Aerojet Rocketdyne recently completed a series of hot-fire tests of additive manufactured components for its AR1 booster engine at its Sacramento test facility. AR1 is the first advanced hydrocarbon large liquid rocket engine in development by Aerojet Rocketdyne since the merger of Aerojet and Pratt & Whitney Rocketdyne in June 2013.
The single-element main injector hot-fire tests were conducted to evaluate various main injector element designs and fabrication methods. Several injectors were fabricated using selective laser melting (SLM), a form of additive manufacturing (AM). AM has become so ubiquitous throughout the industry because it allows for the production of complex engine components at a fraction of the cost of those produced using traditional manufacturing techniques.
Aerojet Rocketdyne has invested heavily in developing SLM capabilities for application to its rocket engines. Tested in excess of 2000 psi, Aerojet Rocketdyne believes the AR1 single-element hot-fire tests represent the highest pressure hot-fire test of an AM part in a rocket engine application. In the main injector alone, AM offers the potential for a nine-month reduction in part lead times, and a 70% reduction in cost.
The AR1 is a 500,000-lb thrust-class liquid oxygen/kerosene booster engine currently in development as an alternative to the Russian-built RD-180. The 2015 National Defense Authorization Act calls for the RD-180 to be replaced by an American-made alternative for national security space launches by 2019. The AR1 is expected to be a catalyst for U.S. launch providers to compete more effectively in the global commercial launch marketplace.
AR1 development began in 2014 and builds on Aerojet Rocketdyne’s staged combustion experience gained through technology development programs as well as its recent AFRL Hydrocarbon Boost Technology Demonstration and the NASA Advanced Booster Engineering Demonstration/Risk Reduction program. All three programs are part of the company’s Advanced Hydrocarbon Propulsion Development Office (AHPDO) in Huntsville, AL.
Rapid development and certification of the AR1 for current and future national security launch vehicles is a key focus for AHPDO, particularly in terms of engine cycles, materials, and AM. The AHPDO office will integrate AR1 development and production activities across Aerojet Rocketdyne's various sites. The company's Los Angeles and Sacramento facilities will offer advanced large rocket engine engineering and specialized manufacturing expertise, the West Palm Beach facility will offer additional manufacturing and assembly work, and Aerojet Rocketdyne's Stennis facility will be used for AR1 engine final assembly and could begin to test as early as 2017, with certification targeted for 2019.
The AR1 is designed to integrate with the Atlas V launch vehicle, as well as provide a versatile propulsion solution for multiple current and future launch vehicle applications. “When you consider the minimal changes to the Atlas V launch vehicle, launch pad, and related infrastructure that are required with an AR1 solution, this approach is clearly the best path toward finding a replacement for the RD-180,” said Linda Cova, Executive Director of Hydrocarbon Engine Programs at Aerojet Rocketdyne.
Development of AR1 is currently being funded by Aerojet Rocketdyne with assistance from United Launch Alliance (ULA). Aerojet Rocketdyne and ULA also continue to support the Atlas and Delta launch vehicles such as the RS-68A, RL10, and AJ-60A.
Work on the AR1 full-scale design has been progressing steadily with the team achieving significant milestones over the past months, including the completion of a System Requirements Review, full-scale single-element main injector hot-fire testing, subscale preburner testing, and turbopump inducer testing.
Completion of a vehicle-level system concept review and a main propulsion system Preliminary Design Review are planned major milestones for 2015.