J. F. Bell
A5013004995- Planetary Science and Exploration
- Astro and Planetary Science
- Space Exploration and Technology
- Geology and Paleoclimatology Research
- Space Science and Extraterrestrial Life
- Geochemistry and Geologic Mapping
- Isotope Analysis in Ecology
- Spaceflight effects on biology
- Geological and Geochemical Analysis
- Paleontology and Stratigraphy of Fossils
- Aeolian processes and effects
- Marine and environmental studies
- Space exploration and regulation
- Hydrocarbon exploration and reservoir analysis
- Spacecraft and Cryogenic Technologies
- Atmospheric and Environmental Gas Dynamics
- Calibration and Measurement Techniques
- Stellar, planetary, and galactic studies
- Space Satellite Systems and Control
- Scientific Research and Discoveries
- Methane Hydrates and Related Phenomena
- Spacecraft Design and Technology
- Laser-induced spectroscopy and plasma
- Anomaly Detection Techniques and Applications
- Asian Geopolitics and Ethnography
Arizona State University
2016-2025
Jet Propulsion Laboratory
2003-2022
National Air and Space Museum
2022
Observatoire de Paris
2022
Earth and Space Research
2020
Physical Sciences (United States)
2013
Cornell University
2003-2012
Planetary Society
2012
Oberlin College
2007
Washington University in St. Louis
2004-2006
The Context Camera (CTX) on the Mars Reconnaissance Orbiter (MRO) is a Facility Instrument (i.e., government‐furnished equipment operated by science team not responsible for design and fabrication) designed, built, Malin Space Science Systems MRO Color Imager (MARCI). CTX will (1) provide context images data acquired other instruments, (2) observe features of interest to NASA's Exploration Program (e.g., candidate landing sites), (3) conduct scientific investigation, led MARCI team,...
Sedimentary rocks at Eagle crater in Meridiani Planum are composed of fine-grained siliciclastic materials derived from weathering basaltic rocks, sulfate minerals (including magnesium and jarosite) that constitute several tens percent the rock by weight, hematite. Cross-stratification observed outcrops indicates eolian aqueous transport. Diagenetic features include hematite-rich concretions crystal-mold vugs. We interpret to be a mixture chemical sediments with complex diagenetic history....
The Curiosity rover discovered fine-grained sedimentary rocks, which are inferred to represent an ancient lake and preserve evidence of environment that would have been suited support a martian biosphere founded on chemolithoautotrophy. This aqueous was characterized by neutral pH, low salinity, variable redox states both iron sulfur species. Carbon, hydrogen, oxygen, sulfur, nitrogen, phosphorus were measured directly as key biogenic elements; inference, is assumed available. probably had...
Spirit landed on the floor of Gusev Crater and conducted initial operations soil‐covered, rock‐strewn cratered plains underlain by olivine‐bearing basalts. Plains surface rocks are covered wind‐blown dust show evidence for enrichment soluble species as vein void‐filling materials coatings. The is result a minor amount transport deposition aqueous processes. Layered granular deposits were discovered in Columbia Hills, with outcrops that tend to dip conformably topography. interpreted be...
Sedimentary rocks at Yellowknife Bay (Gale crater) on Mars include mudstone sampled by the Curiosity rover. The samples, John Klein and Cumberland, contain detrital basaltic minerals, calcium sulfates, iron oxide or hydroxides, sulfides, amorphous material, trioctahedral smectites. smectite has basal spacing of ~10 angstroms, indicating little interlayer hydration. Cumberland both ~13.2 angstroms. larger suggests a partially chloritized magnesium facilitating H2O retention. Basaltic minerals...
The Radiation Assessment Detector (RAD) on the Mars Science Laboratory’s Curiosity rover began making detailed measurements of cosmic ray and energetic particle radiation environment surface 7 August 2012. We report discuss absorbed dose equivalent from galactic rays solar particles martian for ~300 days observations during current maximum. These provide insight into hazards associated with a human mission to an anchor point which model subsurface environment, implications microbial survival...
The Mars Exploration Rover Opportunity has investigated the landing site in Eagle crater and nearby plains within Meridiani Planum. soils consist of fine-grained basaltic sand a surface lag hematite-rich spherules, spherule fragments, other granules. Wind ripples are common. Underlying thin soil layer, exposed small impact craters troughs, flat-lying sedimentary rocks. These rocks finely laminated, rich sulfur, contain abundant sulfate salts. Small-scale cross-lamination some locations...
The ChemCam instrument suite on the Mars Science Laboratory (MSL) rover Curiosity provides remote compositional information using first laser-induced breakdown spectrometer (LIBS) a planetary mission, and sample texture morphology data micro-imager (RMI). Overall, supports MSL with five capabilities: classification of rock soil characteristics; quantitative elemental compositions including light elements like hydrogen some to which LIBS is uniquely sensitive (e.g., Li, Be, Rb, Sr, Ba);...
The Mars Exploration Rover Spirit and its Athena science payload have been used to investigate a landing site in Gusev crater. is hypothesized be the of former lake, but no clear evidence for lacustrine sedimentation has found date. Instead, dominant lithology basalt, geologic processes are impact events eolian transport. Many rocks exhibit coatings other characteristics that may minor aqueous alteration. Any sediments exist at this location within apparently buried by lavas undergone...
Samples from the Rocknest aeolian deposit were heated to ~835°C under helium flow and evolved gases analyzed by Curiosity’s Sample Analysis at Mars instrument suite. H 2 O, SO , CO O major released. Water abundance (1.5 3 weight percent) release temperature suggest that is bound within an amorphous component of sample. Decomposition fine-grained Fe or Mg carbonate likely source much . Evolved coincident with Cl, suggesting oxygen produced thermal decomposition oxychloride compound. Elevated...
The Thermal Emission Imaging System (THEMIS) on Mars Odyssey has produced infrared to visible wavelength images of the martian surface that show lithologically distinct layers with variable thickness, implying temporal changes in processes or environments during after their formation. Kilometer-scale exposures bedrock are observed; elsewhere airfall dust completely mantles over thousands square kilometers. compositional variations at 100-meter scales, for example, an exposure olivine-rich...
Volume mixing and isotope ratios secured with repeated atmospheric measurements taken the Sample Analysis at Mars instrument suite on Curiosity rover are: carbon dioxide (CO2), 0.960(±0.007); argon-40 ((40)Ar), 0.0193(±0.0001); nitrogen (N2), 0.0189(±0.0003); oxygen, 1.45(±0.09) × 10(-3); monoxide, < 1.0 (40)Ar/(36)Ar, 1.9(±0.3) 10(3). The (40)Ar/N2 ratio is 1.7 times greater (40)Ar/(36)Ar 1.6 lower than values reported by Viking Lander mass spectrometer in 1976, whereas other are generally...
H 2 O, CO , SO O S, HCl, chlorinated hydrocarbons, NO, and other trace gases were evolved during pyrolysis of two mudstone samples acquired by the Curiosity rover at Yellowknife Bay within Gale crater, Mars. O/OH-bearing phases included 2:1 phyllosilicate(s), bassanite, akaganeite, amorphous materials. Thermal decomposition carbonates combustion organic materials are candidate sources for . Concurrent evolution hydrocarbons suggests presence oxychlorine phase(s). Sulfides likely...
Observations by the Mars Science Laboratory Mast Camera (Mastcam) in Gale crater reveal isolated outcrops of cemented pebbles (2 to 40 millimeters diameter) and sand grains with textures typical fluvial sedimentary conglomerates. Rounded conglomerates indicate substantial abrasion. ChemCam emission spectra at one outcrop show a predominantly feldspathic composition, consistent minimal aqueous alteration sediments. Sediment was mobilized ancient water flows that likely exceeded threshold...
The Rocknest aeolian deposit is similar to features analyzed by the Mars Exploration Rovers (MERs) Spirit and Opportunity. fraction of sand <150 micrometers in size contains ~55% crystalline material consistent with a basaltic heritage ~45% x-ray amorphous material. component iron-rich silicon-poor host volatiles (water, oxygen, sulfur dioxide, carbon chlorine) detected Sample Analysis at instrument fine-grained nanophase oxide first described from soils MERs. similarity between materials...
The Microscopic Imager (MI) on the Mars Exploration Rover Opportunity has returned images of with higher resolution than any previous camera system, allowing detailed petrographic and sedimentological studies rocks soils at Meridiani Planum landing site. Designed to simulate a geologist's hand lens, MI is mounted Opportunity's instrument arm can resolve objects 0.1 mm across or larger. This paper provides an overview operations, data calibration, analysis during first 900 sols (Mars days)...
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...
Sedimentary rocks examined by the Curiosity rover at Yellowknife Bay, Mars, were derived from sources that evolved an approximately average martian crustal composition to one influenced alkaline basalts. No evidence of chemical weathering is preserved, indicating arid, possibly cold, paleoclimates and rapid erosion deposition. The absence predicted geochemical variations indicates magnetite phyllosilicates formed diagenesis under low-temperature, circumneutral pH, rock-dominated aqueous...
Dedication Acknowledgements Foreword Part I. Introduction and Historical Perspective: 1. Exploration of the Martian surface: 1992-2007 2. context: pre-MGS view Mars' surface composition II. Elemental Composition: Orbital In Situ Surface Measurements: A. Results Interpretations from New APXS 3. chemistry: results Pathfinder landing site 4. Mars exploration rovers - chemical by B. 5. abundances determined via Odyssey GRS 6. Volatiles on Mars: scientific Neutron Spectrometer III. Mineralogy...
The ChemCam instrument, which provides insight into martian soil chemistry at the submillimeter scale, identified two principal types along Curiosity rover traverse: a fine-grained mafic type and locally derived, coarse-grained felsic type. component is representative of widespread soils similar in composition to dust. It possesses ubiquitous hydrogen signature spectra, corresponding hydration amorphous phases found by CheMin instrument. This likely accounts for an important fraction global...
Abstract The Curiosity rover has analyzed abundant light‐toned fracture‐fill material within the Yellowknife Bay sedimentary deposits. ChemCam instrument, coupled with Mastcam and ChemCam/Remote Micro Imager images, was able to demonstrate that these fracture fills consist of calcium sulfate veins, many which appear be hydrated at a level expected for gypsum bassanite. Anhydrite is locally present found in location characterized by nodular texture. An intricate assemblage veins crosses...