Aerojet Rocketdyne’s AR1 Engine Sets U.S. Record

Staged-combustion testing at NASA’s Stennis Space Center in Mississippi for the AR1 program is being developed by Aerojet Rocketdyne. (Credit: Aerojet Rocketdyne)

STENNIS SPACE CENTER, Miss., (Aerojet Rocketdyne PR) – Aerojet Rocketdyne, a subsidiary of Aerojet Rocketdyne Holdings, Inc. (NYSE:AJRD), recently demonstrated the highest chamber pressure of any United States produced liquid oxygen and kerosene main combustion system. This milestone occurred during a series of successful test firings of the AR1’s staged combustion system at NASA’s Stennis Space Center.

Preparations for the staged-combustion testing began at Stennis last summer, pushing the limits of the nation’s premier large engine development test facility. During this testing, Aerojet Rocketdyne combined the engine’s preburner with the main injector in order to validate injector design parameters and performance.

“Staged-combustion testing is a critical step in proving our design for AR1 and reestablishing U.S. preeminence in hydrocarbon space launch propulsion,” said Aerojet Rocketdyne CEO and President Eileen Drake. “We have been working diligently on the AR1 program since 2014 and remain on target to deliver a flight-qualified AR1 engine in 2019 as promised. The latest testing validates our flight design and provides high confidence as we move further into AR1 engine manufacturing.”

The AR1 engine is being developed as a replacement for Russian-made engines currently used on domestic rockets. AR1 is a 500,000 lbf thrust-class liquid oxygen/kerosene booster engine that incorporates the latest advances in rocket engine technology, materials science and modern manufacturing techniques to deliver an affordable, reliable booster engine quickly.

“AR1 is the lowest risk, lowest cost and fastest path to end U.S. reliance on Russian engines for the launch of America’s national security and civil space missions,” added Drake.

Aerojet Rocketdyne is an innovative company delivering solutions that create value for its customers in the aerospace and defense markets. The company is a world-recognized aerospace and defense leader that provides propulsion and energetics to the space, missile defense and strategic systems, tactical systems and armaments areas, in support of domestic and international markets. Additional information about Aerojet Rocketdyne can be obtained by visiting our websites at and

  • windbourne

    I thought that Delta (an H2 rocket) is dead, and that atlas was to be converted to methane?

  • passinglurker

    Delta is slated to be retired yes, and the current plan was to replace the atlas first stage with vulcan a LNG fueled rocket stage powered by a blue origin engine. Though not if Aerojet gets thier way they’d rather ULA buy thier engine instead which would leave atlas relativly unchanged or so aerojet claims. Though ULA has said that assuming the BE-4 engine doesn’t suffer delays integrating the AR-1 would actually take longer because it would be ready later and they’d still want to redesign and stretch the stage anyway to take advantage of the added thrust.

    So basically aerojet is saying(mostly to congress) that they could just slap this in place of a russain engine and be flying in no time if enough (taxpayer) money is thrown at them, and it may be true, but ULA is saying that this won’t result in a rocket that would be competitive in today’s, or tomorrow’s market which is why thier plans point to more drastic changes and longer time tables than what Aerojet is selling

  • Zed_WEASEL

    The Delta IV is not quite dead. Since the new Vulcan uses the tooling from the Delta IV. And the Delta IV Heavy will continue flying until there is a replacement in service, at about a $1B each..

    If ULA have to use the AR-1.than basically they are developing a new launch vehicle. Since the structural load paths are totally different.

    The US already got a replacement for the RD-180 in the form of products from Hawthorne. Which ULA have to find something similar in performance and price to be competitive.

    The AR-1 is about 8 years too late to start.development. The SpaceX Raptor and the Blue BE-4 will be available years before the AR-1. It is too late for Aerojet Rocketdyne. Don’t see a future for them with large motors for launch vehicles.

  • JamesG

    LOX/RP1… Thats so quaint. So last century.

    And that combustor does not look like flight hardware. In fact it looks like it should be on a high-pressure oil well somewhere.

  • Aerospike

    How they boast about the highest chamber pressure, but don’t even provide the actual value.

  • windbourne

    at 1B / DIVH, I think it is fair to say that it is done except for already scheduled.

    Personally, I think that AR would be smart to start developing their own rockets. They probably have the best R&D on engines so, without owning ULA, they would be smart to compete against the others.

  • Jeff2Space

    Do note that AR could have done this “on their own” long ago. But, they have shown a stubborn reluctance to develop “big” engines on their own dime. They would much rather wait for the government to pay for the majority of the development costs. Here’s a cite for how they’re paying for AR-1. In short, 2/3 of the money is coming from the USAF.

  • Paul451

    “the highest chamber pressure of any… United States produced… liquid oxygen and kerosene… main combustion system…”

    “on a Tuesday… in February… in an odd-numbered year…”

  • windbourne

    AR is old space like Boeing, ULA, L-Mart, etc. And they ALL want lucrative cost+ contracts, rather than going after the big bucks mostly on their own.

  • Zed_WEASEL

    Well AeroJet Rocketdyne have to beat the 300 bars (4351 PSI) chamber pressure in the full flow staged combustion MethoLox engine from Hawthorne.

    Maybe they are just referring to staged combustion KeoLox engines.