Analysis of Chang’e-5 lunar core drilling process

Chang’e-5 explorer successfully acquired lunar regolith core samples from depths of greater than 1 m of lunar surface.This study analyzed the lunar core drilling process based on the telemetry data,image information,and returned samples to optimize the sampling device design and enhance the understanding of the lunar regolith.In particular,a prediction method for the projected drilling path and local terrain fitting of drilling dip angle was proposed based on the flight events recorded during the core drilling process and the image information acquired before,during,and after sampling.The results revealed that the drilling dip angle of Chang’e-5 was approximately2.3.,and the deviation of the drilling length and depth was less than 2 mm.For continuous drilling,a fusion method based on telemetry data and image information was applied to determine the demarcation point of drilling with and without the lunar soil.The position of the demarcation point implied that the drilling point remained at approximately 6 mm loose soil,thereby lagging the action of the force response.Additionally,a characteristic parameter comparison method was proposed for the lunar and ground drilling to analyze the status of the lunar soil.Furthermore,the analysis results revealed that the majority of the Chang’e-5 drilling samples were derived from 0–73.8 cm below the lunar surface and few samples were extracted below 73.8 cm,as the drilling encountered several rocky regions.Moreover,the drilling point exhibited two prominent stratification variations at~28.7 cm and~70 cm below the lunar surface.Ultimately,the preliminary relationship between sample dissected position in soft tube and drilling displacement was analyzed.The segmented estimation results can support research on subsurface lunar soil.

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 CE5 C0400 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 Xray 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)μm,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 CE5 C0400 to be well-graded.The minerals in CE5 C0400 comprise approximately 44.5%pyroxene,30.4%plagioclase,3.6%olivine,and6.0%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.