Computational Investigations of Characteristic Performance Improvements for Subkilogram Laser Micropropulsion

Experimental investigations have evaluated the feasibility of using laser-driven plasma microthrusters for small-thrust, high-specific-impulse space maneuvers, particularly for micro- and nanosatellite missions. Recent work made use of the Mach2 hydromagnetics code for the construction of an adequate computational model of the micro-thruster opera- tion. This thesis expounds on this previous work by extending the computational modeling capabilities, allowing for the determination of plasma plume properties and characteristic performance assessment of the microthruster; this allows for further computational investi- gation of the performance improvements achieved by new design considerations. Two par- ticular design changes are implemented and measured: (i) the simulation of microthruster performance intentionally achieving laser-supported detonation of energetic polymer fuels for higher-thrust capabilities, and (ii) the implementation of an axisymmetric nozzle to improve passive solid-fuel performance. The Mach2 hydromagnetics code with the new performance assessment capabilities was used to examine the performance improvement of these new modes of operation; results of the simulations are presented and then evaluated for their use in the overall design of the plasma microthruster. Laser-supported detona- tion shows a tremendous potential increase in the laser momentum coupling coefficient Cm , and demonstrates a much higher thrust; the axisymmetric nozzle varies with nozzle half-angle and length, but still demonstrates expected nozzle trends and improves the laser momentum coupling coefficient, Cm , by up to 230% for some designs considered.