Fundamental Characteristics of a Laser Ablation Microthruster

Abstract

The fundamental characteristics of a laser ablation microthruster were investigated for a 10 kg-class microspacecraft. A single-shot impulse measurement was performed using a thrust stand on which a prototype thruster was installed and the associate ablated mass was estimated from the pressure increase in the space chamber. The best performance of several polymer materials was obtained using polyvinylchloride as the propellant. More heavily carbon doped polyvinylchloride showed higher performance, which means absorption length has a large effect on performance. The intensity of the laser beam on the ablation material was changed using constant laser power, and it was shown that intensity had little effect on the performance. This qualitative behavior agreed with the results of a simple thermal analysis. Mass spectroscopy of the ablation plume showed that the dominant reaction was dehydrochlorination in the range of 470 to 640 K, and the low-temperature reaction resulted in the best performance for polyvinylchloride.