Surface‐correlated nanophase iron particles (npFe⁰) alter the reflectance spectrum characteristics of airless bodies, thus making it an essential aspect of studying space weathering. Vapor deposition has been the only strongly proven npFe⁰ formation mechanism owing to the long exposure time of Apollo samples, whereas other formation mechanisms remain questioned. Newly returned younger Chang'E‐5 samples provide an opportunity to study the incipient formation mechanism of npFe⁰. Here, we combined transmission electron microscopy and electron energy loss spectroscopy to characterize the microscopic features of Chang'E‐5 olivine rims. The uppermost layer of these grains exhibits the simultaneous coexistence of npFe⁰ with Si‐rich material overlying an Mg‐rich layer, as well as numerous irregular vesicles containing oxygen‐rich (SiO and O₂) components embedded in the npFe⁰. These microscopic features collectively suggest subsolidus olivine decomposition during (micro)impact‐induced fragmentation or local heating processes, which may be the essential agent to alter the reflectance spectrum of airless bodies.

The Chang'e‐5 (CE‐5) materials represent the youngest returned lunar samples. We performed a detailed Raman spectroscopic survey (1259‐point Raman modal analysis) to evaluate the mineralogical characteristics of CE‐5 soils, constraining the source materials and shock effects of these unique samples. The mineral chemistry (e.g., Mg#_3‐60 for mafic minerals) and modal abundance (first distinguishing basaltic and feldspathic glasses) of CE‐5 mare soils are different from those of Apollo high‐ and low‐Ti basalts, possibly representing an intermediate‐Ti mare basalt. The occurrence of minor Mg‐rich materials (Mg# > 70) provides evidence of contamination from ∼5% to 7% exogenous materials, possibly related to Mg‐suite rocks. The microimage analyses suggest that the CE‐5 soils are fine‐grained, mature, and unimodal particle‐size distribution, highlighting that micrometeorite reworking dominates the CE‐5 regolith evolution with minor mixing from nonmare materials. The pressure‐sensitive minerals (quartz and maskelynite) indicate that 17–25.8 GPa shock pressures might be the higher limit in a relatively young lunar terrain.

Secondary impact craters, features created by projectiles ejected from a primary impact, contain important information about the primary cratering event and the nature and distribution of its ejecta. The Orientale impact basin (D ~ 930 km) is the youngest and the least degraded large impact basin on the Moon and has the most recognizable secondary impact craters. We identified and mapped 2,728 secondary craters in the investigated area of ~1.66 × 10⁷ km², covering an area from the rim of Orientale to six radii. Secondary crater diameters range from ~2 to 27 km, and the median diameter decreases as distance increases. Secondary craters are concentrated predominantly in the northwest and southwest. The ejecta deposit pattern inferred from secondary crater distribution suggests that the Orientale basin was formed by an oblique impact in which the downrange direction was 240°–265° in azimuth, and the incidence angle was steeper than 20°. The cumulative size‐frequency distribution of mapped secondary craters steepens as diameter increases and is very well approximated with a Weibull distribution with an exponent 1.32. A widely used crater scaling relationship predicts that the fragments that produced the secondary craters were predominantly in ~0.5–2‐km diameter range over the investigated area; the diameter of the largest fragment, however, decreases with increasing distance from Orientale. On the basis of the diameter of the largest secondary crater of Orientale, and other craters and basins, the largest secondary crater of the South Pole‐Aitken basin is estimated to be ~40 km in diameter. We explore the implications of these findings for the evolution of the megaregolith and future sample return missions.

The Vastitas Borealis Formation is a Hesperian-aged sedimentary unit that mainly covers the Martian northern plains. Its environment of formation is uncertain but may be related to an ancient Martian ocean, outflow channel deposits, compaction and drainage activities, or subsurface ice-related processes. Here we investigate the geological evolution of the Vastitas Borealis Formation using geochemical and mineralogical data acquired by the Mars Surface Composition Detector on board the Zhurong rover at the Tianwen-1 landing site. We find that the fine-grained soil is very similar to the ubiquitous surface dust at other landing sites on Mars but mixed with calcium-rich and magnesium-poor local materials. These materials are mostly igneous minerals mixed with allophane and imogolite/opal and appear to have a low degree of chemical alteration. We suggest that these deposits likely formed by alteration of extensive volcaniclastic soils in limited or ephemeral water under cold conditions, which largely supports the hypotheses of a frozen ocean and sublimation.