445N (100lbf) Liquid Oxygen / Liquid Methane Reaction Control Engine Technology Development for Future Space Vehicles
- Paper ID
273
- author
- company
- country
United States
- year
2008
- abstract
The NASA Exploration Systems Architecture Studies (ESAS) along with multiple other NASA study activities have identified that Liquid Oxygen (LO2)/Liquid Methane (LCH4) propulsion systems are a promising option for some future space vehicles, due to a substantial savings in overall systems mass when compared to conventional hypergolic systems. NASA's Exploration Technology Development Program (ETDP) has formed a project called Propulsion Cryogenic Advanced Development (PCAD) to support the methane technology maturation and advancement. The PCAD project is jointly managed by Glenn Research Center (GRC) Cleveland Ohio and Johnson Space Center (JSC) in Houston Texas. The architecture of this simple, yet high performance propulsion system is a pressure-fed liquid oxygen and liquid methane system. Both the high performance RCS and main engine are fed liquids and can share common tanks, which enhances uses of the RCS as a translational back-up to the main engine. These features substantially reduce the overall mass and complexity of the system. The PCAD project has specific elements that are exploring all facets of the propulsion system but this paper will focus on the critical enabling reaction control engine (RCE) technologies being developed by the NASA/Aerojet team. The NASA / Aerojet RCS engine enables high overall system performance by being designed to accept cryogenic liquid which eliminates the need to gasify RCS propellants or store RCE propellants separately from main propellants. The cryogenic RCS technology development began with the development of a flight type design and from that design the development challenges were identified and risk reduction efforts were performed by the Aerojet/NASA team. The NASA Aerojet team has conducted testing and will discuss the data which resolves the following 5 major technical challenges of a methane cryogenic RCS which are (1) liquid oxygen (LO2)-rich start transients and chamber burn-through, (2) igniter repeatability and reliable ignition over a large valve inlet temperature regime (liquid-liquid and gas-gas), (3) engine specific impulse / Isp performance, (4) minimum impulse bit (MIB) / pulse-to-pulse repeatability and (5) operability of RCE engines at mixture ratios over 3.0 for operational main engine redundancy.