Liquid propellant microthrusters

This chapter covers the development of liquid propellant microthruster for nanosatellites. The historical background and principles of operation of liquid propellant propulsion system were provided, followed by the key aspects of chemical propellants, which are relevant to their implementation in nanosatellites, such as propellant performance, from bipropellant to monopropellants, from macroscale to microscale, and from toxic hydrazine to energetic green propellants. The state-of-the-art systems, ranging from those with flight heritage to those still under development, were featured and elaborated. The coverage is not limited to the traditional hydrazine-based microthrusters or the energetic green propellants (e.g., hydroxylammonium nitrate and ammonium dinitramide)-based microthrusters, but also the other innovative liquid propellant microthrusters (e.g., water electrolysis, hydrogen peroxide/ethanol, nitrous oxide/dimethyl ether, and nitrous oxide/propene). The chapter ends with a discussion on the future and challenges in both monopropellant and bipropellant microthrusters.