Size, morphology, and composition of lunar samples returned by Chang'E-5 mission

This study focuses on the physical and chemical properties of surficial lunar regolith (LR) samples returned from the Moon by the Chang'E-5 (CE-5) mission. Insights regarding the effect of a new sampling geological site on the surficial lunar sample CE5C0400 were illustrated using nondestructive techniques such as laser diffractometry coupled with image analysis, X-ray computed tomography, and field emission scanning electron microscopy equipped with energy dispersive spectroscopy, and X-ray diffraction combined with Rietveld refinement. From the characterization analyses, the CE-5 sampling site in the northeastern Oceanus Procellarum on the Moon yields a unique collection of relatively regular-shaped and fine basalt-dominated particles. The median grain size D-50 is (55.24 +/- 0.96) mu m, falling within the relatively low end of the range of the Apollo lunar returned samples. The coefficient of uniformity C-u of 15.1 and the coefficient of curvature C-c of 1.7 could classify CE5C0400 to be well-graded. The minerals in CE5C0400 comprise approximately 44.5% pyroxene, 30.4% plagioclase, 3.6% olivine, and 6.0% ilmenite. There is a relatively low content of approximately 15.5% glass phase in the CE-5 lunar sample. From the results, we deduce that the CE-5 LR structure could have mainly resulted from micrometeoroid impacts to achieve such a high level of maturity.