Brief Bio

Noah Petro first became interested in Geology as a student at Fox Lane High School in Bedford, NY. It was while he was a student at Bates College that he was introduced to the field of planetary geology. Following his PhD work at Brown University he came to NASA Goddard as a NASA Post-Doc.

Noah's reasearch focuses on the evolution of the lunar crust, specifically the role of impact cratering in distributing material across the lunar surface. He uses remotely sensed data from multiple lunar missions, as well as data and samples collected by Apollo astronauts, to create a comprehensive picture of the Moons surface.

He currently serves as a mentor to Dr. Sarah Valencia, Dr. Jordan Kendall, Dr. Daniel Moriarty, and Dr. Caitlin Ahrens.

Publications

Refereed

Shearer, C. K., D. P. Moriarty, S. B. Simon, N. Petro, and J. J. Papike. 2023. "Where Is the Lunar Mantle and Deep Crust at Crisium? A Perspective From the Luna 20 Samples." Journal of Geophysical Research: Planets 128 (5): [10.1029/2022je007409]

Moriarty, D. P., S. Simon, C. Shearer, et al. S. Haggerty, N. Petro, and S. Li. 2023. "Orbital Characterization of the Composition and Distribution of Spinels across the Crisium Region: Insight from Luna 20 Samples." Journal of Geophysical Research: Planets [10.1029/2022je007482]

Mazarico, E., M. K. Barker, A. M. Jagge, et al. A. W. Britton, S. J. Lawrence, N. E. Petro (he/him), and J. E. Bleacher. 2022. "Sunlit Pathways between South Pole Sites of Interest for Lunar Exploration." Acta Astronautica (In Press) [Full Text (Link)] [10.1016/j.actaastro.2022.12.023]

Simon, S. B., C. K. Shearer, S. E. Haggerty, et al. D. P. Moriarty, N. Petro, J. J. Papike, and Z. Vaci. 2022. "Multiple Shallow Crustal Origins for Spinel‐Bearing Lithologies on the Moon: A Perspective From the Luna 20 Mission." Journal of Geophysical Research: Planets 127 (11): [10.1029/2022je007249]

Lucey, P. G., N. Petro, D. M. Hurley, et al. W. M. Farrell, P. Prem, E. S. Costello, M. L. Cable, M. K. Barker, M. Benna, M. D. Dyar, E. A. Fisher, R. O. Green, P. O. Hayne, K. Hibbitts, C. Honniball, S. Li, E. Malaret, K. Mandt, E. Mazarico, M. McCanta, C. Pieters, X. Sun, D. Thompson, and T. Orlando. 2021. "Volatile interactions with the lunar surface." Geochemistry (In Press) 125858 [10.1016/j.chemer.2021.125858]

Moriarty, D. P., N. Dygert, S. N. Valencia, R. N. Watkins, and N. E. Petro. 2021. "The search for lunar mantle rocks exposed on the surface of the Moon." Nature Communications 12 (1): 4659 [10.1038/s41467-021-24626-3]

Cohen, B. A., K. E. Young, N. E. Zellner, et al. K. Zacny, R. A. Yingst, R. N. Watkins, R. Warwick, S. N. Valencia, T. D. Swindle, S. J. Robbins, N. E. Petro, A. Nicoletti, D. P. Moriarty, R. Lynch, S. J. Indyk, J. Gross, J. A. Grier, J. A. Grant, A. Ginyard, C. I. Fassett, K. A. Farley, B. J. Farcy, B. L. Ehlmann, M. D. Dyar, G. Daelemans, N. M. Curran, C. H. van der Bogert, R. D. Arevalo, and F. Scott Anderson. 2021. "In Situ Geochronology for the Next Decade: Mission Designs for the Moon, Mars, and Vesta." The Planetary Science Journal 2 (4): 145 [10.3847/psj/abedbf]

Ahrens, C. J., D. A. Paige, T. M. Eubanks, et al. W. P. Blase, K. E. Mesick, W. Zimmerman, N. Petro, P. O. Hayne, and S. Price. 2021. "Small Penetrator Instrument Concept for the Advancement of Lunar Surface Science." The Planetary Science Journal 2 (1): 38 [10.3847/psj/abda4f]

Moriarty, D. P., R. N. Watkins, S. N. Valencia, et al. J. D. Kendall, A. J. Evans, and N. E. Petro. 2020. "Evidence for a Stratified Upper Mantle Preserved within the South Pole – Aitken Basin." Journal of Geophysical Research - Planets (In Press) [10.1029/2020JE006589]

Bretzfelder, J. M., R. L. Klima, B. T. Greenhagen, et al. D. L. Buczkowski, N. E. Petro, and M. Day. 2020. "Identification of Potential Mantle Rocks Around the Lunar Imbrium Basin." Geophysical Research Letters (In Press) 47 (22): [10.1029/2020gl090334]

Moriarty, D. P., D. P. Moriarty, S. N. Valencia, R. N. Watkins, and N. E. Petro. 2020. "Illuminating the Lunar Mantle: A Brief Assessment of the State of Current Knowledge and Critical Exploration Targets for Advancing our Understanding." Nature Communications (Submitted)

Saxena, P., R. M. Killen, V. Airapetian, et al. N. E. Petro, N. M. Curran, and A. M. Mandell. 2019. "Was the Sun a Slow Rotator? Sodium and Potassium Constraints from the Lunar Regolith." The Astrophysical Journal 876 (1): L16 [10.3847/2041-8213/ab18fb]

Schwadron, N., J. Wilson, A. Jordan, et al. M. Looper, C. Zeitlin, L. Townsend, H. Spence, J. Legere, P. Bloser, W. Farrell, D. Hurley, N. Petro, T. Stubbs, and C. Pieters. 2018. "Using proton radiation from the moon to search for diurnal variation of regolith hydrogenation." Planetary and Space Science 162 113-132 [10.1016/j.pss.2017.09.012]

Starr, R. D., M. L. Litvak, N. E. Petro, et al. I. G. Mitrofanov, W. V. Boynton, G. Chin, T. A. Livengood, T. P. McClanahan, A. B. Sanin, R. Z. Sagdeev, and J. J. Su. 2018. "Crater age and hydrogen content in lunar regolith from LEND neutron data." Planetary and Space Science 162 105–112 [10.1016/j.pss.2017.08.001]

Henning, W. G., J. P. Renaud, A. M. Mandell, et al. P. Saxena, T. A. Hurford, S. Matsumura, L. S. Glaze, T. A. Livengood, V. Airapetian, E. Asphaug, J. K. Teske, E. Schwieterman, M. Efroimsky, V. V. Makarov, C. T. Berghea, J. Bleacher, A. Rushby, Y. Lee, W. Kuang, R. Barnes, C. Dong, P. Driscoll, S. D. Domagal-Goldman, N. C. Schmerr, A. D. Del Genio, A. G. Jensen, L. Kaltenegger, L. Elkins-Tanton, E. L. Shock, L. E. Sohl, E. Quintana, L. Schaefer, T. S. Barclay, Y. Fujii, K. Hamano, N. E. Petro, E. D. Lopez, and D. D. Sasselov. 2018. "Exoplanet Science Priorities from the Perspective of Internal and Surface Processes for Silicate and Ice Dominated Worlds." National Academy of Sciences 2018 Exoplanet Science Strategy White Paper

Schwadron, N. A., F. Rahmanifard, J. Wilson, et al. A. P. Jordan, H. E. Spence, C. J. Joyce, J. B. Blake, A. W. Case, W. de Wet, W. M. Farrell, J. C. Kasper, M. D. Looper, N. Lugaz, J. E. Mazur, L. Mays, J. Niehof, N. Petro, C. W. Smith, L. W. Townsend, R. Winslow, and C. Zeitlin. 2018. "Update on the Worsening Particle Radiation Environment Observed by CRaTER and Implications for Future Human Deep-Space Exploration." Space Weather 16 (3): 289-303 [10.1002/2017sw001803]

Schmitt, H., N. Petro, R. Wells, et al. M. Robinson, B. Weiss, and C. Mercer. 2017. "Revisiting the Field Geology of Taurus-Littrow." Icarus [10.1016/j.icarus.2016.11.042]

Saxena, P., L. Elkins-Tanton, N. Petro, and A. Mandell. 2017. "A model of the primordial lunar atmosphere." Earth and Planetary Science Letters 474 198-205 [10.1016/j.epsl.2017.06.031]

Klima, R. L., and N. E. Petro. 2017. "Remotely distinguishing and mapping endogenic water on the Moon." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 375 (2094): 20150391 [10.1098/rsta.2015.0391]

Petro, N. E., J. W. Keller, and L. R. Gaddis. 2017. "Editorial Introduction: Lunar Reconnaissance Orbiter, part II." Icarus 283 1 [10.1016/j.icarus.2016.11.018]

Denevi, B. W., A. W. Beck, E. I. Coman, et al. B. J. Thomson, E. Ammannito, D. T. Blewett, J. M. Sunshine, M. C. De Sanctis, J.-Y. Li, S. Marchi, D. W. Mittlefehldt, N. E. Petro, C. A. Raymond, and C. T. Russell. 2016. "Global variations in regolith properties on asteroid Vesta from Dawn's low-altitude mapping orbit." Meteoritics & Planetary Science 51 (12): 2366-2386 [10.1111/maps.12729]

Collier, M. R., R. R. Vondrak, R. P. Hoyt, et al. M. A. Mesarch, W. M. Farrell, J. W. Keller, P. E. Clark, N. E. Petro, and K.-J. Hwang. 2016. "Tethered lunar subsatellites for multipoint and low altitude measurements." Acta Astronautica 128 464-472 [10.1016/j.actaastro.2016.07.047]

Keller, J., N. Petro, and R. Vondrak. 2016. "The Lunar Reconnaissance Orbiter Mission – Six years of science and exploration at the Moon." Icarus 273 2-24 [10.1016/j.icarus.2015.11.024]

Greenhagen, B. T., C. D. Neish, J.-P. Williams, et al. J. T. Cahill, R. R. Ghent, P. O. Hayne, S. J. Lawrence, N. E. Petro, and J. L. Bandfield. 2016. "Origin of the anomalously rocky appearance of Tsiolkovskiy crater." Icarus [10.1016/j.icarus.2016.02.041]

Schwadron, N., J. Wilson, M. Looper, et al. A. Jordan, H. Spence, J. Blake, A. Case, Y. Iwata, J. Kasper, W. Farrell, D. Lawrence, G. Livadiotis, J. Mazur, N. Petro, C. Pieters, M. Robinson, S. Smith, L. Townsend, and C. Zeitlin. 2015. "Signatures of volatiles in the lunar proton albedo." Icarus [10.1016/j.icarus.2015.12.003]

Schwadron, N., J. Blake, and N. E. Petro. 2014. "Does the worsening galactic cosmic radiation environment observed by CRaTER preclude future manned deep space exploration?" Space Weather 11 [10.1002/2014SW001084]

Shearer, C., S. Elardo, N. E. Petro, L. Borg, and F. McCubbin. 2014. "Origin of the lunar highlands Mg-suite: An integrated petrology, geochemistry, chronology, and remote sensing perspective." 100 294–325 [Full Text (Link)] [10.2138/am-2015-4817]

Isaacson, P., N. E. Petro, and M. Moon Mineralogy. 2013. "Development, importance, and effect of a ground truth correction for the Moon Mineralogy Mapper reflectance data set." Journal of Geophysical Research: Planets 118 (3): 369-381 [Full Text (Link)] [10.1002/jgre.20048]

Denevi, B. W., D. T. Blewettt, D. L. Buczkowski, et al. F. Capaccioni, M. T. Capria, M. C. De Sanctis, W. B. Garry, R. W. Gaskell, L. Le Corre, J.-Y. Li, S. Marchi, T. J. McCoy, A. Nathues, D. P. O'Brien, N. E. Petro, C. M. Pieters, F. Preusker, C. A. Raymond, V. Reddy, C. T. Russell, P. Schenk, J. E. Scully, J. M. Sunshine, F. Tosi, D. A. Williams, D. Wyrick, and Dawn Science Team. 2012. "Pitted Terrain on Vesta and Implications for the Presence of Volatiles." Science 338 (6104): 246-249 [DOI:10.1126/science.1225374]

Clark, P. E., J. E. Bleacher, N. E. Petro, and S. C. Mest. 2011. "Plan for a human expedition to Marius Hills and its implications for viable surface exploration architecture." In Garry and Bleacher (eds), Analogs for Planetary Exploration, Geological Society of America Special Paper 483 519-532 [doi:10.1130/2011.2483(31)]

Clark, P. E., S. C. Mest, J. E. Bleacher, and N. E. Petro. 2011. "Advanced regional-scale scenarios for lunar surface exploration ." In Garry and Bleacher (eds), Analogs for Planetary Exploration, Geological Society of America Special Paper 483 547-567 [doi:10.1130/2011.2483(33)]

Clark, P., S. C. Mest, J. Bleacher, and N. E. Petro. 2011. "Advanced Regional-Scale Scenarios for Lunar Surface Exploration, Analogs for Planetary Exploration." Geological Society of America Special Papers 483 547 [10.1130/2011.2483(33)]

Pieters, C., S. Besse, J. Boardman, et al. B. Buratti, L. Cheek, R. Clark, J. Combe, D. Dhingra, J. Goswami, R. Green, J. Head, P. Isaacson, R. Klima, G. Kramer, S. Lundeen, E. Malaret, T. McCord, J. Mustard, J. Nettles, N. Petro, C. Runyon, M. Staid, J. Sunshine, L. Taylor, K. Thaisen, S. Tompkins, and J. Whitten. 2011. "Mg-spinel lithology: A new rock type on the lunar farside." Journal of Geophysical Research 116 -14 [10.1029/2010je003727]

Klima, R., C. Pieters, J. Boardman, et al. R. Green, J. Head, P. Isaacson, J. Mustard, J. Nettles, N. Petro, M. Staid, J. Sunshine, and L. Taylor. 2011. "New insights into lunar petrology: Distribution and composition of prominent low-Ca pyroxene exposures as observed by the Moon Mineralogy Mapper (M3)." Journal of Geophysical Research 116 -13 [10.1029/2010je003719]

Isaacson, P., C. Pieters, S. Besse, et al. R. Clark, J. Head, R. Klima, J. Mustard, N. E. Petro, M. Staid, J. Sunshine, L. Taylor, K. Thaisen, and S. Tompkins. 2011. "Remote compositional analysis of lunar olivine-rich lithologies with Moon Mineralogy Mapper (M3) spectra." Journal of Geophysical Research 116 -17 [10.1029/2010je003731]

Thaisen, K., J. Head, L. Taylor, et al. G. Kramer, P. Isaacson, J. Nettles, N. Petro, and C. Pieters. 2011. "Geology of the Moscoviense Basin." Journal of Geophysical Research 116 -14 [10.1029/2010je003732]

Petro, N., S. Mest, and R. nd Teich. 2011. "Geomorphic terrains and evidence for ancient volcanism within northeastern South PoleAitken basin." Recent Advances and Current Research Issues in Lunar Stratigraphy: Geological Society of America Special Paper 477 10.1130/2011.2477 (06):

Cheek, L. C., C. M. Pieters, J. W. Boardman, et al. R. N. Clark, J. P. Combe, J. W. Head, P. J. Isaacson, T. B. McCord, D. Moriarty, J. W. Nettles, N. E. Petro, J. M. Sunshine, and L. A. Taylor. 2011. "Goldschmidt crater and the Moon's north polar region: Results from the Moon Mineralogy Mapper (M3)." Journal of Geophysical Research 116 [Full Text (Link)] [10.1029/2010JE003702]

Pieters, C., J. Boardman, B. Buratti, et al. A. Chatterjee, R. Clark, T. Glavich, R. Green, J. Head, P. Isaccson, E. Malaret, T. McCord, J. Mustard, N. E. Petro, C. Runyon, M. Staid, J. Sunshine, L. Taylor, S. Tompkins, P. Varanasi, and M. White. 2009. "The Moon Mineralogy Mapper (M-3) on Chandrayaan-1 ." Current Science 96 (4): 500-505

Prabhat, M. R., A. Forsberg, G. Morgan, et al. N. Petro, J. Levy, and J. Head. 2006. "Virtual Field Trip to Mars: Experiences with a Virtual Reality Lab for Undergraduate Students." Lunar and Planetary Science Conference 37 1319

Petro, N., and C. Pieters. 2006. "The Effects of Basin Formation on the Lunar Geochemical Terranes." Lunar and Planetary Science Conference 37 1868

Petro, N., and C. Pieters. 2006. "The Lunar-wide Effects of Basin Formation on the Lunar Crust." Meteoritics and Planetary Science 43 (9): 9 [ 10.1111/j.1945-5100.2008.tb01025.x]

Petro, N., and C. Pieters. 2006. "Modeling the provenance of the Apollo 16 regolith." Journal of Geophysical Research Planets 111 E09005 [ 10.1029/2005JE002559]

Calvin, C., A. C. Rager, T. Balint, et al. D. Santiago, J. C. Anderson, T. Cassidy, D. Chavez-Clemente, B. Corbett, H. Hammerstein, T. Hanley, A. Letcher, E. McGowan, D. McMenamin, N. Murphy, M. Obland, J. Parker, T. Perron, N. E. Petro, M. Pulupa, R. Schofield, and H. Sizemore. 2005. "Endurance: The rewards and challenges of landing a spacecraft on Europa." AGU Fall Meeting Abstracts 11 0113

Petro, N., and C. Pieters. 2005. "The Lunar wide Effects of the Formation of Basins on the Megaregolith." Lunar and Planetary Science Conference 36 1209

Petro, N., and C. Pieters. 2004. "Comparison of the Geologic Setting of the South Pole-Aitken Basin Interior with Apollo 16: Implications for Regolith Components." In Lunar and Planetary Science 35 pp 1345

Petro, N. E., and C. Pieters. 2004. "Surviving the heavy bombardment: Ancient material at the surface of South Pole-Aitken Basin." Journal of Geophysical Research Planets 109 (E6): E06004 [10.1029/2003JE002182]

Petro, N., and C. Pieters. 2003. "How Much Melt Breccia Can be Found in South Pole-Aitken Basin?" In Lunar and Planetary Science Conference 34 1427

Gaddis, L. R., M. I. Staid, J. Tyburczy, B. Hawke, and N. Petro. 2003. "Compositional analyses of lunar pyroclastic deposits." Icarus 161 262-280 [ 10.1016/S0019-1035(02)00036-2]

Petro, N., and C. Pieters. 2002. "Reconstructing the Stratigraphy of the Ancient South Pole-Aitken Basin Interior." In The Moon Beyond 2002: Next Steps in Lunar Science and Exploration p. 47

Petro, N., and C. Pieters. 2002. "The Size and Location of the Transient Crater of the South Pole-Aitken Basin." In Lunar and Planetary Science Conference 32 1848

Petro, N., L. Gaddis, and M. Staid. 2001. "Analysis of the Oppenheimer Pyroclastic Deposits Using Clementine UVVIS Data." In Lunar and Planetary Science Conference 31 1953

Gaddis, L., M. Staid, and N. Petro. 2001. "Compositions of Lunar Pyroclastic Deposits." In Lunar and Planetary Science Conference 32 1372

Non-Refereed

Ahrens, C., and N. E. Petro (he/him). 2022. "Mapping Thermal Flux Boundaries Surrounding Permanently Shadowed Regions (PSRs) at the Lunar South Pole." Lunar Polar Volatiles Conference, LPI id.5008

Ahrens, C., and N. E. Petro (he/him). 2022. "Estimating the Rate of Growth or Shrinkage of the Amundsen Crater PSR Area." 53rd Lunar and Planetary Science Conference id. 2339

Glotch, T., L. Carter, P. Clark, et al. B. Denevi, B. Greenhagen, W. Patterson, N. Petro, K. Retherford, S. Valencia, R. Watkins, J. Cahill, K. D. Hanna, C. Elder, H. Hiesinger, G. Kramer, T. Livengood, H. Meyer, L. R. Ostrach, M. Poston, M. Shusterman, M. Siegler, E. Speyerer, A. Stickle, C. V. Bogert, D. Moriarty, and L. R. Gaddis. 2021. "A Next Generation Lunar Orbiter Mission." Vol. 53, Issue 4 (Planetary/Astrobiology Decadal Survey Whitepapers) 53 (4): e-id. 330 [10.3847/25c2cfeb.8f28f012]

Ahrens, C., M. E. Banks, and N. E. Petro. 2021. "The Spatial Relationship of Graben and Pit Craters at Rimae Daniell and the Implications of Scarp Formation." 52nd Lunar and Planetary Science Conference, held virtually, 15-19 March, 2021. LPI Contribution No. 2548, id.1481

Ahrens, C., N. E. Petro, and S. Li. 2021. "Preliminary Observations on the Relationship Between Fe-Signatures and PSR Locations at the Lunar South Pole." 52nd Lunar and Planetary Science Conference, held virtually, 15-19 March, 2021. LPI Contribution No. 2548, id.1478

Ahrens, C., N. E. Petro, and M. Siegler. 2020. "Preliminary Surface Thermal Flux Calculations Using LRO Diviner in Lunar Permanently Shadowed Craters." Lunar and Planetary Science Conference 51 1949

Saxena, P., R. M. Killen, V. Airapetian, et al. N. E. Petro, N. M. Curran, and A. M. Mandell. 2019. "The Sun was likely a Slow Rotator: Lunar Geochemical Constraints." LPI

Petro, N., J. Keller, B. Cohen, and T. McClanahan. 2019. "Ten Years of the Lunar Reconnaissance Orbiter (LRO): Advancing Lunar Science and Context for Future Lunar Exploration." Proceedings of the 50th Lunar and Planetary Science Conference, The Woodlands, Texas, U.S.A., March 18-22, 2019 Paper # 2780 [Full Text (Link)]

Wasser, M. L., A. J. Jones, N. E. Petro, and L. Bleacher. 2019. "Total Eclipse of the Ballpark: NASA's Lunar Reconnaissance Orbiter Team's Partnership with Minor League Baseball." Celebrating the 2017 Great American Eclipse: Lessons Learned from the Path of Totality 516 321 - 330

Saxena, P., R. Killen, V. Airapetian, et al. N. Petro, N. Curran, and A. Mandell. 2019. "The Sun was likely a Slow Rotator: Lunar Geochemical Constraints." Lunar and Planetary Science Conference 50

Cohen, B., N. Petro, S. Lawrence, et al. S. Clegg, B. Denevi, M. Dyar, S. Elardo, D. Grinspoon, H. Hiesinger, Y. Liu, and D. Moriarty. 2018. "Curie: Constraining Solar System Bombardment Using In Situ Radiometric Dating." Lunar and Planetary Science Conference 49

Keller, J. W., L. Gaddis, N. Petro, and O. Aharonson. 2017. "Preface: The Lunar Reconnaissance Orbiter." Icarus 298 1 [10.1016/j.icarus.2017.09.001]

Keller, J. W., L. Gaddis, and N. Petro. 2017. "Introduction: The Lunar Reconnaissance Orbiter-Part III." Icarus 298 1-1 [10.1016/j.icarus.2017.09.001]

Thronson, H. A., A. Valinia, J. E. Bleacher, et al. J. L. Eigenbrode, J. B. Garvin, and N. E. Petro. 2014. "Low-Latency Science Exploration of Planetary Bodies: How ISS might be used as part of a Low-Latency Analog Campaign for Human Exploration." American Institute of Aeronautics and Astronautics (AIAA) [Full Text (Link)]

Farrell, W. M., J. E. Bleacher, T. J. Ames, et al. L. M. Carter, C. Y. Cheung, M. R. Collier, J. F. Cooper, R. L. Hudson, T. L. Jackson, J. W. Keller, R. M. Killen, M. M. Kuznetsova, M. J. Loeffler, R. J. MacDowall, A. M. Parsons, N. E. Petro, A. A. Pulkkinen, Y. Zheng, and M. I. Zimmerman. 2013. "'Where to Hide?': A Tele-Robotic Application for HEOMD's Earth-Moon L2 Mission." Lunar and Planetary Institute Science Conference Abstracts 44 2514

Moriarty, D., C. Pieters, N. Petro, and P. Isaacson. 2012. "Compositional heterogeneity within lunar central peaks." Lunar and Planetary Science Conference 43

Pieters, C., P. Isaacson, L. Taylor, et al. J. Head, D. Dhingra, R. Klima, N. Petro, D. Moriarty, R. Green, and J. Boardman. 2011. "Compositional structure of the lower lunar crust: Initial constraints from basin mineralogy." Lunar and Planetary Science Conference 42 2173

Moriarty, D., C. Pieters, J. Nettles, et al. P. Isaacson, L. Cheek, J. Head, S. Tompkins, and N. Petro. 2011. "Finsen and Alder: A compositional study of lunar central peak craters in the South Pole-Aitken basin." Lunar and Planetary Science Conference 42 2564