ATK Spacecraft Bus Contributes to Significant ORS-1 Milestone

ORS-1 Satellite Completes Successful On-Orbit Checkout

U.S. Air Force Declares Spacecraft Fully Operational

ATK (NYSE: ATK) joins the U.S. Air Force in marking a significant milestone for the Department of Defense’s Operationally Responsive Space-1 (ORS-1) satellite. The space vehicle was declared fully operational on Friday, September 16th, 2011 by the U.S. Air Force Space Command at Schriever Air Force Base, Colorado following successful on-orbit deployment and checkout of all systems.

Launched June 29, 2011 from the Mid-Atlantic Regional Spaceport at NASA Wallops Flight Facility, Wallops Island, Virginia, the ORS-1 is the first satellite in the DoD’s Operationally Responsive Space program designed to support combatant command operations as an operational satellite. The ORS-1 mission focuses on the quick deployment of a small satellite with innovative sensor technologies to provide real-time support to commanders in the battlefield.

ATK’s spacecraft bus met the ORS program goals of being operationally responsive with affordable technology and unprecedented rapid execution from design to launch. ATK built the bus in just 16 months at its Beltsville, Maryland facility and shipped it ahead of schedule to Goodrich Corporation, the prime contractor for the ORS-1 satellite.

“As the spacecraft bus provider and one of the systems integration partners on the ORS-1 team, ATK is proud to be part of this transformational achievement in the growing market for affordable small satellites supporting warfighter needs,” said Tom Wilson, vice president and general manager of the Spacecraft Systems & Services division of the ATK Aerospace Systems group. “We are proud to have delivered mission success for all of our customers with a 100% success rate in orbit. ATK’s ability to build a proven satellite bus in record time at low cost provides our military and other users with unprecedented flexibility to put missions of their choosing into flight operations. We look forward to using our flight-proven hardware with a wide variety of sensor technologies in future missions.” The satellite bus is based on the design ATK developed for the successful TacSat-3 satellite (an earlier demonstration program) with the addition of a propulsion module. TacSat-3 launched in 2009, transitioned to full operation in October 2010, and continues to support warfighters in the battlefield.

A Minotaur rocket boosted ORS-1 into orbit, for which ATK also manufactured the Stage 3 Orion 50XL and the Stage 4 Orion 38 rocket motors. ATK’s Clearfield, Utah facility provided the composite 2/3 interstage and associated raceways while ATK’s San Diego, California facility provided the ORS-1 payload’s telescope structure under subcontract to Goodrich. Working closely with Goodrich, the team accomplished a challenging schedule of hardware delivery within eight months.

The ORS-1 program is managed and executed by the Space Development & Test Directorate, SMC/SD at Kirtland Air Force Base. SMC/SD is executing the program for the ORS Office, which is a joint initiative of several agencies within the DoD responsible for integrating joint ORS capabilities and applying ORS resources to the development, acquisition and demonstration of capabilities to meet specific responsive space needs as established by global combatant command joint force commanders. ATK is an aerospace, defense, and commercial products company with operations in 22 states, Puerto Rico, and internationally, with revenues of approximately $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 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.