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 Bay St. Louis, Mississippi, 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 work with Aerojet Rocketdyne really laid the groundwork for commercial partnership efforts of today. It has been a privilege to work with the company through these years to support the nation’s critical launch capabilities.”
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. With the close of the agreement, Aerojet Rocketdyne has returned the test stand to NASA.
In its original form, the RS-68 engine generated more than 650,000 pounds of sea-level thrust with its first flight launching 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.
Additionally, the Delta IV rocket powered by RS-68 engines tested at NASA Stennis flew NASA’s Orion spacecraft for its first mission called Exploration Flight Test-1 in 2014 as NASA’s SLS (Space Launch System) rocket was under development.
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.
Mike McDaniel, Aerojet Rocketdyne general manager at NASA Stennis, has helped steer the RS-68 engine program since his arrival at NASA Stennis in 1999 and continues to lead the company’s RS-25 engine work on site. McDaniel noted that the same processes used for the RS-68 engine program have been incorporated into work on RS-25 engines at the facility.
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. Since that time, crews used a certification engine to maintain test stand and workforce readiness in the event any RS-68 engines needed retesting.
“The relationships formed, and freedom of information shared, are some of the highlights from the program,” McDaniel said. “Talking about how the test stand functions and what we are doing with the test stand to ensure we are taking care of a NASA asset, that communication – everything from the safety part of it, to the quality, to keeping open communication and trust – contributed to the success.”
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.
“We met the customer schedule, met the customer cost, and the engines have delivered 100 percent mission success,” McDaniel said. “When you take that into account, it shows the success of the program at NASA Stennis.”
