Characterization of Krypton Ion Sputtering of Spacecraft Materials Using Electric Propulsion

Xenon is the standard propellant in electric propulsion (EP) systems due to its favorable atomic mass and ionization characteristics. However, krypton is gaining interest as a cost-effective alternative, offering a comparable specific impulse at a significantly lower cost. While promising, krypton's long-term effects on spacecraft materials, particularly regarding ion-induced sputtering, remain insufficiently characterized. This study explores the sputtering behavior of krypton ions on materials commonly used on or in spacecraft, including anodized aluminum, boron nitride ceramic, polyimide (Kapton), and glass. These materials are particularly susceptible to erosion from EP plume exposure during extended missions. Test samples are subjected to krypton ion bombardment under varying conditions, including ion incidence angle, exposure duration, and applied voltages. Total sputter yield is quantified using high-precision mass measurements and optical surface profilometry. Additionally, sputtered particles are collected on silicon substrates to assess the differential sputter yield and map the angular distribution of plume material. This way the plume distribution can be characterized. Measurement of the differential sputter yield provides information on how equipment and instrumentation can become contaminated by EP propulsion. Elemental analysis of these deposits is conducted via laser-induced breakdown spectroscopy (LIBS). All samples are preconditioned in low vacuum and weighed prior to testing, with post-test analysis focusing on material degradation and surface morphology. The aim of this research is to assess the long-term effects of krypton-based EP systems on spacecraft material performance, thereby supporting the development of more robust, efficient, and cost-effective propulsion technologies for future missions