ATK, DARPA and ONR Achieve First-ever Flight Test of a Scramjet Powered by Liquid Hydrocarbon Fuel

ATK-designed Scramjet Flies in Excess of Mach 5 in a Missile Configuration

ATK Again Demonstrates its Global Leadership in Hypersonic Flight

Minneapolis, December 15, 2005 – Alliant Techsystems (NYSE: ATK), the Defense Advanced Research Projects Agency (DARPA) and the Office of Naval Research (ONR) successfully ground-launched and flew a hypersonic scramjet-powered vehicle from the Wallops Flight Facility, Wallops Island, Va. in a pre-dawn launch on Saturday, Dec. 10. This was the first-ever free flight of a scramjet-powered vehicle using conventional liquid hydrocarbon jet fuel. The launch and flight test were part of the Freeflight Atmospheric Scramjet Test Technique (FASTT) program sponsored by DARPA and ONR.

As the system integrator, ATK designed and built the FASTT vehicle. This was the first time the company had complete design authority over the hypersonic scramjet propulsion system and the airframe. In addition, ATK served as the mission manager for both the launch and the flight of the test vehicle, including development of test plans and coordination of all design and mission readiness reviews.

ATK previously built the hydrogen-fueled X-43A Scramjet, the world-record holder for powered flight which obtained a top speed of nearly Mach 10 in a November 2004 flight test. “The successful FASTT flight test and ATK’s record-setting X-43A flight tests clearly position ATK as a world-leader in the development and test of hypersonic propulsion systems and airframes,” said Blake Larson, President ATK Advanced Propulsion and Space Systems. “One goal of ATK’s hypersonic flight program is to develop advanced hypersonic weaponry and this flight test is a significant step in that direction,” said Larson

The FASTT vehicle was approximately 106 inches long and 11 inches in diameter. It integrated a Scramjet engine into a missile configuration. After separating from its booster rocket at more than 60,000 feet, the Scramjet engine ignited and propelled the vehicle at approximately 5,300 feet per second – or Mach 5.5. Using JP-10 fuel, the Scramjet flew for at least 15 seconds while critical engineering data was captured via on-board sensors and tracking radars. The vehicle continued in stable flight mode until it splashed down in the Atlantic Ocean.

The ground-launched flight test demonstrated a viable and cost-effective flight-test method for future hypersonic Scramjet initiatives.

In addition to the FASTT program, ATK’s Boost-to-Cruise initiative is developing hypersonic missile technologies capable of sustained flight at Mach 5 and delivering payloads on target more than 600 nautical miles down range.

ATK is a $3.1 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 hypersonic flight aircraft, 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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