N₂O/DME Bipropellant Thruster with Premixer

Abstract

This paper describes the performance of a proposed premixer-type bipropellant thruster using nitrous oxide (N₂O) and dimethyl ether (DME). Conventionally, nitrogen tetroxide and hydrazine are used in thrusters for spacecraft. However, they require gas treatment systems in the ground tests owing to toxicity and reactivity to materials. Hence, we proposed to apply a premixer to N₂O/DME bipropellant thruster to develop a compact and eco-friendly thruster. The bipropellant is neither toxic nor reactive to materials, and require no gas treatment systems in the ground tests. Moreover, N₂O and DME, which are liquefied gases, are stored in liquid form, and are readily mixed with a premixer. A propellant supply system is simplified because they have sufficient vapor pressures for supply using self-pressurization. In this study, we prototyped a 0.4-N class N₂O/DME premixer-type prototype bipropellant thruster using a coil-type premixer with three types of injector. The thruster yields stable combustion with C* efficiency of 81.8 % at O/F=3.5, at which the theoretical specific impulse is the maximum.