Hybrid rocket development with nytrox blends through real-gas modeling and planned hot-fire testing for in-space applications

Abstract

Hybrid rocket propulsion offers a practical solution for in-space applications by combining simplicity, restart capability, and operational safety. This study investigates the use of thermoplastic fuels with nitrous oxide–based oxidizers, including oxygen-enriched “Nytrox” blends, to improve ignition reliability, regression behaviour, and specific impulse. A laboratory-scale hybrid rocket test stand equipped with a detailed piping and instrumentation diagram (P&ID) has been developed to support hot-fire campaigns across oxidizer preheat temperatures from 30 °C to 90 °C. The campaign will characterise ignition dynamics, steady state thrust, and fuel regression under representative operating conditions. Complementary modelling integrates NASA CEA with the Peng–Robinson equation of state to capture real-gas effects on flame temperature, oxidizer density, and convective heat transfer. Oxygen enrichment is expected to enhance regression rates and overall performance, providing design guidance for compact and mass-efficient hybrid systems suitable for upper stages, orbital manoeuvres, and deep space transport.