Performance evaluation of the Russian SPT-100 thruster at NASA LeRC

TLDR

The study measured the performance of a Russian flight‑model SPT‑100 thruster to evaluate engineering issues for integration with Western spacecraft. The thruster was powered by a US laboratory power conditioner, operated for 148 h with both cathodes, and tested over 3–5 A and 200–300 V (centered at 1.35 kW, 4.5 A) while varying chamber pressure by xenon injection to study pressure effects. Higher facility pressure degraded thruster performance and stability, causing frequent current instabilities that grew over time, while stable operation matched prior Russian laboratory results.

Abstract

Performance measurements of a Russian flight-model SPT-100 thruster were obtained as part of a comprehensive program to evaluate engineering issues pertinent to integration with Western spacecraft. Power processing was provided by a US Government developed laboratory power conditioner. When received the thruster had been subjected to only a few hours of acceptance testing by the manufacturer. Accumulated operating time during this study totalled 148 h and included operation of both cathodes. Cathode flow fraction was controlled both manually and using the flow splitter contained within the supplied xenon flow controller. Data were obtained at current levels ranging from 3 A to 5 A and thruster voltages ranging from 200 V to 300 V. Testing centered on the design power of 1.35 kW with a discharge current of 4.5 A. The effects of facility pressure on thruster operation were examined by varying the pressure via injection of xenon into the vacuum chamber. The facility pressure had a significant effect on thruster performance and stability at the conditions tested. Periods of current instabilities were noted throughout the testing period and became more frequent as testing progressed. Performance during periods of stability agreed with previous data obtained in Russian laboratories.