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                                                                     EXHIBIT 5.1


                           OPINION OF LATHAM & WATKINS

                                 August 7, 2001


ViaSat, Inc.
6155 El Camino Real
Carlsbad, California 92009

      Re: Form S-8 Registration Statement;
          3,600,000 Shares of Common Stock

Ladies and Gentlemen:

      In connection with the registration by ViaSat, Inc., a Delaware
corporation (the "Company"), of 3,600,000 shares of common stock, par value
$.0001 per share (the "Shares"), of the Company to be issued pursuant to The
1996 Equity Participation Plan of ViaSat, Inc., as amended (the "1996 Plan"),
under the Securities Act of 1933, as amended, on a Registration Statement on
Form S-8 filed with the Securities and Exchange Commission on August 7, 2001 (as
amended from time to time, the "Registration Statement"), you have requested our
opinion with respect to the matters set forth below.

      In our capacity as the Company's counsel in connection with such
registration, we are familiar with the proceedings taken and proposed to be
taken by the Company in connection with the authorization, issuance and sale of
the Shares, and for the purposes of this opinion, have assumed such proceedings
will be timely completed in the manner presently proposed. In addition, we have
made such legal and factual examinations and inquiries, including an examination
of originals or copies certified or otherwise identified to our satisfaction of
such documents, corporate records and instruments, as we have deemed necessary
or appropriate for purposes of this opinion.

      We are opining herein as to the effect on the subject transaction only of
the General Corporation Law of the State of Delaware, and we express no opinion
with respect to the applicability thereto, or the effect thereon, of the laws of
any other jurisdiction or any other laws, or as to any matters of municipal law
or the laws of any other local agencies within the state.

      Subject to the foregoing, it is our opinion that as of the date hereof the
Shares have been duly authorized, and, upon the issuance of and payment for the
Shares in accordance with the terms set forth in the 1996 Plan, the Shares will
be validly issued, fully paid and nonassessable.

      We consent to your filing this opinion as an exhibit to the Registration
Statement.


                                        Very truly yours,

                                        /s/ LATHAM & WATKINS