A testbed for the Cathodic Arc aluminum plasma thrusters*

An increased interest in miniature Cathode Arc Metal Plasma Thrusters was prompted by advances in high-power electronics with application to the CubeSat technology, where compact high efficiency thrusters can significantly extend the mission envelope. Two notable examples are George Washington University’s two-electrode with applied magnetic field [1] and Alameda Applied Sciences Corporation’s triple-electrode no field [2] thrusters. Our initial design is like the latter with added ~0.1-0.3T axial magnetic field, which is created by an external electromagnet. The cylindrical cathode, which serves as the main source of propellant, is made of aluminum due to it representing a majority of the approximately 2kT of space debris in LEO. The design of the driving circuit for the thruster and discharge characteristic data are discussed along with other key elements. Spectroscopic measurements show a high degree of ionization in the exhaust, with singly and doubly ionized species being present. Doppler spectroscopy showed ~17km/s exhaust velocity. Data for different regimes are presented and discussed.

[1] M.Keidar, Micro-Cathode Arc Thruster for small satellite propulsion, 2016 IEEE Aerospace Conference, 2016, doi: 10.1109/AERO.2016.7500506.

[2] M.Krishnan, K.Velas, S.Leemans, Metal Plasma Thruster for Small Satellites, J. Prop. Power, Vol. 36, No. 4, 2020, doi: 10.2514/1.B37603