Gazebo Gazette

A landmark partnership between NASA’s Stennis Space Center and Aerojet Rocketdyne, an L3Harris Technologies company, has concluded after more than two decades of dedicated and coordinated effort in testing the world’s most powerful hydrogen-fueled rocket engine.

NASA Stennis, located near the Mississippi Gulf Coast, was selected in 1997 as the location to assemble and test RS-68 engines to power the Delta IV rocket, a United Launch Alliance vehicle used for the U.S. Air Force’s Evolved Expendable Launch Vehicle Program.

The decision paved the way for the first commercial partnership between the center and a commercial aerospace company, providing a model for future collaborations to serve NASA and all of America’s interests.

“The RS-68 program leaves a legacy that has proven invaluable to America’s space efforts,” NASA Stennis Director Rick Gilbrech said.

The Reimbursable Space Act Agreement signed between NASA and Aerojet Rocketdyne on May 18, 1998, ushered in many milestones over the duration of the partnership. Along with assembling the engine, the company modified, maintained, and operated the B-1 Test Stand for testing of the RS- 68 throughout a 25-year period as NASA Stennis became the first NASA center to lease its test facilities to a commercial company.

In its original form, the RS-68 engine generated more than 650,000 pounds of sea-level thrust with its first flight launching in November 2002. The evolved engine, RS-68A, capable of producing 705,000 pounds of thrust, first test fired at NASA Stennis in September 2008.

Following completion of certification testing, the first flight with RS-68A engines launched in June 2012.

The next time Orion flew into space came when SLS, powered by four RS-25 engines also produced by lead engine contractor Aerojet Rocketdyne, lifted off during the successful Artemis I mission in 2022.

Between military and NASA operations, RS-68 engines have a track record of 100 percent mission success. Aerojet Rocketdyne conducted the final RS-68 engine test at NASA Stennis in April 2021. Over the life of the RS-68 program, Aerojet Rocketdyne conducted 341 hot fire engine tests at NASA Stennis, recorded a total run time of 58,672 seconds, and delivered 77 flight certified production engines to power Delta IV launch vehicles.

The engines have powered 44 launches, including 15 heavy launch configurations using three core vehicles and three engines.

The final Delta IV mission is scheduled for March 2024 using the last three RS-68 production engines.