Direct Thrust Measurement of an Electron Cyclotron Resonance Plasma Thruster

Direct thrust measurements of an electron cyclotron resonance plasma thruster are performed with a thrust balance. The thruster performances are deduced, and the influence of power and mass-flow rate is studied. The measured thrust is around 1mN for 50W of microwave power input and 0.1mg/s of xenon, corresponding to 1000s of specific impulse and 11% of total efficiency. It is found that the thrust is increased by 25% when the walls of the plasma source are covered with a dielectric layer. Comparisons are made between the direct thrust measurements and the indirect thrust measurements obtained with electrostatic probes in the plasma beam.