Canadian Electric Propulsion Development: A Cylindrical Hall Thruster

Recent electric propulsion research in the field of Hall Thrusters has developed relatively high thrust efficiencies in the order of 45-55% for large thrusters of half a kilowatt to a few kilowatts. This technology has enabled deep space missions and extended station-keeping capabilities. Although conventional hall thrusters operate efficiently at high power levels, this statement does not hold true when scaling down for a power and volume constrained microsatellite mission. In order to address this issue, the traditional Annular Hall Thruster has been modified to have a cylindrical ionization chamber, thus bearing the name Cylindrical Hall Thruster. The cylindrical ionization chamber configuration decreases plasma wall interactions in the ionization chamber and has been shown to be more efficient in lower power operation. To enable more advanced microsatellite missions, the Space Flight Laboratory (SFL) at the University of Toronto Institute for Aerospace Studies (UTIAS) was contracted by the Canadian Space Agency to develop a low power electric propulsion system compatible with microsatellites. The program lead to the development of a SFL\u27s prototype Cylindrical Hall thruster which has demonstrated the ability to sustain stable operation between 15 - 300 W with an efficiency of 5% - 27% respectively. Test results at the nominal 200 W power level show 6 mN of thrust with a specific impulse of 1140 s using Xenon propellant. The prototype thruster was initially developed to be reconfigurable which allowed the parameters such as propellant flow rate, magnetic field and electric field to be experimentally tuned to find the best configuration. After determining a suitable thruster configuration for stable thruster operation, a refined protoflight thruster has been developed. By using permanent magnets instead of electromagnets, a mass savings of 70% was achieved with a thruster mass of only 450 grams. At 95 mm long and 58 mm in diameter, the thruster was designed to fit in a 1U CubeSat standard volume will be flight qualified to TRL 6. This paper will present and compare the performance results using both Xenon and Argon propellant of the prototype and protoflight thruster