The Europa Clipper spacecraft’s suite of instruments will be investigating if Jupiter’s moon Europa could harbor conditions suitable for life. Several of these instruments are very sensitive to molecular deposition, whose primary transport is through self-contamination from spacecraft outgassing. The hardware outgassing rate requirements range from 1x10−14 g/cm2/s on the spacecraft exterior to 1x10−12 g/cm2/s inside the Avionics Module, which is significantly lower than previous mission outgassing rate requirements. An effusion cell was developed and implemented in existing thermal vacuum testing facilities at JPL to address the challenge verifying these low hardware outgassing rates. The JPL effusion cell was designed to constrain the transport of outgassed molecules between flight hardware and the Cryogenic Quartz Crystal Microbalances (CQCMs), be compatible with most Europa Clipper hardware, and support outgassing measurement of hardware at Europa operating temperature (50°C to -100°C). The effusion cell improves the fidelity of the CQCM measurement by constraining the test geometry between the flight hardware and the QCM during outgassing rate verification to promote molecular transport of outgassed molecules to the CQCM sensor head. This lowers the sensitivity floor of outgassing rates that can be measured such that the test can verify the low outgassing rate requirements of Europa Clipper. JPL Contamination Control performed tests to characterize the thermal gradient and interior pressure of the effusion cell at Europa operating temperatures. The effusion cell was also modeled in Molflow+ to analyze the transport factor of outgassed molecules to the CQCM sensors. Europa Clipper hardware has verified outgassing rates to the most stringent 1x10−14 g/cm2/s requirement and measured outgassing rates as low as 2x10−15 g/cm2/s using the effusion cell.
Effusion Cell Development, Testing, and Application for Europa Clipper Outgassing Rate Measurements
02.03.2024
3644410 byte
Aufsatz (Konferenz)
Elektronische Ressource
Englisch
NTRS | 2020
|NTRS | 2020
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