We report preliminary observations obtained from the NEAR Laser Rangefinder (NLR) and NEAR Multis... more We report preliminary observations obtained from the NEAR Laser Rangefinder (NLR) and NEAR Multispectral Imager (MSI) for approx. 300 craters seen on 433 Eros to address Eros crater formation and degradation processes. Additional information is contained in the original extended abstract.
ABSTRACT Results of LEND, LOLA, and Diviner multi-instrument data analysis to find minimal depth ... more ABSTRACT Results of LEND, LOLA, and Diviner multi-instrument data analysis to find minimal depth and low limit of hydrogen concentration in regolith will be presented.
Geologic mapping from 10 deg N to 5 deg S, 12 deg W to 5 deg E, using MDIM, MOLA, and MOC NA data... more Geologic mapping from 10 deg N to 5 deg S, 12 deg W to 5 deg E, using MDIM, MOLA, and MOC NA data show that the terrains consist of tilted and dissected Noachian cratered material that has been overlain with up to 800 m of widespread, layered deposits. These deposits, including the hematite unit mapped from TES, have been eroded by wind, exposing the overall stratigraphic sequence. Analyses of TES-based thermal inertia and albedo, together with MOLA-derived corrected pulse widths (CPW, corrected for regional tilt) for the study area show that several factors control remote sensing properties of the mapped units. First, high albedo and CPW, low thermal inertia surfaces dominate the northern portion, without much regard for local bedrock units. These trends are associated with the Arabia rise and are probably due to regional-scale enhanced net dust deposition rates relative to surrounding low-lands. Second, crater interiors have high thermal inertia and CPW values, with low to mixed a...
Initial Mars Orbiter Laser Altimeter (MOLA) data are providing a detailed characterization of the... more Initial Mars Orbiter Laser Altimeter (MOLA) data are providing a detailed characterization of the type of caldera structures that are observed on Mars. These data permit much more accurate determination of the structure and volumes of caldera structures. (AIAA)
Hematite-bearing deposits in the Terra Meridiani region of Mars constitute the top stratum of a p... more Hematite-bearing deposits in the Terra Meridiani region of Mars constitute the top stratum of a partially eroded layered complex that covers dissected Noachian-aged cratered terrain. The hematite unit consists of dark plains and dunes covering a bright substrate. This substrate is fully exposed beyond the borders of the hematite-bearing deposit and consists of polygonal ground separated by ridges or valleys, together with layered deposits that have been eroded into a variety of landforms. The complex is partially covered by a regional-scale aeolian mantle that thickens toward the north. The hematite-bearing stratum exhibits low albedoes, pulse widths, and intermediate thermal inertias, whereas the underlying unit exhibits high values of these parameters. Both units have spectral emissivity signatures similar to those for the low albedo cratered terrain to the south, with the addition of hematite for the top stratum. The complex is interpreted to consist of extensive plains-forming lava flows and tephra deposits emplaced during an extensional regime and at least partially buried by an aeolian mantle. Aeolian stripping of the mantle exposed much of the complex and differentially eroded the deposits to produce the landforms existent today. Exploration of the hematite-bearing deposits by the 2003 Mars Exploration Rover, ''Opportunity,'' will allow testing of the hypotheses presented since this stratum has been locally reworked into dunes that only partially cover the underlying brighter portion of the complex. In particular, the rover-based measurements will allow us to test the extent to which the unusual remote-sensing properties of the units indicate aqueous alteration.
Submarine volcanism in shallow waters (<100 m), particularly in remote settings, is difficult ... more Submarine volcanism in shallow waters (<100 m), particularly in remote settings, is difficult to monitor quantitatively and, in the rare formation of islands, it is challenging to understand the rapid-paced erosion. However, these newly erupted volcanic islands become observable to airborne and/or satellite remote sensing instruments. NASA’s ICESat-2 satellite laser altimeter, combined with visible imagery (optical and microwave), provide a novel method of evaluating the elevation characteristics of newly emerged volcanoes and their subaerial eruption products. Niijima Fukutoku-Okanoba (NFO) is a submarine volcano 1300 km south of Tokyo (Ogasawara Archipelago of Japan) that periodically breaches the ocean surface to create new islands that are subsequently eroded. The recent eruption in August 2021 is a rare opportunity to investigate this island evolution using high-resolution satellite datasets with geodetic-quality ICESat-2 altimetry. Lansdat-8 and Planet imagery provide a qua...
Introduction: Venus is our nearest neighbor and the closest in size to our home planet. Yet it re... more Introduction: Venus is our nearest neighbor and the closest in size to our home planet. Yet it remains largely unexplored, its runaway greenhouse atmosphere remains unexplained and it’s geologic past unknown. The deep atmosphere of Venus remains largely unexplored and key details of its trace gas chemistry remain unmeasured. The history of key volatile reservoirs and surfaceatmosphere-interior exchange processes is poorly established and based on limited data. Noble gases within the bulk Venus atmosphere, as well as isotopes of hydrogen, oxygen, and sulfur, are essentially unmeasured to the degree required to address fundamental questions about the evolution of the planet. The planet that is the most capable of teaching us about our own planet must not remain so mysterious. The gaps in deep atmosphere and surface ground truth must be closed. The value of past and future remote sensing at Venus is threatened by our lack of in-situ data and unanswered fundamental questions about the a...
The Lunar Reconnaissance Orbiter's (LRO), Lunar Exploration Neutron Detector (LEND) was devel... more The Lunar Reconnaissance Orbiter's (LRO), Lunar Exploration Neutron Detector (LEND) was developed to refine the lunar surface hydrogen (H) measurements generated by the Lunar Prospector Neutron Spectrometer. LPNS measurements indicated a approx.4,6% decrease in polar epithermal fluxes equivalent to (1.5+/-0,8)% H concentration and are direct geochemical evidence indicating water /high H at the poles. Given the similar operational and instrumental objectives of the LEND and LPNS systems, an important science analysis step for LEND is to test correlation with existing research including LPNS measurements. In this analysis, we compare corrected low altitude epithermal rate data from LPNS available via NASA's Planetary Data System (PDS) with calibrated LEND epithermal maps using a cross-correlation technique
Recently, an airborne lidar system that measures laser pulse time-of-flight and the distortion of... more Recently, an airborne lidar system that measures laser pulse time-of-flight and the distortion of the pulse waveform upon reflection from earth surface terrain features was developed and is now operational. This instrument is combined with Global Positioning System (GPS) receivers and a two-axis gyroscope for accurate recovery of aircraft position and pointing attitude. The laser altimeter system is mounted on a high-altitude aircraft platform and operated in a repetitively-pulsed mode for measurements of surface elevation profiles at nadir. The laser transmitter makes use of recently developed short-pulse diode-pumped solid-state laser technology in Q-switched Nd:YAG operating at its fundamental wavelength of 1064 nm. A reflector telescope and silicon avalanche photodiode are the basis of the optical receiver. A high-speed time-interval unit and a separate high-bandwidth waveform digitizer under microcomputer control are used to process the backscattered pulses for measurements of ...
Investigation of lava flow deposits is a key component of Investigation II.A.1 in the VEXAG Goals... more Investigation of lava flow deposits is a key component of Investigation II.A.1 in the VEXAG Goals, Objectives and Investigations. Because much of the Venus surface is covered in lava flows, characterization of lava flow emplacement conditions(eruption rate and eruption duration) is critical for understanding the mechanisms through which magma is stored and released onto the surface as well as for placing constraints on rates of volcanic resurfacing throughout the geologic record preserved at the surface.
We report preliminary observations obtained from the NEAR Laser Rangefinder (NLR) and NEAR Multis... more We report preliminary observations obtained from the NEAR Laser Rangefinder (NLR) and NEAR Multispectral Imager (MSI) for approx. 300 craters seen on 433 Eros to address Eros crater formation and degradation processes. Additional information is contained in the original extended abstract.
ABSTRACT Results of LEND, LOLA, and Diviner multi-instrument data analysis to find minimal depth ... more ABSTRACT Results of LEND, LOLA, and Diviner multi-instrument data analysis to find minimal depth and low limit of hydrogen concentration in regolith will be presented.
Geologic mapping from 10 deg N to 5 deg S, 12 deg W to 5 deg E, using MDIM, MOLA, and MOC NA data... more Geologic mapping from 10 deg N to 5 deg S, 12 deg W to 5 deg E, using MDIM, MOLA, and MOC NA data show that the terrains consist of tilted and dissected Noachian cratered material that has been overlain with up to 800 m of widespread, layered deposits. These deposits, including the hematite unit mapped from TES, have been eroded by wind, exposing the overall stratigraphic sequence. Analyses of TES-based thermal inertia and albedo, together with MOLA-derived corrected pulse widths (CPW, corrected for regional tilt) for the study area show that several factors control remote sensing properties of the mapped units. First, high albedo and CPW, low thermal inertia surfaces dominate the northern portion, without much regard for local bedrock units. These trends are associated with the Arabia rise and are probably due to regional-scale enhanced net dust deposition rates relative to surrounding low-lands. Second, crater interiors have high thermal inertia and CPW values, with low to mixed a...
Initial Mars Orbiter Laser Altimeter (MOLA) data are providing a detailed characterization of the... more Initial Mars Orbiter Laser Altimeter (MOLA) data are providing a detailed characterization of the type of caldera structures that are observed on Mars. These data permit much more accurate determination of the structure and volumes of caldera structures. (AIAA)
Hematite-bearing deposits in the Terra Meridiani region of Mars constitute the top stratum of a p... more Hematite-bearing deposits in the Terra Meridiani region of Mars constitute the top stratum of a partially eroded layered complex that covers dissected Noachian-aged cratered terrain. The hematite unit consists of dark plains and dunes covering a bright substrate. This substrate is fully exposed beyond the borders of the hematite-bearing deposit and consists of polygonal ground separated by ridges or valleys, together with layered deposits that have been eroded into a variety of landforms. The complex is partially covered by a regional-scale aeolian mantle that thickens toward the north. The hematite-bearing stratum exhibits low albedoes, pulse widths, and intermediate thermal inertias, whereas the underlying unit exhibits high values of these parameters. Both units have spectral emissivity signatures similar to those for the low albedo cratered terrain to the south, with the addition of hematite for the top stratum. The complex is interpreted to consist of extensive plains-forming lava flows and tephra deposits emplaced during an extensional regime and at least partially buried by an aeolian mantle. Aeolian stripping of the mantle exposed much of the complex and differentially eroded the deposits to produce the landforms existent today. Exploration of the hematite-bearing deposits by the 2003 Mars Exploration Rover, ''Opportunity,'' will allow testing of the hypotheses presented since this stratum has been locally reworked into dunes that only partially cover the underlying brighter portion of the complex. In particular, the rover-based measurements will allow us to test the extent to which the unusual remote-sensing properties of the units indicate aqueous alteration.
Submarine volcanism in shallow waters (<100 m), particularly in remote settings, is difficult ... more Submarine volcanism in shallow waters (<100 m), particularly in remote settings, is difficult to monitor quantitatively and, in the rare formation of islands, it is challenging to understand the rapid-paced erosion. However, these newly erupted volcanic islands become observable to airborne and/or satellite remote sensing instruments. NASA’s ICESat-2 satellite laser altimeter, combined with visible imagery (optical and microwave), provide a novel method of evaluating the elevation characteristics of newly emerged volcanoes and their subaerial eruption products. Niijima Fukutoku-Okanoba (NFO) is a submarine volcano 1300 km south of Tokyo (Ogasawara Archipelago of Japan) that periodically breaches the ocean surface to create new islands that are subsequently eroded. The recent eruption in August 2021 is a rare opportunity to investigate this island evolution using high-resolution satellite datasets with geodetic-quality ICESat-2 altimetry. Lansdat-8 and Planet imagery provide a qua...
Introduction: Venus is our nearest neighbor and the closest in size to our home planet. Yet it re... more Introduction: Venus is our nearest neighbor and the closest in size to our home planet. Yet it remains largely unexplored, its runaway greenhouse atmosphere remains unexplained and it’s geologic past unknown. The deep atmosphere of Venus remains largely unexplored and key details of its trace gas chemistry remain unmeasured. The history of key volatile reservoirs and surfaceatmosphere-interior exchange processes is poorly established and based on limited data. Noble gases within the bulk Venus atmosphere, as well as isotopes of hydrogen, oxygen, and sulfur, are essentially unmeasured to the degree required to address fundamental questions about the evolution of the planet. The planet that is the most capable of teaching us about our own planet must not remain so mysterious. The gaps in deep atmosphere and surface ground truth must be closed. The value of past and future remote sensing at Venus is threatened by our lack of in-situ data and unanswered fundamental questions about the a...
The Lunar Reconnaissance Orbiter's (LRO), Lunar Exploration Neutron Detector (LEND) was devel... more The Lunar Reconnaissance Orbiter's (LRO), Lunar Exploration Neutron Detector (LEND) was developed to refine the lunar surface hydrogen (H) measurements generated by the Lunar Prospector Neutron Spectrometer. LPNS measurements indicated a approx.4,6% decrease in polar epithermal fluxes equivalent to (1.5+/-0,8)% H concentration and are direct geochemical evidence indicating water /high H at the poles. Given the similar operational and instrumental objectives of the LEND and LPNS systems, an important science analysis step for LEND is to test correlation with existing research including LPNS measurements. In this analysis, we compare corrected low altitude epithermal rate data from LPNS available via NASA's Planetary Data System (PDS) with calibrated LEND epithermal maps using a cross-correlation technique
Recently, an airborne lidar system that measures laser pulse time-of-flight and the distortion of... more Recently, an airborne lidar system that measures laser pulse time-of-flight and the distortion of the pulse waveform upon reflection from earth surface terrain features was developed and is now operational. This instrument is combined with Global Positioning System (GPS) receivers and a two-axis gyroscope for accurate recovery of aircraft position and pointing attitude. The laser altimeter system is mounted on a high-altitude aircraft platform and operated in a repetitively-pulsed mode for measurements of surface elevation profiles at nadir. The laser transmitter makes use of recently developed short-pulse diode-pumped solid-state laser technology in Q-switched Nd:YAG operating at its fundamental wavelength of 1064 nm. A reflector telescope and silicon avalanche photodiode are the basis of the optical receiver. A high-speed time-interval unit and a separate high-bandwidth waveform digitizer under microcomputer control are used to process the backscattered pulses for measurements of ...
Investigation of lava flow deposits is a key component of Investigation II.A.1 in the VEXAG Goals... more Investigation of lava flow deposits is a key component of Investigation II.A.1 in the VEXAG Goals, Objectives and Investigations. Because much of the Venus surface is covered in lava flows, characterization of lava flow emplacement conditions(eruption rate and eruption duration) is critical for understanding the mechanisms through which magma is stored and released onto the surface as well as for placing constraints on rates of volcanic resurfacing throughout the geologic record preserved at the surface.
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Papers by James Garvin