Exhibit 99.1

For Immediate Release

ATK Reports FY11 Third-Quarter Operating Results

ATK On-Track to Achieve Full-Year Sales and EPS Guidance

Minneapolis, February 3, 2011 — ATK (NYSE: ATK) today reported operating results for the third quarter of its Fiscal Year 2011, which ended on January 2, 2011.  Third quarter sales of $1.1 billion remained relatively flat with the prior-year quarter, benefitting from strong sales in the Armament Systems group and Security and Sporting group (up eight percent and 25 percent, respectively), and offset by results in the Aerospace Systems group and Missile Products group.

Fully diluted earnings per share (EPS) decreased from $2.33 in the prior-year quarter to $2.09 in the current quarter.  The results reflect a $25 million ($15 million net of taxes, or $0.45 per share) reduction in sales and profit associated with a commercial aerospace structures program, partially offset by the retroactive extension of the Federal research and development (R&D) tax credit, and a continued focus on cost management and efficiency improvement initiatives company-wide.

Third quarter EPS benefitted by $0.11 from a lower tax rate due to the retroactive extension of the R&D tax credit ($0.09 of which pertained to prior quarters), and strong operating margins.  In the quarter, ATK achieved margins of 11.2 percent despite the reduction in profit from the company’s commercial aerospace structures business.  ATK is reaffirming its full-year sales and EPS guidance.

“Our lean manufacturing and cost management initiatives are taking hold across the company, yielding margin improvement to offset program level challenges and deliver solid EPS. While we reduced our profit expectations on a commercial aerospace program, our overall results on orders, sales, profit and cash supported our full-year guidance,” said Mark DeYoung, President and CEO. “We are focused on a disciplined business model that delivers shareholder value.”

SUMMARY OF REPORTED RESULTS

The following table presents the company’s results for the third quarter of the fiscal year which ended January 2, 2011 (in thousands).

Sales:

Income before Interest, Income Taxes, and Noncontrolling Interest (Operating Profit):

SEGMENT RESULTS

ATK operates in four business groups: Aerospace Systems; Armament Systems; Missile Products; and Security and Sporting.

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AEROSPACE SYSTEMS

Third quarter sales in the Aerospace Systems group declined by 17 percent from $385 million in the prior-year period to $321 million this quarter, reflecting lower sales on the Space Shuttle’s Reusable Solid Rocket Motor program due to the completion of the program, and lower sales on the Ares I program.

Earnings before interest, taxes, and noncontrolling interest (operating profit) in the third quarter declined 47 percent from $45 million in the prior-year quarter to $24 million in the current quarter, primarily reflecting the reduced sales volume as noted above, and the impact of the profit reductions in the commercial aerospace structures business.

ARMAMENT SYSTEMS

Third quarter sales in the Armament Systems group increased eight percent from $398 million in the prior-year quarter to $431 million in the current quarter.  The increase was driven by small-caliber ammunition, medium-caliber gun systems, and non-standard weapon sales, partially offset by lower sales of medium-caliber ammunition and lower modernization funding.

Operating profit in the third quarter rose 42 percent from $39 million in the prior-year quarter to $55 million in the current quarter, primarily reflecting higher sales volume, improved operating efficiencies, and the absence of costs last year associated with the construction of an energetics facility for the Australian Ministry of Defense.

MISSILE PRODUCTS

Third quarter sales in the Missile Products group were down 12 percent from $191 in the prior-year quarter to $168 million in the current quarter, reflecting lower sales on NASA’s launch abort system and special mission aircraft.

Operating profit increased 12 percent from $17 million in the prior-year quarter to $19 million in the current quarter, reflecting the benefits of efficiency improvements, and the absence of miscellaneous charges that were recorded in the prior-year quarter.

SECURITY AND SPORTING

Third quarter sales in the Security and Sporting group grew 25 percent from $167 million in the prior-year quarter to $209 million in the current quarter, reflecting increased commercial

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ammunition and tactical equipment sales, including $21 million of new sales from the recently acquired BLACKHAWK! business.

Operating profit in the third quarter increased 12 percent from $27 million in the prior-year quarter to $30 million in the current quarter, primarily reflecting higher sales volume including higher margin products from BLACKHAWK!, and improved operating efficiencies, partially offset by higher raw material costs and softening demand in some areas of commercial ammunition.

CORPORATE AND OTHER

Corporate and other expenses increased from income of $7.7 million in the prior-year quarter to an expense of $2.3 million in the current quarter.  The increase was primarily the result of higher pension expense.  The tax rate for the quarter decreased from 33.9 percent in the prior-year, to 30.7 percent, which is primarily the result of the retroactive extension of the Federal R&D tax credit.

OUTLOOK

Based on year-to-date performance, ATK continues to expect full-year EPS of $8.90 - $9.10, and full-year sales of $4.775 - $4.85 billion.

ATK continues to expect full-year interest expense of $88 million.  The company is lowering its expectations on the full-year tax rate to approximately 29 percent, from previous expectations of approximately 30 percent.  Pension expense is still expected to be approximately $130 million.  Average share count is expected to be approximately 34 million. The company continues to expect to generate free cash flow in a range of $275 - $300 million, with capital expenditures of approximately $120 million (see reconciliation table for details).

Reconciliation of Non-GAAP Financial Measures

Free Cash Flow

Free cash flow is defined as cash provided by (used for) operating activities less capital expenditures.  ATK management believes free cash flow provides investors with an important perspective on the cash

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available for debt repayment, share repurchase, and acquisitions after making the capital investments required to support ongoing business operations.  ATK management uses free cash flow internally to assess both business performance and overall liquidity.

ATK is an aerospace, defense, and commercial products company with operations in 24 states, Puerto Rico and internationally, and revenues in excess of $4.8 billion.  News and information can be found on the Internet at www.atk.com.

Certain information discussed in this press release constitutes forward-looking statements as defined in the Private Securities Litigation Reform Act of 1995.  Although ATK believes that the expectations reflected in such forward-looking statements are based on reasonable assumptions, it can give no assurance that its expectations will be achieved. Forward-looking information is subject to certain risks, trends, and uncertainties that could cause actual results to differ materially from those projected. Among these factors are: assumptions related to the profitability of current commercial aerospace structures programs; the challenges of developing new launch vehicles and the uncertainty regarding the Administration’s next-generation heavy lift vehicle architecture; changes in governmental spending, budgetary policies and product sourcing strategies; the company’s competitive environment; risks inherent in the development and manufacture of advanced technology; risks associated with the diversification into new markets; increases in commodity costs, energy prices, and production costs; the terms and timing of awards and contracts; program performance; program terminations; changes in cost estimates related to relocation of facilities; the outcome of contingencies, including litigation and environmental remediation; actual pension asset returns and assumptions regarding future returns, discount rates and service costs; capital market volatility and corresponding assumptions related to the company’s shares outstanding; the availability of capital market financing; changes to accounting standards; changes in tax rules or pronouncements; economic conditions; and the

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company’s capital deployment strategy, including debt repayment, dividend payments, share repurchases, pension funding, mergers and acquisitions and any integration thereof. ATK undertakes no obligation to update any forward-looking statements. For further information on factors that could impact ATK, and statements contained herein, please refer to ATK’s most recent Annual Report on Form 10-K and any subsequent quarterly reports on Form 10-Q and current reports on Form 8-K filed with the U.S. Securities and Exchange Commission.

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ALLIANT TECHSYSTEMS INC.

CONDENSED CONSOLIDATED INCOME STATEMENTS

(unaudited)

ALLIANT TECHSYSTEMS INC.

CONDENSED CONSOLIDATED BALANCE SHEETS

(unaudited)

ALLIANT TECHSYSTEMS INC.

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS

(unaudited)