The recent combination of significantly reduced launch costs and the confirmed presence of water ice on the Moon presents new opportunities for lunar construction beyond the constraints of traditional In-Situ Resource Utilization (ISRU). This study investigates an alternative approach that incorporates Earth-supplied cement with lunar-derived resources to manufacture concrete directly on the lunar surface. In this concept, cement is transported from Earth, while lunar rocks are processed into aggregate and water ice is electrolyzed to provide the water and atmosphere necessary for concrete mixing. The resulting precast blocks are assembled into modular arch structures and covered with regolith for thermal and radiation protection. A comparative cost analysis shows that if launch costs fall from current levels (approximately US $1,410/kg) to projected levels under systems like Starship (US $10/kg), transportation costs for materials and equipment to build a habitat for two could drop from around US $138.6 million to just US $0.98 million. This roughly 99% reduction implies that conventional concrete-based construction may become economically viable for early lunar infrastructure. However, further research is needed in key areas such as performance of concrete structure under vacuum condition, in-situ water extraction efficiency, and optimization of regolith covering design.

Seepage problems in half-space domains are crucial in hydrology, environmental, and civil engineering, involving groundwater flow, pollutant transport, and structural stability. Typical examples include seepage through dam foundations, coastal aquifers, and levees under seepage forces, requiring accurate numerical modeling. However, existing methods face challenges in handling complex geometries, heterogeneous media, and anisotropic properties, particularly in multi-domain half-spaces. This study addresses these challenges by extending the modified scaled boundary finite element method (SBFEM) and using this method to explore steady seepage problems in complex half-space domain. In the modified SBFEM framework, segmented straight lines or curves, parallel to the far-field infinite boundary, are introduced as scaling lines, with a one-dimensional discretization applied to them, thereby reducing computational costs.Then the weighted residual method is applied to obtain the modified SBFEM governing equations and boundary conditions of steady-state seepage problem according to the Laplace diffusion equation and Darcy's law. Furthermore, the steady seepage matrix at infinity is obtained by solving the eigenvalue problem of Schur decomposition and then the 4th-order Runge-Kutta algorithm is used to iteratively solve until the seepage matrix at the boundary lines is reached. Comparisons between the present numerical results and solutions available in the published work have been conducted to demonstrate the efficiency and accuracy of this method. At the same time, the influences of the geometric parameters and complex half-space domain on the seepage flow characteristics in complex half-space domain are investigated in detail.

Space weathering has long been known to alter the chemical and physical properties of the surfaces of airless bodies such as the Moon. The isotopic compositions of moderately volatile elements in lunar regolith samples could serve as sensitive tracers for assessing the intensity and duration of space weathering. In this study, we develop a new quantitative tool to study space weathering and constrain surface exposure ages based on potassium isotopic compositions of lunar soils. We first report the K isotopic compositions of 13 bulk lunar soils and 20 interval soil samples from the Apollo 15 deep drill core (15004-15006). We observe significant K isotope fractionation in these lunar soil samples, ranging from 0.00 %o to + 11.77 %o, compared to the bulk silicate Moon (-0.07 +/- 0.09 %o). Additionally, a strong correlation between soil maturity (Is/FeO) and K isotope fractionation is identified for the first time, consistent with other isotope systems of moderately volatile elements such as S, Cu, Zn, Se, Rb, and Cd. Subsequently, we conduct numerical modeling to better constrain the processes of volatile element depletion and isotope fractionation on the Moon and calculate a new K Isotope Model Exposure Age (KIMEA) through this model. We demonstrate that this KIMEA is most sensitive to samples with an exposure age lower than 1,000 Ma and becomes less effective for older samples. This novel K isotope tool can be utilized to evaluate the surface exposure ages of regolith samples on the Moon and potentially on other airless bodies if calibrated using other methods (e.g., cosmogenic noble gases) or experimental data.

The long-term disposal of high-level radioactive waste (HLW) in deep geological repositories requires the reliable performance of engineered barrier systems (EBS). Compacted bentonite, widely used for its high swelling capacity, low permeability, and self-sealing properties, plays a critical role in these barriers. However, understanding the complex coupled thermo-hydro-mechanical (THM) behavior governing water infiltration dynamics remains a significant challenge, especially when gap spaces (or technological voids) are present. This study investigates water infiltration dynamics in bentonite-based EBS using a novel laboratory-scale experimental setup. Time-lapse photography was employed to monitor the evolution of hydration and swelling under thermal gradients and varying gap sizes, simulating repository conditions. The experimental program was designed to compare the effects of two gap sizes on infiltration rates, swelling behavior, and desiccation cracking. Results demonstrated that larger void spaces accommodated greater swelling, leading to lower dry density and higher permeability, while smaller gaps restricted desiccation cracking due to mechanical constraints. The correlation between pixel intensity and water content allowed the derivation of a linear calibration model, enabling real-time, non-destructive estimation of moisture distribution in bentonite. Findings in this study highlight the interplay between gap size, water infiltration, and thermal effects, emphasizing the need for optimized EBS designs to balance mechanical integrity and hydraulic performance. It is anticipated that the insights provided by this study contribute to the refinement of predictive models and advancing the safe and effective containment of HLW over geological timescales.

Space weathering alters the surface materials of airless planetary bodies; however, the effects on moderately volatile elements in the lunar regolith are not well constrained. For the first time, we provide depth profiles for stable K and Fe isotopes in a continuous lunar regolith core, Apollo 17 double drive tube 73001/2. The top of the core is enriched in heavy K isotopes (delta 41K = 3.48 +/- 0.05 parts per thousand) with a significant trend toward lighter K isotopes to a depth of 7 cm; while the lower 44 cm has only slight variation with an average delta 41K value of 0.15 +/- 0.05 parts per thousand. Iron, which is more refractory, shows only minor variation; the delta 56Fe value at the top of the core is 0.16 +/- 0.02 parts per thousand while the average bottom 44 cm is 0.11 +/- 0.03 parts per thousand. The isotopic fractionation in the top 7 cm of the core, especially the K isotopes, correlates with soil maturity as measured by ferromagnetic resonance. Kinetic fractionation from volatilization by micrometeoroid impacts is modeled in the double drive tube 73001/2 using Rayleigh fractionation and can explain the observed K and Fe isotopic fractionation. Effects from cosmogenic 41K (from decay of 41Ca) were calculated and found to be negligible in 73001/2. In future sample return missions, researchers can use heavy K isotope signatures as tracers of space weathering effects.

To the aim of this paper is to study the structural and environmental deformation characteristics caused by the excavation of a very large deep foundation pit in the sandy soil area of Beijing. This paper is based on numerical simulation and field monitoring results and these results are compared with the deformation data of a soft soil foundation pit in the Shanghai area. The results show that the influence of the environment surrounding the super-large deep foundation pit project studied in this paper is obviously too great. With the progress of construction, the deformation rate and deformation amount of the column at the side of the foundation pit are obviously higher than that of the column in the middle area. Due to the hysteresis of stress transfer in the sand, the settlement of the roof of the north wall is delayed and the deformation range is smaller than that of the south wall. Compared with the conventional foundation pit, the influence area of the surrounding surface is larger, reaching 4 He (He is the depth of the foundation pit). Delta vmax (the maximum surface settlement) is between 0.2 similar to 2.3% He, and the relationship between delta vmax = 1.43% Vwm. Through orthogonal experiments and numerical simulation, it is concluded that the deformation of foundation pit structure and its surrounding environment is more sensitive to excavation unloading, precipitation amplitude, and column spacing. It is also concluded that the strong, medium, and weak influence areas of the bottom uplift after foundation pit construction are (0 similar to 0.07) x L, (0.07 similar to 0.14) x L, and (0.14 similar to 0.5) x L, respectively (L is the width of foundation pit). When the embedment ratio is between 1.8 similar to 2.4, the displacement mode of the parapet structure is T mode; when the embedment ratio is between 2.4 similar to 3.4, the displacement mode of the parapet structure is RB mode.

This paper reviews electrodynamic dust shield (EDS) systems used to mitigate dust adhesion and accumulation on optical elements, such as photovoltaic (PV) panels. The EDS system uses an electrodynamic standing wave or travelling wave, generated by applying a two-phase or multi-phase high voltage to parallel line electrodes, to transport charged particles. After presenting a brief history of the research and development of EDS systems, theoretical and numerical investigations are introduced. They elucidate the mechanism of particle dynamics in the electrodynamic field and predict cleaning performance in low-gravity and low-pressure environments on the Moon and Mars. Subsequently, the paper presents the system configuration, including a cleaner plate and power supply, and fundamental characteristics, including the effects of electrode configuration, applied voltage and frequency, and environmental conditions. It also describes the current status of two primary applications of EDS systems: the cleaning of dust deposited on large-scale PV panels used in solar power generation plants and the cleaning of optical elements, such as PV panels, thermal radiators, lenses, and mirrors mounted on rovers for lunar and Martian exploration. In addition, future challenges are discussed, and other space applications are introduced, such as cleaning of spacesuits, transport and particle-size classification of lunar regolith for the insitu resource utilization, and sampling of regolith and water ice particles on the Moon and asteroids.

Observations of widespread hydration across the lunar surface could be attributed to water formed via the implantation of solar wind hydrogen ions into minerals at the surface. Solar wind irradiation produces a defectrich outer rim in lunar regolith grains which can trap implanted hydrogen to form and store water. However, the ability of hydrogen and water to be retained in space weathered regolith at the lunar surface is not wellunderstood. Here, we present results of novel and coordinated high-resolution analyses using transmission electron microscopy and atom probe tomography to measure hydrogen and water within space weathered lunar grains. We find that hydrogen and water are present in the solar wind-damaged rims of lunar grains and that these species are stored in higher concentrations in the vesicles that are formed by solar wind irradiation. These vesicles may serve as reservoirs that store water over diurnal and possibly geologic timescales. Solar windderived water trapped in space weathered rims is likely a major contributor to observations of the widespread presence, variability, and behavior of the water across the lunar surface.

This article investigates the use of a bespoke fund, the Space Resources Fund (SRF), to facilitate monetary benefit sharing from commercial space resource utilisation (SRU) and at the same time provide a source of funding for a developing space resource industry. The study investigates the possible objectives such a fund could have and compares these to range of terrestrial fund types that could have similar objectives. We find that there is no one fund type that could meet the possible objectives for a SRF, however, by combining several fund types, it is possible to construct a dedicated fund that meets the objectives initially developed. The study proposes a fund with the Double Bottom Line of both generating monetary benefits from commercial SRU and providing investment capital to an industry targeting SRU. The study also proposes a possible strategy, structure, funding mechanism and benefit distribution mechanism for the SRF and undertakes high level financial modelling to illustrate the wealth creation potential of such a fund. Further, we discuss the advantages and disadvantages of the approach proposed in this study compared to the use of a royalty mechanism for monetary benefit sharing, should monetary benefit sharing ultimately be proposed, by the UN Committee On the Peaceful Uses of Outer Space (COPUOS) for example. This work builds on previous work that reviews the ongoing debate concerning benefit sharing from commercial SRU and explores the use of royalties for such monetary benefit sharing in the context of commercial lunar ice mining. We conclude that a SRF as proposed here could help resolve the long standing dilemma of how to facilitate monetary benefit sharing from commercial SRU without impacting the development of such an industry.

The rich resources and unique environment of the Moon make it an ideal location for human expansion and the utilization of extraterrestrial resources. Oxygen, crucial for supporting human life on the Moon, can be extracted from lunar regolith, which is highly rich in oxygen and contains polymetallic oxides. This oxygen and metal extraction can be achieved using existing metallurgical techniques. Furthermore, the ample reserves of water ice on the Moon offer another means for oxygen production. This paper offers a detailed overview of the leading technologies for achieving oxygen production on the Moon, drawing from an analysis of lunar resources and environmental conditions. It delves into the principles, processes, advantages, and drawbacks of water-ice electrolysis, two-step oxygen production from lunar regolith, and one-step oxygen production from lunar regolith. The two-step methods involve hydrogen reduction, carbothermal reduction, and hydrometallurgy, while the one-step methods encompass fluorination/chlorination, high-temperature decomposition, molten salt electrolysis, and molten regolith electrolysis (MOE). Following a thorough comparison of raw materials, equipment, technology, and economic viability, MOE is identified as the most promising approach for future in-situ oxygen production on the Moon. Considering the corrosion characteristics of molten lunar regolith at high temperatures, along with the Moon's low-gravity environment, the development of inexpensive and stable inert anodes and electrolysis devices that can easily collect oxygen is critical for promoting MOE technology on the Moon. This review significantly contributes to our understanding of in-situ oxygen production technologies on the Moon and supports upcoming lunar exploration initiatives.