Design and Experiments of a HAN-Based Monopropellant Thruster Using Arc-Discharge Assisted Combustion

Abstract

This paper discusses a 1-N class space propulsion thruster using SHP163 monopropellant and arc discharge assisted combustion. SHP163 is a hydroxyl-ammonium nitrate (HAN)-based monopropellant, which has relatively low toxicity and reactivity to materials such as metal and polymers, and can be stored in a liquid form due to its relatively low freezing point. Arc discharge, supporting a SHP163 exothermic chemical reaction, is used as an alternative to conventional particulate catalysts. Part of the pressurant is used as working fluid for the arcjet. Tests using prototyped thrusters show that combustion started and was successfully sustained with the assistance of a 1-kW class arc discharge. Thrust chamber pressure measurements yielded a characteristic exhaust velocity efficiency of 90 %at a specific power of 2.8 MJ/kg.