Mercury‘s polar deposits – origin and evolution

• Applicant: Dr.-Ing. Philipp Gläser
• Subject Area: Geodesy, Photogrammetry, Remote Sensing, Geoinformatics, Cartography
• Term: from 2019 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 434933580

Mercury’s near-zero obliquity and cratered topography create Permanently Shadowed Regions (PSRs) near its poles. It was shown that temperatures in these PSRs are low enough for water-ice to accumulate and be stable. Radar measurements revealed large quantities of radar-bright material which is indicative for, and most likely is, water-ice. Despite Mercury’s proximity to the Sun the amount of radar-bright material is larger than at the Moon. Previous authors have found that, similar to the Moon, all radar-bright material is concentrated within the cold and dark crater floors of PSRs. However, only approximately half of the PSRs seem to contain radar-bright material. It was also found that complex craters (> 10 km) are more likely to contain radar-bright material than simple craters (< 10 km).This study will investigate illumination and thermal conditions near the Hermean polar areas in order to investigate whether the lack of radar-bright material in half of the PSRs might be related to higher temperatures. The thermal study at the north pole will be based on the complete set of measurements from the Mercury Laser Altimeter (MLA) from which a Digital Terrain Model (DTM) of 250 meter per pixel will be compiled using co-registration techniques. Illumination and temperatures will then be simulated based on this DTM. For the Hermean south pole the very first evaluation of the thermal conditions will be carried out in the scope of this study using a new state-of-the-art Mercury Dual Imaging System (MDIS) DTM. The resulting polar illumination and thermal maps will also reveal whether or not the reported difference in measured radar-bright material from simple to complex craters is related to temperature. A detailed illumination and thermal study of Prokofiev crater based on the new DTM is anticipated to conclude the disputed extent of its PSR and whether radar-bright material exists in rarely sunlit surfaces. Maps of illumination, temperature, depth-to-ice and PSRs will be compiled and presented in this study. Based on these maps potential future landing sites near water-bearing PSRs will be found which offer (near-)eternal illumination and hence (almost-)continuous energy supply via solar panels. Last, this study will identify a set of interesting targets which should be observed in more detail in the near future by the BepiColombo spacecraft.

• DFG Programme: Research Grants