Performance Measurements Using a Sub-Micronewton Resolution Thrust Stand

A sub-micronewton level thrust stand is used to evaluate the performance of five different microthrusters. Using a torsional balance design, the JPL microthrust stand (μTS) is capable of measuring steady-state thrust as low as 1 μN with sub-micronewton resolution and an impulse as low as 1 μNs with sub-micronewton-second resolution. The μTS can support a test object with a mass as large as 10 kg while supplying multiple diagnostic, power, and propellant lines to the thruster. The thrust or impulse is measured by monitoring the position of the thrust arm and using a calibrated dynamic model that will be presented in this paper. The performances of a vacuum arc thruster (VAT), gas-fed pulsed plasma thruster (GFPPT), indium field emission electric propulsion thruster (In-FEEP), vaporizing liquid microthruster (VLM), and micro-cold gas thruster have been measured using this test stand to validate its accuracy and precision.