The paper presents an aeroheating analysis of a capsule vehicle entering Mars Atmosphere, aimed to support thermal protection system design studies. The capsule configuration is the axisymmetric blunt cone shown in Fig.1. Computational fluid dynamic analyses have been performed to assess the aerothermal environment around the vehicle in order to evaluate the capsule surface heat flux distributions.

The C3NS CIRA code has been used for these computations with a thermo-chemical non equilibrium model suitable for Martian atmosphere. Several numerical computations, both axisymmetric and fully 3D, have been performed in order to obtain heat flux predictions for thermal protection system design scopes. To this purpose, a wide range of flow conditions including reacting and non-reacting flow and different angles of attack have been investigated and compared, both for an elliptic entry and an hyperbolic entry scenario. Moreover, a detailed investigation of non-equilibrium real-gas effects is presented. Some preliminary numerical results are reported in Fig. 1, where the temperature contours together with the stream-traces are shown for a fully 3D computations, considering Mars atmosphere as a perfect gas. For code validation purpose, the available numerical and experimental data of Mars Pathfinder at the entry peak heating conditions have been used. The comparison has shown a good agreement between numerical and experimental data.

EADS Astrium Space Transportation is in charge of the development and manufacturing of the Heatshield for the ExoMars Descent Module.

In the continuation to Mars Express, ExoMars is the first Aurora flagship mission to Mars for ESA. With the aim to bring safely a Rover and a Geophysical and Environmental Package (GEP) to the Martian surface in order to study biological environment, the heatshield is a key element to guarantee mission success.

The reference material for the thermal protection system (TPS) of ExoMars is the Norcoat-Liege, a flight proven cork powder and phenolic resin based ablator.
The paper will present an overview of the background on this material, as well as the development approach to be carried out for its implementation on ExoMars.

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 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.

Martian atmosphere is known for heavy dust storms that can develop within several days and lift aerosol particles up to high altitudes. When planning interplanetary missions to Mars with an atmospheric entry the possibility of being exposed to a dust storm must be considered and TPS must be designed to sustain particle erosion.

In 2001, DLR's L2K facility was upgraded for capabilities in Martian atmosphere. A further upgrade was done in 2005 when a first particle injection system had been developed and installed allowing to perform particle erosion tests on TPS materials. In the frame of ESA's MDUST study and the subsequent DUST study under lead of CNES two test campaigns were performed in L2K to investigate the influence of particle erosion on Norcoat Liege material in Martian atmosphere.

Tests were carried out at several flow conditions imposing different heat loads on the samples. Particle density, particle size and particle flow rate were other test parameters which were varied systematically. Main test results were the samples' erosion data, i.e. mass loss and surface recession, as well as temperatures measured on surface and backside.