The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Bruce M. Jakosky - One of the best experts on this subject based on the ideXlab platform.
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Effects of topography on thermal infrared spectra of Planetary Surfaces
Journal of Geophysical Research, 2002Co-Authors: Joshua E. Colwell, Bruce M. JakoskyAbstract:[1] We use a thermal model with large-scale surface roughness to study the effects of topography and roughness on thermal infrared spectra of Planetary Surfaces. We study a range of roughness values, illumination geometries, and viewing geometries and find that surface roughness can strongly alter the slope of a thermal infrared spectrum, especially for large solar incidence angles. This roughness-induced slope in the spectrum can shift the location of the Christiansen frequency and should be removed in order to study the mineralogy and other surface properties. The effect is minimized for viewing near zero phase angle. This makes it possible to measure large-scale roughness by comparing thermal infrared spectra taken near zero phase angle with those taken at a large solar incidence angle and nonzero phase angle. Changes in apparent emissivity with wavelength in the thermal infrared due to roughness are calculated for Clementine longwave-infrared images of the Moon. These roughness-induced spectral slopes observed for the Moon are 5% between 5 and 8 microns for regions of moderate topography.
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A LiF silicon sandwich counter to measure water content of Planetary Surfaces
Information Systems Research, 1997Co-Authors: D. M. Drake, Benton C. Clark, Bruce M. Jakosky, Robert C. Reedy, Steven W. SquyresAbstract:Planetary Surfaces. D. M. Drake1, Benton C. Clark 2, Bruce M. Jakosky 3, Robert Reedy 4, and Steven W. Squyres 5. 1. Amparo Corporation, Santa Fe, NM 87501,drake@nis.lanl.gov; 2. Lockheed Martin Astronautics Group, Denver CO 80201; 3. Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309-0392; 4. NIS-2, Los Alamos National Laboratory, Los Alamos, NM 87545; 5. Laboratory for Planetary Studies, Space Sciences Building, Cornell University, Ithaca, NY 14853-6802.
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new laboratory measurements of mid ir emission spectra of simulated Planetary Surfaces
Journal of Geophysical Research, 1996Co-Authors: Bradley G Henderson, P G Lucey, Bruce M. JakoskyAbstract:We present emission spectra of particulate quartz measured in an environment chamber designed to simulate the conditions on actual Planetary Surfaces. The goal was to investigate near-surface thermal gradients and their effects on emission spectra for other Planetary environments. Our experiment parallels that of Logan et al. [1973] but is different, in that our samples were heated at the base by a temperature-controlled hot plate rather than from above by a solar lamp in order to separate infrared surface cooling from solar heating effects. Our spectra show prominent emission peaks which are attributed to the presence of near-surface thermal gradients created by infrared cooling of the uppermost layer of the material. The contrast of the emission peak is maximized under vacuum conditions, for which it is estimated that a temperature difference of at least 40 K existed within the top emission skin depth. The wavelength location of the emission peak occurs near the Christiansen wavelength at 7.35 μm but has been shifted by approximately 0.2 μm to shorter wavelengths. This result is in agreement with the earlier results of Logan et al. [1973] and points out that the existence of a thermal gradient violates the conditions required by Kirchoff's law, and therefore care should be taken when spectra of Surfaces on airless bodies are interpreted using emissivity spectra converted from reflectance data. Increasing the atmospheric pressure in the chamber increased the conductivity of the soil, mitigating the thermal gradient and decreasing the contrast of the emission maxima. Although thermal gradients complicate the interpretation of emission spectra of airless bodies, they tend to enhance certain spectral features, and therefore emission spectroscopy should be useful for remote sensing of the Surfaces of the Moon and Mercury.
Caleb I Fassett - One of the best experts on this subject based on the ideXlab platform.
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analysis of impact crater populations and the geochronology of Planetary Surfaces in the inner solar system
Journal of Geophysical Research, 2016Co-Authors: Caleb I FassettAbstract:Analyzing the density of impact craters on Planetary Surfaces is the only known technique for learning their ages remotely. As a result, crater statistics have been widely analyzed on the terrestrial planets, since the timing and rates of activity are critical to understanding geologic process and history. On the Moon, the samples obtained by the Apollo and Luna missions provide critical calibration points for cratering chronology. On Mercury, Venus, and Mars, there are no similarly firm anchors for cratering rates, but chronology models have been established by extrapolating from the lunar record or by estimating their impactor fluxes in other ways. This review provides a current perspective on crater population measurements and their chronological interpretation. Emphasis is placed on how ages derived from crater statistics may be contingent on assumptions that need to be considered critically. In addition, ages estimated from crater populations are somewhat different than ages from more familiar geochronology tools (e.g., radiometric dating). Resurfacing processes that remove craters from the observed population are particularly challenging to account for, since they can introduce geologic uncertainty into results or destroy information about the formation age of a surface. Regardless of these challenges, crater statistics measurements have resulted in successful predictions later verified by other techniques, including the age of the lunar maria, the existence of a period of heavy bombardment in the Moon's first billion years, and young volcanism on Mars.
Gabriele Arnold - One of the best experts on this subject based on the ideXlab platform.
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Infrared remote sensing of Planetary Surfaces: an overview, outstanding questions, and prospects
Proceedings of SPIE, 2013Co-Authors: Gabriele ArnoldAbstract:We owe a major part of our knowledge about surface composition and structure of solid Planetary Surfaces to infrared imaging and Fourier transform spectroscopy. Based on these methods, it succeeds to observe single Planetary objects in a global geo-scientific content. The topics of infrared surface studies are mineralogical composition analyses, measurement of surface temperature, thermal inertia, and photometric observation of surface regolith texture. The comparison of infrared with photogeologic data forms the essential basis for comparative studies in planetology. The present paper summarizes outstanding results by examples of ESA experiments like VIRTIS on Venus Express and Rosetta, PFS on Mars Express, MERTIS on Bepi Colombo, and TIRVIM on ExoMars, and provides an outlook for future plans. The instruments are described, and the interplay of disciplines like planetology, IR measuring techniques, and space flight engineering is demonstrated. Infrared remote sensing provides essential knowledge about the current state of solid Planetary Surfaces. This allows studying fundamental questions in comparative planetology.
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Exploring the solar system: the view of Planetary Surfaces with VIS/IR remote sensing methods
Proceedings of SPIE, 2011Co-Authors: Gabriele ArnoldAbstract:The structure of Planetary Surfaces unveils basic formation processes and evolution lines of different objects in the solar system, and often the view on the top of a planet is the only available information about it. Advanced remote sensing technologies on deep space missions are aimed at accessing a maximum of relevant data to characterize a Planetary object holistically. This approach requires concert strategies in Planetary and engineering science. In this framework VIS/IR spectroscopic remote sensing methods are key technologies for imaging Planetary atmospheres and Surfaces, for studying their composition, texture, structure and dynamics. Basing on these analyses it succeeds to observe the single objects in more global geo-scientific content. The paper focuses on main geo-scientific output coming from spectroscopic studies of Planetary Surfaces in conjunction with their interiors, atmospheres, and the interPlanetary space. It summarizes selected results of spectral studies onboard of the ESA deep space missions BepiColombo, Venus Express, Mars Express, and Rosetta. The corresponding spectral instruments are introduced. The complex conflation of special knowledge of the disciplines planetology, optical and IR measuring techniques, and space flight engineering is demonstrated in several examples. Finally, the paper gives an outlook of current developments for spectral studies in planned missions, and sums up some of the driving questions in Planetary science.
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Fourier transform spectroscopy in remote sensing of solid Planetary Surfaces
Vibrational Spectroscopy, 1993Co-Authors: Helmut Hirsch, Gabriele ArnoldAbstract:Abstract Fourier transform spectrometers have been used to obtain infrared emission spectra of solid Planetary Surfaces in the mid- and thermal-infrared region. This range is suitable for determining the mineralogical composition of the different Planetary objects because even the highest-frequency fundamentals of silicates and other minerals appear in this region. However, the analysis of the emission spectra of solid Surfaces is considerably complicated by the influence of morphological parameters on spectral behaviour. The Surfaces of most of the airless Planetary objects are covered with a regolith blanket. Particle size, grain shape, particle size distribution, the degree of covering and porosity of this fine-grained material strongly influence the thermal throughput and the spectral behaviour in the infrared. Laboratory emittance spectra of particulate minerals show that the spectral contrast of the fundamental vibration bands decreases with decreasing particle size. In the spectra of mineral powders with small grain sizes, weak overtone and combination tone bands instead of the vanishing fundamentals become increasingly important for the identification of minerals. Therefore, in the past infrared spectroscopy has been used rather sparingly for remote sensing. The chances for composition analysis of solid Surfaces are discussed in relation to instrumental requirements for Fourier spectroscopy during Planetary missions. An FT-IR spectrometer with its throughput and multiplex advantage is proposed for the spectroscopic sounding of the Planetary Surfaces. Moreover, the rotating reflector interferometer (RRI) is especially well adapted for space missions. It uses two retroreflectors in full aperture, integrated into a rotational device. The retroreflectors move along a circular path for some degrees, tailored to give medium resolution (0.5–5 cm −1 ) typical for space missions. Moreover, the RRI is suitable for lightweight, rugged and compact construction, which has minimum sensitivity to vibrations and shocks.
Carlos I Calle - One of the best experts on this subject based on the ideXlab platform.
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Electrostatic Phenomena on Planetary Surfaces
2017Co-Authors: Carlos I CalleAbstract:The diverse Planetary environments in the solar system react in somewhat different ways to the encompassing influence of the Sun. These different interactions define the electrostatic phenomena that take place on and near Planetary Surfaces. The desire to understand the electrostatic environments of Planetary Surfaces goes beyond scientific inquiry. These environments have enormous implications for both human and robotic exploration of the solar system. This book describes in some detail what is known about the electrostatic environment of the solar system from early and current experiments on Earth as well as what is being learned from the instrumentation on the space exploration missions (NASA, European Space Agency, and the Japanese Space Agency) of the last few decades. It begins with a brief review of the basic principles of electrostatics.
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Electrostatic Phenomena on Planetary Surfaces - The Martian electrostatic environment
Electrostatic Phenomena on Planetary Surfaces, 2017Co-Authors: Carlos I CalleAbstract:The diverse Planetary environments in the solar system react in somewhat different ways to the encompassing influence of the Sun. These different interactions define the electrostatic phenomena that take place on and near Planetary Surfaces. The desire to understand the electrostatic environments of Planetary Surfaces goes beyond scientific inquiry. These environments have enormous implications for both human and robotic exploration of the solar system. This book describes in some detail what is known about the electrostatic environment of the solar system from early and current experiments on Earth as well as what is being learned from the instrumentation on the space exploration missions (NASA, European Space Agency, and the Japanese Space Agency) of the last few decades. It begins with a brief review of the basic principles of electrostatics.
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Electrostatic Phenomena on Planetary Surfaces - The terrestrial electrostatic environment
Electrostatic Phenomena on Planetary Surfaces, 2017Co-Authors: Carlos I CalleAbstract:The diverse Planetary environments in the solar system react in somewhat different ways to the encompassing influence of the Sun. These different interactions define the electrostatic phenomena that take place on and near Planetary Surfaces. The desire to understand the electrostatic environments of Planetary Surfaces goes beyond scientific inquiry. These environments have enormous implications for both human and robotic exploration of the solar system. This book describes in some detail what is known about the electrostatic environment of the solar system from early and current experiments on Earth as well as what is being learned from the instrumentation on the space exploration missions (NASA, European Space Agency, and the Japanese Space Agency) of the last few decades. It begins with a brief review of the basic principles of electrostatics.
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Electrostatic Phenomena on Planetary Surfaces - The electrostatic environment of asteroids
Electrostatic Phenomena on Planetary Surfaces, 2017Co-Authors: Carlos I CalleAbstract:The diverse Planetary environments in the solar system react in somewhat different ways to the encompassing influence of the Sun. These different interactions define the electrostatic phenomena that take place on and near Planetary Surfaces. The desire to understand the electrostatic environments of Planetary Surfaces goes beyond scientific inquiry. These environments have enormous implications for both human and robotic exploration of the solar system. This book describes in some detail what is known about the electrostatic environment of the solar system from early and current experiments on Earth as well as what is being learned from the instrumentation on the space exploration missions (NASA, European Space Agency, and the Japanese Space Agency) of the last few decades. It begins with a brief review of the basic principles of electrostatics.
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Electrostatic Phenomena on Planetary Surfaces - The electrostatic environment of the Moon
Electrostatic Phenomena on Planetary Surfaces, 2017Co-Authors: Carlos I CalleAbstract:The diverse Planetary environments in the solar system react in somewhat different ways to the encompassing influence of the Sun. These different interactions define the electrostatic phenomena that take place on and near Planetary Surfaces. The desire to understand the electrostatic environments of Planetary Surfaces goes beyond scientific inquiry. These environments have enormous implications for both human and robotic exploration of the solar system. This book describes in some detail what is known about the electrostatic environment of the solar system from early and current experiments on Earth as well as what is being learned from the instrumentation on the space exploration missions (NASA, European Space Agency, and the Japanese Space Agency) of the last few decades. It begins with a brief review of the basic principles of electrostatics.
Edward Tunstel - One of the best experts on this subject based on the ideXlab platform.
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mobile robotic surveying performance for Planetary surface site characterization
Performance Metrics for Intelligent Systems, 2008Co-Authors: Edward TunstelAbstract:Robotic systems will perform mobile surveys for scientific and engineering purposes as part of future missions on lunar and Planetary Surfaces. With site characterization as a task objective various system configurations and surveying techniques are possible. This paper describes several examples of mobile surveying approaches using local and remote sensing configurations. A geometric measure of are a coverage performance is applied to each and relative performance in surveying a common area is characterized by expected performance trends. Performance metrics that solely express geometric aspects of the task are limited in utility as decision aids to mission operators. As such, the importance of enriching such metrics by incorporating additional attributes germane to surveying on Planetary Surfaces is highlighted.
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PerMIS - Mobile robotic surveying performance for Planetary surface site characterization
Proceedings of the 8th Workshop on Performance Metrics for Intelligent Systems - PerMIS '08, 2008Co-Authors: Edward TunstelAbstract:Robotic systems will perform mobile surveys for scientific and engineering purposes as part of future missions on lunar and Planetary Surfaces. With site characterization as a task objective various system configurations and surveying techniques are possible. This paper describes several examples of mobile surveying approaches using local and remote sensing configurations. A geometric measure of are a coverage performance is applied to each and relative performance in surveying a common area is characterized by expected performance trends. Performance metrics that solely express geometric aspects of the task are limited in utility as decision aids to mission operators. As such, the importance of enriching such metrics by incorporating additional attributes germane to surveying on Planetary Surfaces is highlighted.
