<PAGE>
                                                                    EXHIBIT 10.3

            *** CERTAIN CONFIDENTIAL INFORMATION HAS BEEN OMITTED AND
           FILED WITH THE SECURITIES AND EXCHANGE COMMISSION PURSUANT
                    TO A REQUEST FOR CONFIDENTIAL TREATMENT


                               AMENDMENT NO. 3 TO
                  AMENDED AND RESTATED REVOLVING LOAN AGREEMENT

               THIS AMENDMENT NO. 3 TO AMENDED AND RESTATED REVOLVING LOAN
AGREEMENT (this "Amendment"), dated as of August 12, 2003, is entered into by
and among the financial institutions listed on the signature pages hereof
(individually, a "Lender" and collectively, the "Lenders"), Union Bank of
California, N.A., as Administrative Agent (in such capacity, the "Administrative
Agent"), Comerica Bank (formerly Comerica Bank-California), as Collateral Agent,
and ViaSat, Inc., a Delaware corporation (the "Borrower"), with reference to the
following facts:

                                    RECITALS

The Borrower, the Lenders, the Administrative Agent and the Collateral Agent are
parties to the Amended and Restated Revolving Loan Agreement, dated as of
December 31, 2002, as amended (the "Loan Agreement"), pursuant to which the
Lenders have provided the Borrower with a Revolving Loan facility and a
subfacility for Letters of Credit.

The parties wish to amend the Loan Agreement as set forth below.

                                    AGREEMENT

            NOW, THEREFORE, the parties hereby agree as follows:

        1. Defined Terms. Any and all initially capitalized terms used in this
Amendment (including, without limitation, in the recitals hereto) without
definition shall have the respective meanings specified in the Loan Agreement.

        2. New Grid Pricing Definitions. Section 1.1 of the Loan Agreement is
hereby amended and supplemented by adding the following new definitions in
appropriate alphabetical order:

                "'Applicable Base Rate Margin' means, for each Pricing Period,
                the interest rate margin set forth below (expressed in basis
                points per annum) opposite the Applicable Pricing Level for that
                Pricing Period:


                                      -1-
<PAGE>

<TABLE>
<CAPTION>
                         Applicable Margin
                           Pricing Level
                           -------------
<S>                                               <C>
                                I                  ***

                                II                 ***

                                III                ***
</TABLE>


        'Applicable Commitment Fee Rate' means, for each Pricing Period, the
        rate set forth below (expressed in basis points per annum) opposite the
        Applicable Pricing Level for that Pricing Period:

<TABLE>
<CAPTION>

                            Applicable         Commitment
                           Pricing Level          Fee
                           -------------       ----------
<S>                                               <C>
                                 I                 ***

                                II                 ***

                                III                ***
</TABLE>


        'Applicable Eurodollar Rate Margin' means, for each Pricing Period, the
        interest rate margin set forth below (expressed in basis points per
        annum) opposite the Applicable Pricing Level for that Pricing Period:


<TABLE>
<CAPTION>
                            Applicable
                           Pricing Level         Margin
                           -------------         ------
<S>                                              <C>
                                I                  ***

                                II                 ***

                                III                ***
</TABLE>


        'Applicable Pricing Level' means, for each Pricing Period, the pricing
        level set forth below opposite the Leverage Ratio as of the last day of
        the Fiscal Quarter most recently ended prior to the commencement of that
        Pricing Period:

<TABLE>
<CAPTION>
                   Pricing Level                     Leverage Ratio
                   -------------                     --------------
<S>                                      <C>
                         I               Less than 1.00 to 1.00
</TABLE>


                                      -2-
<PAGE>

<TABLE>
<S>                                       <C>
                         II               Greater than or equal to 1.00 to
                                          1.00, but less than 1.50 to 1.00

                         III              Greater than or equal to 1.50 to 1.00
</TABLE>


               provided that (i) in the event that Borrower does not deliver a
               Pricing Certificate to the Administrative Agent with respect to
               any Pricing Period prior to the commencement of such Pricing
               Period, then until such Pricing Certificate is delivered to the
               Administrative Agent, the Applicable Pricing Level for that
               Pricing Period shall be Pricing Level III, but once Borrower has
               delivered a Pricing Certificate with respect to such Pricing
               Period, then any resulting change in the Applicable Pricing Level
               shall be made retroactively to the beginning of such Pricing
               Period, and (ii) if any Pricing Certificate is subsequently
               determined to be in error, then any resulting change in the
               Applicable Pricing Level shall be made retroactively to the
               beginning of the relevant Pricing Period.

               'Pricing Certificate' means a certificate in the form of Exhibit
               K, properly completed and signed by a Senior Officer or his or
               her designated representative of Borrower.

               'Pricing Period' means (a) the period commencing on August 16,
               2003 and ending on November 17, 2003, (b) the period commencing
               on November 18, 2003 and ending on February 16, 2003, and (c)
               thereafter the period commencing on each May 19, August 18,
               November 17 and February 16 and ending on the next following
               August 17, November 16, February 15, or May 18, respectively. "

        3. Amendment to Commitment: Section 1.1 of the Loan Agreement is hereby
amended such that the definition of "Commitment" set forth therein is amended to
read in full as follows:

               "`Commitment' means, subject to Section 2.5, $30,000,000. The
               respective Pro Rata Shares of the Lenders with respect to the
               Commitment are set forth in Schedule 1.1."

        4. Amendment to Commitment: Section 1.1 of the Loan Agreement is hereby
amended such that the definition of "EBITDA" set forth therein is amended to
read in full as follows:

               "'EBITDA' means, with respect to any fiscal period and with
respect to Borrower and its Subsidiaries on a consolidated basis, the sum of (a)
income from operations as set forth on the Borrower's GAAP statement of
operation, plus (b) depreciation, plus (c) amortization (without duplication)."


                                      -3-
<PAGE>

        5. Amendment to Revolving Loan Maturity Date: Section 1.1 of the Loan
Agreement is hereby amended such that the definition of "Revolving Loan Maturity
Date" set forth therein is amended to read in full as follows:

               "'Revolving Loan Maturity Date' means September 30, 2004."

        6. Amendment to Letters of Credit. Section 2.4(a) of the Loan Agreement
is hereby amended to read in full as follows:

               "(a) The Existing Letters of Credit described in Schedule 2.4
               shall be Letters of Credit for all purposes under this Agreement.

                  (1) Subject to the terms and conditions hereof, at any time
                      and from time to time from the Closing Date through the
                      Revolving Loan Maturity Date, the Issuing Lender shall
                      issue such Letters of Credit under the Commitment as
                      Borrower may request by a Request for Letter of Credit;
                      provided that:

                      (i)  giving effect to all such Letters of Credit, the sum
                           of:

                           (A) the aggregate principal amount outstanding under
                               the Revolving Notes; plus

                           (B) the Aggregate Effective Amount of all outstanding
                               Letters of Credit, does not exceed the then
                               applicable Commitment; and

                      (ii) the Aggregate Effective Amount under all outstanding
                           Letters of Credit does not exceed $10,000,000.

                  (2) Each Letter of Credit shall be in a form reasonably
                      acceptable to the Issuing Lender.

                  (3) Unless all the Lenders otherwise consent in a writing
                      delivered to the Administrative Agent, the term of any
                      Letter of Credit (other than any Existing Letters of
                      Credit) shall not exceed one (1) year.

                  (4) The term of any Letter of Credit (other than any Existing
                      Letters of Credit) shall not extend one hundred eighty
                      (180) days beyond the Revolving Loan Maturity Date unless:

                      i)   all the Lenders otherwise consent in a writing
                           delivered to the Administrative Agent;

                      ii)  the Borrower provides the Issuing Lender with cash
                           collateral in the amount equal to 100% of the face
                           amount of the Requested Letter of Credit (or such
                           lesser amount as shall then


                                      -4-
<PAGE>

                           be available for drawing under the Requested Letter
                           of Credit); or

                      iii) the Borrower provides the Issuing Lender with a
                           "back-up" standby letter of credit in the full face
                           amount of the Requested Letter of Credit (or such
                           lesser amount as shall then be available under the
                           Requested Letter of Credit) issued by a bank
                           acceptable to the Issuing Bank in its reasonable
                           discretion.

        7. Amendment to Base Rate Interest Rate Provision. Section 3.1(b) is
hereby amended to read in full as follows:

               "(b) Interest accrued on each Base Rate Loan shall be due and
               payable on each Monthly Payment Date. Except as otherwise
               provided in Sections 3.1(d) and 3.8, the unpaid principal amount
               of any Base Rate Loan shall bear interest at a fluctuating rate
               per annum equal to the Base Rate plus the Applicable Base Rate
               Margin. Each change in the interest rate under this Section
               3.1(b) due to a change in the Base Rate shall take effect
               simultaneously with the corresponding change in the Base Rate."

        8. Amendment to Eurodollar Rate Interest Rate Provision. Section 3.1(c)
is hereby amended to read in full as follows:

               "(c) Interest accrued on each Eurodollar Rate Loan shall be due
               and payable on the last day of the related Eurodollar Period.
               Except as otherwise provided in Sections 3.1(d) and 3.8, the
               unpaid principal amount of any Eurodollar Rate Loan shall bear
               interest at a rate per annum equal to the Eurodollar Rate for
               that Eurodollar Rate Loan plus the Applicable Eurodollar Rate
               Margin."

        9. Amendment to Commitment Fee. Section 3.3 is hereby amended to read in
full as follows:

               " 3.3 Commitment Fee. From the Closing Date through the Revolving
               Loan Maturity Date, Borrower shall pay to the Administrative
               Agent, for the ratable accounts of the Lenders pro rata according
               to their Pro Rata Share of the Revolving Commitment, a commitment
               fee equal to the Applicable Commitment Fee Rate per annum times
               the average daily amount by which the Commitment exceeds the (i)
               aggregate daily principal Indebtedness evidenced by the Revolving
               Notes plus (ii) the Aggregate Effective Amount of all Letters of
               Credit then outstanding. The commitment fee shall be payable
               quarterly in arrears as of each Quarterly Payment Date within ten
               (10) days after receipt by Borrower of an invoice therefor from
               the Administrative Agent."

        10. Amendment to Letter of Credit Fee. Section 3.4(a) is hereby amended
to read in full as follows:


                                      -5-
<PAGE>

               "(a) concurrently with the issuance of each Standby Letter of
               Credit, to the Administrative Agent a standby letter of credit
               fee in an amount equal to the Applicable Eurodollar Margin per
               annum times the face amount of such Standby Letter of Credit
               through the termination or expiration of such Standby Letter of
               Credit, the first 10% of which fee the Administrative Agent shall
               promptly pay to UBOC and the remainder of which fee the
               Administrative Agent shall promptly pay to the Lenders ratably,
               in accordance with their respective Pro Rata Shares of the
               Commitment;"

        11. Amendment to Eurodollar Prepayment Fee. Section 3.6(e)(2) is hereby
amended to read in full as follows:

               "(e)(2) the amount, if any, by which (i) the additional interest
               would have accrued on the amount prepaid or not borrowed at the
               Eurodollar Rate plus the Applicable Eurodollar Rate Margin if
               that amount had remained or been outstanding through the last day
               of the applicable Eurodollar Period exceeds (ii) the interest
               that the Lender could recover by placing such amount on deposit
               in the Designated Eurodollar Market for a period beginning on the
               date of the prepayment or failure to borrow and ending on the
               last day of the applicable Eurodollar Period (or, if no deposit
               rate quotation is available for such period, for the most
               comparable period for which a deposit rate quotation may be
               obtained); plus"

        12. Amendment to Minimum EBITDA Covenant. Section 6.13 of the Loan
Agreement is hereby amended to read in full as follows:

               "6.13 EBITDA. Permit EBITDA for any Fiscal Quarter of Borrower
               to be less than $***."

        13. Delivery of Pricing Certificate. Section 7.1(b) of the Loan
Agreement is hereby amended to read in full as follows:

               "(b) As soon as practicable, and in any event within 45 days
               after the end of each Fiscal Quarter, a Pricing Certificate
               setting forth a calculation of the Leverage Ratio as of the last
               day of such Fiscal Quarter, and providing reasonable detail as to
               the calculation thereof, which calculations in the case of the
               fourth Fiscal Quarter in any Fiscal Year shall be based on the
               preliminary unaudited financial statements of Borrower and its
               Subsidiaries for such Fiscal Quarter, and as soon as practicable
               thereafter, in the event of any material variance in the actual
               calculation of the Leverage Ratio from such preliminary
               calculation, a revised Pricing Certificate setting forth the
               actual calculation thereof;"

        14. Amendment to Schedule of Commitments. Schedule 1.1 to the Loan
Agreement is hereby amended and replaced by Schedule 1.1 to this Amendment.


                                      -6-
<PAGE>

        15. New Pricing Certificate. The Loan Agreement is hereby further
amended and supplemented by adding a new Exhibit K thereto in the form of
Exhibit K to this Amendment. Borrower represents and warrants that Borrower will
deliver a completed Pricing Certificate no later than August 15, 2003 with
regard to the pricing period ended June 30, 2003.

        16. Amendment Fee. In consideration of the Lenders' agreement to enter
into this Amendment and provide the Borrower with the accommodations described
herein, on the effective date of this Amendment, the Borrower shall pay to the
Administrative Agent, for the ratable benefit of the Lenders, a one-time fee of
$*** (the "Amendment Fee"). The Borrower acknowledges and agrees that, at the
Administrative Agent's option, the Administrative Agent may effect payment of
the Amendment Fee by charging the full amount of such fee, when due, to the
Borrower's Revolving Loan account or to the Borrower's checking account at Union
Bank of California, N.A.

        17. Condition Precedent. The effectiveness of this Amendment shall be
subject to the prior satisfaction of each of the following conditions:

            (b)  This Amendment. The Agent shall have received an original of
                 this Amendment, duly executed by the Borrower and each of the
                 Lenders;

            (c)  Certificate. The Assistant Secretary of Borrower shall have
                 executed the Certificate of Resolution attached to this
                 Amendment;

            (d)  Revolving Note to Union Bank. Borrower shall have executed a
                 Revolving Note, in the original principal amount of $15,00,000,
                 to the order of Union Bank of California, N.A;

            (e)  Revolving Note to Comerica Bank. Borrower shall have executed a
                 Revolving Note, in the original principal amount of $15,00,000,
                 to the order of Comerica Bank - California;

            (f)  Other Documents. The Borrower shall have executed and delivered
                 to the Agent such other documents and instruments as the Agent
                 may reasonably require.

        18. Miscellaneous.

            (a)  Survival of Representations and Warranties. All representations
                 and warranties made in the Loan Agreement or in any other
                 document or documents relating thereto, including, without
                 limitation, any Loan Document furnished in connection with this
                 Amendment, shall survive the execution and delivery of this
                 Amendment and the other Loan Documents, and no investigation by
                 the Administrative Agent or the Lenders or any closing shall
                 affect the representations and warranties or the right of the
                 Administrative Agent or any Lender to rely thereon.


                                      -7-
<PAGE>

            (b)  No Events of Default. The Borrower is not aware of any events
                 which now constitute, or with the passage of time or the giving
                 of notice, or both, would constitute, an Event of Default under
                 the Loan Agreement.

            (c)  Reference to Loan Agreement. The Loan Agreement, each of the
                 other Loan Documents, and any and all other agreements,
                 documents or instruments now or hereafter executed and
                 delivered pursuant to the terms hereof, or pursuant to the
                 terms of the Loan Agreement as amended hereby, are hereby
                 amended so that any reference therein to the Loan Agreement
                 shall mean a reference to the Loan Agreement as amended hereby.

            (d)  Loan Agreement Remains in Effect. The Loan Agreement and the
                 other Loan Documents remain in full force and effect and the
                 Borrower ratifies and confirms its agreements and covenants
                 contained therein. The Borrower hereby confirms that, after
                 giving effect to this Amendment, no Event of Default or Default
                 exists as of such date.

            (e)  Severability. Any provision of this Amendment held by a court
                 of competent jurisdiction to be invalid or unenforceable shall
                 not impair or invalidate the remainder of this Amendment and
                 the effect thereof shall be confined to the provision so held
                 to be invalid or unenforceable.

            (f)  APPLICABLE LAW. THIS AMENDMENT AND ALL OTHER LOAN DOCUMENTS
                 EXECUTED PURSUANT HERETO SHALL BE DEEMED TO HAVE BEEN MADE AND
                 TO BE PERFORMABLE IN THE STATE OF CALIFORNIA AND SHALL BE
                 GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE
                 STATE OF CALIFORNIA.

            (g)  Successors and Assigns. This Amendment is binding upon and
                 shall inure to the benefit of the Lenders and the Borrower and
                 their respective successors and assigns; provided, however,
                 that the Borrower may not assign or transfer any of its rights
                 or obligations hereunder without the prior written consent of
                 the Lenders.

            (h)  Counterparts. This Amendment may be executed in one or more
                 counterparts, each of which when so executed shall be deemed to
                 be an original, but all of which when taken together shall
                 constitute one and the same instrument.


                                      -8-
<PAGE>

            (i)  Headings. The headings, captions and arrangements used in this
                 Amendment are for convenience only and shall not affect the
                 interpretation of this Amendment.

            (j)  NO ORAL AGREEMENTS. THIS AMENDMENT, TOGETHER WITH THE OTHER
                 LOAN DOCUMENTS AS WRITTEN, REPRESENTS THE FINAL AGREEMENT
                 BETWEEN THE LENDERS AND THE BORROWER AND MAY NOT BE
                 CONTRADICTED BY EVIDENCE OF PRIOR, CONTEMPORANEOUS OR
                 SUBSEQUENT ORAL AGREEMENTS OF THE PARTIES. THERE ARE NO
                 UNWRITTEN ORAL AGREEMENTS BETWEEN THE LENDERS AND THE BORROWER.

                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]


                                      -9-
<PAGE>

               IN WITNESS WHEREOF, the parties have entered into this Amendment
by their respective duly authorized officers as of the date first above written.

                                 VIASAT, INC.

                                 By:____________________________
                                        Ronald G. Wangerin
                                        Vice President and Chief
                                 Financial Officer

                                 UNION BANK OF CALIFORNIA, N.A., as
                                 the Administrative Agent

                                 By:
                                    --------------------------------------
                                        Douglas S. Lambell
                                        Vice President

                                 COMERICA BANK-CALIFORNIA,
                                 as the Collateral Agent

                                 By:
                                    --------------------------------------
                                        Stephen M. Cusato
                                        Senior Vice President

                                 UNION BANK OF CALIFORNIA, N.A., as
                                 a Lender


                                 By:
                                    --------------------------------------
                                        Douglas S. Lambell
                                        Vice President

                                 COMERICA BANK - CALIFORNIA,
                                 as a Lender

                                 By:
                                    --------------------------------------
                                        Stephen M. Cusato
                                        Senior Vice President


                                      -10-
<PAGE>

                                  SCHEDULE 1.1

                               LENDER COMMITMENTS

<TABLE>
<CAPTION>
                                           Revolving Commitment Amount             Pro Rata Share
                                           ---------------------------             --------------
<S>                                                 <C>                                 <C>
UNION BANK OF CALIFORNIA, N.A.                      $15,000,000                         50%
COMERICA BANK                                       $15,000,000                         50%
                                                    ===========                         ===
Total:                                              $30,000,000                        100%
</TABLE>




                                      -11-