Mineralogy of Surface Materials at the Chang'E-5 Landing Site and Possible Exotic Sources From In Situ Spectral Observations

Abstract

China's Chang'E-5 (CE-5) mission landed at 43.06°N and 51.92°W on 1 December 2020, within the Northern Oceanus Procellarum region of the Moon. The CE-5 landing site is situated within a young lunar basalt unit estimated to be around 2.0 Ga. A comprehensive understanding of the lunar regolith composition within the CE-5 region is pivotal as it furnishes additional scientific evidence concerning its origin. This, in turn, would further improve our understanding of lunar geology and evolution. In our studies, we employed a variety of spectral data and derived products including the CE-5 Lunar Mineralogical Spectrometer data, the ferrous mineral abundance derived from Kaguya Multiband Imager, and the Chandrayaan-1 Moon Mineralogical Mapper data. These data enabled us to determine and analyze the compositions of the diverse materials present in the CE-5 region and to pinpoint the origins of exotic materials found therein. Our results indicated that the exotic material within the CE-5 region is principally composed of clinopyroxene and plagioclase (Pl). Further analysis unveils that the CE-5 regolith embodies a blend of two distinct varieties of clinopyroxene, designated as Type A and Type B, along with feldspar. This discovery markedly diverges from the conclusions drawn by preceding studies, which relied solely on remote sensing data. Moreover, the exotic materials are predominantly constituted by the ejecta of Harpalus and Aristarchus craters. This finding furnishes a substantial geological background for the analysis of exotic materials in the samples returned by the CE-5 mission in forthcoming studies.