Cartography of the Lunokhod-1 landing site and traverse from LRO image and stereo-topographic data

Abstract

We have derived a stereo-topographic model and an orthoimage mosaic based on Lunar Reconnaissance Orbiter (LRO) Narrow Angle Camera (NAC) images to study the Luna-17 landing site. In the images (0.33–0.5m/pixel), the Lunokhod-1, the Luna-17 landed spacecraft, and the rover tracks can clearly be identified and mapped for 99% of the traverse. The traverse was found to be 9.93km long, approximately 0.50km shorter over what had been estimated earlier (10.54km). The total topographic relief along the traverse was found to be within 26m. Along its traverse, the rover encountered slopes of up to 5°, estimated over 2.5m baselength. By comparison with previously published topographic maps and using our orthomosaic as a reference (which had been tied to the well-known Lunokhod-1 Laser reflector coordinates), we report on coordinates of Lunokhod-1's panorama points and overnight stops. Comparisons of currently mapped tracks with previous traverse reconstructions show good matches on small scale, but reveal that previous maps had long-wavelength geometric distortions of up to 100-m level. Agreement in topographic trends was very limited.