Contamination Control Approach to Mitigating Deposition on Europa Clipper PIMS Instrument

NASA’s Europa Clipper mission aims to conduct detailed reconnaissance of Jupiter’s icy moon Europa and to investigate whether the moon could harbor conditions suitable for life. Europa Clipper carries with it the Plasma Instrument for Magnetic Sounding, or PIMS, which will study the density, temperature, and flow of plasma near Europa. The instrument plays a key role in determining Europa’s ice shell thickness, ocean depth, and conductivity. There is both an Upper PIMS instrument and a Lower PIMS instrument.Radiation induced outgassing testing led by the JPL Contamination Control group indicates that a high level of outgassing is expected from Clipper’s Stamet Coated Kapton blankets in the Jovian radiation environment. A recent change to the Europa Clipper design has led to the Launch Vehicle Adapter (LVA) remaining with Clipper throughout the mission lifetime. This change introduces both a direct contamination source and a contamination reflection point for radiation induced outgassed contamination from Clipper’s thermal blankets to deposit on the Lower PIMS instrument. Free molecular flow analysis performed by the JPL Contamination group showed the expected molecular contamination deposition level on Lower PIMS drastically increases with inclusion of the LVA on Clipper, pushing the deposition on Lower PIMS over the requirement provided by the instrument. The contamination exceedance could significantly impact the science return from the PIMS instrument.A working group was formed with JPL Contamination Control, Mechanical, Materials and Processes, Thermal, and Systems teams to develop mitigations. The primary approach investigated was the implementation of a contamination shield on PIMS to block contamination from transporting to PIMS Lower. Other mitigations investigated include a contamination shield to block contamination from reaching the LVA and blanketing key locations on the spacecraft with a metallic MLI that outgasses less under radiation. The PIMS team was consulted to ensure the approaches did not cause harm to PIMS and to provide final review of the proposed solution. In the end CC analysis showed that with a PIMS shield implemented the flight system will meet PIMS’s End of Life (EOL) requirement for molecular contamination deposition. This approach shows a method by which Contamination Control identifies a contamination concern with a late-breaking spacecraft configuration change and functions with a multi-disciplinary working group to address and mitigate the concern.