Topographic modeling and analysis of the landing site of ChangʹE-3 on the Moon

The Chinese lunar probe ChangʹE-3, carrying the “Jade Rabbit” lunar rover, successfully landed in the Sinus Iridum area on the Moon on December 14, 2013. This paper presents the characterization activities that were done for the selection of the landing area, including topographic modeling and analysis based on multisource lunar remote sensing data. Seven meter-resolution ChangʹE-2 imagery and Lunar Orbiter Laser Altimeter data were integrated to generate a digital elevation model (DEM) with a resolution of 20 m for the entire Sinus Iridum landing area. Long baseline slopes were assessed according to this DEM for all of this area. Lunar Reconnaissance Orbiter narrow-angle camera images and 1.5 m-resolution ChangʹE-2 imagery were used to derive DEMs with higher resolution (4 m) at several local regions within the Sinus Iridum landing area. Slope analyses at lander footprint scale ( ∼ 8   m ) were performed in these local regions. Craters were detected from the DEMs and the derived orthophotos, and size-frequency distributions were generated. Crater morphological statistics, including the depth/diameter ratios, rim height/diameter ratios and wall slopes, were analyzed. The results showed that the Sinus Iridum landing area is relatively flat. Most of the area has slopes of less than 15°. The steeper slopes are mainly alongside craters and ridges. The crater size-frequency distribution is close to the equilibrium distribution. The crater ages, as indicated by their morphological statistics, vary from mature to relatively fresh in different regions. These topographic modeling and analysis results were used for strategic planning to identify the landing site for the ChangʹE-3 and made a useful contribution to the success of the ChangʹE-3 mission.