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Successful SLS Core Stage Hot-Fire Test Puts America One Step Closer to Returning to the Moon

Written by: Space Foundation Editorial Team

STENNIS SPACE CENTER, Miss., March 18, 2021 – The four Aerojet Rocketdyne RS-25 rocket engines that power the core stage of NASA’s Space Launch System (SLS) fired in unison for the second time on March 18 in Test 8 of the Core Stage Green Run series. The successful completion of this test brought America’s heavy-lift deep space exploration rocket one step closer to its first flight.

“This is a huge milestone for the world’s largest rocket stage as it marks the most challenging test before all of the SLS hardware is assembled at NASA’s Kennedy Space Center in preparation for the Artemis I mission,” said Eileen P. Drake, Aerojet Rocketdyne CEO and president. “SLS has been designed specifically for exploration and is key to returning American astronauts to the Moon and eventually sending humans to Mars.”

This second hot fire of the four engines was the culminating event of NASA’s SLS “Green Run” test campaign that began last year and allowed the team to build upon the data collected during the initial hot fire that occurred on Jan. 16.

The Green Run test series put the vehicle’s 212-foot core stage through an end-to-end system test with fully-tanked cryogenic propellants while validating the functionality of the stage’s engines and avionics. The Aerojet Rocketdyne RS-25 engines fired together for 499 seconds, generating more than 1.6 million pounds of combined thrust and simulated the profile of an actual SLS flight, including throttling sequences.

“This is the flight article, and the successful Green Run test demonstrates the core stage, which is part of the world’s most powerful rocket, is ready for flight,” added Jim Maser, Aerojet Rocketdyne’s senior vice president for Space. “The SLS rocket can carry more cargo to more distant places than the Space Shuttle, and generates more thrust at launch than the Saturn V rocket that powered the Apollo missions. The increased payload capacity provided by SLS translates into fewer launches and simpler mission operations, which decreases risk and associated costs with intricate missions.

The core stage will now undergo post-test inspections before making the trip by barge to NASA’s Kennedy Space Center in Florida in preparation for the first flight. During its inaugural mission, known as Artemis I, the SLS rocket will launch NASA’s Orion exploration vehicle on an uncrewed mission around the Moon and back to Earth.

About Aerojet Rocketdyne: Aerojet Rocketdyne, a subsidiary of Aerojet Rocketdyne Holdings, Inc. (NYSE:AJRD), is a world-recognized aerospace and defense leader that provides propulsion systems and energetics to the space, missile defense and strategic systems, and tactical systems areas, in support of domestic and international customers. For more information, visit and Follow Aerojet Rocketdyne and CEO Eileen Drake on Twitter at @AerojetRdyne and @DrakeEileen.


Media Contacts:

Mary Engola, Aerojet Rocketdyne, 571-289-1371
[email protected]

Todd McConnell, Aerojet Rocketdyne, 561-882-5395
[email protected]