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                                                                   EXHIBIT 10.30

                         SECOND MODIFICATION AGREEMENT

       THIS SECOND MODIFICATION AGREEMENT (this "Agreement"), effective as of
the ____________ day of ___________ 2000, is by and among UNITED BANK, a
Virginia banking corporation (the "Bank"); HADRON, INC., a New York corporation,
AVENUE TECHNOLOGIES, INC., a Virginia corporation, VAIL RESEARCH AND TECHNOLOGY
CORPORATION, a Virginia corporation, SYCOM SERVICES, INC., a Delaware
corporation, and ENGINEERING & INFORMATION SERVICES, INC., a Virginia
corporation (hereinafter individually and collectively called the "Borrower");
C.W. GILLULY, in his capacity as junior creditor under the Subordination
Agreement referred to in this Agreement (the "Junior Creditor") and JON M. STOUT
(the "Remaining Guarantor").

                                 WITNESSETH THAT:

       WHEREAS, the Bank is the owner and holder of (i) that certain Revolving
Commercial Note dated June 29, 1999, made by the Borrower and payable to the
order of the Bank, in the original principal amount of One Million Five Hundred
Thousand and no/100 Dollars ($1,500,000.00) and bearing interest and being
payable in accordance with the terms and conditions therein set forth, and (ii)
that certain Commercial Note dated June 29, 1999, made by the Borrower and
payable to the order of the Bank, in the original principal amount of One
Million Five Hundred Thousand and no/100 Dollars ($1,500,000.00) and bearing
interest and being payable in accordance with the terms and conditions therein
set forth (collectively, the "Notes"); and

       WHEREAS, the Notes are secured by, and issued pursuant to the terms of, a
certain Loan and Security Agreement dated June 29, 1999, between the Borrower
and the Bank (as amended by a certain First Modification and Extension Agreement
dated as of April 12, 2000, the "Loan Agreement"); and

       WHEREAS, as of the effective date hereof, the aggregate principal balance
of the Notes is $________________ and the parties hereto desire to increase the
amount guaranteed by the Remaining Guarantor, release the Released Guarantors
(defined below) from all liability as such and to modify the terms of the Loan
Agreement accordingly.

       NOW, THEREFORE, for Ten Dollars ($10.00) and other good and valuable
consideration, the receipt and sufficiency of which are hereby acknowledged, the
parties hereto agree as follows:

       1.   C.W. Gilluly and Martha Alice Gilluly (the "Released Guarantors")
are hereby released from all liability as guarantors of the payment of the Notes
and the other obligations of the Borrower under the Loan Agreement, and their
Amended and Restated Guaranty of Payment dated April 12, 2000 in favor of the
Bank is hereby canceled.  The obligations of the Junior Creditor, also one of
the Released Guarantors, under that certain Subordination Agreement dated April
12, 2000, with the Bank and Hadron, Inc., remain unchanged and said
Subordination Agreement is hereby expressly approved, ratified and confirmed.

       2.   The obligation of the Remaining Guarantor under his Guaranty of
Payment dated April 12, 2000 is hereby increased in accordance with that certain
Amended and Restated Guaranty of
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Payment of even date herewith from the Remaining Guarantor in favor of the Bank
(the "Amended Guaranty"). Contemporaneously with the execution and delivery of
this Agreement, the Remaining Guarantor shall execute and deliver to the Bank
the Amended Guaranty on the Bank's form therefor.

       3.   The Loan Agreement is hereby amended to the extent necessary to
carry out the purposes of this Agreement..

       4.   The Borrower and the Remaining Guarantor hereby acknowledge and
agree that, as of the effective date hereof, the aggregate unpaid principal
balance of the Notes is $________________ and that there are no set-offs or
defenses against the Note or the Loan Agreement.

       5.   The Remaining Guarantor joins in this Agreement for the additional
purpose of signifying his consent hereto and acknowledges and agrees that there
are no set-offs or defenses against his guaranty (as increased pursuant to
paragraph 2 of this Agreement and that his guaranty of the Notes (as increased
as aforesaid) shall apply to the Notes notwithstanding the release of the
Released Guarantors.

       6.   The parties to this Agreement do not intend that this Agreement be
construed as a novation of the Notes or the Loan Agreement.

       7.   Except as hereby expressly extended and modified, the Loan Agreement
shall otherwise be unchanged, shall remain in full force and effect, and is
hereby expressly approved, ratified and confirmed.

       8.   This Agreement shall be governed in all respects by the laws of the
Commonwealth of Virginia and shall be binding upon and shall inure to the
benefit of the parties hereto and their respective heirs, executors,
administrators, personal representatives, successors and assigns.

WITNESS the following signatures and seals.

                              HADRON, INC.                   [SEAL]



                              By: ____________________________________
                                    Name:
                                    Title:

                                      -2-
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                              AVENUE TECHNOLOGIES, INC.      [SEAL]



                              By: ____________________________________
                                    Name:
                                    Title:


                              VAIL RESEARCH AND TECHNOLOGY CORPORATION
                              [SEAL]


                              By: ____________________________________
                                    Name:
                                    Title:


                              SYCOM SERVICES, INC.           [SEAL]



                              By: ____________________________________
                                    Name:
                                    Title:


                              ENGINEERING & INFORMATION SERVICES, INC.



                              By: ____________________________________
                                    Name:
                                    Title:



                              __________________________________  [SEAL]
                              C.W. GILLULY (in his capacity as junior creditor
                              pursuant to the aforementioned Subordination
                              Agreement only)

                                      -3-
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                              __________________________________  [SEAL]
                              JON M. STOUT


                              UNITED BANK                         [SEAL]



                              By: ____________________________________
                                    Name:
                                    Title:

                                      -4-