Effect of Capacitance on the Performance of a Di-methyl Ether Pulsed Plasma Thruster

Abstract

We have been testing di-methyl ether (DME) as liquid propellant for a coaxial type pulsed plasma thruster (PPT). Liquid-PPTs can set arbitrary amount of ejected propellant at arbitrary timing, avoiding “particulate-emission” and “late-time ablation,” whereas solid propellant PPTs cannot. Additional feeding pressurant would be removed with the help of DME's expedient vapor pressure. We conducted a study to investigate the effect of capacitance on the thrust performance with our prototyped DME-PPT. The result showed that impulse bits increased monotonically with capacitor-stored energy E. In higher range of E, impulse bits Ibit in the case with capacitance C=3 μF was lower than in the case with the other Cs. The maximum Ibit and specific impulse Isp were 102 μNs and 575 s, respectively, at E=13 J (C=6 μF) and a mass shot Δm=18.4 μg in the range conducted in this study C=3–9 μF.