DESIGN AND TESTING OF A MICRO HALL EFFECT THRUSTER PROTOTYPE FOR NANOSATELLITES

Abstract

There are two types of spacecraft propulsion commonly used today, chemical and electrical. Hall effect thrusters are a type of electric propulsion with certain advantages over traditional chemical propulsion. This thesis outlines the preliminary steps in the design and development of a micro-propulsion thruster designed for use on a CubeSat platform. These nano-satellites only require milli-newtons of thrust to perform key life-extending maneuvers such as orbit raising and attitude control. A range of existing spacecraft propulsion concepts were considered. Micro Hall effect thrusters were identified as a promising concept. Krypton was selected as the propellant as it offered significant cost savings and similar performance to other gases. The use of a permanent magnet and a cylindrical configuration were deemed most suitable and simulated with a particle-incell code. Using a combination of scaling laws and numerical simulation, a 10mm, 20W Hall effect thruster was designed. This thesis discusses the designed diameter, power, fabrication, and testing campaign of the thruster. Using a torsional thrust stand at the RMC Advanced Propulsion and Plasma Exploration Laboratory, the thrust was measured. The thrust stand fits within a vacuum chamber used to replicate some of the low pressure conditions experienced in orbit. Two configurations were explored with a hot filament cathode and with a hollow cathode. While a thrust was measured using the hot filament, the power required to heat the filament was considerable and led to a low efficiency. Increased success was achieved with the hollow cathode, however, due to high flow rates and laboratory equipment limits, the total efficiency of the thruster was limited. Despite these challenges, a micro Hall effect thruster was demonstrated for further development for a nanosatellite bus with a maximum power less than 100W and 2-5mN of thrust.

Les propulseurs `a effet Hall sont un type de propulsion ´electrique pr´esentant certains avantages par rapport `a la propulsion chimique traditionnelle. Cette th`ese d´ecrit les premi`eres ´etapes de la conception et du d´eveloppement d’un propulseur de micro propul- sion con¸cu `a ˆetre utilis´e sur une petite plateforme. Ces nanosatellites n’ont besoin que de quelques millinewtons de pouss´ee pour effectuer des manœuvres cl´es de prolongation de la dur´ee de vie, telles que l’´el´evation de l’orbite et le contrˆole d’attitude. Les propulseurs `a micro-effet Hall utilisant du Krypton ont ´et´e identifi´es comme un concept prometteur. L’utilisation d’un aimant permanent et d’une configuration cylindrique a ´et´e jug´ee la plus appropri´ee et simul´ee `a l’aide d’une m´ethode particulaire. En utilisant une combinaison de lois d’´echelle et de simulations num´eriques, un propulseur a effet Hall de 10 mm et 20 W a ´et´e con¸cu. Cette th`ese revient sur la conception du propulseur, sa fabrication et sa caract´erisation. La force de pouss´ee a ´et´e mesur´ee dans des conditions de basse pression. Deux configurations du micro propulseur `a effet Hall ont ´et´e explor´ees `a l’aide d’une source d’´electrons `a filament et d’une cathode creuse. Un succ`es accru a ´et´e obtenu avec la cathode creuse, mais en raison des d´ebits ´elev´es et des limites de l´´equipement de laboratoire, l’efficacit´e totale du propulseur ´etait limit´ee. Malgr´e ces d´efis, un micropropulseur `a effet Hall a ´et´e d´emontr´e en vue d’un d´eveloppement ult´erieur pour un nanosatellite