Exhibit 10.18.3



                                                 March 5, 1998


The News Corporation Limited
New York, New York

Globo Comunicacoes e Participacoes, S.A.
Rio de Janeiro, Brazil

Grupo Televisa, S.A.
Mexico City, Mexico

PanAmSat International Systems, Inc.
Greenwich, Connecticut

Gentlemen:

          Reference is made to that certain letter  agreement dated February 29,
1996,  as amended,  by and among the  entities  recipients  to this letter (also
referred to herein as the "parties") identified above (the "Letter Agreement").

          In that connection, the parties acknowledge and, to the extent that it
may be required, consent to the following:

          (1)  PanAmSat International Systems, Inc., formerly known as PanAmSat
Corporation  ("PanAmSat")  and NetSat Servicos Ltda. (an entity that is owned by
The News Corporation Limited ("News"), Globo Comunicacoes e Participacoes,  S.A.
("Globo"),  and  Tele-Communications  International Inc. ("TINTA")) are about to
enter  into a  "Second  Amended  and  Restated  Transponder  Purchase  and  Sale
Agreement,"  substantially  in the form that has been reviewed by the parties or
their representatives (the "Brazil Agreement");

          (2)  PanAmSat and Sky Multi-Country Partners, previously referenced as
Multi-Country  Partners GP (an entity that is owned by News,  Globo,  TINTA, and
Grupo  Televisa,  S. A.  ("Televisa")),  are about to enter into a  "Transponder
Service  Agreement,"  substantially  in the form that has been  reviewed  by the
parties or their representatives (the "Multi-Country Agreement");

          (3)  The  parties  understand  and agree that the  combination  of the
Brazil  Agreement  and  the   Multi-Country   Agreement   (together  the  "PAS-6
Agreements"),  supersedes  the  Letter  Agreement  as to PAS-3 and PAS-6 and the
rights and obligations of the parties to the Letter Agreement  relative thereto,
but that the  rights and  obligations  of the  parties  to the Letter  Agreement
relative to PAS-5,  except as expressly  set forth  below,  are  unaffected  and
remain binding.


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          (4)  The parties  acknowledge  and agree that [***********************
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     This letter may be executed in several counterparts, each of which shall be
deemed an original,  and all such counterparts together shall constitute but one
and the same instrument.

     Please  indicate  your  agreement  of  the  foregoing  by  signing  in  the
appropriate place indicated below.


Notarized:                          THE NEWS CORPORATION
                                     LIMITED



                                  By:                                         
                                  Its







Notarized:                          GLOBO COMUNICACOES E
                                     PARTICIPACOES, S.A.



                                  By:                                         
                                  Its






[***]     Filed separately with the Commission pursuant to a request for 
          confidential treatment.


<PAGE>


Notarized:                          GRUPO TELEVISA, S.A.



                                  By:                                         
                                  Its


                                             and



                                  By:                                         
                                  Its


                                             and



                                  By:                                         
                                  Its






Notarized:                          PANAMSAT INTERNATIONAL
                                     SYSTEMS, INC.



                                  By:                                         
                                  Its