ATK Builds on Recent Success with Two More Critical Design Tests for the U.S. Navy’s Extended Range Munition Program

ATK’S BTERM Rocket Motor Achieves Full Burn After Gun-Launch

ATK Ignition Safety Device Delivers First for Guided Projectiles

Minneapolis, April 25, 2006 – Alliant Techsystems (NYSE: ATK) announced today that it has successfully fired a Ballistic Trajectory Extended Range Munition (BTERM) rocket motor in support of the U.S. Navy’s Extended Range Munition (ERM) program. Following the successful validation test of its rocket motor, ATK demonstrated the effectiveness of its Ignition Safety Device (ISD). Both tests were conducted at the Yuma Proving Grounds, Yuma, Ariz., on April 14, 2006.

The first test was a boosted, unguided shot of ATK’s rocket motor design. After exiting the barrel, the rocket motor ignited and achieved a complete burn. “We are confident that the BTERM rocket motor and ATK’s demonstrated guidance capability will provide the U.S. Navy and Marine Corps with a highly accurate, long-range precision projectile,” said Jack Cronin, President, ATK Mission Systems. ATK is now preparing for its next phase in the development plan, a series of boosted and guided flight tests.

In a separate flight test, ATK demonstrated the capability of its unique ISD design. As intended, the ISD ignited the rocket motor four seconds after exiting the gun. The ISD is critical to the round’s range performance across the entire set of range requirements, which extends from 15 nautical miles to 55 nautical miles.

In February this year, ATK conducted a successful guided, unboosted short-range test that demonstrated the effectiveness of its low cost guidance electronics unit (LCGEU) and its innovative single axis control actuation system. “The recent series of guided and unguided tests clearly establishes ATK as a leader in the development of robust and affordable solutions for gun-launched precision projectiles,” concluded Cronin.

ATK is a $3.3 billion advanced weapon and space systems company employing approximately 15,000 people in 23 states. 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 those factors are: the challenges of developing advanced precision projectiles, changes in governmental spending, budgetary policies and product sourcing strategies; the company’s competitive environment; the terms and timing of awards and contracts; and economic conditions. ATK undertakes no obligation to update any forward-looking statements. For further information on factors that could impact ATK, and statements contained herein, reference should be made to ATK’s filings with the Securities and Exchange Commission, including quarterly reports on Form 10-Q, current reports on Form 8-K, and ATK’s Annual Report on Form 10-K for the fiscal year ended March 31, 2005.

Contact Information

Bryce Hallowell

ATK Corporate Communications

Alliant Techsystems

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