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Satnews Daily
April 2nd, 2009

It's All In The ATK Attitude Control


Alliant Techsystems , NASA, and industry partners Lockheed Martin Corporation and Orbital Sciences Corporation have successfully performed a ground test firing of a sub-scale attitude control motor thruster system for the launch abort system (LAS) of NASA's Orion crew exploration vehicle (CEV).

The test was conducted at ATK's facility in Elkton, Maryland. This milestone in the development of the Orion spacecraft brings the Constellation program another step closer to flight-ready status, while demonstrating its commitment to improved flight safety for astronauts. This demonstration, High Thrust-8 (HT-8), was the fifth in a series of ground tests of Orion's attitude control motor system and provided validation that several flight-weight subsystems are performing as designed. The final tests will be of increasing complexity in preparation for the Pad Abort-1 Flight Test, which will test the launch abort system's capabilities using a full-scale crew module mockup. Orion's attitude control motor will provide steering for the launch abort system. In combination with the abort motor under development by ATK, it is designed to safely lift and steer the Orion crew module away from the launch vehicle, pulling the crew to safety in the event of an emergency on the launch pad or during the initial ascent phase. The attitude control motor consists of a solid propellant gas generator, with eight proportional valves/nozzles equally spaced around the circumference of the 3 foot diameter motor. In combination, the valves can exert up to 7,000 pounds of steering force to the vehicle in any direction upon command from the crew module. The valves are controlled by a redundant power and control system. This test demonstrated one of the flight-weight valves at full thrust and at maximum stressing load.

ATK is responsible for the attitude control motor through a contract to Orbital Sciences Corporation, who is responsible for delivering the LAS motors for Lockheed Martin — NASA's prime contractor for Orion. The Orion Project is managed out of NASA's Johnson Space Center. The launch abort system is managed out of NASA's Langley Research Center in partnership with NASA's Marshall Space Flight Center.

(Video of motor thruster system test firing courtesy of ATK)