Iac-06-c4.p.4.4 Mathematical Modeling of High Effeciency Pulsed Plasma Thrusters for Microsatellites

The Pulsed Plasma Thruster (PPT) is a low cost reliable electric propulsive device that has typical performance within the ranges; specific impulse 300 – 1700 s, Impulse bit 0.06 – 2.6 mN.s and thrust efficiency less than 20%. Past studies have focused on specific aspects to increase performance and understanding, i.e. late time ablation or current sheet canting. Although enlightening, they have yet to increase significantly the efficiency of the PPT. Studies at Surrey Space Centre (SSC) focus on a system design approach to create an efficient PPT. A modified slug parallel plate model published by Worchester Polytechnic Institute, verified with the LES 6, LES 8/9 and Dawgstar PPT data, forms the basis of the SSC optimisation model. The modified model, presented in this paper, works by using a set of coupled differential equations that are solved in MatLab that describe the dynamics of the pulse plasma discharge. Using the SSC optimised model analysis of various thruster parameters leads to the formulation of relationships presented here that describe best-fit curves that can optimise a thruster. This model was used to design a new two stage parallel plate PPT (presented within) which SSC will develop and test, predicting performance within the following ranges; specific impulse 1500 5000 s, Impulse bit 0.3 – 0.8 mN.s and thrust efficiency above 60%.