Extending service life of hall thrusters: recent progress and future challenges

Hall thrusters are widely applied to space propulsion missions because of characteristics such as high specific impulse, great thrust-to-power ratio, high efficiency, and simple structure. Because the scope of space missions using Hall thrusters has expanded, a higher total impulse is required to extend a north–south station-keeping mission to an orbit transfer mission, requiring Hall thrusters with improved lifetimes. Existing research shows that improving the anti-sputtering capacity of the discharge channel and significantly reducing the ion energy and flux bombardment on the wall of the discharge channel are the best measures to improve the lifetime of Hall thrusters. This study summarizes the lifetime restraining factors of Hall thrusters and analyzes the magnetic shielding technology, wall-less technology, aft-magnetic technology, and cylindrical Hall thruster technology to reduce ion energy and flux bombardment on the discharge-channel wall, adopting low-sputtering yield materials to reduce the wall erosion rate, which can improve the lifetime of Hall thrusters. This paper also identifies the limitations of each technology, such as the erosion of magnetic poles (MS) and ceramic cover plates (CHT), larger plume divergence angle (wall-less), hard-to-select aft-magnetic degree (aft-magnetic technology), low compactness, and great porosity (graphite material), providing a reference for further research.