Solar Probe Plus is scheduled to launch in 2018 on an Atlas V rocket. ATK's STAR 48GXV motor is based on the venerable STAR 48BV rocket, with roots dating back to the late 1970s and hundreds of successful Delta II-class missions. The new STAR 48GXV motor incorporates many new technologies, including lightweight composite case and exit cone materials, and advanced thrust vector controls.

"This test highlights ATK's ability to design, develop and manufacture highly engineered products to support a wide range of customer needs," said Cary Ralston, vice president and general manager, Missile Products division. "The STAR 48GXV ushers in a new performance standard for solid-propellant upper stage motors."

With its high-strength graphite composite case, the STAR 48GXV motor can operate at approximately three times the chamber pressure of its predecessor. The filament-wound case significantly reduces the cost and lead time associated with thin-walled titanium cases. The ignition train incorporates a consumable Vespel® igniter initiated by a high voltage initiator. The exit cone, manufactured at ATK's facility in Promontory, Utah, is a lightweight carbon-carbon structure that eliminates the need for support structures. ATK's thrust vector electronic control system (TVECSTM), which includes electro mechanical actuators and a digital controller, is used to command the vectorable nozzle to achieve the desired thrust vector.

The STAR 48GXV motor test, conducted at ATK's facility in Elkton, Md., provided key subsystem performance data for the final design, development and qualification effort to support the Solar Probe Plus mission. The Solar Probe Plus spacecraft, which will fly through the sun's outer atmosphere (called the corona) several times to gather data on the processes that heat the corona and accelerate the solar wind, is being developed at the Johns Hopkins Applied Physics Laboratory in Laurel, Md. Solar Probe Plus is part of NASA's Living with a Star program, managed by NASA's Goddard Space Flight Center in Greenbelt, Md., for the Science Mission Directorate at NASA Headquarters, Washington.

ATK is an aerospace, defense, and commercial products company with operations in 22 states, Puerto Rico, and internationally. News and information can be found on the Internet at www.atk.com, on Facebook at www.facebook.com/atk, or on Twitter @ATK.

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 inherent in the development of new technologies; 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.

SOURCE ATK