Design and Experiments of a Pulsed Plasma Thruster (PPT) Using Liquid Propellants.

Abstract

A Pulsed Plasma Thruster (PPT) is one of the most attractive propulsion devices for stationkeeping, attitude control and main thrusters of small satellites, because it is compact and light. On the other hand, thrust effi- ciency is generally low among electric propulsion systems, mainly owing to poor propellant utilization. In this study, a Liquid Propellant PPT (LP-PPT) is designed to develop a microthruster that controls mass flow rate to enhance thrust efficiency. Liquid is suitable for propellant, since a LP-PPT would be more compact and lighter than a PPT with gas propellant, which requires a high-pressure reservoir. A LP-PPT has an intermittent injector to supply liquid propellant to an interelectrode region. A PPT with pulsed feeding of liquid propellant has never been studied. With a designed thruster, it was checked that discharge is initiated with methanol propellant of 3.9µg at a capacitor stored energy of 13.5 J. Thrust-stand measurements yield an impulse bit of 57µNs, corresponding to a specific impulse of 1500 seconds and a thrust efficiency of 3.1%.