Cartography of the Luna-21 landing site and Lunokhod-2 traverse area based on Lunar Reconnaissance Orbiter Camera images and surface archive TV-panoramas

Abstract

Lunar Reconnaissance Orbiter Camera (LROC) system consists of a Wide Angle Camera (WAC) and Narrow Angle Camera (NAC). NAC images (~0.5-1.7 m/pixel) reveal details of the Luna-21 landing site and Lunokhod-2 traverse area. We derived a Digital Elevation Model (DEM) and an orthomosaic for the study region using photogrammetric stereo processing techniques with NAC images. The DEM and mosaic allowed us to analyze the topography and morphology of the landing site area and to map the Lunokhod-2 rover route. The total range of topographic elevation along the traverse was found to be less than 144 m; and the rover encountered slopes of up to 20 degrees. With the orthomosaic tied to the lunar reference frame, derived coordinates of the Lunokhod-2 landing module, its final position and overnight stop points. We identified the exact rover route by following its tracks and determined its total length as 39.16 km, more than was estimated during the mission (37 km), which until recently was a distance record for planetary robotic rovers held for more than 40 years. 126Lunokhod-2 moved at two distinct speeds: 0.8 km/hour and 2.0 km/hour (Kemurdzhian et 127 al., 1993). Turning of the vehicle was achieved by varying the rotation of the wheel on the right 128 and left sides, respectively, and by changing the direction of their rotation. The turning radius of 129 the rover in motion was typically 3 m with wheels turning at different speeds (Kemurdzhian et 130 al., 1993). However, the rover could also turn in place (with its left and right wheels turning in 131 opposite directions) within a radius of 0.8 m. Areas where the rover turned in place can be seen 132 readily in the NAC images. 133

Method of a Planetary Rover Localization Based on Synthetic Lunokhod Images

“…The accuracy of the modelled artificial surface image mostly depends on the input DEM. For example, for Lunokhod-2 region DEM with resolution 1.7 m/px was obtained (Karachevtseva et al, 2016). Relative position of two points in the DEM can be measured to 0.3-0.5 px that corresponds to the accuracy of 0.5-0.8 m. On the other hand, pixel size of the surface image depends on camera parameters and the distance to the object.…”

“…To test the developed technique on original images we selected Lunokhod-2 area. Detailed study of LRO NAC data allowed us to determine Lunokhod rover tracks and refine the route with high accuracy based on created DEM and orthoimage (Karachevtseva et al, 2016). Modern processing of panoramic images (Kozlova et al, 2014) prepared them for further use in this study as original data.…”

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“…4) Анализ строения палеодельт и конусов выноса [Goudge et al, 2017], овражной сети [Conway et al, 2016], миграции дюн [Cardinale et al, 2016;Runyon et al, 2017;Vaz et al, 2017] и эрозионных паттернов [Brusnikin et al, 2016] при изучении флювиальных, эоловых и склоновых процессов на Марсе. 5) Анализ и картографирование мест прошлых и планируемых посадок космических аппаратов [Karachevtseva et al, 2017;Bhardwaj et al, 2019a]. 6) Геоморфологическое картографирование .…”

Special Software for Planetary Image Processing and Research

“…Based on about 60 processed LROC NAC images and 6 stereo pairs were generated 2 DEMs to reconstruct and map the traverses and working areas of the Lunokhod-1 (Karachevtseva et al, 2013) and Lunokhod-2 (Karachevtseva et al, 2016b). These results give us not only new insights into previous missions achievements, but provide support for selection of candidate landing sites of future Russian mission Luna-25 (Luna-Glob) to the Moon south polar area (probably, within crater Boguslawsky).…”