Space Propulsion Group, Inc (SPG) proposes to conduct investigations on Nytrox/paraffin-based hybrid rocket systems which promise high energy flexible propulsion solutions with high volumetric fuel efficiency while retaining the safety and cost advantages of classical hybrids. The benefits of the proposed hybrid concept result from a combination of two key SPG technologies: high-regression rate paraffin-based solid fuels and high performance Nytrox oxidizers which are refrigerated mixtures of nitrous oxide and oxygen. The high regression rate capability simplifies the fuel grain design, minimizes fabrication costs, improves fuel volumetric loading and reduces the fuel sliver mass fraction to less than 3%. The major advantages of Nytrox oxidizers are 1) higher density, Isp performance and safer operation compared to N2O, 2) partial self pressurization, non-cryogenic operation compared to LOX. Nytrox/paraffin based hybrids are ideal for systems that require operational flexibility due to the possibility of active throttling with very small performance penalty, a direct consequence of the relatively flat c*-O/F curve. Phase I work has two major components: 1) propulsion system design/optimization studies with emphasis on mission flexibility and 2) small scale motor testing to demonstrate the throttling and gas phase combustion with gaseous oxygen at the end of the liquid burn.
Keywords: Hybrid Rocket Propulsion, Paraffin-Based Fuels, Nytrox Oxidizers, Operational Flexibility
