G. Droege

University of Arizona

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W. V. Boynton

University of Arizona

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И. Г. Митрофанов

Space Research Institute

K. Harshman

University of Arizona

R. Starr

Catholic University of America

A. Malakhov

National Research University Higher School of Economics

L. G. Evans

Oak Ridge National Laboratory

G. Chin

Goddard Space Flight Center

M. L. Litvak

Space Research Institute

G. M. Milikh

University of Maryland, College Park

J. B. Garvin

Goddard Space Flight Center

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Goddard Space Flight Center

Space Research Institute

Russian Academy of Sciences

University of Arizona

University of Maryland, College Park

Massachusetts Institute of Technology

Planetary Science Institute

Jet Propulsion Laboratory

Catholic University of America

Johns Hopkins University Applied Physics Laboratory

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Correlation of Illumination and Topography Factors with Epithermal Neutron measurements at the Lunar Poles using the Lunar Reconnaissance Orbiter (LRO), Lunar Exploration Neutron Detector (LEND)

AGUFM (2010)

T. P. McClanahan И. Г. Митрофанов W. V. Boynton L. G. Evans G. Droege

Orbiter

Clementine (nuclear reactor)

Moon landing

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T. P. McClanahan И. Г. Митрофанов W. V. Boynton G. Chin G. Droege

We correlate Lunar Reconnaisance Orbiter's (LRO) Lunar Exploration Neutron Detector (LEND) and the Lunar Prospector Neutron Spectrometer's (LPNS) orbital epithermal neutron maps of the Lunar high-latitudes with co-registered illumination maps derived from the Lunar Orbiter Laser Altimeter (LOLA) topography. Epithermal neutron count rate maps were derived from the LEND: 1) Collimated Sensor for Epithermal Neutrons, CSETNI-4 2) Uncollimated Sensor for Epithermal Neutrons, SETN and the Uncollimated Lunar Prospector: 3) Low-altitude and 4) High-altitude mapping phases. In this abstract we illustrate 1) and 3) and include 2) and 4) in our presentation. The correlative study provides unique perspectives on the regional epithermal neutron fluences from the Lunar polar regions under different detector and altitude configurations.

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Neutron Detection

Collimated light

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Insolation Effects on Lunar Hydrogen: Correlated Observations from LEND and LOLA

T. P. McClanahan И. Г. Митрофанов W. V. Boynton G. Droege J. B. Garvin

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Testing polar spots of water‐rich permafrost on the Moon: LEND observations onboard LRO

Journal of Geophysical Research Atmospheres (2012)

И. Г. Митрофанов M. L. Litvak А. Б. Санин A. Malakhov D. V. Golovin

Results are presented for the LEND instrument onboard LRO for the detection of local spots of suppression and excess of epithermal neutron emission at the lunar poles. Twelve local Neutron Suppression Regions (NSRs) and Neutron Excess Regions (NERs) are detected. It is shown using the data from the LOLA and Diviner instruments that six NSRs have the empirical property “ less local irradiation and lower temperature – fewer local neutrons. ” These NSRs may be identified with spots of water‐ice rich permafrost on the Moon. It is shown that detected NSRs are include in both permanently shadowed and illuminated areas, and they are not coincident with Permanently Shadowed Regions (PSRs) at the bottom of polar craters, as has been commonly expected before LEND presented neutron data with high spatial resolution.

10.1029/2011je003956

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High spatial resolution studies of epithermal neutron emission from the lunar poles: Constraints on hydrogen mobility

Journal of Geophysical Research Atmospheres (2012)

W. V. Boynton G. Droege И. Г. Митрофанов T. P. McClanahan А. Б. Санин

The data from the collimated sensors of the LEND instrument are shown to be of exceptionally high quality. Counting uncertainties are about 0.3% relative and are shown to be the only significant source of random error, thus conclusions based on small differences in count rates are valid. By comparison with the topography of Shoemaker crater, the spatial resolution of the instrument is shown to be consistent with the design value of 5 km for the radius of the circle over which half the counts from the lunar surface would be determined. The observed epithermal‐neutron suppression factor due to the hydrogen deposit in Shoemaker crater of 0.25 ± 0.04 cps is consistent with the collimated field‐of‐view rate of 1.7 cps estimated by Mitrofanov et al. (2010a). The statistical significance of the neutron suppressed regions (NSRs) relative to the larger surrounding polar region is demonstrated, and it is shown that they are not closely related to the permanently shadowed regions. There is a significant increase in H content in the polar regions independent of the H content of the NSRs. The non‐NSR H content increases directly with latitude, and the rate of increase is virtually identical at both poles. There is little or no increase with latitude outside the polar region. Various mechanisms to explain this steep increase in the non‐NSR polar H with latitude are investigated, and it is suggested that thermal volatilization is responsible for the increase because it is minimized at the low surface temperatures close to the poles.

Collimated light

10.1029/2011je003979

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LEND neutron data processing for the mapping of the Moon

Journal of Geophysical Research Atmospheres (2012)

M. L. Litvak И. Г. Митрофанов А. Б. Санин D. V. Golovin A. Malakhov

The Lunar Exploration Neutron Detector (LEND) aboard the Lunar Reconnaissance Orbiter (LRO) has been mapping the neutron flux from the Moon since July 2009. LEND has four different types of neutron detectors which allow a comprehensive study of lunar neutron emission: a pair of omnidirectional sensors for thermal and epithermal neutrons, a pair of Doppler filter sensors for thermal neutrons, four collimated sensors of epithermal neutrons, and a sensor of high‐energy neutrons. This paper describes the data reduction procedures to convert the raw data into the higher‐level PDS products containing neutron‐counting rate maps of the Moon.

Data Processing

10.1029/2011je004035

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Local Spots of Lunar Water-Ice Permafrost in Shadow and in Sunlight, as Seen by LEND/LRO

Annual Meeting of the Lunar Exploration Analysis Group (2011)

И. Г. Митрофанов M. Litvak A. Sanin A. Malakhov D. I. Golovin

BY LEND/LRO. I. G. Mitrofanov , M. L. Litvak, A. B. Sanin, A. A. Malakhov, D. V. Golovin, W. Boynton, G. Droege, G. Chin, L. Evens, K. Harshman, J. Garvin, A. Kozyrev, T. McClanahan, G. Milikh, M. Mokrousov, R. Starr, R. Sagdeev, V. Shevchenko, V. Shvetsov, V. Tret’yakov, J. Trombka, A. Varenikov and A. Vostrukhin. Institute for Space Research of Russian Academy of Science, 117997 Moscow, Russia, imitrofa@space.ru, University of Arizona, Tucson, USA, NASA Goddard Space Flight Center, Greenbelt, USA, Computer Science Corporation, Greenbelt, USA, University of Maryland, College Park, USA, Catholic University, Washington DC, USA, Sternberg Astronomical Institute of Moscow State University, Moscow, Russia, Joint Institute of Nuclear Energy, Dubna, Moscow.

space science

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Insolation Effects on Lunar Hydrogen: Correlated observations of LEND and Second Order Insolation Effects Derived from LOLA Modeling

AGUFM (2011)

T. P. McClanahan E. Mazarico G. Droege Lunar Reconnaissance Orbiter Lend Team Lola Team

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Distribution of Hydrogen in the Lunar Polar Regions

AGUFM (2011)

W. V. Boynton G. Droege И. Г. Митрофанов T. P. McClanahan

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Evidence for the Sequestration of Hydrogen-Bearing Volatiles Towards the Moons Southern Pole-Facing Slopes

Lunar and Planetary Science Conference (2015)

T. P. McClanahan И. Г. Митрофанов W. V. Boynton G. Chin J. Bodnarik

The Lunar Exploration Neutron Detector (LEND) onboard the Lunar Reconnaissance Orbiter (LRO) detects a widespread suppression of the epithermal neutron leakage flux that is coincident with the pole-facing slopes (PFS) of the Moon's southern hemisphere. Suppression of the epithermal neutron flux is consistent with an interpretation of enhanced concentrations of hydrogen-bearing volatiles within the upper meter of the regolith. Localized flux suppression in PFS suggests that the reduced solar irradiation and lowered temperature on PFS constrains volatility to a greater extent than in surrounding regions. Epithermal neutron flux mapped with LEND's Collimated Sensor for Epithermal Neutrons (CSETN) was analyzed as a function of slope geomorphology derived from the Lunar Orbiting Laser Altimeter (LOLA) and the results compared to co-registered maps of diurnally averaged temperature from the Diviner Lunar Radiometer Experiment and an averaged illumination map derived from LOLA. The suppression in the average south polar epithermal neutron flux on equator-facing slopes (EFS) and PFS (85-90 deg S) is 3.3 +/- 0.04% and 4.3 +/- 0.05% respectively (one-sigma-uncertainties), relative to the average count-rate in the latitude band 45-90 deg S. The discrepancy of 1.0 +/- 0.06% between EFS and PFS neutron flux corresponds to an average of approximately 23 parts-per-million-by-weight (ppmw) more hydrogen on PFS than on EFS. Results show that the detection of hydrogen concentrations on PFS is dependent on their spatial scale. Epithermal flux suppression on large scale PFS was found to be enhanced to 5.2 +/- 0.13%, a discrepancy of approximately 45 ppmw hydrogen relative to equivalent EFS. Enhanced poleward hydration of PFS begins between 50 deg S and 60 deg S latitude. Polar regolith temperature contrasts do not explain the suppression of epithermal neutrons on pole-facing slopes. The Supplemental on-line materials include supporting results derived from the uncollimated Lunar Prospector Neutron Spectrometer and the LEND Sensor for Epithermal Neutrons.

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