In December 2020, Chang’e-5 returned samples from mare basalt unit Em4/P58 in northern Oceanus Procellarum. With an absolute model age of 1.21-1.53 Ga (Hiesinger et al. 2003; Qian et al., 2018, 2021a). Elevation analysis of the interior of Rima Sharp and Mairan, plus geomorphological observations suggest lava backfilling of Rima Sharp with younger lava from Rima Mairan. Analysis of the magnetic field at the surface also shows that the younger lava from the southern Mairan vents, which covered the southeastern part of Em4/P58 is unmagnetized. Our new magnetic anomaly analysis shows that Em4/P58 unit can be divided into magnetized (northwest) and unmagnetized (southeast) parts. The comprehensive analysis of magnetic anomaly and topography shows that lava from southern rille is likely to have reached the Chang’e-5 landing site. Samples returned by Chang’e-5 will help constrain the source of lava flow and the evolution of the lunar magnetic field over time.

Chang’E-4, the first soft landing mission on the far side of the Moon, provided high-resolution close-range images up to 2.3 cm/pixel, especially suitable for the study of the degradation in the population of small-sized impact craters around the landing site. This paper presents a preliminary analysis of the population degradation mechanism of the small-sized impact craters. From mosaicked descent camera image, 6316 impact craters in the landing area were extracted, identified, and classified into four types according to their morphology: complete, slightly degraded, moderately degraded, and severely degraded craters. In-situ verification using the lander topographic camera image supported the crater degradation analysis around the landing site. The small-sized impact crater population equilibrium analysis was also carried out. Over 99% of the impact craters in the study area are in degradation, which suggesting the area is severely degraded. Our results suggest that similar to the findings for impact crater populations above the meter scale, the size of meter to centimeter scale impact craters is also strongly correlated with degradation, with smaller impact craters being more likely to degrade. Images from topographic cameras also confirm the severe degradation of small-scale craters. The crater populations in equilibrium of different resolutions areas shows that the cumulative SFD slope is contrary to previous research results, the smaller the size of the impact crater, the more difficult for them to achieve impact equilibrium, which due to secondary craters and the ground resurfacing caused by neighboring craters’ ejecta.

China’s first Mars Exploration Mission Tianwen-1 achieved full success. The loaded Zhurong Rover landed south of the Utopia Planita. The Tianwen-1 orbiter also sending back high-resolution images. We utilized the High-Resolution Imaging Camera (HiRIC) of Tianwen-1 and Context Camera loaded on the Mars Reconnaissance Orbiter to collect the image data and construct a 3D strata model of the Zhurong landing site. Using this model, we analyzed the material loss of ghost craters. Judging from the morphological characteristics of pitted cones at the Zhurong landing site, we confirmed their classification as mud volcanoes. We also analyzed the possible cause of formation by combining the gravity field and magnetic field data. The experimental results indicate that (1) the Zhurong landing site can be divided into the dry sedimentary, moisture sedimentary, and Vastitas boreal (VB) members as three strata and another ejecta blocks. The three strata are categorized into VB formations with an integral width of 1.2 km. (2) The cones at the Zhurong landing site are mud volcanoes formed by groundwater thermal activity, and the heat source originate from a southern underground magma chamber. The density of mud volcanoes signifies the existence of ejecta blocks. (3) Apart from volumetric compaction, some ghost craters show eruption of underground substances. Generally, after the VB unit located on the surface of the Zhurong landing site formed at 3.43 Ga, the current geomorphology of the landing site was altered due to the differentiation of water evaporation above ground and underground, underground thermal activity, and meteorite impacts.