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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 379 records · Page 21
All sourcesNASA NTRSDOE OSTI
NASA NTRS2014

Decarboxylation of Carbon Compounds as a Potential Source for CO2 and CO Observed by SAM at Yellowknife Bay, Gale Crater, Mars

Martian carbon was detected in the Sheepbed mudtsone at Yellowknife Bay, Gale Crater, Mars by the Sample Analysis at Mars (SAM) instrument onboard Curiosity, the rover of the Mars Science Laboratory missio]. The carbon was detected as CO2 thermally evolved from drilled and sieved rock powder that was delivered to SAM as a <150-micron-particle- size fraction. Most of the CO2 observed in the Cumberland (CB) drill hole evolved between 150deg and 350deg C. In the John Klein (JK) drill hole, the CO2 evolved up to 500deg C. Hypotheses for the source of the the CO2 include the breakdown of carbonate minerals reacting with HCl released from oxychlorine compounds, combustion of organic matter by O2 thermally evolved from the same oxychlorine minerals, and the decarboxylation of organic molecules indigenous to the martian rock sample. Here we explore the potential for the decarboxylation hypothesis.

Eigenbrode, J. L.↗
NASA NTRS2018

Soil Mixing with Steam and Zero Valent Iron Remediation Performance Monitoring Results at Wilson Corner, Kennedy Space Center, Florida

The National Aeronautics and Space Administration (NASA), Kennedy Space Center (KSC), Remediation Program implemented a groundwater interim measure between September 2014 and February 2015, to remediate a trichloroethene (TCE) groundwater source area at the Wilson Corners site. The groundwater plume is associated with the release of chlorinated solvents (specifically TCE) from historic precision cleaning and laboratory operations. A summary of the groundwater interim measure using soil mixing with steam and zero valent iron (also referred to as large diameter auger [LDA]) was presented at the 2015 Florida Remediation Conference. The objective of this presentation is to provide performance monitoring results.

Chrest, Anne M.↗
NASA NTRS2019

Daily evaluation of 26 precipitation datasets using Stage-IV gauge-radar data for the CONUS

New precipitation (P) datasets are released regularly, following innovations in weather forecasting models, satellite retrieval methods, and multi-source merging techniques. Using the conterminous US as a case study, we evaluated the performance of 26 gridded (sub-)daily P datasets to obtain insight into the merit of these innovations. The evaluation was performed at a daily timescale for the period 2008–2017 using the Kling–Gupta efficiency (KGE), a performance metric combining correlation, bias, and variability. As a reference, we used the high-resolution (4 km) Stage-IV gauge-radar P dataset. Among the three KGE components, the P datasets performed worst overall in terms of correlation (related to event identification). In terms of improving KGE scores for these datasets, improved P totals (affecting the bias score) and improved distribution of P intensity (affecting the variability score) are of secondary importance. Among the 11 gauge-corrected P datasets, the best overall performance was obtained by MSWEP V2.2, underscoring the importance of applying daily gauge corrections and accounting for gauge reporting times. Several uncorrected P datasets outperformed gauge-corrected ones. Among the 15 uncorrected P datasets, the best performance was obtained by the ERA5-HRES fourth-generation reanalysis, reflecting the significant advances in earth system modeling during the last decade. The (re)analyses generally performed better in winter than in summer, while the opposite was the case for the satellite-based datasets. IMERGHH V05 performed substantially better than TMPA-3B42RT V7, attributable to the many improvements implemented in the IMERG satellite P retrieval algorithm. IMERGHH V05 outperformed ERA5-HRES in regions dominated by convective storms, while the opposite was observed in regions of complex terrain. The ERA5-EDA ensemble average exhibited higher correlations than the ERA5-HRES deterministic run, highlighting the value of ensemble modeling. The WRF regional convection-permitting climate model showed considerably more accurate P totals over the mountainous west and performed best among the uncorrected datasets in terms of variability, suggesting there is merit in using high-resolution models to obtain climatological P statistics. Our findings provide some guidance to choose the most suitable P dataset for a particular application.

Hylke E. Beck↗
NASA NTRSDate not supplied

Continuing Global SO2 Data Record from OMI and SNPP/OMPS to JPSS-1/NOAA-20/OMPS

Since 2004, the Ozone Monitoring Instrument (OMI) aboard NASA's Earth Observing System (EOS) Aura spacecraft has been providing global observations that help to constrain the sources, transport, and environmental impacts of anthropogonic and volcanic SO2. The OMI SO2 data record is now being continued with the NASA/NOAA Suomi National Polar-orbiting Partnership (SNPP)/Ozone Mapping and Profiler Suite (OMPS) launched in 2011. Both OMI and SNPP/OMPS SO2 products are produced with the Goddard principal component analysis (PCA) based spectral fitting algorithm. This data-driven technique inherently accounts for various instrumental factors and geophysical interferences, leading to high-quality, consistent SO2 retrievals between OMI and SNPP/OMPS, despite coarser spectral (~0.5 nm vs. ~1 nm) and spatial (13  24 km2 vs. 50  50 km2 at nadir) resolution for the latter. In this presentation, we describe our effort to continue the long-term SO2 climate data record using measurements from the Joint Polar Satellite System (JPSS)-1/NOAA-20 (N20)/OMPS. Launched in 2017, the N20/OMPS is a follow-on for SNPP/OMPS but features a spatial resolution (17  13 km2) that is comparable with OMI. We will discuss our progress implementing the PCA SO2 algorithm with N20/OMPS, especially algorithmic improvements to further reduce retrieval noise and bias for large volcanic eruptions. We will present examples for both continuously emitting sources (e.g., power plants in India and oil/gas fields in the Middle East) and volcanic eruptions (e.g., Raikoke in 2019). We will also compare N20/OMPS SO2 retrievals with OMI and SNPP/OMPS, as well as other instruments such as the ESA Copernicus Sentinel-5 Precursor (S5P)/TROPOspheric Monitoring Instrument (TROPOMI). To assess the ability of N20/OMPS to monitor and quantify SO2 sources, we will run the level 2 retrievals through a top-down emission algorithm to estimate the SO2 emission strengths for a number of point sources. Finally, we will outline our plan for further algorithm refinement and public data release.

SO2↗
NASA NTRS1979

Gaseous halos - Implications for cluster, galaxy, and radio-source evolution

Substantial amounts of enriched gas produced during the early stages of galactic evolution can be stably contained within massive extended halos and released into the intracluster medium by galaxy collisions at a relatively late epoch. If most of the intracluster gas in rich clusters originates in this manner, the onset of ram-pressure stripping can be delayed until z is no more than about 0.5. Prior to this, such clusters contain many spiral and gas-rich elliptical galaxies, thereby accounting for the unusually large proportion of blue galaxies found in distant clusters. Implications are drawn for X-ray observations of rich clusters and for the morphology of extended extragalactic radio sources.

Norman, C.↗
NASA NTRS2016

SpIES: The Spitzer IRAC Equatorial Survey

We describe the first data release from the Spitzer-IRAC Equatorial Survey (SpIES); a large-area survey of approx.115 sq deg in the Equatorial SDSS Stripe 82 field using Spitzer during its "warm" mission phase. SpIES was designed to probe sufficient volume to perform measurements of quasar clustering and the luminosity function at z > or = 3 to test various models for "feedback" from active galactic nuclei (AGNs). Additionally, the wide range of available multi-wavelength, multi-epoch ancillary data enables SpIES to identify both high-redshift (z > or = 5) quasars as well as obscured quasars missed by optical surveys. SpIES achieves 5 sigma depths of 6.13 μJy (21.93 AB magnitude) and 5.75 μJy (22.0 AB magnitude) at 3.6 and 4.5 microns, respectively-depths significantly fainter than the Wide-field Infrared Survey Explorer (WISE). We show that the SpIES survey recovers a much larger fraction of spectroscopically confirmed quasars (approx.98%) in Stripe 82 than are recovered by WISE (∼55%). This depth is especially powerful at high-redshift (z > or = 3.5), where SpIES recovers 94% of confirmed quasars, whereas WISE only recovers 25%. Here we define the SpIES survey parameters and describe the image processing, source extraction, and catalog production methods used to analyze the SpIES data. In addition to this survey paper, we release 234 images created by the SpIES team and three detection catalogs: a 3.6 microns only detection catalog containing approx. 6.1 million sources, a 4.5 microns only detection catalog containing approx. 6.5 million sources, and a dual-band detection catalog containing approx. 5.4 million sources.

quasar clustering↗
NASA NTRS2006

Solar Activity and Solar Eruptions

Our Sun is a dynamic, ever-changing star. In general, its atmosphere displays major variation on an 11-year cycle. Throughout the cycle, the atmosphere occasionally exhibits large, sudden outbursts of energy. These "solar eruptions" manifest themselves in the form of solar flares, filament eruptions, coronal mass ejections (CMEs), and energetic particle releases. They are of high interest to scientists both because they represent fundamental processes that occur in various astrophysical context, and because, if directed toward Earth, they can disrupt Earth-based systems and satellites. Research over the last few decades has shown that the source of the eruptions is localized regions of energy-storing magnetic field on the Sun that become destabilized, leading to a release of the stored energy. Solar scientists have (probably) unraveled the basic outline of what happens in these eruptions, but many details are still not understood. In recent years we have been studying what triggers these magnetic eruptions, using ground-based and satellite-based solar observations in combination with predictions from various theoretical models. We will present an overview of solar activity and solar eruptions, give results from some of our own research, and discuss questions that remain to be explored.

Sterling, Alphonse C.↗
NASA NTRS1975

Application of vascular aquatic plants for pollution removal, energy and food production in a biological system

Vascular aquatic plants such as water hyacinths (Eichhornia crassipes) (Mart.) Solms and alligator weeds (Alternanthera philoxeroides) (Mart.) Griesb., when utilized in a controlled biological system (including a regular program of harvesting to achieve maximum growth and pollution removal efficiency), may represent a remarkably efficient and inexpensive filtration and disposal system for toxic materials and sewage released into waters near urban and industrial areas. The harvested and processed plant materials are sources of energy, fertilizer, animal feed, and human food. Such a system has industrial, municipal, and agricultural applications.

Wolverton, B. C.↗
NASA NTRS1978

Infrared, optical, and X-ray properties of the nuclei of nearby galaxies

The paper considers nuclear activity of galaxies and models for violent activity and surveys observations that the nucleus of almost every galaxy is able to release energy in many exotic forms. Observations of galaxies characterized by obscured nuclei, powerful infrared sources, or ejection of large gas masses from nuclei are described. It is suggested that, although the nucleus is active for a large fraction of the life of the galaxy, it may, for long periods operate at a low level of activity.

Burbidge, G.↗
NASA NTRS1984

Chronology of KSC and KSC related events, 1982

The history of activities at the Kennedy Space Center in 1982 is presented as reflected in NASA News Releases and selected periodicals. Items are arranged in chronological order by date of the published sources. Actual data date of the event may be indicated in parenthesis when the article itself does not make that information explicit. Highlights of the year's activities include three launchings of the orbiter Columbia; successful launches of communications satellites using expendable vehicles; major changes in contracting; and the selection of a base operations contractor.

Nail, K., Jr.↗
NASA NTRS1983

New fireworthy composites for use in transportation vehicles

This paper presents an overview of certain aspects of the evaluation of the fireworthiness of air transport interiors. It examines some technical opportunities that are available today through the modification of aircraft interior subsystem components, modifications that may reasonably be expected to provide improvements in aircraft fire safety. These modifications have the potential of reducing the rate of fire growth, with a consequent reduction of heat, toxic gas, and smoke emission throughout the habitable interior of an aircraft, whatever the initial source of the fire. It is shown that these new materials modifications reduce the fire hazard not only because of their unique ablative properties, which help to contain or isolate the fire source, but also because there is a significant reduction in their characteristic flame spread, heat release, and smoke and toxic gas emissions.

Parker, J. A.↗
NASA NTRS1986

The two states of Cyg X-1 and related sources

The model for active galactic nuclei of Kazanas and Ellison (1986a), employing quasi-spherical accretion onto a black hole, when scaled down to solar mass objects, provides a straightforward account of the bimodal spectral behavior of Cyg X-1 and the other galactic black hole candidates. It is argued that the change in the spectrum is due to the drastic increase of the source compactness with the accretion rate and the subsequent conversion of most of the energy released by accretion into e(+)e(-) pairs. It is also argued that similar changes may be observed in active galactic nuclei.

Kazanas, D.↗
NASA NTRS1989

Summary and evaluation of the Strategic Defense Initiative Space Power Architecture Study

The Space Power Architecture Study (SPAS) identified and evaluated power subsystem options for multimegawatt electric (MMWE) space based weapons and surveillance platforms for the Strategic Defense Initiative (SDI) applications. Steady state requirements of less than 1 MMWE are adequately covered by the SP-100 nuclear space power program and hence were not addressed in the SPAS. Four steady state power systems less than 1 MMWE were investigated with little difference between them on a mass basis. The majority of the burst power systems utilized H(2) from the weapons and were either closed (no effluent), open (effluent release) or steady state with storage (no effluent). Closed systems used nuclear or combustion heat source with thermionic, Rankine, turboalternator, fuel cell and battery conversion devices. Open systems included nuclear or combustion heat sources using turboalternator, magnetohydrodynamic, fuel cell or battery power conversion devices. The steady state systems with storage used the SP-100 or Star-M reactors as energy sources and flywheels, fuel cells or batteries to store energy for burst applications. As with other studies the open systems are by far the lightest, most compact and simplist (most reliable) systems. However, unlike other studies the SPAS studied potential platform operational problems caused by effluents or vibration.

Edenburn, M.↗
NASA NTRS2002

Remote Sensing and Geochemistry of Planetary Surfaces

We have been examining the resources required to support potential life on Mars, as a way of understanding the possible abundance and distribution of life. Based on our understanding of the Earth, the necessary requirements for the environment to allow it to support life are (i) presence of liquid water, (ii) access to the biogenic elements (C, H, O, N, S, P, Ca, Fe, etc.), and (iii) a source of energy to drive chemical disequilibrium, such that the reactions back toward equilibrium can release energy to support metabolism. While even demonstrating that all of these requirements have been met would not mean that life would necessarily exist on Mars, they provide the context in which a search for life or analysis of geochemical characteristics that might be indicative of life might be carried out. Our previous work has focused on the first and third of these characteristics determine where and when liquid water might have been present, and understanding the availability of chemical energy from weathering reactions that might ID support life. In the analysis supported by this grant (covering the time period 2/15/01-2/14/02), we have been examining the second requirement--the abundance of the necessary biogenic elements, their geographical distribution on Mars and the information on the possible vertical distribution within the crust, and their geochemical accessibility and mobility within the crust and at the surface. In particular, our work during the performance period has emphasized phosphorous.

Jakosky, Bruce M.↗
NASA NTRS2004

Luminous Binary Supersoft X-Ray Sources

This has been a remarkably productive year. We have completed an algorithm to select SSSs in external galaxies which have been observed by Chandru or XMM-Newton. By applying this algorithm to new data, we have discovered an extension of the class of SSSs to sources that are somewhat harder (100 - 300 eV, instead of tens of eV), but which are nevertheless much softer than canonical X-ray sources. We have completed a study of SSSs in M31 and have also considered several other galaxies. From these studies, some population characteristics are beginning to emerge; these provide clues to the natures of the systems. We have considered ultraluminous SSSs in M1O1 and NGC 300. It is possible that these may correspond to accreting intermediate-mass black holes, rather than accreting white dwarfs. We have also studied individual systems, such as CAL 83, and have followed up on additional sources in fields we have studied, such as in the galaxy NGC 1313. NASA has released a press release on some of our work.

DiStefano, Rosanne↗
NASA NTRS2010

Designing and Implementing an OVERFLOW Reader for ParaView and Comparing Performance Between Central Processing Units and Graphical Processing Units

In the Applied Aerosciences and CFD branch at Johnson Space Center, computational simulations are run that face many challenges. Two of which are the ability to customize software for specialized needs and the need to run simulations as fast as possible. There are many different tools that are used for running these simulations and each one has its own pros and cons. Once these simulations are run, there needs to be software capable of visualizing the results in an appealing manner. Some of this software is called open source, meaning that anyone can edit the source code to make modifications and distribute it to all other users in a future release. This is very useful, especially in this branch where many different tools are being used. File readers can be written to load any file format into a program, to ease the bridging from one tool to another. Programming such a reader requires knowledge of the file format that is being read as well as the equations necessary to obtain the derived values after loading. When running these CFD simulations, extremely large files are being loaded and having values being calculated. These simulations usually take a few hours to complete, even on the fastest machines. Graphics processing units (GPUs) are usually used to load the graphics for computers; however, in recent years, GPUs are being used for more generic applications because of the speed of these processors. Applications run on GPUs have been known to run up to forty times faster than they would on normal central processing units (CPUs). If these CFD programs are extended to run on GPUs, the amount of time they would require to complete would be much less. This would allow more simulations to be run in the same amount of time and possibly perform more complex computations.

Chawner, David M.↗
NASA NTRS2015

Using Satellite Observations to Evaluate the AeroCOM Volcanic Emissions Inventory and the Dispersal of Volcanic SO2 Clouds in MERRA

Simulation of volcanic emissions in climate models requires information that describes the eruption of the emissions into the atmosphere. While the total amount of gases and aerosols released from a volcanic eruption can be readily estimated from satellite observations, information about the source parameters, like injection altitude, eruption time and duration, is often not directly known. The AeroCOM volcanic emissions inventory provides estimates of eruption source parameters and has been used to initialize volcanic emissions in reanalysis projects, like MERRA. The AeroCOM volcanic emission inventory provides an eruptions daily SO2 flux and plume top altitude, yet an eruption can be very short lived, lasting only a few hours, and emit clouds at multiple altitudes. Case studies comparing the satellite observed dispersal of volcanic SO2 clouds to simulations in MERRA have shown mixed results. Some cases show good agreement with observations Okmok (2008), while for other eruptions the observed initial SO2 mass is half of that in the simulations, Sierra Negra (2005). In other cases, the initial SO2 amount agrees with the observations but shows very different dispersal rates, Soufriere Hills (2006). In the aviation hazards community, deriving accurate source terms is crucial for monitoring and short-term forecasting (24-h) of volcanic clouds. Back trajectory methods have been developed which use satellite observations and transport models to estimate the injection altitude, eruption time, and eruption duration of observed volcanic clouds. These methods can provide eruption timing estimates on a 2-hour temporal resolution and estimate the altitude and depth of a volcanic cloud. To better understand the differences between MERRA simulations and volcanic SO2 observations, back trajectory methods are used to estimate the source term parameters for a few volcanic eruptions and compared to their corresponding entry in the AeroCOM volcanic emission inventory. The nature of these mixed results is discussed with respect to the source term estimates.

OMI SO2↗
NASA NTRS2018

Exoplanet Biosignatures: Understanding Oxygen as a Biosignature in the Context of Its Environment

Here we review how environmental context can be used to interpret whether O 2 is a biosignature in extrasolar planetary observations. This paper builds on the overview of current biosignature research discussed in Schwieterman et al. (2017), and provides an in-depth, interdisciplinary example of biosignature identification and observation that serves as a basis for the development of the general framework for biosignature assessment described in Catling et al., (2017). O 2 is a potentially strong biosignature that was originally thought to be an unambiguous indicator for life at high-abundance. In exploring O 2 as a biosignature, we describe the coevolution of life with the early Earth's environment, and how the interplay of sources and sinks in the planetary environment may have resulted in suppression of O 2 release into the atmosphere for several billion years, a false negative for biologically generated O 2 . False positives may also be possible, with recent research showing potential mechanisms in exoplanet environments that may generate relatively high abundances of atmospheric O 2 without a biosphere being present. These studies suggest that planetary characteristics that may enhance false negatives should be considered when selecting targets for biosignature searches. Similarly our ability to interpret O 2 observed in an exoplanetary atmosphere is also crucially dependent on environmental context to rule out false positive mechanisms. We describe future photometric, spectroscopic and time-dependent observations of O 2 and the planetary environment that could increase our confidence that any observed O 2 is a biosignature, and help discriminate it from potential false positives. The rich, interdisciplinary study of O 2 illustrates how a synthesis of our understanding of life's evolution and the early Earth, scientific computer modeling of star-planet interactions and predictive observations can enhance our understanding of biosignatures and guide and inform the development of next-generation planet detection and characterization missions. By observing and understanding O 2 in its planetary context we can increase our confidence in the remote detection of life, and provide a model for biosignature development for other proposed biosignatures.

Victoria S Meadows↗