March 11, 2016

— A rocket engine that helped launch five space shuttle missions, including the penultimate flight of the program in 2011, was fired again on Thursday (March 10) in preparation for the first crewed flight of NASA's new heavy-lift rocket.

The space agency successfully test fired the RS-25 rocket engine for a full 500 seconds, clearing a milestone towards its exploration goals. The next time that particular engine, serial number 2059, fires for that length of time, it will be to launch astronauts on NASA's first crewed mission beyond Earth orbit since the last of the Apollo moon missions more than 45 years ago.

"What a great moment for NASA," said Rick Gilbrech, the director of NASA's Stennis Space Center in Bay St. Louis, Mississippi, where Thursday's hot fire test took place. "We have exciting days ahead with a return to deep space and a journey to Mars, and this test is a very big step in that direction."

Click to enlarge and view the video in a pop-up window. (NASA)

The 8-minute-long firing marked the first test of an RS-25 flight engine for NASA's new Space Launch System (SLS) rocket, being built to carry humans on future missions into the solar system, including to the moon's vicinity and Mars. Four of the engines, formerly known as space shuttle main engines (SSME), will help power the SLS core stage.

The engines NASA will use for the initial SLS missions are from the 16 flight articles remaining from the retired shuttle program. No. 2059 last flew as one of the three engines on the final flight of the space shuttle Endeavour, STS-134, in May 2011. The mission was the second to last flight for the orbiter fleet overall.

Prior to that, SSME 2059 helped launch the shuttle Atlantis on three missions, including two to the International Space Station – STS-117 in 2007 and STS-122 in 2008 – and on the final mission to upgrade the Hubble Space Telescope, STS-125 in 2009. It also helped power Endeavour's STS-130 flight to deliver the Tranquility node and cupola to the space station in 2010.

"It's a great feeling that this engine – that has carried so many astronauts into space before – is being prepared to take astronauts to space once again on SLS's first crewed flight," stated Steve Wofford, engines manager at Marshall Space Flight Center in Alabama, where the Space Launch System program is managed for NASA.

Modified for use on SLS, no. 2059 and three other shuttle-legacy RS-25D engines will fire at 109 percent thrust level and provide a combined two million pounds of thrust when they fly in the 2020s. Unlike on the shuttle, they will not be recovered for reuse, but instead be dropped into the ocean with the spent SLS core.

The RS-25 engine No. 2059 arrives at the A-1 Test Stand at NASA's Stennis Space Center on Nov. 4, 2015. (NASA)

The first flight of the SLS on NASA's uncrewed Exploration Mission-1 (EM-1) is slated for 2018 or 2019. The first SLS launch with astronauts aboard an Orion crew spacecraft is targeted for the 2021 to 2023 timeframe, depending in part on available funding.

Stennis and Aerojet Rocketdyne, NASA's prime contractor for the RS-25, will next conduct a development engine hot fire series to test flight engine controllers and will continue to test RS-25 flight engines.

In addition, the B-2 Test Stand at Stennis is being readied to test the SLS core stage for EM-1, firing its four engines together. EM-1 will lift off using engines 2045, 2056, 2058 and 2060, which includes two of the three SSMEs that flew on board STS-135, the final shuttle mission, in July 2011.

In addition to 2059, EM-2 will launch with RS-25 engines 2047, the third engine flown on STS-135, and two engines that were built up after the space shuttle was retired, 2062 and 2063.