High-Resolution Lunar Topography From Laser Ranging and Photographic Data

Abstract

Mapping landforms on the Moon is of great interest and importance for future human settlements and resources exploration. One of the first steps is to map the topography and investigate their shape and geometry in great detail and resolution, which would provide the first conditions for assessing their suitability for future on-site analysis. However, data from the Lunar Orbiter Laser Altimeter (LOLA) provide low resolution elevation maps in comparison to the size of detailed geological features. To improve resolution, we developed an inverse method to upscale topographic maps to a higher resolution using photographic data from the Lunar Reconnaissance Orbiter Camera (LROC). The method, which exploits the relation between topographic gradients and degrees of shading of incoming sunlight, shows an improvement from ˜60 metres per pixel to 0.9 metres per pixel, bringing it to the same resolution as the optical images from LROC. Our method can detect craters as small as ˜3 metres of diameter and, if illumination from several angles are available, is potentially a way to remove shades from complex features such as caves. It is also possible to estimate the error of the model due to uncertainties in the albedo.