EX-8.1

We are acting as tax counsel to Orbital ATK, Inc., a Delaware corporation (the “Company”), and each of the subsidiary guarantors identified on Exhibit A attached hereto (each, a “Subsidiary Guarantor” and collectively, the “Subsidiary Guarantors”) in connection with the registration statement on Form S-4, as amended (the “Registration Statement”), filed with the Securities and Exchange Commission under the Securities Act of 1933, as amended (the “Act”) relating to the proposed public offering of up to $300,000,000 in aggregate principal amount of the 5.25% Senior Notes due 2021 of the Company (the “Exchange Notes”) in exchange for up to $300,000,000 in aggregate principal amount of the 5.25% Senior Notes due 2021 of the Company outstanding as of the date hereof (the “Original Notes”), and the guarantees of the Exchange Notes to be issued by the Guarantors. The Original Notes were issued, and the Exchange Notes will be issued, pursuant to an Indenture (the “Indenture”) dated as of November 1, 2013, by and among the Company, the Subsidiary Guarantors, and The Bank of New York Mellon Trust Company, N.A., as trustee. In connection with the filing of the Registration Statement, we have been asked to provide you with this letter with respect to the discussion included in the Registration Statement under the heading “Certain U.S. Federal Income Tax Considerations.” Capitalized terms used in this letter and not otherwise defined herein shall have the meanings set forth in the Registration Statement.

The opinion set forth in this letter is based on relevant current provisions of the Internal Revenue Code of 1986, as amended (the “Code”), Treasury Regulations thereunder (including proposed and temporary Treasury Regulations), and interpretations of the foregoing as expressed in court decisions, applicable legislative history, and the administrative rulings and practices of the Internal Revenue Service (the “IRS”), including its practices and policies in issuing private letter rulings, which are not binding on the IRS except with respect to a taxpayer that receives such a ruling, all as of the date hereof. These provisions and interpretations are subject to change by the IRS, Congress and the courts (as applicable), which may or may not be retroactive in effect and which might result in material modifications of our opinion. Our opinion does not foreclose the possibility of a contrary determination by the IRS or a court of competent jurisdiction, or of a contrary position taken by the IRS or the Treasury Department in regulations or rulings issued in the future. In this regard, an opinion of counsel with respect to an issue represents counsel’s best professional judgment with respect to the outcome on the merits with respect to such issue, if such issue were to be litigated, but an opinion is not binding on the IRS or the courts, and is not a guarantee that the IRS will not assert a contrary position with respect to such issue or that a court will not sustain such a position asserted by the IRS.

In rendering this opinion, we have examined such statutes, regulations, records, agreements, certificates and other documents as we have considered necessary or appropriate as a basis for the opinion, including (but not limited to) the following: (i) an executed copy of the Registration Statement; (ii) specimen copies of the Original Notes and the Exchange Notes; and (iii) an executed copy of the Indenture (together, these documents referred to in clauses (i) through (iii), the “Reviewed Documents”).

Any material variation or difference in the facts from those set forth in the documents that we have reviewed and upon which we have relied may adversely affect the conclusions stated herein. For purposes of rendering our opinion, we have not made an independent investigation of the facts set forth in the Reviewed Documents. We have consequently relied upon representations and information presented in such documents.

Based upon and subject to the assumptions and qualifications set forth herein, we are of the opinion that the portions of the discussion in the Prospectus under the heading “Certain U.S. Federal Income Tax Considerations” that describe provisions of applicable U.S. federal income tax law are correct in all material respects as of the date hereof.

Other than as expressly stated above, we express no opinion on any issue relating to the Company or to any investment therein. In particular, we express no opinion on the Company’s qualification as a real estate investment trust under the Code, the qualification of any entities in which the Company has invested as partnerships for U.S. federal income tax purposes, or any other tax consequences that may apply to the Company or to an investment in the Company’s common stock.

This opinion letter addresses only the specific U.S. federal income tax matters set forth above and does not address any other U.S. federal, state, local or foreign legal or tax issues.

This opinion letter has been prepared for your use in connection with the filing of the Registration Statement, and speaks as of the date hereof. We assume no obligation by reason of this opinion letter or otherwise to advise you of any changes in our opinion subsequent to the effective date of the Registration Statement. Except as provided in the last paragraph, this opinion letter may not be distributed, quoted in whole or in part or otherwise reproduced in any document, or filed with any governmental agency without our express written consent.

We hereby consent to the filing of this opinion letter as Exhibit 8.1 to the Registration Statement and to the reference to Hogan Lovells US LLP under the caption “Legal Matters” in the Prospectus. In giving this consent, however, we do not admit thereby that we are an “expert” within the meaning of the Act.

Very truly yours,

/s/ Hogan Lovells US LLP

HOGAN LOVELLS US LLP