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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 1,531 records · Page 85
All sourcesNASA NTRSDOE OSTI
NASA NTRS1990

Space Shuttle Orbiter logistics - Managing in a dynamic environment

The importance and methods of monitoring logistics vital signs, logistics data sources and acquisition, and converting data into useful management information are presented. With the launch and landing site for the Shuttle Orbiter project at the Kennedy Space Center now totally responsible for its own supportability posture, it is imperative that logistics resource requirements and management be continually monitored and reassessed. Detailed graphs and data concerning various aspects of logistics activities including objectives, inventory operating levels, customer environment, and data sources are provided. Finally, some lessons learned from the Shuttle Orbiter project and logistics options which should be considered by other space programs are discussed.

Renfroe, Michael B.↗
NASA NTRS1990

Master data directories and Catalog Interoperability

While the 'Catalog Interoperability' (CI) project began as a NASA effort to facilitate identification, location, and access to data of interest to space and earth sciences researchers, it now has a membership encompassing numerous U.S. and international agencies as well as academic institutions. CI is creating a global network of interconnected directory, catalog, and inventory systems. Its directories contain brief summary information about data sets, and can either furnish automated links to other information systems yielding greater detail on matters of interest or indicate to whom requests for additional information can go.

Thieman, J. R.↗
NASA NTRS1989

Development of satellite remote sensing techniques as an economic tool for forestry industry

A cooperative commercial development project designed to focus on cost-effective and practical applications of satellite remote sensing in forest management is discussed. The project, initiated in September, 1988 is being executed in three phases: (1) development of a forest resource inventory and geographic information system (GIS) updating systems; (2) testing and evaluation of remote-sensing products against forest industry specifications; and (3) integration of remote-sensing services and products in an operational setting. An advisory group represented by eleven major forest-product companies will provide direct involvement of the target market. The advisory group will focus on the following questions: Does the technology work for them? How can it be packaged to provide the needed forest-management information? Can the products and information be provided in a cost-effective manner?

Sader, Steven A.↗
NASA NTRS1991

Early mantle differentiation and its thermal consequences

This paper discusses early events (i.e., pre-3.8 Ga) leading to the mantle differentiation. Arguments are presented in favor of a pre-3.8 Ga basaltic crust covering the earth to balance the depletion of the mantle source of Archean continental crust. It is shown that isotopic and chemical considerations of surviving Archean rocks require the existence of a region enriched in Nd throughout much of the early and middle Archean, which was distinct from the continental crust. Data are presented on the essential mass balance for Nd between the depleted mantle and the enriched reservoir, showing that the enriched reservoir must have contained a large (about 30-70 percent) fraction of the total Nd inventory of the differentiated crust-mantle system at 3.8 Ga.

Galer, S. J. G.↗
NASA NTRS1991

Ventilation of North Pacific Intermediate Waters - The role of the Alaskan Gyre

Hydrographic data, tritium data, and potential vorticity calculations suggest that although North Pacific Intermediate Water is formed in the northwest, the Alaskan Gyre might be an additional ventilation site. The proposed ventilation is quantified by a vertical column tritium inventory, which indicates an excess of 0.08 kg of tritium in the Alaskan Gyre. An evaluation of the energy stored in the water column and of wind and buoyancy forcing shows that during winter conditions enough energy can be pumped into the system to force 26.80 sigma(theta) to outcrop in the Alaskan Gyre. Model results suggest that relatively limited outcrops in time and space (tens of days and several hundred kilometers in diameter) can account for the excess tritium.

Van Scoy, Kim A.↗
NASA NTRS1991

Water on Mars: Clue to accretional history

Geological evidence for large amounts of water at the Martian surface appears to be in conflict with geochemical evidence from SNC meteorites that suggests that the Mars mantle is dry and should have lost almost all of its initially large inventory of water during accretion. Here, several possibilities are suggested as to how the apparently conflicting data from two sources may be reconciled. The considerations examined indicate that several plausible explanations for the apparent conflict between geochemical evidence of little water on Mars and geologic evidence of abundant water. One possible conclusion is that Mars has a primitive volatile-rich crust that has been partly overplated with young, dry, mantle-derived volcanoes of which we have samples in the SNC meteorites.

Carr, M. H.↗
NASA NTRS1991

Impact and collisional processes in the solar system

As impact cratered terrains have been successively recognized on certain planets and planetary satellites, it has become clear that impact processes are important to the understanding of the accretion and evolution of all solid planets. The noble gases in the normalized atmospheric inventories of the planets and the normalized gas content of meteorites are grossly similar, but demonstrate differences from each other which are not understood. In order to study shock devolatilization of the candidate carrier phases which are principally thought to be carbonaceous or hydrocarbons in planetesimals, experiments were conducted on noble gase implantation in various carbons: carbon black, activated charcoal, graphite, and carbon glass. These were candidate starting materials for impact devolatilization experiments. Initial experiments were conducted on vitreous amorphous carbon samples which were synthesized under vapor saturated conditions using argon as the pressurizing medium. An amino acid and surface analysis by laser ionization analyses were performed on three samples of shocked Murchison meteorite. A first study was completed in which a series of shock loading experiments on a porous limestone and on a non-porous gabbro in one and three dimensions were performed. Also a series of recovery experiments were conducted in which shocked molten basalt a 1700 C is encapsulated in molybdenum containers and shock recovered from up to 6 GPa pressures.

Ahrens, Thomas J.↗
NASA NTRS1991

Liquid annulus

It is shown that the specific impulse varies with the square root of the temperature and inversely with the square root of the molecular weight of the propellant. Typical values for specific impulse corresponding to various rocket concepts are shown. The Liquid Annulus core concept consists of a fuel element which will be arranged in a moderator block. The advantages as seen for the system are: high specific impulse; structural material will all run at low temperature; and lower fission product inventory because of evaporation. It is felt that this concept is worth at least a first look because of the promise of very high specific impulse. Because of the low thrust, one would probably need a cluster of engines. This is not necessarily bad because there would be some redundancy, but because of the low thrust one might have to refuel while running. Depending on the fuel vaporization, material can be included in the uranium that is injected as one is running along.

Ludewig, Hans↗
NASA NTRS1991

Observations of the Earth in polarized light from the US Space Shuttle

During the four American Space Shuttle missions of year 1985, the crewmembers took pictures of the Earth in polarized light. Different problems were encountered in the quantitative use of the data: induced polarization by the shuttle window, lack of calibration correction of the window polarization and enveloped in flight calibration methods. The analysis of the selected data first confirmed the previous observation over snow and sand. A low polarization on these surfaces was observed. On the other hand, the measurements show the potentiability of the polarization for agricultural inventory. Contamination of the atmosphere is well characterized.

Roger, Jean-Claude↗
NASA NTRS1991

Measurement of the spectral signature of small carbon clusters at near and far infrared wavelengths

A significant percentage of the carbon inventory of the circumstellar and interstellar media may be in the form of large refractory molecules (or small grains) referred to as carbon clusters. At the small end, uneven numbers of carbon atoms seem to be preferred, whereas above 12 atoms, clusters containing an even number of carbon atoms appear to be preferred in laboratory chemistry. In the lab, the cluster C-60 appears to be a particularly stable form and has been nicknamed Bucky Balls because of its resemblance to a soccer ball and to geodesic domes designed by Buckminster Fuller. In order to investigate the prevalence of these clusters, and their relationship to the polycyclic aromatic hydrocarbons (PAHs) that have become the newest focus of IR astronomy, it is necessary to determine the spectroscopic characteristics of these clusters at near and far infrared wavelengths. Described here is the construction of a near to far IR laser magnetic resonance spectrometer that has been built at the University of California Berkeley in order to detect and characterize these spectra. The equipment produces carbon clusters by laser evaporation of a graphitic target. The clusters are then cooled in a supersonic expansion beam in order to simulate conditions in the interstellar medium (ISM). The expansion beam feeds into the spectrometer chamber and permits concentrations of clusters sufficiently high as to permit ultra-high resolution spectroscopy at near and far IR wavelengths. The first successful demonstration of this apparatus occurred last year when the laboratory studies permitted the observational detection of C-5 in the stellar outflow surrounding IRC+10216 in the near-IR. Current efforts focus on reducing the temperature of the supersonic expansion beam that transport the C clusters evaporated from a graphite target into the spectrometer down to temperatures as low as 1 K.

Tarter, J.↗
NASA NTRS1991

Terrestrial production vs. extraterrestrial delivery of prebiotic organics to the early Earth

A comprehensive treatment of comet/asteroid interaction with the atmosphere, ensuring surface impact, and resulting organic pyrolysis is required to determine whether more than a negligible fraction of the organics in incident comets and asteroids actually survived collision with Earth. Results of such an investigation, using a smoothed particle hydrodynamic simulation of cometary and asteroidal impacts into both oceans and rock, demonstrate that organics will not survive impacts at velocities approx. greater than 10 km s(exp -1), and that even comets and asteroids as small as 100m in radius cannot be aerobraked to below this velocity in 1 bar atmospheres. However, for plausible dense (10 bar CO2) early atmospheres, there will be sufficient aerobraking during atmospheric passage for some organics to survive the ensuing impact. Combining these results with analytical fits to the lunar impact record shows that 4.5 Gyr ago Earth was accreting at least approx. 10(exp 6) kg yr(exp 1) of intact cometary organics, a flux which thereafter declined with a approx. 100 Myr half-life. The extent to which this influx was augmented by asteroid impacts, as well as the effect of more careful modelling of a variety of conservative approximations, is currently being quantified. These results may be placed in context by comparison with in situ organic production from a variety of terrestrial energy sources, as well as organic delivery by interplanetary dust. Which source dominated the early terrestrial prebiotic inventory is found to depend on the nature of the early terrestrial atmosphere. However, there is an intriguing symmetry: it is exactly those dense CO2 atmospheres where in situ atmospheric production of organic molecules should be the most difficult, in which intact cometary organics would be delivered in large amounts.

Chyba, C. F.↗
NASA NTRS1991

Self assembly properties of primitive organic compounds

A central event in the origin of life was the self-assembly of amphiphilic, lipid-like compounds into closed microenvironments. If a primitive macromolecular replicating system could be encapsulated within a vesicular membrane, the components of the system would share the same microenvironment, and the result would be a step toward true cellular function. The goal of our research has been to determine what amphiphilic molecules might plausibly have been available on the early Earth to participate in the formation of such boundary structures. To this end, we have investigated primitive organic mixtures present in carbonaceous meteorites such as the Murchison meteorite, which contains 1-2 percent of its mass in the form of organic carbon compounds. It is likely that such compounds contributed to the inventory of organic carbon on the prebiotic earth, and were available to participate in chemical evolution leading to the emergence of the first cellular life forms. We found that Murchison components extracted into non-polar solvent systems are surface active, a clear indication of amphiphilic character. One acidic fraction self-assembles into vesicular membranes that provide permeability barriers to polar solutes. Other evidence indicates that the membranes are bimolecular layers similar to those formed by contemporary membrane lipids. We conclude that bilayer membrane formation by primitive amphiphiles on the early Earth is feasible. However, only a minor fraction of acidic amphiphiles assembles into bilayers, and the resulting membranes require narrowly defined conditions of pH and ionic composition to be stable. It seems unlikely, therefore, that meteoritic infall was a direct source of membrane amphiphiles. Instead, the hydrocarbon components and their derivatives more probably would provide an organic stock available for chemical evolution. Our current research is directed at possible reactions which would generate substantial quantities of membranogenic amphiphiles. One possibility is photochemical oxidation of hydrocarbons.

Deamer, D. W.↗
NASA NTRS1990

Turbomachinery

The discipline research in turbomachinery, which is directed toward building the tools needed to understand such a complex flow phenomenon, is based on the fact that flow in turbomachinery is fundamentally unsteady or time dependent. Success in building a reliable inventory of analytic and experimental tools will depend on how we treat time and time-averages, as well as how we treat space and space-averages. The challenge is to develop a set of computational and experimental tools which genuinely increase our understanding of the fluid flow and heat transfer in a turbomachine. Examples of the types of computational and experimental tools under current development, with progress to date, are examined. The examples include work in both the time-resolved and time-averaged domains.

Simoneau, Robert J.↗
NASA NTRS1992

Intelligent Processing Equipment Research and Development Programs of the Department of Commerce

The intelligence processing equipment (IPE) research and development (R&D) programs of the Department of Commerce are carried out within the National Institute of Standards and Technology (NIST). This institute has had work in support of industrial productivity as part of its mission since its founding in 1901. With the advent of factory automation these efforts have increasingly turned to R&D in IPE. The Manufacturing Engineering Laboratory (MEL) of NIST devotes a major fraction of its efforts to this end while other elements within the organization, notably the Material Science and Engineering Laboratory, have smaller but significant programs. An inventory of all such programs at NIST and a representative selection of projects that at least demonstrate the scope of the efforts are presented.

Simpson, J. A.↗
NASA NTRS1992

Papers Presented to the Workshop on the Evolution of the Martian Atmosphere

This volume contains papers that have been accepted for the Workshop on the Evolution of the Martian Atmosphere. The abstracts presented in the paper cover such topics as: modeling of the mars atmosphere from early development to present including specific conditions affecting development; studies of various atmospheric gases such as O2, SO2, CO2, NH3, and nitrogen; meteorite impacts and their effects on the atmosphere; and water inventories and cycles.

Source record↗
NASA NTRS1992

An ion mass spectrometer for measuring isotopic adundances and loss rates of O, C and H in Mars' upper atmosphere

The history of Mars' climate is clearly intimately linked to the evolution of its store of volatiles, particularly H2O, and CO2. The global CO2-H2O system is complex, with a number of production, loss, exchange, and buffering mechanisms operating between the atmosphere and the surface. For example, loss of these volatiles takes place through solar wind interaction with the upper atmosphere/ionosphere, ionospheric chemistry, and thermal escape. The atmospheric water inventory is, in turn, influenced by the exchange with polar water ice deposits and high latitude ground-ice. Atmospheric CO2, on the other hand, can be lost through adsorption in the regolith and in the formation of carbonates. Finally, oxygen is exchanged between atmospheric CO2 and H2O.

Elphic, R. C.↗
NASA NTRS1992

Marine Magnetic Data Holdings of World Data Center-a for Marine Geology and Geophysics

The World Data Center-A for Marine Geology and Geophysics is co-located with the Marine Geology & Geophysical Data Center, Boulder, CO. Fifteen million digital marine magnetic trackline measurements are managed within the GEOphysical DAta System (GEODAS). The bulk of these data were collected with proton precision magnetometers under Transit Satellite navigational control. Along-track sampling averages about 1 sample per kilometer, while spatial density, a function of ship's track and survey pattern, range from 4 to 0.02 data points/sq. km. In the near future, the entire geophysical data set will be available on CD-ROM. The Marine Geology and Geophysics Division (World Data Center-A for MGG), of the National Geophysical Data Center, handles a broad spectrum of marine geophysical data, including measurements of bathymetry, magnetics, gravity, seismic reflection subbottom profiles, and side-scan images acquired by ships throughout the world's oceans. Digital data encompass the first three, while the latter two are in analog form, recorded on 35mm microfilm. The marine geophysical digital trackline data are contained in the GEODAS data base which includes 11.6 million nautical miles of cruise trackline coverage contributed by more than 70 organizations worldwide. The inventory includes data from 3206 cruises with 33 million digital records and indexing to 5.3 million track miles of analog data on microfilm.

Sharman, George F.↗