SECOND AMENDED AND RESTATED CONTINUING AND Unconditional Guaranty

Exhibit 10.3

Date: April 1, 2005

Second Amended and Restated Continuing and Unconditional Guaranty

THIS SECOND AMENDED AND RESTATED CONTINUING AND UNCONDITIONAL GUARANTY (this “Agreement”) is made as of the 1st day of April, 2005, by undersigned “Guarantor”, jointly and severally, for the benefit of BANK OF AMERICA, N.A., a national banking association (“Lender”).

RECITALS

A. Analex Corporation (“Borrower”), a corporation organized under the laws of the State of Delaware, formerly known as Hadron, Inc., obtained from Lender a Revolving Credit Facility in the original maximum principal sum of $4,000,000 and a term loan in the original principal sum of $3,500,000 (the “Original Credit Facility”). Advances and readvances under the Original Credit Facility were at one time governed by the terms and conditions of that certain Credit Agreement by and among Borrower, certain subsidiaries of Borrower named therein, and Lender dated November 2, 2001 (the same, as amended, modified, substituted, extended, and renewed from time to time, the “Original Credit Agreement”).

B. Borrower and Lender entered into that certain Amended and Restated Credit Agreement dated as of May 28, 2004 which is being modified pursuant to that certain First Amendment to Amended and Restated Credit Agreement (the “First Amendment”) dated of even date herewith (the same, collectively, as amended, modified, substituted, extended, and renewed from time to time, the “Credit Agreement”) The Credit Agreement provides for some of the agreements between Borrower and Lender with respect to the “Loan” (as defined in the Credit Agreement), including Revolving Credit Facility Loans in an aggregate amount not to exceed Twenty Million Dollars ($20,000,000) (the “Revolving Credit Facility Committed Amount”).

C. The Loan is evidenced by that certain Amended and Restated Revolving Credit Facility Note dated May 28, 2004 by Borrower for the benefit of Lender in the original maximum principal amount of Twenty Million Dollars ($20,000,000) which is being amended pursuant to that certain First Amendment to Amended and Restated Revolving Credit Facility

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Note dated of even date herewith (the same, collectively, as amended, modified, substituted, extended, and renewed from time to time, the “Note”).

D. Borrower has requested and Lender has agreed to increase the Revolving Credit Facility Committed Amount from Twenty Million Dollars ($20,000,000) to Forty Million Dollars ($40,000,000) at any time outstanding, and to extend the Revolving Credit Facility Maturity Date.

E. Borrower’s obligations under the Original Credit Facility were guaranteed by the Guarantors, as defined therein, pursuant to the terms of the Continuing and Unconditional Guaranty dated November 2, 2001, as amended and restated by that certain Amended and Restated Continuing and Unconditional Guaranty dated May 28, 2004 (as amended, modified, restated, substituted, extended as renewed at any time and from time to time, the “Original Guaranty”).

F. Advanced Biosystems, Inc. (“ABI”), a Delaware corporation and one of the Guarantors pursuant to the Original Guaranty, has been sold by Borrower with the consent of Lender and has been released by Lender from all obligations it may have under the Loan Documents, including the Original Guaranty.

G. It is a condition precedent, among others, to Lender’s agreement to enter into the First Amendment and to amend the loan and other financial accommodations under the Credit Agreement, that Guarantor enter into this Agreement to amend and restate in its entirety the Original Guaranty in order to secure the full and prompt performance of Borrower of all the Obligations under all of the Loan Documents. All capitalized terms used herein and not otherwise defined shall have the meaning given to such terms in the Credit Agreement.

NOW, THEREFORE, in order to induce Lender to increase the credit facilities to the Borrower, each Guarantor hereby amends and restates the Original Guaranty and reconfirms its guaranty as follows:

1. Guaranty . FOR VALUE RECEIVED, and to induce Lender to make loans or advances or to extend credit or other financial accommodations or benefits, with or without security, to or for the account of Borrower, the undersigned “Guarantor”, if more than one, then each of them jointly and severally, hereby irrevocably and unconditionally guarantees to Lender the full and prompt payment when due, whether by acceleration or otherwise, of any and all Liabilities (as hereinafter defined) of Borrower to Lender.

The undertakings of Guarantor hereunder are independent of the Liabilities and Obligations of Borrower and a separate action or actions for payment, damages or performance may be brought or prosecuted against Guarantor, whether or not an action is brought against Borrower or to realize upon the security for the Liabilities and/or Obligations, whether or not Borrower is joined in any such action or actions, and whether or not notice is given or demand is made upon Borrower.

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Lender shall not be required to proceed against Borrower, or any other person, or entity, whether primarily or secondarily liable, or against any collateral held by it, before resorting to Guarantor for payment.

This Guaranty is continuing and unlimited as to amount, and is cumulative to and does not supersede any other guaranties. This is the Guaranty described in the Credit Agreement.

2. Paragraph Headings, Governing Law and Binding Effect . Guarantor agrees that paragraph headings in this Guaranty are for convenience only and that they will not limit any of the provisions of this Guaranty. Guarantor further agrees that this Guaranty shall be governed by and construed in accordance with the laws of the Commonwealth of Virginia and applicable United States federal law. Guarantor further agrees that this Guaranty shall be deemed to have been made in the Commonwealth of Virginia at Lender’s address indicated above, and shall be governed by, and construed in accordance with, the laws of the Commonwealth of Virginia, or the United States courts located within the Commonwealth of Virginia, and is performable in the Commonwealth of Virginia. This Guaranty is binding upon Guarantor, his, their or its executors, administrators, successors or assigns, and shall inure to the benefit of Lender, its successors, endorsees or assigns. Anyone executing this Guaranty shall be bound by the terms hereof without regard to execution by anyone else.

3. Definitions .

A. “Credit Agreement” shall mean that certain Amended and Restated Credit Agreement dated as of May 28, 2004, as amended by that certain First Amendment to Amended and Restated Credit Agreement dated of even date herewith, by and among Borrower, the Subsidiary Guarantors from time to time party thereto and Lender, and all other agreements and instruments extending, renewing, refinancing or refunding any indebtedness, obligation or liability arising under the same, as the same may be amended, modified or supplemented from time to time hereafter.

B. “Guarantor” shall mean Guarantor or any one or more of them.

C. “Liability” or “Liabilities” shall mean without limitation, all liabilities, overdrafts, indebtedness, and obligations of Borrower and/or Guarantor to Lender under the Credit Agreement and the other Loan Documents, and all sums payable under or by virtue thereof, including without limitation, all amounts of principal and interest, all expenses (including reasonable attorney’s fees and cost of collection) incurred in the collection thereof or the enforcement of rights thereunder (including, without limitation, any liability arising from failure to comply with state or federal laws, rules and regulations concerning the control of hazardous waste or substances at or with respect to any real estate securing any loan guaranteed hereby), whether arising in the ordinary course of business or otherwise. The term “Liability” or “Liabilities” shall include all Obligations (as that term is defined in the Credit Agreement). If Borrower is a partnership, corporation or other entity the term “Liability” or “Liabilities” as used herein shall include all Liabilities to Lender of any successor entity or entities.

D. “Loan Documents” shall have the meaning ascribed to such term in the Credit Agreement.

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E. “Obligation” or “Obligations” shall mean all terms, conditions, covenants, agreements and undertakings of Borrower and/or Guarantor under the Credit Agreement and the other Loan Documents.

4. Waivers by Guarantor . Guarantor waives notice of acceptance of this Guaranty, notice of any Liabilities or Obligations to which it may apply, presentment, demand for payment, protest, notice of dishonor or nonpayment of any Liabilities, notice of intent to accelerate, notice of acceleration, and notice of any suit or the taking of other action by Lender against Borrower, Guarantor or any other person, any applicable statute of limitations and any other notice to any party liable on any Loan Document (including Guarantor).

Until such time as the Liabilities have been paid in full, all Commitments under the Credit Agreement have been terminated and no Person or Governmental Authority shall have any right to request any return or reimbursement of funds from the Lender in connection with monies received under the Loan Documents, each Guarantor also hereby waives any claim, right or remedy which such Guarantor may now have or hereafter acquire against Borrower that arises hereunder and/or from the performance by any other Guarantor hereunder including, without limitation, any claim, remedy or right of subrogation, reimbursement, exoneration, contribution, indemnification, or participation in any claim, right or remedy of Lender against Borrower or against any security which Lender now has or hereafter acquires, whether or not such claim, right or remedy arises in equity, under contract, by statute, under common law or otherwise.

Guarantor also waives the benefits of any provision of law requiring that Lender exhaust any right or remedy, or take any action, against Borrower, any Guarantor, any other person and/or property, including but not limited to the provisions of Sections 49-25 and 49-26 of the Code of Virginia (1950), as amended, or otherwise.

Lender may at any time and from time to time (whether before or after revocation or termination of this Guaranty) without notice to Guarantor (except as required by law), without incurring responsibility to Guarantor, without impairing, releasing or otherwise affecting the obligations of Guarantor hereunder, in whole or in part, and without the endorsement or execution by Guarantor of any additional consent, waiver or guaranty: (a) change the manner, place or terms of payment, or change or extend the time of or renew, or change any interest rate or alter any Liability or Obligation or installment thereof, or any security therefor; (b) loan additional monies or extend additional credit to Borrower, with or without security, thereby creating new Liabilities or Obligations the payment or performance of which shall be guaranteed hereunder, and the Guaranty herein made shall apply to the Liabilities and Obligations as so changed, extended, surrendered, realized upon or otherwise altered; (c) sell, exchange, release, surrender, realize upon or otherwise deal with