The Chinese Chang’E-7 (CE-7) mission is planned to land in the lunar south polar region, and then deploy a mini-flying probe to fly into the cold trap to detect the water ice. The selection of a landing site is crucial for ensuring both a safe landing and the successful achievement of its scientific objectives. This study presents a method for landing site selection in the challenging environment of the lunar south pole, utilizing multi-source remote sensing data. First, the likelihood of water ice in all cold traps within 85°S is assessed and prioritized using neutron spectrometer and hyperspectral data, with the most promising cold traps selected for sampling by CE-7’s mini-flying probe. Slope and illumination data are then used to screen feasible landing sites in the south polar region. Feasible landing sites near cold traps are aggregated into larger landing regions. Finally, high-resolution illumination maps, along with optical and radar images, are employed to refine the selection and identify the optimal landing sites. Six potential landing sites around the de Gerlache crater, an unnamed cold trap at (167.10°E, 88.71°S), Faustini crater, and Shackleton crater are proposed. It would be beneficial for CE-7 to prioritize mapping these sites post-launch using its high-resolution optical camera and radar for further detailed landing site investigation and evaluation.

One of the long-standing enigmas for lunar tectonic-thermal evolution is the spatiotemporal association of contractional wrinkle ridges and basaltic volcanism in a compressional regime. Here, we show that most of the 30 investigated volcanic (eruptive) centers are linked to contractional wrinkle ridges developed above preexisting basin basement-involved ring/rim normal faults. Based on the tectonic patterns associated with the basin formation and mass loading and considering that during the subsequent compression the stress was not purely isotropic, we hypothesize that tectonic inversion produced not only thrust faults but also reactivated structures with strike-slip and even extensional components, thus providing a valid mechanism for magma transport through fault planes during ridge faulting and folding of basaltic layers. Our findings suggest that lunar syn-tectonic mare emplacement along reactivated inherited faults provides important records of basin-scale structure-involved volcanism, which is more complex than previously considered.

Polarimetric synthetic aperture radar (SAR) provides an effective way to understand the physical properties of planetary surfaces. Rocks are the products of specific geological events, recording the evolution of impact craters on airless bodies. Multiple-scattered radar echoes from the surface or near-surface rocks generally exhibit high circular polarization ratio (CPR). In this paper, we systematically investigate the relationship between radar CPR and rock abundance of lunar regolith using Mini-RF SAR data. A total of 51 craters with diameters of 11.8-200 km are selected for analysis. The mean values of Mini-RF CPR and Diviner rock abundance are calculated for the interior and exterior of each crater. Statistical results show a close correlation between Mini-RF CPR and Diviner rock abundance, where high radar CPR and Diviner rock abundance are observed at the blocky ejecta. However, we find the difference of mean CPR value between crater interior and exterior is smaller than that of Diviner rock abundance. This may be attributed to the near surface rocks that contribute to radar CPR but are not considered in the inversion of Diviner rock abundance. Therefore, the concept of volumetric rock abundance is introduced, indicating the proportion of rocks with diameters larger than one-tenth of the radar wavelength within the detection area. A three component CPR model is then developed to link radar CPR to volumetric rock abundance. Furthermore, an inverse powerlaw relationship between volumetric rock abundance and crater ages is discovered, which further indicates the feasibility of using SAR data to estimate rock abundance of lunar regolith.

Mare domes (interpreted to be a type of shield volcano) represent one important endmember of a variety of volcanic edifices occurring across the volcanic plains on the Moon, whereas Ring‐Moat Dome Structures (RMDSs) are interpreted to reflect the thermodynamic behavior of plain‐forming mare flows during their emplacement and cooling. A comprehensive study of the direct association between mare domes and RMDSs can not only provide deep insights into their formation mechanisms but also yield key information on the nature of mantle sources. We characterized a total of 200 mare domes and more than 6,400 RMDSs within Mare Tranquillitatis using multiple sets of imagery and topography data. RMDS‐bearing domes (80 out of 200) are on average larger than those hosting no RMDSs (average diameter 10.2 vs. 5.5 km) and have lower height/diameter (H/D) ratios (0.01 vs. 0.02) and flank slopes (1.2° vs. 2°). We attribute the presence of RMDSs on some domes to be due to relatively higher effusion rates forming longer thinner flows, producing favorable conditions for the formation of RMDSs. The average diameter of the RMDSs on mare domes (226 m, n = 1,027) appears to be slightly smaller than those located in mare plains (256 m, n = 527). This may be due to slope effects and that the relatively thicker off‐dome part of flows undergoes a relatively higher degree inflation process, producing slightly larger RMDSs. We adapt the RMDS‐formation theoretical model to shallow subcrustal magma reservoir model to account for the Tranquillitatis dome‐RMDS associations.

Irregular mare patche (IMP) is one of the most enigmatic volcanic features in the lunar nearside maria. Their apparently fresh surface morphology and derived young model ages contradict the currently proposed thermal evolution history of the Moon. Lunar orbital synthetic aperture radar (SAR) data of Mini-RF onboard Lunar Reconnaissance Orbiter (LRO) and dual-frequency SAR (DFSAR) flying on Chandrayaan-2 are analyzed in this article, to constrain the properties of IMPs within some depth from a radar perspective. The SAR datasets are firstly orthorectified and co-registered with the optical images, which allow for the interpretation of different terrains in small IMPs. Then, the polarimetric and scattering characteristics of different IMP-associated terrains are extracted and analyzed. Results show that the higher mounds in Ina, Sosigenes and Cauchy-5, as well as the lower uneven units in Ina and Sosigenes IMPs might be covered by a layer of rock-poor materials, which is similar to the surrounding maria regolith. This layer can be as thick as > 0.6 m for the higher mounds and lower uneven units in Ina. Importantly, radar-bright IMPs are found, whose scattering characteristics are similar to these of the rocky units in Ina and the ejecta of degraded craters. Based on the radar characteristics of IMPs, their possible origins and evolution processes are discussed.

SAR data from the lunar spaceborne Reconnaissance Orbiter’s (LRO) Mini-RF and Chandrayaan-1’s Mini-SAR provide valuable insights into the properties of the lunar surface. However, public lunar SAR data products are not properly registered and are limited by localization issues. Existing registration methods for Earth SAR have proven to be inadequate in their robustness for lunar data registration. And current research on methods for lunar SAR has not yet focused on producing globally registered datasets. To solve these problems, this article introduces a robust automatic registration method tailored for S-band Level-1 Mini-RF and Mini-SAR data with the assistance of lunar DEM. A simulated SAR image based on real lunar DEM data is first generated to assist the registration work, and then an offset calculation approach based on normalized cross-correlation (NCC) and specific processing, including background removal, is proposed to achieve the registration between the simulated image, and the real image. When applying Mini-RF images and Mini-SAR images, high robustness and good accuracy are exhibited, which produces fully registered datasets. After processing using the proposed method, the average error between Mini-RF images and DEM references was reduced from approximately 3000 m to about 100 m. To further explore the additional improvement of the proposed method, the registered lunar SAR datasets are used for further analysis, including a review of the circular polarization ratio (CPR) characteristics of anomalous craters.