Highly Resolved Topography and Illumination at Mercury’s South Pole from MESSENGER MDIS NAC

Abstract

Mercury’s south polar region is of particular interest since Arecibo radar measurements show many high-reflectance regions consistent with ice deposits. However, current elevation information in Mercury’s southern hemisphere is not sufficient to perform detailed modeling of the illumination and thermal conditions at these radar-bright locations and to constrain properties of the volatiles potentially residing there. In this work, we leverage previously existing elevation maps of Mercury’s surface from stereo-photogrammetry at 665 m pix−1, Mercury Dual Imaging System Narrow Angle Camera images, and Shape-from-Shading tools from the Ames Stereo Pipeline, to provide the first high-resolution topographic maps of the south pole with a resolution of 250 m pix−1 poleward of 75°S. We show that the increased resolution and level of detail provided by our new elevation model allow for a more realistic recovery of illumination conditions in Mercury’s south polar region, thus opening the way to future thermal analyses and for the characterization of potential ice and volatile deposits. We compare both the old and new topographic models to the Mercury Dual Imaging System Narrow Angle Camera images to show the higher level of fidelity with our products, and we assess the improved consistency of derived permanently shadowed regions with reflectance measurements by Arecibo’s antennas.

Remote Sensing and Data Analyses on Planetary Topography

“…Despite the strong attraction for constructing higher resolution 3D products without stereo coverage, the validity of 3D reconstruction based on deep learning for planetary research should be carefully investigated before the use of scientific applications, as the referencing of a height plane highly depends on the ground-truth employed, such as LiDAR and stereo DEM and no guarantee to inherit their accuracy into the dimension of far finer resolution. In the case of shape from shading, the validation of products is also strongly required, even with recent successes in extensive 3D reconstruction, as shown in Mercury by Tenthoff et al [226] and Bertone et al [227]. It's because the establishment of a fully working reflectance function on the planetary surface as well as the solution of geodetic control in a single image source are not yet available.…”

Investigating the Stability and Distribution of Surface Ice in Mercury’s Northernmost Craters

“…The Mercury Dual Imaging System (MDIS) captured multispectral images of Mercuryʼs surface, and the Mercury Laser Altimeter (MLA) measured the northern hemisphere topography (Solomon & Anderson 2018). These measurements enabled the derivation of maps of shadowed regions, which showed a considerable overlap with the radar-bright deposits near both poles (Deutsch et al 2016;Chabot et al 2018b;Barker et al 2022;Gläser & Oberst 2022;Bertone et al 2023). Modeling of the thermal conditions using the MLA-determined topography at Mer-curyʼs north polar region revealed that water ice was stable over geologic timescales within many of the permanently shadowed regions (PSRs; Paige et al 2013;Chabot et al 2018a).…”