The subject of the work is the analysis of satellite data in the database LROC: QuickMap. The article focuses on water ice deposits which could be converted into hydrogen or oxygen, among other things, and later used as a rocket fuel. The distribution of water ice deposits on the Moon is presented and a micro-trap on the Moon's south pole is proposed, which in the future could be an object for the exploration of water ice. An exit and descent route to the crater floor for the rover was also proposed, considering the degree of insolation and the degree of slope of the crater walls.
Due to the smaller axial tilt of the Moon, interiors of some of the polar craters on the lunar surface never get sunlight and are considered to be permanently shadowed regions. Several of such regions are known to contain water-ice deposits. These regions are expected to show elevated values of circular polarization ratio (CPR). Hence, the interiors of craters containing water-ice deposits are characterized by elevated CPR values as observed by the S-band synthetic aperture radar (Mini-SAR) on-board Chandrayaan-1 mission of ISRO. However, elevated CPR values were also observed from the interiors of some non-polar craters and also from young, fresh polar craters. Thus, elevated CPR values are not a unique signature of water-ice deposits. Therefore, additional information related to geological setting and roughness patterns should also be considered while identifying the regions containing water-ice deposits. For identifying a unique signature of water-ice deposits, analysis of radar scattering mechanism in elevated CPR regions was carried out. Areas of elevated CPR due to double-bounce and surface scattering conditions were segmented and polarimetric, backscattering properties of diffuse scatterers were analysed. Based on the signatures of diffuse scatterers and radar backscattering coefficient, a scattering mechanism-based algorithm was developed, which has the advantage in classifying regions showing elevated CPR due to surface and double-bounce scattering effects. The algorithm was then tested using Mini-SAR data and it was also found to be useful in eliminating regions of elevated CPR in fresh craters observed due to the double-bounce effect.
In an attempt to reduce the ambiguity on radar detection of water ice at the permanently shadowed regions near the lunar poles, radar echo strength and circular polarization ratio (CPR) of impact craters are analyzed using the Miniature Radio Frequency (Mini-RF) radar data from the Lunar Reconnaissance Orbiter mission. Eight typical craters, among over 70 craters, are selected and classified into four categories based on their locations and CPR characteristics: polar anomalous, polar fresh, nonpolar anomalous, and nonpolar fresh. The influences on CPR caused by surface slope, rocks, and dielectric constant are analyzed quantitatively using high-resolution topography data and optical images. A two-component mixed model for CPR that consists of a normal surface and a rocky surface is developed to study the effect of rocks that are perched on lunar surface and buried in regolith. Our analyses show that inner wall of a typical bowl-shaped crater can give rise to a change of about 30 degrees in local incidence angle of radar wave, which can further result in a CPR difference of about 0.2. There is a strong correlation between Mini-RF CPR and rock abundance that is obtained from high-resolution optical images, and predictions from the two-component mixed model match well with the observed CPRs and the estimated rock abundances. Statistical results show that there is almost no apparent difference in CPR characteristics between the polar and nonpolar anomalous craters, or between the polar and nonpolar fresh craters. The enhanced CPR in the interior of anomalous craters is most probably caused by rocks that are perched on lunar surface or buried in regolith, instead of ice deposits as suggested in previous studies.