<PAGE>


                                   AMENDMENT NO. 4

                               CONTRACT NO. 104272-B

                        DIRECT BROADCAST SATELLITE CONTRACT

                                      BETWEEN

                 UNITED STATES SATELLITE BROADCASTING COMPANY, INC.

                                        AND

                            LOCKHEED MARTIN CORPORATION


THIS AMENDMENT is effective December 31, 1997.

WHEREAS, USSB and the Contractor (hereinafter referred to as the "Parties"),
have agreed to an extension in the suspension of all program activities
effective January 1, 1998 through a period not to exceed May 1, 1998 and;

WHEREAS the Parties, recognizing that a specific date ending the extension of
the suspension may occur at any time during such period and;

WHEREAS the Parties, recognizing that changes are required in the Contract, have
created this Amendment No. 4;

NOW THEREFORE, in consideration of the promises and mutual covenants hereinafter
contained, the Parties agree to the following:

I.   Beginning on January 1, 1998, and on the first day of each month thereafter
     until the first day of the subsequent month after Contractor's receipt of
     USSB's written Request for Resumption of Activities, and continuing through
     a period not to exceed May 1, 1998, the Parties agree to amend the Terms
     and Conditions of the subject Contract as follows:

     A.   In Article 3.B, Price, the price of the Spacecraft and the Total
          Contract Price shall be adjusted on a monthly basis as follows:


<TABLE>
<CAPTION>
                                         Total Increase in Price     Total Increase in
Date of Increment    Monthly Increment       of Spacecraft          Total Contract Price
-----------------    -----------------   -----------------------    --------------------
<S>                  <C>                  <C>                        <C>
January 1, 1998
February 1, 1998
March 1, 1998
April 1, 1998

</TABLE>

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     B.   In Article 4.B, Deliverable Items and Delivery Schedule, the
          current delivery schedule for all deliverables will be increased by
          one month for each month this suspension is extended beyond January
          1, 1998.

     C.   In Article 5.A, Progress and Milestone Payments, the Progress
          Payment Plan, beginning with Payment Number 14 and continuing
          through Payment Number 17 will be adjusted to
          each month as follows:


<TABLE>
<CAPTION>
                                         Monthly Total         Cumulative Total
Date of Increment    Payment Number   ($ in U.S. Millions)   ($ in U.S. Millions)
-----------------    ---------------  ---------------------  --------------------
<S>                  <C>               <C>                    <C>
January 1, 1998          14
February 1, 1998         15
March 1, 1998            16
April 1, 1998            17

</TABLE>

     D.   In Article 15A, USSB's Right to Terminate, the Termination Schedule
          shall be changed as follows:



<TABLE>
<CAPTION>
                          Monthly Total         Cumulative Total
Date of Increment      ($ in U.S. Millions)   ($ in U.S. Millions)
-----------------      ---------------------  --------------------
<S>                     <C>                    <C>
January - 1998
   February
    March
    April

</TABLE>


II.  Upon receipt by the Contractor of USSB's written Notice of Resumption of
     Activities, the Parties agree to modify the Articles and Exhibits of this
     Contract.  Such modifications shall, at a minimum, provide the appropriate
     adjustments to the balance of all schedules, amounts, and events described
     and contemplated by this Amendment but not adjusted by this amendment and
     will be predicated on the date of USSB's written Request for Resumption of
     Activities.  In the event that the Parties do not agree to such
     modifications as evidenced by a written amendment to this Contract by May
     1, 1998, this Contract will be considered terminated for the convenience of
     USSB in accordance with the provisions of Article 15.

III. Except as specifically set forth above all other terms and conditions of
     the Contract shall remain in full force and effect in accordance with the
     terms and conditions as originally written and such terms and conditions
     shall not be affected or modified by this Amendment No. 4.

<PAGE>

IN WITNESS THEREOF, the Parties have caused this Amendment No. 4 to be signed by
their duly authorized officer or representative.



United States Satellite Broadcasting     Lockheed Martin Corporation
Company, Inc.


By: /s/ Robert W. Hubbard                By: /s/ Wm. W. Whisenant
   -----------------------------            ------------------------
        Robert W. Hubbard                        Wm. W. Whisenant
        Executive Vice President                 Contract Manager
                                                 Lockheed Martin
                                                 Telecommunications