P. G. Lucey

University of Hawaiʻi at Mānoa, Honolulu, Hawaii, United States

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Publications (599)718.75 Total impact

  • American Mineralogist 10/2014; · 2.20 Impact Factor
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    ABSTRACT: The Lunar Orbiter Laser Altimeter (LOLA) measures the backscattered energy of the returning altimetric laser pulse at its wavelength of 1064 nm, and these data are used to map the reflectivity of the Moon at zero phase angle with a photometrically-uniform data set. Global maps have been produced at 4 pixels per degree (about 8 km at the equator) and 2-km resolution within 20 degrees latitude of each pole. The zero-phase geometry is insensitive to lunar topography, so these data enable characterization of subtle variations in lunar albedo, even at high latitudes where such measurements are not possible with the Sun as the illumination source. The geometric albedo of the Moon at 1064 nm was estimated from these data with absolute calibration derived from the Kaguya Multiband Imager and extrapolated to visual wavelengths. The LOLA estimates are within 2σ of historical measurements of geometric albedo. No consistent latitude-dependent variations in reflectance are observed, suggesting that solar wind does not dominate space-weathering processes that modify lunar reflectance. The average normal albedo of the Moon is found to be much higher than that of Mercury consistent with prior measurements, but the normal albedo of the lunar maria is similar to that of Mercury suggesting a similar abundance of space weathering products. Regions within permanent shadow in the polar-regions are found to be more reflective than polar surfaces that are sometimes illuminated. Limiting analysis to data with slopes less than ten degrees eliminates variations in reflectance due to mass wasting and shows a similar increased reflectivity within permanent polar shadow. Steep slopes within permanent shadow are also more reflective than similar slopes that experience at least some illumination. Water frost and a reduction in effectiveness of space weathering are offered as possible explanations for the increased reflectivity of permanent shadow; porosity is largely ruled out as the sole explanation. The south polar crater Shackleton is found to be among the most reflective craters in its size range globally, but is not the most reflective, so mass wasting cannot be ruled out as a cause for the crater's anomalous reflectance. Models of the abundance of ice needed to account for the reflectance anomaly range from 3 to 14 % by weight or area depending on assumptions regarding the effects of porosity on reflectance and whether ice is present as patches or is well-mixed in the regolith. If differences in nanophase iron abundances are responsible for the anomaly, the permanently shadowed regions have between 50 and 80% the abundance of nanophase iron in mature lunar soil.
    Journal of Geophysical Research: Planets. 07/2014;
  • SPIE Defense + Security; 06/2014
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    ABSTRACT: Chemical micro-imaging is a powerful tool for the detection and identification of analytes of interest against a cluttered background (i.e. trace explosive particles left behind in a fingerprint). While a variety of groups have demonstrated the efficacy of Raman instruments for these applications, point by point or line by line acquisition of a targeted field of view (FOV) is a time consuming process if it is to be accomplished with useful spatial resolutions. Spectrum Photonics has developed and demonstrated a prototype system utilizing long wave infrared hyperspectral microscopy, which enables the simultaneous collection of LWIR reflectance spectra from 8-14 μm in a 30 x 7 mm FOV with 30 μm spatial resolution in 30 s. An overview of the uncooled Sagnac-based LWIR HSM system will be given, emphasizing the benefits of this approach. Laboratory Hyperspectral data collected from custom mixtures and fingerprint residues is shown, focusing on the ability of the LWIR chemical micro-imager to detect chemicals of interest out of a cluttered background.
    SPIE Sensing Technology + Applications; 05/2014
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    ABSTRACT: Fourier transform spectroscopy is a widely employed method for obtaining visible and infrared spectral imagery, with applications ranging from the desktop to remote sensing. Most fielded Fourier transform spectrometers (FTS) employ the Michelson interferometer and measure the spectrum encoded in a time-varying signal imposed by the source spectrum interaction with the interferometer. A second, less widely used form of FTS is the spatial FTS, where the spectrum is encoded in a pattern sampled by a detector array. Recently we described using a Fabry-Perot interferometer, with a deliberately wedged gap geometry and engineered surface reflectivities, to produce an imaging spatial FTS. The Fabry-Perot interferometer can be much lighter and more compact than a conventional interferometer configuration, thereby making them suitable for portable and handheld applications. This approach is suitable for use over many spectral regimes of interest, including visible and infrared regions. Primary efforts to date have focused on development and demonstration of long wave infrared (LWIR) spectral imagers. The LWIR version of the miniaturized Fabry-Perot has been shown to be effective for various applications including spectral imaging-based chemical detection. The compact LWIR spectral imager employs uncooled optics and a microbolometer camera; a handheld version is envisioned for future development. Recent advancements associated with the spatial Fourier Transform imaging spectrometer system are described.
    SPIE Sensing Technology + Applications; 05/2014
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    ABSTRACT: We use lab and Diviner mid-IR data along with spectral mixture analysis of M^3 data to characterize areas of the Moon that are olivine-bearing and pyroxene-poor.
    02/2014;
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    ABSTRACT: We constrain the amount of mantle in the crust and the depth-diameter ratio of the largest basins using mineral mixing models and a small crater spectral survey.
    02/2014;
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    ABSTRACT: Mineral maps derived from the Kaguya Multiband Imager of lunar crater central peaks are augmented using Diviner CF maps to better represent plg/pyx/olv abundances.
    02/2014;
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    ABSTRACT: The darker it gets the brighter it is.
    02/2014;
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    ABSTRACT: We present new mineral maps of Moscoviense Basin. The mineralogical diversity present makes MB a compelling target for future exploration and sample return.
    02/2014;
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    M. A. Riner, P. G. Lucey
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    ABSTRACT: Using geologic context and spectral modeling, we find immature crater ejecta on Mercury has >4 times more space weathering than the most mature lunar samples.
    02/2014;
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    ABSTRACT: Compositions of lunar olivines are estimated using MGM-based techniques. Our approach provides rough but absolute compositional assessments.
    02/2014;
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    ABSTRACT: An infrared reflectance lidar obtains multispectral data near 3 µm to map ice in the lunar polar regions. Visible fluorescence seeks organics.
    02/2014;
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    ABSTRACT: A prototype compact remote LIBS, Raman, and laser-induced fluorescence spectroscopy instrument for planetary science has been produced and extensively tested.
    02/2014;
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    M. Lemelin, P. G. Lucey, E. Song
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    ABSTRACT: Central peak compositions derived from Kaguya MI data show only weak correlation of plagioclase with proximity to the mantle derived from GRAIL data.
    02/2014;
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    ABSTRACT: Impact modeling of the SPA basin, multispectral and petrologic data all suggest that the upper mantle of the Moon is dominated by orthopyroxene, not olivine.
    02/2014;
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    ABSTRACT: [1] We model lunar ilmenite abundances over Mare Australe and Mare Ingenii regions using a new approach; we integrate Lunar Reconnaissance Orbiter Wide Angle Camera (WAC) and Clementine UVVIS/NIR data to obtain a 14 band mosaic (320-2,000 nm) and model it using Hapke's radiative transfer modeling techniques. We calculate a “maximum stoichiometrically possible ilmenite content”, based upon Clementine-derived lunar surface estimates of TiO2 and the budget of TiO2 physically allowable in the ilmenite crystal structure, and use it as a constraint in our model. Using radiative transfer equations, we also compute spectra for a variety of modal mineral proportions of orthopyroxene, clinopyroxene, plagioclase, olivine, and ilmenite, while varying grain size, chemistry, and degree of maturity, and find the closest match between the modeled spectra and the spectra of the less mature pixels (OMAT ≥ 0.2) in the 14 band mosaic. We validate our model methodology with lunar soil spectra acquired by the Lunar Soil Characterization Consortium. Our model results show that the integrated WAC-UVVIS/NIR data and the UVVIS/NIR data overestimate ilmenite abundances in average by 8.80 wt.% and 7.97 wt.% respectively in our modeling when a constraint in ilmenite of 20 wt.% is used, for laboratory measured lunar soils spectra. When the maximum stoichiometrically possible ilmenite content is used as a constraint, the integrated WAC-UVVIS/NIR data gives slightly more accurate ilmenite abundance estimation (± 2.87 wt.%) than when using only UVVIS/NIR data (± 3.04 wt.%). We find ilmenite concentrations range between 0-11 wt.% in Mare Australe and between 0-6 wt.% in Mare Ingenii region. Ilmenite abundances between 4-7 wt.% are exposed in Mare Australe, whereas ilmenite abundances between 7-11 wt.% are found on the walls of 0.6-11.8 km diameter craters within Mare Australe.
    Journal of Geophysical Research: Planets. 12/2013;
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    ABSTRACT: Galactic cosmic rays are a potential energy source to stimulate organic synthesis from simple ices. The recent detection of organic molecules at the polar regions of the Moon by LCROSS (Colaprete, A. et al. [2010]. Science 330, 463–468, http://dx.doi.org/10.1126/science.1186986), and possibly at the poles of Mercury (Paige, D.A. et al. [2013]. Science 339, 300–303, http://dx.doi.org/10.1126/science.1231106), introduces the question of whether the organics were delivered by impact or formed in situ. Laboratory experiments show that high energy particles can cause organic production from simple ices. We use a Monte Carlo particle scattering code (MCNPX) to model and report the flux of GCR protons at the surface of the Moon and report radiation dose rates and absorbed doses at the Moon's surface and with depth as a result of GCR protons and secondary particles, and apply scaling factors to account for contributions to dose from heavier ions. We compare our results with dose rate measurements by the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) experiment on Lunar Reconnaissance Orbiter (Schwadron, N.A. et al. [2012]. J. Geophys. Res. 117, E00H13, http://dx.doi.org/10.1029/2011JE003978) and find them in good agreement, indicating that MCNPX can be confidently applied to studies of radiation dose at and within the surface of the Moon. We use our dose rate calculations to conclude that organic synthesis is plausible well within the age of the lunar polar cold traps, and that organics detected at the poles of the Moon may have been produced in situ. Our dose rate calculations also indicate that galactic cosmic rays can induce organic synthesis within the estimated age of the dark deposits at the pole of Mercury that may contain organics.
    Icarus 11/2013; 226(2):1192-1200. · 3.16 Impact Factor
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    ABSTRACT: The Thermal Hyperspectral Imager (THI) is a low cost, low mass, power efficient instrument designed to acquire hyperspectral remote sensing data in the long-wave infrared. The instrument has been designed to satisfy mass, volume, and power constraints necessary to allow for its accommodation in a 95 kg micro-satellite bus, designed by staff and students at the University of Hawai'i. THI acquires approximately 30 separate spectral bands in the 8–14 μm wavelength region, at 16 wavenumber resolution. Rather than using filtering or dispersion to generate the spectral information, THI uses an interferometric technique. Light from the scene is focused onto an uncooled microbolometer detector array through a stationary interferometer, causing the light incident at each detector at any instant in time to be phase shifted by an optical path difference which varies linearly across the array in the along-track dimension. As platform motion translates the detector array in the along-track direction at a rate of approximately one pixel per frame (the camera acquires data at 30 Hz) the radiance from each scene element can be sampled at each OPD, thus generating an interferogram. Spectral radiance as a function of wavelength is subsequently obtained for each scene element using standard Fourier transform techniques. Housed in a pressure vessel to shield COTS parts from the space environment, the total instrument has a mass of 15 kg. Peak power consumption, largely associated with the calibration procedure, is <90 W. From a nominal altitude of 550 km the resulting data would have a spatial resolution of approximately 300 m. Although an individual imaging event yields approximately 1 Gbit of raw uncompressed data, onboard processing (to convert the interferograms into a conventional spectral hypercube) can reduce this to tens of Mega bits per scene. In this presentation we will describe (a) the rationale for the project, (b) the instrument design, and (c) how the data are processed. Finally we will present data acquired by THI on a laboratory microscope stage to demonstrate the spectro-radiometric quality of the data that the instrument can provide.
    Acta Astronautica 06/2013; 87:182–192. · 0.70 Impact Factor
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    ABSTRACT: The University of Hawaii has developed a concept to ruggedize an existing thermal infrared hyperspectral system for use in the NASA SIERRA UAV. The Hawaii Institute of Geophysics and Planetology has developed a suite of instruments that acquire high spectral resolution thermal infrared image data with low mass and power consumption by combining microbolometers with stationary interferometers, allowing us to achieve hyperspectral resolution (20 wavenumbers between 8 and 14 micrometers), with signal to noise ratios as high as 1500:1. Several similar instruments have been developed and flown by our research group. One recent iteration, developed under NASA EPSCoR funding and designed for inclusion on a microsatellite (Thermal Hyperspectral Imager; THI), has a mass of 11 kg. Making THI ready for deployment on the SIERRA will involve incorporating improvements made in building nine thermal interferometric hyperspectral systems for commercial and government sponsors as part of HIGP’s wider program. This includes: a) hardening the system for operation in the SIERRA environment, b) compact design for the calibration system, c) reconfiguring software for autonomous operation, d) incorporating HIGP-developed detectors with increased responsiveness at the 8 micron end of the TIR range, and e) an improved interferometer to increase SNR for imaging at the SIERRA’s air speed. UAVs provide a unique platform for science investigations that the proposed instrument, UAVTHI, will be well placed to facilitate (e.g. very high temporal resolution measurements of temporally dynamic phenomena, such as wildfires and volcanic ash clouds). Its spectral range is suited to measuring gas plumes, including sulfur dioxide and carbon dioxide, which exhibit absorption features in the 8 to 14 micron range.
    SPIE Defense, Security, and Sensing; 05/2013

Publication Stats

5k Citations
718.75 Total Impact Points

Institutions

  • 1989–2014
    • University of Hawaiʻi at Mānoa
      • Institute of Geophysics and Planetology
      Honolulu, Hawaii, United States
  • 2002–2012
    • University of Hawaiʻi at Hilo
      Hilo, Hawaii, United States
  • 1278–2012
    • Honolulu University
      Honolulu, Hawaii, United States
  • 2010
    • Carnegie Institution for Science
      Washington, West Virginia, United States
    • California Institute of Technology
      • Jet Propulsion Laboratory
      Pasadena, CA, United States
    • Stony Brook University
      • Department of Geosciences
      Stony Brook, NY, United States
    • University of California, Los Angeles
      • Department of Earth and Space Sciences (ESS)
      Los Angeles, CA, United States
  • 1999–2010
    • University of Hawai'i System
      Honolulu, Hawaii, United States
  • 1997–2005
    • Los Alamos National Laboratory
      • Space Science and Applications Group
      Los Alamos, NM, United States
    • United States Geological Survey
      Reston, Virginia, United States
  • 1998–2000
    • Northwestern University
      Evanston, Illinois, United States
    • Arizona Geological Survey - AZGS
      Tucson, Arizona, United States
  • 1997–1998
    • The University of Arizona
      • Department of Planetary Sciences
      Tucson, Arizona, United States
  • 1988
    • NASA
      Washington, West Virginia, United States