Northrop Grumman has successfully hot-fire tested a new type of rocket engine specifically designed to use oxygen and methane propellants that range from all-gas to all-liquid at the inlet to the thruster.
The 100lbf-thrust TR408 is a simple design that uses only two propellant valves, no moving parts other than valves, and contains a built-in spark igniter to initiate combustion of injected propellants. The reaction control engine operates under short pulse and steady-state modes.
The engine is unique in that it can fully vapourise both the oxidiser (liquid oxygen) and fuel (liquid methane) by passing these propellants through cooling passages located in the thrust chamber wall before injecting them into the chamber for combustion.
If gaseous instead of cryogenic liquid propellants are fed to the engine, the gases still provide cooling and will enter the injector at a higher temperature.
Previous rocket engine designs using propellant to cool the chamber do not vapourise any of the propellant or may only vapourise one of the propellants, typically the fuel.
The ability to operate under a broad range of inlet conditions is critical for reducing the complexity and weight of cryogenic propulsion systems that perform random pulsing for attitude control.
The development of the new rocket engine was performed under contract to NASA’s Glenn Research Center on the Cryogenic Reaction Control Engine program, awarded to Northrop Grumman in February 2006.
Hot-fire testing under vacuum conditions was performed at Northrop Grumman’s Capistrano Test Site located in San Juan Capistrano, California.