A5000546860- Planetary Science and Exploration
- Astro and Planetary Science
- Space Exploration and Technology
- Geology and Paleoclimatology Research
- Aeolian processes and effects
- Space Science and Extraterrestrial Life
- Methane Hydrates and Related Phenomena
- Geophysical Methods and Applications
- Atmospheric and Environmental Gas Dynamics
- Geological and Geochemical Analysis
- Landslides and related hazards
- Marine and environmental studies
- Spaceflight effects on biology
- Remote Sensing and LiDAR Applications
- Geochemistry and Geologic Mapping
- Cryospheric studies and observations
- Atmospheric Ozone and Climate
- earthquake and tectonic studies
- Seismic Waves and Analysis
- Paleontology and Stratigraphy of Fossils
- Spacecraft and Cryogenic Technologies
- 3D Surveying and Cultural Heritage
- Seismic Imaging and Inversion Techniques
- Geological Modeling and Analysis
- Space Satellite Systems and Control
Goddard Space Flight Center
2014-2025
University of Maryland, College Park
2016-2025
National Aeronautics and Space Administration
2022
International Space Station
2021
Idaho State University
2021
University at Buffalo, State University of New York
2008-2017
Universities Space Research Association
2017
Deleted Institution
2017
Earth Observatory of Singapore
2013-2015
Nanyang Technological University
2013-2015
The ripple field known as “El Dorado” was a unique stop on Spirit's traverse where dust‐raising, active mafic sand ripples and larger inactive coarse‐grained interact, illuminating several long‐standing issues of Martian dust mobility, the origin transverse aeolian ridges. Strong regional wind events endured by Spirit caused perceptible migration crests in deposits SSE El Dorado, erasure tracks sandy areas, changes to mantling site. Localized thermal vortices swept across leaving paths...
A visible atmospheric optical depth of 0.9 was measured by the Spirit rover at Gusev crater and Opportunity Meridiani Planum. Optical decreased about 0.6 to 0.7% per sol through both 90-sol primary missions. The vertical distribution dust consistent with uniform mixing, a scale height 11.56 +/- 0.62 kilometers. dust's cross section weighted mean radius 1.47 0.21 micrometers (mm) 1.52 0.18 mm Meridiani. Comparison depths 9-mm shows visible-to-infrared ratio 2.0 0.2 for comparison previous...
A full dust devil “season” was observed from Spirit 10 March 2005 (sol 421, first active observed) to 12 December 691, last seen); this corresponds the period L s 173.2° 339.5°, or southern spring and summer on Mars. Thermal Emission Spectrometer data suggest a correlation between high surface temperatures positive thermal gradient with devils in Gusev that landed waning stages of season as decreased. 533 were observed, enabling new characterizations; they ranged diameter 2 276 m, most range...
Wind‐related features observed by the rover Spirit in Gusev crater, Mars, include patches of soil on surface, some which are organized into bed forms. Windblown grains dust (inferred to be <3 μm diameter), sands (up a few hundred and granules (>2 mm diameter). Microscopic Imager data show rounded relatively spherical, typical transported long distances wind. The interior forms exposed operations suggests infiltration among grains, indicating that these not currently experiencing...
There are ~750 active and potentially volcanoes in Southeast Asia. Ash from eruptions of volcanic explosivity index 3 (VEI 3) smaller pose mostly local hazards while VEI ≥ 4 could disrupt trade, travel, daily life large parts the region. We classify Asian into five groups, using their morphology and, where known, eruptive history degassing style. Because histories most Asia poorly constrained, we assume that with similar morphologies have had eruption histories. Eruption well-studied...
The Microscopic Imager on the Opportunity rover analyzed textures of soils and rocks at Meridiani Planum a scale 31 micrometers per pixel. uppermost millimeter some is weakly cemented, whereas other show little evidence cohesion. Rock outcrops are laminated scale; image mosaics cross-stratification suggest that sediments were deposited by flowing water. Vugs in outcrop faces probably molds formed dissolution relatively soluble minerals during diagenesis. images support hypothesis...
Spirit began operations in Gusev Crater January 2004 and has returned data on three seasons of dust devil (DD) activity. Total DDs observed were 533 season one, 101 two, 127 three. Their general characteristics are the same within factors 2 among seasons, with median diameters 19 m 24 39 three, flux values for individual vortices ranging from 4.0 × 10 −9 to 4.6 −4 kg −2 s −1 5.2 −7 6.2 −5 1.5 1.6 All initiated onset southern Martian spring 14 sols L (181°) their frequency increased period...
Dust devils and dust devil tracks have been frequently observed in Viking Orbiter Mars Camera (MOC) images, but the parameters that control their distribution poorly constrained. Here we investigate abundance of two large study areas, Argyre Planitia Hellas Basin, using a survey over 3000 MOC narrow‐angle (NA) images. We report effect season, elevation, surface properties on track measurements density (the number per square kilometer). In both occur predominantly summer are rarely winter....
Wind-abraded rocks, ripples, drifts, and other deposits of windblown sediments are seen at the Columbia Memorial Station where Spirit rover landed. Orientations these features suggest formative winds from north-northwest, consistent with predictions atmospheric models afternoon in Gusev Crater. Cuttings Rock Abrasion Tool asymmetrically distributed toward south-southeast, suggesting active north-northwest time (midday) abrasion operations. Characteristics some such as a two-toned appearance,...
This paper presents the initial results of lander and rover localization topographic mapping MER 2003 mission (by Sol 225 for Spirit 206 Opportunity). The has traversed a distance 3.2 km (actual traveled instead odometry) Opportunity at 1.2 km. We localized landers in Gusev Crater on Meridiani Planum using two-way Doppler radio positioning technology cartographic triangulations through landmarks visible both orbital ground images. Additional high-resolution images were taken to verify...
Martian dust devil activity, inferred from their tracks, is mapped globally and compared to surface atmospheric properties. Dust devils are estimated lift 2.3 ± 1 × 10 11 kg of each year, mostly two narrow bands near 60°N 60°S, during respective spring summer. Approximately 55% the lifted by in northern hemisphere removed within 45 75°N, while 65% that south 75°S. The southern band an order magnitude more populated with tracks than north, likely a result Mars' orbital eccentricity. equator...
Linear, low‐albedo patterns (termed dark wind streaks) formed on the floor of Gusev crater between September 2003 and February 2004, as seen High Resolution Stereo Camera images taken board Mars Express Orbiter. Pancam from Exploration Rover Spirit show that rover crossed a streak during its traverse to Bonneville crater. Microscopic Imager data reveal sand grains within are relatively free dust, whereas outside mantled with dust. During 2004 solar conjunction, remained in one location sol...
Abundant wind‐related features occur along Spirit's traverse into the Columbia Hills over basaltic plains of Gusev Crater. Most windblown sands are probably derived from weathering rocks within crater, and possibly deposits associated with Ma'adim Vallis. Windblown particles act as agents abrasion, forming ventifacts, organized in places various bed forms. Wind‐related seen orbit, results atmospheric models, considerations topography suggest that general wind patterns transport pathways...
We use the Dyngjusandur sandsheet, Iceland, as a testbed to assess type and number of measurements required accurately represent ventifact orientations extract paleowind information through statistical evaluation differences between photogrammetric based in situ feature orientations. Forty representative ventifacts were selected for measurement, 20 which imaged analysis produce oriented scaled virtual 3D models. An additional set made on “synthetic” models allow assessment erosional...
Abstract Geophysical measurements, such as seismic experiments, are a key target for scientific activities on planetary surfaces. Dense spatial sampling of measurements is often desirable, and acquisition traditionally performed at regular intervals. However, achieving dense made difficult by obstacles operational constraints surface mission. Here, we present an application compressive sensing (CS) in the design surveys surfaces imaging shallow subsurface. This approach based more flexible,...
Statistical measures of patterns (textures) in surface roughness are used to quantitatively differentiate volcanic deposit facies on the Pumice Plain, northern flank Mount St. Helens (MSH). Surface values derived from a Light Detection and Ranging (LiDAR) point cloud collected 2004 fixed-wing airborne platform. Patterns characterized using co-occurrence texture statistics. Pristine-pyroclastic, reworked-pyroclastic, mudflow, boulder beds, eroded lava flows, braided streams, other units...
Abstract Several large paterae in Arabia Terra are suggested to be calderas that produced colossal explosive eruptions (i.e., supereruptions). If these features indeed calderas, dispersion modeling suggests extensive ash deposits should common throughout the region. However, such have not previously been linked with calderas. Here, we describe layered containing minerals both consistent and diagnostic of altered volcanic Terra. These include Al‐dominant as montmorillonite, imogolite,...
Abstract The earliest stages of volcanic vent degradation are rarely measured, leaving a gap in the knowledge that informs landform models cinder cones and other monogenetic structures. We documented initial 500-m-long spatter rampart at primary 2014–2015 Holuhraun eruption northern Iceland with high-resolution topographic change maps derived from terrestrial laser scanning (TLS) photogrammetric surveys using an unoccupied aircraft system (UAS). Topographic differencing shows total negative...
Unconsolidated pyroclastic flow deposits of the 1993 eruption Lascar Volcano, Chile, have, with time, become increasingly dissected by a network deeply penetrating fractures. The fracture comprises orthogonal sets decimeter-wide linear voids that form pseudo-polygonal grid visible on deposit surface. In this work, we combine shallow surface geophysical imaging tools remote sensing observations and direct field measurements to investigate these fractures their underlying causal mechanisms....