Francois Forget

Atmospheric hazards for entry, descent and landing of future missions to Mars: numerical simulations of fine-scale meteorological phenomena

In order to allow safe entry descent and landing, as well as mission surface operations, constraints apply to the selection of suitable landing sites. These constraints are defined in terms of general characteristics related to the specific mission profile (interplanetary transfer, waiting orbit injection and orbital waiting period and eclipse mitigation strategies) and to the EDL operations (entry conditions and environment, safe operation of the descent system with parachute deceleration, controlled rockets braking, touchdown with vented airbags). Most constraints are relative to « static » properties such as the geographical location, the altimetry, and the soil thermophysical constants. Few constraints are relative to the « dynamical » properties of the atmosphere, i.e. meteorological variations of density, temperature and winds, notwithstanding these are the most crucial characteristics to predict so as to ensure the success of the EDL phase. Martian mesoscale and microscale meteorological models are one of the relevant tools that can be used to predict the local and regional meteorological variability likely to be encountered at several proposed landing ellipses during Entry, Descent, and Landing. Most of the atmospheric hazards in the Martian lower atmosphere are not evident in current observational data and general circulation model simulations and can only be ascertained through mesoscale modeling of the region. The Laboratoire de Meteorologie Dynamique (LMD) Mesoscale Model is a versatile simulator of the Martian atmosphere and environment at horizontal scales ranging from hundreds of kilometers to tens of meters. Specific simulations with relevancy to assessment of atmospheric hazards possibly encountered in Martian landing sites can be carried out with such a tool. The need for accurate and realistic Martian mesoscale modeling remains critical for the design of upcoming missions to Mars (e.g., Mars Science Laboratory, ExoMars).