Use of Metal Propellants for Spacecraft Plasma Propulsion

This talk will consider the use of metal propellants in Hall Effect Thrusters and other kinds of electric rockets that use plasma for reaction mass. The goal is to present the advantages, challenges in implementation, our understanding of the physics, the state of the art in technology, and thoughts on future engineering and physics-based efforts. What factors make one metal more attractive than another? Emphasis will be placed upon metals that have proven to be feasible in Hall thrusters, such as bismuth, zinc, and magnesium. These substances are typically stored in the solid phase and converted to vapor before ionization and acceleration. The talk will also consider the use of mercury, lithium, cesium, and other metals. The talk will include a discussion of spacecraft interactions, touching upon past measurements taken on the ground and in space, as well as mitigation measures. The talk will also consider in situ resource utilization, and multi-mode propellant applications, with a focus on the potential for magnesium.