Material Charging Investigations for Solar Orbiter

Solar Orbiter is a mission led by the European Space Agency (ESA) that is dedicated to solar and heliospheric physics. The wide range of temperature that will be seen by the spacecraft’s external materials is a challenge concerning electric charging. Moreover, water ice layer would possibly be formed in-orbit from materials outgassing and/or thruster operation. In this frame and to evaluate the related risks, the charging behavior of a white paint named PCBE and water ice layers was characterized at temperatures ranging from −153 °C to 20 °C. To do so, samples were exposed in our dedicated facility to a large and uniform electron flux ranging from $J_{\mathrm {beam}} = 0.1$ to 10 nA · cm−2 with a monochromatic energy ranging from $E_{\mathrm {beam}} = 5$ to 60 keV. The in situ ice layer elaboration and characterization are detailed. The evolution of the surface potential decays (SPDs) and the extracted layers apparent conductivities were analyzed in function of time and surface potential at each temperature.