NASA’s new moon rocket uses a lot of components from the shuttle program, including the venerable RS-25 engine. Three were mounted to the shuttle itself, and the core stage of the SLS is powered by four of them. The next rocket — slated to take astronauts Reid Wiseman, Victor Glover, Christina Koch, and Jeremy Hansen to the far side of the moon — has seen a change of plans when it comes to those engines, as Stephen Clark reports:
The engine removed from the Artemis II rocket—serial number E2063—was built at NASA’s Stennis Space Center by Aerojet Rocketdyne, now part of L3Harris, a Florida-based tech company and defense contractor. Technicians finished constructing the engine in 2015. It was the last RS-25 built using leftover parts, such as turbopumps, that flew on the Space Shuttle, but the fully assembled engine has never flown before.
In its place, NASA installed E2061 into the Engine 4 position on the Artemis II core stage. This engine was the final one built for the shuttle. NASA certified the engine for flight in 2008, and it flew twice in 2010 and 2011.
While the RS-25 traces its roots back to the 1960s, it has proven to be remarkably reliable, with very few failures over the decades. Sadly, while they were reusable in the shuttle era, in the age of the SLS, they are one-and-done, which is decidedly old-fashioned in the era of launch vehicles like the Falcon 9.