New Launch Vehicle Engine Actually Has A Lot Of Time In Space

Formerly known as the space shuttle main engine, the RS-25 accumulated over 1 million seconds (that’s about 280 hours) of hot fire experience during 135 missions and numerous related engine tests.

The RS-25 engine that will power NASA's new rocket, the Space Launch System (SLS), off the launch pad and on journeys to an asteroid and Mars is getting ready for the test stand. And it is packing a big punch.

Engineers at NASA's Stennis Space Center near Bay St. Louis, MS, are now focusing their attention on preparing the RS-25 engine after completing testing of the J-2X engine April 10. Four RS-25 engines, previously known as space shuttle main engines, will muscle the core stage of SLS for each of its missions. Towering more than 200 feet tall with a diameter of 27.6 feet, the core stage will store cryogenic liquid hydrogen and liquid oxygen that will feed the vehicle’s RS-25s.

Modifications to the engines, like higher thrust levels, were needed on the proven workhorse to prepare them for the SLS. To accommodate a higher thrust level, the number of engines was increased from three, used during the shuttle era, to four. The power level also was increased for each engine.

Engines on the shuttle ran at 491,000 pounds vacuum thrust (104.5-percent of rated power level). After analyzing temperature and other factors on the engine, the power level was increased for SLS to 512,000 pounds vacuum thrust (109 percent of rated power level).
Modifications also have been made to the A-1 test stand at Stennis to prepare for the RS-25's first hot-fire test.

(Image provided by Aerojet Rocketdyne)

FMI: www.nasa.gov