Highlights• LOLA acquired nearly 7 billion altimetric measurements of the Moon.• The LOLA-defined shape and reference frame enables accurate (<10m) geolocation globally. • The LOLA datasets, including topography, slope, roughness, and reflectance, supports geological and geomorphic studies of the lunar crust. • The high-resolution polar LOLA maps identified areas in permanent shadow and enable accurate illumination modeling. • Active and passive radiometry data were analyzed to inform surface composition and volatile distribution.

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In this study we present a model to determine surface and sub-surface temperatures of airless bodies in the solar system. To precisely model direct sunlight we incorporated the solar limb darkening effect of the solar disk. Scattered sunlight and thermal re-radiation from nearby planets is also considered in our model. We further consider multiple scattering of reflected sunlight and thermal re-radiation on the modeled object itself. The finite volume method is applied to solve the model for which we present full derivations for the governing equations that control scattering and heat diffusion into the sub-surface. We assessed errors stemming from the chosen discretization of the depth profile, the window size from which scattering is considered, as well as from the chosen integration step-size and the spatial resolution of the Digital Terrain Model (DTM). Exemplarily, we determine surface and sub-surface (2 m depth) temperatures for the lunar polar areas. Topography of the lunar poles is modeled by measurements of the Lunar Orbiter Laser Altimeter (LOLA). We integrated temperatures over a 18.6-year time frame using 180 m pixel−1 LOLA DTMs of the poles, a 60 × 60 km window, and a 12 h integration time-step. The resulting preliminary temperature maps for the lunar poles are presented. Further, we show that our model agrees with temperatures obtained by the Diviner lunar radiometer experiment.

We produced 400 x 400 km Digital Terrain Models (DTMs) of the lunar poles from Lunar Orbiter Laser Altimeter (LOLA) ranging measurements. To achieve consistent, high-resolution DTMs of 20 m/pixel the individual ranging profiles were adjusted to remove small track-to-track offsets. We used these LOLA-DTMs to simulate illumination conditions at surface level for 50 x 50 km regions centered on the poles. Illumination was derived in one-hour increments from 01 January, 2017 to 01 January, 2037 to cover the lunar precessional cycle of 18.6 years and to determine illumination conditions over several future mission cycles. We identified three regions receiving high levels of illumination at each pole, e.g. the equator-facing crater rims of Hinshelwood, Peary and Whipple for the north pole and the rim of Shackleton crater, and two locations on a ridge between Shackleton and de Gerlache crater for the south pole. Their average illumination levels range from 69.5% to 82.9%, with the highest illumination levels found at the north pole on the rim of Whipple crater. A more detailed study was carried out for these sites as targets for a lander and/or rover equipped with solar arrays. For this purpose we assumed a lander with a structural height of two meters above the ground (height of the solar panels). Here average illumination levels range from 77.1% to 88.0%, with the maximum found at the ridge between Shackleton and de Gerlache crater on the south pole. Distances, sizes and slopes of nearby Permanently Shadowed Regions (PSRs) as a prime science target were also assessed in this case.

We have derived algorithms and techniques to precisely co-register laser altimeter profiles with gridded Digital Terrain Models (DTMs), typically derived from stereo images. The algorithm consists of an initial grid search followed by a least-squares matching and yields the translation parameters at sub-pixel level needed to align the DTM and the laser profiles in 3D space. This software tool was primarily developed and tested for co-registration of laser profiles from the Lunar Orbiter Laser Altimeter (LOLA) with DTMs derived from the Lunar Reconnaissance Orbiter (LRO) Narrow Angle Camera (NAC) stereo images. Data sets can be co-registered with positional accuracy between 0.13 m and several meters depending on the pixel resolution and amount of laser shots, where rough surfaces typically result in more accurate co-registrations. Residual heights of the data sets are as small as 0.18 m. The software can be used to identify instrument misalignment, orbit errors, pointing jitter, or problems associated with reference frames being used. Also, assessments of DTM effective resolutions can be obtained. From the correct position between the two data sets, comparisons of surface morphology and roughness can be made at laser footprint-or DTM pixel-level. The precise co-registration allows us to carry out joint analysis of the data sets and ultimately to derive merged high-quality data products. Examples of matching other planetary data sets, like LOLA with LRO Wide Angle Camera (WAC) DTMs or Mars Orbiter Laser Altimeter (MOLA) with stereo models from the High Resolution Stereo Camera (HRSC) as well as Mercury Laser Altimeter (MLA) with Mercury Dual Imaging System (MDIS) are shown to demonstrate the broad science applications of the software tool.