Spaceflight Insider

NASA signs new Space Launch System engine contract

Space Launch System rocket lifting off from Kennedy Space Center Launch Complex 39B with Orion spacecraft NASA image posted on SpaceFlight Insider

NASA and Aerojet Rocketdyne have agreed to resume production of the RS-25 engine for use on the agency’s Space Launch System (SLS). Image Credit: NASA

On Monday, Nov. 23, NASA and Aerojet Rocketdyne (Rocketdyne) announced a $1.16 billion contract for Rocketdyne to resume production of the RS-25 engines that helped power the Shuttle to orbit for 30 years. The engines will now be used to power the agency’s new super heavy-lift vehicle, the Space Launch System (SLS), and it’s Orion capsule, to the Moon, Mars and beyond.

On Shuttle, three RS-25’s, which were reconditioned and reused, were attached to the aft end of the orbiter. For SLS, four RS-25’s will be required for each flight, and the engines will not be recovered and reused.

NASA has 16 flight-ready RS-25’s in storage at its John C. Stennis Space Center (SSC) in south Mississippi. These engines will be used on the first four SLS flights. However, for subsequent flights, additional engines will be required.

SLS RS-25 flight engine mission assignments. Photo Credit: Aerojet Rocketdyne

SLS RS-25 flight engine mission assignments. Photo Credit: Aerojet Rocketdyne

According to NASA, the new contract runs from November of this year through September of 2024, and only “restarts [Rocketdyne’s] production capability including furnishing the necessary management, labor, facilities, tools, equipment and materials required for this effort, implementing modern fabrication processes and affordability improvements, and producing hardware required for development and certification testing.” However, the contract does allow for a future modification which would enable NASA to actually order six new flight engines.

SpaceFlight Insider speaks with Aerojet Rocketdyne's Jim Paulsen. Photo Credit: Aerojet Rocketdyne

SpaceFlight Insider speaks with Rocketdyne’s Jim Paulsen on Aug. 13. Photo Credit: Aerojet Rocketdyne

Jim Paulsen, vice president, Program Execution, Advanced Space and Launch Programs at Rocketdyne, explained that the “RS-25 engines designed under this new contract will be expendable with significant affordability improvements over previous versions. This is due to the incorporation of new technologies, such as the introduction of simplified designs; 3-D printing technology called additive manufacturing; and streamlined manufacturing in a modern, state-of-the-art fabrication facility.”

The first SLS launch, Exploration Mission 1 (EM-1), an uncrewed test flight around the Moon, is scheduled for 2018. The first crewed flight, Exploration Mission 2 (EM-2), is schduled for no later than 2023, and NASA intends to fly SLS once a year thereafter, budget permitting.

Click here to view Rocketdyne’s video news release regarding new RS-25 production.

Video courtesy of NASA / Aerojet Rocketdyne


Scott earned both a Bachelor's Degree in public administration, and a law degree, from Samford University in Birmingham, Alabama. He currently practices law in the Birmingham suburb of Homewood. Scott first remembers visiting Marshall Space Flight Center in 1978 to get an up-close look at the first orbiter, Enterprise, which had been transported to Huntsville for dynamic testing. More recently, in 2006, he participated in an effort at the United States Space and Rocket Center (USSRC) to restore the long-neglected Skylab 1-G Trainer. This led to a volunteer position, with the USSRC curator, where he worked for several years maintaining exhibits and archival material, including flown space hardware. Scott attended the STS - 110, 116 and 135 shuttle launches, along with Ares I-X, Atlas V MSL and Delta IV NROL-15 launches. More recently, he covered the Atlas V SBIRS GEO-2 and MAVEN launches, along with the Antares ORB-1, SpaceX CRS-3, and Orion EFT-1 launches.

Reader Comments

Wonder if they’ll keep the name or make it something else. RS-25E (expendable)? Part of me wants to say “Hey they already did that, it’s called the RS-68”, but the other part reminds that it stripped out a lot of efficiency improvements too that meant it didn’t quite meet the thrust-to-weight needs.

Seems like the recipe for success for space programs old and new is less congressional schizophrenia / meddling, more proper Project Management.

RS-68 also has ablative nozzle which makes it unsuitable for cluster configuration without re-design with regen cooling. This was major issue with RS-68 in the original Aries V configuration.

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