The Rümker region is located in the northern Oceanus Procellarum, which has been selected as the landing and sampling region for China’s Chang’e-5 (CE-5) mission. The thermophysical features of the mare units are studied in detail using the brightness temperature (TB) maps (TB, normalized TB, TB difference) derived from the CE-2 microwave radiometer data. The previously interpreted geological boundaries of the Rümker region are revisited in this study according to their TB behaviors: IR1, IR2, and IR3 Rümker plateau units are combined into one single unit (IR); and a hidden unit is found on the Mons Rümker; Mare basaltic units Im1 and Em1 are combined into Em1; and Em2 is more likely the extending of Im2. Each of the previous proposed landing sites and their scientific value are summarized and reevaluated. Based on this, four landing sites are recommended in order to maximize the scientific outcome of the CE-5 mission. We suggest that the Eratosthenian-aged Em4 and Em1 units as the top priority landing site for the CE-5 mission; the age-dating results will provide important clues concerning the thermal evolution of the Moon.

The internal structures are the key to understand the surface evolution of the Moon. However, the study of such kind is absent. In this study, the Chang'E-2 microwave radiometer data is employed to explore the internal structures in the highlands of the western lunar farside combined with the (FeO+TiO2) abundance data and the rock abundance data. The results are as follows. First, a new view on the cratering mechanism is proposed according to the brightness temperature (TB) performances and the estimated rock abundances in King, Bruno, and Necho craters. Second, the influential mechanism of the rocks on the TB is initially identified by the thermal anomalies at noon and night. Third, a special hidden hot anomaly centered at (109.4°E, 6.9°N) northwest to King crater is revealed by the 3.0 GHz map at noon and night, but its causes are still unclear. Fourth, the cause of the belt anomaly from Bruno crater to Necho crater is likely resulted from the impact ejecta of King crater. Finally, the highlands in the study area are divided into four units with distinct TB performances. Generally, the TB maps show a different view compared to the optical and thermal infrared data, which are important to improve understanding the surface evolution of the Moon.

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