Topographic Analysis of Chang’e-4 Landing Site Using Orbital, Descent and Ground Data

Abstract

<p><strong>Abstract.</strong> The Chang’e-4 (CE-4) probe, which includes a lander and a rover, was successfully landed in Von Kármán crater inside the South Pole-Aitken basin on January 3, 2019. Landing site mapping and topographic analyses have been performed at different scales using orbital, descent and ground data to support mission operations and various scientific investigations. We produced a 0.9 m-resolution seamless digital orthophoto map (DOM) mosaic of the CE-4 landing site region covering 51 km × 30 km using 100 Lunar Reconnaissance Orbiter Camera (LROC) Narrow-Angle Camera (NAC) images. Within an area of 3.2 km × 3.0 km of the the DOM around the lander, more than 11,000 craters with diameter greater than 5 m have been identified and measured. A 0.03 m- resolution DOM, which covers an area of 211 m × 187 m, was generated using descent images, and has been used as one of the base maps for overall rover traverse planning. During surface operations, local DEMs with 0.02 m resolution are routinely produced and topographic analysis have been performed at each waypoint using Navcam images and at some locations using Pancam images, to support waypoint-to-waypoint path planning, science target selection and scientific investigations.</p>

Geospatial technologies for Chang’e-3 and Chang’e-4 lunar rover missions

“…The DEM and DOM have been used in topographic characterization (e.g. slop and crater distributions) of CE-3 and CE-4 landing sites (Wu, Hu, and Guo 2014;Di et al 2019b;Di, Liu, and Liu 2019c;Zhao, Li, and Wu 2019). CE-2 orbiter acquired 1.5-m resolution images at the pre-selected CE-3 landing site (40°N~50°N, 18°W 35°W).…”

“…Technical framework of the geospatial technologies and applications in CE-3 and CE-4 missions. clusters and ejecta materials which can be traced back to several craters in the vicinity (Di et al 2019b;Di, Liu, and Liu 2019c). In addition to applications in landing site characterization, this high-resolution DOM, along with CE-2 DOM, has been used as a basemap in lander localization and long-term rover traverse planning (Di, Liu, and Liu 2019a;Liu, Di, Li, 2019).…”

Topographic Mapping of the Moon in the 21st Century: From Hectometer to Millimeter Scales

“…At the Chang'e-3 and Chang'e-4 lading sites, topographic mapping and analyses have been done at meter to millimeter scales using orbital, descent and rover-based images before launch, after landing and during surface operations Wu et al, 2014aWu et al, , 2020Di et al, 2019aDi et al, , 2020. For example, a 4.5 m-resolution DTM and a 1.5 m-resolution DOM of the Chang'e-3 landing site were generated using the 1.5 mresolution stereo images acquired by Chang'e-2 and used to support topographic analysis of the landing site.…”

“…For example, the topographic mapping products from orbital images are the bases for morphological analyses of lunar landforms, and are critical to support lunar geologic studies. Meanwhile, high-resolution orbital mapping products are particularly important to support landing site evaluation for a lander/rover mission, and also valuable to support lander localization, science target designation, path planning and rover localization (Wu et al, 2014a(Wu et al, , 2020Liu et al, 2015Di et al, 2019aDi et al, , 2020.…”

Properties Analysis of Lunar Regolith at Chang’E-4 Landing Site Based on 3D Velocity Spectrum of Lunar Penetrating Radar

“…SPA basin is the broadest basin on the Moon. This ancient basin was born from asteroid impacts 4 billion years ago, recording the evolutionary history of the far side of the Moon, and is of great significance for researching the internal materials and structures of the Moon [4][5][6]. Von Kármán crater is one of the primary craters in the SPA basin, with a diameter of 186 km.…”