Description: Radiation-cooled, bipropellant thrusters are being considered for the Ascent Module main engine of the Altair Lunar Lander. Currently, iridium-lined rhenium combustion chambers are the state-of-the-art for radiatively cooled thrusters. To increase the performance of radiation-cooled engines, improved chamber materials are needed that will allow higher operating temperatures, better resistance to oxidation, and reduce mass. During this effort, an innovative composite thrust chamber is being developed that will incorporate advanced ceramic oxide and iridium liner techniques as well as replacing the expensive, high density rhenium with a low mass carbon-carbon composite. The Phase I results have demonstrated the potential of combining innovative fabrication techniques to produce an advanced ceramic-Ir lined C-C thrust chamber. Hot gas testing has shown the ability of the ceramic oxide coating to reduce the exterior temperature of the C-C jacket, which will enable the use of higher temperature propellants for improved performance. No damage was observed in the ceramic-Ir liner as a result of hot gas testing. During Phase II, the techniques will be optimized to allow fabrication of a 3000 lbf chamber that will be delivered to NASA-MSFC for hot-fire testing.

Benefits: Both government and commercial entities in the following sectors use advanced high-temperature materials for the following applications: coatings, defense, material R&D, nuclear power, aerospace, propulsion, automotive, electronics, crystal growth, and medical. PPI's targeted commercial applications include net-shape fabrication of refractory and platinum group metals for rocket nozzles, crucibles, heat pipes, and propulsion subcomponents; and advanced coating systems for x-ray targets, sputtering targets, turbines, rocket engines, wear and thermal/electrical insulation.

PPI's targeted NASA application is for the Altair Ascent Module main engine. Other NASA applications include in-space propulsion components for apogee insertion, attitude control, orbit maintenance, repositioning of satellites/spacecraft, reaction control systems, and descent/ascent engines, nuclear power/propulsion, oxygen generators, and lunar regolith processing.