Document:

<PAGE>

                                                                     Exhibit 4.2

                     BUSINESS LOAN AND SECURITY AGREEMENT

                          dated as of December 17, 2001

                                  by and among

                        MANTECH INTERNATIONAL CORPORATION
                         AND CERTAIN OF ITS SUBSIDIARIES
                              as Borrower Parties,

                         CITIZENS BANK OF PENNSYLVANIA,

                         PNC BANK, NATIONAL ASSOCIATION,

                  BRANCH BANKING AND TRUST COMPANY OF VIRGINIA

                                       and

                            CHEVY CHASE BANK, F.S.B.,
                               as Lender Parties,

                         CITIZENS BANK OF PENNSYLVANIA,
                             as Administrative Agent

                                       and

                         PNC BANK, NATIONAL ASSOCIATION,
                             as Documentation Agent

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                                TABLE OF CONTENTS
<TABLE>
<S>                                                                                     <C>
CERTAIN DEFINITIONS..................................................................   6
ARTICLE 1 COMMITMENT.................................................................   18
   1.1.     Maximum Loan Amount......................................................   18
   1.2.     Use of Proceeds..........................................................   19
   1.3.     Borrowing Base and Maximum Advances......................................   19
   1.4.     Advances.................................................................   21
   1.5.     Additional Mandatory Payments; Reduction of Commitment...................   21
   1.6.     Field Audits.............................................................   22
   1.7.     Certain Fees.............................................................   23
   1.8.     Intentionally Omitted....................................................   23
   1.9.     Appointment of the Parent Company........................................   24
   1.10.    Joinder of New Subsidiaries and Affiliates...............................   24
ARTICLE 2 LETTERS OF CREDIT..........................................................   24
   2.1.     Issuance.................................................................   24
   2.2.     Amounts Advanced Pursuant to Letters of Credit...........................   25
   2.3.     Letter of Credit Fees....................................................   25
ARTICLE 3 SECURITY...................................................................   26
   3.1.     Security Generally.......................................................   26
   3.2.     No Preference or Priority................................................   27
ARTICLE 4 CONDITIONS TO THE LENDERS' OBLIGATIONS.....................................   27
   4.1.     Compliance with Law and Agreements; Third Party Consents.................   27
   4.2.     Financial Condition......................................................   28
   4.3.     Opinion of Counsel.......................................................   28
   4.4.     No Default...............................................................   28
   4.5.     Documentation............................................................   28
   4.6.     Closing Costs and Expenses...............................................   28
ARTICLE 5 REPRESENTATIONS AND WARRANTIES.............................................   28
   5.1.     Corporate Existence and Qualification....................................   28
   5.2.     Corporate Authority; Noncontravention....................................   29
   5.3.     Financial Position.......................................................   29
   5.4.     Payment of Taxes.........................................................   29
   5.5.     Accuracy of Submitted Information; Omissions.............................   29
   5.6.     Government Contracts.....................................................   30
   5.7.     No Defaults or Liabilities...............................................   30
   5.8.     No Violations of Law.....................................................   30
   5.9.     Litigation and Proceedings...............................................   30
   5.10.    Security Interest in the Collateral......................................   30
   5.11.    Principal Place of Business; Location of Books and Records...............   30
   5.12.    Fiscal Year..............................................................   31
   5.13.    Pension Plans............................................................   31
   5.14.    O.S.H.A. and Environmental Compliance....................................   31
   5.15.    Intellectual Property....................................................   32
   5.16.    Existing or Pending Defaults; Material Contracts.........................   32
   5.17.    Leases and Real Property.................................................   33
   5.18.    Labor Relations..........................................................   33
   5.19.    Assignment of Government Contracts.......................................   33
   5.20.    Contribution Agreement...................................................   33
</TABLE>

<PAGE>

<TABLE>
<S>                                                                                         <C>
   5.21.    Intentionally Deleted........................................................   33
   5.22.    Ownership of the Borrowers...................................................   33
   5.23.    Solvency.....................................................................   34
   5.24.    Survival of Representations and Warranties...................................   34
ARTICLE 6 AFFIRMATIVE COVENANTS OF THE BORROWERS.........................................   34
   6.1.     Payment of Loan Obligations..................................................   34
   6.2.     Payment of Taxes.............................................................   34
   6.3.     Delivery of Financial and Other Statements...................................   34
   6.4.     Maintenance of Records; Review by the Lenders................................   35
   6.5.     Maintenance of Insurance Coverage............................................   35
   6.6.     Maintenance of Property/Collateral; Performance of Contracts.................   36
   6.7.     Maintenance of Corporate Existence...........................................   36
   6.8.     Maintenance of Certain Accounts with the Administrative Agent................   36
   6.9.     Maintenance of Management....................................................   36
   6.10.    Disclosure of Defaults, Etc..................................................   36
   6.11.    Security Perfection; Assignment of Claims Act; Payment of Costs..............   37
   6.12.    Defense of Title to Collateral...............................................   38
   6.13.    Compliance with Law..........................................................   38
   6.14.    Other Collateral Covenants...................................................   38
   6.15.    Financial Covenants of the Borrowers.........................................   40
   6.16.    Intentionally Omitted........................................................   41
   6.17.    Landlord Waivers; Subordination..............................................   41
   6.18.    Substitute Notes.............................................................   41
   6.19.    Interest Rate Contracts......................................................   41
ARTICLE 7 NEGATIVE COVENANTS OF THE BORROWERS............................................   42
   7.1.     Change of Control; Disposition of Assets; Merger.............................   42
   7.2.     Margin Stocks................................................................   43
   7.3.     Change of Operations.........................................................   43
   7.4.     Judgments; Attachments.......................................................   43
   7.5.     Further Assignments; Performance and Modification of Contracts; etc..........   44
   7.6.     Affect Rights of the Administrative Agent or Lenders.........................   44
   7.7.     Indebtedness; Granting of Security Interests.................................   44
   7.8.     Dividends; Loans; Advances; Investments and Similar Events...................   46
   7.9.     Lease Obligations............................................................   48
   7.10.    Duty Deferment Bond..........................................................   48
   7.11.    Lockbox Deposits.............................................................   48
ARTICLE 8 COLLATERAL ACCOUNT.............................................................   48
ARTICLE 9 DEFAULT AND REMEDIES...........................................................   49
   9.1.     Events of Default............................................................   49
   9.2.     Remedies.....................................................................   50
ARTICLE 10 THE AGENTS; AGENCY............................................................   52
   10.1.    Appointment..................................................................   52
   10.2.    General Nature of Agents' Duties.............................................   53
   10.3.    Exercise of Powers...........................................................   53
   10.4.    General Exculpatory Provisions...............................................   54
   10.5.    Administration by the Agent..................................................   55
   10.6.    Lenders Not Relying on Agent or Other Lenders................................   56
   10.7.    Indemnification..............................................................   56
   10.8.    Agent in its Individual Capacity; Agents' Commitment.........................   57
</TABLE>

                                       ii

<PAGE>

<TABLE>
<S>                                                                                       <C>
   10.9.    Holders of Notes...........................................................   57
   10.10.   Successor Agent............................................................   57
   10.11.   Additional Agents..........................................................   58
   10.12.   Calculations...............................................................   58
   10.13.   Funding by the Administrative Agent........................................   59
   10.14.   Benefit of Article.........................................................   60
ARTICLE 11 CERTAIN ADDITIONAL RIGHTS AND  OBLIGATIONS REGARDING THE COLLATERAL.........   61
   11.1.    Power of Attorney..........................................................   61
   11.2.    Lockbox....................................................................   62
   11.3.    Other Agreements...........................................................   62
ARTICLE 12 MISCELLANEOUS...............................................................   62
   12.1.    Remedies Cumulative........................................................   62
   12.2.    Waiver.....................................................................   63
   12.3.    Notices....................................................................   63
   12.4.    Entire Agreement...........................................................   64
   12.5.    Relationship of the Parties................................................   64
   12.6.    Waiver of Jury Trial.......................................................   65
   12.7.    Submission to Jurisdiction; Service of Process; Venue......................   65
   12.8.    Changes in Capital Requirements............................................   66
   12.9.    Captions...................................................................   66
   12.10.   Modification and Waiver....................................................   66
   12.11.   Transferability............................................................   66
   12.12.   Governing Law; Binding Effect..............................................   67
   12.13.   Gender; Number.............................................................   67
   12.14.   Joint and Several Liability................................................   67
   12.15.   Materiality................................................................   67
   12.16.   Reliance on the Administrative Agent.......................................   67
   12.17.   Counterparts...............................................................   67
</TABLE>

EXHIBITS
--------

Exhibit 1      Request for Advance and Certification
Exhibit 1(a)   Request for Swing Line Loan Advance
Exhibit 2      LIBOR Election Form and Certification
Exhibit 3      LIBOR Interest Election Procedure and Requirements
Exhibit 4      Borrowing Base/Non-Default Certificate
Exhibit 5      Quarterly Covenant Compliance/Non-Default Certificate
Exhibit 6      Form of Joinder Agreement
Exhibit 7      Financial Statements
Exhibit 8      Escrow Agreement
Exhibit 9      Pricing Grid
Exhibit 10     Form of Assignment and Acceptance Agreement
Exhibit 11     First Source Debt Letter Agreement

SCHEDULES
---------

Schedule 1       Lender Commitments/Percentages
Schedule 2       Principal Business Location(s)

                                      iii

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Schedule 4.3         Borrowers Excluded from Opinion(s)
Schedule 5.6         Government Contracts (to be assigned)
Schedule 5.9         Litigation and Proceedings
Schedule 5.11        Borrower's Business Locations
Schedule 5.15 (a)    Intellectual Property
Schedule 5.15(b)     Intellectual Property Royalty Payments
Schedule 5.16(a)     Material Contracts
Schedule 5.18        Labor Agreements
Schedule 5.22(a)     Borrower Ownership
Schedule 5.22(b)     Minority Shareholders
Schedule 5.23        Insolvent Entities
Schedule 7.7(a)      Existing Indebtedness
Schedule 7.7(c)      Liens Securing Existing Indebtedness
Schedule 7.8(c)      Existing Loans, Advances and/or Investments (to
                     non-Borrowers)
Schedule 9.1         Entities to be Liquidated or Dissolved

                                       iv

<PAGE>

                      BUSINESS LOAN AND SECURITY AGREEMENT
                      ------------------------------------

         THIS BUSINESS LOAN AND SECURITY AGREEMENT is executed as of the 17/th/
day of December, 2001 and is by and among (i) CITIZENS BANK OF PENNSYLVANIA, a
Pennsylvania state chartered bank ("Citizens Bank"), acting in the capacity of
Lender, Swing Line Lender and as the Administrative Agent for the Lenders,
having offices at 8521 Leesburg Pike, Suite 405, Vienna, Virginia 22182; (ii)
PNC BANK, NATIONAL ASSOCIATION, a national banking association ("PNC"), acting
in the capacity of Lender and as the Documentation Agent for the Lenders, having
offices at One PNC Plaza, 6/th/ Floor, 249 Fifth Avenue, Pittsburgh,
Pennsylvania 15222; (iii) BRANCH BANKING AND TRUST COMPANY OF VIRGINIA, a
Virginia banking corporation ("BB&T"), having offices at 8200 Greensboro Drive,
Suite 250, McLean, Virginia 22102, CHEVY CHASE BANK, F.S.B., a federal savings
bank ("Chevy Chase"), having offices at 7501 Wisconsin Avenue, 12/th/ Floor,
Bethesda, MD 20814, and other "Lender" parties to this Business Loan and
Security Agreement from time to time; (iv) MANTECH INTERNATIONAL CORPORATION, a
New Jersey corporation; MANTECH INTERNATIONAL CORPORATION, a Delaware
corporation; MANTECH ADVANCED SYSTEMS INTERNATIONAL, INC., a Virginia
corporation; MANTECH SYSTEMS ENGINEERING CORPORATION, a Virginia corporation;
NSI TECHNOLOGY SERVICES CORPORATION, a California corporation; MANTECH SYSTEMS
CORPORATION, a New Jersey corporation; MANTECH SOLUTIONS CORPORATION, a Virginia
corporation; MANTECH ENVIRONMENTAL TECHNOLOGY, INC., a Virginia corporation;
MANTECH SUPPORT TECHNOLOGY, INC., a Virginia corporation; MANTECH AUSTRALIA
INTERNATIONAL, INC., a Virginia corporation formerly known as ManTech Computer
Company, Inc.; FIELD SUPPORT SERVICES Muhendislik lIMITED SIRKETI, a corporation
organized and existing under the laws of Turkey; MASI U.K. LIMITED, a
corporation organized and existing under the laws of the United Kingdom; MANTECH
TELECOMMUNICATIONS AND INFORMATION SYSTEMS CORPORATION, a Delaware corporation
formerly known as ManTech Strategic Associates, Ltd.; TECHNOLOGY MANAGEMENT
CORPORATION, a Virginia corporation; SCIENCE ENGINEERING & ANALYSIS,
INCORPORATED, a Virginia corporation; MANTECH ENVIRONMENTAL RESEARCH SERVICES
CORP., a Virginia corporation; NSI ENVIRONMENTAL SOLUTIONS, INC., a Virginia
corporation; MANTECH ENVIRONMENTAL CORPORATION, a Virginia corporation; MANTECH
SYSTEMS SOLUTIONS CORPORATION, a Virginia corporation formerly known as
Tidewater Consultants, Inc.; MANTECH SOLUTIONS & TECHNOLOGIES CORPORATION, a
Virginia corporation formerly known as ManTech Systems Integration Corporation;
MANTECH TEST SYSTEMS, INC., a Virginia corporation; MANTECH U.K. SYSTEMS
CORPORATION, a Virginia corporation; REDESMUNDIAL, S.A., a corporation organized
and existing under the laws of the Republic of Panama formerly known as ManTech
International Panama, Inc.; MANTECH GERMANY SYSTEMS CORPORATION, a Virginia
corporation; MANTECH CHINA SYSTEMS CORPORATION, a Virginia corporation; MANTECH
ADVANCED DEVELOPMENT GROUP, INC., a California corporation; MANTECH ENTERPRISE
SOLUTIONS, INC., a Virginia corporation; MANTECH ADVANCED RECOGNITION LIMITED, a
private company registered in England under the number 885326 formerly known as
Advanced Recognition Limited; VOBIX CORPORATION, a Virginia corporation; MANTECH
DATABASE SERVICES EUROPE LIMITED, a corporation organized and

<PAGE>

existing under the laws of the United Kingdom; MANTECH SECURITY TECHNOLOGIES
CORPORATION, a Virginia corporation, with all such corporations having principal
offices located at the location(s)s listed on Schedule 2 hereto; and (v) each
                                              ----------
other person or entity hereafter becoming a "Borrower" party to this Business
Loan and Security Agreement by executing a "Joinder Agreement" pursuant to this
Business Loan and Security Agreement.

                          W I T N E S S E T H  T H A T:
                          - - - - - - - - - -  - - - -

         In consideration of the mutual covenants and agreements herein
contained, Ten Dollars ($10.00) and other good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged, the parties hereto
agree, represent and warrant as follows:

                               CERTAIN DEFINITIONS
                               -------------------

         For the purposes of this Business Loan and Security Agreement, the
terms set forth below shall have the following definitions:

         "Account Debtor" shall mean any person or entity who is indebted to one
(1) or more of the Borrowers for the payment of any Receivable; it being
understood and agreed that when computations are being made with respect to
amounts due and owing from an Account Debtor (a) such computations shall be made
on a contract by contract basis (as opposed to on an Account Debtor basis), with
respect to amounts owing in connection with Government Contracts, and (b) such
computations shall be made on the basis of all amounts due from the Account
Debtor and any other person or entity related to or affiliated with the
particular Account Debtor, with respect to amounts owing in connection with
contracts which are not Government Contracts.

         "Accounts" shall mean all the funds and accounts now or hereafter owned
or held by a Borrower and all monies, Receivables, Investment Property, Security
Entitlements and other property on deposit therein or credited thereto,
including without limitation, all "Accounts," as such term is now or hereafter
defined in the UCC, whether now owned or hereafter acquired, including (a) all
accounts receivable, other receivables, book debts and other forms of
obligations (other than forms of obligations evidenced by Chattel Paper, or
Instruments), (including any such obligations that may be characterized as an
account or contract right under the UCC), (b) all rights in, to and under all
purchase orders or receipts for goods or services, (c) all rights to any goods
represented by any of the foregoing (including unpaid sellers' rights of
rescission, replevin, reclamation and stoppage in transit and rights to
returned, reclaimed or repossessed goods), (d) all rights to payment due for
property sold, leased, licensed, assigned or otherwise disposed of, for a policy
of insurance issued or to be issued, for a secondary obligation incurred or to
be incurred, for energy provided or to be provided, for the use or hire of a
vessel under a charter or other contract, arising out of the use of a credit
card or charge card, or for services rendered or to be rendered in connection
with any other transaction (whether or not yet earned by performance), (e) all
"health care insurance receivables", as defined in the UCC and (f) all
collateral security of any kind, given by any person or entity with respect to
any of the foregoing.

                                        2

<PAGE>

         "Additional Equity Stock" shall mean the shares of either treasury
stock or newly issued preferred stock, common stock or other equity interests
(including options, warrants or rights to purchase) of any Borrower issued to
any person or entity from and after the date hereof.

         "Administration Fee" shall have the meaning assigned to such term in
Section 1.7(a) of this Agreement.

         "Administrative Agent" shall mean Citizens Bank, acting in its capacity
as administrative agent for the Lenders, or any successor Administrative Agent
appointed pursuant to Section 10.10 of this Agreement.

         "Administrative Agent's Fee" shall have the meaning assigned to such
term in Section 1.7 of this Agreement.

         "Agent" or Agents" shall mean the Administrative Agent and the
Documentation Agent, individually or collectively, as the context may require.

         "Agent's Spot Rate of Exchange" shall mean the spot rate of exchange as
determined by the Administrative Agent, based on the Reuters FX Page, for the
purchase of the relevant currency in the London foreign exchange market with
U.S. Dollars at or about 9:00 a.m. on any date of determination.

         "Agreement" or "Loan Agreement" shall mean this Business Loan and
Security Agreement, together with the schedules and exhibits attached hereto and
any and all amendments or modifications of this Business Loan and Security
Agreement.

         "Annual Excess Cash Limitation" shall mean the Dollar Equivalent Amount
of Five Hundred Thousand and No/100 Dollars ($500,000.00).

         "Applicable Interest Rate" shall mean either the (i) LIBOR Lending Rate
or (ii) Base Rate, as set forth in the Notes.

         "Applicable Laws" shall mean any federal, state or local law,
ordinance, rule or regulation to which any Borrower or the property of any
Borrower is subject, whether domestic or international.

         "Approved ESOP" shall have the meaning assigned to such term in Section
7.1(b) of this Agreement.

         "Approved ESPP" shall have the meaning assigned to such term in Section
7.1(b) of this Agreement.

         "ARL" shall mean ManTech Advanced Recognition Limited, a private
company registered in England under the number 885326 formerly known as Advanced
Recognition Limited.

         "Base Rate" shall mean the higher of the (i) Federal Funds Rate plus
one-half of one percent (.50%) or (ii) Prime Rate.

                                        3

<PAGE>

         "Borrower" and "Borrowers" shall mean, respectively, each and all of
the following entities, as the context may require: MANTECH INTERNATIONAL
CORPORATION, a New Jersey corporation; MANTECH INTERNATIONAL CORPORATION, a
Delaware corporation; MANTECH ADVANCED SYSTEMS INTERNATIONAL, INC., a Virginia
corporation; MANTECH SYSTEMS ENGINEERING CORPORATION, a Virginia corporation;
NSI TECHNOLOGY SERVICES CORPORATION, a California corporation; MANTECH SYSTEMS
CORPORATION, a New Jersey corporation; MANTECH SOLUTIONS CORPORATION, a Virginia
corporation; MANTECH ENVIRONMENTAL TECHNOLOGY, INC., a Virginia corporation;
MANTECH SUPPORT TECHNOLOGY, INC., a Virginia corporation; MANTECH AUSTRALIA
INTERNATIONAL, INC., a Virginia corporation formerly known as ManTech Computer
Company, Inc.; FIELD SUPPORT SERVICES Muhendislik Limited sirketi, a corporation
organized and existing under the laws of Turkey; MASI U.K. LIMITED, a
corporation organized and existing under the laws of the united kingdom; MANTECH
TELECOMMUNICATIONS AND INFORMATION SYSTEMS CORPORATION, a Delaware corporation
formerly known as ManTech strategic associates, ltd.; TECHNOLOGY MANAGEMENT
CORPORATION, a Virginia corporation; SCIENCE ENGINEERING & ANALYSIS,
INCORPORATED, a Virginia corporation; MANTECH ENVIRONMENTAL RESEARCH SERVICES
CORP., a Virginia corporation; NSI ENVIRONMENTAL SOLUTIONS, INC., a Virginia
corporation; MANTECH ENVIRONMENTAL CORPORATION, a Virginia corporation; MANTECH
SYSTEMS SOLUTIONS CORPORATION, a Virginia corporation formerly known as
Tidewater Consultants, Inc.; MANTECH TEST SYSTEMS, INC., a Virginia corporation;
MANTECH SOLUTIONS & TECHNOLOGIES CORPORATION, a Virginia corporation formerly
known as ManTech Systems Integration Corporation; MANTECH U.K. SYSTEMS
CORPORATION, a Virginia corporation; REDESMUNDIAL, S.A., a corporation organized
and existing under the laws of the Republic of Panama formerly known as ManTech
International Panama, Inc.; MANTECH CHINA SYSTEMS CORPORATION, a Virginia
corporation; MANTECH GERMANY SYSTEMS CORPORATION, a Virginia corporation;
MANTECH ADVANCED DEVELOPMENT GROUP, INC., a California corporation; MANTECH
ENTERPRISE SOLUTIONS, INC., a Virginia corporation; MANTECH ADVANCED RECOGNITION
LIMITED, a private company registered in England under the number 885326
formerly known as Advanced Recognition Limited; VOBIX CORPORATION, a Virginia
corporation; MANTECH DATABASE SERVICES EUROPE LIMITED, a corporation organized
and existing under the laws of the United Kingdom; MANTECH SECURITY TECHNOLOGIES
CORPORATION, a Virginia corporation; and each other person or entity hereafter
executing a Joinder Agreement pursuant to Section 1.10 of this Agreement.

         "Borrowing Base/Non-Default Certificate" shall mean a certificate in
the form of Exhibit 4 hereto.
            ---------

         "Borrowing Base Deficiency" shall have the meaning assigned to such
term in Section 1.3 of this Agreement.

         "Business Day" shall mean (a) any day which is neither a Saturday or
Sunday nor a legal holiday on which commercial banks are authorized or required
to be closed in the Commonwealth of Virginia; (b) when such term is used to
describe a day on which a borrowing, payment, prepaying, or repaying is to be
made in respect of any LIBOR Rate Loan, any day

                                        4

<PAGE>

which is: (i) neither a Saturday or Sunday nor a legal holiday on which
commercial banks are authorized or required to be closed in New York City; and
(ii) a London Banking Day; and (c) when such term is used to describe a day on
which an interest rate determination is to be made in respect of any LIBOR Rate
Loan, any day which is a London Banking Day.

         "CERCLA" shall mean the Comprehensive Environmental Response,
Compensation and Liability Act of 1980, as amended (42 U.S.C. Sections 9601 et
                                                                            --
seq.).
---

         "Chattel Paper" shall have the meaning assigned to that term under the
UCC, and shall include "electronic chattel paper" and "tangible chattel paper",
as such terms are defined in the UCC, whether now owned or hereafter acquired by
a Borrower.

         "Citizens Bank" shall mean Citizens Bank of Pennsylvania, a
Pennsylvania state chartered bank, acting individually, together with its
successors and assigns.

         "Closing" shall mean the settlement of the transactions contemplated by
this Agreement.

         "Closing Date" shall mean the date of this Agreement.

         "Collateral" shall have the meaning assigned to such term in Article 3
of this Agreement.

         "Collateral Account" shall have the meaning assigned to such term in
Article 8 of this Agreement.

         "Commercial Contract" shall mean any written contract to which a
Borrower is a party (other than a Government Contract or a contract with the
District of Columbia or any department, instrumentality or agency thereof) which
gives rise or may give rise to Receivables.

         "Commercial Tort Claims" shall have the meaning assigned that term
under the UCC, and shall include any and all claims now existing or hereafter
arising in tort with respect to which (a) the claimant is an organization, or
(b) the claimant is an individual and the claim (i) arose in the course of the
claimant's business or profession, and (ii) does not include damages arising out
of personal injury to or death of any individual.

         "Commitment Amount" shall mean Seventy-one Million Four Hundred
Thousand and No/100 Dollars ($71,400,000.00), or if the maximum aggregate
commitment of the Lenders hereunder is reduced pursuant to the terms of this
Agreement, such lesser amount.

         "Commitment Fee" shall have the meaning assigned to such term in
Section 1.7 of this Agreement.

         "Commitment Letter" shall mean that certain letter dated November 13,
2001, from the Administrative Agent to the Parent Company relating to the Loan,
including the Term Sheet and schedules annexed thereto.

         "Contribution Agreement" shall mean the Contribution Agreement of even
date herewith, by and among the Borrowers, and delivered by the Borrowers prior
to or simultaneously with their execution and delivery of this Agreement or a
Joinder Agreement, as

                                        5

<PAGE>

applicable, together with all Administrative Agent-approved amendments and
modifications thereof hereafter executed and delivered by the Borrowers.

         "Deposit Accounts" shall have the meaning assigned to that term under
the UCC, and shall include any demand, time, savings, passbook or similar
account from time to time established and maintained with a bank.

         "Documents" shall have the meaning assigned to that term under the UCC,
and shall include any and all Documents whether now owned or hereafter created
or acquired.

         "Documentation Agent" shall mean PNC Bank, National Association, acting
in its capacity as the documentation agent for the Lenders, or any successor
Documentation Agent appointed pursuant to Section 10.10 of this Agreement.

         "Dollar Equivalent Amount" shall mean, as of any applicable date of
determination, (i) with respect to amounts denominated in U.S. Dollars, the
amount of U.S. Dollars, and (ii) with respect to amounts denominated in a
Foreign Currency, the amount of U.S. Dollars into which such sums could be
converted as determined initially by the Borrowers by reference to the Agent's
Spot Rate of Exchange as of the applicable date of determination (or such other
reasonable method as the Administrative Agent may approve in writing), and
subject to verification and revision by the Administrative Agent.

         "Duty Deferment Bond" shall mean that certain Duty Deferment Bond
issued by First Union National Bank, London Branch for the benefit of H.M.
Customs and Excise on behalf of ARL in the original principal amount of Forty
Thousand British Pounds Sterling (40,000(pound)), as modified, amended,
increased or decreased pursuant to the terms of this Agreement.

         "EBITDA" shall mean, as of the date of any determination, the
Borrowers' net earnings (or loss) after taxes, plus interest expense, plus all
charges against income for foreign, federal, state and local income taxes, plus
depreciation expense, plus amortization expense, and with respect to
determinations for the four (4) quarters ending September 30, 2001, December 31,
2001, March 31, 2002 and June 30, 2002, plus Twelve Million Five Hundred Two
Thousand and No/100 Dollars ($12,502,000.00) for discontinued operations, all as
determined on a consolidated basis in accordance with GAAP.

         "Eligible ARL Accounts Receivable" shall mean all Receivables which (a)
represent amounts due and owing for products actually delivered or services
actually performed or rendered by or on behalf of ARL to or for the benefit of
an Account Debtor; (b) have been properly billed by ARL; (c) arise in the
ordinary course of ARL's business; (d) are due, owing and not subject to any
defense, set-off or counterclaim; (e) are not final invoices; (f) do not
represent Deferred Revenue (as defined according to GAAP); and (g) are not
otherwise Ineligible Receivables.

         "Eligible Assignee" shall mean any Lender, an affiliate of any Lender,
a Federal Reserve Bank or any other "Qualified Institutional Buyer", as such
term is defined under Rule 144(A), promulgated under the Securities Act of 1933,
as amended.

                                        6

<PAGE>

         "Eligible Billed Government Accounts Receivable" shall mean all
Receivables arising from Government Contracts which (a) represent amounts due
and owing for products actually delivered or services actually performed or
rendered by or on behalf of a Borrower pursuant to a Government Contract; (b)
have been properly billed; (c) arise in the ordinary course of the Borrower's
business; (d) are due, owing and not subject to any defense, set-off or
counterclaim; (e) are not final invoices; and (f) are not otherwise Ineligible
Receivables.

         "Eligible Billed Commercial Accounts Receivable" shall mean all
Receivables which (a) represent amounts due and owing for products actually
delivered or services actually performed or rendered by or on behalf of a
Borrower to or for the benefit of an Account Debtor (other than the Government);
(b) have been properly billed; (c) arise in the ordinary course of the
Borrower's business; (d) are due, owing and not subject to any defense, set-off
or counterclaim; (e) are not final invoices; and (f) are not otherwise
Ineligible Receivables.

         "Eligible Unbilled Government Accounts Receivable" shall mean all
Receivables arising from work actually performed by a Borrower pursuant to a
Government Contract which (a) are eligible to be billed to the Government in
accordance with the applicable Government Contract within thirty (30) days of
the "as of" date of the applicable Borrowing Base/Non-Default Certificate (with
no additional performance required by any person, and no condition to payment by
the Government, other than receipt of an appropriate invoice); (b) have not been
billed to the Government solely as a result of timing differences between the
date the revenue is recognized on the Borrower's books and the date the invoice
is actually rendered; (c) represent revenue recognized on the books of the
Borrower not more than ninety (90) days prior to the "as of" date of the
applicable Borrowing Base/Non-Default Certificate as it relates to "milestones"
(with no additional performance required by any person, and no condition to
payment by the Government; i.e., all necessary Government written consents and
approvals have been obtained, whether in connection with a required contract
modification or otherwise); (d) may, in accordance with GAAP, be included as
current assets of the Borrower, even though such amounts have not been billed to
the Government; and (e) are not Ineligible Receivables.

         "Enterprise Resource Planning Operating Lease" shall mean Schedule 1 of
that certain Lease Agreement No. LA-5015 dated December 29, 2000, between the
Parent Company and CG Commercial Funding providing for the ERP/People Soft Human
Resources and Financial Management System.

         "Equipment" shall have the meaning assigned to that term under the UCC,
and shall include any and all of the following, whether now owned or hereafter
acquired and wherever located: machinery and equipment, including processing
equipment, conveyors, machine tools, data processing and computer equipment,
including embedded software and peripheral equipment and all engineering,
processing and manufacturing equipment, office machinery, furniture, materials
handling equipment, tools, attachments, accessories, automotive equipment,
trailers, trucks, forklifts, molds, dies, stamps, motor vehicles, rolling stock
and other equipment of every kind and nature, trade fixtures and fixtures not
forming a part of real property, together with all additions and accessions
thereto, replacements therefor, all parts therefor, all substitutes for any of
the foregoing, fuel therefor, and all manuals, drawings, instructions,
warranties and rights with respect thereto, and all products and proceeds
thereof and condemnation awards and insurance proceeds with respect thereto.

                                        7

<PAGE>

         "ERISA" shall have the meaning assigned to such term in Section 5.13(a)
of this Agreement.

         "Euro" shall mean the single currency to which the Participating Member
States of the European Union are or have converted.

         "Event of Default" shall have the meaning assigned to such term in
Section 9.1 of this Agreement.

         "Excess Cash Event" shall mean (i) any sale or disposition of any of
the assets of any Borrower which is (a) not in the ordinary course of business;
or (b) prohibited by the terms of this Agreement; (ii) the issuance by any
Borrower after the date of this Agreement of debt securities or other debt
obligations (other than in connection with debt expressly permitted pursuant to
Section 7.7 of this Agreement); (iii) the receipt by or on behalf of any
Borrower of insurance proceeds (other than recoveries due to damage to property,
which recoveries are promptly applied toward repair or replacement of the
damaged property, or recoveries for business interruption loss or workers
compensation insurance proceeds); (iv) the reversion of any pension plan assets;
and/or (v) any other extraordinary cash event resulting in excess cash to a
Borrower, including, without limitation, cash proceeds resulting from the
issuance of additional equity interests or capital stock by a Borrower (other
than the issuance of additional equity interests or capital stock by a Borrower
pursuant to an Approved ESOP or an Approved ESPP).

         "Facility" or "Facilities" shall mean Facility A, Facility B and/or the
Swing Line Facility, individually or collectively, as the context may require.

         "Facility A" shall mean the revolving credit facility being extended
pursuant to this Agreement on the basis of Eligible Billed Government Accounts
Receivable, Eligible Billed Commercial Accounts Receivable, Eligible Unbilled
Government Accounts Receivable and Eligible ARL Accounts Receivable, in the
maximum principal amount of Sixty-five Million and No/100 Dollars
($65,000,000.00), with a sub-limit of Ten Million and No/100 Dollars
($10,000,000.00) for Letters of Credit.

         "Facility A Commitment Amount" shall mean Sixty-five Million and No/100
Dollars ($65,000,000.00), or if such amount shall be reduced pursuant to this
Agreement, such lesser amount.

         "Facility A Commitment Fee" shall have the meaning assigned to such
term in Section 1.7(b) of this Agreement.

         "Facility B" shall mean the term loan being extended pursuant to this
Agreement, in the original principal amount of Six Million Four Hundred Thousand
and No/100 Dollars ($6,400,000.00).

         "Facility B Commitment Amount" shall mean Six Million Four Hundred
Thousand and No/100 Dollars ($6,400,000.00).

         "Federal Funds Rate" for any day shall mean the rate per annum (rounded
upward to the nearest 1/8 of 1%) determined by the Administrative Agent to be
the rate per annum announced by the Federal Reserve Bank of New York (or any
successor) on such day as being

                                        8

<PAGE>

the weighted average of the rates on overnight Federal Funds transactions
arranged by Federal Funds brokers on the previous trading day, as computed and
announced by such Federal Reserve Bank (or any successor) in substantially the
same manner as such Federal Reserve Bank computes and announces the weighted
average it refers to as the "Federal Funds Effective Rate" as of the date of
this Agreement; provided that if such Federal Reserve Bank (or its successor)
                --------
does not announce such rate on any day, the "Federal Funds Effective Rate" for
such day shall be the Federal Funds Rate for the last day on which such rate was
announced.

         "First Source Debt" shall have the meaning assigned to that term in
Section 7.7(a) of this Agreement.

         "First Source Debt Credit Agreement" shall mean that certain
Subordinated Credit Agreement dated as of January 9, 1998 by and among the
Parent Company and the other Borrower parties thereto, First Source Financial
LLP, as Agent, and the Financial Institutions named therein.

         "Fixed Charge Coverage Ratio" shall have the meaning assigned to such
term in Section 6.15(b) of this Agreement.

         "Foreign Currency" and "Foreign Currencies" shall mean British Pounds
Sterling issued by the Bank of England and Euros under the European Monetary
Union, individually or collectively as the context may require.

         "GAAP" shall mean generally accepted accounting principles.

         "General Intangibles" shall have the meaning assigned to that term
under the UCC, and shall include any and all of the following, whether now owned
or hereafter created or acquired: all right, title and interest in or under any
contract, all "payment intangibles", as defined in the UCC, customer lists,
licenses, copyrights, trademarks, patents, and all applications therefor and
reissues, extensions or renewals thereof, rights in intellectual property,
interests in partnerships, joint ventures and other business associations,
licenses, permits, copyrights, trade secrets, proprietary or confidential
information, inventions (whether or not patented or patentable), technical
information, procedures, designs, knowledge, know how, software, data bases,
data, skill, expertise, experience, processes, models, drawings, materials and
records, goodwill (including the goodwill associated with any trademark or
trademark license), all rights and claims in or under insurance policies
(including insurance for fire, damage, loss and casualty, whether covering
personal property, real property, tangible rights or intangible rights, all
liability, life, key man and business interruption insurance, and all unearned
premiums), uncertificated securities, choses in action, deposit, checking and
other bank accounts, rights to receive tax refunds and other payments, rights to
receive dividends, distributions, cash, Instruments and other property in
respect of or in exchange for pledged stock and investment property, rights of
indemnification, all books and records, correspondence, credit files, invoices
and other papers, including without limitation all tapes, cards, computer runs
and other papers and documents.

         "Goods" shall have the meaning assigned to that term under the UCC, and
shall include any and all of the following, whether now owned or hereafter
acquired and wherever located: embedded software to the extent included in
"goods" as defined in the UCC,

                                        9

<PAGE>

manufactured homes, standing timber that is cut and removed for sale,
"as-extracted collateral" as defined in the UCC, and unborn young of animals.

         "Government" shall mean the United States government or any department,
instrumentality or agency thereof, and any state government or any department,
instrumentality or agency thereof; it being expressly understood and agreed that
the District of Columbia is not included within this definition of Government.

         "Government Contract Assignments" shall have the meaning assigned to
such term in Section 6.11 of this Agreement.

         "Government Contracts" shall mean (i) written contracts between any
Borrower and the Government; and (ii) written subcontracts between any Borrower
and a prime contractor who is providing goods or services to the Government
pursuant to a written contract with the Government (the "Prime Contract"),
provided that the subcontract relates only to goods or services being provided
to the Government pursuant to the Prime Contract.

         "GSE" shall mean GSE Systems, Inc., a Delaware corporation.

         "Hazardous Substance" shall mean, without limitation, any flammable
explosives, radon, radioactive materials, asbestos, urea formaldehyde foam
insulation, polychlorinated biphenyls, petroleum and petroleum products,
methane, hazardous materials, hazardous wastes, hazardous or toxic substances,
pollutants or contaminants as defined in CERCLA, HMTA, RCRA or any other
applicable environmental law, rule, order or regulation.

         "Hazardous Wastes" shall mean, without limitation, all waste materials
subject to regulation under CERCLA, RCRA or analogous state law, and/or any
other applicable Federal and/or state law now in force or hereafter enacted
relating to hazardous waste treatment or disposal.

         "Hedging Contracts" shall mean interest rate swap agreements, interest
rate cap agreements and interest rate collar agreements, or any other agreements
or arrangements entered into between any Borrower and the Administrative Agent
or a Lender and designed to protect such Borrower against fluctuations in
interest rates or currency exchange rates.

         "Hedging Obligations" shall mean all liabilities of any and all
Borrowers to the Administrative Agent or a Lender under Hedging Contracts.

         "HMTA" shall mean the Hazardous Materials Transportation Act, as
amended (49 U.S.C. Sections 1801 et seq.)
                                 ------

         "Ineligible Receivables" shall mean Receivables which are (1) evidenced
by a promissory note or similar instrument; (2) owed or payable by an Account
Debtor pursuant to a Commercial Contract, if payment of fifty percent (50%) or
more of the aggregate balance due from such Account Debtor is outstanding for
more than ninety (90) days from the date of original invoice; (3) owed or
payable by an Account Debtor pursuant to a Government Contract, if the payment
of fifty percent (50%) or more of the aggregate balance due from such Account
Debtor is outstanding for more than one hundred twenty (120) days from the date
of original invoice; (4) owing from any person that is the subject of any (a)
suit, lien, levy or judgment which could

                                       10

<PAGE>

reasonably be expected to affect the collectibility of said account(s), or (b)
bankruptcy, insolvency or a similar process or proceeding; (5) owing from
foreign Account Debtors, unless otherwise deemed eligible by the Lenders in
their sole discretion; (6) unbilled as a result of rate variances, retainage
provisions, "milestone" requirements or any other reason, except for timing
differences expressly permitted under the definition of Eligible Unbilled
Government Accounts Receivable; (7) final invoices; or (8) bonded accounts
receivable. Additionally, without limiting any other provision of this
Agreement, or the discretion of the Administrative Agent or the Lenders to deem
Receivables ineligible pursuant to any other provision of this Agreement, it is
expressly understood and agreed that if any Borrower (i) has been debarred or
suspended by the Government, or been issued a notice of proposed debarment or
notice of proposed suspension by the Government; (ii) is the subject of a
Government investigation (other than a normal and customary review by the
Government) involving or possibly involving fraud, willful misconduct or other
wrongdoing, and which could result in criminal liability, liability or expense
in excess of Five Hundred Thousand and No/100 Dollars ($500,000.00), suspension,
debarment or any other adverse administrative action; (iii) is a party to any
Government Contract which has been actually terminated due to such Borrower's
alleged fraud, willful misconduct or any other wrongdoing; (iv) is a party to
any Government Contract which has been actually terminated for any other reason
whatsoever, which could result in liability or expense in excess of Five Hundred
Thousand and No/100 Dollars ($500,000.00); or (v) has been issued a cure notice
or show cause notice under any Government Contract involving amounts in excess
of Five Hundred Thousand and No/100 Dollars ($500,000.00), and has failed to
cure the default giving rise to such cure notice or failed to resolve the matter
set forth in the show cause notice (a) within the time period available to such
Borrower pursuant to such Government Contract and/or such notice, or (b) before
the date on which the Government or other contracting party is entitled to
exercise its rights and remedies under the Government Contract as a consequence
of such default or matter set forth in the show cause notice, then in any such
event, any and all Receivables of such Borrower may, in the sole but reasonable
discretion of the Administrative Agent, be deemed and treated by the Lenders as
Ineligible Receivables.

         "Instrument" shall have the meaning assigned to that term under the
UCC, and shall include any and all of the following, whether now owned or
hereafter acquired and wherever located: all certificates of deposit, and all
"promissory notes", as defined in the UCC, and other evidences of indebtedness,
other than instruments that constitute, or are a part of a group of writings
that constitute, Chattel Paper.

         "Interest Expense" shall mean, as of the date of any determination, the
Borrowers' aggregate cash interest expense for borrowed money (including,
without limitation, premiums and interest expense arising from or relating to
interest rate protection agreements and original issue discounts), plus the
amount of all other interest due (whether paid or not paid) on any indebtedness
of each Borrower for the applicable measurement period, all as determined on a
consolidated basis in accordance with GAAP.

         "Interest Payment Date" shall mean, relative to any LIBOR Rate Loan
having an Interest Period of three months or less, the last Business Day of such
Interest Period, and as to any LIBOR Rate Loan having an Interest Period longer
than three months, each Business Day which is three months, or a whole multiple
thereof, after the first day of such Interest Period and the last day of such
Interest Period.

                                       11

<PAGE>
         "Interest Period" shall mean, relative to any LIBOR Rate Loans, (i)
initially, the period beginning on (and including) the date on which such LIBOR
Rate Loan is made or continued as, or converted into, a LIBOR Rate Loan pursuant
to this Agreement (including, without limitation, Exhibit 3 hereto) and the
                                                  ---------
Notes and ending on (but excluding) the day which numerically corresponds to
such date one, three or six months thereafter (or, if such month has no
numerically corresponding day, on the last Business Day of such month), in each
case as the Borrower may select in its notice pursuant to this Agreement
(including, without limitation, Exhibit 3 hereto) and the Notes; and (ii)
                                ---------
thereafter, each period commencing on the last day of the next preceding
Interest Period applicable to such LIBOR Rate Loan and ending one, three or six
months thereafter, as selected by the Borrower by irrevocable notice to the Bank
not less than two (2) Business Days prior to the last day of the then current
Interest Period with respect thereto.

         "Inventory" shall have the meaning assigned to that term under the UCC,
and shall include any and all of the following, whether now owned or hereafter
acquired and wherever located: all inventory, merchandise, goods and other
personal property for sale or lease or are furnished or are to be furnished
under a contract of service, or that constitute raw materials, work in process,
finished goods, returned goods, or materials or supplies of any kind, nature or
description used or consumed or to be used or consumed or in the processing,
production, packaging, promotion, delivery or shipping of the same, including
all supplies and embedded software.

         "Investment Property" shall have the meaning assigned to that term
under the UCC, and shall include any and all of the following, whether now owned
or hereafter acquired: (a) all securities, whether certificated or
uncertificated, including stocks, bonds, interests in limited liability
companies, partnership interests, treasuries, certificates of deposit, and
mutual fund shares; (b) all Securities Entitlements, including the rights to any
securities account and the financial assets held by a securities intermediary in
such securities account and any free credit balance or other money owing by any
securities intermediary with respect to that account; (c) all securities
accounts; (d) all commodity contracts; and (e) all commodity accounts.

         "Joinder Agreement" shall have the meaning assigned to such term in
Section 1.10 of this Agreement.

         "Lender" and "Lenders" shall mean, respectively, each and all of the
banking or financial institutions which have (i) extended credit to the
Borrowers pursuant to this Agreement, and/or (ii) agreed in writing to be bound
by the terms and provisions of this Agreement.

         "Letter of Credit" and "Letters of Credit" shall mean, respectively,
each and all of the standby letters of credit issued pursuant to this Agreement.

         "Letter of Credit Application" shall have the meaning assigned to such
term in Section 2.1 of this Agreement.

         "Letter of Credit Administration Fee" shall have the meaning assigned
to such term in Section 2.3 of this Agreement.

         "Letter of Credit Fee" shall have the meaning assigned to such term in
Section 2.3 of this Agreement.

                                       12

<PAGE>

         "Letter of Credit Rights" shall have the meaning assigned to that term
under the UCC, and shall include any and all of the following, whether now owned
or hereafter acquired: any right to payment or performance under a letter of
credit, whether or not the beneficiary has demanded or is at the time entitled
to demand payment or performance, but specifically excludes any right of a
beneficiary to demand payment or performance under a letter of credit.

         "LIBOR" or "LIBOR Rate" shall mean relative to any Interest Period for
LIBOR Rate Loans, the offered rate for deposits of U.S. Dollars in an amount
approximately equal to the amount of the requested LIBOR Rate Loan for a term
coextensive with the designated Interest Period which the British Bankers'
Association fixes as its LIBOR rate and which appears on the Telerate Page 3750
as of 11:00 a.m. London time on the day which is two London Banking Days prior
to the beginning of such Interest Period.

         "LIBOR Election Form and Certification" shall mean the form attached as
Exhibit 2 hereto.
---------

         "LIBOR Rate Loan" shall mean any loan or advance, the rate of interest
applicable to which is based upon the LIBOR Rate.

         "LIBOR Lending Rate" shall mean, relative to any LIBOR Rate Loan to be
made, continued or maintained as, or converted into, a LIBOR Rate Loan for any
Interest Period, a rate per annum determined pursuant to the following formula:

            LIBOR Lending Rate          =            LIBOR Rate
                                                     ----------
                                               (1.00 - LIBOR Reserve Percentage)

         "LIBOR Reserve Percentage" shall mean, relative to any day of any
Interest Period for LIBOR Rate Loans, the maximum aggregate (without
duplication) of the rates (expressed as a decimal fraction) of reserve
requirements (including all basic, emergency, supplemental, marginal and other
reserves and taking into account any transitional adjustments or other scheduled
changes in reserve requirements) under any regulations of the Board of Governors
of the Federal Reserve System (the "Board") or other governmental authority
having jurisdiction with respect thereto as issued from time to time and then
applicable to assets or liabilities consisting of "Eurocurrency Liabilities", as
currently defined in Regulation D of the Board, having a term approximately
equal or comparable to such Interest Period.

         "Loan" shall mean the loans made by the Lenders to the Borrowers in the
aggregate maximum principal amount of Seventy-one Million Four Hundred Thousand
and No/100 Dollars ($71,400,000.00), or so much thereof as shall be advanced or
readvanced from time to time, which are represented by the Facilities, and which
shall be evidenced by, bear interest and be payable in accordance with the terms
and provisions set forth in the Notes.

         "Loan Document" and "Loan Documents" shall mean, respectively, each and
all of this Agreement, the Notes, the Stock Security Agreements and each other
document, instrument, agreement or certificate heretofore, now or hereafter
executed and delivered by any Borrower in connection with the Loan.

         "London Banking Day" shall mean a day on which dealings in US dollar
deposits are transacted in the London interbank market.

                                       13

<PAGE>

         "Mandatory Payments" shall mean the mandatory payments required to be
made on the Loan pursuant to Section 1.5 of this Agreement.

         "ManTech Europe" shall have the meaning assigned to such term in
Section 3.1 of this Agreement.

         "Material Contract" shall mean any and all Government Contracts and/or
other contracts or agreements of any Borrower(s) involving amounts, in the
aggregate, in excess of the Dollar Equivalent Amount of Five Million and No/100
Dollars ($5,000,000.00).

         "Maturity Date" shall mean December 31, 2004 or such other date as may
be agreed to by the Administrative Agent, the Lenders and the Borrowers in
writing.

         "Maximum Borrowing Base" shall have the meaning assigned to such term
in Section 1.3 of this Agreement.

         "Net Cash" shall mean cash proceeds (net of cash taxes paid and
reasonable and customary costs paid to unrelated and unaffiliated third parties
in connection with a particular transaction) arising from any Excess Cash Event.

         "Note" and "Notes" shall mean, respectively, each and all of the
promissory notes executed, issued and delivered pursuant to this Agreement,
together with all extensions, renewals, modifications, replacements and
substitutions thereof and therefor.

         "NSI" shall mean NSI Technology Services Corporation, a California
corporation, together with its successors and assigns.

         "Obligation" and "Obligations" shall mean, respectively, any and all
obligations or liabilities of any Borrower to any Lender or any Agent in
connection with the Loan, whether now existing or hereafter created or arising,
direct or indirect, matured or unmatured, and whether absolute or contingent,
joint, several or joint and several, and no matter how the same may be evidenced
or shall arise.

         "Ordinary Course Payments" shall mean payments made directly by a
Borrower to any non-Borrower subsidiary or affiliate; provided that that such
payments are made (i) in the ordinary course of such Borrower's business, (ii)
for products actually delivered or services actually performed, and (iii)
pursuant to an "arm's length" transaction (i.e., a transaction that would
otherwise be made with an unrelated and unaffiliated third party).

         "Parent Company" shall mean ManTech International Corporation, a New
Jersey corporation, together with its successors and assigns.

         "Pedersen" shall mean George J. Pedersen, during his life as long as he
is legally competent, and thereafter Marilyn Pedersen during her life as long as
she is legally competent, and thereafter the Pedersen Family Trust.

         "Pedersen Entity" shall mean any entity in which Pedersen owns and
holds at least fifty-one percent (51%) of the voting stock (and has both
majority and effective control).

                                       14

<PAGE>

         "Pension Plan" or "Pension Plans" shall have the meaning assigned to
such term in Section 5.13(a) of this Agreement.

         "Percentage" shall mean with respect to each Lender, the percentage set
forth below such Lender's name on Schedule 1 to this Agreement in respect of the
                                  ----------
Commitment Amount, the Facility A Commitment Amount, the Facility B Commitment
Amount and/or the Swing Line Commitment Amount (as the context may require), as
the same may be modified or amended from time to time.

         "Permitted Liens" shall mean: (a) liens for taxes which are being
contested in good faith and by appropriate proceedings, which (i) the Borrower
has the financial ability to pay, including penalties and interest, and (ii) the
non-payment thereof will not result in the execution of any such tax lien or
otherwise jeopardize the interests of the Administrative Agent and/or the
Lenders in any part of the Collateral; (b) deposits or pledges to secure
obligations under workers' compensation, social security or similar laws,
incurred in the ordinary course of business; (c) liens securing indebtedness of
the Borrowers permitted by Section 7.7 of this Agreement; (d) cash deposits
pledged to secure the performance of bids, tenders, contracts (other than
contracts for the payment of money), leases, statutory obligations, surety and
appeal bonds and other obligations of like nature made in the ordinary course of
business; (e) mechanics', workmen's, repairmen's, warehousemen's, vendors' or
carriers' liens or other similar liens; provided that such liens arise in the
ordinary course of the Borrowers' business and secure sums which are not past
due, or which are separately secured by cash deposits or pledges in an amount
adequate to obtain the release of such liens; (f) except as otherwise provided
in this Agreement, statutory or contractual landlord's liens on the Borrower's
tangible personal property located in the demised premises; (g) zoning or other
similar and customary land use restrictions, which do not materially impair the
use or value of the subject property; (h) judgment liens which are not
prohibited by Section 7.4 of this Agreement; (i) other liens expressly permitted
by the terms and provisions of this Agreement; and (j) liens in favor of the
Administrative Agent.

         "Permitted Offering" shall have the meaning assigned to that term in
Section 1.5 of this Agreement.

         "PNC" shall mean PNC Bank, National Association, a national banking
association, acting individually, together with its successors and assigns.

         "Praxa" shall mean Praxa Limited, a company organized and existing
under the laws of the Commonwealth of Australia.

         "Prime Rate" shall mean the rate of interest from time to time
established and publicly announced by Citizens Bank as its prime rate, in
Citizens Bank's sole discretion, which rate of interest may be greater or less
than other interest rates charged by Citizens Bank to other borrowers and is not
solely based or dependent upon the interest rate which Citizens Bank may charge
any particular borrower or class of borrowers.

         "Proceeds" shall have the meaning assigned to that term under the UCC
or under other applicable law, and, in any event, shall include, but shall not
be limited to, any and all of the following, whether now owned or hereafter
acquired: (i) any and all proceeds of, or amounts (in any form whatsoever,
whether cash, securities, property or other assets) received under or

                                       15

<PAGE>

with respect to, any insurance, indemnity, warranty or guaranty payable from
time to time, and claims for insurance, indemnity, warranty or guaranty effected
or held with respect to any of the Collateral, (ii) any and all payments (in any
form whatsoever, whether cash, securities, property or other assets) made or due
and payable from time to time in connection with any requisition, confiscation,
condemnation, seizure or forfeiture of all or any part of the Collateral by any
governmental authority (or any person acting under color of governmental
authority), (iii) any claim against third parties (a) for past, present or
future infringement of any patent or patent license, or (b) for past, present or
future infringement or dilution of any copyright, copyright license, trademark
or trademark license, or for injury to the goodwill associated with any
trademark or trademark license, (iv) any recoveries against third parties with
respect to any litigation or dispute concerning any of the Collateral including
claims arising out of the loss or nonconformity of, interference with the use
of, defects in, or infringement of rights in, or damage to, Collateral, (v) all
amounts collected on, or distributed on account of, other Collateral, including
dividends, interest, distributions and Instruments with respect to Investment
Property and pledged stock, and (vi) any and all other amounts (in any form
whatsoever, whether cash, securities, property or other assets) from time to
time paid or payable under or in connection with any of the Collateral (whether
or not in connection with the sale, lease, license, exchange or other
disposition of the Collateral).

         "RCRA" shall mean the Resource Conservation and Recovery Act, as
amended (42 U.S.C. Sections 6901 et. seq.).
                                 --- ---

         "Receivables" shall mean all of the Borrowers' present and future
accounts, contracts, contract rights, chattel paper, general intangibles, notes,
drafts, acceptances, chattel mortgages, conditional sale contracts, bailment
leases, security agreements, contribution rights and other forms of obligations
now or hereafter arising out of or acquired in the course of or in connection
with any business the Borrowers conduct, together with all liens, guaranties,
securities, rights, remedies and privileges pertaining to any of the foregoing,
whether now existing or hereafter created or arising, and all rights with
respect to returned and repossessed items of inventory.

         "Request for Advance and Certification" shall mean the form Request for
Advance and Certification attached as Exhibit 1 hereto.
                                      ---------

         "Required Lenders" shall mean all of the Lenders who at any given time,
are not in default under or in breach of any of the terms and conditions of this
Agreement applicable to such Lender, and who hold Notes or participation
interests representing, in the aggregate, at least fifty-one percent (51%) of
the aggregate Commitment Amount (excluding the Swing Line Commitment Amount).

         "Restructuring Fee" shall have the meaning assigned to such term in
Section 1.7(a) of this Agreement.

         "Revolver Notes" shall mean each and all of the promissory notes
executed, issued and delivered pursuant to this Agreement in connection with
Facility A, together with all extensions, renewals, modifications, replacements
and substitutions thereof and therefor.

                                       16

<PAGE>

         "Security Entitlements" shall have the meaning to that term under the
UCC, and shall include any and all Security Entitlements whether now owned or
hereafter created or acquired.

         "Stock Security Agreements" shall mean each and all of the following
documents, instruments and agreements: (a) Stock Security Agreement dated the
date hereof, by and between the Parent Company and the Administrative Agent, (b)
MAI Stock Security Agreement dated the date hereof between the Administrative
Agent and ManTech Australia International, Inc., (c) ManTech U.K. Systems
Corporation Stock Security Agreement dated the date hereof, between the
Administrative Agent and ManTech U.K. Systems Corporation, (d) any and all stock
security agreements now or hereafter executed and delivered by a Borrower as
security for repayment of the Loan, and (e) any and all amendments and/or
modifications of any of the foregoing stock security agreements.

         "Supporting Obligations" shall have the meaning assigned to that term
under the UCC, and shall include any and all of the following, whether now owned
or hereafter acquired: any and all letter of credit rights or secondary
obligations that support the payment or performance of an Account, Chattel
Paper, Document, General Intangible, Instrument or Investment Property.

         "Swing Line Commitment" shall mean the Swing Line Lender's obligation
to make Swing Line Loans to the Borrowers in the aggregate principal amount not
to exceed Ten Million and No/100 Dollars ($10,000,000.00).

         "Swing Line Commitment Amount" shall mean Ten Million and No/100
Dollars ($10,000,000.00).

         "Swing Line Commitment Period" shall mean the period commencing on the
Closing Date and ending on the Swing Line Termination Date.

         "Swing Line Facility" shall mean the swing line credit facility being
extended pursuant to this Agreement, in the original maximum principal amount
equal to the Swing Line Commitment Amount.

         "Swing Line Lender" shall mean Citizens Bank.

         "Swing Line Loan" or "Swing Line Loans" shall have the meaning
attributed to such term in Section 1.1(b) of this Agreement.

         "Swing Line Note" shall mean that certain Swing Line Promissory Note of
even date herewith, made by the Borrowers and payable to the order of the Swing
Line Lender, in the maximum principal amount of Ten Million and No/100 Dollars
($10,000,000.00) or so much thereof as shall be advanced, together with all
extensions, renewals, modifications, replacements and substitutions thereof or
therefor.

         "Swing Line Outstandings" shall mean, as of any date of determination,
the aggregate principal amount of all Swing Line Loans then outstanding.

                                       17

<PAGE>

         "Swing Line Termination Date" shall mean the fifth (5/th/) Business Day
prior to the Maturity Date, or such earlier date on which the Swing Line Lender
has elected, in its sole and absolute discretion, to terminate the Swing Line
Facility.

         "Total Debt" shall mean the actual amount of borrowed money (including,
without limitation, subordinated debt, capital leases and synthetic leases that
remain unpaid or outstanding as of the date of any determination), plus the
aggregate amount of any and all financial guarantees and the face amount of any
and all outstanding letters of credit, less cash-on-hand; it being understood
and agreed that trade debt incurred in the ordinary course of the Borrower's
business shall not be included in the computation of Total Debt.

         "UCC" shall mean the Uniform Commercial Code as the same may, from time
to time, be enacted and in effect in the Commonwealth of Virginia; provided,
                                                                   --------
that to the extent that the UCC is used to define any term herein and such term
is defined differently in different Articles or Divisions of the UCC, the
definition of such term contained in Article or Division 9 shall govern;
provided further, that in the event that, by reason of mandatory provisions of
----------------
law, any or all of the attachment, perfection or priority of, or remedies with
respect to, the Administrative Agent's lien on any Collateral is governed by the
Uniform Commercial Code as enacted and in effect in a jurisdiction other than
the Commonwealth of Virginia, the term "UCC" shall mean the Uniform Commercial
Code as enacted and in effect in such other jurisdiction solely for purposes of
the provisions thereof relating to such attachment, perfection, priority or
remedies and for purposes of definitions related to such provisions.

         "Vobix" shall mean Vobix Corporation, a Virginia corporation.

                                   ARTICLE 1
                                   COMMITMENT

         1.1. Maximum Loan Amount.
              -------------------

              (a) Subject to the terms and conditions of this Agreement, (i)
each Lender severally agrees to make the Loan to the Borrowers (except for the
Swing Line Loan, which shall be extended only by the Swing Line Lender), with
the maximum amount of each Lender's obligation being equal to the Lender's
Percentage of the Commitment Amount; and (ii) as set forth more fully in Section
1.1(b) below, the Swing Line Lender will make the Swing Line Loan to the
Borrowers. The Loan, including the Swing Line Loan, shall bear interest and be
payable in accordance with the terms and provisions of and be initially
evidenced by nine (9) promissory notes, four (4) of which shall evidence
Facility A, four (4) of which shall evidence Facility B and one (1) of which
shall evidence the Swing Line Facility. Concurrent with the Borrowers' execution
of this Agreement, (a) Citizens Bank shall receive a revolving promissory note
in the maximum principal amount of Twenty-four Million Three Hundred
Seventy-five Thousand and No/100 Dollars ($24,375,000.00) or so much thereof as
shall be advanced or readvanced, a term promissory note in the original
principal amount of Two Million Four Hundred Thousand and No/100 Dollars
($2,400,000.00) and the Swing Line Note, (b) PNC shall receive a revolving
promissory note in the maximum principal amount of Sixteen Million Two Hundred
Fifty Thousand and No/100 Dollars ($16,250,000.00) or so much thereof as shall
be advanced or readvanced, and a term promissory note in the original principal
amount of One Million Six

                                       18

<PAGE>

Hundred Thousand and No/100 Dollars ($1,600,000.00), (c) BB&T shall receive a
revolving promissory note in the maximum principal amount of Twelve Million Five
Hundred Seventeen Thousand Five Hundred Seven and No/100 Dollars
($12,517,507.00) or so much thereof as shall be advanced or readvanced, and a
term promissory note in the original principal amount of One Million Two Hundred
Thirty-two Thousand Four Hundred Ninety-three and No/100 Dollars
($1,232,493.00), and (d) Chevy Chase shall receive a revolving promissory note
in the maximum principal amount of Eleven Million Eight Hundred Fifty-seven
Thousand Four Hundred Ninety-three and No/100 Dollars ($11,857,493.00) or so
much thereof as shall be advanced or readvanced, and a term promissory note in
the original principal amount of One Million One Hundred Sixty-seven Thousand
Five Hundred Seven and No/100 Dollars ($1,167,507.00);

              (b) Subject to the terms and conditions of this Agreement, the
Swing Line Lender shall make swing line loans (each, a "Swing Line Loan" and
collectively, the "Swing Line Loans") to the Borrowers from time to time during
the Swing Line Commitment Period, in the aggregate principal amount at any one
time outstanding not to exceed Ten Million and No/100 Dollars ($10,000,000.00);
provided, however, that at no time may the aggregate outstanding principal
amount of the Swing Line Loans, plus the aggregate outstanding principal amount
of Facility A (including the aggregate face amount of all Letters of Credit
outstanding), plus the Dollar Equivalent Amount of the Duty Deferment Bond
exceed the lesser of the Facility A Commitment Amount, and the applicable
Maximum Borrowing Base. During the Swing Line Commitment Period, the Borrowers
may use the Swing Line Commitment by borrowing, repaying Swing Line Loans in
whole or in part, and reborrowing, all in accordance with the terms of this
Agreement. At the request of the Swing Line Lender, the Administrative Agent
may, at any time, on behalf of the Borrowers (which hereby irrevocably direct
the Administrative Agent to act on their behalf) request each Lender having a
Percentage of Facility A, including the Swing Line Lender, to make, and each
such Lender, including the Swing Line Lender, shall make an advance under
Facility A, in an amount equal to such Lender's Percentage of Facility A, of the
amount of the Swing Line Outstandings as of the date such request is made. In
such event, each such Lender shall make the requested proceeds available to the
Administrative Agent for the account of the Swing Line Lender in accordance with
the funding provisions set forth in this Agreement. The proceeds of Facility A
advanced pursuant to this Section 1.1(b) shall be immediately applied to repay
the Swing Line Outstandings.

         1.2. Use of Proceeds. The Loan shall be used by the Borrowers only for
              ---------------
the following purposes: (i) to refinance certain existing indebtedness of the
Borrowers; and (ii) for working capital and general corporate needs. Each
Borrower agrees that it will not use or permit the Loan proceeds to be used for
any other purpose without the prior written consent of the Administrative Agent.

         1.3. Borrowing Base and Maximum Advances. Notwithstanding any term or
              -----------------------------------
provision of this Agreement or any other Loan Document to the contrary, it is
understood and agreed that in no event whatsoever shall the Lenders be obligated
to advance any amount or issue any Letters of Credit hereunder if such advance
or the issuance of such Letter of Credit would cause the aggregate amount of
outstanding Loans (including Swing Line Outstandings), plus the face amount of
all outstanding Letters of Credit, plus the Dollar Equivalent Amount of the Duty
Deferment Bond, to exceed the following amounts:

                                       19

<PAGE>

              (a) as to Facility A, the lesser of:

                     (i)   the Facility A Commitment Amount; or

                     (ii)  the aggregate of (the "Maximum Borrowing Base"):

                           A.     Ninety percent (90%) of Eligible Billed
                                  Government Accounts Receivable, which are
                                  outstanding less than one hundred twenty-one
                                  (121) days from the date of original invoice;
                                  plus

                           B.     Eighty-five percent (85%) of Eligible Billed
                                  Commercial Accounts Receivable, which are
                                  outstanding less than ninety-one (91) days
                                  from the date of original invoice; plus

                           C.     the lesser of (I) Ten Million Dollars
                                  ($10,000,000), or (II) fifty percent (50%) of
                                  Eligible Unbilled Government Accounts
                                  Receivable; plus

                           D.     the lesser of (I) sixty percent (60%) of the
                                  Dollar Equivalent Amount of Eligible ARL
                                  Receivables which are outstanding less than
                                  ninety-one (91) days from the date of original
                                  invoice; or (II) One Million and No/100
                                  Dollars ($1,000,000.00).

                                  Notwithstanding anything to the contrary set
                                  forth herein, it is expressly understood and
                                  agreed that in no event whatsoever shall the
                                  aggregate Dollar Equivalent Amount of
                                  outstanding loans to ARL and Vobix at any time
                                  exceed Six Million and No/100 Dollars
                                  ($6,000,000.00) and Ten Million and No/100
                                  Dollars ($10,000,000.00), respectively.

              (b) as to Facility B, the Facility B Commitment Amount; and

              (c) as to the Swing Line Facility, the lesser of the Swing Line
Facility Commitment Amount or the Maximum Borrowing Base.

All determinations regarding eligibility shall be made by the Lenders.
Determinations regarding eligibility of billed and unbilled Receivables shall be
made in the reasonable discretion of the Administrative Agent; provided,
however, that in the event of any dispute or disagreement as to whether an
unbilled Receivable is, or has ceased to be, eligible pursuant to the terms of
this Agreement, the decision of the Administrative Agent in the exercise of its
sole and absolute discretion shall control.

If at any time the outstanding principal balance of Facility A (including the
maximum aggregate face amount of all outstanding Letters of Credit, plus Swing
Line Outstandings, plus the Dollar

                                       20

<PAGE>

Equivalent Amount of the Duty Deferment Bond) exceeds the Maximum Borrowing Base
(such excess being referred to herein as a "Borrowing Base Deficiency"), the
Borrowers shall immediately make a principal payment in the amount of the
Borrowing Base Deficiency; it being expressly understood and agreed that, for
purposes of calculating the Maximum Borrowing Base with respect to Eligible ARL
Accounts Receivable and the Duty Deferment Bond, the Dollar Equivalent Amount
shall be determined as of the date of the applicable Borrowing Base/Non-Default
Certificate.

         1.4. Advances.
              --------

              (a) Agreement to Advance and Readvance; Procedure. So long as no
                  ---------------------------------------------
Event of Default shall have occurred and be continuing, and no act, event or
condition shall have occurred and be continuing which with notice or the lapse
of time, or both, shall constitute an Event of Default, and subject to the terms
and provisions of this Agreement, the Lenders (and the Swing Line Lender, as the
case may be) shall (i) advance and readvance the proceeds of Facility A and the
proceeds of the Swing Line Facility from time to time in accordance with this
Agreement; and (ii) advance the proceeds of Facility B to the Borrowers upon the
Borrowers' execution and delivery of this Agreement and all other documents,
instruments and agreements required by the Lenders in connection herewith.
Requests for advances with respect to Facility A shall be in the form of Exhibit
                                                                         -------
1 hereto, and requests for advances with respect to the Swing Line Facility
-
shall be in the form of Exhibit 1(a) hereto. Requests for advances of Loan
                        ------------
proceeds with respect to Facility A and the Swing Line Facility may be made via
facsimile on any given Business Day if the Borrowers provide the Administrative
Agent, in advance, with a written list of the names of the specific officers
authorized to request disbursements by facsimile. Upon request by the
Administrative Agent, the Borrowers shall confirm in an original writing each
facsimile request for advance made by any Borrower. Notwithstanding the
foregoing, (a) the Lenders shall have no obligation to make any advance with
respect to Facility A after the Maturity Date; and (b) the Swing Line Lender
shall have no obligation to make any advance with respect to the Swing Line
Facility after the Swing Line Termination Date.

              (b) Interest Rate Election; Certain Advance Procedures and Limits.
                  -------------------------------------------------------------
Amounts advanced in connection with the Loan shall bear interest either on a
Base Rate basis or LIBOR basis, as more fully set forth in the Notes in the
exhibits attached to this Agreement, except that the Swing Line Loans shall only
be made available to the Borrowers on a Base Rate basis. Advances bearing
interest on a Base Rate basis shall be in minimum and incremental amounts of One
Hundred Thousand Dollars ($100,000.00), and shall be made available on a
same-day basis, if requested by 12:00 Noon Washington, D.C. time on a Business
Day. Advances bearing interest on a LIBOR basis shall also be in minimum and
incremental amounts of One Hundred Thousand Dollars ($100,000.00), and shall be
made available not less than two (2) Business Days nor more than five (5)
Business Days after request therefor. The Borrowers' right to request LIBOR
based interest, as well as certain additional terms, conditions and requirements
relating thereto, are set forth in the Notes and in the exhibits attached to
this Agreement, and each Borrower expressly acknowledges and consents to such
additional terms and provisions.

         1.5. Additional Mandatory Payments; Reduction of Commitment. In
              ------------------------------------------------------
addition to all other sums payable by the Borrowers pursuant to any of the
Notes, this Agreement or any other Loan Document, the Borrowers shall also make
mandatory payments on the Notes (applied

                                       21

<PAGE>

first to amounts outstanding under Facility B, then to Swing Line Outstandings
(if any), and then to amounts outstanding under Facility A, as provided herein
below), upon the occurrence of any Excess Cash Event. Notwithstanding the
foregoing, no mandatory payment shall be due and payable unless the Net Cash
arising from any Excess Cash Event occurring in any fiscal year, when aggregated
with all other Excess Cash Events occurring during fiscal year, exceeds the
Annual Excess Cash Limitation, in which event the amount of such mandatory
payment shall be equal to the amount by which the Net Cash arising from such
Excess Cash Event exceeds the Annual Excess Cash Limitation. In the event any
payment(s) made or required to be made by the Borrowers pursuant to this Section
1.5 shall be applied to Facility A (i.e., all amounts outstanding under Facility
B and Swing Line Outstandings (if any) shall have been paid and satisfied in
full), the Facility A Commitment Amount shall be reduced by an amount equal to
such payment; provided, however, that no such reduction in the Facility A
Commitment Amount shall occur until the aggregate amount of such mandatory
payments during any fiscal year exceeds Two Million and No/100 Dollars
($2,000,000.00) or the aggregate amount of such mandatory payments during the
loan term exceeds Five Million Five Hundred Thousand and No/100 Dollars
($5,500,000.00), whichever occurs first, in which event the Facility A
Commitment Amount shall only be reduced to the extent the aggregate amount of
such mandatory payments during such fiscal year exceeds Two Million and No/100
Dollars ($2,000,000.00) or to the extent the amount of such mandatory payments
during the loan term exceeds Five Million Five Hundred Thousand and No/100
Dollars ($5,500,000.00), as applicable. Furthermore, in the event that any
Borrower issues additional equity interests or capital stock in accordance with
Section 7.1(a) of this Agreement (a "Permitted Offering") and the Net Cash
thereof shall have been used to pay and satisfy in full all amounts outstanding
under Facility B and Swing Line Outstandings (if any), then so long as no Event
of Default shall have occurred and be continuing beyond any applicable notice
and cure period (i) any remaining Net Cash of the Permitted Offering may be used
by the Borrowers to repay the First Source Debt in full before having to apply
remaining Net Cash of the Permitted Offering to amounts outstanding under
Facility A, (ii) the Borrowers shall not be obligated to make any mandatory
payment on amounts then outstanding under Facility A unless, at the time of the
Permitted Offering, the then outstanding principal balance of Facility A exceeds
Twenty-five Million and No/100 Dollars ($25,000,000.00), in which event the
mandatory payment shall be in an amount equal to such excess, and (iii) to the
extent any remaining Net Cash of the Permitted Offering shall be applied to
amounts outstanding under Facility A pursuant to this Section 1.5, no such
reduction in the Facility A Commitment Amount shall be required.

         1.6. Field Audits. The Administrative Agent has the right at any time
              ------------
and in its sole discretion to conduct field audits with respect to the
Collateral and each Borrower's accounts receivable, inventory, business and
operations. All field audits shall be at the cost and expense of the Borrowers;
it being understood and agreed that, in the absence of an Event of Default, the
Borrowers' maximum liability for field audit costs and expenses shall be limited
to the costs and expenses of only one (1) field audit conducted during any
twelve (12) month period (unless the Administrative Agent shall conduct a field
audit pursuant to Section 1.10 of this Agreement in connection with the joinder
of a new "Borrower" hereunder, in which event the Borrowers shall be liable for
the costs and expenses of such field audit as well). Any and all field audits
conducted following an Event of Default shall be at the Borrowers' cost and
expense, with the foregoing limitation on maximum costs and expense being
inapplicable.

                                       22

<PAGE>

         1.7. Certain Fees. In addition to principal, interest and other sums
              ------------
payable under the Notes, the Borrowers shall pay the following fees:

              (a) Restructuring Fee. Simultaneously with the execution of this
                  -----------------
Agreement, the Borrowers shall pay to the Administrative Agent, for the benefit
of all Lenders pro-rata based on each Lender's Percentage, a Loan restructuring
fee (the "Restructuring Fee") in the aggregate amount of Three Hundred
Fifty-seven Thousand and No/100 Dollars ($357,000.00).

              (b) Commitment Fee. So long as any amounts remain outstanding in
                  --------------
connection with the Facility, or the Lenders have any obligation to make any
advance in connection therewith, the Borrowers agree to pay to the
Administrative Agent for the benefit of all Lenders pro-rata based on each
Lender's Percentage, a quarter-annual commitment fee (the "Facility A Commitment
Fee"), at the annual rate corresponding to the Borrower's Total Debt to EBITDA
ratio for the immediately preceding quarter, as set forth on Exhibit 9 hereto,
                                                             ---------
calculated on the difference between (i) the Facility A Commitment Amount, and
(ii) the sum of the average daily outstanding principal balance of Facility A
and the Swing Line Facility during the applicable quarter, plus the aggregate
face amount of all outstanding Letters of Credit during the applicable quarter,
plus the Dollar Equivalent of the Duty Deferment Bond (determined as of the date
of the most recently submitted Borrowing Base/Non-Default Certificate). The
Facility A Commitment Fee shall be calculated on the basis of the actual number
of days elapsed and a three hundred sixty (360) day year, shall be due for any
quarter during which the Lenders have any obligation in connection with the
Facility, and shall be payable in arrears, commencing on December 31, 2001 and
continuing on the last Business Day of every third (3rd) calendar month
thereafter for so long as this Agreement remains in effect.

              (c) Administrative Agent Fee. The Borrowers shall pay to the
                  ------------------------
Administrative Agent, for its own account, a loan administration fee (the
"Administration Fee"), in the amount of Fifty Thousand and No/100 Dollars
($50,000.00) per annum. The Administration Fee shall be due and payable in full
on the date of this Agreement and on each anniversary of the date of this
Agreement.

              (d) Letter of Credit Fees. The Borrowers shall pay any and all
                  ---------------------
Letter of Credit fees as and when such fees become due and payable pursuant to
this Agreement.

              (e) Out-of-Pocket Fees and Expenses. The Borrowers shall be liable
                  -------------------------------
for and shall timely pay all reasonable out-of-pocket costs and expenses
(including reasonable attorneys' fees and expenses of counsel for the
Administrative Agent, and of other special and local counsel and other experts,
if any, engaged by the Administrative Agent) from time to time incurred by the
Administrative Agent in connection with the administration of, preservation of
rights in and enforcement of this Agreement, the other Loan Documents and the
transactions contemplated by this Agreement. Without limiting the generality of
the foregoing, the Borrowers shall be liable for all reasonable out-of-pocket
costs and expenses associated with any and all amendments, waivers and/or
consents relating to any of the Facilities.

         1.8. Intentionally Omitted.
              ---------------------

                                       23

<PAGE>

         1.9. Appointment of the Parent Company. Each Borrower acknowledges that
              ---------------------------------
(i) the Lenders have agreed to extend credit to each of the Borrowers on an
integrated basis for the purposes herein set forth; (ii) it is receiving direct
and/or indirect benefits from each such extension of credit; and (iii) the
obligations of the "Borrower" or "Borrowers" under this Agreement are the joint
and several obligations of each Borrower. To facilitate the administration of
the Loan, each Borrower hereby irrevocably appoints the Parent Company as its
true and lawful agent and attorney-in-fact with full power and authority to
execute, deliver and acknowledge on such Borrower's behalf, each Request for
Advance and Certification, Borrowing Base/Non-Default Certificate and all other
Loan Documents or other materials provided or to be provided to any of the
Agents or Lenders pursuant to this Agreement or in connection with the Loan.
This power-of-attorney is coupled with an interest and cannot be revoked,
modified or amended without the prior written consent of the Administrative
Agent. Upon request of the Administrative Agent, each Borrower shall execute,
acknowledge and deliver to the Administrative Agent a form Power of Attorney
confirming and restating the power-of-attorney granted herein.

         1.10. Joinder of New Subsidiaries and Affiliates. Any present or future
               ------------------------------------------
subsidiary of any Borrower in which such Borrower now or hereafter owns,
directly or indirectly, an ownership interest of greater than fifty percent
(50%) shall, unless waived in writing by the Administrative Agent, execute and
deliver to the Administrative Agent (a) a Joinder Agreement in the form attached
hereto as Exhibit 6 (a "Joinder Agreement"), pursuant to which such subsidiary
          ---------
or affiliate shall (i) join in and become a party to this Agreement and the
other Loan Documents; (ii) agree to comply with and be bound by the terms and
conditions of this Agreement and all of the other Loan Documents; and (iii)
become a "Borrower" and thereafter be jointly and severally liable for the
performance of all the past, present and future obligations and liabilities of
the Borrowers hereunder and under the Loan Documents; and (b) such other
documents, instruments and agreements as may be reasonably required by the
Administrative Agent in connection therewith (including, without limitation, an
opinion of counsel), in form and substance acceptable to the Administrative
Agent in all respects. The Borrowers acknowledge and agree that the
Administrative Agent shall have the right, at the Borrowers' cost and expense,
to perform a field audit of the accounts receivable, inventory, business and
operations of any present or future subsidiary or affiliate proposed to be
joined as a "Borrower" hereunder.

                                   ARTICLE 2
                                LETTERS OF CREDIT

         2.1. Issuance. The Borrowers and Lenders acknowledge that from time to
              --------
time the Borrowers may request that Citizens Bank issue or amend Letter(s) of
Credit. Subject to the terms and conditions of this Agreement, and any other
reasonable requirements for letters of credit normally and customarily imposed
by Citizens Bank, Citizens Bank agrees to issue such requested letters of
credit, provided that no Event of Default has occurred and is continuing, and no
act, event or condition which with notice or the passage of time, or both, would
constitute an Event of Default has occurred and is continuing. If any such
Letter(s) of Credit are issued by Citizens Bank, each of the Lenders shall
purchase from Citizens Bank a risk participation with respect to such Letter(s)
of Credit in an amount equal to such Lender's Percentage of such Letter(s) of
Credit. Citizens Bank shall have no obligation to issue any Letter of Credit
which

                                       24

<PAGE>

has an expiration date beyond the Maturity Date, unless the Borrowers shall have
deposited with the Administrative Agent, concurrent with the issuance of any
such Letter of Credit, cash security therefor in an amount equal to the face
amount of the Letter of Credit. Any request for a Letter of Credit shall be made
by a Borrower submitting to the Administrative Agent an Application and
Agreement for Letter of Credit or Amendment to Letter of Credit (each being
herein referred to as a "Letter of Credit Application") on Citizens Bank's
standard form, at least three (3) Business Days prior to the date on which the
issuance or amendment of the Letter of Credit shall be required, which Letter of
Credit Application shall be executed by an authorized officer of a Borrower, and
be accompanied by such other supporting documentation and information as the
Administrative Agent may from time to time reasonably request. Each Letter of
Credit Application shall be deemed to govern the terms of issuance of the
subject Letter of Credit, except to the extent inconsistent with the terms of
this Agreement. It is understood and agreed that Letters of Credit shall not be
issued for durations of longer than one (1) year. Any outstanding Letter of
Credit may be renewed from time to time; provided that (i) at least sixty (60)
days' prior written notice thereof shall have been given by the Borrower to the
Administrative Agent; and (ii) no default or Event of Default exists under the
terms and provisions of the particular Letter of Credit or this Agreement.
Letters of Credit issued pursuant to this Agreement may be issued in U.S.
Dollars, Australian Dollars or such other foreign currency as the Administrative
Agent may approve.

         2.2. Amounts Advanced Pursuant to Letters of Credit. Upon the issuance
              ----------------------------------------------
of any Letter(s) of Credit (i) any amounts drawn under any Letter of Credit
shall be deemed advanced ratably under the Revolver Notes, shall bear interest
and be payable in accordance with the terms of the Revolver Notes and shall be
secured by the Collateral (in the same manner as all other sums advanced under
the Revolver Notes); and (ii) each Lender shall purchase from Citizens Bank such
risk participations in the Letter(s) of Credit as shall be necessary to cause
each Lender to share the funding obligations with respect thereto ratably in
accordance with its particular Percentage. It is expressly understood and agreed
that all obligations and liabilities of the Borrowers to Citizens Bank in
connection with any such Letter(s) of Credit shall be deemed to be
"Obligations," and the Administrative Agent shall not be required to release its
security interest in the Collateral until (i) all Notes and all other sums due
to the Lenders in connection with the Loan have been paid and satisfied in full,
(ii) all Letters of Credit have been canceled or expired, and (iii) no Lender
has any further obligation or responsibility to make additional Loan advances or
issue additional Letters of Credit. Furthermore, in no event whatsoever shall
Citizens Bank have any obligation to issue any Letter of Credit which would
cause the face amount of all then outstanding Letters of Credit issued for the
benefit of any or all Borrowers, in the aggregate, to exceed the Dollar
Equivalent Amount of Ten Million and No/100 Dollars ($10,000,000.00), at any
time.

         2.3. Letter of Credit Fees. The Borrowers shall be jointly and
              ---------------------
severally liable for the payment of: (i) to the Lenders ratably, a per annum fee
in the amount of one and three-quarters percent (1.75%) of the Dollar Equivalent
Amount of the average daily undrawn amount of each Letter of Credit issued or
amended pursuant to this Agreement (the "Letter of Credit Fee"), calculated on
the basis of the actual number of days elapsed and a three hundred sixty (360)
day year; and (ii) to the Administrative Agent, customary issuance and
administrative charges (the "Letter of Credit Administration Fee"). The Letter
of Credit Fee shall be due and payable, in advance, on the date the Letter of
Credit is issued or amended, and on the same day

                                       25

<PAGE>

of every third (3rd) month thereafter during which such Letter of Credit shall
remain issued or outstanding. The Letter of Credit Administration Fee shall be
due and payable simultaneously with the Administrative Agent's issuance or
amendment of the particular Letter of Credit.

                                   ARTICLE 3
                                    SECURITY

         3.1. Security Generally. As collateral security for the Loan and all
              ------------------
other Obligations, the Borrowers hereby grant and convey to the Administrative
Agent, for the benefit of all of the Lenders ratably, a security interest in all
of the following (collectively, the "Collateral"):

              Receivables. All of each Borrower's present and future Accounts,
              -----------
              contracts, contract rights, Chattel Paper, General Intangibles,
              notes, drafts, acceptances, chattel mortgages, conditional sale
              contracts, bailment leases, security agreements and other forms of
              obligations now or hereafter arising out of or acquired in the
              course of or in connection with any business each Borrower
              conducts, together with all liens, guaranties, securities, rights,
              remedies and privileges pertaining to any of the foregoing,
              whether now existing or hereafter created or arising, and all
              rights with respect to returned and repossessed items of
              inventory;

              Inventory. All of each Borrower's Inventory and Goods now or
              ---------
              hereafter owned by each Borrower, whenever acquired and wherever
              located, and whether held for sale or lease or furnished or to be
              furnished under contracts of service, and all raw materials, work
              in process and materials now or hereafter owned by each Borrower,
              wherever located, and used or consumed in its business, including
              all returned and repossessed items; and all other property now or
              hereafter constituting Inventory;

              Other Collateral. All of each Borrower's Deposit Accounts,
              ----------------
              Documents, Instruments, Investment Property, Letter of Credit
              Rights and Supporting Obligations, whether any of the foregoing
              shall be now owned or hereafter acquired by such Borrower,
              together with all of each Borrower's present and future furniture,
              fixtures, Equipment, machinery, supplies and other assets (other
              than stock, as below provided) and personal property of every type
              or nature whatsoever, including without limitation, all of each
              Borrower's present and future inventions, designs, patents, patent
              applications, trademarks, trademark applications, trade names,
              trade secrets, goodwill, registrations, copyrights, licenses,
              franchises, customer lists, tax refunds, tax refund claims, rights
              of claims against carriers and shippers, leases and rights to
              indemnification;

              Stock. All of each Borrower's right, title and interest in and to
              -----
              the issued and outstanding capital stock standing in such
              Borrower's name on the books of (i) GSE, (ii) Praxa, (iii) ManTech
              Australia International, Inc., a Virginia corporation, and (iv)
              ManTech Europe, Ltd., a private company

                                       26

<PAGE>
              registered in England under No. 2497488 formerly known as Spurland
              Limited ("ManTech Europe"), in each case, whether common and/or
              preferred, and whether now or hereafter issued or outstanding and
              whether now or hereafter acquired by the Borrowers, together with
              all voting or other rights appurtenant thereto, including, without
              limitation, the right to receive all dividends and/or
              distributions, and all proceeds thereof, pursuant to the terms and
              conditions of the Stock Security Agreements;

              Leases. All of each Borrower's present and future right, title and
              ------
              interest in and to any and all leases, occupancy agreements,
              subleases, contracts, licenses, agreements and other
              understandings of or relating to the use, enjoyment and occupancy
              of real property or any improvements thereon.

              Records. All of each Borrower's records, documents and files, in
              -------
              whatever form, pertaining to the Collateral; and

              Proceeds, Etc. Any and all Proceeds, whether cash or non-cash
              -------------
              proceeds, and all increases, substitutions, replacements and/or
              additions to any or all of the foregoing.

              Notwithstanding the foregoing, the above described conveyance
shall not be deemed to include the conveyance of (A) any Government Contract or
other contractual agreement, which by its terms or applicable law may not be
conveyed; it being understood, however, that in any such situation(s), the
Administrative Agent's security interest shall include (i) the entirety of each
Borrower's right, title and interest in and to all accounts receivable and all
other Proceeds directly or indirectly arising from such Government Contract or
other contractual agreement, and (ii) all other rights and interests which any
Borrower may lawfully convey to the Administrative Agent; (B) any stock of a
foreign corporation (other than ManTech Europe) in excess of sixty-six percent
(66%) of all of the issued and outstanding stock of such foreign corporation, or
any other stock or equity interests owned by any Borrower (other than the stock
specifically referenced in this Section above and other stock from time to time
pledged as collateral for the Loan); (C) motor vehicles titled in the name of
any Borrower; and (D) interests in real property owned by any Borrower.

              3.2. No Preference or Priority. It is expressly understood and
                   -------------------------
agreed that each of the Notes shall be secured without preference or priority;
it being the intention of the parties that the Notes shall be co-equal and
coordinate in right of payment of principal, interest, late charges and other
sums due thereunder.

                                   ARTICLE 4
                     CONDITIONS TO THE LENDERS' OBLIGATIONS

              The initial performance of the Lenders' obligations under this
Agreement shall be subject to the following conditions:

              4.1. Compliance with Law and Agreements; Third Party Consents. The
                    -------------------------------------------------------
Lenders shall be reasonably satisfied that (a) the Loan shall be in full
compliance with all legal

                                       27

<PAGE>

requirements, (b) all regulatory and third party consents and approvals required
to be obtained have been obtained, and (c) the Borrowers shall have performed
all agreements theretofore to be performed by the Borrowers.

         4.2. Financial Condition. There shall have been no material adverse
              -------------------
change in the financial condition of the Borrowers, in the aggregate, between
the date of the most recent financial statement(s) delivered to the Lenders and
the date hereof.

         4.3. Opinion of Counsel. The Administrative Agent shall have received
              ------------------
an opinion of Borrowers' counsel with respect to each of the Borrowers (other
than the Borrowers listed on Schedule 4.3 hereto), in form and substance
                             ------------
satisfactory to the Administrative Agent and its counsel.

         4.4. No Default. There shall exist no Event of Default, and no act,
              ----------
event or condition shall have occurred which with notice or the lapse of time,
or both, would constitute an Event of Default.

         4.5. Documentation. The Administrative Agent shall have received an
              -------------
initial Borrowing Base/Non-Default Certificate, the "basket calculation"
statement, in the form required pursuant to Section 6.3(b) of this Agreement,
and such certificates of good standing, corporate resolutions, government
contract assignments, UCC financing statements, opinions, certifications,
schedules to be attached to this Agreement and such other documents, instruments
and agreements as may be reasonably required by the Lenders or the
Administrative Agent, in such form and content and from such parties, as the
Lenders shall require. All documentation relating to the Loan and all related
transactions must be satisfactory in all respects to the Lenders, and their
counsel.

         4.6. Closing Costs and Expenses. The Borrowers shall have paid all fees
              --------------------------
payable to the Administrative Agent and/or the Lenders, plus all closing costs
and expenses incurred by the Administrative Agent in connection with the
transactions contemplated hereby, including, without limitation, all recording
costs.

                                   ARTICLE 5
                         REPRESENTATIONS AND WARRANTIES

         To induce the Lenders to enter into this Agreement, each Borrower
jointly and severally represents, warrants, covenants and agrees as follows:

         5.1. Corporate Existence and Qualification. Each Borrower is a
              -------------------------------------
corporation duly organized, validly existing and in good standing under the laws
of its state of incorporation referenced in the preamble of this Agreement, with
all corporate power and authority and all necessary licenses and permits to own,
operate and lease its properties and carry on its business as now being
conducted, and as it may in the future be conducted. Each Borrower has only one
(1) jurisdiction of incorporation. Each Borrower is duly qualified and
authorized to do business and is in good standing in each jurisdiction in which
the nature of its activities or the character of its properties makes
qualification necessary.

                                       28

<PAGE>

         5.2. Corporate Authority; Noncontravention. The execution, delivery and
              -------------------------------------
performance of the obligations of each Borrower set forth in this Agreement, the
Notes and the other Loan Documents (i) have been duly authorized by all
necessary corporate and/or stockholder action; (ii) do not require the consent
of any governmental body, agency or authority; (iii) will not violate or result
in (and with notice or the lapse of time will not violate or result in) the
breach of any provision of any Borrower's Articles/Certificate of Incorporation
or By-laws, any material indenture, instrument, agreement or other undertaking
to which any Borrower is a party or by which any Borrower is bound, or any order
or regulation of any governmental authority or arbitration board or tribunal;
and (iv) except as permitted by the terms and provisions of this Agreement, will
not result in the creation of a lien, charge or encumbrance of any nature upon
any of the properties or assets of any Borrower. When the Loan Documents are
executed and delivered, they will constitute legal, valid and binding
obligations of each Borrower, enforceable against each Borrower in accordance
with their respective terms, subject to applicable bankruptcy, insolvency and
other similar laws affecting the rights of creditors generally.

         5.3. Financial Position. The financial statements listed on Exhibit 7
              ------------------                                     ---------
hereto, copies of which have been delivered to the Lenders, present fairly the
financial condition of the Borrowers as of the date thereof and the results of
the Borrowers' operations for the periods indicated therein, were prepared in
accordance with GAAP, are true and accurate in all material respects, and are
not misleading in any material respect. All material liabilities, fixed or
contingent, are fully shown or provided for on the referenced financial
statements or the notes thereto as of the dates thereof. There has been no
material adverse change in the business, property or condition (financial or
otherwise) of the Borrowers since the date of the most recent financial
statements listed on Exhibit 7.
                     ---------

         5.4. Payment of Taxes. Each Borrower has filed all tax returns and
              ----------------
reports required to be filed by it with the United States Government and/or with
all state and local governments, and has paid in full or made adequate provision
on its books for the payment of all taxes, interest, penalties, assessments or
deficiencies shown to be due or claimed to be due on or in respect of such tax
returns and reports, except to the extent that the validity or amount thereof is
being contested in good faith by appropriate proceedings and the non-payment
thereof pending such contest will not result in the execution of any tax lien or
otherwise jeopardize the Administrative Agent's or the Lenders' interests in any
part of the Collateral.

         5.5. Accuracy of Submitted Information; Omissions. As of the date
              --------------------------------------------
furnished, all documents, certificates, information, materials and financial
statements furnished or to be furnished to any Lender or the Administrative
Agent pursuant to this Agreement or otherwise in connection with the Loan (i)
are true and correct in all material respects; (ii) do not contain any untrue
statement of a material fact; and (iii) do not omit any material fact necessary
to make the statements contained therein or herein not misleading. No Borrower
is aware of any fact which has not been disclosed to the Administrative Agent in
writing which materially adversely affects, or so far as any Borrower can now
reasonably foresee, could reasonably be expected to materially adversely affect,
the properties, business, profit or condition (financial or otherwise) of any
Borrower or the ability of any Borrower to perform its obligations set forth in
this Agreement or in any other Loan Document.

                                       29

<PAGE>

         5.6.  Government Contracts. No notice of suspension, debarment, cure
               --------------------
notice, show cause notice or notice of termination for default has been issued
by the Government to any Borrower, and no Borrower is a party to any pending, or
to any Borrower's knowledge threatened, suspension, debarment, termination for
default issued by the Government or other adverse Government action or
proceeding in connection with any Government Contract; it being understood and
agreed that, for purposes hereof, normal and customary reviews and audits
conducted by the Government in the ordinary course of business shall not be
deemed adverse Government action(s) or proceeding(s). All Government Contracts
which constitute Material Contracts and have a remaining term of six (6) months
or longer are listed on Schedule 5.6 hereto.
                        ------------

         5.7.  No Defaults or Liabilities. No Borrower is in default in any
               --------------------------
material respect in the performance of any obligation, covenant or condition
contained in any material agreement to which it is a party. Additionally, except
for the matters disclosed on Schedule 5.9 hereto, there is no litigation, legal
                             ------------
or administrative proceeding or investigation pending against any Borrower, and
no litigation, legal or administrative proceeding or investigation has been
threatened in writing against any Borrower, which has not been disclosed to the
Administrative Agent and/or the Lenders in writing and which involves amounts in
excess of the Dollar Equivalent Amount of Five Hundred Thousand and No/100
Dollars ($500,000.00) or which could reasonably be expected to prejudice the
Administrative Agent's or any Lender's rights under any Loan Document in any
material respect.

         5.8.  No Violations of Law. No Borrower is in violation of any
               --------------------
Applicable Laws in any material respect; no Borrower has failed to obtain any
license, permit, franchise or other governmental authorization necessary to the
ownership of its properties or to the conduct of its business, and each Borrower
has conducted its business and operations in compliance with all Applicable Laws
in all material respects.

         5.9.  Litigation and Proceedings. Except for the matters set forth on
               --------------------------
Schedule 5.9 attached hereto, no action, suit or proceeding against or affecting
------------
any Borrower is presently pending, or to the knowledge of any Borrower,
threatened, in any court, before any governmental agency or department, or
before any arbitration board or tribunal, which involves the possibility of any
judgment or liability in excess of the Dollar Equivalent Amount of Five Hundred
Thousand and No/100 Dollars ($500,000.00) and is not fully covered by insurance.
No Borrower is in default with respect to any order, writ, injunction or decree
of any court, governmental authority or arbitration board or tribunal.

         5.10. Security Interest in the Collateral. Each Borrower is the sole
               -----------------------------------
legal and beneficial owner of the Collateral owned or purported to be owned by
it, free and clear of all liens, claims and encumbrances of any nature, except
for the Permitted Liens and other liens expressly permitted by the terms and
provisions of this Agreement.

         5.11. Principal Place of Business; Location of Books and Records. Each
               ----------------------------------------------------------
Borrower maintains its principal place of business and the office where it keeps
its books and records with respect to accounts and contracts rights at the
locations listed on Schedule 2 hereto. Set forth on Schedule 5.11 hereto is a
                    ----------                      -------------
list of each Borrower's business locations as of the Closing Date, and all
places where any of the Collateral is located. The locations set forth on

                                       30

<PAGE>

Schedule 5.11 hereto denoted with an asterisk reflect all locations where
-------------
Borrower assets are valued in excess of the Dollar Equivalent Amount of One
Hundred Thousand and No/100 Dollars ($100,000.00). Each Borrower agrees to
notify the Administrative Agent in writing at least ten (10) days prior to any
change in its principal place of business, or any change in the location of the
office where it keeps its books and records with respect to accounts and
contract rights, or any change of or addition to the locations where any
Collateral is located.

     5.12. Fiscal Year. Each Borrower's fiscal year ends on December 31.
           -----------

     5.13. Pension Plans.
           -------------

           (a) The present value of all benefits vested under all "employee
pension benefit plans", as such term is defined in Section 3(2) of the Employee
Retirement Income Security Act of 1974 ("ERISA"), from time to time maintained
by the Borrowers (individually, a "Pension Plan" and collectively, the "Pension
Plans") did not, as of December 31, 2000, exceed the value of the assets of the
Pension Plans allocable to such vested benefits;

           (b) No Pension Plan, trust created thereunder or other person dealing
with any Pension Plan has engaged in a non-exempt transaction proscribed by
Section 406 of ERISA or a non-exempt "prohibited transaction", as such term is
defined in Section 4975 of the Internal Revenue Code;

           (c) No Pension Plan or trust created thereunder has been terminated
within the last three (3) years, and there have been no "reportable events" (as
such term is defined in Section 4043 of ERISA and the regulations thereunder)
with respect to any pension plan or trust created thereunder after June 30,
1974; and

           (d) No Pension Plan or trust created thereunder has incurred any
"accumulated funding deficiency" (as such term is defined in Section 302 of
ERISA or Section 412 of the Internal Revenue Code) as of the end of any plan
year, whether or not waived, since the effective date of ERISA.

     5.14.  O.S.H.A. and Environmental Compliance.
            -------------------------------------

           (a) Each Borrower has duly complied in all material respects with,
and its facilities, business assets, property, leaseholds and equipment are in
compliance in all material respects with, the provisions of the Federal
Occupational Safety and Health Act ("O.S.H.A."), the Environmental Protection
Act, RCRA and all other environmental laws which non-compliance with could
result in a material adverse effect on the business, condition (financial or
otherwise) or results of operations of any Borrower; and there have been no
citations, notices, notifications or orders of any such non-compliance issued to
any Borrower or relating to its business, assets, property, leaseholds or
equipment under any such laws, rules or regulations;

           (b) each Borrower has been issued all required federal, state and
local licenses, certificates and permits necessary or appropriate in the
operation of its facilities, businesses, assets, property, leaseholds and
equipment, unless the failure to obtain any such

                                       31

<PAGE>

license, certificate or permit would not have a material adverse effect on the
business condition (financial or otherwise) or results of operations of any
Borrower; and

             (c) (i) there are no visible signs of releases, spills, discharges,
leaks or disposal (collectively referred to herein as "Releases") of Hazardous
Substances at, upon, under or within any Real Property owned, or to the actual
knowledge of any Borrower any premises leased, by any Borrower; (ii) there are
no underground storage tanks or polychlorinated biphenyls on any Real Property
owned, or to the actual knowledge of any Borrower any premises leased, by any
Borrower; (iii) no Real Property owned, or to the actual knowledge of any
Borrower premises leased, by any Borrower has ever been used by any Borrower
(and to the best of each Borrower's knowledge, any other person) as a treatment,
storage or disposal facility for Hazardous Waste; and (iv) no Hazardous
Substances are present on any Real Property owned, or to the actual knowledge of
any Borrower any premises leased, by any Borrower, except for such quantities of
Hazardous Substances as are handled in all material respects in accordance with
all applicable manufacturer's instructions and governmental regulations, and as
are necessary or appropriate for the operation of the business of the Borrowers.
Each Borrower, for itself and its successors and assigns, hereby covenants and
agrees to indemnify, defend and hold harmless the Agents and Lenders from and
against any and all liabilities, losses, claims, damages, suits, penalties,
costs and expenses of every kind or nature, including, without limitation,
reasonable attorneys' fees arising from or in connection with (i) the presence
or alleged presence of any Hazardous Substance or Hazardous Waste on, under or
about any property of any Borrower (including, without limitation, any property
or premises now or hereafter owned or leased by any Borrower), or which is
caused by or results from, directly or indirectly, any act or omission to act by
any Borrower; and (ii) any Borrower's violation of any environmental statute,
ordinance, order, rule or regulation of any governmental entity or agency
thereof (including, without limitation, any liability arising under CERCLA,
RCRA, HMTA or any Applicable Laws).

     5.15. Intellectual Property. All patents, patent applications, trademarks,
           ---------------------
trademark applications, copyrights, copyright applications, tradenames, trade
secrets and licenses necessary for the conduct of the business of each Borrower
are (i) owned or utilized by such Borrower, (ii) valid and, except with respect
to licenses, have been duly registered or filed with all appropriate
governmental authorities, and (iii) listed on Schedule 5.15 (a) hereto. Except
                                              -----------------
as disclosed in Schedule 5.15(a) hereto, there is no objection or pending
                ----------------
challenge to the validity of any such patent, trademark, copyright, tradename,
trade secret or license; no Borrower is aware of any grounds for any such
challenge or objection thereto; except as disclosed in Schedule 5.15(b) hereto,
                                                       ----------------
no Borrower pays any royalty to anyone in connection with any patent, trademark,
copyright, tradename, trade secret or license; and each Borrower has the right
to bring legal action for the infringement of any such patent, trademark,
copyright, tradename, trade secret or license.

     5.16. Existing or Pending Defaults; Material Contracts. All Material
           ------------------------------------------------
Contracts are listed on Schedule 5.16(a) hereto. Except as set forth on Schedule
                        ----------------                                --------
5.16(b) attached hereto, no Borrower is aware of any pending or threatened
-------
litigation, or any other legal or administrative proceeding or investigation
pending or threatened, against any Borrower arising from or related to any
Material Contract which could reasonably be expected to have a material adverse
effect on the Administrative Agent's or any Lender's rights in connection with
such Material Contract.

                                       32

<PAGE>

     5.17. Leases and Real Property. No Borrower owns any real property. All
           ------------------------
material leases and other agreements under which any Borrower occupies real
property are in full force and effect and constitute legal, valid and binding
obligations of, and are legally enforceable against, the Borrower party thereto
and, to the Borrowers' best knowledge, are the binding obligations of and
legally enforceable against, the other parties thereto. All necessary
governmental approvals, if any, have been obtained for each such material lease
or agreement, and there have been no threatened cancellations thereof or
outstanding material disputes with respect thereto. The landlord for the
premises in which the Parent Company's headquarters is located has subordinated
(or expressly assumed terms, covenants and conditions of subordination) for the
benefit of the Administrative Agent, on terms and conditions reasonably
satisfactory to the Administrative Agent, any landlord's or lessor's lien which
may now or hereafter exist (whether by statute, contract or otherwise) on any of
the Collateral located at such premises.

     5.18. Labor Relations. There are no strikes, work stoppages, material
           ---------------
grievance proceedings, union organization efforts or other controversies
pending, or to any Borrower's knowledge, threatened or reasonably anticipated,
between any Borrower and (i) any current or former employee of any Borrower or
(ii) any union or other collective bargaining unit representing any such
employee. Each Borrower has complied and is in compliance in all material
respects with all Applicable Laws relating to employment or the workplace,
including, without limitation, provisions relating to wages, hours, collective
bargaining, safety and health, work authorization, equal employment opportunity,
immigration, withholding, unemployment compensation, employee privacy and right
to know. Except as set forth on Schedule 5.18 hereto, there are no collective
                                -------------
bargaining agreements, employment agreements between any Borrower and any of its
employees, or professional service agreements not terminable at will relating to
the businesses or assets of any Borrower. The consummation of the transactions
contemplated hereby will not cause any Borrower to incur or suffer any liability
relating to, or obligation to pay, severance, termination or other similar
payments to any person or entity.

     5.19. Assignment of Government Contracts. No existing Government Contract
           ----------------------------------
of any Borrower (and no present or future interest of any Borrower, in whole or
in part, in, to or under any such Government Contract) is currently assigned,
pledged, hypothecated or otherwise transferred to any person or entity (other
than in favor of the Administrative Agent for the benefit of the Lenders
ratably).

     5.20. Contribution Agreement. The Contribution Agreement is in full force
           ----------------------
and effect, has not been modified, altered or amended in any respect whatsoever
(other than to add a new Borrower party thereto from time to time), and no
Borrower is in default thereunder.

     5.21. Intentionally Deleted.
           ---------------------

     5.22. Ownership of the Borrowers. As of the date of this Agreement (i) all
           --------------------------
of the issued and outstanding capital stock of the Parent Company is owned in
the percentages and by the persons referenced on Schedule 5.22(a) hereto; and
                                                 ----------------
(ii) all of the issued and outstanding capital stock of each other Borrower is
owned by either the Parent Company or another Borrower, except as described on
Schedule 5.22(b) hereto.
----------------

                                       33

<PAGE>
     5.23. Solvency. Both prior to and after giving effect to the transactions
           --------
contemplated by the terms and provisions of this Agreement, (i) each Borrower
(other than those Borrowers listed on Schedule 5.23 hereto) owned and owns
                                      -------------
property (including, without limitation, the Borrower's rights under the
Contribution Agreement) whose fair saleable value is greater than the amount
required to pay all of such Borrower's Indebtedness (including contingent
debts), (ii) each Borrower was and is able to pay all of its Indebtedness as
such Indebtedness matures, and (iii) each Borrower had and has capital
sufficient to carry on its business and transactions and all business and
transactions in which it is about to engage. For purpose hereof, "Indebtedness"
means, without duplication (a) all items which in accordance with GAAP would be
included in determining total liabilities as shown on the liability side of a
balance sheet of such Borrower as of the date on which Indebtedness is to be
determined, (b) all obligations of any other person or entity which such
Borrower has guaranteed, (c) reimbursement obligations in connection with
letters of credit issued for the benefit of such Borrower, and (d) the
Obligations.

     5.24. Survival of Representations and Warranties. All representations and
           ------------------------------------------
warranties made herein shall survive the making of the Loan, and shall be deemed
remade and redated as of the date of each request for an advance or readvance of
any Loan proceeds, unless the Borrower is unable to remake and/or redate any
such representation or warranty, discloses the same to the Lenders in writing,
and such inability does not constitute or give rise to an Event of Default.

                                    ARTICLE 6
                     AFFIRMATIVE COVENANTS OF THE BORROWERS

     So long as any Obligation remains outstanding or this Agreement remains in
effect, each Borrower jointly and severally covenants and agrees with the
Lenders that:

     6.1. Payment of Loan Obligations. Each Borrower will duly and punctually
          ---------------------------
pay all sums to be paid to the Lenders and the Agents in accordance with the
terms and conditions of the Loan Documents, and will comply with, perform and
observe all of the terms thereof.

     6.2. Payment of Taxes. Each Borrower will promptly pay and discharge when
          ----------------
due all federal, state and other governmental taxes, assessments, fees and
charges imposed upon it, or upon any of its properties or assets, except to the
extent that the non-payment thereof will not result in the execution of any tax
lien or otherwise jeopardize the Administrative Agent's or the Lenders' interest
in any part of the Collateral.

     6.3. Delivery of Financial and Other Statements. The Borrowers shall
          ------------------------------------------
deliver to the Administrative Agent and the Lenders financial and other
statements, each of which shall, unless otherwise expressly provided to the
contrary, be prepared in accordance with GAAP consistently applied, as follows:

          (a) on or before the one hundred twentieth (120th) day following the
close of each fiscal year, the Borrowers will submit to the Administrative Agent
and the Lenders (i) annual audited and unqualified consolidated financial
statements, which shall be accompanied by consolidating schedules and management
letters (if issued) and certified by a nationally

                                       34

<PAGE>

recognized independent certified public accountant, and (ii) an annual budget
for the then current year, in form reasonably satisfactory to the Administrative
Agent, certified by the Borrowers' Chief Financial Officer or another duly
authorized executive officer of the Borrowers;

          (b) on or before the forty-fifth (45th) day following the close of
each calendar quarter, the Borrowers will submit to the Administrative Agent and
the Lenders (i) a consolidated and consolidating balance sheet, income statement
and statement of stockholders' equity, reporting the Borrowers' current
financial position and the results of their operations for the quarter then
ended and year-to-date, (ii) internally prepared statements of cash flow and
contract/status backlog reports, (iii) a Quarterly Covenant
Compliance/Non-Default Certificate in the form of Exhibit 5 hereto, and (iv) a
                                                  ---------
statement detailing (A) the Borrowers' availability under the "basket
limitations" set forth in Section 7.8 of this Agreement, and (B) the Dollar
Equivalent Amount of outstanding and unpaid Loan proceeds to ARL and Vobix, each
of which shall be in form reasonably satisfactory to the Administrative Agent
and certified by the Borrowers' Chief Financial Officer or another duly
authorized executive officer of the Borrowers;

          (c) on or before the twenty-fifth (25th) day following the close of
each calendar month, the Borrowers will submit to the Administrative Agent and
the Lenders a Borrowing Base/Non-Default Certificate in the form of Exhibit 4
                                                                    ---------
hereto, accompanied by detailed current aged billed and unbilled accounts
receivable reports, each of which shall be certified by an authorized executive
officer of the Borrowers;

          (d) within five (5) days of issuance, distribution or filing, as
applicable, the Borrowers will submit to the Administrative Agent and the
Lenders copies of all public filings, disclosure statements and/or registration
statements which any Borrower issues to, distributes to or files with the
Securities and Exchange Commission or any state agency or department regulating
securities (or any other person or entity, pursuant to the rules and/or
regulations of the Securities and Exchange Commission or any state agency or
department regulating securities); and

          (e) promptly upon the request of the Administrative Agent or any
Lender, the Borrowers will provide to the Administrative Agent and the Lenders
such other information and/or reports relating to each Borrower's business,
operations, properties or prospects as the Administrative Agent or Lenders may
from time to time reasonably request.

     6.4. Maintenance of Records; Review by the Lenders. Each Borrower will
          ---------------------------------------------
maintain at all times proper books of record and account in accordance with
GAAP, consistently applied, and, subject to any confidentiality and secrecy
requirements imposed by any Government agency, will permit the Lenders' officers
or any of the Lenders' authorized representatives or accountants to visit and
inspect each Borrower's offices and properties, examine its books of account and
other records, and discuss its affairs, finances and accounts with the officers
of the Parent Company, all at such reasonable times during normal business
hours, and as often as the Lenders may desire.

     6.5. Maintenance of Insurance Coverage. Each Borrower will maintain in
          ---------------------------------
effect fire and extended coverage insurance, public liability insurance,
worker's compensation insurance and insurance on the Collateral and each of its
properties, with responsible insurance

                                       35

<PAGE>

companies, in such amounts and against such risks as are customary for similar
businesses, required by governmental authorities, if any, having jurisdiction
over all or part of its operations, or otherwise reasonably required by the
Administrative Agent, and will furnish to the Administrative Agent certificates
evidencing such continuing insurance. The Administrative Agent, for the benefit
of the Lenders, shall be named as loss payee on all hazard and casualty
insurance policies by means of a standard noncontributory mortgagee clause and
as an additional insured on all liability insurance policies. All insurance
policies shall also provide for (i) not less than thirty (30) days written
notice to the Administrative Agent prior to expiration, cancellation or material
change; and (ii) waiver of subrogation. The Lenders acknowledge that the
insurance maintained by the Borrowers as of the date of this Agreement, as
evidenced by the certificates of insurance delivered to the Lenders for the
period from March 3, 2001 (May 1, 2001 with respect to property coverage)
through March 3, 2002 (May 1, 2002 with respect to property coverage), satisfies
the requirements of this Section 6.5 as of the date of this Agreement.

     6.6. Maintenance of Property/Collateral; Performance of Contracts. Each
          ------------------------------------------------------------
Borrower will at all times maintain the Collateral and its tangible property,
both real and personal, in good order and repair (subject to ordinary wear and
tear), and will permit the Administrative Agent's officers or authorized
representatives to visit and inspect the Collateral and each Borrower's tangible
property at such reasonable times during normal business hours, as and when the
Administrative Agent deems necessary or appropriate; provided, however, that the
Administrative Agent's review of any and all "classified contracts" shall be
subject to compliance with Applicable Laws. Each Borrower shall perform all
obligations under all material contracts to which it is a party (including,
without limitation, all obligations as contractor under any Material Contract),
including all exhibits and other attachments to such contracts, all
modifications thereto and all documents and instruments delivered pursuant
thereto, and will comply in all material respects with all laws, rules and
regulations governing the execution, delivery and performance thereof.

     6.7. Maintenance of Corporate Existence. Each Borrower will maintain its
          ----------------------------------
corporate existence and will provide the Administrative Agent with evidence of
the same from time to time upon the Administrative Agent's request.

     6.8. Maintenance of Certain Accounts with the Administrative Agent. Each
          -------------------------------------------------------------
Borrower will maintain its primary operating accounts, including all primary
depository accounts (time and demand), disbursement accounts and collection
accounts with the Administrative Agent.

     6.9. Maintenance of Management. The Borrowers will notify the
          -------------------------
Administrative Agent and the Lenders in writing of the change of any corporate
officer or director of the Parent Company, within ten (10) days of the date of
any such change.

     6.10. Disclosure of Defaults, Etc.
           ---------------------------

           (a) Promptly upon the occurrence thereof, each Borrower will provide
the Administrative Agent and the Lenders with written notice of any Event of
Default, or any act, event or occurrence that upon the giving of any required
notice or the lapse of time, or both, would constitute an Event of Default. In
addition, each Borrower will promptly advise the

                                       36

<PAGE>

Administrative Agent and the Lenders in writing of any condition, act, event or
occurrence which comes to such Borrower's attention that would or could
reasonably be expected to prejudice the Administrative Agent's or any Lender's
rights in connection with any Material Contract, the Collateral, this Agreement,
any Note or any other Loan Document, including, without limitation, the details
of any pending or threatened suspension, debarment or other governmental action
or proceeding, any material pending or threatened litigation, and any other
legal or administrative proceeding or investigation pending or threatened
against any Borrower, including the entry of any judgment in excess of the
Dollar Equivalent Amount of Five Hundred Thousand and No/100 Dollars
($500,000.00) or lien (other than a Permitted Lien) against any Borrower, its
assets or property.

           (b) If, at any time after the Closing Date, any Borrower shall
receive any letter, notice, subpoena, court order, pleading or other document
issued, given or delivered by the Government or by any person or entity acting
for or on behalf of the Government with respect to, or in any manner related to,
Items 1 or 3 set forth in Schedule 5.9 hereto, such Borrower shall deliver a
                          ------------
true, correct and complete copy of such letter, notice, subpoena, court order,
pleading or document to the Administrative Agent, the Administrative Agent's
counsel and each Lender within one (1) Business Day of such Borrower's receipt
thereof. Furthermore, if any Borrower shall issue, give or deliver to the
Government or any person or entity acting for or on behalf of the Government any
letter, notice, subpoena, court order, pleading or other document with respect
to, or in any manner related to, Items 1 or 3 set forth in Schedule 5.9 hereto,
                                                           ------------
such Borrower shall deliver a true, correct and complete copy of such letter,
notice, subpoena, court order, pleading or other document to the Administrative
Agent, the Administrative Agent's counsel and each Lender concurrent with the
Borrower's issuance or delivery thereof to the Government. If any letter,
notice, subpoena, court order, pleading or other document required to be
delivered to the Administrative Agent, the Administrative Agent's counsel and
each Lender pursuant to this Section 6.10 contains any information deemed
"classified" by the Government and/or the dissemination of any such information
to the Administrative Agent, the Administrative Agent's counsel and each Lender
would result in the Borrowers violating any Applicable Law, then the Borrowers
shall deliver to the Administrative Agent, the Administrative Agent's counsel
and each Lender a summary of such letter, notice, subpoena, court order,
pleading or other document containing a summary thereof, but including as much
(but no more than) detail as can be included therein without violating any
Applicable Law.

     6.11. Security Perfection; Assignment of Claims Act; Payment of Costs. The
           ---------------------------------------------------------------
Borrowers will execute and deliver and pay the costs of recording and filing
financing statements, continuation statements, termination statements,
assignments and other documents, as the Administrative Agent may from time to
time deem necessary or appropriate for the perfection of any liens granted to
the Administrative Agent or Lenders pursuant hereto or pursuant to any other
Loan Document. On or before the date which is ninety (90) days from the date of
any Government Contract hereafter entered into by one or more Borrowers, such
Borrower(s) shall execute all documents necessary or appropriate in order to
comply with the Assignment of Claims Act of 1940, as amended, 31 U.S.C. Section
3727 and 41 U.S.C. Section 15 (the "Government Contract Assignments") in
connection with each such Government Contract; it being understood and agreed,
however, that no Government Contract Assignment is being required for any
Government Contract (a) which has a remaining value of less than Five Million
and No/100 Dollars ($5,000,000.00), (b) which has a term of less than six (6)
months, or

                                       37

<PAGE>

(c) pursuant to which a Borrower is not a/the prime contractor thereof. All
Government Contract Assignments shall be held in escrow pursuant to the Escrow
Agreement attached as Exhibit 8 hereto, as the same may be amended from time to
time. All costs and expenses incurred in connection with the escrow of the
Government Contract Assignments shall be borne solely by the Borrowers.
Additionally, the Borrowers will pay any and all costs incurred in connection
with the transactions contemplated hereby, as well as any and all taxes (other
than the Lenders' income and franchise taxes), which may be payable as a result
of the execution of this Agreement or any agreement supplemental hereto, or as a
result of the execution and/or delivery of any Note or other Loan Document.

        6.12. Defense of Title to Collateral. The Borrowers will at all times
              ------------------------------
defend the Lenders', the Administrative Agent's and Borrowers' rights in the
Collateral, subject to the Permitted Liens, against all persons and all claims
and demands whatsoever, and will, upon request of the Administrative Agent (i)
furnish such further assurances of title as may be required by the
Administrative Agent, and (ii) do any other acts necessary to effectuate the
purposes and provisions of this Agreement, or as required by law or otherwise in
order to perfect, preserve, maintain or continue the interests of the
Administrative Agent and Lenders in the Collateral.

        6.13. Compliance with Law. Each Borrower will conduct its businesses and
              -------------------
operations in compliance in all material respects with (i) all Applicable Laws
and requirements of all federal, state and local regulatory authorities having
jurisdiction, (ii) the provisions of its charter documents and by-laws, (iii)
all agreements and instruments by which it or any of its properties may be
bound, and (iv) all applicable decrees, orders and judgments.

        6.14. Other Collateral Covenants.
              --------------------------

              (a) The Borrowers will, at their own expense, make, execute,
endorse, acknowledge, file and/or deliver to the Administrative Agent from time
to time such lists, descriptions and designations of Collateral, warehouse
receipts, receipts in the nature of warehouse receipts, bills of lading,
documents of title, vouchers, invoices, schedules, confirmatory assignments,
conveyances, financing statements, transfer endorsements, powers of attorney,
certificates, reports and other assurances or instruments, and take such further
steps relating to the Collateral and other property or rights covered by the
interests hereby granted which the Administrative Agent deems reasonably
appropriate or advisable to perfect, preserve or protect its ownership and
security interests in the Collateral.

              (b) Unless waived in writing by the Administrative Agent, the
Borrowers shall obtain authenticated control letters from each issuer of
uncertificated securities, securities intermediary or commodities intermediary
issuing or holding any financial assets or commodities to or for any of the
Borrowers.

              (c) Following the occurrence of an Event of Default, if any
Borrower is or becomes the beneficiary of a letter of credit, such Borrower
shall promptly, and in any event within two (2) Business Days after becoming a
beneficiary, notify the Administrative Agent thereof and, following the
Administrative Agent's request, enter into a tri-party agreement with the
Administrative Agent and the issuer and/or confirmation bank with respect to all
Letter of Credit Rights in connection with such letter of credit, assigning such
Letter of Credit Rights to

                                       38

<PAGE>

the Administrative Agent and directing all payments thereunder to an account
designated by the Administrative Agent, which tri-party agreement shall be in
form and substance reasonably satisfactory to the Administrative Agent.

         (d) The Borrowers shall take all steps necessary to grant the
Administrative Agent control of all electronic chattel paper in accordance with
the UCC and all "transferable records" as defined in each of the Uniform
Electronic Transactions Act and the Electronic Signatures in Global and National
Commerce Act.

         (e) The Borrowers hereby irrevocably authorize the Administrative Agent
at any time and from time to time to file in any filing office in any Uniform
Commercial Code jurisdiction any initial financing statements and amendments
thereto that (A) describe Collateral (I) as all assets of the Borrowers or words
of similar effect (other than assets expressly excluded from the description of
Collateral herein), regardless of whether any particular asset comprised in the
Collateral falls within the scope of Article 9 of the Uniform Commercial Code in
such jurisdiction, or (II) as being of an equal or lesser scope or with greater
detail, and (B) contain any other information required by part 5 of Article 9 of
the Uniform Commercial Code for the sufficiency or filing office acceptance of
any financing statement or amendment, including (I) whether any Borrower is an
organization, the type of organization and any organization identification
number issued to such Borrower, and (II) in the case of a financing statement
filed as a fixture filing or indicating Collateral as as-extracted collateral or
timber to be cut, a sufficient description of real property to which the
Collateral relates. The Borrowers agree to furnish any such information to the
Administrative Agent promptly upon request. The Borrowers also ratify their
authorization for the Administrative Agent to have filed in any Uniform
Commercial Code jurisdiction any initial financing statements or amendments
thereto if filed prior to the date hereof.

         (f) The Borrowers shall promptly, and in any event within two (2)
Business Days after the same is acquired by any Borrower, notify the
Administrative Agent of any Commercial Tort Claim (as defined in the UCC)
acquired by a Borrower and unless otherwise consented to by the Administrative
Agent, such Borrower shall enter into a supplement to this Agreement, granting
to the Administrative Agent a security interest in such Commercial Tort Claim.

         (g) If any Borrower retains possession of any Chattel Paper or
Instruments with the Administrative Agent's consent, such Chattel Paper and
Instruments shall be marked with the following legend: "This writing and the
obligations evidenced or secured hereby are subject to the security interest of
Citizens Bank, as Administrative Agent."

         (h) Without limiting the prohibitions on mergers involving the
Borrowers contained in this Agreement, no Borrower shall reincorporate or
reorganize itself under the laws of any jurisdiction other than the jurisdiction
in which it is incorporated as of the date hereof without the prior written
consent of the Administrative Agent.

         (i) Each Borrower acknowledges that it is not authorized to file any
financing statement or amendment or termination statement with respect to any
financing statement without the prior written consent of the Administrative
Agent and agrees that it will not do so

                                       39

<PAGE>

without the prior written consent of the Administrative Agent, subject to such
Borrower's rights under Section 9-509(d)(2) of the UCC.

         6.15. Financial Covenants of the Borrowers. So long as any Obligation
               ------------------------------------
remains outstanding or this Agreement remains in effect, the Borrowers will
comply with each of the financial covenants set forth below.

               (a) Net Worth. The Borrowers will at all times maintain on a
                   ---------
consolidated basis Net Worth of not less than the sum of ninety-five percent
(95%) of the Borrowers' Net Worth, determined as of September 30, 2001, plus
seventy-five percent (75%) of net income arising after September 30, 2001 (not
to be reduced for consolidated losses), plus ninety percent (90%) of equity
issuances. For purposes of this Agreement, "Net Worth" shall mean shareholders'
equity (other than minority shareholder interests), as determined in accordance
with GAAP.

               (b) Fixed Charge Coverage Ratio. The Borrowers will maintain on a
                   ---------------------------
consolidated basis for each quarter, a Fixed Charge Coverage Ratio of not less
than 1.25 to 1.00. For purposes of the foregoing, "Fixed Charge Coverage Ratio"
shall mean the Borrowers ` EBITDA, plus real property rent expense, minus cash
                                   ----                             -----
taxes paid, minus capital expenditures (excluding capitalized software), divided
            -----                                                        -------
by the Borrower's real property rent expense, plus interest expense, plus
--                                            ----                   ----
required principal payments on debt and capital leases. The Fixed Charge
Coverage Ratio shall be measured on the last day of each fiscal quarter
throughout the term of the Loan.

               (c) Total Debt to EBITDA Ratio. The Borrowers will maintain on a
                   --------------------------
consolidated basis for each quarter ending during the periods specified below, a
Total Debt to EBITDA ratio of not more than the following:

                                                         Required Total Debt
                                                         ------------------
                              Period                      to EBITDA Ratio
                              ------                      ---------------

                   From the date of this Agreement
                   through December 31, 2001                 3.25 to 1.0

                   From January 1, 2002 through
                   December 31, 2002                         3.00 to 1.0

                   From January 1, 2003 through the
                   Maturity Date                             2.75 to 1.0

     For purposes of the foregoing, "Total Debt" shall have the meaning
     attributed to such term in the "Certain Definitions" section of this
     Agreement. The Total Debt to EBITDA ratio shall be measured on the last day
     of each fiscal quarter throughout the term of the Loan.

               (d) EBITDA to Interest Expense Ratio. The Borrowers will maintain
                   --------------------------------
on a consolidated basis for each quarter, an EBITDA to Interest Expense ratio of
not less than 2.50 to

                                       40

<PAGE>

1.00. The Ratio of EBITDA to Interest Expense shall be measured on the last day
of each fiscal quarter throughout the term of the Loan.

           (e) Capital Expenditures. The Borrowers shall not, on a consolidated
               --------------------
basis, make or incur any capital expenditures in excess of the Dollar Equivalent
Amount of Seven Million Five Hundred Thousand and No/100 Dollars
($7,500,000.00), in the aggregate, during any twelve (12) month period. For
purposes hereof, capital expenditures shall include, but not be limited to,
leasehold improvements and capitalized software, but shall exclude payments due
in connection with the Enterprise Resource Planning Operating Lease.

     The financial covenants referenced above shall be calculated and tested on
the basis of twelve (12) month trailing results, and shall include the twelve
(12) month trailing results of any entity acquired with the consent of the
Administrative Agent and consolidated into the Borrowers' financial statements
within the twelve (12) month period immediately preceding the applicable
covenant calculation date; provided that the financial covenant calculations
referenced above shall not include nor take into account any of the operating
results of Praxa. Unless otherwise defined, all financial terms used in this
Section 6.15 shall have the meanings attributed to such terms in accordance with
GAAP.

     6.16. Intentionally Omitted.
           ---------------------

     6.17. Landlord Waivers; Subordination. The Borrowers shall provide landlord
           -------------------------------
waivers to the Administrative Agent with respect to any location at which any
Borrower now or hereafter stores, keeps or locates its books and records. The
Borrowers shall exercise reasonable efforts to provide landlord waivers to the
Administrative Agent prior to any Borrower storing, keeping or locating any
other assets and/or inventory of such Borrower on the lessor's/landlord's
premises with respect to any location at which any Borrower hereafter stores,
keeps or locates such other assets and/or inventory having a value in excess of
the Dollar Equivalent Amount of Five Hundred Thousand and No/100 Dollars
($500,000.00), in the aggregate. These landlord waivers shall subordinate any
statutory, contractual or other lien the lessor/landlord may have in any of the
Collateral to the lien, operation and effect of the lien being granted to the
Administrative Agent pursuant to this Agreement, and shall be in form and
substance reasonably acceptable to the Administrative Agent.

     6.18. Substitute Notes. Upon request of the Administrative Agent, each
           ----------------
Borrower shall execute and deliver to the Administrative Agent substitute
promissory notes, in form and substance satisfactory to the Administrative Agent
in all respects, payable to the order of such person or entity as may be
designated by the Administrative Agent; it being understood and agreed, however,
that the aggregate principal amount of all outstanding promissory notes shall
not exceed the Commitment Amount (plus the Swing Line Commitment Amount) as of
the date such substitute note(s) are issued.

     6.19. Interest Rate Contracts. The Borrowers may have in effect, from time
           -----------------------
to time, interest rate protection agreements ("Interest Rate Contracts")
reasonably satisfactory to the Administrative Agent. Any such Interest Rate
Contract must be purchased from a Lender, an affiliate of a Lender or any
financial institution reasonably acceptable to the Administrative Agent. The
Borrowers' obligations under any Interest Rate Contract purchased from a Lender
or

                                       41

<PAGE>

an affiliate of a Lender shall be secured by the Collateral on a pari passu
basis. All other Interest Rate Contracts shall be unsecured in all respects. The
Borrowers shall determine to their own satisfaction whether each such Interest
Rate Contract is sufficient to meet the Borrowers' needs for interest rate
protection, and neither the Agents nor any Lender shall have any obligation or
liability with respect thereto, nor any obligation to propose, quote or enter
into any Interest Rate Contract, unless such Interest Rate Contract shall be on
terms and conditions satisfactory to the applicable Lender in all respects.

                                   ARTICLE 7
                       NEGATIVE COVENANTS OF THE BORROWERS

         So long as any Obligation remains outstanding or this Agreement remains
in effect, each Borrower jointly and severally covenants and agrees that,
without the prior written consent of the Administrative Agent, the Borrowers
will not:

         7.1. Change of Control; Disposition of Assets; Merger.
              ------------------------------------------------

              (a) Permit majority or effective control of any Borrower to be
sold, assigned or otherwise transferred, legally or equitably, to any person or
entity, except to another Borrower or a Pedersen Entity; provided that such
entity, upon its acquisition of majority or effective control of any such
Borrower, becomes a "Borrower" hereunder (if not already a Borrower in which the
Administrative Agent has a perfected security interest in and to all of its
assets constituting Collateral) and pledges all of its assets (of the kind and
nature pledged by each Borrower pursuant to the terms and provisions of the Loan
Documents) to the Administrative Agent on behalf of the Lenders, pursuant to
such documentation as the Lenders deem necessary and appropriate; or

              (b) suffer or permit the issuance of any capital stock of the
Borrowers, except for the issuance of Additional Equity Stock, whether pursuant
to an employee stock option plan or an employee stock ownership plan, in form
and substance reasonably satisfactory to the Administrative Agent (either such
plan being referred to herein as an "Approved ESOP"), an employee stock purchase
plan, in form and substance reasonably satisfactory to the Administrative Agent
(an "Approved ESPP"), a public offering or otherwise; provided that, after
giving effect to such issuance, (i) Pedersen shall own and hold stock
representing at least fifty-one percent (51%) of the voting rights (and both
majority and effective control) of the Parent Company; (ii) stock representing
at least fifty-one percent (51%) of the voting rights (and both majority and
effective control) of any other Borrower in which Additional Equity Stock is
issued shall be owned by the Borrower(s); and (iii) not more than Five Million
and No/100 Dollars ($5,000,000.00) in the aggregate of the Additional Equity
Stock is redeemable; or

              (c) permit any Borrower to sell, assign, loan, deliver, lease,
transfer or otherwise dispose of property or assets (including, without
limitation, stock of another Borrower), except for (i) transfers of assets
between Borrowers in which the Administrative Agent has a perfected security
interest in and to all of their assets constituting Collateral; (ii) the
disposition of a Borrower's assets to a Pedersen Entity, provided that such
entity, upon its acquisition of such assets, becomes a "Borrower" under this
Agreement and the other Loan Documents and pledges all of its assets (of the
kind and nature pledged by the Borrowers

                                       42

<PAGE>

pursuant to the terms and provisions of the Loan Documents) to the
Administrative Agent on behalf of the Lenders pursuant to such documentation as
the Lenders deem necessary and appropriate; (iii) dispositions of the assets of
the Borrowers listed on Schedule 9.1 hereto; and (iv) the disposition of other
                        ------------
assets in the ordinary course of the Borrowers' business, provided that such
dispositions of other assets, in the aggregate, do not exceed the Dollar
Equivalent Amount of Five Hundred Thousand and No/100 Dollars ($500,000.00)
during any twelve (12) month period; or permit any Borrower to become a party to
any document, instrument or agreement (other than this Agreement) which
prohibits such Borrower from assigning, pledging, hypothecating or otherwise
encumbering any stock of another Borrower; or

         (d) permit any Borrower or any subsidiary or affiliate of any Borrower
to merge or consolidate with any company or enterprise, or acquire or purchase
any company or enterprise or acquire or purchase substantially all of the assets
of any company or enterprise; it being understood and agreed that mergers
between Borrowers shall not require the consent of the Administrative Agent so
long as (i) after giving effect to such merger, the Administrative Agent has a
perfected security interest in and to the all of the assets of the surviving
Borrower constituting Collateral, and (ii) the Borrowers shall have provided not
less than twenty (20) days prior written notice to the Administrative Agent and
Lenders of any merger or consolidation between Borrowers, except that written
notice of the proposed merger between the Parent Company and ManTech
International Corporation, a Delaware corporation, may be given within five (5)
days after such merger. In the event that the Administrative Agent issues its
consent to a hostile acquisition or an acquisition involving the stock or assets
of existing customers of any Lender, such consent shall be subject to the
Borrowers' agreement to indemnify, defend and hold the Lenders harmless from and
against any and all claims, demands, losses, liabilities, damages, costs and
expenses of every kind and nature, including without limitation, reasonable
attorneys' fees, related to, arising out of or in connection with such
acquisition, pursuant to an indemnity agreement satisfactory to the Lenders in
all respects. Furthermore, the Borrowers acknowledge and agree that the assets
of the company to be acquired or merged will not be included in the calculation
of the Maximum Borrowing Base without the Administrative Agent's prior approval.

     7.2. Margin Stocks. Use all or any part of the proceeds of any advance made
          -------------
hereunder to purchase or carry, or to reduce or retire any loan incurred to
purchase or carry, any margin stocks (within the meaning of Regulation U of the
Board of Governors of the Federal Reserve System) or to extend credit to others
for the purpose of purchasing or carrying any such margin stocks.

     7.3. Change of Operations. Change the general character of any Borrower's
          --------------------
business as conducted on the Closing Date, or engage in any type of business not
directly related to or compatible with such business as presently and normally
conducted.

     7.4. Judgments; Attachments. Suffer or permit any judgment in excess of the
          ----------------------
Dollar Equivalent Amount of Five Hundred Thousand and No/100 Dollars
($500,000.00) against any Borrower or any attachment against any Borrower's
property (for an amount not fully covered by insurance) to remain unpaid,
undischarged or undismissed for a period of ten (10) days, unless enforcement
thereof shall be effectively stayed or bonded.

                                       43

<PAGE>

     7.5. Further Assignments; Performance and Modification of Contracts; etc.
          --------------------------------------------------------------------
Except as may be expressly permitted by the Loan Documents (i) make any further
assignment, pledge or disposition of the Collateral or any part thereof; (ii)
permit any set-off or reduction, delay the timing of any payment under, or
otherwise modify any Material Contract, if such set-off, reduction, delay or
modification would give rise to a Borrowing Base Deficiency or otherwise
adversely affect any Borrower in any material respect; (iii) create, incur or
permit to exist any lien or encumbrance on any real property now or hereafter
owned by any Borrower; or (iv) do or permit to be done anything to impair the
Administrative Agent's security interest in any Collateral or the payments due
to any Borrower thereunder; it being understood that reasonable and customary
compromises and settlements with Account Debtors in the ordinary course of the
Borrower's business will not constitute a violation of this covenant.

     7.6. Affect Rights of the Administrative Agent or Lenders. At any time do
          ----------------------------------------------------
or perform any act or permit any act to be performed which would or reasonably
could materially adversely affect the interests or rights of the Administrative
Agent or Lenders under any Loan Document.

     7.7. Indebtedness; Granting of Security Interests.
          --------------------------------------------

          (a) Suffer or permit any Borrower to incur any indebtedness, whether
direct or indirect, except for:

               (i)   trade debt and operating leases incurred in the ordinary
course of business;

               (ii)  indebtedness outstanding on the date hereof and listed on
Schedule 7.7(a) hereto;
---------------

               (iii) inter-company indebtedness (including inter-company
guarantees) by and among the Borrowers in which the Administrative Agent has a
perfected security interest in and to all of their assets constituting
Collateral;

               (iv)  performance bonds issued on behalf of the Borrowers in the
ordinary course of business, and performance guarantees issued by any Borrower
for the benefit of another Borrower;

               (v)   indebtedness secured by liens listed on Schedule 7.7(c)
                                                             --------------
hereto, or other indebtedness secured by Permitted Liens;

               (vi)  debt incurred to finance the redemption of not more than
One Million Five Hundred Thousand Dollars ($1,500,000) of the Borrowers
Redeemable Common B Stock, on terms and conditions acceptable to the Lenders in
all respects;

               (vii) subject to the terms and provisions set forth in the letter
agreement dated January 7, 1998 attached as Exhibit 11 hereto, subordinated debt
                                            ----------
(the "First Source Debt") owing to First Source Financial LLP in a principal
amount not to exceed Eight Million and No/100 Dollars ($8,000,000.00); it being
expressly understood and agreed that (a)

                                       44

<PAGE>

the terms of such letter agreement shall be applicable to the Facilities being
made available to the Borrowers pursuant to this Agreement and be for the
benefit of the Lenders in connection with the Facilities (although such letter
agreement was originally executed in connection with, and for the benefit of, a
previous senior credit facility), and (b) in the event of any inconsistency
between the letter agreement and this Agreement, the terms and provisions set
forth in this Agreement shall control;

                (viii) other subordinated debt expressly subordinated to the
Loan on terms and conditions acceptable to the Lenders, provided that, upon
request of the Administrative Agent, the subordinate lender executes a
subordination agreement satisfactory to the Administrative Agent in all
respects;

                (ix)   unfunded retirement plan liabilities of the senior
employee retirement plans of the Parent Company and NSI;

                (x)    indebtedness incurred pursuant to interest rate
contracts entered into by the Borrowers in accordance with Section 6.19 of this
 Agreement;

                (xi)   indebtedness incurred by ARL in the United Kingdom,
provided that such indebtedness is unsecured, used solely for working capital
purposes and does not, at any time, exceed the Dollar Equivalent Amount of One
Million and No/100 Dollars ($1,000,000.00);

                (xii)  indebtedness incurred to finance (by purchase or lease)
equipment constituting capital expenditures, provided that such indebtedness
does not violate any other covenant set forth in this Agreement; and

                (xiii) other guarantees expressly permitted by the terms of this
Agreement.

          (b) mortgage, assign, pledge, hypothecate or otherwise encumber or
permit any lien, security interest or other encumbrance, including purchase
money liens, whether under conditional or installment sales arrangements or
otherwise, to affect the Collateral or any other assets or properties of any
Borrower (except for Permitted Liens and other liens, security interests or
encumbrances expressly permitted herein); or

          (c) enter into any agreement or understanding with any person or
entity pursuant to which any Borrower agrees to be bound by a covenant not to
encumber all or any part of the property or assets of such Borrower, unless such
agreement or understanding is entered into in connection with the granting of
purchase money security interests permitted pursuant to the terms and provisions
of this Agreement.

     Each Borrower hereby agrees that, upon request of the Administrative Agent,
the Borrower shall provide to the Administrative Agent such documents,
instruments and/or agreements evidencing, arising from or related to any and all
performance guarantees executed by any Borrower.

                                       45

<PAGE>

     7.8.   Dividends; Loans; Advances; Investments and Similar Events.
            ----------------------------------------------------------

            (a) Declare or pay any dividend on any Borrower's capital stock of
any class, alter or amend any Borrower's capital structure, purchase, redeem or
otherwise retire any shares of any Borrower's capital stock (other than pursuant
to an Approved ESOP or an Approved ESPP), voluntarily prepay, acquire or
anticipate any sinking fund requirement of any indebtedness, or make any
distributions in cash or assets to any Borrower's shareholders or any Borrower's
affiliate; it being understood and agreed, however, that so long as (i) no Event
of Default shall have occurred, and no act, event or condition shall have
occurred which with notice or the lapse of time, or both, shall constitute an
Event of Default; and (ii) the dividends, distributions and payments authorized
below cannot reasonably be expected to cause any Borrower to be unable to
satisfy the financial covenants set forth in Section 6.15 of this Agreement, the
Borrowers shall be entitled to:

               (i)    pay dividends on the Parent Company's Redeemable Common B
Stock, provided that the dividend rate and aggregate amount of Common B Stock
dividends do not exceed the rates and amounts permitted by the Borrowers'
Certificate of Incorporation, as in effect on the date hereof;

               (ii)   redeem the Parent Company's Redeemable Common B Stock in
connection with 401(k) transactions;

               (iii)  purchase or redeem stock in subsidiaries of the Parent
Company held by minority shareholders, provided that the aggregate purchase
price of all such purchases or redemptions does not, at any time, exceed Two
Million and No/100 Dollars ($2,000,000.00) throughout the term of the Loan; and

               (iv)   pay dividends on any Borrower's capital stock (other than
the Parent Company, as provided above); provided that (A) if the dividends are
payable solely to another Borrower, there shall be no limitation on the amount
paid, and (B) if the dividends are payable to both a Borrower and non-Borrower,
the amount of any and all dividends paid shall not exceed Two Hundred
Seventy-five Thousand and No/100 Dollars ($275,000.00), in the aggregate, per
annum.

            (b) make any loans, salary advances or other payments to (i) any
shareholders of any Borrower, unless such shareholder is also a Borrower party
to this Agreement in which the Administrative Agent has a perfected security
interest in and to all of its assets constituting Collateral at the time such
loan, salary advance or other payment is made; (ii) any corporation or other
enterprise directly or indirectly owned in whole or in part by any shareholder
of any Borrower, unless such corporation or other enterprise is also a Borrower
party to this Agreement in which the Administrative Agent has a perfected
security interest in and to all of its assets constituting Collateral at the
time such loan, salary advance or other payment is made; or (iii) any other
person or entity; provided, however, that the Borrowers may make or continue to
have outstanding any or all of the following:

               (i)    loans or advances to any individual officer, present
employee or former employee of any Borrower of not more than Three Hundred
Thousand and No/100

                                       46

<PAGE>

Dollars ($300,000.00), provided, that all such loans and advances to officers
may not at any time exceed Nine Hundred Thousand and No/100 Dollars
($900,000.00), in the aggregate; it being understood that travel advances made
in the ordinary course of business shall not be included in calculating the
foregoing computation;

               (ii)   loans, advances and/or investments from one Borrower to
another Borrower; provided that (A) the aggregate amount of all loans or
advances to, or net after tax cash investments in Vobix (including direct
borrowings from the Administrative Agent or the Lenders to Vobix) shall not, at
any time, exceed Ten Million and No/100 Dollars ($10,000,000.00), in the
aggregate; (B) the aggregate amount of all loans or advances to, or net after
tax investments in ARL (including direct borrowings from the Administrative
Agent or the Lenders to ARL) shall not, at any time, exceed Six Million and
No/100 Dollars ($6,000,000.00), in the aggregate; and (C) the Administrative
Agent has a perfected security interest in and to all of each Borrower's assets
constituting Collateral;

               (iii)  loans, advances and/or investments in the amounts which
are unpaid or outstanding as of the date hereof and listed on Schedule 7.8(c)
                                                              ---------------
hereto, together with such other loans, advances and/or investments that any
Borrower may hereafter make or extend to any non-Borrower (to the extent such
loans, advances and/or investments are not otherwise addressed in this Section
7.8); provided that (A) all such loans, advances and investments may not at any
time exceed Twelve Million and No/100 Dollars ($12,000,000.00), in the
aggregate; (B) the debt or equity security issued in connection therewith shall
have been pledged to the Administrative Agent, for the benefit of the Lenders,
pursuant to documentation reasonably satisfactory to the Administrative Agent;
and (C) with respect to any loan, advance or investment made after the Closing
Date, the Borrowers shall have maintained excess availability under Facility A,
during the thirty (30) day period immediately preceding the date on which the
particular loan, advance and/or investment is made, in an amount not less than
Seven Million and No/100 Dollars ($7,000,000.00);

               (iv)   trade credit extended to customers of the Borrowers in the
ordinary course of business;

               (v)    Ordinary Course Payments;

               (vi)   negotiable instruments endorsed for deposit or collection
in the ordinary course of business;

               (vii)  securities or certificates of deposit with maturities of
two (2) years or less; provided that, concurrent with such investment, any and
all securities or certificates of deposit (other than those acquired in
connection with RABBI trusts and deferred compensation plans) shall have been
pledged to the Administrative Agent, for the benefit of the Lenders, pursuant to
documentation reasonably satisfactory to the Administrative Agent;

               (viii) with respect to the First Source Debt, (a) regularly
scheduled payments thereof (including payment at maturity), except to the extent
any such payment shall be prohibited pursuant to the First Source Debt Credit
Agreement, and (b) subject to Section 1.5 of this Agreement, the prepayment of
the First Source Debt; provided that such prepayment is

                                       47

<PAGE>

funded solely from the proceeds of an initial public offering expressly
permitted pursuant to Section 7.1(b) of this Agreement; and

               (ix)  so long as no Event of Default shall have occurred and be
continuing, regularly scheduled payments on any other indebtedness expressly
permitted pursuant to Section 7.7 of this Agreement.

     7.9.  Lease Obligations.
           -----------------

           (a) Except as may be expressly permitted by Section 7.7 of this
Agreement, enter into any new lease of real or personal property, except in the
ordinary course of business; or

           (b) enter into any operating lease (other than a lease for real
property) if the aggregate amount of payments due under any and all operating
leases of the Borrower(s) shall, at any time, exceed the Dollar Equivalent
Amount of Four Million Five Hundred Thousand and No/100 Dollars ($4,500,000.00)
during any twelve (12) month period; it being understood and agreed that
payments now or hereafter due in connection with the Enterprise Resource
Planning Operating Lease shall not be included in the foregoing computation so
long as the aggregate amount of such payments does not exceed Eight Million One
Hundred Thousand and No/100 Dollars ($8,100,000.00) throughout the term of the
Loan.

     7.10. Duty Deferment Bond. Modify or amend, in any respect, the Duty
           -------------------
Deferment Bond, without the prior written consent of the Administrative Agent;
it being expressly understood and agreed that the Administrative Agent's consent
shall not be required for any change in the amount of the Duty Deferment Bond so
long as the Borrowers shall have provided to the Administrative Agent not less
than two (2) Business Days' prior written notice of such change, together with a
copy of the proposed amended Duty Deferment Bond.

     7.11. Lockbox Deposits. Permit or cause any and all payments required to be
           ----------------
made directly to the Administrative Agent, pursuant to Section 11.2 of this
Agreement, to be made or directed to any other person or entity, without the
prior approval of the Administrative Agent.

                                    ARTICLE 8
                               COLLATERAL ACCOUNT

     From and after the occurrence of an Event of Default, upon the request of
the Administrative Agent, the Borrowers will deposit or cause to be deposited
into a collateral account (the "Collateral Account") designated by the
Administrative Agent, all checks, drafts, cash and other remittances received by
the Borrowers, and shall deposit such items for credit to the Collateral Account
within one (1) Business Day of the receipt thereof and in precisely the form
received. Pending such deposit, the Borrowers will not commingle any such items
of payment with any of their other funds or property, but will hold them
separate and apart.

     The Borrowers hereby covenant and agree that the Collateral Account shall
secure the Obligations and hereby grants, assigns and transfers to or at the
direction of the Administrative Agent, on behalf of the Lenders, a continuing
security interest in all of the Borrowers' right, title

                                       48

<PAGE>

and interest in and to the Collateral Account, whenever created or established.
Subject to the terms of this Agreement or any other Loan Document, from and
after the occurrence of an Event of Default, the Administrative Agent may apply
funds in the Collateral Account to any of the Obligations, including, without
limitation, any principal, interest or other payment(s) not made when due,
whether arising under this Loan Agreement and/or any other Loan Document, or any
other Obligation of the Borrowers, without notice to the Borrowers, without
regard to the origin of the deposits in the account, the beneficial ownership of
the funds therein or whether such Obligations are owed jointly with another or
severally; the order and method of such application to be in the sole discretion
of the Administrative Agent, subject to the terms of this Agreement and the
other Loan Documents. The Administrative Agent's right to deduct sums due under
the Loan Documents from the Borrowers' account(s) shall not relieve the
Borrowers from their obligation to make all payments required by the Loan
Documents as and when required by the Loan Documents, and the Administrative
Agent shall not have any obligation to make any such deductions or any liability
whatsoever for any failure to do so.

                                   ARTICLE 9
                              DEFAULT AND REMEDIES

        9.1.    Events of Default.  Any one of the following events shall be
                -----------------
considered an "Event of Default":

                (a) if any Borrower shall fail to pay any principal, interest or
other sum owing on any of the Notes or any other Obligation when the same shall
become due and payable, whether by reason of acceleration or otherwise;

                (b) if the Borrowers shall exceed the Maximum Borrowing Base and
fail, immediately upon the happening of such occurrence, without notice or
demand therefor, to make a payment to the Administrative Agent in an amount
equal to or greater than the Borrowing Base Deficiency;

                (c) if any Borrower shall fail to pay and satisfy in full,
within ten (10) days of the rendering thereof, any judgment against any Borrower
in excess of the Dollar Equivalent Amount of Five Hundred Thousand and No/100
Dollars ($500,000.00) which is not, to the reasonable satisfaction of the
Administrative Agent, fully bonded, stayed, covered by insurance or covered by
appropriate reserves;

                (d) if any warranty or representation set forth herein or in any
other Loan Document made by any Borrower or any other party to any of the Loan
Documents shall be misleading or untrue in any material respect when made or
remade;

                (e) if there shall be non-compliance with or a breach of any of
the Affirmative Covenants or Negative Covenants contained in this Agreement, or
any other covenants or agreements of any Borrower or any other person set forth
herein, in any of the Notes or in any other Loan Document;

                (f) if (i) without the prior written consent of the
Administrative Agent, any Borrower (other than the Borrowers listed on Schedule
                                                                       --------
9.1 hereto) shall be liquidated or
---

                                       49

<PAGE>

dissolved or shall discontinue its business; (ii) a trustee or receiver is
appointed for any Borrower or for all or a substantial part of its assets; (iii)
any Borrower makes a general assignment for the benefit of creditors; (iv) any
Borrower files or is the subject of any insolvency proceeding or petition in
bankruptcy, which in the case of an involuntary bankruptcy, remains undismissed
for sixty (60) days; (v) any Borrower (other than the Borrowers listed on
Schedule 5.23 hereto) shall become insolvent or any Borrower shall at any time
-------------
fail generally to pay its debts as such debts become due; or (vi) any
governmental agency or bankruptcy court or other court of competent jurisdiction
shall assume custody or control of the whole or any part of the assets of any
Borrower;

               (g) if any Borrower's property or assets, including, without
limitation, any deposit accounts, are levied upon, attached or subject to any
other enforcement proceeding, which is not fully bonded or stayed;

               (h) the reorganization of any Borrower, without the prior written
consent of the Administrative Agent;

               (i) if any obligation of any Borrower for the payment of borrowed
money, which involves amounts in excess of the Dollar Equivalent Amount of Two
Hundred Fifty Thousand and No/100 Dollars ($250,000.00), whether now existing or
hereafter created, incurred or arising, becomes or is declared to be due and
payable prior to the expressed maturity thereof, whether such obligation is owed
to a Lender or any other person;

               (j) if any Borrower is in default under any contract or
agreement, financial or otherwise, between such Borrower and any other person or
entity, involving amounts in excess of the Dollar Equivalent Amount of Five
Hundred Thousand and No/100 Dollars ($500,000.00), and the other party thereto
commences exercise of its rights and remedies under such contract or agreement
as a consequence of such default; and/or

               (k) if the Required Lenders believe there is a material adverse
change in the business, assets, properties, condition (financial or otherwise)
of the Borrowers, in the aggregate.

          9.2. Remedies. Upon the occurrence of any Event of Default, the
               --------
Administrative Agent, acting on behalf of the Lenders, may exercise any or all
of the following remedies:

               (a) Withhold disbursement of all or any part of the Loan
proceeds;

               (b) Terminate the Lenders' obligation to make further
disbursements of the Loan proceeds;

               (c) Declare all principal, interest and other sums owing on the
Obligations to be immediately due and payable without demand, protest, notice of
protest, notice of default, presentment for payment or further notice of any
kind; provided, however, that payments of amounts hereunder shall not be
accelerated by reason of (i) a default in the payment of any sum due and payable
hereunder or pursuant to any other Loan Document (a "Payment Default"), unless
such Payment Default remains uncured for five (5) days (with no notice of
default being

                                       50

<PAGE>

required); and (ii) a default other than a Payment Default (a "Non-Payment
Default"), unless such Non-Payment Default remains uncured for fifteen (15) days
following notice thereof from the Administrative Agent to the Borrowers.
Notwithstanding the foregoing, no notice of a Non-Payment Default shall be
required prior to acceleration or prior to the Administrative Agent exercising
any other right or remedy under this Agreement or any other Loan Document, if
(i) the Administrative Agent in good faith believes that any such delay would
jeopardize the Lenders' security or the Administrative Agent's or Lenders' lien
priority or (ii) the default is a violation of Section 6.3(c) of this Agreement;

               (d) Without notice, redirect any and all of the Borrowers'
deposits to the Collateral Account;

               (e) Without notice, offset and apply against all or any part of
the Obligations then owing by any Borrower to any Lender, any and all money,
credits, stocks, bonds or other securities or property of any Borrower of any
kind or nature whatsoever on deposit with, held by or in the possession of any
Lender in any capacity whatsoever, including, without limitation, any deposits
with any Lender or any of its affiliates, to the credit of or for the account of
any Borrower. The Administrative Agent and Lenders are authorized at any time to
charge the Obligations against any Borrower's account(s), without regard to the
origin of deposits to the account or beneficial ownership of the funds. Any and
all amounts obtained by the Administrative Agent or any Lender pursuant to this
subsection (e) shall be shared by all of the Lenders ratably, in accordance with
each Lender's Percentage; it being expressly acknowledged and agreed that each
Lender, as well as the Administrative Agent, shall be entitled to exercise the
rights of set-off provided in this subsection (e) of this Section 9.2;

               (f) Exercise all rights, powers and remedies of a secured party
under the UCC and/or any other applicable law(s), including, without limitation,
the right to (i) require any Borrower to assemble the Collateral (to the extent
that it is movable) and make it available to the Administrative Agent at a place
to be designated by the Administrative Agent, and (ii) enter upon any Borrower's
premises, peaceably by the Administrative Agent's own means or with legal
process, and take possession of, render unusable or dispose of the Collateral on
such premises; each Borrower hereby agreeing not to resist or interfere with any
such action. The Administrative Agent agrees to give the Borrowers written
notice of the time and place of any public sale of the Collateral or any part
thereof, and the time after which any private sale or any other intended
disposition of the Collateral is to be made, and such notice will be mailed,
postage prepaid, to the principal place of business of the Borrowers, at least
ten (10) days before the time of any such sale or disposition. Each Borrower
hereby authorizes and appoints the Administrative Agent and its successors and
assigns to (x) sell the Collateral, and (y) declare that each Borrower assents
to the passage of a decree by a court of proper jurisdiction for the sale of the
Collateral. Any such sale pursuant to (x) or (y) above is to be made in
accordance with the applicable provisions of the laws and rules of procedure of
the Commonwealth of Virginia or other applicable law; and/or

               (g) Proceed to enforce such other and additional rights and
remedies as the Administrative Agent and/or Lenders may have hereunder and/or
under any of the other Loan Documents, or as may be provided by applicable law.

                                       51

<PAGE>

         It is expressly understood and agreed that the Lenders and/or the
Administrative Agent may exercise their respective rights under this Agreement
or under any other Loan Document without exercising the rights or affecting the
security afforded by any other Loan Document, and it is further understood and
agreed that the Administrative Agent may proceed against all or any portion of
the Collateral in such order and at such times as the Administrative Agent, in
its sole discretion, sees fit; and each Borrower hereby expressly waives, to the
extent permitted by law, all benefit of valuation, appraisement, marshaling of
assets and all exemptions under the laws of the Commonwealth of Virginia and/or
any other state, district or territory of the United States. Notwithstanding the
foregoing delegation of authority by the Lenders to the Administrative Agent, it
is agreed that at any time there are two (2) or fewer Lender parties to this
Agreement, any Lender may request the Administrative Agent to commence
enforcement action against the Borrowers and/or Collateral upon an Event of
Default. In this event, if the Administrative Agent fails or refuses to take
enforcement action upon the request of a Lender, such Lender may itself commence
appropriate enforcement action. Furthermore, if any Borrower shall default in
the performance when due of any of the provisions of this Agreement, the
Administrative Agent, without notice to or demand upon the Borrowers (and
without any grace or cure period) and without waiving or releasing any of the
Obligations or any default hereunder, under the Notes or under any other Loan
Document, may (but shall be under no obligation to) perform the same for each
Borrower's account, and any monies expended in so doing shall be chargeable to
the Borrowers with interest, at the highest rate of interest payable under
Notes, plus two percent (2%), and added to the indebtedness secured by the
Collateral.

         All sums paid or advanced by the Administrative Agent in connection
with the foregoing or otherwise in connection with the Loan, and all court costs
and expenses of collection, including without limitation, reasonable attorneys'
fees and expenses (and fees and expenses resulting from the taking, holding or
disposition of the Collateral) incurred in connection therewith shall be paid by
the Borrowers upon demand and shall become a part of the Obligations secured by
the Collateral. The Borrowers agree to bear the expense of each lien search,
property and judgment report or other form of Collateral ownership investigation
as the Administrative Agent, in its discretion, shall deem necessary or
desirable to assure or further assure to the Lenders and/or the Administrative
Agent their respective interests in the Collateral.

                                   ARTICLE 10
                               THE AGENTS; AGENCY

         10.1. Appointment. Each Lender hereby affirms its irrevocable
               -----------
appointment of Citizens Bank to act as Administrative Agent and PNC to act as
Documentation Agent for each such Lender pursuant to the provisions of this
Agreement and the other Loan Documents, and affirms its irrevocable
authorization given to the Agents to take such action, and exercise such powers
and perform such duties as are expressly delegated to or required of the Agents
by the terms hereof or thereof, or are reasonably incidental thereto, including
without limitation, executing documents on behalf of the Lenders, as agent.
Citizens Bank affirms its agreement to act as Administrative Agent and PNC
affirms its agreement to act as Documentation Agent on behalf of the Lenders on
the terms and conditions set forth in this Agreement and the other Loan
Documents, subject to their right to resign as provided in Section 10.10. Each
Lender agrees that the rights and remedies granted to the Agents under this
Agreement and the other Loan Documents shall be exercised exclusively by the
Agents, and that no Lender shall have the right

                                       52

<PAGE>

individually to exercise any such right or remedy, except to the extent
expressly provided herein or therein.

     10.2. General Nature of Agents' Duties. Notwithstanding anything to the
           --------------------------------
contrary elsewhere in this Agreement or any other Loan Document:

           (a) The Agents shall have no duties or responsibilities other than
those expressly set forth in this Agreement and the other Loan Documents, and no
implied duties or responsibilities on the part of the Agents shall be read into
this Agreement or any other Loan Document or shall otherwise exist.

           (b) The duties and responsibilities of the Agents under this
Agreement and the other Loan Documents shall be mechanical and administrative in
nature, and the Agents shall not have a fiduciary relationship in respect of any
Lender, except with respect to funds or collateral any Agent receives on behalf
of any Lender.

           (c) Each Agent is and shall be solely the agent of the Lenders. Each
Agent does not assume, and shall not at any time be deemed to have, any
relationship of agency or trust with or for, or any other duty or responsibility
to, any Borrower or any other person (except only for its relationship as agent
for, its express duties and responsibilities as agent for, and its express
duties and responsibilities to, the Lenders as provided in this Agreement and
the other Loan Documents).

           (d) Neither Agent shall be under any obligation to take any action
hereunder or under any other Loan Document if such Agent believes in good faith
that taking such action may conflict with any Applicable Laws, or any provision
of this Agreement or any other Loan Document, or may require the such Agent to
qualify to do business in any jurisdiction where it is not then so qualified.

     10.3. Exercise of Powers.
           ------------------

           (a) The Agents shall have the authority to take any action of the
type specified in this Agreement or any other Loan Document as being within each
Agent's rights, powers or discretion, as it determines in its sole discretion,
except as provided in subsection (b) below, and except as provided in any other
Loan Document which expressly requires the direction or consent of (i) the
Required Lenders; or (ii) all of the Lenders, in either of which circumstances
such Agent shall not take such action absent such direction or consent. Any
action or inaction pursuant to such direction or consent shall be binding on all
of the Lenders.

           (b) The Administrative Agent shall not in any material respect amend,
modify, grant consents or waive any term or provision of this Agreement or any
other Loan Document without the consent or approval of the Required Lenders, or
declare an Event of Default, provide formal written notice of default to any
Borrower or exercise any rights or remedies against any Borrower without the
prior consent of the Required Lenders. Each Lender agrees that its decision to
consent to or reject any request by the Administrative Agent for permission to
declare an Event of Default, provide formal notice thereof to any Borrower
and/or exercise any rights or remedies arising by virtue of such default, shall
be made as soon as

                                       53

<PAGE>

reasonably practicable after the Lender has received all relevant information
with respect to such request, but in all events within five (5) Business Days of
the receipt of such information; it being understood and agreed that, unless
otherwise provided herein, the Administrative Agent shall exercise any and all
rights and responsibilities on behalf of the Lenders in connection with an Event
of Default. Additionally, only with the consent or approval of all of the
Lenders, the Administrative Agent may (a) extend the final maturity of the Loan
or any Note, reduce the interest rate payable on or extend the time of payment
for any installment of principal, interest or fees payable in connection with
the Loan, or issue Letters of Credit (i) having an expiration date beyond the
Maturity Date, except as otherwise expressly provided in this Agreement, or (ii)
causing the aggregate outstanding amount of all such Letters of Credit issued to
exceed Ten Million Dollars ($10,000,000); (b) change the Percentage of the
Commitment Amount of any Lender, (c) release all or a substantial portion of the
Collateral, except in accordance with the provisions of any applicable Loan
Document, (d) amend the definition of the Required Lenders or expand the
definitions of Eligible Billed Government Accounts Receivable, Eligible Billed
Commercial Accounts Receivable and/or Eligible Unbilled Government Accounts
Receivable, (e) consent to the assignment or transfer by any Borrower of any of
its rights or obligations hereunder, (f) amend, modify or waive any provisions
of this Section 10.3, (g) change the manner of application by the Administrative
Agent of payments made under the Loan Documents, or (h) change the method of
calculation used in connection with the computation of interest, commissions or
fees. Each Lender agrees that its decision to approve or reject any request for
an amendment or waiver with respect to this Agreement shall be made as soon as
reasonably practicable after the Lender has received all relevant information
with respect to such request.

         10.4. General Exculpatory Provisions. Notwithstanding anything to the
               ------------------------------
contrary elsewhere in this Agreement or any other Loan Document:

               (a) Neither Agent, in its capacity as Agent (but not as a
Lender), shall be liable for any action taken or omitted to be taken by it under
or in connection with this Agreement or any other Loan Document, unless caused
by its own gross negligence or willful misconduct.

               (b) Neither Agent shall be responsible for (i) the execution,
delivery, effectiveness, enforceability, genuineness, validity or adequacy of
this Agreement or any other Loan Document, (ii) any recital, representation,
warranty, document, certificate, report or statement in this Agreement or any
other Loan Document, (iii) any failure of any Borrower or any Lender to perform
any of their respective obligations under this Agreement or any other Loan
Document, (iv) the existence, validity, enforceability, perfection, recordation,
priority, adequacy or value, now or hereafter, of any lien or encumbrance or
other direct or indirect security afforded or purported to be afforded by any of
the Loan Documents, or otherwise from time to time, or (v) caring for,
protecting, insuring or paying any taxes, charges or assessments with respect to
any Collateral.

               (c) Neither Agent shall be under any obligation to ascertain,
inquire or give any notice relating to (i) the performance or observance of any
of the terms or conditions of this Agreement or any other Loan Document on the
part of any Borrower, (ii) the business,

                                       54

<PAGE>

operations, condition (financial or otherwise) or prospects of any Borrower, or
(iii) except to the extent as may be set forth in Article 9 hereof, the
existence of any Event of Default.

           (d) Neither Agent shall be under any obligation, either initially or
on a continuing basis, to provide any Lender with any notices, reports or
information of any nature, whether in its possession presently or hereafter,
except for such notices, reports and other information expressly required by
this Agreement or any other Loan Document to be furnished by the Agent to such
Lender.

     10.5. Administration by the Agent.
           ---------------------------

           (a) Each Agent may rely upon any notice or other communication of any
nature (written or oral, including telephone conversations, whether or not such
notice or other communication is made in a manner permitted or required by this
Agreement or any other Loan Document) purportedly made by or on behalf of the
proper party or parties, and neither Agent shall have any duty to verify the
identity or authority of any person giving such notice or other communication.

           (b) Each Agent may consult with legal counsel (including in-house
counsel for such Agent), independent public accountants and any other experts
selected by such Agent from time to time, and neither Agent shall be liable for
any action taken or omitted to be taken in good faith by it in accordance with
the advice of such counsel, accountants or experts.

           (c) Each Agent may conclusively rely upon the truth of the statements
and the correctness of the opinions expressed in any certificates or opinions
furnished to such Agent in accordance with the requirements of this Agreement or
any other Loan Document. Whenever either Agent shall deem it necessary or
desirable that a matter be proved or established with respect to any Borrower or
any Lender, such matter may be established by a certificate of such Borrower or
such Lender, as the case may be, and such Agent may conclusively rely upon such
certificate.

           (d) Each Agent may fail or refuse to take any action unless it shall
be indemnified to its satisfaction from time to time against any and all
amounts, liabilities, obligations, losses, damages, penalties, actions,
judgments, suits, costs, expenses and disbursements of every kind and nature
which may be imposed on, incurred by or asserted against such Agent by reason of
taking or continuing to take any such action; provided that no Lender shall be
obligated to indemnify such Agent for any portion of such amounts, liabilities,
obligations, losses, damages, penalties, actions, judgments, suits, costs,
expenses and disbursements resulting solely from the gross negligence or willful
misconduct of such Agent, as finally determined by a court of competent
jurisdiction.

           (e) Each Agent may perform any of its duties under this Agreement or
any other Loan Document by or through agents or attorneys-in-fact. Neither Agent
shall be responsible for the negligence or misconduct of any agents or
attorneys-in-fact selected by it with reasonable care.

                                       55

<PAGE>

              (f) Neither Agent shall be deemed to have any knowledge or notice
of the occurrence of any Event of Default (other than a default in the payment
of regularly scheduled principal or interest), unless such Agent has received
from a Lender or a Borrower a written notice referring to this Agreement,
describing the Event of Default, and stating that such notice is a "notice of
default". If either Agent receives such a notice, such Agent shall give prompt
notice thereof to each Lender.

              (g) The Administrative Agent shall provide three (3) Business Days
prior notice to the Lenders of any field audit scheduled to be performed by the
Administrative Agent pursuant to Section 1.6 of this Agreement. The Lenders
shall be entitled to (i) receive copies of field audits performed by the
Administrative Agent, and (ii) accompany the Administrative Agent to any field
audit, provided that the Administrative Agent may, in its discretion, limit the
number of Lenders attending any such field audit.

         10.6. Lenders Not Relying on Agent or Other Lenders. Each Lender
               ---------------------------------------------
acknowledges as follows:

               (a) Neither Agent nor any other Lender has made any
representations or warranties to it, and no act taken hereafter by either Agent
or any other Lender shall be deemed to constitute any representation or warranty
by such Agent or such other Lender to it.

               (b) It has, independently and without reliance upon either Agent
or any other Lender, and based upon such documents and information as it has
deemed appropriate, made its own credit and legal analysis and decision to enter
into this Agreement and the other Loan Documents.

               (c) It will, independently and without reliance upon either Agent
or any other Lender, and based upon such documents and information as it shall
deem appropriate at the time, make its own decisions to take or not take action
under or in connection with this Agreement and the other Loan Documents.

         10.7. Indemnification. Each Lender agrees to reimburse and indemnify
               ---------------
each Agent and each Agent's directors, officers, employees and agents (to the
extent not reimbursed by the Borrowers, and without limitation of the obligation
of the Borrowers to do so), ratably in accordance with each Lender's Percentage,
from and against any and all amounts, losses, liabilities, claims, damages,
expenses, obligations, penalties, actions, judgments, suits, costs and
disbursements of every kind or nature (including the reasonable fees and
disbursements of counsel for each Agent or such other person in connection with
any investigative, administrative or judicial proceeding commenced or
threatened, whether or not either Agent or such other person shall be designated
a party thereto) that may at any time be imposed on, incurred by or asserted
against such Agent or such other person as a result of this Agreement, any other
Loan Document, any transaction from time to time contemplated hereby or thereby,
or any transaction financed in whole or in part or directly or indirectly with
the proceeds of the Loan; provided that no Lender shall be obligated to
                          --------
indemnify such Agent or such other person for any portion of such amounts,
losses, liabilities, claims, damages, expenses, obligations, penalties, actions,
judgments, suits, costs or disbursements resulting solely from the gross
negligence or willful

                                       56

<PAGE>

misconduct of the person seeking indemnity, as finally determined by a court of
competent jurisdiction.

         10.8.  Agent in its Individual Capacity; Agents' Commitment.
                ----------------------------------------------------

                (a) With respect to their commitments and the Obligations owing
to them, Citizens Bank and PNC shall have the same rights and powers under this
Agreement and each other Loan Document as any other Lender, and may exercise the
same as though they were not the Agents. The terms "Lender," "holders of Notes"
and like terms shall include Citizens Bank and PNC in their individual
capacities. Citizens Bank and PNC and their respective affiliates may, without
liability to account for, make loans to, accept deposits from, acquire debt or
equity interests in, act as trustee under indentures of and engage in any other
business with any Borrower and any stockholder, subsidiary or affiliate of any
Borrower, as though Citizens Bank and PNC were not the Agents hereunder.

                (b) The Administrative Agent hereby agrees that it shall at all
times maintain, at a minimum, the lesser of (the "Agent's Commitment"):

                        (i)  a Ten Million and No/100 Dollar ($10,000,000.00)
interest in the aggregate Commitment Amount; or

                        (ii) a Percentage of the Commitment Amount that is at
least equal to ten percent (10%).

In the event the Administrative Agent fails to maintain the Agent's Commitment,
the Administrative Agent agrees to resign as the Administrative Agent hereunder,
if requested by the Borrowers, pursuant to Section 10.10 of this Agreement; it
being expressly acknowledged and agreed that the Borrowers shall be third party
beneficiaries of the Agent's Commitment requirement set forth in this Section
10.8(b).

         10.9.  Holders of Notes. The Administrative Agent may deem and treat
                ----------------
any Lender which is the payee of a Note as the owner and holder of such Note for
all purposes hereof unless and until written notice evidencing such transfer
shall have been filed with the Administrative Agent. Any authority, direction or
consent of any person who at the time of giving such authority, direction or
consent was a Lender shall be conclusive and binding on each present and
subsequent holder, transferee or assignee of any Note or Notes payable to such
Lender or issued in exchange therefor.

         10.10. Successor Agent. Either Agent may resign at any time by giving
                ---------------
thirty (30) days prior written notice thereof to the Lenders and Borrowers,
subject to appointment of a successor Agent (and such appointees acceptance of
appointment) as below provided in this Section 10.10. Additionally, either Agent
may be removed for cause by all of the Lenders (other than such Agent, if such
Agent is then a Lender), or the Borrowers may request an Agent's resignation
pursuant to Section 10.8(b), if removal or resignation, as applicable, is
requested in writing (which wording must specifically identify the "cause" for
removal), and ten (10) days' prior written notice of removal or resignation is
provided to such Agent and Borrowers (or Lenders, if applicable). Upon any such
resignation or removal, the Lenders shall appoint the

                                       57

<PAGE>

other Agent as the successor Documentation Agent or Administrative Agent, as the
case may be. All references to the "Agents" in the Loan Documents shall be
deemed to mean the person(s) acting as the Documentation Agent and
Administrative Agent, and it is understood that it is possible that the same
person may be acting in both capacities. If such other Agent fails or refuses to
accept such appointment within thirty (30) days after such notice of resignation
or removal, then the retiring Agent shall, on behalf of the Lenders, immediately
appoint, as its successor, another Lender; provided that such Lender is a
commercial bank or trust company organized under the laws of the United States
of America or any State thereof and has a combined capital and surplus of at
least One Billion and No/100 Dollars ($1,000,000,000.00). In such event, the
Agent's resignation or removal shall not be effective until the successor Agent
shall have accepted its appointment. Upon the acceptance by a successor Agent of
its appointment as Agent hereunder, such successor Agent shall thereupon succeed
to and become vested with all of the properties, rights, powers, privileges and
duties of the former Agent, without further act, deed or conveyance. Upon the
effective date of resignation or removal of a retiring Agent, such Agent shall
be discharged from its duties under this Agreement and the other Loan Documents,
but the provisions of this Agreement shall continue to be binding on and inure
to its benefit as to any actions taken or omitted by it while it was Agent under
this Agreement. If for any reason, at any time, there is no Administrative Agent
hereunder, then during such period, the Required Lenders shall have the right to
exercise the Administrative Agent's rights and perform its duties hereunder,
except that (i) all notices or other communications required or permitted to be
given to the Administrative Agent shall be given to each Lender, and (ii) all
payments to be made to the Administrative Agent shall be made directly to the
Borrowers or the Lender for whose account such payment is made.

     10.11. Additional Agents. If the Administrative Agent shall from time to
            -----------------
time deem it necessary or advisable to engage other agents for its own
protection in the performance of its duties hereunder or in the interests of the
Lenders, then the Administrative Agent and Borrowers shall execute and deliver a
supplemental agreement and all other instruments and agreements necessary or
advisable, in the opinion of the Administrative Agent, to constitute another
commercial bank or trust company, or one or more other persons approved by the
Administrative Agent, to act as co-Agent or a separate agent with respect to any
part of the Collateral, with such powers as may be provided in such supplemental
agreement, and with the power to vest in such bank, trust company or other
person (as such co-Agent or separate agent, as the case may be), any properties,
rights, powers, privileges and duties of the Administrative Agent under this
Agreement or any other Loan Document.

     10.12. Calculations. Neither Agent shall be liable for any calculation,
            ------------
apportionment or distribution of payments made by it in good faith. If such
calculation, apportionment or distribution is subsequently determined to have
been made in error, the sole recourse of any Lender to whom payment was due but
not made shall be to recover from the Lenders any payment in excess of the
amount to which they are determined to be entitled, with interest thereon at the
Federal Funds Rate, or, if the amount due was not paid by any Borrower, to
recover such amount from such Borrower, with interest thereon at the rate
provided in the applicable Note.

                                       58

<PAGE>

         10.13. Funding by the Administrative Agent.
                -----------------------------------

                (a) Except as otherwise provided in this Agreement, the
Administrative Agent alone shall be entitled to make all advances in connection
with the Loan and shall receive all payments and other receipts relating to the
Loan; it being understood, however, that the Administrative Agent has reserved
the right not to advance any amounts to the Borrowers which the Administrative
Agent has not received from the Lenders. The Administrative Agent will notify
each Lender of the date and amount of any requested advance, and if such
notification is received by 1:00 p.m. Washington, D.C. time on any given
Business Day, the Lenders shall provide the required funds to the Administrative
Agent no later than the close of business on such Business Day. Once per week,
or within such shorter time frame as may be requested by the Administrative
Agent, the Administrative Agent and each Lender shall pay to each other such
amounts (the "Equalization Payments") as may be necessary to cause each Lender
to own its applicable Percentage of the Loan and otherwise implement the terms
and provisions of this Agreement; it being understood that each Lender shall be
entitled to receive interest on amounts advanced by it only from the date of
such Lender's advance of funds. The obligation of the Administrative Agent and
each Lender to make Equalization Payments shall not be affected by a bankruptcy
filing by any Borrower, the occurrence of any Event of Default or any other act,
occurrence or event whatsoever, whether the same occurs, before, on or after the
date on which an Equalization Payment is required to be made. All Equalization
Payments shall be made by 1:00 p.m. Washington, D.C. time on the date such
payment is required.

                (b) Unless the Administrative Agent shall have been notified in
writing by any Lender no later than the close of business on the Business Day
before the Business Day on which an advance requested by the Borrowers is to be
made, that such Lender will not make its ratable share of such advance, the
Administrative Agent may assume that such Lender will make its ratable share of
the advance, and in reliance upon such assumption the Administrative Agent may
(but in no circumstances shall be required to) make available to the Borrowers a
corresponding amount. If and to the extent that any Lender fails to make such
payment to the Administrative Agent when required, such Lender shall pay such
amount on demand (or, if such Lender fails to pay such amount on demand, the
Borrowers shall arrange for the repayment of such amount to the Administrative
Agent), together with interest for the Administrative Agent's own account for
each day from and including the date of the Administrative Agent's payment, to
and including the date of repayment to the Administrative Agent (before and
after judgment). Interest (a) if paid by such Lender (i) for each day from and
including the date of the Administrative Agent's payment to and including the
second Business Day thereafter, shall accrue at the Federal Funds Rate for such
day, and (ii) for each day thereafter, shall accrue at the rate or rates per
annum payable under the Notes; and (b) if paid by the Borrowers, shall accrue at
the rate or rates per annum payable under the Notes. All payments to the
Administrative Agent under this Section shall be made to the Administrative
Agent at its office set forth in the preamble of this Agreement (or as otherwise
directed by the Administrative Agent), in dollars, in immediately available
funds, without set-off, withholding, counterclaim or other deduction of any
nature.

                (c) All borrowings under this Agreement shall be incurred from
the Lenders pro rata on the basis of their respective Percentages (except to the
extent advanced (i) as a Swing

                                       59

<PAGE>

Line Loan, or (ii) by the Administrative Agent on behalf of any Lender as
provided in subsection (a) or (b) above). It is understood that no Lender shall
be responsible for any other Lender's failure to meet its obligation to make
advances hereunder, and that each Lender shall be obligated to make advances
required to be made by it hereunder regardless of the failure of any other
Lender to make its advances hereunder.

            (d) Each payment and prepayment received by the Administrative Agent
for the account of the Lenders shall be distributed first to the Swing Line
Lender for application to any Swing Line Outstandings, and then to each Lender
entitled to share in such payment, ratably in accordance with each Lender's
Percentage. Notwithstanding the provisions of Section 9.2(d) of this Agreement,
any Lender who has failed to fund its Percentage of any advance under the Loan
shall not be entitled to share in any such payment(s) until such time as the
funding deficiency caused thereby, together with interest thereon (as provided
in subsection (b) above), has been paid to the Administrative Agent in
accordance with the terms and conditions of this Agreement. Payments from the
Administrative Agent to the Lenders shall be made by wire transfer in accordance
with written instructions provided to the Administrative Agent by the Lenders
from time to time. Unless the Administrative Agent shall have received notice
from the Borrowers prior to the date on which any payment is due to the Lenders
hereunder that the Borrowers will not make such payment in full, the
Administrative Agent may assume that the Borrowers have made such payment in
full on such date and the Administrative Agent, in reliance upon such
assumption, may cause to be distributed to each Lender on such due date an
amount equal to the amount then due such Lender. If and to the extent the
Borrowers shall not have made such payment in full to the Administrative Agent,
each Lender shall repay to the Administrative Agent upon its demand therefor
such amount distributed to such Lender, together with interest thereon at the
overnight Federal Funds Rate for each day from the date such amount is
distributed to such Lender until the date such Lender repays such amount to the
Administrative Agent.

            (e) If any Lender shall obtain any payment (whether voluntary,
involuntary, through the exercise of any right of setoff, or otherwise) in
excess of such Lender's Percentage of payments, such Lender shall forthwith
purchase from the other Lender(s) such participations in the Loans made by them
as shall be necessary to cause such purchasing Lender to share the excess
payment ratably with each of the other Lender(s); provided, however, if all or
any portion of such excess payment is thereafter recovered from such purchasing
Lender, such purchase from the other Lender(s) shall be rescinded and each other
Lender shall repay to the purchasing Lender the purchase price to the extent of
such recovery, together with an amount equal to such Lender's ratable share
(according to the proportion of (1) the amount of such Lender's required
repayment, to (2) the total amount so recovered from the purchasing Lender) of
any interest or other amount paid or payable by the purchasing Lender in respect
of the total amount recovered. Each Borrower agrees that any Lender purchasing a
participation from another Lender pursuant to this Section 10.13(e), to the
fullest extent permitted by law, may exercise all of its rights of payment with
respect to such participation as fully as if such Lender were the direct
creditor of the Borrowers in the amount of such participation.

     10.14. Benefit of Article. The provisions of this Article 10 are solely for
            ------------------
the benefit of the Agents and Lenders. Except as provided in Section 10.8(b) of
this Agreement, no Borrower shall have any rights under any of the provisions of
this Article 10; it being understood

                                       60

<PAGE>

that the provisions of this Article 10 are not in limitation of any right,
power, duty, obligation or liability which the Agents would have to or against
any Borrower.

                                   ARTICLE 11
                          CERTAIN ADDITIONAL RIGHTS AND
                      OBLIGATIONS REGARDING THE COLLATERAL

     11.1. Power of Attorney. Each Borrower hereby reaffirms its irrevocable
           -----------------
appointment of the Administrative Agent, as its agent and attorney-in-fact, with
power of substitution, having full power and authority, in its own name, in the
name of any Lender(s), in the name of any Borrower or otherwise (but at the cost
and expense of the Borrowers and without notice to any Borrower), but only after
the occurrence of an Event of Default which remains uncured beyond any
applicable notice and grace period, to (i) notify account debtors obligated on
any of the Receivables to make payments thereon directly to the lockbox
referenced in Section 11.2 of this Agreement, and to take control of the cash
and non-cash proceeds of any such Receivables; (ii) compromise, extend or renew
any of the Collateral constituting Receivables or deal with any of the
Collateral as the Administrative Agent may deem advisable; (iii) release its
interest in, make exchanges or substitutions for and/or surrender, all or any
part of any Borrower's interest in all or any part of the Collateral; (iv)
remove from any Borrower's place(s) of business all books, records, ledger
sheets, correspondence, invoices and documents relating to or evidencing any of
the Collateral, or without cost or expense to the Administrative Agent, make
such use of any Borrower's place(s) of business as may be reasonably necessary
to administer, control and/or collect the Collateral; (v) repair, alter or
supply goods, if any, necessary to fulfill in whole or in part the purchase
order of any Account Debtor; (vi) demand, collect receipt for and give renewals,
extensions, discharges and releases of all or any part of the Collateral; (vii)
institute and prosecute legal and equitable proceedings to enforce collection
of, or realize upon, all or any part of the Collateral; (viii) settle, renew,
extend, compromise, compound, exchange or adjust claims with respect to all or
any part of the Collateral or any legal proceedings brought with respect
thereto; and (ix) receive and open all mail addressed to any Borrower, and
notify the Post Office authorities to change the address for the delivery of
mail to any Borrower to such address as the Administrative Agent may designate;
it being understood that the rights granted to the Administrative Agent in this
clause (ix), which are operative on the occurrence of an Event of Default, shall
not in any way limit or impair the other rights provided to the Administrative
Agent and/or Lenders in this Agreement or any other Loan Document, including,
without limitation, their rights with respect to the Collateral Account and the
below-referenced lockbox. Furthermore, each Borrower hereby reaffirms its
irrevocable appointment of the Administrative Agent, as its agent and
attorney-in-fact, with power of substitution, having full power and authority,
in its own name, in the name of any Lender(s), in the name of any Borrower or
otherwise (but at the cost and expense of the Borrowers and without notice to
any Borrower) and regardless of whether an Event of Default has occurred or any
act, event or condition which with notice or the lapse of time, or both, would
constitute an Event of Default has occurred, to (a) file financing statements
and continuation statements covering the Collateral and execute the same on
behalf of any Borrower; (b) charge against any banking account of any Borrower
any item of payment credited to any Borrower's account which is dishonored by
the drawee or maker thereof; and/or (iii) endorse the name of any Borrower upon
any items of payment relating to the Collateral or upon any proof of claim in
bankruptcy against any Account Debtor.

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<PAGE>

     11.2. Lockbox. Each Borrower hereby authorizes the Administrative Agent to
           -------
receive and collect any amount or amounts due or to become due on account of any
Receivables and, at its discretion, to apply the same to the repayment of the
Notes, and each Borrower agrees that, as of the date hereof, it has established
and shall continually maintain on terms and conditions satisfactory to the
Administrative Agent in all respects, one or more lockboxes (and, if required by
the Administrative Agent, one or more blocked accounts) for the collection of
Receivables. Except as otherwise may be approved by the Administrative Agent in
writing, any checks or other remittances received by any Borrower in payment of
the Receivables shall be held in trust by each Borrower for the Administrative
Agent and Lenders. Each Borrower shall, within thirty (30) days from the date
hereof (or within such longer period as may be reasonably required by any
Borrower), direct all of its customers (other than certain customers as may be
approved by the Administrative Agent) to make payments directly to the
Administrative Agent, and/or include on all of its invoices, a direction to its
customer to make all payments directly to the Administrative Agent, at:

           ManTech International Corporation
           P.O. Box 7777-W2155
           Philadelphia, Pennsylvania  19175-2155

     11.3. Other Agreements. Except as may otherwise be expressly permitted by
           ----------------
the terms of this Agreement, and without limiting any other restrictions or
provisions of this Agreement, each Borrower will (i) on demand, subject to any
confidentiality and secrecy requirements imposed by any Government agency, make
available in form reasonably acceptable to the Administrative Agent, shipping
documents and delivery receipts evidencing the shipment of goods which gave rise
to the sale or lease of inventory or of an account, contract right or chattel
paper, completion certificates or other proof of the satisfactory performance of
services which gave rise to the sale or lease of inventory or of an account,
contract right or chattel paper, and each Borrower's copy of any written
contract or order from which a sale or lease of inventory, an account, contract
right or chattel paper arose; and (ii) when requested, advise the Administrative
Agent when an Account Debtor returns or refuses to retain any goods, the sale or
lease of which gave rise to an account, contract right or chattel paper, and of
any delay in delivery or performance, or claims made in regard to any sale or
lease of inventory, account, contract right or chattel paper. Upon reasonable
notice, all such records will be available for examination by authorized agents
of the Administrative Agent.

     It is expressly understood and agreed, however, that the Administrative
Agent shall not be required or obligated in any manner to make any inquiries as
to the nature or sufficiency of any payment received by it or to present or file
any claims or take any other action to collect or enforce a payment of any
amounts which may have been assigned to it or to which it or the Lenders may be
entitled hereunder at any time or times.

                                   ARTICLE 12
                                  MISCELLANEOUS

     12.1. Remedies Cumulative. Each right, power and remedy of the Agents or
           -------------------
Lenders provided for in this Agreement or in any other Loan Document or now or
hereafter existing at law or in equity, by statute or otherwise, shall be
cumulative and concurrent and shall

                                       62

<PAGE>

be in addition to every other right, power or remedy provided for in this
Agreement or in any other Loan Document, or now or hereafter existing at law or
in equity, by statute or otherwise, and the exercise or beginning of the
exercise by the Agents of any one or more of such rights, powers or remedies
shall not preclude the simultaneous or later exercise by the Agents of any or
all such other rights, powers or remedies.

     12.2. Waiver. Time is of the essence of this Agreement. No failure or delay
           ------
by the Administrative Agent to insist upon the strict performance of any term,
condition, covenant or agreement set forth in this Agreement or any other Loan
Document, or to exercise any right, power or remedy consequent upon a breach
thereof, shall constitute a waiver of such term, condition, covenant or
agreement or of any such breach, or preclude the Administrative Agent from
exercising any such right, power or remedy at any later time or times. By
accepting payment after the due date of any of the Obligations, neither the
Lenders nor the Administrative Agent shall be deemed to have waived either the
right to require prompt payment when due of all other Obligations, or the right
to declare a default for failure to make payment of any such other Obligations.

     12.3. Notices. Notices to either party shall be in writing and shall be
           -------
delivered personally or by first-class mail or nationally-recognized overnight
delivery service addressed to the parties at the addresses set forth below or
otherwise designated in writing:

         If to the Borrowers:   ManTech International Corporation
                                12015 Lee Jackson Highway
                                Fairfax, Virginia 22033
                                Attention: Ms. Tracy A. Wilson

         If to the Lenders:     Citizens Bank of Pennsylvania
                                8521 Leesburg Pike
                                Suite 405
                                Vienna, Virginia 22182
                                Attention: Ms. Maria A. Josephs

                                PNC Bank, National Association
                                One PNC Plaza
                                6th floor
                                249 Fifth Avenue
                                Pittsburgh, Pennsylvania 15222
                                Attention: Ms. Doreen K. Casey

                                Branch Banking and Trust Company of Virginia
                                8200 Greensboro Drive
                                Suite 250
                                McLean, Virginia 22102
                                Attention: Mr. Ronald P. Gudbrandsen

                                and

                                       63

<PAGE>
                                      Chevy Chase Bank, F.S.B.
                                      Government Contracting & Technology Group
                                      7501 Wisconsin Avenue
                                      12th Floor
                                      Bethesda, Maryland 20814
                                      Attention: Ms. Marsha Thompson

         If to the Administrative     Citizens Bank
         Agent:                       8521 Leesburg Pike
                                      Suite 405
                                      Vienna, Virginia 22182
                                      Attention: Ms. Maria A. Josephs

         If to the Documentation      PNC Bank, National Association
         Agent:                       One PNC Plaza
                                      6th floor
                                      249 Fifth Avenue
                                      Pittsburgh, Pennsylvania 15222
                                      Attention: Ms. Doreen Casey

         with a copy of all notices
         to any Lender or Agent to:   Dickstein Shapiro Morin & Oshinsky LLP
                                      2101 L Street, N.W.
                                      Washington, D.C.  20037
                                      Attention: Matthew S. Bergman, Esq.

         with a copy of all notices
         to any Borrower to:          Golden & Nelson, PLLC
                                      8285 Highglade Ct.
                                      Millersville, Maryland 21108
                                      Attention:  Hedy L. Nelson, Esq.

     12.4. Entire Agreement. This Agreement and the other Loan Documents
           ----------------
constitute the entire agreement of the parties with respect to the Loan and
shall continue in full force and effect for so long as any Borrower shall be
indebted hereunder or under any Note, and thereafter until the Administrative
Agent shall have actually received written notice of the termination hereof from
the Borrowers, all Letters of Credit shall have been cancelled or expired and
all Obligations incurred or contracted before receipt of such notice shall have
been fully paid.

     12.5. Relationship of the Parties. This Agreement provides for the
           ---------------------------
extension of financial accommodations by each Lender, in its capacity as lender,
to the Borrowers, in their capacity as borrowers, and for the payment of
interest and repayment of the Obligations by the Borrowers. Certain provisions
herein, such as those relating to compliance with the financial covenants,
delivery to the Administrative Agent and Lenders of financial statements, and
compliance with other affirmative and negative covenants are for the benefit of
the Administrative Agent and Lenders to protect the Lenders' interests in
assuring repayment of the

                                       64

<PAGE>

Obligations. Nothing contained in this Agreement shall be construed as
permitting or obligating the Lenders or Agents to act as a financial or business
advisor or consultant to any Borrower, as permitting or obligating the Lenders
or Agents to control any Borrower or to conduct any Borrower's operations, as
creating any fiduciary obligation on the part of any Lender or Agent to any
Borrower, or as creating any joint venture, agency or other relationship between
the parties other than as explicitly and specifically stated in this Agreement.
Each Borrower acknowledges that it has had the opportunity to obtain the advice
of experienced counsel of its own choosing in connection with the negotiation
and execution of this Agreement and to obtain the advice of such counsel with
respect to all matters contained herein, including, without limitation, the
provision in this Agreement for waiver of trial by jury. Each Borrower further
acknowledges that it is experienced with respect to financial and credit matters
and has made its own independent decision to request the Obligations and execute
and deliver this Agreement.

     12.6. Waiver of Jury Trial. Each Borrower hereby (a) covenants and agrees
           --------------------
not to elect a trial by jury of any issue triable by a jury, and (b) waives any
right to trial by jury fully to the extent that any such right shall now or
hereafter exist. This waiver of right to trial by jury is separately given by
each Borrower, knowingly and voluntarily, and this waiver is intended to
encompass individually each instance and each issue as to which the right to a
jury trial would otherwise accrue. The Administrative Agent is hereby authorized
and requested to submit this Agreement to any court having jurisdiction over the
subject matter and the parties hereto, so as to serve as conclusive evidence of
each Borrower's herein contained waiver of the right to jury trial. Further,
each Borrower hereby certifies that no representative or agent of the Agents or
any Lender (including the Agents' counsel) has represented, expressly or
otherwise, to the undersigned that the Agents or Lenders will not seek to
enforce this provision waiving the right to a trial by jury.

     12.7. Submission to Jurisdiction; Service of Process; Venue. Any judicial
           -----------------------------------------------------
proceeding brought against any Borrower with respect to this Agreement or any
other Loan Document may be brought in any court of competent jurisdiction in the
Commonwealth of Virginia, and by execution and delivery of this Agreement, each
Borrower accepts for itself and in connection with its properties, generally and
unconditionally, the non-exclusive jurisdiction of the aforesaid court, and
irrevocably agrees to be bound by any judgment rendered by such court in
connection with this Agreement. Each Borrower irrevocably designates and
appoints Jeffrey S. Brown, Esq., whose address is 12015 Lee Jackson Highway,
Eighth Floor, Fairfax, Virginia 22033, as its agent to receive on its behalf
service of all process in any such proceeding in any court in the Commonwealth
of Virginia, such service being hereby acknowledged by each Borrower to be
effective and binding on it in every respect. A copy of any such process so
served shall be mailed by registered or certified mail to the Borrower at the
address to which notices are to be addressed in accordance with this Agreement,
except that any failure to mail such copy shall not affect the validity of
service of process. Each Borrower shall at all times maintain an agent for
service of process pursuant to this provision. If any Borrower fails to appoint
such an agent, or if such agent refuses to accept service, such Borrower hereby
agrees that service upon it by mail shall constitute sufficient notice. Nothing
herein shall affect the right to serve process in any other manner permitted by
law or shall limit the right of the Administrative Agent or Lenders to bring
proceedings against any Borrower in the courts of any other jurisdiction.

                                       65

<PAGE>

     12.8.  Changes in Capital Requirements. If after the date of this Agreement
            -------------------------------
the Administrative Agent shall determine that the adoption of any applicable
law, rule or regulation regarding capital adequacy, or any change therein, or
any change in the interpretation or administration thereof, or compliance by the
Lenders with any request or directive regarding capital adequacy of any
authority, central bank or comparable agency, which adoption, change or
compliance is applicable to all banks generally or to banks similar in size, has
or would have the effect of reducing the rate of return on the Lenders' capital
as a consequence of the Lenders' obligations hereunder to a level below that
which the Lenders could have achieved but for such adoption, change or
compliance (taking into consideration the Administrative Agent's policies with
respect to capital adequacy), then, after sixty (60) days prior notice given by
the Administrative Agent to the Borrowers, the interest rate on the Notes shall
be increased to a rate which shall retain the Lenders' original rate of return
on the Lenders' capital.

     12.9.  Captions. The paragraph headings of this Agreement are for
            --------
convenience of reference only, and in no way define, limit or describe the scope
of this Agreement or the intent of any provision hereof.

     12.10. Modification and Waiver. Neither this Agreement nor any term,
            ------------------------
condition, covenant or agreement hereof may be changed, waived, discharged or
terminated orally, but that may be accomplished only by an instrument in writing
signed by the party against whom enforcement of the change, waiver, discharge or
termination is sought.

     12.11. Transferability.
            ---------------

            (a) No Borrower shall assign any of its rights, interests or
Obligations under this Agreement.

            (b) No Lender shall assign its interests under this Agreement to
any person or entity, without the prior written consent of both Citizens Bank
and the Borrowers; provided that (i) the Borrowers' consent shall not be
required for assignments from one Lender to another Lender or at any time during
which an Event of Default shall have occurred and be continuing; and (ii) the
Borrowers' consent shall not be unreasonably withheld or delayed. Subject to
obtaining such consent, any Lender may assign its interest, in the ordinary
course of its commercial banking business, at any time, or sell participations
in some but not all of its rights and obligations under this Agreement and the
other Loan Documents, provided that (a) the purchaser of any such interest is a
commercial bank (a "Participating Lender") or Eligible Assignee, in either case
whose total assets exceed Five Hundred Million and No/100 Dollars
($500,000,000.00); (b) at least thirty (30) days' prior written notice of such
sale or assignment, which notice must identify the Participating Lender and/or
Eligible Assignee, shall have been issued by such transferring Lender to the
Administrative Agent and the Borrowers; (c) the dollar equivalent of the
Percentage of the transferring Lender being assigned equals or exceeds Five
Million and No/100 Dollars ($5,000,000.00); (d) the Administrative Agent shall
have received a duly executed Assignment and Acceptance Agreement, in the form
attached as Exhibit 10 hereto; and (e) if the proposed assignee of the
transferring Lender is not an affiliate of the transferring Lender, an
assignment fee in the amount of Three Thousand Five Hundred and No/100 Dollars
$3,500.00) shall have been paid to the Administrative Agent to reimburse the
Administrative Agent for costs and expenses incurred in connection with the
assignment.

                                       66

<PAGE>

          12.12. Governing Law; Binding Effect. This Agreement shall be governed
                 -----------------------------
by the laws of the Commonwealth of Virginia and be binding upon each Borrower
and inure to the benefit of the parties hereto and their respective successors
and assigns.

          12.13. Gender; Number. As used herein, the singular number shall
                 --------------
include the plural, the plural the singular and the use of the masculine,
feminine or neuter gender shall include all genders, as the context may require.

          12.14. Joint and Several Liability. Each Borrower shall be jointly and
                 ---------------------------
severally liable for the payment and performance of all obligations and
liabilities hereunder.

          12.15. Materiality. Unless the context clearly indicates to the
                 -----------
contrary, determinations regarding the materiality of any act, event, condition
or circumstance shall be in the reasonable judgment of the Administrative Agent.

          12.16. Reliance on the Administrative Agent. Each Borrower shall be
                 ------------------------------------
entitled to assume that any and all consents, approvals or notices issued or
granted by the Administrative Agent pursuant to the terms and provisions of this
Agreement were, to the extent necessary, authorized by the Required Lenders or
all of the Lenders, as applicable.

          12.17. Counterparts. This Agreement may be executed in any number of
                 ------------
counterparts, all of which together shall constitute one and the same document.

                  [Remainder of Page Intentionally Left Blank]

                                       67

<PAGE>

          IN WITNESS WHEREOF, this Agreement has been signed, sealed and
delivered as of the date and year first above written.

WITNESS:
[Corporate Seal]                           MANTECH INTERNATIONAL
                                           CORPORATION, a New Jersey
                                           corporation

By:     _______________________            By:     _________________________
Name:   Hedy L.Nelson                      Name:   Matthew P. Galaski
                                           Title:  Vice President

                                           MANTECH INTERNATIONAL CORPORATION,
                                                a Delaware corporation
                                           MANTECH ADVANCED SYSTEMS
                                                INTERNATIONAL, INC., a Virginia
                                                corporation
                                           MANTECH SYSTEMS ENGINEERING
                                                CORPORATION, a Virginia
                                                corporation
                                           NSI TECHNOLOGY SERVICES CORPORATION,
                                                a California corporation
                                           MANTECH SYSTEMS CORPORATION, a New
                                                Jersey corporation
                                           MANTECH SOLUTIONS CORPORATION, a
                                                Virginia corporation
                                           MANTECH ENVIRONMENTAL TECHNOLOGY,
                                                INC., a Virginia corporation
                                           MANTECH SUPPORT TECHNOLOGY, INC.,
                                                a Virginia corporation
                                           MANTECH AUSTRALIA INTERNATIONAL,
                                                INC., a Virginia corporation
                                                formerly known as ManTech
                                                Computer Company, Inc.
                                           FIELD SUPPORT SERVICES MuHENDISLIK
                                                LIMITED SIRKETI, a corporation
                                                organized and existing under the
                                                laws of Turkey
                                           MANTECH TELECOMMUNICATIONS AND
                                                INFORMATION SYSTEMS CORPORATION,
                                                a Delaware corporation formerly
                                                known as ManTech Strategic
                                                Associates, Ltd.
WITNESS:                                   TECHNOLOGY MANAGEMENT CORPORATION, a
                                                Virginia corporation

By:     _______________________            By:      _________________________
Name:   Hedy L. Nelson                     Name:    Matthew P. Galaski
                                           Title:   Vice President

                                       68

<PAGE>
                                           SCIENCE ENGINEERING & ANALYSIS,
                                                INCORPORATED, a Virginia
                                                corporation
                                           MANTECH ENVIRONMENTAL RESEARCH
                                                SERVICES CORP., a Virginia
                                                corporation
                                           NSI ENVIRONMENTAL SOLUTIONS, INC., a
                                                Virginia corporation
                                           MANTECH ENVIRONMENTAL CORPORATION, a
                                                Virginia corporation
                                           MANTECH SYSTEMS SOLUTIONS
                                                CORPORATION, a Virginia
                                                corporation formerly known as
                                                Tidewater Consultants, Inc.
                                           MANTECH TEST SYSTEMS, INC., a
                                                Virginia corporation
                                           MANTECH SOLUTIONS & TECHNOLOGIES
                                                CORPORATION, a Virginia
                                                corporation formerly known as
                                                ManTech Systems Integration
                                                Corporation
                                           MANTECH U.K. SYSTEMS CORPORATION,
                                                a Virginia corporation
                                           REDESMUNDIAL, S.A. , a corporation
                                                organized and existing under the
                                                laws of the Republic of Panama
                                                formerly known as ManTech
                                                International Panama, Inc.
                                           MANTECH CHINA SYSTEMS CORPORATION, a
                                                Virginia corporation
                                           MANTECH GERMANY SYSTEMS CORPORATION,
                                                a Virginia corporation
                                           MANTECH ADVANCED DEVELOPMENT GROUP,
                                                INC., a California corporation
                                           MANTECH ENTERPRISE SOLUTIONS, INC.,
                                                a Virginia corporation
WITNESS:                                   VOBIX CORPORATION, a Virginia
                                                corporation
                                           MANTECH SECURITY TECHNOLOGIES
                                                CORPORATION, a Virginia
                                                corporation

By:      _______________________           By:      _________________________
Name:    Hedy L. Nelson                    Name:    Matthew P. Galaski
                                           Title:   Vice President

                                       69

<PAGE>
                                           MANTECH DATABASE SERVICES
                                                EUROPE LIMITED, a United Kingdom
                                                corporation
                                           MANTECH ADVANCED RECOGNITION
                                                LIMITED, a private company
                                                registered in England under the
                                                number 885326 formerly known as
                                                Advanced Recognition Limited
WITNESS:                                   MASI U.K. LIMITED, a corporation
                                                organized and existing under the
                                                laws of the United Kingdom

By:      _______________________           By:      _________________________
Name:    Hedy L. Nelson                    Name:    Matthew P. Galaski
                                           Title:   Attorney-in-Fact

                                             LENDER(S):
                                             ---------

                                             CITIZENS BANK OF PENNSYLVANIA, a
                                             Pennsylvania state chartered bank

                                             By:      _________________________
                                             Name:    _________________________
                                             Title:   _________________________

                                             PNC BANK, NATIONAL ASSOCIATION, a
                                             national banking association

                                             By:      _________________________
                                             Name:    _________________________
                                             Title:   _________________________

                                             BRANCH BANKING AND TRUST COMPANY
                                             OF VIRGINIA, a Virginia banking
                                             corporation

                                             By:      _________________________
                                             Name:    _________________________
                                             Title:   _________________________

                                             CHEVY CHASE BANK, F.S.B., a federal
                                             savings bank

                                             By:      _________________________
                                             Name:    _________________________
                                             Title:   _________________________

                                       70

<PAGE>
                                             ADMINISTRATIVE AGENT:
                                             --------------------

                                             CITIZENS BANK OF PENNSYLVANIA, a
                                             Pennsylvania state chartered bank

                                             By:      _________________________
                                             Name:    _________________________
                                             Title:   _________________________

                                             DOCUMENTATION AGENT:

                                             PNC BANK, NATIONAL ASSOCIATION, a
                                             national banking association

                                             By:      _________________________
                                             Name:    _________________________
                                             Title:   _________________________

                                       71

<PAGE>

                                    EXHIBIT 1
                                    ---------

                      REQUEST FOR ADVANCE AND CERTIFICATION
                        Facility A - $65,000,000 Revolver

 Citizens Bank of Pennsylvania, 8521 Leesburg Pike, Suite 405, Vienna, Virginia
                                     22182

                               REQUEST FOR ADVANCE
                               -------------------

     The undersigned, MANTECH INTERNATIONAL CORPORATION, a New Jersey
corporation ("ManTech"), for itself and as attorney-in-fact for and on behalf of
each Borrower (hereinafter defined) under that certain Business Loan and
Security Agreement dated as of December 17, 2001 (as amended or modified from
time to time, the "Loan Agreement") by and among (i) Citizens Bank of
Pennsylvania, a Pennsylvania state chartered bank, acting in its individual
capacity as a Lender, as the Swing Line Lender and as the Administrative Agent
for the Lenders, (ii) PNC Bank, National Association, a national banking
association, acting in its individual capacity as a Lender and as the
Documentation Agent for the Lenders, (iii) Branch Banking and Trust Company of
Virginia, a Virginia banking corporation, acting in its individual capacity as a
Lender, Chevy Chase Bank, F.S.B., a federal savings bank, acting in its
individual capacity as a Lender, and other Lender parties thereto from time to
time and/or replacements thereof, and (iv) ManTech, certain subsidiaries of
ManTech and any person or entity who has become a Borrower party thereto
pursuant to the Loan Agreement (collectively, the "Borrower"), hereby requests
that a Loan advance under Facility A be made to the Borrowers pursuant to
Section 1.4(a) of the Loan Agreement in the amount of
_______________________________________________________ and No/100 Dollars
($_____________.00). This Loan advance will be effective on __________________
and will be at the __ Base Rate option or the __ Libor Rate option (check one).
If the Libor Rate option is requested, it shall be effective for a ____ (select
1, 3 or 6) month period, commencing on ________________ (a Business Day not less
than two (2) Business Days nor more than five (5) Business Days from the date of
submission of this Request for Advance and Certification) and expiring on
___________ (not later than the Maturity Date). Capitalized terms used but not
defined herein shall have the meanings attributed to such terms in the Loan
Agreement.

                                  CERTIFICATION
                                  -------------

     The undersigned certifies to the Administrative Agent, on behalf of each of
the Borrowers and for the benefit of the Lenders, that (a) all of the
representations and warranties of the Borrowers contained in the Loan Agreement
are true and correct as of the date hereof, unless the Borrowers are unable to
remake and redate any such representation or warranty, have previously disclosed
the same to the Administrative Agent and the Lenders in writing, and such
inability does not constitute or give rise to an Event of Default; and (b) no
default or Event of Default exists under the Loan Agreement, and no act, event
or condition has occurred or exists which with the giving of notice or the
passage of time, or both, would constitute a default or Event of Default under
the Loan Agreement.

     IN WITNESS WHEREOF, the undersigned has executed and delivered this
certificate, this ___ day of __________, ______.

                            MANTECH INTERNATIONAL CORPORATION,
                            acting on its own behalf and as attorney-in-fact for
                            and on behalf of each Borrower

                            By:    _________________________________
                            Name:  _______________________________
                            Title:  _________________________________

<PAGE>

                                  EXHIBIT 1(a)
                                  ------------

                       REQUEST FOR SWING LINE LOAN ADVANCE

      Citizens Bank of Pennsylvania, 8521 Leesburg Pike, Suite 405, Vienna,
                                 Virginia 22182

     The undersigned, MANTECH INTERNATIONAL CORPORATION, a New Jersey
corporation ("ManTech"), for itself and as attorney-in-fact for and on behalf of
each Borrower (hereinafter defined) under that certain Business Loan and
Security Agreement dated as of December 17, 2001 (as amended or modified from
time to time, the "Loan Agreement") by and among (i) Citizens Bank of
Pennsylvania, a Pennsylvania state chartered bank, acting in its individual
capacity as a Lender, as the Swing Line Lender and as the Administrative Agent
for the Lenders, (ii) PNC Bank, National Association, a national banking
association, acting in its individual capacity as a Lender and as the
Documentation Agent for the Lenders, (iii) Branch Banking and Trust Company of
Virginia, a Virginia banking corporation, acting in its individual capacity as a
Lender, Chevy Chase Bank, F.S.B., a federal savings bank, acting in its
individual capacity as a Lender, and other Lender parties thereto from time to
time and/or replacements thereof, and (iv) ManTech, certain subsidiaries of
ManTech and any person or entity who has become a Borrower party thereto
pursuant to the Loan Agreement (collectively, the "Borrower"), hereby requests
that a Swing Line Loan advance be made to the Borrowers pursuant to Section
1.4(a) of the Loan Agreement in the amount of
______________________________________ and No/100 Dollars ($_______________).
Capitalized terms used but not defined herein shall have the meanings attributed
to such terms in the Loan Agreement.

                                  CERTIFICATION
                                  -------------

     The undersigned certifies to the Administrative Agent, on behalf of each of
the Borrowers and for the benefit of the Lenders, that (a) all of the
representations and warranties of the Borrowers contained in the Loan Agreement
are true and correct as of the date hereof, unless the Borrowers are unable to
remake and redate any such representation or warranty, have previously disclosed
the same to the Administrative Agent and the Lenders in writing, and such
inability does not constitute or give rise to an Event of Default; and (b) no
default or Event of Default exists under the Loan Agreement, and no act, event
or condition has occurred or exists which with the giving of notice or the
passage of time, or both, would constitute a default or Event of Default under
the Loan Agreement.

     IN WITNESS WHEREOF, the undersigned has executed and delivered this
certificate, this ___ day of __________, ______.

                            MANTECH INTERNATIONAL CORPORATION,
                            acting on its own behalf and as attorney-in-fact for
                            and on behalf of each Borrower

                            By:    _________________________________
                            Name:  _______________________________
                            Title:  _________________________________

                                       2

<PAGE>

                                    EXHIBIT 2
                                    ---------

                      LIBOR ELECTION FORM AND CERTIFICATION

 Citizens Bank of Pennsylvania, 8521 Leesburg Pike, Suite 405, Vienna, Virginia
                                      22182

     The undersigned, MANTECH INTERNATIONAL CORPORATION, a New Jersey
corporation ("ManTech"), for itself and as attorney-in-fact for and on behalf of
each Borrower (hereinafter defined) under that certain Business Loan and
Security Agreement dated as of December 17, 2001 (as amended or modified from
time to time, the "Loan Agreement"), by and among (i) Citizens Bank of
Pennsylvania, a Pennsylvania state chartered bank, acting in its capacity as a
Lender, as the Swing Line Lender and as Administrative Agent for the Lenders,
(ii) PNC Bank, National Association, a national banking association, acting in
its capacity as a Lender and as Documentation Agent for the Lenders, and (iii)
Branch Banking and Trust Company of Virginia, a Virginia banking corporation,
Chevy Chase Bank, F.S.B., a federal savings bank, and other Lender parties
thereto from time to time and/or replacements thereof, and (iv) ManTech, certain
subsidiaries of ManTech and any other entity who becomes a Borrower party
pursuant to the Loan Agreement (each, a "Borrower" and collectively, the
"Borrower"), hereby requests that the sum of
______________________________________________________ and No/100 Dollars
($____________________.00), advanced and outstanding under ___ Facility A / ___
Facility B (check one), bear interest on a LIBOR basis. This LIBOR basis
election shall be effective for a ____ (select 1, 3 or 6) month period,
commencing on _____________ (a Business Day not less than two (2) Business Days
nor more than five (5) Business Days from the date of submission of this LIBOR
Election Form and Certification), and expiring on _______________ (not later
than the Maturity Date). Capitalized terms used but not defined herein shall
have the meaning attributable to such terms in the Loan Agreement.

                                  CERTIFICATION
                                  -------------

     The undersigned certifies to the Administrative Agent, on behalf of each of
the Borrowers and for the benefit of the Lenders, that (a) all of the
representations and warranties of the Borrowers contained in the Loan Agreement
are true and correct as of the date hereof, unless the Borrowers are unable to
remake and redate any such representation or warranty, have previously disclosed
the same to the Administrative Agent and the Lenders in writing, and such
inability does not constitute or give rise to an Event of Default; and (b) no
default or Event of Default exists under the Loan Agreement, and no act, event
or condition has occurred or exists which with the giving of notice or the
passage of time, or both, would constitute a default or Event of Default under
the Loan Agreement.

     IN WITNESS WHEREOF, the undersigned has executed and delivered this
certificate, this ___ day of ____________, _______.

                            MANTECH INTERNATIONAL CORPORATION,
                            acting on its own behalf and as attorney-in-fact for
                            and on behalf of each Borrower

                            By:________________________________
                            Name: ____________________________
                            Title: _____________________________

<PAGE>

                                    EXHIBIT 3
                                    ---------

               LIBOR INTEREST ELECTION PROCEDURE AND REQUIREMENTS

The Borrowers' right to obtain LIBOR based interest shall be subject to the
following conditions:

     1.   Continuation and Conversion of LIBOR Elections. By delivering a LIBOR
          ----------------------------------------------
Election Form and Certification to the Administrative Agent on or before 10:00
a.m., New York time, on a Business Day, the Borrowers may from time to time
irrevocably elect, on not less than two (2) Business Days nor more than five (5)
Business Days' notice, that all, or any portion in an aggregate minimum amount
of One Hundred Thousand and No/100 Dollars ($100,000.00) and integral multiples
of One Hundred Thousand and No/100 Dollars ($100,000.00), of any LIBOR Rate Loan
be converted on the last day of an Interest Period into a LIBOR Rate Loan with a
different Interest Period, or continued on the last day of an Interest Period as
a LIBOR Rate Loan with a similar Interest Period, provided, however, that no
                                                  --------  -------
portion of the outstanding principal amount of any LIBOR Rate Loans may be
converted to, or continued as, LIBOR Rate Loans when any Event of Default has
occurred and is continuing or when any act, event or condition exists or has
occurred which with notice or the lapse of time, or both, would constitute an
Event of Default, and no portion of the outstanding principal amount of any
LIBOR Rate Loans may be converted to, LIBOR Rate Loans of a different duration
if such LIBOR Rate Loans relate to any Hedging Obligations. In the absence of
delivery of a LIBOR Election Form and Certification with respect to any LIBOR
Rate Loan at least two (2) Business Days before the last day of the then current
Interest Period with respect thereto, such LIBOR Rate Loan shall, on such last
day, automatically convert to a Loan that accrues interest on a Base Rate basis.
No more than five (5) different LIBOR funding segments may be outstanding at any
time.

     2.   Repayments, Prepayments and Interest.
          ------------------------------------

               (a)  Repayments, Continuations and Conversions. LIBOR Rate Loans
                    -----------------------------------------
shall mature and become payable in full on the last day of the Interest Period
relating to such LIBOR Rate Loan. Upon maturity, a LIBOR Rate Loan may be
continued for an additional Interest Period or may be converted to a loan that
accrues interest on a Base Rate basis.

               (b)  Voluntary Prepayment of LIBOR Rate Loans. LIBOR Rate Loans
                    ----------------------------------------
may be prepaid upon the terms and conditions set forth herein and in the Notes.
For LIBOR Rate Loans in connection with which the Borrowers have or may incur
Hedging Obligations, additional obligations may be associated with prepayment,
in accordance with the terms and conditions of the applicable Hedging Contracts.
The Borrowers shall give the Administrative Agent, no later than 10:00 a.m., New
York City time, at least four (4) Business Days notice of any proposed
prepayment of any LIBOR Rate Loans, specifying the proposed date of payment of
such LIBOR Rate Loans, and the principal amount to be paid. Each partial
prepayment of the principal amount of LIBOR Rate Loans shall be in an integral
multiple of One Hundred Thousand and No/100 Dollars ($100,000.00) and be
accompanied by the payment of all charges outstanding on such LIBOR Rate Loans
and of all accrued interest on the principal repaid to the date of payment. The
Borrowers acknowledge that prepayment or acceleration of a LIBOR Rate Loan
during an Interest Period shall result in the Administrative Agent and/or the
Lenders (as applicable) incurring additional costs, expenses and/or liabilities
and that it is extremely difficult and impractical to ascertain the extent of
such costs, expenses and/or liabilities. Therefore, all full or partial
prepayments of LIBOR Rate Loans shall be accompanied by, and the Borrowers
hereby promise to pay, on each date a LIBOR Rate Loan is prepaid or the date all
sums payable hereunder become due and payable, by acceleration or otherwise, in
addition to all other sums then owing, an amount ("LIBOR Rate Loan Prepayment
Fee") determined by the Administrative Agent pursuant to the following formula:

                    (i)    the then current rate for United States Treasury
securities (bills on a discounted basis shall be converted to a bond equivalent)
with a maturity date closest to the end of the Interest Period as to which
prepayment is made, subtracted from
                    ---------------

<PAGE>

                    (ii)   the LIBOR Lending Rate, plus the Applicable Libor
Interest Rate Margin applicable to the LIBOR Rate Loan being prepaid.

     If the result of the foregoing calculation is zero or a negative number,
then there shall be no LIBOR Rate Loan Prepayment Fee. If the result of the
foregoing calculation is a positive number, then the resulting percentage shall
be multiplied by the amount of the LIBOR Rate Loan being prepaid. This resulting
amount shall be divided by 360 and multiplied by the number of days remaining in
the Interest Period as to which the prepayment is being made. Said amount shall
be reduced to present value calculated by using the referenced United States
Treasury securities rate and the number of days remaining on the Interest Period
for the LIBOR Rate Loan being prepaid.

     The resulting amount of these calculations shall be the LIBOR Rate Loan
Prepayment Fee.

               (c)  Interest Provisions. Interest on the outstanding principal
                    -------------------
amount of each LIBOR Rate Loan shall accrue during the Interest Period
applicable thereto at a rate equal to the sum of the LIBOR Lending Rate for such
Interest Period plus the Applicable Libor Interest Rate Margin thereto and be
payable on each Interest Payment Date.

     3.   Miscellaneous LIBOR Rate Loan Terms.
          -----------------------------------

               (a)  LIBOR Rate Lending Unlawful. If the Administrative Agent
                    ---------------------------
shall determine (which determination shall, upon notice thereof to the Borrowers
be conclusive and binding on the Borrowers) that the introduction of or any
change in or in the interpretation of any law, rule, regulation or guideline,
(whether or not having the force of law) makes it unlawful, or any central bank
or other governmental authority asserts that it is unlawful, for the
Administrative Agent or any Lender to make, continue or maintain any LIBOR Rate
Loan as, or to convert any loan into, a LIBOR Rate Loan of a certain duration,
the obligations of the Administrative Agent and/or the Lenders to make,
continue, maintain or convert into any such LIBOR Rate Loans shall, upon such
determination, forthwith be suspended until the Administrative Agent shall
notify the Borrowers that the circumstances causing such suspension no longer
exist, and all LIBOR Rate Loans of such type shall automatically convert into
Loans that accrue interest on a Base Rate basis at the end of the then current
Interest Periods with respect thereto or sooner, if required by such law or
assertion.

               (b)  Substitute Rate. If the Administrative Agent shall have
                    ---------------
determined that:

                    (i)   US dollar deposits in the relevant amount and for the
relevant Interest Period are not available to the Administrative Agent and/or
the Lenders in the London interbank market; or

                    (ii)  by reason of circumstances affecting the
Administrative Agent and/or the Lenders in the London interbank, adequate means
do not exist for ascertaining the LIBOR Rate applicable hereunder to LIBOR Rate
Loans of any duration, or

                    (iii) LIBOR no longer adequately reflects the Administrative
Agent's or any Lender's cost of funding Loans,

then, upon notice from the Administrative Agent to the Borrowers, the
obligations of the Administrative Agent and the Lenders set forth in the Loan
Agreement to make or continue any Loans as, or to convert any loans into, LIBOR
Rate Loans of such duration shall forthwith be suspended until the
Administrative Agent shall notify the Borrowers that the circumstances causing
such suspension no longer exist.

               (c)  Indemnities. In addition to the LIBOR Rate Loan Prepayment
                    -----------
Fee, the Borrowers jointly and severally agree to reimburse the Administrative
Agent and the Lenders (without duplication) for any increase in the cost to the
Administrative Agent and/or the Lenders (as applicable), or reduction in the
amount of any sum receivable by the Administrative Agent and/or the Lenders (as
applicable), in respect, or as a result of:

                                       2

<PAGE>

                   (i)   any conversion or repayment or prepayment of the
principal amount of any LIBOR Rate Loans on a date other than the scheduled last
day of the Interest Period applicable thereto;

                   (ii)  any loans not being made as LIBOR Rate Loans in
accordance with the borrowing request thereof;

                   (iii) any LIBOR Rate Loans not being continued as, or
converted into, LIBOR Rate Loans in accordance with the applicable LIBOR
Election Notice and Certification thereof, or

                   (iv)  any costs associated with marking to market any Hedging
Obligations that (in the reasonable determination of the Administrative Agent)
are required to be terminated as a result of any conversion, repayment or
prepayment of the principal amount of any LIBOR Rate Loan on a date other than
the scheduled last day of the Interest Period applicable thereto;

          The Administrative Agent shall promptly notify the Borrowers in
writing of the occurrence of any such event, such notice to state, in reasonable
detail, the reasons therefor and the additional amount required fully to
compensate the Administrative Agent and/or the Lenders (as applicable) for such
increased cost or reduced amount. Such additional amounts shall be payable by
the Borrowers to the Administrative Agent for its own benefit or for the benefit
of the Lenders (as the case may be) within five (5) days of its receipt of such
notice, and such notice shall, in the absence of manifest error, be conclusive
and binding on the Borrowers. The Borrowers understand, agree and acknowledge
the following: (i) neither the Administrative Agent nor any Lender has any
obligation to purchase, sell and/or match funds in connection with the use of
LIBOR Rate as a basis for calculating the rate of interest on a LIBOR Rate Loan,
(ii) the LIBOR Rate may be used merely as a reference in determining such rate,
and (iii) the Borrowers have accepted the LIBOR Rate as a reasonable and fair
basis for calculating such rate, the LIBOR Rate Prepayment Fee, and other
funding losses incurred by the Administrative Agent and/or the Lenders (as the
case may be). The Borrowers further agree to pay the LIBOR Rate Prepayment Fee
and other funding losses, if any, whether or not the Administrative Agent and/or
the Lenders elect to purchase, sell and/or match funds.

               (d) Increased Costs. If, on or after the date hereof, the
                   ---------------
adoption of any applicable law, rule or regulation or guideline (whether or not
having the force of law), or any change therein, or any change in the
interpretation or administration thereof by any governmental authority, central
bank or comparable agency charged with the interpretation or administration
thereof, or compliance by the Administrative Agent or any Lender with any
request or directive (whether or not having the force of law) of any such
authority, central bank or comparable agency shall:

                   (i)   subject the Administrative Agent or any Lender to any
tax, duty or other charge with respect to its LIBOR Rate Loans or its obligation
to make LIBOR Rate Loans, or shall change the basis of taxation of payments to
the Administrative Agent or any Lender of the principal of or interest on its
LIBOR Rate Loans or any other amounts due under this Agreement in respect of its
LIBOR Rate Loans or its obligation to make LIBOR Rate Loans (except for the
introduction of, or change in the rate of, tax on the overall net income of the
Administrative Agent or any Lender (as applicable) or franchise taxes, imposed
by the jurisdiction (or any political subdivision or taxing authority thereof)
under the laws of which the Administrative Agent or such Lender is organized or
in which the Administrative Agent's or such Lender's principal executive office
is located); or

                   (ii)  impose, modify or deem applicable any reserve, special
deposit or similar requirement (including, without limitation, any such
requirement imposed by the Board of Governors of the Federal Reserve System of
the United States) against assets of, deposits with or for the account of, or
credit extended by, the Administrative Agent or any Lender or shall impose on
the Administrative Agent or any Lender or on the London interbank market any
other condition affecting its LIBOR Rate Loans or its obligation to make LIBOR
Rate Loans;

and the result of any of the foregoing is to increase the cost to the
Administrative Agent or such Lender of making or maintaining any LIBOR Rate
Loan, or to reduce the amount of any sum received or receivable by the
Administrative Agent or such Lender under this Agreement with respect thereto,
by an amount deemed by the

                                       3

<PAGE>

Administrative Agent to be material, then, within fifteen (15) days after demand
by the Administrative Agent, the Borrowers shall pay to the Administrative
Agent, for its own account or for the account of such Lender (as the case may
be), such additional amount or amounts as will compensate the Administrative
Agent or such Lender for such increased cost or reduction.

               (e) Increased Capital Costs. If any change in, or the
                   -----------------------
introduction, adoption, effectiveness, interpretation, reinterpretation or
phase-in of, any law or regulation, directive, guideline, decision or request
(whether or not having the force of law) of any court, central bank, regulator
or other governmental authority affects or would affect the amount of capital
required or expected to be maintained by the Administrative Agent or any Lender,
or person controlling the Administrative Agent or any Lender, and the
Administrative Agent determines (in its sole and absolute discretion) that the
rate of return on its, the Lender's or such controlling person's capital as a
consequence of its commitments or the loans made by the Administrative Agent or
such Lender is reduced to a level below that which the Administrative Agent,
such Lender or such controlling person could have achieved but for the
occurrence of any such circumstance, then, in any such case upon notice from
time to time by the Administrative Agent to the Borrowers, the Borrowers shall
immediately pay directly to the Administrative Agent, for its own account or for
the account of such Lender (as the case may be), additional amounts sufficient
to compensate the Administrative Agent, such Lender or such controlling person
for such reduction in rate of return. A statement of the Administrative Agent as
to any such additional amount or amounts (including calculations thereof in
reasonable detail) shall, in the absence of manifest error, be conclusive and
binding on the Borrowers. In determining such amount, the Administrative Agent
may use any method of averaging and attribution that it (in its sole and
absolute discretion) shall deem applicable.

               (f) Taxes. All payments by the Borrowers of principal of, and
                   -----
interest on, the LIBOR Rate Loans and all other amounts payable hereunder shall
be made free and clear of and without deduction for any present or future
income, excise, stamp or franchise taxes and other taxes, fees, duties,
withholdings or other charges of any nature whatsoever imposed by any taxing
authority, but excluding franchise taxes and taxes imposed on or measured by the
Administrative Agent's and/or any Lender's net income or receipts (such
non-excluded items being called "Taxes"). In the event that any withholding or
deduction from any payment to be made by the Borrowers hereunder is required in
respect of any Taxes pursuant to any applicable law, rule or regulation, then
the Borrowers will

                   (i)   pay directly to the relevant authority the full amount
required to be so withheld or deducted;

                   (ii)  promptly forward to the Administrative Agent an
official receipt or other documentation satisfactory to the Administrative Agent
evidencing such payment to such authority; and

                   (iii) pay to the Administrative Agent, for its own account or
for the account of such Lender (as the case may be), such additional amount or
amounts as is necessary to ensure that the net amount actually received by the
Administrative Agent, for its own account or for the account of such Lender (as
the case may be), will equal the full amount the Administrative Agent or such
Lender (as applicable) would have received had no such withholding or deduction
been required.

Moreover, if any Taxes are directly asserted against the Administrative Agent or
any Lender with respect to any payment received by the Administrative Agent or
any Lender hereunder, the Administrative Agent or such Lender may pay such Taxes
and the Borrowers will promptly pay such additional amount (including any
penalties, interest or expenses) as is necessary in order that the net amount
received by the Administrative Agent or such Lender (as the case may be) after
the payment of such Taxes (including any Taxes on such additional amount) shall
equal the amount the Administrative Agent or such Lender (as the case may be)
would have received had not such Taxes been asserted.

          If the Borrowers fail to pay any Taxes when due to the appropriate
taxing authority or fail to remit to the Administrative Agent the required
receipts or other required documentary evidence, the Borrowers shall

                                       4

<PAGE>

indemnify the Administrative Agent and the Lenders for any incremental Taxes,
interest or penalties that may become payable by the Administrative Agent or any
Lender as a result of any such failure.

                (g) Certain Required Information. If a Request for Advance and
                    ----------------------------
Certification or LIBOR Election Form and Certification fails to specify an
Applicable Interest Rate and/or an Interest Period, or if, after having selected
an Applicable Interest Rate and/or an Interest Period, the Borrowers fail or are
otherwise not entitled under the provisions of this Agreement to elect or
continue any such selection (as applicable), the Borrowers shall be deemed to
have selected the Base Rate as the Applicable Interest Rate until such time as
the Borrowers are entitled to and have selected a different Applicable Interest
Rate and specified Interest Period in accordance with the provisions of this
Agreement. The Lenders shall not be obligated to act with respect to the
provisions of this Exhibit unless the Administrative Agent shall have received a
Request for Advance and Certification or LIBOR Election Form and Certification,
as applicable, from the Borrowers specifying the following information:

                        (i)   the amount of the advance subject to the
                              Applicable Interest Rate election;

                        (ii)  the length of the Interest Period; and

                        (iii) the date on which such election is requested to be
                              effective.

Each Request for Advance and Certification or LIBOR Election Form and
Certification, as applicable, shall be made by the Borrowers in accordance with
the provisions of this Exhibit, the Notes and Section 1.4 of the Loan Agreement.

          Capitalized terms used and not otherwise defined in this Exhibit 3
shall have the meanings attributed to such terms in the Loan Agreement.

                                       5

<PAGE>

                                    EXHIBIT 4
                                    ---------

                     BORROWING BASE/NON-DEFAULT CERTIFICATE
      Citizens Bank of Pennsylvania, 8521 Leesburg Pike, Suite 405, Vienna,
                                 Virginia 22182

     Pursuant to the terms and conditions of a certain Business Loan and
Security Agreement dated as of December 17, 2001 (as amended or modified from
time to time, the "Loan Agreement") made by and among (i) Citizens Bank of
Pennsylvania, a Pennsylvania state chartered bank, acting in its individual
capacity as a Lender, as the Swing Line Lender and as Administrative Agent for
the Lenders, (ii) PNC Bank, National Association, a national banking
association, acting in its capacity as a Lender and as Documentation Agent for
the Lenders, (iii) Branch Banking and Trust Company of Virginia, a Virginia
banking corporation, Chevy Chase Bank, F.S.B., a federal savings bank, and other
Lender parties thereto from time to time and/or replacements thereof, and (iv)
ManTech International Corporation, a New Jersey corporation ("ManTech"), certain
subsidiaries of ManTech and any person or entity who has become a borrower party
thereto pursuant to the Loan Agreement (collectively, the "Borrower"), ManTech,
for itself and as attorney-in-fact for and on behalf of each Borrower, hereby
delivers this Borrowing Base/Non-Default Certificate to the Administrative Agent
to induce the Lenders to make Loan advances to the Borrower pursuant to the Loan
Agreement. Capitalized terms used but not defined herein shall have the meanings
attributed to such terms in the Loan Agreement.

Borrower:         ManTech International Corporation and its Subsidiaries
Period Ending:    __________________
Number:           __________________

The Maximum Borrowing Base is computed as follows:

<TABLE>
<S>                                                                                           <C>
1.  Value of 90% of Eligible Billed Government Accounts Receivable from Schedule A            $____________
2.  Value of 85% of Eligible Billed Commercial Accounts Receivable from Schedule B            $____________
3.  Value of 50% of Eligible Unbilled Government Accounts Receivable from Schedule C (not
    to exceed $10,000,000)                                                                    $____________
4.  The Dollar Equivalent Amount of the Value of 60% of Eligible ARL Accounts Receivable
    from Schedule D (not to exceed $1,000,000)                                                $____________
5.  The Borrowing Base (The sum of Lines 1, 2, 3 and 4)                                       $____________
6.  Facility A Commitment Amount                                                              $65,000,000**
                                                                                              -------------
7.  Facility A Loan Balance (as of the date of this Certificate)                              $____________
8.  Aggregate Amount of Swing Line Outstandings                                               $____________
9.  Aggregate Face Amount of Outstanding Letters of Credit                                    $____________
10. The Dollar Equivalent Amount (as of the date of this Certificate) of the Duty
    Deferment Bond                                                                            $____________
11. Availability (The lesser of lines 5 or 6, minus the sum of lines 7,8, 9 and 10)           $____________
</TABLE>

** Subject to reduction pursuant to Section 1.5 of the Loan Agreement.

The undersigned certifies to the Administrative Agent, on behalf of each of the
Borrowers and for the benefit of the Lenders, that (a) this report is true and
correct in all respects, is in accordance with the books and records of the
Borrowers and has been prepared in accordance with the terms of the Loan
Agreement; (b) all of the representations and warranties of the Borrowers
contained in the Loan Agreement are true and correct as of the date hereof,
unless the Borrowers are unable to remake and redate any such representation or
warranty, have previously disclosed same to the Administrative Agent

<PAGE>

and the Lenders in writing, and such inability does not constitute or give rise
to an Event of Default; and (c) except as previously disclosed to the
Administrative Agent and the Lenders in writing, no default or Event of Default
exists under the Loan Agreement, and no act, event or condition has occurred or
exists which, with the giving of notice or the passage of time or both, would
constitute a default or Event of Default under the Loan Agreement.

IN WITNESS WHEREOF, the undersigned has executed and delivered this certificate,
this _________ day of ________________, ______.

                                        MANTECH INTERNATIONAL  CORPORATION,
                                        acting on its own behalf and as
                                        attorney in-fact for and on behalf of
                                        each Borrower

                                        By: ________________________________
                                        Name: ______________________________
                                        Title: _____________________________

               {page 2 of Borrowing Base/Non-Default Certificate}

                                       2

<PAGE>

                                    EXHIBIT 5
                                    ---------

              QUARTERLY COVENANT COMPLIANCE/NON-DEFAULT CERTIFICATE
     Citizens Bank of Pennsylvania, 8521 Leesburg Pike, Suite 405, Vienna,
                                 Virginia 22182

              The undersigned, MANTECH INTERNATIONAL CORPORATION, a New Jersey
corporation ("ManTech"), for itself and as attorney-in-fact for and on behalf of
each Borrower (hereinafter defined) under that certain Business Loan and
Security Agreement dated as of December 17, 2001 (as amended or modified from
time to time, the "Loan Agreement"), by and among (i) Citizens Bank of
Pennsylvania, a Pennsylvania state chartered bank, acting in its capacity as a
Lender, as the Swing Line Lender and as Administrative Agent for the Lenders,
(ii) PNC Bank, National Association, a national banking association, acting in
its capacity as a Lender and as Documentation Agent for the Lenders, and (iii)
Branch Banking and Trust Company of Virginia, a Virginia banking corporation,
Chevy Chase Bank, F.S.B., a federal savings bank, and other Lender parties
thereto from time to time and/or replacements thereof, and (iv) ManTech, certain
subsidiaries of ManTech and any other entity who becomes a Borrower party
pursuant to the Loan Agreement (each, a "Borrower" and collectively, the
"Borrower"), hereby delivers this Quarterly Covenant Compliance/Non-Default
Certificate ("Certificate") pursuant to Section 6.3 of the Loan Agreement.
Unless otherwise defined, capitalized terms used herein shall have the meanings
attributed to such terms in the Loan Agreement.

              The undersigned, on behalf of ManTech in its individual capacity
and as attorney-in-fact for and on behalf of each Borrower, hereby certifies and
warrants that:

         (a)  He or she is the ________________ of ManTech and that, as such, he
              or she is authorized to execute this certificate on behalf of
              ManTech and each Borrower.

         (b)  At no time during the period _____________ 1, ______ through
              _____________, _______ (the "Certificate Period") did an Event of
              Default exist, and at no time during the Certificate Period did
              any act or event occur or fail to occur which with notice, or the
              lapse of time, or both, would constitute an Event of Default. [If
              unable to provide the foregoing required certification, fully
              describe the reasons therefor and circumstances thereof on a
              schedule attached hereto.]

         (c)  The following represent true and accurate measures of the
              Borrowers' financial position (on a consolidated basis) as of the
              last day of the Certificate Period:

                    (i)    Total Debt to EBITDA Ratio: ____ to 1.0.

                    (ii)   Net Worth: $_________________.

                    (iii)  Fixed Charge Coverage Ratio: _____ to 1.0.

                    (iv)   EBITDA to Interest Expense Ratio:  ______ to 1.0.

                    (v)    The Borrower's aggregate annual (i.e., fiscal year)
                           capital expenditures to date are in the amount of
                           $_________________.

                    (vi)   The aggregate amount of loans and advances to, and
                           investments in, non-Borrower subsidiaries and
                           affiliates to date is $______________.

                    (vii)  The aggregate amount of loans or advances to
                           officers of the Borrowers is $____________.

                    (viii) The aggregate outstanding principal amount of
                           borrowings by Vobix is $_______________.

<PAGE>

                       (ix) The aggregate outstanding principal amount of
                            borrowings by ARL is $_______________.

                       (x)  The Borrowers' annual (i.e., fiscal year) operating
                            lease payments to date are in the aggregate
                            amount of $_________________.

            A calculation sheet reflecting the above-computations is attached
hereto as Schedule 1.

            IN WITNESS WHEREOF, the undersigned has executed and delivered this
certificate, this ___ day of __________, ________.

                                MANTECH INTERNATIONAL CORPORATION, acting on its
                                own behalf and as attorney-in-fact for and on
                                behalf of each of the Borrowers

                                By: __________________________________
                                Name:________________________________
                                Title:_________________________________

        {page 2 of Quarterly Covenant Compliance/Non-Default Certificate}

                                       2

<PAGE>

                                    EXHIBIT 6
                                    ---------

                            FORM OF JOINDER AGREEMENT
                            -------------------------

              Re:   Business Loan and Security Agreement dated  December 17,
                    2001 (as the same may be modified or amended from time to
                    time, the "Loan Agreement") by and among (i) Citizens Bank
                    of Pennsylvania, a Pennsylvania state chartered bank, acting
                    in its individual capacity as a Lender, as the Swing Line
                    Lender and as the Administrative Agent for the Lenders, (ii)
                    PNC Bank, National Association, a national banking
                    association, acting in its individual capacity as a Lender
                    and as the Documentation Agent for the Lenders, (iii) Branch
                    Banking and Trust Company of Virginia, a Virginia banking
                    corporation, Chevy Chase Bank, F.S.B., a federal savings
                    bank and any other Lender parties thereto from time to time
                    and/or replacements thereof, and (iv) ManTech International
                    Corporation, a New Jersey corporation ("ManTech"), certain
                    subsidiaries of ManTech and any person or entity who has
                    become a borrower party thereto pursuant to the Loan
                    Agreement.

              The undersigned hereby (i) agrees to become a "Borrower" under the
Loan Agreement; (ii) joins in, becomes a party to, and agrees to comply with and
be bound by the terms and conditions of the Loan Agreement and each and every
other Loan Document, to the same extent as if the undersigned were an original
signatory thereto; (iii) makes all of the representations and warranties set
forth in the Loan Agreement and each other Loan Document to which more than one
(1) Borrower is a party thereto; and (iv) grants to the Administrative Agent,
for the ratable benefit of the Lenders, a valid and enforceable security
interest in and to all of its assets constituting Collateral, free and clear of
all liens, claims and encumbrances (other than Permitted Liens and any other
liens expressly approved in writing by the Administrative Agent) subject to the
provisions of the Loan Agreement. The undersigned shall hereafter be jointly and
severally liable for the performance of any and all past, present and future
obligations of any Borrower in connection with any of the Notes, the Loan
Agreement and/or the other Loan Documents; it being understood and agreed that
any and all references in the Notes, the Loan Agreement and/or the other Loan
Documents to "the Borrower" shall mean the undersigned, individually and/or
collectively with all other Borrowers.

              The undersigned acknowledges that (i) the Lenders have agreed to
extend credit to it and the other Borrower(s) on an integrated basis for the
purposes set forth in the Loan Agreement; (ii) it is receiving direct and/or
indirect benefits from each such extension of credit; and (iii) the obligations
of the "Borrower" or "Borrowers" under the Loan Agreement are the joint and
several obligations of each Borrower.

              The undersigned hereby represents and warrants to the
Administrative Agent and the Lenders that, in accordance with the terms of the
Contribution Agreement, it has become a party

<PAGE>

to the Contribution Agreement and that, except for the joining of the
undersigned thereto, the Contribution Agreement remains unmodified and in full
force and effect.

              The undersigned further represents and warrants to the
Administrative Agent and the Lenders that both prior to and after giving effect
to the transactions contemplated by the terms and provisions of this Joinder
Agreement, it (i) owned and owns property (including, without limitation,
contribution rights against the other Borrower(s), evidence of which, if
required by the Administrative Agent as a condition precedent to the
transactions contemplated hereby, must be in form and substance reasonably
satisfactory to the Administrative Agent) whose fair salable value is greater
than the amount required to pay all of such undersigned's Indebtedness
(including contingent debts), (ii) was and is able to pay all of its
Indebtedness as such Indebtedness matures, and (iii) had and has capital
sufficient to carry on its business and transactions and all business and
transactions in which it is about to engage. For purpose hereof, "Indebtedness"
means, without duplication (a) all items which in accordance with GAAP would be
included in determining total liabilities as shown on the liability side of a
balance sheet of the undersigned, as of the date on which Indebtedness is to be
determined, (b) all obligations of any other person or entity which the
undersigned has guaranteed, (c) reimbursement obligations in connection with
letters of credit issued for the benefit of the undersigned, and (d) the
Obligations.

              Capitalized terms used and not defined herein shall have the
meaning ascribed to such terms in the Loan Agreement.

              IN WITNESS WHEREOF, each of the undersigned has executed this
Joinder  Agreement  under seal as of the ____ day of ______________, ______.

Attest:                                     [NEW BORROWER NAME], a _____________
[Corporate Seal]

By:      _____________________________      By:      ___________________________
Name:    _____________________________      Name:    ___________________________
Title:   _____________________________      Title    ___________________________

                                       2

<PAGE>

                                   EXHIBIT 7
                                   ---------

                              FINANCIAL STATEMENTS
                              --------------------

<PAGE>

                                    EXHIBIT 8
                                    ---------

                                ESCROW AGREEMENT
                                ----------------

<PAGE>

                                    EXHIBIT 9
                                    ---------

                                 [Pricing Grid]

<TABLE>
<CAPTION>
If the Total Debt
to EBITDA Ratio is:  less than or equal to    greater than 2.0 to 1.0, but less     greater than 2.50 to 1.0, but
                           2.0 to 1.0            than or equal to 2.50 to 1.0     less than or equal to 3.25 to 1.0
<S>                  <C>                      <C>                                 <C>
then the Facility
A LIBOR Margin
shall be:                    1.75%                          2.00%                               2.25%

then the Facility
A Base Rate Margin
shall be:                    0.50%                          0.75%                               1.00%

then the Facility
A Commitment Fee
shall be:                    0.325%                         0.38%                               0.38%

then the Letter of
Credit Fee shall             1.75%                          1.75%                               1.75%
be:

then the Facility
B LIBOR Margin
shall be:                    2.25%                          2.50%                               2.75%

then the Facility
B Base Rate Margin
shall be:                    1.00%                          1.25%                               1.50%
</TABLE>

<PAGE>

                                   EXHIBIT 10
                                   ----------

                   FORM OF ASSIGNMENT AND ACCEPTANCE AGREEMENT

     THIS ASSIGNMENT AND ACCEPTANCE (this "Assignment and Acceptance") is made
this _____ day of ____________, ________, by and between
_________________________ (the "Assignor") and ________________________ (the
"Assignee"). Reference is made to the Business Loan and Security Agreement,
dated as of December 17, 2001 (as the same may be amended or modified from time
to time, the "Loan Agreement"), by and among (i) Citizens Bank of Pennsylvania,
a Pennsylvania state chartered bank, acting in its individual capacity as a
Lender, as the Swing Line Lender and as the Administrative Agent for the
Lenders, (ii) PNC Bank, National Association, a national banking association,
acting in its individual capacity as a Lender and as the Documentation Agent for
the Lenders, (iii) Branch Banking and Trust Company of Virginia, a Virginia
banking corporation, Chevy Chase Bank, F.S.B., a federal savings bank and any
other Lender parties thereto from time to time and/or replacements thereof, and
(iv) ManTech International Corporation, a New Jersey corporation ("ManTech"),
certain subsidiaries of ManTech and any person or entity who has become a
borrower party thereto pursuant to the Loan Agreement (collectively, the
"Borrowers"). Unless otherwise defined herein, capitalized terms used herein
without definition shall have the meanings given to them in the Loan Agreement.

     The Assignor and the Assignee hereby agree as follows:

     4. Assignment and Assumption. Subject to the terms and conditions hereof,
        -------------------------
the Assignor hereby sells and assigns to the Assignee, and the Assignee hereby
purchases and assumes from the Assignor, without recourse to the Assignor and,
except as expressly provided herein, without representation or warranty by the
Assignor, the interest or interests as of the Effective Date (as hereinafter
defined) in and to all of the Assignor's rights and obligations under the Loan
Agreement and the other Loan Documents (in its capacity as a Lender thereunder)
with respect to each of the Facilities represented by the Percentage(s)
specified with regard to such Facilities under the heading "Assigned Share" in
Item 4 of Annex I (each such assigned interest, an "Assigned Share"), including,
------    -------
without limitation, (i) in the case of the Loans made pursuant to Facility B,
the relevant Assigned Share of all rights and obligations of the Assignor with
respect to its "Commitments" under Facility B (unless terminated), Facility B
Promissory Note(s), and the Loans outstanding under Facility B (as the case may
be), and (ii) in the case of Loans made pursuant to Facility A, the relevant
Assigned Share of all rights and obligations of the Assignor with respect to its
Percentage of the Facility A Commitment Amount, Letter(s) of Credit, Swing Line
Loan Facility, Facility A Promissory Note(s) and Loans outstanding under
Facility A (as applicable). For purposes hereof, the "Commitments" shall mean,
individually or collectively as the context may require, the Facility A
Commitment Amount and/or the Facility "B" Commitment Amount.

     5. The Assignor. The Assignor (i) represents and warrants that it is the
        ------------
legal and beneficial owner of each interest being assigned by it hereunder, that
each such interest is free and clear of any adverse claim, and that as of the
date hereof its Commitments and outstanding Loans of each of the Facilities with
regard to which an interest is being assigned hereunder

<PAGE>

(including any obligations with respect to Letter(s) of Credit, if applicable)
is as set forth in Item 4 of Annex I, (ii) except as set forth in clause (i)
                   ------    -------
above, makes no representation or warranty and assumes no responsibility with
respect to any statements, warranties or representations made in or in
connection with the Loan Agreement, any other Loan Document or any other
instrument or document furnished pursuant thereto or the execution, legality,
validity, enforceability, genuineness, sufficiency or value of the Loan
Agreement, any other Loan Document or any other instrument or document furnished
pursuant thereto, and (iii) makes no representation or warranty and assumes no
responsibility with respect to the financial condition of the Borrowers or the
performance or observance by the Borrowers of any of their respective
obligations under the Loan Agreement, any other Loan Document or any other
instrument or document furnished pursuant thereto.

     6. The Assignee. The Assignee (i) represents and warrants that it is
        ------------
legally authorized to enter into this Assignment and Acceptance, (ii) confirms
that it has received a copy of the Loan Agreement, together with copies of the
financial statements most recently required to have been delivered under Section
6.3 of the Loan Agreement and such other documents and information as it has
deemed appropriate to make its own credit analysis and decision to enter into
this Assignment and Acceptance, (iii) agrees that it will, independently and
without reliance upon any Agent, the Assignor or any other Lender, and based on
such documents and information as it shall deem appropriate at the time,
continue to make its own credit decisions in taking or not taking action under
the Loan Agreement, (iv) confirms that it is an Eligible Assignee, (v) appoints
and authorizes the Administrative Agent to take such actions as agent on its
behalf under the Loan Agreement and the other Loan Documents, and to exercise
such powers and to perform such duties, as are specifically delegated to the
Administrative Agent by the terms thereof, together with such other powers and
duties as are reasonably incidental thereto, and (vi) agrees that it will
perform in accordance with their respective terms all of the obligations that by
the terms of the Loan Agreement are required to be performed by it as a Lender.
[To the extent legally entitled to do so, the Assignee will deliver to the
Agent, as and when required by the Administrative Agent, duly completed and
executed originals of any and all applicable tax withholding forms]./1/

     7. Effective Date. Following the execution of this Assignment and
        --------------
Acceptance by the Assignor and the Assignee, an executed original hereof,
together with all attachments hereto, shall be delivered to each of the
Administrative Agent and the Borrowers (and also to the Administrative Agent,
the assignment fee referred to in Section 12.11(b) of the Loan Agreement, if
applicable). The effective date of this Assignment and Acceptance (the
"Effective Date") shall be the earlier of (i) the date of acceptance hereof by
the Administrative Agent and the Borrowers or (ii) the date, if any, designated
as the Effective Date in Item 5 of Annex I (which date shall be not less than
                         ------    -------
five (5) Business Days after the date of execution hereof by the Assignor and
the Assignee). As of the Effective Date, (y) the Assignee shall be a party to
the Loan Agreement and, to the extent provided in this Assignment and
Acceptance, shall have the rights and obligations of a Lender thereunder and
under the other Loan Documents, and (z) the Assignor

_______________
     /1/ Insert if the Assignee is organized under the laws of a jurisdiction
outside the United States.

                                       2

<PAGE>

shall, to the extent provided in this Assignment and Acceptance, relinquish its
rights (other than rights under the provisions of the Loan Agreement and the
other Loan Documents relating to indemnification or payment of fees, costs and
expenses, to the extent such rights relate to the time prior to the Effective
Date) and be released from its obligations under the Loan Agreement and the
other Loan Documents.

     8.  Payments; Settlement. On or prior to the Effective Date, in
         --------------------
consideration of the sale and assignment provided for herein and as a condition
to the effectiveness of this Assignment and Acceptance, the Assignee will pay to
the Assignor an amount (to be confirmed between the Assignor and the Assignee)
that represents the Assigned Share of the principal amount of the Loans of each
relevant Facility made by the Assignor and outstanding on the Effective Date
(together, if and to the extent the Assignor and the Assignee so elect, with the
Assigned Share of any related accrued but unpaid interest, fees and other
amounts). From and after the Effective Date, the Administrative Agent will make
all payments required to be made by it under the Loan Agreement in respect of
each interest assigned hereunder (including, without limitation, all payments of
principal, interest and fees in respect of the Assigned Share of the Assignor's
Commitments and Loans assigned hereunder) directly to the Assignee. The Assignor
and the Assignee shall be responsible for making between themselves all
appropriate adjustments in payments due under the Loan Agreement in respect of
the period prior to the Effective Date. All payments required to be made
hereunder or in connection herewith shall be made in Dollars by wire transfer of
immediately available funds to the appropriate party at its address for payments
designated in Annex I.
              -------

     9.  Governing Law. This Assignment and Acceptance shall be governed by, and
         -------------
construed in accordance with, the internal laws of the Commonwealth of Virginia
(without regard to the conflicts of laws principles thereof).

     10. Entire Credit Agreement. This Assignment and Acceptance, together with
         -----------------------
the Loan Agreement and the other Loan Documents, embody the entire agreement and
understanding between the parties hereto and (except as otherwise expressly set
forth in the Loan Agreement) supersede all prior agreements and understandings
of the parties, verbal or written, relating to the subject matter hereof.

     11. Successors and Assigns. This Assignment and Acceptance shall be binding
         ----------------------
upon, inure to the benefit of and be enforceable by the parties hereto and their
respective successors and assigns.

     12. Counterparts. This Assignment and Acceptance may be executed in any
         ------------
number of counterparts and by different parties hereto on separate counterparts,
each of which, when so executed and delivered shall be an original, but all of
which shall together constitute one and the same instrument.

     IN WITNESS WHEREOF, the parties have caused this Assignment and Acceptance
to be executed by their duly authorized officers as of the date first above
written.

                                    ASSIGNOR:

                                       3

<PAGE>

                                          ___________________________________
                                          By: ______________________________
                                          Title: __________________________

                                          ASSIGNEE:

                                          ___________________________________
                                          By: ______________________________
                                          Title: __________________________

Accepted this ____ day of
________________, _____:

CITIZENS BANK OF PENNSYLVANIA, as Administrative Agent

By: ________________________________
Title: _______________________________

Consented and agreed to (if applicable):

MANTECH INTERNATIONAL CORPORATION,
acting on its own behalf and as attorney-in-fact
for and on behalf of each Borrower

By: ________________________________
Title: _______________________________

                                       4

<PAGE>

                                     ANNEX I
                                     -------

1.   Borrowers: ManTech International Corporation and its Subsidiaries

2.   Name and Date of Loan Agreement:

     Business Loan and Security Agreement, dated as of December 17, 2001, by and
     among (i) Citizens Bank of Pennsylvania, a Pennsylvania state chartered
     bank, acting in its individual capacity as a Lender, as the Swing Line
     Lender and as the Administrative Agent for the Lenders, (ii) PNC Bank,
     National Association, a national banking association, acting in its
     individual capacity as a Lender and as the Documentation Agent for the
     Lenders, (iii) Branch Banking and Trust Company of Virginia, a Virginia
     banking corporation, Chevy Chase Bank, F.S.B., a federal savings bank and
     any other Lender parties thereto from time to time and/or replacements
     thereof, and (iv) ManTech International Corporation, a New Jersey
     corporation ("ManTech"), certain subsidiaries of ManTech and any person or
     entity who has become a borrower party thereto pursuant to the Loan
     Agreement (collectively, the "Borrowers")

3.   Date of Assignment and Acceptance: ________________, ______.

4.   Amounts:

<TABLE>
<CAPTION>
                                                             Amount of           Aggregate
                               Aggregate      Assigned       Assigned          for Assignor
                              for Assignor    Share/2/         Share        (after assignment)
                              ------------    -------          -----        ------------------
<S>                           <C>             <C>            <C>            <C>
(a) Facility A Commitment
    Amount                    $__________      _____%        $________          $___________
(b) Facility A Loans          $__________      _____%        $________          $___________
(c) Facility B Commitment
    Amount                    $__________      _____%        $________          $___________
(d) Facility B Loans          $__________      _____%        $________          $___________
</TABLE>

5.   Effective Date: _____________, _______.

____________
/2/ Percentage taken to up to ten decimal places, if necessary.

<PAGE>

6.   Addresses for Payments:

     Assignor:      _________________________________
                    _________________________________
                    _________________________________
                    Attention: __________________
                    Telephone: __________________
                    Telecopy: ___________________
                    Reference: __________________

     Assignee:      _________________________________
                    _________________________________
                    _________________________________
                    Attention: __________________
                    Telephone: __________________
                    Telecopy: ___________________
                    Reference: __________________

7.   Addresses for Notices:

     Assignor:      _________________________________
                    _________________________________
                    _________________________________
                    Attention: __________________
                    Telephone: __________________
                    Telecopy: ___________________

     Assignee:      _________________________________
                    _________________________________
                    _________________________________
                    Attention: __________________
                    Telephone: __________________
                    Telecopy: ___________________

8.   Lending Office of Assignee:
     _________________________________
     _________________________________
     _________________________________
     Attention: __________________
     Telephone: __________________
     Telecopy: ___________________

                                       2

<PAGE>

                                   EXHIBIT 11
                                   ----------

                      FIRST SOURCE SUBDEBT LETTER AGREEMENT
                      -------------------------------------

<PAGE>

                                   SCHEDULE 1
                                   ----------

<TABLE>
<CAPTION>
                                  Facility A                   Facility B              Swing Line Facility
     Lenders              Percentage /Commitment $     Percentage /Commitment $     Percentage /Commitment $
     -------              ------------------------     ------------------------     ------------------------
<S>                       <C>          <C>             <C>           <C>            <C>         <C>
Citizens Bank               37.5%      $24,375,000        37.5%      $2,400,000       100%      $10,000,000
PNC                          25%       $16,250,000         25%       $1,600,000        0%            $0
BB&T                      19.257703%   $12,517,507      19.257703%   $1,232,493        0%            $0
Chevy Chase               18.2422969%  $11,857,493     18.2422969%   $1,167,507        0%            $0

TOTALS:                      100%      $65,000,000         100%      $6,400,000       100%      $10,000,000
</TABLE>

Wiring Instructions:   Citizens Bank of Pennsylvania
                       Philadelphia, PA
                       ABA #031 000 037
                       Attn:  Loan Administration
                       Account #9908 73703
                       Ref: ManTech International Corporation
                       PAYDOWN/ADVANCE/ETC.
                       Attn: Jeff Gillard

Wiring Instructions:   PNC Bank, National Association
                       ABA # 031207607
                       For Credit to PNC Business Credit
                       Account # 196039957830
                       For the benefit of ManTech International Corporation
                       Attn: Paul Raquepo

Wiring Instructions:   Branch Banking and Trust Company of Virginia
                       1909 K Street, N.W.
                       Washington, D.C. 2006
                       ABA # 054001547
                       Ref: ManTech International Loan
                       Account # 9560118500
                       Notify: Denise Wright at 202-835-9208

Wiring Instructions:   Chevy Chase Bank, F.S.B.
                       ABA# 255071981
                       Attention: CLS
                       Account # 29050030 r/c 082
                       Ref: ManTech
                       Attention: Rick Buterbaugh

<PAGE>
                                  SCHEDULE 4.3
                                  ------------

1.    FIELD SUPPORT SERVICES MUHENDISLIK LIMITED SIRKETI, a corporation
      organized and existing under the laws of Turkey;

2.    MASI U.K. LIMITED, a corporation organized and existing under the laws of
      the united kingdom;

3.    MANTECH ADVANCED RECOGNITION LIMITED, a private company registered in
      England under the number 885326 formerly known as Advanced Recognition
      Limited;

4.    MANTECH DATABASE SERVICES EUROPE LIMITED, a corporation organized and
      existing under the laws of the United Kingdom; and

5.    REDESMUNDIAL, S.A., a corporation organized and existing under the laws of
      the Republic of Panama formerly known as ManTech International Panama,
      Inc.<PAGE>
                                                                    Exhibit 10.5

                                 PROMISSORY NOTE
                                 ---------------

$100,000.00
13 April 2001
--
Fairfax, Virginia

FOR VALUE RECEIVED, the undersigned George J. Pedersen (the "Maker") an
individual having an address at 700 Potomac Knolls Drive, McLean, VA 22101,
promises to pay to the order of ManTech International Corporation (the
"Holder"), the sum of One Hundred Thousand Dollars ($100,000.00) together with
interest at the rate of Eight Percent (8%) per year in equal monthly
installments of $667.67 commencing on May 11, 2001 and continuing on the same
day of each succeeding month thereafter until paid in full.

This Note may be prepaid at any time or from time to time in whole or in part
without penalty, premium or permission.

In the event of any default hereof, all remaining payments shall become due and
payable at the option of the Holder and the Maker agrees to pay all costs of
collection, including reasonable attorneys' fees if placed in the hands of an
attorney for collection. Upon default, the Maker further authorizes any Clerk of
any Court of Record in the Commonwealth of Virginia or elsewhere to enter
judgment by confession against them in favor of the Holder hereof for the full
amount appearing due and payable hereon, together with interest, charges,
reasonable attorneys' fees and costs of suit, as above provided. Demand or
presentment for payment, notice of dishonor, protest and notice of protest are
hereby waived.

In the event any one or more of the provisions contained in this Note shall for
any reason be held to be invalid, illegal or unenforceable in any respect, such
invalidity, illegality or unenforceability shall not affect any other provision
of this Note, but this Note shall be construed as if such invalid, illegal or
unenforceable provision had never been contained herein.

This Note may not be changed orally but only by an agreement in writing and
signed by the paities against whom enforcement of any waiver, change,
modification or discharge is sought

This Note shall be interpreted in accordance with the laws of the Commonwealth
of Virginia.

MAKER:

/s/ George J. Pedersen
-----------------------------
George J. Pedersen

WITNESS/ATTEST:

/s/ J. Jaye Free
------------------------------
J. Jaye Free

<PAGE>
                                                                    Exhibit 10.5

                                 PROMISSORY NOTE
                                 ---------------

$16,795.93                                                       June 12, 1996

     FOR VALUE RECEIVED, George J. Pedersen, 700 Potomac Knolls Drive, McLean,
VA 22101, promises to pay to order of ManTech International Corporation on
demand as the holder of this note or at such other place as the holder of this
note might from time to time designate in writing, the principal sum of Sixteen
Thousand Seven Hundred Ninety Five Dollars and 93/100 ($16,795.93), plus
interest on the principal balance. Interest at the rate of eight (8) percent
will be calculated on an annual basis and deducted from Pedersen paycheck each
pay period. At present ManTech's systems provides for 26 paychecks per year. The
interest rate may be adjusted from time to time by Phoenix Home Life Mutual
Insurance Company and Pedersen note will be adjusted accordingly.

     1. This note may be fully or partially prepaid at any time without penalty.

     2. If the undersigned defaults in the payment of any installment due under
this note and fails to cure such default within thirty (30) days after the
holder of this note has sent written notice of default, then, at the option of
the holder of this note, the entire principal balance of this note and all
accrued and unpaid interest shall at once become due. Failure to exercise this
option shall not constitute a waiver of the right to exercise the same in the
event of any subsequent default.

     3. The undersigned promises to pay all costs of collection, including
reasonable attorney's fees, upon default in the payment of the principal or
interest of this note when due, whether suit is brought or not.

     4. In the event any one or more of the provisions contained in this note is
held to be invalid, illegal or unenforceable for any reason, such invalidity,
illegality or unenforceability is not to affect any other provision of the note;
this note is to be construed as if such invalid, illegal or unenforceable
provision had never been a part of it.

     5. This note may not be changed orally but only by an agreement in writing
and signed by the party against whom agreement enforcement of any change is
sought.

     6. The note is to be interpreted in accordance with the laws of the
Commonwealth of Virginia.

ATTEST                                  NAME
/s/ J. Jaye Free                        /s/ George J. Pedersen
------------------------------          ---------------------------
                                        George J. Pedersen
                                        Chairman of the Board

<PAGE>
                                                                    Exhibit 10.5
FROM CORPORATE OFFICE

                                 PROMISSORY NOTE
                                 ---------------

$52,360.00                                                        23 June 1994

     FOR VALUE RECEIVED, George J. Pedersen, 700 Potomac Knolls Drive, McLean,
VA 22101, promises to pay to the order of ManTech International Corporation on
demand as the holder of this note or at such other place as the holder of this
note might from time to time designate in writing, the principal sum of Fifty
Two Thousand Three Hundred Sixty Dollars ($52,360.00), plus interest due on the
principal balance. Interest at the rate of eight (8) percent will be calculated
on an annual basis and deducted from Pedersen paycheck each pay period. At
present ManTech's systems provides for 26 paychecks per year. The interest rate
may be adjusted from time to time by Phoenix Home Life Mutual Insurance Company
and Pedersen note will be adjusted accordingly.

          1. This note may be fully or partially prepaid at any time without
penalty.

          2. If the undersigned defaults in the payment of any installment due
under this note and fails to cure such default within thirty (30) days after the
holder of this note has sent written notice of default, then, at the option of
the holder of this note, the entire principal balance of this note and all
accrued and unpaid interest shall at once become due. Failure to exercise this
option shall not constitute a waiver of the right to exercise the same in the
event of any subsequent default.

          3. The undersigned promises to pay all costs of collection, including
reasonable attorney's fees, upon default in the payment of the principal or
interest of this note when due, whether suit is brought or not.

          4. In the event any one or more of the provisions contained in this
note is held to be invalid, illegal or unenforceable for any reason, such
invalidity, illegality or unenforceability is not to affect any other provision
of the note; this note is to be construed as if such invalid, illegal or
unenforceable provision had never been a part of it.

          5. This note may not be changed orally but only by an agreement in
writing and signed by the party against whom agreement enforcement of any change
is sought.

          6. This note is to be interpreted in accordance with the laws of the
Commonwealth of Virginia.

                                       /s/ George J. Pedersen
                                       ---------------------------
                                       George J. Pedersen
                                       Chairman of the Board

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