Electric Rocket Engine System R&D

1. Pulsed Plasma Thruster Pulsed plasma thrusters (PPTs) are expected to be used as a thruster for a small satellite. The PPT has some features superior to other kinds of electric propulsion. It has no sealing part, simple structure and high reliability, which are benefits of using a solid propellant, mainly Teflon (poly-tetrafluoroethylene: PTFE). However, performances of PPTs are generally low compared with other electric thrusters. At Osaka Institute of Technology, the PPT has been studied in order to understand physical phenomena and improve thrust performances with both experiments and numerical simulations. We mainly studied electrothermal-acceleration-type PPTs, which generally had higher thrust-to-power ratios (impulse bit per unit initial energy stored in capacitors) and higher thrust efficiencies than electromagnetic-acceleration-type PPTs. Although the electrothermal PPT has lower specific impulse than the electromagnetic PPT, the low specific impulse is not a significant problem as long as the PPT uses solid propellant, because there is no tank nor valve for liquid or gas which would be a large weight proportion of a thruster system. This article mainly presents studies on the recent R&D of the electrothermal PPT onboard PROITERES satellite.