EXHIBIT 4.3


                 [Letterhead of Hughes Electronics Corporation]

July 22, 1998

PanAmSat Corporation
One Pickwick Plaza
Greenwich, Connecticut 06880
Attn:    Michael Inglese
         Vice President, Finance

Dear Mr. Inglese:

     Reference is hereby made to that certain  Loan  Agreement,  dated as of May
15,  1997  between  PanAmSat  Corporation  ("PanAmSat")  and Hughes  Electronics
Corporation  ("Hughes")  (as  from  time  to  time  amended,  the  "Hughes  Loan
Agreement")  pursuant  to which  Hughes has  extended a credit  facility  in the
amount of $1,725,000,000 to PanAmSat  evidenced by the promissory note dated May
15, 1997 (as from time to time amended, the "Hughes Note").

     Reference  is also  made to  that  certain  Credit  Agreement  dated  as of
February 20, 1998, with certain financial institutions (collectively,  including
without  limitation,  any entity  acquiring  the rights of a "Lender"  under the
Credit  Agreement,  the "Lenders"),  each of the  Co-Documentation  Agents party
thereto, and the Administrative Agent (as from time to time amended, the "Senior
Credit  Agreement"),  providing among other things for the making of advances by
the Lenders to PanAmSat (the "Advances") in an aggregate principal amount at any
one time outstanding up to $500,000,000.

     Reference  is  also  made  to  that  certain  Subordination  and  Amendment
Agreement  dated  as of  February  20,  1998  among  PanAmSat,  Hughes  and  the
Administrative  Agent for the Lenders,  providing  that Hughes  subordinate  its
rights under the Hughes Note to the rights of the Lenders in connection with the
Advances.

     You have  advised  us that you  intend to issue a maximum  of  $500,000,000
maximum principal amount short-term  unsecured notes (the "Notes",  collectively
the  "Commercial  Paper  Program"),  to rank pari passu with the Company's other
unsecured  and  unsubordinated  indebtedness.  You have also advised us that the
Notes are exempt from registration under the Securities Act of 1933, as amended,
pursuant to Section 4(2) thereof.  The Notes will carry  maturity  dates of less
than 270 days from the date of issuance.

     You have  requested  that Hughes (1)  consent to the  issuance of the Notes
under the Hughes Loan  Agreement,  and (2) agree to subordinate its rights under
the Hughes  Note to the Notes in a manner that is  substantially  similar to the
subordination granted in favor of the Advances.

     In  consideration  of the  foregoing,  and  for  other  good  and  valuable
consideration, the receipt and sufficiency of which are hereby acknowledged, the
parties hereto hereby agree as follows:

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     1.  Hughes  hereby  consents  to the  issuance  of the Notes by PanAmSat on
substantially  the  terms and  conditions  set  forth in the  Private  Placement
Memorandum attached hereto.

     2. Hughes hereby agrees to subordinate  its rights under the Hughes Note to
the Notes on substantially the same terms as its agreement to subordinate to the
Advances as set forth in the Subordination Agreement, including, but not limited
to, Sections 3, 4, 5 and 7 of thereof.

     3. PanAmSat agrees that so long as the Hughes Note remains  outstanding (a)
it shall obtain Hughes' prior written consent to any material  modifications  or
amendments to the Commercial Paper Program;  (b) the aggregate  principal amount
outstanding  under  the  Notes  combined  with the  aggregate  principal  amount
outstanding  under the Advances shall not exceed  $500,000,000;  and (c) none of
the Notes shall have a maturity date beyond the last maturity date of any of the
Advances.

     4. So  long  as  Notes  are  outstanding  and  Moody's  Investors  Services
("Moody's) is rating the Notes,  Hughes  agrees to notify  Moody's in writing at
least 30 days prior to any amendment, modification or termination of this letter
agreement.

     5. This letter  agreement  shall be deemed an amendment or  modification to
the Loan  Agreement,  and shall be  subject  to all of the terms and  conditions
contained therein.

     The Loan Agreement shall remain unchanged in all other respects.

     If you are in agreement with the foregoing,  kindly sign this letter on the
line provided below and return a copy to our attention.


                                            HUGHES ELECTRONICS CORPORATION

                                            By:   Edward B. Clarkson
                                               --------------------------
                                            Name:  Edward B. Clarkson
                                            Title:  Assistant Treasurer


Agreed and acknowledged as of July 22, 1998

PANAMSAT CORPORATION

By:    Michael J. Inglese
   --------------------------
Name:  Michael J. Inglese
Title:  Vice President, Finance