Proven Engine Packs Big, In-Space Punch for NASA’s SLS Rocket

The thundering roar of a rocket leaving the launch pad is a familiar sight. Much less familiar is the job of the smaller upper stage engines that do their job mostly beyond eye and camera range, but give spacecraft the big, in-space push they need to venture into deep space. NASA’s new rocket, the Space Launch System (SLS), will rely on a proven upper stage engine – the RL10 – for its first mission with the agency’s Orion spacecraft in late 2018. The SLS Block 1 rocket will use one RL10B-2 engine, the same engine currently used by the Delta IV rocket, as a part of the interim cryogenic propulsion stage (ICPS).

As the rocket evolves to a more powerful Block 1B configuration, an exploration upper stage (EUS) will be added. The EUS will use four RL10C-3 engines, and the upgraded rocket will send astronauts tens of thousands of miles beyond the moon to explore deep-space, paving the way for NASA’s Journey to Mars. To achieve these deep space missions, NASA recently contracted with Aerojet Rocketdyne of West Palm Beach, Florida for the production of 10 RL10C-3 engines for the rockets second and third flights with Orion, as well as two spare engines.

“The RL10 is a very technically mature engine design,” said Steve Wofford, SLS Liquid Engines manager at NASA's Marshall Space Flight Center in Huntsville, Alabama, where the SLS Program is managed. “It has been the nation’s upper stage workhorse engine for more than 50 years and is second to none in performance and demonstrated reliability. It also leverages existing propulsion technology to provide SLS with a robust engine in a timely manner and avoids costs associated with a new engine development program.”