A novel geological framework is presented to address the origin of Orthopyroxene, Olivine, Mg-spinel (OOS) lithologies on the Moon, an emerging component of the lunar crust. The new framework can explain multiple remote sensing observations including the rare occurrence of OOS lithologies in close proximity, lack of mafic mineral association with Mg-spinel lithology and the contrasting observation of mafic mineral association with Mg-spinel in returned lunar samples. We further report new OOS exposures at Thomson crater and present the first remote-sensing-based evidence of mafic mixing among various OOS components. Collectively, the new framework and observations provide a testable set of geological scenarios to understand the origin and diversity of the OOS lithologies and their role in lunar crustal diversity. Future missions would directly benefit from this knowledge towards collecting the best OOS lithology samples, currently absent from the returned lunar sample collection.

The spatial distribution of Mg-spinel lithology at South Pole-Aitken (SPA) basin is revealed by systematic mineralogical survey along the basin rings. We report Ingenii-Thomson region as a Mg-spinel anomaly, having the largest number of exposures based on newly identified and previously reported occurrences on the Moon. The timing of Mg-spinel formation is constrained by using SPA impact as a key geological time marker. Post-SPA origin of this lithology is favored in this region due to the general lack of pervasive Mg-spinel occurrences along basin rings, being the deepest exposures of the pre-SPA crust. Our detailed mineralogical analyses also highlight several detections of Mg-spinel lithology exhibiting weak 1,000 nm absorption band, emphasizing the need for a detailed analysis of such locations. Collectively, these salient findings have important implications for understanding the compositional diversity of Mg-spinel lithology, refinement of the formation models and determining the role of Mg-spinel lithology in the lunar crustal evolution.

We present a framework to study regolith segregation on rubble-pile asteroids-self-gravitating granular aggregates-due to seismic shaking induced by impacts sustained during their lifetimes. We first relate the amplitude and frequency of surface vibrations to the location and severity of an impact, and the rubble body's geometry and bulk properties. For illustration, the body is taken to be an ellipsoid with size and spin close to that of Itokawa, although more complex asteroid shapes may be incorporated. We then model the body's collisional history stochastically given the variability in the impact activity on an asteroid. Finally, we use discrete element simulations to investigate the regolith's response to impacts. In these simulations, in any sample collisional history, every time an impact occurs, a bin filled with a grain mixture and located at the region of interest on the asteroid is vibrated at that impact's associated amplitude and frequency. Using this framework, we find that impact-driven seismicity is sufficient to drive size segregation on small rubble-piles, but the segregation quality depends on several aspects, e.g. total impact energy supplied, placement of the region of interest, bulk wave speed and seismic diffusivity.

Planetary geologic maps are crucial tools for understanding the geological features and processes of solid bodies in the Solar System. Over the past six decades, best practices in planetary geologic mapping have emphasized clear and objective observation, geological interpretation, multi-sensor fusion, and iterative revision of maps based on new data. We summarize here four ways in which maps serve as indispensable instruments for scientific investigation, from enhancing observations to interrogating surface processes. With respect to space exploration, we underscore the role of planetary geologic maps as tools to link testable, hypothesis-driven science to exploration goals and provide actionable information for hazard identification, resource evaluation, sample collection, and potential infrastructure development. To further advance the field of planetary geologic mapping, international collaboration is essential. This includes sharing data and maps through FAIR (findable, accessible, interoperable, and reusable) platforms, establishing standardized mapping practices, promoting diverse nomenclature, and fostering continued cooperation in space exploration.

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 Impact Features and Processes Gordon R. Osinski; Gordon R. Osinski Department of Earth Sciences, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, CanadaInstitute for Earth and Space Exploration, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, CanadaCanadian Lunar Research Network, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, Canada gosinski@uwo.ca Search for other works by this author on: GSW Google Scholar H. Jay Melosh; H. Jay Melosh Department of Earth Sciences, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, Canada Search for other works by this author on: GSW Google Scholar Jeff Andrews-Hanna; Jeff Andrews-Hanna Lunar and Planetary Lab, University of Arizona, Tucson, AZ 85721, USA Search for other works by this author on: GSW Google Scholar David Baker; David Baker Planetary Geology, Geophysics and Geochemistry Lab, Code 698, Goddard Space Flight Center, Greenbelt, MD 20771, USA Search for other works by this author on: GSW Google Scholar Brett Denevi; Brett Denevi Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723, USA 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 Rebecca Ghent; Rebecca Ghent Planetary Science Institute, 1700 E. Fort Lowell, Tucson, AZ 85719, USA Search for other works by this author on: GSW Google Scholar Paul O. Hayne; Paul O. Hayne Department of Astrophysical and Planetary Sciences, University of Colorado Boulder, CO 80309, USA Search for other works by this author on: GSW Google Scholar Patrick Hill; Patrick Hill Department of Earth Sciences, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, CanadaInstitute for Earth and Space Exploration, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, CanadaCanadian Lunar Research Network, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, Canada Search for other works by this author on: GSW Google Scholar Peter B. James; Peter B. James Department of Geosciences, Baylor University, Waco, TX 76798, USA Search for other works by this author on: GSW Google Scholar Steven Jaret; Steven Jaret American Museum of Natural History, New York, New York, 10024, USA Search for other works by this author on: GSW Google Scholar Brandon Johnson; Brandon Johnson Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI 02912, USA Search for other works by this author on: GSW Google Scholar Thomas Kenkmann; Thomas Kenkmann Institut fur Geound Umweltnaturwissenschaften, Albert-Ludwigs-Universität, Freiburg, Freiberg, Germany Search for other works by this author on: GSW Google Scholar David Kring; David Kring Center for Lunar and Space Exploration, Lunar and Planetary Institute, 3600 Bay Area Blvd., Houston, TX 77058, USA Search for other works by this author on: GSW Google Scholar Prasun Mahanti; Prasun Mahanti School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85281, USA Search for other works by this author on: GSW Google Scholar David Minton; David Minton Earth Atmospheric and Planetary Sciences, Purdue University, West Lafayette IN 47907, USA Search for other works by this author on: GSW Google Scholar Catherine D. Neish; Catherine D. Neish Department of Earth Sciences, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, CanadaInstitute for Earth and Space Exploration, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, CanadaCanadian Lunar Research Network, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, Canada Search for other works by this author on: GSW Google Scholar Greg Neumann; Greg Neumann Planetary Geology, Geophysics and Geochemistry Lab, Code 698, Goddard Space Flight Center, Greenbelt, MD 20771, USA Search for other works by this author on: GSW Google Scholar Jeff Plescia; Jeff Plescia Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723, USA Search for other works by this author on: GSW Google Scholar Ross W. K. Potter; Ross W. K. Potter Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI 02912, USA Search for other works by this author on: GSW Google Scholar Jim Richardson; Jim Richardson Planetary Science Institute, 1700 E. Fort Lowell, Tucson, AZ 85719, USA Search for other works by this author on: GSW Google Scholar Elizabeth A. Silber; Elizabeth A. Silber Department of Earth Sciences, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, CanadaInstitute for Earth and Space Exploration, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, CanadaCanadian Lunar Research Network, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, Canada Search for other works by this author on: GSW Google Scholar Jason M. Soderblom; Jason M. Soderblom Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA Search for other works by this author on: GSW Google Scholar Michael Zanetti; Michael Zanetti Department of Earth Sciences, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, CanadaInstitute for Earth and Space Exploration, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, CanadaCanadian Lunar Research Network, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, CanadaNASA George C. Marshall Space Flight Center, National Space Science and Technology Center, 320 Sparkman Drive, Huntsville, AL 35805, USA Search for other works by this author on: GSW Google Scholar Nicolle Zellner Nicolle Zellner Department of Physics, Albion College, Albion MI 49224, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Gordon R. Osinski Department of Earth Sciences, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, CanadaInstitute for Earth and Space Exploration, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, CanadaCanadian Lunar Research Network, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, Canada H. Jay Melosh Department of Earth Sciences, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, Canada Jeff Andrews-Hanna Lunar and Planetary Lab, University of Arizona, Tucson, AZ 85721, USA David Baker Planetary Geology, Geophysics and Geochemistry Lab, Code 698, Goddard Space Flight Center, Greenbelt, MD 20771, USA Brett Denevi Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723, USA Deepak Dhingra Department of Earth Sciences, Indian Institute of Technology Kanpur, Kalyanpur, Kanpur 208016, Uttar Pradesh, India Rebecca Ghent Planetary Science Institute, 1700 E. Fort Lowell, Tucson, AZ 85719, USA Paul O. Hayne Department of Astrophysical and Planetary Sciences, University of Colorado Boulder, CO 80309, USA Patrick Hill Department of Earth Sciences, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, CanadaInstitute for Earth and Space Exploration, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, CanadaCanadian Lunar Research Network, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, Canada Peter B. James Department of Geosciences, Baylor University, Waco, TX 76798, USA Steven Jaret American Museum of Natural History, New York, New York, 10024, USA Brandon Johnson Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI 02912, USA Thomas Kenkmann Institut fur Geound Umweltnaturwissenschaften, Albert-Ludwigs-Universität, Freiburg, Freiberg, Germany David Kring Center for Lunar and Space Exploration, Lunar and Planetary Institute, 3600 Bay Area Blvd., Houston, TX 77058, USA Prasun Mahanti School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85281, USA David Minton Earth Atmospheric and Planetary Sciences, Purdue University, West Lafayette IN 47907, USA Catherine D. Neish Department of Earth Sciences, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, CanadaInstitute for Earth and Space Exploration, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, CanadaCanadian Lunar Research Network, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, Canada Greg Neumann Planetary Geology, Geophysics and Geochemistry Lab, Code 698, Goddard Space Flight Center, Greenbelt, MD 20771, USA Jeff Plescia Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723, USA Ross W. K. Potter Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI 02912, USA Jim Richardson Planetary Science Institute, 1700 E. Fort Lowell, Tucson, AZ 85719, USA Elizabeth A. Silber Department of Earth Sciences, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, CanadaInstitute for Earth and Space Exploration, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, CanadaCanadian Lunar Research Network, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, Canada Jason M. Soderblom Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA Michael Zanetti Department of Earth Sciences, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, CanadaInstitute for Earth and Space Exploration, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, CanadaCanadian Lunar Research Network, University of Western Ontario, 1151 Richmond St., London, ON, N6A 5B7, CanadaNASA George C. Marshall Space Flight Center, National Space Science and Technology Center, 320 Sparkman Drive, Huntsville, AL 35805, USA Nicolle Zellner Department of Physics, Albion College, Albion MI 49224, USA gosinski@uwo.ca 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): 339–371. https://doi.org/10.2138/rmg.2023.89.08 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 Gordon R. Osinski, H. Jay Melosh, Jeff Andrews-Hanna, David Baker, Brett Denevi, Deepak Dhingra, Rebecca Ghent, Paul O. Hayne, Patrick Hill, Peter B. James, Steven Jaret, Brandon Johnson, Thomas Kenkmann, David Kring, Prasun Mahanti, David Minton, Catherine D. Neish, Greg Neumann, Jeff Plescia, Ross W. K. Potter, Jim Richardson, Elizabeth A. Silber, Jason M. Soderblom, Michael Zanetti, Nicolle Zellner; Lunar Impact Features and Processes. Reviews in Mineralogy and Geochemistry 2023;; 89 (1): 339–371. doi: https://doi.org/10.2138/rmg.2023.89.08 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 This chapter is dedicated to H. Jay Melosh who tragically passed away during this endeavor. From his earliest publications on the concept of acoustic fluidization, to the publication of his landmark book Impact Cratering—A Geologic Process in 1989, to his latest contributions to the paper by Trowbridge et al. (2020) cited herein on understanding of the South Pole-Aiken basin, Jay's contributions to the understanding of the impact cratering process, and planetary surface processes in general, are unparalleled. His passing leaves a huge void in the community and he will be sorely missed. Impact craters are the Moon's quintessential landform. First... You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

To better understand the necessary triggers for the origin of the lunar boulder tracks, we report 650 tracks from the ~73 km in diameter Finsen crater. The tracks were identified on the crater wall and the central peak region of the Finsen crater, located within the South Pole -Aitken basin on the lunar far side. In this manuscript, we assessed two main possibilities of triggers, 1) ground shakings by the recent meteorite impact, and 2) ground shaking from recent fault reactivation associated with the lobate scarps identified inside and in the vicinity of the Finsen crater. Our assessments revealed that the impact-induced seismicity could have generated the moonquake with the maximum moment magnitude (M-W) 4.63. We also estimated that the moonquakes excited by the movements along the lobate scarps had an estimated cumulative (or maximum possible) moment magnitude (M-W) up to 6.86 and 6.90, i.e., for the basaltic and noritic basement respectively. Considering the location of the Finsen crater positioned over the structural discontinuity along the boundary of the central and mid rings of the South Pole -Aitken basin and higher moment magnitude generated from the fault movements, we propose that the region is potentially seismotectonically active, and reactivation of pre-existing faults possibly triggered/triggers the necessary ground motion for the boulders to initiate their movements. However, impact-induced ground shakings and deep-focused moonquakes also remain possibilities for triggers.

K. Kawai, H. Okuda, Z. Xiao, and D. Dhingra. 1 Department of Earth and Planetary Science, School of Science, University of Tokyo, Hongo 7-3-1, Bunkyo, Tokyo 113-0033, Japan (trishit@eps.s.u-tokyo.ac.jp), International Research School of Planetary Sciences, Università G. d'Annunzio, Viale Pindaro 42, 65127, Pescara, Italy, 3 Department of Ocean Floor Geoscience, Atmosphere and Ocean Research Institute, University of Tokyo, Kashiwanoha 5-1-5, Kashiwa, Chiba 277-8564, Japan, 4 Planetary Environmental and Astrobiological Research Laboratory, School of Atmospheric Sciences, Sun Yat-sen University, Zhuhai, China, 5 Department of Earth Sciences, Indian Institute of Technology Kanpur, Kanpur, UP 208016, India.

Machine learning is emerging as a promising technology with immense applications in various stages of planetary missions. Our focus is to use reflectance data obtained remotely from the Moon surface that can be used for detailed compositional mapping. These datasets need to be adequately preprocessed by removing noise and artifacts before performing an analysis. A traditional way of data preprocessing is to define a set of rules to remove unwanted effects but these methods totally rely on specific information available to the user. Such an approach can significantly improve the quality of the data but unidentified effects may still persist and influence any further analysis. To mitigate this problem, here, we propose to use a new approach which uses Machine Learning algorithms (MLAs) for the preprocessing of all kind of remote sensing data which identified sand filter out unsuitable spectra in the data. We applied MLAs to hyperspectral datasets obtained by the Infrared Spectrometer SIR-2 onboard Chandrayaan-1. In this work, data preprocessing is implemented as a supervised classification problem which aims to classify an input spectrum into desirable/undesirable ones labeled as "GOOD’ and "BAD". The approach was used to filter good spectra from the set of 173 SIR-2 orbits comprising of a total of ~2 million spectra. The methodology followed was a two-stage methodology. In the first stage, subset (~1 million) of data was sampled using systematic sampling. The spectra in the sub-set was manually annotated and different supervised learning approaches namely Logistic regression, Decision tree, KNN, ensemble were applied on this labeled data. On comparing their efficiency using performance metrics, we found five-algorithm voting based ensemble method to be best in terms of accuracy (99.8%) as well as reliability. In the second stage this approach was applied on the remaining unlabeled data to predict the class of spectrum and decide on the usability of that spectrum. As a final outcome, the five-algorithm ensemble approach, classified a total of ~1.35 million spectra as „Good spectra’ and remaining ~1.04 million spectra as ‘Bad spectra’. One of the strength of this approach is that we can obtain comparative performance using very less number of labeled samples. This work demonstrates that our proposed method is suitable for the preprocessing of huge datasets obtained from different missions and of varied nature.

We investigate the dynamics of regolith on rubble-pile asteroids to explain granular processes observed in reality. In particular, we explain how the appearance of boulders on the surface of asteroid Itokawa could have resulted from a size sorting process in granular media called the Brazil Nut Effect (BNE). The Discrete Element Method (DEM) is implemented to perform numerical simulations of the BNE in a micro-gravity environment caused by inter-particle collisions during seismic vibrations. Firstly, we present the results of how the BNE depends on the magnitude of surface gravity. It is estimated that segregation processes on Itokawa occur over much longer time-scales (in the order of a few hundred years) than the same processes would require in the presence of a strong gravitational field, like on Earth. Secondly, we also find that the size sorting could also result from kinetic sieving encountered during granular avalanches. Finally, we discuss how the void-filling mechanism becomes more efficient when there is a higher relative size difference between the boulders and the surrounding grains. Our model has important implications in understanding the resurfacing of Itokawa by trying to explain one of the many complex geophysical processes that occur in such unique conditions.

INFRARED SPECTROMETER (IIRS). Satadru Bhattacharya 1* , Aditya Kumar Dagar 1 , Arup Banerjee 1 , Ankush Kumar 1 , Amitabh 1 , K Suresh 1 , Ajay Prashar 1 , Abhishek Patil 1 , Arup Roy Chowdhury 1 , Anish R. Saxena 1 , S. Gomathi 2 , Vijaysree 2 , Prakash Chauhan 3 , Mamta Chauhan 3 , Sumit Pathak 4,5 , Deepak Dhingra 6 , Shovan Lal Chattoraj 3 , Himela Moitra 4 and Saibal Gupta 4 . 1 Space Applications Centre, Indian Space Research Organisation (ISRO), Ahmedabad – 380015, India. 2 U. R. Rao Satellite Centre, ISRO, Bengaluru – 560017, India. 3 Indian Institute of Remote Sensing, ISRO, Dehradun – 248001, India. 4 Indian Institute of Technology, Kharagpur – 721302, India. 5 Dept. of Geology, Banasthali University, Rajasthan – 304022, India. 6 Indian Institute of Technology, Kanpur – 208016, India ( * satadru@sac.isro.gov.in).

Introduction: Gravity Recovery and Interior Laboratory (GRAIL) mission has recently revealed evidence for large scale occurrence of magmatic intrusions in the form of linear gravity anomalies or LGAs [1]. The largest of these intrusions span several hundred kilometers in length and extend for several kilometers in width. We report here potential near surface expressions of some of these geophysical anomalies which have direct implications for understanding the emplacement of these massive and spatially pervasive features. Data and Methods: We have utilized coordinated imaging and spectral datasets from recent missions in conjunction with the reported gravity anomalies to evaluate spatial correlations. Imaging data from Wide Angle Camera (WAC) at 100 meter per pixel and Narrow Angle Camera (NAC) at 0.5-1 m per pixel from Lunar Reconnaissance Orbiter (LRO) mission and Terrain Camera (TC) at 10 meter per pixel from Selenological and Engineering Explorer (SELENE) mission have been utilized to study the geomorphological character of the region around LGAs. Hyperspectral data from Moon Mineralogy Mapper (M) on Chandrayaan1 mission has been utilized to further evaluate the mineralogical signatures of geomorphologically interesting locations in the proximity of LGAs. New Findings: We report the occurrence of floor fractured craters (FFCs) in proximity to some of the LGA segments. FFCs are known to have formed by the modification of impact craters by subsequent intrusive magmatic activity [e.g. 2, 3]. We describe here four such occurrences which seem to be linked to the nearby LGA segments and could therefore provide additional information about the associated LGA: a) Crater Karpinskiy (91 km dia.): It is located in close proximity to the largest LGA in the northern high latitudes (Figure 1). The crater is separated from the LGA by ~50 km. Recent work by [4] reported the crater to have a feldspathic mineralogy along with strong hydration signatures. Karpinskiy is flanked by many large craters, similar to its size but none show evidence of any floor fractures. b) Crater Montgolfier P (36 km dia.) and Unnamed Crater (31.2 km dia.): These two craters are located at mid-latitudes in the northern hemisphere, at the far southern end of the largest LGA (same as the one associated with Karpinskiy). Their spatial relations indicate that any association with LGA would be with a subsegment rather than the main segment. Interestingly, both craters exhibit a circular exposure of mafic material on the floor (Figure 2). With the surrounding region being largely feldspathic, the mafic

On day 138 of 2010, the plume of dust and gas emerging from Enceladus' South Polar Terrain passed between the Sun and the Cassini spacecraft. This solar occultation enabled Cassini's Ultraviolet Imaging Spectrograph (UVIS) and the Visual and Infrared Mapping Spectrometer (VIMS) to obtain simultaneous measurements of the plume's gas and dust components along the same lines of sight. The UVIS measurements of the plume's gas content are described in Hansen et al. (2011, GRL 38:11202) , while this paper describes the VIMS data and the information they provide about the plume's particle content. Together, the VIMS and UVIS measurements reveal that the plume material above Baghdad and Damascus sulci has a dust-to-gas mass ratio that is roughly an order of magnitude higher than the material above Alexandria and Cairo sulci. Similar trends in the plume's dust-to-gas ratio are also found in data obtained when Cassini flew through the plume in 2009, during which time the Ion and Neutral Mass Spectrometer (INMS), Radio and Plasma Wave Science instrument (RPWS) and Cosmic Dust Analyzer (CDA) instruments made in-situ measurements of the plume's gas and dust densities (Dong et al. 2015 JGR 120:915-937). These and other previously-published systematic differences in the material erupting from different fissures likely reflect variations in subsurface conditions across Encealdus' South Polar Terrain.