Study on space weathering of Chang´e-4 landing site by in situ spectra

Without atmosphere, the lunar surface is gradually evolved into lunar soil by the space weathering. The space weathering generates lunar soil and matures it. This progress changes the morphological structure and the spectral characteristics. Thus the spectral characteristics of lunar soil contains information about the space weathering of the moon's surface. Lunar soil maturity is an important indicator to describe the degree of the space weathering. Using hyperspectral data to produce the submicroscopic metallic iron (SMFe) and to obtain lunar maturity is an important method for studying the space weathering. Since the in situ detection data is not disturbed, the results obtained are relatively more accurate and reliable. Therefore, the Chang'e-4 (CE-4) Yutu-2 rover was equipped with a detection instrument that directly obtained the in situ hyperspectral data (450-2395 nm) of the lunar surface, which provided a good opportunity for studying the lunar weathering. Two spectral data near the landing site of the CE-4 lander were selected, using the Hapke model and the spectral angle matching method, SMFe content was produced. The maturity of the lunar soil near the landing site of the CE-4 was further inferred based on the Morris model and FeO content. The results show that the lunar soil's maturity is 11.5, indicating that it may be immature lunar soil.