorized or required by law to close.

OPTIONAL REDEMPTION

    The Preferred Securities are redeemable at  the option of COMSAT Capital  I,
in whole or in part, from time to time, on or after             , 2000, upon not
less  than 30  nor more than  60 days' notice,  at the Redemption  Price. In the
event that fewer  than all  the outstanding Preferred  Securities are  to be  so
redeemed,  the Preferred Securities to be redeemed will be selected as described
under "Book-Entry-Only Issuance  -- The  Depository Trust Company"  below. If  a
partial  redemption would result  in the delisting  of the Preferred Securities,
COMSAT Capital I may only redeem the Preferred Securities in whole.

TAX EVENT OR INVESTMENT COMPANY EVENT REDEMPTION OR DISTRIBUTION

    If a Tax  Event shall  occur and be  continuing, the  General Partner  shall
elect  to (i) redeem the  Preferred Securities in whole  (and not in part), upon
not less than 30 nor more than 60 days' notice at the Redemption Price within 90
days following the occurrence of such Tax Event; provided, that, if at the  time
there  is available to the General  Partner the opportunity to eliminate, within
such 90-day period,  the Tax Event  by taking some  ministerial action, such  as
filing  a form or making an election,  or pursuing some other similar reasonable
measure, which has no adverse effect on COMSAT Capital I or COMSAT, the  General
Partner  will pursue  such measure in  lieu of redemption,  (ii) dissolve COMSAT
Capital I and  cause Junior  Subordinated Debentures  to be  distributed to  the
holders of the Preferred Securities in liquidation of COMSAT Capital I, or (iii)
cause the Preferred Securities to remain outstanding and pay Additional Interest
on   the  Junior  Subordinated  Debentures.   See  "Description  of  the  Junior
Subordinated Debentures -- Additional Interest".

    "Tax Event" means that the General Partner shall have obtained an opinion of
nationally recognized independent tax counsel experienced in such matters to the
effect that, as  a result  of (a)  any amendment  to, or  change (including  any
announced  prospective change) in,  the laws (or  any regulations thereunder) of
the United States or  any political subdivision or  taxing authority thereof  or
therein,  (b) any amendment to or change  in an interpretation or application of
such laws or regulations by any legislative body, court, governmental agency  or
regulatory  authority  (including  the  enactment  of  any  legislation  and the
publication of any judicial decision or regulatory determination on or after the
date of  this  Prospectus)  or  (c) any  interpretation  or  pronouncement  that
provides  for a position with  respect to such laws  or regulations that differs
from the  generally accepted  position on  the date  of this  Prospectus,  which
amendment  or change  is effective or  which interpretation  or pronouncement is
announced on  or after  the  date of  this Prospectus,  there  is more  than  an
insubstantial  risk that (i) COMSAT  Capital I is subject  to federal income tax
with respect to interest  received on the  Junior Subordinated Debentures,  (ii)
interest  payable to COMSAT Capital I on the Junior Subordinated Debentures will
not be deductible for federal income tax  purposes or (iii) COMSAT Capital I  is
subject  to  more than  a  DE MINIMIS  amount of  other  taxes, duties  or other
governmental charges.

    If an Investment Company  Event shall occur and  be continuing, the  General
Partner  shall elect to either (i) redeem the Preferred Securities in whole (and
not in  part), upon  not less  than 30  nor more  than 60  days' notice  at  the
Redemption  Price within  90 days  following the  occurrence of  such Investment
Company Event; provided, that, if at the time there is available to the  General
Partner the opportunity to

                                       11
<PAGE>
eliminate, within such 90-day period, the Investment Company Act Event by taking
some  ministerial  action, such  as  filing a  form  or making  an  election, or
pursuing some other similar reasonable measure,  which has no adverse effect  on
COMSAT Capital I or COMSAT, the General Partner will pursue such measure in lieu
of  redemption,  or  (ii)  dissolve  COMSAT  Capital  I  and  cause  the  Junior
Subordinated Debentures  to  be distributed  to  the holders  of  the  Preferred
Securities  in liquidation  of COMSAT  Capital I,  within 90  days following the
occurrence of such Investment Company Event.

    "Investment Company  Event" means  the  occurrence of  a  change in  law  or
regulation  or  a written  change  in interpretation  or  application of  law or
regulation by any  legislative body,  court, governmental  agency or  regulatory
authority (a "Change in 1940 Act Law") to the effect that COMSAT Capital I is or
will  be considered an  "investment company" which is  required to be registered
under the Investment  Company Act of  1940, as amended  (the "1940 Act"),  which
Change  in  1940  Act  Law  becomes  effective on  or  after  the  date  of this
Prospectus; provided, that no Investment Company  Event shall be deemed to  have
occurred  if  the  General  Partner  obtains  a  written  opinion  of nationally
recognized independent counsel experienced in practice under the 1940 Act to the
effect that  the  General  Partner  has successfully  issued  an  additional  or
supplemental  irrevocable and unconditional guarantee  (x) of accrued and unpaid
dividends (whether or not determined to be paid out of moneys legally  available
therefor)  on  the  Preferred Securities  and  (y)  of the  full  amount  of the
Liquidation Distribution (as defined below)  on the Preferred Securities upon  a
liquidation  of COMSAT Capital I  (regardless of the amount  of assets of COMSAT
Capital I otherwise  available for  distribution in such  liquidation) to  avoid
such  Change  in  1940  Act  Law  so  that  in  the  opinion  of  such  counsel,
notwithstanding such Change in 1940 Act Law, COMSAT Capital I is not required to
be registered as an "investment company" within the meaning of the 1940 Act.

    After the date fixed for any distribution of Junior Subordinated  Debentures
upon  dissolution  of COMSAT  Capital I,  (i) the  Preferred Securities  will no
longer be  deemed to  be outstanding,  (ii) The  Depository Trust  Company  (the
"Depository"  or "DTC") or  its nominee, as  the record holder  of the Preferred
Securities,  will  receive  a  registered  global  certificate  or  certificates
representing  the  Junior  Subordinated  Debentures to  be  delivered  upon such
distribution and (iii)  any certificates representing  Preferred Securities  not
held  by DTC  or its  nominee will  be deemed  to represent  Junior Subordinated
Debentures having  a principal  amount  equal to  the  aggregate of  the  stated
liquidation  preference of  such Preferred  Securities, with  accrued and unpaid
interest equal to the amount of  accrued and unpaid dividends on such  Preferred
Securities,  until such  certificates are presented  to COMSAT or  its agent for
transfer or reissuance.

MANDATORY REDEMPTION

    Upon the repayment of the Junior Subordinated Debentures at maturity or upon
any acceleration,  earlier  redemption  or otherwise,  the  proceeds  from  such
repayment will be applied to redeem the Preferred Securities, in whole, upon not
less than 30 nor more than 60 days' notice, at the Redemption Price.

REDEMPTION PROCEDURES

    COMSAT  Capital I  may not redeem  fewer than all  the outstanding Preferred
Securities unless  all  accrued and  unpaid  dividends  have been  paid  on  all
Preferred Securities for all monthly dividend periods terminating on or prior to
the date of redemption.

    If  COMSAT Capital I  gives a notice  of redemption in  respect of Preferred
Securities (which notice  will be irrevocable),  then, by 12:00  noon, New  York
time, on the redemption date, COMSAT Capital I will irrevocably deposit with DTC
funds  sufficient  to pay  the  applicable Redemption  Price  and will  give DTC
irrevocable instructions  and  authority to  pay  the Redemption  Price  to  the
holders  of  the  Preferred  Securities. See  "Book-Entry-Only  Issuance  -- The
Depository Trust Company".  If notice of  redemption shall have  been given  and
funds  are deposited as required, then upon the date of such deposit, all rights
of holders of  such Preferred Securities  so called for  redemption will  cease,
except  the right  of the  holders of such  Preferred Securities  to receive the
Redemption Price, but without  interest on such Redemption  Price. In the  event
that  any date fixed  for redemption of  Preferred Securities is  not a Business
Day, then payment of the Redemption Price  payable on such date will be made  on
the next succeeding day which

                                       12
<PAGE>
is  a Business Day (and without any interest  or other payment in respect of any
such delay), except that, if such Business Day falls in the next calendar  year,
such  payment will  be made  on the immediately  preceding Business  Day. In the
event that payment of the Redemption Price in respect of Preferred Securities is
improperly withheld or refused  and not paid  either by COMSAT  Capital I or  by
COMSAT pursuant to the Guarantee described under "Description of the Guarantee",
dividends  on  such Preferred  Securities will  continue to  accrue at  the then
applicable rate, from the  original redemption date to  the date of payment,  in
which  case  the actual  payment  date will  be  considered the  date  fixed for
redemption for purposes of calculating the Redemption Price.

    Subject to the foregoing and applicable law (including, without  limitation,
United  States federal securities  laws), COMSAT or its  subsidiaries may at any
time and from time to time purchase outstanding Preferred Securities by  tender,
in the open market or by private agreement.

LIQUIDATION DISTRIBUTION UPON DISSOLUTION

    In  the event  of any  voluntary or  involuntary dissolution,  winding-up or
termination of COMSAT Capital I, the holders of the Preferred Securities at  the
time will be entitled to receive out of the assets of COMSAT Capital I available
for  distribution to partners after satisfaction  of liabilities of creditors as
required by the Partnership  Act, before any distribution  of assets is made  to
the  General Partner, an  amount equal to,  in the case  of holders of Preferred
Securities, the  aggregate  of the  stated  liquidation preference  of  $25  per
Preferred  Security  and accrued  and unpaid  dividends thereon  to the  date of
payment (the  "Liquidation  Distribution"),  unless,  in  connection  with  such
dissolution,  winding-up or  termination, Junior  Subordinated Debentures  in an
aggregate principal  amount  equal to  the  Liquidation Distribution  have  been
distributed on a pro rata basis to the holders of the Preferred Securities.

    Pursuant  to the  Limited Partnership Agreement,  COMSAT Capital  I shall be
dissolved and its  affairs shall  be wound  up: (i)  on December  31, 2094,  the
expiration  of the  term of COMSAT  Capital I,  (ii) upon the  bankruptcy of the
General Partner, (iii) upon the assignment by the General Partner of its  entire
interest in COMSAT Capital I when the assignee is not admitted to COMSAT Capital
I  as  a general  partner of  COMSAT Capital  I in  accordance with  the Limited
Partnership Agreement, or  the filing  of a  certificate of  dissolution or  its
equivalent with respect to the General Partner, or the revocation of the General
Partner's  charter and the expiration of 90 days after the date of notice to the
General Partner of  revocation without a  reinstatement of its  charter, or  any
other  event occurs which  causes the General  Partner to cease  to be a general
partner of COMSAT Capital  I under the Partnership  Act, unless the business  of
COMSAT  Capital I is continued  in accordance with the  Partnership Act, (iv) in
accordance with the provisions of the  Preferred Securities, (v) upon the  entry
of  a decree of a  judicial dissolution or (vi) upon  the written consent of all
partners of COMSAT Capital I.

MERGER, CONSOLIDATION OR AMALGAMATION OF COMSAT CAPITAL I

    COMSAT Capital I may not consolidate, amalgamate, merge with or into, or  be
replaced   by,  or  convey,   transfer  or  lease   its  properties  and  assets
substantially as  an  entirety to  any  corporation  or other  body,  except  as
described below. COMSAT Capital I may, without the consent of the holders of the
Preferred  Securities,  consolidate,  amalgamate,  merge  with  or  into,  or be
replaced by,  a limited  partnership, a  limited liability  company or  a  trust
organized as such under the laws of any state of the United States of America or
of the District of Columbia; provided, that (i) such successor entity either (x)
expressly assumes all of the obligations of COMSAT Capital I under the Preferred
Securities  or  (y) substitutes  for the  Preferred Securities  other securities
having substantially the same terms as the Preferred Securities (the  "Successor
Securities")  so  long  as  the  Successor  Securities  rank,  with  respect  to
participation in the  profits and dividends  or in the  assets of the  successor
entity,  at  least as  high as  the  Preferred Securities  rank with  respect to
participation in the profits and dividends or in the assets of COMSAT Capital I,
(ii) COMSAT expressly acknowledges  such successor entity as  the holder of  the
Junior  Subordinated Debentures, (iii) the Preferred Securities or any Successor
Securities  are  listed,  or  any  Successor  Securities  will  be  listed  upon
notification   of  issuance,  on  any  national  securities  exchange  or  other
organization on  which  the Preferred  Securities  are then  listed,  (iv)  such
merger,  consolidation, amalgamation or replacement does not cause the Preferred
Securities (including any

                                       13
<PAGE>
Successor Securities) to be downgraded by any nationally recognized  statistical
rating organization, (v) such merger, consolidation, amalgamation or replacement
does  not adversely affect  the powers, preferences and  other special rights of
the holders of the Preferred Securities (including any Successor Securities)  in
any  material respect,  (vi) such successor  entity has  a purpose substantially
identical to that of COMSAT Capital I, (vii) COMSAT has provided a guarantee  to
the  holders of the  Successor Securities with respect  to such successor entity
having substantially the same terms as  the Guarantee, and (viii) prior to  such
merger,  consolidation,  amalgamation  or replacement,  COMSAT  has  received an
opinion of  nationally  recognized  independent  counsel  to  COMSAT  Capital  I
experienced  in such matters to  the effect that (x)  such successor entity will
not be treated as an association taxable as a corporation for federal income tax
purposes, (y) following such merger, consolidation, amalgamation or replacement,
neither COMSAT nor  such successor  entity will be  required to  register as  an
investment  company  under  the 1940  Act  and (z)  such  merger, consolidation,
amalgamation or replacement will not  adversely affect the limited liability  of
the  holders of  the Preferred Securities.  See "Risk Factors  -- Replacement of
COMSAT Capital I with a Trust".

VOTING RIGHTS

    Except as  provided  below  and  under  "Description  of  the  Guarantee  --
Amendments  and Assignment"  and as  otherwise required  by law  and the Limited
Partnership Agreement,  the holders  of the  Preferred Securities  will have  no
voting rights.

    If  (i) COMSAT  Capital I fails  to pay  dividends in full  on the Preferred
Securities for 18 consecutive monthly dividend periods; (ii) an Event of Default
(as  defined  in  the  Indenture)  occurs  and  is  continuing  on  the   Junior
Subordinated  Debentures; or (iii) COMSAT is in default on any of its payment or
other obligations under the  Guarantee (as described  under "Description of  the
Guarantee  -- Certain Covenants  of COMSAT"), then the  holders of the Preferred
Securities will be entitled by the majority vote of such holders to appoint  and
authorize  a special representative of COMSAT Capital I and the limited partners
(a "Special Representative") to enforce COMSAT Capital I's creditor rights under
the Junior Subordinated Debentures, to enforce the rights of the holders of  the
Preferred  Securities  under the  Guarantee  and to  enforce  the rights  of the
holders of  the  Preferred Securities  to  receive dividends  on  the  Preferred
Securities.  The  Special  Representative shall  not  be admitted  as  a general
partner in COMSAT Capital I  or otherwise be deemed to  be a general partner  in
COMSAT  Capital I  and shall  have no  liability for  the debts,  obligations or
liabilities of  COMSAT Capital  I. For  purposes of  determining whether  COMSAT
Capital  I  has failed  to  pay dividends  in  full for  18  consecutive monthly
dividend  periods,   dividends   shall  be   deemed   to  remain   in   arrears,
notwithstanding any payments in respect thereof, until full cumulative dividends
have  been or  contemporaneously are paid  with respect to  all monthly dividend
periods terminating on or prior to the  date of payment of such full  cumulative
dividends.  Not  later  than 30  days  after  such right  to  appoint  a Special
Representative arises,  the  General Partner  will  convene a  meeting  for  the
purpose  of appointing a Special Representative. If the General Partner fails to
convene  such  meeting  within  such  30-day  period,  the  holders  of  10%  in
liquidation  preference of the outstanding Preferred Securities will be entitled
to convene such  meeting. The  provisions of the  Limited Partnership  Agreement
relating to the convening and conduct of the meetings of the partners will apply
with  respect to any such meeting. Any Special Representative so appointed shall
cease to  be  a Special  Representative  of COMSAT  Capital  I and  the  limited
partners  if COMSAT Capital I  (or COMSAT pursuant to  the Guarantee) shall have
paid in full  all accrued and  unpaid dividends on  the Preferred Securities  or
such  default or breach, as the case may  be, shall have been cured, and COMSAT,
in its capacity as  the General Partner, shall  continue the business of  COMSAT
Capital  I  without dissolution.  Notwithstanding  the appointment  of  any such
Special Representative,  COMSAT  shall continue  as  General Partner  and  shall
retain  all  rights  under the  Indenture,  including  the right  to  extend the
interest payment  period  from  time  to  time to  a  period  not  exceeding  60
consecutive  months as  provided under  "Description of  the Junior Subordinated
Debentures -- Option to Extend Interest Payment Period".

    If any proposed amendment to the Limited Partnership Agreement provides for,
or the General Partner otherwise proposes to effect, (i) any action which  would
adversely  affect the  powers, preferences  or special  rights of  the Preferred
Securities,  whether   by  way   of  amendment   to  the   Limited   Partnership

                                       14
<PAGE>
Agreement  or  otherwise (including,  without  limitation, the  authorization or
issuance of any  limited partner interests  in COMSAT Capital  I other than  the
Preferred  Securities), or  (ii) the  dissolution, winding-up  or termination of
COMSAT Capital I, other than (x)  in connection with the distribution of  Junior
Subordinated  Debentures  upon  the occurrence  of  a  Special Event  or  (y) as
described under  "Merger, Consolidation  or Amalgamation  of COMSAT  Capital  I"
above,  then the holders of outstanding Preferred Securities will be entitled to
vote on such amendment or proposal of the General Partner (but not on any  other
amendment  or proposal), and  such amendment or proposal  shall not be effective
except with the approval of the holders of 66 2/3% in liquidation preference  of
such  outstanding Preferred  Securities having  a right  to vote  on the matter;
provided, however, that no such approval  shall be required if the  dissolution,
winding-up  or termination of COMSAT Capital I is proposed or initiated upon the
initiation of  proceedings or  after  proceedings have  been initiated  for  the
dissolution, winding-up, liquidation or termination of COMSAT.

    So  long as any Junior Subordinated Debentures are held by COMSAT Capital I,
the General  Partner  shall  not  (i)  direct the  time,  method  and  place  of
conducting  any proceeding for  any remedy available to  the Trustee (as defined
herein), or executing any trust or  power conferred on the Trustee with  respect
to  any series  of Junior Subordinated  Debentures, (ii) waive  any past default
which is waivable under Section 6.06 of the Indenture, (iii) exercise any  right
to  rescind or annul  a declaration that  the principal of  any series of Junior
Subordinated Debentures  shall  be  due  and payable  or  (iv)  consent  to  any
amendment,  modification  or termination  of the  Indenture, where  such consent
shall be required, without,  in each case, obtaining  the prior approval of  the
holders  of  at  least  66  2/3%  in  liquidation  preference  of  the Preferred
Securities; provided, however, that  where a consent  under the Indenture  would
require  the consent of each  holder affected thereby, no  such consent shall be
given by  the  General Partner  without  the prior  consent  of each  holder  of
Preferred Securities. The General Partner shall not revoke any action previously
authorized  or  approved by  a  vote of  the  Preferred Securities.  The General
Partner shall notify all  holders of the Preferred  Securities of any notice  of
default  received  from  the Trustee  with  respect to  the  Junior Subordinated
Debentures.

    Any required approval of holders of  Preferred Securities may be given at  a
separate  meeting of holders of Preferred  Securities convened for such purpose,
at a meeting of all of the partners  in COMSAT Capital I or pursuant to  written
consent. COMSAT Capital I will cause a notice of any meeting at which holders of
Preferred Securities are entitled to vote, or of any matter upon which action by
written  consent of such holders is to be  taken, to be mailed to each holder of
record of  Preferred  Securities. Each  such  notice will  include  a  statement
setting  forth (i) the date of such meeting  or the date by which such action is
to be taken, (ii) a description of any resolution proposed for adoption at  such
meeting  on which such holders are entitled to vote or of such matter upon which
written consent is sought and (iii) instructions for the delivery of proxies  or
consents.

    No  vote or consent of the holders  of Preferred Securities will be required
for COMSAT Capital  I to redeem  and cancel Preferred  Securities in  accordance
with the Limited Partnership Agreement.

    Notwithstanding that holders of Preferred Securities are entitled to vote or
consent  under any  of the circumstances  described above, any  of the Preferred
Securities that are  owned by COMSAT  or by any  entity owned more  than 50%  by
COMSAT,  or by any  entity controlled by COMSAT,  either directly or indirectly,
shall not be entitled to vote or consent and shall, for purposes of such vote or
consent, be treated as if they were not outstanding.

    Holders of the Preferred Securities will have no rights to remove or replace
the General Partner.

BOOK-ENTRY-ONLY ISSUANCE -- THE DEPOSITORY TRUST COMPANY

    DTC will  act as  securities depository  for the  Preferred Securities.  The
Preferred   Securities  will  be  issued  only  as  fully-registered  securities
registered  in  the  name   of  Cede  &  Co.   (DTC's  nominee).  One  or   more
fully-registered   global  Preferred  Security   certificates  will  be  issued,
representing in the aggregate the total number of Preferred Securities, and will
be deposited with, DTC.

                                       15
<PAGE>
    DTC  is a limited-purpose trust company organized under the New York Banking
Law, a "banking organization" within the meaning of the New York Banking Law,  a
member  of  the  Federal Reserve  System,  a "clearing  corporation"  within the
meaning of  the  New York  Uniform  Commercial  Code, and  a  "clearing  agency"
registered  pursuant to the provisions  of Section 17A of  the Exchange Act. DTC
holds securities that  its participants ("Participants")  deposit with DTC.  DTC
also  facilitates the settlement among  Participants of securities transactions,
such as  transfers  and  pledges, in  deposited  securities  through  electronic
computerized  book-entry changes in  Participants' accounts, thereby eliminating
the need for physical movement  of securities certificates. Direct  Participants
include  securities  brokers  and  dealers,  banks,  trust  companies,  clearing
corporations and  certain other  organizations ("Direct  Participants"). DTC  is
owned by a number of its Direct Participants and by the New York Stock Exchange,
Inc. (the "New York Stock Exchange"), the American Stock Exchange, Inc., and the
National  Association of  Securities Dealers, Inc.  Access to the  DTC system is
also available to others such as securities brokers and dealers, banks and trust
companies that clear through or maintain a custodial relationship with a  Direct
Participant,  either directly or indirectly ("Indirect Participants"). The rules
applicable to DTC and its Participants are on file with the Commission.

    Purchases of Preferred Securities within the  DTC system must be made by  or
through  Direct  Participants, which  will receive  a  credit for  the Preferred
Securities on DTC's records. The ownership interest of each actual purchaser  of
each  Preferred Security ("Beneficial Owner")  is in turn to  be recorded on the
Direct and Indirect  Participants' records. Beneficial  Owners will not  receive
written  confirmation from  DTC of  their purchases,  but Beneficial  Owners are
expected to receive written confirmations providing details of the transactions,
as well as periodic  statements of their holdings,  from the Direct or  Indirect
Participants through which the Beneficial Owners purchased Preferred Securities.
Transfers  of  ownership  interests  in  the  Preferred  Securities  are  to  be
accomplished by entries made  on the books of  Participants acting on behalf  of
Beneficial  Owners. Beneficial Owners will not receive certificates representing
their ownership interests in Preferred Securities, except in the event that  use
of the book-entry system for the Preferred Securities is discontinued.

    DTC  has  no knowledge  of  the actual  Beneficial  Owners of  the Preferred
Securities; DTC's records reflect only  the identity of the Direct  Participants
to  whose accounts such Preferred Securities are  credited, which may or may not
be the Beneficial Owners. The  Participants will remain responsible for  keeping
account of their holdings on behalf of their customers.

    Conveyance   of  notices   and  other   communications  by   DTC  to  Direct
Participants, by Direct  Participants to  Indirect Participants,  and by  Direct
Participants  and Indirect Participants to Beneficial Owners will be governed by
arrangements among them, subject to any statutory or regulatory requirements  as
may be in effect from time to time.

    Redemption  notices shall  be sent  to Cede &  Co. If  less than  all of the
Preferred Securities are being redeemed, DTC's  practice is to determine by  lot
the  amount of  the interest  of each  Direct Participant  in such  series to be
redeemed.

    Although voting  with respect  to the  Preferred Securities  is limited,  in
those  cases where a  vote is required, neither  DTC nor Cede  & Co. will itself
consent  or  vote  with  respect  to  Preferred  Securities.  Under  its   usual
procedures,  DTC would  mail an  Omnibus Proxy  to COMSAT  Capital I  as soon as
possible after  the  record  date.  The  Omnibus  Proxy  assigns  Cede  &  Co.'s
consenting  or voting rights to those  Direct Participants to whose accounts the
Preferred Securities are credited  on the record date  (identified in a  listing
attached to the Omnibus Proxy).

    Dividend  payments on  the Preferred Securities  will be made  to DTC. DTC's
practice is to credit Direct Participants' accounts on the relevant payment date
in accordance with their respective holdings  shown on DTC's records unless  DTC
has  reason to believe that  it will not receive  payments on such payment date.
Payments by  Participants to  Beneficial  Owners will  be governed  by  standing
instructions  and customary  practices and  will be  the responsibility  of such
Participant and not of DTC, COMSAT Capital I or COMSAT, subject to any statutory
or   regulatory   requirements   as   may   be   in   effect   from   time    to

                                       16
<PAGE>
time.  Payment of dividends  to DTC is  the responsibility of  COMSAT Capital I,
disbursement of such payments  to Direct Participants  is the responsibility  of
DTC,  and  disbursement  of  such  payments  to  the  Beneficial  Owners  is the
responsibility of Direct and Indirect Participants.

    DTC may discontinue  providing its  services as  securities depository  with
respect  to the Preferred Securities at any  time by giving reasonable notice to
COMSAT Capital  I. Under  such  circumstances, in  the  event that  a  successor
securities  depository  is  not obtained,  Preferred  Security  certificates are
required to be printed and delivered.  Additionally, COMSAT Capital I (with  the
consent  of COMSAT) may  decide to discontinue  use of the  system of book-entry
transfers through DTC (or a  successor depository). In that event,  certificates
for the Preferred Securities will be printed and delivered. In each of the above
circumstances,  the General Partner will appoint  a paying agent with respect to
the Preferred Securities.

    The information in this section  concerning DTC and DTC's book-entry  system
has  been obtained from sources  that COMSAT and COMSAT  Capital I believe to be
reliable, but neither COMSAT nor COMSAT  Capital I takes responsibility for  the
accuracy thereof.

REGISTRAR AND TRANSFER AGENT

                  will  act as  registrar and  transfer agent  for the Preferred
Securities.

    Registration of transfers of Preferred  Securities will be effected  without
charge by or on behalf of COMSAT Capital I, but upon payment (with the giving of
such  indemnity as COMSAT Capital I or COMSAT may require) in respect of any tax
or other government charges which may be imposed in relation to it.

    COMSAT Capital I will not be required to register or cause to be  registered
the  transfer of Preferred Securities after  such Preferred Securities have been
called for redemption.

MISCELLANEOUS

    Application will be made  to list the Preferred  Securities on the New  York
Stock Exchange.

    The General Partner is authorized and directed to conduct its affairs and to
operate  COMSAT Capital I in such a way that COMSAT Capital I will not be deemed
to be an "investment company"  required to be registered  under the 1940 Act  or
taxed  as a corporation for federal income  tax purposes, and so that the Junior
Subordinated Debentures will be  treated as indebtedness  of COMSAT for  federal
income  tax purposes. In  this connection, the General  Partner is authorized to
take any  action,  not inconsistent  with  applicable law,  the  certificate  of
limited  partnership  or the  Limited  Partnership Agreement,  that  the General
Partner determines  in its  discretion to  be necessary  or desirable  for  such
purposes,  as long as such action does not adversely affect the interests of the
holders of the Preferred Securities.

    Holders of the Preferred Securities have no preemptive rights.

GOVERNING LAW

    COMSAT Capital I is  a limited partnership organized  in Delaware under  the
Delaware  Revised  Uniform  Limited  Partnership  Act.  The  Limited Partnership
Agreement and the Preferred Securities will be governed by Delaware law.

                                       17
<PAGE>
                          DESCRIPTION OF THE GUARANTEE

    SET FORTH BELOW IS A SUMMARY  OF INFORMATION CONCERNING THE GUARANTEE  WHICH
WILL  BE EXECUTED AND  DELIVERED BY COMSAT  FOR THE BENEFIT  OF THE HOLDERS FROM
TIME TO  TIME  OF PREFERRED  SECURITIES.  THE SUMMARY  DOES  NOT PURPORT  TO  BE
COMPLETE  AND IS SUBJECT IN ALL RESPECTS  TO THE PROVISIONS OF, AND IS QUALIFIED
IN ITS ENTIRETY BY REFERENCE TO, THE GUARANTEE, WHICH IS FILED AS AN EXHIBIT  TO
THE REGISTRATION STATEMENT OF WHICH THIS PROSPECTUS FORMS A PART.

GENERAL

    Pursuant  to  the  Guarantee, COMSAT  will  irrevocably  and unconditionally
agree, to the extent  set forth herein, to  pay in full, to  the holders of  the
Preferred  Securities, the  Guarantee Payments (as  defined below),  as and when
due, regardless of any  defense, right of set-off  or counterclaim which  COMSAT
Capital  I  may have  or  assert. The  following  payments with  respect  to the
Preferred Securities, to the extent not paid by COMSAT Capital I (the "Guarantee
Payments"), will  be subject  to the  Guarantee (without  duplication): (i)  any
accrued  and unpaid  dividends which  are required to  be paid  on the Preferred
Securities, to the extent such dividends have been declared by COMSAT Capital  I
out  of moneys held by COMSAT Capital I and legally available therefor, (ii) the
Redemption Price, payable out of  funds legally available therefor with  respect
to  any Preferred Securities called for redemption by COMSAT Capital I and (iii)
upon a liquidation of COMSAT Capital I,  the lesser of (a) the aggregate of  the
liquidation  preference and  all accrued and  unpaid dividends  on the Preferred
Securities to the date of payment and (b) the amount of assets of COMSAT Capital
I remaining available  for distribution  to holders of  Preferred Securities  in
liquidation of COMSAT Capital I. COMSAT's obligation to make a Guarantee Payment
may  be satisfied  by direct payment  of the  required amounts by  COMSAT to the
holders of  Preferred Securities  or by  causing COMSAT  Capital I  to pay  such
amounts to such holders.

    If  COMSAT  fails  to  make interest  payments  on  the  Junior Subordinated
Debentures  purchased  by  COMSAT  Capital   I,  COMSAT  Capital  I  will   have
insufficient  funds to pay dividends on  the Preferred Securities. The Guarantee
does not cover payment of dividends or the Redemption Price when COMSAT  Capital
I does not have sufficient funds to pay such dividends or Redemption Price.

    Because  the  Guarantee is  a guarantee  of payment  and not  of collection,
holders of  the Preferred  Securities  may proceed  directly against  COMSAT  as
guarantor,  rather  than  having  to proceed  against  COMSAT  Capital  I before
attempting to collect  from COMSAT,  and COMSAT waives  any right  or remedy  to
require  that any action be brought against COMSAT Capital I or any other person
or entity  before  proceeding  against  COMSAT. Such  obligations  will  not  be
discharged except by payment of the Guarantee Payments in full.

CERTAIN COVENANTS OF COMSAT

    In  the  Guarantee, COMSAT  will  covenant that,  so  long as  any Preferred
Securities remain outstanding, COMSAT will not  declare or pay any dividend  on,
or  redeem, purchase, acquire or make a liquidation payment with respect to, any
of its capital stock (other  than as a result  of a reclassification of  capital
stock  or the exchange or conversion of one class or series of capital stock for
another class or  series of capital  stock) or make  any guarantee payment  with
respect  to the foregoing if at such time (i) COMSAT has exercised its option to
defer interest payments on the Junior Subordinated Debentures and such  deferral
is  continuing, (ii) COMSAT shall  be in default with  respect to its payment or
other obligations under  the Guarantee or  (iii) there shall  have occurred  any
event  that, with  the giving  of notice  or the  lapse of  time or  both, would
constitute an Event of Default under the Indenture.

    COMSAT will also covenant that, so  long as any of the Preferred  Securities
are  outstanding, it will (i) maintain  direct 100% ownership of the partnership
interests in COMSAT  Capital I other  than the Preferred  Securities (except  as
permitted  in the Limited Partnership Agreement), (ii)  cause at least 3% of the
total value of COMSAT Capital I and at least 3% of all interest in the  capital,
income,  gain, loss,  deduction and  credit of  COMSAT Capital  I to  be held by
COMSAT, as General Partner, (iii) not voluntarily dissolve, wind-up or liquidate
itself or COMSAT Capital I, (iv)  remain the General Partner and timely  perform
all  of its duties as General Partner of COMSAT Capital I (including the duty to
cause COMSAT

                                       18
<PAGE>
Capital I to declare  and pay dividends on  the Preferred Securities), unless  a
permitted  successor General Partner is appointed,  and (v) subject to the terms
of the Preferred Securities, use reasonable efforts to cause COMSAT Capital I to
remain a Delaware limited partnership and  otherwise continue not to be  treated
as  an association taxable as a corporation for United States federal income tax
purposes,  except,  in   all  cases,   in  connection   with  certain   mergers,
consolidations  or amalgamations permitted by the Limited Partnership Agreement.
See "Description  of  the  Preferred  Securities  --  Merger,  Consolidation  or
Amalgamation of COMSAT Capital I".

AMENDMENTS AND ASSIGNMENT

    Except  with respect to any changes which do not adversely affect the rights
of holders of Preferred Securities (in which case no vote will be required), the
Guarantee may be changed only with the prior approval of the holders of not less
than 66 2/3% in liquidation preference of the outstanding Preferred  Securities.
The manner of obtaining any such approval of holders of the Preferred Securities
will  be as set forth  under "Description of the  Preferred Securities -- Voting
Rights". All guarantees and agreements contained in the Guarantee shall bind the
successors, assigns, receivers, trustees and representatives of COMSAT and shall
inure  to  the  benefit  of  the  holders  of  the  Preferred  Securities   then
outstanding.  Except in  connection with any  merger or  consolidation of COMSAT
with or into another entity or any sale, transfer or lease of COMSAT's assets to
another entity complying with the provisions under "-- Consolidation, Merger  or
Sale  of  Assets"  below, COMSAT  may  not  assign its  rights  or  delegate its
obligations under the Guarantee without the prior approval of the holders of not
less than  66 2/3%  of the  aggregate liquidation  preference of  the  Preferred
Securities then outstanding.

TERMINATION OF THE GUARANTEE

    The Guarantee will terminate and be of no further force and effect as to the
Preferred  Securities upon full payment of the Redemption Price of all Preferred
Securities, and  will terminate  completely  upon full  payment of  the  amounts
payable  upon liquidation of COMSAT Capital I. The Guarantee will continue to be
effective or will be reinstated, as the case  may be, if at any time any  holder
of  Preferred  Securities  must restore  payment  of  any sums  paid  under such
Preferred Securities or the Guarantee.

CONSOLIDATION, MERGER OR SALE OF ASSETS

    The Guarantee provides  that COMSAT may  merge or consolidate  with or  into
another  entity, may permit another entity to  merge or consolidate with or into
COMSAT and may sell, transfer or lease all or substantially all of its assets to
another entity, if (i) at such time no Event of Default shall have occurred  and
be continuing, or would occur as a result of such merger, consolidation or sale,
transfer  or lease  and (ii)  the survivor  of such  merger or  consolidation or
entity to  which COMSAT  assets are  sold, transferred  or leased  is an  entity
organized under the laws of the United States of America or any state thereof or
the  District of Columbia, becomes the  General Partner, assumes all of COMSAT's
obligations under the Guarantee and has a net worth equal to at least 10% of the
total contributions to COMSAT Capital I.

STATUS OF THE GUARANTEE -- SUBORDINATION

    The Guarantee will  constitute an  unsecured obligation of  COMSAT and  will
rank  (i)  subordinate and  junior in  right  of payment  to all  liabilities of
COMSAT, (ii) PARI PASSU with the  most senior preferred or preference stock  now
or  hereafter issued by COMSAT  and with any guarantee  now or hereafter entered
into by COMSAT  in respect  of any preferred  or preference  stock or  preferred
securities  of  any affiliate  of COMSAT,  and (iii)  senior to  COMSAT's common
stock. The Limited Partnership Agreement provides that each holder of  Preferred
Securities  by  acceptance thereof  agrees to  the subordination  provisions and
other terms of the Guarantee. Upon the bankruptcy, liquidation or winding-up  of
COMSAT,  its obligations under the  Guarantee will rank junior  to all its other
liabilities (except that  such obligations  will rank PARI  PASSU with  COMSAT's
obligations  under  any guarantee  now or  hereafter entered  into by  COMSAT in
respect of any  preferred or  preference stock  or preferred  securities of  any
affiliate  of COMSAT)  and, therefore,  funds may  not be  available for payment
under the  Guarantee. As  of  March 31,  1995,  COMSAT had  approximately  $1.15
billion  of indebtedness or  other obligations which  effectively rank senior to
the Guarantee and no indebtedness that would rank equally with the Guarantee.

                                       19
<PAGE>
    The Guarantee will constitute a guarantee of payment and not of  collection.
The  Guarantee will  be deposited with  the General  Partner to be  held for the
benefit of  the  holders  of the  Preferred  Securities.  In the  event  of  the
appointment  of a  Special Representative  to, among  other things,  enforce the
Guarantee, the Special Representative may  take possession of the Guarantee  for
such  purpose. If  no Special Representative  has been appointed  to enforce the
Guarantee, the General Partner has the right to enforce the Guarantee on  behalf
of  the holders of the Preferred Securities. The holders of not less than 10% in
aggregate liquidation preference  of all outstanding  Preferred Securities  have
the  right to direct the time, method and place of conducting any proceeding for
any remedy  available in  respect  of the  Guarantee,  including the  giving  of
directions to the General Partner or the Special Representative, as the case may
be.  If the General Partner  or the Special Representative  fails to enforce the
Guarantee as above provided, any holder of Preferred Securities may institute  a
legal  proceeding  directly  against  COMSAT to  enforce  its  rights  under the
Guarantee, without first instituting a legal proceeding against COMSAT Capital I
or any other person or  entity. The Guarantee will  not be discharged except  by
payment  of the  Guarantee Payments  in full  to the  extent not  paid by COMSAT
Capital I and by complete performance of all obligations under the Guarantee.

GOVERNING LAW

    The Guarantee will be governed by and construed in accordance with the  laws
of the State of New York.

                                       20
<PAGE>
               DESCRIPTION OF THE JUNIOR SUBORDINATED DEBENTURES

    SET  FORTH  BELOW IS  A  DESCRIPTION OF  THE  SPECIFIC TERMS  OF  THE JUNIOR
SUBORDINATED DEBENTURES IN WHICH COMSAT CAPITAL I WILL INVEST WITH THE  PROCEEDS
OF  THE ISSUANCE AND SALE  OF (I) THE PREFERRED  SECURITIES AND (II) THE GENERAL
PARTNER'S CAPITAL CONTRIBUTION  WITH RESPECT  TO THE  PREFERRED SECURITIES  (THE
"GENERAL PARTNERSHIP PAYMENT"). THE FOLLOWING DESCRIPTION DOES NOT PURPORT TO BE
COMPLETE  AND IS QUALIFIED  IN ITS ENTIRETY  BY REFERENCE TO  THE INDENTURE (THE
"INDENTURE"), DATED AS OF         , 1995, BETWEEN COMSAT  AND              ,  AS
TRUSTEE  (THE  "TRUSTEE"), THE  FORM  OF WHICH  IS FILED  AS  AN EXHIBIT  TO THE
REGISTRATION  STATEMENT  OF  WHICH  THIS  PROSPECTUS  FORMS  A  PART.   WHENEVER
PARTICULAR  PROVISIONS OR DEFINED TERMS IN THE INDENTURE ARE REFERRED TO HEREIN,
SUCH PROVISIONS OR DEFINED TERMS  ARE INCORPORATED BY REFERENCE HEREIN.  SECTION
AND ARTICLE REFERENCES USED HEREIN ARE REFERENCES TO PROVISIONS OF THE INDENTURE
UNLESS OTHERWISE NOTED.

    Under  certain circumstances involving  the dissolution of  COMSAT Capital I
following the occurrence  of a  Tax Event  or Investment  Company Event,  Junior
Subordinated  Debentures  may be  distributed to  the  holders of  the Preferred
Securities in liquidation of COMSAT Capital I. See "Description of the Preferred
Securities -- Tax Event or Investment Company Event Redemption or Distribution".

GENERAL

    The Junior Subordinated  Debentures will  be issued  as a  series of  Junior
Subordinated  Debentures under the Indenture. The Junior Subordinated Debentures
will be limited in  aggregate principal amount  to approximately $      million,
such  amount being the sum of the aggregate stated liquidation preference of the
Preferred Securities and the General Partnership Payment. The Indenture does not
limit the aggregate principal amount of Junior Subordinated Debentures which may
be issued thereunder and provides that the Junior Subordinated Debentures may be
issued thereunder from time to time in one or more series.

    The entire  principal  amount of  the  Junior Subordinated  Debentures  will
become  due and payable, together with  any accrued and unpaid interest thereon,
including Additional Interest, if any, on        , 2025, subject to the election
of COMSAT to extend the maturity date of the Junior Subordinated Debentures to a
date not later  than           , 2044,  provided that  COMSAT satisfies  certain
financial covenants. See "-- Option to Extend Maturity Date".

    The  Junior Subordinated Debentures, if  distributed to holders of Preferred
Securities in a dissolution of COMSAT Capital  I, will initially be issued as  a
Global  Security. In the event that Junior Subordinated Debentures are issued in
certificated form, such Junior Subordinated Debentures will be in  denominations
of $25 and integral multiples thereof and may be transferred or exchanged at the
offices described below.

    Payments  on Junior Subordinated Debentures issued as a Global Security will
be made to DTC, as the depository for the Junior Subordinated Debentures. In the
event Junior Subordinated Debentures are issued in certificated form,  principal
and interest will be payable, the transfer of the Junior Subordinated Debentures
will  be registrable and Junior Subordinated Debentures will be exchangeable for
Junior Subordinated  Debentures  of  other denominations  of  a  like  aggregate
principal amount at the corporate trust office of the Trustee in The City of New
York;  provided, that,  unless the  Junior Subordinated  Debentures are  held by
COMSAT Capital  I  or  any  successor  permissible  under  "Description  of  the
Preferred  Securities -- Merger, Consolidation or Amalgamation of COMSAT Capital
I", payment of interest may be made at  the option of COMSAT by check mailed  to
the address of the persons entitled thereto.

    If  the Junior  Subordinated Debentures  are distributed  to the  holders of
Preferred Securities upon the dissolution of  COMSAT Capital I, COMSAT will  use
its  best efforts  to list  the Junior Subordinated  Debentures on  the New York
Stock Exchange or on  such other exchange as  the Preferred Securities are  then
listed and traded on the same part of any such exchange.

                                       21
<PAGE>
    The  Indenture does not contain any provisions that afford holders of Junior
Subordinated  Debentures  protection  in  the   event  of  a  highly   leveraged
transaction involving COMSAT.

INTEREST

    Each  Junior Subordinated Debenture will bear interest at  the rate of     %
per annum from the original date of issuance, payable monthly in arrears on  the
last day of each calendar month of each year (each, an "Interest Payment Date"),
commencing         , 1995,  to the person in whose name such Junior Subordinated
Debenture is registered, subject to certain exceptions, at the close of business
on the  Business  Day  next  preceding such  Interest  Payment  Date;  provided,
however, that in the event the Junior Subordinated Debentures shall not continue
to  remain in book-entry-only form, COMSAT shall have the right to select record
dates which shall be more  than one Business Day  prior to the Interest  Payment
Date. Interest will compound monthly and will accrue at the annual rate of     %
on any interest installment not paid when due.

    The  amount of interest payable for any period will be computed on the basis
of a 360-day year of twelve 30-day months.  In the event that any date on  which
interest is payable on the Junior Subordinated Debentures is not a Business Day,
then  payment of  the interest  payable on such  date will  be made  on the next
succeeding day  which is  a Business  Day  (and without  any interest  or  other
payment  in respect of any such delay), except  that, if such Business Day is in
the next succeeding calendar year, such payment shall be made on the immediately
preceding Business Day, in each case with  the same force and effect as if  made
on such date.

OPTION TO EXTEND MATURITY DATE

    The  maturity date of the  Junior Subordinated Debentures is          , 2025
(the "Scheduled Maturity Date").  COMSAT, however, may,  prior to the  Scheduled
Maturity  Date, extend such  maturity date no more  than one time,  for up to an
additional 19 years from the Scheduled  Maturity Date, provided that (i)  COMSAT
is  not in bankruptcy or  otherwise insolvent, (ii) COMSAT  is not in default on
any series  of Junior  Subordinated  Debentures, (iii)  COMSAT has  made  timely
payments  on the Junior Subordinated Debentures for the immediately preceding 18
months without deferrals, (iv) COMSAT Capital I is not in arrears on payments of
distributions on Preferred  Securities, (v) the  Junior Subordinated  Debentures
shall  continue  to  pay interest  at  least at  a  rate  equal to  the  rate of
distributions  that  accrue  on  the  Preferred  Securities,  (vi)  the   Junior
Subordinated  Debentures  are  rated  Investment  Grade  by  Standard  &  Poor's
Corporation, Moody's Investors  Service, Inc., Fitch  Investor Services, Duff  &
Phelps  Credit  Rating Company  or any  other nationally  recognized statistical
rating organization, and  (vii) the  final maturity of  the Junior  Subordinated
Debentures  is  not later  than  the 49th  anniversary  of the  issuance  of the
Preferred Securities.

OPTION TO EXTEND INTEREST PAYMENT PERIOD

    COMSAT shall  have the  right at  any time  during the  term of  the  Junior
Subordinated  Debentures to extend the interest payment period from time to time
to a period not exceeding 60 consecutive months (the "Extension Period"), at the
end of which  Extension Period COMSAT  shall pay all  interest then accrued  and
unpaid  (together with  interest thereon  at the  rate specified  for the Junior
Subordinated Debentures to the extent permitted by applicable law). In no  event
shall any Extension Period extend beyond the maturity of the Junior Subordinated
Debentures.  During any  Extension Period, COMSAT  shall not declare  or pay any
dividend on, or  redeem, purchase, acquire  or make a  liquidation payment  with
respect  to, any  of its  capital stock.  Prior to  the termination  of any such
Extension Period,  COMSAT  may  further  extend  the  interest  payment  period,
provided  that such Extension Period together with all such previous and further
extensions thereof may not exceed 60 consecutive months. Upon the termination of
any Extension Period and the payment of all amounts then due, COMSAT may  select
a new Extension Period, subject to the above requirements. No interest during an
Extension Period, except at the end thereof, shall be due and payable. If COMSAT
Capital I shall be the sole holder of the Junior Subordinated Debentures, COMSAT
shall give COMSAT Capital I notice of its selection of such Extension Period one
Business Day prior to the earlier of (i) the date the dividends on the Preferred
Securities  are payable or  (ii) the date  COMSAT Capital I  is required to give
notice to the New York Stock Exchange

                                       22
<PAGE>
or other applicable self-regulatory organization or to holders of the  Preferred
Securities  of the record date or the date  such dividend is payable, but in any
event not less than  one Business Day  prior to such  record date. COMSAT  shall
cause  COMSAT Capital I to  give notice of COMSAT's  selection of such Extension
Period to the holders of the Preferred Securities. If COMSAT Capital I shall not
be the sole holder of the Junior Subordinated Debentures, COMSAT shall give  the
holders  of the Junior  Subordinated Debentures notice of  its selection of such
Extension Period ten  Business Days  prior to the  earlier of  (i) the  Interest
Payment  Date or (ii) the date COMSAT is required to give notice to the New York
Stock Exchange or other applicable  self-regulatory organization, or to  holders
of  the Junior Subordinated  Debentures, of the  record or payment  date of such
related interest payment, but in any event not less than two Business Days prior
to such record date.

ADDITIONAL INTEREST

    If at any time  COMSAT Capital I  shall be required to  pay any interest  on
dividends  in respect of the Preferred Securities pursuant to the terms thereof,
then COMSAT will pay as interest to COMSAT Capital I as the holder of the Junior
Subordinated Debentures ("Additional Interest") an amount equal to such interest
on dividends in arrears. In addition, if  COMSAT Capital I would be required  to
pay  any taxes, duties,  assessments or governmental  charges of whatever nature
(other than withholding taxes) imposed by the United States, or any other taxing
authority, then, in any such case,  COMSAT also will pay as Additional  Interest
such  amounts as shall be required so that the net amounts received and retained
by COMSAT  Capital  I  after  paying any  such  taxes,  duties,  assessments  or
governmental  charges will be not  less than the amounts  COMSAT Capital I would
have received had  no such  taxes, duties, assessments  or governmental  charges
been imposed.

MANDATORY PREPAYMENT

    If  COMSAT Capital  I redeems  Preferred Securities  in accordance  with the
terms thereof, the Junior Subordinated Debentures will become due and payable in
a principal amount equal to the  aggregate stated liquidation preference of  the
Preferred  Securities so redeemed, together with any accrued and unpaid interest
thereon, including Additional  Interest, if  any. Any payment  pursuant to  this
provision  shall be made prior to 12:00 noon, New York time, on the date of such
redemption or at  such other  time on  such earlier  date as  COMSAT and  COMSAT
Capital  I shall agree.  The Junior Subordinated Debentures  are not entitled to
the benefit of any sinking fund.

OPTIONAL REDEMPTION

    COMSAT shall have  the right  to redeem the  Junior Subordinated  Debentures
without  premium or penalty, in whole or in part, concurrent with the redemption
by COMSAT Capital I of the Preferred Securities (if any Preferred Securities are
then outstanding), at any time or from time to time on  or after        ,  2000,
upon not less than 30 nor more than 60 days' notice, at a redemption price equal
to  100% of  the principal  amount to  be redeemed  plus any  accrued and unpaid
interest, including Additional Interest, if any, to the redemption date.

    In the event of any redemption in part, COMSAT shall not be required to  (i)
issue,  register the transfer  of or exchange  any Junior Subordinated Debenture
during a  period  beginning  at the  opening  of  business 15  days  before  any
selection  for redemption  of Junior Subordinated  Debentures and  ending at the
close of  business  on  the  earliest  date in  which  the  relevant  notice  of
redemption  is deemed to have  been given to all  holders of Junior Subordinated
Debentures and (ii) register the transfer of or exchange any Junior Subordinated
Debentures so  selected  for  redemption,  in  whole  or  in  part,  except  the
unredeemed  portion of any Junior Subordinated Debenture being redeemed in part.
(Section 2.05).

SUBORDINATION

    The  Indenture  provides  that   the  Junior  Subordinated  Debentures   are
subordinate  and junior in right of payment to all Senior Indebtedness of COMSAT
as provided in the Indenture. No  payment of principal of (including  redemption
payments), or interest on, the Junior Subordinated Debentures may be made (i) if
any  Senior Indebtedness is not paid when  due, any applicable grace period with
respect to such default has ended and such default has not been cured or waived,
or (ii) if the maturity of any Senior

                                       23
<PAGE>
Indebtedness has been accelerated because of a default. Upon any distribution of
assets of COMSAT to creditors  upon any dissolution, winding-up, liquidation  or
reorganization,  whether voluntary or involuntary  or in bankruptcy, insolvency,
receivership or other proceedings,  all principal of, and  premium, if any,  and
interest  due or to become due on, all  Senior Indebtedness must be paid in full
before the holders of the Junior Subordinated Debentures are entitled to receive
or retain any  payment. The  rights of the  holders of  the Junior  Subordinated
Debentures   will  be  subrogated  to  the  rights  of  the  holders  of  Senior
Indebtedness  to  receive  payments   or  distributions  applicable  to   Senior
Indebtedness  until all amounts owing on  the Junior Subordinated Debentures are
paid in  full. (Sections  14.01 to  14.03). However,  since Senior  Indebtedness
currently  is not secured and ranks PARI PASSU with other unsecured indebtedness
of COMSAT, rights of  subrogation currently do not  improve the position of  the
holders  of the Junior Subordinated Debentures in relation to the holders of any
other unsecured indebtedness of COMSAT.

    The term "Senior Indebtedness" shall mean the principal of, premium, if any,
interest on and any other payment due pursuant to any of the following,  whether
outstanding  at the date  of execution of the  Indenture or thereafter incurred,
created  or  assumed:  (i)  all  indebtedness  of  COMSAT  evidenced  by  notes,
debentures,  bonds  or  other securities  sold  by  COMSAT for  money;  (ii) all
indebtedness of  others of  the  kinds described  in  the preceding  clause  (i)
assumed  by or  guaranteed in any  manner by  COMSAT or in  effect guaranteed by
COMSAT; and (iii) all renewals, extensions or refundings of indebtedness of  the
kinds described in any of the preceding clauses (i) and (ii); provided, however,
that   the  following  shall   not  constitute  Senior   Indebtedness:  (a)  any
indebtedness of COMSAT  to any subsidiary  of COMSAT, or  (b) any  indebtedness,
which  by the terms of the instrument  creating or evidencing the same expressly
provides that such indebtedness  is not superior  in right of  payment to or  is
PARI  PASSU with  the Junior  Subordinated Debentures.  Such Senior Indebtedness
shall continue to  be Senior Indebtedness  and entitled to  the benefits of  the
subordination  provisions irrespective of any  amendment, modification or waiver
of any term of such Senior Indebtedness. (Section 1.01).

    The Indenture does  not limit  the aggregate amount  of Senior  Indebtedness
which may be issued. At March 31, 1995, Senior Indebtedness of COMSAT aggregated
approximately $751 million.

CERTAIN COVENANTS OF COMSAT

    COMSAT  will covenant that  it will not  declare or pay  any dividend on, or
redeem, purchase, acquire  or make  a distribution or  liquidation payment  with
respect  to, any  of its  capital stock, if  at such  time (i)  there shall have
occurred any  event  that  would  constitute  an  Event  of  Default  under  the
Indenture,  (ii) COMSAT shall be  in default with respect  to its payment of any
obligations under the Guarantee or (iii)  COMSAT shall have given notice of  its
selection  of an extended  interest payment period as  provided in the Indenture
and such period, or any extension thereof, shall be continuing. (Section  4.06).
COMSAT  will also  covenant (i)  to remain  the sole  general partner  of COMSAT
Capital I  and maintain  100%  ownership of  the general  partnership  interests
thereof; provided that any permitted successor of COMSAT under the Indenture may
succeed  to COMSAT's duties as General Partner, (ii) to contribute capital in an
amount equal to at least 3% of the total capital contributions to COMSAT Capital
I, (iii) not  to voluntarily dissolve,  wind-up or terminate  COMSAT Capital  I,
except  in connection with the distribution of Junior Subordinated Debentures to
the holders of Preferred  Securities in liquidation of  COMSAT Capital I and  in
connection  with certain  mergers, consolidations or  amalgamations permitted by
the Limited Partnership Agreement, (iv) to  timely perform all of its duties  as
the  general partner in COMSAT Capital I (including the duty to pay dividends on
the Preferred Securities) and (v) to use its reasonable efforts to cause  COMSAT
Capital  I to  remain a  limited partnership  except in  connection with certain
mergers, consolidations or  amalgamations permitted by  the Limited  Partnership
Agreement  and otherwise continue not to be treated as an association taxable as
a corporation for United States federal income tax purposes. (Section 4.07).

EVENTS OF DEFAULT

    The Indenture  provides that  any one  or more  of the  following  described
events,  which has occurred and is continuing, constitutes an "Event of Default"
with respect to the Junior Subordinated  Debentures: (i) failure for 10 days  to
pay  interest on  the Junior  Subordinated Debentures,  including any Additional

                                       24
<PAGE>
Interest in  respect thereof,  when due;  or (ii)  failure to  pay principal  or
premium,  if  any, on  the Junior  Subordinated Debentures  when due  whether at
maturity, upon  redemption by  declaration  or otherwise;  or (iii)  failure  to
observe or perform any other covenant (other than those specifically relating to
another series of Junior Subordinated Debentures) contained in the Indenture for
90  days after  notice; or  (iv) the  dissolution, winding-up  or termination of
COMSAT  Capital  I,  except  in  connection  with  the  distribution  of  Junior
Subordinated Debentures to the holders of Preferred Securities in liquidation of
COMSAT  Capital  I and  in connection  with  certain mergers,  consolidations or
amalgamations permitted by  the Limited  Partnership Agreement;  or (v)  certain
events in bankruptcy, insolvency or reorganization of COMSAT. (Section 6.01).

    The  Trustee or the  holders of not  less than 25%  in aggregate outstanding
principal amount of the Junior Subordinated Debentures may declare the principal
of and interest (including any  Additional Interest) on the Junior  Subordinated
Debentures  due and payable immediately on  default with respect to such series;
provided, however, that after such acceleration, but before a judgment or decree
based on acceleration, the holders of  a majority in aggregate principal  amount
of  outstanding Junior Subordinated Debentures may, under certain circumstances,
rescind and annul  such acceleration if  all Events of  Default with respect  to
such  series, other  than the  non-payment of  accelerated principal,  have been
cured or waived as provided  in the Indenture. For  information as to waiver  of
defaults, see "-- Modification of the Indenture".

    COMSAT   Capital  I  is  the  initial  holder  of  the  Junior  Subordinated
Debentures. However,  while the  Preferred  Securities are  outstanding,  COMSAT
Capital I has agreed not to waive an Event of Default with respect to the Junior
Subordinated  Debentures without the consent of  holders of 66 2/3% in aggregate
liquidation preference of the Preferred  Securities then outstanding. A  default
under  any other indebtedness of COMSAT or COMSAT Capital I would not constitute
an Event of Default under the Junior Subordinated Debentures.

    Subject to the  provision of  the Indenture relating  to the  duties of  the
Trustee  in case an Event of Default  shall occur and be continuing, the Trustee
will be under no obligation  to exercise any of its  rights or powers under  the
Indenture  at the  request or  direction of  any holders  of Junior Subordinated
Debentures, unless such  holders shall  have offered to  the Trustee  reasonable
indemnity.  Subject to such  provisions for the  indemnification of the Trustee,
the holders of a majority in  aggregate principal amount of Junior  Subordinated
Debentures  then outstanding will have the right  to direct the time, method and
place of conducting any proceeding for  any remedy available to the Trustee,  or
exercising  any trust  or power  conferred on the  Trustee with  respect to such
series.

    No holder  of any  Junior  Subordinated Debenture  will  have any  right  to
institute  any  proceeding  with respect  to  the  Indenture or  for  any remedy
thereunder, unless  such  holder shall  have  previously given  to  the  Trustee
written  notice of a continuing Event of Default and, if COMSAT Capital I is not
the sole holder of Junior Subordinated Debentures, unless also the holders of at
least 25% in aggregate  principal amount of  the Junior Subordinated  Debentures
then  outstanding  shall  have  made  written  request,  and  offered reasonable
indemnity, to  the Trustee  to institute  such proceeding  as Trustee,  and  the
Trustee  shall not  have received  from the holders  of a  majority in aggregate
principal amount of the outstanding  Junior Subordinated Debentures a  direction
inconsistent  with  such  request  and  shall  have  failed  to  institute  such
proceeding within 60  days. However,  such limitations do  not apply  to a  suit
instituted  by a  holder of a  Junior Subordinated Debenture  for enforcement of
payment of the principal of or interest on such Junior Subordinated Debenture on
or after  the  respective  due  dates  expressed  in  such  Junior  Subordinated
Debenture (Sections 6.01 and 6.06).

    The  holders of a majority in  aggregate outstanding principal amount of all
series of the Junior Subordinated Debentures affected thereby may, on behalf  of
the  holders of all the Junior Subordinated Debentures of such series, waive any
past default, except a default in the payment of principal, premium, if any,  or
interest. (Section 6.06). COMSAT is required to file annually with the Trustee a
certificate as to whether or not COMSAT is in compliance with all the conditions
and covenants under the Indenture. (Section 5.03(d)).

                                       25
<PAGE>
ENFORCEMENT OF CERTAIN RIGHTS BY SPECIAL REPRESENTATIVE

    If  (i) COMSAT  Capital I fails  to pay  dividends in full  on the Preferred
Securities for 18 consecutive monthly dividend periods; (ii) an Event of Default
occurs and is continuing on the Junior Subordinated Debentures; or (iii)  COMSAT
is  in default on any  of its payment of  other obligations under the Guarantee,
under the  terms  of  the  Preferred  Securities,  the  holders  of  outstanding
Preferred  Securities will have the rights referred to under "Description of the
Preferred Securities -- Voting Rights", including the right to appoint a Special
Representative, which  Special Representative  shall be  authorized to  exercise
COMSAT  Capital  I's right  to  accelerate the  principal  amount of  the Junior
Subordinated Debentures and to enforce COMSAT Capital I's other creditor  rights
under the Junior Subordinated Debentures. Notwithstanding the appointment of any
such  Special Representative, COMSAT shall continue as General Partner and shall
retain all  rights  under the  Indenture,  including  the right  to  extend  the
interest  payment  period  from  time  to time  to  a  period  not  exceeding 60
consecutive months.

MODIFICATION OF THE INDENTURE

    The Indenture contains  provisions permitting COMSAT  and the Trustee,  with
the  consent of the holders  of not less than a  majority in principal amount of
the Junior Subordinated  Debentures of  each series  which are  affected by  the
modification,  to modify the  Indenture or any  supplemental indenture affecting
that series or the rights of the  holders of that series of Junior  Subordinated
Debentures;  provided, that no such modification may, without the consent of the
holder of each outstanding Junior  Subordinated Debenture affected thereby,  (i)
extend  the fixed maturity of any  Junior Subordinated Debentures of any series,
or reduce the principal amount thereof, or reduce the rate or extend the time of
payment of interest thereon, or reduce  any premium payable upon the  redemption
thereof, without the consent of the holder of each Junior Subordinated Debenture
so affected or (ii) reduce the percentage of Junior Subordinated Debentures, the
holders  of which  are required to  consent to any  such supplemental indenture,
without the consent of  the holders of each  Junior Subordinated Debenture  then
outstanding and affected thereby. (Section 9.02).

    In  addition, COMSAT and the Trustee may execute, without the consent of any
holder of Junior Subordinated Debentures, any supplemental indenture for certain
other usual  purposes  including  the  creation of  any  new  series  of  Junior
Subordinated Debentures. (Sections 2.01, 9.01 and 10.01).

CONSOLIDATION, MERGER OR SALE OF ASSETS

    The Indenture does not contain any covenant which restricts COMSAT's ability
to  merge or consolidate with or into  any other corporation, sell or convey all
or substantially  all  of its  assets  to any  person,  firm or  corporation  or
otherwise engage in restructuring transactions. (Section 10.01).

DEFEASANCE AND DISCHARGE

    Under the terms of the Indenture, COMSAT will be discharged from any and all
obligations  in respect  of the Junior  Subordinated Debentures  (except in each
case for certain  obligations to  register the  transfer or  exchange of  Junior
Subordinated  Debentures, replace stolen, lost  or mutilated Junior Subordinated
Debentures, maintain paying agencies  and hold moneys for  payment in trust)  if
COMSAT deposits with the Trustee, in trust, moneys or Government Obligations, in
an  amount sufficient to pay  all the principal of,  and interest on, the Junior
Subordinated Debentures on the  dates such payments are  due in accordance  with
the  terms of such Junior Subordinated  Debentures. Such defeasance or discharge
may occur only if, among  other things, COMSAT has  delivered to the Trustee  an
Opinion  of Counsel to  the effect that  COMSAT has received  from, or there has
been published by, the United States Internal Revenue Service a ruling, or there
has been a change in tax law in either case to the effect that holders of Junior
Subordinated Debentures will not recognize gain  or loss for federal income  tax
purposes  as a result of  such defeasance and will  be subject to federal income
tax on the same amount, in  the same manner and at  the same time as would  have
been the case if such defeasance was not to occur. (Sections 11.01 and 11.02).

                                       26
<PAGE>
SET-OFF

    Notwithstanding anything to the contrary in the Indenture, COMSAT shall have
the  right  to  set-off any  payment  with  respect to  the  Junior Subordinated
Debentures it is otherwise  required to make thereunder  with and to the  extent
COMSAT  has theretofore  made, or  is concurrently on  the date  of such payment
making, a payment under the Guarantee.

GOVERNING LAW

    The Indenture and the  Junior Subordinated Debentures  will be governed  by,
and  construed in accordance with,  the laws of the  State of New York. (Section
13.05).

INFORMATION CONCERNING THE TRUSTEE

    The Trustee, prior to default, undertakes to perform only such duties as are
specifically set forth in the Indenture  and, after default, shall exercise  the
same degree of care as a prudent individual would exercise in the conduct of his
or  her own affairs. (Section  7.01). Subject to such  provision, the Trustee is
under no obligation to exercise any of the powers vested in it by the  Indenture
at  the request of any holder  of Junior Subordinated Debentures, unless offered
reasonable indemnity by such holder against the costs, expenses and  liabilities
which  might be incurred thereby. (Section 7.02). The Trustee is not required to
expend or risk its own funds or otherwise incur personal financial liability  in
the  performance of its duties if the Trustee reasonably believes that repayment
or adequate indemnity is not reasonably assured to it. (Section 7.01).

                                       27
<PAGE>
                        EFFECT OF OBLIGATIONS UNDER THE
                JUNIOR SUBORDINATED DEBENTURES AND THE GUARANTEE

    As  set  forth in  the Limited  Partnership Agreement,  the sole  purpose of
COMSAT Capital  I is  to issue  the Preferred  Securities and  use the  proceeds
thereof to purchase from COMSAT the Junior Subordinated Debentures.

    As  long as payments of interest and other payments are made when due on the
Junior Subordinated  Debentures,  such  payments will  be  sufficient  to  cover
dividends and payments due on the Preferred Securities primarily because (i) the
aggregate  principal amount of  Junior Subordinated Debentures  will be equal to
the sum  of  the  aggregate  stated  liquidation  preference  of  the  Preferred
Securities  and  the General  Partnership Payment;  (ii)  the interest  rate and
interest and  other payment  dates on  the Junior  Subordinated Debentures  will
match  the dividend rate and dividend and  other payment dates for the Preferred
Securities; (iii) the  Limited Partnership  Agreement provides  that COMSAT,  as
General  Partner, shall pay for all, and COMSAT Capital I shall not be obligated
to pay, directly or indirectly, for any, costs and expenses of COMSAT Capital I;
and (iv) the  Limited Partnership  Agreement further provides  that the  General
Partner  shall not  cause or  permit COMSAT  Capital I  to, among  other things,
engage in  any activity  that is  not  consistent with  the purposes  of  COMSAT
Capital I.

    If   COMSAT  fails  to  make  interest  or  other  payments  on  the  Junior
Subordinated Debentures when due, the  Limited Partnership Agreement provides  a
mechanism whereby the holders of the Preferred Securities may enforce the rights
of  COMSAT  Capital  I  under the  Junior  Subordinated  Debentures  through the
appointment of  a  Special  Representative.  Payments  of  dividends  and  other
payments  due on the Preferred Securities out of moneys held by COMSAT Capital I
are guaranteed  by COMSAT  to the  extent set  forth under  "Description of  the
Guarantee".  The Limited Partnership Agreement  also provides, and COMSAT, under
the Guarantee, acknowledges, that a  Special Representative may be appointed  to
enforce  the Guarantee if COMSAT is in default on any of its payment obligations
under the  Guarantee.  In  addition,  if the  General  Partner  or  the  Special
Representative  fails to enforce the Guarantee, a holder of a Preferred Security
may institute a legal proceeding directly  against COMSAT to enforce its  rights
under  the Guarantee without first instituting a legal proceeding against COMSAT
Capital I or any other person or entity.

    COMSAT  and  COMSAT  Capital  I  believe  that  the  above  mechanisms   and
obligations,  taken  together,  are  substantially  equivalent  to  a  full  and
unconditional guarantee by COMSAT of payments due on the Preferred Securities.

                             UNITED STATES TAXATION

GENERAL

    This section  is a  summary  of certain  United  States federal  income  tax
considerations  that  may be  relevant  to prospective  purchasers  of Preferred
Securities and represents the opinion of  Crowell & Moring, special tax  counsel
to  COMSAT and  COMSAT Capital I,  insofar as it  relates to matters  of law and
legal conclusions. This section is based upon current provisions of the Internal
Revenue Code of 1986, as amended (the "Code"), existing and proposed regulations
thereunder and current administrative rulings and court decisions, all of  which
are  subject to  change. Subsequent changes  may cause tax  consequences to vary
substantially from the consequences described below. Moreover, the  transactions
described  in this Prospectus raise certain novel tax issues which have not been
ruled on by the courts  or the Internal Revenue  Service (the "IRS") in  similar
transactions. As a result, there can be no assurance that the IRS will not audit
these  transactions  and,  if it  does  so, that  the  IRS will  agree  with the
conclusions set forth below.

    No attempt  has been  made in  the following  discussion to  comment on  all
United  States  federal income  tax  matters affecting  purchasers  of Preferred
Securities. Moreover, the discussion focuses on holders of Preferred  Securities
who  are individual  citizens or  residents of  the United  States, who purchase
Preferred Securities at original issue for their initial offering price and  who
hold the Preferred

                                       28
<PAGE>
Securities as a capital asset, and has only limited application to corporations,
estates, trusts or, non-resident aliens or taxpayers having a taxable year other
than  the calendar  year. Accordingly,  each prospective  purchaser of Preferred
Securities should consult, and should depend on,  his or her own tax advisor  in
analyzing  the  federal,  state,  local  and  foreign  tax  consequences  of the
purchase, ownership or disposition of Preferred Securities.

TAX CLASSIFICATION

    Crowell &  Moring is  of  the opinion  that (i)  COMSAT  Capital I  will  be
classified  as a partnership for federal income tax purposes and (ii) the Junior
Subordinated Debentures will  be classified as  indebtedness for federal  income
tax purposes, although no assurances can be made in either regard. The following
discussion assumes such classifications.

INCOME FROM PREFERRED SECURITIES

    Each  holder of Preferred Securities  (a "Preferred Securityholder") will be
required to include in gross income the Preferred Securityholder's  distributive
share  of the net income of COMSAT Capital I. If COMSAT Capital I is merged into
a trust that is treated as  a grantor trust, each Preferred Securityholder  will
be  treated as owning  directly an allocable portion  of the Junior Subordinated
Debentures and as earning directly the income derived therefrom. In either case,
such income will  not exceed for  any calendar month  the dividends received  on
such  Preferred Securities, except  in limited circumstances  as described below
under "Original Issue  Discount" and  "Potential Extension  of Interest  Payment
Period".  Any amount  so included in  a Preferred  Securityholder's gross income
will increase  its tax  basis in  the Preferred  Securities, and  the amount  of
nonliquidating  distributions  of  cash  by  COMSAT  Capital  I  to  a Preferred
Securityholder will  reduce such  Preferred Securityholder's  tax basis  in  the
Preferred  Securities (but not  below zero). No  portion of such  income will be
eligible for the dividends received deduction.

ORIGINAL ISSUE DISCOUNT

    Under Treasury  Regulations,  the stated  interest  payments on  the  Junior
Subordinated  Debentures will be treated as "original issue discount" (sometimes
herein referred  to for  convenience as  interest) because  of the  option  that
COMSAT  has, under  the terms  of the  Junior Subordinated  Debentures, to defer
interest payments for  up to 60  months. Under  the Code, holders  of debt  with
original  issue discount  must include  that discount  in income  on an economic
accrual basis  and before  the  receipt of  cash  attributable to  the  interest
regardless  of  their method  of  tax accounting.  Except  to the  extent COMSAT
exercises its option  to defer  interest payments, the  characterization of  the
stated interest on the Junior Subordinated Debentures as original issue discount
will  not  affect  the  timing  or  amount  of  income  reportable  by Preferred
Securityholders. In  the  event  that interest  payments  are  deferred,  COMSAT
Capital  I will continue  to accrue income  equal to the  amount of the interest
payment due at the end of the Extension Period on an economic accrual basis over
the length of the Extension Period.

    Accrued  income  will  be  allocated,  but  not  distributed,  to  Preferred
Securityholders  of record on  the Business Day  preceding the last  day of each
calendar month. As  a result, owners  of Preferred Securities  on a record  date
during  an Extension Period will include interest  in gross income in advance of
the receipt  of cash,  and any  such Preferred  Securityholder who  disposes  of
Preferred  Securities  prior to  the record  date for  the payment  of dividends
following such  Extension Period  will include  such Preferred  Securityholder's
allocable  share of such interest in gross  income but will not receive any cash
related thereto.

    Holders of Junior  Subordinated Debentures  received upon  a liquidation  of
COMSAT  Capital I or  deemed to be  owned by the  Preferred Securityholders upon
merger of COMSAT Capital I into a trust  that is taxed as a grantor trust,  will
include in income interest on the Junior Subordinated Debentures as the interest
accrues (regardless of the Preferred Securityholder's method of accounting), and
thus will also recognize income in advance of the receipt of cash.

DISPOSITION OF PREFERRED SECURITIES

    Gain or loss will be recognized on a sale of Preferred Securities, including
a  redemption for cash, equal to the  difference between the amount realized and
the Preferred Securityholder's tax basis for the

                                       29
<PAGE>
Preferred Securities sold. Gain or loss recognized by a Preferred Securityholder
on the sale or exchange of a Preferred Security held for more than one year will
generally be taxable as long-term capital gain or loss.

    The adjusted  tax basis  of the  Preferred Securities  sold will  equal  the
amount  paid for the Preferred Securities, plus accrued original issue discount,
if any, as described herein allocated to the holder of such Preferred Securities
and reduced by any cash distributed  to such Preferred Securityholder by  COMSAT
Capital   I.  A  Preferred  Securityholder  acquiring  Preferred  Securities  at
different prices may  be required to  maintain a single  aggregate adjusted  tax
basis  in Preferred Securities, and,  upon sale or other  disposition of some of
the Preferred Securities,  allocate a  pro rata  portion of  such aggregate  tax
basis  to the Preferred Securities sold  (rather than maintaining a separate tax
basis in each Preferred  Security for purposes  of computing gain  or loss on  a
sale of such Preferred Security).

RECEIPT OF JUNIOR SUBORDINATED DEBENTURES UPON LIQUIDATION OR MERGER OF COMSAT
CAPITAL I

    Under  certain circumstances, as described under the caption "Description of
the Preferred Securities -- Tax Event or Investment Company Event Redemption  or
Distribution",  Junior Subordinated Debentures may be distributed to the holders
of the Preferred Securities  in liquidation of COMSAT  Capital I. Under  current
United  States federal income tax law, such a distribution would be treated as a
non-taxable exchange to each holder of Preferred Securities and would result  in
the  holder  of Preferred  Securities receiving  an aggregate  tax basis  in the
Junior Subordinated Debentures equal to such holder's aggregate tax basis in its
Preferred Securities.  A  holder's holding  period  in the  Junior  Subordinated
Debentures  so received  in liquidation  of COMSAT  Capital I  would include the
period for which the Preferred Securities were held by such holder. In addition,
a merger, consolidation or amalgamation of COMSAT Capital I into a trust that is
treated as a grantor trust would be treated in the same manner as a distribution
of the Junior Subordinated Debentures to the holders of the Preferred Securities
in liquidation of  COMSAT Capital I  followed by a  contribution of such  Junior
Subordinated Debentures to the grantor trust. Under a change in law, a change in
legal interpretation or the other circumstances giving rise to a Tax Event or an
Investment  Company Event, however, the dissolution  could be a taxable event to
holders of the Preferred Securities. In  the judgment of special tax counsel  to
COMSAT  and COMSAT  Capital I, the  series of  events which would  result in the
recognition of taxable gain or loss  by holders of the Preferred Securities,  by
reason  of a dissolution of COMSAT Capital I,  is not likely to occur. There can
be no assurance in this regard, however.

TAXATION OF HOLDERS OF GRANTOR TRUST INTERESTS

    If COMSAT Capital I is merged into  a trust treated as a grantor trust,  the
tax consequences of holding Successor Securities will differ in certain respects
from  the tax consequences of holding  Preferred Securities. In general, holders
of Successor Securities will be required  to include in gross income the  income
of the trust as such income accrues to the trust. A holder that includes amounts
in  income in  advance of  the receipt of  cash from  the grantor  trust may not
receive the cash from the  grantor trust related to  such income if such  holder
disposes  of its  Successor Securities  before the  record date  with respect to
payment of such amounts. A holder's  tax basis in the Successor Securities  will
be increased by the amount of any such accrued but unpaid income.

COMSAT CAPITAL INFORMATION RETURNS AND AUDIT PROCEDURES

    COMSAT,  as  the General  Partner  in COMSAT  Capital  I, will  furnish each
Preferred Securityholder  with  a Schedule  K-1  each year  setting  forth  such
Preferred  Securityholder's  allocable share  of income  for the  prior calendar
year. The Limited Partnership Agreement requires COMSAT to furnish such Schedule
K-1 as soon as practicable following the end of the year, but in any event prior
to March 31.  In the event  that COMSAT Capital  I is replaced  with a trust  as
previously described herein, investors will receive for tax reporting purposes a
Form 1099 instead of a Form K-1.

    Any person who holds Preferred Securities as a nominee for another person is
required  to furnish  to COMSAT  Capital I  (a) the  name, address  and taxpayer
identification number of the beneficial  owner and the nominee; (b)  information
as  to whether the beneficial owner is (i)  a person that is not a United States

                                       30
<PAGE>
person,  (ii)  a  foreign  government,  an  international  organization  or  any
wholly-owned  agency or instrumentality  of either of the  foregoing, or (iii) a
tax-exempt entity; (c) the amount and description of Preferred Securities  held,
acquired  or transferred for  the beneficial owner;  and (d) certain information
including the dates  of acquisitions  and transfers, means  of acquisitions  and
transfers,  and acquisition  cost for  purchases, as well  as the  amount of net
proceeds from sales. The nominee is required to supply the beneficial owners  of
the  Preferred Securities  with the information  furnished to  COMSAT Capital I.
Brokers  and  financial   institutions  are  required   to  furnish   additional
information,  including  whether  they  are United  States  persons  and certain
information on Preferred Securities they acquire, hold or transfer for their own
accounts. A penalty of $50 per failure (up to a maximum of $100,000 per calendar
year) is imposed by the Code for failure to report such information.

    The General Partner,  as the tax  matters partner, will  be responsible  for
representing the Preferred Securityholders in any dispute with the IRS. The Code
provides  for administrative examination of a  partnership as if the partnership
were a separate and distinct taxpayer. Generally, the statute of limitations for
partnership items does  not expire  before three years  after the  later of  the
filing  or the last date  for filing of the  partnership tax return (Form 1065),
determined without regard to extensions. The General Partner, as the tax matters
partner, will have authority to extend  the statute of limitations with  respect
to  partnership items for  the Preferred Securityholders  without their consent.
Any adverse determination following an audit  of the return of COMSAT Capital  I
by  the  appropriate taxing  authorities could  result in  an adjustment  of the
returns of the  Preferred Securityholders, and,  under certain circumstances,  a
Preferred  Securityholder may be precluded from separately litigating a proposed
adjustment to the items of the  partnership. An adjustment could also result  in
an  audit of  a Preferred Securityholder's  return and adjustments  of items not
related to the income and losses of COMSAT Capital I.

POTENTIAL EXTENSION OF INTEREST PAYMENT PERIOD

    Under the Indenture, COMSAT has  the right to extend  from time to time  the
interest  payment period on  the Junior Subordinated Debentures  to a period not
exceeding 60 consecutive months. In the  event that the interest payment  period
is extended, COMSAT Capital I will continue to accrue income equal to the amount
of  the interest payment due at the end  of the Extension Period, on an economic
basis over the length of the Extension Period. See "-- Original Issue Discount".

UNITED STATES ALIEN HOLDERS

    For purposes  of this  discussion, a  "United States  Alien Holder"  is  any
holder  who or  which is (i)  a nonresident  alien individual or  (ii) a foreign
corporation, partnership  or estate  or trust,  in either  case not  subject  to
United States federal income tax on a net income basis in respect of a Preferred
Security. This discussion is without regard to any income tax treaty that may be
applicable.

    Under  current  United  States  federal  income  tax  law,  subject  to  the
discussion below with respect to backup withholding:

        (i)  Payments by  COMSAT Capital I  or any of its  paying agents to  any
    holder  of a Preferred Security who or which is a United States Alien Holder
    will not be subject to United  States federal withholding tax provided  that
    (a)  the beneficial  owner of  the Preferred  Security does  not actually or
    constructively own 10%  or more of  the total combined  voting power of  all
    classes  of capital  stock of  COMSAT entitled  to vote,  (b) the beneficial
    owner of the Preferred Security is not a controlled foreign corporation that
    is related  to  COMSAT  through  stock ownership  and  (c)  either  (x)  the
    beneficial  owner of the Preferred Security certifies to COMSAT Capital I or
    its agent (generally on Form W-8 or a substitute therefor), under  penalties
    of  perjury, that it is  a United States Alien  Holder and provides its name
    and address or  (y) the  holder of the  Preferred Security  is a  securities
    clearing  organization,  bank  or  other  financial  institution  that holds
    customers' securities in  the ordinary course  of its trade  or business  (a
    "financial  institution"), and such holder certifies  to COMSAT Capital I or
    its agent under penalties of perjury  that such statement has been  received
    from the beneficial owner by it or by a financial institution between it and
    the beneficial owner and furnishes COMSAT Capital I or its agent with a copy
    thereof;

                                       31
<PAGE>
        (ii) a United States Alien Holder of a Preferred Security will generally
    not be subject to United States federal withholding tax on any gain realized
    on the sale or exchange of a Preferred Security; and

        (iii) a United States Alien Holder who is a nonresident alien individual
    present  in the United  States for 183 days  or more in  the taxable year of
    sale and who either has a "tax home" in the United States or with respect to
    whom certain other requirements are met,  is generally subject to a 30%  tax
    on  the amount  by which  his gross  gains from  the sale  of capital assets
    derived from U.S. sources exceed his gross losses from such sales.

    (An alien  individual  who  satisfies the  "substantial  presence  test"  of
    Section 7701(b)(3) of the Code, including an alien individual present in the
    United  States for 183 days or more in the calendar year, will be taxed as a
    resident alien individual, and not as a nonresident alien individual.)

BACKUP WITHHOLDING AND INFORMATION REPORTING

    In general, information  reporting requirements  will apply  to payments  to
noncorporate  United States  holders of  the proceeds  of the  sale of Preferred
Securities within the United  States and "backup withholding"  at a rate of  31%
will  apply to  such payments if  the United  States holder fails  to provide an
accurate taxpayer identification number.

    Payments of the proceeds from  the sale by a  United States Alien Holder  of
Preferred  Securities made to or through a  foreign office of a broker generally
will not be subject to information reporting or backup withholding, except that,
if the broker is  a United States person,  a controlled foreign corporation  for
United  States tax  purposes, or  a foreign  person 50%  or more  of whose gross
income is effectively  connected with a  United States trade  or business for  a
specified  three-year period, information reporting  may apply to such payments.
Payments of the  proceeds from the  sale by a  noncorporate holder of  Preferred
Securities  to or  through the United  States office  of a broker  is subject to
information reporting  and  possible backup  withholding  unless the  holder  or
beneficial  owner  certifies as  to its  non-United  States status  or otherwise
establishes an exemption from information reporting and backup withholding.

                                       32
<PAGE>
                                  UNDERWRITING

    Subject to the terms  and conditions of  the Underwriting Agreement,  COMSAT
Capital  I has agreed to sell to each  of the Underwriters named below, and each
of such Underwriters, for whom  Goldman, Sachs & Co.,  Smith Barney Inc. and  CS
First  Boston Corporation are acting as Representatives, has severally agreed to
purchase from COMSAT Capital  I, the respective  number of Preferred  Securities
set forth opposite its name below:

<TABLE>
<CAPTION>
                                                                                   NUMBER OF
                                                                                   PREFERRED
UNDERWRITER                                                                       SECURITIES
- - -------------------------------------------------------------------------------  -------------
<S>                                                                              <C>
Goldman, Sachs & Co............................................................
Smith Barney Inc...............................................................
CS First Boston Corporation....................................................

                                                                                 -------------
  Total........................................................................
                                                                                 -------------
                                                                                 -------------
</TABLE>

    Under   the  terms  and  conditions   of  the  Underwriting  Agreement,  the
Underwriters are committed to take and  pay for all of the Preferred  Securities
offered hereby, if any are taken.

    The  Underwriters propose to offer the Preferred Securities in part directly
to the public at the initial public  offering price set forth on the cover  page
of this Prospectus, and in part to certain securities dealers at such price less
a  concession of $  per Preferred Security. The Underwriters may allow, and such
dealers may reallow, a concession not in excess of $  per Preferred Security  to
certain  brokers and  dealers. After the  Preferred Securities  are released for
sale to the public, the offering price and other selling terms may from time  to
time be varied by the Representatives.

    In  view  of  the  fact that  the  proceeds  of the  sale  of  the Preferred
Securities will be used by COMSAT Capital I to purchase the Junior  Subordinated
Debentures,  the  Underwriting  Agreement  provides  that  COMSAT  will  pay  as
compensation to the Underwriters a commission of $  per Preferred Security.

    COMSAT and COMSAT  Capital I  have agreed not  to offer,  sell, contract  to
sell,  or otherwise  dispose of (a)  any limited partnership  interests or other
securities of  COMSAT Capital  I (other  than the  Preferred Securities  offered
hereby),  (b) any preferred  stock or any  other securities of  COMSAT which are
substantially similar to the Preferred Securities including the Guarantee, or to
the Junior  Subordinated  Debentures, or  (c)  any other  securities  which  are
convertible into, or exercisable or exchangeable for,

                                       33
<PAGE>
limited  partnership interests  in or other  securities of COMSAT  Capital I, or
preferred stock or such substantially similar securities of COMSAT, in any  such
case  for a  period of 90  days after the  date of this  Prospectus, without the
prior written consent of  the Representatives. Such  agreement will not  prevent
the  offer,  sale, contract  to sell,  or other  disposition of  the Convertible
Preferred  Securities,  or  of  the  related  guarantee  or  Convertible  Junior
Subordinated Debentures. See "Use of Proceeds".

    In  compliance with Section 34 of the Rules of Fair Practice of the National
Association  of  Securities  Dealers,  Inc.  ("NASD"),  no  sales  of  Preferred
Securities may be made by any NASD member to a discretionary account without the
prior written approval of the transaction by the customer.

    Prior  to this offering, there  has been no public  market for the Preferred
Securities. In order to meet one  of the requirements for listing the  Preferred
Securities  on the New  York Stock Exchange, the  Underwriters will undertake to
sell lots of 100  or more Preferred  Securities to a  minimum of 400  beneficial
holders.

    Trading  of  the Preferred  Securities  on the  New  York Stock  Exchange is
expected to commence within the seven-day  period after the initial delivery  of
the  Preferred  Securities. The  Representatives have  advised COMSAT  that they
intend to make  a market in  the Preferred Securities  prior to commencement  of
trading  on the New York Stock Exchange, but  are not obligated to do so and may
discontinue any such market making at any time without notice.

    COMSAT  Capital  I  and  COMSAT   have  agreed  to  indemnify  the   several
Underwriters  against  certain  liabilities,  including  liabilities  under  the
Securities Act.

    Certain of the Underwriters  engage in transactions with,  and from time  to
time  have performed services  for, COMSAT and its  subsidiaries in the ordinary
course of business.

                                    EXPERTS

    The consolidated financial  statements and the  related financial  statement
schedules  incorporated  in this  Prospectus by  reference from  COMSAT's Annual
Report on Form 10-K for the year  ended December 31, 1994, have been audited  by
Deloitte  & Touche LLP,  independent auditors, as stated  in their report (which
includes an  explanatory paragraph  referring to  the change  in its  method  of
accounting  for income  taxes), which is  incorporated herein  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.

                           VALIDITY OF THE SECURITIES

    The  validity  of  the Preferred  Securities,  the validity  of  the Limited
Partnership Agreement and  the formation of  COMSAT Capital I  are being  passed
upon  by Crowell & Moring,  special counsel to COMSAT  and COMSAT Capital I. The
validity of the Guarantee and the Junior Subordinated Debentures will be  passed
upon  on behalf of  COMSAT Capital I and  COMSAT by Warren  Y. Zeger, Esq., Vice
President, General Counsel  and Secretary of  COMSAT. As of  May    , 1995,  Mr.
Zeger  was the record owner  of        shares  of COMSAT's common stock ("Common
Stock") and had  options to purchase          shares of Common  Stock, of  which
options to purchase       shares were exercisable. The validity of the Preferred
Securities,  the Guarantee and the Junior Subordinated Debentures will be passed
upon for the Underwriters by Sullivan & Cromwell. Mr. Zeger will rely on Crowell
& Moring as to certain matters of  Delaware law. Statements as to United  States
taxation   in  this  Prospectus  in  the  second  paragraph  under  the  caption
"Investment Considerations -- Tax Event  or Investment Company Event  Redemption
or  Distribution", and  under the  caption "United  States Taxation",  have been
passed upon for COMSAT  and COMSAT Capital  I by Crowell  & Moring, special  tax
counsel  to  COMSAT  and  COMSAT  Capital I,  and  are  stated  herein  on their
authority.

                                       34
<PAGE>
- - --------------------------------------------------------------------------------
- - --------------------------------------------------------------------------------

    NO  PERSON  HAS BEEN  AUTHORIZED  TO GIVE  ANY  INFORMATION OR  TO  MAKE ANY
REPRESENTATIONS OTHER THAN THOSE CONTAINED IN  THIS PROSPECTUS AND, IF GIVEN  OR
MADE, SUCH INFORMATION OR REPRESENTATIONS MUST NOT BE RELIED UPON AS HAVING BEEN
AUTHORIZED.  THIS  PROSPECTUS  DOES  NOT  CONSTITUTE AN  OFFER  TO  SELL  OR THE
SOLICITATION OF AN  OFFER TO  BUY ANY SECURITIES  OTHER THAN  THE SECURITIES  TO
WHICH IT RELATES OR AN OFFER TO SELL OR THE SOLICITATION OF AN OFFER TO BUY SUCH
SECURITIES IN ANY CIRCUMSTANCES IN WHICH SUCH OFFER OR SOLICITATION IS UNLAWFUL.
NEITHER THE DELIVERY OF THIS PROSPECTUS NOR ANY SALE MADE HEREUNDER SHALL, UNDER
ANY  CIRCUMSTANCES, CREATE ANY IMPLICATION THAT THERE  HAS BEEN NO CHANGE IN THE
AFFAIRS OF  COMSAT  OR COMSAT  CAPITAL  I SINCE  THE  DATE HEREOF  OR  THAT  THE
INFORMATION CONTAINED HEREIN IS CORRECT AS OF ANY TIME SUBSEQUENT TO ITS DATE.

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

                               TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                    PAGE
                                                    -----
<S>                                              <C>
Available Information..........................           3
Incorporation of Certain Documents by
 Reference.....................................           3
COMSAT Capital I...............................           4
COMSAT Corporation.............................           4
Risk Factors...................................           6
Summary Financial Information of COMSAT........           8
Ratio of Earnings to Fixed Charges of COMSAT...           9
Use of Proceeds................................           9
Capitalization of COMSAT.......................           9
Description of the Preferred Securities........          10
Description of the Guarantee...................          18
Description of the Junior Subordinated
 Debentures....................................          21
Effect of Obligations Under the Junior
 Subordinated Debentures and the Guarantee.....          28
United States Taxation.........................          28
Underwriting...................................          33
Experts........................................          34
Validity of the Securities.....................          34
</TABLE>

                                  PREFERRED SECURITIES

                                COMSAT CAPITAL I

                                   % CUMULATIVE
                      MONTHLY INCOME PREFERRED SECURITIES
                            GUARANTEED TO THE EXTENT
                              SET FORTH HEREIN BY

                           [LOGO] COMSAT CORPORATION

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

                                   PROSPECTUS

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

                              GOLDMAN, SACHS & CO.

                               SMITH BARNEY INC.

                                CS FIRST BOSTON

                      REPRESENTATIVES OF THE UNDERWRITERS

- - --------------------------------------------------------------------------------
- - --------------------------------------------------------------------------------
<PAGE>
INFORMATION   CONTAINED  HEREIN  IS  SUBJECT   TO  COMPLETION  OR  AMENDMENT.  A
REGISTRATION STATEMENT  RELATING TO  THESE SECURITIES  HAS BEEN  FILED WITH  THE
SECURITIES  AND EXCHANGE  COMMISSION. THESE SECURITIES  MAY NOT BE  SOLD NOR MAY
OFFERS TO BUY BE ACCEPTED PRIOR  TO THE TIME THE REGISTRATION STATEMENT  BECOMES
EFFECTIVE.  THIS  PROSPECTUS  SHALL  NOT  CONSTITUTE AN  OFFER  TO  SELL  OR THE
SOLICITATION OF AN OFFER TO BUY NOR SHALL THERE BE ANY SALE OF THESE  SECURITIES
IN  ANY STATE IN WHICH SUCH OFFER,  SOLICITATION OR SALE WOULD BE UNLAWFUL PRIOR
TO REGISTRATION OR QUALIFICATION UNDER THE SECURITIES LAWS OF ANY SUCH STATE.
<PAGE>
                   SUBJECT TO COMPLETION, DATED JUNE 2, 1995
                                ,000,000 SHIPS-SM-

                               COMSAT Capital II
             % Share-linked Income Preferred Securities (SHIPS-SM-*)
              (LIQUIDATION PREFERENCE $50 PER PREFERRED SECURITY)
       GUARANTEED TO THE EXTENT SET FORTH HEREIN BY, AND CONVERTIBLE INTO
                                COMMON STOCK OF,
                           [LOGO] COMSAT Corporation

THE              %  SHARE-LINKED INCOME PREFERRED  SECURITIES (THE  "CONVERTIBLE
PREFERRED  SECURITIES")  REPRESENTING  THE  LIMITED  PARTNER  INTERESTS OFFERED
 HEREBY ARE BEING  ISSUED BY  COMSAT CAPITAL  II, L.P.,  A LIMITED  PARTNERSHIP
 FORMED UNDER THE LAWS OF THE STATE OF DELAWARE ("COMSAT CAPITAL II"). COMSAT
   CORPORATION,  A  DISTRICT  OF COLUMBIA  CORPORATION  ("COMSAT"),  IS THE
     GENERAL PARTNER IN COMSAT CAPITAL II (IN SUCH CAPACITY, THE  "GENERAL
      PARTNER").  COMSAT CAPITAL II EXISTS FOR THE SOLE PURPOSE OF ISSUING
      THE CONVERTIBLE PREFERRED SECURITIES AND USING THE PROCEEDS THEREOF
       TO PURCHASE FROM COMSAT ITS    % CONVERTIBLE JUNIOR  SUBORDINATED
        DEFERRABLE   INTEREST   DEBENTURES   (THE   "CONVERTIBLE  JUNIOR
        SUBORDINATED DEBENTURES"), HAVING THE TERMS DESCRIBED  HEREIN.
          THE   LIMITED   PARTNER  INTERESTS   REPRESENTED   BY  THE
            CONVERTIBLE PREFERRED SECURITIES WILL HAVE A  PREFERENCE
            WITH RESPECT TO CASH DISTRIBUTIONS AND AMOUNTS PAYABLE
              ON   LIQUIDATION   OVER   THE   GENERAL  PARTNER'S
                                 INTEREST IN COMSAT CAPITAL II.

                                                   (CONTINUED ON FOLLOWING PAGE)
                                 --------------

SEE "RISK FACTORS" ON  PAGE 10 OF  THIS PROSPECTUS FOR  A DISCUSSION OF  CERTAIN
FACTORS THAT
          SHOULD BE CONSIDERED IN CONNECTION WITH AN INVESTMENT IN THE
                           CONVERTIBLE PREFERRED
                                  SECURITIES.
                                 -------------

THESE  SECURITIES  HAVE  NOT  BEEN APPROVED  OR  DISAPPROVED  BY  THE SECURITIES
    AND  EXCHANGE  COMMISSION  OR   ANY  STATE  SECURITIES  COMMISSION   NOR
       HAS   THE  SECURITIES   AND  EXCHANGE  COMMISSION   OR  ANY  STATE
          SECURITIES  COMMISSION  PASSED  UPON  THE  ACCURACY  OR  AD-
              EQUACY   OF  THIS   PROSPECTUS.  ANY  REPRESENTATION
                       TO THE CONTRARY IS A CRIMINAL OFFENSE.

<TABLE>
<CAPTION>
                                                                               UNDERWRITING        PROCEEDS TO
                                                             PRICE TO         DISCOUNTS AND           COMSAT
                                                              PUBLIC           COMMISSIONS      CAPITAL II (1)(2)
                                                        ------------------  ------------------  ------------------
<S>                                                     <C>                 <C>                 <C>
PER CONVERTIBLE PREFERRED SECURITY....................        $50.00               (1)                $50.00
TOTAL (3).............................................          $                  (1)                  $
<FN>
(1)  IN VIEW  OF THE  FACT THAT  THE PROCEEDS  OF THE  SALE OF  THE  CONVERTIBLE
     PREFERRED  SECURITIES  WILL ULTIMATELY  BE  INVESTED IN  CONVERTIBLE JUNIOR
     SUBORDINATED DEBENTURES, THE  UNDERWRITING AGREEMENT  PROVIDES THAT  COMSAT
     WILL  PAY  TO THE  UNDERWRITERS, AS  COMPENSATION  FOR THEIR  ARRANGING THE
     INVESTMENT THEREIN OF  SUCH PROCEEDS,  $         PER CONVERTIBLE  PREFERRED
     SECURITY (OR $      IN THE AGGREGATE). SEE "UNDERWRITING".
(2)  EXPENSES  OF THE OFFERING WHICH  ARE PAYABLE BY COMSAT  ARE ESTIMATED TO BE
     $      .
(3)  COMSAT CAPITAL  II  AND COMSAT  HAVE  GRANTED THE  UNDERWRITERS  AN  OPTION
     EXERCISABLE  FOR 30  DAYS FROM  THE DATE OF  THIS PROSPECTUS  TO PURCHASE A
     MAXIMUM OF       ADDITIONAL CONVERTIBLE PREFERRED SECURITIES TO COVER OVER-
     ALLOTMENTS OF CONVERTIBLE PREFERRED SECURITIES. IF THE OPTION IS  EXERCISED
     IN  FULL, THE  TOTAL PRICE TO  PUBLIC WILL BE  $             , UNDERWRITING
     DISCOUNTS AND COMMISSIONS WILL BE $          AND PROCEEDS TO COMSAT CAPITAL
     II WILL BE $       .
</TABLE>

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

    THE CONVERTIBLE PREFERRED SECURITIES ARE OFFERED BY THE SEVERAL UNDERWRITERS
WHEN, AS AND IF ISSUED  BY COMSAT CAPITAL II, DELIVERED  TO AND ACCEPTED BY  THE
UNDERWRITERS AND SUBJECT TO THEIR RIGHT TO REJECT ORDERS IN WHOLE OR IN PART. IT
IS  EXPECTED THAT DELIVERY OF THE CONVERTIBLE PREFERRED SECURITIES IN BOOK-ENTRY
FORM WILL BE MADE THROUGH THE FACILITIES OF DTC ON OR ABOUT            , 1995.

- - ------------------
* SHIPS-SM- is a servicemark of CS First Boston Corporation.

CS First Boston
                              Goldman, Sachs & Co.
                                                               Smith Barney Inc.

               THE DATE OF THIS PROSPECTUS IS            , 1995.
<PAGE>
(CONTINUED FROM FRONT COVER)

    Holders of the Convertible Preferred Securities will be entitled to  receive
cumulative  cash  distributions at  an annual  rate of     % of  the liquidation
preference of $50 per Convertible Preferred Security, accruing from the date  of
original  issuance  and payable  monthly  in arrears  on  the last  day  of each
calendar month of  each year,  commencing                           , 1995.  See
"Description of the Convertible Preferred Securities--Dividends". The payment of
dividends  (but only if and to the extent  declared out of moneys held by COMSAT
Capital II  and legally  available  therefor), and  payments on  liquidation  of
COMSAT  Capital II or the redemption of Convertible Preferred Securities, as set
forth below,  are guaranteed  by  COMSAT to  the  extent described  herein  (the
"Guarantee").  COMSAT's  obligations  under the  Guarantee  are  subordinate and
junior in right  to all other  liabilities of COMSAT  (other than certain  other
guarantees).  See  "Description  of  the Guarantee".  If  COMSAT  fails  to make
interest payments  on the  Convertible  Junior Subordinated  Debentures,  COMSAT
Capital  II will  have insufficient  funds to  pay dividends  on the Convertible
Preferred Securities. The  Guarantee does  not cover payment  of dividends  when
COMSAT Capital II does not have sufficient funds to pay such dividends.

    COMSAT  has  the  right under  the  Indenture  (as defined  herein)  for the
Convertible Junior Subordinated Debentures to extend the interest payment period
from time to time on the Convertible Junior Subordinated Debentures to a  period
not exceeding 60 consecutive months, and, as a consequence, monthly dividends on
the Convertible Preferred Securities would be deferred by COMSAT Capital II (but
would  continue  to  accrue with  interest)  during any  such  extended interest
payment period. See  "Risk Factors--Option to  Extend Interest Payment  Period",
"Description   of   the   Convertible   Preferred   Securities--Dividends"   and
"Description of the Convertible Junior Subordinated Debentures--Option to Extend
Interest Payment Period".

    Each Convertible Preferred Security is  convertible in the manner  described
herein  at the option of the holder  into shares of COMSAT common stock, without
par value ("COMSAT Common Stock"), at  the rate of      shares of COMSAT  Common
Stock  for each Convertible Preferred Security (equivalent to a conversion price
of $     per  share of COMSAT  Common Stock), subject  to adjustment in  certain
circumstances. See "Description of the Convertible Preferred
Securities--Conversion  Rights". The last  reported sale price  of COMSAT Common
Stock, which is  listed under the  symbol "CQ"  on the New  York Stock  Exchange
("NYSE"),  on May 31, 1995, was $19 1/2  per share. See "Market Prices of COMSAT
Common Stock and Dividends".

    The Convertible Preferred Securities are redeemable at the option of  COMSAT
Capital  II, in whole or in part,  from time to time, on or  after             ,
        , at  $50 per  Convertible Preferred  Security plus  accrued and  unpaid
dividends  thereon (whether  or not  earned or declared)  to the  date fixed for
redemption  (the  "Redemption  Price").  See  "Description  of  the  Convertible
Preferred   Securities--Optional   Redemption".  Upon   the  repayment   of  the
Convertible Junior Subordinated Debentures at maturity or upon any acceleration,
earlier redemption  or  otherwise, the  proceeds  from such  repayment  will  be
applied to redeem the Convertible Preferred Securities.

    In  addition, upon the occurrence of certain events arising from a change in
law or a change  in legal interpretation,  the Convertible Preferred  Securities
are  redeemable in whole  at the Redemption  Price at the  option of the General
Partner, or the General Partner may dissolve  COMSAT Capital II and cause to  be
distributed  to the  holders of the  Convertible Preferred Securities,  on a pro
rata basis,  Convertible Junior  Subordinated  Debentures in  lieu of  any  cash
distribution.  If the Convertible Junior Subordinated Debentures are distributed
to the holders of the Convertible Preferred Securities, COMSAT will use its best
efforts to have  the Convertible  Junior Subordinated Debentures  listed on  the
NYSE  or on such other exchange as the Convertible Preferred Securities are then
listed. The  obligations of  COMSAT under  the Convertible  Junior  Subordinated
Debentures are subordinate and junior in right of payment to Senior Indebtedness
(as  defined herein) of COMSAT. At March 31, 1995, Senior Indebtedness of COMSAT
aggregated approximately  $751  million.  See "Description  of  the  Convertible
Preferred  Securities--Tax  Event  or  Investment  Company  Event  Redemption or
Distribution"  and   "Description  of   the  Convertible   Junior   Subordinated
Debentures".

    In  the event of  the liquidation of  COMSAT Capital II,  the holders of the
Convertible  Preferred  Securities  will  be   entitled  to  receive  for   each
Convertible  Preferred Security a liquidation preference of $50 plus accrued and
unpaid dividends thereon to the date of payment, subject to certain limitations,
unless, in  connection with  such liquidation,  Convertible Junior  Subordinated
Debentures   are  distributed  to  the  holders  of  the  Convertible  Preferred
Securities. See "Description of the Convertible Preferred
Securities--Liquidation Distribution Upon Dissolution".

    The Convertible  Preferred  Securities  will  be  represented  by  a  global
certificate  or  certificates registered  in the  name  of The  Depository Trust
Company  ("DTC")  or  its  nominee.  Beneficial  interests  in  the  Convertible
Preferred  Securities will be  shown on, and transfers  thereof will be effected
only through, records maintained by the participants in DTC. Except as described
herein, Convertible Preferred Securities in certificated form will not be issued
in exchange for the global certificate or certificates. See "Description of  the
Convertible Preferred Securities--Book-Entry-Only Issuance--The Depository Trust
Company".

    Application will be made to list the Convertible Preferred Securities on the
New York Stock Exchange.

                                       2
<PAGE>
                             AVAILABLE INFORMATION

    COMSAT  is  subject  to  the informational  requirements  of  the Securities
Exchange Act  of 1934,  as  amended (the  "Exchange  Act"), and,  in  accordance
therewith,  files  reports,  proxy  statements and  other  information  with the
Securities and  Exchange Commission  (the  "Commission"). These  reports,  proxy
statements  and  other information  can be  inspected and  copied at  the public
reference facilities maintained  by the  Commission at 450  Fifth Street,  N.W.,
Room 1024, Washington, D.C. 20549, as well as at the following Regional Offices:
7  World Trade Center,  New York, New  York 10048; and  500 West Madison Street,
Chicago, Illinois 60661. Copies of such material can be obtained from the Public
Reference Section of the Commission at 450 Fifth Street at prescribed rates  and
can be inspected at the New York, Chicago and Pacific Stock Exchanges.

    This  Prospectus  does not  contain  all the  information  set forth  in the
Registration Statement on Form  S-3 (together with  all amendments and  exhibits
thereto,  the "Registration  Statement") filed by  COMSAT Capital  II and COMSAT
with  the  Commission  under  the  Securities  Act  of  1933,  as  amended  (the
"Securities  Act"). Reference is made to  the Registration Statement for further
information with respect to COMSAT, COMSAT Capital II and the securities offered
hereby. Statements contained or incorporated by reference herein concerning  the
provisions  of documents are  necessarily summaries of  such documents, and each
statement is  qualified  in  its  entirety  by  reference  to  the  Registration
Statement.

    No  separate financial  statements of COMSAT  Capital II  have been included
herein. COMSAT  and  COMSAT Capital  II  do  not consider  that  such  financial
statements  would  be material  to holders  of Convertible  Preferred Securities
because COMSAT  Capital II  is a  newly formed  special purpose  entity, has  no
operating history, has no independent operations and is not engaged in, and does
not  propose to engage  in, any activity  other than as  set forth below. COMSAT
Capital II  is a  limited partnership  formed under  the laws  of the  State  of
Delaware. COMSAT is the sole general partner in COMSAT Capital II and, as of the
date hereof, directly or indirectly beneficially owns all of COMSAT Capital II's
partnership interests. See "COMSAT Capital II".

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

                INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

    COMSAT's  Annual Report on Form 10-K for  the fiscal year ended December 31,
1994, its Quarterly Report on Form 10-Q for the period ended March 31, 1995, and
its Current  Report on  Form  8-K filed  on  May 30,  1995,  as filed  with  the
Commission  pursuant to the Exchange Act,  are incorporated herein by reference.
All documents filed by COMSAT pursuant to Sections 13(a), 13(c), 14 or 15(d)  of
the  Exchange Act  subsequent to the  date of  this Prospectus and  prior to the
termination of the offering of the securities offered hereby shall be deemed  to
be  incorporated by reference into this Prospectus  and to be a part hereof from
the date  of filing  such documents.  Any  statement contained  herein or  in  a
document  all or a portion of which is incorporated or deemed to be incorporated
by reference herein shall be deemed to be modified or superseded for purposes of
this Prospectus to the extent that a statement contained herein or in any  other
subsequently  filed document which  also is or  is deemed to  be incorporated by
reference herein modifies or  supersedes such statement.  Any such statement  so
modified or superseded shall not be deemed, except as so modified or superseded,
to constitute a part of this Prospectus.

    COMSAT  hereby undertakes to provide without charge to each person to whom a
copy of this Prospectus has  been delivered, on the  written or oral request  of
any  such person, including  any beneficial owner, a  copy of any  or all of the
documents referred  to above  which have  been or  may be  incorporated in  this
Prospectus  by  reference, other  than exhibits  to  such documents  unless such
exhibits are specifically  incorporated by reference  into the information  that
the  Prospectus incorporates.  Requests for  such copies  should be  directed to
Nancy E.  Weber, Assistant  Secretary  of COMSAT,  at  6560 Rock  Spring  Drive,
Bethesda, MD 20817. Ms. Weber's telephone number is (301) 214-3643.

    IN  CONNECTION WITH THIS OFFERING, THE UNDERWRITERS MAY OVER-ALLOT OR EFFECT
TRANSACTIONS WHICH STABILIZE  OR MAINTAIN  THE MARKET PRICE  OF THE  CONVERTIBLE
PREFERRED  SECURITIES OFFERED  HEREBY AND  COMSAT COMMON  STOCK AT  LEVELS ABOVE
THOSE WHICH MIGHT OTHERWISE PREVAIL IN THE OPEN MARKET. SUCH TRANSACTIONS MAY BE
EFFECTED ON  THE NEW  YORK STOCK  EXCHANGE OR  OTHERWISE. SUCH  STABILIZING,  IF
COMMENCED, MAY BE DISCONTINUED AT ANY TIME.

                                       3
<PAGE>
                               PROSPECTUS SUMMARY

    THE FOLLOWING SUMMARY IS QUALIFIED IN ITS ENTIRETY BY, AND SHOULD BE READ IN
CONNECTION  WITH,  THE MORE  DETAILED INFORMATION  AND FINANCIAL  DATA APPEARING
ELSEWHERE OR  INCORPORATED  BY  REFERENCE  IN  THIS  PROSPECTUS,  INCLUDING  THE
INFORMATION UNDER "RISK FACTORS".

                               COMSAT CAPITAL II

    COMSAT  Capital II is a special  purpose limited partnership recently formed
under the laws of the  State of Delaware. All  of its partnership interests  are
owned  directly or indirectly by  COMSAT. COMSAT is the  sole general partner of
COMSAT Capital II. COMSAT Capital II exists for the sole purpose of issuing  the
Convertible  Preferred Securities and investing the proceeds thereof in COMSAT's
Convertible Junior Subordinated Debentures. The payment by COMSAT Capital II  of
dividends due on the Convertible Preferred Securities is solely dependent on its
receipt  of interest payments from COMSAT on the Convertible Junior Subordinated
Debentures.

                               COMSAT CORPORATION

    COMSAT is a global provider of communications and entertainment services and
products  primarily   operating  in   four  business   segments:   International
Communications, Mobile Communications, Entertainment and Technology Services.

    International   Communications  consists  of  COMSAT  World  Systems,  which
provides satellite communications  services using  the satellite  system of  the
International Telecommunications Satellite Organization ("INTELSAT"), and COMSAT
International   Ventures,  which  operates  and  invests  in  telecommunications
ventures  internationally.  Mobile  Communications  consists  of  COMSAT  Mobile
Communications,  which  provides  satellite  communications  services  using the
satellite  system   of   the   International   Mobile   Satellite   Organization
("Inmarsat").  Entertainment  consists  of  COMSAT  Entertainment  Group,  Inc.,
comprising COMSAT  Video  Enterprises,  Inc.  and  COMSAT's  majority  ownership
interest  in On Command Video  Corporation, which provide entertainment services
to the  hospitality industry  throughout the  United States  and domestic  video
distribution  services to a television network;  the Denver Nuggets, a franchise
of the  National  Basketball Association;  and  Beacon Communications  Corp.,  a
producer  of theatrical  films and  television programming.  Technology Services
consists of  COMSAT  RSI,  Inc., which  designs,  manufactures,  and  integrates
satellite  earth  stations,  advanced  antennas and  other  turnkey  systems for
telecommunications, radar, air traffic control  and military uses, and  provides
turnkey  voice,  video  and  data  communications  networks  and  products,  and
communication and  information  services  worldwide,  and  COMSAT  Laboratories,
COMSAT's center for applied research and technology development.

                              RECENT DEVELOPMENTS

    On  May 25, 1995, COMSAT Entertainment Group, Inc. announced an agreement to
buy  the  Quebec  Nordiques  National   Hockey  League  ("NHL")  franchise   for
approximately $75 million. COMSAT plans to transfer the team to Denver, Colorado
in  time for the 1995-96 NHL season.  The transaction and transfer fees, if any,
are subject to approval by the NHL Board of Governors.

                                  THE OFFERING

<TABLE>
<S>                                 <C>
Securities Offered................  of  COMSAT   Capital   II's             %   Share-linked
                                    Income   Preferred  Securities  ("Convertible  Preferred
                                    Securities"). Additionally, COMSAT Capital II and COMSAT
                                    have granted the Underwriters an  option for 30 days  to
                                    purchase  up  to  an additional              Convertible
                                    Preferred Securities  at  the  initial  public  offering
                                    price solely to cover over-allotments, if any.
</TABLE>

                                       4
<PAGE>

<TABLE>
<S>                                 <C>
Dividends.........................  Dividends  on the Convertible  Preferred Securities will
                                    be cumulative from the date of original issuance of  the
                                    Convertible  Preferred Securities and will be payable at
                                    the annual rate of      % of the liquidation  preference
                                    of  $50 per  Convertible Preferred  Security. Subject to
                                    the  dividend  deferral   provisions  described   below,
                                    dividends will be payable monthly in arrears on the last
                                    day  of each calendar month,  commencing         , 1995,
                                    when as and if available and determined to be so payable
                                    by COMSAT.

Dividend Deferral Provisions......  The ability of COMSAT Capital II to pay dividends on the
                                    Convertible Preferred Securities is solely dependent  on
                                    its  receipt  of interest  payments  from COMSAT  on the
                                    Convertible Junior Subordinated  Debentures. COMSAT  has
                                    the  right at any time, and from time to time, to extend
                                    the interest payment  period on  the Convertible  Junior
                                    Subordinated  Debentures  for  an  Extension  Period (as
                                    defined herein) not exceeding 60 consecutive months,  as
                                    described  below under  "Convertible Junior Subordinated
                                    Debentures -- Option to Extend Interest Payment Period".
                                    Monthly   dividends   on   the   Convertible   Preferred
                                    Securities  would be deferred by  COMSAT Capital II (but
                                    would continue to  accumulate monthly  and would  accrue
                                    interest)  during any such Extension Period. COMSAT will
                                    give written  notice of  its  extension of  an  interest
                                    payment  period to COMSAT  Capital II prior  to the last
                                    date on which it would be required to notify the NYSE of
                                    the record  or payment  date  of the  related  dividend,
                                    which  is  currently 10  days  prior to  such  record or
                                    payment date. COMSAT  shall cause COMSAT  Capital II  to
                                    give  such  notice  to the  holders  of  the Convertible
                                    Preferred Securities.  See "Risk  Factors --  Option  to
                                    Extend  Interest  Payment Period",  "Description  of the
                                    Convertible  Preferred  Securities  --  Dividends"   and
                                    "Description  of  the  Convertible  Junior  Subordinated
                                    Debentures --  Option  to Extend  Interest  Payment  Pe-
                                    riod".  If an  extension of  an interest  payment period
                                    occurs,  COMSAT  Capital  II,  except  in  very  limited
                                    circumstances, will continue to accrue income for United
                                    States  income tax purposes which will be allocated, but
                                    not distributed, to the holders of Convertible Preferred
                                    Securities  in   advance  of   any  corresponding   cash
                                    distribution.  See  "Risk  Factors --  Option  to Extend
                                    Interest Payment Period" and "United States Taxation  --
                                    Original Issue Discount".

Rights Upon Deferral of
 Dividends........................  During  any extension  of an interest  payment period on
                                    the Convertible Junior Subordinated Debentures, interest
                                    on the Convertible  Junior Subordinated Debentures  will
                                    compound  monthly and monthly  dividends (with interest)
                                    will accumulate on the Convertible Preferred Securities.
                                    COMSAT has agreed, among other things, not to declare or
                                    pay  any  dividend  on  its  Common  Stock  during   any
                                    Extension  Period. See  "Description of  the Convertible
                                    Preferred  Securities  --  Option  to  Extend   Interest
                                    Payment  Period"  and "Description  of the  Guarantee --
                                    Certain Covenants of COMSAT".
</TABLE>

                                       5
<PAGE>

<TABLE>
<S>                                 <C>
Conversion into COMSAT Common
 Stock............................  Each Convertible  Preferred Security  is convertible  at
                                    the  option of the  holder into shares  of COMSAT Common
                                    Stock, at the  rate of         shares  of COMSAT  Common
                                    Stock    for   each   Convertible   Preferred   Security
                                    (equivalent to a conversion price of $      per share of
                                    COMSAT Common Stock), subject  to adjustment in  certain
                                    circumstances.  The last  reported sale  price of COMSAT
                                    Common Stock on the NYSE Composite Tape on May 31, 1995,
                                    was $19 1/2 per share. In connection with any conversion
                                    of a  Convertible  Preferred  Security,  the  Conversion
                                    Agent (as defined herein) will exchange such Convertible
                                    Preferred  Security for the appropriate principal amount
                                    of the Convertible  Junior Subordinated Debentures  held
                                    by  COMSAT  Capital  II  and  immediately  convert  such
                                    Convertible Junior Subordinated  Debentures into  COMSAT
                                    Common   Stock.  See  "Description  of  the  Convertible
                                    Preferred Securities -- Conversion Rights".

Liquidation Preference............  In the event  of any dissolution  of COMSAT Capital  II,
                                    holders  will be entitled to receive $50 per Convertible
                                    Preferred Security, plus an amount equal to any  accrued
                                    and unpaid dividends thereon to the date of payment. See
                                    "Description  of the Convertible Preferred Securities --
                                    Liquidation Distribution Upon Dissolution".

Redemption........................  The Convertible Preferred Securities will be  redeemable
                                    for  cash, at the option of  COMSAT Capital II, in whole
                                    or in part, from  time to time,  on or after           ,
                                           ,  at the  Redemption Price  (as defined herein).
                                    The Convertible  Preferred Securities  will not  have  a
                                    stated  maturity date, although they  will be subject to
                                    mandatory  redemption   upon   the  repayment   of   the
                                    Convertible  Junior  Subordinated  Debentures  at stated
                                    maturity (         ,  2025), upon acceleration,  earlier
                                    redemption   or  otherwise.  See   "Description  of  the
                                    Convertible Preferred Securities -- Optional Redemption"
                                    and "-- Mandatory Redemption".

Guarantee.........................  COMSAT will  irrevocably  guarantee, on  a  subordinated
                                    basis and to the extent set forth herein, the payment in
                                    full  of (i) the dividends  on the Convertible Preferred
                                    Securities if and to the  extent declared from funds  of
                                    COMSAT  Capital II legally  available therefor, (ii) the
                                    Redemption Price of the Convertible Preferred Securities
                                    to the extent of  funds legally available therefor,  and
                                    (iii)  the  liquidation  preference  of  the Convertible
                                    Preferred Securities  to the  extent  of the  assets  of
                                    COMSAT  Capital II available for distribution to holders
                                    of Convertible Preferred Securities. The Guarantee  will
                                    be  unsecured  and  will  be  subordinate  to  all other
                                    liabilities of COMSAT  except for any  guarantee now  or
                                    hereafter  entered  into  by COMSAT  in  respect  of any
                                    preferred or preference stock or preferred securities of
                                    any affiliate of  COMSAT. The Guarantee  will rank  PARI
                                    PASSU  with the  most senior  preferred stock  issued by
                                    COMSAT. Upon the liquidation, dissolution or  winding-up
                                    of COMSAT, its obligations under the
</TABLE>

                                       6
<PAGE>

<TABLE>
<S>                                 <C>
                                    Guarantee   will  rank  junior  to   all  of  its  other
                                    liabilities (other than any  guarantee now or  hereafter
                                    entered  into by COMSAT  in respect of  any preferred or
                                    preference  stock   or  preferred   securities  of   any
                                    affiliate  of COMSAT)  and, therefore, funds  may not be
                                    available for  payment under  the Guarantee.  See  "Risk
                                    Factors  -- Subordination  of Guarantee  and Convertible
                                    Junior Subordinated Debentures", and "Description of the
                                    Guarantee".

Voting Rights.....................  Generally,  holders   of   the   Convertible   Preferred
                                    Securities  will not have any voting rights. However, if
                                    (i) COMSAT Capital II fails to pay dividends in full  on
                                    the  Convertible Preferred Securities for 18 consecutive
                                    months, (ii)  an Event  of Default  (as defined  herein)
                                    with  respect  to  the  Convertible  Junior Subordinated
                                    Debentures occurs  and is  continuing, or  (iii)  COMSAT
                                    defaults   under  the  Guarantee  with  respect  to  the
                                    Convertible Preferred  Securities,  the holders  of  the
                                    Convertible  Preferred  Securities will  be  entitled to
                                    appoint  and  authorize  a  Special  Representative  (as
                                    defined  herein) to  enforce COMSAT  Capital II's rights
                                    under the  Convertible Junior  Subordinated  Debentures,
                                    enforce  COMSAT's obligations  under the  Guarantee with
                                    respect to  the  Convertible  Preferred  Securities  and
                                    declare,  other than during an Extension Period, and pay
                                    dividends on the Convertible Preferred Securities to the
                                    extent funds of COMSAT Capital II are legally  available
                                    therefor.  See "Description of the Convertible Preferred
                                    Securities -- Voting Rights".

Tax Event or Investment Company
 Event Redemption or
 Distribution.....................  Upon the  occurrence of  a Tax  Event or  an  Investment
                                    Company  Event  (each, as  defined herein),  COMSAT will
                                    elect to  either (i)  redeem the  Convertible  Preferred
                                    Securities  in whole or (ii)  dissolve COMSAT Capital II
                                    and cause Convertible Junior Subordinated Debentures  to
                                    be   distributed  to  the  holders  of  the  Convertible
                                    Preferred Securities in connection with the  liquidation
                                    of COMSAT Capital II. In the case of a Tax Event, COMSAT
                                    may  also  elect  to  cause  the  Convertible  Preferred
                                    Securities to  remain  outstanding  and  pay  Additional
                                    Interest  (as defined herein)  on the Convertible Junior
                                    Subordinated  Debentures.   See  "Description   of   the
                                    Convertible   Preferred  Securities  --   Tax  Event  or
                                    Investment Company Event Redemption or Distribution".

Convertible Junior Subordinated
 Debentures.......................  The Convertible Junior Subordinated Debentures will  ma-
                                    ture  on          , 2025, and will  bear interest at the
                                    rate of       % per annum,  payable monthly in  arrears.
                                    Such payment period may be extended from time to time by
                                    COMSAT  (during which period  interest would continue to
                                    accrue and compound monthly) to an Extension Period  not
                                    exceeding   60   consecutive   months.   Prior   to  the
                                    termination of  any Extension  Period  of less  than  60
                                    consecutive   months,  COMSAT  may  further  extend  the
                                    interest  payment  period  as  long  as  such  Extension
                                    Period,   as   further   extended,   does   not   exceed
</TABLE>

                                       7
<PAGE>

<TABLE>
<S>                                 <C>
                                    60 consecutive  months and  does not  extend beyond  the
                                    stated   maturity   date  of   the   Convertible  Junior
                                    Subordinated Debentures.  Upon  the termination  of  any
                                    Extension  Period  and the  payment  of all  accrued and
                                    unpaid interest (including interest thereon), COMSAT may
                                    select a new Extension Period, subject to the  preceding
                                    sentence.  No interest  shall be due  during an extended
                                    interest payment period until the end of such period. If
                                    COMSAT extends an  interest payment period,  it will  be
                                    prohibited  from paying dividends on  any of its capital
                                    stock and making certain other restricted payments until
                                    monthly  interest   payments   are   resumed   and   all
                                    accumulated  and unpaid interest (including any interest
                                    thereon)  on   the   Convertible   Junior   Subordinated
                                    Debentures  is  brought  current.  The  payment  of  the
                                    principal of  and  interest on  the  Convertible  Junior
                                    Subordinated Debentures will be subordinated in right of
                                    payment  to all Senior Indebtedness (as defined herein).
                                    As of  March 31,  1995,  COMSAT had  approximately  $751
                                    million  of Senior Indebtedness.  The Convertible Junior
                                    Subordinated  Debentures  will   have  provisions   with
                                    respect  to interest, optional redemption and conversion
                                    into  COMSAT  Common  Stock  and  certain  other   terms
                                    substantially  similar  or  analogous  to  those  of the
                                    Convertible Preferred  Securities. See  "Description  of
                                    the  Convertible  Junior  Subordinated  Debentures"  and
                                    "Risk  Factors   --  Subordination   of  Guarantee   and
                                    Convertible Junior Subordinated Debentures".

Use of Proceeds...................  COMSAT Capital II will invest the proceeds received from
                                    the  sale of the Convertible Preferred Securities in the
                                    Convertible Junior  Subordinated Debentures  of  COMSAT.
                                    COMSAT  will use the net proceeds, together with the net
                                    proceeds from the  issuance of  its Junior  Subordinated
                                    Debentures  (as defined  herein), to  reduce outstanding
                                    indebtedness, approximately $75 million of which may  be
                                    incurred  in connection  with the purchase  by COMSAT of
                                    the Quebec  Nordiques  NHL franchise,  and  for  general
                                    corporate purposes. See "Use of Proceeds".

Form of Convertible Preferred Se-
 curities.........................  The Convertible Preferred Securities will be represented
                                    by  a global  certificate or  certificates registered in
                                    the name of Cede &  Co., as nominee for DTC.  Beneficial
                                    interests  in the Convertible  Preferred Securities will
                                    be evidenced by, and transfers thereof will be  effected
                                    only  through, records maintained by the participants in
                                    DTC. Except as  described herein, Convertible  Preferred
                                    Securities  in certificated  form will not  be issued in
                                    exchange for the global certificate or certificates. See
                                    "Description of the Convertible Preferred Securities  --
                                    Book-Entry-Only   Issuance   --  The   Depository  Trust
                                    Company".
</TABLE>

                                       8
<PAGE>
                    SUMMARY FINANCIAL INFORMATION OF COMSAT

    The selected data presented below under the caption "Income Statement  Data"
for  each of  the years  in the  three-year period  ended December  31, 1994 and
"Balance Sheet Data" as of December 31, 1994 and 1993 have been derived from the
consolidated financial statements of COMSAT, which have been audited by Deloitte
& Touche LLP, independent auditors. The selected consolidated "Income  Statement
Data"  for each of the years ended December 31, 1991 and 1990 and "Balance Sheet
Data" as of December 31, 1992, 1991 and 1990 are derived from audited  financial
statements  of  COMSAT not  included or  incorporated  by reference  herein. The
selected data presented below as of and for each of the quarters ended March 31,
1995 and 1994 have  been derived from the  consolidated financial statements  of
COMSAT,  which  have  not  been  audited, but  in  the  opinion  of  COMSAT such
information  includes  all  adjustments   consisting  of  normal  or   recurring
adjustments   necessary  for  a  fair  presentation  of  such  information.  The
consolidated financial statements as of December 31, 1994 and 1993, and for each
of the  years  in  the  three-year  period ended  December  31,  1994,  and  the
independent  auditors' report  thereon (which includes  an explanatory paragraph
referring to the change in its method  of accounting for income taxes), and  the
condensed  consolidated financial statements as of  and for each of the quarters
ended March  31, 1995  and  1994 and  Management's  Discussion and  Analysis  of
Financial  Condition and Results  of Operations ("MD&A")  for such periods, have
been incorporated by reference herein.  See "Incorporation of Certain  Documents
by  Reference".  The financial  information presented  below  should be  read in
conjunction with such  consolidated financial statements  and the notes  thereto
and such MD&A.

<TABLE>
<CAPTION>
                               QUARTER ENDED
                                 MARCH 31,
                                (UNAUDITED)                         YEAR ENDED DECEMBER 31,
                           ----------------------  ----------------------------------------------------------
                              1995        1994        1994        1993        1992        1991        1990
                           ----------  ----------  ----------  ----------  ----------  ----------  ----------
                                              (IN THOUSANDS, EXCEPT PER SHARE INFORMATION)
<S>                        <C>         <C>         <C>         <C>         <C>         <C>         <C>
INCOME STATEMENT DATA:
  Revenues...............  $  207,883  $  200,495  $  826,899  $  754,285  $  688,093  $  651,211  $  563,462
  Operating expenses.....     178,126     163,621     676,648     602,705     583,111     508,499     563,980
  Operating income
   (loss)................      29,757      36,874     150,251     151,580     104,982     142,712        (518)
  Income (loss) before
   cumulative effect of
   changes in accounting
   principles............      14,573      20,181      77,642      82,469      53,292      81,014      (9,045)
  Cumulative effect of
   changes in accounting
   principles............      --          --          --           1,925      --         (26,607)     --
  Net income (loss)......      14,573      20,181      77,642      84,394      53,292      54,407      (9,045)
  Dividends paid.........       9,178       7,446      33,547      30,410      27,837      25,867      25,219
  Primary earnings (loss)
   per share.............        0.31        0.43        1.64        1.79        1.16        1.22       (0.21)
  Dividends paid per
   share.................       0.195       0.185        0.76        0.74        0.70        0.67        0.66
BALANCE SHEET DATA:
  Total assets...........   2,017,219   1,975,992   1,975,992   1,773,513   1,654,985   1,469,516   1,300,683
  Long-term debt.........     569,440     515,542     515,542     410,550     496,804     391,308     383,695
  Stockholders' equity...     837,713     826,916     826,916     763,440     702,292     657,783     619,150
</TABLE>

                                       9
<PAGE>
                                  RISK FACTORS

    PROSPECTIVE  PURCHASERS OF CONVERTIBLE PREFERRED SECURITIES SHOULD CAREFULLY
REVIEW THE  INFORMATION  CONTAINED  ELSEWHERE  IN  THIS  PROSPECTUS  AND  SHOULD
PARTICULARLY CONSIDER THE FOLLOWING MATTERS:

SUBORDINATION OF GUARANTEE AND CONVERTIBLE JUNIOR SUBORDINATED DEBENTURES

    COMSAT's obligations under the Guarantee are subordinate and junior in right
of  payment  to  all  other  liabilities  of  COMSAT  except  for  certain other
guarantees that may be executed by COMSAT in respect of preferred securities  of
certain  affiliates of COMSAT.  The obligations of  COMSAT under the Convertible
Junior Subordinated Debentures described  under "Description of the  Convertible
Junior  Subordinated Debentures" are subordinate and  junior in right of payment
to Senior Indebtedness  of COMSAT.  At March  31, 1995,  Senior Indebtedness  of
COMSAT  aggregated  approximately  $751  million.  There  are  no  terms  in the
Convertible Preferred Securities, the Convertible Junior Subordinated Debentures
or the Guarantee that limit  COMSAT's ability to incur additional  indebtedness,
including  indebtedness that ranks senior to the Convertible Junior Subordinated
Debentures and the Guarantee. See "Description of the Guarantee -- Status of the
Guarantee" and "Description of the Convertible Junior Subordinated Debentures --
Subordination".

OPTION TO EXTEND INTEREST PAYMENT PERIOD

    COMSAT has the  right under  the Indenture  to extend  the interest  payment
period  from time to time on the Convertible Junior Subordinated Debentures to a
period not  exceeding 60  consecutive  months, and,  as a  consequence,  monthly
dividends  on the Convertible  Preferred Securities would  be deferred by COMSAT
Capital II (but would continue to accrue with interest thereon) during any  such
extended interest payment period. In the event that COMSAT exercises this right,
COMSAT  may not declare or pay dividends on, or redeem, purchase or acquire, any
of its capital  stock. Prior to  the termination of  any such extension  period,
COMSAT  may  further  extend the  interest  payment period,  provided  that such
extension period together with all such previous and further extensions  thereof
may  not exceed  60 consecutive  months. Upon  the termination  of any extension
period COMSAT is required to  pay all amounts then  due and, upon such  payment,
COMSAT  may select a new extension period, subject to the above requirements. In
no  event  shall  any  extension  period  extend  beyond  the  maturity  of  the
Convertible Junior Subordinated Debentures. COMSAT Capital II and COMSAT believe
that  the extension of  a payment period on  the Convertible Junior Subordinated
Debentures is unlikely. See "Description of the Convertible Preferred Securities
- - -- Dividends" and "Description of the Convertible Junior Subordinated Debentures
- - -- Option to Extend Interest Payment Period".

    Should an extended  interest payment  period occur, COMSAT  Capital II  will
continue  to accrue income  for United States federal  income tax purposes which
will be allocated,  but not  distributed, to  holders of  record of  Convertible
Preferred  Securities. As a result, such a  holder will include such interest in
gross income for  United States federal  income tax purposes  in advance of  the
receipt of cash, and will not receive the cash from COMSAT Capital II related to
such  income  if such  a holder  disposes  of his  or her  Convertible Preferred
Securities prior to the record date for payment of dividends. See "United States
Taxation -- Potential Extension of Interest Payment Period".

TAX EVENT OR INVESTMENT COMPANY EVENT REDEMPTION OR DISTRIBUTION

    Upon the occurrence of a Tax Event (as defined herein) or Investment Company
Event (as defined herein), the General  Partner will elect to either (i)  redeem
the Convertible Preferred Securities in whole or (ii) dissolve COMSAT Capital II
and  cause Convertible Junior  Subordinated Debentures to  be distributed to the
holders  of  the  Convertible  Preferred  Securities  in  connection  with   the
liquidation  of  COMSAT Capital  II. In  the case  of a  Tax Event,  the General
Partner may also elect to cause  the Convertible Preferred Securities to  remain
outstanding  and pay Additional Interest (as  defined herein) on the Convertible
Junior Subordinated Debentures. The  Convertible Junior Subordinated  Debentures
will  initially be issued at face value as a Global Security (as defined herein)
and will  be  limited in  aggregate  principal amount  to  approximately  $103.1
million,  such  amount  being  the  sum  of  the  aggregate  stated  liquidation
preference  of   the   Convertible   Preferred  Securities   and   the   General

                                       10
<PAGE>
Partnership  Payment (as  defined herein).  See "Description  of the Convertible
Preferred Securities  -- Tax  Event or  Investment Company  Event Redemption  or
Distribution" and "Description of the Convertible Junior Subordinated Debentures
- - -- General".

    Under  current United States  federal income tax law,  a distribution of the
Convertible Junior  Subordinated Debentures  would  not be  a taxable  event  to
holders of the Convertible Preferred Securities. Under a change in law, a change
in legal interpretation or the other circumstances giving rise to a Tax Event or
Investment  Company Event, however, the dissolution  could be a taxable event to
holders of the Convertible Preferred Securities. In the judgment of special  tax
counsel to COMSAT and COMSAT Capital II, the series of events which would result
in  the  recognition of  taxable  gain or  loss  by holders  of  the Convertible
Preferred Securities,  by  reason of  a  dissolution  of COMSAT  Capital  II  in
response to a Tax Event or Investment Company Event, is unlikely to occur. There
can  be no  assurance in  this regard, however.  See "United  States Taxation --
Receipt of Convertible Junior Subordinated Debentures Upon Liquidation of COMSAT
Capital II".

RESTRICTIONS ON OWNERSHIP, TRANSFER AND VOTING OF COMSAT COMMON STOCK

    The Satellite Act and COMSAT's Articles of Incorporation create a number  of
restrictions   on  the  rights  of  holders   of  COMSAT  capital  stock.  These
limitations, which affect certain communications common carriers, alien  persons
and  persons, syndicates or affiliated groups that own or hold more than 10% (or
5% in the case of voting rights)  of the aggregate number of outstanding  shares
of  COMSAT Common Stock, may  restrict the ability of  COMSAT to issue shares of
COMSAT Common Stock  to certain  persons in  connection with  the conversion  of
Convertible  Preferred Securities or  Convertible Junior Subordinated Debentures
into COMSAT Common Stock,  and may limit the  rights of certain shareholders  to
own, transfer and vote shares of COMSAT Common Stock. See "Description of COMSAT
Capital Stock -- General", "-- Restrictions on Ownership and Transfer of Shares"
and "-- Voting Rights; Election of Directors".

REPLACEMENT OF COMSAT CAPITAL II WITH A TRUST

    Subject  to certain conditions,  COMSAT Capital II has  the right to replace
COMSAT Capital  II with  a  trust as  the issuing  vehicle.  In the  event  such
replacement  is made, investors' rights in  the successor securities will remain
materially unchanged; however, investors will receive for tax reporting purposes
a Form 1099 instead of a Form K-1. It is expected that the Convertible Preferred
Securities and any such successor securities will be listed as equity securities
on  the  New  York  Stock  Exchange.  Accordingly,  the  Convertible   Preferred
Securities  are  expected to  trade "flat";  thus, purchasers  will not  pay and
sellers will not  receive any  accrued and  unpaid interest  on the  Convertible
Preferred  Securities or such  successor securities that is  not included in the
trading price. However, if  the replacement is made,  for United States  Federal
income  tax purposes,  interest on the  applicable successor  securities will be
included in  income  as it  accrues  (regardless  of the  method  of  accounting
otherwise  used), rather than when it is  allocated or paid. See "Description of
the Convertible Preferred Securities -- Merger, Consolidation or Amalgamation of
COMSAT Capital II", "United States Taxation -- Income from Convertible Preferred
Securities" and  "United  States Taxation  --  Potential Extension  of  Interest
Payment Period".

                                       11
<PAGE>
                               COMSAT CAPITAL II

    COMSAT  Capital  II is  a  limited partnership  which  was formed  under the
Delaware Revised  Uniform Limited  Partnership Act  (the "Partnership  Act")  by
filing a certificate of limited partnership with the Delaware Secretary of State
on  May  22, 1995.  The initial  partners in  COMSAT Capital  II are  COMSAT, as
general partner, and COMSAT SPV, Inc., a Delaware corporation and a wholly owned
subsidiary of COMSAT ("COMSAT  SPV"), as limited partner.  Upon the issuance  of
the Convertible Preferred Securities, which securities represent limited partner
interests in COMSAT Capital II, COMSAT SPV will remain as a limited partner, but
will  have no interest in  the profits and dividends or  in the assets of COMSAT
Capital II. The General Partner will contribute capital in an amount equal to at
least 3% of  the total capital  contributions to COMSAT  Capital II. COMSAT  and
COMSAT  SPV entered  into a  limited partnership agreement  dated as  of May 22,
1995. Such limited  partnership agreement will  be amended and  restated in  its
entirety  (as  so amended  and  restated, the  "Limited  Partnership Agreement")
substantially in the form filed as  an exhibit to the Registration Statement  of
which this Prospectus forms a part.

    COMSAT  Capital II is managed by the General Partner and exists for the sole
purpose of  issuing  the  Convertible Preferred  Securities  and  investing  the
proceeds  thereof in the Convertible Junior Subordinated Debentures. The payment
by COMSAT Capital II of dividends due on the Convertible Preferred Securities is
solely dependent  on  its  receipt  of interest  payments  from  COMSAT  on  the
Convertible  Junior Subordinated  Debentures. The rights  of the  holders of the
Convertible  Preferred  Securities,   including  economic   rights,  rights   to
information  and  voting  rights,  are  set  forth  in  the  Limited Partnership
Agreement and the Partnership Act. See "Description of the Convertible Preferred
Securities". COMSAT Capital  II has  a term  of approximately  99 years,  unless
earlier  dissolved.  COMSAT  Capital  II's registered  office  in  the  State of
Delaware is c/o The  Corporation Trust Company,  Corporation Trust Center,  1209
Orange  Street, Wilmington, New Castle  County, Delaware 19801, telephone: (302)
658-7581. All of COMSAT Capital II's  business and affairs will be conducted  by
COMSAT,  as the sole general partner. The  principal place of business of COMSAT
Capital II  is c/o  COMSAT Corporation,  6560 Rock  Spring Drive,  Bethesda,  MD
20817, telephone number (301) 214-3000.

                               COMSAT CORPORATION

GENERAL

    COMSAT is a global provider of communications and entertainment services and
products   primarily   operating  in   four  business   segments:  International
Communications, Mobile Communications, Entertainment and Technology Services.

    International  Communications  consists  of  COMSAT  World  Systems,   which
provides  satellite communications  services using  the satellite  system of the
International Telecommunications Satellite Organization ("INTELSAT"), and COMSAT
International  Ventures,  which  operates  and  invests  in   telecommunications
ventures  internationally.  Mobile  Communications  consists  of  COMSAT  Mobile
Communications, which  provides  satellite  communications  services  using  the
satellite   system   of   the   International   Mobile   Satellite  Organization
("Inmarsat").  Entertainment  consists  of  COMSAT  Entertainment  Group,  Inc.,
comprising  COMSAT  Video  Enterprises,  Inc.  and  COMSAT's  majority ownership
interest in On Command Video  Corporation, which provide entertainment  services
to  the hospitality  industry throughout  the United  States and  domestic video
distribution services to a television  network; the Denver Nuggets, a  franchise
of  the  National Basketball  Association;  and Beacon  Communications  Corp., a
producer of  theatrical films  and television  programming. Technology  Services
consists  of  COMSAT  RSI,  Inc., which  designs,  manufactures,  and integrates
satellite earth  stations,  advanced  antennas and  other  turnkey  systems  for
telecommunications,  radar, air traffic control  and military uses, and provides
turnkey  voice,  video  and  data  communications  networks  and  products,  and
communication  and  information  services  worldwide,  and  COMSAT Laboratories,
COMSAT's center for applied research and technology development.

                                       12
<PAGE>
    For the  year  ended December  31,  1994, the  International  Communications
segment  had revenues of $271  million and operating income  of $89 million; the
Mobile Communications segment had revenues of $194 million and operating  income
of  $48  million; the  Entertainment segment  had revenues  of $157  million and
operating income  of  $11  million;  and the  Technology  Services  segment  had
revenues of $219 million and operating income of $15 million.

    COMSAT  was  incorporated  in  1963  under  District  of  Columbia  law,  as
authorized by the Communications  Satellite Act of  1962 (the "Satellite  Act").
Effective  June 1, 1993, COMSAT changed  its corporate name from "Communications
Satellite Corporation"  to "COMSAT  Corporation".  COMSAT is  not an  agency  or
establishment of the U.S. Government. The U.S. Government has not invested funds
in  COMSAT, guaranteed  funds invested  in COMSAT  or guaranteed  the payment of
dividends by COMSAT.

    Although COMSAT is a non-governmental publicly held corporation whose common
stock is  traded on  the NYSE,  the  Satellite Act  governs certain  aspects  of
COMSAT's  structure, ownership and  operations, including: three  of COMSAT's 15
directors are appointed by  the President of the  United States with the  advice
and consent of the United States Senate; COMSAT's issuances of capital stock and
borrowings  of money must be authorized by the Federal Communications Commission
(the "FCC");  there are  limitations on  the classes  of persons  that may  hold
shares  of COMSAT's capital stock and on the  number of shares a person or class
of persons may hold; and, on matters  that may affect the national interest  and
foreign  policy of the  United States, COMSAT's  representatives to INTELSAT and
Inmarsat receive instructions  from the U.S.  Government. Congress has  reserved
the  right to amend the Satellite Act,  and amendments, if any, could materially
affect COMSAT.  See "Risk  Factors --  Restrictions on  Ownership, Transfer  and
Voting of COMSAT Common Stock" and "Description of COMSAT Capital Stock".

    Under    the   Satellite   Act,   the   International   Maritime   Satellite
Telecommunications Act of 1978 and the  Communications Act of 1934, as  amended,
COMSAT  is subject  to regulation by  the FCC  with respect to  its COMSAT World
Systems and  COMSAT Mobile  Communications services  and the  rates charged  for
those  services. FCC decisions and policies have had and will continue to have a
significant impact on COMSAT.

    The principal  place  of business  of  COMSAT  is 6560  Rock  Spring  Drive,
Bethesda, MD 20817, telephone number (301) 214-3000.

RECENT DEVELOPMENTS

    On  May 25, 1995, COMSAT Entertainment Group, Inc. announced an agreement to
buy the Quebec  Nordiques NHL  franchise for approximately  $75 million.  COMSAT
plans  to transfer  the team  to Denver,  Colorado in  time for  the 1995-96 NHL
season. The transaction and  transfer fees, if any,  are subject to approval  by
the NHL Board of Governors.

                                       13
<PAGE>
                                USE OF PROCEEDS

    The  proceeds from the sale of  the Convertible Preferred Securities will be
invested in the  Convertible Junior Subordinated  Debentures issued pursuant  to
the  Indenture described herein. In addition,  concurrently with the sale of the
Convertible Preferred  Securities, COMSAT  Capital I,  L.P.  may sell  its     %
Cumulative Monthly Income Preferred Securities (the "Preferred Securities"), the
proceeds  from  which would  be invested  in  COMSAT's    %  Junior Subordinated
Deferrable Interest  Debentures  (the  "Junior  Subordinated  Debentures").  The
aggregate proceeds from the sale of the Convertible Preferred Securities and the
Preferred  Securities will  not exceed  $200 million.  Ultimately, such proceeds
will be used by COMSAT to reduce outstanding commercial paper (at May 30,  1995,
totaling   approximately  $115   million,  at   an  average   interest  cost  of
approximately 6%) and approximately $75 million of indebtedness that COMSAT  may
incur  to fund the  acquisition of the  Quebec Nordiques NHL  franchise, and for
general corporate purposes. See "COMSAT Corporation -- Recent Developments".

                                       14
<PAGE>
                            CAPITALIZATION OF COMSAT

    The following table sets forth  the consolidated short-term obligations  and
capitalization  of COMSAT as of  March 31, 1995, and  as adjusted to reflect the
application of  the estimated  net proceeds  from the  sale of  the  Convertible
Preferred  Securities (assuming  the Underwriters' over-allotment  option is not
exercised) and the Preferred Securities. See "Use of Proceeds".

<TABLE>
<CAPTION>
                                                                                       MARCH 31, 1995
                                                                                   ----------------------
                                                                                    ACTUAL    AS ADJUSTED
                                                                                   ---------  -----------
                                                                                       (IN MILLIONS)
<S>                                                                                <C>        <C>
Commercial paper and current maturities of long-term obligations.................  $     149   $
                                                                                   ---------  -----------
                                                                                   ---------  -----------
Long-term debt...................................................................  $     569   $
                                                                                   ---------  -----------
Company-obligated mandatorily redeemable preferred securities issued by
 subsidiary......................................................................          0
                                                                                   ---------  -----------
Stockholders' equity:
  Common stock...................................................................        315
  Preferred stock................................................................          0
  Retained earnings..............................................................        538
  Treasury stock (at cost).......................................................        (12)
  Other..........................................................................         (3)
                                                                                   ---------  -----------
    Total stockholders' equity...................................................        838
                                                                                   ---------  -----------
    Total capitalization (excluding short-term obligations)......................  $   1,407   $
                                                                                   ---------  -----------
                                                                                   ---------  -----------
</TABLE>

                  RATIO OF EARNINGS TO FIXED CHARGES OF COMSAT

<TABLE>
<CAPTION>
                                                    QUARTER ENDED
                                                      MARCH 31,            YEAR ENDED DECEMBER 31,
                                                    -------------   -------------------------------------
                                                    1995    1994    1994    1993    1992    1991    1990(2)
                                                    -----   -----   -----   -----   -----   -----   -----
<S>                                                 <C>     <C>     <C>     <C>     <C>     <C>     <C>
Ratio of Earnings to Fixed Charges (1):...........   2.4     3.4     3.4     3.7     2.6     3.1      --
<FN>
- - --------------
(1)  For purposes of calculating this  ratio, fixed charges consist of  interest
     expense   including  capitalized  interest,  the  interest  expense  of  an
     unconsolidated majority-owned investment  in 1990,  1991 and  1992, and  an
     estimate  of the  interest factor  of rental  expense. Earnings  consist of
     pretax income (loss) from continuing  operations before fixed charges,  the
     losses   and  undistributed   earnings  of   equity  investments   and  the
     amortization of capitalized interest. During the periods presented,  COMSAT
     did  not have any  preferred stock issued  or outstanding. Accordingly, the
     ratio of earnings to combined  fixed charges and preferred stock  dividends
     is not presented.

(2)  1990  earnings were  inadequate to cover  fixed charges, as  such terms are
     defined in Item  503(d) of Regulation  S-K, with a  coverage deficiency  of
     $23,726,000.  However,  1990  earnings include  a  $97,576,000 nonrecurring
     charge related to  the restructuring  of the  video entertainment  business
     unit.
</TABLE>

                                       15
<PAGE>
               MARKET PRICES OF COMSAT COMMON STOCK AND DIVIDENDS

    The COMSAT Common Stock is traded on the NYSE and on the Chicago and Pacific
Stock   Exchanges  under  the  symbol  "CQ".  At  March  31,  1995,  there  were
approximately 36,000 holders  of record  of COMSAT Common  Stock and  47,143,071
shares  outstanding. The following  table sets forth,  for the calendar quarters
indicated, the high  and low sale  prices, as adjusted  for a two-for-one  stock
split which occurred in June 1993, for COMSAT Common Stock on the NYSE Composite
Tape,  and the  respective cash  dividends paid on  each share  of COMSAT Common
Stock:

<TABLE>
<CAPTION>
                                                         HIGH        LOW     DIVIDEND
                                                        -------    -------   ---------
<S>                                                     <C>        <C>       <C>
CALENDAR YEAR 1993:
  First Quarter........................................  27 7/8     23 3/4       .185
  Second Quarter.......................................  31 5/8     27 1/4       .185
  Third Quarter........................................  31 7/8     26 3/4       .185
  Fourth Quarter.......................................  35 1/4     27 1/2       .185
CALENDAR YEAR 1994:
  First Quarter........................................  30         24 7/8       .185
  Second Quarter.......................................  26 1/2     20 1/2       .185
  Third Quarter........................................  26 1/2     23           .195
  Fourth Quarter.......................................  25 5/8     17 1/2       .195
CALENDAR YEAR 1995:
  First Quarter........................................  21 5/8     17 5/8       .195
  Second Quarter (through         , 1995)..............
</TABLE>

    The closing price of the COMSAT Common  Stock on the NYSE Composite Tape  on
May 31, 1995 was $19 1/2.

    COMSAT  has paid cash dividends on its outstanding common stock in each year
since 1970. COMSAT currently pays cash dividends quarterly at an annual rate  of
$0.78  per share. Future  payment of dividends  on the COMSAT  Common Stock will
depend on earnings, financial condition, capital requirements and other relevant
factors.

                                       16
<PAGE>
              DESCRIPTION OF THE CONVERTIBLE PREFERRED SECURITIES

    THE FOLLOWING  SUMMARY  OF CERTAIN  MATERIAL  TERMS AND  PROVISIONS  OF  THE
CONVERTIBLE  PREFERRED SECURITIES DOES NOT PURPORT TO BE COMPLETE AND IS SUBJECT
TO, AND  QUALIFIED IN  ITS ENTIRETY  BY REFERENCE  TO, THE  LIMITED  PARTNERSHIP
AGREEMENT,  A COPY OF WHICH IS FILED AS AN EXHIBIT TO THE REGISTRATION STATEMENT
OF WHICH THIS  PROSPECTUS IS  A PART.  CAPITALIZED TERMS  NOT OTHERWISE  DEFINED
HEREIN HAVE THE MEANINGS ASSIGNED TO THEM IN THE LIMITED PARTNERSHIP AGREEMENT.

GENERAL

    All  of  the partnership  interests  in COMSAT  Capital  II, other  than the
Convertible  Preferred  Securities  offered   hereby,  are  owned  directly   or
indirectly  by COMSAT. The Limited  Partnership Agreement authorizes and creates
the Convertible Preferred Securities, which represent limited partner  interests
in  COMSAT  Capital  II.  The  limited  partner  interests  represented  by  the
Convertible  Preferred  Securities  will  have  a  preference  with  respect  to
dividends and amounts payable on liquidation over the General Partner's interest
in  COMSAT Capital  II. The  Limited Partnership  Agreement does  not permit the
issuance of any other limited  partnership interests or preferred securities  of
COMSAT Capital II, or the incurrence of any indebtedness by COMSAT Capital II.

DIVIDENDS

    The  dividends payable on each Convertible  Preferred Security will be fixed
at a rate  per annum of     % of the  stated liquidation preference  of $50  per
Convertible  Preferred Security. Dividends in arrears will bear interest thereon
at the rate  per annum  of    %  thereof. The  term "dividends"  as used  herein
includes  any  such  interest payable  unless  otherwise stated.  The  amount of
dividends payable for any period will be computed on the basis of a 360-day year
of twelve 30-day months.

    Dividends on the Convertible Preferred  Securities will be cumulative,  will
accrue from the date of initial issuance and will be payable monthly in arrears,
on  the last day of each calendar month of each year, commencing         , 1995,
when, as and  if available and  determined to be  so payable by  COMSAT, as  the
General Partner, except as otherwise described below. COMSAT has the right under
the  Indenture to extend  the interest payment  period from time  to time on the
Convertible  Junior  Subordinated  Debentures  to  a  period  not  exceeding  60
consecutive  months, and, as a consequence, monthly dividends on the Convertible
Preferred Securities would be deferred by COMSAT Capital II (but would  continue
to  accrue with interest)  during any such extended  interest payment period. In
the event  that COMSAT  exercises this  right,  COMSAT may  not declare  or  pay
dividends on, or redeem, purchase or acquire, any of its capital stock. Prior to
the  termination of  any such  extension period,  COMSAT may  further extend the
interest payment period, provided that  such extension period together with  all
such  previous  and further  extensions thereof  may  not exceed  60 consecutive
months. Upon the termination of any  extension period COMSAT is required to  pay
all  amounts then due and, upon such  payment, COMSAT may select a new extension
period, subject  to the  above requirements.  In no  event shall  any  extension
period  extend  beyond  the  maturity  of  the  Convertible  Junior Subordinated
Debentures. See "Description of  the Convertible Junior Subordinated  Debentures
- - -- Interest" and "-- Option to Extend Interest Payment Period".

    Dividends  on the Convertible Preferred  Securities must be declared monthly
and paid on the dates payable to the extent that COMSAT Capital II has (i) funds
legally available  for the  payment of  such  dividends and  (ii) cash  on  hand
sufficient  to permit such payments. It  is anticipated that COMSAT Capital II's
earnings available for distribution to the holders of the Convertible  Preferred
Securities will be limited to payments under the Convertible Junior Subordinated
Debentures in which COMSAT Capital II will invest the proceeds from the issuance
and  sale  of  the Convertible  Preferred  Securities. See  "Description  of the
Convertible Junior Subordinated  Debentures". The payment  of dividends, to  the
extent declared by COMSAT Capital II out of moneys held by COMSAT Capital II and
legally  available  therefor,  is  guaranteed  by  COMSAT  as  set  forth  under
"Description of the Guarantee".

                                       17
<PAGE>
    Dividends on the  Convertible Preferred  Securities will be  payable to  the
holders  thereof as they appear on the books and records of COMSAT Capital II on
the relevant record  dates, which will  be one Business  Day (as defined  below)
prior  to  the  relevant  payment  dates. Subject  to  any  applicable  laws and
regulations and the provisions of  the Limited Partnership Agreement, each  such
payment  will  be  made  as described  under  "Book-Entry-Only  Issuance  -- The
Depository  Trust  Company"  below.  In  the  event  the  Convertible  Preferred
Securities  shall not  continue to remain  in book-entry-only  form, the General
Partner shall have the right to select relevant record dates which shall be more
than one Business Day prior to the relevant payment dates. In the event that any
date on which dividends are payable  on the Convertible Preferred Securities  is
not  a Business Day, then  payment of the dividend payable  on such date will be
made on  the next  succeeding  day which  is a  Business  Day (and  without  any
interest  or other payment  in respect of  any such delay)  except that, if such
Business Day is in the next succeeding calendar year, such payment shall be made
on the immediately preceding Business Day, in each case with the same force  and
effect as if made on such date. A "Business Day" shall mean any day other than a
day  on which  banking institutions in  The City  of New York  are authorized or
required by law to close.

CONVERSION RIGHTS

    GENERAL.  Convertible Preferred Securities will be convertible at any  time,
at  the option  of the holder  thereof and  in the manner  described below, into
shares of COMSAT Common Stock at  an initial conversion rate of       shares  of
COMSAT  Common Stock  for each Convertible  Preferred Security  (equivalent to a
conversion price  of          per  share of  COMSAT  Common Stock),  subject  to
adjustment  as described under "-- Conversion Price Adjustments" below. A holder
of a Convertible  Preferred Security  wishing to exercise  its conversion  right
shall   surrender  such   Convertible  Preferred  Security,   together  with  an
irrevocable conversion notice, to the Conversion Agent which shall, on behalf of
such holder, exchange such Convertible Preferred  Security for a portion of  the
Convertible   Junior  Subordinated  Debentures   and  immediately  convert  such
Convertible Junior Subordinated Debentures into COMSAT Common Stock. Holders may
obtain copies of the required form of the conversion notice from the  Conversion
Agent.

    Holders  of Convertible Preferred  Securities at the close  of business on a
dividend record date will  be entitled to receive  the dividend payable on  such
Convertible  Preferred  Securities on  the  corresponding dividend  payment date
notwithstanding  the  conversion  of   such  Convertible  Preferred   Securities
following  such dividend  record date but  prior to such  dividend payment date.
Except as provided in the immediately preceding sentence, neither COMSAT Capital
II nor COMSAT  will make,  or be  required to  make, any  payment, allowance  or
adjustment  for accumulated and unpaid dividends,  whether or not in arrears, on
converted Convertible  Preferred  Securities. COMSAT  will  make no  payment  or
allowance  for dividends on the  shares of COMSAT Common  Stock issued upon such
conversion, except to  the extent that  such shares of  COMSAT Common Stock  are
held  of record on the record date  for any such dividends. Each conversion will
be deemed to have been  effected immediately prior to  the close of business  on
the  day on which the  related conversion notice was  received by COMSAT Capital
II.

    No fractional shares of COMSAT  Common Stock will be  issued as a result  of
conversion,  but in lieu thereof such fractional interest will be paid by COMSAT
in cash. For  a discussion of  certain restrictions on  ownership, transfer  and
voting  of COMSAT Common Stock, see  "Risk Factors -- Restrictions on Ownership,
Transfer and Voting of COMSAT Common Stock".

    CONVERSION PRICE  ADJUSTMENTS --  GENERAL.   The  conversion price  will  be
subject  to adjustment in certain events including, without duplication: (i) the
payment of dividends (and other distributions) payable in COMSAT Common Stock on
any class of capital stock of COMSAT; (ii) the issuance to all holders of COMSAT
Common Stock of rights or warrants entitling holders of such rights or  warrants
to  subscribe for or purchase COMSAT Common  Stock at less than the then Current
Market Price (as defined herein); (iii) subdivisions and combinations of  COMSAT
Common  Stock; (iv)  the payment of  dividends (and other  distributions) to all
holders of COMSAT Common Stock consisting of evidences

                                       18
<PAGE>
of indebtedness  of  COMSAT,  securities  or  capital  stock,  cash,  or  assets
(including  securities,  but excluding  those  rights, warrants,  dividends, and
distributions  referred  to  in   clauses  (i)  and   (ii)  and  dividends   and
distributions paid exclusively in cash); (v) the payment of dividends (and other
distributions)  on COMSAT Common  Stock paid exclusively  in cash, excluding (A)
cash dividends  that do  not exceed  the  per share  amount of  the  immediately
preceding  regular  cash dividend  (as  adjusted to  reflect  any of  the events
referred to in clauses (i) through (vi) of this sentence), or (B) cash dividends
if the annualized per share  amount thereof does not  exceed 15% of the  Current
Market Price of COMSAT Common Stock on the trading day immediately preceding the
date  of declaration  of such  dividend; and (vi)  payment to  holders of COMSAT
Common Stock in respect  of a tender  or exchange offer  (other than an  odd-lot
offer)  by COMSAT or any subsidiary of COMSAT for COMSAT Common Stock at a price
in excess of  110% of the  Current Market Price  of COMSAT Common  Stock on  the
trading  day next  succeeding the  last date  tenders or  exchanges may  be made
pursuant to such tender or exchange offer.

    COMSAT from time to time may reduce the conversion price of the  Convertible
Junior Subordinated Debentures (and thus the conversion price of the Convertible
Preferred  Securities) by  any amount  selected by COMSAT  for any  period of at
least 20 days, in which case COMSAT shall give at least 15 days' notice of  such
reduction.  COMSAT may,  at its option,  make such reductions  in the conversion
price, in addition to those  set forth above, as  the COMSAT Board of  Directors
deems  advisable to avoid or diminish any income tax to holders of COMSAT Common
Stock resulting from any dividend or distribution of stock (or rights to acquire
stock) or from any event  treated as such for  income tax purposes. See  "United
States Taxation -- Adjustment of Conversion Price".

    No  adjustment of the conversion price will be made upon the issuance of any
shares of COMSAT Common Stock pursuant  to any present or future plan  providing
for  the reinvestment of  dividends or interest payable  on securities of COMSAT
and the investment  of additional optional  amounts in shares  of COMSAT  Common
Stock  under any such plan, or the issuance of any shares of COMSAT Common Stock
or options or rights to purchase such  shares pursuant to any present or  future
employee,  director or consultant benefit plan  or program of COMSAT or pursuant
to any  option,  warrant, right,  or  exercisable, exchangeable  or  convertible
security  outstanding as of  the date the  Convertible Preferred Securities were
first issued. There shall also be no adjustment of the conversion price in  case
of  the issuance of any  COMSAT Common Stock (or  securities convertible into or
exchangeable for COMSAT Common Stock),  except as specifically described  above.
If  any action would require adjustment of the conversion price pursuant to more
than one of the anti-dilution provisions, only one adjustment shall be made  and
such  adjustment shall be the amount of adjustment that has the highest absolute
value to holders of the Convertible  Preferred Securities. No adjustment in  the
conversion  price  will  be required  unless  such adjustment  would  require an
increase or decrease of at least 1% of the conversion price, but any  adjustment
that  would otherwise be required to be  made shall be carried forward and taken
into account in any subsequent adjustment.

    The term "Current Market Price" of COMSAT Common Stock for any day means the
last reported sale price, regular way, on  such day, or, if no sale takes  place
on  such day, the average  of the reported closing bid  and asked prices on such
day, regular way, in either case as reported on the NYSE Composite Tape, or,  if
the COMSAT Common Stock is not listed or admitted to trading on the NYSE, on the
principal  national  securities exchange  on which  the  COMSAT Common  Stock is
listed or  admitted to  trading,  if the  COMSAT Common  Stock  is listed  on  a
national  securities exchange,  or the  National Market  System of  the National
Association of Securities Dealers, Inc., or,  if the COMSAT Common Stock is  not
quoted  or  admitted  to trading  on  such  quotation system,  on  the principal
quotation system on which the COMSAT Common  Stock may be listed or admitted  to
trading  or quoted, or,  if not listed or  admitted to trading  or quoted on any
national securities exchange or quotation system, the average of the closing bid
and asked prices of  the COMSAT Common Stock  in the over-the-counter market  on
the  day in question as reported  by the National Quotation Bureau Incorporated,
or a similar generally  accepted reporting service, or,  if not so available  in
such manner,

                                       19
<PAGE>
as  furnished by any NYSE member firm selected from time to time by the Board of
Directors of COMSAT for that purpose or, if not so available in such manner,  as
otherwise determined in good faith by such Board of Directors.

    CONVERSION  PRICE ADJUSTMENTS -- MERGER, CONSOLIDATION  OR SALE OF ASSETS OF
COMSAT.  In  the event that  COMSAT is  a party to  any transaction  (including,
without limitation, a merger, consolidation, sale of all or substantially all of
the  assets  of COMSAT,  recapitalization or  reclassification of  COMSAT Common
Stock or any compulsory share exchange (each of the foregoing being referred  to
as a "Transaction")), in each case, as a result of which shares of COMSAT Common
Stock shall be converted into the right (i) in the case of any Transaction other
than  a  Transaction involving  a Common  Stock  Fundamental Change  (as defined
herein), to  receive  securities,  cash  or  other  property,  each  Convertible
Preferred  Security shall thereafter be convertible  into the kind and amount of
securities, cash and  other property  receivable upon the  consummation of  such
Transaction  by a holder  of that number  of shares of  COMSAT Common Stock into
which a Convertible Preferred Security was convertible immediately prior to such
Transaction, or  (ii) in  the case  of a  Transaction involving  a Common  Stock
Fundamental  Change, to receive common stock of  the kind received by holders of
COMSAT Common Stock  (but in  each case after  giving effect  to any  adjustment
discussed below relating to a Fundamental Change if such Transaction constitutes
a Fundamental Change). The holders of Convertible Preferred Securities will have
no voting rights with respect to any Transaction described in this section.

    If  any Fundamental Change  (as defined herein)  occurs, then the conversion
price in effect will  be adjusted immediately after  such Fundamental Change  as
described below. In addition, in the event of a Common Stock Fundamental Change,
each  Convertible  Preferred Security  shall be  convertible solely  into common
stock of the kind received by holders of COMSAT Common Stock as a result of such
Common Stock Fundamental Change.

    The conversion price in the case of any Transaction involving a  Fundamental
Change will be adjusted immediately after such Fundamental Change:

        (i)  in the case of a  Non-Stock Fundamental Change (as defined herein),
    the conversion price of the Convertible Preferred Securities will  thereupon
    become  the lower of (A) the conversion price in effect immediately prior to
    such Non-Stock  Fundamental Change,  but after  giving effect  to any  other
    prior adjustments, and (B) the result obtained by multiplying the greater of
    the  Applicable Price (as  defined herein) or  the then applicable Reference
    Market Price (as defined herein) by  a fraction of which the numerator  will
    be  $50  and the  denominator will  be an  amount per  Convertible Preferred
    Security determined by  the General  Partner in its  sole discretion,  after
    consultation  with an investment  banking firm, to be  the equivalent of the
    hypothetical redemption  price  that  would  have  been  applicable  if  the
    Convertible Preferred Securities had been redeemable during such period; and

        (ii)  in the case  of a Common Stock  Fundamental Change, the conversion
    price of the Convertible Preferred Securities in effect immediately prior to
    such Common Stock Fundamental Change, but  after giving effect to any  other
    prior adjustments, will thereupon be adjusted by multiplying such conversion
    price by a fraction of which the numerator will be the Purchaser Stock Price
    (as  defined  herein)  and the  denominator  will be  the  Applicable Price;
    provided, however, that in the event of a Common Stock Fundamental Change in
    which (A) 100% of  the value of  the consideration received  by a holder  of
    COMSAT  Common Stock  is common stock  of the successor,  acquiror, or other
    third party (and cash, if any, is  paid only with respect to any  fractional
    interests  in such common stock resulting from such Common Stock Fundamental
    Change) and (B) all of the COMSAT Common Stock will have been exchanged for,
    converted into,  or acquired  for common  stock (and  cash with  respect  to
    fractional  interests) of the successor, acquiror, or other third party, the
    conversion  price  of  the   Convertible  Preferred  Securities  in   effect
    immediately  prior to such Common Stock Fundamental Change will thereupon be
    adjusted by multiplying  such conversion price  by a fraction  of which  the
    numerator will be one and the

                                       20
<PAGE>
    denominator  will be the number of shares  of common stock of the successor,
    acquiror, or other third party received by  a holder of one share of  COMSAT
    Common Stock as a result of such Common Stock Fundamental Change.

    In  the  absence of  the Fundamental  Change  provisions, in  the case  of a
Transaction each Convertible  Preferred Security would  become convertible  into
the securities, cash, or property receivable by a holder of the number of shares
of  COMSAT  Common  Stock into  which  such Convertible  Preferred  Security was
convertible immediately prior to such Transaction.  Thus, in the absence of  the
Fundamental  Change  provisions,  a Transaction  could  substantially  lessen or
eliminate the value of the conversion privilege associated with the  Convertible
Preferred  Securities. For  example, if COMSAT  were acquired in  a cash merger,
each Convertible Preferred  Security would become  convertible solely into  cash
and  would  no longer  be  convertible into  securities  whose value  would vary
depending on the future prospects of COMSAT and other factors.

    The foregoing  conversion price  adjustments are  designed, in  "Fundamental
Change"  transactions where all or substantially  all the COMSAT Common Stock is
converted into securities, cash, or property and not more than 50% of the  value
received  by the  holders of  COMSAT Common  Stock consists  of stock  listed or
admitted for listing  subject to  notice of  issuance on  a national  securities
exchange  or quoted on the National Market System of the National Association of
Securities Dealers, Inc. (a "Non-Stock Fundamental Change," as defined  herein),
to  increase  the  securities, cash,  or  property into  which  each Convertible
Preferred Security is convertible.

    In a  Non-Stock  Fundamental  Change transaction  where  the  initial  value
received  per  share  of  COMSAT  Common Stock  (measured  as  described  in the
definition of  Applicable  Price  below)  is  lower  than  the  then  applicable
conversion  price of a Convertible Preferred  Security but greater than or equal
to the  "Reference Market  Price" (initially  $   but subject  to adjustment  in
certain  events as  described below), the  conversion price will  be adjusted as
described above with the effect that each Convertible Preferred Security will be
convertible into securities, cash or property  of the same type received by  the
holders  of  COMSAT  Common Stock  in  such  transaction but  in  an  amount per
Convertible Preferred  Security determined  by COMSAT  in its  sole  discretion,
after  consultation with an investment banking firm, to be the equivalent of the
hypothetical redemption price that would have been applicable if the Convertible
Preferred Securities had been redeemable during such period.

    In a  Non-Stock  Fundamental  Change transaction  where  the  initial  value
received  per  share  of  COMSAT  Common Stock  (measured  as  described  in the
definition of  Applicable  Price  below)  is  lower  than  both  the  Applicable
Conversion  Price of a  Convertible Preferred Security  and the Reference Market
Price, the conversion price will be  adjusted as described above but  calculated
as though such initial value had been the Reference Market Price.

    In  a Fundamental Change  transaction where all or  substantially all of the
COMSAT Common Stock  is converted into  securities, cash, or  property and  more
than 50% of the value received by the holders of COMSAT Common Stock consists of
listed   or  National  Market  System  traded  common  stock  (a  "Common  Stock
Fundamental Change," as defined herein), the foregoing adjustments are  designed
to provide in effect that (a) where COMSAT Common Stock is converted partly into
such  common stock  and partly  into other  securities, cash,  or property, each
Convertible Preferred  Security will  be  convertible solely  into a  number  of
shares  of such common stock determined so that the initial value of such shares
(measured as  described in  the  definition of  "Purchaser Stock  Price"  below)
equals  the  value  of  the  shares  of  COMSAT  Common  Stock  into  which such
Convertible  Preferred   Security  was   convertible  immediately   before   the
transaction  (measured  as  aforesaid)  and (b)  where  COMSAT  Common  Stock is
converted solely into  such common  stock, each  Convertible Preferred  Security
will  be  convertible  into the  same  number  of shares  of  such  common stock
receivable by a holder of the number of shares of COMSAT Common Stock into which
such Convertible  Preferred Security  was  convertible immediately  before  such
transaction.

                                       21
<PAGE>
    The term "Applicable Price" means (i) in the case of a Non-Stock Fundamental
Change  in which the  holder of the  COMSAT Common Stock  receive only cash, the
amount of cash received by  the holder of one share  of COMSAT Common Stock  and
(ii)  in the event of any other Non-Stock Fundamental Change or any Common Stock
Fundamental Change, the average  of the Closing Prices  (as defined herein)  for
the  COMSAT Common Stock during the ten  trading days prior to and including the
record date for the determination of the holders of COMSAT Common Stock entitled
to receive such  securities, cash,  or other  property in  connection with  such
Non-Stock  Fundamental Change or Common Stock Fundamental Change or, if there is
no such record date, the date upon which the holders of the COMSAT Common  Stock
shall  have the right to receive such  securities, cash, or other property (such
record date or distribution date being hereinafter referred as the  "Entitlement
Date"),  in  each case  as adjusted  in  good faith  by COMSAT  to appropriately
reflect any of the events referred to  in clauses (i) through (vi) of the  first
paragraph under "-- Conversion Price Adjustments -- General".

    The  term "Closing Price" means on any  day the reported last sales price on
such day or in case no sale takes place on such day, the average of the reported
closing bid and asked prices in each case on the NYSE Composite Tape or, if  the
stock  is not listed or  admitted to trading on  such exchange, on the principal
national securities  exchange on  which  such stock  is  listed or  admitted  to
trading  or if  not listed  or admitted  to trading  on any  national securities
exchange, the average of the  closing bid and asked  prices as furnished by  any
NYSE member firm, selected by the General Partner for that purpose.

    The  term "Common Stock Fundamental Change"  means any Fundamental Change in
which more than 50% of  the value (as determined in  good faith by the Board  of
Directors  of COMSAT) of the consideration  received by holders of COMSAT Common
Stock consists of common stock that for each of the ten consecutive trading days
prior to the  Entitlement Date  has been admitted  for listing  or admitted  for
listing  subject  to notice  of issuance  on a  national securities  exchange or
quoted on the National Market System  of the National Association of  Securities
Dealers,  Inc.;  provided, however,  that a  Fundamental Change  shall not  be a
Common Stock  Fundamental Change  unless either  (i) COMSAT  continues to  exist
after  the occurrence of such Fundamental Change and the outstanding Convertible
Preferred Securities  continue to  exist  as outstanding  Convertible  Preferred
Securities or (ii) not later than the occurrence of such Fundamental Change, the
outstanding Convertible Preferred Securities are converted into or exchanged for
shares of convertible preferred stock of an entity succeeding to the business of
COMSAT, which convertible preferred stock has powers, preferences, and relative,
participating,  optional, or other rights,  and qualifications, limitations, and
restrictions, substantially  similar  to  those  of  the  Convertible  Preferred
Securities.

    The  term "Fundamental  Change" means the  occurrence of  any transaction or
event in connection with a  plan pursuant to which  all or substantially all  of
the COMSAT Common Stock shall be exchanged for, converted into, acquired for, or
constitute  solely  the right  to receive  securities,  cash, or  other property
(whether  by   means  of   an  exchange   offer,  liquidation,   tender   offer,
consolidation,   merger,  combination,  reclassification,  recapitalization,  or
otherwise), provided, that, in the case of  a plan involving more than one  such
transaction  or event, for purposes of  adjustment of the conversion price, such
Fundamental Change shall be  deemed to have occurred  when substantially all  of
the  COMSAT Common Stock shall be exchanged for, converted into, or acquired for
or constitute solely the right to  receive securities, cash, or other  property,
but  the adjustment shall be  based upon the highest  weighted average per share
consideration that a holder of COMSAT  Common Stock could have received in  such
transaction  or event as  a result of which  more than 50%  of the COMSAT Common
Stock shall  have  been  exchanged  for, converted  into,  or  acquired  for  or
constitute solely the right to receive securities, cash, or other property.

    The  term "Non-Stock Fundamental Change"  means any Fundamental Change other
than a Common Stock Fundamental Change.

    The term "Purchaser  Stock Price" means,  with respect to  any Common  Stock
Fundamental  Change,  the average  of the  Closing Prices  for the  common stock
received in such Common Stock

                                       22
<PAGE>
Fundamental Change for the ten consecutive  trading days prior to and  including
the  Entitlement  Date, as  adjusted in  good faith  by COMSAT  to appropriately
reflect any of the events referred to  in clauses (i) through (vi) of the  first
paragraph under "-- Conversion Price Adjustments -- General".

    The  term "Reference  Market Price"  shall initially  mean $   (which  is an
amount equal to 66 2/3%  of the reported last sale  price for the COMSAT  Common
Stock  on the NYSE Composite Tape on             , 1995) and in the event of any
adjustment to  the  conversion price  other  than as  a  result of  a  Non-Stock
Fundamental  Change, the Reference  Market Price shall also  be adjusted so that
the ratio of  the Reference Market  Price to the  conversion price after  giving
effect to any such adjustment shall always be the same as the ratio of $  to the
initial conversion price of the Convertible Preferred Securities.

OPTIONAL REDEMPTION

    The  Convertible Preferred Securities are redeemable at the option of COMSAT
Capital II, in whole or in part, from time  to time, on or after               ,
    ,  upon not less  than 30 nor more  than 60 days'  notice, at the Redemption
Price. In the event  that fewer than all  the outstanding Convertible  Preferred
Securities  are to  be so redeemed,  the Convertible Preferred  Securities to be
redeemed will be selected  as described under  "Book-Entry-Only Issuance --  The
Depository  Trust Company"  below. If a  partial redemption would  result in the
delisting of the Convertible  Preferred Securities, COMSAT  Capital II may  only
redeem the Convertible Preferred Securities in whole.

TAX EVENT OR INVESTMENT COMPANY EVENT REDEMPTION OR DISTRIBUTION

    If  a Tax  Event shall  occur and be  continuing, the  General Partner shall
elect to (i) redeem  the Convertible Preferred Securities  in whole (and not  in
part),  upon not less  than 30 nor more  than 60 days'  notice at the Redemption
Price within 90 days following the occurrence of such Tax Event; provided, that,
if at the  time there is  available to  the General Partner  the opportunity  to
eliminate,  within such 90-day period, the  Tax Event by taking some ministerial
action, such as  filing a form  or making  an election, or  pursuing some  other
similar  reasonable measure, which has no adverse effect on COMSAT Capital II or
COMSAT, the General Partner will pursue such measure in lieu of redemption, (ii)
dissolve COMSAT Capital II and cause Convertible Junior Subordinated  Debentures
to  be distributed  to the  holders of  the Convertible  Preferred Securities in
liquidation of  COMSAT Capital  II,  or (iii)  cause the  Convertible  Preferred
Securities  to remain outstanding and pay Additional Interest on the Convertible
Junior Subordinated  Debentures.  See  "Description of  the  Convertible  Junior
Subordinated Debentures -- Additional Interest".

    "Tax Event" means that the General Partner shall have obtained an opinion of
nationally recognized independent tax counsel experienced in such matters to the
effect  that, as  a result  of (a)  any amendment  to, or  change (including any
announced prospective change) in,  the laws (or  any regulations thereunder)  of
the  United States or  any political subdivision or  taxing authority thereof or
therein, (b) any amendment to or  change in an interpretation or application  of
such  laws or regulations by any legislative body, court, governmental agency or
regulatory authority  (including  the  enactment  of  any  legislation  and  the
publication of any judicial decision or regulatory determination on or after the
date  of  this  Prospectus)  or (c)  any  interpretation  or  pronouncement that
provides for a position  with respect to such  laws or regulations that  differs
from  the  generally accepted  position on  the date  of this  Prospectus, which
amendment or change  is effective  or which interpretation  or pronouncement  is
announced  on  or after  the  date of  this Prospectus,  there  is more  than an
insubstantial risk that (i) COMSAT Capital  II is subject to federal income  tax
with  respect  to  interest  received  on  the  Convertible  Junior Subordinated
Debentures, (ii) interest payable to COMSAT Capital II on the Convertible Junior
Subordinated Debentures will not be  deductible for federal income tax  purposes
or  (iii) COMSAT Capital II is subject to more than a DE MINIMIS amount of other
taxes, duties or other governmental charges.

    If an Investment Company  Event shall occur and  be continuing, the  General
Partner shall elect to either (i) redeem the Convertible Preferred Securities in
whole  (and not in part), upon not less than 30 nor more than 60 days' notice at
the  Redemption  Price  within  90   days  following  the  occurrence  of   such

                                       23
<PAGE>
Investment  Company Event; provided, that, if at  the time there is available to
the General Partner the opportunity to eliminate, within such 90-day period, the
Investment Company Act Event by taking some ministerial action, such as filing a
form or making an election, or  pursuing some other similar reasonable  measure,
which  has no adverse effect on COMSAT Capital II or COMSAT, the General Partner
will pursue such measure in lieu of redemption, or (ii) dissolve COMSAT  Capital
II and cause the Convertible Junior Subordinated Debentures to be distributed to
the  holders of  the Convertible Preferred  Securities in  liquidation of COMSAT
Capital II, within 90 days following  the occurrence of such Investment  Company
Event.

    "Investment  Company  Event" means  the  occurrence of  a  change in  law or
regulation or  a written  change  in interpretation  or  application of  law  or
regulation  by any  legislative body,  court, governmental  agency or regulatory
authority (a "Change in 1940 Act Law")  to the effect that COMSAT Capital II  is
or will be considered an "investment company" which is required to be registered
under  the Investment Company  Act of 1940,  as amended (the  "1940 Act"), which
Change in  1940  Act  Law  becomes  effective on  or  after  the  date  of  this
Prospectus;  provided, that no Investment Company  Event shall be deemed to have
occurred if  the  General  Partner  obtains  a  written  opinion  of  nationally
recognized independent counsel experienced in practice under the 1940 Act to the
effect  that  the  General  Partner has  successfully  issued  an  additional or
supplemental irrevocable and unconditional guarantee  (x) of accrued and  unpaid
dividends  (whether or not determined to be paid out of moneys legally available
therefor) on the Convertible Preferred Securities and (y) of the full amount  of
the  Liquidation Distribution  (as defined  below) on  the Convertible Preferred
Securities upon a liquidation of COMSAT Capital II (regardless of the amount  of
assets  of  COMSAT  Capital  II otherwise  available  for  distribution  in such
liquidation) to avoid such Change in 1940 Act Law so that in the opinion of such
counsel, notwithstanding such Change in 1940  Act Law, COMSAT Capital II is  not
required  to be registered as an "investment  company" within the meaning of the
1940 Act.

    After the date fixed for any distribution of Convertible Junior Subordinated
Debentures upon dissolution of COMSAT Capital II, (i) the Convertible  Preferred
Securities will no longer be deemed to be outstanding, (ii) The Depository Trust
Company  (the "Depository" or "DTC") or its nominee, as the record holder of the
Convertible Preferred Securities, will  receive a registered global  certificate
or  certificates representing the Convertible  Junior Subordinated Debentures to
be delivered  upon such  distribution and  (iii) any  certificates  representing
Convertible  Preferred Securities not held by DTC  or its nominee will be deemed
to represent  Convertible  Junior  Subordinated Debentures  having  a  principal
amount  equal  to the  aggregate of  the stated  liquidation preference  of such
Convertible Preferred Securities, with accrued and unpaid interest equal to  the
amount of accrued and unpaid dividends on such Convertible Preferred Securities,
until  such certificates are  presented to COMSAT  or its agent  for transfer or
reissuance.

MANDATORY REDEMPTION

    Upon the  repayment of  the Convertible  Junior Subordinated  Debentures  at
maturity or upon any acceleration, earlier redemption or otherwise, the proceeds
from  such  repayment  will  be  applied  to  redeem  the  Convertible Preferred
Securities, in whole, upon not  less than 30 nor more  than 60 days' notice,  at
the Redemption Price.

REDEMPTION PROCEDURES

    COMSAT  Capital II may not redeem fewer than all the outstanding Convertible
Preferred Securities unless all accrued and  unpaid dividends have been paid  on
all   Convertible  Preferred   Securities  for  all   monthly  dividend  periods
terminating on or prior to the date of redemption.

    If COMSAT Capital II gives a notice of redemption in respect of  Convertible
Preferred  Securities (which notice  will be irrevocable),  then, by 12:00 noon,
New York  time, on  the  redemption date,  COMSAT  Capital II  will  irrevocably
deposit  with DTC  funds sufficient to  pay the applicable  Redemption Price and
will give DTC irrevocable instructions and authority to pay the Redemption Price
to the holders  of the  Convertible Preferred  Securities. See  "Book-Entry-Only
Issuance  -- The Depository  Trust Company". If notice  of redemption shall have
been given and funds are deposited as required,

                                       24
<PAGE>
then upon the date of  such deposit, all rights  of holders of such  Convertible
Preferred  Securities so called  for redemption will cease,  except the right of
the holders of such Convertible  Preferred Securities to receive the  Redemption
Price, but without interest on such Redemption Price. In the event that any date
fixed  for redemption of Convertible Preferred Securities is not a Business Day,
then payment of the Redemption  Price payable on such date  will be made on  the
next  succeeding day which is a Business  Day (and without any interest or other
payment in respect of any such delay),  except that, if such Business Day  falls
in  the  next  calendar year,  such  payment  will be  made  on  the immediately
preceding Business Day.  In the event  that payment of  the Redemption Price  in
respect  of Convertible Preferred  Securities is improperly  withheld or refused
and not paid either by COMSAT Capital II or by COMSAT pursuant to the  Guarantee
described  under "Description of  the Guarantee", dividends  on such Convertible
Preferred Securities will continue to accrue  at the then applicable rate,  from
the  original redemption date to  the date of payment,  in which case the actual
payment date will be  considered the date fixed  for redemption for purposes  of
calculating the Redemption Price.

    Subject  to the foregoing and applicable law (including, without limitation,
United States federal securities  laws), COMSAT or its  subsidiaries may at  any
time and from time to time purchase outstanding Convertible Preferred Securities
by tender, in the open market or by private agreement.

LIQUIDATION DISTRIBUTION UPON DISSOLUTION

    In  the event  of any  voluntary or  involuntary dissolution,  winding-up or
termination of  COMSAT Capital  II,  the holders  of the  Convertible  Preferred
Securities  at the time will be entitled to  receive out of the assets of COMSAT
Capital  II  available  for  distribution  to  partners  after  satisfaction  of
liabilities  of  creditors  as  required  by  the  Partnership  Act,  before any
distribution of assets is made  to the General Partner,  an amount equal to,  in
the  case of holders  of Convertible Preferred Securities,  the aggregate of the
stated liquidation  preference of  $50 per  Convertible Preferred  Security  and
accrued  and unpaid dividends  thereon to the date  of payment (the "Liquidation
Distribution"), unless,  in  connection  with such  dissolution,  winding-up  or
termination,   Convertible  Junior  Subordinated   Debentures  in  an  aggregate
principal amount equal to the Liquidation Distribution have been distributed  on
a pro rata basis to the holders of the Convertible Preferred Securities.

    Pursuant  to the Limited  Partnership Agreement, COMSAT  Capital II shall be
dissolved and its  affairs shall  be wound  up: (i)  on December  31, 2094,  the
expiration  of the term  of COMSAT Capital  II, (ii) upon  the bankruptcy of the
General Partner, (iii) upon the assignment by the General Partner of its  entire
interest  in  COMSAT Capital  II when  the  assignee is  not admitted  to COMSAT
Capital II as  a general partner  of COMSAT  Capital II in  accordance with  the
Limited  Partnership Agreement, or the filing of a certificate of dissolution or
its equivalent with  respect to the  General Partner, or  the revocation of  the
General Partner's charter and the expiration of 90 days after the date of notice
to  the General Partner of revocation without a reinstatement of its charter, or
any other event occurs which causes the General Partner to cease to be a general
partner of COMSAT Capital II under  the Partnership Act, unless the business  of
COMSAT  Capital II is continued in accordance  with the Partnership Act, (iv) in
accordance with the provisions of the Convertible Preferred Securities, (v) upon
the entry of a decree of a judicial dissolution or (vi) upon the written consent
of all partners of COMSAT Capital II.

MERGER, CONSOLIDATION OR AMALGAMATION OF COMSAT CAPITAL II

    COMSAT Capital II may not consolidate, amalgamate, merge with or into, or be
replaced  by,  or  convey,   transfer  or  lease   its  properties  and   assets
substantially  as  an  entirety to  any  corporation  or other  body,  except as
described below. COMSAT Capital  II may, without the  consent of the holders  of
the  Convertible Preferred  Securities, consolidate,  amalgamate, merge  with or
into, or be replaced by, a limited partnership, a limited liability company or a
trust organized as  such under the  laws of any  state of the  United States  of
America or of the District of Columbia; provided, that (i) such successor entity
either  (x) expressly assumes all of the  obligations of COMSAT Capital II under
the Convertible  Preferred Securities  or (y)  substitutes for  the  Convertible
Preferred Securities other securities having substantially the same terms as the
Convertible    Preferred    Securities   (the    "Successor    Securities")   so

                                       25
<PAGE>
long as the  Successor Securities  rank, with  respect to  participation in  the
profits and dividends or in the assets of the successor entity, at least as high
as  the Convertible Preferred  Securities rank with  respect to participation in
the profits and dividends  or in the  assets of COMSAT  Capital II, (ii)  COMSAT
expressly  acknowledges such successor  entity as the  holder of the Convertible
Junior Subordinated Debentures,  (iii) the Convertible  Preferred Securities  or
any  Successor Securities are listed, or any Successor Securities will be listed
upon notification  of issuance,  on any  national securities  exchange or  other
organization on which the Convertible Preferred Securities are then listed, (iv)
such  merger,  consolidation, amalgamation  or  replacement does  not  cause the
Convertible Preferred  Securities (including  any  Successor Securities)  to  be
downgraded  by any  nationally recognized  statistical rating  organization, (v)
such merger,  consolidation,  amalgamation  or replacement  does  not  adversely
affect  the powers, preferences and  other special rights of  the holders of the
Convertible Preferred  Securities (including  any Successor  Securities) in  any
material  respect,  (vi)  such  successor  entity  has  a  purpose substantially
identical to that of COMSAT Capital II, (vii) COMSAT has provided a guarantee to
the holders of the  Successor Securities with respect  to such successor  entity
having  substantially the same terms as the  Guarantee, and (viii) prior to such
merger, consolidation,  amalgamation  or  replacement, COMSAT  has  received  an
opinion  of  nationally  recognized  independent counsel  to  COMSAT  Capital II
experienced in such matters  to the effect that  (x) such successor entity  will
not be treated as an association taxable as a corporation for federal income tax
purposes, (y) following such merger, consolidation, amalgamation or replacement,
neither  COMSAT nor  such successor  entity will be  required to  register as an
investment company  under  the 1940  Act  and (z)  such  merger,  consolidation,
amalgamation  or replacement will not adversely  affect the limited liability of
the holders  of  the Convertible  Preferred  Securities. See  "Risk  Factors  --
Replacement of COMSAT Capital II with a Trust".

VOTING RIGHTS

    Except  as  provided  below  and  under  "Description  of  the  Guarantee --
Amendments and Assignment"  and as  otherwise required  by law  and the  Limited
Partnership  Agreement, the holders of the Convertible Preferred Securities will
have no voting rights.

    If (i) COMSAT Capital II fails to  pay dividends in full on the  Convertible
Preferred  Securities for 18 consecutive monthly dividend periods; (ii) an Event
of Default  (as  defined in  the  Indenture) occurs  and  is continuing  on  the
Convertible Junior Subordinated Debentures; or (iii) COMSAT is in default on any
of  its payment  or other  obligations under  the Guarantee  (as described under
"Description of the Guarantee -- Certain Covenants of COMSAT"), then the holders
of the Convertible Preferred Securities will be entitled by the majority vote of
such holders to appoint and authorize a special representative of COMSAT Capital
II and  the limited  partners  (a "Special  Representative") to  enforce  COMSAT
Capital   II's  creditor  rights  under   the  Convertible  Junior  Subordinated
Debentures, to enforce the  rights of the holders  of the Convertible  Preferred
Securities  under the Guarantee and to enforce  the rights of the holders of the
Convertible  Preferred  Securities  to  receive  dividends  on  the  Convertible
Preferred  Securities. The  Special Representative  shall not  be admitted  as a
general partner in  COMSAT Capital II  or otherwise  be deemed to  be a  general
partner  in  COMSAT  Capital II  and  shall  have no  liability  for  the debts,
obligations or liabilities  of COMSAT  Capital II. For  purposes of  determining
whether COMSAT Capital II has failed to pay dividends in full for 18 consecutive
monthly  dividend  periods,  dividends shall  be  deemed to  remain  in arrears,
notwithstanding any payments in respect thereof, until full cumulative dividends
have been or  contemporaneously are paid  with respect to  all monthly  dividend
periods  terminating on or prior to the  date of payment of such full cumulative
dividends. Not  later  than  30 days  after  such  right to  appoint  a  Special
Representative  arises,  the  General Partner  will  convene a  meeting  for the
purpose of appointing a Special Representative. If the General Partner fails  to
convene  such  meeting  within  such  30-day  period,  the  holders  of  10%  in
liquidation preference of the outstanding Convertible Preferred Securities  will
be  entitled to convene such meeting.  The provisions of the Limited Partnership
Agreement relating to the convening and conduct of the meetings of the  partners
will  apply  with respect  to any  such meeting.  Any Special  Representative so
appointed shall  cease to  be  a Special  Representative  of COMSAT  Capital  II

                                       26
<PAGE>
and  the  limited partners  if  COMSAT Capital  II  (or COMSAT  pursuant  to the
Guarantee) shall  have paid  in full  all accrued  and unpaid  dividends on  the
Convertible  Preferred Securities or such default or breach, as the case may be,
shall have been cured, and COMSAT, in its capacity as the General Partner, shall
continue the business of COMSAT Capital II without dissolution.  Notwithstanding
the  appointment of  any such Special  Representative, COMSAT  shall continue as
General Partner and shall retain all  rights under the Indenture, including  the
right  to extend the interest  payment period from time to  time to a period not
exceeding  60  consecutive  months  as   provided  under  "Description  of   the
Convertible  Junior Subordinated Debentures -- Option to Extend Interest Payment
Period".

    If any proposed amendment to the Limited Partnership Agreement provides for,
or the General Partner otherwise proposes to effect, (i) any action which  would
adversely  affect the powers,  preferences or special  rights of the Convertible
Preferred Securities, whether  by way  of amendment to  the Limited  Partnership
Agreement  or  otherwise (including,  without  limitation, the  authorization or
issuance of any limited  partner interests in COMSAT  Capital II other than  the
Convertible  Preferred  Securities),  or  (ii)  the  dissolution,  winding-up or
termination of  COMSAT  Capital  II,  other than  (x)  in  connection  with  the
distribution  of Convertible Junior Subordinated  Debentures upon the occurrence
of a  Special  Event  or  (y)  as  described  under  "Merger,  Consolidation  or
Amalgamation  of  COMSAT  Capital II"  above,  then the  holders  of outstanding
Convertible Preferred Securities will be entitled  to vote on such amendment  or
proposal of the General Partner (but not on any other amendment or proposal) and
such  amendment or proposal shall  not be effective except  with the approval of
the holders of 66 2/3% in liquidation preference of such outstanding Convertible
Preferred Securities having a  right to vote on  the matter; provided,  however,
that  no  such approval  shall  be required  if  the dissolution,  winding-up or
termination of COMSAT Capital II is proposed or initiated upon the initiation of
proceedings or  after  proceedings  have been  initiated  for  the  dissolution,
winding-up, liquidation or termination of COMSAT.

    So long as any Convertible Junior Subordinated Debentures are held by COMSAT
Capital  II, the General Partner shall not (i) direct the time, method and place
of conducting any proceeding for any remedy available to the Trustee (as defined
herein), or executing any trust or  power conferred on the Trustee with  respect
to  any series  of Junior Subordinated  Debentures, (ii) waive  any past default
which is waivable under Section 6.06 of the Indenture, (iii) exercise any  right
to  rescind or annul  a declaration that  the principal of  any series of Junior
Subordinated Debentures  shall  be  due  and payable  or  (iv)  consent  to  any
amendment,  modification  or termination  of the  Indenture, where  such consent
shall be required, without,  in each case, obtaining  the prior approval of  the
holders  of  at  least 66  2/3%  in  liquidation preference  of  the Convertible
Preferred  Securities;  provided,  however,  that  where  a  consent  under  the
Indenture  would require  the consent of  each holder affected  thereby, no such
consent shall be given by the General Partner without the prior consent of  each
holder of Convertible Preferred Securities. The General Partner shall not revoke
any  action  previously authorized  or  approved by  a  vote of  the Convertible
Preferred Securities.  The  General Partner  shall  notify all  holders  of  the
Convertible  Preferred Securities  of any  notice of  default received  from the
Trustee with respect to the Convertible Junior Subordinated Debentures.

    Any required approval of holders of Convertible Preferred Securities may  be
given  at  a separate  meeting of  holders  of Convertible  Preferred Securities
convened for such purpose, at a meeting of all of the partners in COMSAT Capital
II or pursuant to written consent. COMSAT Capital II will cause a notice of  any
meeting  at which  holders of Convertible  Preferred Securities  are entitled to
vote, or of any matter upon which  action by written consent of such holders  is
to  be taken,  to be mailed  to each  holder of record  of Convertible Preferred
Securities. Each such notice will include a statement setting forth (i) the date
of such  meeting or  the  date by  which such  action  is to  be taken,  (ii)  a
description  of any  resolution proposed for  adoption at such  meeting on which
such holders are entitled to vote or  of such matter upon which written  consent
is sought and (iii) instructions for the delivery of proxies or consents.

                                       27
<PAGE>
    No  vote or consent of the  holders of Convertible Preferred Securities will
be required for  COMSAT Capital II  to redeem and  cancel Convertible  Preferred
Securities in accordance with the Limited Partnership Agreement.

    Notwithstanding   that  holders  of  Convertible  Preferred  Securities  are
entitled to vote or consent under any of the circumstances described above,  any
of  the Convertible  Preferred Securities  that are  owned by  COMSAT or  by any
entity owned more than  50% by COMSAT,  or by any  entity controlled by  COMSAT,
either  directly or  indirectly, shall  not be entitled  to vote  or consent and
shall, for purposes  of such vote  or consent, be  treated as if  they were  not
outstanding.

    Holders  of  the Convertible  Preferred Securities  will  have no  rights to
remove or replace the General Partner.

BOOK-ENTRY-ONLY ISSUANCE -- THE DEPOSITORY TRUST COMPANY

    DTC  will  act  as  securities  depository  for  the  Convertible  Preferred
Securities.  The  Convertible  Preferred  Securities  will  be  issued  only  as
fully-registered securities  registered  in  the  name  of  Cede  &  Co.  (DTC's
nominee).  One or  more fully-registered  global Convertible  Preferred Security
certificates will be issued, representing in  the aggregate the total number  of
Convertible Preferred Securities, and will be deposited with, DTC.

    DTC  is a limited-purpose trust company organized under the New York Banking
Law, a "banking organization" within the meaning of the New York Banking Law,  a
member  of  the  Federal Reserve  System,  a "clearing  corporation"  within the
meaning of  the  New York  Uniform  Commercial  Code, and  a  "clearing  agency"
registered  pursuant to the provisions  of Section 17A of  the Exchange Act. DTC
holds securities that  its participants ("Participants")  deposit with DTC.  DTC
also  facilitates the settlement among  Participants of securities transactions,
such as  transfers  and  pledges, in  deposited  securities  through  electronic
computerized  book-entry changes in  Participants' accounts, thereby eliminating
the need for physical movement  of securities certificates. Direct  Participants
include  securities  brokers  and  dealers,  banks,  trust  companies,  clearing
corporations and  certain other  organizations ("Direct  Participants"). DTC  is
owned by a number of its Direct Participants and by the NYSE, the American Stock
Exchange,  Inc., and the National Association of Securities Dealers, Inc. Access
to the DTC system  is also available  to others such  as securities brokers  and
dealers,  banks and trust  companies that clear through  or maintain a custodial
relationship with a Direct Participant, either directly or indirectly ("Indirect
Participants"). The rules  applicable to DTC  and its Participants  are on  file
with the Commission.

    Purchases  of Convertible Preferred Securities within the DTC system must be
made by or  through Direct  Participants, which will  receive a  credit for  the
Convertible  Preferred Securities  on DTC's  records. The  ownership interest of
each actual  purchaser  of  each  Convertible  Preferred  Security  ("Beneficial
Owner")  is in  turn to  be recorded  on the  Direct and  Indirect Participants'
records. Beneficial Owners  will not  receive written confirmation  from DTC  of
their   purchases,  but  Beneficial  Owners  are  expected  to  receive  written
confirmations providing  details  of  the  transactions,  as  well  as  periodic
statements  of their holdings, from the  Direct or Indirect Participants through
which  the  Beneficial  Owners   purchased  Convertible  Preferred   Securities.
Transfers  of ownership interests in the Convertible Preferred Securities are to
be accomplished by entries made on the books of Participants acting on behalf of
Beneficial Owners. Beneficial Owners will not receive certificates  representing
their  ownership interests  in Convertible  Preferred Securities,  except in the
event that use of the book-entry system for the Convertible Preferred Securities
is discontinued.

    DTC has no  knowledge of  the actual  Beneficial Owners  of the  Convertible
Preferred  Securities; DTC's  records reflect  only the  identity of  the Direct
Participants  to  whose  accounts  such  Convertible  Preferred  Securities  are
credited,  which may or may not be  the Beneficial Owners. The Participants will
remain responsible for  keeping account  of their  holdings on  behalf of  their
customers.

                                       28
<PAGE>
    Conveyance   of  notices   and  other   communications  by   DTC  to  Direct
Participants, by Direct  Participants to  Indirect Participants,  and by  Direct
Participants  and Indirect Participants to Beneficial Owners will be governed by
arrangements among them, subject to any statutory or regulatory requirements  as
may be in effect from time to time.

    Redemption  notices shall  be sent  to Cede &  Co. If  less than  all of the
Convertible Preferred  Securities  are  being redeemed,  DTC's  practice  is  to
determine  by lot the amount of the  interest of each Direct Participant in such
series to be redeemed.

    Although voting  with respect  to the  Convertible Preferred  Securities  is
limited,  in those cases  where a vote is  required, neither DTC  nor Cede & Co.
will itself consent or  vote with respect  to Convertible Preferred  Securities.
Under its usual procedures, DTC would mail an Omnibus Proxy to COMSAT Capital II
as  soon as  possible after the  record date.  The Omnibus Proxy  assigns Cede &
Co.'s consenting or voting rights to those Direct Participants to whose accounts
the Convertible Preferred Securities are credited on the record date (identified
in a listing attached to the Omnibus Proxy).

    Dividend payments on the  Convertible Preferred Securities  will be made  to
DTC.  DTC's practice is to credit  Direct Participants' accounts on the relevant
payment date in accordance with their respective holdings shown on DTC's records
unless DTC has  reason to  believe that  it will  not receive  payments on  such
payment  date. Payments by Participants to Beneficial Owners will be governed by
standing instructions and customary practices and will be the responsibility  of
such  Participant and not  of DTC, COMSAT  Capital II or  COMSAT, subject to any
statutory or regulatory  requirements as  may be in  effect from  time to  time.
Payment  of  dividends  to  DTC  is the  responsibility  of  COMSAT  Capital II,
disbursement of such payments  to Direct Participants  is the responsibility  of
DTC,  and  disbursement  of  such  payments  to  the  Beneficial  Owners  is the
responsibility of Direct and Indirect Participants.

    DTC may discontinue  providing its  services as  securities depository  with
respect to the Convertible Preferred Securities at any time by giving reasonable
notice  to COMSAT  Capital II.  Under such  circumstances, in  the event  that a
successor securities depository is not obtained, Convertible Preferred  Security
certificates  are  required to  be printed  and delivered.  Additionally, COMSAT
Capital II (with the  consent of COMSAT)  may decide to  discontinue use of  the
system  of book-entry transfers through DTC (or a successor depository). In that
event, certificates for the Convertible Preferred Securities will be printed and
delivered. In each of the above circumstances, the General Partner will  appoint
a paying agent with respect to the Convertible Preferred Securities.

    The  information in this section concerning  DTC and DTC's book-entry system
has been obtained from sources that COMSAT  and COMSAT Capital II believe to  be
reliable,  but neither COMSAT nor COMSAT Capital II takes responsibility for the
accuracy thereof.

REGISTRAR, TRANSFER AGENT, PAYING AGENT AND CONVERSION AGENT

                         will act as registrar, transfer agent, paying agent and
Conversion Agent for the Convertible Preferred Securities.

    Registration of  transfers  of  Convertible  Preferred  Securities  will  be
effected  without charge by or on behalf  of COMSAT Capital II, but upon payment
(with the giving of such indemnity as  COMSAT Capital II or COMSAT may  require)
in  respect  of any  tax or  other government  charges which  may be  imposed in
relation to it.

    COMSAT Capital II will not be required to register or cause to be registered
the  transfer  of  Convertible  Preferred  Securities  after  such   Convertible
Preferred Securities have been called for redemption.

MISCELLANEOUS

    Application will be made to list the Convertible Preferred Securities on the
NYSE.

                                       29
<PAGE>
    The General Partner is authorized and directed to conduct its affairs and to
operate  COMSAT Capital  II in  such a way  that COMSAT  Capital II  will not be
deemed to be an  "investment company" required to  be registered under the  1940
Act  or taxed as a corporation for federal  income tax purposes, and so that the
Convertible Junior Subordinated  Debentures will be  treated as indebtedness  of
COMSAT  for federal income tax purposes. In this connection, the General Partner
is authorized to  take any  action, not  inconsistent with  applicable law,  the
certificate  of limited partnership  or the Limited  Partnership Agreement, that
the General Partner determines  in its discretion to  be necessary or  desirable
for  such  purposes,  as long  as  such  action does  not  adversely  affect the
interests of the holders of the Convertible Preferred Securities.

    Holders of the Convertible Preferred Securities have no preemptive rights.

GOVERNING LAW

    COMSAT Capital II is a limited  partnership organized in Delaware under  the
Delaware  Revised  Uniform  Limited  Partnership  Act.  The  Limited Partnership
Agreement and the Convertible Preferred Securities will be governed by  Delaware
law.

                          DESCRIPTION OF THE GUARANTEE

    SET  FORTH BELOW IS A SUMMARY  OF INFORMATION CONCERNING THE GUARANTEE WHICH
WILL BE EXECUTED AND  DELIVERED BY COMSAT  FOR THE BENEFIT  OF THE HOLDERS  FROM
TIME  TO TIME OF CONVERTIBLE PREFERRED  SECURITIES. THE SUMMARY DOES NOT PURPORT
TO BE COMPLETE  AND IS  SUBJECT IN  ALL RESPECTS TO  THE PROVISIONS  OF, AND  IS
QUALIFIED  IN ITS ENTIRETY BY REFERENCE TO,  THE GUARANTEE, WHICH IS FILED AS AN
EXHIBIT TO THE REGISTRATION STATEMENT OF WHICH THIS PROSPECTUS FORMS A PART.

GENERAL

    Pursuant to  the  Guarantee,  COMSAT will  irrevocably  and  unconditionally
agree,  to the extent  set forth herein, to  pay in full, to  the holders of the
Convertible Preferred Securities, the Guarantee Payments (as defined below),  as
and  when due, regardless of any defense, right of set-off or counterclaim which
COMSAT Capital II may have or assert. The following payments with respect to the
Convertible Preferred Securities, to  the extent not paid  by COMSAT Capital  II
(the   "Guarantee  Payments"),  will  be   subject  to  the  Guarantee  (without
duplication): (i) any accrued and unpaid dividends which are required to be paid
on the Convertible Preferred Securities, to the extent such dividends have  been
declared  by  COMSAT Capital  II out  of moneys  held by  COMSAT Capital  II and
legally available  therefor, (ii)  the Redemption  Price, payable  out of  funds
legally  available therefor with respect to any Convertible Preferred Securities
called for  redemption by  COMSAT Capital  II and  (iii) upon  a liquidation  of
COMSAT Capital II, the lesser of (a) the aggregate of the liquidation preference
and  all accrued and unpaid dividends on the Convertible Preferred Securities to
the date of payment and (b) the amount of assets of COMSAT Capital II  remaining
available  for distribution  to holders  of Convertible  Preferred Securities in
liquidation of  COMSAT  Capital II.  COMSAT's  obligation to  make  a  Guarantee
Payment  may be satisfied by direct payment of the required amounts by COMSAT to
the holders of Convertible Preferred Securities or by causing COMSAT Capital  II
to pay such amounts to such holders.

    If  COMSAT  fails  to  make  interest  payments  on  the  Convertible Junior
Subordinated Debentures purchased by COMSAT  Capital II, COMSAT Capital II  will
have   insufficient  funds  to  pay   dividends  on  the  Convertible  Preferred
Securities. The Guarantee does not cover payment of dividends or the  Redemption
Price  when  COMSAT  Capital II  does  not  have sufficient  funds  to  pay such
dividends or Redemption Price.

    Because the  Guarantee is  a guarantee  of payment  and not  of  collection,
holders  of the  Convertible Preferred  Securities may  proceed directly against
COMSAT as guarantor,  rather than having  to proceed against  COMSAT Capital  II
before    attempting    to   collect    from    COMSAT,   and    COMSAT   waives

                                       30
<PAGE>
any right or remedy to require that any action be brought against COMSAT Capital
II or  any  other  person  or entity  before  proceeding  against  COMSAT.  Such
obligations  will not be discharged except  by payment of the Guarantee Payments
in full.

CERTAIN COVENANTS OF COMSAT

    In the Guarantee,  COMSAT will  covenant that,  so long  as any  Convertible
Preferred  Securities remain  outstanding, COMSAT  will not  declare or  pay any
dividend on, or  redeem, purchase, acquire  or make a  liquidation payment  with
respect   to,  any  of  its  capital  stock   (other  than  as  a  result  of  a
reclassification of capital stock or the exchange or conversion of one class  or
series  of capital stock for  another class or series  of capital stock) or make
any guarantee payment with respect to the  foregoing if at such time (i)  COMSAT
has  exercised its option  to defer interest payments  on the Convertible Junior
Subordinated Debentures and such deferral is continuing, (ii) COMSAT shall be in
default with respect to its payment or other obligations under the Guarantee  or
(iii) there shall have occurred any event that, with the giving of notice or the
lapse of time or both, would constitute an Event of Default under the Indenture.

    COMSAT  will also covenant that, so long as any of the Convertible Preferred
Securities are outstanding, it  will (i) maintain direct  100% ownership of  the
partnership  interests in COMSAT Capital II other than the Convertible Preferred
Securities (except  as permitted  in the  Limited Partnership  Agreement),  (ii)
cause at least 3% of the total value of COMSAT Capital II and at least 3% of all
interest  in the  capital, income,  gain, loss,  deduction and  credit of COMSAT
Capital II  to be  held by  COMSAT, as  General Partner,  (iii) not  voluntarily
dissolve,  wind-up or  liquidate itself  or COMSAT  Capital II,  (iv) remain the
General Partner  and timely  perform all  of its  duties as  General Partner  of
COMSAT  Capital II (including the duty to cause COMSAT Capital II to declare and
pay dividends  on  the Convertible  Preferred  Securities), unless  a  permitted
successor  General Partner  is appointed,  and (v) subject  to the  terms of the
Convertible Preferred Securities, use reasonable efforts to cause COMSAT Capital
II to remain  a Delaware limited  partnership and otherwise  continue not to  be
treated  as an  association taxable as  a corporation for  United States federal
income tax purposes, except, in all  cases, in connection with certain  mergers,
consolidations  or amalgamations permitted by the Limited Partnership Agreement.
See  "Description   of  the   Convertible   Preferred  Securities   --   Merger,
Consolidation or Amalgamation of COMSAT Capital II".

    As  part  of  the  Guarantee,  COMSAT will  agree  that  it  will  honor all
obligations described  therein relating  to the  conversion of  the  Convertible
Preferred  Securities into COMSAT  Common Stock as  described in "Description of
the Convertible Preferred Securities -- Conversion Rights".

AMENDMENTS AND ASSIGNMENT

    Except with respect to any changes which do not adversely affect the  rights
of  holders of Convertible Preferred  Securities (in which case  no vote will be
required), the Guarantee  may be  changed only with  the prior  approval of  the
holders  of not less than  66 2/3% in liquidation  preference of the outstanding
Convertible Preferred Securities. The manner  of obtaining any such approval  of
holders  of  the Convertible  Preferred Securities  will be  as set  forth under
"Description of  the Convertible  Preferred Securities  -- Voting  Rights".  All
guarantees  and agreements contained in the Guarantee shall bind the successors,
assigns, receivers, trustees and  representatives of COMSAT  and shall inure  to
the  benefit  of  the  holders  of  the  Convertible  Preferred  Securities then
outstanding. Except in  connection with  any merger or  consolidation of  COMSAT
with or into another entity or any sale, transfer or lease of COMSAT's assets to
another  entity complying with the provisions under "-- Consolidation, Merger or
Sale of  Assets"  below,  COMSAT may  not  assign  its rights  or  delegate  its
obligations under the Guarantee without the prior approval of the holders of not
less  than 66  2/3% of the  aggregate liquidation preference  of the Convertible
Preferred Securities then outstanding.

TERMINATION OF THE GUARANTEE

    The Guarantee  will terminate  as to  each holder  of Convertible  Preferred
Securities  and be of no  further force and effect upon  (a) full payment of the
Redemption Price of such  holder's Convertible Preferred  Securities or (b)  the
distribution   of  COMSAT  Common  Stock  to  such  holder  in  respect  of  the

                                       31
<PAGE>
conversion of such holder's Convertible Preferred Securities into COMSAT  Common
Stock  and will  terminate completely upon  full payment of  the amounts payable
upon liquidation  of  COMSAT Capital  II.  The  Guarantee will  continue  to  be
effective  or will be reinstated, as the case  may be, if at any time any holder
of Convertible Preferred Securities must restore payment of any sums paid  under
such Convertible Preferred Securities or the Guarantee.

CONSOLIDATION, MERGER OR SALE OF ASSETS

    The  Guarantee provides  that COMSAT may  merge or consolidate  with or into
another entity, may permit another entity  to merge or consolidate with or  into
COMSAT and may sell, transfer or lease all or substantially all of its assets to
another  entity, if (i) at such time no Event of Default shall have occurred and
be continuing, or would occur as a result of such merger, consolidation or sale,
transfer or  lease and  (ii) the  survivor of  such merger  or consolidation  or
entity  to which  COMSAT assets  are sold,  transferred or  leased is  an entity
organized under the laws of the United States of America or any state thereof or
the District of Columbia, becomes the  General Partner, assumes all of  COMSAT's
obligations under the Guarantee and has a net worth equal to at least 10% of the
total contributions to COMSAT Capital II.

STATUS OF THE GUARANTEE -- SUBORDINATION

    The  Guarantee will  constitute an unsecured  obligation of  COMSAT and will
rank (i)  subordinate and  junior in  right  of payment  to all  liabilities  of
COMSAT,  (ii) PARI PASSU with the most  senior preferred or preference stock now
or hereafter issued by  COMSAT and with any  guarantee now or hereafter  entered
into  by COMSAT  in respect  of any preferred  or preference  stock or preferred
securities of  any affiliate  of COMSAT,  and (iii)  senior to  COMSAT's  common
stock.   The  Limited  Partnership  Agreement   provides  that  each  holder  of
Convertible  Preferred   Securities  by   acceptance  thereof   agrees  to   the
subordination  provisions and other terms of the Guarantee. Upon the bankruptcy,
liquidation or winding-up of  COMSAT, its obligations  under the Guarantee  will
rank junior to all its other liabilities (except that such obligations will rank
PARI  PASSU  with  COMSAT's obligations  under  any guarantee  now  or hereafter
entered into  by COMSAT  in respect  of  any preferred  or preference  stock  or
preferred  securities of any affiliate of  COMSAT) and, therefore, funds may not
be available for payment under the Guarantee.  As of March 31, 1995, COMSAT  had
approximately   $1.15  billion  of  indebtedness   or  other  obligations  which
effectively rank senior  to the Guarantee  and no indebtedness  that would  rank
equally with the Guarantee.

    The  Guarantee will constitute a guarantee of payment and not of collection.
The Guarantee will  be deposited with  the General  Partner to be  held for  the
benefit  of the holders of the Convertible Preferred Securities. In the event of
the appointment of a Special Representative to, among other things, enforce  the
Guarantee,  the Special Representative may take  possession of the Guarantee for
such purpose. If  no Special Representative  has been appointed  to enforce  the
Guarantee,  the General Partner has the right to enforce the Guarantee on behalf
of the holders of the Convertible Preferred Securities. The holders of not  less
than  10%  in aggregate  liquidation preference  of all  outstanding Convertible
Preferred Securities have  the right  to direct the  time, method  and place  of
conducting  any proceeding for any remedy available in respect of the Guarantee,
including the  giving  of directions  to  the  General Partner  or  the  Special
Representative,  as  the case  may be.  If  the General  Partner or  the Special
Representative fails to enforce the Guarantee  as above provided, any holder  of
Convertible  Preferred  Securities  may institute  a  legal  proceeding directly
against COMSAT  to  enforce  its  rights  under  the  Guarantee,  without  first
instituting  a legal proceeding against COMSAT Capital II or any other person or
entity. The Guarantee will not be discharged except by payment of the  Guarantee
Payments  in full to  the extent not paid  by COMSAT Capital  II and by complete
performance of all obligations under the Guarantee.

GOVERNING LAW

    The Guarantee will be governed by and construed in accordance with the  laws
of the State of New York.

                                       32
<PAGE>
         DESCRIPTION OF THE CONVERTIBLE JUNIOR SUBORDINATED DEBENTURES

    SET  FORTH BELOW IS A  DESCRIPTION OF THE SPECIFIC  TERMS OF THE CONVERTIBLE
JUNIOR SUBORDINATED DEBENTURES IN WHICH COMSAT  CAPITAL II WILL INVEST WITH  THE
PROCEEDS  OF THE ISSUANCE  AND SALE OF (I)  THE CONVERTIBLE PREFERRED SECURITIES
AND (II)  THE  GENERAL  PARTNER'S  CAPITAL  CONTRIBUTION  WITH  RESPECT  TO  THE
CONVERTIBLE  PREFERRED  SECURITIES  (THE  "GENERAL  PARTNERSHIP  PAYMENT").  THE
FOLLOWING DESCRIPTION DOES NOT  PURPORT TO BE COMPLETE  AND IS QUALIFIED IN  ITS
ENTIRETY   BY  REFERENCE  TO  THE  INDENTURE  (THE  "INDENTURE"),  DATED  AS  OF
            , 1995, BETWEEN COMSAT AND                        , AS TRUSTEE  (THE
"TRUSTEE"),  THE  FORM OF  WHICH  IS FILED  AS  AN EXHIBIT  TO  THE REGISTRATION
STATEMENT OF WHICH THIS PROSPECTUS FORMS A PART. WHENEVER PARTICULAR  PROVISIONS
OR  DEFINED TERMS IN  THE INDENTURE ARE  REFERRED TO HEREIN,  SUCH PROVISIONS OR
DEFINED  TERMS  ARE  INCORPORATED  BY  REFERENCE  HEREIN.  SECTION  AND  ARTICLE
REFERENCES  USED HEREIN  ARE REFERENCES  TO PROVISIONS  OF THE  INDENTURE UNLESS
OTHERWISE NOTED.

    Under certain circumstances involving the  dissolution of COMSAT Capital  II
following the occurrence of a Tax Event or Investment Company Event, Convertible
Junior  Subordinated  Debentures  may  be  distributed  to  the  holders  of the
Convertible Preferred  Securities  in  liquidation of  COMSAT  Capital  II.  See
"Description  of the Convertible Preferred Securities -- Tax Event or Investment
Company Event Redemption or Distribution".

GENERAL

    The Convertible Junior Subordinated Debentures will be issued as a series of
Junior Subordinated  Debentures  under  the Indenture.  The  Convertible  Junior
Subordinated  Debentures  will  be  limited  in  aggregate  principal  amount to
approximately $103.1 million, such amount being the sum of the aggregate  stated
liquidation  preference of the Convertible  Preferred Securities and the General
Partnership Payment. The Indenture does not limit the aggregate principal amount
of Junior Subordinated Debentures  which may be  issued thereunder and  provides
that  the Junior Subordinated  Debentures may be issued  thereunder from time to
time in one or more series.

    The  entire  principal  amount   of  the  Convertible  Junior   Subordinated
Debentures  will become  due and payable,  together with any  accrued and unpaid
interest thereon, including Additional Interest, if any, on             , 2025.

    The Convertible Junior Subordinated Debentures, if distributed to holders of
Convertible Preferred Securities  in a  dissolution of COMSAT  Capital II,  will
initially  be issued as a Global Security.  In the event that Convertible Junior
Subordinated Debentures are issued in certificated form, such Convertible Junior
Subordinated Debentures will be in  denominations of $50 and integral  multiples
thereof and may be transferred or exchanged at the offices described below.

    Payments  on Convertible Junior  Subordinated Debentures issued  as a Global
Security will  be made  to DTC,  as the  depository for  the Convertible  Junior
Subordinated Debentures. In the event Convertible Junior Subordinated Debentures
are  issued in  certificated form, principal  and interest will  be payable, the
transfer of the Convertible Junior  Subordinated Debentures will be  registrable
and   Convertible  Junior  Subordinated  Debentures  will  be  exchangeable  for
Convertible Junior  Subordinated Debentures  of other  denominations of  a  like
aggregate  principal amount at the corporate trust  office of the Trustee in The
City of New  York; provided,  that, unless the  Convertible Junior  Subordinated
Debentures  are held  by COMSAT  Capital II  or any  successor permissible under
"Description of the Convertible Preferred Securities -- Merger, Consolidation or
Amalgamation of  COMSAT Capital  II", payment  of interest  may be  made at  the
option of COMSAT by check mailed to the address of the persons entitled thereto.

    If  the Convertible  Junior Subordinated  Debentures are  distributed to the
holders of  Convertible  Preferred Securities  upon  the dissolution  of  COMSAT
Capital  II, COMSAT  will use  its best efforts  to list  the Convertible Junior
Subordinated Debentures on the NYSE or on such other exchange as the Convertible
Preferred Securities are then  listed and traded  on the same  part of any  such
exchange.

                                       33
<PAGE>
    The  Indenture  does  not  contain any  provisions  that  afford  holders of
Convertible Junior Subordinated Debentures protection  in the event of a  highly
leveraged transaction involving COMSAT.

INTEREST

    Each  Convertible Junior  Subordinated Debenture  will bear  interest at the
rate of    % per annum from  the original date of  issuance, payable monthly  in
arrears  on the last day of each calendar month of each year (each, an "Interest
Payment Date"), commencing             , 1995, to the person in whose name  such
Convertible  Junior  Subordinated Debenture  is  registered, subject  to certain
exceptions, at the  close of business  on the Business  Day next preceding  such
Interest  Payment Date;  provided, however,  that in  the event  the Convertible
Junior Subordinated Debentures shall not  continue to remain in  book-entry-only
form,  COMSAT shall have  the right to  select record dates  which shall be more
than one Business Day prior to the Interest Payment Date. Interest will compound
monthly and will accrue at  the annual rate of    % on any interest  installment
not paid when due.

    The  amount of interest payable for any period will be computed on the basis
of a 360-day year of twelve 30-day months.  In the event that any date on  which
interest  is payable on the Convertible  Junior Subordinated Debentures is not a
Business Day, then payment of the interest payable on such date will be made  on
the  next succeeding day  which is a  Business Day (and  without any interest or
other payment in respect of any such  delay), except that, if such Business  Day
is  in the  next succeeding  calendar year,  such payment  shall be  made on the
immediately preceding Business Day, in each case with the same force and  effect
as if made on such date.

OPTION TO EXTEND INTEREST PAYMENT PERIOD

    COMSAT  shall have the right at any  time during the term of the Convertible
Junior Subordinated Debentures to extend  the interest payment period from  time
to  time  to  a  period  not exceeding  60  consecutive  months  (the "Extension
Period"), at the  end of which  Extension Period COMSAT  shall pay all  interest
then  accrued and unpaid  (together with interest thereon  at the rate specified
for the Convertible Junior  Subordinated Debentures to  the extent permitted  by
applicable  law).  In no  event  shall any  Extension  Period extend  beyond the
maturity of the Convertible Junior Subordinated Debentures. During any Extension
Period, COMSAT shall not  declare or pay any  dividend on, or redeem,  purchase,
acquire or make a liquidation payment with respect to, any of its capital stock.
Prior to the termination of any such Extension Period, COMSAT may further extend
the  interest payment period, provided that  such Extension Period together with
all such previous and further extensions  thereof may not exceed 60  consecutive
months.  Upon the  termination of  any Extension Period  and the  payment of all
amounts then due, COMSAT may select a new Extension Period, subject to the above
requirements. No interest during an Extension Period, except at the end thereof,
shall be due and payable. If COMSAT Capital  II shall be the sole holder of  the
Convertible  Junior Subordinated Debentures, COMSAT shall give COMSAT Capital II
notice of its selection of such Extension  Period one Business Day prior to  the
earlier  of (i) the  date the dividends on  the Convertible Preferred Securities
are payable or (ii) the date COMSAT Capital II is required to give notice to the
NYSE or  other applicable  self-regulatory  organization or  to holders  of  the
Convertible Preferred Securities of the record date or the date such dividend is
payable,  but in any event  not less than one Business  Day prior to such record
date. COMSAT shall cause COMSAT Capital II to give notice of COMSAT's  selection
of such Extension Period to the holders of the Convertible Preferred Securities.
If  COMSAT Capital  II shall not  be the  sole holder of  the Convertible Junior
Subordinated Debentures, COMSAT shall give the holders of the Convertible Junior
Subordinated Debentures notice  of its  selection of such  Extension Period  ten
Business  Days prior to the earlier of (i) the Interest Payment Date or (ii) the
date COMSAT  is  required  to  give  notice to  the  NYSE  or  other  applicable
self-regulatory   organization,  or   to  holders  of   the  Convertible  Junior
Subordinated Debentures, of the record or payment date of such related  interest
payment,  but in any event not less than  two Business Days prior to such record
date.

ADDITIONAL INTEREST

    If at any time COMSAT  Capital II shall be required  to pay any interest  on
dividends  in respect  of the Convertible  Preferred Securities  pursuant to the
terms thereof, then COMSAT will pay as interest

                                       34
<PAGE>
to COMSAT  Capital II  as  the holder  of  the Convertible  Junior  Subordinated
Debentures ("Additional Interest") an amount equal to such interest on dividends
in  arrears. In  addition, if  COMSAT Capital  II would  be required  to pay any
taxes, duties, assessments  or governmental  charges of  whatever nature  (other
than  withholding  taxes) imposed  by  the United  States,  or any  other taxing
authority, then, in any such case,  COMSAT also will pay as Additional  Interest
such  amounts as shall be required so that the net amounts received and retained
by COMSAT  Capital  II after  paying  any  such taxes,  duties,  assessments  or
governmental  charges will be not less than  the amounts COMSAT Capital II would
have received had  no such  taxes, duties, assessments  or governmental  charges
been imposed.

CONVERSION OF THE CONVERTIBLE JUNIOR SUBORDINATED DEBENTURES

    The  Convertible  Junior Subordinated  Debentures  will be  convertible into
COMSAT Common  Stock at  the option  of the  holders of  the Convertible  Junior
Subordinated Debentures at any time at the initial conversion price set forth on
the  cover page of  this Prospectus subject to  the conversion price adjustments
described  under  "Description  of  the  Convertible  Preferred  Securities   --
Conversion  Rights". COMSAT Capital II will  covenant not to convert Convertible
Junior Subordinated  Debentures  except  pursuant  to  a  notice  of  conversion
delivered  to  the  Conversion  Agent  by  a  holder  of  Convertible  Preferred
Securities. Upon surrender of a Convertible Preferred Security to the Conversion
Agent for conversion, COMSAT Capital II will distribute $50 principal amount  of
the Convertible Junior Subordinated Debentures to the Conversion Agent on behalf
of  the holder of the Convertible Preferred Security so converted, whereupon the
Conversion Agent will convert such Convertible Junior Subordinated Debentures to
COMSAT Common Stock on behalf of  such holder. COMSAT's delivery to the  holders
of the Convertible Junior Subordinated Debentures (through the Conversion Agent)
of  the fixed number of shares of COMSAT Common Stock into which the Convertible
Junior Subordinated Debentures are convertible (together with the cash  payment,
if  any,  in lieu  of  fractional shares)  will  be deemed  to  satisfy COMSAT's
obligation to pay the  principal amount of  the Convertible Junior  Subordinated
Debentures   so  converted,  and   the  accrued  and   unpaid  interest  thereon
attributable to the period from the last date to which interest has been paid or
duly  provided  for;   provided,  however,  that   if  any  Convertible   Junior
Subordinated  Debenture  is  converted  between a  record  date  for  payment of
interest and the related payment date,  the interest payable on such  succeeding
interest  payment  date with  respect  to such  Convertible  Junior Subordinated
Debenture shall be paid despite such conversion.

MANDATORY PREPAYMENT

    If COMSAT Capital II redeems Convertible Preferred Securities in  accordance
with  the  terms thereof,  the Convertible  Junior Subordinated  Debentures will
become due  and payable  in a  principal amount  equal to  the aggregate  stated
liquidation  preference  of the  Convertible  Preferred Securities  so redeemed,
together with  any accrued  and unpaid  interest thereon,  including  Additional
Interest,  if any. Any payment pursuant to this provision shall be made prior to
12:00 noon, New York time, on the date of such redemption or at such other  time
on  such  earlier  date  as  COMSAT  and  COMSAT  Capital  II  shall  agree. The
Convertible Junior Subordinated Debentures  are not entitled  to the benefit  of
any sinking fund.

OPTIONAL REDEMPTION

    COMSAT  shall have the  right to redeem  the Convertible Junior Subordinated
Debentures without premium or penalty, in whole or in part, concurrent with  the
redemption  by COMSAT Capital II of the Convertible Preferred Securities (if any
Convertible Preferred Securities are then outstanding), at any time or from time
to time on or after              ,     , upon not less than 30 nor more than  60
days'  notice, at a redemption price equal to 100% of the principal amount to be
redeemed plus any accrued and unpaid interest, including Additional Interest, if
any, to the redemption date.

    In the event of any redemption in part, COMSAT shall not be required to  (i)
issue,  register the transfer of or exchange any Convertible Junior Subordinated
Debenture during a period  beginning at the opening  of business 15 days  before
any  selection for redemption of  Convertible Junior Subordinated Debentures and
ending at the  close of  business on  the earliest  date in  which the  relevant
notice

                                       35
<PAGE>
of  redemption is deemed to have been given to all holders of Convertible Junior
Subordinated Debentures  and  (ii) register  the  transfer of  or  exchange  any
Convertible  Junior Subordinated Debentures so selected for redemption, in whole
or in part, except the unredeemed portion of any Convertible Junior Subordinated
Debenture being redeemed in part. (Section 2.05).

SUBORDINATION

    The Indenture provides that  the Convertible Junior Subordinated  Debentures
are  subordinate and junior  in right of  payment to all  Senior Indebtedness of
COMSAT as  provided in  the Indenture.  No payment  of principal  of  (including
redemption  payments),  or  interest  on,  the  Convertible  Junior Subordinated
Debentures may be made (i) if any Senior Indebtedness is not paid when due,  any
applicable  grace period with respect to such default has ended and such default
has not been cured or waived, or (ii) if the maturity of any Senior Indebtedness
has been accelerated because  of a default. Upon  any distribution of assets  of
COMSAT   to  creditors   upon  any   dissolution,  winding-up,   liquidation  or
reorganization, whether voluntary or  involuntary or in bankruptcy,  insolvency,
receivership  or other proceedings,  all principal of, and  premium, if any, and
interest due or to become due on,  all Senior Indebtedness must be paid in  full
before  the  holders  of  the  Convertible  Junior  Subordinated  Debentures are
entitled to receive  or retain any  payment. The  rights of the  holders of  the
Convertible  Junior Subordinated Debentures will be  subrogated to the rights of
the  holders  of  Senior  Indebtedness  to  receive  payments  or  distributions
applicable  to Senior  Indebtedness until all  amounts owing  on the Convertible
Junior Subordinated  Debentures are  paid in  full. (Sections  14.01 to  14.03).
However, since Senior Indebtedness currently is not secured and ranks PARI PASSU
with  other unsecured indebtedness of COMSAT, rights of subrogation currently do
not improve the position of the  holders of the Convertible Junior  Subordinated
Debentures  in relation  to the holders  of any other  unsecured indebtedness of
COMSAT.

    The term "Senior Indebtedness" shall mean the principal of, premium, if any,
interest on and any other payment due pursuant to any of the following,  whether
outstanding  at the date  of execution of the  Indenture or thereafter incurred,
created  or  assumed:  (i)  all  indebtedness  of  COMSAT  evidenced  by  notes,
debentures,  bonds  or  other securities  sold  by  COMSAT for  money;  (ii) all
indebtedness of  others of  the  kinds described  in  the preceding  clause  (i)
assumed  by or  guaranteed in any  manner by  COMSAT or in  effect guaranteed by
COMSAT; and (iii) all renewals, extensions or refundings of indebtedness of  the
kinds described in any of the preceding clauses (i) and (ii); provided, however,
that   the  following  shall   not  constitute  Senior   Indebtedness:  (a)  any
indebtedness of COMSAT  to any subsidiary  of COMSAT, or  (b) any  indebtedness,
which  by the terms of the instrument  creating or evidencing the same expressly
provides that such indebtedness  is not superior  in right of  payment to or  is
PARI  PASSU  with the  Convertible Junior  Subordinated Debentures.  Such Senior
Indebtedness shall  continue  to be  Senior  Indebtedness and  entitled  to  the
benefits   of  the  subordination  provisions  irrespective  of  any  amendment,
modification or waiver of any term of such Senior Indebtedness. (Section 1.01).

    The Indenture does  not limit  the aggregate amount  of Senior  Indebtedness
which may be issued. At March 31, 1995, Senior Indebtedness of COMSAT aggregated
approximately $751 million.

CERTAIN COVENANTS OF COMSAT

    COMSAT  will covenant that  it will not  declare or pay  any dividend on, or
redeem, purchase, acquire  or make  a distribution or  liquidation payment  with
respect  to, any  of its  capital stock, if  at such  time (i)  there shall have
occurred any  event  that  would  constitute  an  Event  of  Default  under  the
Indenture,  (ii) COMSAT shall be  in default with respect  to its payment of any
obligations under the Guarantee or (iii)  COMSAT shall have given notice of  its
selection  of an extended  interest payment period as  provided in the Indenture
and such period, or any extension thereof, shall be continuing. (Section  4.06).
COMSAT  will also  covenant (i)  to remain  the sole  general partner  of COMSAT
Capital II  and maintain  100% ownership  of the  general partnership  interests
thereof; provided that any permitted successor of COMSAT under the Indenture may
succeed  to COMSAT's duties as General Partner, (ii) to contribute capital in an
amount equal to at least 3% of the total capital

                                       36
<PAGE>
contributions to COMSAT Capital II,  (iii) not to voluntarily dissolve,  wind-up
or  terminate COMSAT Capital  II, except in connection  with the distribution of
Convertible  Junior  Subordinated  Debentures   to  the  holders  of   Preferred
Securities  in liquidation of  COMSAT Capital II and  in connection with certain
mergers, consolidations or  amalgamations permitted by  the Limited  Partnership
Agreement,  (iv) to timely perform  all of its duties  as the general partner in
COMSAT Capital  II (including  the  duty to  pay  dividends on  the  Convertible
Preferred Securities), (v) to use its reasonable efforts to cause COMSAT Capital
II  to remain a  limited partnership except in  connection with certain mergers,
consolidations or amalgamations permitted  by the Limited Partnership  Agreement
and  otherwise  continue  not to  be  treated  as an  association  taxable  as a
corporation for United States  federal income tax purposes  and (vi) to  deliver
shares  of COMSAT Common  Stock upon an  election by the  holders of Convertible
Preferred Securities to convert the Convertible Junior Subordinated  Debentures.
(Section 4.07).

EVENTS OF DEFAULT

    The  Indenture  provides that  any one  or more  of the  following described
events, which has occurred and is continuing, constitutes an "Event of  Default"
with  respect to the Convertible Junior Subordinated Debentures: (i) failure for
10 days  to pay  interest  on the  Convertible Junior  Subordinated  Debentures,
including  any Additional Interest in respect thereof, when due; or (ii) failure
to pay principal  or premium,  if any,  on the  Convertible Junior  Subordinated
Debentures  when  due whether  at maturity,  upon  redemption by  declaration or
otherwise; or (iii) failure by COMSAT  to deliver shares of COMSAT Common  Stock
upon an election by a holder of Convertible Preferred Securities to convert such
Convertible  Preferred Securities;  or (iv)  failure to  observe or  perform any
other covenant  (other than  those specifically  relating to  another series  of
Junior  Subordinated Debentures)  contained in the  Indenture for  90 days after
notice; or (v) the dissolution, winding-up or termination of COMSAT Capital  II,
except  in connection with  the distribution of  Convertible Junior Subordinated
Debentures to the holders of Convertible Preferred Securities in liquidation  of
COMSAT  Capital II  and in  connection with  certain mergers,  consolidations or
amalgamations permitted by  the Limited Partnership  Agreement; or (vi)  certain
events in bankruptcy, insolvency or reorganization of COMSAT. (Section 6.01).

    The  Trustee or the  holders of not  less than 25%  in aggregate outstanding
principal amount of the Convertible  Junior Subordinated Debentures may  declare
the  principal  of  and  interest (including  any  Additional  Interest)  on the
Convertible Junior  Subordinated  Debentures  due  and  payable  immediately  on
default  with  respect  to  such  series;  provided,  however,  that  after such
acceleration, but before a judgment or decree based on acceleration, the holders
of a majority in  aggregate principal amount  of outstanding Convertible  Junior
Subordinated Debentures may, under certain circumstances, rescind and annul such
acceleration  if all Events of  Default with respect to  such series, other than
the non-payment of accelerated principal, have been cured or waived as  provided
in the Indenture. For information as to waiver of defaults, see "-- Modification
of the Indenture".

    COMSAT   Capital  II  is  the  initial  holder  of  the  Convertible  Junior
Subordinated Debentures. However, while the Convertible Preferred Securities are
outstanding, COMSAT Capital II has agreed not to waive an Event of Default  with
respect to the Convertible Junior Subordinated Debentures without the consent of
holders  of  66  2/3% in  aggregate  liquidation preference  of  the Convertible
Preferred Securities then outstanding. A default under any other indebtedness of
COMSAT or COMSAT Capital II would not  constitute an Event of Default under  the
Convertible Junior Subordinated Debentures.

    Subject  to the  provision of  the Indenture relating  to the  duties of the
Trustee in case an Event of Default  shall occur and be continuing, the  Trustee
will  be under no obligation  to exercise any of its  rights or powers under the
Indenture at  the request  or direction  of any  holders of  Convertible  Junior
Subordinated  Debentures, unless such holders shall  have offered to the Trustee
reasonable indemnity.

                                       37
<PAGE>
Subject to such provisions for the  indemnification of the Trustee, the  holders
of  a majority in aggregate principal  amount of Convertible Junior Subordinated
Debentures then outstanding will have the  right to direct the time, method  and
place  of conducting any proceeding for any  remedy available to the Trustee, or
exercising any trust  or power  conferred on the  Trustee with  respect to  such
series.

    No  holder of  any Convertible Junior  Subordinated Debenture  will have any
right to  institute any  proceeding with  respect to  the Indenture  or for  any
remedy thereunder, unless such holder shall have previously given to the Trustee
written notice of a continuing Event of Default and, if COMSAT Capital II is not
the  sole holder of Convertible Junior  Subordinated Debentures, unless also the
holders of at least 25% in aggregate principal amount of the Convertible  Junior
Subordinated  Debentures then outstanding  shall have made  written request, and
offered reasonable indemnity,  to the  Trustee to institute  such proceeding  as
Trustee,  and the Trustee shall not have received from the holders of a majority
in aggregate principal amount of the outstanding Convertible Junior Subordinated
Debentures a direction inconsistent with such  request and shall have failed  to
institute such proceeding within 60 days. However, such limitations do not apply
to  a suit instituted by a holder of a Convertible Junior Subordinated Debenture
for enforcement of payment of the  principal of or interest on such  Convertible
Junior  Subordinated Debenture on or after the respective due dates expressed in
such Convertible Junior Subordinated Debenture (Sections 6.01 and 6.06).

    The holders of a majority in  aggregate outstanding principal amount of  all
series  of the Junior Subordinated Debentures affected thereby may, on behalf of
the holders of all the Junior Subordinated Debentures of such series, waive  any
past  default, except a default in the payment of principal, premium, if any, or
interest. (Section 6.06). COMSAT is required to file annually with the Trustee a
certificate as to whether or not COMSAT is in compliance with all the conditions
and covenants under the Indenture. (Section 5.03(d)).

ENFORCEMENT OF CERTAIN RIGHTS BY SPECIAL REPRESENTATIVE

    If (i) COMSAT Capital II fails to  pay dividends in full on the  Convertible
Preferred  Securities for 18 consecutive monthly dividend periods; (ii) an Event
of Default  occurs and  is  continuing on  the Convertible  Junior  Subordinated
Debentures;  or  (iii) COMSAT  is  in default  on any  of  its payment  of other
obligations under the Guarantee,  under the terms  of the Convertible  Preferred
Securities,  the holders  of outstanding  Convertible Preferred  Securities will
have the  rights referred  to under  "Description of  the Convertible  Preferred
Securities  --  Voting  Rights",  including  the  right  to  appoint  a  Special
Representative, which  Special Representative  shall be  authorized to  exercise
COMSAT  Capital II's right to accelerate the principal amount of the Convertible
Junior Subordinated Debentures and to enforce COMSAT Capital II's other creditor
rights under the Convertible Junior Subordinated Debentures. Notwithstanding the
appointment of any such Special Representative, COMSAT shall continue as General
Partner and shall retain all rights under the Indenture, including the right  to
extend  the interest payment period from time  to time to a period not exceeding
60 consecutive months.

MODIFICATION OF THE INDENTURE

    The Indenture contains  provisions permitting COMSAT  and the Trustee,  with
the  consent of the holders  of not less than a  majority in principal amount of
the Junior Subordinated  Debentures of  each series  which are  affected by  the
modification,  to modify the  Indenture or any  supplemental indenture affecting
that series or the rights of the  holders of that series of Junior  Subordinated
Debentures;  provided, that no such modification may, without the consent of the
holder of each outstanding Junior  Subordinated Debenture affected thereby,  (i)
extend  the fixed maturity of any  Junior Subordinated Debentures of any series,
or reduce the principal amount thereof, or reduce the rate or extend the time of
payment of interest thereon, or reduce  any premium payable upon the  redemption
thereof,   or  adversely  affect   the  right  to   convert  Convertible  Junior
Subordinated Debentures,  without  the consent  of  the holder  of  each  Junior
Subordinated   Debenture  so   affected  or   (ii)  reduce   the  percentage  of

                                       38
<PAGE>
Junior Subordinated Debentures, the holders of which are required to consent  to
any  such supplemental  indenture, without  the consent  of the  holders of each
Junior Subordinated Debenture  then outstanding and  affected thereby.  (Section
9.02).

    In  addition, COMSAT and the Trustee may execute, without the consent of any
holder of Convertible Junior Subordinated Debentures, any supplemental indenture
for certain other  usual purposes including  the creation of  any new series  of
Junior Subordinated Debentures. (Sections 2.01, 9.01 and 10.01).

CONSOLIDATION, MERGER OR SALE OF ASSETS

    The Indenture does not contain any covenant which restricts COMSAT's ability
to  merge or consolidate with or into  any other corporation, sell or convey all
or substantially  all  of its  assets  to any  person,  firm or  corporation  or
otherwise engage in restructuring transactions. (Section 10.01).

SET-OFF

    Notwithstanding anything to the contrary in the Indenture, COMSAT shall have
the  right  to  set-off  any  payment with  respect  to  the  Convertible Junior
Subordinated Debentures it is otherwise required to make thereunder with and  to
the  extent COMSAT has theretofore made, or  is concurrently on the date of such
payment making, a payment under the Guarantee.

GOVERNING LAW

    The Indenture and  the Convertible  Junior Subordinated  Debentures will  be
governed  by, and  construed in accordance  with, the  laws of the  State of New
York. (Section 13.05).

INFORMATION CONCERNING THE TRUSTEE

    The Trustee, prior to default, undertakes to perform only such duties as are
specifically set forth in the Indenture  and, after default, shall exercise  the
same degree of care as a prudent individual would exercise in the conduct of his
or  her own affairs. (Section  7.01). Subject to such  provision, the Trustee is
under no obligation to exercise any of the powers vested in it by the  Indenture
at  the request  of any  holder of  Convertible Junior  Subordinated Debentures,
unless offered reasonable indemnity by  such holder against the costs,  expenses
and  liabilities which might be incurred thereby. (Section 7.02). The Trustee is
not required  to  expend or  risk  its own  funds  or otherwise  incur  personal
financial  liability in the performance of  its duties if the Trustee reasonably
believes that repayment or adequate indemnity  is not reasonably assured to  it.
(Section 7.01).

                        EFFECT OF OBLIGATIONS UNDER THE
          CONVERTIBLE JUNIOR SUBORDINATED DEBENTURES AND THE GUARANTEE

    As  set  forth in  the Limited  Partnership Agreement,  the sole  purpose of
COMSAT Capital II is to issue  the Convertible Preferred Securities and use  the
proceeds  thereof to  purchase from  COMSAT the  Convertible Junior Subordinated
Debentures.

    As long as payments of interest and other payments are made when due on  the
Convertible  Junior Subordinated Debentures, such payments will be sufficient to
cover dividends  and  payments  due  on  the  Convertible  Preferred  Securities
primarily  because  (i) the  aggregate  principal amount  of  Convertible Junior
Subordinated Debentures  will  be equal  to  the  sum of  the  aggregate  stated
liquidation  preference of the Convertible  Preferred Securities and the General
Partnership Payment; (ii) the interest rate and interest and other payment dates
on the Convertible Junior Subordinated  Debentures will match the dividend  rate
and  dividend and other payment dates  for the Convertible Preferred Securities;
(iii) the  Limited  Partnership  Agreement  provides  that  COMSAT,  as  General
Partner, shall pay for all, and COMSAT Capital II shall not be obligated to pay,
directly  or indirectly, for any,  costs and expenses of  COMSAT Capital II; and
(iv) the Limited Partnership Agreement further provides that the General Partner
shall not cause or permit  COMSAT Capital II to,  among other things, engage  in
any activity that is not consistent with the purposes of COMSAT Capital II.

                                       39
<PAGE>
    If COMSAT fails to make interest or other payments on the Convertible Junior
Subordinated  Debentures when due, the  Limited Partnership Agreement provides a
mechanism whereby  the  holders  of the  Convertible  Preferred  Securities  may
enforce   the  rights  of  COMSAT  Capital   II  under  the  Convertible  Junior
Subordinated Debentures  through the  appointment of  a Special  Representative.
Payments  of  dividends  and other  payments  due on  the  Convertible Preferred
Securities out of moneys held by COMSAT  Capital II are guaranteed by COMSAT  to
the  extent  set  forth  under  "Description  of  the  Guarantee".  The  Limited
Partnership  Agreement  also   provides,  and  COMSAT,   under  the   Guarantee,
acknowledges,  that a  Special Representative  may be  appointed to  enforce the
Guarantee if COMSAT is in  default on any of  its payment obligations under  the
Guarantee.  In addition,  if the General  Partner or  the Special Representative
fails to enforce the Guarantee, a holder of a Convertible Preferred Security may
institute a legal proceeding directly against COMSAT to enforce its rights under
the Guarantee  without  first  instituting a  legal  proceeding  against  COMSAT
Capital II or any other person or entity.

    COMSAT  and  COMSAT  Capital  II  believe  that  the  above  mechanisms  and
obligations,  taken  together,  are  substantially  equivalent  to  a  full  and
unconditional  guarantee by COMSAT of payments  due on the Convertible Preferred
Securities.

                      DESCRIPTION OF COMSAT CAPITAL STOCK

    The following  is a  brief description  of the  capital stock  of COMSAT  as
provided for in the COMSAT Articles of Incorporation (the "COMSAT Articles") and
the  Satellite Act.  This description  does not  purport to  be complete  and is
qualified in its entirety by reference to  the full text of the COMSAT  Articles
and the relevant provisions of the Satellite Act, each of which is an exhibit to
the Registration Statement of which this Prospectus is a part.

    The Satellite Act and the COMSAT Articles create a number of restrictions on
the  rights of holders of COMSAT capital stock. The limitations contained in the
COMSAT Articles and  the Satellite  Act may restrict  the ability  of COMSAT  to
issue  shares of COMSAT Common  Stock to certain persons  in connection with the
conversion  of   Convertible   Preferred  Securities   or   Convertible   Junior
Subordinated  Debentures into  COMSAT Common Stock  and may limit  the rights of
certain shareholders to own, transfer and vote shares of COMSAT Common Stock.

    The COMSAT Articles currently authorize  the issuance of 105,000,000  shares
of  capital stock,  including 5,000,000 shares  of preferred  stock, without par
value ("COMSAT  Preferred  Stock"),  and 100,000,000  shares  of  common  stock,
without  par value.  As of  March 31, 1995,  47,143,071 shares  of COMSAT Common
Stock were outstanding.  As of that  date, no shares  of COMSAT Preferred  Stock
were issued or outstanding.

GENERAL

    The Satellite Act and the COMSAT Articles impose three major restrictions on
the ownership, transfer and voting of shares of COMSAT capital stock.

    COMMON CARRIERS.  The Satellite Act provides that only those Common Carriers
(as  defined below) which are specifically authorized  or which are members of a
class of carriers authorized by the FCC to own COMSAT Common Stock  ("Authorized
Carriers")  may  own  shares of  COMSAT  capital  stock, and  at  no  time shall
Authorized Carriers directly or indirectly own in the aggregate more than 50% of
the capital stock of COMSAT. See "-- Provisions Pertaining to Common  Carriers".
The  Satellite Act provides further that Common Carriers as a group are entitled
to elect directors separately from  the other shareholders when Common  Carriers
own  or hold  more than 8%  of the capital  stock. The number  of directors that
Common Carriers are entitled to elect  is specified by formula in the  Satellite
Act.  See "-- Voting  Rights; Election of  Directors". Common Carriers currently
own or hold less  than 8% of  the capital stock.  The COMSAT Articles  designate
shares  of COMSAT  Common Stock  held by persons  other than  Common Carriers as
Series I shares and shares of Common Stock held by Common Carriers as Series  II
shares. See "-- Common Stock".

                                       40
<PAGE>
    ALIEN  PERSONS.  The  Satellite Act provides that  Alien Persons (as defined
below) may not own or hold more than 20% of the aggregate number of  outstanding
shares  of COMSAT capital stock held by  persons other than Common Carriers. See
"-- Restrictions on Ownership and Transfer of Shares".

    HOLDINGS BY ANY PERSON,  SYNDICATE OR AFFILIATED GROUP.   The Satellite  Act
provides  that no person,  syndicate or affiliated group  of such persons (other
than a Common Carrier) may own or hold more than 10% of the aggregate number  of
outstanding  shares of COMSAT capital stock.  Pursuant to authority contained in
the COMSAT  Articles,  COMSAT's Board  of  Directors (the  "COMSAT  Board")  may
determine  by resolution that such  percentage may be less  than 10%. The COMSAT
Board has determined  that the ownership  limitation shall be  10%, but that  no
person,  syndicate  or affiliated  group of  such persons  (other than  a Common
Carrier) may  vote shares  held  in excess  of 5%  of  the aggregate  number  of
outstanding  shares of COMSAT  capital stock. See  "-- Restrictions on Ownership
and Transfer of Shares" and "-- Voting Rights; Election of Directors".

COMMON STOCK

    All shares of COMSAT Common Stock  are designated by the COMSAT Articles  as
either  Series I or Series II shares  depending upon the character of the holder
of such shares. Shares of COMSAT  Common Stock issued or transferred to  persons
other  than Common Carriers are designated  Series I shares ("Series I shares").
"Common Carrier" means  (i) any person  (other than COMSAT)  engaged within  the
United   States  as  a  common  carrier  for  hire,  in  interstate  or  foreign
communication by wire or  radio or interstate or  foreign radio transmission  of
energy; or (ii) any person which owns or controls, directly or indirectly, or is
under  direct or indirect common control with, any such person. A person engaged
in radio broadcasting  is not,  insofar as  so engaged,  deemed to  be a  Common
Carrier.  Shares  of COMSAT  Common Stock  issued  or transferred  to Authorized
Carriers are  designated  Series  II  shares ("Series  II  shares").  Except  as
described  below, the rights of a holder of  Series I shares and the rights of a
holder of Series II shares are the  same. Accordingly, subject to the rights  of
the  holders of  COMSAT Preferred  Stock, if any,  all holders  of COMSAT Common
Stock are entitled to receive  such dividends as may  be declared by the  COMSAT
Board   out  of  funds   legally  available  therefor.   Upon  any  liquidation,
dissolution, or winding up of  COMSAT, subject to the  rights of the holders  of
COMSAT Preferred Stock, if any, all holders of shares of COMSAT Common Stock are
entitled  to receive, pro rata, the assets of COMSAT available for distribution.
No conversion rights, preemptive rights  or redemption rights are applicable  to
shares of COMSAT Common Stock.

    The  total number of Series I shares  and Series II shares outstanding as of
March 31, 1995 was 47,122,247 shares and 20,824 shares, respectively. Series  II
shares constituted less than 0.1% of the outstanding shares as of such date.

PREFERRED STOCK

    The  COMSAT Articles provide that the COMSAT Preferred Stock, if issued, (i)
shall have voting rights  equivalent to the  Series I shares,  (ii) may only  be
held  by persons who  are not Common  Carriers or subsidiaries  or affiliates of
Common Carriers  or  are  not  trustees  or  directors  of  Common  Carriers  or
subsidiaries  or affiliates of  Common Carriers, (iii)  shall be aggregated with
the Series I shares in determining  compliance with the restrictions on  foreign
ownership,  (iv)  shall be  aggregated  with shares  of  COMSAT Common  Stock in
determining the number of outstanding shares and compliance with the restriction
on the amount of COMSAT's capital stock that may be held by non-Common Carriers,
(v) if entitled to  dividends, shall be entitled  to cumulative dividends,  (vi)
shall  have no preemptive rights, and (vii) with respect to shares of any series
of COMSAT  Preferred  Stock, may,  if  so determined  by  the COMSAT  Board,  be
convertible  into shares  of another  class of  COMSAT capital  stock or another
series of COMSAT Preferred Stock.

    No dividends may be declared or paid on any COMSAT Common Stock nor,  except
in  limited  cases, may  any COMSAT  Common  Stock be  purchased or  redeemed by
COMSAT, unless all dividends on all series of COMSAT Preferred Stock shall  have
been paid or declared and a sum sufficient for the payment thereof set aside. In
the   event  of   any  liquidation,  dissolution   or  winding   up  of  COMSAT,

                                       41
<PAGE>
before any payment is  made to holders  of COMSAT Common  Stock, the holders  of
COMSAT  Preferred Stock shall be  entitled to be paid  in full their liquidation
preference as fixed in the resolutions  of the COMSAT Board issuing such  stock,
together with accrued dividends.

    The  COMSAT Articles provide that the  COMSAT Board shall have the authority
to fix the relative rights and preferences of the shares of any series of COMSAT
Preferred Stock generally as follows: (i) the serial designation of such series,
(ii) the number of shares  included in such series,  (iii) the dividend rate  of
the  series, (iv)  the date  from which dividends  shall be  cumulative, (v) the
liquidation preference  of  the series,  (vi)  the provisions  relating  to  the
redemption  of shares of the  series, (vii) the obligations  to create a sinking
fund to purchase  or redeem  shares, (viii)  the conversion  privileges of  such
shares  into any  other class  of COMSAT  capital stock  or any  other series of
COMSAT Preferred Stock, and  (ix) any other relative  rights or preferences  not
inconsistent with the COMSAT Articles or applicable law.

RESTRICTIONS ON OWNERSHIP AND TRANSFER OF SHARES

    As  indicated above, the  ownership and transfer of  shares of COMSAT Common
Stock and  COMSAT  Preferred Stock  are  subject  to a  number  of  limitations,
including  the  following: (i)  not more  than  20% of  the aggregate  number of
outstanding shares of  COMSAT Common Stock  (held by persons  other than  Common
Carriers) and of COMSAT Preferred Stock may be held by Alien Persons (as defined
below), and (ii) not more than 10% of the aggregate number of outstanding shares
of  COMSAT Common Stock and of COMSAT Preferred Stock may be held by any person,
syndicate or affiliated group of persons (other than a Common Carrier).  Subject
to  these limitations  (as more  fully described below),  a holder  of shares of
COMSAT Common Stock may at any time transfer, sell or otherwise dispose of  such
shares  to any person to whom shares of either series of COMSAT Common Stock may
be issued,  and, upon  surrender  of the  share  certificate for  transfer,  the
transferee will receive a certificate, representing the same number of shares as
the surrendered certificate, for shares of the appropriate series.

    For  purposes  of the  limitation described  above,  "Alien Person"  means a
person who is, as to  the United States: (i) an  alien or the representative  of
any  alien; (ii)  a foreign  government or  the representative  thereof; (iii) a
corporation  organized  under  the  laws  of  any  foreign  government;  (iv)  a
corporation  of which any officer or director is  an alien or of which more than
one-fifth of the capital stock  is owned of record or  voted by aliens or  their
representatives  or by a foreign government  or representative thereof or by any
corporation  organized  under  the  laws  of  a  foreign  country;  or  (v)  any
corporation  directly or indirectly controlled by any other corporation of which
any officer or more  than one-fourth of  the directors are  aliens, or of  which
more than one-fourth of the capital stock is owned of record or voted by aliens,
their  representatives, or by a foreign government or representative thereof, or
by any corporation organized under the laws of a foreign country.

    The Satellite Act provides that  the maximum aggregate percentage of  COMSAT
Common  Stock  and COMSAT  Preferred Stock  that may  be held  by any  person or
syndicate or affiliated group of persons (other than a Common Carrier) shall not
exceed 10%; the COMSAT Articles provide that such percentage shall be determined
from time to time by the COMSAT Board  (but, in any event, shall not be  greater
than  10%). Pursuant to authority contained in  the Satellite Act and the COMSAT
Articles, the  COMSAT Board  has  determined by  resolution that  the  aggregate
number of shares of COMSAT Common Stock and COMSAT Preferred Stock owned or held
by  any person or  syndicate or affiliated  group of such  persons (other than a
Common Carrier)  may  not  at  any  time exceed  10%  of  the  total  number  of
outstanding  shares of  COMSAT capital stock,  but that no  person, syndicate or
affiliated group of such persons (other  than a Common Carrier) may vote  shares
held  in excess of five percent of the aggregate number of outstanding shares of
COMSAT capital stock. Notice of a determination by the COMSAT Board changing the
maximum percentage must  be mailed to  each holder of  record of COMSAT  capital
stock not less than 10 days before the effective date of such determination. Any
reduction  from the maximum will  not apply to the  ownership of shares acquired
before the effective date of any such determination.

                                       42
<PAGE>
    Certain  other limitations apply to the  ownership and holding of shares by,
and the  transfer of  shares by  and  to, Common  Carriers. See  "--  Provisions
Pertaining to Common Carriers".

    The  COMSAT Board is authorized to  establish procedures with respect to the
issuance  or  transfer  of  shares  of  COMSAT  capital  stock  to  enforce  the
limitations  referred  to  above.  Procedures established  by  the  COMSAT Board
require that, in  connection with  each issuance or  transfer of  shares on  the
books  of COMSAT,  the transferee  complete an  application for  transfer of the
shares.  Such  application   calls  for  information   about  the   transferee's
citizenship  status and relationship with Common  Carriers. The COMSAT Board may
deem certain  transferees automatically  to have  a particular  status, such  as
Series  I domestic or Series  I foreign, without requiring  the completion of an
application with respect to each transfer.

    Neither the  Satellite Act  nor the  COMSAT Articles  define the  respective
rights  of the  seller and  purchaser of shares  of COMSAT  capital stock where,
because of the restrictions  on the ownership and  transfer of such shares,  the
purchaser  is not entitled to  have the shares transferred to  him or her on the
books of COMSAT. The  respective rights of  the seller and  purchaser in such  a
case  would be  determined under  the law  applicable to  such sale.  The COMSAT
Articles provide, however, that nothing  in the provisions thereof limiting  the
ownership  and transfer  of shares  of COMSAT capital  stock shall  be deemed to
affect the right of the purchaser in such a case to transfer his or her interest
in the shares to any person who,  under the provisions of the Satellite Act  and
the COMSAT Articles, lawfully may acquire such interest.

    At  the close of business on March 31, 1995, to COMSAT's knowledge, based on
information provided  by COMSAT's  registrar and  transfer agent,  approximately
0.3%  of the  outstanding Series I  shares were owned  by or for  the account of
Alien Persons. Based on the number of  Series I shares outstanding on March  31,
1995,  the alien ownership limitation would  allow a maximum of 9,424,449 shares
of COMSAT Common Stock to be owned by Alien Persons.

PROVISIONS PERTAINING TO COMMON CARRIERS

    Shares of COMSAT  Common Stock  held by Authorized  Carriers are  designated
Series  II shares.  Except for an  Authorized Carrier, shares  of COMSAT capital
stock may not be owned or held,  directly or indirectly, by any Common  Carrier,
or  by a subsidiary or  affiliate of any Common  Carrier, nor may COMSAT capital
stock be  owned or  held  by a  trustee,  director, or  officer  of any  of  the
foregoing,  unless (a) such person is serving at the request of COMSAT or one of
its subsidiaries as a trustee, director or officer of a Common Carrier, or of  a
subsidiary  or affiliate of  such a carrier,  in which COMSAT  or its subsidiary
owns stock or is a creditor or  (b)(i) such person individually is not a  Common
Carrier;  (ii) such  shares are  owned by  such person  free from  any direct or
indirect control of a Common Carrier or of a subsidiary or affiliated company of
a Common  Carrier; and  (iii) such  person is  authorized by  the FCC  to  serve
concurrently  as  a  trustee or  director  of  such Common  Carrier  or  of such
subsidiary or  affiliated company  of a  Common  Carrier and  as a  director  of
COMSAT.  The aggregate number  of shares of  COMSAT Common Stock  owned or held,
directly or indirectly, by Authorized Carriers may not at any time exceed 50% of
the total number  of shares of  COMSAT Common Stock  issued and outstanding.  No
Authorized  Carrier or affiliated group of such carriers may sell or transfer to
persons other than Authorized Carriers shares of COMSAT Common Stock  totalling,
in any consecutive 12-month period, more than two percent of the greatest number
of  Series II  shares issued  and outstanding  at any  time during  such period,
except pursuant to a general public  offering or in conformity with  regulations
adopted  by the COMSAT Board  to encourage the widest  distribution of shares of
COMSAT Common  Stock  to  the  American public.  The  FCC  is  authorized,  upon
application  by any Authorized  Carrier and after notice  and hearing, to compel
any other  Authorized Carrier  which  owns shares  of  COMSAT capital  stock  to
transfer to the applicant, for fair and reasonable consideration, such number of
shares  as the FCC determines will advance  the public interest and the purposes
of the  Satellite Act.  Common Carriers  may not  own or  hold COMSAT  Preferred
Stock.

                                       43
<PAGE>
VOTING RIGHTS; ELECTION OF DIRECTORS

    If  COMSAT Preferred Stock  is issued, except in  the election of directors,
the holders  thereof will  be entitled  to one  vote per  share on  each  matter
submitted  to a vote at a meeting of shareholders. In the election of directors,
shares of COMSAT Preferred Stock would be treated in the same manner as Series I
shares, as described below.

    Except for the election of directors,  each share of COMSAT Common Stock  is
entitled  to  one vote  on  each matter  submitted  to a  vote  at a  meeting of
shareholders. In certain  cases, the District  of Columbia Business  Corporation
Act  would require a proposition  to receive the approval  of the holders of the
COMSAT Common Stock and the COMSAT Preferred Stock voting separately. Such cases
include certain amendments  to the COMSAT  Articles, mergers or  consolidations,
and the sale of all or substantially all of the assets of COMSAT. In such cases,
the  holders of  COMSAT Preferred  Stock could  prevent such  matters from being
approved, even if approved by the holders of COMSAT Common Stock.

    The Satellite  Act  provides that  the  COMSAT  Board shall  consist  of  15
directors,  of whom  three shall  be appointed  by the  President of  the United
States with  the  advice  and consent  of  the  United States  Senate,  and  the
remaining  12 shall be elected by the shareholders. Six of such directors are to
be elected by holders of Series I shares and six by holders of Series II shares.
However, the Satellite Act provides that if, as of the record date for an annual
meeting of  shareholders, the  number of  Series II  shares held  by  Authorized
Carriers  is  less than  45%  of the  total number  of  shares of  capital stock
outstanding, the number of directors holders of Series II shares are entitled to
elect will decrease and the number of  directors holders of Series I shares  are
entitled  to elect ("Series  I directors") will increase  in accordance with the
following table:

<TABLE>
<CAPTION>
   WHEN PROPORTION OF
    SHARES OF ISSUED                          THE NUMBER OF            AND THE NUMBER OF
     AND OUTSTANDING                         DIRECTORS WHICH      DIRECTORS WHICH HOLDERS OF
  COMSAT CAPITAL STOCK                         HOLDERS OF             SERIES I SHARES AND
    THAT IS OWNED BY                        SERIES II SHARES        COMSAT PREFERRED STOCK
   AUTHORIZED CARRIERS        BUT NOT        ARE ENTITLED TO            ARE ENTITLED TO
      IS LESS THAN:         LESS THAN:       ELECT SHALL BE:            ELECT SHALL BE:
- - -------------------------  -------------  ---------------------  -----------------------------
<S>                        <C>            <C>                    <C>
              45%                  40%                  5                          7
              40%                  35%                  4                          8
              35%                  25%                  3                          9
              25%                  15%                  2                         10
              15%                   8%                  1                         11
               8%               --                      0                         12
</TABLE>

    When Authorized Carriers own  less than 8% of  the shares of COMSAT  capital
stock  (as is currently the case), all shareholders vote together for directors,
and all directors are considered Series I directors. The Satellite Act makes  no
provision  for adjustment of Series I  and Series II directorships when, between
annual meetings, a change in the relative holdings of Series I shares and Series
II shares of COMSAT Common Stock and shares of COMSAT Preferred Stock may occur.

    In voting  for  directors,  the  Satellite Act  provides  that  each  COMSAT
shareholder  shall have cumulative  voting rights. Under  cumulative voting, the
holder may cast a number of votes equal to the number of shares held  multiplied
by  the total number of directors  to be elected and may  cast all of such votes
for a  single  candidate  or may  distribute  such  votes among  any  number  of
candidates to be elected. The Satellite Act restricts the voting power of Common
Carriers  by  preventing any  one  such carrier  from  electing more  than three
directors and all Common Carriers in  the aggregate from electing more than  six
directors,  unless, as is  currently the case, all  Common Carriers together own
less than 8% of all outstanding shares  of COMSAT capital stock. In such  event,
all  Common Carriers vote together with the  other shareholders for the Series I
directors.

    No share may be voted on any matter at a meeting of shareholders if, at  the
time  of such meeting, the share is owned  or held in violation of the Satellite
Act or any regulation promulgated thereunder

                                       44
<PAGE>
or in violation of the COMSAT Articles  or any determination made by the  COMSAT
Board thereunder. The COMSAT Board has determined, pursuant to authority granted
in  the COMSAT Articles, that  no person, syndicate or  affiliated group of such
persons (other than a Common  Carrier) may vote shares held  in excess of 5%  of
the  aggregate number of outstanding shares of COMSAT capital stock. COMSAT may,
in accordance  with resolutions  adopted by  the COMSAT  Board, require  that  a
holder  of shares furnish appropriate information in this connection when voting
such shares.

    All of the above provisions will apply to shares of COMSAT Common Stock that
may be  issued  upon conversion  of  the  Convertible Preferred  Shares  or  the
Convertible Junior Subordinated Debentures.

OTHER

    Under the provisions of the Satellite Act, COMSAT is authorized to issue, in
addition to shares of COMSAT Common Stock and COMSAT Preferred Stock, non-voting
securities,  bonds, debentures and other certificates  of indebtedness as it may
determine. The Satellite  Act requires FCC  approval to issue  shares of  COMSAT
capital stock, as well as for any borrowing of funds by COMSAT or any assumption
by it of any obligation in respect of the securities of any other person. COMSAT
is  currently  subject to  an  FCC-approved Capitalization  Plan  which includes
parameters requiring  that  COMSAT  maintain  (i)  a  long-term  debt  to  total
capitalization ratio of not greater than 45%, (ii) an interest coverage ratio of
2.3  to  1, and  (iii)  not more  than  $200 million  in  short-term borrowings.
Pursuant to  the  Capitalization  Plan,  COMSAT is  permitted  to  issue  equity
securities  upon two days' notice to the FCC  so long as COMSAT is in compliance
with such parameters.

    The transfer agent, registrar and  dividend disbursing agent for the  COMSAT
Common Stock is The Bank of New York.

                             UNITED STATES TAXATION

GENERAL

    This  section  is a  summary  of certain  United  States federal  income tax
considerations that may  be relevant  to prospective  purchasers of  Convertible
Preferred Securities and represents the opinion of Crowell & Moring, special tax
counsel to COMSAT and COMSAT Capital II, insofar as it relates to matters of law
and  legal conclusions.  This section  is based  upon current  provisions of the
Internal Revenue Code of  1986, as amended (the  "Code"), existing and  proposed
regulations  thereunder and current administrative  rulings and court decisions,
all  of  which  are  subject  to  change.  Subsequent  changes  may  cause   tax
consequences  to  vary  substantially  from  the  consequences  described below.
Moreover, the transactions described in this Prospectus raise certain novel  tax
issues  which  have not  been ruled  on by  the courts  or the  Internal Revenue
Service (the  "IRS") in  similar transactions.  As  a result,  there can  be  no
assurance  that the IRS  will not audit  these transactions and,  if it does so,
that the IRS will agree with the conclusions set forth below.

    No attempt  has been  made in  the following  discussion to  comment on  all
United  States federal  income tax  matters affecting  purchasers of Convertible
Preferred Securities. Moreover, the discussion focuses on holders of Convertible
Preferred Securities  who are  individual citizens  or residents  of the  United
States,  who  purchase Convertible  Preferred Securities  at original  issue for
their initial offering price and  who hold the Convertible Preferred  Securities
as  a capital asset, and has  only limited application to corporations, estates,
trusts, non-resident aliens or  taxpayers having a taxable  year other than  the
calendar  year. Accordingly, each prospective purchaser of Convertible Preferred
Securities should consult, and should depend on,  his or her own tax advisor  in
analyzing  the  federal,  state,  local  and  foreign  tax  consequences  of the
purchase, ownership or disposition of Convertible Preferred Securities.

                                       45
<PAGE>
TAX CLASSIFICATION

    Crowell &  Moring is  of the  opinion that  (i) COMSAT  Capital II  will  be
classified  as  a  partnership for  federal  income  tax purposes  and  (ii) the
Convertible Junior Subordinated  Debentures will be  classified as  indebtedness
for  federal income tax purposes,  although no assurances can  be made in either
regard. The following discussion assumes such classifications.

INCOME FROM CONVERTIBLE PREFERRED SECURITIES

    Each   holder   of   Convertible   Preferred   Securities   (a    "Preferred
Securityholder")  will  be required  to include  in  gross income  the Preferred
Securityholder's distributive share of the net  income of COMSAT Capital II.  If
COMSAT  Capital II is  merged into a trust  that is treated  as a grantor trust,
each Preferred Securityholder will  be treated as  owning directly an  allocable
portion  of  the  Convertible  Junior  Subordinated  Debentures  and  as earning
directly the income  derived therefrom.  In either  case, such  income will  not
exceed  for  any  calendar  month the  dividends  received  on  such Convertible
Preferred Securities, except in limited  circumstances as described below  under
"Original  Issue Discount" and "Potential Extension of Interest Payment Period".
Any amount  so  included  in  a Preferred  Securityholder's  gross  income  will
increase  its tax basis in the  Convertible Preferred Securities, and the amount
of nonliquidating distributions  of cash  by COMSAT  Capital II  to a  Preferred
Securityholder  will  reduce such  Preferred Securityholder's  tax basis  in the
Convertible Preferred Securities (but not below zero). No portion of such income
will be eligible for the dividends received deduction.

ORIGINAL ISSUE DISCOUNT

    Under Treasury Regulations, the stated interest payments on the  Convertible
Junior  Subordinated  Debentures will  be treated  as "original  issue discount"
(sometimes herein referred to for convenience as interest) because of the option
that COMSAT  has,  under  the  terms  of  the  Convertible  Junior  Subordinated
Debentures,  to defer  interest payments  for up to  60 months.  Under the Code,
holders of  debt with  original issue  discount must  include that  discount  in
income  on an economic accrual basis and before the receipt of cash attributable
to the interest  regardless of  their method of  tax accounting.  Except to  the
extent   COMSAT   exercises  its   option  to   defer  interest   payments,  the
characterization of the stated interest  on the Convertible Junior  Subordinated
Debentures  as original issue discount  will not affect the  timing or amount of
income reportable  by  Preferred Securityholders.  In  the event  that  interest
payments are deferred, COMSAT Capital II will continue to accrue income equal to
the  amount of the interest payment due at the end of the Extension Period on an
economic accrual basis over the length of the Extension Period.

    Accrued  income  will  be  allocated,  but  not  distributed,  to  Preferred
Securityholders  of record on  the Business Day  preceding the last  day of each
calendar month. As  a result, owners  of Convertible Preferred  Securities on  a
record  date during an Extension Period will include interest in gross income in
advance of  the receipt  of  cash, and  any  such Preferred  Securityholder  who
disposes  of Convertible Preferred  Securities prior to the  record date for the
payment of dividends following such Extension Period will include such Preferred
Securityholder's allocable share of such interest  in gross income but will  not
receive any cash related thereto.

    Holders  of  Convertible  Junior  Subordinated  Debentures  received  upon a
liquidation of  COMSAT  Capital  II or  deemed  to  be owned  by  the  Preferred
Securityholders upon merger of COMSAT Capital II into a trust that is taxed as a
grantor  trust,  will  include  in income  interest  on  the  Convertible Junior
Subordinated Debentures as  the interest  accrues (regardless  of the  Preferred
Securityholder's  method of accounting), and thus  will also recognize income in
advance of the receipt of cash.

DISPOSITION OF CONVERTIBLE PREFERRED SECURITIES

    Gain or  loss  will  be  recognized  on  a  sale  of  Convertible  Preferred
Securities, including a redemption for cash, equal to the difference between the
amount realized and the Preferred Securityholder's tax basis for the Convertible
Preferred Securities sold. Gain or loss recognized by a Preferred Securityholder
on  the sale or exchange of a  Convertible Preferred Security held for more than
one year will generally be taxable as long-term capital gain or loss.

                                       46
<PAGE>
    The adjusted tax  basis of  the Convertible Preferred  Securities sold  will
equal  the amount  paid for the  Convertible Preferred  Securities, plus accrued
original issue discount, if any, as described herein allocated to the holder  of
such  Convertible Preferred  Securities and reduced  by any  cash distributed to
such Preferred Securityholder by COMSAT  Capital II. A Preferred  Securityholder
acquiring  Convertible Preferred Securities at  different prices may be required
to maintain  a single  aggregate  adjusted tax  basis in  Convertible  Preferred
Securities,  and,  upon sale  or other  disposition of  some of  the Convertible
Preferred Securities, allocate a pro rata portion of such aggregate tax basis to
the Convertible Preferred  Securities sold (rather  than maintaining a  separate
tax  basis in each Convertible Preferred Security for purposes of computing gain
or loss on a sale of such Convertible Preferred Security).

EXCHANGE OF CONVERTIBLE PREFERRED SECURITIES FOR COMSAT COMMON STOCK

    A Preferred  Securityholder  should not  recognize  gain or  loss  upon  the
exchange,  through the Conversion Agent, of Convertible Preferred Securities for
a proportionate share of the Convertible Junior Subordinated Debentures held  by
COMSAT  Capital II. Under a  change in law or  a change in legal interpretation,
however, the exchange  could be a  taxable event to  holders of the  Convertible
Preferred  Securities. In the judgment of Crowell & Moring, the series of events
which would result in the recognition of taxable gain or loss by holders of  the
Convertible  Preferred Securities by reason of such an exchange is not likely to
occur.  There  can  be  no  assurance  in  this  regard,  however.  A  Preferred
Securityholder will in any event include in income interest accrued prior to the
exchange.

    A  Preferred  Securityholder  should not  recognize  gain or  loss  upon the
conversion, through  the Conversion  Agent, of  Convertible Junior  Subordinated
Debentures  into COMSAT Common Stock.  A Preferred Securityholder will recognize
gain, however, upon the receipt of cash in lieu of a fractional share of  COMSAT
Common   Stock  equal  to  the  amount  of  cash  received  less  the  Preferred
Securityholder's   tax   basis   in   such   fractional   share.   A   Preferred
Securityholder's tax basis in the COMSAT Common Stock received upon exchange and
conversion should generally be equal to the Preferred Securityholder's tax basis
in  the Convertible Preferred  Securities delivered to  the Conversion Agent for
exchange less the  basis allocated  to any fractional  share for  which cash  is
received  and a Preferred  Securityholder's holding period  in the COMSAT Common
Stock received upon exchange and conversion  should generally begin on the  date
the  Preferred  Securityholder  acquired  the  Convertible  Preferred Securities
delivered to the  Conversion Agent for  exchange, except in  the event that  the
exchange is a taxable event as described above.

ADJUSTMENT OF CONVERSION PRICE

    Treasury  Regulations promulgated under section 305  of the Code would treat
COMSAT Capital II (and,  thus, Preferred Securityholders)  as having received  a
constructive  distribution from COMSAT in the  event the conversion ratio of the
Convertible Junior Subordinated Debentures were adjusted  if (i) as a result  of
such  adjustment, the proportionate interest of  COMSAT Capital II in the assets
or earnings and profits of COMSAT were increased and (ii) the adjustment was not
made pursuant to a bona fide, reasonable antidilution formula. An adjustment  in
the  conversion ratio would not be considered made pursuant to such a formula if
the adjustment was  made to  compensate for certain  taxable distributions  with
respect  to the stock into which  the Convertible Junior Subordinated Debentures
are  convertible.  Thus,  under  certain  circumstances,  a  reduction  in   the
conversion price for the Convertible Junior Subordinated Debentures is likely to
be  taxable to COMSAT Capital II  as a dividend to the  extent of the current or
accumulated earnings and profits of COMSAT. The Preferred Securityholders  would
be  required to include  their allocable share of  such constructive dividend in
gross income but  will not receive  any cash related  thereto. In addition,  the
failure  to  fully  adjust  the  conversion  price  of  the  Convertible  Junior
Subordinated Debentures to reflect distributions of stock dividends with respect
to the COMSAT Common Stock  may result in a taxable  dividend to the holders  of
COMSAT Common Stock.

                                       47
<PAGE>
RECEIPT OF CONVERTIBLE JUNIOR SUBORDINATED DEBENTURES UPON LIQUIDATION OR MERGER
OF COMSAT
 CAPITAL II

    Under  certain circumstances, as described under the caption "Description of
the Convertible Preferred Securities  -- Tax Event  or Investment Company  Event
Redemption  or Distribution", Convertible Junior  Subordinated Debentures may be
distributed  to  the  holders  of   the  Convertible  Preferred  Securities   in
liquidation of COMSAT Capital II. Under current United States federal income tax
law,  such a  distribution would  be treated as  a non-taxable  exchange to each
holder of Convertible  Preferred Securities and  would result in  the holder  of
Convertible  Preferred  Securities  receiving  an  aggregate  tax  basis  in the
Convertible Junior Subordinated Debentures equal to such holder's aggregate  tax
basis  in its Convertible Preferred Securities. A holder's holding period in the
Convertible Junior Subordinated Debentures so received in liquidation of  COMSAT
Capital  II  would  include  the  period  for  which  the  Convertible Preferred
Securities were held  by such holder.  In addition, a  merger, consolidation  or
amalgamation  of COMSAT  Capital II into  a trust  that is treated  as a grantor
trust would be treated in the same  manner as a distribution of the  Convertible
Junior  Subordinated  Debentures to  the  holders of  the  Convertible Preferred
Securities in liquidation  of COMSAT Capital  II followed by  a contribution  of
such  Convertible Junior Subordinated  Debentures to the  grantor trust. Under a
change in  law, a  change in  legal interpretation  or the  other  circumstances
giving  rise  to  a Tax  Event  or  an Investment  Company  Event,  however, the
dissolution could be  a taxable event  to holders of  the Convertible  Preferred
Securities.  In the judgment of special tax counsel to COMSAT and COMSAT Capital
II, the series of events which would  result in the recognition of taxable  gain
or  loss by  holders of  the Convertible  Preferred Securities,  by reason  of a
dissolution of  COMSAT Capital  II, is  not likely  to occur.  There can  be  no
assurance in this regard, however.

TAXATION OF HOLDERS OF GRANTOR TRUST INTERESTS

    If  COMSAT Capital II is merged into a trust treated as a grantor trust, the
tax consequences of holding Successor Securities will differ in certain respects
from the  tax  consequences  of holding  Convertible  Preferred  Securities.  In
general,  holders of Successor  Securities will be required  to include in gross
income the income of  the trust as  such income accrues to  the trust. A  holder
that  includes amounts  in income  in advance  of the  receipt of  cash from the
grantor trust may not receive  the cash from the  grantor trust related to  such
income  if such  holder disposes of  its Successor Securities  before the record
date with  respect to  payment of  such amounts.  A holder's  tax basis  in  the
Successor  Securities will be  increased by the  amount of any  such accrued but
unpaid income.

COMSAT CAPITAL II INFORMATION RETURNS AND AUDIT PROCEDURES

    COMSAT, as  the General  Partner in  COMSAT Capital  II, will  furnish  each
Preferred  Securityholder  with  a Schedule  K-1  each year  setting  forth such
Preferred Securityholder's  allocable share  of income  for the  prior  calendar
year. The Limited Partnership Agreement requires COMSAT to furnish such Schedule
K-1 as soon as practicable following the end of the year, but in any event prior
to  March 31. In  the event that COMSAT  Capital II is replaced  with a trust as
previously described herein, investors will receive for tax reporting purposes a
Form 1099 instead of a Form K-1.

    Any person  who holds  Convertible  Preferred Securities  as a  nominee  for
another person is required to furnish to COMSAT Capital II (a) the name, address
and  taxpayer identification number of the beneficial owner and the nominee; (b)
information as to whether  the beneficial owner  is (i) a person  that is not  a
United  States person, (ii) a  foreign government, an international organization
or any wholly-owned  agency or instrumentality  of either of  the foregoing,  or
(iii)  a  tax-exempt  entity;  (c) the  amount  and  description  of Convertible
Preferred Securities held, acquired or transferred for the beneficial owner; and
(d) certain information including the dates of acquisitions and transfers, means
of acquisitions and transfers,  and acquisition cost for  purchases, as well  as
the  amount of net  proceeds from sales.  The nominee is  required to supply the
beneficial owners  of  Convertible  Preferred Securities  with  the  information
furnished  to COMSAT Capital II. Brokers and financial institutions are required
to furnish  additional information,  including whether  they are  United  States
persons and

                                       48
<PAGE>
certain  information on Convertible  Preferred Securities they  acquire, hold or
transfer for their own accounts. A penalty  of $50 per failure (up to a  maximum
of $100,000 per calendar year) is imposed by the Code for failure to report such
information.

    The  General Partner,  as the tax  matters partner, will  be responsible for
representing the Preferred Securityholders in any dispute with the IRS. The Code
provides for administrative examination of  a partnership as if the  partnership
were a separate and distinct taxpayer. Generally, the statute of limitations for
partnership  items does  not expire  before three years  after the  later of the
filing or the last date  for filing of the  partnership tax return (Form  1065),
determined without regard to extensions. The General Partner, as the tax matters
partner,  will have authority to extend  the statute of limitations with respect
to partnership items  for the Preferred  Securityholders without their  consent.
Any  adverse determination following an audit of the return of COMSAT Capital II
by the  appropriate taxing  authorities could  result in  an adjustment  of  the
returns  of the Preferred  Securityholders, and, under  certain circumstances, a
Preferred Securityholder may be precluded from separately litigating a  proposed
adjustment  to the items of the partnership.  An adjustment could also result in
an audit of  a Preferred Securityholder's  return and adjustments  of items  not
related to the income and losses of COMSAT Capital II.

POTENTIAL EXTENSION OF INTEREST PAYMENT PERIOD

    Under  the Indenture, COMSAT has  the right to extend  from time to time the
interest payment period on the  Convertible Junior Subordinated Debentures to  a
period  not  exceeding 60  consecutive months.  In the  event that  the interest
payment period is  extended, COMSAT Capital  II will continue  to accrue  income
equal  to the  amount of the  interest payment due  at the end  of the Extension
Period, on an economic basis  over the length of  the Extension Period. See  "--
Original Issue Discount".

UNITED STATES ALIEN HOLDERS

    For  purposes  of this  discussion, a  "United States  Alien Holder"  is any
holder who or  which is (i)  a nonresident  alien individual or  (ii) a  foreign
corporation,  partnership  or estate  or trust,  in either  case not  subject to
United States  federal  income  tax on  a  net  income basis  in  respect  of  a
Convertible  Preferred Security. This discussion is without regard to any income
tax treaty that may be applicable.

    Under  current  United  States  federal  income  tax  law,  subject  to  the
discussion below with respect to backup withholding:

        (i)  Payments by COMSAT  Capital II or  any of its  paying agents to any
    holder of a Convertible Preferred Security  who or which is a United  States
    Alien  Holder will not  be subject to United  States federal withholding tax
    provided that (a) the beneficial owner of the Convertible Preferred Security
    does not actually or  constructively own 10% or  more of the total  combined
    voting power of all classes of capital stock of COMSAT entitled to vote, (b)
    the  beneficial  owner  of  the  Convertible  Preferred  Security  is  not a
    controlled foreign  corporation  that is  related  to COMSAT  through  stock
    ownership  and  (c)  either  (x) the  beneficial  owner  of  the Convertible
    Preferred Security certifies to COMSAT Capital II or its agent (generally on
    Form W-8 or a substitute therefor), under penalties of perjury, that it is a
    United States Alien  Holder and  provides its name  and address  or (y)  the
    holder  of  the  Convertible  Preferred Security  is  a  securities clearing
    organization, bank  or other  financial  institution that  holds  customers'
    securities  in the  ordinary course of  its trade or  business (a "financial
    institution"), and such holder certifies to  COMSAT Capital II or its  agent
    under  penalties of perjury  that such statement has  been received from the
    beneficial owner by  it or  by a financial  institution between  it and  the
    beneficial  owner and furnishes COMSAT  Capital II or its  agent with a copy
    thereof;

        (ii) a United States  Alien Holder of  a Convertible Preferred  Security
    will  generally not be  subject to United States  federal withholding tax on
    any gain  realized  on the  sale  or  exchange of  a  Convertible  Preferred
    Security; and

       (iii)  a United States Alien Holder who is a nonresident alien individual
    present in the United  States for 183  days or more in  the taxable year  of
    sale and who either has a "tax home" in the

                                       49
<PAGE>
    United States or with respect to whom certain other requirements are met, is
    generally  subject to a 30% tax on the  amount by which his gross gains from
    the sale of capital assets derived from U.S. sources exceed his gross losses
    from such sales.

(An alien individual who  satisfies the "substantial  presence test" of  Section
7701(b)(3)  of the  Code, including  an alien  individual present  in the United
States for 183 days or  more in the calendar year,  will be taxed as a  resident
alien individual, and not as a nonresident alien individual.)

BACKUP WITHHOLDING AND INFORMATION REPORTING

    In  general, information  reporting requirements  will apply  to payments to
noncorporate United States holders  of the proceeds of  the sale of  Convertible
Preferred Securities within the United States and "backup withholding" at a rate
of  31% will apply to such payments if the United States holder fails to provide
an accurate taxpayer identification number.

    Payments of the proceeds from  the sale by a  United States Alien Holder  of
Convertible Preferred Securities made to or through a foreign office of a broker
generally  will not be  subject to information  reporting or backup withholding,
except that,  if the  broker is  a United  States person,  a controlled  foreign
corporation  for United States tax purposes, or  a foreign person 50% or more of
whose gross  income is  effectively  connected with  a  United States  trade  or
business  for a specified three-year period,  information reporting may apply to
such payments. Payments of the proceeds  from the sale by a noncorporate  holder
of  Convertible Preferred Securities to or through the United States office of a
broker is  subject  to information  reporting  and possible  backup  withholding
unless  the holder  or beneficial  owner certifies  as to  its non-United States
status or  otherwise establishes  an exemption  from information  reporting  and
backup withholding.

                                       50
<PAGE>
                                  UNDERWRITING

    Under  the terms and subject to  the conditions contained in an Underwriting
Agreement dated                    , 1995  (the "Underwriting  Agreement"),  the
Underwriters  named  below  (the  "Underwriters"),  for  whom  CS  First  Boston
Corporation,  Goldman,  Sachs  &  Co.  and  Smith  Barney  Inc.  are  acting  as
Representatives  (the "Representatives"), have severally  but not jointly agreed
to  purchase  from  COMSAT  Capital  II  the  following  respective  number   of
Convertible Preferred Securities:

<TABLE>
<CAPTION>
                                                                                    NUMBER OF
                                                                                   CONVERTIBLE
                                                                                    PREFERRED
                                   UNDERWRITER                                     SECURITIES
- - ---------------------------------------------------------------------------------  -----------
<S>                                                                                <C>
CS First Boston Corporation......................................................
Goldman, Sachs & Co..............................................................
Smith Barney Inc.................................................................

                                                                                   -----------
    Total........................................................................
                                                                                   -----------
                                                                                   -----------
</TABLE>

    The Underwriting Agreement provides that the obligations of the Underwriters
are  subject to certain  conditions precedent and that  the Underwriters will be
obligated to purchase all the Convertible Preferred Securities (other than those
covered by the over-allotment option described below) if any are purchased.  The
Underwriting  Agreement  provides  that,  in  the  event  of  a  default  by  an
Underwriter, in certain circumstances the purchase commitments of non-defaulting
Underwriters may be increased or the Underwriting Agreement may be terminated.

    COMSAT and COMSAT  Capital II have  granted to the  Underwriters an  option,
expiring  at  the close  of business  on the  30th  day after  the date  of this
Prospectus, to purchase up to       additional Convertible Preferred  Securities
at  the  initial  public  offering price  less  the  underwriting  discounts and
commissions, all as set forth on the cover page of this Prospectus. Such  option
may  be exercised only to  cover over-allotments in the  sale of the Convertible
Preferred Securities. To the extent  such option is exercised, each  Underwriter
will  become obligated, subject to certain conditions, to purchase approximately
the same percentage of  such additional Convertible  Preferred Securities as  it
was obligated to purchase pursuant to the Underwriting Agreement.

    COMSAT  and COMSAT Capital II have  been advised by the Representatives that
the Underwriters propose to  offer the Convertible  Preferred Securities to  the
public  initially at the  public offering price  set forth on  the cover page of
this Prospectus and through the Representatives to certain dealers at such price
less a concession of  $            per Convertible  Preferred Security, and  the
Underwriters and such dealers may allow a discount of $          per Convertible
Preferred  Security on sales to certain  other dealers. After the initial public
offering, the public offering price and  concession and discount to dealers  may
be changed by the Representatives.

    In  view  of the  fact  that the  proceeds of  the  sale of  the Convertible
Preferred Securities  will  be  used  by  COMSAT  Capital  II  to  purchase  the
Convertible  Junior Subordinated Debentures, the Underwriting Agreement provides
that COMSAT will pay as compensation to the Underwriters a commission of $   per
Convertible Preferred Security.

    COMSAT and COMSAT  Capital II have  agreed that they  will not offer,  sell,
contract  to sell, announce their intention to sell, pledge or otherwise dispose
of, directly or indirectly, or file with the Commission a registration statement
under the Securities Act  relating to (a) any  limited partnership interests  or
other  securities of  COMSAT Capital  II (other  than the  Convertible Preferred
Securities

                                       51
<PAGE>
offered hereby), (b) any preferred stock or any other securities of COMSAT which
are substantially similar to the Convertible Preferred Securities including  the
Guarantee,  or to the Convertible Junior Subordinated Debentures, (c) any shares
of COMSAT Common Stock or  any other capital stock of  COMSAT, or (d) any  other
securities  which  are convertible  into,  or exercisable  or  exchangeable for,
limited partnership interests in  or other securities of  COMSAT Capital II,  or
preferred  stock or such  substantially similar securities  of COMSAT, or COMSAT
Common Stock or other capital stock of COMSAT, in any such case for a period  of
90  days after the date of this Prospectus, without the prior written consent of
CS First Boston Corporation.  Such agreement will not  prevent the offer,  sale,
contract  to sell, or other disposition of  (i) the Preferred Securities, or the
related guarantee or  Junior Subordinated Debentures,  (ii) COMSAT Common  Stock
issued  or delivered  upon conversion or  exchange of  the Convertible Preferred
Securities or the Convertible  Subordinated Debentures, (iii) securities  issued
or  delivered upon conversion,  exchange or exercise of  any other securities of
COMSAT outstanding on  the date of  this Prospectus, (iv)  COMSAT capital  stock
issued  pursuant  to benefit  or incentive  plans  maintained for  its officers,
directors or employees, or pursuant to the COMSAT dividend reinvestment plan, or
(v) securities  issued  in  connection with  mergers,  acquisitions  or  similar
transactions.

    COMSAT  Capital  II and  COMSAT have  agreed  to indemnify  the Underwriters
against certain liabilities,  including civil liabilities  under the  Securities
Act, or contribute to payments which the Underwriters may be required to make in
respect thereof.

    Certain  of the Underwriters  engage in transactions with,  and from time to
time have performed services  for, COMSAT and its  subsidiaries in the  ordinary
course of business.

                          NOTICE TO CANADIAN RESIDENTS

RESALE RESTRICTIONS

    The  distribution of the Convertible Preferred Securities in Canada is being
made only on a private placement  basis exempt from the requirement that  COMSAT
and  COMSAT  Capital  II  prepare  and file  a  prospectus  with  the securities
regulatory authorities in  each province where  trades of Convertible  Preferred
Securities  are effected. Accordingly,  any resale of  the Convertible Preferred
Securities in Canada must be made in accordance with applicable securities  laws
which  will vary depending  on the relevant jurisdiction,  and which may require
resales to be made in accordance with available statutory exemptions or pursuant
to a  discretionary  exemption granted  by  the applicable  Canadian  securities
regulatory  authority. Purchasers are advised to  seek legal advice prior to any
resale of the Convertible Preferred Securities.

REPRESENTATIONS OF PURCHASERS

    Each purchaser of Convertible Preferred Securities in Canada who receives  a
purchase  confirmation will be deemed to  represent to COMSAT and COMSAT Capital
II and the dealer from whom such purchase confirmation is received that (i) such
purchaser is entitled  under applicable provincial  securities laws to  purchase
such  Convertible  Preferred  Securities  without the  benefit  of  a prospectus
qualified under such  securities laws,  (ii) where  required by  law, that  such
purchaser  is purchasing as principal and not as agent, and (iii) such purchaser
has reviewed the text above under "Resale Restrictions".

RIGHTS OF ACTION AND ENFORCEMENT

    The securities  being offered  are those  of a  foreign issuer  and  Ontario
purchasers  will  not  receive the  contractual  right of  action  prescribed by
section 32 of the  Regulation under the SECURITIES  ACT (Ontario). As a  result,
Ontario  purchasers must rely on other remedies that may be available, including
common law rights of action for damages or rescission or rights of action  under
the civil liability provisions of the U.S. federal securities laws.

    All  of the  issuer's directors  and officers as  well as  the experts named
herein may be located outside of Canada and, as a result, it may not be possible
for Ontario purchasers to effect service of process

                                       52
<PAGE>
within Canada upon the issuer or such  persons. All or a substantial portion  of
the  assets of the issuer and such persons may be located outside of Canada and,
as a result, it may not be possible to satisfy a judgment against the issuer  or
such  persons in  Canada or  to enforce a  judgment obtained  in Canadian courts
against such issuer or persons outside of Canada.

NOTICE TO BRITISH COLUMBIA RESIDENTS

    A purchaser of Convertible Preferred  Securities to whom the SECURITIES  ACT
(British  Columbia) applies is  advised that such purchaser  is required to file
with the British Columbia Securities Commission a report within ten days of  the
sale of any Convertible Preferred Securities acquired by such purchaser pursuant
to  this offering. Such report must be  in the form attached to British Columbia
Securities Commission Blanket Order BOR #88/5,  a copy of which may be  obtained
from  COMSAT.  Only one  such report  must  be filed  in respect  of Convertible
Preferred Securities acquired  on the same  date and under  the same  prospectus
exemption.

                                    EXPERTS

    The  consolidated financial  statements and the  related financial statement
schedules incorporated  in this  Prospectus by  reference from  COMSAT's  Annual
Report  on Form 10-K for  the year ended December 31,  1994 have been audited by
Deloitte & Touche LLP,  independent auditors, as stated  in their report  (which
includes  an  explanatory paragraph  referring to  the change  in its  method of
accounting for income  taxes), which  is incorporated herein  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.

                           VALIDITY OF THE SECURITIES

    The validity of the  Convertible Preferred Securities,  the validity of  the
Limited  Partnership Agreement and the formation  of COMSAT Capital II are being
passed upon by Crowell  & Moring, special counsel  to COMSAT and COMSAT  Capital
II.   The  validity  of  the  Guarantee,  the  Convertible  Junior  Subordinated
Debentures and the COMSAT Common Stock issuable upon exchange of the Convertible
Junior Subordinated Debentures will be passed  upon on behalf of COMSAT  Capital
II  and COMSAT  by Warren  Y. Zeger, Esq.,  Vice President,  General Counsel and
Secretary of COMSAT.  As of May     , 1995, Mr.  Zeger was the  record owner  of
      shares  of COMSAT Common Stock and had options to purchase       shares of
COMSAT Common Stock, of which options to purchase       shares were exercisable.
The validity  of  the  Convertible  Preferred  Securities,  the  Guarantee,  the
Convertible  Junior Subordinated Debentures and the  COMSAT Common Stock will be
passed upon for the Underwriters by Sullivan & Cromwell. Mr. Zeger will rely  on
Crowell  & Moring as to certain matters of Delaware law. Statements as to United
States taxation in  this Prospectus in  the second paragraph  under the  caption
"Risk   Factors  --  Tax  Event  or   Investment  Company  Event  Redemption  or
Distribution", and under the caption "United States Taxation", have been  passed
upon  for COMSAT and COMSAT Capital II  by Crowell & Moring, special tax counsel
to COMSAT and COMSAT Capital II, and are stated herein on their authority.

                                       53
<PAGE>
- - ------------------------------------------------
                                ------------------------------------------------

    NO  DEALER,  SALESPERSON OR  OTHER PERSON  HAS BEEN  AUTHORIZED TO  GIVE ANY
INFORMATION OR TO MAKE ANY REPRESENTATION NOT CONTAINED IN THIS PROSPECTUS  AND,
IF  GIVEN OR MADE, SUCH INFORMATION OR REPRESENTATION MUST NOT BE RELIED UPON AS
HAVING BEEN AUTHORIZED BY COMSAT OR  COMSAT CAPITAL II OR ANY UNDERWRITER.  THIS
PROSPECTUS DOES NOT CONSTITUTE AN OFFER TO SELL OR A SOLICITATION OF AN OFFER TO
BUY  ANY OF THE SECURITIES  OFFERED HEREBY IN ANY  JURISDICTION TO ANY PERSON TO
WHOM IT  IS  UNLAWFUL TO  MAKE  SUCH OFFER  IN  SUCH JURISDICTION.  NEITHER  THE
DELIVERY  OF  THIS  PROSPECTUS NOR  ANY  SALE  MADE HEREUNDER  SHALL,  UNDER ANY
CIRCUMSTANCES, CREATE ANY IMPLICATION THAT  THE INFORMATION CONTAINED HEREIN  IS
CORRECT  AS OF ANY TIME SUBSEQUENT TO THE  DATE HEREOF OR THAT THERE HAS BEEN NO
CHANGE IN THE AFFAIRS OF COMSAT OR COMSAT CAPITAL II SINCE SUCH DATE.

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

                               TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                    PAGE
                                                    -----
<S>                                              <C>
Available Information..........................           3
Incorporation of Certain Documents by
 Reference.....................................           3
Prospectus Summary.............................           4
Summary Financial Information of COMSAT........           9
Risk Factors...................................          10
COMSAT Capital II..............................          12
COMSAT Corporation.............................          12
Use of Proceeds................................          14
Capitalization of COMSAT.......................          15
Ratio of Earnings to Fixed Charges of COMSAT...          15
Market Prices of COMSAT Common Stock and
 Dividends.....................................          16
Description of the Convertible Preferred
 Securities....................................          17
Description of the Guarantee...................          30
Description of the Convertible Junior
 Subordinated Debentures.......................          33
Effect of Obligations Under the Convertible
 Junior Subordinated Debentures and the
 Guarantee.....................................          39
Description of COMSAT Capital Stock............          40
United States Taxation.........................          45
Underwriting...................................          51
Notice to Canadian Residents...................          52
Experts........................................          53
Validity of the Securities.....................          53
</TABLE>

                                ,000,000 SHIPS-SM-
                               COMSAT Capital II
                                  % Share-linked
                    Income Preferred Securities (SHIPS-SM-)
                            guaranteed to the extent
                            set forth herein by, and
                       convertible into Common Stock of,

                           [LOGO] COMSAT Corporation

                                   PROSPECTUS

                                CS First Boston
                              Goldman, Sachs & Co.

                               Smith Barney Inc.

- - ------------------------------------------------
                                ------------------------------------------------
<PAGE>
                                    PART II

                     INFORMATION NOT REQUIRED IN PROSPECTUS

ITEM 14.  OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION.

    The  following  table  sets  forth the  estimated  expenses  payable  by the
registrants  with  respect  to  the  offering  described  in  this  Registration
Statement:

<TABLE>
<S>                                                                <C>
Securities and Exchange Commission registration fee..............  $  68,966
NASD fees........................................................     10,500
NYSE fees........................................................           *
Organization fees................................................           *
Trustee's fees and expenses......................................           *
Printing and engraving...........................................           *
Legal fees and expenses..........................................           *
Accounting fees and expenses.....................................           *
Rating Agency fees...............................................           *
Blue sky fees and expenses (including legal).....................           *
Miscellaneous fees and expenses..................................           *
                                                                   ---------
Total............................................................  $        *
                                                                   ---------
                                                                   ---------
<FN>
- - --------------
*To be filed by amendment
</TABLE>

ITEM 15.  INDEMNIFICATION OF OFFICERS AND DIRECTORS.

    Reference  is made to the provisions of  Article III of COMSAT's Articles of
Incorporation filed as Exhibit 4(a)  to COMSAT's Registration Statement on  Form
S-3  (No. 33-51661) and the provisions of Article VIII of COMSAT's By-laws filed
as Exhibit  3(b) to  COMSAT's Annual  Report on  Form 10-K  for the  year  ended
December 31, 1994, which provisions are hereby incorporated by reference herein.

    Section  29-304  of  the  District  of  Columbia  Business  Corporations Act
provides a District of  Columbia corporation shall have  the power to  indemnify
any  and all of its directors or officers or former directors or officers or any
person who may have served  at its request as a  director or officer of  another
corporation  in  which it  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
directors  or officers or a  director or officer of  the corporation, or of such
other corporation, except in relation to  matters as to which any such  director
or  officer or former director  or officer or persons  shall be adjudged in such
action, suit or  proceeding to  be liable for  negligence or  misconduct in  the
performance  of duty. Such indemnification shall  not be deemed exclusive of any
other rights  to which  those  indemnified may  be  entitled, under  any  bylaw,
agreement, vote of stockholders, or otherwise.

    There  are in effect  directors' and officers'  liability insurance policies
which insure COMSAT's  directors and officers  against certain liabilities  that
they may incur in such capacities.

ITEM 16.  EXHIBITS.

    The exhibits listed below are listed according to the number assigned in the
table in Item 601 of Regulation S-K.

<TABLE>
<CAPTION>
 EXHIBIT NO.                                             DESCRIPTION OF EXHIBIT
- - --------------  --------------------------------------------------------------------------------------------------------
<C>             <S>
         1(a)   Form of Underwriting Agreement for Preferred Securities.*
         1(b)   Form of Underwriting Agreement for Convertible Preferred Securities.*
</TABLE>

                                      II-1
<PAGE>
<TABLE>
<CAPTION>
 EXHIBIT NO.                                             DESCRIPTION OF EXHIBIT
- - --------------  --------------------------------------------------------------------------------------------------------
<C>             <S>
         4(a)   Articles of Incorporation of COMSAT Corporation (composite copy; as amended through June 1, 1993)
                 (Incorporated by reference to Exhibit 4(a) to COMSAT Corporation's Registration Statement on Form S-3,
                 Commission File No. 33-51661).
         4(b)   By-laws of COMSAT Corporation (as amended through January 17, 1995) (Incorporated by reference to
                 Exhibit 3(b) to COMSAT Corporation's Annual Report on Form 10-K for the year ended December 31, 1994).
         4(c)   Form of Indenture between COMSAT Corporation and                   , as Trustee.*
         4(d)   Form of Supplemental Indenture (Junior Subordinated Debentures) between COMSAT Corporation and
                                   , as Trustee.*
         4(e)   Form of Amended and Restated Limited Partnership Agreement of COMSAT Capital I, L.P.*
         4(f)   Certificate of Limited Partnership of COMSAT Capital I, L.P.
         4(g)   Form of Junior Subordinated Debenture (See Exhibit 4(d)).
         4(h)   Form of Preferred Security (See Exhibit 4(e)).
         4(i)   Form of Supplemental Indenture (Convertible Junior Subordinated Debentures) between COMSAT Corporation
                 and                   , as Trustee.*
         4(j)   Form of Amended and Restated Limited Partnership Agreement of COMSAT Capital II, L.P.*
         4(k)   Certificate of Limited Partnership of COMSAT Capital II, L.P.
         4(l)   Form of Convertible Junior Subordinated Debenture (See Exhibit 4(i)).
         4(m)   Form of Convertible Preferred Security (See Exhibit 4(j)).
         4(n)   Form of Guarantee Agreement for Preferred Securities.*
         4(o)   Form of Guarantee Agreement for Convertible Preferred Securities.*
         4(p)   Form of COMSAT Series I Common Stock certificate (domestic).*
         4(q)   Form of COMSAT Series I Common Stock certificate (foreign).*
         5(a)   Opinion of Warren Y. Zeger, Vice President, General Counsel and Secretary of COMSAT Corporation, as to
                 the legality of certain securities to which this Registration Statement relates.*
         5(b)   Opinion of Crowell & Moring as to the legality of certain securities to which this Registration
                 Statement relates.*
         8      Opinion of Crowell & Moring, special tax counsel to the registrants, with respect to tax matters.*
        12      Statement re Ratio of Earnings to Fixed Charges.
        23(a)   Consent of Deloitte & Touche LLP.
        23(b)   Consent of Warren Y. Zeger (contained in Exhibit 5(a)).
        23(c)   Consent of Crowell & Moring (contained in Exhibit 5(b)).
        23(d)   Consent of Crowell & Moring (contained in Exhibit 8).
        24      Powers of Attorney.
</TABLE>

                                      II-2
<PAGE>
<TABLE>
<CAPTION>
 EXHIBIT NO.                                             DESCRIPTION OF EXHIBIT
- - --------------  --------------------------------------------------------------------------------------------------------
<C>             <S>
        25      Statement on Form T-1 of eligibility and qualification of                    under the Trust Indenture
                 Act of 1939.*
        99      Communications Satellite Act of 1962, as amended (Incorporated by reference to Exhibit 28(c) to COMSAT
                 Corporation's Registration Statement on Form S-4, Commission File No. 33-9966).
<FN>
- - --------------
* To be filed by amendment.
</TABLE>

ITEM 17.  UNDERTAKINGS.

    (a) The undersigned registrants hereby undertake:

        (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,  (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; notwithstanding the foregoing, any increase or decrease in volume
    of securities offered (if the total dollar value of securities offered would
    not exceed that which was registered) and any deviation from the low or high
    end of the estimated maximum offering range may be reflected in the form  of
    prospectus  filed with  the Commission  pursuant to  Rule 424(b)  if, in the
    aggregate, the changes  in volume  and price represent  no more  than a  20%
    change in the maximum aggregate offering price set forth in the "Calculation
    of  Registration  Fee" table  in the  effective registration  statement; and
    (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 the undertakings  set forth in clauses  (i) and (ii) above  do
    not  apply if  the information required  to be included  in a post-effective
    amendment by those clauses  is contained in periodic  reports filed with  or
    furnished to the Commission by either of the registrants pursuant to Section
    13  or 15(d) of the Securities Exchange Act of 1934 that are incorporated by
    reference in this registration statement;

        (2) That,  for  the  purpose  of determining  any  liability  under  the
    Securities  Act of 1933, 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.

    (b)  The  undersigned registrants  hereby  undertake that,  for  purposes of
determining any  liability under  the Securities  Act of  1933, each  filing  of
COMSAT's  annual report  pursuant to  Section 13(a)  or 15(d)  of the Securities
Exchange Act  of 1934  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.

    (h)  Insofar as indemnification for liabilities arising under the Securities
Act of 1933 may be permitted to directors, officers, and controlling persons  of
the  registrants  pursuant  to  the  foregoing  provisions,  or  otherwise,  the
registrants have 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 registrants of expenses
incurred or paid by a director, officer or controlling person of the registrants
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 registrants will, unless

                                      II-3
<PAGE>
in  the opinion  of their  counsel the  matter has  been settled  by controlling
precedent, submit to a  court of appropriate  jurisdiction the question  whether
such  indemnification by them is  against public policy as  expressed in the Act
and will be governed by the final adjudication of such issue.

    (i)  The undersigned registrants hereby undertake that:

        (1) For purposes of determining  any liability under the Securities  Act
    of  1933, the information omitted from the  form of prospectus filed as part
    of this registration statement in reliance upon Rule 430A and contained in a
    form of prospectus filed  by the registrants pursuant  to Rule 424(b)(1)  or
    (4)  or 497(h) under the  Securities Act shall be deemed  to be part of this
    registration statement as of the time it was declared effective.

        (2) For the purpose  of determining any  liability under the  Securities
    Act  of  1933,  each  post-effective  amendment  that  contains  a  form  of
    prospectus 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.

                                      II-4
<PAGE>
                                   SIGNATURES

    Pursuant  to  the  requirements  of  the  Securities  Act  of  1933,  COMSAT
Corporation certifies that it  has reasonable grounds to  believe that it  meets
all  of  the  requirements for  filing  on Form  S-3  and 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 2nd day
of June, 1995.

                                          COMSAT Corporation
                                          (Registrant)

                                          By   /s/ WARREN Y. ZEGER

                                            ------------------------------------
                                                  (Warren Y. Zeger, Vice
                                             President,
                                                 General Counsel and Secretary)

    Pursuant  to  the  requirements  of   the  Securities  Act  of  1933,   this
Registration  Statement  has  been  signed  by  the  following  persons  in  the
capacities indicated and by power of attorney on June 2, 1995.

                                          (1)  Principal executive officer

                                                /s/ BRUCE L. CROCKETT*
                                              ----------------------------------
                                                  (Bruce L. Crockett,
                                                 President and Chief Executive
                                              Officer)

                                          (2)  Principal financial and
                                               accounting officer

                                                /s/ ALLEN E. FLOWER*
                                              ----------------------------------
                                                  (Allen E. Flower, Acting
                                                 Chief Financial Officer and
                                              Controller)

                                          (3)  Board of Directors

                                                /s/ LUCY WILSON BENSON*
                                              ----------------------------------
                                                  (Lucy Wilson Benson, Director)

                                                /s/ EDWIN I. COLODNY*
                                              ----------------------------------
                                                  (Edwin I. Colodny, Director)

                                                /s/ BRUCE L. CROCKETT*
                                              ----------------------------------
                                                  (Bruce L. Crockett, Director)

                                                /s/ LAWRENCE S. EAGLEBURGER*
                                              ----------------------------------
                                                  (Lawrence S. Eagleburger,
                                               Director)

                                      II-5
<PAGE>
                                                /s/ NEAL B. FREEMAN*
                                               ---------------------------------
                                                  (Neal B. Freeman, Director)

                                                /s/ BARRY M. GOLDWATER*
                                              ----------------------------------
                                                  (Barry M. Goldwater, Director)

                                                /s/ ARTHUR HAUSPURG*
                                              ----------------------------------
                                                  (Arthur Hauspurg, Director)

                                                /s/ PETER S. KNIGHT*
                                              ----------------------------------
                                                  (Peter S. Knight, Director)

                                                /s/ MELVIN R. LAIRD*
                                              ----------------------------------
                                                  (Melvin R. Laird,
                                                  Chairman of the Board and
                                               Director)

                                                /s/ PETER W. LIKINS*
                                              ----------------------------------
                                                  (Peter W. Likins, Director)

                                              ----------------------------------
                                                  (Howard M. Love, Director)

                                                /s/ CHARLES T. MANATT*
                                              ----------------------------------
                                                  (Charles T. Manatt, Director)

                                                /s/ ROBERT G. SCHWARTZ*
                                              ----------------------------------
                                                  (Robert G. Schwartz, Director)

                                                /s/ C. J. SILAS*
                                              ----------------------------------
                                                  (C. J. Silas, Director)

                                                /s/ DOLORES D. WHARTON*
                                              ----------------------------------
                                                  (Dolores D. Wharton, Director)

*By: /s/ WARREN Y. ZEGER
    ----------------------------------
        (Warren Y. Zeger,
     Attorney-in-fact)
     --------------------------------------------------------------------

                                      II-6
<PAGE>
    Pursuant to the requirements of the  Securities Act of 1933, COMSAT  Capital
I, L.P. certifies that it has reasonable grounds to believe that it meets all of
the  requirements for filing on  Form S-3 and 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 2nd day of
June, 1995.

                                          COMSAT Capital I, L.P.
                                          (Registrant)
                                          By: COMSAT Corporation, General
                                          Partner

                                          By:   /s/ WARREN Y. ZEGER

                                             -----------------------------------
                                                   (Warren Y. Zeger, Vice
                                              President,
                                                  General Counsel and Secretary)

    Pursuant to the requirements of the  Securities Act of 1933, COMSAT  Capital
II,  L.P. certifies that it has reasonable  grounds to believe that it meets all
of the requirements for filing on Form S-3 and 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 2nd day of
June, 1995.

                                          COMSAT Capital II, L.P.
                                          (Registrant)
                                          By: COMSAT Corporation, General
                                          Partner

                                          By:   /s/ WARREN Y. ZEGER

                                             -----------------------------------
                                                   (Warren Y. Zeger, Vice
                                              President,
                                                   General Counsel and
                                              Secretary)

                                      II-7

<PAGE>

                                                           PAGE 1

                                State of Delaware

                        Office of the Secretary of State


     I, EDWARD J. FREEL, SECRETARY OF STATE OF THE STATE OF DELAWARE, DO HEREBY
CERTIFY THE ATTACHED IS A TRUE AND CORRECT COPY OF THE CERTIFICATE OF LIMITED
PARTNERSHIP OF "COMSAT CAPITAL I, L.P.", FILED IN THIS OFFICE ON THE
TWENTY-SECOND DAY OF MAY, A.D. 1995, AT 3 O'CLOCK P.M.


[Great Seal of the State of Delaware]


                              /s/ Edward J. Freel
                              ___________________________________
                              Edward J. Freel, Secretary of State

2509315  8100                      Authentication:  7513561
950112948                                    Date:  05-22-95

<PAGE>

                       CERTIFICATE OF LIMITED PARTNERSHIP

                                       OF

                             COMSAT CAPITAL I, L.P.

     The undersigned, desiring to form a limited partnership pursuant to the
Delaware Revised Uniform Limited Partnership Act, 6 Delaware Code, Chapter 17,
do hereby certify as follows:
     I.   The name of the limited partnership is COMSAT Capital
          I, L.P.
     II.  The address of the Partnership's registered office in
          the State of Delaware is Corporation Trust Center, 1209
          Orange Street, Wilmington, County of New Castle.  The
          name of the Partnership's registered agent for service
          of process in the State of Delaware at such address is
          The Corporation Trust Company.
     III. The name and mailing address of each general partner is
          as follows:
          Name                     Mailing Address
          ----                     ---------------
          COMSAT Corporation       6560 Rock Spring Drive
                                   Bethesda, MD  20817

     IN WITNESS WHEREOF, the undersigned has executed this Certificate of
Limited Partnership of COMSAT Capital I, L.P. as of May 22, 1995.

                                    General Partner

                                    COMSAT Corporation

                                        /s/ Bruce L. Crockett
                                    By:__________________________
                                       Name:  Bruce L. Crockett
                                       Title: President and Chief
                                                Executive Officer



<PAGE>
                                                           PAGE 1

                                State of Delaware

                        Office of the Secretary of State


     I, EDWARD J. FREEL, SECRETARY OF STATE OF THE STATE OF DELAWARE, DO HEREBY
CERTIFY THE ATTACHED IS A TRUE AND CORRECT COPY OF THE CERTIFICATE OF LIMITED
PARTNERSHIP OF "COMSAT CAPITAL II, L.P.", FILED IN THIS OFFICE ON THE
TWENTY-SECOND DAY OF MAY, A.D. 1995, AT 3 O'CLOCK P.M.


[Great Seal of the State of Delaware]


                              /s/ Edward J. Freel
                              ___________________________________
                              Edward J. Freel, Secretary of State

2509318  8100                      Authentication:  7513562
950112953                                    Date:  05-22-95

<PAGE>

                       CERTIFICATE OF LIMITED PARTNERSHIP

                                       OF

                             COMSAT CAPITAL II, L.P.

     The undersigned, desiring to form a limited partnership pursuant to the
Delaware Revised Uniform Limited Partnership Act, 6 Delaware Code, Chapter 17,
do hereby certify as follows:
      I.  The name of the limited partnership is COMSAT Capital
          II, L.P.
     II.  The address of the Partnership's registered office in
          the State of Delaware is Corporation Trust Center, 1209
          Orange Street, Wilmington, County of New Castle.  The
          name of the Partnership's registered agent for service
          of process in the State of Delaware at such address is
          The Corporation Trust Company.
     III. The name and mailing address of each general partner is
          as follows:
          Name                     Mailing Address
          ----                     ---------------
          COMSAT Corporation       6560 Rock Spring Drive
                                   Bethesda, MD  20817

     IN WITNESS WHEREOF, the undersigned has executed this Certificate of
Limited Partnership of COMSAT Capital II, L.P. as of May 22, 1995.

                                    General Partner

                                    COMSAT Corporation

                                        /s/ Bruce L. Crockett
                                    By:__________________________
                                       Name:  Bruce L. Crockett
                                       Title: President and Chief
                                                Executive Officer




<PAGE>
                                                                      EXHIBIT 12

                      COMSAT CORPORATION AND SUBSIDIARIES
               COMPUTATION OF RATIO OF EARNINGS TO FIXED CHARGES

                         (Dollar amounts in thousands)

<TABLE>
<CAPTION>
                                                  QUARTER ENDED
                                                    MARCH 31,                           YEAR ENDED DECEMBER 31,
                                               --------------------  -------------------------------------------------------------
                                                 1995       1994        1994         1993         1992         1991        1990
                                               ---------  ---------  -----------  -----------  -----------  -----------  ---------
<S>                                            <C>        <C>        <C>          <C>          <C>          <C>          <C>
Income (loss) from continuing operations
 before income taxes, extraordinary items and
 cumulative effect of accounting changes.....  $  22,911  $  31,959  $   127,321  $   137,661  $    83,263  $   118,566  $  (5,767)
Add (subtract):
  Interest on indebtedness (net of amount
   capitalized)..............................      8,875      6,152       25,278       23,684       26,311       19,931      7,339
  Other interest expense (1).................     --         --          --           --             1,263        3,195      3,074
  Portion of rents representative of the
   interest factor...........................        894      1,141        4,191        4,007        2,124        1,837      1,351
  Undistributed income of less-than-fifty
   percent owned investments.................       (322)      (535)      (1,340)      (1,541)         (64)         (35)    --
  Equity losses of less-than-fifty percent
   owned investments.........................        525         61          561          154          136          182     --
  Minority interest share of losses of
   majority-owned subsidiaries...............       (716)    --             (605)     --            (1,160)      (3,577)    (3,721)
  Amortization and write off of previously
   capitalized interest......................      6,011      5,985       24,134       21,132       20,035       20,821     16,594
                                               ---------  ---------  -----------  -----------  -----------  -----------  ---------
Income as adjusted...........................  $  38,178  $  44,763  $   179,540  $   185,097  $   131,908  $   160,920  $  18,870
                                               ---------  ---------  -----------  -----------  -----------  -----------  ---------
                                               ---------  ---------  -----------  -----------  -----------  -----------  ---------
Fixed charges:
  Interest on indebtedness...................  $  14,751  $  11,892  $    48,940  $    45,881  $    46,792  $    47,328  $  38,171
  Other interest expense (1).................     --         --          --           --             1,263        3,195      3,074
  Portion of rents representative of the
   interest factor...........................        894      1,141        4,191        4,007        2,124        1,837      1,351
                                               ---------  ---------  -----------  -----------  -----------  -----------  ---------
Total fixed charges..........................  $  15,645  $  13,033  $    53,131  $    49,888  $    50,179  $    52,360  $  42,596
                                               ---------  ---------  -----------  -----------  -----------  -----------  ---------
                                               ---------  ---------  -----------  -----------  -----------  -----------  ---------
RATIO OF EARNINGS TO FIXED CHARGES (2).......        2.4        3.4          3.4          3.7          2.6          3.1         (3)
<FN>
- - ------------------

(1)  Interest  expense of  majority-owned subsidiary  not consolidated  in 1990,
     1991 and the first half of 1992.

(2)  A portion  of  the securities  being  registered  will be  used  to  reduce
     outstanding  commercial  paper  of  COMSAT.  See  "Use  of  Proceeds". This
     refinancing would reduce the  ratios of earnings to  fixed charges for  the
     year  ended December 31, 1994 and for the quarter ended March 31, 1995 on a
     pro forma basis by less than ten percent.

(3)  1990 earnings were  inadequate to cover  fixed charges, as  such terms  are
     defined  in Item  503(d) of Regulation  S-K, with a  coverage deficiency of
     $23,726,000. However,  1990  earnings include  a  $97,576,000  nonrecurring
     charge  related to  the restructuring  of the  video entertainment business
     unit.
</TABLE>

<PAGE>
                                                                   EXHIBIT 23(A)

                         INDEPENDENT AUDITORS' CONSENT

    We  consent to the incorporation by reference in this Registration Statement
of COMSAT  Corporation  on Form  S-3  of our  report  dated February  10,  1995,
appearing  in the Annual Report on Form  10-K of COMSAT Corporation for the year
ended December 31, 1994 and to the references to us under the headings  "Summary
Financial  Information of COMSAT"  and "Experts" in  the Prospectuses, which are
part of this Registration Statement.

Deloitte & Touche LLP

/s/ Deloitte & Touche LLP

Washington, D.C.
June 2, 1995

<PAGE>
                                                                      EXHIBIT 24

                               COMSAT CORPORATION

                               POWERS OF ATTORNEY

    Each  of the  undersigned hereby appoints  Bruce L.  Crockett, President and
Chief Executive Officer,  Allen E.  Flower, Acting Chief  Financial Officer  and
Controller,  Warren Y. Zeger, Vice President, General Counsel and Secretary, and
Robert N. Davis, Jr., Assistant General Counsel, and each of them severally, his
or her true and lawful attorneys to execute (in the name of and on behalf of and
as attorneys for the undersigned) a Registration Statement on Form S-3  relating
to  the offer and sale of up to an aggregate principal amount of $200 million of
non-convertible Monthly  Income  Preferred  Securities  (MIPS),  non-convertible
Quarterly  Income  Preferred Securities  (QUIPS), or  convertible MIPS  or QUIPS
which are convertible into shares of the Corporation's Common Stock, and any and
all amendments to such  Registration Statement, and to  file the same, with  all
exhibits   thereto  and  other  documents  in  connection  therewith,  with  the
Securities and Exchange Commission.

<TABLE>
<S>                                      <C>        <C>
                                            (1)     Principal executive officer

                                                                /s/ BRUCE L. CROCKETT
                                                    ---------------------------------------------
Date: May 19, 1995                                          (Bruce L. Crockett, President
                                                             and Chief Executive Officer)

                                            (2)     Principal financial officer

                                                                 /s/ ALLEN E. FLOWER
                                                    ---------------------------------------------
Date: May 19, 1995                                             (Allen E. Flower, Acting
                                                               Chief Financial Officer)

                                            (3)     Principal accounting officer

                                                                 /s/ ALLEN E. FLOWER
Date: May 19, 1995                                  ---------------------------------------------
                                                            (Allen E. Flower, Controller)

                                            (4)     Board of Directors

                                                                /s/ LUCY WILSON BENSON
Date: May 19, 1995                                  ---------------------------------------------
                                                            (Lucy Wilson Benson, Director)

                                                                 /s/ EDWIN I. COLODNY
Date: May 19, 1995                                  ---------------------------------------------
                                                             (Edwin I. Colodny, Director)

                                                                /s/ BRUCE L. CROCKETT
Date: May 19, 1995                                  ---------------------------------------------
                                                            (Bruce L. Crockett, Director)

                                                             /s/ LAWRENCE S. EAGLEBURGER
Date: May 19, 1995                                  ---------------------------------------------
                                                         (Lawrence S. Eagleburger, Director)

                                                                 /s/ NEAL B. FREEMAN
Date: May 19, 1995                                  ---------------------------------------------
                                                             (Neal B. Freeman, Director)
</TABLE>
<PAGE>
<TABLE>
<S>                                      <C>        <C>
                                                                /s/ BARRY M. GOLDWATER
Date: May 19, 1995                                  ---------------------------------------------
                                                            (Barry M. Goldwater, Director)

                                                                 /s/ ARTHUR HAUSPURG
Date: May 19, 1995                                  ---------------------------------------------
                                                             (Arthur Hauspurg, Director)

                                                                 /s/ PETER S. KNIGHT
Date: May 19, 1995                                  ---------------------------------------------
                                                             (Peter S. Knight, Director)

                                                                 /s/ MELVIN R. LAIRD
                                                    ---------------------------------------------
Date: May 19, 1995                                          (Melvin R. Laird, Chairman of
                                                               the Board and Director)

                                                                 /s/ PETER W. LIKINS
Date: May 19, 1995                                  ---------------------------------------------
                                                             (Peter W. Likins, Director)

                                                    ---------------------------------------------
Date: May 19, 1995                                            (Howard M. Love, Director)

                                                                /s/ CHARLES T. MANATT
Date: May 19, 1995                                  ---------------------------------------------
                                                            (Charles T. Manatt, Director)

                                                                /s/ ROBERT G. SCHWARTZ
Date: May 19, 1995                                  ---------------------------------------------
                                                            (Robert G. Schwartz, Director)

                                                                   /s/ C. J. SILAS
Date: May 19, 1995                                  ---------------------------------------------
                                                               (C. J. Silas, Director)

                                                                /s/ DOLORES D. WHARTON
Date: May 19, 1995                                  ---------------------------------------------
                                                            (Dolores D. Wharton, Director)
</TABLE>

                                       2


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