Outgassing and High Voltage Breakdown Analysis of the SWOT Mission Ka-Band Radar Interferometer

The Surface Water and Ocean Topography (SWOT) mission is a collaboration between the NASA Jet Propulsion Laboratory and the Centre National D'Etudes Spatiales (CNES). The mission's primary scientific objective is to perform the first global survey of the Earth's entire water surface and is variation over time in unprecedented detail. One of the primary instruments used to accomplish this objective is the Ka-Band Radar Interferometer (KaRIn). The KaRIn instrument operates at high voltage which increases the risk that electrical breakdown and arcing can occur within certain high voltage components of the instrument. Described by Paschen's law, electrical breakdown is not monotonically dependent on pressure and there is an intermediate pressure regime where breakdown is most likely to occur. In testing electrical breakdown events were observed which were attributed to the pressure induced by contamination outgassing. In this work a framework is developed to analyze the pressure induced by outgassing and the breakdown voltage of the high voltage components. This framework is used to analyze various scenarios of depressurization ensuring that the high voltage components are not energized while in the intermediate pressure regime where electrical breakdown is most likely occur. The results from this analysis were used to estimate the time required to wait after a depressurization before powering on the KaRIn instrument. The determined time needed to wait to power the instrument without the threat of electrical breakdown were implemented in the SWOT mission to ensure it was able to achieve its scientific objectives.