This article reports on the initial calibration and performance of the High-resolution Volatiles and Minerals Moon Mapper (), slated for launch on the National Aeronautics and Space Administration's Lunar Trailblazer mission. is an imaging spectrometer measuring from 600 to 3,600 nm with 10-nm spectral sampling and 50-90 m/pixel ground sampling. The mission goal is to understand the form, abundance, and distribution of water across the lunar surface and the lunar water cycle, accomplished by measuring the distinct absorptions of water ice, adsorbed O, and OH/hydroxl while controlling for thermal effects with . also has the ability to measure mineralogical composition. has been assembled, tested and calibrated in preparation for launch and integrated on the Lunar Trailblazer spacecraft. We review the design, calibration process, results, and implications for Lunar Trailblazer science goals. We find 's radiometric sensitivity is sufficient to confidently measure 1% differences in absorption band strengths under direct solar illumination in single pixel data. In addition, has the radiometric precision to discriminate different species of volatile absorptions at irradiances of 1 W , which will enable mapping and discriminating water ice or other volatiles within most of the Moon's Permanently Shadowed Regions using terrain-scattered illumination.

This study presents high-resolution (140 m/pixel) controlled mosaics of Moon Mineralogy Mapper (M3) data in the lunar polar regions (80 degrees-90 degrees N/S), with a focus on assessing mineralogy and water content across the Artemis exploration zone. M3 extensively sampled the lunar polar regions, providing a high spatial resolution, hyper-spectral imaging dataset that uniquely covers reflectance absorptions of major minerals and water on the lunar surface. We developed a methodology to preferentially use M3 image cubes acquired when the star tracker was operational to ensure accurate spatial registration of M3 pixels in our new mosaics. Integrated band depth (IBD) analyses were conducted to map distributions of hematite and other mineral species at the Artemis exploration zone. We also derived water contents at the Artemis sites from our new M3 mosaics. Our findings indicate that the Artemis exploration zone is largely dominated by mature regolith that is probably rich in plagioclase. Hematite is predominantly concentrated on east-facing slopes, likely due to enhanced oxidation from Earth wind oxygen interacting with the lunar regolith. Pyroxene-rich exposures are observed in three Artemis candidate landing regions and they are all associated with fresh impact craters. The water distribution is highly variable, with higher concentrations on pole-facing slopes and near permanently shadowed regions, likely controlled by low surface temperatures. High water contents are observed at hematite exposures, which reinforces that water may play a crucial role in hematite formation on the Moon. These results provide valuable insights for future lunar exploration, aiding in the selection of landing sites, planning of traverse routes, and informing in situ resource utilization (ISRU) for the Artemis missions.

Spectral variations due to the removal of surface adsorbed H2O at 3 and 6 mu m in reflectance spectra on lunar soils and relevant minerals (olivine, pyroxene, and plagioclase) have been assessed. This study characterizes variations in hydration features as a function of lunar relevant surface temperatures, to further understand current (i. e., M-3, HRI-IR, VIMS) and future (i.e., Lunar Trailblazer) observations of diurnal changes in surface hydration. Additionally, we explore the utility of using the 6 mu m H2O feature to discern the speciation of surface hydration at 3 mu m. We perform controlled temperature measurements (25-200 C-degrees) in a Linkam THMS600 Environmental Stage fixed to a Bruker LUMOS Microscope Fourier Transform IR (mu FTIR) spectrometer. We observe clear and systematic changes in the strength of the 3 mu m H2O/OH feature associated with the thermal removal of adsorbed H2O, in addition to changes in the overall shape and band position of the feature in both the terrestrial and lunar samples. The strength of the 3 mu m feature for the compositionally distinct and relatively brighter Apollo highland soil (62231) is stronger and more symmetric than the 3 mu m feature observed for the darker mare soil (10084). While several silicate related absorption features are identified near 6 mu m, neither a distinguishable hydration feature nor any changes in reflectance that could be attributed to the presence or a change in the amount of surface adsorbed H2O were observed at 6 mu m.

Over the last two decades, an international program of lunar exploration has continued to pick up speed, with over ten countries launching missions towards the Moon, successful robotic landings by several of them, and plans for humans to return to the surface and begin—for the first time—to learn how to live and work on another planetary body. Multiple commercial companies are designing and launching lunar landers, heralding unprecedented public access to the lunar surface. The Moon is a celestial body with deep cultural meaning to a great number of populations across planet Earth. Thus, it is important to engage the whole world as the next fundamental science and exploration steps are taken.The importance of worldwide engagement in the science and exploration of the Moon is well established. Numerous organizations, including the International Lunar Exploration Working Group (ILEWG), the Moon Village Association, and the International Space Exploration Coordination Group (ISECG), have been developing roadmaps for international partnerships in lunar exploration, engaging countries that have not historically been a part of space exploration efforts. The International Lunar Year of 2027 (ILY2027) seeks to build on the strong foundation that these organizations have lain by forging a sustained campaign of collaborations involving scientists, policy makers, the commercial sector, educators, and the public throughout the world, to establish together new guidelines and standards for exploration and for disseminating scientific data.ILY2027 follows the tradition set by the International Geophysical Year of 1957–58, which advanced science, drove political collaborations, and caught the attention of the global public. ILY2027 seeks participation from diverse communities to collect and analyze data to understand the lunar environment, navigate challenging political issues such as resource utilization, protect the myriad historical, cultural, and scientific aspects of the Moon, and establish standards for operation as different countries and commercial companies move towards extended operations on the lunar surface. At the Europlanet Science Congress, we will present initial high-level scientific and cultural goals for ILY2027, with the aim of broadening involvement and engaging nations and other interested parties across the world.

Although pyroxene has been detected remotely across the Solar System, limited information is available from infrared remote sensing about the Mg‐Fe composition of pyroxene, and distinguishing between augite (20 < CaSiO 3 < 45) and diopside‐hedenbergite (CaSiO 3 > 45) remains challenging. The characteristics of pyroxene in the intermediate infrared range (4–8 μm), meanwhile, have not been documented. Using reflectance spectra of 72 samples ranging across the pyroxene quadrilateral, we investigate the effect of variations in Mg# (Mg/[Mg + Fe] × 100) and Ca‐content on the positions of strong and well‐defined spectral bands at ∼5.1 and ∼5.3 μm in high‐Ca pyroxene and ∼5.2 in low‐Ca pyroxene. We find that the 5.1, 5.2, and 5.3 μm bands move to shorter wavelengths as Mg# increases, whereas Ca‐content does not significantly affect the positions of these bands, enabling the determination of pyroxene Mg# directly from band positions alone. We also find that the ∼5.1 μm band is significantly more distinctive in diopside‐hedenbergite and the ∼5.3 μm band significantly more so in augite. Therefore, the 5.1, 5.2, and 5.3 μm spectral bands enable discrimination among diopside‐hedenbergite, low‐Ca pyroxene, and augite. Additionally, the 5.1, 5.2, and 5.3 μm bands enable direct determination of Mg# of diopside‐hedenbergite, low‐Ca pyroxene, and augite within ±23, ±10, and ±29 mol% Mg‐Fe, respectively.

Research Article| December 01, 2023 The Evolution of the Lunar Crust Stephen M. Elardo; Stephen M. Elardo The Florida Planets Lab, Department of Geological Sciences, University of Florida, Gainesville, FL 32611, USAEarth and Planets Laboratory, Carnegie Institution for Science, Washington, DC 20015, USA selardo@ufl.edu Search for other works by this author on: GSW Google Scholar Carle M. Pieters; Carle M. Pieters Department of Earth, Environmental, and Planetary Sciences, Brown University, Providence, RI 02912, USA carle_pieters@brown.edu Search for other works by this author on: GSW Google Scholar Deepak Dhingra; Deepak Dhingra Department of Earth Sciences, Indian Institute of Technology Kanpur, Kalyanpur, Kanpur 208016, Uttar Pradesh, India Search for other works by this author on: GSW Google Scholar Kerri L. Donaldson Hanna; Kerri L. Donaldson Hanna Atmospheric, Oceanic and Planetary Physics, University of Oxford, Oxford, UKDepartment of Physics, University of Central Florida, Orlando, FL 32816, USA Search for other works by this author on: GSW Google Scholar Timothy D. Glotch; Timothy D. Glotch Department of Geosciences, Stony Brook University, Stony Brook, NY 11794, USA Search for other works by this author on: GSW Google Scholar Benjamin T. Greenhagen; Benjamin T. Greenhagen Planetary Exploration Group, Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA Search for other works by this author on: GSW Google Scholar Juliane Gross; Juliane Gross Department of Earth and Planetary Sciences, Rutgers The State University of New Jersey, Piscataway, NJ 08854 USANASA Johnson Space Center, Houston, TX 77058, USA Search for other works by this author on: GSW Google Scholar James W. Head; James W. Head Department of Earth, Environmental, and Planetary Sciences, Brown University, Providence, RI 02912, USA Search for other works by this author on: GSW Google Scholar Bradley L. Jolliff; Bradley L. Jolliff Department of Earth and Planetary Sciences and the McDonnell Center for Space, Sciences Washington University in St. Louis, St. Louis, MO, 63130, USA Search for other works by this author on: GSW Google Scholar Rachel L. Klima; Rachel L. Klima Planetary Exploration Group, Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA Search for other works by this author on: GSW Google Scholar Tomáš Magna; Tomáš Magna Czech Geological Survey, Klárov 3, CZ-118 21 Prague 1, Czech Republic Search for other works by this author on: GSW Google Scholar Francis M. McCubbin; Francis M. McCubbin NASA Johnson Space Center, Houston, TX 77058, USA Search for other works by this author on: GSW Google Scholar Makiko Ohtake Makiko Ohtake Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshino-dai, Chuo-ku, Sagamihara, Kanagawa 252-5210, Japan Search for other works by this author on: GSW Google Scholar Author and Article Information Stephen M. Elardo The Florida Planets Lab, Department of Geological Sciences, University of Florida, Gainesville, FL 32611, USAEarth and Planets Laboratory, Carnegie Institution for Science, Washington, DC 20015, USA Carle M. Pieters Department of Earth, Environmental, and Planetary Sciences, Brown University, Providence, RI 02912, USA Deepak Dhingra Department of Earth Sciences, Indian Institute of Technology Kanpur, Kalyanpur, Kanpur 208016, Uttar Pradesh, India Kerri L. Donaldson Hanna Atmospheric, Oceanic and Planetary Physics, University of Oxford, Oxford, UKDepartment of Physics, University of Central Florida, Orlando, FL 32816, USA Timothy D. Glotch Department of Geosciences, Stony Brook University, Stony Brook, NY 11794, USA Benjamin T. Greenhagen Planetary Exploration Group, Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA Juliane Gross Department of Earth and Planetary Sciences, Rutgers The State University of New Jersey, Piscataway, NJ 08854 USANASA Johnson Space Center, Houston, TX 77058, USA James W. Head Department of Earth, Environmental, and Planetary Sciences, Brown University, Providence, RI 02912, USA Bradley L. Jolliff Department of Earth and Planetary Sciences and the McDonnell Center for Space, Sciences Washington University in St. Louis, St. Louis, MO, 63130, USA Rachel L. Klima Planetary Exploration Group, Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA Tomáš Magna Czech Geological Survey, Klárov 3, CZ-118 21 Prague 1, Czech Republic Francis M. McCubbin NASA Johnson Space Center, Houston, TX 77058, USA Makiko Ohtake Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshino-dai, Chuo-ku, Sagamihara, Kanagawa 252-5210, Japan selardo@ufl.edu carle_pieters@brown.edu Publisher: Mineralogical Society of America First Online: 04 Dec 2023 Copyright © 2023 by the Mineralogical Society of AmericaMineralogical Society of America Reviews in Mineralogy and Geochemistry (2023) 89 (1): 293–338. https://doi.org/10.2138/rmg.2023.89.07 Article history First Online: 04 Dec 2023 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Stephen M. Elardo, Carle M. Pieters, Deepak Dhingra, Kerri L. Donaldson Hanna, Timothy D. Glotch, Benjamin T. Greenhagen, Juliane Gross, James W. Head, Bradley L. Jolliff, Rachel L. Klima, Tomáš Magna, Francis M. McCubbin, Makiko Ohtake; The Evolution of the Lunar Crust. Reviews in Mineralogy and Geochemistry 2023;; 89 (1): 293–338. doi: https://doi.org/10.2138/rmg.2023.89.07 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyReviews in Mineralogy and Geochemistry Search Advanced Search 1609 AD marked the beginning of the modern scientific exploration of the Moon's crust when Thomas Harriot and later Galileo Galilei made the first recorded maps of the nearside with telescopic observations. Galileo's observations in particular, using a more advanced telescope than was previously available, revealed lunar surface features and topography in detail, effectively refuting the view from Aristotle that the Moon was a perfect, translucent sphere. In 1840, John W. Draper made the first successful photographs of an astronomical object with his daguerreotype photos of the Moon. Increasingly higher quality images of the Moon, first with telescopes and later... You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Research Article| December 01, 2023 Lunar Mare Basaltic Volcanism: Volcanic Features and Emplacement Processes James W. Head; James W. Head Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI 02912, USA Search for other works by this author on: GSW Google Scholar Lionel Wilson; Lionel Wilson Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK Search for other works by this author on: GSW Google Scholar Harald Hiesinger; Harald Hiesinger Institut für Planetologie, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany Search for other works by this author on: GSW Google Scholar Carolyn van der Bogert; Carolyn van der Bogert Institut für Planetologie, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany Search for other works by this author on: GSW Google Scholar Yuan Chen; Yuan Chen Key Laboratory for Lunar and Deep Space Exploration, National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100101, China Search for other works by this author on: GSW Google Scholar James L. Dickson; James L. Dickson Division of Geological and Planetary Science, California Institute of Technology, 1200 E California Blvd, MC 150–21. Pasadena, CA, 91125, USA Search for other works by this author on: GSW Google Scholar Lisa R. Gaddis; Lisa R. Gaddis Lunar and Planetary Institute, 3600 Bay Area Boulevard, Houston, Texas 77058, USA Search for other works by this author on: GSW Google Scholar Junichi Haruyama; Junichi Haruyama Institute of Space and Astronautical Science, JAXA, Japan (3–1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252–5210, Japan) Search for other works by this author on: GSW Google Scholar Erica R. Jawin; Erica R. Jawin Smithsonian Institution National Museum of Natural History, Department of Mineral Sciences, PO Box 37012, Washington, DC 20013–7012, USA Search for other works by this author on: GSW Google Scholar Lauren M. Jozwiak; Lauren M. Jozwiak Johns Hopkins Applied Physics Laboratory, 11100 Johns Hopkins Rd, Laurel, MD 20723, USA Search for other works by this author on: GSW Google Scholar Chunlai Li; Chunlai Li Key Laboratory for Lunar and Deep Space Exploration, National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100101, China Search for other works by this author on: GSW Google Scholar Jianzhong Liu; Jianzhong Liu Center for Lunar and Planetary Sciences, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China Search for other works by this author on: GSW Google Scholar Tomokatsu Morota; Tomokatsu Morota Department of Earth and Planetary Science, University of Tokyo, Bunkyō-ku, Tokyo, Japan Search for other works by this author on: GSW Google Scholar Debra H. Needham; Debra H. Needham National Aeronautics and Space Administration Headquarters, Washington, D.C. 20546, USA Search for other works by this author on: GSW Google Scholar Lillian R. Ostrach; Lillian R. Ostrach US Geological Survey Astrogeology Science Center, 2255 N. Gemini Drive, Flagstaff, AZ USA Search for other works by this author on: GSW Google Scholar Carle M. Pieters; Carle M. Pieters Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI 02912, USA Search for other works by this author on: GSW Google Scholar Tabb C. Prissel; Tabb C. Prissel Astromaterials Research and Exploration Science Division, NASA Johnson Space Center, Houston, TX 77058 USA Search for other works by this author on: GSW Google Scholar Yuqi Qian; Yuqi Qian Planetary Science Institute, China University of Geosciences, Wuhan, 430074, China Search for other works by this author on: GSW Google Scholar Le Qiao; Le Qiao Institute of Space Science, Shandong University, Weihai, 264209, China Search for other works by this author on: GSW Google Scholar Malcolm R. Rutherford; Malcolm R. Rutherford Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI 02912, USA Search for other works by this author on: GSW Google Scholar David R. Scott; David R. Scott Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI 02912, USA Search for other works by this author on: GSW Google Scholar Jennifer L. Whitten; Jennifer L. Whitten Department of Earth and Environmental Sciences, Tulane University, New Orleans, LA 70118 USA Search for other works by this author on: GSW Google Scholar Long Xiao; Long Xiao Planetary Science Institute, China University of Geosciences, Wuhan, 430074, China Search for other works by this author on: GSW Google Scholar Feng Zhang; Feng Zhang National Space Science Center, No. 1 Nanertiao, Zhongguancun, Haidian District, Beijing, China Search for other works by this author on: GSW Google Scholar Ouyang Ziyuan Ouyang Ziyuan Key Laboratory for Lunar and Deep Space Exploration, National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100101, China Search for other works by this author on: GSW Google Scholar Author and Article Information James W. Head Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI 02912, USA Lionel Wilson Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK Harald Hiesinger Institut für Planetologie, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany Carolyn van der Bogert Institut für Planetologie, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany Yuan Chen Key Laboratory for Lunar and Deep Space Exploration, National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100101, China James L. Dickson Division of Geological and Planetary Science, California Institute of Technology, 1200 E California Blvd, MC 150–21. Pasadena, CA, 91125, USA Lisa R. Gaddis Lunar and Planetary Institute, 3600 Bay Area Boulevard, Houston, Texas 77058, USA Junichi Haruyama Institute of Space and Astronautical Science, JAXA, Japan (3–1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252–5210, Japan) Erica R. Jawin Smithsonian Institution National Museum of Natural History, Department of Mineral Sciences, PO Box 37012, Washington, DC 20013–7012, USA Lauren M. Jozwiak Johns Hopkins Applied Physics Laboratory, 11100 Johns Hopkins Rd, Laurel, MD 20723, USA Chunlai Li Key Laboratory for Lunar and Deep Space Exploration, National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100101, China Jianzhong Liu Center for Lunar and Planetary Sciences, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China Tomokatsu Morota Department of Earth and Planetary Science, University of Tokyo, Bunkyō-ku, Tokyo, Japan Debra H. Needham National Aeronautics and Space Administration Headquarters, Washington, D.C. 20546, USA Lillian R. Ostrach US Geological Survey Astrogeology Science Center, 2255 N. Gemini Drive, Flagstaff, AZ USA Carle M. Pieters Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI 02912, USA Tabb C. Prissel Astromaterials Research and Exploration Science Division, NASA Johnson Space Center, Houston, TX 77058 USA Yuqi Qian Planetary Science Institute, China University of Geosciences, Wuhan, 430074, China Le Qiao Institute of Space Science, Shandong University, Weihai, 264209, China Malcolm R. Rutherford Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI 02912, USA David R. Scott Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI 02912, USA Jennifer L. Whitten Department of Earth and Environmental Sciences, Tulane University, New Orleans, LA 70118 USA Long Xiao Planetary Science Institute, China University of Geosciences, Wuhan, 430074, China Feng Zhang National Space Science Center, No. 1 Nanertiao, Zhongguancun, Haidian District, Beijing, China Ouyang Ziyuan Key Laboratory for Lunar and Deep Space Exploration, National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100101, China Publisher: Mineralogical Society of America First Online: 04 Dec 2023 Copyright © 2023 by the Mineralogical Society of AmericaMineralogical Society of America Reviews in Mineralogy and Geochemistry (2023) 89 (1): 453–507. https://doi.org/10.2138/rmg.2023.89.11 Article history First Online: 04 Dec 2023 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation James W. Head, Lionel Wilson, Harald Hiesinger, Carolyn van der Bogert, Yuan Chen, James L. Dickson, Lisa R. Gaddis, Junichi Haruyama, Erica R. Jawin, Lauren M. Jozwiak, Chunlai Li, Jianzhong Liu, Tomokatsu Morota, Debra H. Needham, Lillian R. Ostrach, Carle M. Pieters, Tabb C. Prissel, Yuqi Qian, Le Qiao, Malcolm R. Rutherford, David R. Scott, Jennifer L. Whitten, Long Xiao, Feng Zhang, Ouyang Ziyuan; Lunar Mare Basaltic Volcanism: Volcanic Features and Emplacement Processes. Reviews in Mineralogy and Geochemistry 2023;; 89 (1): 453–507. doi: https://doi.org/10.2138/rmg.2023.89.11 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyReviews in Mineralogy and Geochemistry Search Advanced Search Volcanism is a fundamental process in the geological evolution of the Moon, providing clues to the composition and structure of the mantle, the location and duration of interior melting, the nature of convection and lunar thermal evolution. Progress in understanding volcanism has been remarkable in the short 60-year span of the Space Age. Before Sputnik 1 in 1957, the lunar farside was unknown, the origin of the dark lunar maria was debated (sedimentary or volcanic), and significant controversy surrounded the question of how the multitude of craters on the surface formed. Was the Moon formed hot or cold, was the... You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

The Moon is generally depleted in volatile elements and this depletion extends to the surface where the most abundant mineral, anorthite, features <6 ppm H2O. Presumably the other nominally anhydrous minerals that dominate the mineral composition of the global surface-olivine and pyroxene-are similarly depleted in water and other volatiles. Thus the Moon is tabula rasa for the study of volatiles introduced in the wake of its origin. Since the formation of the last major basin (Orientale), volatiles from the solar wind, from impactors of all sizes, and from volatiles expelled from the interior during volcanic eruptions have all interacted with the lunar surface, leaving a volatile record that can be used to understand the processes that enable processing, transport, sequestration, and loss of volatiles from the lunar system. Recent discoveries have shown the lunar system to be complex, featuring emerging recognition of chemistry unanticipated from the Apollo era, confounding issues regarding transport of volatiles to the lunar poles, the role of the lunar regolith as a sink for volatiles, and the potential for active volatile dynamics in the polar cold traps. While much has been learned since the overturn of the "Moon is dry" paradigm by innovative sample and spacecraft measurements, the data point to a more complex lunar volatile environment than is currently perceived.

The primary objective of this work is to constrain the physical and chemical effects of ilmenite on the spectral properties of high-titanium lunar basalts. Here we use a combination of electron probe microanalysis, x-ray diffraction and VIS-NIR spectroscopy to characterize a suite of Apollo 17 High-Ti lunar basalts and a suite of synthetic laboratory derived binary mixtures to further understand the mixing systematics of opaque Fe-Ti oxides in a transparent silicate matrix. We demonstrate how the texture (particle size and shape) and compo-sition (Fe-Mg content) of ilmenite exhibit strong controls over the spectral parameters of bulk basalts in the VIS-NIR wavelength range. We show that the presence of fine-grained ilmenite as opposed to coarse-grained ilmenite in high-Ti basalts causes suppression of pyroxene, olivine, and plagioclase absorption features, lowers reflectance values, and induces a stronger 'red' spectral slope at wavelengths > 1.8 mu m. These effects are considerably stronger for samples with fine-grained ilmenite crystals compared with coarse-grained samples that have similar ilmenite abundance. In addition, we show that minor variations in the Mg2+ content of ilmenite significantly alters the strength of the 1 mu m feature and the slope above 1.8 mu m, which similarly affects the spectral parameters of the bulk basalt. Our results indicate that lunar basalts with lower abundance of fine-grained ilmenite with slightly higher Mg content could exhibit a spectrum with an apparently stronger ilmenite signature when compared to basalts with more abundant, coarser ilmenite. Results presented here suggest that the accuracy of spectral mixing models of remotely sensed data on the Moon would improve by incorporating additional spectral end-members of ilmenite to better represent the compositional variability.

Selected in 2019 as a NASA SIMPLEx mission, Lunar Trailblazer is in implementation for flight system delivery at the end of 2022. The mission's goal is to understand the form, abundance, and distribution of water on the Moon and the lunar water cycle. Lunar Trailblazer also collects data of candidate landing sites to inform planning for future human and robotic exploration of the Moon and evaluate the potential for in situ resource utilization. Lunar Trailblazer's two science instruments, the High-resolution Volatiles and Minerals Moon Mapper (HVM3) and the Lunar Thermal Mapper (LTM) provide simultaneous high-resolution spectral imaging data to map OH/water, crustal composition, and thermophysical properties from a $100\pm 30$ km lunar polar orbit. The ∼210-kg flight system deploys from an ESPA Grande and utilizes a ∼1000 m/s $\Delta\mathrm{V}$ hydrazine chemical propulsion system, similar to that employed by GRAIL. Trailblazing elements include the novel state-of-the-art dataset collected at substantially reduced price point, fully geographically co-registered data products delivered to the Planetary Data System, planetary mission team demographics, Caltech campus mission operations, and student staffing of select mission ops roles. Lunar Trailblazer's pioneering development is providing key lessons learned for future planetary small spacecraft.

Whitepaper #107 submitted to the Planetary Science and Astrobiology Decadal Survey 2023-2032. Topics: atmospheric/exospheric evolution; Mercury and/or the Moon; other science themes: volatile evolution

Ceres' regolith contains water ice that has receded in response to insolation‐driven sublimation. Specially targeted, high spatial‐resolution measurements of hydrogen by Dawn's Gamma Ray and Neutron Detector (GRaND) reveal elevated hydrogen concentrations in and around Occator, a young, 90 km diameter, complex crater located at 19.82°N where near‐surface ice is not expected. The excess hydrogen can be explained by impact excavation of water‐rich outer crustal materials and their emplacement in the crater floor and ejecta blanket. This is supported by thermophysical models that show water ice could survive at sub‐meter depths, given Occator's relatively young age (∼20 Myr). We hypothesize that the regolith can be replenished with ice from large impacts and that this process partially controls the distribution and depth of near surface ice. This is supported by results from Occator and similarities in the global distribution of hydrogen and the pattern of large craters (20–100 km diameter).

The NanoSWARM mission concept is a detailed investigation of particles and magnetic fields to help characterize the surfaces of airless planetary bodies, their volatile element distributions, and their geophysical histories.NanoSWARM investigates unique regions in the solar system where these processes come together: lunar swirls.NanoSWARM would be the first demonstration of a planetary-class carrier vehicle equipped with dozens of nanosatellites, each capable of performing measurements either too risky or difficult for the carrier.This architecture greatly facilitates contributed nanosatellites and complete sub-missions from other nations, students, or participating scientists.NanoSWARM was proposed to the Discovery program in 2019.It was one of 6 missions that received the highest possible ranking of Category 1, but it did not move forward to Phase A.The commercial space flight community is well on its way toward mass production of small spacecraft.An openness within the planetary community toward building dozens of instruments or spacecraft could open up entirely new regimes of measurement in space. Science overview: NanoSWARM (NanoSatellites for Space Weathering, Surface Water, SolarWind, And Remanent Magnetism) uses a new type of space mission architecture to address four complementary science goals, becoming, in effect, four missions in one.NanoSWARM launches 19 NanoSatellites (plus spares) to fly just above the surface at five target sites spread across the Moon's near and far sides.This architecture permits a science investigation of substantial breadth and depth, beyond what could be accomplished with a single orbiter, rover, or lander.NanoSWARM's first goal is to elucidate the mechanisms of space weathering -the alteration of an airless body's optical properties due to solar wind and micrometeoroid bombardment.This ubiquitous process affects spectral data from 0.1-10 microns and, thereby, our ability to determine the compositions of bodies ranging from Mercury to asteroids.Despite decades of study, we do not have a complete model for how space weathering operates.In particular, the relative contributions from micrometeoroids and solar wind flux and the influence of local soil mineralogy on the optical effects are not completely understood.To address this problem, NanoSWARM investigates unique locations on the Moon where solar wind flux is modified while the micrometeoroid flux and mineralogy remain constant: lunar swirls (Fig. 1).The M 3 instrument on Chandrayaan-1 as well as Diviner and LAMP on Lunar Reconnaissance Orbiter (LRO) quantified the spectral variations across these features.By performing the first spatially resolved near-surface solar wind flux measurements across multiple swirls with different soil iron contents, NanoSWARM quantitatively resolves how the solar wind affects the optical properties of the Moon and similar silicate bodies.NanoSWARM's second goal is to constrain how near-surface water forms and is distributed on airless bodies like the Moon, Mercury, and asteroids.Lunar Prospector and Chandrayaan-1 made landmark discoveries of two different water populations: a surficial one that appears at all latitudes and a polar one that may extend to tens of meters below the surface.The connections between these two populations are unknown.NanoSWARM takes advantage of the most recent discovery that lunar magnetic anomalies are correlated with low concentrations of surfacebound OH/H2O ((Li & Milliken, 2017); Fig. 2).By measuring the in-situ solar wind proton flux at magnetic anomalies, NanoSWARM helps quantify how protons are converted into these products.Furthermore, NanoSWARM makes very low altitude measurements of neutrons above the poles to quantify hydrogen distributions inside craters, but this measurement is not emphasized here.

Understanding the origin and evolution of the lunar volatile system is not only compelling lunar science, but also fundamental Solar System science. This white paper (submitted to the US National Academies' Decadal Survey in Planetary Science and Astrobiology 2023-2032) summarizes recent advances in our understanding of lunar volatiles, identifies outstanding questions for the next decade, and discusses key steps required to address these questions.

Introduction: Recent work has demonstrated that infrared spectra measured in the 4-8 μm “cross-over” range are a useful tool for determining the Mg# of olivine [1]. Olivine has two strong, distinct bands at 5.6 and 6.0 μm (Fig. 1) that shift systematically to longer wavelengths with increasing Fe content, allowing Mg# to be determined for reflectance spectra of pure olivine samples in a laboratory setting within +/-10 mol% [1]. Although Mg# trends have been studied in pure olivine in the “cross-over” region, it remains unknown how the presence of other minerals affects these spectral bands and their use as a diagnostic tool for Mg#. Investigating “cross-over” spectra of olivine-bearing particulate mixtures is therefore essential for constraining the opportunities and limitations of this technique in the lunar context as detectors become available for lunar missions. We are preparing a suite of particulate mixtures of forsterite and anorthite with particle size distributions approximating those of the lunar regolith, which we will measure in reflectance and in emissivity in a simulated lunar environment. Measurements of these samples will provide a strong foundation for interpretation of spectra measured from future spacecraft instruments. As a proof of concept for this study, we also examine emissivity measurements of a similar suite of fine-particulate (<32 μm) anorthiteforsterite mixtures. Background: The “cross-over” region is the wavelength range of the infrared where the volume scattering of photons in the visible-near infrared (VNIR 0.5-3 μm) transitions to the surface scattering of photons in the mid-infrared (MIR 8-15 μm). In the inner Solar System, the “cross-over” region for silicate minerals also generally coincides with the transition between the dominance of reflected solar photons in VNIR and thermally emitted photons in the MIR. The “cross-over” signatures of silicate minerals are hypothesized to arise as overtone-combination bands of fundamental vibrations at longer wavelengths [2]. Since both reflection and emission are expected to contribute to the radiance measured on the Moon in the 4-8 μm range [3], it is necessary to examine both reflectance and emissivity spectra when assessing the “cross-over” character of mineral samples. It has been demonstrated that features seen in emissivity and reflectance spectra of identical samples in the “crossover” region can be related to each other through Kirchhof’s law (E=1–R, where E is emissivity and R is reflectance), meaning that reflectance and emissivity spectra may be directly compared with each other [1].