Spaceflight Insider

NASA signs new Space Launch System RS-25 engine contract

A CGI depiction of an SLS launch from Kennedy Space Center.

A CGI depiction of an SLS launch from Kennedy Space Center. The SLS will utilize RS-25 engines in its 1st stage. Image Credit: NASA

On Monday, Nov. 23, 2015, NASA and Aerojet Rocketdyne announced a $1.16 billion contract for Aerojet 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 its 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 the 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

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

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

According to NASA, the new contract runs from November of this year through September of 2024, and only “restarts [Aerojet 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.

Jim Paulsen, vice president, Program Execution, Advanced Space and Launch Programs at Aerojet 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 scheduled for no later than 2023, and NASA intends to fly the SLS once a year thereafter, budget permitting.

Click here to view Aerojet 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.

⚠ Commenting Rules

Post Comment

Your email address will not be published. Required fields are marked *