Performance of MEMS-Based Monopropellant Microthruster With Insulating Effect

Excessive heat loss in micro scale has been a long-lasting issue, affecting catalyst reactivity particularly for monopropellant thrusters and causing insufficient propellant decomposition. Various MEMS fabrication substrates and technologies were utilized for micro propulsion, but few studies on MEMS-based propulsion have reported their propulsion performance, due to not only insufficient propellant decomposition, but also difficulties of measuring high temperature and pressure in a micro scale chamber. In this work, a microthruster was fabricated using high insulation material (glass) in an optical lithography process of photosensitive glass to suppress heat loss. Chamber temperature and pressure sensing tips were integrated in a MEMS fabrication process, which were essential to evaluating propulsion performance and gaining an understanding of the insulating effects of the material on micro propulsion performance. Experimental test results showed successful propellant decomposition with 78% temperature efficiency, which is one of the highest temperature efficiencies in MEMS-based micro propulsion studies reported. The use of glass as a MEMS fabrication substrate was evaluated favorably through numerical analysis as well, in terms of suppression of thermal energy loss and superior propulsion performance.