Dust Particle Erosion during Mars Entry

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. In the frame of two studies in contract to ESTEC and CNES, particle erosion of Norcoat Liege has been investigated. A systematic arc-jet test program supported by trajectory and flow field simulations has been performed. In this paper the results of these investigations are summarized and the influence on heat shield design is assessed.