Engineers at the Marshall Space Flight Centre have begun a series of engine tests on a new breed of space propulsion: a Reaction Control Engine developed for the Space Launch Initiative (SLI). The technology was developed to establish reliable, affordable space access.
The engine, developed by TRW Space and Electronics is an auxiliary propulsion engine designed to manoeuvre vehicles in orbit. It is used for docking, re-entry and attitude control while the vehicle is in orbit.
The engine is said to use non-toxic chemicals as propellants, a feature that creates a safer environment for ground operators, lowers cost and increases efficiency with less maintenance and quicker turn-around time between missions. As part of its SLI work, the Marshall Centre is testing multiple engine designs using different propellant combinations, including liquid oxygen as the oxidiser and liquid hydrogen or ethanol as the fuel.
Testing is said to include 30 hot-firings. This is the first engine test performed at the Marshall Centre that includes SLI technology. The Marshall Centre is testing the reaction control engine using liquid oxygen as an oxidiser and liquid hydrogen as fuel.
‘The combination of liquid oxygen and liquid hydrogen was chosen because it offers one of the highest performances in conventional liquid engines,’ said Robert Champion, main propulsion/auxiliary propulsion systems project manager for the Space Launch Initiative.
Liquid hydrogen does have its drawbacks, however, as it must be stored at the extreme temperature of -423 F. ‘By testing various fuel combinations we are able to determine which engine will best suit the requirements needed for the reusable launch vehicle,’ added Champion.
Another feature of the reaction control engine is that it operates at dual thrust modes, combining two engine functions into one engine. The engine operates at both 25 and 1,000 pounds of force, reducing overall propulsion weight and allowing vehicles to easily manoeuvre in space.
The low-level thrust of 25 pounds of force allows the vehicle to fine-point manoeuvre and dock while the high level thrust of 1,000 pounds of force is used for re-entry, orbit transfer and coarse positioning.
Space Launch Initiative is a NASA-wide research and development program, managed by the Marshall Centre, designed to improve safety, reliability and cost effectiveness of space travel for second generation reusable launch vehicles.