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.

As a crucial component of transportation networks, major railroad projects inevitably lead to ecological damage during the construction phase. Therefore, early warning systems for ecological health are essential for promoting effective ecological governance. This study proposes an ecological health evaluation index based on the PSR (Pressure-State-Response) model. Furthermore, the study establishes a status warning model for projects using system dynamics theory with a focus on ecology, environment, and resources; and conducts simulation modeling to assess ecological health along the railway lines. The study identified that the water supply increased from 0 to 269.376 million cubic meters, and new soil and water runoff increased from 0 to 992.912 tons from 2015 to 2018. In contrast, construction wastewater and domestic wastewater remained stable at 0.63 tons and 0.32 tons, respectively, throughout the construction period. Ecological restoration improved accordingly and gradually stabilized in the following years. The empirical findings from the railway project indicate that: (1) Expansion of construction land imposes a burden on the region's natural ecology and with the implementation of ecological protection helping to reduce the extent of ecological damage; (2) Major railroad projects have led to pollution of the regional water environment, necessitating alignment with local policies for comprehensive environmental management throughout the construction process; (3) Economic development drives increased energy consumption and water resource pressures in the construction region, highlighting the importance of resource efficiency for sustainable development. The early warning evaluation model proposed in this study enhances prediction and evaluation tools for the ecological governance of major railways, thereby offering specific preventive and governance measures for ecological and sustainable construction of major transportation projects.

Studies of the lunar surface from Synthetic Aperture Radar (SAR) data have played a prominent role in the exploration of the lunar surface in recent times. This study uses data from SAR sensors from three Moon missions: Chandrayaan-1 Mini-SAR, Lunar Recon-naissance Orbiter (LRO) Mini-RF and Chandrayaan-2 Dual Frequency Synthetic Aperture Radar (DFSAR). DFSAR sensor is the first of its kind to operate at L-band and S-band in fully and hybrid polarimetric modes. Due to the availability of only L-band data out of the two bands (L-and S-band) for the study site, this study only used DFSAR's L-band data. The dielectric characterization and polarimetric analysis of the lunar north polar crater Hermite-A was performed in this study using Chandrayaan-1 Mini-SAR, LRO Mini-RF and Chandrayaan-2 DFSAR data. Hermite-A lies in the Permanently Shadowed Region (PSR) of the lunar north pole and whose PSR ID is NP_879520_3076780. Because of its location within the PSR of the lunar north pole, the Hermite-A makes an ideal candidate for a probable location of water-ice deposits. This work utilizes S-band hybrid polarimetric data of Mini-SAR and Mini-RF and L -band fully polarimetric data of DFSAR for the lunar north polar crater Hermite-A. This study characterizes the scattering mechanisms from three decomposition techniques of Hybrid Polarimetry namely m-delta, m-chi, and m-alpha decompositions, and for fully polari-metric data Barnes decomposition technique was applied which is based on wave dichotomy. Eigenvector and Eigenvalue-based decom-position model (H-A-Alpha decomposition) was also applied to characterize the scattering behavior of the crater. This study utilizes the hybrid-pol and fully polarimetric data-based Integral Equation Model (IEM) to retrieve the values of dielectric constant for Hermite-A crater. The dielectric constant values for the Hermite-A crater from Chandrayaan-1 Mini-SAR and LRO Mini-RF are similar, which goes further in establishing the presence of water-ice in the region. The values of the dielectric constant for Chandrayaan-2 in some regions of the crater especially on the left side of the crater is also around 3 but overall the range is relatively higher than the com-pact/hybrid polarimetric data. The dielectric characterization and polarimetric analysis of the Hermite-A indicatively illustrate that the crater may have surface ice clusters in its walls and on some areas of the crater floor, which can be explored in the future from the synergistic use of remote sensing data and in-situ experiments to confirm the presence of the surface ice clusters.(c) 2022 COSPAR. Published by Elsevier B.V. All rights reserved.

The lunar polar regions offer permanently shadowed regions (PSRs) representing the only regions which are cold enough for water ice to accumulate on the surface. The Lunar Exploration Neutron Detector (LEND) aboard the Lunar Reconnaissance Orbiter (LRO) has mapped the polar regions for their hydrogen abundance which possibly resides there in the form of water ice. Neutron suppression regions (NSRs) are regions of excessive hydrogen concentrations and were previously identified using LEND data. At each pole, we applied thermal modeling to three NSRs and one unclassified region to evaluate the correlation between hydrogen concentrations and temperatures. Our thermal model delivers temperature estimates for the surface and for 29 layers in the sub-surface down to 2 m depth. We compared our temperature maps at each layer to LEND neutron suppression maps to reveal the range of depths at which both maps correlate best. As anticipated, we find the three south polar NSRs which are coincident with PSRs in agreement with respective (near)-surface temperatures that support the accumulation of water ice. Water ice is suspected to be present in the upper approximate to 19 cm layer of regolith. The three north polar NSRs however lie in non-PSR areas and are counter-intuitive as such that most surfaces reach temperatures that are too high for water ice to exist. However, we find that temperatures are cold enough in the shallow sub-surface and suggest water ice to be present at depths down to approximate to 35-65 cm. Additionally we find ideal conditions for ice pumping into the sub-surface at the north polar NSRs. The reported depths are observable by LEND and can, at least in part, explain the existence and shape of the observed hydrogen signal. Although we can substantiate the anticipated correlation between hydrogen abundance and temperature the converse argument cannot be made.

Knowledge of the amount of water ice on the lunar surface will play a crucial role in future lunar missions. The discovery of large quantities of water ice on the Moon will have very significant implications for human space exploration. In this letter, the methodology for quantification of water ice is developed. Quantification of water ice present in the permanently shadowed region (PSR) of Hermite-A Crater is done by comparing simulated dielectric constant values obtained using the Campbell model and laboratory-measured dielectric constant values of terrestrial analogue of lunar soil for various percentages of water ice content. From this analysis, it is observed that about 66.32% of the total PSR of Hermite-A Crater is covered with different percentages of water ice. In this letter, all the pixels of the PSR of Hermite-A Crater, with a spatial resolution of 7.4 m/pixel, have been mapped with their corresponding water ice content ranging from 0% to 9%.

The primary objective of the Lunar Crater Observation and Sensing Satellite (LCROSS) was to confirm the presence or absence of water ice in a permanently shadowed region (PSR) at a lunar pole. LCROSS was classified as a NASA Class D mission. Its payload, the subject of this article, was designed, built, tested and operated to support a condensed schedule, risk tolerant mission approach, a new paradigm for NASA science missions. All nine science instruments, most of them ruggedized commercial-off-the-shelf (COTS), successfully collected data during all in-flight calibration campaigns, and most importantly, during the final descent to the lunar surface on October 9, 2009, after 112 days in space. LCROSS demonstrated that COTS instruments and designs with simple interfaces, can provide high-quality science at low-cost and in short development time frames. Building upfront into the payload design, flexibility, redundancy where possible even with the science measurement approach, and large margins, played important roles for this new type of payload. The environmental and calibration approach adopted by the LCROSS team, compared to existing standard programs, is discussed. The description, capabilities, calibration and in-flight performance of each instrument are summarized. Finally, this paper goes into depth about specific areas where the instruments worked differently than expected and how the flexibility of the payload team, the knowledge of instrument priority and science trades, and proactive margin maintenance, led to a successful science measurement by the LCROSS payload's instrument complement.

One of the most exciting recent developments in the field of lunar science has been the unambiguous detection of water (either as OH or H(2)O) or water ice on the Moon through instruments flown on a number of orbiting spacecraft missions. At the same time, continued laboratory-based investigations of returned lunar samples by Apollo missions using high-precision, low-detection, analytical instruments have for the first time, provided the absolute abundance of water (present mostly as structurally bound OH(-) in mineral phases) in lunar samples. These new results suggest that the Moon is not an anhydrous body, questioning conventional wisdom, and indicating the possibility of a wet lunar interior and the presence of distinct reservoirs of water on the lunar surface. However, not all recent results point to a wet Moon and it appears that the distribution of water on the Moon may be highly heterogeneous. Additionally, a number of sources are likely to have contributed to the water inventory of the Moon ranging from primordial water to meteorite-derived water ice through to the water formed during the reaction of solar-wind hydrogen with the lunar soil. Water on the Moon has implications for future astrobiological investigations as well as for generating resources in situ during future exploration of the Moon and other airless bodies in the Solar System.

The Lyman Alpha Mapping Project (LAMP) is a far-ultraviolet (FUV) imaging spectrograph on NASA's Lunar Reconnaissance Orbiter (LRO) mission. Its main objectives are to (i) identify and localize exposed water frost in permanently shadowed regions (PSRs), (ii) characterize landforms and albedos in PSRs, (iii) demonstrate the feasibility of using natural starlight and sky-glow illumination for future lunar surface mission applications, and (iv) characterize the lunar atmosphere and its variability. As a byproduct, LAMP will map a large fraction of the Moon at FUV wavelengths, allowing new studies of the microphysical and reflectance properties of the regolith. The LAMP FUV spectrograph will accomplish these objectives by measuring the signal reflected from the night-side lunar surface and in PSRs using both the interplanetary HI Lyman-alpha sky-glow and FUV starlight as light sources. Both these light sources provide fairly uniform, but faint, illumination. With the expected LAMP sensitivity, by the end of the primary 1-year LRO mission, the SNR for a Lyman-alpha albedo map should be > 100 in polar regions > 1 km(2), providing useful FUV constraints to help characterize subtle compositional and structural features. The LAMP instrument is based on the flight-proven Alice series of spectrographs flying on the Rosetta comet mission and the New Horizons Pluto mission. A general description of the LAMP instrument and its initial ground calibration results are presented here.

The Diviner Lunar Radiometer Experiment on NASA's Lunar Reconnaissance Orbiter will be the first instrument to systematically map the global thermal state of the Moon and its diurnal and seasonal variability. Diviner will measure reflected solar and emitted infrared radiation in nine spectral channels with wavelengths ranging from 0.3 to 400 microns. The resulting measurements will enable characterization of the lunar thermal environment, mapping surface properties such as thermal inertia, rock abundance and silicate mineralogy, and determination of the locations and temperatures of volatile cold traps in the lunar polar regions.