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Chabot NL, Peplowski PN, Ernst CM, Nair H, Lucks M, Steele RJ, Lawrence DJ. MEGANE investigations of Phobos and the Small Body Mapping Tool. EARTH, PLANETS, AND SPACE : EPS 2021; 73:217. [PMID: 34970072 PMCID: PMC8666434 DOI: 10.1186/s40623-021-01509-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 08/25/2021] [Indexed: 06/14/2023]
Abstract
The MEGANE instrument onboard the MMX mission will acquire gamma-ray and neutron spectroscopy data of Phobos to determine the elemental composition of the martian moon and provide key constraints on its origin. To produce accurate compositional results, the irregular shape of Phobos and its proximity to Mars must be taken into account during the analysis of MEGANE data. The MEGANE team is adapting the Small Body Mapping Tool (SBMT) to handle gamma-ray and neutron spectroscopy investigations, building on the demonstrated record of success of the SBMT being applied to scientific investigations on other spacecraft missions of irregularly shaped bodies. This is the first application of the SBMT to a gamma-ray and neutron spectroscopy dataset, and the native, three-dimensional foundation of the SBMT is well suited to MEGANE's needs. In addition, the SBMT will enable comparisons between the MEGANE datasets and other datasets of the martian moons, including data from previous spacecraft missions and MMX's multi-instrument suite.
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Affiliation(s)
- Nancy L. Chabot
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Rd, Laurel, MD 20723 USA
| | - Patrick N. Peplowski
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Rd, Laurel, MD 20723 USA
| | - Carolyn M. Ernst
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Rd, Laurel, MD 20723 USA
| | - Hari Nair
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Rd, Laurel, MD 20723 USA
| | - Michael Lucks
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Rd, Laurel, MD 20723 USA
| | - R. Josh Steele
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Rd, Laurel, MD 20723 USA
| | - David J. Lawrence
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Rd, Laurel, MD 20723 USA
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2
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Deutsch AN, Head JW, Neumann GA. Age constraints of Mercury's polar deposits suggest recent delivery of ice. EARTH AND PLANETARY SCIENCE LETTERS 2019; 520:26-33. [PMID: 32454531 PMCID: PMC7243170 DOI: 10.1016/j.epsl.2019.05.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Surface ice at the poles of Mercury appears as several-m-thick deposits that are composed of nearly pure water. We provide new age estimates of Mercury's polar deposits from combined analyses of Poisson statistics and direct observations of crater densities within permanently shadowed, radar-bright regions imaged by the MESSENGER spacecraft. These age estimates suggest that ice was delivered to Mercury within the last ~150 Myr. A single, recent impactor is one possible delivery mechanism that is consistent with our new age constraints, as well as the observed distinct reflectance boundaries of the polar deposits and the relative purity of the ice, as suggested by the Earth-based radar observations. In contrast to ice on Mercury, observations of the lunar poles are suggestive of a highly patchy distribution of surface frost. The patchiness of lunar polar deposits is consistent with long exposure times to the space weathering environment. Given enough time, the polar deposits on Mercury may age into a more heterogeneous spatial distribution, similar to that on the Moon.
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Affiliation(s)
- Ariel N. Deutsch
- Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI 02912, USA
| | - James W. Head
- Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI 02912, USA
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Mitrofanov IG, Litvak ML, Nikiforov SY, Jun I, Bobrovnitsky YI, Golovin DV, Grebennikov AS, Fedosov FS, Kozyrev AS, Lisov DI, Malakhov AV, Mokrousov MI, Sanin AB, Shvetsov VN, Timoshenko GN, Tomilina TM, Tret'yakov VI, Vostrukhin AA. The ADRON-RM Instrument Onboard the ExoMars Rover. ASTROBIOLOGY 2017; 17:585-594. [PMID: 28731818 DOI: 10.1089/ast.2016.1566] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
This overview presents the physical principles, design, measurement capabilities, and summary of planned operations of the autonomous detector of radiation of neutrons onboard rover at Mars (ADRON-RM) on the surface of Mars. ADRON-RM is a Russian project selected for the joint European Space Agency-Roscosmos ExoMars 2020 landing mission. A compact passive neutron spectrometer, ADRON-RM, was designed to study the abundance and distribution of water and neutron absorption elements (such as Cl, Fe, and others) in the martian subsurface along the path of the ExoMars rover. Key Words: Mars exploration-Surface-Neutron Spectroscopy-Water. Astrobiology 17, 585-594.
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Affiliation(s)
- I G Mitrofanov
- 1 Institute for Space Research , Russian Academy of Sciences, Moscow, Russia
| | - M L Litvak
- 1 Institute for Space Research , Russian Academy of Sciences, Moscow, Russia
| | - S Y Nikiforov
- 1 Institute for Space Research , Russian Academy of Sciences, Moscow, Russia
| | - I Jun
- 2 Jet Propulsion Laboratory, California Institute of Technology , Pasadena, California
| | - Y I Bobrovnitsky
- 3 A.A. Blagonravov Institute of Mechanical Engineering , Russian Academy of Sciences, Moscow, Russia
| | - D V Golovin
- 1 Institute for Space Research , Russian Academy of Sciences, Moscow, Russia
| | - A S Grebennikov
- 3 A.A. Blagonravov Institute of Mechanical Engineering , Russian Academy of Sciences, Moscow, Russia
| | - F S Fedosov
- 1 Institute for Space Research , Russian Academy of Sciences, Moscow, Russia
| | - A S Kozyrev
- 1 Institute for Space Research , Russian Academy of Sciences, Moscow, Russia
| | - D I Lisov
- 1 Institute for Space Research , Russian Academy of Sciences, Moscow, Russia
| | - A V Malakhov
- 1 Institute for Space Research , Russian Academy of Sciences, Moscow, Russia
| | - M I Mokrousov
- 1 Institute for Space Research , Russian Academy of Sciences, Moscow, Russia
| | - A B Sanin
- 1 Institute for Space Research , Russian Academy of Sciences, Moscow, Russia
| | - V N Shvetsov
- 4 Joint Institute of Nuclear Research , Dubna, Russia
| | | | - T M Tomilina
- 3 A.A. Blagonravov Institute of Mechanical Engineering , Russian Academy of Sciences, Moscow, Russia
| | - V I Tret'yakov
- 1 Institute for Space Research , Russian Academy of Sciences, Moscow, Russia
| | - A A Vostrukhin
- 1 Institute for Space Research , Russian Academy of Sciences, Moscow, Russia
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Peplowski PN, Beck AW, Lawrence DJ. Geochemistry of the lunar highlands as revealed by measurements of thermal neutrons. JOURNAL OF GEOPHYSICAL RESEARCH. PLANETS 2016; 121:388-401. [PMID: 27830110 PMCID: PMC5076490 DOI: 10.1002/2015je004950] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 02/26/2016] [Accepted: 02/29/2016] [Indexed: 06/02/2023]
Abstract
Thermal neutron emissions from the lunar surface provide a direct measure of bulk elemental composition that can be used to constrain the chemical properties of near-surface (depth <1 m) lunar materials. We present a new calibration of the Lunar Prospector thermal neutron map, providing a direct link between measured count rates and bulk elemental composition. The data are used to examine the chemical and mineralogical composition of the lunar surface, with an emphasis on constraining the plagioclase concentration across the highlands. We observe that the regions of lowest neutron absorption, which correspond to estimated plagioclase concentrations of >85%, are generally associated with large impact basins and are colocated with clusters of nearly pure plagioclase identified with spectral reflectance data.
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Affiliation(s)
| | - Andrew W Beck
- The Johns Hopkins University Applied Physics Laboratory Laurel Maryland USA
| | - David J Lawrence
- The Johns Hopkins University Applied Physics Laboratory Laurel Maryland USA
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Lawrence DJ, Feldman WC, Peplowski PN, Solomon SC. The 4 June 2011 neutron event at Mercury: A defense of the solar origin hypothesis. JOURNAL OF GEOPHYSICAL RESEARCH. SPACE PHYSICS 2015; 120:5284-5289. [PMID: 26937331 PMCID: PMC4758620 DOI: 10.1002/2015ja021069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 06/01/2015] [Accepted: 06/03/2015] [Indexed: 06/05/2023]
Abstract
We address claim that neutrons from a 4 June 2011 event at Mercury are nonsolarThe claim is based on an erroneous assumption about instrument singles countsThe best interpretation of the neutron event is that the neutrons have a solar origin.
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Affiliation(s)
- David J Lawrence
- The Johns Hopkins University Applied Physics Laboratory Laurel Maryland USA
| | | | | | - Sean C Solomon
- Department of Terrestrial Magnetism Carnegie Institution of Washington Washington District of Columbia USA; Lamont-Doherty Earth Observatory Columbia University Palisades New York USA
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Lawrence DJ, Peplowski PN, Prettyman TH, Feldman WC, Bazell D, Mittlefehldt DW, Reedy RC, Yamashita N. Constraints on Vesta's elemental composition: Fast neutron measurements by Dawn's gamma ray and neutron detector. METEORITICS & PLANETARY SCIENCE 2013; 48:2271-2288. [PMID: 26074718 PMCID: PMC4461122 DOI: 10.1111/maps.12187] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 07/11/2013] [Indexed: 06/04/2023]
Abstract
Surface composition information from Vesta is reported using fast neutron data collected by the gamma ray and neutron detector on the Dawn spacecraft. After correcting for variations due to hydrogen, fast neutrons show a compositional dynamic range and spatial variability that is consistent with variations in average atomic mass from howardite, eucrite, and diogenite (HED) meteorites. These data provide additional compositional evidence that Vesta is the parent body to HED meteorites. A subset of fast neutron data having lower statistical precision show spatial variations that are consistent with a 400 ppm variability in hydrogen concentrations across Vesta and supports the idea that Vesta's hydrogen is due to long-term delivery of carbonaceous chondrite material.
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Affiliation(s)
- David J Lawrence
- The Johns Hopkins University Applied Physics LaboratoryLaurel, Maryland, USA
| | - Patrick N Peplowski
- The Johns Hopkins University Applied Physics LaboratoryLaurel, Maryland, USA
| | | | | | - David Bazell
- The Johns Hopkins University Applied Physics LaboratoryLaurel, Maryland, USA
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Boynton WV, Droege GF, Mitrofanov IG, McClanahan TP, Sanin AB, Litvak ML, Schaffner M, Chin G, Evans LG, Garvin JB, Harshman K, Malakhov A, Milikh G, Sagdeev R, Starr R. High spatial resolution studies of epithermal neutron emission from the lunar poles: Constraints on hydrogen mobility. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011je003979] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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8
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Lawrence DJ, Feldman WC, Goldsten JO, Maurice S, Peplowski PN, Anderson BJ, Bazell D, McNutt RL, Nittler LR, Prettyman TH, Rodgers DJ, Solomon SC, Weider SZ. Evidence for water ice near Mercury's north pole from MESSENGER Neutron Spectrometer measurements. Science 2012. [PMID: 23196909 DOI: 10.1126/science.1229953] [Citation(s) in RCA: 149] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Measurements by the Neutron Spectrometer on the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft show decreases in the flux of epithermal and fast neutrons from Mercury's north polar region that are consistent with the presence of water ice in permanently shadowed regions. The neutron data indicate that Mercury's radar-bright polar deposits contain, on average, a hydrogen-rich layer more than tens of centimeters thick beneath a surficial layer 10 to 30 cm thick that is less rich in hydrogen. Combined neutron and radar data are best matched if the buried layer consists of nearly pure water ice. The upper layer contains less than 25 weight % water-equivalent hydrogen. The total mass of water at Mercury's poles is inferred to be 2 × 10(16) to 10(18) grams and is consistent with delivery by comets or volatile-rich asteroids.
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Affiliation(s)
- David J Lawrence
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA.
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Miller RS, Nerurkar G, Lawrence DJ. Enhanced hydrogen at the lunar poles: New insights from the detection of epithermal and fast neutron signatures. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2012je004112] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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10
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Prettyman TH, Mittlefehldt DW, Yamashita N, Lawrence DJ, Beck AW, Feldman WC, McCoy TJ, McSween HY, Toplis MJ, Titus TN, Tricarico P, Reedy RC, Hendricks JS, Forni O, Le Corre L, Li JY, Mizzon H, Reddy V, Raymond CA, Russell CT. Elemental mapping by Dawn reveals exogenic H in Vesta's regolith. Science 2012; 338:242-6. [PMID: 22997135 DOI: 10.1126/science.1225354] [Citation(s) in RCA: 186] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Using Dawn's Gamma Ray and Neutron Detector, we tested models of Vesta's evolution based on studies of howardite, eucrite, and diogenite (HED) meteorites. Global Fe/O and Fe/Si ratios are consistent with HED compositions. Neutron measurements confirm that a thick, diogenitic lower crust is exposed in the Rheasilvia basin, which is consistent with global magmatic differentiation. Vesta's regolith contains substantial amounts of hydrogen. The highest hydrogen concentrations coincide with older, low-albedo regions near the equator, where water ice is unstable. The young, Rheasilvia basin contains the lowest concentrations. These observations are consistent with gradual accumulation of hydrogen by infall of carbonaceous chondrites--observed as clasts in some howardites--and subsequent removal or burial of this material by large impacts.
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Affiliation(s)
- Thomas H Prettyman
- Planetary Science Institute, 1700 East Fort Lowell, Suite 106, Tucson, AZ 85719-2395, USA.
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11
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Mitrofanov I, Litvak M, Sanin A, Malakhov A, Golovin D, Boynton W, Droege G, Chin G, Evans L, Harshman K, Fedosov F, Garvin J, Kozyrev A, McClanahan T, Milikh G, Mokrousov M, Starr R, Sagdeev R, Shevchenko V, Shvetsov V, Tret'yakov V, Trombka J, Varenikov A, Vostrukhin A. Testing polar spots of water-rich permafrost on the Moon: LEND observations onboard LRO. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011je003956] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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12
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Sanin AB, Mitrofanov IG, Litvak ML, Malakhov A, Boynton WV, Chin G, Droege G, Evans LG, Garvin J, Golovin DV, Harshman K, McClanahan TP, Mokrousov MI, Mazarico E, Milikh G, Neumann G, Sagdeev R, Smith DE, Starr RD, Zuber MT. Testing lunar permanently shadowed regions for water ice: LEND results from LRO. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011je003971] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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13
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Litvak ML, Mitrofanov IG, Sanin A, Malakhov A, Boynton WV, Chin G, Droege G, Evans LG, Garvin J, Golovin DV, Harshman K, McClanahan TP, Mokrousov MI, Mazarico E, Milikh G, Neumann G, Sagdeev R, Smith DE, Starr R, Zuber MT. Global maps of lunar neutron fluxes from the LEND instrument. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011je003949] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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14
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Miller RS. Statistics for orbital neutron spectroscopy of the Moon and other airless planetary bodies. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011je003984] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Lawrence DJ, Eke VR, Elphic RC, Feldman WC, Funsten HO, Prettyman TH, Teodoro LFA. Technical Comment on “Hydrogen Mapping of the Lunar South Pole Using the LRO Neutron Detector Experiment LEND”. Science 2011; 334:1058-c. [DOI: 10.1126/science.1203341] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- David J. Lawrence
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
| | - Vincent R. Eke
- Institute for Computational Cosmology, Durham University, Durham DH1 3LE, UK
| | | | | | | | | | - Luis F. A. Teodoro
- Bay Area Environmental Research Institute, NASA Ames Research Center, Moffett Field, CA 94035, USA
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Maurice S, Feldman W, Diez B, Gasnault O, Lawrence DJ, Pathare A, Prettyman T. Mars Odyssey neutron data: 1. Data processing and models of water-equivalent-hydrogen distribution. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011je003810] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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McCord TB, Taylor LA, Combe JP, Kramer G, Pieters CM, Sunshine JM, Clark RN. Sources and physical processes responsible for OH/H2O in the lunar soil as revealed by the Moon Mineralogy Mapper (M3). ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010je003711] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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18
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Mitrofanov IG, Sanin AB, Boynton WV, Chin G, Garvin JB, Golovin D, Evans LG, Harshman K, Kozyrev AS, Litvak ML, Malakhov A, Mazarico E, McClanahan T, Milikh G, Mokrousov M, Nandikotkur G, Neumann GA, Nuzhdin I, Sagdeev R, Shevchenko V, Shvetsov V, Smith DE, Starr R, Tretyakov VI, Trombka J, Usikov D, Varenikov A, Vostrukhin A, Zuber MT. Hydrogen mapping of the lunar south pole using the LRO neutron detector experiment LEND. Science 2010; 330:483-6. [PMID: 20966247 DOI: 10.1126/science.1185696] [Citation(s) in RCA: 212] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Hydrogen has been inferred to occur in enhanced concentrations within permanently shadowed regions and, hence, the coldest areas of the lunar poles. The Lunar Crater Observation and Sensing Satellite (LCROSS) mission was designed to detect hydrogen-bearing volatiles directly. Neutron flux measurements of the Moon's south polar region from the Lunar Exploration Neutron Detector (LEND) on the Lunar Reconnaissance Orbiter (LRO) spacecraft were used to select the optimal impact site for LCROSS. LEND data show several regions where the epithermal neutron flux from the surface is suppressed, which is indicative of enhanced hydrogen content. These regions are not spatially coincident with permanently shadowed regions of the Moon. The LCROSS impact site inside the Cabeus crater demonstrates the highest hydrogen concentration in the lunar south polar region, corresponding to an estimated content of 0.5 to 4.0% water ice by weight, depending on the thickness of any overlying dry regolith layer. The distribution of hydrogen across the region is consistent with buried water ice from cometary impacts, hydrogen implantation from the solar wind, and/or other as yet unknown sources.
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Affiliation(s)
- I G Mitrofanov
- Institute for Space Research of the Russian Academy of Science, 117997 Moscow, Russia.
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Paige DA, Siegler MA, Zhang JA, Hayne PO, Foote EJ, Bennett KA, Vasavada AR, Greenhagen BT, Schofield JT, McCleese DJ, Foote MC, DeJong E, Bills BG, Hartford W, Murray BC, Allen CC, Snook K, Soderblom LA, Calcutt S, Taylor FW, Bowles NE, Bandfield JL, Elphic R, Ghent R, Glotch TD, Wyatt MB, Lucey PG. Diviner Lunar Radiometer Observations of Cold Traps in the Moon's South Polar Region. Science 2010; 330:479-82. [DOI: 10.1126/science.1187726] [Citation(s) in RCA: 294] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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20
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Lawrence DJ, Elphic RC, Feldman WC, Funsten HO, Prettyman TH. Performance of orbital neutron instruments for spatially resolved hydrogen measurements of airless planetary bodies. ASTROBIOLOGY 2010; 10:183-200. [PMID: 20298147 PMCID: PMC2956572 DOI: 10.1089/ast.2009.0401] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2009] [Accepted: 12/28/2009] [Indexed: 05/29/2023]
Abstract
Orbital neutron spectroscopy has become a standard technique for measuring planetary surface compositions from orbit. While this technique has led to important discoveries, such as the deposits of hydrogen at the Moon and Mars, a limitation is its poor spatial resolution. For omni-directional neutron sensors, spatial resolutions are 1-1.5 times the spacecraft's altitude above the planetary surface (or 40-600 km for typical orbital altitudes). Neutron sensors with enhanced spatial resolution have been proposed, and one with a collimated field of view is scheduled to fly on a mission to measure lunar polar hydrogen. No quantitative studies or analyses have been published that evaluate in detail the detection and sensitivity limits of spatially resolved neutron measurements. Here, we describe two complementary techniques for evaluating the hydrogen sensitivity of spatially resolved neutron sensors: an analytic, closed-form expression that has been validated with Lunar Prospector neutron data, and a three-dimensional modeling technique. The analytic technique, called the Spatially resolved Neutron Analytic Sensitivity Approximation (SNASA), provides a straightforward method to evaluate spatially resolved neutron data from existing instruments as well as to plan for future mission scenarios. We conclude that the existing detector--the Lunar Exploration Neutron Detector (LEND)--scheduled to launch on the Lunar Reconnaissance Orbiter will have hydrogen sensitivities that are over an order of magnitude poorer than previously estimated. We further conclude that a sensor with a geometric factor of approximately 100 cm(2) Sr (compared to the LEND geometric factor of approximately 10.9 cm(2) Sr) could make substantially improved measurements of the lunar polar hydrogen spatial distribution.
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Affiliation(s)
- David J Lawrence
- Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, USA.
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21
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Pieters CM, Goswami JN, Clark RN, Annadurai M, Boardman J, Buratti B, Combe JP, Dyar MD, Green R, Head JW, Hibbitts C, Hicks M, Isaacson P, Klima R, Kramer G, Kumar S, Livo E, Lundeen S, Malaret E, McCord T, Mustard J, Nettles J, Petro N, Runyon C, Staid M, Sunshine J, Taylor LA, Tompkins S, Varanasi P. Character and Spatial Distribution of OH/H2O on the Surface of the Moon Seen by M3 on Chandrayaan-1. Science 2009; 326:568-72. [DOI: 10.1126/science.1178658] [Citation(s) in RCA: 497] [Impact Index Per Article: 33.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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22
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Mitrofanov IG, Sanin AB, Golovin DV, Litvak ML, Konovalov AA, Kozyrev AS, Malakhov AV, Mokrousov MI, Tretyakov VI, Troshin VS, Uvarov VN, Varenikov AB, Vostrukhin AA, Shevchenko VV, Shvetsov VN, Krylov AR, Timoshenko GN, Bobrovnitsky YI, Tomilina TM, Grebennikov AS, Kazakov LL, Sagdeev RZ, Milikh GN, Bartels A, Chin G, Floyd S, Garvin J, Keller J, McClanahan T, Trombka J, Boynton W, Harshman K, Starr R, Evans L. Experiment LEND of the NASA Lunar Reconnaissance Orbiter for high-resolution mapping of neutron emission of the Moon. ASTROBIOLOGY 2008; 8:793-804. [PMID: 18844457 DOI: 10.1089/ast.2007.0158] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The scientific objectives of neutron mapping of the Moon are presented as 3 investigation tasks of NASA's Lunar Reconnaissance Orbiter mission. Two tasks focus on mapping hydrogen content over the entire Moon and on testing the presence of water-ice deposits at the bottom of permanently shadowed craters at the lunar poles. The third task corresponds to the determination of neutron contribution to the total radiation dose at an altitude of 50 km above the Moon. We show that the Lunar Exploration Neutron Detector (LEND) will be capable of carrying out all 3 investigations. The design concept of LEND is presented together with results of numerical simulations of the instrument's sensitivity for hydrogen detection. The sensitivity of LEND is shown to be characterized by a hydrogen detection limit of about 100 ppm for a polar reference area with a radius of 5 km. If the presence of ice deposits in polar "cold traps" is confirmed, a unique record of many millions of years of lunar history would be obtained, by which the history of lunar impacts could be discerned from the layers of water ice and dust. Future applications of a LEND-type instrument for Mars orbital observations are also discussed.
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Affiliation(s)
- I G Mitrofanov
- Institute for Space Research of the Russian Academy of Sciences, Moscow, Russia.
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23
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Solomon SC, McNutt RL, Watters TR, Lawrence DJ, Feldman WC, Head JW, Krimigis SM, Murchie SL, Phillips RJ, Slavin JA, Zuber MT. Return to Mercury: A Global Perspective on MESSENGER's First Mercury Flyby. Science 2008; 321:59-62. [DOI: 10.1126/science.1159706] [Citation(s) in RCA: 146] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Sean C. Solomon
- Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington, DC 20015, USA
- Space Department, Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
- Center for Earth and Planetary Studies, National Air and Space Museum, Smithsonian Institution, Washington, DC 20560, USA
- Planetary Science Institute, Tucson, AZ 85719, USA
- Department of Geological Sciences, Brown University, Providence, RI 02912, USA
| | - Ralph L. McNutt
- Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington, DC 20015, USA
- Space Department, Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
- Center for Earth and Planetary Studies, National Air and Space Museum, Smithsonian Institution, Washington, DC 20560, USA
- Planetary Science Institute, Tucson, AZ 85719, USA
- Department of Geological Sciences, Brown University, Providence, RI 02912, USA
| | - Thomas R. Watters
- Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington, DC 20015, USA
- Space Department, Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
- Center for Earth and Planetary Studies, National Air and Space Museum, Smithsonian Institution, Washington, DC 20560, USA
- Planetary Science Institute, Tucson, AZ 85719, USA
- Department of Geological Sciences, Brown University, Providence, RI 02912, USA
| | - David J. Lawrence
- Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington, DC 20015, USA
- Space Department, Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
- Center for Earth and Planetary Studies, National Air and Space Museum, Smithsonian Institution, Washington, DC 20560, USA
- Planetary Science Institute, Tucson, AZ 85719, USA
- Department of Geological Sciences, Brown University, Providence, RI 02912, USA
| | - William C. Feldman
- Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington, DC 20015, USA
- Space Department, Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
- Center for Earth and Planetary Studies, National Air and Space Museum, Smithsonian Institution, Washington, DC 20560, USA
- Planetary Science Institute, Tucson, AZ 85719, USA
- Department of Geological Sciences, Brown University, Providence, RI 02912, USA
| | - James W. Head
- Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington, DC 20015, USA
- Space Department, Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
- Center for Earth and Planetary Studies, National Air and Space Museum, Smithsonian Institution, Washington, DC 20560, USA
- Planetary Science Institute, Tucson, AZ 85719, USA
- Department of Geological Sciences, Brown University, Providence, RI 02912, USA
| | - Stamatios M. Krimigis
- Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington, DC 20015, USA
- Space Department, Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
- Center for Earth and Planetary Studies, National Air and Space Museum, Smithsonian Institution, Washington, DC 20560, USA
- Planetary Science Institute, Tucson, AZ 85719, USA
- Department of Geological Sciences, Brown University, Providence, RI 02912, USA
| | - Scott L. Murchie
- Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington, DC 20015, USA
- Space Department, Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
- Center for Earth and Planetary Studies, National Air and Space Museum, Smithsonian Institution, Washington, DC 20560, USA
- Planetary Science Institute, Tucson, AZ 85719, USA
- Department of Geological Sciences, Brown University, Providence, RI 02912, USA
| | - Roger J. Phillips
- Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington, DC 20015, USA
- Space Department, Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
- Center for Earth and Planetary Studies, National Air and Space Museum, Smithsonian Institution, Washington, DC 20560, USA
- Planetary Science Institute, Tucson, AZ 85719, USA
- Department of Geological Sciences, Brown University, Providence, RI 02912, USA
| | - James A. Slavin
- Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington, DC 20015, USA
- Space Department, Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
- Center for Earth and Planetary Studies, National Air and Space Museum, Smithsonian Institution, Washington, DC 20560, USA
- Planetary Science Institute, Tucson, AZ 85719, USA
- Department of Geological Sciences, Brown University, Providence, RI 02912, USA
| | - Maria T. Zuber
- Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington, DC 20015, USA
- Space Department, Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
- Center for Earth and Planetary Studies, National Air and Space Museum, Smithsonian Institution, Washington, DC 20560, USA
- Planetary Science Institute, Tucson, AZ 85719, USA
- Department of Geological Sciences, Brown University, Providence, RI 02912, USA
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Prettyman TH, Hagerty JJ, Elphic RC, Feldman WC, Lawrence DJ, McKinney GW, Vaniman DT. Elemental composition of the lunar surface: Analysis of gamma ray spectroscopy data from Lunar Prospector. ACTA ACUST UNITED AC 2006. [DOI: 10.1029/2005je002656] [Citation(s) in RCA: 283] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | - J. J. Hagerty
- Los Alamos National Laboratory; Los Alamos New Mexico USA
| | - R. C. Elphic
- Los Alamos National Laboratory; Los Alamos New Mexico USA
| | - W. C. Feldman
- Los Alamos National Laboratory; Los Alamos New Mexico USA
| | - D. J. Lawrence
- Los Alamos National Laboratory; Los Alamos New Mexico USA
| | - G. W. McKinney
- Los Alamos National Laboratory; Los Alamos New Mexico USA
| | - D. T. Vaniman
- Los Alamos National Laboratory; Los Alamos New Mexico USA
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