Program and Abstracts Lunar Polar Volatiles August 7–9, 2018 • Laurel, Maryland Organizers Lunar and Planetary Institute Universities Space Research Association Johns Hopkins University, Applied Physics Laboratory Convener Kathleen Mandt John Hopkins University, Applied Physics Laboratory Science Organizing Committee Kathleen Mandt Johns Hopkins University, Applied Physics Laboratory William Farrell NASA Goddard Space Flight Center Elizabeth Fisher Brown University Andrew Jordan University of New Hampshire Rachel Klima Johns Hopkins University, Applied Physics Laboratory Paul Lucey University of Hawaii Lunar and Planetary Institute 3600 Bay Area Boulevard Houston TX 77058-1113 Abstracts for this meeting are available via the meeting website at https://www.hou.usra.edu/meetings/lunarvolatiles2018/ Abstracts can be cited as Author A. B. and Author C. D. (2018) Title of abstract. In Lunar Polar Volatiles, Abstract #XXXX. LPI Contribution No. 2087, Lunar and Planetary Institute, Houston. Guide to Sessions Tuesday, August 7, 2018 9:00 a.m. Bldg. 200, Room E-100 Lunar Polar Volatiles: Current Understanding, Recent Discoveries, and Future Exploration 10:45 a.m. Bldg. 200, Room E-100 Volatile Sources for the Lunar Poles: I 1:30 p.m. Bldg. 200, Room E-100 Volatile Sources for the Lunar Poles: II 3:00 p.m. Bldg. 200, Room E-100 Panel Discussion on Volatile Sources 4:00 p.m. Bldg. 200, Room E-100 Distribution Differences Between the Surface and Deeper Volatiles: I 5:00 p.m. Bldg. 200, Lobby Welcome Reception Wednesday, August 8, 2018 9:00 a.m. Bldg. 200, Room E-100 Distribution Differences Between the Surface and Deeper Volatiles: II 10:30 a.m. Bldg. 200, Room E-100 Panel Discussion on Distribution of Volatiles 1:00 p.m. Bldg. 200, Room E-100 Transport of Volatiles at the Poles and Processes that Influence Distribution: I 3:50 p.m. Bldg. 200, Room E-100 Panel Discussion on Transport and Processes: I 5:30 p.m. Bldg. 200, Room E-100 Poster Session: Lunar Polar Volatiles Workshop Thursday, August 9, 2018 9:00 a.m. Bldg. 200, Room E-100 Transport of Volatiles at the Poles and Processes that Influence Distribution: II 10:15 a.m. Bldg. 200, Room E-100 Panel Discussion on Transport and Processes: II 10:45 a.m. Bldg. 200, Room E-100 Composition of Lunar Polar Volatiles: It’s More Than Just Water! 11:45 a.m. Bldg. 200, Room E-100 Panel Discussion for Composition of Lunar Polar Volatiles: It’s More Than Just Water! 1:20 p.m. Bldg. 200, Room E-100 Future Steps 4:00 p.m. Bldg. 200, Room E-100 Panel Discussion on Future Steps Program Tuesday, August 7, 2018 LUNAR POLAR VOLATILES: CURRENT UNDERSTANDING, RECENT DISCOVERIES, AND FUTURE EXPLORATION 9:00 a.m. Bldg. 200, Room E-100 Chair: Kathleen Mandt 9:00 a.m. Mandt K. * Welcome and Logistics 9:15 a.m. Hayne P. O. * Lunar Polar Volatiles: Current Understanding, Recent Discoveries, and Future Exploration [#5017] Recent observations and models have provided new insights into the nature and origins of lunar polar volatiles. I will provide a summary of current understanding of lunar volatiles and possible future directions for addressing outstanding questions. 10:15 a.m. Coffee Break VOLATILE SOURCES FOR THE LUNAR POLES: I 10:45 a.m. Bldg. 200, Room E-100 Chair: David Blewett 10:45 a.m. Lucey P. G. * Hurley D. Farrell W. Petro N. E. Cable M. Dyar D. Orlando T. McCanta M. Fisher E. Hibbitts K. Prem P. Benna M. Hayne P. Green R. Pieters C. M. Mandt K. Horyani M. Haleakas J. Li S. The Lunar Volatile System in Space and Time: Supplies to the Lunar Poles [#5015] Volatile sources for the poles vary in space and time. Now, meteorites and solar wind dominate the inputs; in the past volcanic eruptions and impacts overwhelmed the current sources. Major gaps in understanding persist regarding all epochs. 11:05 a.m. Needham D. H. * Kring D. A. A Volcanic Source for Lunar Polar Volatiles [#5009] Ancient eruptions of lunar mare basalts released significant masses of volatiles around the Moon. These internally sourced volatiles may have migrated to the lunar poles, forming a substantial component of currently observed polar volatile deposits. 11:25 a.m. Tucker O. J. * Killen R. M. Saxena P. Johnson R. E. Prem P. Lifetime of a Transient Atmosphere Produced by Lunar Volcanism [#5039] We estimate the thermal escape lifetime of a volcanically produced early Moon atmosphere for comparison to the Needham and Kring (2017), Earth and Planet. Sci., study. 11:45 a.m. Orlando T. M. * Jones B. M. Alexandrov A. B. Hibbitts C. A. Dyar M. D. A Solar Wind Source of Water in the Polar Regions of the Moon? [#5008] We address formation of water via thermally activated recombinative desorption of hydroxyls in proton irradiated regolith. This temperature dependent process can lead to limited water build-up at the poles or in permanently shadowed regions. 12:05 p.m. Lunch Tuesday, August 7, 2018 VOLATILE SOURCES FOR THE LUNAR POLES: II 1:30 p.m. Bldg. 200, Room E-100 Chair: David Blewett 1:30 p.m. Mandt K. E. * Luspay-Kuti A. Comets and Meteorites as Sources of Lunar Polar Volatiles [#5041] Volatiles stored in the lunar polar region could provide a time-line of volatile delivery to the Moon. We will review composition tracers for comets and meteorites that can be used to evaluate the history of volatile delivery to the Moon. 1:50 p.m. Schorghofer N. * Transport in the Lunar Water Exosphere [#5004] A surface-bounded exosphere has a non-exponential vertical density distribution. Delivery of water to the polar cold traps is dramatically more efficient on the Moon than on Mercury and Ceres. Uncertainties lie with the surface interaction. 2:10 p.m. Taylor G. J. * Kring D. A. Needham D. H. The Lunar Interior as a Source of Polar Water [#5007] Water released from the lunar crust by moonquakes and impacts each account for between 100 and 10,000 kg of water per year, at least three orders of magnitude less than contributed by solar wind or impact of water-bearing projectiles. 2:30 p.m. Coffee Break PANEL DISCUSSION ON VOLATILE SOURCES 3:00 p.m. Bldg. 200, Room E-100 Moderator: Adrienn Luspay-Kuti Panel Members: Kathleen Mandt Jeff Taylor Debra Needham O. J. Tucker Tuesday, August 7, 2018 DISTRIBUTION DIFFERENCES BETWEEN THE SURFACE AND DEEPER VOLATILES: I 4:00 p.m. Bldg. 200, Room E-100 Chair: John Gruener 4:00 p.m. Siegler M. A. * Keane J. T. Paige D. A. Subsurface Ice Stability on the Moon [#5038] The Moon has about 26,000 km2 of surface area in the large shadowed regions near the poles where ice could be stable. However, over 240,000 km2 of area in the upper meter alone that could hide subsurface ice. Much of the lunar ice may be at depth. 4:20 p.m. Jordan A. P. * Wilson J. K. Schwadron N. A. Spence H. E. Petro N. E. A Framework to Determine the History of the Moon’s Polar Ice [#5003] We describe a framework for interpreting the large-scale distribution of water ice in the polar regions of the Moon, and we show how this framework can help constrain the history of the ice as a function of depth. 4:40 p.m. McClanahan T. P. * Mitrofanov I. G. Boynton W. V. Chin G. Livengood T. A. Sanin A. Litvak M. Parsons A. Hamara D. Harshman K. Starr R. Su J. J. Lunar Regolith Geochemistry Variation May Explain the Polar Wander Observations [#5012] We examine recently recalibrated Lunar Exploration Neutron Detector (LEND) polar observations and the observation of polar wander. Preliminary studies suggest that regolith geochemistry variation could explain the polar wander observation. Wednesday, August 8, 2018 DISTRIBUTION DIFFERENCES BETWEEN THE SURFACE AND DEEPER VOLATILES: II 9:00 a.m. Bldg. 200, Room E-100 Chair: Susan Klem 9:00 a.m. Fisher E. A. * Lucey P. G. Lemelin M. Greenhagen B. T. Siegler M. A. Mazarico E. Aharonson O. Williams J. Hayne P. O. Neumann G. A. Paige D. A. Smith D. E. Zuber M. T. Evidence for Surface Water Ice in the Lunar Polar Regions Using Reflectance Measurements from the Lunar Orbiter Laser Altimeter and Temperature Measurements from the Diviner Lunar Radiometer Experiment [#5011] We study LOLA derived normal albedo as a function of Diviner maximum temperature, to see if lunar permanently shadowed regions cold enough (<110K) to preserve surface water frost over geologic timescales show increased reflectance. 9:20 a.m. Li S. * Lucey P. G. Milliken R. E. Hayne P. O. Fisher E. Williams J. P. Hurley D. Elphic R. C. Direct Detections of Surface Exposed Water Ice in the Lunar Polar Regions [#5010] IR absorptions of ice near 1.3, 1.5, and 2.0-µm were detected using the M3 data near the lunar polar regions, which is the first direct evidence for surface exposed water ice on the Moon. The distribution and formation of ice are also discussed. 9:40 a.m. Raut U. * Karnes P. L. Retherford K. D. Czajka E. Poston M. J. Davis M. W. Liu Y. Patrick E. L. Gladstone G. R. Greathouse T. K. Hendrix A. R. Mokashi P. Investigating Far-ultraviolet hydration signatures in the Southwest Ultraviolet Reflectance Chamber (SwURC) in support of LRO-LAMP observations [#5037] We will present results from our laboratory investigations on far-ultraviolet reflectance measurements of dry and water vapor-exposed Apollo soils made in support of LRO-LAMP observations. 10:00 a.m. Coffee Break PANEL DISCUSSION ON DISTRIBUTION OF VOLATILES 10:30 a.m.