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Cold traps are locations on the Moon that are shielded from sunlight where volatiles such as water could accumulate and persist against sublimation for geologic timescales. We model how long it takes accumulating craters to produce and then obliterate sub‐kilometer scale cold traps. Sub‐meter cold traps are extremely ephemeral, evolving in and out of existence over less than a few thousand years; however, larger 100 m to 1 km‐scale cold traps may persevere for geologic timescales and preserve a record of the volatile history of the Moon. Plain Language Summary Volatiles like water may exist in the shadows at the bottom of craters near the poles of the Moon; however, the Moon is subjected to intense bombardment by high‐velocity meteorites, and the subsequent bombardment by the rocks meteorite impacts kick up. Crater‐forming bombardment controls both the production and destruction of craters where volatiles may be safe. Using knowledge of the intensity of bombardment, we model how long volatile‐harboring cold traps last on the Moon and find that small cold traps (<10 m) are extremely ephemeral, while large cold traps (>100 m) could last for geologic time. Key Points Lunar micro cold traps are extremely ephemeral (<1 m scale last only thousands of years) Volatiles discovered within micro cold traps will have been transported there recently Large cold traps are exponentially more durable than small cold traps and may harbor ancient volatiles

We present the first full‐wavelength numerical simulations of the electric field generated by cosmic ray impacts into the Moon. Billions of cosmic rays fall onto the Moon every year. Ultra‐high energy cosmic ray impacts produce secondary particle cascades within the regolith and subsequent coherent, wide‐bandwidth, linearly‐polarized radio pulses by the Askaryan Effect. Observations of the cosmic ray particle shower radio emissions can reveal subsurface structure on the Moon and enable the broad and deep prospecting necessary to confirm or refute the existence of polar ice deposits. Our simulations show that the radio emissions and reflections could reveal ice layers as thin as 10 cm and buried under regolith as deep as 9 m. The Askaryan Effect presents a novel and untapped opportunity for characterizing buried lunar ice at unprecedented depths and spatial scales. Plain Language Summary Particles traveling at extreme speeds, or cosmic rays, impact the Moon so fast that they cause particle cascades that exceed the phase velocity of light (the speed at which a specific point on a light wave travels) in the lunar soil. In a process analogous to a sonic boom, they generate cones of electromagnetic shock waves, the radio emission of which is called the Askaryan Effect. The Askaryan phenomenon produces uniquely identifiable radio waves and retains information about subsurface layers the way radar or sonar sounding would. Unlike radar, which requires high‐power antennas to emit radio signals, sensors listening for the Askaryan Effect hear echoes from naturally occurring cosmic ray impacts, drastically lowering the cost and complexity of these detectors. Here, we show for the first time that the Askayan Effect would produce observable signals from buried ice layers at the lunar poles, providing a novel and untapped method of probing for buried water ice deposits on the Moon. Key Points Ultra‐high energy cosmic ray impacts into the Moon generate radio pulses by the Askaryan Effect Radio emissions generated by the Askaryan Effect can reveal subsurface structure on the Moon Cosmic ray particle shower‐generated radio emissions could enable broad and deep prospecting for subsurface ice

We present model mineralogy of impact crater central peaks combined with crustal thickness and crater central peak depth of origin models to report multiple perspectives of lunar crustal composition with depth. Here we report the analyses of 55 impact crater central peaks and how their compositions directly relate to the lunar highlands sample suite. A radiative transfer model is used to analyze Clementine visible plus near‐infrared spectra to place compositional constraints on these central peak materials. Central peaks analyzed are dominantly magnesian‐ and plagioclase‐poor; strong compositional similarities to lunar Mg‐suite materials are evident. Relative to crustal thickness estimates, central peak mineralogy becomes more plagioclase‐rich as the crust thickens. Relative to the crust‐mantle boundary, the origin of peaks with dominantly mafic mineralogy are confined to the lower crust and primarily within the South‐Pole Aitken and Procellarum KREEP Terranes (PKT); additionally, central peaks with anorthositic mineralogy (>60 vol % plagioclase) are transported to the surface from all depths in the crustal column and confined to the Feldspathic Highlands Terrane (FHT). The discovery of mafic and magnesian materials, consistent with Mg‐suite rocks of the sample collection, in all lunar terranes suggests that the process and sources that give rise to these types of rocks is not unique to the PKT and not necessarily dependent on incompatible elements for formation. The identification of ferroan and magnesian anorthositic material near the crust‐mantle boundary of the FHT is also inconsistent with an increasing mafic/feldspar ratio and Mg' with depth in the crust.

Planetary analog simulations are a powerful exercise for understanding the utility of deployable instruments, their operational protocols, and the visualization of data products during ExtraVehicular Activities (EVAs). This paper presents results of a field campaign by the NASA Solar System Exploration Research Virtual Institute (SSERVI) Remote, In Situ and Synchrotron Studies for Science and Exploration‐2 (RISE2) team to Kilbourne Hole, New Mexico in March/April 2023 to test the utility of a portable thermal infrared (TIR) hyperspectral imager (HSI) during four EVA simulations. The HSI provides emitted radiance spectra from 7 to 14 μm to map spectral variations likely caused by composition and physical properties, which allows HSI data products to aid in sample selection and site documentation. Four pairs of analog astronauts performed a mock EVA at three stations with field deployable instruments including an HSI. The HSI was found to be a useful tool for performing reconnaissance observations, field site documentation, and sample selection for visibly indistinct materials. From these analog simulations we prioritize two recommendations for use of HSI's in crewed missions. First, HSI‐derived data products should be tailored for the specific science objectives and/or sampling objectives of the mission to expedite interpretation and decision‐making. Second, the HSI instrument would ideally have a wide field‐of‐view/panoramic capability to reduce crew time selecting sites to image. Additionally, pre‐EVA reconnaissance from a remotely operated rover could be conducted with an HSI to collect data prior to disturbance and again post human activity. Plain Language Summary Testing instruments in scenarios similar to how they would be used by astronauts on the Moon is important for developing useful data products and operational protocols. One such instrument that was tested is a portable thermal infrared hyperspectral imager (HSI) that provides information regarding the diversity of targets within an image. In a field test, we simulated how images from the HSI would be used to identify samples to collect and bring back to a laboratory for further detailed studies. Our field test revealed that the HSI is a useful tool for identifying unique and site representative samples, for planning which samples to collect, and for documentation of spectral (i.e., compositional information) characteristics of the site. Some recommendations that came from the field test include (a) tailoring the data products for the specific science to be addressed and samples collected, and (b) the HSI instrument should have a wide field‐of‐view/panoramic capability to reduce crew mental load. Additionally, the utilization of an HSI prior to human activity via remote operations could potentially enhance the science return of an HSI. Key Points Hyperspectral imagers aid in reconnaissance and detection of visibly indistinct materials (i.e., volatiles) Hyperspectral imaging instruments and their data products should be adaptable to various scientific and operational needs Recommendations include data products tailored to science objectives and expanded FOV capabilities to reduce the mental load on crew

Analysis of Mariner 10 and MESSENGER data sets reveal the importance of opaque components on Mercury's surface. A global darkening agent, suggested to be ilmenite or other Fe‐, Ti‐bearing opaque mineral, has been invoked to explain the lower albedo of Mercury relative to the lunar highlands. Separately, a low‐reflectance material (LRM) has been recognized as one of three dominant color terrains. We present laboratory reflectance spectra of ilmenite size separates and other candidate Fe‐, Ti‐bearing oxide minerals. These oxides cannot sufficiently darken Mercury without violating neutron spectrometer constraints on surface iron content. The spectra of all samples exhibit negative spectral slopes shortward of 500 nm, consistent with the LRM. We review models of crystallization of an FeO‐poor Mercurian magma ocean and show that lack of a plagioclase flotation crust could lead to a thin quench crust with near surface layers of incompatible‐ and Ti‐rich late stage cumulates, consistent with Mercury's albedo and LRM.

Widespread hydration was detected on the lunar surface through observations of a characteristic absorption feature at 3 µm by three independent spacecraft 1 – 3 . Whether the hydration is molecular water (H 2 O) or other hydroxyl (OH) compounds is unknown and there are no established methods to distinguish the two using the 3 µm band 4 . However, a fundamental vibration of molecular water produces a spectral signature at 6 µm that is not shared by other hydroxyl compounds 5 . Here, we present observations of the Moon at 6 µm using the NASA/DLR Stratospheric Observatory for Infrared Astronomy (SOFIA). Observations reveal a 6 µm emission feature at high lunar latitudes due to the presence of molecular water on the lunar surface. On the basis of the strength of the 6 µm band, we estimate abundances of about 100 to 400 µg g −1 H 2 O. We find that the distribution of water over the small latitude range is a result of local geology and is probably not a global phenomenon. Lastly, we suggest that a majority of the water we detect must be stored within glasses or in voids between grains sheltered from the harsh lunar environment, allowing the water to remain on the lunar surface. The Stratospheric Observatory for Infrared Astronomy (SOFIA) looked at the Moon in the 6 µm wavelength region and found a signature of molecular water, distinguishing it from other forms of hydration. The authors estimate water abundances between 100 and 400 µg g − 1 at high latitudes, trapped within impact glasses or possibly in between grains.

The aim of the Lunar Legacy Project is to map the distribution of water on the Moon’s surface through the detection and characterization of the 6 μ m spectral band indicative of molecular water. Spectra were taken with the Faint Object infraRed Camera for the SOFIA Telescope instrument on the Stratospheric Observatory for Infrared Astronomy (SOFIA) between 2018 and 2022. This paper describes the processing steps necessary to reduce the raw data downloaded from the SOFIA archive to create flux-calibrated spectra. The reduction mostly requires the SOFIA Redux package which can be downloaded from the SOFIA website, and some steps in the process require scripts written by our team in Python.

As a first step in preparing for the return of samples from the Moon by the Artemis Program, NASA initiated the Apollo Next Generation Sample Analysis Program (ANGSA). ANGSA was designed to function as a low-cost sample return mission and involved the curation and analysis of samples previously returned by the Apollo 17 mission that remained unopened or stored under unique conditions for 50 years. These samples include the lower portion of a double drive tube previously sealed on the lunar surface, the upper portion of that drive tube that had remained unopened, and a variety of Apollo 17 samples that had remained stored at −27 °C for approximately 50 years. ANGSA constitutes the first preliminary examination phase of a lunar “sample return mission” in over 50 years. It also mimics that same phase of an Artemis surface exploration mission, its design included placing samples within the context of local and regional geology through new orbital observations collected since Apollo and additional new “boots-on-the-ground” observations, data synthesis, and interpretations provided by Apollo 17 astronaut Harrison Schmitt. ANGSA used new curation techniques to prepare, document, and allocate these new lunar samples, developed new tools to open and extract gases from their containers, and applied new analytical instrumentation previously unavailable during the Apollo Program to reveal new information about these samples. Most of the 90 scientists, engineers, and curators involved in this mission were not alive during the Apollo Program, and it had been 30 years since the last Apollo core sample was processed in the Apollo curation facility at NASA JSC. There are many firsts associated with ANGSA that have direct relevance to Artemis. ANGSA is the first to open a core sample previously sealed on the surface of the Moon, the first to extract and analyze lunar gases collected in situ , the first to examine a core that penetrated a lunar landslide deposit, and the first to process pristine Apollo samples in a glovebox at −20 °C. All the ANGSA activities have helped to prepare the Artemis generation for what is to come. The timing of this program, the composition of the team, and the preservation of unopened Apollo samples facilitated this generational handoff from Apollo to Artemis that sets up Artemis and the lunar sample science community for additional successes.

The abundance and distribution of iron on the moon is derived from a near-global data set from Clementine. The determined iron content of the lunar highlands crust (∼3 percent iron by weight) supports the hypothesis that much of the lunar crust was derived from a magma ocean. The iron content of lower crustal material exposed by the South Pole-Aitken impact basin on the lunar farside is higher (∼7 to 8 percent by weight) and consistent with a basaltic composition. This composition supports earlier evidence that the lunar crust becomes more mafic with depth. The data also suggest that the bulk composition of the moon differs from that of the Earth's mantle. This difference excludes models for lunar origin that require the Earth and moon to have the same compositions, such as fission and coaccretion, and favors giant impact and capture.

Owing to its internal ocean, Jupiter’s moon Europa can potentially host extant life. However, because Europa’s orbit is within Jupiter’s magnetosphere, chemical biosignatures that are exposed to space may be destroyed by high-energy electron radiation. It has been suggested that biosignatures may be preserved below the radiation-penetration depth of the top few centimetres. Impact gardening, the process by which small impacts mechanically churn the uppermost surface of airless bodies, is known to disrupt near-surface stratigraphy; however, no comprehensive estimate of the effect of gardening has yet been determined for Europa. Here we use an impact gardening model to show that gardening is a global process on Europa, and has churned, on average, the top 30 cm over the last several tens of millions of years, thus, exposing all material within the top 30 cm to surface radiation. We suggest that morphologically immature craters and regions of mass wasting at mid-to-high latitudes could be weakly impacted by both gardening and radiation, and should be preferred locations for the search for life on Europa. Modelling shows that impact gardening on Europa has the potential to churn the shallow subsurface material down to 30 cm very efficiently and globally, thus destroying potential habitable niches just below the surface. Some areas where both gardening and radiation are relatively weak are, however, identified.