Alliant Techsystems (NYSE: ATK) provided mission critical hardware and launch technology for NASA’s STS- 115 mission aboard the Space Shuttle Atlantis. During the launch on Saturday, ATK reusable solid rocket motors provided more than six million pounds of thrust in the first two minutes of flight to help send the Space Shuttle Atlantis mission to the International Space Station.

During the mission the STS-115 crew will install the P3/P4 integrated truss and a second set of solar arrays on the space station, doubling the station’s current ability to generate power from sunlight and adding 17.5 tons to its mass. This mission marks the first time in almost four years that a component has been added to the International Space Station.

ATK designed and fabricated the truss structures to deploy the powerful 32-kilowatt solar arrays. ATK’s Folding Articulated Square Truss (FAST) Mast technology allows for a compact stowage length less than eight feet when fully retracted and more than 115 ft long when fully deployed. The FAST Mast canister is designed to fully retract and deploy the solar arrays 35 times during its expected 15-year on-orbit life. Two FAST Masts deployed the first pair of ISS solar arrays during the STS-113 mission.

ATK’s gear driven pair of patented 10.5 ft-diameter race rings connected by 12 evenly spaced trundles will enable the Solar Alpha Rotary Joint (SARJ), built by Lockheed Martin, to function as a structural bearing joint and allow for continuous rotation of the outboard truss structure to maintain optimum positioning of the solar arrays to the Sun; maximizing the solar power provided to the ISS. ATK designed the components to withstand temperature gradients approaching 100 degrees Fahrenheit.

STS-115 is the 116th shuttle flight and the 19th U.S. flight to the International Space Station. ATK solid rocket motors have flown on each Space Shuttle mission since the inception of the program in 1981, and today are the only human-rated solid rocket motors produced in the U.S.

ATK is a $3.4 billion advanced weapon and space systems company employing approximately 15,000 people in 22 states. News and information can be found on the Internet at http://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: 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, 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.