Spaceflight Insider

Aerojet Rocketdyne continues development on AR1 Engine with successful CDR

Aerojet Rocketdyne tests a portion of its AR1 engine at NASA's Stennis Space Center in Mississippi. Photo Credit: Aerojet Rocketdyne

Aerojet Rocketdyne tests a portion of its AR1 engine at NASA’s Stennis Space Center in Mississippi. Photo Credit: Aerojet Rocketdyne

Aerojet Rocketdyne continues to make progress on its new AR1 engine by completing its Critical Design Review (CDR) recently. With the completion of the CDR, the engine is still on track to be certified for flight by 2019.

“This important milestone keeps AR1 squarely on track for flight readiness in 2019,” said Aerojet Rocketdyne CEO and President Eileen Drake. “AR1 ends foreign dependence, fits on existing launch vehicles with the least amount of changes to the system or on new launch vehicles in development, and is compatible with current ground and launch infrastructure.”

United Launch Alliance image of Vulcan rocket lifting off. Image Credit ULA posted on SpaceFlight Insider

Vulcan could use two of Aerojet Rocketdyne’s AR1 engines. Photo Credit: United Launch Alliance

The CDR certifies not only the design of the engine but also the manufacturing processes needed to produce the entire engine.

“Completing the CDR is a significant milestone for the AR1 program. It means that we have finalized our design and confirmed that it meets the diverse set of operational requirements necessary for national security missions,” added Drake. “Leading up to CDR, we manufactured major components at subscale and full-scale dimensions and completed hundreds of tests to confirm that we are ready to build our first engine for qualification and certification.”

The system-level CDR is the culmination of 22 incremental CDRs and critical subsystem testing, such as full-scale performance testing of the preburner and staged combustion system.

The AR1 engine is being designed to replace the Russian-built RD-180 engine which Congress has mandated the Defense Department stop using for its satellite launches.

The AR1 is fueled by liquid oxygen and kerosene, the same fuel mixture as the RD-180 engine it will replace, and produces 500,000 pounds-force (2,224 kilonewtons) of thrust at sea level.

ULA’s new rocket, named the Vulcan, is scheduled to debut in 2019 and will either replace or fly along with the reliable Atlas V booster.  Vulcan will use a new engine and the AR1 is one of two contenders to propel the new booster.

The other engine under consideration for Vulcan is Blue Origin’s BE-4 – a Liquefied Natural Gas (LNG) and Liquid Oxygen (LOX) powered engine which produces 550,000 pounds-force (2446.5 kilonewtons) of thrust at sea level.



Lloyd Campbell’s first interest in space began when he was a very young boy in the 1960s with NASA’s Gemini and Apollo programs. That passion continued in the early 1970s with our continued exploration of our Moon, and was renewed by the Shuttle Program. Having attended the launch of Space Shuttle Discovery on its final two missions, STS-131, and STS-133, he began to do more social networking on space and that developed into writing more in-depth articles. Since then he’s attended the launch of the Mars Science Laboratory Curiosity rover, the agency’s new crew-rated Orion spacecraft on Exploration Flight Test 1, and multiple other uncrewed launches. In addition to writing, Lloyd has also been doing more photography of launches and aviation. He enjoys all aspects of space exploration, both human, and robotic, but his primary passions lie with human exploration and the vehicles, rockets, and other technologies that allow humanity to explore space.

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