Preparation Of Water-bearing Simulated Lunar Soil Based On Cold Trap Trapping Method And Its Micromorphological Characterization

The Lunar Exploration Phase Ⅳ project focuses on the exploration of the lunar polar region and realizes the detection of water ice in the polar region and the extraction of water ice resources and returns to the ground,followed by the verification and investigation of the composition and related parameters,but the physical properties change due to environmental changes,so the ground simulation of water-bearing lunar soil is a prerequisite and guarantee for the investigation of the physical properties of lunar soil water ice and in situ mining.In this paper,we investigate the preparation of water-bearing simulated lunar soil based on cold trap capture method and its microscopic characterization and evaluation.Starting from the formation mechanism of water-ice cold trap capture in the lunar polar region,we analyze the source of lunar water,water preservation mechanism and simulation principles,and further determine the principle of lunar soil simulation based on vapor condensation ice and the four key elements of lunar soil simulation on the ground:temperature environment,vacuum environment,water molecules and particulate matter.By controlling the temperature and vacuum environment to ensure the simulation of outer space environment as well as permanent shadow zone,the mineral composition,particle size distribution and particle size gradation of lunar soil in the polar region are analyzed based on the physical property data of upland lunar soil samples obtained from Apollo series lunar exploration,and the principle and mode of water adsorption are determined based on the source of lunar water.Based on the physical parameters of the lunar exploration high and low lunar soil samples and the particle size distribution,the mineral composition and ratio of the simulated lunar soil are determined,and the base material of the simulated lunar soil is mixed with 0～1mm plagioclase and basalt in the ratio of 7:3.The process is based on the mineral composition of real lunar soil and uses several steps,such as water vapor preconditioning,drying,natural cooling,cold trap preconditioning and trapping,to prepare vapor condensation ice simulated lunar soil.Based on the principle of steam condensation ice simulation moon soil preparation test,the corresponding test equipment and the corresponding parameters of each device are tested and commissioned,the working principle of the whole test bench is analyzed,the simulation conditions and test indexes to be satisfied,the test method and process are briefly described,the results of the steam condensation ice simulation moon soil preparation test are analyzed,the possibility of water molecule transport is illustrated from the phenomena of the prepared multiple samples,and the feasibility and scientificity of the test are further illustrated by correlating each test process with pressure and temperature and from the parameters of pressure and temperature data with the three-phase diagram of water.The mineral color transformation in the absolute drying stage of the vapor condensation ice simulated lunar soil preparation test is analyzed using X-ray diffraction(XRD),the adsorption of the prepared simulated lunar soil water ice samples on the surface of the simulated lunar soil particles and the main microscopic morphological characterization are briefly analyzed,the actual water content of the prepared water-containing simulated lunar soil is examined and compared with the configured water content,and finally the prepared simulated lunar soil is verified using a mathematical model of the ice film thickness.Finally,the simulated lunar soil pressure and the actual ice film thickness are verified using the mathematical model of ice film thickness.