Electric Propulsion Diagnostic Package Development and Thruster Characterisation

The present work describes the process of revision and improvement of the micro-Newton thrust balance used by Airbus Defence & Space in Friedrichshafen for electric propulsion testing; in particular, the replacement of the interferometer device used to evaluate the differential translation between the two hanging pendulums of the thrust stand setup. The new device is assembled and the characterization is performed; the necessary hardware modifications are designed and implemented for installation inside the vacuum chamber. The interferometer demonstrated the capacity for differential pathlength measurement, with a noise level under 1 nm/√Hz between 31 mHz and 1 Hz, and the capacity for Differential Wavefront Sensing (DWS) is enhanced from the previous setup. The devices are able to hold an acceptable, and improved, level of contrast when transitioning from in-air to in-vacuum measurements. It is expected that the new setup will improve the performance of the thrust balance apparatus by a substantial amount, and such verification is the natural prosecution of the present work.