Performance Measurements of a Medium-Current Short-Pulsed Vacuum Arc Thruster

Abstract

A vacuum arc thruster, powered by a pulsed capacitive circuit, was built and its thrust measured using direct and indirect thrust techniques. Experimental values of ion velocity, ion arc current, and erosion rate were measured. Knowledge of the ion current density distribution was used to consider interference and plume distribution effects on thrust. Both methods measured thrust levels within the expected thrust range (20–60 mN per pulse). Impulse bits as small as 10 nNs could be measured by the direct thrust setup. It was also found that at arc currents >500 A, ion flow was reduced, which resulted in lower thrust.