Internal charging modelling of the AMBER instrument on-board Jason-3 spacecraft

Abstract: Internal charging is the accumulation of charged particles inside a material. Thisbuild up represents a serious hazard to satellites and instruments exposed to thespace environment. The Van Allen radiation belts constitute one of the worst spaceenvironments for satellites orbiting the earth. The energy of the electrons is higherthan in any earth orbit. Previous studies have noted the risk of internal charging in alow earth orbit or in geostationary orbit.The internal charging analysis of the AMBER instrument has been performed in amedium earth orbit. To run a relevant internal charging study, a whole dedicatedmodelling chain has been conducted. The instrument has been modelled with thecomputer-aided design software EDGE. The radiation transport analysis has beenperformed with the ESA/GRAS Monte Carlo-based software. The proper internalcharging analysis has been performed with the SPIS-IC software.Depending on various factors such as materials and shielding, the AMBER instrumentpresents few risks of electrostatic discharge. A wrong use of material can represent ahuge hazard in terms of internal charging. A thick shielding can lead to a higher riskof accumulation of charges due to a lower radiation induced conductivity.