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                                                                     Exhibit 5.1

                         [Latham & Watkins Letterhead]

                                March 31, 2000


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

          Re:      Registration Statement on Form S-3, File No. 333-31758;
                   2,875,000 Shares of Common Stock, par value $.0001 per share

Ladies and Gentlemen:

          In connection with the registration by ViaSat, Inc., a
Delaware corporation (the "Company"), of 2,875,000 shares of common stock of the
Company, par value $.0001 per share (the "Shares"), under the Securities Act of
1933, as amended (the "Act"), on a Registration Statement on Form S-3 filed with
the Securities and Exchange Commission (the "Commission") on March 6, 2000 (File
No. 333-31758), as amended by Amendment No. 1 thereto filed with the Commission
on March 31, 2000 (collectively, the "Registration Statement"), you have
requested our opinion with respect to the matters set forth below.

          In our capacity as your 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.

          In our examination, we have assumed the genuineness of all signatures,
the authenticity of all documents submitted to us as originals, and the
conformity to authentic original documents of all documents submitted to us as
copies.

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

          Subject to the foregoing, it is our opinion that the Shares have been
duly authorized, and, upon issuance, delivery and payment therefor in the manner
contemplated by the Registration Statement, will be validly issued, fully paid
and nonassessable.

          We consent to your filing this opinion as an exhibit to the
Registration Statement and to the reference to our firm contained under the
heading "Legal Matters."

                                        Very truly yours,

                                        /S/ LATHAM & WATKINS