National Aeronautics and Space Administration plans to deploy astronauts to the Moon and construct sustainable habitat modules in collaboration with private companies and national space agencies worldwide. In situ resource utilization (ISRU) is indispensable for large-scale, long-term human lunar exploration. Water ice, which is one of the most precious resources, is believed to exist in the Moon's polar regions. Future plans include using it to maintain life support for astronauts and provide raw materials (H2 and O2) for rocket engines and fuel cells. Because the capture and delivery of ice are required to utilize water on the Moon, the following potentially reliable and efficient capture and delivery technologies for water ice, which are based on electrodynamic, electromagnetic, and mechanical vibration forces, are being developed. (1) The first is a capture and delivery system based on electrodynamic standing waves. When a high alternating voltage is applied to parallel screen electrodes, the alternating electrodynamic force is exerted on ice and regolith particles in contact with the lower electrode, and some agitated particles are captured after they pass through the openings of the upper screen electrode. The captured particles are transported between an array of zigzag electrodes activated by the application of high alternating voltage. (2) The second is a delivery system that utilizes an electrodynamic traveling wave. Three- or four-phase high voltage is applied to parallel line or ring electrodes to form an electrodynamic traveling wave. Meanwhile, regolith and ice particles are conveyed by traveling waves. Horizontal, curved, inclined, and vertical deliveries are realizable using this system. (3) The third is an electromagnetic delivery system based on the coil-gun principle, which considers the fact that lunar regolith particles are magnetic. A multistage coil-gun mechanism powered by a charged inductor-capacitor-resistor (LCR) circuit is used to deliver the regolith particles over long distances. (4) The fourth is a vibration delivery system. The vibration-conveyance mechanism, which is widely applied in terrestrial industries, is used to deliver regolith and ice particles. When the particles are on a plate or in a tube vibrated diagonally by actuators, the vibrating plate or tube is repeatedly propelled and conveys the particles diagonally in the forward direction. When the lower end of an inclined or vertically supported vibrating tube is immersed in a layer of regolith or ice particles, particles are introduced into the tube, and the friction force between the particles and the inner wall of the tube is used to convey the particles upward. This paper provides an overview of the recent progress of these unique technologies for efficient and reliable ISRU on the Moon.

Lunar water ice resources are important space assets for human survival and sustainable living on the Moon. Detection data indicates that the permanently shadowed regions at the lunar poles contain water ice resources. The efficiency of in-situ extraction of lunar water ice resources depends on its volatile characteristics. In the context of extraction and utilization of water ice resources in the permanently shadowed regions, the sublimation and diffusion processes of lunar water ice are investigated by combining the theory of pure ice sublimation with the fractal theory of porous media. On this basis, a volatilization model for lunar water ice is established to examine the effect of temperature, relative density, and water content on the volatile behaviors of lunar water ice. The findings of this study can provide technical and theoretical support for the in-situ exploration, extraction, and utilization of lunar water ice resources and offer insights into the existence and distribution of lunar water ice resources.

Understanding the mechanical response of a high -speed penetrator penetrating icy lunar regolith (ILR) is essential for designing penetrators in lunar permanently shadowed regions and interpreting the detection data from the device. Experimental research on the penetrators is limited in engineering due to the difficulties in preparing large-scale icy lunar regolith simulants (ILRS). Such limitation urges the need to construct a theoretical model and verify a numerical simulation model based on the scaled-down penetration experimental results, which provide insights into the mechanical response of penetrator penetrating ILR. Projectile penetration experiments were conducted on ILRS targets with four typical water content levels in a cryogenic chamber at 110 K. The experimental results show that the ILRS with higher water content exhibits greater brittleness and a faster crack growth rate. Consequently, the diameters of cratering and scabbing areas are augmented on the target surface upon projectile penetration. Moreover, increased mechanical strength decreases the plugging height on the ILRS targets. Based on the projectile residual velocities, the equivalent target strength parameter R were calculated and fitted to a functional relationship with the uniaxial compressive strength. RHT model parameters were calibrated using the test results of the dynamic and static mechanical properties of the simulants. Numerical simulation of projectile penetration into semi-infinite and thick targets were conducted using the calibrated model. The simulation results demonstrate high consistency with the experimental and theoretical calculations, indicating the effectiveness of the constitutive model in describing the mechanical response of the ILRS under projectile penetration.

Ever since the Lunar Crater Observation and Sensing Satellite (LCROSS) data helped confirm the presence of water in the permanently shadowed regions (PSRs) of the lunar polar area, interest in developing systems for the production of water on the Moon has peaked. Considering the extremely cold environment on the lunar surface, geotechnical properties of icy lunar regolith could have notable variance depending on water content and cryogenic environment. It is essential to have an in-depth understanding of the geotechnical properties of icy lunar regolith under varying conditions such as different water contents and cryogenic temperatures. Previous studies have shown that icy regolith behaves similarly to rock, depending on the water content and degree of compaction. Characterizing icy regolith is critical for any drilling and excavation operations for the development of the bases or for mining activities. This study estimated geotechnical behaviors of icy lunar regolith in cryogenic environments. Geotechnical tests such as unconfined compressive strength (UCS), Brazilian tensile strength (BTS), and punch penetration tests were conducted in simulated lunar cryogenic environments on samples of basaltic lunar simulant with changing water content. The results indicate that geotechnical properties of icy lunar regolith vary substantially in simulated moon environments. Icy lunar regolith tends to behave like rock with soft to medium strengths but has nonbrittle (or ductile) properties. Correlations between strength properties and water content as well as between strength properties and cryogenic temperature are offered. The results of this paper could provide valuable suggestions for future mining and civil activities and other exploration purposes on the moon. The results of mechanical characterization of icy regolith provided in this paper, such as UCS, BTS, and punch penetration tests to determine ductility and brittleness, are among the novel aspect of the study to offer better understanding of the behavior of such materials in future mining and construction activities on the moon.

The extraction and utilization of water ice resources in the lunar polar region is one of the important supporting technologies for the construction and sustainable operation of lunar bases. The development and utilization plan, implementation plan and development trend of water ice resources in the lunar polar region at home and abroad were investigated. Based on the selection of the work site in the permanently shaded regions of the lunar south pole, a system of sustainable lunar water resources extraction and utilization was proposed. The system is composed of three parts:mobile base vehicle, mobile in-situ drilling vehicle and mobile mirror set. It has the ability of flexible arrangement to continuously extract water ice resources in the shadow craters. The material flow and energy flow of the designed scheme were calculated and modeled, and the program analysis was carried out. The calculation results show that improving the solar energy transfer efficiency, photoelectric conversion efficiency, heating efficiency, and electrolysis efficiency, as well as improving the initial water ice content when it is lower than 5.0%, can significantly reduce the total energy consumption of the system task. Reducing the initial temperature of the icy lunar soil and the improvement of water purification efficiency have a negligible increase in the total energy consumption of the mission. The system design and analysis results can provide a reference for China's lunar base mission.

The icy lunar regolith (ILR) in the permanently shadowed regions (PSRs) of the lunar poles is an important lunar water resource for humans, which can be efficiently explored in situ by using a high-speed kinetic penetrator. The dynamic mechanical properties of ILR need priority research since they are related to the ballistics and overload of the penetrator. Based on ILR occurrence form and microscopic composition analyses, four types of ILR simulant (ILRS) specimens with typical water contents are prepared in the present study according to the principle of similar mineral composition and physical state. The dynamic mechanical properties of the ILRS specimens are investigated by combining the results of split Hopkinson pressure bar (SHPB), quasi-static unconfined compression, and variable angle shear (VAS) tests. The results show that the loading strain rates alter the microcrack number and expansion rate of the specimens, which in turn significantly affects their damage mode, dynamic uniaxial compressive strength (DUCS) and toughness ratio. Finally, based on the relationship between stress and strain in the SHPB tests, the damage properties of the ILRS under dynamic loading are analyzed, and a segmental constitutive model is provided by combining it with the Drucker-Prager strength theory. The research results could form the basis for subsequent penetrator structure design and ballistic prediction.

Water ice exists in the permanently shadowed region (PSR) of the moon. It can become a vital survival material for the lunar base and provide fuel for the moon to make the moon a relay station for deep space exploration. For in-situ sampling and detection of lunar water ice, the design of sampling equipment has to consider the mechanical properties of the icy lunar regolith (ILR) to be broken during the drilling process. According to the mineral and chemical composition of the soil in the PSR, basalt rocks and anorthosite rocks are selected as two basic raw materials to simulate lunar soil. Multiple sets of ILR simulated samples are prepared with different raw material ratios (five kinds), water content (5-25 wt%), dry density (bulk density, excluding water, 1.45-1.97 g/cm(3)), and temperature (-240 to-10 degrees C). Uniaxial compressive strength (UCS) tests are carried out on these samples. A comprehensive mapping model between the UCS and the above four factors is constructed using multiple nonlinear regression methods. Based on the existing remote sensing data, the relationships or hypotheses of the subsurface dry density, temperature, and water content with depth are given. Furthermore, the UCS and drillability grade of ILR are predicted to change with depth. The results show that the ratio of raw materials has far less influence on the UCS than the other three factors. When the sample temperature is lower than-180 degrees C, the degree of influence of temperature changes on the UCS is significantly reduced. The UCS of the sample increases nonlinearly with the increase of dry density. The samples have an extreme strength value in the saturated water content state. This study provides a standard for the design of the equipment for drilling detection of water ice and lays a foundation for presetting operating procedures of the drilling tool. (C) 2022 COSPAR. Published by Elsevier B.V. All rights reserved.