The precise detection of water-ice distributions within the permanently shadowed regions (PSRs) of the lunar south polar region is of paramount importance. We applied a polarimetric method for water-ice detection (PM4W) that utilizes Mini-RF data. The PM4W method incorporates several key radar scattering properties with topographical and environmental characteristics to detect water-ice within the lunar south polar region of 87 degrees S-90 degrees S. The method successfully identified 1578 water-ice containing pixels (each representing a 30 m x 30 m area) in the lunar shallow subsurface (1-3 m) at the south polar region, of which 1445 (similar to 91%) are spatially clustered in 29 PSRs. When comparing Mini-RF with M3 (each point representing a 280 m x 280 m area) using a buffer-based fuzzy assessment method, we found a pixel consistency of 60% and area consistency of 11%, which can be attributed to the differences in spatial resolution, positioning accuracy, and depth sensitivity. Moreover, over 90% of the water-ice pixels detected by Mini-RF are located within PSRs, accounting for 0.025% of their total area. In contrast, only 68% of the pixels detected by M3 are within PSRs, covering 0.760% of the PSRs area, which is approximately 30 times greater than the Mini-RF detections. The finer spatial resolution of the Mini-RF enables it to reveal previously undetectable features that align with the environmental mechanisms of water-ice storage. Our work contributes to assessing the potential presence of water-ice in vital exploration areas, providing pertinent indications for future lunar probes to identify water-ice on the Moon directly.

An increase in the temperature of permafrost that is caused by global warming can lead to a significant decrease in shear strength. Seasonal freeze-thaw (F-T) cycles can also adversely affect the shear strength of soils. This can result in damages to infrastructure, negative impacts on the economy, and a decline in the quality of life. Thus, it is crucial to understand the shear strength of permafrost and seasonally frozen-thawed soils. Several studies have utilized various instruments to observe the behavior of soils under such conditions, including a temperature-controlled triaxial system to apply F-T cycles or a traditional direct shear apparatus placed within a temperature-controlled room. Since most commercial geotechnical labs do not have a temperature-controlled room or a temperature-controlled triaxial system, this article presents the design of a new cost-effective direct shear box that was developed to allow temperature-controlled testing in a traditional direct shear device. The modifications to the direct shear box comply with ASTM D3080/3080M, Standard Test Method for Direct Shear Test of Soils under Consolidated Drained Conditions. Like the standard direct shear box, it consists of two halves and a direct shear cap, but each of these components is hollow to allow for the circulation of glycol. The chiller is capable of imposing temperatures within the range of -40 degrees C to +40 degrees C on the sample being tested. It is also possible to freeze and thaw specimens at a desired normal stress while monitoring the associated heave and compression. The freezing mechanism applied to the soil sample affects the distribution of ice within the pore spaces, necessitating that samples be frozen from all sides if a uniform distribution of ice is necessary. Shear strength parameters from the newly designed temperature-controlled direct shear box matched well with those from the traditional shear box. In addition, the feasibility of temperature-controlled direct shear testing was evaluated at different temperatures, strain rates, and normal stresses.