Dust Particle Erosion during Mars Entry. Issue1

The ablator Norcoat Liege is baselined as thermal protection material for the European probe EXOMARS planned to land on Mars in 2016. During some Martian years, for unknown reasons, local dust storms may grow to global encircling storms in only a few days. Accordingly, any probe entering directly from a hyperbolic approach has to cope with the risk of flying in a severely dust loaded atmosphere. The dust layer may extend up to 80 km above the terrain. In the frame of two studies in contract by ESTEC and CNES, particle erosion of Norcoat Liege has been investigated in the years 2005 – 2008. A systematic arc-jet test program has been performed that time, which is currently substantiated by an additional test campaign between in spring 2010, again in contract to CNES. In this paper a summary of the previous activities will be given, the results of the new investigations presented and the estimated influence on heat shield design assessed.