The scope of the thesis is the design and development of a miniaturized high performance chemical bipropellant thruster operated with green propellants for satellite onboard propulsion. Due to increased awareness of environmental hazards such as toxicology and carcinogenicity of currently employed storable space propellants, interest in less toxic alternative propellants has aroused, necessitating the development of thrusters able to be operated with these propellants. The thruster designed and investigated in this thesis bases on highly concentrated hydrogen peroxide as oxidizer, which has drawn renewed attention to its potential ability to replace carcinogenic, hypergolic propellants, reducing production, storage and handling costs, while maintaining high performance. The thruster designed in this work is a miniaturized bipropellant engine in staged configuration, able to autoignite with easy to handle, low toxic fuels such as kerosene and ethanol. The envisioned thrust level makes the thruster a potential candidate for onboard propulsion for both precision attitude control and as orbit maintenance propulsion system for small satellite missions. The target thrust level is one order of magnitude below commercially available bipropellant thrusters to date and competes with available monopropellant thrusters with reduced performance. This miniaturization, while posing inevitable difficulties to a high performance design, makes this thruster a potentially interesting, low cost propulsion option for a large variety of low thrust and precision propulsion applications.
The thruster designed in this work features a staged combustor configuration, in which the liquid oxidizer hydrogen peroxide is heterogeneously decomposed in a dedicated decomposition chamber, generating a high temperature oxygen/steam mixture. This gaseous oxidizer is then injected into the combustion chamber where it is combusted with the additionally injected liquid fuel. Autoignition capability of the thruster is aspired, meaning the ignition of the oxidizer/fuel mixture without external igniter.