A5030492178- Astro and Planetary Science
- Planetary Science and Exploration
- Isotope Analysis in Ecology
- Spacecraft and Cryogenic Technologies
- Astrophysics and Star Formation Studies
- High-pressure geophysics and materials
- Nuclear Physics and Applications
- Space Exploration and Technology
- Mass Spectrometry Techniques and Applications
- Stellar, planetary, and galactic studies
- Gamma-ray bursts and supernovae
- Laser-induced spectroscopy and plasma
- Geological and Geochemical Analysis
- Space exploration and regulation
- Geology and Paleoclimatology Research
- Atmospheric Ozone and Climate
- Solar and Space Plasma Dynamics
- Spaceflight effects on biology
- Geomagnetism and Paleomagnetism Studies
- Spacecraft Design and Technology
- Methane Hydrates and Related Phenomena
- Marine and environmental studies
- Paleontology and Stratigraphy of Fossils
- Fluid Dynamics Simulations and Interactions
- Molecular Spectroscopy and Structure
Johnson Space Center
2014-2023
Universitat de València
2018
Jacobs (United States)
2006-2013
University of Washington
2006
Lawrence Livermore National Laboratory
2006
Osservatorio Astrofisico di Catania
2006
National Institute for Astrophysics
2006
United States Naval Research Laboratory
2006
Brookhaven National Laboratory
2006
Institut d'Astrophysique Spatiale
2006
The bulk of the comet 81P/Wild 2 (hereafter Wild 2) samples returned to Earth by Stardust spacecraft appear be weakly constructed mixtures nanometer-scale grains, with occasional much larger (over 1 micrometer) ferromagnesian silicates, Fe-Ni sulfides, metal, and accessory phases. very wide range olivine low-Ca pyroxene compositions in requires a formation conditions, probably reflecting different locations protoplanetary disk. restricted compositional ranges for absence hydrous phases...
Hydrogen, carbon, nitrogen, and oxygen isotopic compositions are heterogeneous among comet 81P/Wild 2 particle fragments; however, extreme anomalies rare, indicating that the is not a pristine aggregate of presolar materials. Nonterrestrial nitrogen neon isotope ratios suggest indigenous organic matter highly volatile materials were successfully collected. Except for single 17 O-enriched circumstellar stardust grain, silicate oxide minerals have consistent with solar system origin. One...
The Hayabusa2 spacecraft investigated the C-type (carbonaceous) asteroid (162173) Ryugu. mission performed two landing operations to collect samples of surface and subsurface material, latter exposed by an artificial impact. We present images second touchdown site, finding that ejecta from impact crater was at sample location. Surface pebbles both sites show morphological variations ranging rugged smooth, similar Ryugu's boulders, shapes quasi-spherical flattened. were returned Earth on 6...
Coordinated transmission electron microscopy and isotopic measurements of organic globules in the Tagish Lake meteorite shows that they have elevated ratios nitrogen-15 to nitrogen-14 (1.2 2 times terrestrial) deuterium hydrogen (2.5 9 terrestrial). These anomalies are indicative mass fractionation during chemical reactions at extremely low temperatures (10 20 kelvin), characteristic cold molecular clouds outer protosolar disk. The probably originated as ice coatings on preexisting grains...
We measured the elemental compositions of material from 23 particles in aerogel and residue seven craters aluminum foil that was collected during passage Stardust spacecraft through coma comet 81P/Wild 2. These are chemically heterogeneous at largest size scale analyzed (â¼180 ng). The mean composition this Wild 2 is consistent with CI meteorite composition, which thought to represent bulk solar system, for elements Mg, Si, Mn, Fe, Ni 35%, Ca Ti 60%. Cu, Zn, Ga appear enriched material,...
Infrared spectra of material captured from comet 81P/Wild 2 by the Stardust spacecraft reveal indigenous aliphatic hydrocarbons similar to those in interplanetary dust particles thought be derived comets, but with longer chain lengths than observed diffuse interstellar medium. Similarly, samples contain abundant amorphous silicates addition crystalline such as olivine and pyroxene. The presence Wild is consistent mixing solar system matter. No hydrous or carbonate minerals were detected,...
Abstract— We compare the observed composition ranges of olivine, pyroxene, and Fe‐Ni sulfides in Wild 2 grains with those from chondritic interplanetary dust particles (IDPs) chondrite classes to explore whether these data suggest affinities known hydrous materials particular. olivine has an extremely wide range, Fa 0–96 , a pronounced frequency peak at 1 . The range displayed by low‐calcium pyroxene is also very extensive, Fs 48 0 significant centered 5 These are as broad or broader than...
Abstract Three masses of the Chelyabinsk meteorite have been studied with a wide range analytical techniques to understand mineralogical variation and thermal history parent body. The samples exhibit little no postentry oxidation via Mössbauer Raman spectroscopy indicating their fresh character, but despite rapid collection care handling some low levels terrestrial contamination did nonetheless result. Detailed studies show three distinct lithologies, indicative genomict breccia. A...
Abstract– Recent spacecraft missions to comets have reopened a long‐standing debate about the histories and origins of cometary materials. Comets contain mixtures anhydrous minerals ices seemingly unaffected by planetary processes, yet there are indications hydrated silicate component. We performed aqueous alteration experiments on interplanetary dust particles (IDPs) that likely derived from comets. Hydrated silicates rapidly formed submicrometer amorphous within IDPs at room temperature in...
Abstract– The successful return of the Stardust spacecraft provides a unique opportunity to investigate nature and distribution organic matter in cometary dust particles collected from comet 81P/Wild 2. Analysis individual impact tracks silica aerogel using technique two‐step laser mass spectrometry demonstrates presence complex aromatic matter. While concerns remain as purity collection medium thermal effects associated with hypervelocity capture, majority observed species appear indigenous...
Wassonite, ideally stoichiometric TiS, is a titanium monosulfide not previously observed in nature, that was discovered within the Yamato 691 EH3 enstatite chondrite. Twelve Ti-S phase grains were identified rare barred olivine (BO) chondrule; three of extracted by focused ion beam technique. Because submicrometer size wassonite grains, it possible to determine conventional macroscopic properties. However, chemical composition and crystal structure well constrained extensive quantitative...
Abstract NASA's OSIRIS‐REx spacecraft collected samples from carbonaceous near‐Earth asteroid (101955) Bennu on October 20, 2020, and will deliver them to the Earth September 24, 2023. The be processed at NASA Johnson Space Center (JSC), where most of sample collection subsequently curated in a new cleanroom suite. loose regolith two ways: bulk chamber capable holding up 2 kg, industrial Velcro “contact pads” intended collect small particles surface. Included JSC sample, contact pads,...
Brownleeite, ideally stoichiometric MnSi, is a manganese silicide not previously observed in nature that was discovered within an interplanetary dust particle likely originated from comet. Three submicrometer brownleeite grains were found, with one of them poikilitically enclosed by Mnbearing forsterite. Owing to the small size grains, it possible determine conventional macroscopic properties this mineral; however, chemical composition and crystal structure well constrained extensive...
Abstract— During preliminary examination of 81P/Wild 2 particles collected by the NASA Stardust spacecraft, we analyzed seven, sulfur embedded and ultramicrotomed extracted from five different tracks. Sections were using a scanning transmission X‐ray microscope (SXTM) carbon absorption near edge structure (XANES) spectra collected. We compared XANES these Wild samples with database on thirty‐four interplanetary dust (IDPs) several meteorites. Two are iron sulfides there is evidence that an...
Abstract– Distributions of organic functional groups as well inorganic features were analyzed in the Bells (CM2) carbonaceous chondrite using near‐field infrared (NFIR) spectroscopy. NFIR spectroscopy has recently been developed to enable spectral mapping beyond optical diffraction limit conventional Fourier transform microspectroscopy. 300 nm thick sections on Al plates for 7.5 × μm 2 areas showed some C‐H‐rich which considered represent organic‐rich areas. Heterogeneous distributions...
Abstract— Organic contamination (˜2965 and ˜1260 cm −1 peaks) was found on Tagish Lake (C2) Murchison (CM2) carbonaceous chondrites containing abundant hydrous minerals by Fourier transform infrared (FTIR) microspectroscopy the samples pressed Al plates. On other hand, anhydrous chondrite (Moss, CO3) not contaminated. This occurred within one day of storage, when were stored containers including silicone rubber mats. Volatile molecules having similar peaks to contaminants detected long‐path...
Abstract– We have developed new sample preparation and analytical techniques tailored for entire aerogel tracks of Wild 2 analyses both on “carrot” “bulbous” tracks. successfully ultramicrotomed an track along its axis while preserving original shape. This innovation allowed us to examine the distribution fragments from entrance hole all way terminal particle. The crystalline silicates we measured Mg‐rich compositions O isotopic in range meteoritic materials, implying that they originated...
Abstract— Micrometeorites have been significantly altered or melted by heating, which has mainly ascribed to aerodynamic drag during atmospheric entry. However, if a major fraction of micrometeorites are produced impacts on porous asteroids, they may experienced shock heating before contact with the Earth's atmosphere (Tomeoka et al. 2003). A transmission electron microscope (TEM) study matrix Murchison CM chondrite experimentally shocked at pressures 10–49 GPa shows that its mineralogy and...
Aims. We attempt to ellucidate the structure and chemical composition of carbon bulk detected in cometary Stardust particles. determine if material observed spectroscopically is true origin whether or not it was formed by direct UV-photoprocessing icy grain mantles local dense cloud and/or solar nebula.
Abstract— We conducted impact experiments into SiO 2 ‐based aerogel of uniform density (0.02 g cm −3 ) with spherical corundum projectiles. The highly refractory nature and mechanical strength minimizes projectile deformation continuous mass loss by ablation that might have affected earlier soda‐lime glass (SLG) impactors targets. find is a vastly superior penetrator producing tracks factor 2.5 longer, yet similar in diameter to those made SLG. At velocities <4 km s −1 cylindrical...
Abstract We performed chemical, mineralogical, and isotopic studies of the first interplanetary dust particles (IDPs) collected in stratosphere without use silicone oil. The collection substrate, polyurethane foam, effectively traps impacting particles, but lack an embedding medium results significant particle fragmentation. Two found on collector exhibit typical compositional mineralogical properties chondritic porous (CP‐IDPs). Hydrogen nitrogen imaging revealed anomalies magnitude spatial...
Abstract— We describe briefly some of the challenges to Stardust mission, curation, and sample preliminary analysis from perspective Curation Office at Johnson Space Center. Our goal is inform persons planning future returns so that they may learn both our successes (and avoid mistakes). The played a role in mission its inception, most critically assisting design implementation spacecraft contamination control plan, documenting recovery re‐entry capsule Utah. A unique class 100 cleanroom was...
The Stardust spacecraft successfully returned dust from comet 81P/Wild 2 to Earth in January 2006. Preliminary examination of the samples showed abundant crystalline silicates comparable those found chondritic meteorites presumably formed asteroid belt. Here, we report results a transmission electron microscopy (TEM) study pyroxene-bearing terminal particle, which contains lamellar intergrowths pigeonite and diopside on (001) plane. This microstructure is typical for an igneous process...