RESEARCH AND DEVELOPMENT OF A CHARGED-PARTICLE BIPOLAR THRUSTER

Research was performed on the generation of charged particles by subjecting a liquid, at the tip of a capillary emitter, to a high electric field. The research was aimed at the ultimate development of a highly efficient microthruster capable of emitting equal currents of positive and negative particles. A specific charge range from 50 to 7 × 105 coul/kg has been obtained using organic solvents with conductive dopants as the propellant fluid. The specific charge and other performance parameters were determined by time-of- flight spectroscopy. A 50- hr life test of a bipolar thruster was successfully completed. Capillary emitter potentials were +4.4 kv and —5.8 kv with average currents of +150 μa and —154 μa. Thruster power was 1.55 w with a power- to- thrust ratio of about 20 w/mlb at measured thrust levels greater than 80 μlb. © 1969 American Institute of Aeronautics and Astronautics, Inc., All rights reserved.