Combustion Stability Confirmed For 7500-Pound Thrust Motor

Development injector testing for the 7500-pound thrust Orion main engine (OME) for NASA's Orion crew exploration vehicle has recently been completed successfully by Aerojet under contract to Lockheed Martin. The OME is a pressure-fed, regeneratively cooled, storable bi-propellant engine that is a technically advanced, increased performance version of Aerojet's 6000-pound thrust space shuttle Orbital Maneuvering System Engine (OMS-E).

The test series verified the engine's combustion stability and additionally provided chamber wall heat flux and injector performance data to anchor mathematical models. All testing was performed in heavy-weight combustion chambers specifically designed for these tasks. This early demonstration of the engine's combustion stability at expected Orion operating conditions was conducted to retire risk to the Orion vehicle.

"The successful qualification combustion stability testing of the OME injector was the result of a structured approach used to design, analyze, build and test the first development injector," said Aerojet's Orion Program Manager, Cheryl Rehm. "The team's meticulous attention to detail resulted in a product that met and exceeded our expectations."

File Photo NASA Image

The OME injector combines the reliability and combustion stability of the OMS-E injector with current Aerojet best practices in design and manufacturing to reduce process variability affecting injector performance and cost for the Orion program. The OME injector is a diffusion-bonded platelet device with the same injector element type, face pattern layout, and element quantity as the OMS-E, but with improvements in the injector body design and platelets to provide more uniform flow to the injector elements.

The current Aerojet platelet manufacturing capability results in significantly less dimensional variability than was possible for the OMS-E, enabling improved uniformity of propellants injected into the combustion chamber. The improvements in injection uniformity are also expected to result in improved nominal and minimum vacuum specific impulse for the OME.

Orion Crew Module Final Weld NASA Image

The OME will provide thrust for events requiring large velocity changes such as Earth orbital insertion, translunar/trans Earth injection, Earth de-orbit, and emergency thrust for high-altitude abort scenarios. Orion's engine complement also includes 16 25-pound thrust engines and eight 100-pound-thrust bipropellant engines for the Orion service module. Additionally, Aerojet supplies 12 160-pound-thrust monopropellant thrusters for the Orion crew module. Aerojet is providing all of the engines for the Orion spacecraft which is comprised of a crew module for crew and cargo transport, and a service module for propulsion, electrical power and fluids storage. Risk reduction testing of critical subsystems has been ongoing throughout Orion's development phase to maximize mission success and crew safety.

FMI: www.Aerojet.com