FORM OF DEPOSIT AGREEMENT

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Exhibit 4.7

FORM OF DEPOSIT AGREEMENT

        This DEPOSIT AGREEMENT is made and entered into as of                        , 200    by and among SI International, Inc., a Delaware corporation (the "Company"),                        , a national banking association, as Depositary, and all holders from time to time of Receipts (as hereinafter defined) issued hereunder.

WITNESSETH:

        WHEREAS, it is desired to provide, as hereinafter set forth in this Deposit Agreement, for the deposit of shares of the Company's Preferred Stock (as hereinafter defined) with the Depositary for the purposes set forth in this Deposit Agreement and for the issuance hereunder of the Receipts evidencing Depositary Shares representing a fractional interest in the Preferred Stock deposited; and

        WHEREAS, the Receipts are to be substantially in the form of Exhibit A annexed to this Deposit Agreement, with appropriate insertions, modifications and omissions, as hereinafter provided in this Deposit Agreement;

        NOW, THEREFORE, in consideration of the premises contained herein, it is agreed by and among the parties hereto as follows:

ARTICLE I

DEFINITIONS

        The following definitions shall apply to the respective terms (in the singular and plural forms of such terms) used in this Deposit Agreement and the Receipts:

        SECTION 1.01. "Certificate of Incorporation" shall mean the Certificate of Incorporation, as amended and supplemented from time to time, of the Company.

        SECTION 1.02. "Certificate of Designation" shall mean the Certificate of Designation Designating            Shares of Preferred Stock as            % Series                         Preferred Stock filed with the Delaware Secretary of State establishing the Preferred Stock as a series of Preferred Stock of the Company.

        SECTION 1.03. "Common Stock" shall mean shares of the Company's common stock, $.01 par value per share.

        SECTION 1.04. "Company" shall mean SI International, Inc., a Delaware corporation, and its successors.

        SECTION 1.05. "Corporate Office" shall mean the corporate office of the Depositary at which at any particular time its business in respect of matters governed by this Deposit Agreement shall be administered, which at the date of this Deposit Agreement is located at

        SECTION 1.06. "Deposit Agreement" shall mean this agreement, as the same may be amended, modified or supplemented from time to time.

        SECTION 1.07. "Depositary" shall mean                        , a company or corporation having its principal office in the United States, and any successor as depositary hereunder.

        SECTION 1.08. "Depositary Share" shall mean a                        fractional interest of a share of Preferred Stock deposited with the Depositary hereunder and the same proportionate interest in any and all other property received by the Depositary in respect of such share of Preferred Stock and held under this Deposit Agreement, all as evidenced by the Receipts issued hereunder. Subject to the terms of this Deposit Agreement, each owner of a Depositary Share is entitled, proportionately, to all the rights, preferences and privileges of the Preferred Stock represented by such Depositary Share,

including the dividend and distribution, voting, redemption, conversion and liquidation rights contained in the Certificate of Designation.

        SECTION 1.09. "Depositary's Agent" shall mean one or more agents appointed by the Depositary as provided, and for the purposes specified, in Section 7.05.

        SECTION 1.10. "Preferred Stock" shall mean shares of the Company's            % Series                        Preferred Stock, $.01 par value per share, heretofore validly issued, fully paid and non-assessable.

        SECTION 1.11. "Receipt" shall mean a Depositary Receipt issued hereunder to evidence one or more Depositary Shares, whether in definitive or temporary form, substantially in the form set forth as Exhibit A hereto.

        SECTION 1.12. "record date" shall mean the date fixed pursuant to Section 4.04.

        SECTION 1.13. "record holder" or "holder" as applied to a Receipt shall mean the person in whose name a Receipt is registered on the books maintained by the Depositary for such purpose.

        SECTION 1.14. "Registrar" shall mean                        , or any bank or trust company appointed to register ownership and transfers of Receipts or the deposited Preferred Stock, as the case may be, as herein provided.

        SECTION 1.15. "Securities Act" shall mean the Securities Act of 1933, as amended.

        SECTION 1.16. "Transfer Agent" shall mean                        , or any bank or trust company appointed to transfer the Receipts or the deposited Preferred Stock, as the case may be, as herein provided.

ARTICLE II

FORM OF RECEIPTS, DEPOSIT OF PREFERRED STOCK, EXECUTION AND DELIVERY, TRANSFER, SURRENDER AND REDEMPTION OF RECEIPTS

        SECTION 2.01.    Form and Transferability of Receipts.    Definitive Receipts shall be engraved or printed or lithographed with steel-engraved borders and underlying tint and shall be substantially in the form set forth in Exhibit A annexed to this Deposit Agreement, with appropriate insertions, modifications and omissions, as hereinafter provided. Pending the preparation of definitive Receipts, the Depositary, upon the written order of the Company, delivered in compliance with Section 2.02, shall execute and deliver temporary Receipts which may be printed, lithographed, typewritten, mimeographed or otherwise substantially of the tenor of the definitive Receipts in lieu of which they are issued and with such appropriate insertions, omissions, substitutions and other variations as the persons executing such Receipts may determine, as evidenced by their execution of such Receipts. If temporary Receipts are issued, the Company and the Depositary will cause definitive Receipts to be prepared without unreasonable delay. After the preparation of definitive Receipts, the temporary Receipts shall be exchangeable for definitive Receipts upon surrender of the temporary Receipts at the Corporate Office or such other offices, if any, as the Depositary may designate, without charge to the holder. Upon surrender for cancellation of any one or more temporary Receipts, the Depositary shall execute and deliver in exchange therefor definitive Receipts representing the same number of Depositary Shares as represented by the surrendered temporary Receipt or Receipts. Such exchange shall be made at the Company's expense and without any charge therefor. Until so exchanged, the temporary Receipts shall in all respects be entitled to the same benefits under this Deposit Agreement, and with respect to the Preferred Stock deposited, as definitive Receipts.

        Receipts shall be executed by the Depositary by the manual or facsimile signature of a duly authorized signatory of the Depositary, provided that if a Registrar (other than the Depositary) shall

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have been appointed then such Receipts shall also be countersigned by manual signature of a duly authorized signatory of the Registrar. No Receipt shall be entitled to any benefits under this Deposit Agreement or be valid or obligatory for any purpose unless it shall have been executed as provided in the preceding sentence. The Depositary shall record on its books each Receipt executed as provided above and delivered as hereinafter provided.

        Except as the Depositary may otherwise determine, Receipts shall be in denominations of any number of whole Depositary Shares. All Receipts shall be dated the date of their issuance.

        Receipts may be endorsed with or have incorporated in the text thereof such legends or recitals or changes not inconsistent with the provisions of this Deposit Agreement as may be required by the Company or required to comply with any applicable law or regulation or with the rules and regulations of any securities exchange or interdealer quotation system upon which the Preferred Stock, the Depositary Shares or the Receipts may be listed or quoted or to conform with any usage with respect thereto, or to indicate any special limitations or restrictions to which any particular Receipts are subject, in each case, as directed by the Company.

        Title to any Receipt (and to the Depositary Shares evidenced by such Receipt) that is properly endorsed or accompanied by a properly executed instrument of transfer or endorsement shall be transferable by delivery with the same effect as in the case of a negotiable instrument; provided, however, that until a Receipt shall be transferred on the books of the Depositary as provided in Section 2.04, the Depositary may, notwithstanding any notice to the contrary, treat the record holder thereof at such time as the absolute owner thereof for the purpose of determining the person entitled to dividends or other distributions, the exercise of any redemption or voting rights or to any notice provided for in this Deposit Agreement and for all other purposes.

        SECTION 2.02.    Deposit of Preferred Stock; Execution and Delivery of Receipts in Respect Thereof.    Concurrently with the execution of this Deposit Agreement, the Company is delivering to the Depositary a certificate or certificates, registered in the name of the Depositary and evidencing            shares of Preferred Stock, properly endorsed or accompanied, if required by the Depositary, by a duly executed instrument of transfer or endorsement, in form satisfactory to the Depositary, together with (i) all such certifications as may be required by the Depositary in accordance with the provisions of this Deposit Agreement and (ii) a written letter of instruction of the Company directing the Depositary to execute and deliver to, or upon the written order of, the person or persons stated in such order a Receipt or Receipts for the Depositary Shares representing such deposited Preferred Stock. The Depositary acknowledges receipt of the deposited Preferred Stock and related documentation and agrees to hold such deposited Preferred Stock in an account to be established by the Depositary at the Corporate Office or at such other office as the Depositary shall determine. The Company hereby appoints the Depositary as the Registrar and Transfer Agent for the Preferred Stock deposited hereunder and the Depositary hereby accepts such appointment and, as such, will reflect changes in the number of shares (including any fractional shares) of deposited Preferred Stock held by it by notation, book-entry or other appropriate method.

        If required by the Depositary, Preferred Stock presented for deposit by the Company at any time, whether or not the register of stockholders of the Company is closed, shall also be accompanied by an agreement or assignment, or other instrument satisfactory to the Depositary, that will provide for the prompt transfer to the Depositary or its nominee of any distribution or right to subscribe for additional Preferred Stock or to receive other property that any person in whose name the Preferred Stock is or has been registered may thereafter receive upon or in respect of such deposited Preferred Stock, or in lieu thereof such agreement of indemnity or other agreement as shall be satisfactory to the Depositary.

        Upon receipt by the Depositary of a certificate or certificates for Preferred Stock deposited hereunder, together with the other documents specified above, and upon registering such Preferred Stock in the name of the Depositary, the Depositary, subject to the terms and conditions of this

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Deposit Agreement, shall execute and deliver to, or upon the order of, the person or persons named in the written order delivered to the Depositary referred to in the first paragraph of this Section 2.02 a Receipt or Receipts for the number of whole Depositary Shares representing the Preferred Stock so deposited and registered in such name or names as may be requested by such person or persons. The Depositary shall execute and deliver such Receipt or Receipts at the Corporate Office, except that, at the request, risk and expense of any person requesting such delivery, such delivery may be made at such other place as may be designated by such person.

        Other than in the case of splits, combinations or other reclassifications affecting the Preferred Stock, or in the case of distributions of Preferred Stock, if any, there shall be deposited hereunder not more than the number of shares constituting the Preferred Stock as set forth in the Certificate of Designation, as such may be amended.

        The Company shall deliver to the Depositary from time to time such quantities of Receipts as the Depositary may request to enable the Depositary to perform its obligations under this Deposit Agreement.

        SECTION 2.03.    Optional Redemption of Preferred Stock for Cash.    Whenever the Company shall elect to redeem shares of deposited Preferred Stock for cash in accordance with the provisions of the Certificate of Designation, it shall (unless otherwise agreed in writing with the Depositary) give the Depositary not less than 30 days' prior written notice of the date of such proposed redemption and of the number of such shares of Preferred Stock held by the Depositary to be redeemed and the applicable redemption price, as set forth in the Certificate of Designation, including the amount, if any, of accrued and unpaid dividends thereon to and including the date fixed for redemption. The Depositary shall mail, first-class postage prepaid, notice of the redemption of Preferred Stock and the proposed simultaneous redemption of the Depositary Shares representing the Preferred Stock to be redeemed, not less than 30 nor more than 60 days prior to the date fixed for redemption of such Preferred Stock and Depositary Shares (the "redemption date"), to the record holders of the Receipts evidencing the Depositary Shares to be so redeemed, at the addresses of such holders as the same appear on the records of the Depositary. No failure to give such notice or any defect thereto or in the mailing thereof shall affect the sufficiency of notice or validity of the proceedings for redemption except as to a holder to whom notice was defective or not given. A redemption notice which has been mailed in the manner provided herein shall be conclusively presumed to have been duly given on the date mailed whether or not the holder received the redemption notice. The Company shall provide the Depositary with such notice, and each such notice shall state: the redemption date; the redemption price and accrued and unpaid dividends payable on the redemption date; the number of shares of deposited Preferred Stock and Depositary Shares to be redeemed; if fewer than all the Depositary Shares held by any holder are to be redeemed, the number of such Depositary Shares held by such holder to be so redeemed; the place or places where Receipts evidencing the Depositary Shares to be redeemed are to be surrendered for payment of the redemption price and accrued and unpaid dividends payable on the redemption date; and that from and after the redemption date dividends in respect of the Preferred Stock represented by the Depositary Shares to be redeemed will cease to accrue. If fewer than all of the outstanding Depositary Shares are to be redeemed, the Depositary Shares to be redeemed shall be redeemed pro rata (as nearly as may be practicable without creating fractional Depositary Shares) or by any other equitable method determined by the Company.

        In the event that notice of redemption has been made as described in the immediately preceding paragraph and the Company shall then have paid or caused to be paid in full to The Depositary the redemption price (determined pursuant to the Certificate of Designation) of the Preferred Stock deposited with The Depositary to be redeemed (including any accrued and unpaid dividends to and including the redemption date), the Depositary shall redeem the number of Depositary Shares representing such Preferred Stock so called for redemption by the Company and from and after the redemption date (unless the Company shall have failed to pay for the shares of Preferred Stock to be

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redeemed by it as set forth in the Company's notice provided for in the preceding paragraph), all dividends in respect of the shares of Preferred Stock called for redemption shall cease to accrue, the Depositary Shares called for redemption shall be deemed no longer to be outstanding and all rights of the holders of Receipts evidencing such Depositary Shares (except the right to receive the redemption price plus all accrued and unpaid dividends to and including the redemption date) shall, to the extent of such Depositary Shares, cease and terminate. Upon surrender in accordance with said notice of the Receipts evidencing such Depositary Shares (properly endorsed or assigned for transfer, if the Depositary or applicable law shall so require), such Depositary Shares shall be redeemed at a redemption price of $            per Depositary Share plus all accrued and unpaid dividends to and including the redemption date. The foregoing shall be further subject to the terms and conditions of the Certificate of Designation. In the event of any conflict between the provisions of this Deposit Agreement and the provisions of the Certificate of Designation, the provisions of the Certificate of Designation will govern and the Company will instruct the Depositary accordingly.

        If fewer than all of the Depositary Shares evidenced by a Receipt are called for redemption, the Depositary will deliver to the holder of such Receipt upon its surrender to the Depositary, together with payment of the redemption price for and all other amounts payable in respect of the Depositary Shares called for redemption, a new Receipt evidencing such holder's Depositary Shares evidenced by such prior Receipt that are not called for redemption.

        The Company acknowledges that the bank accounts maintained by the Depositary in connection with the performance of the services described herein will be in the name of the Depositary and that the Depositary may receive investment earnings in connection with the investment at the Depositary's risk and for its benefit of funds held in those accounts from time to time.

        SECTION 2.04.    Registration of Transfers of Receipts.    The Company hereby appoints the Depositary as the Registrar and Transfer Agent for the Receipts and the Depositary hereby accepts such appointment and, as such, shall register on its books from time to time transfers of Receipts upon any surrender thereof by the holder in person or by a duly authorized attorney, agent or representative, properly endorsed or accompanied by a properly executed instrument of transfer or endorsement and including a guarantee of the signature thereon by a participant in a signature guarantee medallion program approved by the Securities Transfer Association (a "Signature Guarantee"), together with evidence of the payment of any transfer taxes as may be required by applicable law. Upon such surrender, the Depositary shall execute a new Receipt or Receipts and deliver the same to or upon the order of the person entitled thereto evidencing the same aggregate number of Depositary Shares evidenced by the Receipt or Receipts surrendered.

        SECTION 2.05.    Combinations and Split-ups of Receipts.    Upon surrender of a Receipt or Receipts at the Corporate Office or such other office as the Depositary may designate for the purpose of effecting a split-up or combination of Receipts, subject to the terms and conditions of this Deposit Agreement, the Depositary shall execute and deliver a new Receipt or Receipts in the authorized denominations requested evidencing the same aggregate number of Depositary Shares evidenced by the Receipt or Receipts surrendered.

        SECTION 2.06.    Surrender of Receipts and Withdrawal of Preferred Stock.    Any holder of a Receipt or Receipts may withdraw any or all of the deposited Preferred Stock represented by the Depositary Shares evidenced by such Receipt or Receipts and all money and other property, if any, represented by such Depositary Shares by surrendering such Receipt or Receipts at the Corporate Office or at such other office as the Depositary may designate for such withdrawals. After such surrender, without unreasonable delay, the Depositary shall deliver to such holder, or to the person or persons designated by such holder as hereinafter provided, the number of whole or fractional shares of such Preferred Stock and all such money and other property, if any, represented by the Depositary Shares evidenced by the Receipt or Receipts so surrendered for withdrawal, but holders of such whole

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or fractional shares of Preferred Stock will not thereafter be entitled to deposit such Preferred Stock hereunder or to receive Depositary Shares therefor. If the Receipt or Receipts delivered by the holder to the Depositary in connection with such withdrawal shall evidence a number of Depositary Shares in excess of the number of Depositary Shares representing the number of whole or fractional shares of deposited Preferred Stock to be withdrawn, the Depositary shall at the same time, in addition to such number of whole or fractional shares of Preferred Stock and such money and other property, if any, to be withdrawn, deliver to such holder, or (subject to Section 2.04) upon his order, a new Receipt or Receipts evidencing such excess number of Depositary Shares. Delivery of such Preferred Stock and such money and other property being withdrawn may be made by the delivery of such certificates, documents of title and other instruments as the Depositary may deem appropriate, which, if required by the Depositary, shall be properly endorsed or accompanied by a properly executed instrument of transfer or endorsement.

        If the deposited Preferred Stock and the money and other property being withdrawn are to be delivered to a person or persons other than the record holder of the Receipt or Receipts being surrendered for withdrawal of Preferred Stock, such holder shall execute and deliver to the Depositary a written order so directing the Depositary and the Depositary may require that the Receipt or Receipts surrendered by such holder for withdrawal of such shares of Preferred Stock be properly endorsed in blank or accompanied by a properly executed instrument of transfer or endorsement in blank with a Signature Guarantee.

        The Depositary shall deliver the deposited Preferred Stock and the money and other property, if any, represented by the Depositary Shares evidenced by Receipts surrendered for withdrawal at the Corporate Office, except that, at the request, risk and expense of the holder surrendering such Receipt or Receipts and for the account of the holder thereof, such delivery may be made at such other place as may be designated by such holder.

        SECTION 2.07.    Limitations on Execution and Delivery, Transfer, Split-up, Combination.    As a condition precedent to the execution and delivery, transfer, split-up, combination, surrender or exchange of any Receipt, the Depositary, any of the Depositary's Agents or the Company may require any or all of the following: (i) payment to it of a sum sufficient for the payment (or, in the event that the Depositary or the Company shall have made such payment, the reimbursement to it) of any tax or other governmental charge with respect thereto (including any such tax or charge with respect to the Preferred Stock being deposited or withdrawn); (ii) the production of proof satisfactory to it as to the identity and genuineness of any signature (or the authority of any signature), including a Signature Guarantee; and (iii) compliance with such regulations, if any, as the Depositary or the Company may establish consistent with the provisions of this Deposit Agreement as may be required by any securities exchange upon which the deposited Preferred Stock, the Depositary Shares or the Receipts may be included for quotation or listed.

        The deposit of Preferred Stock may be refused, the delivery of Receipts against Preferred Stock may be suspended, the transfer of Receipts may be refused, and the transfer, split-up, combination, surrender, exchange or redemption of outstanding Receipts may be suspended (i) during any period when the register of stockholders of the Company is closed or (ii) if any such action is deemed reasonably necessary or advisable by the Depositary, any of time Depositary's Agents or the Company at any time or from time to time because of any requirement of applicable law or of any government or governmental body or commission, or under any provision of this Deposit Agreement.

        SECTION 2.08.    Lost Receipts, etc.    In case any Receipt shall be mutilated or destroyed or lost or stolen, the Depositary in its discretion may execute and deliver a Receipt of like form and tenor in exchange and substitution for such mutilated Receipt or in lieu of and in substitution for such destroyed, lost or stolen Receipt, provided that the holder thereof provides the Depositary with (i) evidence reasonably satisfactory to the Depositary of such destruction, loss or theft of such Receipt,

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of the authenticity thereof and of his ownership thereof and (ii) reasonable indemnification and the provision of an open penalty surety bond, in each case, satisfactory to the Depositary and the Company and holding the Depositary and the Company harmless.

        SECTION 2.09.    Cancellation and Destruction of Surrendered Receipts.    All Receipts surrendered to the Depositary or any Depositary's Agent shall be cancelled by the Depositary. Except as prohibited by applicable law or regulation, the Depositary is authorized to destroy such Receipts so cancelled.

ARTICLE III

CERTAIN OBLIGATIONS OF hOLDERS OF RECEIPTS AND THE COMPANY

        SECTION 3.01.    Filing Proofs, Certificates and Other Information.    Any person presenting Preferred Stock for deposit or any holder of a Receipt may be required from time to time to file such proof of residence or other information and to execute such certificates as the Depositary or the Company may reasonably deem necessary or proper. The Depositary or the Company may withhold or delay the delivery of any Receipt, the transfer, redemption or exchange of any Receipt, the withdrawal of the deposited Preferred Stock represented by the Depositary Shares evidenced by any Receipt, the distribution of any distribution or the sale of any rights or of the proceeds thereof, until such proof or other information is filed or such certificates are executed.

        SECTION 3.02.    Payment of Fees and Expenses.    Holders of Receipts shall be obligated to make payments to the Depositary of certain fees and expenses, as provided in Section 5.09, or provide evidence reasonably satisfactory to the Depositary that such fees and expenses have been paid. Until such payment is made, transfer of any Receipt or any withdrawal of the Preferred Stock or money or other property, if any, represented by the Depositary Shares evidenced by such Receip