Press Release

Aerojet Rocketdyne Successfully Completes First Hot-Fire Test With RS-25 Engine Controller Unit

By SpaceRef Editor
January 12, 2015
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Aerojet Rocketdyne, a GenCorp (NYSE:GY) company, successfully completed the first in a series of hot-fire tests on the RS-25 rocket engine, which will help power NASA’s new Space Launch System (SLS) and carry humans farther into space than ever before. The test, conducted in the A-1 facility at NASA’s Stennis Space Center in Mississippi, demonstrated the ability of the engine’s new computer to control the engine – from fuel-mixture ratios to power levels and performance.

“This was an amazing first step toward our ability to send humans into deep space aboard America’s next heavy-lift rocket,” said Julie Van Kleeck, vice president of Advanced Space and Launch Programs. “We put the engine and its test facility to the task, demonstrating their ability to function properly under various conditions, and both performed very well. We look forward to watching the RS-25 engines propel astronauts on their next journey to explore deep space for the benefit of all.”

The RS-25 engine, formerly known as the Space Shuttle Main Engine (SSME), is the most reliable and highly tested human-rated rocket engine in the world, having successfully powered the space shuttle fleet during its 30-year history.

The controller on the SSME served as the “brain” and was manufactured in the 1980s, allowing for communication between the vehicle and the engine. The new computer has since been modernized with the latest technologies to provide the capability necessary for four RS-25 engines to power the SLS core stage. During the first hot-fire test at Stennis, NASA and Aerojet Rocketdyne engineers tested the upgraded engine controller unit’s ability to control the engine, using different power levels and inlet conditions.

Aerojet Rocketdyne is a world-recognized aerospace and defense leader providing propulsion and energetics to the space, missile defense and strategic systems, tactical systems and armaments areas, in support of domestic and international markets. GenCorp is a diversified company that provides innovative solutions that create value for its customers in the aerospace and defense, and real estate markets. Additional information about Aerojet Rocketdyne and GenCorp can be obtained by visiting the companies’ websites at and

SpaceRef staff editor.