Magnetron sputtering thruster operated with a compact gas feeding system using double pulsed valves

Abstract

A continuous injection of gaseous water propellant into a magnetron-type sputtering propulsion device is performed in a pseudo manner by using a combination of two high-speed solenoid-type pulsed valves and a low-pressure gas reservoir . The gas injection system provides a temporally averaged gas flow rate of about 5–10 sccm with adjustment of the repetition frequencies of the pulsed valves, while the previously used single valve system attached to a liquid water tank has caused excessive gas injection. A discharge is sustained by a high voltage dc power supply; the discharge current has pulsation synchronized with the pulsed valve repetition. A temporally averaged force induced by the magnetron sputtering thruster and exerted on a pendulum plate downstream of the thruster is measured; the results are in good agreement with the previously reported force measurement under precisely controlled gas flow rate using a commercial mass flow controller. Therefore, the precise control of the gaseous water propellant with the compact gas feeding system is achieved, while maintaining a similar thruster performance to that with the mass flow controller.