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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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1980

Earth survey applications division: Research leading to the effective use of space technology in applications relating to the Earth's surface and interior

Accomplishments and future plans are described for the following areas: (1) geology - geobotanical indicators and geopotential data; (2) modeling magnetic fields; (3) modeling the structure, composition, and evolution of the Earth's crust; (4) global and regional motions of the Earth's crust and earthquake occurrence; (5) modeling geopotential from satellite tracking data; (6) modeling the Earth's gravity field; (7) global Earth dynamics; (8) sea surface topography, ocean dynamics; and geophysical interpretation; (9) land cover and land use; (10) physical and remote sensing attributes important in detecting, measuring, and monitoring agricultural crops; (11) prelaunch studies using LANDSAT D; (12) the multispectral linear array; (13) the aircraft linear array pushbroom radiometer; and (14) the spaceborne laser ranging system.

Carpenter, L.↗
NASA NTRS1984

Continental and oceanic crustal magnetization modelling

Inversion of magnetic data from the MAGSAT satellite, to arrive at intensities of magnetization of the Earth's crust, was performed by two different methods. The first method uses a spherical harmonic model of the magnetic field. The coefficients believed to represent sources in the Earth's crust can then be inverted to arrive at vertical dipole moments per unit area at the Earth's surface. The spherical harmonic models contain coefficients of degrees of harmonics up to 23. The dipole moment per unit area for a surface element can then be determined by summing the contribution for each individual degree of harmonic. The magnetic moments were calculated for continental and oceanic areas separately as well as over certain latitudinal segments. Of primary concern was to determine whether there are any differences between continental and oceanic areas. The second analysis with magnetization intensities was made using narrower ranges of degrees of harmonics, assuming that higher degrees are present in the core field signal.

Harrison, C. G. A.↗
NASA NTRS2004

Near Space Tracking of the EM Phenomena Associated with the Main Earthquakes

Searching for electromagnetic (EM) phenomena originating in the Earth's crust prior to major earthquakes (M>5) are the object of this exploratory study. We present the idea of a possible relationship between: (1) electro-chemical and thermodynamic processes in the Earth's crust and (2) ionic enhancement of the atmosphere/ionosphere with tectonic stress and earthquake activity. The major source of these signals are proposed to originate from electromagnetic phenomenon which are responsible for these observed pre-seismic processes, such as, enhanced IR emission, also born as thermal anomalies, generation of long wave radiation, light emission caused by ground-to-air electric discharges, Total Electron Content (TEC) ionospheric anomalies and ionospheric plasma variations. The source of these data will include: (i) ionospheric plasma perturbations data from the recently launched DEMETER mission and currently available TEC/GPS network data; (ii) geomagnetic data from ORSTED and CHAMP; (iii) Thermal infra-red (TIR) transients mapped by the polar orbiting (NOAA/AVHRR, MODIS) and (iv) geosynchronous weather satellites measurements of GOES, METEOSAT. This approach requires continues observations and data collecting, in addition to both ground and space based monitoring over selected regions in order to investigate the various techniques for recording possible anomalies. During the space campaign emphasis will be on IR emission, obtained from TIR (thermal infrared) satellites, that records land/sea surface temperature anomalies and changes in the plasma and total electron content (TEC) of the ionosphere that occur over areas of potential earthquake activity.

Ouzounov, Dimitar↗
NASA NTRS1981

A proposal to conduct a Caribbean plate project involving the application of space technology to the study of Caribbean geology

The Caribbean plate project is designed to improve current understanding of geological resources and geological hazards within the Caribbean region. Models of mineral occurrence and genesis (including energy resources) on a regional scale, which contribute to nonrenewable resource investigations. Models of lithospheric stress and strain on a regional scale, which contribute to forecasting geological hazards such as earthquakes and major volcanic eruptions are developed. Geological information is synthesize, and research tools provided by space technology the study of the Earth's crust are used. The project was organized in a thematic fashion, to focus on specific geological aspects of the Caribbean plate which are considered to be key factors in developing the types of models described. The project adopts a synoptic perspective in seeking to characterize the three dimensional structure, composition, state of stress, and evolution of the entire Caribbean plate. Geological information derived from analysis of space acquired data is combined with information provided by conventional methods to obtain insight into the structure, composition, and evolution of the Earth's crust. In addition, very long baseline interferometry and laser ranging techniques, which are also based upon the use of space technology, obtain information concerning crustal motion that, in turn, provides insight into the distribution and localization of crustal stress.

Wadge, G.↗
NASA NTRS1989

Stable carbon and sulfur isotopes as records of the early biosphere

The abundance ratios of the stable isotopes of light elements such as carbon and sulfur can differ between various naturally-occurring chemical compounds. If coexisting compounds have achieved mutual chemical and isotopic equilibrium, then the relative isotopic composition can record the conditions at which equilibrium was last maintained. If coexisting chemical compounds indeed formed simultaneously but had not achieved mutual equilibrium, then their relative isotopic compositions often reflect the conditions and mechanisms associated with the kinetically controlled reactions responsible for their production. In the context of Mars, the stable isotopic compositions of various minerals might record not only the earlier environmental conditions of the planet, but also whether or not the chemistry of life ever occurred there. Two major geochemical reservoirs occur in Earth's crust, both for carbon and sulfur. In rocks formed in low temperature sedimentary environments, the oxidized forms of these elements tend to be enriched in the isotope having the larger mass, relative to the reduced forms. In sediments where the organics and sulfides were formed by biological processes, these isotopic contrasts were caused by the processes of biological CO2 fixation and dissimilatory sulfate reduction. Such isotopic contrasts between oxidized and reduced forms of carbon and sulfur are permitted by thermodynamics at ambient temperatures. However, nonbiological chemical reactions associated with the production of organic matter and the reduction of organics and sulfides are extremely slow at ambient temperatures. Thus the synthesis of organics and sulfides under ambient conditions illustrates life's profound role as a chemical catalyst that has altered the chemistry of Earth's crust. Because the stable isotopes of carbon and sulfur can reflect their chemistry, they are useful probes of the Martian surface.

Desmarais, David J.↗
NASA NTRS1985

Anorthositic oceanic crust in the Archean Earth

Ultrapure minerals separated from eclogite inclusions in kimberlites were analyzed for Sm, Nd, Sr, and oxygen isotopes and for major and trace elements. Clinopyroxene (cpx) and garnet (gnt) are the only primary mineral phases in these rocks, and mineral phases and their alteration products. The WR sub calc. is the reconstructed bulk composition excluding all the contamination influences. Two groups of eclogites: are distinguished: (1) type A Noritic-anorthositic eclogites; and (2) type B Ti-ferrogabbroic eclogites. The oxygen isotopes are primary mantle-derived features of these rocks and are not caused by posteruption processes, as they were measured on unaltered, clean mineral separates and show a correlation with REE pattern and Sr and Nd isotopes. It is suggested that the variation of the oxygen isotopes are caused by crustal-level fluid-rock interaction at relatively low temperature. It is shown that oxygen isotopes variation in MORB basalts caused by the hydrothermal system are in the same range as the observed oxygen isotope variation in eclogites. A model to explain the new set of data is proposed. It is thought that some of these eclogites might be emplaced into the upper lithosphere or lower crust at the time corresponding to their internal isochron age. The calculated WR composition was used to estimate model ages for these rocks.

Jagoutz, E.↗
NASA NTRS1980

Magsat investigation

A computer program was prepared for modeling segments of the Earth's crust allowing for heterogeneity in magnetization in calculating the Earth's field at Magsat heights. This permits investigation of a large number of possible models in assessing the magnetic signatures of subprovinces of the Canadian shield. The fit between the model field and observed fields is optimized in a semi-automatic procedure.

Hall, D. H.↗
NASA NTRS1991

Report of the panel on earth rotation and reference frames, section 7

Objectives and requirements for Earth rotation and reference frame studies in the 1990s are discussed. The objectives are to observe and understand interactions of air and water with the rotational dynamics of the Earth, the effects of the Earth's crust and mantle on the dynamics and excitation of Earth rotation variations over time scales of hours to centuries, and the effects of the Earth's core on the rotational dynamics and the excitation of Earth rotation variations over time scales of a year or longer. Another objective is to establish, refine and maintain terrestrial and celestrial reference frames. Requirements include improvements in observations and analysis, improvements in celestial and terrestrial reference frames and reference frame connections, and improved observations of crustal motion and mass redistribution on the Earth.

Dickey, Jean O.↗
NASA NTRS1992

Carbon isotope evidence for the stepwise oxidation of the Proterozoic environment

The oxidation of the earth's crust and the increase in atmospheric oxygen early in earth history have been linked to the accumulation of reduced carbon in sedimentary rocks. Trends in the carbon isotope composition of sedimentary organic carbon and carbonate show that during the Proterozoic aeon (2.5-0.54 Gyr ago) the organic carbon reservoir grew in size, relative to the carbonate reservoir. This increase, and the concomitant release of oxidizing power in the environment, occurred mostly during episodes of global rifting and orogeny.

Des Marais, David J.↗
NASA NTRS1992

Carbon Isotope Evidence for the Stepwise Oxidation of the Proterozoic Environment

The oxidation of the Earth's crust and the increase in atmospheric oxygen early in Earth history have been linked to the accumulation of reduced carbon in sedimentary rocks. Trends in the carbon isotope composition of sedimentary organic carbon and carbonate show that during the Proterozoic aeon (2.5-0.54 Gyr ago) the organic carbon reservoir grew in size, relative to the carbonate reservoir. This increase, and the concomitant release of oxidizing power in the environment, occurred mostly during episodes of global rifting and orogeny.

DesMarais, David J.↗
NASA NTRS1963

Lunar Rocks as a Source of Oxygen

A thermodynamic study of the thermal stability of conventional terrestrial minerals in a hypothetical lunar atmosphere has opened some interesting speculation. Much of the Earth's crust is composed of oxides of silicon, aluminum, magnesium, and related compounds. These crust components may be as much a product of the Earth's atmosphere as vegetation and animal life. Though inanimate and long considered imperishable, these materials are stable under conditions of an atmosphere equivalent to 34 ft of water at sea level and persist under adverse conditions of moisture and temperature to altitudes of roughly 29,000 ft above sea level. The oxygen content averages 21% ) and the oxygen partial pressure would be roughly 1/5 atm.

Poole, H. G.↗
NASA NTRS1998

Elementary Theoretical Forms for the Spatial Power Spectrum of Earth's Crustal Magnetic Field

The magnetic field produced by magnetization in Earth's crust and lithosphere can be distinguished from the field produced by electric currents in Earth's core because the spatial magnetic power spectrum of the crustal field differs from that of the core field. Theoretical forms for the spectrum of the crustal field are derived by treating each magnetic domain in the crust as the point source of a dipole field. The geologic null-hypothesis that such moments are uncorrelated is used to obtain the magnetic spectrum expected from a randomly magnetized, or unstructured, spherical crust of negligible thickness. This simplest spectral form is modified to allow for uniform crustal thickness, ellipsoidality, and the polarization of domains by an periodically reversing, geocentric axial dipole field from Earth's core. Such spectra are intended to describe the background crustal field. Magnetic anomalies due to correlated magnetization within coherent geologic structures may well be superimposed upon this background; yet representing each such anomaly with a single point dipole may lead to similar spectral forms. Results from attempts to fit these forms to observational spectra, determined via spherical harmonic analysis of MAGSAT data, are summarized in terms of amplitude, source depth, and misfit. Each theoretical spectrum reduces to a source factor multiplied by the usual exponential function of spherical harmonic degree n due to geometric attenuation with attitude above the source layer. The source factors always vary with n and are approximately proportional to n(exp 3) for degrees 12 through 120. The theoretical spectra are therefore not directly proportional to an exponential function of spherical harmonic degree n. There is no radius at which these spectra are flat, level, or otherwise independent of n.

Voorhies, C.↗
NASA NTRS1966

Exploration geophysics

Geophysical methods for investigation of terrestrial crust and mineral prospecting

GEOPHYSICS↗
NASA NTRS1985

Biological modulation of planetary atmospheres: The early Earth scenario

The establishment and subsequent evolution of life on Earth had a profound impact on the chemical regime at the planet's surface and its atmosphere. A thermodynamic gradient was imposed on near-surface environments that served as the driving force for a number on important geochemical transformations. An example is the redox imbalance between the modern atmosphere and the material of the Earth's crust. Current photochemical models predict extremely low partial pressures of oxygen in the Earth's prebiological atmosphere. There is widespread consensus that any large-scale oxygenation of the primitive atmosphere was contingent on the advent of biological (autotrophic) carbon fixation. It is suggested that photoautotrophy existed both as a biochemical process and as a geochemical agent since at least 3.8 Ga ago. Combining the stoichiometry of the photosynthesis reaction with a carbon isotope mass balance and current concepts for the evolution of the stationary sedimentary mass as a funion of time, it is possible to quantify, the accumulation of oxygen and its photosynthetic oxidation equivalents through Earth history.

Schidlowski, M.↗
NASA NTRS2005

Comets, Carbonaceous Meteorites, and the Origin of the Biosphere

The biosphere comprises the Earth s crust, atmosphere, oceans, and ice caps and the living organisms that survive within this habitat. The discoveries of barophilic chemolithoautotrophic thermophiles living deep within the crust and in deep-sea hydrothermal vents, and psychrophiles in permafrost and deep within the Antarctic Ice Sheet indicate the Earth s biosphere is far more extensive than previously recognized. Molecular biomarkers and Bacterial Paleontology provide evidence that life appeared very early on the primitive Earth and the origin of the biosphere is closely linked with the emergence of life. The role of comets, meteorites, and interstellar dust in the delivery of water, organics and prebiotic chemicals has long been recognized. Deuterium enrichment of seawater and comets indicates that comets delivered oceans to the early Earth. Furthermore, the similarity of the D/H ratios and the chemical compositions of CI carbonaceous meteorites and comets indicate that the CI meteorites may be remnants of cometary nuclei with most volatiles removed. Comets, meteorites, and interstellar dust also contain complex organic chemicals, amino acids, macromolecules, and kerogen-like biopolymers and may have played a crucial role in the delivery of complex organics and prebiotic chemicals during the Hadean (4.5-3.8 Gyr) period of heavy bombardment. The existence of indigenous microfossils of morphotypes of cyanobacteria in the CI and CM carbonaceous meteorites suggests that the paradigm that life originated endogenously in the primitive oceans of early Earth may require re-consideration. Recent data on the hot (300-400 K) black crust on comet P/Halley and Stardust images of P/Wild 2 showing depressions, tall cliffs, and pinnacles, indicate the presence of thick, durable, dark crusts on comets. If cavities within the ice and crust sustain vapor pressures in excess of 10 millibar, then localized pools of liquid water and brines could exist within the comet. Since life exists on Earth wherever there is liquid water, it is suggested that comets might also harbour viable and/or cryopreserved microbiota.

Hoover, Richard B.↗
NASA NTRS1985

Noble gases in meteorites and terrestrial planets

Terrestrial planets and chondrites have noble gas platforms that are sufficiently alike, especially Ne/Ar, that they may have acquired their noble gases by similar processes. Meteorites presumably obtained their noble gases during formation in the solar nebula. Adsorption onto C - the major gas carrier in chondrites - is the likely mechanism for trapping noble gases; recent laboratory simulations support this hypothesis. The story is more complex for planets. An attractive possibility is that the planets acquired their noble gases in a late accreting veneer of chondritic material. In chondrites, noble gases correlate with C, N, H, and volatile metals; by Occam's Razor, we would expect a similar coupling in planets. Indeed, the Earth's crust and mantle contain chondritic like trace volatiles and PL group metals, respectively and the Earth's oceans resemble C chondrites in their enrichment of D (8X vs 8-10X of the galactic D/H ratio). Models have been proposed to explain some of the specific noble gas patterns in planets. These include: (1) noble gases may have been directly trapped by preplanetary material instead of arriving in a veneer; (2) for Venus, irradiation of preplanetary material, followed by diffusive loss of Ne, could explain the high concentration of AR-36; (3) the Earth and Venus may have initially had similar abundances of noble gases, but the Earth lost its share during the Moon forming event; (4) noble gases could have been captured by planetestimals, possibly leading to gravitational fractionation, particularly of Xe isotopes and (5) noble gases may have been dissolved in the hot outer portion of the Earth during contact with a primordial atmosphere.

Wacker, J. F.↗
NASA NTRS1992

Melting of cognetic depleted and enriched reservoirs and the production of high Ti Mare basalts

Implicit in current understanding of the location of terrestrial enriched and depleted reservoirs is the notion that they are spatially separated. The depleted reservoir on Earth is situated in the upper mantle, and the complementary enriched reservoir is located in the crust. However, Earth reservoirs are continually being modified by recycling driven by mantle convection. The Moon is demonstrably different from Earth in that its evolution was arrested relatively early - effectively with 1.5 Ga of its formation. It is possible that crystallized trapped liquids (from the late stages of a magma ocean) have been preserved as LILE-enriched portions of the lunar mantle. This would lead to depleted (cumulate) and enriched (magma ocean residual liquid) reservoirs in the lunar upper mantle. There is no evidence for significant recycling from the highland crust back into the mantle. Therefore, reservoirs created at the Moon's inception may have remained intact for over 4.0 Ga. The topics discussed include the following: (1) radiogenic isotopes in high-Ti mare basalts; (2) formation of cogenetic depleted and enriched reservoirs; and (3) melting of the source to achieve high-Ti mare basalts.

Snyder, Gregory A.↗