We present a high-resolution geologic map of the Rubin crater region, located on Mons Amundsen, which has been identified as a promising site for future lunar exploration (AOI E in Wueller et al., 2024). We developed a design reference mission (DRM) to highlight the region's potential for addressing key lunar science goals, particularly those related to the early lunar bombardment history, lunar crustal rocks, volatiles, impact processes at multiple scales, and regolith properties, as outlined by the National Research Council (2007). The Rubin crater, which formed about 1.58 billion years ago during the Eratosthenian period, excavated material from depths of up to 320 m, potentially reaching the underlying South Pole-Aitken (SPA) massif, Mons Amundsen. This makes the crater's ejecta material, along with the Amundsen ejecta covering the massif, prime targets for sampling SPA-derived materials that can expand our understanding of early Solar System dynamics and the lunar cratering chronology. Additionally, the region hosts several permanently shadowed regions (PSRs), ideal for studying potential lunar volatiles and the processes affecting their distribution. The DRM proposes nine traverse options for exploration via walking EVAs, the Lunar Roving Vehicle (LRV), and LRV-assisted EVAs, with traverse lengths ranging from 3.6 km to 18.2 km. Each traverse is designed to sample diverse geologic units and address multiple scientific objectives. Given its scientific potential and favorable exploration conditions, the Rubin crater region is an ideal location for testing south polar landing operations, potentially paving the way for more complex missions, such as a Shackleton crater landing. (c) 2025 The Author(s). Published by Elsevier B.V. on behalf of COSPAR. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).

From the scientific perspective, Artemis lunar missions focus on the south circumpolar region (SCR) mainly to investigate the existence and abundance of volatiles and to explore and sample ancient lunar deposits. The volatile distribution is primarily related to the cold traps in permanently shadowed regions, while the availability of ancient material is due to the proximity to the early lunar -2300 km diameter South Pole-Aitken (SPA) impact basin. One of the critical factors for future missions will be determining the geological structure and provenance (sources) of material at each candidate landing site, which can be predicted utilizing three-dimensional stratigraphic reconstructions of geological map units and crater ejecta deposits. This type of reconstruction permits a better understanding of candidate material that can be collected and analyzed at each site, and a ranking of landing sites can be formulated on this basis. Here, we present reconstructed geological cross-sections at Artemis landing sites using our recent SCR geological map and numerical modelling of crater ejecta thicknesses and their sequence.

The lunar south polar region is of specific interest with a much higher probability for finding water ice and volatile resources in the permanently shadowed regions (PSRs). Here, the uneven topography coupled with very low axial inclination of the Moon of similar to 1.5(o) helps in maintaining a perennial temperature below 110 K in relatively broad areas. Along with the possibility of finding water ice and other volatiles that can be used for future explorations, the south polar region is expected to be compositionally diverse being situated inside the South Pole Aitken Basin (SPA). Though several lunar polar missions were planned, none of them have yet experienced and explored the unique polar environment in-situ. Several sites have been identified majorly based on technical feasibility of landing. The polar sites are challenging to land due to the difficult terrain and limited information about its characteristics. In this study, we selected a ridge region connecting two PSRs: de-Gerlache and Shackleton, and evaluated four sites in that ridge and prioritized them based on the expected scientific outcomes and feasibility to access a PSR for volatile detection and quantification. Our detailed analysis of landing sites is based on terrain characteristics, which include slope, illumination, surface roughness, surface temperature, accessibility to nearby PSRs, compositional diversity, and trafficability. Moreover, multiple micro PSRs have been identified in close vicinity of four landing sites that can potentially trap water ice and other volatiles. We find that the site C1 (-136.2 degrees, - 89.406 degrees) situated on the ridge connecting de-Gerlache and Shackleton, and site D (-87.514 degrees, -89 degrees) situated on the rim of de-Gerlache are the most promising sites that can be considered for near future polar exploration missions. These sites provide opportunity of exploration utilizing solar power without compromising on scientific outcomes. Both the sites are found to be in close vicinity of PSR providing opportunities to sample volatiles. The sites C1 and D provide a good alternative to site S (-158.162 degrees, -89.769 degrees) located on Shackleton crater rim, which is considered to be scientifically enriched but technically challenging for landing.

In the future, lunar exploration will focus on long-term scientific exploration, identification and utilization of resources, and construction of lunar surface infrastructure, all within a framework of increasing international cooperation. Therefore, China has proposed to establish an international lunar research station (ILRS) in the lunar south polar region. The scientific and engineering suitability of the landing site is a critical element for scientific research station that will operate over years. Compared to previous landed missions, the detection and exploration of volatiles and their role in the history and evolution of the Moon and Solar System is a major new theme. Using multiple datasets, we (1) evaluate the breadth of scientific goals that can be achieved for two potential landing areas (Amundsen crater and Malapert crater) with accessible permanently shadowed regions (PSRs), and (2) examine exploration constraints posed by terrain, temperature, and illumination conditions. Based on this, we determined the landing sites and potential high value exploration areas for each landing area, as well as the science missions that could be performed. Our ILRS siting strategy, which focuses more on scientific constraints than engineering constraints, will provide guidance for possible future ILRS siting areas.

The last decades have been marked by increasing evidence for the presence of near-surface volatiles at the lunar poles. Enhancement in hydrogen near both poles, UV and VNIR albedo anomalies, high CPR in remotely sensed radar data have all been tentatively interpreted as evidence for surface and/or subsurface water ice. Lunar water ice and other potential cold-trapped volatiles are targets of interest both as scientific repositories for understanding the evolution of the Solar System and for exploration purposes. Determining the exact nature, extent and origin of the volatile species at or near the surface in the lunar polar regions however requires in situ measurements via lander or rover missions. A number of upcoming missions will address these issues by obtaining in situ data or by returning samples from the lunar surface or shallow subsurface. These all rely on the selection of optimal landing sites. The present paper discusses potential regions of interest (ROI) for combined volatile and geologic investigations in the vicinity of the lunar South Pole. We identified eleven regions of interest (including a broad area of interest (>200 km x 200 km) at the South Pole, together with smaller regions located near Cabeus, Amundsen, Ibn Bajja, Wiechert J and Idel' son craters), with enhanced near-surface hydrogen concentration (H > 100 ppm by weight) and where water ice is expected to be stable at the surface, considering the present-day surface thermal regime. Identifying more specific landing sites for individual missions is critically dependent on the mission's goals and capabilities. We present detailed case studies of landing site analyses based on the mission scenario and requirements of the upcoming Luna-25 and Luna-27 landers and Lunar Prospecting Rover case study. Suitable sites with promising science outcomes were found for both lander and rover scenarios. However, the rough topography and limited illumination conditions near the South Pole reduce the number of possible landing sites, especially for solar-powered missions. It is therefore expected that limited Sun and Earth visibility at latitudes >80 degrees will impose very stringent constraints on the design and duration of future polar missions.

Our understanding of the Moon has advanced greatly over the last several decades thanks to analyses of Apollo samples and lunar meteorites, and recent lunar orbital missions. Notably, it is now thought that the lunar poles may be much more enriched in H2O and other volatile chemical species than the equatorial regions sampled during the Apollo missions. The equatorial regions sampled, themselves, contain more H2O than previously thought. A new lunar mission to a polar region is therefore of great interest; it could provide a measure of the sources and processes that deliver volatiles while also evaluating the potential in situ resource utilization value they may have for human exploration. In this study, we determine the optimal sites for studying lunar volatiles by conducting a quantitative GIS-based spatial analysis of multiple relevant datasets. The datasets include the locations of permanently shadowed regions, thermal analyses of the lunar surface, and hydrogen abundances. We provide maps of the lunar surface showing areas of high scientific interest, including five regions near the lunar north pole and seven regions near the lunar south pole that have the highest scientific potential according to rational search criteria. At two of these sites a region we call the Intercrater Polar Highlands (IPH) near the north pole, and Amundsen crater near the south pole we provide a more detailed assessment of landing sites, sample locations, and exploration strategies best suited for future human or robotic exploration missions. (C) 2014 Elsevier Ltd. All rights reserved.

[1] Initial studies of neutron spectrometer data returned by Lunar Prospector concentrated on the discovery of enhanced hydrogen abundances near both lunar poles. However, the nonpolar data exhibit intriguing patterns that appear spatially correlated with surface features such as young impact craters (e. g., Tycho). Such immature crater materials may have low hydrogen contents because of their relative lack of exposure to solar wind-implanted volatiles. We tested this hypothesis by comparing epithermal* neutron counts (i.e., epithermal -0.057 x thermal neutrons) for Copernican-age craters classified as relatively young, intermediate, and old (as determined by previous studies of Clementine optical maturity variations). The epithermal* counts of the crater and continuous ejecta regions suggest that the youngest impact materials are relatively devoid of hydrogen in the upper 1 m of regolith. We also show that the mean hydrogen contents measured in Apollo and Luna landing site samples are only moderately well correlated to the epithermal* neutron counts at the landing sites, likely owing to the effects of rare earth elements. These results suggest that further work is required to define better how hydrogen distribution can be revealed by epithermal neutrons in order to understand more fully the nature and sources (e. g., solar wind, meteorite impacts) of volatiles in the lunar regolith.