Pratt & Whitney Rocketdyne is currently developing an 800 lbf LOX/LCH4 upper stage engine for commercial nanosatellite launch capability. The nozzle extension has an inlet plane diameter of 8", an exit plane diameter of 10.5", and an axial length of 11",. The propulsion system is optimized for cost and weight, with the carbon-carbon nozzle extension offering a significant weight and schedule savings versus traditional, thin-wall metallic designs. The fabrication of the design is rather simple and was focused on lightweight attachment mechanisms that were readily producible, in this case, direct bolting into a single-use ablative thrust chamber. As with other upper stage or exoatmospheric engines, the nozzle extension was designed to run in a radiation-cooled mode only, thereby benefiting directly from the superb operating temperatures offered by carbon-carbon. Additional benefits of a successful Phase 2 SBIR will be to demonstrate scale-up of ACC High Melt for non-engine applications. These applications include structural TPS for aircraft that require multiple uses at temperatures in excess of 2800o
F. This need exists at both NASA and the Department of Defense for hypersonic space plane applications There are a variety of NASA programmatic needs for advanced combustion devices, notably nozzle extensions for upper and exo-atmospheric operation that benefit from the unique materials properties offered by the ACC High Melt material system. A partial list of NASA programs that would derive benefit are robotic lunar or Mars missions like Project M, human lunar ascent, and J-2X. Additionally, ACC High Melt is a material system that can be used as a structural, re-usable TPS system for future spacecraft. The continued development of this material for nozzle extensions will lead to a more in depth understanding of the manufacturability and structural properties that can be applied to the TPS designs of future spacecraft.