Spaceflight Insider

Flight controllers for first four Space Launch System missions delivered to Stennis

RS-25 rocket engines at Kennedy Space Center in Florida. Photo Credit: Jason Rhian SpaceFlight Insider

Aerojet Rocketdyne RS-25 rocket engines at NASA’s Kennedy Space Center in Florida. Photo Credit: Jason Rhian / SpaceFlight Insider

The flight controllers for the first planned flights of NASA’s massive Space Launch System (SLS) rocket are now in the hands of those refurbishing the RS-25 engines that will help power the SLS’ first stage.

Aerojet Rocketdyne took possession of the Honeywell-produced hardware late last month (October of 2018). The flight controllers help guide the RS-25 as they propel the SLS aloft.

In essence, these controllers “talk” with SLS and handle an array of other tasks such as monitoring the health and performance of the engines and regulating their thrust levels.

“The RS-25 program continues to achieve important milestones as we work toward the initial round of flights of America’s newest exploration rocket,” said Eileen Drake, Aerojet Rocketdyne CEO and president via a company-issued release. “We look forward to continuing to outfit the 16 engines remaining in our inventory from the shuttle with these upgraded controllers.”

Aerojet Rocketdyne now has 18 of the new controllers. This includes a spare, a qualification unit and 16 flight units. Aerojet Rocketdyne is currently putting these components through their paces with the latest test taking place on Oct. 31. During which the ground test-article of the RS-25 flared to life during a test that ran just shy of eight and-a-half minutes (this marked the 13th test of one of the new flight controllers).

The RS-25 is a modified version of the Space Shuttle Main Engine, which was used during the 30 years NASA’s now-retired fleet of orbiters were in service. As one might imagine, systems that can trace their lineage back to the 60s require a 21st Century upgrade. Each RS-25 is capable of producing an estimated 512,000 pounds of thrust at altitude.

The four RS-25s that have been selected for use on SLS’ maiden flight, Exploration Mission 1, are at NASA’s Stennis Space Center located in Mississippi. If everything goes as advertised EM-1 should take to Florida’s skies in 2020 from Kennedy Space Center’s Launch Complex 39B.





Jason Rhian spent several years honing his skills with internships at NASA, the National Space Society and other organizations. He has provided content for outlets such as: Aviation Week & Space Technology,, The Mars Society and Universe Today.

Reader Comments

Are you sure this picture is from KSC? Looks a lot like what I’ve seen at Stennis.

Nov. 5, 2018

Hi Byron,
I took this picture at KSC. I hope that clears up your confusion.
Sincerely, Jason Rhian – Editor, SpaceFlight Insider

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