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Knowing the structure of the crust is critical to understanding a planet's geologic evolution. Crustal thickness inversions rely on bulk density estimates, which are primarily affected by porosity. Due to the absence of high‐resolution gravity data, Mercury's crustal porosity has remained unknown. Here, we use a model that was calibrated to the Moon to relate Mercury's impact crater population and long‐wavelength crustal porosity in the cratered terrains. Therein, porosity is created by large impacts and then decreased as the surface ages due to pore compaction by smaller impacts and overburden pressure. Our models fit independent gravity‐derived porosity estimates in the northern regions, where data is well resolved. Porosity in the cratered terrains is found to be 9%–18% with an average and standard deviation of 13% ± $\pm $ 2%, indicating lunar‐like crustal bulk densities of 2,565 ± $\pm $ 70 kg m−3 ${\mathrm{m}}^{-3}$ from which updated crustal thickness maps are constructed. Plain Language Summary: The crust of a planet is a thermal barrier, which controls how fast heat escapes to space. Depending on its thickness, the crust can strongly insulate the planet's interior preventing efficient cooling. Therefore, knowing the structure of the crust is critical to unraveling the geologic history of planetary bodies. Crustal thickness is typically inverted from gravity and topography data. One critical parameter for these inversions is the bulk density of the crust, which is primarily driven by porosity variations. While high‐resolution gravity field mapping allowed constraining the bulk density and porosity of the lunar crust, crustal porosity on other planetary bodies has remained unknown. In this work, we use a model that was calibrated to the Moon to relate Mercury's impact crater population and long‐wavelength crustal porosity in the cratered terrains. We show that crustal porosity in the cratered terrains ranges from 9% to 18% with an average and standard deviation of 13% ± $\pm $ 2%, indicating lunar‐like low bulk densities of 2,565 ± $\pm $ 70 kg m−3 ${\mathrm{m}}^{-3}$. Key Points: Mercury's crustal porosity estimated from the crater population, assuming porosity formed by large impacts and decreased with surface agingCrustal porosity in the cratered terrains ranges from 9% to 18% with an average and standard deviation of 13% ± 2%The low bulk density of Mercury's crust in the cratered terrain, 2,565 ± 70 kg m−3, is similar to that of the lunar highlands [ABSTRACT FROM AUTHOR]

Lunar basaltic meteorite Asuka‐881757 (A‐881757), a member of the source crater paired YAMM meteorites (Yamato‐793169, A‐881757, Miller Range 05035 and Meteorite Hills 01210), provides information on potassium‐rare earth element‐phosphorous (KREEP)‐free magmatic sources within the Moon. Asuka‐881757 is an unbrecciated and Fe‐rich (Mg# 36) gabbro with coarse pyroxene (2–8 mm) and plagioclase (1–3 mm). The coarse pyroxene preserves mm‐scale, near‐complete hour‐glass sector zoning with strong Ca and Fe partitioning, similar to some Fe‐rich Apollo basalts. In contrast to the most Mg‐rich Apollo basalts, A‐881757 contains various types of symplectites (~8 vol%) formed by the breakdown of pyroxferroite due to slow cooling, resembling a few extreme Fe‐rich (Mg# ≤40) Apollo basalts. Petrographic observations and thermodynamic modeling suggest crystallizing in the order: Fe‐poor pyroxenes (Mg# 58–55) → co‐crystallized plagioclase and Fe‐rich pyroxenes (Mg# 49–20) → late‐stage assemblage including Fe‐augite, Fayalite, and Fe‐Ti oxides. Combining phase stability at variable P–T with petrographic observations, the minimum depth of formation of the A‐881757 parent magma can be constrained to between 60 and 100 km. KREEP‐free basalts (such as A‐881757 and the YAMM meteorites) originated from a relatively shallow mantle source and later underwent polybaric crystallization that occurred prior to eruption at the lunar surface. In contrast, the Apollo mare basalts mostly crystallized within lava flows from relatively deeper‐seated mantle sources. The crystallization of A‐881757 and other YAMM meteorites is unlike most Apollo basalts from the Procellarum KREEP terrane, and likely represent hidden cryptomare basalts close to lunar surface. [ABSTRACT FROM AUTHOR]

Lunar exploration and infrastructure development near the Moon's south pole, and at other future lunar settlements, demand a detailed understanding of the geotechnical properties, structure, composition, and stratigraphy of the near-surface lunar regolith. Long term exploration and development activities will require the use of regolith as a construction material for multiple structures, and as unrefined material for resource extraction during in situ resource utilization (ISRU) activities. Upcoming robotic and human exploration will be concentrated near the lunar south pole, which has a dominantly feldspathic composition typical of the lunar highlands. Past missions to lunar highlands terrain (Apollo 16, Luna 20) provide valuable "ground truth" data regarding the geomechanical properties of highlands regolith that serve as a guide for future exploration at the lunar south pole. Lunar highlands simulant LHS-1 has well-characterized geotechnical properties and is an appropriate analogue for highlands lunar regolith in terrestrial engineering studies. Cone penetrometer testing (CPT) measurements of LHS-1 reveal a strong exponential correlation between the G slope parameter and bulk density, which allows information to be obtained regarding the density profile of simulated regolith columns directly from CPT stress versus penetration curves. We show that LHS-1 can be used to replicate the near-surface regolith stratigraphy at the Apollo 16 highland landing region in Earth-based laboratories. The ultimate CPT penetration resistance measured in the laboratory under terrestrial gravity is not directly comparable to that measured under lunar gravity, and here we derive an average reduction factor of Rf = 0.29 to scale penetration resistance values to those measured in situ on the lunar surface. Geotechnical measurements of other lunar simulants combined with experiments similar to those described herein, tailored to the terrain type of interest, will provide crucial information to guide future regolith excavation, construction, and ISRU activities on the lunar surface. • LHS-1 lunar simulant is an appropriate geotechnical analogue for highlands regolith. • A strong correlation exists between CPT penetration resistance and regolith density. • Apollo 16 highlands regolith stratigraphy can be replicated on Earth using LHS-1. • Earth-based CPT values should be reduced by × 0.29 to adjust for lunar conditions. [ABSTRACT FROM AUTHOR]

One of the legacies of the Apollo missions and the fleet of unmanned probes that have followed them is the recognition that the Moon is far more active than previously believed, with seismic activity deep in the lunar interior and some tectonic activity at shallower depths, as well as gas release from below the surface. Here, we review lunar activity in the context of reports of the observation of transient lunar phenomena (TLPs), attempting to separate myth from reality. We suggest that a significant fraction of reported TLPs could have an explanation in local geology or geomorphology. In a further paper we will examine one particularly well-known TLP report to see if there is a plausible explanation based on local geology. [ABSTRACT FROM AUTHOR]

The lunar surface, which has been extensively explored and studied, offers valuable insights into its geological history and crater distribution due to the abundance of impact craters on its surface. Detecting numerous craters of different sizes on the lunar surface necessitated an automated process to avoid manual intervention, which consumed significant time and effort. However, traditional methods rely on manual feature extraction methods, encountering similar challenges, including low performance, particularly when confronted with diverse crater sizes and illumination conditions. In recent years, intelligent algorithms that introduce automated crater detection algorithms (CDAs) using deep learning (DL) techniques have played a vital role in detecting various sizes of craters on the lunar surface that may be missed or miss-classification by visual interpretation. This study outlines the challenges faced by traditional methods and explores recent advancements in DL techniques. The main objective is to provide a comprehensive review of prior studies, highlighting the advantages and limitations of each DL-based technique for automatic crater detection. Additionally, this study aggregates existing research on various image-processing tasks (such as semantic segmentation, classification-based, and object detection) utilizing DL-based techniques for detecting various sizes of craters on the lunar surface. Further, this study provides a comprehensive analysis of both manually and automatically compiled crater databases to assist new researchers in validating their models both qualitatively and quantitatively. By reviewing existing literature, this study aids new researchers in understanding the limitations and key findings of recent research, thereby promoting progress toward greater automation in crater detection. [ABSTRACT FROM AUTHOR]

One of the most common types of allochthonous impactite produced in hypervelocity impact events is impact breccia that contains melt particles. In numerous terrestrial hypervelocity impact structures such melt‐bearing breccias have been termed "suevite," after the type locality at the Ries impact structure, Germany. Despite its widespread occurrence, the origin, emplacement, and classification of suevite remains debated. In this contribution, we re‐examine the nature and origin of suevite at the Ries impact structure. The results of new field and laboratory investigations, when combined and synthesized with results from previous studies, lead to a multi‐stage model for the origin and emplacement of allochthonous impactites during the Ries impact event. Following the creation of a transient cavity the so‐called Bunte Breccia and "megablocks" were emplaced via ballistic sedimentation and subsequent radial flow during the excavation stage to form a continuous ejecta blanket. At the end of the excavation stage, a mixture of melt and lithic fragments formed a lining to the transient cavity and it is this material that later became the crater, dike, and outer suevite (OS) units. The crater suevite represents the material from the displaced zone of the transient cavity that was transported and mixed but never left the cavity. The emplacement of dike suevite occurred during the modification stage as the crater suevite was intruded into fractures in the underlying crater floor. The OS and rare impact melt rocks overlying the ballistic (Bunte Breccia) ejecta deposits were emplaced as outwards‐directed ground‐hugging flows largely during the modification stage of crater formation. The OS flows varied both spatially and temporally in terms of the flow characteristics, from being dominated by solid particles and gas (cf. pyroclastic density currents) to a mixture of solid particles, liquid (impact melt), and minor gases (i.e., particulate impact melt‐rich flows). These particulate impact melt‐rich flows dominated by far. Minor "fallback" of material from an ejecta plume is evidenced by accretionary lapilli in the Nördlingen 1973 core. In summary, allochthonous impactites at the Ries impact structure are not unusual but are consistent with observations from other terrestrial and planetary craters, where melt‐rich impactites overly ballistic ejecta deposits both outside and inside crater rims and where melt‐rich impactites occur in crater interiors. [ABSTRACT FROM AUTHOR]

Angle of repose is an important characteristic of lunar regolith, as it determines the slope stability of features such as hills and craters on the lunar surface and is useful for designing infrastructure and regolith conveyance and handling equipment. Using mineralogically accurate lunar regolith simulants LHS-1 and LHS-1D from Space Resource Technologies (SRT), the recent spin-off of the UCF Exolith Lab®, the relationship between angle of repose and aspects of the simulant, such as sample mass and particle size distribution, are explored. This study provides insight into what affects the angle of repose of lunar regolith, as well as how aspects of the regolith can be manipulated for in situ resource utilization and lunar construction applications. Through the manipulation of lunar regolith simulant particle size gradation and median particle diameter, it is possible to determine which aspects of particle size distribution most impact lunar regolith angle of repose. The results of this study indicate that while many characteristics of a regolith sample influence its angle of repose, the percentage of fines within a sample have the largest effect. [ABSTRACT FROM AUTHOR]

Rampart craters are a class of lakes or depressions in Titan's north polar region that have morphological attributes suggestive of an explosive origin. Two previous studies have proposed that rampart craters form via nitrogen or methane vapor explosions analogous to terrestrial maar explosions. We propose a new terrestrial analog for rampart craters: gas emission craters (GECs) found in permafrost zones. We evaluate the explosive origin of Titan's rampart craters by modeling the dispersal of material from an explosive vent. The dimensions of nine rampart craters with radar‐bright ramparts were used to model the explosion process. The model yields a range of explosion conditions (e.g., gas mass and reservoir depth) producing ejecta dispersal patterns matching the observed features. We find that gas masses of 1011–1014 kg are required to produce a rampart crater. We examine two explosion scenarios: (a) rapid, maar‐like vaporization and explosion of liquid nitrogen or methane, and (b) more gradual gas accumulation and explosion akin to a GEC driven by methane released from destabilizing clathrates. If Titan's crust is composed of pure water ice, the calculated gas pressures are consistent with a rapid, maar‐like explosion mechanism. If the subsurface is predominantly composed of organic materials or clathrate, either scenario may be plausible. Further research on the composition and tensile strength of Titan's subsurface are required to discriminate between hypotheses. Nevertheless, we conclude that explosive dispersal of ejecta from a vent can account for the morphologies of Titan's rampart craters and may contribute to atmospheric methane replenishment. Plain Language Summary: Rampart craters are lakes, filled or empty, in Titan's north polar region that appear to have formed via explosions. In this study, we use a numerical model and Cassini data to determine whether explosive release of subsurface pressurized gas can form rampart craters, and estimate the amount of gas required. We find that gas explosions sourced from the vaporization of liquid nitrogen or methane, or from methane released from within the ice crystal structure of methane clathrate, are capable of reproducing the observed shapes and dimensions of rampart craters. Large amounts of methane can be released in such explosions, replenishing Titan's diminishing atmospheric methane. Key Points: Explosive release of pressurized gas can form Titan's rampart cratersWe model maar‐like explosions driven by vaporization and gas emission crater‐like explosions driven by destabilized methane clathratesSignificant amounts of methane gas can be delivered to the atmosphere during the formation of a rampart crater [ABSTRACT FROM AUTHOR]

Venus preserves ∼1,000 impact craters, yet to date no impact basins larger than 300 km in diameter—common in the oldest terrains on Mercury, Mars and the Moon—are recognized on Venus. The tessera terrain is Venus' oldest recognized terrain. We describe a ∼1,500 km‐diameter concentric ring‐graben complex preserved on Haasttse‐baad Tessera, Venus that we identify as the Haasttse‐baad Tessera Ring Complex (HTRC). Based on geologic relations and numerical modeling, we propose that the HTRC may represent a Valhalla‐type multiring impact basin formed late during the evolution of its host ribbon‐tessera terrain (rtt). Formation of Valhalla‐type impact basins could involve a unique three‐layer target rheology with a thin elastic layer above a low viscosity layer above a deep strong layer. This multi‐layer rheological sandwich is consistent with crustal rheology previously proposed for the formation of Venus' rtt. If the HTRC is a Valhalla‐type impact basin, it would be Venus' oldest, and currently largest, impact structure, providing a rare window into Venus' ancient past and with implications for early crustal processes on Venus. Plain Language Summary: Venus preserves ∼1,000 impact craters, but no craters larger than 300 km—common on Mercury, Mars, and Moon—are recognized. We describe a large circular structure (∼1,500 km‐diameter) that formed on tessera terrain, Venus' oldest recognized surface type. The structure consists of concentric circular troughs that cut the tessera surface; geologic mapping shows that the structure formed late during tessera formation. We discuss the different mechanisms for forming large circular features marked by concentric rings of structures, and propose that it could be an example of a large impact basin named Valhalla‐type impact basin after a structure present in Jupiter's moon Callisto. Previous research suggests that the formation of these impact basins likely involves a distinctive layering in the impact site consisting of a sandwich of layers with different strengths (strong‐weak‐strong), a configuration previously proposed as necessary to form the host tessera terrain. Numerical models show that forming the circular structure as a Valhalla‐type impact basin is possible if a large meteorite crashes into this three‐layer crust. This unique structure, which might represent a very old and large impact structure, could provide a rare window into Venus' ancient past. Key Points: We describe a unique ∼1,500 km‐diameter concentric ring complex and present detailed geologic maps of the structure and its host tesseraWe propose that this structure may represent a Valhalla‐type impact structure, as supported by geologic mapping and numerical modelingIf the hypothesis is valid, the complex is the largest impact structure recognized on Venus, with implications for early planet processes [ABSTRACT FROM AUTHOR]

Rock abundances on the Moon represent both an opportunity to understand the history of the surface and of the regolith and a hazard to lander missions. While rock erasure by meteoroid bombardment is known to modify rock size˗frequency distributions, the interplay between rock erasure and rock exposure by impact cratering, and the resulting net rock abundance, is not known. Leveraging a coupling between modeling and optical imagery from the lunar orbit, we calculate new rock lifetimes that consider the specific shattering energy and the fragments produced by boulder shattering. We find differences between the estimated and expected specific shattering energy (Qs*), likely suggesting incomplete understanding of the scaling of the shattering energy with velocity and size. We find that the decrease in rock abundances with time on crater ejecta occurs faster than previous estimates based on thermal infrared data. Plain Language Summary: The surface of the Moon is littered with floating rocks ranging in size from centimeters to decameters. These rootless rocks are formed by impact cratering and are reduced to fine grained soil through fragmentation by meteoroid bombardment. Here we combine a model of rock formation and fragmentation with measurements of rock sizes extracted from images obtained from an orbiting spacecraft. We look at the effects of repeated fragmentation events. This gives us a better idea of the energy required for rock erasure as well as the abundance of centimeter‐scale rocks. We obtain an improved estimate of the time it takes for rocks to produce soil around impact craters. Key Points: The specific shattering energy of lunar boulders is estimatedThe decrease in rock abundance with time is modeled around impact cratersThe rock size‐frequency distribution covering the decameter to centimeter scale is modeled [ABSTRACT FROM AUTHOR]

Linear gravity anomalies (LGAs) on the Moon have been interpreted as ancient magmatic intrusions formed during the lunar expansion. The composition of such ancient subsurface intrusions may offer hints for the lunar thermodynamic state in the initial stage of lunar history. To pose a first compositional constraint on magmatism related to lunar expansion, this study analyzed the spectrum and gravity around craters on LGAs, such as Rowland, Roche, and Edison craters. Using reflectance spectra around the craters, we first surveyed non‐mare basaltic exposures. To test the LGA excavation scenario as a possible origin of the discovered exposures, we then compared the Gravity Recovery and Interior Laboratory data and post‐cratering gravity simulation with the iSALE shock physics code. Our spectral analysis reveals no basaltic exposure around the Rowland crater. Further, the observed termination of LGA at the crater rim contradicts the gravity simulation, which assumes that LGA predates the Rowland crater. These results suggest that LGA formation might postdate the Rowland formation and that lunar expansion lasted even after the Nectarian age. On the other hand, we found that both Roche and Edison craters possess basaltic exposures in their peripheries. Because the gravity reduction inside Roche crater can be reproduced in our simulation, the discovered basaltic exposures are possibly LGA materials ejected from these craters. The composition of those exposures shows that the LGA intrusions at the two locations are composed of low‐titanium magma, indicating that ancient magma during the expansion did not contain ilmenite‐rich melt, perhaps resulting from the low‐ilmenite content of the ancient upper mantle. Plain Language Summary: The Moon has positive, narrow, and long gravity anomalies, so‐called linear gravity anomalies (LGAs), which are thought to be magmatic intrusions formed during the ancient lunar expansion. The composition of these intrusions may provide insights into the early lunar thermal state. This study analyzed the reflectance spectra and gravity data around craters located on LGAs, specifically Rowland, Roche, and Edison craters, which are postulated to have ejected the LGA material. By analyzing the reflectance spectra, we first identified non‐mare basaltic exposures that likely originated from these subsurface formations. We next examine if these exposures are composed of the LGA materials by comparing the observed gravity with cratering simulation results. We found no basaltic exposures around Rowland and that gravity inside Rowland is not consistent with the excavation hypothesis, perhaps suggesting that LGA formation and lunar expansion occurred after the Rowland formation. On the other hand, we discovered basaltic exposures around both Roche and Edison craters, which can be interpreted as ejecta from the LGAs consistent with the gravity inside Roche crater. The composition of these exposures indicates that LGAs are composed of low‐titanium magma, which provides a new constraint on the ancient thermal state of the Moon. Key Points: High‐calcium pyroxene exposures and gravity reduction around Roche crater imply an excavation of lunar linear gravity anomaly materialsLunar subsurface dikes formed during the ancient expansion stage are estimated to be composed of low‐titanium magmaA linear gravity anomaly possibly postdates the Rowland crater, suggesting a potential prolongation of lunar expansion beyond the Nectarian age [ABSTRACT FROM AUTHOR]

The lunar surface contains a wide variety of topographic shapes and features, each with different distributions and scales, and any analysis technique to objectively measure roughness must respect these qualities. Coarse‐graining is a naturally scale‐dependent filtering technique that preserves scale‐dependent symmetries and produces coarse elevation maps that gradually erase the smaller features from the original topography. In this study of the lunar surface, we present two surface variability metrics obtained from coarse‐graining lunar topography: fine elevation and coarse curvature. Both metrics are isotropic, deterministic, slope‐independent, and coordinate‐agnostic. Fine (detrended) elevation is acquired by subtracting the coarse elevation from the original topography and contains features that are smaller than the coarse‐graining length‐scale. Coarse curvature is the Laplacian of coarsened topography, and naturally quantifies the curvature at any scale and indicates whether a location is elevated or depressed relative to its neighborhood at that scale. We find that highlands and maria have distinct roughness characteristics at all length‐scales. Our topographic spectra reveal four scale‐breaks that mark characteristic shifts in surface roughness: 100, 300, 1,000, and 4,000 km. Comparing fine elevation distributions between maria and highlands, we show that maria fine elevation is biased toward smaller‐magnitude elevations and that the maria–highland discrepancies are more pronounced at larger length‐scales. We also provide local examples of selected regions to demonstrate that these metrics can successfully distinguish geological features of different length‐scales. Plain Language Summary: Planetary surface roughness is inherently scale‐dependent: a seemingly smooth surface can look rough if you zoom in enough. The converse can also hold: small‐scale rough features can look smooth if you zoom out enough. Therefore, it is important to have a way to measure surface roughness that accounts for variations in how "zoomed in" we are looking. In this work we use coarse‐graining, an approach that effectively blurs the lunar surface, allowing us to vary the "zoom" level as we are measuring surface variability. We present two ways of measuring the scale‐dependent variability of the lunar surface: coarse curvature (measures how curved the blurred surface is) and fine elevation (looks at everything that was removed by the blurring, and measures how much those smaller features contributed to the topography). Using our approach, we are able to incrementally change what is considered "small" and measure how the perception of the lunar surface changes as we are gradually zooming out of it. Our results highlight the dichotomy in roughness between the lunar maria and highlands. We also identify four key length‐scales where the roughness changes qualitatively, suggesting a change in the underlying physical processes that contribute to different kinds of roughness. Key Points: Two novel metrics for surface variability display distinct characteristics for highlands, maria, and various geological featuresTopographic spectra spanning 1–5,000 km identify four roughness characteristic changes that correlate with known crater distributionsFrequencies of fine elevation highlight and contrast scale‐ and terrain‐dependent behaviors between mare and highlands regions [ABSTRACT FROM AUTHOR]

The Lunar CRater Observations and Sensing Satellite (LCROSS) impacted a Centaur rocket stage into a permanently shadowed region (PSR) in Cabeus crater, excavating water ice and other volatiles. We used the Miniature Radio Frequency (Mini‐RF) instrument on the Lunar Reconnaissance Orbiter and the ShadowCam instrument on the Korean Pathfinder Lunar Orbiter to detect the probable 22‐m diameter crater that resulted from the LCROSS impact. The crater formed superposed upon a dense small crater population along a crater ray from a larger pre‐existing crater. From its geologic context, the ice and regolith excavated by LCROSS were likely modified within the last 0.1–0.5 Gyr. An upper limit for the excavated volatiles is ~0.9 Gyr, as the location was not a PSR prior to that time. A young age for the LCROSS‐detected volatiles supports the idea that they were mostly emplaced by an exogenic mechanism, such as from comets or the solar wind. Plain Language Summary: The LCROSS experiment formed an impact crater in an area of permanent shadow on the Moon, striking the surface at 2.5 km/s with a 2,300 kg spent rocket body on 9 October 2009. The impact ejecta from this cratering event included detectable amounts of water and other volatiles, which is perhaps the most direct evidence for significant water deposits on the Moon. However, since the impact location is in permanent shadow (no direct solar illumination), it proved hard to observe definitively the crater that LCROSS formed. Here, we use data from Mini‐RF, which illuminated the surface with S‐band radar, combined with ShadowCam, which acquires images within permanent shadows, to find the probable LCROSS impact crater. The impact crater is 22‐m in diameter, a bit smaller than was inferred indirectly after LCROSS. We also present new evidence that the volatiles in the ejecta likely got there in the last 20% of lunar history, which is important for understanding their origin and evolution. Key Points: We used Mini‐RF and ShadowCam to locate the 22‐m crater formed by LCROSS within a permanently shadowed region near the Moon's south poleGiven the crater's size, the regolith that was excavated, including volatiles, likely came from approximately the upper 2 mThe geologic context of the LCROSS crater suggests that the volatiles it excavated were relatively young, from the Copernican epoch [ABSTRACT FROM AUTHOR]

Magnetite is rare on the Moon. The ubiquitous presence of magnetite in lunar soil has been hypothesized in previous Apollo Mössbauer spectroscopy and electron spin resonance studies, but there is currently no mineralogical evidence to prove it. Here, we report a large number of submicroscopic magnetite particles embedded within iron-sulfide on the surface of Chang'e-5 glass, with a close positive correlation between magnetite content and the TiO2 content of the surrounding glass. The morphology and mineralogy of the iron-sulfide grains suggest that these magnetite particles formed via an impact process between iron-sulfide droplets and silicate glass melt, and ilmenite is necessary for magnetite formation. Magnetite in lunar glass is a potential candidate for the "magnetite-like" phase detected in the Apollo era and suggests that impact-induced submicroscopic magnetite may be ubiquitous in high-Ti regions of the Moon. Moreover, these impact-induced magnetite particles may be crucial for understanding the lunar magnetic anomalies and mineral components of the deep Moon. [ABSTRACT FROM AUTHOR]

Depleted shergottites record unique information about the primary composition and differentiation of the mantle of Mars. Their petrology, geochemistry, and cosmic ray exposure and crystallization ages suggest that most of them were excavated by a single young impact in the Amazonian‐aged lava flows of the Tharsis and Elysium volcanic provinces. However, the difficulties of deriving consistent model ages for individual craters and inadequate evaluation of 3‐7 km craters capable of ejecting martian meteorites have not been settled. Here we perform detailed geological investigations and crater statistics in patches of impact melt deposits for potential source craters of depleted shergottites with D > 3 km, especially those in the Tharsis and Elysium volcanic provinces. By excluding the effect of heterogeneous textures across ejecta deposits, which hinder straightforward extraction of superposed production populations, our systematically updated model ages reveal that Chakpar crater at the northern flank of Ascraeus Mons is the best‐fit candidate. The local context of this crater permits establishing a link between the meteorites and specific lava flows. The long‐lived volcanic center here may experience an eruption and/or local deposition hiatus for about 1.8 billion years, and abundant subsurface water existed when the impact occurred at about 1.1 million years. [ABSTRACT FROM AUTHOR]

Lunar regolith is the most abundant resource on the lunar surface, which can be used for in-situ fabrication and repair technologies. Vat photopolymerization-based additive manufacturing is among the most promising techniques, capable of producing precise ceramic parts of complex shapes from the lunar regolith feedstock for the needs of future crewed exploration missions to the Moon. One of the under-studied aspects of additive manufacturing with lunar regolith is the pre-and post-treatment procedures, which would ensure optimal energy and material consumption and the best printing performance. The goal of the present article was to define the influence of the mineral composition of lunar regolith simulants and the parameters of their pre-processing on the properties of sintered regolith ceramics. It was found that the highland regolith could be sintered to higher relative density compared to the mare regolith. The optimal sintering temperature was determined to be 1150 °C for both types of lunar regolith. An optimal mineral and fractional composition for the regolith feedstock was determined based on the trade-off analysis between lunar regolith sinterability and its printability via vat photopolymerization-based additive manufacturing. Vat-polymerization was performed to produce complex-shaped ceramic parts, yielding 95 % of relative density and a mean ultimate flexural strength of 106 ± 5 MPa, confirming the proposed trade-off point. [ABSTRACT FROM AUTHOR]

There is extensive geologic evidence of ancient volcanic activity on the Moon, but it is unclear how long that volcanism persisted. Magma fountains produce volcanic glasses, which have previously been found in samples of the Moon’s surface. We investigated ~3000 glass beads in lunar soil samples collected by the Chang’e-5 mission and identified three as having a volcanic origin on the basis of their textures, chemical compositions, and sulfur isotopes. Uranium-lead dating of the three volcanic glass beads shows that they formed 123 ± 15 million years ago. We measured high abundances of rare earth elements and thorium in these volcanic glass beads, which could indicate that such recent volcanism was related to local enrichment of heat-generating elements in the mantle sources of the magma. [ABSTRACT FROM AUTHOR]

This article explores the contributions of Italian astronomers to planetary astronomy, highlighting the discoveries and observations made by figures such as Galileo Galilei, Giovanni Domenico Cassini, Francesco Bianchini, Giuseppe Piazzi, Francesco de Vico, Angelo Secchi, and Giovanni Schiaparelli. It discusses Galileo's telescopes, Schiaparelli's work on Mars, Piazzi's discovery of Ceres, and Secchi's spectroscopic observations. The article also addresses the neglect of Italian contributions in the field and aims to rectify this by providing informative chapters on various Italian astronomers. However, there are concerns about the accuracy and tone of certain chapters. The text specifically focuses on Giuseppe Piazzi and his discovery of Ceres, discussing the challenges he faced and the controversy surrounding his decision to keep the discovery a secret. It also touches on the role of Catholic priests in astronomy and the challenges faced by Italian astronomers compared to those in other countries. Overall, the article provides an interesting and informative perspective on the history of astronomy. [Extracted from the article]

The lunar surface undergoes various space weathering and impact processes, which shape the regolith and expose boulders. Using high-resolution Lunar Reconnaissance Orbiter (LRO) Narrow Angle Camera imagery and associated Digital Elevation Models, we investigate regolith thicknesses and boulder densities at the four candidate landing sites of the Emirates Lunar Mission Rashid-1 rover: the floor-fractured crater Atlas and the Sinus Iridum, Oceanus Procellarum and Lacus Somniorum maria. The regolith thickness is estimated using the small crater morphology method, by mapping 3413 central mound, flat-bottomed, concentric craters (<350 m in diameter). Boulders were counted manually and compared with LRO Diviner rock abundance and mini-RF Circular Polarisation Ratio global maps. There is no obvious correlation between the site's age, average regolith thickness and boulder density. The "Depth-Age hypothesis" is not confirmed here: Atlas (3.8 Gyr) has the thinnest regolith (median: 1.2 m), Procellarum (1.9 Gyr) and Somniorum (3.7 Gyr) have similar thicknesses (1.7 m and 1.8 m respectively), and the regolith in Iridum (3.4 Gyr) is the thickest (2.9 m). The estimated regolith thickness is highly variable laterally within the landing ellipses. Boulder fields in the landing areas are well-correlated with higher Diviner rock abundance values, and with locally thicker patches of regolith. The relatively thin regolith in Atlas could be related to its complex geology involving multiple volcanic episodes. Orbital estimates of regolith thickness and boulder distribution remain key for landing safety and trafficability assessments during mission preparations, and bring key insights into the local history of the regolith through crater morphologies. [ABSTRACT FROM AUTHOR]

The physical properties of lunar regolith are crucial for exploration planning, hazard assessment, and characterizing scientific targets at global and polar scales. The dielectric constant, a key property, offers insights into lunar material distribution within the regolith and serves as a proxy for identifying volatile-rich regoliths. Miniature radio frequency (Mini-RF) on the Lunar Reconnaissance Orbiter (LRO) provides a potential tool for mapping the lunar regolith's physical nature and assessing the lunar volatile repository. This study presents global and polar S-band Mini-RF dielectric signatures of the Moon, obtained through a novel deep learning inversion model applied to Mini-RF mosaics. We achieved good agreement between training and testing of the model, yielding a coefficient of determination (R2 value) of 0.97 and a mean squared error of 0.27 for the dielectric constant. Significant variability in the dielectric constant is observed globally, with high-Ti mare basalts exhibiting lower values than low-Ti highland materials. However, discernibility between the South Pole–Aitken (SPA) basin and highlands is not evident. Despite similar dielectric constants on average, notable spatial variations exist within the south and north polar regions, influenced by crater ejecta, permanently shadowed regions, and crater floors. These dielectric differences are attributed to extensive mantling of lunar materials, impact cratering processes, and ilmenite content. Using the east- and west-looking polar mosaics, we estimated an uncertainty (standard deviation) of 1.01 in the real part and 0.03 in the imaginary part of the dielectric constant due to look direction. Additionally, modeling highlights radar backscatter sensitivity to incidence angle and dielectric constant at the Mini-RF wavelength. The dielectric constant maps provide a new and unique perspective of lunar terrains that could play an important role in characterizing lunar resources in future targeted human and robotic exploration of the Moon. [ABSTRACT FROM AUTHOR]

Silicic lithologies on planetary surfaces indicate magmatic evolutionary processes in their interiors. The Wolf crater complex within Mare Nubium on the Moon is one such silicic construct associated with a high thorium anomaly. This study integrates morphological, compositional, chronological and gravity anomaly analyses of high‐resolution data from various lunar missions to establish this construct as a silicic volcanic caldera. Lobate flows with steeply sloping fronts indicate that the crater rims comprise high‐viscosity silicic lavas, while the structurally controlled inner crater walls suggest caldera collapse triggered by magma depletion. In the crater rims, low Christiansen Feature position values reaffirm the presence of silicic lithologies, consistent with the low gravity anomaly signature beneath the complex, while spectroscopic data reveal low mafic mineral abundances and negligible hydration features. Chronological analyses yield silicic volcanism ages coeval with surrounding mare basalts (3.8–3.6 Ga), while intra‐caldera basalts have 2.36–2.02 Ga ages, indicating prolonged magmatism in this region. Melting of suitable crustal protoliths like alkali gabbronorite/monzogabbro/troctolite by basaltic underplating is inferred to have generated silicic magmas that formed the Wolf volcanic complex, instead of basaltic magma fractionation or silicate‐liquid immiscibility processes. Large impacts during the Late Heavy Bombardment may have enhanced partial melting of the mantle and created crustal fractures that facilitated the ascent of viscous silicic melts through the lunar crust. Contemporaneous existence of suitable protoliths and adequate crustal pathways for magma ascent may have controlled silicic volcanism on the Moon, and can explain the sporadic occurrence and overlapping ages of the lunar silicic constructs. Plain Language Summary: Understanding how evolved silica‐rich rocks formed on the Moon can shed light on the magmatic differentiation and thermal evolution of the lunar mantle. Here, we study one such silicic region called the Wolf crater complex on the lunar nearside using compositional and morphological evidence from high‐resolution images and remotely sensed data. Spectroscopic and gravity studies confirm that the rocks have a silicic composition but with negligible water content. The complex is characterized as a silicic volcanic crater/caldera that was later filled with basalt. Formation of the volcano and its collapse to form the caldera were controlled by pre‐existing structures. Ages calculated by crater‐counting methods suggest that magmatic activity persisted in this region for ∼2 billion years. These apparently dry silicic melts could not have been derived by fractionation or unmixing of basaltic magmas. Instead, large impacts in the region may have thinned the crust, enhancing partial melting of the underlying mantle and facilitating basaltic underplating of the crust. Melting of appropriate protoliths (alkali gabbronorite/monzogabbro/troctolite), where present in the underplated crust, may generate viscous silicic melts whose ascent is then facilitated by impact‐generated fractures. This model explains why lunar silicic constructs are rare and have ages broadly synchronous with the Late Heavy Bombardment. Key Points: The Wolf crater complex is a volcanic caldera where silicic volcanism occurred between ∼3.6–3.7 Ga, followed by mafic volcanism till ∼2.02 GaStructural trends imposed by regional pre‐existing fracture systems facilitated both melt eruption and caldera collapseNear anhydrous melting of appropriate crustal protoliths caused by basaltic underplating generated the silicic melts [ABSTRACT FROM AUTHOR]

The toolbox to study the Universe grew on 14 September 2015 when the LIGO–Virgo collaboration heard a signal from two colliding black holes between 30 and 250 Hz. Since then, many more gravitational waves have been detected as detectors continue to increase sensitivity. However, the current and future interferometric detectors will never be able to detect gravitational waves below a few Hz due to oceanic activity on Earth. An interferometric space mission, the laser interferometer space antenna, will operate between 1 mHz and 0.1 Hz, leaving a gap in the decihertz band. To detect gravitational-wave signals also between 0.1 and 1 Hz, the Lunar Gravitational-wave Antenna will use an array of seismic stations. The seismic array will be deployed in a permanently shadowed crater on the lunar south pole, which provides stable ambient temperatures below 40 K. A cryogenic superconducting inertial sensor is under development that aims for fm/ √ Hz sensitivity or better down to several hundred mHz, and thermal noise limited below that value. Given the 10 6 m size of the Moon, strain sensitivities below 10 − 20 1/ √ Hz can be achieved. The additional cooling is proposed depending on the used superconductor technology. The inertial sensors in the seismic stations aim to make a differential measurement between the elastic response of the Moon and the inertial sensor proof-mass motion induced by gravitational waves. Here, we describe the current state of research toward the inertial sensor, its applications, and additional auxiliary technologies in the payload of the lunar gravitational-wave detection mission. [ABSTRACT FROM AUTHOR]

• We used LROC-NAC images to derive the meter scale morphological features of Petavius crater on the Moon. • We identified various morphological features near the central peak, including boulders, exposed outcrops, layering, fresh craters, rilles, and shields. • Our CSFD analysis indicates that magmatic activity likely persisted for ∼2.75 Ga in the Petavius crater. • The morphological and tectonic features on the floor of the crater were the result of post-impact processes. Petavius, a complex crater from the late Imbrian epoch, features a giant central peak, numerous smaller peaks, and an inner terraced wall arising nearly 3 km above the crater floor. The region has seen periods of tectonic and volcanic activity. A meter-scale detailed mapping of LROC- Narrow Angle Camera (NAC) images was carried out to understand the tectonic features and associated volcanic history under this crater. We found many fragmented blocks, fields of striated boulders, grabens, layering near grabens and striated boulders, rock exposures, and many fractures from NAC mapping, indicating magma creating pressure underneath the floor of a crater. The fractures identified from NAC images are probably linked with an underlying magmatic sill of high-density bodies. Crater size-frequency distribution analysis indicates that magmatic activity likely persisted for ∼2.75 Ga in the Petavius crater. It is noteworthy that this relatively recent age of volcanism has not been reported previously. The crustal thickness of the study region varies from 27 to 40 km; at the mapped tectonic features and volcanic regions, the crustal thickness of 30–34 km is found. The unique tectonic environment of the Petavius crater, in combination with the associated morphological variation and numerous exposures of mafic, suggests that the crater formed in phases associated with its structural and morphologic features and is derived from the lower crust. The morphometric analysis and previous studies support a model of magmatic intrusion and sill formation within the fractured crust beneath the crater floor; such a sill would be a likely source both for effusive mare material erupted through floor fractures into low-lying portions of the crater floor. The tectonic system on the floor of the crater was the result of post-impact processes. [ABSTRACT FROM AUTHOR]

The article presents the results of the analysis of data from the Russian neutron spectrometer LEND (Lunar Exploration Neutron Detector), installed aboard NASA's lunar orbiter LRO (Lunar Reconnaissance Orbiter). An estimate of the content of subsurface water ice in the permanently shadowed region Cabeus-1, located inside the large Cabeus crater in the vicinity of the lunar south pole, has been obtained. The analysis used observations made with the LEND instrument from 2009 to 2023. It is shown that the surface neutron albedo in the vicinity and inside of Cabeus-1 correlates with the relief height and the distribution of average annual temperatures. The average subsurface water ice content over the entire Cabeus-1 region was estimated to be 0.49 ± 0.05% by mass fraction. The maximum value of about 0.7% is observed at the very bottom of the crater on the surface area where the minimum average annual temperature was recorded. This site coincides with the site of the LCROSS (Lunar Crater Observation and Sensing Satellite) impact experiment, which confirmed a significant amount of water ice in the near-surface material of the Moon. [ABSTRACT FROM AUTHOR]

This article explores the influence of lunar regolith and rover structure, such as mast design and material composition, on antenna parameters. It focuses on the distinctive difficulties of communication in the lunar environment, which need specialized antenna solutions. This study specifically examines the performance of antennas on the lunar Rashid rover within the Atlas crater, a landing site on the moon, considering two antenna types: a sleeve dipole antenna and an all-metal patch antenna. Thermal analyses reveal temperatures in the Atlas crater can exceed 80 °C during lunar mid-day. The findings highlight the effect of different materials used as thermal coatings for Rashid rover antennas, as well as the influence of rover materials on antenna performance. Furthermore, this study extends to analyze the conductivity and depth of lunar regolith within the Atlas crater. Given the critical role of antennas in wireless communication, understanding how lunar regolith properties affect antenna performance is essential. This research contributes to the creation of a strong communication system for the Rashid rover and future lunar missions by considering the features of the lunar regolith in addition to the rover's size and material attributes. [ABSTRACT FROM AUTHOR]

Impact craters are crucial for our understanding of planetary resources, geological ages, and the history of evolution. We designed a novel pseudo-spectral spatial feature extraction and enhanced fusion (PSEF) method with the YOLO network to address the problems encountered during the detection of the numerous and densely distributed meter-sized impact craters on the lunar surface. The illumination incidence edge features, isotropic edge features, and eigen frequency features are extracted by Sobel filtering, LoG filtering, and frequency domain bandpass filtering, respectively. Then, the PSEF images are created by pseudo-spectral spatial techniques to preserve additional details from the original DOM data. Moreover, we conducted experiments using the DES method to optimize the post-processing parameters of the models, thereby determining the parameter ranges for practical deployment. Compared with the Basal model, the PSEF model exhibited superior performance, as indicated by multiple measurement metrics, including the precision, recall, F1-score, mAP, and robustness, etc. Additionally, a statistical analysis of the error metrics of the predicted bounding boxes shows that the PSEF model performance is excellent in predicting the size, shape, and location of impact craters. These advancements offer a more accurate and consistent method to detect the meter-sized craters on planetary surfaces, providing crucial support for the exploration and study of celestial bodies in our solar system. [ABSTRACT FROM AUTHOR]

The Gardner region is a well‐known shield volcanic complex on the Moon. Its magma origin and formation mechanism are of significant interest but still enigmatic. To reveal the subsurface structure of this volcanic complex, we propose a new 3‐D inversion method of the gravity field based on the regularizations of the L1 norm of the model and its gradients. The model test indicates that our proposed method can recover the density structures with high resolution. Subsequently, we apply it to the Bouguer gravity data in the Gardner region. Our result shows a large, dense body with a volume of about 45 × 45 × 13 km3 centered under the topographic bulge of the Gardner Plateau. We infer that this structure is most likely dense basalts trapped at the crust‐mantle boundary as a sill and acted as the magma reservoir that has fed the volcanic complex in the Gardner area. Plain Language Summary: Volcanism is common on the Moon, which provides an important window into its topography and thermal evolution. The surface topography of the Gardner region displays a series of small shield‐like domes, sinuous rilles, and irregular depressions. It has been identified as one of the eight large volcanic complexes on the Moon. However, little is known about its internal structure, and many speculations exist about its formation. Gravity observation is one of the important means to probe the inner structure. In the Gardner area, a distinct quasi‐circular positive Bouguer gravity anomaly is observed, indicating the presence of subsurface mass surplus. Exploring the cause of the gravity anomaly can provide a basis for revealing the origin of volcanism in this area. However, due to the non‐uniqueness of potential field interpretation, available inversion methods of large‐scale gravity data face the problem of low‐depth resolution. In order to reveal the deep structure of the Gardner area, a new gravity inversion method is developed and applied. The results reveal a large, dense, sill‐like structure under the Gardner plateau. It is very likely the magmatic reservoir of the large shield volcanic complex, which provides profound evidence for confirming the volcanic structure of the Gardner region. Key Points: A new inversion method of the gravity field based on the regularizations of the L1 norm of the model and its gradients is proposedThe practical inversion reveals a large dense sill at the 9–22 km depth centered under the lunar Gardner volcanic complexThe estimated dense sill is most likely the magma chamber of the large shield volcanic structure in the Gardner region [ABSTRACT FROM AUTHOR]

The study of extremophilic microorganisms has sparked interest in understanding extraterrestrial microbial life. Such organisms are fundamental for investigating life forms on Saturn's icy moons, such as Enceladus, which is characterized by potentially habitable saline and alkaline niches. Our study focused on the salt-alkaline soil of the Al Wahbah crater in Saudi Arabia, where we identified microorganisms that could be used as biological models to understand potential life on Enceladus. The search involved isolating 48 bacterial strains, sequencing the genomes of two thermo-haloalkaliphilic strains, and characterizing them for astrobiological application. A deeper understanding of the genetic composition and functional capabilities of the two novel strains of Halalkalibacterium halodurans provided valuable insights into their survival strategies and the presence of coding genes and pathways related to adaptations to environmental stressors. We also used mass spectrometry with a molecular network approach, highlighting various classes of molecules, such as phospholipids and nonproteinogenic amino acids, as potential biosignatures. These are essential features for understanding life's adaptability under extreme conditions and could be used as targets for biosignatures in upcoming missions exploring Enceladus' orbit. Furthermore, our study reinforces the need to look at new extreme environments on Earth that might contribute to the astrobiology field. [ABSTRACT FROM AUTHOR]

The Moon has a tenuous atmosphere produced by space weathering. The short-lived nature of the atoms surrounding the Moon necessitates continuous replenishment from lunar regolith through mechanisms such as micrometeorite impacts, ion sputtering, and photon-stimulated desorption. Despite advances, previous remote sensing and space mission data have not conclusively disentangled the contributions of these processes. Using high-precision potassium (K) and rubidium (Rb) isotopic analyses of lunar soils from the Apollo missions, our study sheds light on the lunar surface-atmosphere evolution over billions of years. The observed correlation between K and Rb isotopic ratios (d 87Rb = 0.17 d 41K) indicates that, over long timescales, micrometeorite impact vaporization is the primary source of atoms in the lunar atmosphere. [ABSTRACT FROM AUTHOR]

A comparative study of impact glasses from the Lonar crater, located on the Deccan basalt plateau, India, and impact glasses from lunar regolith delivered by the Soviet automatic stations (AS) Luna-16 and Luna-24 (Sea of Plenty and Sea of Crises) was carried out. Numerous natural alloys (Cu3Ni2, Ni2Cu and Ni3Cu) that were previously unknown in nature were discovered in the impactites of the Lonar crater and the regolith of the Moon. The discovery of such alloys expands the area of isomorphism in the Cu–Ni system. As a result of a comparison of impactites of the Earth and the Moon, similarities were discovered in the composition, size and morphology of particles of copper–nickel alloys, which may be an indicator of impact processes. One of the possible mechanisms for the formation of Ni–Cu particles was condensation from a gas–plasma cloud. A possible source of material for Cu–Ni alloys was both the impactor material and the target material. [ABSTRACT FROM AUTHOR]

• A more refined 3-D structure of study area was determined. • 3-D morphology of a high-density anomaly bodies inside Mare Crisium was obtained for the first time. • A clear crust-mantle interface uplift rebound is found in center of Mare Crisium. Mare Crisium is a typical Mascon on the Moon, and a detailed 3-D structure of the lunar crust and upper mantle is essential to explore the causes of the lunar Mascon. However, research in the Mare Crisium region has focused more on surface rather than internal structure in the past few decades. With the development of space exploration technology, lunar gravity data have been applied several times to determine the internal structure of the Moon. Nevertheless, the gravity method has limitations in terms of vertical resolution. To address this issue, this paper adopts the wavelet multi-scale analysis method to decompose the gravity anomaly data in the Mare Crisium region. The power spectrum method is then used to estimate the mean source depth of the decomposed gravity anomaly signal. On the one hand, the gravity anomaly signal and its corresponding mean source depth at different scales can be used to stratify the structure of the lunar crust and upper mantle in the Mare Crisium region, and then obtain the density structure of each layer. On the other hand, the gravity anomaly signals from the crust-mantle undulations are extracted and combined with prior information to invert the depth of the crust-mantle interface in the Mare Crisium region. As a result, the 3-D structure of the lunar crust and upper mantle in the Mare Crisium region was obtained. The study indicates that there are two high-density bodies with a large range in the interior of Mare Crisium. The first high-density body is located in the western part of the Mare Crisium, and the centre of its bottom is about 54°E longitude and 17°N latitude. The second high-density body is located in the northeast of the Mare Crisium, and the centre of its base is about 63°E longitude and 25°N latitude. Additionally, the study found that the crust-mantle interface of the Mare Crisium is obviously uplifted, and the uplifting rebound phenomenon exists in the centre of the basin. Considering the depth and size of the high-density body, Mare Crisium probably experienced two high-angle, high-speed impacts at least. [ABSTRACT FROM AUTHOR]

Moon is an auspicious environment for the study of Galactic cosmic rays (GCR) and Solar Particle Events (SEP) due to the absence of magnetic field and atmosphere. The same characteristics raise the radiation risk for human presence in orbit around it or at the lunar surface. The secondary (albedo) radiation resulting from the interaction of the primary radiation with the lunar soil adds an extra risk factor, because neutrons are produced, but also it can be exploited to study the soil composition. In this paper, the design of a comprehensive radiation monitor package tailored to the lunar environment is presented. The detector, named LURAD, will perform spectroscopic measurements of protons, electrons, heavy ions, as well as gamma-rays, and neutrons. A microdosimetry monitor subsystem is foreseen which can provide measurements of LET(Si) spectra in a wide dynamic range of LET(Si) and flux for SPE and GCR, detection of neutrons and biological dose for radiation protection of astronauts. The LURAD design leverages on the following key enabling technologies: (a) Fully depleted Si monolithic active pixel sensors; (b) Scintillators read by silicon photomultipliers (SiPM); (c) Silicon on Insulator (SOI) microdosimetry sensors; These technologies promise miniaturization and mass reduction with state-of-the-art performance. The instrument's design is presented, and the Monte Carlo study of the feasibility of particle identification and kinetic energy determination is discussed. [ABSTRACT FROM AUTHOR]

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. Plain Language Summary: Ring‐moat dome structures (RMDSs) are common features across a large expanse of the lunar mare surface, but their nature is poorly understood. A key recent observation is that RMDSs have a close relationship with mare dome‐style volcanism, which represents a typical eruption style on the Moon, providing a useful window into the composition and geophysical evolution of the lunar interior. In this study, a total of 80 mare domes in Mare Tranquillitatis were found to be superimposed by varying numbers of RMDSs on their tops and flanks. RMDSs were also found in the maria surrounding these domes. The nature, correlation, and morphologic properties of the RMDSs and their host mare domes were measured. Based on new observations, a basalt flow emplacement scenario for the formation of both mare domes and associated volcanic features (e.g., RMDSs) related to dike‐closing in the late stages of eruptions is reviewed and updated to account for these observed associations. Key Points: The presence of RMDSs on some mare domes is attributed to be due to relatively higher effusion rates forming longer thinner flowsDike‐fed volcanic eruptions from the shallow subcrustal magma reservoirs are likely to favor the production of domes around the ventThe Tranquillitatis dome‐RMDS association can be explained by adapting the RMDS theoretical model to the shallow subcrustal magma reservoir model [ABSTRACT FROM AUTHOR]

Remote sensing observations represent the primary means in the production of geologic maps of planetary surfaces. However, they do not provide the same level of detail as Earth's geologic maps, which rely also on field observations and laboratory analyses. Color‐derived basemaps can help to bridge this gap by highlighting peculiar surface and compositional properties. Here, we analyzed the spectral properties of the lunar Tsiolkovskiy crater through the definition of spectral units summarizing the information enclosed by a set of selected spectral parameters. We then performed a compositional analysis of the newly derived spectral units that helped us in discriminating the presence and relative abundance of the main mineralogical phases on the Moon. As a final step, we produced a geo‐stratigraphic map of the Tsiolkovskiy crater integrating in a single mapping product both morphologic, stratigraphic and compositional information. The basaltic infilling of the crater is distinguished by three spectral units associated with distinct effusive events presenting a different composition. On the central peak, plagioclase and olivine suggest the presence of Mg‐suite rocks from the lower crust. The continuous ejecta deposits are mostly characterized by impact melts and shocked materials rich in glass or agglutinates related to more mature terrains from which occasionally appear fresher anorthositic and gabbroic outcrops exposed by the inward sliding of the crater walls. Overall, the geo‐stratigraphic map allows inferring compositional variations associated with the different morpho‐stratigraphic units, which clarify and elaborate on the compositional heterogeneities within the lunar crust and the Tsiolkovskiy crater, and its geologic evolutionary history. Plain Language Summary: The main data used to produce geologic maps of planetary surfaces come from orbiting missions. However, geologic maps of Earth provide much more information, relying also on observations made on the field and analyses made in the laboratory. Color images derived from the combination and processing of spectral information can help to make planetary maps more comprehensive, similarly to the Earth's ones, by drawing attention to surface and compositional aspects. In this work, we performed a spectral and compositional study of the Tsiolkovskiy crater on the Moon which enabled us to distinguish the presence and relative quantity of the most common minerals constituting the lunar rocks. We also produced a geo‐stratigraphic map coupling the information about the surface textures and shapes, relative time of deposition, and composition. On the basaltic floor, we discriminated the presence of three different spectral characteristics correlated with a sequence of flooding events showing distinct properties and a central peak exhibiting rocks emerged from the lowest strata of the lunar crust. The continuous ejecta blanket, instead, is characterized by mature materials interspersed by fresher exposures of subsurface materials. To conclude, the new mapping product allows an in‐depth interpretation of the geologic evolution of the Tsiolkovskiy crater. Key Points: Production of a 10‐unit Spectral Units map conveying the spectral and compositional properties within the Tsiolkovskiy craterIntegration of geologic and spectral units to produce a more comprehensive mapping product, namely a geo‐stratigraphic mapElaboration on the geological and compositional evolution of our study area [ABSTRACT FROM AUTHOR]

Lunar polar region has become the focus of future explorations due to the possible ice reservoir in the permanently shadowed craters. However, the space environment near the polar crater is quite complicated, and a plasma mini‐wake can be caused by the topographic obstruction. So far, three‐dimensional (3D) numerical simulations of the mini‐wake around a crater far larger than the Debye length are still limited. Here we present a 3D electrostatic hybrid particle‐in‐cell model to study the plasma mini‐wake of a polar crater on scale of about 1 km. It is found that the mini‐wake can begin upstream from the crater with a cone angle of about 8.8°. There is a plasma void with extra electrons near the leeward crater wall, where the electric potential can be as low as −60 V. A part of solar wind ions can be diverted into the crater, and the ratio of the diverted flux is about 4% on the crater bottom and about 18% on the windward crater wall, which provide an important source for the surface sputtering. Further studies show that the mini‐wake can change with the solar wind parameters and the crater shapes. Our results are helpful to assess the space environment and the water loss rate of a polar crater, and have general implications in studying the plasma mini‐wake caused by a crater on the other airless bodies. Key Points: We present a 3D electrostatic hybrid model to study the plasma mini‐wake caused by a polar crater far larger than the Debye lengthThe plasma mini‐wake is dependent on both the solar wind parameters and the crater shapesA large number of solar wind ions can be diverted into the crater and result in a water loss from the polar crater [ABSTRACT FROM AUTHOR]

The formation and evolution of the South Pole‐Aitken (SPA) basin is critical to relating large impact basin formation and modification to lunar geophysical evolution. Most prior models of the SPA impact were conducted in 2D, making it difficult to compare model output to the 3D crustal structure and ejecta distribution. In order to better constrain the parameters of the SPA impactor and the expected post impact distribution of crust and ejecta, we conducted numerical simulations of the SPA impact in 3D. We tested a wide range of impact parameters and constrained model results with recent geophysical data. We found the crustal structure of the SPA basin is best fit by an oblique impact (30–45°) of a 350–400 km diameter projectile impacting at 12–16 km/s. The impact excavated material from as deep as 80–120 km, and ejecta was deposited in a butterfly pattern with a forbidden region uprange of the impact. Plain Language Summary: The South Pole‐Aitken (SPA) basin is the largest impact‐generated structure on the Moon. The large size of the basin (approximately 1,500–2,000 km in diameter) implies the impact that generated the basin globally influenced the early evolution of the Moon. In order to constrain the type of impact that formed the basin, we ran computer simulations of large projectiles (300–400 km in diameter) impacting the early lunar surface. We found the structure of the crust surrounding the basin best matches an impact of a 350–400 km diameter projectile (similar in scale to Saturn's moon Mimas) impacting the Moon with a velocity of 12–16 km per second. Our computer models show that the collision that generated the basin would have formed a non‐symmetrical distribution of impact ejecta, and excavated material from the lower crust and upper mantle. Our results constrain the type of impact that formed the SPA basin, and suggest that ejecta from the impact is prevalent at sites of current and future lunar exploration. Key Points: 3D simulations constrain the South Pole‐Aitken (SPA) impactor to 350–400 km diameter impacting at 12–16 km/s and 30–45°The SPA impact excavated lower crust and upper mantle lunar materials, and emplaced ejecta in a butterfly type ejecta patternThe thick crustal annulus present in model results requires further modeling of basin collapse and post‐impact relaxation [ABSTRACT FROM AUTHOR]

Impact craters that form on every planetary body provide a record of planetary surface evolution. On heavily cratered surfaces, new craters that form often overlap antecedent craters, but it is unknown how the presence of antecedent craters alters impact crater formation. We use overlapping complex crater pairs on the lunar surface to constrain this process and find that crater rims are systematically lower where they intersect antecedent crater basins. The rim morphology of the new crater depends on the depth of the antecedent crater and the degree of overlap between the craters. Our observations suggest that new craters do not always obliterate underlying topography and that transient rim collapse is altered by antecedent topography. This study represents the first formalization of the influence of antecedent topography on rim morphology and provides process insight into a common impact scenario relevant to the geology of potential Artemis landing sites. Plain Language Summary: Craters form on the surface of many planetary bodies and help us to understand many qualities of the surface including, critically, the age of the surface. On older surfaces with many craters, new craters that form often overlap and partially destroy older craters, though we don't know if or how the presence of the older crater changes the processes that create the new crater. Looking at large Lunar craters, we can determine that the presence of an older crater causes the rim of the new crater to be asymmetric: lower where it forms within the older crater basin. The difference in height between the new crater rim inside and outside the old crater depends on both the depth of the older crater, and where the new crater forms relative to the older crater. From this we can interpret that the presence of the older crater alters the way the new crater forms, leading to an uneven collapse of early rim materials. Key Points: Overlapping complex crater rims are lower inside the antecedent basins compared to outsideDeeper antecedent basins and more significant crater overlap tend to create larger differences in rim heightChanges in the impact crater formation process, mainly during transient rim collapse, influence the shape of overlapping crater rims [ABSTRACT FROM AUTHOR]

Water ice and other volatiles that accumulated in the Moon's polar regions are among the top priority targets for lunar exploration, due to their significances in both lunar geology and extraterrestrial resource utilization. Locating suitable landing sites and determining the provenance of sampled/measured surface materials are critical for future landed missions. Here, we map over 800 sites of plains terrains in the Moon's south polar region, with a total surface area of ~46,000 km2. Orbital measurements and analog studies show that most of these plains have apparently higher albedo and lower iron content than volcanic mare plains, suggesting an origin of ejecta-induced debris flows from distant impact craters, especially from the Schrödinger basin. Our findings suggest that the entire lunar south polar region probably have experienced contributions from distant basin materials. We recommend these plains as priority landing sites for future exploration of lunar polar volatiles and early bombardment history. The authors map extensive plains terrains in the Moon's south polar region, which originate from impact basin ejecta materials. These plains serve as attractive landing sites for future exploration of lunar polar volatiles and early bombardment history. [ABSTRACT FROM AUTHOR]

Following the processing of the Chang'e-4 satellite images, Chang'e-4 landing camera images, and Yutu-2 panoramic camera images, data were obtained in a variety of resolutions, including digital elevation model (DEM) and digital orthophoto map (DOM). By determining the morphological parameters, including the depths and diameters of impact craters in the study area, as well as their degradation classes based on surface texture features, we conducted a comprehensive analysis of the morphological parameters and population degradation patterns of impact craters from multiple platforms. The data from three platforms were employed to identify 12,089 impact craters with diameters ranging from 0.1 m to 800.0 m, which were then classified into five degradation classes based on their morphology in the images. This study indicates that as the size of impact craters increases, the population within them experiences a greater degree of degradation. However, the severe degradation of impact craters with diameters of less than 1 m or even 2 m is influenced by the rapid rate of degradation of the crater and the low solidity of the crater lips. The results of the equilibrium state of impact craters indicate that for sub-metre-sized impact craters (with diameters below 2.0 m), it is challenging to reach equilibrium. Furthermore, the smaller the impact crater, the more difficult it is to achieve equilibrium, which is probably the result of simpler generation conditions and the faster degradation of small impact craters. [ABSTRACT FROM AUTHOR]

Impact crater detection is one of the most important and critical studies of the geological history of planetary surfaces. Recent literature on crater identification demonstrates the powerful potential of deep-learning algorithms. However, these methods potentially assumed that the detection is conducted in devices with sufficient computing resources, and used networks with massive learnable parameters to obtain superb performance. In this paper, we proposed a lightweight tensorial convolutional neural network (CNN) for lunar impact crater detection. Specifically, we develop a tensorial you only look once (TYOLO) network by representing the convolutional kernels in tensor train (TT) decomposition. Thus, the parameter redundancy of TYOLO can be greatly reduced. To the best of our knowledge, this is the first work that considers the lightweight CNN model for impact crater detection. We demonstrate the lunar impact crater detection results over the ChangE-2 lunar digital orthophotos model (DOM) and digital evaluated model (DEM). Experimental results show that the proposed TYOLO network can obtain 1.44 × speed up and 39 × compression with 2.4 % improvement in crater detection. Overall, the proposed network demonstrates great potential in spacecraft with emerging computing resource constraints. [ABSTRACT FROM AUTHOR]

There are likely many undiscovered impact structures on Earth, but several challenges prevent their detection, including possible concealment beneath large ice sheets. In recent years, geophysical, geochemical, and microphysical evidence has mounted for a ca. 58 Ma impact structure under the Hiawatha Glacier, northwest Greenland. Here, we report evidence for a second, much older hypervelocity impact event in this region, recorded in an impact melt rock sample collected from a glaciofluvial deposit in Inglefield Land. Secondary ion mass spectrometry U-Pb analyses of shock metamorphosed zircon grains yielded a previously unrecorded, Proterozoic best estimate impact age of 1039 ± 16 Ma (mean square of weighted deviates = 2.9). Based on Archean-Proterozoic target rock U-Pb ages obtained from unshocked zircon grains and the location of the melt rock sample along the ice margin, we suggest this sample was derived from a hypervelocity impact structure farther inland, concealed by the Greenland Ice Sheet. This study demonstrates the ability to uncover new impact events in some of the most inaccessible areas on Earth and the possibility of sampling multiple impact structures from one location when examining ex situ material. Our results have implications for current and future Martian and lunar returned samples that demonstrably bear complex impact histories. [ABSTRACT FROM AUTHOR]

Small topographic features below the resolution of existing orbital data sets may create "micro ultra‐cold traps" within the larger permanently shadowed regions that are present at the lunar poles. These ultra‐cold traps are protected from the major primary and secondary illumination sources, and thus would create surfaces that are much colder than lower‐resolution temperature maps would indicate. We examine this effect by creating a high resolution (1 m pix−1) terrain map based on upscaled data from the Lunar Orbiter Laser Altimeter. This map is illuminated by scattered sunlight and infrared emissions from sunlit terrain, which are then run through a thermal model to determine temperatures. We find that while most of the terrain experiences maximum temperatures around 50 K, there are a number of 1–30 m‐scale ultra‐cold traps with maximum temperatures as low as 20–30 K. By comparing our modeled ultra‐cold trapping area to volatile abundances measured by Lunar Crater Observation and Sensing Satellite (LCROSS), we reveal a diverse environment where the surficial abundances necessary to explain the LCROSS results are strongly dependent on precisely where the impact occurred. Plain Language Summary: Near the Moon's poles, there exist large regions of permanent shadow that are much colder than the surrounding terrain. Their consistently low temperatures allow molecules like water to accumulate within them, potentially creating deposits that play a key role in long‐term crewed exploration of the Moon. Within these permanently shadowed regions, there are likely smaller areas that are shielded from secondary illumination sources like scattered sunlight, making these areas even colder than the permanently shadowed terrain around them and allowing them to trap additional molecules like carbon dioxide, methane, and ammonia. We have modeled the temperatures of the lunar surface at the Lunar Crater Observation and Sensing Satellite (LCROSS) impact site at a resolution of 1 m px−1 to examine to what extent these small‐scale terrain features could explain the molecular abundances measured by LCROSS. By comparing our modeled temperatures to the LCROSS results, we find that the surface composition responsible for the LCROSS measurements depends on whether LCROSS impacted one or more of these small, extremely cold regions. Key Points: We model surface temperatures at the Lunar Crater Observation and Sensing Satellite (LCROSS) impact site at a resolution of 1 m px−1Small craters create ultra‐cold (<25 K) regions that enhance the surface's ability to cold‐trap non‐water volatilesComparisons with LCROSS volatile abundances reveal a diverse environment of potential surficial volatile compositions [ABSTRACT FROM AUTHOR]

The icy Galilean satellites display impact crater morphologies that are rare in the Solar System. They deviate from the archetypal sequence of crater morphologies as a function of size found on rocky bodies and other icy satellites: they exhibit central pits in place of peaks, followed by central dome craters, anomalous dome craters, penepalimpsests, palimpsests, and multi‐ring structures. Understanding the origin of these features will provide insight into the geophysical factors that operate within the icy Galilean satellites. Pit craters above a size threshold feature domes. This trend, and the similarity in morphology between the two classes, suggest a genetic link between pit and dome craters. We propose that dome craters evolve from pit craters through topographic relaxation, facilitated by remnant heat from the impact. Our finite element simulations show that, for the specific crater sizes where we see domes on Ganymede and Callisto, domes form from pit craters within 10 Myr. Topographic relaxation eliminates the stresses induced by crater topography and restores a flat surface: ice flows downwards from the rim and upwards from the crater depression driven by gravity. When the starting topography is a pit crater, the heat left over from the impact is concentrated below the pit. Since warm ice flows more rapidly, the upward flow is enhanced beneath the pit, leading to the emergence of a dome. Given the timescales and the dependence on heat flux, this model could be used to constrain the thermal history and evolution of these moons. Plain Language Summary: Ganymede and Callisto are large icy moons orbiting Jupiter, believed to be ocean worlds. These moons' surfaces display impact craters with shapes not seen elsewhere in the Solar System. This may be due to factors such as their high gravity, temperature, presence of subsurface oceans, and/or impactor characteristics. By exploring these atypical craters, we aim to shed light on the inner workings and evolution of these moons and, by extension, contribute to a clearer picture of the evolution of the outer Solar System. This study focuses on unveiling the origins of dome craters on Ganymede and Callisto, which have rounded bright domes in the center and are virtually unique to these moons. We believe these domes are connected to a relatively more common crater, the pit crater. Our simulations show that a pit crater can evolve into a dome crater within 10 million years as the ice flows slowly under its own weight. This flow is channeled back into the center creating a dome, aided by warm temperatures left over from the impact that soften the ice below the pit. This occurs only for the specific sizes where we see dome craters on these moons. Key Points: Dome craters form via topographic relaxation of pit craters for sizes larger than ∼60 kmRemnant heat from the impact enhances relaxation at the center of the pit crater, causing domes to emergeEven young dome craters can form from the relaxation of pit craters due to the relatively short timescales required (∼10 million years) [ABSTRACT FROM AUTHOR]

This study presents a comprehensive assessment of the geomorphology, crater distributions, and tectonic structures within Enceladus' cratered terrains. We analyzed the distributions of impact craters and tectonic structures in seven regions of interest to inform an interpretation of the geological history of this terrain in the context of Enceladus' global evolution. We found that the tectonic structures, including both ancient, subdued troughs and young, narrow fractures, point to a cratered terrain that not only experienced early tectonic modification but also shows evidence of recent geological activity. Ancient troughs present in the equatorial cratered terrains are similar in scale and orientation to troughs present in the Leading and Trailing Hemisphere Terrains, an observation that supports possible non‐synchronous rotation of the ice shell. A dearth of impact craters in the equatorial regions as identified previously does not hold for craters <3 km in diameter in the anti‐Saturnian hemisphere. The anomalous presence of excess small craters in this region could be due to secondary or sesquinary impacts from a catastrophic event occurring at Enceladus or a neighboring moon. Finally, narrow fractures are pervasive across the cratered terrains and are most commonly oriented parallel or sub‐parallel to the most proximal cratered terrain boundary. This directionality of pervasive recent fracturing could be related to the vertical movement of an isostatically uncompensated ice shell. Enceladus' cratered terrains provide insight into the long‐term evolution of the satellite, an important component to assessing its role in Solar System evolution and its potential for habitability. Plain Language Summary: We present a comprehensive characterization of the oldest terrain on Enceladus, the cratered terrains. We evaluated structural features and impact craters on the surface, including their morphology and spatial distributions. This analysis informs how we interpret the formation and change of these surface features in the context of how Enceladus as a whole has changed over time. We found that there are two main types of tectonic structures in the cratered terrains, including one set of relatively old troughs and at least one set of narrow fractures that is very young. This finding indicates that not only have the cratered terrains experienced early tectonic activity, but were also active recently. The ancient set of troughs are similar to those present in younger terrains on Enceladus, suggesting that the ice shell has rotated relative to its tidally locked position about Saturn. The comparatively young, narrow fractures in the cratered terrains are widespread and could have formed due to a vertically shifting ice shell. Enceladus' cratered terrains provide insight into what long‐term changes have taken place on the surface, an important component to understanding how Enceladus fits into Solar System formation and its past or present potential to host life. Key Points: Systematic review of Enceladus' cratered terrains results in a stratigraphic framework for geologic mapping and age determinationTroughs in the equatorial cratered terrains are similar to tectonized equatorial regions, suggesting non‐synchronous ice shell rotationAncient, subdued troughs and young, narrow fractures point to a cratered terrain that experienced both early and recent tectonic activity [ABSTRACT FROM AUTHOR]

Seismic observations of impacts on Mars indicate a higher impact flux than previously measured. Using six confirmed seismic impact detections near the NASA InSight lander and two distant large impacts, we calculate appropriate scalings to compare these rates with lunar-based chronology models. We also update the impact rate from orbital observations using the most recent catalog of new craters on Mars. The snapshot of the current impact rate at Mars recorded seismically is higher than that found using orbital detections alone. The measured rates differ between a factor of 2 and 10, depending on the diameter, although the sample size of seismically detected impacts is small. The close timing of the two largest new impacts found on Mars in the past few decades indicates either a heightened impact rate or a low-probability temporal coincidence, perhaps representing recent fragmentation of a parent body. We conclude that seismic methods of detecting current impacts offer a more complete dataset than orbital imaging. [ABSTRACT FROM AUTHOR]

We quantify the effect of dust accumulation at Jezero crater by means of a Dust Correction Factor (DCF) for the solar radiation measured by the photodiodes of the Radiation and Dust Sensor of the Mars 2020 mission. After one Mars Year, dust on the photodiode surface attenuated 25%–30% of the incoming solar radiation. The DCF did not decrease monotonically; we use a model to reproduce its evolution and to derive dust deposition and lifting rates, showing that dust removal is 9 times larger at Jezero crater than at InSight's location in western Elysium Planitia. The model fit obtained using observed opacities is further improved when fed with dust sedimentation rates simulated by a GCM that considers a particle size distrtibution. Projections show seasonal net dust removal, being encouraging for the long‐term survival of solar‐powered missions to Jezero or similarly active dust lifting regions. Plain Language Summary: Dust is ubiquitous in the Martian atmosphere, accumulating on both natural and artificial surfaces. Dust particularly affects the performance and lifetime of missions: the termination of InSight and MER‐B operations are recent examples. Dust accumulation shows a seasonal behavior, and attenuated 25%–30% of the incoming solar radiation on Perseverance after the first Mars Year of the mission. Dust removal is almost 10 times larger than at InSight's location: projections indicate that surfaces at Jezero will be periodically partially cleaned. The estimations of the effect of the accumulated dust as a function of time are encouraging for solar‐powered missions to regions with similar amounts of dust lifting, which might be determined from orbital data on where dust storms originate, dust devils or their tracks are found, or seasonal albedo changes are noted. In addition, the quantification of the effect of accumulated enables future studies requiring more accurate knowledge of incoming solar radiation at the surface. Key Points: We present the evolution of dust accumulation at Jezero crater for more than one Mars YearWe derive dust deposition and removal rates: removal is 9 times more efficient than at the InSight location in western Elysium PlanitiaProjections show that surfaces at Jezero will experience seasonal net dust removal, encouraging solar‐powered missions [ABSTRACT FROM AUTHOR]

Impact craters, as the most distinct lunar structural unit and geological structure, are marked on the Moon's surface. For over a decade, researchers have focused on identifying and exploring large- to medium-sized impact craters on the surface of the Moon (craters with a diameter greater than 1 km). Small impact craters have obvious statistical significance owing to their magnitude in numbers. The identification and analysis of small craters provide indispensable clues for the study of lunar geological evolution. However, such craters only remain in specific images and regions. At present, there is no comprehensive record of small impact craters in the existing lunar impact crater databases. The small impact craters on the surface of the Moon are enormous and vary in size by orders of magnitude, exhibiting small target characteristics in space. The present study focuses on the identification and spatial analysis of small impact craters on the surface of the Moon. A feature amplification strategy-based identification model was established for small impact crater detection, achieving accurate recognition of the small impact craters on the surface of the Moon (with a recall rate of 86.97% and a false-positive rate as low as 0.54% ± 0.16%). In total, 228,897, 142,872, and 42,008 new small lunar impact craters (with diameters as low as 4.5 m) were identified in the ten lunar landing areas of returned samples from the Apollo, Luna, and Chang'e-5 missions. In addition, the spatial distribution characteristics of small impact craters during different geological periods in the landing area are provided. Data on the newly identified small impact craters will provide an important basis for revealing the lunar impact fluxes and young lunar surface dating in lunar geological evolution research. [ABSTRACT FROM AUTHOR]