Investigation of a Pulsed Plasma Thruster for Atmospheric Applications

Thesis (Ph.D.)--University of Washington, 2020To date, the controlled access to terrestrial atmospheric altitudes of more than 20 km is limited with current technology. This is because at such altitudes, the background gas density is too low for conventional blade-based propellers to operate, and too high for most in-space electric propulsion systems. This research aims to investigate the Pulsed Plasma Thruster technology for atmospheric applications, at a background gas pressure of less than 50 Torr, corresponding to terrestrial atmospheric altitudes of more than 20 km. Because the system operates in a highly collisional regime, three acceleration mechanisms are identified, 1) due to ion-neutral collisions, 2) due to the JÃ B force, and 3) electrostatic acceleration. A theoretical model to obtain the thrust-to-power ratio of a Pulsed Plasma Thruster for atmospheric applications is presented and validated experimentally using a pendulum-based thrust stand, a quadruple Langmuir probe, and a B-dot probe. A proposed Air-Breathing Pulsed Plasma Thruster was investigated, and based on the experimental results, an analytical approach to determine whether the system can sustain an aircraft at the aforementioned altitudes is presented, and experimentally demonstrated through three in-field tests, consisting on launching in-house designed and built aircraft to the stratosphere using high-altitude burst balloons