Understanding the mechanical behaviour of water ice-bearing lunar soil is essential for future lunar exploration and construction. This study employs discrete element method (DEM) simulations, incorporating realistic particle shapes and a flexible membrane, to investigate the effects of ice content, initial packing density, and gravitational conditions on lunar soil behaviour. Initially, we calibrated DEM model parameters by comparing triaxial tests on lunar soil without ice to physical experiments and the angle of repose simulations, validating the accuracy of our approach. Building on this, we conducted simulations on water ice-bearing lunar soil, examining stress-strain responses, shear strain, bond breakage, deviatoric fabric, and N-ring structures. DEM simulations demonstrate that increasing ice content from 0 % to 10 % elevates peak strength from 85 kPa to 240 kPa in loose samples and from 0.2 MPa to 1.62 MPa in dense samples. This strengthening aligns with microstructural stabilization evidenced by 5-ring configurations and narrowed branch vector distributions. Strain field analysis reveals greater deformation magnitudes in icy regolith, suggesting a trade-off between enhanced load-bearing capacity and reduced ductility. These quantified mechanical responses, including strength gain, structural stabilization, and strain localization, reveal the dual engineering implications of water ice in lunar soil.

Investigating water ice content at different locations on the Moon is crucial for crewed space missions and serves as a foundation for establishing lunar bases, which necessitates lunar soil sampling to gather information. Aiming to minimize the water ice loss caused by heat generation during drilling, this paper proposes a water ice highconservation sampling system based on frozen CO2 spray cooling. The thermodynamic and hydrodynamic models of the frozen CO2 generation subsystem and heat exchange subsystem are established. The impact of design parameters, flow and thermal conditions, and operation modes on water content has been analyzed. The spray cooling method indirectly affects the lunar soil temperature by reducing the drill bit temperature to increase the water conservation ratio (WCR) during drilling. The method combines frozen CO2 sublimation heat flow and jet cooling flow. Jet cooling is closely associated with the temperature difference between the fluid and the drill bit, as well as the flow velocity. Meanwhile, sublimation heat flow depends on the temperature difference between the drill bit and the saturation temperature of frozen CO2, along with the content of frozen CO2. Jet cooling is predominant at lower mass flow rates, while sublimation cooling prevails at higher rates. In addition, the time the lunar soil is at low-sublimation temperature is an important factor in WCR. Thus, to increase WCR, one can enhance flow velocity by reducing the nozzle diameter, raise sublimation heat flow by increasing mass flow and lowering the initial temperature, and maintain lunar soil at low-sublimation temperatures by increasing cooling time, duty ratio and decreasing the cooling period. Among others, increasing the cooling time has the most significant effect. The increasing slopes of WCR with cooling durations are about 20 %/100 s (at 0.4 g/s, liquid CO2) and 10 %/100 s (at 0.1 g/s, liquid CO2). However, the cooling time should not exceed the drilling time. This study provides an effective water ice conservation system that is useful for other planetary sampling missions.

Previous studies have reported the existence of water ice in the lunar polar regions, but estimations of water ice using different methods vary in certainty, precision, location, and abundance. Spectral analysis is one of the major ways for estimating lunar water ice abundance. However, low spatial resolution and signal-to-noise ratio are the disadvantages of hyperspectral images. In this study, the images captured by the multi-band imager (MI), characterized by higher spatial resolution and signal-to-noise ratio than hyperspectral images, onboard the Japanese Moon orbiter Selenological and Engineering Explorer (SELENE), are used to retrieve water ice in lunar polar regions. We analyzed reflectance in near-infrared bands after topographic correction to reduce the misinterpretation of the properties of the lunar surface. Through qualitative spectral analysis and quantitative water ice retrieval, the water ice abundance of sunlit areas in Shackleton Crater, de Gerlache Rims 1 and 2, Connecting Ridge, Connecting Ridge extension, and Peak Near Shackleton are obtained. The sunlit inner wall of Shackleton Crater has the highest possibility to contain water ice among the four regions, the estimated abundance ranges from 2 to 3 wt.%, which is consistent with previous studies in terms of order of magnitude. Reproducibility test suggests that the parallax effect of MI is small to ensure robust conclusions. When artificial noise was introduced, water ice abundance variations were limited to 1 wt.% in only a few areas, revealing that the results exhibit robustness against noise interference.

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.

Distinguishing the origin of lunar water ice requires in situ isotopic measurements with high sensitivity and robustness under extreme lunar conditions; however, challenges such as uncertain water contents and isotopic fractionation induced by regolith particles restrict isotopic analysis. Herein, we present a miniaturized tunable diode laser absorption spectrometer (TDLAS) developed as the core prototype for the Chang'E-7 Lunar Soil Water Molecule Analyzer (LSWMA). The wavelength range of the instrument is 3659.5-3662.0 cm-1, and the system integrates a Herriott cell for stable multi-isotope (H2 16O, H2 18O, H2 17O, and HD16O) detection and employs regolith samples of known isotopic experiments to quantify adsorption-induced fractionation. Performance evaluations demonstrated a dynamic water detection range of 0.01-2 wt % and isotope precision up to 1.3 parts per thousand for delta D (30.5 s), 0.77 parts per thousand for delta 18O (36 s), and 0.75 parts per thousand for delta 17O (21.5 s) with extended averaging. Repeated injections of three types of standard water revealed a volume-dependent deviation (Delta delta D up to -59.5 parts per thousand) attributed to multilayer adsorption effects, while simulated lunar soil experiments identified additional isotopic fractionation (Delta delta D up to -12.8 parts per thousand) caused by particle binding. These results validate the ability of the spectrometer to resolve subtle isotopic shifts under lunar conditions, providing critical data for distinguishing water origins and advancing future resource utilization strategies.

An increasing amount of evidence indicates that lunar water ice exists in permanently shadowed regions at the poles and will soon become an important resource for lunar exploration. However, the water ice content and distribution are still uncertain. We report a new 70-cm-wavelength radar image of the lunar south pole obtained by an Earth-based bistatic radar system consisting of the Sanya incoherent scatter radar (SYISR) and the five-hundred-meter aperture spherical radio telescope (FAST). The upper limit of water ice content (0 wt.%-6 wt.%) and its potential distribution are determined from a radar circular polarization ratio (CPR) map by considering the coherent backscatter opposition effect (CBOE) of water ice and ignoring the contribution of roughness to the CPR. This result is advantageous for future lunar exploration missions. (c) 2025 The Authors. Published by Elsevier B.V. and Science China Press. This is an open access article under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/).

This paper presents an ultrasonic sampling penetrator with a staggered-impact mode, which has been developed for the extraction of lunar water ice. A comparison of this penetrator with existing drilling and sampling equipment reveals its effectiveness in minimizing disturbance to the in situ state of lunar water ice. This is due to the interleaved impact penetration sampling method, which preserves the original stratigraphic information of lunar water ice. The ultrasonic sampling penetrator utilizes a single piezoelectric stack to generate the staggered-impact motion required for the sampler. Finite element simulation methods are employed for the structural design, with modal analysis and modal degeneracy carried out. The combined utilization of harmonic response analysis and transient analysis is instrumental in attaining the staggered-impact motion. The design parameters were then used to fabricate a prototype and construct a test platform, and the design's correctness was verified by the experimental results. In future sampling of lunar water ice at the International Lunar Research Station, the utilization of the ultrasonic sampling penetrator is recommended.

The presence of water in lunar materials can significantly impact the evolution of lunar geology and environment, as well as provide necessary conditions for the utilization of lunar resources. However, due to the limitations of lunar remote sensing methods, it is challenging to obtain direct evidence of water or determine its form of occurrence. Laser Raman spectroscopy, on the other hand, can provide valuable information on the type, distribution, and content of water in lunar materials without the need for illumination, sample pretreatment, or destructive measures. In this study, we utilized Raman spectroscopy to detect and quantify the water-containing characteristics of typical lunar rocks and minerals, including adsorbed water, ice, crystalline water, and hydroxyl-structured water. First, we used a 532 nm laser micro-Raman spectroscopy to identify and analyze the water-containing signals of various forms of water in lunar soil simulants. We then examined and analyzed the detection limits of adsorbed water, crystalline water, and hydroxyl- structured water in these simulants, as well as the relationship between their content and signal intensity. Finally, we employed linear regression (LR), ridge regression (RR), and partial least squares regression (PLSR) to quantitatively analyze the contents of these three forms of water in the lunar soil simulants. Our results demonstrate that the characteristic spectral peaks of the four forms of water in the lunar soil simulants can be clearly identified, with peak distribution regions located at 100-1 700 cm(-1) and 2 600-3 900 cm(-1) for the lunar soil components and water bodies, respectively. The spectral peaks of water are a combination of broad envelope peaks of hydrogen-bonded OH and sharp peaks of non- hydrogen-bonded OH stretching vibrations in varying proportions. The detection limits for adsorbed water, crystalline water (MgSO47H(2)O), and hydroxyl water (Al2Si2O5(OH)(4)) in the lunar soil simulants are 1.3 wt%, 0. 8 wt%, and 0. 3 wt%, respectively. There is a linear relationship between the intensity of water-containing peaks and the water content in the lunar soil simulants, with root mean square errors of 1. 75 wt%, 1. 16 wt%, and 1. 19 wt% obtained through LR, RR, and PLSR.

This study investigates the detectability of a putative layer of regolith containing water ice in the lunar polar regions using ground penetrating radar (GPR). Numerical simulations include realistic variations in the relative permittivity of the lunar regolith, considering both density and, for the first time, the effects of temperature on permittivity profiles. We follow the case of previous theoretical studies of water migration, which suggest that water ice accumulates at depths ranging from a few centimeters to tens of centimeters, appropriate depths to explore using GPR. In particular, frequency-modulated continuous wave (FMCW) radar is well-suited for this purpose due to its high range resolution and robust signal-to-noise ratio. This study evaluates two scenarios for the presence of lunar water ice: (1) a layer of regolith containing water ice at a depth of 5 cm, with a thickness of 5 cm, and (2) a layer of regolith containing water ice at a depth of 20 cm, with a thickness of 10 cm. Our computational results show that FMCW GPR, equipped with a dynamic range of 90 dB, is capable of detecting reflections from the interfaces of these layers, even under conditions of low water ice content and using antennas with low directivity. In addition, optimized antenna offsets improve the resolution of the upper and lower interfaces, particularly when applied to the surface of ancient crater ejecta. This study highlights the critical importance of understanding subsurface density and temperature structures for the accurate detection of water-ice-bearing regolith layers.

Permanently shadowed regions (PSRs) on the Moon are potential reservoirs for water ice, making them hot spots for future lunar exploration. The water ice in PSRs would cause distinctive changes in space weathering there, in particular reduction-oxidation processes that differ from those in illuminated regions. To determine the characteristics of products formed during space weathering in PSRs, the lunar meteorite NWA 10203 with artificially added water was irradiated with a nanosecond laser to simulate a micrometeorite bombardment of lunar soil containing water ice. The TEM results of the water-incorporated sample showed distinct amorphous rims that exhibited irregular thickness, poor stratification, the appearance of bubbles, and a reduced number of npFe0. Additionally, EELS analysis showed the presence of ferric iron at the rim of the nanophase metallic iron particles (npFe0) in the amorphous rim with the involvement of water. The results suggest that water ice is another possible factor contributing to oxidation during micrometeorite bombardment on the lunar surface. In addition, it offers a reference for a new space weathering model that incorporates water in PSRs, which could be widespread on asteroids with volatiles.