EXHIBIT 4.3.4

                   [Hughes Electronics Corporation Letterhead]


October 22, 1998

PanAmSat Corporation
One Pickwick Plaza
Greenwich, Connecticut 06880
Attn:  Kenneth N. Heintz
       Executive Vice President and
       Chief Financial Officer

Dear Mr. Heintz:

         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,   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 in an  aggregate
principal amount at any one time outstanding up to $500,000,000.

         On January 16, 1998, PanAmSat completed a private placement pursuant to
Rule 144A of the Securities Act of 1933, as amended,  for $750 million aggregate
principal  amount of new debt  securities  (the  "Notes").  The  purpose of this
letter is to formalize  Hughes'  agreement to  subordinate  its rights under the
Hughes  Note  to  the  rights  of  the  holders  of  the  Notes  (including  any
replacements or exchanges thereof).

         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:

         Hughes hereby confirms and agrees that the  obligations  represented by
the Hughes Note are and shall be subordinated and subject in right of payment to
the prior payment in full of the Notes.

         Notwithstanding  the foregoing,  PanAmSat may make regularly  scheduled
payments  of  interest  on the Hughes  Note and  PanAmSat  may make  payments of
principal on the Hughes Note on or after January 1, 2001, in an aggregate amount
not  exceeding  in any fiscal year of PanAmSat an amount  equal to 50% of Excess
Cash Flow (as defined in the Senior Credit  Agreement) for the preceding  fiscal
year of PanAmSat,  as set forth in the annual financial  statements of PanAmSat.
In addition,  so long as no Event of Default  under the  indenture has occurred,
PanAmSat  may at any time make  payments of principal of the Hughes Note (a) out
of the proceeds of any issuance by PanAmSat of shares of capital stock,  (b) out
of the  proceeds  of any  issuance  by  PanAmSat  of  subordinated  debt that is
subordinated on terms substantially the same as the Hughes Note, (c) in exchange
for equity of PanAmSat,  or (d) in connection with any refinancing of the Hughes
Note.  Hughes agrees that if there shall occur an Event of Default (as such term
is defined in the  indenture  for the Notes),  no payment shall be made on or in
respect of the Hughes Note until such time as the trustee for the holders of the
Notes  notifies  PanAmSat  that such Event of Default has been  remedied,  after
which PanAmSat may resume making required payments under the Hughes Note.

         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 January 16, 1998:

PANAMSAT CORPORATION

By:  Kenneth N. Heintz
Name:  Kenneth N. Heintz
Title:  Executive Vice President and Chief Financial Officer