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Nov 27, 2019
11/19
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Sterne, Jim, 1955-
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xvii, 331 pages : 24 cm
Topics: Internet (Réseau d'ordinateurs), Interplanetary dust, Computers Networks, World Wide Web,...
This volume is a compilation of papers presented at the Third Long Duration Exposure Facility (LDEF) Post-Retrieval Symposium. The papers represent the data analysis of the 57 experiments flown on the LDEF. The experiments include materials, coatings, thermal systems, power and propulsion, science (cosmic ray, interstellar gas, heavy ions, micrometeoroid, etc.), electronics, optics, and life science. In addition, papers on preliminary data analysis of EURECA, EOIM-3, and other spacecraft are...
Topics: NASA Technical Reports Server (NTRS), AEROSPACE ENVIRONMENTS, CONFERENCES, ENVIRONMENT SIMULATION,...
The primary objective of the research funded under this grant has been to perform a high angular resolution mapping survey of the far-infrared and submillimeter continuum emission from the dust cocoons surrounding young, deeply embedded massive stars and the ultracompact H II regions they create. The high infrared, submillimeter, and radio luminosity makes the ultracompact H II regions ideal tracers of current high-mass star formation. Detailed investigations of their structure, evolution, and...
Topics: NASA Technical Reports Server (NTRS), ANGULAR RESOLUTION, H II REGIONS, INFRARED ASTRONOMY,...
On June 24 through 26, 1996, a scientific conference entitled From Stardust to Planetesimals was held at the Westin Hotel, Santa Clara, California, as part of the 108th annual meeting of the Astronomical Society of the Pacific. Over the last decade, our understanding of the formation and early evolution of the solar system has advanced considerably due to progress that has been made simultaneously on many fronts. Stardust has been isolated in meteorites and interplanetary dust particles...
Topics: NASA Technical Reports Server (NTRS), INTERPLANETARY DUST, INTERSTELLAR MATTER, PLANETARY...
Three chemical groups of primary "silicate" spheres
Topics: NASA Technical Reports Server (NTRS), LEONID METEOROIDS, COMETS, INTERPLANETARY DUST, SILICATES,...
We report, for the first time, the identification of specific carbonaceous phases, present within iddingsite alteration zones of the Nakhla meteorite that possess discrete, well defined, structurally coherent morphologies. These structures bear superficial similarity to the carbonaceous nanoglobules [1] found in primitive chondrites interplanetary dust particles, although they are an order-of-magnitude larger in size. Introduction: It has been known for many years that some members of the...
Topics: NASA Technical Reports Server (NTRS), CARBONACEOUS MATERIALS, INTERPLANETARY DUST, GAS...
We show that a one-component variable-emissivity-spectral-index model (the free- model) provides more physically motivated estimates of dust temperature at the Galactic polar caps than one- or two-component fixed-emissivity-spectral-index models (fixed- models) for interstellar dust thermal emission at far-infrared and millimeter wavelengths. For the comparison we have fit all-sky one-component dust models with fixed or variable emissivity spectral index to a new and improved version of the...
Topics: NASA Technical Reports Server (NTRS), EMISSIVITY, INTERSTELLAR MATTER, MATHEMATICAL MODELS, TIME...
The Triple F (Fresh From the Fridge) mission, a Comet Nucleus Sample Return, has been proposed to ESA's Cosmic Vision program. A sample return from a comet enables us to reach the ultimate goal of cometary research. Since comets are the least processed bodies in the solar system, the proposal goes far beyond cometary science topics (like the explanation of cometary activity) and delivers invaluable information about the formation of the solar system and the interstellar molecular cloud from...
Topics: NASA Technical Reports Server (NTRS), COMET NUCLEI, SAMPLE RETURN MISSIONS, SOLAR SYSTEM EVOLUTION,...
The electronic sensors of the Interplanetary Dust Experiment (IDE) recorded precise impact times and approximate directions for submicron to approximately 100 micron size particles on all six primary sides of the spacecraft for the first 346 days of the LDEF orbital mission. Previously-reported analyses of the timed impact data have established their spatio-temporal features, including the demonstration that a preponderance of the particles in this regime are orbital debris and that a large...
Topics: NASA Technical Reports Server (NTRS), INTERPLANETARY DUST, LEADING EDGES, LONG DURATION EXPOSURE...
Analysis of the data from the Long Duration Exposure Facility (LDEF) Interplanetary Dust Experiment (IDE) sun sensors has allowed a confirmation of the attitude of LDEF during its first year in orbit. Eight observations of the yaw angle at specific times were made and are tabulated in this paper. These values range from 4.3 to 12.4 deg with maximum uncertainty of plus or minus 2.0 deg and an average of 7.9 deg. No specific measurements of pitch or roll were made but the data indicates that LDEF...
Topics: NASA Technical Reports Server (NTRS), ATTITUDE (INCLINATION), INTERPLANETARY DUST, LONG DURATION...
Many meteorites and interplanetary dust particles (IDP's) with primitive compositions contain significant amounts of phyllosilicates, which are generally interpreted as evidence of protoplanetary aqueous alteration at an early period in the solar system. These meteorites are chondrites of the carbonaceous and ordinary varieties. Characterization of phyllosilicates in these materials is important because of the important physico-chemical information they hold, e.g., from well characterized...
Topics: NASA Technical Reports Server (NTRS), CHLORINE COMPOUNDS, CHONDRITES, CLAYS, INTERPLANETARY DUST,...
The LDEF contained 57 individual experiment trays or tray portions specifically designed to characterize critical aspects of meteoroid and debris environment in low-Earth orbit (LEO). However, it was realized from the beginning that the most efficient use of the satellite would be to characterize impact features from the entire surface of the LDEF. With this in mind particular interest has focused on common materials facing in all 26 LDEF facing directions; among the most important of these...
Topics: NASA Technical Reports Server (NTRS), EARTH ORBITAL ENVIRONMENTS, ELECTRON MICROSCOPY, IMPACT...
The primary benefit of accurately quantifying and characterizing the space environmental effects on materials is longer instrument and spacecraft life. Knowledge of the limits of materials allows the designer to optimize the spacecraft design so that the required life is achieved. Materials such as radiator coatings that have excellent durability result in the design of smaller radiators than a radiator coated with a lower durability coating. This may reduce the weight of the spacecraft due to...
Topics: NASA Technical Reports Server (NTRS), AEROSPACE ENVIRONMENTS, ENVIRONMENT EFFECTS, EURECA (ESA),...
The Interplanetary Dust Experiment (IDE) provided high time resolution detection of microparticle impacts on the Long Duration Exposure Facility satellite. Particles, in the diameter range from 0.2 microns to several hundred microns, were detected impacting on six orthogonal surfaces of the gravity-gradient stabilized LDEF spacecraft. The total sensitive surface area was about one square meter, distributed between LDEF rows 3 (Wake or West), 6 (South), 9 (Ram or East), 12 (North), as well as...
Topics: NASA Technical Reports Server (NTRS), EARTH ORBITAL ENVIRONMENTS, IMPACT DAMAGE, INTERPLANETARY...
During the first 346 days of the LDEF's almost 6 year stay in space, the metal oxide silicon detectors of the Interplanetary Dust Experiment (IDE) recorded over 15,000 impacts, most of which were separated in time by integer multiples of the LDEF orbital period (called multiple orbit event sequences, or MOES). Simple celestial mechanics provides ample reason to expect that a good deal of information about the orbits of the impacting debris particles can be extracted from these MOES, and so a...
Topics: NASA Technical Reports Server (NTRS), EARTH ORBITAL ENVIRONMENTS, INTERPLANETARY DUST, LONG...
This report presents the results of research undertaken to study various problems associated with hypervelocity capture of dust particles in aerogel. The primary topics investigated were the properties of shocked aerogel and the requirements for reliable capture of particles on the STARDUST mission. In particular, the viscosity of shocked aerogel has been an open question. The results presented here suggest that the viscosity of aerogel at high impact velocities is negligible, although there...
Topics: NASA Technical Reports Server (NTRS), COSMIC DUST, DUST COLLECTORS, INTERPLANETARY DUST,...
The Long Duration Exposure Facility (LDEF) materials were useful for testing technical concepts that needed to be validated for the Cosmic Dust Collector Facility (CDCF) - a large instrument that was under study for inclusion on the upcoming Space Station. As it turned out, CDCF, which was approved at one point as an external payload, was ultimately canceled due to the scaling back of the Space Station capabilities. However, the study of cosmic dust is still a field of great interest for NASA,...
Topics: NASA Technical Reports Server (NTRS), COSMIC DUST, DUST COLLECTORS, FOILS (MATERIALS),...
In January 2006, the STARDUST mission successfully returned dust samples from the tail of comet 81P/Wild 2 in two principal collection media, low density silica aerogel and Al foil. While hypervelocity impacts at 6.1 km/s, the encounter velocity of STARDUST, into Al foils are generally highly disruptive for natural, silicate-dominated impactors, previous studies have shown that many craters retain sufficient residue to allow a determination of the elemental and isotopic compositions of the...
Topics: NASA Technical Reports Server (NTRS), INTERPLANETARY DUST, CHEMICAL COMPOSITION, STARDUST MISSION,...
In order to describe the total mineralogical diversity within primitive extraterrestrial materials, individual interplanetary dust particles (IDPs) collected from the stratosphere as part of the JSC Cosmic Dust Curatorial Program were analyzed using a variety of AEM techniques. Identification of over 250 individual grains within one chondritic porous (CP) IDP shows that most phases could be formed by low temperature processes and that heating of the IDP during atmospheric entry is minimal and...
Topics: NASA Technical Reports Server (NTRS), CARBONACEOUS CHONDRITES, CHEMICAL COMPOSITION, INTERPLANETARY...
In an effort to classify and determine the origin of interplanetary dust particles (IDPs), 14 of these particles were studied using a laser microprobe/mass spectrometer. The mass spectra for these particles varied dramatically. Some particles released hydroxide or water which probably originated in hydroxide-bearing minerals or hydrates. Others produced spectra which included a number of hydrocarbons and resembled meteorite spectra. However, none of the individual IDPs gave spectra which could...
Topics: NASA Technical Reports Server (NTRS), CARBONACEOUS CHONDRITES, INTERPLANETARY DUST, MASS SPECTRA,...
Since 1981, NASA has routinely collected interplanetary dust particles (IDPs) in the stratosphere by inertial impact onto silicone oil-coated flat plate collectors deployed on the wings of high-altitude aircraft [1]. The highly viscous oil traps and localizes the particles, which can fragment during collection. Particles are removed from the collectors with a micromanipulator and washed of the oil using organic solvents, typically hexane or xylene. While silicone oil is an efficient collection...
Topics: NASA Technical Reports Server (NTRS), COSMIC DUST, STRATOSPHERE, COLLECTION, INTERPLANETARY DUST,...
In the outer envelopes of red giants, when the gas cools sufficiently, molecules and solids form. Thermodynamically, the most stable molecule is CO, and it is usually assumed that all the available carbon and oxygen are consumed in the formation of this molecule (Salpeter 1977). If the carbon abundance is greater than the oxygen abundance, then the carbon left over after the formation of CO is available for solid grains. Because carbon is by far the most abundant species available for making...
Topics: NASA Technical Reports Server (NTRS), ASTRONOMY, ASTROPHYSICS, CARBON, INTERPLANETARY DUST, RED...
Cursory examination of the Long Duration Exposure Facility (LDEF) shows the existence of thousands of impact craters of which less than 1/3 exceed 0.3 mm in diameter; the largest crater is 5.5 mm. Few craters show oblique impact morphology and, surprisingly, only a low number of craters have recognizable impact debris. Study of this debris could be of interest to exobiology in terms of C content and carbonaceous materials. All craters greater that 0.3 mm have been imaged and recorded into a...
Topics: NASA Technical Reports Server (NTRS), CHEMICAL BONDS, EXOBIOLOGY, HYPERVELOCITY GUNS, HYPERVELOCITY...
The research supported by the NASA ADP contract NAG5-1153 has been completed. The attached paper, which will be submitted for publication in the Astrophysical Journal in January 1992, presents the results of this work. Here is a summary of the project and its results. A set of computer programs was developed to process the raw 60 micron and 100 micron IRAS survey data. The programs were designed to detect faint extended emission surrounding a bright unresolved source. Candidate objects were...
Topics: NASA Technical Reports Server (NTRS), A STARS, ASTROPHYSICS, CARBON STARS, INFRARED ASTRONOMY...
A meteor radar system has been operated on a routine basis near Christchurch, New Zealand, to determine the orbits of Earth-impacting interplanetary dust and meteoroids. The system sensitivity is +13 visual magnitude, corresponding to approximately 100 micron sized meteoroids. With an orbital precision of 2 degrees in angular elements and 10 percent in orbital energy (1/a), the operation yields an average of 1500 orbits daily with a total to date in excess of 10(exp 5). The use of pc's and...
Topics: NASA Technical Reports Server (NTRS), ASTEROIDS, DATA REDUCTION, INTERPLANETARY DUST, METEOROIDS,...
During KOSI (comet simulation) experiments, mineral-ice mixtures are observed in simulated space conditions. Emission of ice-/dust particles from the sample surface is observed by means of different devices. The particle trajectories are recorded with a video system. In the following analysis we extracted the parameters: particle count rate, spatial distribution of starting points on the sample surface, and elevation angle and particle velocity at distances up to 5 cm from the sample surface....
Topics: NASA Technical Reports Server (NTRS), COMETS, COMPUTERIZED SIMULATION, ELEVATION ANGLE,...
An inward precipitator collects particles initially dispersed in a gas throughout either a cylindrical or spherical chamber onto a small central planchet. The instrument is effective for particle diameters greater than about 1 micron. One use is the collection of interplanetary dust particles (IDPs) which are stopped in a noble gas (xenon) by drag and ablation after perforating the wall of a thin-walled spacecraft-mounted chamber. First, the particles are positively charged for several seconds...
Topics: NASA Technical Reports Server (NTRS), CORONAS, CYLINDRICAL CHAMBERS, ELECTRIC FIELDS, ELECTROSTATIC...
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Apr 13, 2018
04/18
by
Funk, Tom, 1965-
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Includes bibliographical references (pages 159-165) and index
Topics: Electronic commerce, Web 2.0, Internet marketing, Information technology, Electronic commerce,...
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377
May 23, 2011
05/11
by
Mazely, Troy L.; Friedl, Randall R.; Sander, Stanley P
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Peroxyacetyl nitrate (PAN) vapor was photolyzed at 248 nm, and the NO2 photoproduct was detected by laser-induced fluorescence. The quantum yield for the production of NO2 from PAN photolysis was determined by comparison to HNO3 photolysis data taken under identical experimental conditions. The average of data collected over a range of total pressures, precursor concentrations, and buffer gases was 0.83 /- 0.09 for the NO2 quantum yield, where the statistical uncertainty is 2 standard...
Topics: INTERPLANETARY DUST, PARTICLE SIZE DISTRIBUTION, GRAIN SIZE, PARTICLE MOTION, PARTICLE COLLISIONS,...
This proposal supported observations of comets at submillimeter wavelengths. The prime science objectives were to use rotational transitions in molecules to measure the compositions and outgassing rates of the comets. The second science objectives focussed on the use of the submillimeter continuum radiation to provide a measure of the solid particle content and production rate in the comets. Both quantities provide fundamental constraints on the nature of these primitive bodies. The gas and...
Topics: NASA Technical Reports Server (NTRS), COMETS, SUBMILLIMETER WAVES, SPACE OBSERVATIONS (FROM EARTH),...
Ground based images obtained hourly by seven observatories are used to study Martian phenomena. Maps of global dust storms show the degree of activity of the storm depends both on the region and on the time of day. Statistical analysis of regional contrast variations on the images supports the opinion that the contrasts in the brightness of the light and dark areas depends on the Martian season. Residual differences may be due to a phase angle dependence. Diagrams confirm the earlier finding...
Topics: NASA Technical Reports Server (NTRS), ANNUAL VARIATIONS, INTERPLANETARY DUST, MARS ATMOSPHERE,...
This grant funded measurements of extraterrestrial He-3 in particles extracted from polar ice samples. The overall objective was to develop measurements of He-3 as tracers of the flux of interplanetary dust particles (IDP's) to the earth. To our knowledge these are the first such measurements, apart from our earlier work. The project also funded an EPO activity - a climate and global change workshop for high school science teachers.
Topics: NASA Technical Reports Server (NTRS), HELIUM ISOTOPES, INTERPLANETARY DUST, POLAR REGIONS, ICE,...
Analytical tools are presented in two reports. The first is a probability analysis of the orbital distribution of events in relation to dust flux density observed in Pioneer 8 and 9 distributions. A distinction is drawn between asymmetries caused by random fluctuations and systematic variations, by calculating the probability of any particular asymmetry. The second article discusses particle trajectories for a repulsive force field. The force on a particle due to solar radiation pressure is...
Topics: NASA Technical Reports Server (NTRS), EQUATIONS OF MOTION, FUNCTIONS (MATHEMATICS), PARTICLE...
Morphological analyses of micrometeorite craters found on lunar rocks and laboratory simulation experiments are used to formulate a meteoritic interplanetary dust particle for optical scattering calculations that is roughly spherical and has a density of 2g cm/3. The model particle has chondritic elemental abundances and also contains a high content of finely dispersed carbon.
Topics: NASA Technical Reports Server (NTRS), INTERPLANETARY DUST, METEOROID DUST CLOUDS, PARTICLES,...
The Sutter's Mill meteorite fell in northern California on April 22, 2012, and numerous pieces have been recovered and studied with several analytical techniques [1]. We present a Fourier-transform infrared (FTIR) spectroscopy analysis of fragments from several stones of the meteorite. Methods and analysis: Infrared spectra of samples SM2 and SM12 were recorded with a Nicolet iN10 MX FTIR microscope in the mid-IR range (4000-650/cm; spectral resolution 4/cm), while samples SM20 and SM30 were...
Topics: NASA Technical Reports Server (NTRS), METEORITES, INFRARED SPECTROSCOPY, INTERPLANETARY DUST,...
Chondritic porous interplanetary dust particles (CP-IDPs) have been linked to comets by their fragile structure, primitive mineralogy, dynamics, and abundant interstellar materials. But differences have emerged between 'cometary' CP-IDPs and comet 81P/Wild 2 Stardust Mission samples. Particles resembling Ca-Al-rich inclusions (CAIs), chondrules, and amoeboid olivine aggregates (AOAs) in Wild 2 samples are rare in CP-IDPs. Unlike IDPs, presolar materials are scarce in Wild 2 samples. These...
Topics: NASA Technical Reports Server (NTRS), SOLAR NEBULA, INTERPLANETARY DUST, INTERSTELLAR CHEMISTRY,...
A new hybrid technique of visual and video meteor observations was developed to provide high precision near real-time flux measurements for satellite operators from airborne platforms. A total of 33,000 Leonids. recorded on video during the 1999 Leonid storm, were watched by a team of visual observers using a video head display and an automatic counting tool. The counts reveal that the activity profile of the Leonid storm is a Lorentz profile. By assuming a radial profile for the dust trail...
Topics: NASA Technical Reports Server (NTRS), COUNTING, ENCOUNTERS, LEONID METEOROIDS, VISUAL OBSERVATION,...
Interplanetary dust pervades the inner Solar System, giving rise to a prominent glow above the horizon at sunrise and sunset known as the zodiacal light. This dust derives from the disintegration of comets as they approach the Sun and from collisions among main-belt asteroids. The Earth accretes roughly 4x10(exp 6) kg/year of 1 - 1,000 micron dust particles as they spiral into the Sun under the influence of Poynting-Robertson drag and solar wind drag. Samples of these grains have been collected...
Topics: NASA Technical Reports Server (NTRS), INTERPLANETARY DUST, MINERALOGY, COMPOSITION (PROPERTY),...
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102
Jul 21, 2010
07/10
by
Moseley, H.; Silverberg, R. F
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Some carbon-rich planetary nebulae exhibit a strong broad emission feature beginning at Lambda which is approximately 24 microns and extending to Lambda greater than 30 microns. Thirty to 55 micron spectrophotometry of Ic 418 and NGC 6572, both of which have the strong broad emission feature, allow the wavelength dependence of the emissivity of the dust responsible for the feature to be defined. Comparison with laboratory spectra of candidate materials which are likely to condense in a...
Topics: INTERPLANETARY DUST, POYNTING-ROBERTSON EFFECT, RADIATION PRESSURE, SPATIAL DISTRIBUTION,...
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299
Jun 12, 2011
06/11
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Weaver Smith, Suzanne; Song, Haiping; Baker, John R.; Black, Jonathan; Muheim, Danniella M
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Solar sails employ a unique form of propulsion, gaining momentum from incident and reflected photons. However, the momentum transferred by an individual photon is extremely small. Consequently, a solar sail must have an extremely large surface area and also be extremely light. The flexibility of the sail then must be considered when designing or evaluating control laws. In this paper, solar sail flexibility and its influence on control effectiveness is considered using idealized two-dimensional...
Topics: MARS MISSIONS, SHORT CIRCUITS, SPACE SUITS, LASER DOPPLER VELOCIMETERS, SCIENCE, RESEARCH AND...
Chondritic porous interplanetary dust particles (CP-IDPs) may be the best preserved remnants of primordial solar system materials, in part because they were not affected by parent body hydrothermal alteration. Their primitive characteristics include fine grained, unequilibrated, anhydrous mineralogy, enrichment in volatile elements, and abundant molecular cloud material and silicate stardust. However, while the majority of CP-IDP materials likely derived from the Solar System, their formation...
Topics: NASA Technical Reports Server (NTRS), CHONDRITES, INTERPLANETARY DUST, STARDUST MISSION,...
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Jul 21, 2010
07/10
by
Hanner, M. S
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Physical property data of cometary grains are derived primarily from thermal emission measurement and optical scattering. Results consistent with the properties of micrometeorites collected in the stratosphere are described.
Topics: CHEMICAL PROPERTIES, INTERPLANETARY DUST, MORPHOLOGY, STRATOSPHERE, AUGER SPECTROSCOPY, ELECTRON...
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353
May 30, 2011
05/11
by
Wen, Fang; Willett, Peter; Deb, Somnat
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In this paper the classical ''Westland'' set of empirical accelerometer helicopter data is analyzed with the aim of condition monitoring for diagnostic purposes. The goal is to determine features for failure events from these data, via a proprietary signal processing toolbox, and to weigh these according to a variety of classification algorithms. As regards signal processing, it appears that the autoregressive (AR) coefficients from a simple linear model encapsulate a great deal of information...
Topics: ANOMALIES, LOW TEMPERATURE, METEORITES, MOLECULAR INTERACTIONS, PHOTODISSOCIATION, PHOTOLYSIS,...
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Aug 2, 2010
08/10
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Scattergood, T. W.; Mckay, C. P.; Borucki, W. J.; Giver, L. P.; Vanghyseghem, H.; Parris, J. E.; Miller, S. L
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In order to study the production of organic compounds in plasmas (and shocks), various mixtures of N2, CH4, and H2, modeling the atmosphere of Titan, were exposed to discrete sparks, laser-induced plasmas (LIP) and ultraviolet light. The yields of HCN and simple hydrocarbons were measured and compared to those calculated from a simple quenched thermodynamic equilibrium model. The agreement between experiment and theory was fair for HCN and C2H2. However, the yields of C2H6 and other...
Topics: AEROGELS, FREON, IDENTIFYING, LOW DENSITY MATERIALS, LOW EARTH ORBITS, OILS, RESIDUES, SOLVENTS,...
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159
Jul 21, 2010
07/10
by
Stencel, R. E
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A multistep scenario which describes a plausible mass loss mechanism associated with red giant and related stars is outlined. The process involves triggering a condensation instability in an extended chromosphere, leading to the formation of cool, dense clouds which are conducive to the formation of molecules and dust grains. Once formed, the dust can be driven away from the star by radiation pressure. Consistency with various observed phenomena is discussed.
Topics: CARBON, POLYMERIZATION, TRANSMISSION ELECTRON MICROSCOPY, CRYSTALLIZATION, GRAIN SIZE,...
Interplanetary dust particles (IDPs) interact with all planetary atmospheres and leave their imprint as perturbations of the background atmospheric chemistry and structure. They lead to layers of metal ions that can become the dominant positively charged species in lower ionospheric regions. Theoretical models and radio occultation measurements provide compelling evidence that such layers exist in all planetary atmospheres. In addition IDP ablation products can affect neutral atmospheric...
Topics: NASA Technical Reports Server (NTRS), INTERPLANETARY DUST, PLANETARY ATMOSPHERES, METAL IONS,...
The study of formation and destruction processes of cosmic dust is essential to understand and to quantify the budget of extraterrestrial organic molecules. Although dust with all its components plays an important role in the evolution of interstellar chemistry and in the formation of organic molecules, little is known on the formation and destruction processes of carbonaceous dust. PAHs are important chemical building blocks of interstellar dust. They are detected in interplanetary dust...
Topics: NASA Technical Reports Server (NTRS), POLYCYCLIC AROMATIC HYDROCARBONS, COSMIC DUST, CARBON, GRAIN...
639
639
Sep 20, 2010
09/10
by
Russell, Steven G
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A new Rayleigh-Ritz stress analysis methodology that was developed for composite panels containing cutouts is described. The procedure, which makes use of a general assumed displacement field, accommodates circular and elliptical cutouts in biaxially loaded rectangular composite panels. Symmetric integral padups around the cutout can be included in the analysis. Benchmark results are presented to demonstrate the accuracy of the technique. Strength predictions based on the average stress...
Topics: HYPERVELOCITY IMPACT, TRAILING EDGES, ALUMINUM, FLAKES, GOLD, IMPACTORS, INTERPLANETARY DUST,...
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205
Jun 1, 2011
06/11
by
Alcorn, George; Corbo, Jim; Martin, Deborah; Levin, Lenn
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User servicing for Space Station Freedom (SSF) will span an evolutionary period paralleling that of the station's growth plan. This will include a baseline servicing configuration followed by a final growth phase in which all user servicing requirements are satisfied. Although the basic requirements for user servicing are not station configuration dependent, the emphasis placed on different aspects of servicing may change with the eventual SSF growth objectives. This paper will discuss the...
Topics: EXTRATERRESTRIAL MATTER, HELIUM ISOTOPES, OSMIUM ISOTOPES, PLATINUM, PROJECTILES, SEDIMENTS,...
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124
Jul 21, 2010
07/10
by
Rietmeijer, F. J. M
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The nature of hydrocarbons and properties of elemental carbon in circumstellar, interstellar, and interplanetary dust is a long standing problem in astronomy and meteorite research. The textures and crystallographical properties of poorly graphitized carbon (PGC) from carbonaceous chondrites and Chondritic Porous Aggregates (CPAs) are comparable with PGCs formed by dehydrogenation and carbonization of hydrocarbon precursors under natural terrestrial and experimental conditions. A multistage...
Topics: ANOMALIES, FRACTIONATION, METEORITES, NUCLEAR FUSION, PLANETS, TEMPERATURE EFFECTS, INTERPLANETARY...
