Scenarios for shallow ground ice deposits in Gusev crater

Abstract

Gusev Crater has always been an exciting location for several reasons. It has been suggested that Gusev Crater is the location of a paleolake fed by Ma’adim Vallis, a 900km long fluvial system. Recent results from the GRS instrument on Mars Odyssey indicate an enrichment in Hydrogen in the soil in the region around Gusev Crater, possibly indicating ground ice deposits within the upper 2m below the surface. With the landing of MER Spirit in Gusev Crater we have a unique opportunity to study this place. Unfortunately the rover carries no equipment to study the surface below a depth of a few centimeter and is therefore not capable of exploring even shallow ground ice deposits below a depth of 30cm. We will present some results of our modeling for the longtime stability of near surface ground ice deposits using the BMST (Berlin Mars near Surface Thermal model). This model has already been applied to the Beagle 2 landing site and to one of the MER backup landing sites in Isidis Planitia. MER Spirit will provide excellent data for the thermal and physical properties of the surface material. For this reason we have studied several scenarios varying these parameters over a wide range. We have identified scenarios in which ground ice deposits within 2m below the surface could have been stable over extended periods over time, possibly up to the present time. The comparison with MER Spirit measurements will show which of these scenarios are likely. Should the possibility of shallow ice deposits in Gusev Crater remain, this area would be an ideal landing site for a possible future drilling mission.