Optimization and Characterization of The High Efficiency Pulsed Plasma Thruster SIMP-LEX for the Lunar Mission BW1

Pulsed Plasma Thruster has a potential to perform as primary propulsion for space missions with large DV requirements. However, its introduction as a pratical alternative to chemical thruster has been slow in developing due to its low efficiency and complex physical phenomena tied with energy release and plasma acceleration processes. The aim of this work of thesis is to investigate the causes of such a low efficiency and to offer a partial solution of the problem. In order to attain this goal a new design of the Institute of Space Systems APPT, known as SIMP-LEX, was developed on the basis of a theoretical optimization process, whereby an optimum thrust efficiency can be reached as a function of capacitance, maintaining an unchanged energy level. The studies conducted in the capacitance range between 20 µF and 80 µF , allowed to experimentally confirm the envisaged trend. As result of the new design, the area between electrodes was significantly reduced for the purpose of initial inductance minimization and circuit resistance brought down by choosing a single-plate electrode geometry. Both analytical and experimental results were compared to bear the substantial trustworthiness of the method used. A fixed electrodes configuration of 21 mm heigh, 20 mm width and 20 deg of flare angle was chosen in order to reach the highest value of thrust efficiency in accordance with experimental data ensue from previous test campaigns undertaken at IRS. Furthermore, it was found that a quasi-damped current discharge has a positive relapse on performances, i.e thrust efficiency, impulse bit and life expectancy of capacitors, due to a better coupling of electrical and mechanical plasma proprieties. Results obtained are in good fit with other experimental and analytical outturn found in literature.