RS-25 Engine Test Continues SLS Progress

A team of engineers successfully conducted a development test of the RS-25 rocket engine Thursday, Aug. 18 at NASA’s Stennis Space Center. Image Credit: NASA

A team of engineers successfully conducted a development test of the RS-25 rocket engine Thursday, Aug. 18 at NASA’s Stennis Space Center. Image Credit: NASA

August 19, 2016 – NASA engineers successfully conducted a development test of the RS-25 rocket engine Thursday, August 18 at NASA’s Stennis Space Center near Bay St. Louis, Mississippi. The RS-25 will help power the core stage of the agency’s new Space Launch System (SLS) rocket for the journey to Mars.

RS-25 engines are upgraded versions of the main engines used to power 135 space shuttle missions from 1981 to 2011. The engines were built for NASA by Aerojet Rocketdyne and are among the most proven in the world, having logged more than 1 million seconds of hot fire time during ground tests and missions. In addition to the upgraded space shuttle main engines, NASA has also contracted with Aerojet Rocketdyne to produce new RS-25 engines for use on SLS missions.

For the SLS, the engines will operate at unprecedented levels. Due to the size and nature of the SLS, the RS-25 engines must withstand colder liquid oxygen and engine compartment temperatures, higher propellant pressure and greater exhaust nozzle heating. Four RS-25 engines will fire simultaneously to provide 2 million pounds of thrust and operate in conjunction with a pair of solid rocket boosters to power the SLS at launch.

All RS-25 developmental and flight engine tests are conducted on the A-1 Test Stand at Stennis. The development tests at Stennis are providing key data on engine performance. The tests also are collecting data on the performance of a new engine controller unit, which controls internal engine functions during operation and enables proper communication between the SLS and the engine.

A variety of NASA officials and contractor representatives, as well as social and traditional media members, gathered to watch yesterday’s 420-second test of RS-25 engine No. 0528.

During the test, the engine was run through a range of varying conditions and operating parameters. For instance, operators used an extended low-flow chill down process for the engine prior to the test and also experimented with a high-pressure start process. A special engine controller wiring configuration was tested, and the engine was fired at ranges of 80 to 111 percent power during the test. Test data on engine and controller performance was provided by the facility team at twice the normal rate.

The test was conducted by a team of NASA, Aerojet Rocketdyne and Syncom Space Services personnel. Aerojet Rocketdyne is NASA’s prime contractor for developing and building RS-25 engines. Syncom Space Services is the agency’s prime contractor for maintenance of Stennis facilities and operations.

This latest test marks the third in a six-test developmental series which began with a July 14 firing and a second test on July 29. Future tests are scheduled for this fall and also will focus on gathering performance data on the engine and its new controller.

In March, NASA also began testing RS-25 engine No. 2059 for use as a flight engine on the second integrated test flight of SLS with the agency’s Orion spacecraft, known as Exploration Mission-2 (EM-2). EM-2 will carry a crew aboard the space capsule for the first time.

Future plans call for installing the SLS core stage onto the modified B-2 Test Stand at Stennis and firing its four RS-25 engines simultaneously, just as during an actual launch.