Characteristics of a Pulsed Plasma Thruster Using Dimethyl Ether as Liquid Propellant

A pulsed plasma thruster (PPT) has attracted attention as a micro thruster because of its compactness, light weight and reliability with digital control features. The conventional solid propellant Teflon PPT, however, has relatively low thrust efficiency and specific impulse among electric propulsion devices because the consumed propellant produces thrust inefficiently owing to late-time ablation or particle emission. To overcome the difficulty in the conventional PPT, liquid propellant PPTs (LP-PPTs) using water or ethanol were proposed, but they require temperature and pressure control system for propellant supply. We hence propose a PPT to use dimethyl ether (DME-PPT) as propellant. DME remains liquid in space and requires no pressurization for feeding propellant because it has a suitable freezing point and vapor pressure. We conducted experiments with a prototyped DME-PPT on thrust performance changing the capacitor stored energy E up to 39 J. The results showed that in the range conducted impulse bits increased monotonically with E and that the maximum impulse bit and specific impulse were 640 μNs and 3540 s, respectively, at E = 39 J and a mass shot ∆m = 18 μg.