Aerojet Rocketdyne Completes CDR on AR1 Engine

AR-1 engine (Credit: Aerojet Rockettdyne)

LOS ANGELES, May 08, 2017 (Aerojet Rocketdyne PR) — Aerojet Rocketdyne, a subsidiary of Aerojet Rocketdyne Holdings, Inc. (NYSE:AJRD), successfully completed its Critical Design Review (CDR) for AR1, a 500,000 lbf thrust-class, liquid-fueled rocket engine.

The milestone keeps the AR1 on track for certification for flight in 2019 as a replacement for the Russian RD-180 engine that is used today to launch most U.S. national security payloads. The U.S. Congress has mandated that the Defense Department discontinue using Russian engines to launch its satellites into space. AR1 is the lowest-risk, lowest-cost-to-the-taxpayer and fastest path to eliminating U.S. dependence on foreign suppliers.

“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.”

The CDR not only focused on the AR1’s detailed design to ensure that it meets the rigorous performance requirements of a booster engine prior to full-scale manufacturing, it also validated the production processes that will be used to produce the flight engines. The comprehensive review was attended by government and industry experts who are independent of the program. These experts viewed and assessed the program’s readiness and confirmed the technical effort is on track.

“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. Additionally, more than 200 engine system-level design requirements have now been established and verifications are in place.

“Using our proven development methodology that has been honed during decades of designing booster engines such as the RS-68 and RS-25, Aerojet Rocketdyne will have an engine certified and ready for production in 2019,” said Julie Van Kleeck, vice president of Advanced Space and Launch Programs and Strategy. “Aerojet Rocketdyne understands the exacting engine development and launch vehicle integration processes required for National Security Space missions. We have the resources and capabilities in-place to support national security launches using the AR1 as the booster engine starting in 2020.”

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 .

  • roflplatypus

    So what’s the AR-1 going to be used for? ULA has pretty much confirmed they’re going for the BE-4 once it gets tested, and ULA also doesn’t want to give up the rights to the Atlas V ( On the other hand, I’ve read that the cost of developing a rocket engine is most of the cost of designing a rocket, so with AR already making the RL-10, maybe they could make their own booster/rocket or market the AR-1 to other companies, like Orbital ATK with their planned HLV? Clearly they have some plan because they are sticking with this very expensive development process.

  • passinglurker

    They are probably sticking to it because they are being paid to. This wouldn’t be the first engine the government paid to have developed that went nowhere.

    Meanwhile the monkey wrench in the idea that aerojet could go vertical and come out with thier own launch service is again blue origin and spaceX. The trend towards reusability while likely not eliminating the case for expendables for decades is certainly gonna shrink the niche that is already gonna be crowded.

    With With ULA and Orbital ATK vying for the expendable military market and everyone other incumbent in the world vying for the expendable commercial market if Aerojet jumps in with a vanilla ar-1 powered rocket they will be a newcomer with none of the technological advantages of new space, nor any of the reputation advantages of old space.

    Aerojet might make a bid for reusability but the AR-1 isn’t really an engine for landing falcon style meaning they’d either need to take ULA’s SMART approach or make a winged lifter that lands on a runway.

  • JamesG


    While on the face of it this seems a classic example of “late to market”, there is no telling what kind of back room deals are lurking in the cigar smoke.

  • Larry J

    AJR is hoping the AR-1 will yet be used to re-engine the Atlas V. From what I’ve heard, ULA is only funding development of the Vulcan a quarter at a time. If something delays the BE-4 (new company, new technology, new propellants), then the Vulcan design could use the AR-1 or ULA might stick with the Atlas. There’s also the possibility of putting 4-6 AR-1s in each of the strap-ons to replace the 5-segment SRBs for SLS should that project survive to Block 1A or Block 2.

  • Tom Billings

    Basically, if BE-4 undergoes any prolonged development problems, Tori Bruno is replaced, and Vulcan is dropped. Then AR-1 powers an expendable “Atlas-6”. It also means that ULA tubes before 2030, but its current BoD will have retired by then.

    However that all turns out, the members who sit on the appropriations committees will keep sending money to develop AR-1. It because of their policies that R&D has become the great profit center of the cost+ contractor community. AeroJet cannot afford to refuse the money.

  • passinglurker

    LRB’s for SLS is highly unlikely the advance booster competition was basically scrapped when the terms were changed to solids only to save time and money on changes to the ground infrastructure. Maybe if Aerojet wants to foot the bill for running the kerosene and lox pipes themselves?

  • Mr Snarky Answer

    Engine to no where

  • Arthur Hamilton

    They are too expensive. Maybe another start up will come along and buy the engine.

  • JamesG

    Not unless Apple Inc. is going into the rocket biz.

  • Jeff2Space

    With ATK planning on flying very large composite wound boosters on its Next Generation Launch Vehicle (currently under development). I would fully expect them to pitch composite wound “advanced” boosters for SLS (if they aren’t doing so already).

    Think about it. Even if NGLV isn’t profitable, it is performing a large part of the development work needed for “advanced” solids for SLS.

  • passinglurker

    Yeah despite relying on that money hole SLS it’s hard not to admire the quiet brilliance behind Orbital ATK ‘s NGL plan with all the development, component, infrastructure, and cost sharing involved.

  • publiusr

    Vulcan and New Glenn might wind up being the same rocket/