The successful engine test marks a major milestone for the rocket that’s due to get an uncrewed round-the-moon test flight off the ground late this year or in early 2022 — and for an Artemis program that’s due to put astronauts on the lunar surface in the mid-2020s.
“The SLS is the most powerful rocket NASA has ever built, and during today’s test the core stage of the rocket generated more than 1.6 million pounds of thrust within seven seconds,” acting NASA Administrator Steve Jurczyk said in a news release. “The SLS is an incredible feat of engineering and the only rocket capable of powering America’s next-generation missions that will place the first woman and the next man on the moon.”
The Aerojet Rocketdyne RS-25 rocket engines are holdovers from the space shuttle program that have been refurbished for reuse on the SLS. Those engines consume more than 733,000 gallons of super-chilled liquid hydrogen and oxygen for their full duration.
During Jan. 16’s “Green Run” test at NASA’s Stennis Space Center in Mississippi, the SLS core stage’s RS-25 engines fired for a little more than a minute before shutting themselves down. Engineers determined that the shutdown occurred when pressure in a hydraulic system exceeded its conservative pre-set limits. Adjustments were made for today’s second test at Stennis.
This time around, the engines fired for 499.6 seconds straight, achieving 109% of the power that would be required during the 212-foot-tall booster’s eight-minute ascent to Earth orbit. The engines were also put through a series of movements in specific patterns to direct their thrust.