Electric propulsion for picosatellites

Abstract

The miniaturisation of technology has found its way to the space industry, giving universities and communities of researchers the opportunity to design their own space systems. This has resulted in many advancements and innovations in space technologies, in particular with nanosatellites (ranging between 1 kg and 10 kg) and picosatellites (ranging between 100 g and 1 kg). However, not all space systems have been scaled equally and some technologies are largely absent in the picosatellite class of spacecraft. One such space system is that of propulsion. Without propulsion, the picosatellite is constrained to its initial orbit set during launch, which limits their range of applications. The limited size of the satellite does not permit for the use of conventional chemical thrusters are too bulky and require unsustainable amounts of fuel. A solution to this problem is electric propulsion, where a small amount of thrust is efficiently generated by ejecting charged particles at very high speeds. Their propellant consumption is exceedingly low making them ideal for mass-constrained spacecraft. The work presented here aims to examine the feasibility of such a thruster for a 1p PocketQube picosatellite, and lay the groundwork allowing for future research. The work is divided into three sections. Firstly, various electrical propulsion technologies are pitted together to find the most suitable engine for the application. The most notable of which is the Pulsed Plasma Thruster, which incorporates the solid propellant, the feeding mechanism and the thruster itself in one compact unit. This is followed by a critical analysis of the Pulsed Plasma Thruster through literature review. Finally, the a number of experiments to examine the behaviour of the thruster in a vacuum environment are conducted. A 10 mm × 15 mm functioning Pulsed Plasma Thruster prototype was achieved. Its power unit generates 2 kV from a 4.2 V source, whilst maintaining a compact size. A number of limitations were imposed on the experiments which lead to some uncertainties. These, together with observations made which require further analysis, are listed to highlight the next steps in achieving electric propulsion for picosatellites.