Validation of an adjustable sensitivity inverted pendulum thrust stand with a novel external plasma thruster

The design and testing of a variable sensitivity inverted pendulum thrust stand (VST) has been undertaken at the University of Southampton. The newly designed thrust balance, in a displacing configuration, has been validated via the measurement of thrust levels with a novel External Discharge Plasma Thruster (XPT). Previously, the External Discharge Plasma Thruster (XPT) has been proposed to solve the lifetime and low efficiency problems of low power Hall thrusters. The operational power is below 500W with 25% maximum recorded anode efficiency and the thrust ranges from 2 to 17 mN. It has the potential to extend the lifetime of Hall thrusters and reduce failure rates, as well as decrease thruster head mass by one order of magnitude. The performance characterisations conducted using the VST were replicated against a torsional thrust balance developed by Added Value Solutions (AVS) UK Ltd and the Surrey Space Centre at the University of Surrey vacuum facilities to validate the measurements taken . The new thrust stand has shown to be calibratable to a thrust resolution of 11 µN with a calibration error of <3 % and has currently been tested with simulated thrusts up to 16 mN. However, testing with the XPT is expects to subject the stand to a thrust range of 0.2 – 20 mN. Calibration and test data will be presented and a discussion on the accuracy and validation of this high accuracy thrust stand will be given.