Spacecraft Worst Case Surface Charging: On the Importance of Measuring the Electron Emission Yield Under Representative Environmental Conditions

To represent the time spent by space materials on ground before launch, the measurement of secondary electron emission properties is performed after long duration exposure to ambient atmosphere and humidity. The observed change with respect to pristine samples has an impact on the estimation of worst case surface charging levels in geostationary orbit, especially for a spacecraft in eclipse. It is therefore recommended to adequately outgas the samples with respect to the expected flight conditions and aging effects.