Sputter-Resistant Materials for Electric Propulsion

This SBIR Phase 1 project shall develop sputter-resistant materials for use in electric propulsion test facilities and for plume shields on spacecraft using electric thrusters. A critical need arises because NASA is developing higher impulse, higher power thrusters for deep space science missions. Such thrusters will erode chamber walls ten-times more aggressively than before and create unacceptably high levels of contamination in the life test facilities. Without new materials that are ten-times more resistant than graphite, the only alternative may be installation of larger vacuum test chambers at huge facility cost. The proposed sputter-resistant materials are based on carbon fibers in a highly textured configuration that allows deep penetration of incident ions and trapping of sputtered secondary atoms. Preliminary analysis predicts low sputter yield and significantly reduced backflow suitable for extending the use of existing test facilities to the next generation of ion engines. Refractory, vacuum compatible materials are used. Phase 1 will assess requirements and analyze performance of the concept liner designs. Selected configurations will be fabricated and sputter tested for model validation. Sputter resistant materials designs and Phase 2 development will be reported.