Design and performance of a 1 J ablative pulsed plasma thruster fed with non-volatile liquid propellant

In response to demands of the smallest satellites like CubeSats a breadboard model of 1 J-class ablative pulsed plasma thruster supplied with polymeric liquid nonvolatile propellant (perfluoropolyether - PFPE) was designed and evaluated. Design of discharge electrodes was guided by physical model (slug model) whereas battery design was optimized by selecting geometry with minimal inductance to maximize discharge current. Performance was assessed experimentally for different discharge voltages or hardware parameters, and compared with that of a twin-like thruster version operated with solid propellant (PTFE/Teflon). Due to the method of fuel distribution, the shot-to-shot variability of the discharge was significantly reduced for PFPE, resulting in a more stable production of impulse bits. The thrust-to-power ratio (18 mu N/W), specific impulse (400 s) and thruster efficiency (3.5%) of the PFPE-fueled thruster were similar to those of other pulsed plasma thrusters operated with PTFE. They were, however, significantly smaller than the values reported for the seminal L mu PPT project - explanation for this discrepancy is given.