Developing a high-fidelity lunar regolith simulant based on Chang'E-5 samples and remote sensing images

The Chang'E-5 (CE-5) mission, China's pioneering endeavor to retrieve lunar samples, brings back approximately 1.7 kg of Moon samples. These CE-5 samples provide valuable material for investigating the properties of lunar regolith and help to understand the geological evolution of the Moon. In this study, we propose a framework for developing a lunar regolith simulant that closely resembles the regolith at the CE-5 landing site. Firstly, the in-situ internal friction angle of the lunar regolith where CE-5 touched down was determined based on the impact depth of the lander footpad and the lunar regolith properties, yielding an estimated range from 29.2° to 43.0°. Secondly, two CE-5 lunar samples, CE5C0300YJFM002GP and CE5C1000YJFM002GP, were analyzed using scanning electron microscopy, micro-computed tomography, and stereoscopic microscopy to investigate particle morphology and size distribution. Thirdly, according to the statistical data from the samples, a new lunar regolith simulant named Tongji University-CE5 (TJ-CE5) was developed through a process involving drying, grinding, sieving, and blending by controlling the bulk density and size distribution. Subsequently, a series of tests were conducted to characterize the properties of the TJ-CE5 simulant. The internal friction angle of TJ-CE5 was measured as 36.9°, which is consistent with the predicted in-situ value. Ultimately, the derived TJ-CE5 simulant is equivalent to the CE-5 lunar regolith in terms of density, particle morphology, particle size distribution, internal friction angle, and chemical composition. Therefore, the framework of this study can be applied to the preparation of other lunar regolith simulants with different properties specific to various landing sites. This research established a methodology for developing a simulant that replicates the characteristics of lunar regolith and provided material for ground experiments supporting lunar exploration and construction missions.