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  • 1
    Publication Date: 2019-05-07
    Description: Review of space climatology is presented with a view toward spacecraft electronics applications. The origins and abundances of space radiations are discussed and related to their potential effects. Significant historical developments are summarized leading to the inception of space climatology and into the space era. Energetic particle radiation properties and models of galactic cosmic rays, solar energetic and geomagnetic trapped particles are described. This includes current radiation effects issues that models face today.
    Keywords: Space Sciences (General)
    Type: GSFC-E-DAA-TN61754 , IEEE Transactions on Nuclear Science (ISSN 0018-9499) (e-ISSN 1558-1578); 66; 1; 17-37
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  • 2
    Publication Date: 2019-05-25
    Description: Isomers with the formula C3H2O have intrigued and puzzled astronomers and astrochemists for many years, with propynal and cyclopropenone, but not propadienone, known to be interstellar. However, there is a severe lack of laboratory spectra of the solid phases of these compounds with which to investigate their interstellar chemistry. Here we present the first infrared spectra of amorphous and crystalline forms of propynal, HCCC(O)H, at multiple temperatures. Band positions are tabulated and band strengths are derived in terms of absorption coefficients and integrated intensities. Optical constants are calculated for amorphous propynal, refractive indices are measured, and densities are estimated. Three laboratory astrochemistry applications are described, including a new spectral identification in an earlier paper. It is shown that propynal's CC infrared absorbance is about 30 000 per cent stronger than the corresponding feature in acetylene. This band's intensity and spectral position make it an attractive candidate for astronomical searches involving interstellar ices.
    Keywords: Space Sciences (General)
    Type: GSFC-E-DAA-TN68651 , Monthly Notices of the Royal Astronomical Society (ISSN 0035-8711) (e-ISSN 1365-2966); 482; 3; 4009-4017
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  • 3
    Publication Date: 2019-07-19
    Description: NASA has an ongoing program of collecting interplanetary dust particles (IDPs) in the stratosphere using high altitude research aircraft. The collected IDPs are derived from asteroids and comets and here we report studies of a subset of hydrated IDPs rich in carbonaceous matter that are proposed to have a cometary origin. Our studies are aimed at understanding the evolution of oxygen reservoirs in the Solar System and their interaction with cometary minerals and organic matter. The small size (〈20 m) and fragility of these IDPs present a number of analytical challenges. We have pioneered techniques for performing chemical, mineralogical, isotopic, and spectroscopic measurements on the same sample in a carefully coordinated sequence. Coordinated analyses of nanogram-size samples is made possible by several delicate sample preparation techniques. To avoid organic contamination, we embed IDPs in elemental sulfur and use ultramicrotomy to partly section the particles (the first few micrometers). Multiple thin sections (50-70 nm thick) are placed on different substrates depending on the analysis technique. We use a JEOL 2500SE scanning, transmission electron microscope (STEM) to determine the mineralogy, microstructure, and elemental compositions of constituent minerals in the thin sections through a combination of high resolution imaging, electron diffraction, quantitative energy-dispersive x-ray mapping, and electron energy-loss spectroscopy. Following the STEM analyses, we use a NanoSIMS 50L for high spatial resolution isotopic measurements of H, C, N, and O to search for presolar grains and to understand the origin of the indigenous organic matter. The isotopic analyses are performed on the same sections analyzed in the STEM in order to correlate isotopic properties with the elemental and mineralogical data. We reserve other thin sections for non-destructive analyses utilizing synchrotron-based techniques including Fourier-transform infrared (FTIR) micro-spectroscopy and X-ray absorption near-edge structure (XANES) analyses, especially for functional group analysis of organic matter in the particles. The remainder of the IDP is extracted from the sulfur bead that was used for microtomy and is pressed into Au foil for quantitative analysis (including light elements) using a JEOL 8530F field emission electron probe microanalyzer (EPMA). After the EPMA measurements, high precision oxygen isotopic analyses are obtained using Cameca IMS1270/1290 instruments at UCLA. The hydrated IDPs in this study are dominated by saponitic clays, with minor magnetite, carbonate and abundant organic matter. The remarkable oxygen isotopic compositions, high carbon contents, and the abundance of isotopically anomalous organic matter, together suggest that the high carbon, hydrated IDPs are derived from primitive sources not yet represented in meteorite collections such as outer main belt P- and D-type asteroids or comets.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN54548 , Microscopy and Microanalysis 2018; Aug 05, 2018 - Aug 09, 2018; Baltimore, MD; United States
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  • 4
    Publication Date: 2019-07-19
    Description: We are using innovative FIB techniques to prepare samples of planetary materials for different types of coordinated analyses using ion microprobes, synchrotron beamlines, and specialized transmission electron microscopy (TEM) techniques. In these cases, the FIB sample preparation is the critical step in enabling these specialized analyses. We discuss several examples below utilizing the FEI Quanta3D instrument at the NASA Johnson Space Center. Trace element analyses utilizing synchrotron x-ray fluorescence. The trace element content of mineral grains in comet dust provides important clues on their formation and processing in the early solar system. We preformed coordinated analyses of a comet dust particle that had been prepared using ultramicrotomy for TEM analysis. Following the TEM analyses, we extracted a 70 nm thick section from a region of the carbon (C) film of the TEM grid, for additional analyses. A carbon ring ~2-3 m thick was deposited on top of the C film using the FIB. The C film on the outer rim of the ring was milled away using various patterns to uniformly release the stresses on the film, preventing rupture and collapse, and was attached to the micromanipulator needle. We then isolated the ring completely and transferred the section to a silicon sample holder for analysis using the HXN (hard X-ray nanoprobe) beamline at NSLSII at Brookhaven National Lab. Coordinated Analyses of Presolar Grains. Rare sub-m presolar grains that originate in evolved stars and supernovae, occur in primitive astromaterials and are identified by their exotic isotopic compositions. Coordinated analyses of these grains using NanoSIMS, TEM, and other techniques on the same grain is enabled by innovative FIB sample preparation. In order to obtain subsequent isotopic analyses of Mg and Fe, contributions from surrounding grains were minimized. We precisely deposited a protective cap of Pt on top of the grain to preserve the grain of interest and then milled away about 5 m diameter of the surrounding material. Following the isotopic analyses, the spindle was extracted and thinned to electron transparency for TEM microstructural analyses. In situ heating TEM experiments on lunar samples. We extracted a FIB thin section from Apollo 17 lunar rock 76015. To avoid ion-beam damage, e-beam deposition was used to deposit the first 500 nm of the C strap, followed by ion beam-assisted deposition of ~3 m carbon. We performed an ex situ lift-out of the section and placed the section on one of the elements of a microelectromechanical systems (MEMS) - specialized heating substrate and attached the section to the substrate by depositing small C straps with the FIB. The heating chips utilize silicon nitride windows to support the samples and provide uniform heating while enabling TEM imaging. The heating chip was loaded into a Hitachi Blaze heating holder and analyzed using a Hitachi HF5000 at the University of Arizona.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN54565 , Microscopy and Microanalysis 2018; Aug 05, 2018 - Aug 09, 2018; Baltimore, MD; United States
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  • 5
    Publication Date: 2019-07-19
    Description: Anomalously fractionated isotopic material is found in many primitive Solar System objects, such as meteorites and comets. It is thought, in some cases, to trace interstellar matter that was incorporated into the Solar Nebula without undergoing significant processing. We will review observations and models of the nitrogen, oxygen, and carbon fractionation chemistry in dense molecular clouds. The range of fractionation ratios expected in different interstellar molecules will be discussed and compared to the ratios measured in molecular clouds, comets and meteoritic material.These studies make several predictions that can be tested by high-resolution molecular line observations with ALMA (Atacama Large Millimeter Array).
    Keywords: Space Sciences (General)
    Type: GSFC-E-DAA-TN60285 , Scientific Collaboration Discussions; Sep 19, 2018; Gothenburg; Sweden
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  • 6
    Publication Date: 2019-07-19
    Description: Water-rich carbonaceous chondrites contain evidence of aqueous alteration in the early solar system. To see this one must look carefully at the meteorites, and see past the later alteration which has generally obscured mineral textures. We suggest that these materials will dominate, be detectable, and be sampled on the surfaces of C-class asteroids, initially by the Hayabusa2 spacecraft. Thus, hydrous samples returned by this mission will help to reveal the source of water on earth.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN51549 , Seminar at Plymouth University; Apr 12, 2018; Plymouth; United Kingdom
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  • 7
    Publication Date: 2019-07-12
    Description: The origins of Phobos and Deimos are uncertain; both are so space weathered that their surface compositions are difficult to determine using spectral reflectance measurements. We show how the winter temperatures and associated conditions in the polar regions of Phobos could make the regolith susceptible to space weathering from dielectric breakdown caused by solar energetic particles (SEPs). During SEP events, charged particles accumulate throughout the top ~ 1 mm of the regolith, which has low condukctivity, and create subsurface electric fields that act to dissipate any net buildup of charge. The faster the net charge accumulates, the larger the electric field needed to dissipate it. If the magnitude of the subsurface electric field exceeds ~10 6 V m -1, then dielectric breadkown is likely. This process rapidly dissipates the buildup of charge by vaporizing electrically conducting channels through the regolith. Dielectric breakdown
    Keywords: Space Sciences (General)
    Type: GSFC-E-DAA-TN54033 , Advances in Space Research
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  • 8
    Publication Date: 2019-07-12
    Description: The nature and origin of extraterrestrial organic matter are still under debate despite the significant progress in the analyses and experimental approaches in this field over the last five decades. Xenolithic clasts are often found in a wide variety of meteorite groups, some of which contain exotic organic matter (OM). The Zag meteorite is a thermally-metamorphosed H ordinary chondrite. It contains a primitive xenolithic clast that has been proposed to have originated from Ceres, which was accreted to the Zag host asteroid after metamorphism. The cm-sized clast contains abundant large carbon-rich (mostly organic) grains or aggregates up to 20 microns. Such large OM grains are unique among astromaterials with respect to the size. Here we report organic and isotope analyses of a large (approx.10 microns) aggregate of solid OM in the Zag clast. The X-ray micro-spectroscopic technique revealed that the OM has sp2 bonded carbon with no other functional groups nor graphitic feature (1s-sigma exciton), and thus it is distinguished from most of the OM in carbonaceous meteorites. The apparent absence of functional groups in the OM suggests that it is composed of hydrocarbon networks with less heteroatoms, and therefore the OM aggregate is similar to hydrogenated amorphous carbon (HAC). The OM aggregate has high D/H and 15N/14N ratios, suggesting that it originated in a very cold environment such as the interstellar medium or outer region of the solar nebula, while the OM is embedded in carbonate-bearing matrix resulting from aqueous activities. Thus the high D/H ratio must have survived the extensive late-stage aqueous processing. It is not in the case for OM in carbonaceous chondrites of which the D/H ratio was reduced by the alteration via the D-H exchange of water. It indicates that both the OM precursors and the water had high D/H ratios, similar to the water in Enceladus. Our results support the idea that the clast originated from Ceres, or at least, a hydrovolcanically active body similar to Ceres, and further imply that Ceres originally formed in the outer Solar System and migrated to the main belt asteroid region as suggested by the "Grand tack" scenario.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN53161
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  • 9
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    Publication Date: 2019-07-12
    Description: No abstract available
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN51668
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  • 10
    Publication Date: 2019-07-19
    Description: Astronomical measurements of S abundances in the diffuse interstellar medium (ISM) indicate ionized S is a dominant species with little (〈 5%) S residing in grains (e.g. Jenkins 2009). This is an enigmatic result, given that abundant Fe-sulfide grains are observed in dust around pre- and post-main sequence stars and are also observed as major components of primitive meteoritic and cometary samples. These disparate observations suggest that the lifetime of sulfide grains in the ISM is short because of destruction processes. Our previous work has shown that FeS and MgS retain their crystallinity and do not amorphize during radiation processing, whereas enstatite and forsterite are readily amorphized. We have extended this study to measure the relative sputtering rates of FeS and MgS compared to enstatite and forsterite. Irradiation of FeS with 4 keV He+ results in preferential sputtering of S and the formation of a thin 2-3 nm, compact Fe metal layer that armors the surface. The zone of S loss extends to a depth of ~8-10 nm below the exposed surface. Despite this S loss, the FeS retains its crystallinity and shows no sign of incipient amorphization. Irradiation of FeS with 5kV Ga+ in a focused ion beam (FIB) instrument resulted in preferential sputtering of S and the formation of a 5-8-nm thick surface layer of nanophase Fe metal. X-ray mapping shows that the zone of S sputtering extends to a depth of nearly 20 nm, but there is no evidence for FeS amorphization, consistent with our previous work. The irradiation experiments show that the relative sputtering rate of FeS and MgS are much higher than olivine or enstatite. Sputtering experiments utilizing 30 kV and 5 kV Ga ions in the FIB produced volume loss in troilite that was ~4X greater than in enstatite or forsterite. The sputter yield under these conditions is such that for every Si atom sputtered from enstatite, ~14 S atoms are sputtered from FeS. We have performed similar sputtering experiments on Fe-bearing niningerite (MgS) and co-existing enstatite from the ALH 84170 EH3 chondrite. MgS also sputters much more rapidly than enstatite with a relative Si:S sputter yield of 1:8. For MgS, sulfur is highly depleted at the surface and the S-depletion zone extends to a depth of ~15 nm (using 5 kV Ga+). There is a corresponding zone of Mg and especially Fe enrichment that extends from 5 to ~10 nm below the surface, respectively. The dominant grain destruction mechanism in the ISM is sputtering from passage of supernova-generated shock waves. This process also results in the amorphization of crystalline silicates in the ISM. Our results indicate that FeS and MgS grains produced in evolved stars and injected into the ISM will be destroyed more rapidly than crystalline silicates. This process may account for the lack of significant depletion of S from the gas phase in the ISM. However, rare nanophase FeS grains occur as inclusions in circumstellar amorphous silicate grains found in comet dust particles analyzed in the laboratory. These results show that a finite amount of S in the ISM is sequestered in solid grains.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN54311 , Cosmic Dust: Origin, Applications & Implications (CPHDUST2018); Jun 11, 2018 - Jun 15, 2018; Copenhagen; Denmark
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  • 11
    Publication Date: 2019-07-19
    Description: The Microgravity Science Glovebox (MSG) on the International Space Station (ISS) is used for fluid transfer in many types of experiments. Reagents are handled in the MSG to prevent their accidental release into the cabin. However, the MSG is currently over-subscribed, creating a backlog of users in flight. As a recourse, current experiments are underway to assess the possibility of moving certain science operations from the MSG into the open cabin of the ISS. The experiments are designed to assess the efficacy of exploiting surface tension as a control to prevent the unwanted release of liquids. Dyed water currently serves as an ersatz for potentially more hazardous liquids. Common wet-lab operations such as de/mating wetted Luer-Lok fittings, liquid-bearing container lid removal, and pipetting between well plates are performed illustrating the facility and challenges imposed by the microgravity environment. Concerning the latter, various pipette cannula sizes are deployed at various injection, withdrawal, and translations rates to map the existence, size, velocity, and trajectory of satellite droplets expected to form when breaking contact between the water surface and the pipette tip. Though such drops frequently form in terrestrial operations, they are nearly imperceptible and inconsequentialdue in part to their speed and because gravity quickly returns them to the well plate from which they came. The use of airflow to capture and collect such satellite droplets is demonstrated. The dynamic stability of the liquid-filled well plates is quantified in response to a variety of crew-imparted disturbances. From a safety perspective, the results from the STCE are of immediate practical value. If such routine low-gravity capillary fluidic operations can be established as mundane, their performance may be moved out of the MSG and into the cabin, significantly increasing the efficiency of experiments performed on ISS.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN58986 , Annual Meeting of the American Society for Gravitational and Space Research; 31 Oct. 3 Nov. 2018; Bethesda, MD; United States
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  • 12
    Publication Date: 2019-07-19
    Description: Knowing the distribution and origin of water in terrestrial planets is crucial to understand their formation, evolution and the source of their atmospheres and surface water. Mantle D/H ratios may be used to determine what type of material contributed water to the terrestrial planets [1]. However, other processes, magmatic or surface alteration processes, can also modify D/H ratios, and for Mars, we only have samples from the crust, as meteorites. The D/H ratio of igneous phases of Martian meteorites is generally explained in terms of the mixing contributions of two reservoirs: surficial with high D/H (dD 〉 700 ) related to interaction with the martian atmosphere (dD ~ 5000), and mantle-derived with lower D/H (dD 〈 500 but the exact value is still debated)[2]. However, our present study evidences that H loss in clinopyroxene during degassing can significantly fractionate H isotopes and increase their D/H ratios. In situ analyses of H isotopes, and of water, major and trace element contents were performed on the pyroxenes of 5 nakhlites. Nakhlites are clinopyroxenites that likely originated from the same lava flow or shallow magma chamber. Water contents decrease (380 to 〈5 ppm H2O) with increasing dD (-268 to 4860 ). Significant influence from spallation, exchange with the martian atmosphere, shock, surface alteration, and hydrothermal processes is ruled out. Together with the evidence of less water at the edge of individual pyroxene grains compared to their interior, we interpret this correlation as the result of preferential diffusive loss of H relative to D from the already crystallized pyroxenes during ascent of the partially-crystallized magma. Similar H isotope fractionations have been observed in another nominally anhydrous mineral, garnet, during experimental dehydration [3]. These results emphasize that caution is warranted when interpreting H isotope analyses of igneous, nominally anhydrous minerals in terms of planetary processes.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN61638 , 2018 AGU Fall Meeting; Dec 10, 2018 - Dec 14, 2018; Washington, DC; United States
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  • 13
    Publication Date: 2019-07-19
    Description: Meteoroid environment models must describe the mass, directionality, velocity, and density distributions of meteoroids in order to correctly predict the rate at which meteoroids impact spacecraft. We present an updated version of NASA's Meteoroid Engineering Model (MEM) that better captures the correlation between directionality and velocity and incorporates a bulk density distribution. We compare the resulting model with the rate of large particle impacts seen on the Long Duration Exposure Facility (LDEF) and the Pegasus I and II satellites. The updated model shows closer agreement with these in situ data than previous versions of MEM.
    Keywords: Space Sciences (General)
    Type: M18-6855 , Division for Planetary Sciences; Oct 21, 2018 - Oct 26, 2018; Knoxville, TN; United States
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  • 14
    Publication Date: 2019-07-19
    Description: Impact structures are prone to erosion, burial and tectonic deformation. The Santa Fe impact structure in New Mexico contains shatter cones and shocked quartz, but is highly tectonized and eroded; estimates of the impact age (1200-300 Ma) and size (6-13 km) are poorly constrained. Here we report the first occurrence of shock-twinned zircon identified both in modern sediments and bedrock at the Santa Fe impact structure. Zircon {112} twin lamellae are considered diagnostic evidence of shock deformation and have been identified at several impact structures including Vredefort, Sudbury, Ries, Rock Elm, and in lunar impact breccia. A total of 6619 grains from fifteen sediment samples and two rock samples were surveyed; seven shocked grains were identified (7/6619 = 0.1%). One shocked zircon was identified in a biotite schist shatter cone. Five of seven shocked zircon grains were EBSD mapped; three were analyzed with multiple SIMS spots. EBSD mapping revealed {112} deformation twin lamellae in each of the five zircon grains. U-Pb geochronology for three of the shocked zircon grains yield crystallization ages from 1715+/-22 to 1472+/-35 Ma. LA-ICPMS U-Th-Pb analysis of detrital zircon grains from five samples yielded Paleoproterozoic (1800-1600 Ma) and Mesoproterozoic (1500-1300 Ma) ages. We reveal the first confirmed shocked zircon at the Santa Fe structure. Zircon is the third shocked mineral identified at this site, in addition to xenotime and quartz]; the {112} twin lamellae indicate that exposed bedrock may have experienced shock pressures up to ~20 GPa. The 1472+/-35 Ma age determined from a shock-twinned zircon is the first reliable maximum impact age constraint based on analysis of shocked material and extends the window for the Santa Fe impact event into the Mesoproterozoic.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN61019 , Annual Meeting Geological Society of America; Nov 04, 2018 - Nov 07, 2018; Indianapolis, IN; United States
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  • 15
    Publication Date: 2019-07-20
    Description: For the Orion Multi-Purpose Crew Vehicle (MPCV) project, NASA is minimizing the use of onboard diagnostics, especially external sensors that penetrate the structure. Nonetheless, there is a desire to measure the Thermal Protection System (TPS) recession during reentry. One noninvasive technique currently under investigation is the insertion of indicator metals into the heatshield at varied depths and spatial locations. A remote (airborne) spectrometer detects the emissions from the ionized metal to reveal the time (thus depth) of the metal release. Innovative processing enables the emission features from trace amounts of the selected metals to be reliably detected against the complex and structured spectral background of the shock layer and ablated TPS material. The con-cept has been proven viable through ground testing at NASA HyMETS and AHF arc jet facilities using the Orion TPS material (Avcoat). This presentation highlights the parametric testing that was conducted to select the optimal indicator metals and to assess the accuracy of remote recession measurements using this technique. The CONOPS for integrating the technique into the Orion flight tests is also presented. This includes the onboard indicator metal "seeded plugs" and the offboard airborne sensor platform that would be deployed.
    Keywords: Space Sciences (General)
    Type: ARC-E-DAA-TN57510 , National Space & Missile Materials Symposium (NSMMS); Jun 25, 2018 - Jun 28, 2018; Madison, WI; United States
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  • 16
    Publication Date: 2019-07-20
    Description: Accessory mineral geochronometers such as zircon, monazite, baddeleyite, and xenotime are increasingly being recognized for their ability to preserve diagnostic microstructural evidence of hypervelocity processes. However, little is known about the response of titanite to shock metamorphism, even though it is a widespread accessory phase and U-Pb geochronometer. Here we report two new mechanical twin modes in titanite within shocked granitoids from the Chicxulub impact structure, Mexico. Titanite grains in the newly acquired International Ocean Discovery Program Site expedition 364 M0077A core preserve multiple sets of polysynthetic twins, most commonly with composition planes (K1), = ~{111}, and shear direction (1) = 〈110〉, and less commonly with the mode K1 = {130}, 1 = ~〈522〉. In some grains, {130} deformation bands have formed concurrently with shock twins, indicating dislocation glide with Burgers vector b = [341] can be active at shock conditions. Twinning of titanite in these modes, the presence of planar deformation features in shocked quartz, and lack of diagnostic shock microstructures in zircon in the same samples highlights the utility of titanite as a shock indicator for a shock pressure range between ~12 and ~17 GPa. Given the challenges of identifying ancient impact evidence on Earth and other bodies, microstructural analysis of titanite is here demonstrated to be a new avenue for recognizing impact deformation in materials where other impact evidence may be erased, altered, or did not manifest due to low shock pressure.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN64247 , SSERVI Australia Workshop; Nov 28, 2018; Perth, Western Australia; Australia
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  • 17
    Publication Date: 2019-07-19
    Description: The 23 km-diameter, ca. 24 Ma Haughton Dome impact structure in the Canadian Arctic on Devon Island, Nunavut (89deg41W, 75deg22N) occurred within a two layered target composed of a shallowly-dipping ~1700 m thick succession of Paleozoic limestones and evaporates overlying ca.1.9 Ga high grade gneisses [1, 2]. Within the structure a well preserved impact melt bearing breccia unit contains a variety of shocked clasts from the pre-impact sediments and basement gneisses [3]. Due to their high level of preservation a variety of studies have been undertaken on the clast population of the melt bearing breccia, including characterization of shock within the accessory minerals of the basement lithologies [4, 5]. This study presents high resolution electron backscatter diffraction (EBSD) microstructural data for zircon and monazite from historic samples of the basement gneiss, in which bulk shock pressures have been previously constrained based on major phases [4, 6]. Shocked zircon and monazite grains have been investigated from shock stage 1b (sample 72110), 2 (7273) and 3 (7192, Dig-9) [4, 6]. At lower shock levels zircon displays planar microstructures consistent with mechanical shock {112} twin formation [7] and deviatoric transformation to the high pressure polymorph reidite [8]. Zircon grains from shock stage three show a more chaotic microstructure with multiple orientations of tightly spaced sets of reidite that are variably recrystallized to zircon neoblasts. Monazite from lower shock stages contains a number of mechanical twin orientations that are indicative of shock deformation [9]. At higher shock pressures a lath like structure of interlocking twin orientations has been identified. This microstructure is suggestive of a reversion transformation from a high pressure polymorph [10] and is the first evidence for the transformation of monazite during shock.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN60816 , Annual Meeting Geological Society of America; Nov 04, 2018 - Nov 07, 2018; Indianapolis, IN; United States
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  • 18
    Publication Date: 2019-07-19
    Description: For over five decades of manned spaceflight missions, NASA astronauts have taken extraordinary photographs of Earth's surface and dynamic processes. Humans on board the International Space Station (ISS) have a unique platform to perform Earth observations at various viewing angles, seasons, and times of day. Astronaut photos taken from the ISS comprise a truecolor (RGB) dataset taken with multiple handheld digital cameras and lens types (prior to 2004, film cameras were in use). Earth observations through astronaut photography are an important and unique remote sensing method when monitoring natural disasters, urban growth, and environmental changes. While astronaut imagery can be used for earth science research, there is also an artistic aspect to the photography that fascinates a wide global population. A broader public audience can be introduced to earth science through high resolution, Earth art photos taken from the perspective of an astronaut. The Crew Earth Observations (CEO) Facility within the Earth Science and Remote Sensing Unit at NASA's Johnson Space Center supports the acquisition, analysis, and curation of astronaut photography of Earth's surface and atmosphere. CEO's website, the Gateway to Astronaut Photography of Earth (eol.jsc.nasa.gov), provides free public access to view, search, and download over three million images taken by astronauts throughout all of NASA's crewed spaceflight history, with an emphasis on current ISS imagery. The CEO Facility actively curates a digital collection of exceptional Earth art astronaut photos used for public engagement. Our new Downloadable Earth Art page focuses on broad earth science topics including: mountains, water, clouds, agriculture, as well as an "abstract" category. This continuouslyupdated collection is comprised of freely accessible and highquality downloadable materials, such as single and dualscreen digital wallpapers. All Earth Art materials are presented with sciencebased information that complements the artistic qualities of the imagery, and facilitate connections between general audiences and earth science from the International Space Station.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN60439 , Annual Meeting Geological Society of America; Nov 04, 2018 - Nov 07, 2018; Indianapolis, IN; United States
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  • 19
    Publication Date: 2019-07-19
    Description: Throughout the lifetime of the solar system, collisions between small bodies and impacts on the surfaces of small bodies in the Kuiper Belt have occured at speeds of 1.5 - 3 km s-1 (Stern, Astron J 124, 2002), typically at 1-10 km s-1 between Trojan asteroids (Marzari et al. Icarus 119, 1996), and at ~4-8 km s-1 in the asteroid belt (Farinella and Davis, Icarus 97, 1992). Shock effects recorded by minerals composing these bodies are one observable legacy of this evolutionary process, whether they were generated through large collisions, micrometeoroid impacts, or processing during the formation of the solar system. Shock metamorphism has been observed in cometary samples such as those from Comet Wild 2 (Keller et al. Geochim. Cosmochim. Acta 72, 2008; Tomeoka et al. MAPS 43, 2008; Jacobs et al. MAPS 44, 2009) as well as in forsterites and enstatites found in meteorites (McCausland et al. AGU, 2010). To investigate the observable signatures of these processes, we have conducted a suite of impact experiments at NASA Johnson Space Center's Experimental Impact Laboratory (EIL). Target materials included Mg-rich forsterite (olivine), Mg-rich enstatite (orthopyroxene), and antigorite and lizardite (both in the serpentine group of phyllosilicates). Alumina-ceramic spheres were launched at speeds ranging from ~2.0 - 2.6 km s-1 into targets at temperatures from 25degC to -100degC. Recent advancements have been made in cooling targets in the EIL's vertical gun. Liquid nitrogen (LN2) is fed through a unique jacket surrounding the metallic sample container to chill the samples. Real-time values from temperature sensors attached to the sample holder are converted to target temperature through predetermined regression relationships, providing the target temperature at the time of impact with sub-degree accuracy. Fourier Transform Infrared Spectrometer (FTIR) data in the near to mid-IR will be presented, along with trends relating temperature and velocity with impact speeds, and thereby peak shock stresses experienced by the impacted minerals.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN60814 , Division for Planetary Sciences Meeting; Oct 21, 2018 - Oct 26, 2018; Knoxville, TN; United States
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  • 20
    Publication Date: 2019-07-20
    Description: Shock deformed monazite, mono-clinic rare earth element (REE) phosphate, from the Haughton Dome impact structure, Nunavut, Canada, contain lath-structured lamellae. Microstructural phase heritage indicate the former presence of a previously unreported, shock-produced, tetragonal-structured, high pressure polymorph of REEPO4. This study presents an electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) study of shock deformed monazite from the historic sample DIG-9, a shock stage III, biotite sillimanite gneiss sample from near the central uplift of the Haughton Dome (7522'20"N, 8940'50"W), in which shock features in monazite were first described.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN64828 , Lunar and Planetary Science Conference (LPSC 2019); 18ý22 Mar. 2019; The Woodlands, TX; United States
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  • 21
    Publication Date: 2019-07-20
    Description: The Nadir and Occultation for MArs Discovery instrument (NOMAD), onboard the ExoMars Trace Gas Orbiter (TGO) spacecraft was conceived to observe Mars in solar occultation, nadir, and limb geometries, and will be able to produce an outstanding amount of diverse data, mostly focused on properties of the atmosphere. The infrared channels of the instrument operate by combining an echelle grating spectrometer with an Acousto- Optical Tunable Filter (AOTF). Using in-flight data, we characterized the instrument performance and parameterized its calibration. In particular: an accurate frequency calibration was achieved, together with its variability due to thermal effects on the grating. The AOTF properties and transfer function were also quantified, and we developed and tested a realistic method to compute the spectral continuum transmitted through the coupled grating and AOTF system. The calibration results enabled unprecedented insights into the important problem of the sensitivity of NOMAD to methane abundances in the atmosphere. We also deeply characterized its performance under realistic conditions of varying aerosol abundances, diverse albedos and changing illumination conditions as foreseen over the nominal mission. The results show that, in low aerosol conditions, NOMAD single spectrum, 1 sensitivity to CH4 is around 0.33 ppbv at 20 km of altitude when performing solar occultation's, and better than 1 ppbv below 30 km. In dusty conditions, we show that the sensitivity drops to 0 below 10 km. In Nadir geometry, results demonstrate that NOMAD will be able to produce seasonal maps of CH4 with a sensitivity around 5 ppbv over most of planet's surface with spatial integration over 55 bins. Results show also that such numbers can be improved by a factor of ~10 to ~30 by data binning. Overall, our results quantify NOMAD's capability to address the variable aspects of Martian climate.
    Keywords: Space Sciences (General)
    Type: GSFC-E-DAA-TN63154 , Icarus; 321; 671-690
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  • 22
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-07-20
    Description: Please see attachment.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN66654 , The Next Generation of Thermal-IR Astronomy: How can we Reach the Photon Noise Limit?; Nov 12, 2018 - Nov 16, 2018; Leiden; Netherlands
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  • 23
    Publication Date: 2019-07-20
    Description: The monolithic steel plate traditionally used to intercept sabot pieces during light-gas gun operations was replaced by low density material. The idea was to decrease the shock stress in these plastic sabot pieces to values below the vaporization threshold, thereby reducing the prominent soot-deposits that characterize typical target surfaces. The project was a collaboration between Orbital Debris and Planetary Science interests at JSC/ARES.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN61951 , Technology Showcase at JSC; Oct 22, 2018; Houston, TX; United States
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  • 24
    Publication Date: 2019-07-20
    Description: No abstract available
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN62122
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  • 25
    Publication Date: 2019-07-20
    Description: Purpose: (1) Provide data to develop, update, and/or verify ballistic limit equations used in the MMOD risk assessment. (2) Provide data used to compare two or more shielding options to reduce MMOD risk. (3) Determine failure modes and failure criteria for hardware: (a) Failure modes: how hardware fails (pressure vessels, pressurized lines, electronic hardware, power cables). (b) Failure criteria: quantify damage level that results in hardware failure (for example: depth of penetration into pressure vessel that results in leak or burst).
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN62120
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  • 26
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Space Sciences (General)
    Type: MSFC-E-DAA-TN63767 , 2018 AGU Fall Meeting; Dec 10, 2018 - Dec 14, 2018; Washington, DC; United States
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  • 27
    Publication Date: 2019-07-13
    Description: Unsteady processes in the solar wind magnetosphere interaction, such as vortices developed at the magnetopause boundary by the KelvinHelmholtz instability, may contribute to the process of mass, momentum and energy transfer into the Earths magnetosphere. The research described in this paper validates an algorithm to automatically detect and characterize vortices based on velocity data from simulations. The vortex identification algorithm (VIA) systematically searches the 3-D velocity fields to identify critical points where the magnitude of the velocity vector vanishes. The velocity gradient tensor is computed and its invariants are used to assess vortex structure in the flow field. We use the Community Coordinated Modeling Center (CCMC) Runs on Request capability to create a series of model runs initialized from the conditions observed by the Cluster mission in the Hwang et al. (2011) analysis of KelvinHelmholtz vortices observed during southward interplanetary magnetic field (IMF) conditions. We analyze further the properties of the vortices found in the runs, including the velocity changes within their motion across the magnetosheath. We also demonstrate the potential of our tool to identify and characterize other transient features (e.g., flux transfer events, FTEs) with vortical internal structures. We find that the vortices are associated with flows on the magnetosheath side of the magnetopause that reach speeds greater than the solar wind speed at the bow shock.
    Keywords: Space Sciences (General)
    Type: GSFC-E-DAA-TN65927 , Annales Geophysicae (ISSN 0992-7689) (e-ISSN 1432-0576); 36; 4; 1117-1129
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  • 28
    Publication Date: 2019-07-13
    Description: Of the C3Hx hydrocarbons, propane (C3H8) and propyne (methylacetylene, CH3C2H) were first detected in Titans atmosphere during the Voyager 1 flyby in 1980. Propene (propylene, C3H6) was first detected in 2013 with data from the Composite InfraRed Spectrometer (CIRS) instrument on Cassini. We present the first measured abundance profiles of propene on Titan from radiative transfer modeling, and compare our measurements to predictions derived from several photochemical models. Near the equator, propene is observed to have a peak abundance of 10 ppbv at a pressure of 0.2 mbar. Several photochemical models predict the amount at this pressure to be in the range 0.31 ppbv and also show a local minimum near 0.2 mbar which we do not see in our measurements. We also see that propene follows a different latitudinal trend than the other C3 molecules. While propane and propyne concentrate near the winter pole, transported via a global convective cell, propene is most abundant above the equator. We retrieve vertical abundances profiles between 125 km and 375 km for these gases for latitude averages between 60S20S, 20S20N, and 20N60N over two time periods, 2004 through 2009 representing Titans atmosphere before the 2009 equinox, and 2012 through 2015 representing time after the equinox. Additionally, using newly corrected line data, we determined an updated upper limit for allene (propadiene, CH2CCH2, the isomer of propyne). We claim a 3- upper limit mixing ratio of 2.5 10(exp 9) within 30 of the equator. The measurements we present will further constrain photochemical models by refining reaction rates and the transport of these gases throughout Titans atmosphere.
    Keywords: Space Sciences (General)
    Type: GSFC-E-DAA-TN65922 , Icarus (ISSN 0019-1035); 317; 454-469
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  • 29
    Publication Date: 2019-07-13
    Description: We report MMS observations of the ion-scale flux transfer events (FTEs) that may involve two main X lines and tearing instability between the two X lines. The four spacecraft detected multiple isolated regions with enhanced magnetic field strength and bipolar B(sub )n signatures normal to the nominal magnetopause, indicating FTEs. The currents within the FTEs flow mostly parallel to B, and the magnetic tension force is balanced by the total pressure gradient force. During these events, the plasma bulk flow velocity was directed southward. Detailed analysis of the magnetic and electric field and plasma moments variations suggests that the FTEs were initially embedded within the exhaust region north of an X line but were later located southward/downstream of a subsequent X line. The cross sections of the individual FTEs are in the range of ~2.5-6.8 ion inertial lengths. The observations suggest the formation of multiple secondary FTEs. The presence of an X line in the exhaust region southward of a second X line results from the southward drift of an old X line and the reformation of a new X line. The current layer between the two X lines is unstable to the tearing instability, generating multiple ion-scale flux-rope-type secondary islands.
    Keywords: Space Sciences (General)
    Type: GSFC-E-DAA-TN65910 , Journal of Geophysical Research: Space Physics (ISSN 2169-9402) (e-ISSN 2169-9380); 123; 10; 8473-8488
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  • 30
    Publication Date: 2019-07-13
    Description: While the earliest history of many planetary bodies within the inner Solar System is dominated by intense bombardment, this record is missing from Earth due to active tectonics and erosion. Where-as rocks from the earliest history of Earth are absent, mineral relics, such as ancient detrital zircon concentrated in sediments within the Jack Hills, Narryer, Illara and Maynard Hills greenstone belts of the Yilgarn Craton in Western Australia preserve a record of this time.Shock in zircon: During shock deformation, resulting from hyper-velocity impact, zircon can be modified in crystallographically-controlled ways. This includes the development of planar and subplanar low-angle grain boundaries, the formation of mechanical twins, transformation to the high pressure polymorph reidite, development of polycrystalline microtexture, and dissociation to its dioxide constituents SiO2 and ZrO2.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN60129 , The First Billion Years: Bombardment Conference; Sep 30, 2018 - Oct 02, 2018; Flagstaff, AZ; United States
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  • 31
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Space Sciences (General)
    Type: MSFC-E-DAA-TN60736 , Towards a Network of GRB Detecting Nansato; Sep 14, 2018; Budapest; Hungary
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  • 32
    Publication Date: 2019-07-13
    Description: Clean room standards like ISO 14644 used for facilities that construct spacecraft and store returned samples do not explicitly account for microbial contamination. While there are associated ISO standards for monitoring and controlling bio-contamination in clean rooms it is not always standard practice to do so. The NASA Astromaterials Acquisition and Curation Office maintains seven separate clean labs for storing extraterrestrial samples from the Moon, meteorites, cosmic dust, asteroids, comets, solar wind particles, and microparticle impact samples. These labs are routinely monitored for particulate and trace metal contamination. However, the sample collections are either non-sterile at the time of collection (e.g., meteorites) or are no longer being used to address scientific questions that could be affected by non-sterile conditions (e.g., Lunar samples). Outside of isolated studies there has not been a systematic, longitudinal characterization of the microbial ecology of NASA curation clean rooms. In accordance with the advanced curation initiative, and to prepare for future sample return missions, we have initiated a routine microbiological monitoring program in the Antarctic Meteorite Lab. This monitoring program will be used to determine what microbes are capable of surviving in these oligotrophic environments and whether or not they are capable of altering the sample collections in any significant manner. Repeat sampling will allow us to understand how routine use of these labs affects the microbial ecology over time.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN52831 , COSPAR Scientific Assembly; Jul 14, 2018 - Jul 22, 2018; Pasadena, CA; United States
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  • 33
    Publication Date: 2019-07-13
    Description: "Chromospheric LAyer Spectro-Polarimeter (CLASP2)" is the next sounding rocket experiment of the "Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP)" that succeeded in observing for the first time the linear polarization spectra in the hydrogen Lyman- line (121.6 nm) and is scheduled to be launched in 2019. In CLASP2, we will carry out full Stokes-vector spectropolarimetric observations in the Mg II h & k lines near 280 nm with the spectro-polarimeter (SP), while imaging observations in the Lyman- line will be conducted with the slitjaw optics (SJ). For the wavelength selection of CLASP2, the primary mirror of the telescope uses a new dual-band pass cold mirror coating targeting both at 121.6 nm and 280 nm. Therefore, we have to perform again the alignment of the telescope after the installation of the recoated primary mirror. Before unmounting the primary mirror from the telescope structure, we measured the wave-front error (WFE) of the telescope. The measured WFE map was consistent with what we had before the CLASP flight, clearly indicating that the telescope alignment has been maintained even after the flight. After the re-coated primary mirror was installed the WFE was measured, and coma aberration was found to be larger. Finally, the secondary mirror shim adjustments were carried out based on the WFE measurements. In CLASP2 telescope, we improved a fitting method of WFE map (applying 8th terms circular Zernike polynomial tting instead of 37th terms circular Zernike fitting) and the improved method enables to achieve better performance than CLASP telescope. Indeed, WFE map obtained after the final shim adjustment indicated that the required specification (〈 5:5 m RMS spot radius) that is more stringent than CLASP telescope was met.
    Keywords: Space Sciences (General)
    Type: MSFC-E-DAA-TN58632 , SPIE Astronomical Telescopes & Instrumentation; Jun 10, 2018 - Jun 15, 2018; Austin, TX; United States
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  • 34
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Space Sciences (General)
    Type: ARC-E-DAA-TN57049 , International Planetary Probe Workshop; Jun 11, 2018 - Jun 15, 2018; Bouder, CO; United States
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  • 35
    Publication Date: 2019-07-13
    Description: We use a global magnetohydrodynamics simulation to analyze transient magnetic reconnection processes at the magnetopause. The solar wind conditions have been kept constant, and an interplanetary magnetic field with large duskward BY and southward BZ components has been imposed. Five flux transfer events (FTEs) with clear bipolar magnetic field signatures have been observed. We observed a peculiar structure defined as interlinked flux tubes (IFTs) in the first and fourth FTE, which had very different generation mechanisms. The first FTE originates as an IFTs and remains with this configuration until its final moment. However, the fourth FTE develops as a classical flux rope but changes its 3-D magnetic configuration to that of IFTs. This work studies the mechanism for generating IFTs. The growth of the resistive tearing instability has been identified as the cause for the first IFTs formation. We believe that the instability has been triggered by the accumulation of interplanetary magnetic field at the subsolar point where the grid resolution is very high. The evidence shows that two new reconnection lines form northward and southward of the subsolar region. The IFTs have been generated with all the classical signatures of a single flux rope. The other IFTs detected in the fourth FTE developed as a result of magnetic reconnection inside its complex and twisted magnetic fields, which leads to a change in the magnetic configuration from a flux rope of twisted magnetic field lines to IFTs.
    Keywords: Space Sciences (General)
    Type: GSFC-E-DAA-TN58278 , Journal of Geophysical Research: Space Physics (ISSN 2169-9380) (e-ISSN 2169-9402); 123; 2; 1337-1355
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  • 36
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Space Sciences (General)
    Type: MSFC-E-DAA-TN61234 , Magnetotail Reconnection Onset and Dipolarization Fronts; Sep 18, 2018 - Sep 20, 2018; Laurel, MD; United States
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  • 37
    Publication Date: 2019-07-13
    Description: The Habitable Exoplanet Observatory (HabEx) mission has unique optical performance requirements which drive the mirror design process beyond the traditional criteria. While mass and stiffness are still important, the response to inertia loading (expressed in terms of Zernike coefficients) to omni-directional excitation dominates the effort. While a Zerodur mirror is the current baseline, as mass budgets change, a ULE design is being studied as a potential alternative. This trade study looked at over 264 design variations using the Arnold Mirror Modeler and ANSYS(c) to investigate the influence of various design elements, including: substrate thickness, core cell size, hexapod geometry and local reinforcement. Design 'goodness' was evaluated based on the mirror's inertial deformation response to omni-directional input. This response was calculated via RSSing Zernike polynomial responses to (XYZ) accelerations.
    Keywords: Space Sciences (General)
    Type: MSFC-E-DAA-TN61193 , Optics and Photonics Conference Proceedings; Aug 19, 2018 - Aug 23, 2018; San Diego, CA; United States
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  • 38
    Publication Date: 2019-07-13
    Description: Selected original analog telemetry tapes from three of the topside-sounder satellites of the International Satellites for Ionospheric Studies (ISIS) program, namely Alouette 2, ISIS I, and ISIS II, were used in an earlier project to produce more than million digital topside ionograms; the resulting digital topside ionograms from ISIS II were used to produce morethan 86,000 globally-distributed vertical topside ionospheric electron density profiles Ne(h)that cover a time span of more than a solar cycle. These Ne(h) were produced using the TOPIST auto-scaling software. Before attempting to automatically process Alouette-2 orISIS-I ionograms a data-enhancement project was initiated so as to increase the auto processing success rate. These enhancements were mainly to correct problems that often occurred during the analog-to-digital conversion of the original telemetry tapes. Here we present the status of, and results from, this ongoing enhancement effort.
    Keywords: Space Sciences (General)
    Type: GSFC-E-DAA-TN44000 , Conference Proceedings; Jun 21, 2018; Greenbelt, MD; United States
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  • 39
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Space Sciences (General)
    Type: MSFC-E-DAA-TN57607 , SPIE Astronomical Telescopes & Instrumentation; Jun 10, 2018 - Jun 15, 2018; Austin, TX; United States
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  • 40
    Publication Date: 2019-07-13
    Description: Next Generation X-Ray Optics (NGXO) team at the Goddard Space Flight Center (GSFC) has been developing a new silicon-based grazing incidence mirror technology for future high resolution x-ray astronomical missions. Recently, the GSFC team completed the construction of first few mirror modules that contain one pair of mirrors. One of the mirror pairs was tested in GSFC 600-m long beamline facility and Panter (Neuried, Germay) 120-m long x-ray beamline facility. Both full aperture x-ray tests, Hartmann tests, and focal plane sweeps were completed. In this paper we present the data analysis process and compare the results from our models to measured x-ray centroid data, x-ray performance data, and out of focus images of the mirror pair.
    Keywords: Space Sciences (General)
    Type: GSFC-E-DAA-TN56866 , SPIE Astronomical Telescopes + Instrumentation; Jun 10, 2018 - Jun 15, 2018; Austin, TX; United States
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  • 41
    Publication Date: 2019-07-13
    Description: The Astromaterials Acquisition and Curation Office at NASA Johnson Space Center (JSC) is re-sponsible for curating all of NASA's extraterrestrial samples. The NASA Curation Office plans for the requirements of future collections in an ''Advanced Curation'' program. Advanced Curation is tasked with developing procedures, technology, and data sets necessary for curating new types of collections as envisioned by NASA exploration goals. Here we review the science value of some potential targets for sample return missions from the inner solar system over the next 43 years.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN53712 , Technologies and Infrastructures Workshop for Planetary Exploration, Horizon 2061; Apr 23, 2018 - Apr 25, 2018; Lusanne; Switzerland
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  • 42
    Publication Date: 2019-07-13
    Description: Based on meteoritic evidence, Mars accreted as early as 2 Ma after the formation of the first solids in the solar system from material with an O-Ti-Cr-Ni isotopic provenance distinct from the Earth- Moon system. It likely formed a magma ocean within approx. 100 Ma after solar system formation, from which the martian core last equilibrated with its mantle at pressures of approx. 14 GPa. The formation of most of the mass of the Martian crust is constrained to have occurred by 4.35 Ga. Remanent magnetization in martian meteorite ALH 84001 demonstrates a dynamo had initiated on Mars at or before 4.1 Ga. Sample return is necessary because meteorites lack geologic context and their orientation with respect to the paleomagnetic field is not known.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN52601 , International Mars Sample Return Conference; Apr 25, 2018 - Apr 27, 2018; Berlin; Germany
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  • 43
    Publication Date: 2019-07-13
    Description: Volatiles have clearly played a key role in the evolution of Mars' atmosphere, hydrosphere and geosphere, with effects ranging from the geomorphological evidence for outflow channels and valley networks early in Mars' history to formation of alteration products in rocks to the current seasonal changes in the polar caps. It is clear that the absolute and relative abundances of various volatiles have changed through time via volcanic degassing, atmospheric loss, and interactions with the crust.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN52624 , International Mars Sample Return Conference; Apr 25, 2018 - Apr 27, 2018; Berlin; Germany
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  • 44
    Publication Date: 2019-07-13
    Description: The formal life-related objective of the M-2020 sample-collecting rover is to seek the signs of ancient life. The rover will not enter ''special regions'' on Mars where Earth life may replicate or extant Martian life forms are likely to exist. Therefore, returned samples will not specifically be chosen for the purpose of discovering extant life unless something unexpected is encountered in the field. Regardless, the astrobiological community is highly interested investigating whether or not there is extant life in/on these samples.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN52628 , International Mars Sample Return Conference; Apr 25, 2018 - Apr 27, 2018; Berlin; Germany
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  • 45
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-07-13
    Description: Evidence of habitability and habitation of Mars may be forthcoming by returning samples to Earth. Clear objectives and associated choices of samples is essential to maximize the opportunities presented by returned samples. In the context of the solar system, the relative similarity of Earth and Mars generates an expectation of biochemical harmony for Earth and Mars. We can confidently predict that any biochemical scaffolding on Mars would be based on carbon and any biochemical solvent would be based on water. To expect otherwise would require planetary conditions and chemistries that differ dramatically from those of either Earth or Mars. Reduced carbon is therefore a beacon for the potential discovery of evidence of life in a sample. Any reduced carbon detected in samples from Mars should also have features that provide the ability to discriminate between non-life and life sources and, preferably, between an origin on Earth and Mars. For detecting life, the usefulness of organic carbon to biochemistry is in its ability to form complex and specific organic structures.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN52623 , International Mars Sample Return Conference; Apr 25, 2018 - Apr 27, 2018; Berlin; Germany
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  • 46
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Space Sciences (General)
    Type: ARC-E-DAA-TN51783 , Mini-Workshop to Apply Recent Models for Asteroid Airbursts to the Tunguska Event; Jan 16, 2018; Moffett Field, CA; United States
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  • 47
    Publication Date: 2019-07-13
    Description: Metallic cores contain light alloying elements that can be a combination of S, C, Si, and O, all of which have important chemical and physical influences. For Earth, Si may be the most abundant light element in the core. Si dissolved into Fe liquids can have a large effect on the magnitude of the activity coefficient of siderophile elements (SE), and thus the partitioning behavior of those elements between core and mantle. The effect of Si on the highly siderophile elements is only beginning to be studied and the effects on Au, Pd and Pt are significant. Here we report new experiments designed to quantify the effect of Si on the partitioning of Re between metal and silicate melt. A solid understanding of Re partitioning is required for a complete understanding of the Re-Os isotopic systems. The results will be applied to understanding the HSEs and Os isotopic data for planetary mantles, and especially Earth.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN52042 , Lunar and Planetary Science Conference; Mar 19, 2018 - Mar 23, 2018; Woodlands, TX; United States
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  • 48
    Publication Date: 2019-07-13
    Description: In previous work we proposed a hypothesis wherein debris moving along cometary orbits interacting with Mars (e.g. meteor showers) may be responsible for transient local increases of methane observed in the martian atmosphere (henceforth 'the hypothesis' ). An examination of the literature of methane detections dating back to 1997 showed that each detection was made, at most, 16 days after an interaction between Mars and one of seven small bodies (six comets and the unusual object 5335 Damocles)[ibid]. Two observations of high-altitude, transient visible plumes on Mars also correlate with cometary interactions, one occurring on the same day as the plume observation and the second observation occurring three days afterwards, and with two of the same seven small bodies. The proposed mechanism for methane production is dissemination of carbon-rich cometary material on infall into Mars' atmosphere followed by methane production via UV photolysis, a process that has been observed in laboratory experiments. Given this set of observations it is necessary and indeed conducive to the scientific process to explore and robustly test the hypothesis.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN52121 , Lunar and Planetary Science Conference; Mar 19, 2018 - Mar 23, 2018; Woodlands, TX; United States
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  • 49
    Publication Date: 2019-07-13
    Description: Space Missions in 2017 Earth Satellite Population Collision Avoidance Maneuvers Post mission Disposal of U.S.A. Spacecraft Space Situational Awareness (SSA) and the Space Debris Sensor (SDS) A total of 86 space launches placed more than 400 spacecraft into Earth orbits during 2017, following the trend of increase over the past decade NASA has established conjunction assessment processes for its human spaceflight and uncrewed spacecraft to avoid accidental collisions with objects tracked by the U.S. Space Surveillance Network - NASA also assists other U.S. government spacecraft owners with conjunction assessments and subsequent maneuvers The ISS has conducted 25 debris collision avoidance maneuvers since 1999 - None in 2016-2017, but an ISS visiting vehicle had one collision avoidance maneuver in 2017 During 2017 NASA executed or assisted in the execution of 21 collision avoidance maneuvers by uncrewed spacecraft - Four maneuvers were conducted to avoid debris from Fengyun-1C - Two maneuvers were conducted to avoid debris from the collision of Cosmos 2251 and Iridium 33 - One maneuver was conducted to avoid the ISS NASA has established conjunction assessment processes for its human spaceflight and uncrewed spacecraft to avoid accidental collisions with objects tracked by the U.S. Space Surveillance Network - NASA also assists other U.S. government spacecraft owners with conjunction assessments and subsequent maneuvers The ISS has conducted 25 debris collision avoidance maneuvers since 1999 - None in 2016-2017, but an ISS visiting vehicle had one collision avoidance maneuver in 2017 During 2017 NASA executed or assisted in the execution of 21 collision avoidance maneuvers by uncrewed spacecraft - Four maneuvers were conducted to avoid debris from Fengyun-1C - Two maneuvers were conducted to avoid debris from the collision of Cosmos 2251 and Iridium 33 The 2014-15 NASA Engineering and Safety Center (NESC) study on the micrometeoroid and orbital debris (MMOD) assessment for the Joint Polar Satellite System (JPSS) provided the following findings - Millimeter-sized orbital debris pose the highest penetration risk to most operational spacecraft in LEO - The most effective means to collect direct measurement data on millimetersized debris above 600 km altitude is to conduct in situ measurements - There is currently no in situ data on such small debris above 600 km altitude Since the orbital debris population follows a power-law size distribution, there are many more millimeter-sized debris than the large tracked objects - Current conjunction assessments and collision avoidance maneuvers against the tracked objects (which are typically 10 cm and larger) only address a small fraction (〈1%) of the mission-ending risk from orbital debris To address the millimeter-sized debris data gap above 600 km, NASA has recently developed an innovative in situ measurement instrument - the Space Debris Sensor (SDS) - One maneuver was conducted to avoid the ISS
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN51994 , Scientific and Technical Subcommittee (STSC) Meeting; Jan 29, 2018 - Feb 09, 2018; Vienna; Austria
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  • 50
    Publication Date: 2019-07-13
    Description: Vulnerability of man-made infrastructure to Earth-directed space weather events is a serious concern for today's technology-dependent society. Space weather-driven geomagnetically induced currents (GICs) can disrupt operation of extended electrically conducting technological systems. The threat of adverse impacts on critical technological infrastructure, like power grids, oil and gas pipelines, and communication networks, has sparked renewed interest in extreme space weather. Because extreme space weather events have low occurrence rate but potentially high impact, this presents a major challenge for our understanding of extreme GIC activity. In this chapter, we discuss some of the key science challenges pertaining to our understanding of extreme events. In addition, we present an overview of GICs including highlights of severe impacts over the last 80 years and recent U.S. Federal actions relevant to this community.
    Keywords: Space Sciences (General)
    Type: GSFC-E-DAA-TN53418 , Extreme Events in Geospace: Origins, Predictability, and Consequences; 187-208
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  • 51
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    In:  CASI
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN51667 , Orbital Debris Quarterly News; 22; 1
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  • 52
    Publication Date: 2019-07-13
    Description: As the most oxidized chondrites and a group of carbonaceous chondrites spanning the range of petrologic types, CK chondrites occupy an extreme in our understanding of the origin and evolution of chondritic parent bodies. With the proposed linkage of CV and CK chondrites and the suggestion that differentiation of a postulated CV-CK asteroid could have differentiated to form a core and established a magnetic dynamo, CK chondrites are receiving considerable attention. Most of this attention has focused on the similarities between CK3 and CV3 chondrites and the origin of each. We have previously argued that melting of an oxidized core could produce a magnetite-sulfide core, rather than the more conventional metal-sulfide core. In this work, we focus on CK6 chondrites to understand the origin of the most highly metamorphosed members of the group as representative of the material that might differentiate to form such an oxidized core.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN51567 , Lunar and Planetary Science Conference; Mar 19, 2018 - Mar 23, 2018; The Woodlands, TX; United States
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  • 53
    Publication Date: 2019-07-13
    Description: This past year marked the 40th anniversary of the first Martian meteorite found in Antarctica by the ANSMET Antarctic Search for Meteorites) program, ALH 77005. Since then, an additional 14 Martian meteorites have been found by the ANSMET program making for a total of 15 Martian meteorites in the U. S. Antarctic meteorite collection at Johnson Space Center (JSC). Of the 15 meteorites, some have been paired so the 15 meteorites actually represent a total of approximately 9 separate samples. The first Martian meteorite found by ANSMET was ALH 77005 (482.500 g), a lherzolitic shergottite. When collected, this meteorite was split as a part of the joint expedition with the National Institute of Polar Research (NIPR) Japan. Originally classified as an "achondrite-unique", it was re-classified as a Martian lherzolitic shergottite in 1982. This meteorite has been allocated to 137 scientists for research and there are 180.934 g remaining at JSC. Two years later, one of the most significant Martian meteorites of the collection at JSC was found at Elephant Moraine, EET 79001 (7942.000 g), a shergottite. This meteorite is the largest in the Martian collection at JSC and was the largest stony meteorite sample collected during the 1979 season. In addition to its size, this meteorite is of particular interest because it contains a linear contact separating two different igneous lithologies, basaltic and olivine-phyric. EET 79001 has glass inclusions that contain noble gas and nitrogen compositions that are proportionally identical to the Martian atmosphere, as measured by the Viking spacecraft. This discovery helped scientists to identify where the "SNC" meteorite suite had originated, and that we actually possessed Martian samples. This meteorite has been allocated to 205 scientists for research and 5,298.435 g of sample is available.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN51557 , Lunar and Planetary Science Conference; Mar 19, 2018 - Mar 23, 2018; The Woodlands, TX; United States
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  • 54
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Space Sciences (General)
    Type: MSFC-E-DAA-TN53102 , Osher Life-Long-Learning Institute Eclipse Class; Feb 20, 2018; Huntsville, AL; United States
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  • 55
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Space Sciences (General)
    Type: MSFC-E-DAA-TN51427 , American Astronomical Society Meeting; Jan 08, 2018 - Jan 12, 2018; National Harbor, MD; United States
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  • 56
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Space Sciences (General)
    Type: MSFC-E-DAA-TN63732 , 2018 AGU Fall Meeting; Dec 10, 2018 - Dec 14, 2018; Washington, DC; United States
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  • 57
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Space Sciences (General)
    Type: MSFC-E-DAA-TN62316 , Solar Dynamics Observatory (SDO) Workshop, Catalyzing Solar Connections; Oct 29, 2018 - Nov 02, 2018; Ghent; Belgium
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  • 58
    Publication Date: 2019-07-13
    Description: The Space Physics Archive Search and Extract Consortium has developed and implemented the SPASE Data Model that provides a common language for registering a wide range of Heliophysics data and other products. The Data Model enables discovery and access tools such that any researcher can obtain data easily, thereby facilitating research, including on space weather. The Data Model includes descriptions of Simulation Models and Numerical Output, pioneered by the Integrated Medium for Planetary Exploration (IMPEx) group in Europe, and subsequently adopted by the Community Coordinated Modeling Center (CCMC). The SPASE group intends to register all relevant Heliophysics data resources, including space-, ground-, and model-based. Substantial progress has been made, especially for space-based observational data and associated observatories, instruments, and display data. Legacy product registrations and access go back more than 50 years. Real-time data will be included. The National Aeronautics and Space Administration (NASA) portion of the SPASE group has funding that assures continuity in the upkeep of the Data Model and aids with adding new products. Tools are being developed for making and editing data descriptions. Digital Object Identifiers (DOIs) for Data Products can now be included in the descriptions. The data access that SPASE facilitates is becoming more uniform, and work is progressing on Web Service access via a standard Application Programming Interface. The SPASE Data Model is stable; changes over the past 9 years were additions of terms and capabilities that are backward compatible. This paper provides a summary of the history, structure, use, and future of the SPASE Data Model.
    Keywords: Space Sciences (General)
    Type: GSFC-E-DAA-TN65482 , Space Weather (ISSN 1539-4956) (e-ISSN 1542-7390); 16; 12; 1899-1911
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  • 59
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    In:  CASI
    Publication Date: 2019-07-13
    Description: A plenary talk for the International Conference on Space Optics (ICSO)
    Keywords: Space Sciences (General)
    Type: GSFC-E-DAA-TN61734 , ICSO 2018: International Conference on Space Optics; Oct 09, 2018 - Oct 12, 2018; Chania; Greece
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  • 60
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    In:  CASI
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Space Sciences (General)
    Type: MSFC-E-DAA-TN60068 , InSightLaunch & Science Team Meeting; Sep 24, 2018; Gratz; Austria
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  • 61
    Publication Date: 2019-07-13
    Description: The International Space Station is a "global observation and diagnosis station." It promotes international Earth observations aimed at understanding and resolving the environmental issues of our home planet. A wide variety of Earth observation payloads can be attached to the exposed facilities on the station's exterior as well as within the Destiny module. The presence of a human crew also provides a unique capability for real-time observation of the Earth, and "on the fly" data collection using hand-held digital cameras, and the astronauts may also provide input to ground personnel programming the station's automated Earth observation systems. Several instruments are currently collecting data from the International Space Station; in addition, some instruments have completed their data collection missions, with other remote sensing systems in development or proposed by researchers from the partner countries, NASA, academic institutions, and corporations. The existing international partnerships, fundamental to the International Space Station, facilitate data sharing that can benefit people around the world and promote international collaboration on other Earth observation activities. The station contributes to humanity by collecting data on global climate, environmental change, and natural hazards using its unique complement of crew-operated and automated Earth observation payloads.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN58472 , Expo-Sciences Latin America 2018; Jul 02, 2018 - Jul 06, 2018; Antofagasta; Chile
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  • 62
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Space Sciences (General)
    Type: MSFC-E-DAA-TN61192 , SPIE Optics and Photonics Conference; Aug 19, 2018 - Aug 23, 2018; San Diego, CA; United States
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  • 63
    Publication Date: 2019-07-13
    Description: A test campaign was conducted placing meteorites in the 60 MW plasma Arcjet Interaction Heating Facility at NASA Ames Research Center, with the aim to achieve flight-relevant conditions for asteroid impacts in Earth's atmosphere and to provide insight into how meteoritic materials respond to extreme entry heating environments. The test conditions at heat flux of 4000 W/m2 and 140 kPa stagnation pressure are comparable to those experienced by a 30-meter diameter asteroid moving at 20 km/s velocity at 65 km altitude in the Earth's atmosphere. Test objects were a stony type H5 ordinary chondrite (Tamdakht) and an iron type IAB-MG meteorite (Campo Del Cielo), and included the terrestrial analogs Dense Flood Basalt and Fused Silica. All samples were exposed for only a few seconds in the plasma stream. Significant melt flow and vaporization was observed for both the stony and iron meteorites during exposure. Mass loss from spallation of fragments was also observed. Vapor emitted atomic lines from alkali metals and iron, but did not emit the expected MgO molecular band emissions. The meteoritic melts flowed more rapidly, indicating lower viscosity, than those of Fused Silica. The surface recession was mapped. The effective heat of ablation derived from this showed that ablation under these conditions occurred in the melt-dominated regime. Ablation parameters have an effect on ground damage estimates. A bias in ablation parameters towards the melt-dominated regime would imply that impacting asteroids survive to lower altitude, and therefore could possibly have airbursts with a larger ground damage footprint.
    Keywords: Space Sciences (General)
    Type: ARC-E-DAA-TN58379 , AIAA Aviation and Aeronautics Forum (Aviation 2018); Jun 25, 2018 - Jun 29, 2018; Atlanta, GA; United States
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  • 64
    Publication Date: 2019-07-13
    Description: The National Aeronautics and Space Administration's Additive Construction with Mobile Emplacement (ACME) project is developing construction materials with which infrastructure elements, including habitats, will be additively constructed for planetary surface missions. These materials must meet requirements such as the ability to be produced from available in-situ resources to eliminate the cost of launching materials from Earth, the ability to be emplaced via three dimensional building techniques, the ability to resist aging in extreme environments including radiation and micrometeorite bombardment, and the ability to provide the necessary structural integrity for a given building. This paper reviews the constraints placed on such planetary construction materials and details the work of the ACME team in characterizing materials that could one day construct planetary surface structures on Mars or the Moon. Material compositions, compressive strength, and requirements for additive construction on planetary surfaces are discussed. Due to the multifunctional requirements of the material, an optimization is necessary to balance between the site-specific regolith composition, emplacement via additive construction techniques, and characteristics of the final structure.
    Keywords: Space Sciences (General)
    Type: MSFC-E-DAA-TN47553 , ASCE Earth and Space Conference; Apr 09, 2018 - Apr 12, 2018; Cleveland, OH; United States
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  • 65
    Publication Date: 2019-07-13
    Description: The Centennial Challenges (CC) program, part of NASA's Space Technology Mission Directorate (STMD), was founded upon the principle that engaging the public at large was a very important part of garnering the true magnitude of grassroots American innovation and ingenuity. The program uses a focused problem-statement approach to obtain solutions and/or stimulate innovation in key NASA technology gaps by catalyzing sources outside of the traditional aerospace community. The CC program announced the first two challenge competitions in 2005 incentivizing the public to participate using a congressionally authorized prize purse. Since then, the program has developed and executed more than 18 competitions and has awarded over $9 million in prize money. The challenges have covered a variety of technology areas, including propulsion, robotics, communications and navigation, human health, science instrumentation, nanotech, materials and structures, and aerodynamics. Centennial Challenges' accomplishments from October 2016 to December 2017--including significant increases in the amount and diversity of participants; increase in prize purse awards; strong alignments with NASA missions; and partnerships with industry, academia, and other government agencies-are summarized in this paper. Technological advancements, communication strategies, and legal authority are also discussed. NASA is leading the government agencies in the area of prizes and competitions to push technologies, and the CC program is one powerful example of NASA's continuing commitment to technological advancement and innovation through non-traditional programs. Currently, the Agency has in place the proven infrastructure, policies, and people needed to enable the successful use of competition tools, including the ones used as part of the CC program.
    Keywords: Space Sciences (General)
    Type: MSFC-E-DAA-TN60002 , Space and Astronautics Forum (AIAA SPACE Forum); Sep 17, 2018 - Sep 19, 2018; Orlando, FL; United States
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  • 66
    Publication Date: 2019-07-13
    Description: Permanently shadowed craters at the lunar poles contain water, ~5 wt% according to LCROSS. Interest in water for ISRU applications. Desire to 'ground truth' water using surface prospecting; e.g. Resource Prospector (RP) & RESOLVE. How to access subsurface water resources and accurately measure quantity; Excavation operations and exposure to lunar environment may affect the results A series a ground based dirty thermal vacuum tests are being conducted to better understand the subsurface sampling operations: Sample removal and transfer, Volatiles loss during sampling operations, Concept of operations, Instrumentation. This presentation covers: The capabilities of the VF-13 Thermal Vacuum Chamber (Tvac). The Resource Prospector TVAC hardware. The summary and results of 5 years of RP volatiles tests; 43 viable samples
    Keywords: Space Sciences (General)
    Type: GRC-E-DAA-TN54729 , American Society of Civil Engineers (ASCE) Earth and Space Conference; Apr 09, 2018 - Apr 12, 2018; Cleveland, OH; United States
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  • 67
    Publication Date: 2019-07-13
    Description: In this response, we address the three main comments by Tsurutani et al. (2018, http://doi.org/10.1002/2017JA024779) namely, unusually high plasma density, interplanetary magnetic field intensity, and fast storm recovery phase. The authors agree that there is room to improve the modeling by taking into account these comments and other aspects that were not fully explored during our initial work. We are already in the process of undertaking a more comprehensive modeling project.
    Keywords: Space Sciences (General)
    Type: GSFC-E-DAA-TN58274 , Journal of Geophysical Research: Space Physics (ISSN 2169-9402) (e-ISSN 2169-9402); 123; 2; 1393-1395
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  • 68
    Publication Date: 2019-07-13
    Description: The light curves of Type IIn supernovae are dominated by the radiative energy released through the interaction of the supernova shock waves with their dense circumstellar medium (CSM). The ultraluminous Type IIn supernova SN2010jl exhibits an infrared emission component that is in excess of the extrapolated UV-optical spectrum as early as few weeks postexplosion. This emission has been considered by some as evidence for the rapid formation of dust in the cooling postshock CSM. We investigate the physical processes that may inhibit or facilitate the formation of dust in the CSM. When only radiative cooling is considered, the temperature of the dense shocked gas rapidly drops below the dust condensation temperature. However, by accounting for the heating of the postshock gas by the downstream radiation from the shock, we show that dust formation is inhibited until the radiation from the shock weakens as it propagates into the less dense outer regions of the CSM. In SN2010jl, dust formation can therefore only commence after day 380. Only the IR emission since that epoch can be attributed to the newly formed CSM dust. Observations on day 460 and later show that the IR luminosity exceeds the UV-optical luminosity. The postshock dust cannot extinct the radiation emitted by the expanding SN shock. Therefore, its IR emission must be powered by an interior source, which we identify as the reverse shock propagating through the SN ejecta. IR emission before day 380 must therefore be an IR echo from preexisting CSM dust.
    Keywords: Space Sciences (General)
    Type: GSFC-E-DAA-TN57318 , The Astrophysical Journal (ISSN 0004-637X) (e-ISSN 1538-4357); 859; 1; 66
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  • 69
    Publication Date: 2019-07-13
    Description: Lunar meteorite NWA 11421 is provisionally placed with the "NWA 8046 clan" of similar stones (the "Algerian Megafind") of which at least 33 kg has been recovered. NWA 11421 and pairs are feldspathic regolith breccias, with angular fragments of plagioclase-rich clasts in a dark glassy matrix. Most members of this clan contain 〈 5.5% FeO and 〈 0.3 ppm Th. To date, there have been no petrographic studies reported of these lunar meteorites. An 11.7 gm sample of NWA 11421 was purchased from Marcin Cimala, holder of the main mass - this sample is consistent in all respects with the formal meteorite description. This particular sample was selected because it appeared to contain a fragment of dunite.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN56817 , Annual Meeting of The Meteoritical Society; Jul 22, 2018 - Jul 27, 2018; Moscow; Russia
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  • 70
    Publication Date: 2019-07-13
    Description: We interpret recent observations of the secondary dust ejecta cloud around the Moon from the Lunar Dust Experiment (LDEX) on board the NASA Lunar Atmosphere and Dust Environment Explorer (LADEE) spacecraft with help from dynamical models of meteoroids. Results suggest that in order to match the spatial structure of observed ejecta profiles, the flux of meteoroids on the Moon must be primarily provided by short-period comets with an excess ratio of at least 1.3:1 compared to long-period comets. This ratio increases significantly if the dependence of the ejecta yield on impactor velocity is stronger than generally believed. The model accounts for the orbital geometry of LADEE and shows no indication of a large asymmetry in the meteoroid flux impacting from the Helion and Anti-Helion directions.
    Keywords: Space Sciences (General)
    Type: GSFC-E-DAA-TN58279 , Geophysical Research Letters (ISSN 0034-4257) (e-ISSN 1879-0704); 45; 4; 1713-1722
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  • 71
    Publication Date: 2019-07-13
    Description: The Wang-Sheeley-Arge (WSA)-ENLIL+Cone model is used extensively in space weather operations world-wide to model coronal mass ejection (CME) propagation. As such, it is important to assess its performance. We present validation results of the WSA-ENLIL+Cone model installed at the Community Coordinated Modeling Center (CCMC) and executed in real-time by the CCMC space weather team. CCMC uses the WSA-ENLIL+Cone model to predict CME arrivals at NASA missions throughout the inner heliosphere. In this work we compare model predicted CME arrival-times to in situ interplanetary coronal mass ejection leading edge measurements at Solar TErrestrial RElations Observatory-Ahead (STEREO-A), Solar TErrestrial RElations Observatory-Behind (STEREO-B), and Earth (Wind and ACE) for simulations completed between March 2010 and December 2016 (over 1,800 CMEs). We report hit, miss, false alarm, and correct rejection statistics for all three locations. For all predicted CME arrivals, the hit rate is 0.5, and the false alarm rate is 0.1. For the 273 events where the CME was predicted to arrive at Earth, STEREO-A, or STEREO-B, and was actually observed (hit event), the mean absolute arrival-time prediction error was 10.4 +/- 0.9 h, with a tendency to early prediction error of -4.0 h. We show the dependence of the arrival-time error on CME input parameters. We also explore the impact of the multi-spacecraft observations used to initialize the model CME inputs by comparing model verification results before and after the STEREO-B communication loss (since September 2014) and STEREO-A sidelobe operations (August 2014- December 2015). There is an increase of 1.7 h in the CME arrival time error during single, or limited two-viewpoint periods, compared to the three-spacecraft viewpoint period. This trend would apply to a future space weather mission at L5 or L4 as another coronagraph viewpoint to reduce CME arrival time errors compared to a single L1 viewpoint.
    Keywords: Space Sciences (General)
    Type: GSFC-E-DAA-TN58268 , Journal of Space Weather and Space Climate (e-ISSN 2115-7251); 8; A17
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  • 72
    Publication Date: 2019-07-13
    Description: One of the key problems in planetary science is the identification of the building blocks of Earth, and whether they exist within our current collection of meteorites. Stable mass independent isotopic anomalies, usually nucleosynthetic in origin, are a key tool in fingerprinting material coming from different accretionary regions within the protoplanetary disk. For a number of isotopic systems such as O, Ni, Ti and Cr, enstatite chondrites (EC) appear to be the strongest candidates for Earth's building blocks, despite their low Mg/Si ratios relative to the bulk Earth. It has been proposed that Earth, the Moon-forming impactor and enstatite chondrites all were originally sourced from the same reservoir in the protoplanetary disk, but subsequently experienced divergent chemical evolution pathways. This was recently challenged by who used the correlation between Mo and Nd isotopes in bulk meteorites to argue that such a reservoir does not exist as the isotopic composition of enstatite chondrites is resolvable from Earth. However, in detail the Nd isotopic ratios of EC ((142)Nd/(144)Nd, (148)Nd/(144)Nd, (150)Nd/(144)Nd) show considerable variability, and overlap significantly with the isotopic composition of both the bulk Earth and ordinary chondrites (OC). previously identified Nd isotopic variability in EC, linking it to the degree of equilibration the meteorite had experienced, however they only focused on collecting high precision (142)Nd/(144)Nd, which also has contributions from the decay of the short-lived Sm-146 nuclide (t(sub 1/2) ~103 Myr), making identification of nucleosynthetic anomalies less clear. While the study of reports all the Nd isotopic ratios measured at high precision, only equilibrated EC were analyzed. Therefore, with the currently published data it is unclear to what extent thermal equilibration in the EC is responsible for the variation observed in the stable Nd isotopic ratios, and whether the EC reservoir can be resolved from Earth. In order to better understand the genetic relationship between enstatite chondrites and the Earth we are carrying out a more systematic study including both equilibrated and unequilibrated enstatite chondrites, focusing on high precision analysis of all the stable Nd isotopic ratios.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN48811 , Women in Planetary Science and Exploration; Feb 17, 2018 - Feb 18, 2018; Toronto; Canada
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  • 73
    Publication Date: 2019-07-13
    Description: The Habitable Exoplanet Observatory Mission (HabEx) is one of four missions under study for the 2020 Astrophysics Decadal Survey. Its goal is to directly image and spectroscopically characterize planetary systems in the habitable zone around nearby sun-like stars. Additionally, HabEx will perform a broad range of general astrophysics science enabled by 100 to 2500 nm spectral range and 3 x 3 arc-minute FOV. Critical to achieving the HabEx science goals is a large, ultra-stable UV/Optical/Near-IR (UVOIR) telescope. The baseline HabEx telescope is a 4-meter off-axis unobscured three-mirror-anastigmatic, diffraction limited at 400 nm with wavefront stability on the order of a few 10s of picometers. This paper summarizes the opto-mechanical design of the HabEx baseline optical telescope assembly, including a discussion of how science requirements drive the telescope's specifications, and presents analysis that the baseline telescope structure meets its specified tolerances.
    Keywords: Space Sciences (General)
    Type: MSFC-E-DAA-TN58729 , SPIE Astronomical Telescopes + Instrumentation; Jun 10, 2018 - Jun 15, 2018; Austin, TX; United States|Space Telescopes and Instrumentation 2018: Optical, Infrared, and Millimeter Wave; 10698; 106980W
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  • 74
    Publication Date: 2019-07-13
    Description: We examine the mechanisms responsible for the dropout of energetic electron flux during 31 May to 1 June 2013 using Van Allen Probe (Radiation Belt Storm Probes (RBSP)) electron flux data and simulations with the Comprehensive Inner Magnetosphere-Ionosphere (CIMI) model. During the storm main phase, L-shells at RBSP locations are greater than ~8, which are connected to open drift shells. Consequently, diminished electron fluxes were observed over a wide range of energies. The combination of drift shell splitting, magnetopause shadowing, and drift loss all results in butterfly electron pitch angle distributions (PADs) at the nightside. During storm sudden commencement, RBSP observations display electron butterfly PADs over a wide range of energies. However, it is difficult to determine whether there are butterfly PADs during the storm main phase since the maximum observable equatorial pitch angle from RBSP is not larger than ~40 during this period. To investigate the causes of the dropout, the CIMI model is used as a global 4-D kinetic inner magnetosphere model. The CIMI model reproduces the dropout with very similar timing and flux levels and PADs along the RBSP trajectory for 593 keV. Furthermore, the CIMI simulation shows butterfly PADs for 593 keV during the storm main phase. Based on comparison of observations and simulations, we suggest that the dropout during this event mainly results from magnetopause shadowing.
    Keywords: Space Sciences (General)
    Type: GSFC-E-DAA-TN58324 , Journal of Geophysical Research: Space Physics (ISSN 2169-9402) (e-ISSN 2169-9402); 123; 2; 1178-1190
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  • 75
    Publication Date: 2019-07-13
    Description: Recent studies suggest that the hydrogen (H) density in the exosphere and geocorona might differ from previously assumed values by factors as large as 2. We use the SAMI3 (Sami3 is Also a Model of the Ionosphere) and Comprehensive Inner Magnetosphere-Ionosphere models to evaluate scenarios where the hydrogen density is reduced or enhanced, by a factor of 2, relative to values given by commonly used empirical models. We show that the rate of plasmasphere refilling following a geomagnetic storm varies nearly linearly with the hydrogen density. We also show that the ring current associated with a geomagnetic storm decays more rapidly when H is increased. With respect to these two space weather effects, increased exosphere hydrogen density is associated with reduced threats to space assets during and following a geomagnetic storm.
    Keywords: Space Sciences (General)
    Type: GSFC-E-DAA-TN58333 , Space Weather (ISSN 1539-4956) (e-ISSN 1542-7390); 16; 3; 205-215
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  • 76
    Publication Date: 2019-07-13
    Description: This work presents a space climatology timeline ranging from the Big Bang to the present. It begins with a description of the early universe including the origin and abundances of particles significant for radiation effects. It continues to a transition period to modern times when the era of modern space climatology began to emerge due to discoveries of sunspots and the solar activity cycle, along with development of early astronomical methods. The timeline concludes in the modern era with a description of the radiation environments of galactic cosmic rays, solar particle events and the Van Allen Belts.
    Keywords: Space Sciences (General)
    Type: GSFC-E-DAA-TN58572 , IEEE Nuclear and Space Radiation Effects Conference (NSREC); Jul 17, 2018 - Jul 20, 2018; Kona, HI; United States
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  • 77
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    In:  CASI
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Space Sciences (General)
    Type: MSFC-E-DAA-TN58660 , International LISA Symposium; Jul 08, 2018 - Jul 13, 2018; Chicago, IL; United States
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  • 78
    Publication Date: 2019-07-13
    Description: The Astromaterials Acquisition and Cura-tion Office at NASA's Johnson Space Center (hereafter JSC curation) is the past, present, and future home of all of NASA's astromaterials sample collections. JSC curation currently houses all or part of nine different sample collections. Our primary goals are to maintain the long-term integrity of the samples and ensure that the samples are distributed for scientific study in a fair, timely, and responsible manner, thus maximizing the return on each sample. Part of the curation process is planning for the future, thus we also perform funda-mental research in advanced curation initiatives. Ad-vanced Curation is tasked with developing procedures, technology, and data sets necessary for curating new types of sample collections, or getting new results from existing sample collections [1]. As part of these ad-vanced curation efforts we are augmenting our analyti-cal facilities.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN54726 , PSIDA (Planetary Science Informatics and Data Analytics); Apr 24, 2018 - Apr 26, 2018; St Louis, MO; United States
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  • 79
    Publication Date: 2019-07-13
    Description: A test campaign was conducted placing meteorites in the 60 MW plasma Arcjet Interaction Heating Facility at NASA Ames Research Center, with the aim to achieve flight-relevant conditions for asteroid impacts in Earth's atmosphere and to provide insight into how meteoritic materials respond to extreme entry heating environments. The test conditions at heat flux of 4000 W/m2 and 140 kPa stagnation pressure are comparable to those experienced by a 30-meter diameter asteroid moving at 20 km/s velocity at 65 km altitude in the Earth's atmosphere. Test objects were a stony type H5 ordinary chondrite (Tamdakht) and an iron type IAB-MG meteorite (Campo Del Cielo), and included the terrestrial analogs Dense Flood Basalt and Fused Silica. All samples were exposed for only a few seconds in the plasma stream. Significant melt flow and vaporization was observed for both the stony and iron meteorites during exposure. Mass loss from spallation of fragments was also observed. Vapor emitted atomic lines from alkali metals and iron, but did not emit the expected MgO molecular band emissions. The meteoritic melts flowed more rapidly, indicating lower viscosity, than those of Fused Silica. The surface recession was mapped. The effective heat of ablation derived from this showed that ablation under these conditions occurred in the melt-dominated regime. Ablation parameters have an effect on ground damage estimates. A bias in ablation parameters towards the melt-dominated regime would imply that impacting asteroids survive to lower altitude, and therefore could possibly have airbursts with a larger ground damage footprint.
    Keywords: Space Sciences (General)
    Type: ARC-E-DAA-TN56553 , AIAA Aviation and Aeronautics Forum (Aviation 2018); Jun 25, 2018 - Jun 29, 2018; Atlanta, GA; United States
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  • 80
    Publication Date: 2019-07-13
    Description: Recent observations have revealed that many solar coronal jets involve the eruption of miniature versions of large-scale filaments. Such ''mini-filaments'' are observed to form along the polarity inversion lines of strong, magnetically bipolar regions embedded in open (or distantly closing) unipolar field. During the generation of the jet, the filament becomes unstable and erupts. Recently we described a model for these mini-filament jets, in which the well-known magnetic-breakout mechanism for large-scale coronal mass ejections is extended to these smaller events. In this work we use 3D magnetohydrodynamic simulations to study in detail three realizations of the model. We show that the breakout-jet generation mechanism is robust and that different realizations of the model can explain different observational features. The results are discussed in relation to recent observations and previous jet models.
    Keywords: Space Sciences (General)
    Type: GSFC-E-DAA-TN53850 , The Astrophysical Journal (ISSN 0004-637X) (e-ISSN 1538-4357); 852; 2; 98
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  • 81
    Publication Date: 2019-07-13
    Description: Mars has been the target for future human exploration for decades. However, even after the successes of the orbital, lander, and rover missions, there are still an array of unknowns that pose potential physical, chemical, and biological hazards to human health from the martian environment. Mars sample return represents a vital next step in understanding these hazards and mitigating the risks to both the ex-plorers and the inhabitants of Earth.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN52559 , International Mars Sample Return Conference; Apr 25, 2018 - Apr 27, 2018; Berlin; Germany
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  • 82
    Publication Date: 2019-07-13
    Description: Subaerial environments of interest for Mars Sample Return include surface or near-surface sites not covered by a body of water, but having direct access to water from precipitation, snow melt, or ambient-temperature groundwater. This includes soils, wetlands, ephemeral ponds, cold springs, and periglacial/glacial environments, with paleosol profiles as a high priority collection site. Such soils can be topped by aqueously deposited sediments and precipitates from wetlands, ephemeral ponds, and springs. The composition and morphology of paleosols preserve evidence of past climate, aqueous conditions, and life. Key topics addressed by samples collected from subaerial environments include: 1) Constrain the duration of interaction with liquid water by investigating a weathering profile from the surface to unaltered parent material. 2) Assess the characteristics of past liquid water, and how it has changed through time. 3) Investigate weathered materials such as soils, paleosols, sediments, weathering rinds or rock coatings to assess past climate. 4) Examine characteristics of past aeolian and atmospheric processes.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN52587 , International Mars Sample Return Conference; Apr 25, 2018 - Apr 27, 2018; Berlin; Germany
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  • 83
    Publication Date: 2019-07-13
    Description: Considerable recent planning has focused on the potential importance of Mars in-situ resources to support future human missions. While atmospheric CO2 provides a source of oxygen, the regolith offers other potential resources. The most significant surface asset is water, which could be used for propellant generation, life support, habitat sustainment, and agriculture. In regard to the latter, the regolith could also provide a source of nutrients to supplement terrestrial fertilizers and/or act as a substrate to buffer plant roots. Local material could also be used as feedstock for construction, including for structures, roads, and additive manufacturing. Native salts (e.g. perchlorates or chlorides) in the Martian regolith could be used as water absorbents for closed loop life support systems or for capture of the limited atmospheric water.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN52613 , International Mars Sample Return Conference; Apr 25, 2018 - Apr 27, 2018; Berlin; Germany
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  • 84
    Publication Date: 2019-07-13
    Description: A biosignature (''definitive biosignature'' or DBS) is an object, substance and/or pattern whose origin specifically requires a biological agent. One category of DBS are complex organic molecules and/or structures whose formation and abundances relative to other compounds are virtually unachievable in the absence of life. A potential biosignature (PBS) is an object, substance and/or pattern that might have a biological origin and thus compels investigators to gather more data before reaching a conclusion as to the presence or absence of life. The usefulness of a PBS is determined not only by the probability that life created it but also by the improbability that nonbiological processes produced it. Because habitable planetary environments create nonbiological features that can mimic biosignatures, these environments must be characterized to the extent necessary to provide a context that is essential for confirming the presence of DBS. Environmental conditions also must have allowed biosignatures to be preserved and amenable to detection. Categories of biosignatures and their measurement requirements are indicated below.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN52590 , International Mars Sample Return Conference; Apr 25, 2018 - Apr 27, 2018; Berlin; Germany
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  • 85
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    In:  CASI
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Space Sciences (General)
    Type: M18-6527 , Lecture to the Applied Materials Processing class at the University of Alabama; Feb 26, 2018; Huntsville, AL; United States
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  • 86
    Publication Date: 2019-07-13
    Description: Moon Burst Energetics All-sky Monitor (MoonBEAM) is a CubeSat concept of deploying gamma-ray detectors in cislunar space to improve localization precision for gamma-ray bursts by utilizing the light travel time difference between a spacecraft in Earth and cislunar orbit. MoonBEAM is designed with high TRL components to be flight ready. This instrument would probe the extreme processes in cosmic collision of compact objects and facilitate multi-messenger time-domain astronomy to explore the end of stellar life cycles and black hole formations.
    Keywords: Space Sciences (General)
    Type: MSFC-E-DAA-TN53283 , High Energy Astrophysics in the 2020''s and Beyond; Mar 18, 2018 - Mar 21, 2018; Rosemont, IL; United States
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  • 87
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    In:  CASI
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Space Sciences (General)
    Type: MSFC-E-DAA-TN53820 , Sustain Space Chamber Award Winners; Mar 14, 2018; Huntsville, AL; United States
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  • 88
    Publication Date: 2019-07-13
    Description: The Imaging X-ray Polarimetry Explorer (IXPE) project is an international collaboration to build and fly a polarization sensitive X-ray observatory. The IXPE Observatory consists of the spacecraft and payload. The payload is composed of three X-ray telescopes, each consisting of a mirror module optical assembly and a polarization-sensitive X-ray detector assembly; a deployable boom maintains the focal length between the optical assemblies and the detectors. The goal of the IXPE Mission is to provide new information about the origins of cosmic X-rays and their interactions with matter and gravity as they travel through space. IXPE will do this by exploiting its unique capability to measure the polarization of X-rays emitted by cosmic sources. The collaboration for IXPE involves national and international partners during design, fabrication, assembly, integration, test, and operations. The full collaboration includes NASA Marshall Space Flight Center (MSFC), Ball Aerospace, the Italian Space Agency (ASI), the Italian Institute of Astrophysics and Space Planetology (IAPS)/Italian National Institute of Astrophysics (INAF), the Italian National Institute for Nuclear Physics (INFN), the University of Colorado (CU) Laboratory for Atmospheric and Space Physics (LASP), Stanford University, McGill University, and the Massachusetts Institute of Technology. The goal of this paper is to discuss risk management as it applies to the IXPE project. The full IXPE Team participates in risk management providing both unique challenges and advantages for project risk management. Risk management is being employed in all phases of the IXPE Project, but is particularly important during planning and initial execution-the current phase of the IXPE Project. The discussion will address IXPE risk strategies and responsibilities, along with the IXPE management process which includes risk identification, risk assessment, risk response, and risk monitoring, control, and reporting.
    Keywords: Space Sciences (General)
    Type: MSFC-E-DAA-TN50587 , IEEE Aerospace Conference; Mar 03, 2018 - Mar 10, 2018; Big Sky, MT; United States
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  • 89
    Publication Date: 2019-07-13
    Description: August 21, 2017 provided a unique opportunity to investigate the effects of the total solar eclipse on high frequency (HF) radio propagation and ionospheric variability. In Marshall Space Flight Center's partnership with the US Space and Rocket Center (USSRC) and Austin Peay State University (APSU), we engaged citizen scientists and students in an investigation of the effects of an eclipse on the mid-latitude ionosphere. Activities included fieldwork and station-based data collection of HF Amateur Radio frequency bands and VLF radio waves before, during, and after the eclipse to build a continuous record of changing propagation conditions as the moon's shadow marched across the United States. Post-eclipse radio propagation analysis provided insights into ionospheric variability due to the eclipse.
    Keywords: Space Sciences (General)
    Type: MSFC-E-DAA-TN55029 , Space Weather Workshop; Apr 16, 2018 - Apr 20, 2018; Westminister, CO; United States
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  • 90
    Publication Date: 2019-07-13
    Description: The Goddard Earth Observing System (GEOS) atmospheric model and data assimilation system are used to perform an Observing System Simulation Experiment (OSSE) for the proposed MISTiC Wind mission. The GEOS OSSE includes a reference simulation (the Nature Run), from which the pseudo-observations are generated. These pseuo-observations span the entire suite of in-situ and space space-based observations presently used in operational weather prediction, with the addition of the MISTiC-Wind dataset. New observation operators have been constructed for the MISTiC Wind data, including both the radiances measured in the 4-micron part of the solar spectrum and the winds derived from these radiances. The OSSE examines the impacts on global forecast skill of adding these observations to the current operational suite, showing substantial improvements in forecasts when the wind information are added. It is shown that a constellation of four MISTiC Wind satellites provides more benefit than a single platform, largely because of the increased accuracy of the feature-derived wind measurements when more platforms are used.
    Keywords: Space Sciences (General)
    Type: GSFC-E-DAA-TN52845 , Working Group on Space-Based Lidar Winds; Feb 07, 2018 - Feb 08, 2018; Boulder, CO; United States
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  • 91
    Publication Date: 2019-07-13
    Description: We describe a probe-class mission concept that provides an unprecedented view of the X-ray sky, performing timing and 0.2-30 keV spectroscopy over timescales from microseconds to years. The Spectroscopic Time-Resolving Observatory for Broadband Energy X-rays (STROBE-X) comprises three primary instruments. The first uses an array of lightweight optics (3-m focal length) that concentrate incident photons onto solid state detectors with CCD-level (85-130 eV) energy resolution, 100 ns time resolution, and low background rates to cover the 0.2-12 keV band. This technology is scaled up from NICER [1], with enhanced optics to take advantage of the longer focal length of STROBE-X. The second uses large-area collimated silicon drift detectors, developed for ESA's LOFT [2], to cover the 2-30 keV band. These two instruments each provide an order of magnitude improvement in effective area compared with its predecessor (NICER and RXTE, respectively). Finally, a sensitive sky monitor triggers pointed observations, provides high duty cycle, high time resolution, high spectral resolution monitoring of the X-ray sky with approx. 20 times the sensitivity of the RXTE ASM, and enables multi-wavelength and multi-messenger studies on a continuous, rather than scanning basis. For the first time, the broad coverage provides simultaneous study of thermal components, non-thermal components, iron lines, and reflection features from a single platform for accreting black holes at all scales. The enormous collecting area allows detailed studies of the dense matter equation of state using both thermal emission from rotation-powered pulsars and harder emission from X-ray burst oscillations. The combination of the wide-field monitor and the sensitive pointed instruments enables observations of potential electromagnetic counterparts to LIGO and neutrino events. Additional extragalactic science, such as high quality spectroscopy of clusters of galaxies and unprecedented timing investigations of active galactic nuclei, is also obtained
    Keywords: Space Sciences (General)
    Type: MSFC-E-DAA-TN50652 , American Astronomical Society (AAS) Meeting; Jan 08, 2018 - Jan 12, 2018; National Harbor, MD; United States
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  • 92
    Publication Date: 2019-07-13
    Description: We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 m and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg2 field-of-view Wide Field Instrument. Potential ground- breaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations.
    Keywords: Space Sciences (General)
    Type: GSFC-E-DAA-TN65937 , Journal of Astronomical Telescopes, Instruments, and Systems (ISSN 2329-4124) (e-ISSN 2329-4221); 4; 3; 034003
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  • 93
    Publication Date: 2019-07-13
    Description: Solar active regions (ARs) contain the brightest and hottest coronal EUV (Extreme Ultra-Violet) loops - the core of an AR is typically the brightest structure inside the AR. In the present work we report fine-scale transient brightenings and flows in the coolest loops (the counterpart of chromospheric arch filament systems long observed in H-alpha filtergrams of bipolar emerging flux regions) seen in the core of an AR observed in 172 angstroms by Hi-C2.1 (High Resolution Coronal Imager, version 2.1). Some of these are rooted, at one of their feet, in mixed-polarity field in the photosphere. We complement the 5-min Hi-C2.1 data with SDO/AIA/HMI (Solar Dynamics Observatory / Atmospheric Imaging Assembly / Helioseismic and Magnetic Imager) and IRIS SJ (Interface Region Imaging Spectrograph Slit-Jaw) images and spectral data, and examine fine-scale events, flows and their photospheric magnetic field. We find counter streaming flows in the arch filament system, similar to that long observed in filaments. There are scattered fine-scale brightening events. Most, if not all, of these brightenings are at sites of converging opposite-polarity magnetic flux (implying flux cancellation, sometimes resulting from flux emergence). The fine-scale flows stem from some of the brightenings. Flux cancellation at these sites apparently results in fine-scale explosions that drive the counter streaming flows. In the IRIS spectra, we look for evidence of upflows from brightenings at ends of loops of the arch filament system.
    Keywords: Space Sciences (General)
    Type: MSFC-E-DAA-TN63874 , American Geophysical Union Fall Meeting (AGU 2018); Dec 10, 2018 - Dec 14, 2018; Washington, DC; United States
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  • 94
    Publication Date: 2019-07-13
    Description: Laboratory studies of lunar apatite [Ca5(PO4)3(F,Cl,OH)] have been important for determining the volatile inventory of the interior and the roles volatiles played during the magmatic evolution of the Moon. It has been suggested that high-Ti mare basalts sample volatiles from a distinct reservoir in the lunar mantle. However, there is still debate surrounding the crystallization and post-crystallization history of apatite in those basalts. This information is required before we can use apatite to characterize the abundance or isotopic composition of volatiles in melts or magmatic source regions. Our goal is to investigate the mineral chemistry, crystal structure, and volatile inventory of phosphates in high-Ti basalts from Apollo 11, which will allow us to determine the crystallization history of apatite in these rocks and identify any potential secondary processes that have changed the volatile composition that apatite acquired from the melt.
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN54438 , Microscopy & Microanalysis 2018; Aug 05, 2018 - Aug 09, 2018; Baltimore, MD; United States
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  • 95
    Publication Date: 2019-07-13
    Description: The water-soluble organic compounds in carbonaceous chondrite meteorites constitute a record of the synthetic reactions occurring at the birth of the solar system and those taking place during parent body alteration and may have been important for the later origins and development of life on Earth. In this present work, we have developed a novel methodology for the simultaneous analysis of the molecular distribution, compound-specific (delta)(exp 13)C, and enantiomeric compositions of aliphatic monocarboxylic acids (MCA) extracted from the hot-water extracts of 16 carbonaceous chondrites from CM, CR, CO, CV, and CK groups. We observed high concentrations of meteoritic MCAs, with total carbon weight percentages which in some cases approached those of carbonates and insoluble organic matter. Moreover, we found that the concentration of MCAs in CR chondrites is higher than in the other meteorite groups, with acetic acid exhibiting the highest concentration in all samples. The abundance of MCAs decreased with increasing molecular weight and with increasing aqueous and/or thermal alteration experienced by the meteorite sample. The (delta)(exp 13)C isotopic values of MCAs ranged from 52 to +27(0/00), and aside from an inverse relationship between (delta)(exp 13)C value and carbon straight-chain length for C3C6 MCAs in Murchison, the 13C-isotopic values did not correlate with the number of carbon atoms per molecule. We also observed racemic compositions of 2-methylbutanoic acid in CM and CR chondrites. We used this novel analytical protocol and collective data to shed new light on the prebiotic origins of chondritic MCAs.
    Keywords: Space Sciences (General)
    Type: GSFC-E-DAA-TN63129 , Meteoritics & Planetary Science (ISSN 1086-9379) (e-ISSN 1945-5100); 54; 2; 415-430
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  • 96
    Publication Date: 2019-07-13
    Description: The September 10 2017 X8 flare was one of the biggest of the current solar cycle, and it was also incredibly well observed. This presentation will review the available XRT data for this flare. XRT observed the initial flux rope eruption, which was also well observed by AIA and SUVI. XRT data is missing for some of the impulsive phase of the flare, but the late phase shows some very interesting features. There is some nice XRT imaging of a plasma sheet above cusp-shaped loops between 16:47 and 18:39 UT. After 18:40 UT, a double loop structure becomes apparent, with a more rounded loop nested within a larger, cusp-shaped structure. The flare loops continue to grow, and at around 1 UT on September 11, supra-arcade down flows and shrinking loops become visible. There is also interesting data in the late phase of this flare from RHESSI and the Expanded Owens Valley Solar Array (EOVSA).
    Keywords: Space Sciences (General)
    Type: MSFC-E-DAA-TN61065 , Hinode-12 Science Meeting; Sep 10, 2018 - Sep 13, 2018; Granada; Spain
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  • 97
    Publication Date: 2019-07-13
    Description: The highly favorable 2017 apparition of 2P/Encke allowed the first comprehensive comparison of primary volatile abundances in a given comet across multiple apparitions. This apparition offered opportunities to address pressing questions in cometary science, including investigating evolutionary and/or heliocentric distance (R(sub h)) effects on volatile production, sampling the hypervolatiles CO and CH4 in an ecliptic comet, and measuring volatile release at small R(sub h). The faintness and frequently low geocentric velocity of ecliptic comets during most apparitions make our near-infrared observations of these hypervolatiles rare and of high scientific impact. We characterized the volatile composition of 2P/Encke on three post-perihelion dates using the iSHELL spectrograph at the NASA Infrared Telescope Facility on Maunakea, HI. We detected fluorescent emission from nine primary volatiles (H2O, CO, C2H6, CH3OH, CH4, H2CO, NH3, OCS, and HCN) and three fragment species (OH*, NH2, and CN), and obtained a sensitive upper limit for C2H2. We report rotational temperatures, production rates, and mixing ratios (abundances relative to H2O). Compared to mean abundances in comets observed to date in the near-infrared, mixing ratios of trace gases in 2P/Encke were depleted for all species except H2CO and NH3, which were normal. The detection of the hypervolatiles CO and CH4 is particularly notable given the paucity of measurements in ecliptic comets. We observed significant differences in primary volatile composition compared to published pre-perihelion results from 2003 at larger R(sub h). We discuss possible mechanisms for these differences and discuss these results in the context of findings from the Rosetta mission and ground-based studies of comets.
    Keywords: Space Sciences (General)
    Type: GSFC-E-DAA-TN64587 , The Astronomical Journal (ISSN 0004-6256) (e-ISSN 1538-3881); 156; 6; 251
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  • 98
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    In:  CASI
    Publication Date: 2019-07-13
    Description: At the Harsh Environment Mass Spectrometer workshop we focus on bringing the Mass spectrometer to the sample because it's not practical to bring the samples back to the laboratories. However there are many NASA mass spectrometer applications where we bring the samples to the instrument. This presentation will discuss some of those applications that are ripe for innovative instrument development.
    Keywords: Space Sciences (General)
    Type: KSC-E-DAA-TN61874 , Harsh-Environment Mass Spectrometry Workshop; Oct 16, 2018 - Oct 18, 2018; Cologne; Germany
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  • 99
    Publication Date: 2019-07-13
    Description: The concept of 'phase heritage' (e.g., Timms et al., 2017a) involves microstructural recognition of the former presence of a phase that has since transformed to another via evidence encoded in crystallographic orientations. Phase heritage relies on the phenomenon that newly grown (daughter) phases nucleate with particular crystallographic orientation relationships with the preceding (parent) phase. This phenomenon is common for displacive (i.e., shear or martensitic) transformations, well documented in the metals and ceramics literature, but is relatively uncommon in geosciences. This presentation outlines the concepts behind this approach, showcases results from software for automated analysis of EBSD data, and illustrates examples of polymorphic and dissociation phase transformations in the ZrSiO4-ZrO2-SiO2 system, which has particularly useful applications for 'extreme thermobarometry' in impact environments (Timms et al., 2017a).
    Keywords: Space Sciences (General)
    Type: JSC-E-DAA-TN60138 , TIGeR Conference 2018; Sep 09, 2018; Perth, WA; Australia
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  • 100
    Publication Date: 2019-07-13
    Description: This presentation examines how problem solving was done on the NEEMO 22 Mission and whether human autonomy teaming would be able to assist in the type of troubleshooting that was conducted by Mission Control.
    Keywords: Space Sciences (General)
    Type: ARC-E-DAA-TN61013 , Website content for Human Autonomy TIM; Sep 14, 2018; Moffett Field, CA; United States
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