Spaceflight Insider

Final RS-25 hot-fire test of 2017 completed

An Aerojet Rocketdyne technician inspects the 3-D printed pogo accumulator assembly on an RS-25 development engine at the Aerojet Rocketdyne facility located at NASA’s Stennis Space Center. Photo & Caption Credit: Aerojet Rocketdyne

An Aerojet Rocketdyne technician inspects the 3-D printed pogo accumulator assembly on an RS-25 development engine at the Aerojet Rocketdyne facility located at NASA’s Stennis Space Center. Photo & Caption Credit: Aerojet Rocketdyne

NASA and Aerojet Rocketdyne have conducted the final RS-25 hot-fire test of 2017 at their Stennis Space Center in Mississippi. The six-minute, 40-second test was conducted at Stennis’ A-1 Test Stand. The test also continued the development of components that utilized additive manufacturing, more commonly known as “3-D printing”.

The test conducted today was known as a “green-run test” and utilized a 3-D printed RS-25 flight controller part. This was the eighth RS-25 test of the year and the sixth flight controller overall to be tested for NASA’s Space Launch System (SLS) rocket.

The SLS is the U.S.’ next launch vehicle designed to send crews to the Moon and perhaps, one day, Mars. The flight controller tested is about the size of a beach-ball and is called a POGO accumulator assembly. This part is used as a kind of “shock absorber” which will dampen vibrations, or oscillations, which are caused by the rocket propellants as they flow down the fuel system between the launch vehicle and the engine itself.

“This test demonstrates the viability of using additive manufacturing to produce even the most complex components in one of the world’s most reliable rocket engines,” Eileen Drake, CEO and president of Aerojet Rocketdyne said via a release issued by the company. “We expect this technology to dramatically lower the cost of access to space.”

NASA’s launch vehicle fabrication partners across the U.S. are working to develop and produce components and flight hardware for this new rocket using techniques like additive manufacturing or 3-D Laser Printing.

It is hoped that this will help replace the 16 RS-25 engines that are currently being used (or planned for use). These are, essentially, modified leftover engines from the Space Shuttle Program. It is hoped that the use of 3-D printed components will allow for the costs of producing these elements to be lowered.

NASA has stated that the 3-D printed component performed as expected.

At present, the first SLS flight will be Exploration Mission 1, or EM-1, which will be an unmanned test flight of the Orion Multi-Purpose Crew Vehicle on an uncrewed lunar orbital test flight. The following flight will be EM-2 which will be the first crewed mission to the Moon since Apollo 17 flew to the Moon in December of 1972. It is hoped that EM-2 will take place in the 2022–2023 time frame.

“As Aerojet Rocketdyne begins to build new RS-25 engines beyond its current inventory of 16 heritage shuttle engines, future RS-25 engines will feature dozens of additively-manufactured components,” said Dan Adamski, RS-25 program director at Aerojet Rocketdyne via a company-issued release. “One of the primary goals of the RS-25 program is to lower the overall cost of the engine while maintaining its reliability and safety margins. Additive manufacturing is essential to achieving that goal.”

The A-1 and A-2 test stands were created during the Apollo era to test the J-2 engines for the Saturn V Moon rockets second stage known as the S-II.

Video courtesy of NASA Stennis



A native of Lonedell, Missouri, Michael McCabe is a former Long Island firefighter and emergency medical technician. He is a non-active Florida EMT with 20 years of fire rescue experience. He is also a lifelong science fiction and space enthusiast. At the age of 10, he watched in his school classroom as the Space Shuttle Challenger exploded in 1986. In 2008, he moved to the Sunshine State and works as a private tour guide at Kennedy Space Center Visitor Complex for a private company based in Orlando. McCabe has been a fan of SpaceFlight Insider since our inception in 2013. He reached out to ask how he could assist our efforts to spread space flight awareness. Shortly thereafter, he was welcomed into our expanding team.

Reader Comments

I don’t know about you, but every time I hear of some development coming out of the “Stennis” center in Mississippi, I cannot help but remember that it was named after U.S. Senator John Stennis who was a zealous supporter of racial segregation. He signed the Southern Manifesto, which called for resistance to the Supreme Court ruling in Brown v. Board of Education. He also voted against the Civil Rights Act of 1964, the Voting Rights Act of 1965, and the Civil Rights Act of 1968. He voted against the establishment of Martin Luther King Jr. Day as a holiday. I’d like to have that center re-named, possibly after someone good.

Half a million pounds of go with an Isp of 452 seconds. That is how we go back to the Moon.

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