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Hamilton Sundstrand (HS), together with NASA Johnson Space Center, developed methods to metallurgically join graphite fiber to aluminum. The goal of the effort was to demonstrate improved thermal conductance, tensile strength and manufacturability compared to existing epoxy bonded techniques. These improvements have the potential to increase the performance and robustness of phase change material heat sinks that use graphite fibers as an interstitial material. Initial work focused on evaluating...
Topics: NASA Technical Reports Server (NTRS), BRAZING, CARBON FIBERS, GRAPHITE, HEAT SINKS, METALLIZING,...
Numerical simulations have been completed for a variety of designs for a 90 deg elbow duct. The objective is to identify a design that minimizes the dynamic load entering a LOX turbopump located at the elbow exit. Designs simulated to date indicate that simpler duct geometries result in lower losses. Benchmark simulations have verified that the compressible flow code used in this study is applicable to these incompressible flow simulations.
Topics: NASA Technical Reports Server (NTRS), COMPUTATIONAL FLUID DYNAMICS, LIQUID OXYGEN, TURBINE PUMPS,...
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This article investigates the role of a free jet on the sound radiated from a jet. In particular, the role of an infinite wind tunnel, which simulates the forward flight condition, is compared to that of a finite wind tunnel. The second configuration is usually used in experiments, where the microphones are located in a static ambient medium far outside the free jet. To study the effect of the free jet on noise, both propagation and source strength need to be addressed. In this work, the exact...
Topics: NASA Technical Reports Server (NTRS), AEROACOUSTICS, FREE JETS, GREEN'S FUNCTIONS, PARALLEL FLOW,...
This document provides the capabilities of the Wide Field and Planetary Camera 2 Instrument.
Topics: NASA Technical Reports Server (NTRS), CAMERAS, HANDBOOKS, HUBBLE SPACE TELESCOPE,...
The progress made during the period 1 Jan. - 30 Jun. 1993 on the numerical study of the effects of icing on viscous flow over wings is summarized. The tasks performed were development of 3-D boundary layer methods for accurate estimates of the velocity field and surface heat transfer rates in the vicinity of the leading edge ice shape; studies of the effects of icing on 3-D highlift system performance; and continued improvement and validation of the 3-D Navier-Stokes solver. Results are...
Topics: NASA Technical Reports Server (NTRS), BOUNDARY LAYER FLOW, ICE FORMATION, LEADING EDGES, THREE...
Topic: NASA Technical Reports Server (NTRS)
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The objective of this investigation is the experimental evaluation of the influence of inlet turbulence intensity on secondary flow development in a turning duct. The existing 25.4 cm square turning duct (90) facility is being utilized to investigate of bulk turbulence levels on secondary flow development. The large scale duct flow facility allows detailed mean velocity and turbulence quantities to be measured at several streamwise planes in the curved duct. Non-intrusive laser velocimetry is...
Topics: NASA Technical Reports Server (NTRS), BOUNDARY LAYERS, DUCTED FLOW, FLOW DISTRIBUTION, SECONDARY...
Topic: NASA Technical Reports Server (NTRS)
Hybrid computerized simulation for backup entry ranging schemes evaluation for earth orbital missions
Topic: NASA Technical Reports Server (NTRS)
It is proposed to carry out slitless spectroscopy at ultraviolet wavelengths from orbit of meteoric debris associated with comets. The Eta Aquarid, Orionid/Halley, and the Persied/1962 862 Swift-Tuttle showers would be principal targets. Low light level, ultraviolet video technique will be used during night side of the orbit in a wide field, earthward viewing mode. Data will be stored in compact video cassette recorders. The experiment may be configured as a GAS package or in the HITCHHIKER...
Topics: NASA Technical Reports Server (NTRS), COMETS, DEBRIS, METEORITES, SPACE SHUTTLE PAYLOADS,...
Adhesion studies of iron surfaces with adsorbed hydrocarbons
Topic: NASA Technical Reports Server (NTRS)
There are no author-identified significant results in this report.
Topics: NASA Technical Reports Server (NTRS), INFESTATION, INSECTS, PLANTS (BOTANY), TEXAS, CROPS, EREP,...
Topic: NASA Technical Reports Server (NTRS)
This is a theoretical research project aimed at: (1) development, testing, and refining of inverse methods for determining regional and global transient source and sink strengths for long lived gases important in ozone depletion and climate forcing, (2) utilization of inverse methods to determine these source/sink strengths which use the NCAR/Boulder CCM2-T42 3-D model and a global 3-D Model for Atmospheric Transport and Chemistry (MATCH) which is based on analyzed observed wind fields...
Topics: NASA Technical Reports Server (NTRS), DATA MANAGEMENT, GASES, NUMERICAL ANALYSIS, TECHNOLOGIES,...
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by NASA Technical Reports Server (NTRS)
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The flux of meteoroids, or number of meteoroids per unit area per unit time, is critical for calibrating models of meteoroid stream formation and for estimating the hazard to spacecraft from shower and sporadic meteors. Although observations of meteors in the millimetre to centimetre size range are common, flux measurements (particularly for sporadic meteors, which make up the majority of meteoroid flux) are less so. It is necessary to know the collecting area and collection time for a given...
Topics: NASA Technical Reports Server (NTRS), METEOROID CONCENTRATION, METEOROIDS, METEORITES, MILLIMETER...
Automated Rendezvous and Capture requires the determination of the 6 DOF relating two free bodies. Sensor systems that can provide such information have varying sizes, weights, power requirements, complexities, and accuracies. One type of sensor system that can provide several key advantages is a binocular stereo vision system.
Topics: NASA Technical Reports Server (NTRS), BINOCULAR VISION, CAMERAS, DIGITAL SYSTEMS, SPACE RENDEZVOUS,...
A description of the Hamburg tank and carriage is provided as well as a layout of the control station and generator room.
Topic: NASA Technical Reports Server (NTRS)
The possibility of applying the most recent conservative and widely applied numerical techniques in gas dynamics to problems encountered in meteorological computations is investigated. Solutions of the advection equation are obtained using conservative differencing methods. These results are compared to those obtained by differencing the advection equation directly. The comparison shows that better results are obtained when the conservative form of governing equation is used. In addition,...
Topics: NASA Technical Reports Server (NTRS), ADVECTION, ATMOSPHERIC MODELS, CONSERVATION EQUATIONS, FINITE...
This paper addresses the effects of a cutout on the buckling and postbuckling behavior of rectangular plates made of advanced composite materials. An overview of past research is presented, and several key findings and behavioral characteristics are discussed. These findings include the effects of cutout size, shape, eccentricity, and orientation; plate aspect and slenderness ratios; loading and boundary conditions; and plate orthotropy and anisotropy. Some overall important findings of these...
Topics: NASA Technical Reports Server (NTRS), RECTANGULAR PLATES, BUCKLING, LAMINATES, ASPECT RATIO,...
A quartz hollow tube cathode was used to determine the operating conditions within a mercury orificed hollow cathode. Insert temperature profiles, cathode current distributions, plasma properties profile, and internal pressure-mass flow rate results are summarized and used in a phenomenological model which qualitatively describes electron emission and plasma production processes taking place within the cathode. By defining an idealized ion production region within which most of the plasma...
Topics: NASA Technical Reports Server (NTRS), ELECTRON EMISSION, HOLLOW CATHODES, ION PROPULSION,...
To obtain optimum sensitivity a submillimeter space observatory will require low temperature mirrors (approx. 3K) and very low temperature detectors (< or approx. 0.1 K). Both of these temperatures have been achieved by space cryogenic systems, but neither for a 10 year duration. Past systems used superfluid helium to provide direct cooling in the 1 to 2 K range (IRAS, COBE, IRTS, ISO) or as an upper stage for an adiabatic demagnetization refrigerator to achieve temperatures down to 0.06...
Topics: NASA Technical Reports Server (NTRS), CRYOGENIC EQUIPMENT, CRYOGENIC COOLING, ASTRONOMICAL...
The performance of the University of California at San Diego (UCSD) Table Mountain telescope was evaluated to determine the potential of such an instrument for optical angular tracking. This telescope uses a Ronchi ruling to measure differential positions of stars at the meridian. The Ronchi technique is summarized and the operational features of the Table Mountain instrument are described. Results from an analytic model, simulations, and actual data are presented that characterize the...
Topics: NASA Technical Reports Server (NTRS), DEEP SPACE NETWORK, INSTRUMENT ERRORS, MATHEMATICAL MODELS,...
Topic: NASA Technical Reports Server (NTRS)
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A solid state device including glass containing SiO.sub.2, consisting essentially of the composition, in percent by weight, in the range of: SiO.sub.2 95-99.5 and Al 0.5 to 5.0.
Topics: NASA Technical Reports Server (NTRS), ELASTIC PROPERTIES, GLASS, SOLID STATE DEVICES, PATENTS,...
Report presents the results of an investigation to determine the equilibrium temperature and heat-transfer coefficients for transverse cylinders in a high-speed stream of rarefied gas measured over a range of Knudsen numbers (ratio of molecular-mean-free path to cylinder diameter) from 0.025 to 11.8 and for Mach numbers from 2.0 to 3.3. The range of free-stream Reynolds numbers was from 0.28 to 203. The models tested were 0.0010-, 0.0050-, 0.030-, 0.051-, 0.080-, and 0.126-inch -diameter...
Topic: NASA Technical Reports Server (NTRS)
Some recent developments on integrated damping mechanics for unidirectional composites, laminates, and composite structures are reviewed. Simplified damping micromechanics relate the damping of on-axis and off-axis composites to constituent properties, fiber volume ratio, fiber orientation, temperature, and moisture. Laminate and structural damping mechanics for thin composites are summarized. Discrete layer damping mechanics for thick laminates, including the effects of interlaminar shear...
Topics: NASA Technical Reports Server (NTRS), COMPOSITE STRUCTURES, LAMINATES, MICROMECHANICS, POLYMER...
The Autonomous Landing and Hazard Avoidance Technology (ALHAT) Project was chartered to develop and mature to a Technology Readiness Level (TRL) of six an autonomous system combining guidance, navigation and control with real-time terrain sensing and recognition functions for crewed, cargo, and robotic planetary landing vehicles. The ALHAT System must be capable of identifying and avoiding surface hazards to enable a safe and accurate landing to within tens of meters of designated and certified...
Topics: NASA Technical Reports Server (NTRS), HELICOPTERS, FLIGHT TESTS, AUTONOMOUS NAVIGATION, AVIONICS,...
The purpose is to provide a research tool, a receiver, such that engineers interested in examining Loran-C performance, usefulness, and other properties will have a flexible, modifiable, and well-known piece of receiving hardware. The significant improvements to the Loran-C receiver are summarized.
Topics: NASA Technical Reports Server (NTRS), AIR TRANSPORTATION, EQUIPMENT SPECIFICATIONS, LORAN C,...
No abstract available
Topic: NASA Technical Reports Server (NTRS)
This viewgraph presentation describes a test simulate the transient effects of cosmic ray impacts on near infrared focal plane arrays. The objectives of the test are to: 1) Characterize proton single events as function of energy and angle of incidence; 2) Measure charge spread (crosstalk) to adjacent pixels; 3) Assess transient recovery time.
Topics: NASA Technical Reports Server (NTRS), NEAR INFRARED RADIATION, FOCAL PLANE DEVICES, RADIATION...
Orbital solar power plants, which beam power to earth by microwave, are compared with ground-based solar and conventional baseload power plants. Candidate systems were identified for three types of plants and the selected plant designs were then compared on the basis of economic and social costs. The representative types of plant selected for the comparison are: light water nuclear reactor; turbines using low BTU gas from coal; central receiver with steam turbo-electric conversion and thermal...
Topics: NASA Technical Reports Server (NTRS), LIGHT WATER BREEDER REACTORS, PHOTOVOLTAIC CELLS, SOLAR...
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The program goals were determined after consideration of the weaknesses in our understanding of atmospheric effects on sonic boom waveforms left in the wake of the cancellation of the U.S. SST in the 70's and the advancements in acoustics and atmospheric science since that time. For example, a considerable body of knowledge on molecular absorption has built up in the acoustics community over the last 15 years and this has not been incorporated into the sonic boom theory. Further, it was felt...
Topics: NASA Technical Reports Server (NTRS), ACOUSTIC PROPERTIES, ATMOSPHERIC ATTENUATION, ATMOSPHERIC...
The U.S. government technical report is a primary means by which the results of federally funded research and development (R&D) are transferred to the U.S. aerospace industry. However, little is known about this information product in terms of its actual use, importance, and value in the transfer of federally funded R&D. To help establish a body of knowledge, the U.S. government technical report is being investigated as part of the NASA/DOD Aerospace Knowledge Diffusion Research...
Topics: NASA Technical Reports Server (NTRS), AEROSPACE ENGINEERING, AEROSPACE INDUSTRY, INFORMATION...
This paper presents the correctness proof of Saturation, an algorithm for generating state spaces of concurrent systems, implemented in the SMART tool. Unlike the Breadth First Search exploration algorithm, which is easy to understand and formalise, Saturation is a complex algorithm, employing a mutually-recursive pair of procedures that compute a series of non-trivial, nested local fixed points, corresponding to a chaotic fixed point strategy. A pencil-and-paper proof of Saturation exists, but...
Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, PROGRAM VERIFICATION (COMPUTERS), STATE...
This paper details the design architecture, design methodology, and the advantages of the SpaceCube v2.0 high performance data processing system for space applications. The purpose in building the SpaceCube v2.0 system is to create a superior high performance, reconfigurable, hybrid data processing system that can be used in a multitude of applications including those that require a radiation hardened and reliable solution. The SpaceCube v2.0 system leverages seven years of board design,...
Topics: NASA Technical Reports Server (NTRS), DATA PROCESSING EQUIPMENT, COMPUTER SYSTEMS DESIGN, SMALL...
A recent history of electricity forecasting in California is given. Dealing with forecasts and regulatory uncertainty is discussed. Graphs are presented for: (1) Los Angeles Department of Water and Power and Pacific Gas and Electric present and projected reserve margins; (2) California electricity peak demand forecast; and (3) California electricity production.
Topics: NASA Technical Reports Server (NTRS), CALIFORNIA, ELECTRICITY, ENERGY CONSUMPTION, ENERGY...
A FORTRAN 4 computer code for the micromechanics, macromechanics, and laminate analysis of multilayered fiber composite structural components is described. The code can be used either individually or as a subroutine within a complex structural analysis/synthesis program. The inputs to the code are constituent materials properties, composite geometry, and loading conditions. The outputs are various properties for ply and composite; composite structural response, including bending-stretching...
Topics: NASA Technical Reports Server (NTRS), COMPOSITE MATERIALS, COMPUTER PROGRAMS, FIBERS, FORTRAN,...
The high-Al (>28 wt %), silica-poor (<45 wt %) (HASP) feldspathic glasses of Apollo 16 are widely regarded as the evaporative residues of impacts in the lunar regolith [1-3]. By virtue of their small size, apparent homogeneity, and high inferred formation temperatures, the HASP glasses appear to be good samples in which to study fractionation processes that may accompany open system evaporation. Calculations suggest that HASP glasses with present-day Al2O3 concentrations of up to...
Topics: NASA Technical Reports Server (NTRS), ALUMINUM OXIDES, MAGNESIUM ISOTOPES, SILICON ISOTOPES, LUNAR...
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The vortical structures in shear layers govern many dynamic aspects of the jet, including entrainment of mass, transfer of momentum and noise generation. These structures develop from instability waves and undergo a merging process. Vortex merging reduces the time scale and increases the length scale of the shear layer. At the same time pressure fluctuations are induced by the unsteady motion. These pressure perturbations can exert high level dynamic loading on nearby structures, and radiate to...
Topics: NASA Technical Reports Server (NTRS), JET FLOW, NEAR FIELDS, PRESSURE GRADIENTS, DYNAMIC LOADS, FAR...
The feasibility of long-range weather prediction through the use of global general circulation models (GCMs) was investigated. A climate model was developed to simulate the monthly mean state of the atmosphere from real global initial data at the beginning of the month. The model contains the same dynamic and physical ingredients as most numerical weather prediction models and GCMs. The model generates a one-day global simulation on the 8 x 10 grid in four minutes (on an IBM 360/95 computer),...
Topics: NASA Technical Reports Server (NTRS), ATMOSPHERIC MODELS, CLIMATOLOGY, LONG RANGE WEATHER...
A graphical procedure is provided for performing coordinate transformations between the geocentric-solar-equatorial, geocentric-solar-ecliptic and geocentric-solar-magnetospheric coordinate systems. The procedure is designed to facilitate intercomparison of previous studies of interactions between interplanetary and geomagnetic fields that made use of these coordinate systems. The interaction in the geocentric-solar-magnetosphere system has been shown to give the most consistent results.
Topics: NASA Technical Reports Server (NTRS), COORDINATE TRANSFORMATIONS, GEOMAGNETISM, INTERPLANETARY...
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Each of the six Apollo landers touched down at unique sites on the lunar surface. Aside from the Apollo 12 landing site located 180 meters from the Surveyor III lander, plume impingement effects on ground hardware during the landings were not a problem. The planned return to the Moon requires numerous landings at the same site. Since the top few centimeters of lunar soil are loosely packed regolith, plume impingement from the lander will eject the granular material at high velocities. A picture...
Topics: NASA Technical Reports Server (NTRS), ESTIMATES, IMPINGEMENT, PLUMES, ROCKET EXHAUST, LUNAR DUST,...
No abstract available
Topics: NASA Technical Reports Server (NTRS), ECOLOGY, POLLEN, PHENOLOGY, ENVIRONMENTAL TRANSPORT,...
Design of the two-phase systems which are anticipated to be utilized in future spacecraft thermal management systems requires a knowledge of two-phase flow and heat transfer parameters in reduced gravities. A program has been initiated by NASA to design a two-phase test loop and perform a series of experiments to generate the data for the Critical Heat Flux (CHF) and onset of instability under reduced gravities. In addition to low gravity airplane trajectory testing, the experimental program...
Topics: NASA Technical Reports Server (NTRS), HEAT FLUX, HEAT TRANSFER, MICROGRAVITY, TEMPERATURE CONTROL,...
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This volume contains an antenna location study for the P-3C aircraft. From this location study, a determination can be made of the complete antenna system required to achieve the desired pattern and polarization coverage. The antenna used is the same Batwing airborne UHF satellite communications antenna use in volume 1. The aircraft model used in the majority of the locations studied is the simple cylindrical aircraft model defined in volume 1.
Topics: NASA Technical Reports Server (NTRS), AIRCRAFT ANTENNAS, AIRCRAFT MODELS, ANTENNA DESIGN, ANTENNA...
Aerodynamic characteristics of swept wing configuration with progressive series of leading and trailing edge modifications
Topic: NASA Technical Reports Server (NTRS)
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An ion flux is directed to a carbon nanotube to permanently shape, straighten and/or bend the carbon nanotube into a desired configuration. Such carbon nanotubes have many properties that make them ideal as probes for Scanning Probe Microscopy and many other applications.
Topics: NASA Technical Reports Server (NTRS), FABRICATION, MICROSCOPY, NANOSTRUCTURES (DEVICES), FLUX...
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by NASA Technical Reports Server (NTRS)
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Space shuttle aerothermodynamic data, collected from a continuing series of wind tunnel tests, are permanently stored with the Data Management Services (DMS) system. Information pertaining to current baseline configuration definition is also stored. A list of documentation of DMS processed data arranged sequentially and by space shuttle configuration is presented. The listing provides an up to date record of all applicable aerothermodynamic data collected, processed, or summarized during the...
Topics: NASA Technical Reports Server (NTRS), AERODYNAMIC CHARACTERISTICS, AERODYNAMIC LOADS,...
A software defined radio (SDR) architecture used in space-based platforms proposes to standardize certain aspects of radio development such as interface definitions, functional control and execution, and application software and firmware development. NASA has charted a team to develop an open software defined radio hardware and software architecture to support NASA missions and determine the viability of an Agency-wide Standard. A draft concept of the proposed standard has been released and...
Topics: NASA Technical Reports Server (NTRS), AEROSPACE ENVIRONMENTS, TELECOMMUNICATION, SPACE...
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The liftoff phase induces high acoustic loading over a broad frequency range for a launch vehicle. These external acoustic environments are used in the prediction of the internal vibration responses of the vehicle and components. Present liftoff vehicle acoustic environment prediction methods utilize stationary data from previously conducted hold-down tests to generate 1/3 octave band Sound Pressure Level (SPL) spectra. In an effort to update the accuracy and quality of liftoff acoustic loading...
Topics: NASA Technical Reports Server (NTRS), ACOUSTIC MEASUREMENT, SOUND PRESSURE, NOISE SPECTRA,...
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The feasibility of using optical technology to perform the mission of the proximity operations communications subsystem on Space Station Freedom was determined. Proximity operations mission requirements are determined and the relationship to the overall operational environment of the space station is defined. From this information, the design requirements of the communication subsystem are derived. Based on these requirements, a preliminary design is developed and the feasibility of...
Topics: NASA Technical Reports Server (NTRS), MISSION PLANNING, PROXIMITY, SIGNAL PROCESSING, SPACE STATION...
A method of producing a high temperature superconductor Josephson element and an improved SNS weak link barrier element is provided. A YBaCuO superconducting electrode film is deposited on a substrate at a temperature of approximately 800 C. A weak link barrier layer of a nonsuperconducting film of N-YBaCuO is deposited over the electrode at a temperature range of 520 C. to 540 C. at a lower deposition rate. Subsequently a superconducting counter-electrode film layer of YBaCuO is deposited over...
Topics: NASA Technical Reports Server (NTRS), BARRIER LAYERS, SUPERCONDUCTIVITY, JOSEPHSON JUNCTIONS, YBCO...
If extinct and/or extant life is discovered on Mars, knowledge of the chronology of the biosphere will be of paramount importance. KArLE will provide absolute ages of Mars 2020 rocks, which will allow us to understand them in the context of Mars' geologic history, connect them to other landing sites, and compare Martian epochs of habitability with the Earth's history and evolution of life. KArLE significantly enhances the ability of Mars 2020 to meet its science objectives by performing in situ...
Topics: NASA Technical Reports Server (NTRS), GEOCHRONOLOGY, IN SITU MEASUREMENT, LASER-INDUCED BREAKDOWN...
The purpose of the two-day Workshop on Physics of Accretion Disks Around Compact and Young Stars was to bring together workers on accretion disks in the western Gulf region (Texas and Louisiana). Part 2 presents the workshop program, a list of poster presentations, and a list of workshop participants. Accretion disks are believed to surround many stars. Some of these disks form around compact stars, such as white dwarfs, neutron stars, or black holes that are members of binary systems and...
Topics: NASA Technical Reports Server (NTRS), ACCRETION DISKS, CONFERENCES, STELLAR ENVELOPES, STELLAR...
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A device for use in the production of semiconductors, characterized by etching in a rapidly rotating etching bath is described. The fast rotation causes the surface of the etching bath to assume the form of a paraboloid of revolution, so that the semiconductor wafer adjusted at a given height above the resting bath surface is only attacked by etchant at the edges.
Topics: NASA Technical Reports Server (NTRS), EDGE DISLOCATIONS, ETCHING, INVENTIONS, SEMICONDUCTORS...
Progress toward performance of the tasks and accomplishing the goals set forth in the two year Research Grant included primarily analysis of digital data sets and determination of methodology associated with the analysis of the very large, unique, and complex collection of digital solar magnetic field data. The treatment of each magnetogram as a unique set of data requiring special treatment was found to be necessary. It is determined that a person familiar with the data, the analysis system,...
Topics: NASA Technical Reports Server (NTRS), DATA REDUCTION, MAGNETIC SIGNATURES, SOLAR FLARES, SOLAR...
An apparatus and method for suppressing acoustic noise utilizes consecutive plates, closely spaced to each other so as to exploit dissipation associated with sound propagation in narrow channels to optimize the acoustic resistance at a liner surface. The closely spaced plates can be utilized as high temperature structural materials for jet engines by constructing the plates from composite materials. Geometries of the plates, such as plate depth, shape, thickness, inter-plate spacing,...
Topics: NASA Technical Reports Server (NTRS), ACOUSTICS, NOISE (SOUND), SOUND PROPAGATION, SUPPRESSORS,...
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Suspension models were used to study muscle response to reduced activity. During 6 days of tail casting, the soleus (SOL) atrophies while the extensor digitorum longus grows relatively normally. After discounting those changes in both muscles due primarily to increased secretion of adrenal hormones, the following conclusions regarding the specific responses of the SOL could be drawn: (1) Atrophy is probably due primarily to increased protein degradation; (2) Decreased synthesis of glutamine may...
Topics: NASA Technical Reports Server (NTRS), ATROPHY, MUSCULAR FATIGUE, MUSCULAR STRENGTH, MUSCULOSKELETAL...
The biconjugate gradient (BCG) method is the natural generalization of the classical conjugate gradient algorithm for Hermitian positive definite matrices to general non-Hermitian linear systems. Unfortunately, the original BCG algorithm is susceptible to possible breakdowns and numerical instabilities. A novel BCG like approach is presented called the quasi-minimal residual (QMR) method, which overcomes the problems of BCG. An implementation of QMR based on a look-ahead version of the...
Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, CONJUGATE GRADIENT METHOD, HERMITIAN POLYNOMIAL,...
The Mars Science Laboratory (MSL) spacecraft is being designed to carry a large rover (greater than 800 kg) to the surface of Mars using a blunt-body entry capsule as the primary decelerator. The spacecraft is being designed for launch in 2009 and arrival at Mars in 2010. The combination of large mass and diameter with non-zero angle-of-attack for MSL will result in unprecedented convective heating environments caused by turbulence prior to peak heating. Navier-Stokes computations predict a...
Topics: NASA Technical Reports Server (NTRS), AEROTHERMODYNAMICS, MARS SURFACE, THERMAL PROTECTION, SPACE...
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by NASA Technical Reports Server (NTRS)
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Presentation to POIWG meeting at MSFC to discuss planned operations for upcoming FFL-01 mission on SpaceX-5. Will show hardware suite used, on-orbit operations, training strategy, and data handling architecture.
Topics: NASA Technical Reports Server (NTRS), DROSOPHILA, EXPERIMENT DESIGN, INTERNATIONAL SPACE STATION,...
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by NASA Technical Reports Server (NTRS)
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The Crab is the only bright steady source in the X-ray sky. The Crab consists of a pulsar wind nebula, a synchrotron nebula, and a cloud of expanding ejecta. On small scales, the Crab is extremely complex and turbulent. X-ray astronomers have often used the Crab as a standard candle to calibrate instruments, assuming its spectrum and overall flux remains constant over time. Four instruments (Fermi/GBM, RXTE/PCA, Swift/BAT, INTEGRAL/ISGRI) show a approx.5% (50 m Crab) decline in the Crab from...
Topics: NASA Technical Reports Server (NTRS), X RAY TIMING EXPLORER, SYNCHROTRONS, PULSARS, MAGNETIC...
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Onboard digital computer and strap-down inertial reference unit for attitude control of advanced OAO
Topic: NASA Technical Reports Server (NTRS)
Sudden phase anomalies (SPA's) observed on VLF recordings are related to sudden ionospheric disturbances due to solar flares. Results are presented for SPA statistics on 500 events observed in New York during the ten year period 1961 to 1970. Signals were at 10.2kHz and 13.6kHz emitted from the OMEGA transmitters in Hawaii and Trinidad. A relationship between SPA frequency and sun spot number was observed. For sun spot number near 85, about one SPA per day will be observed somewhere in the...
Topics: NASA Technical Reports Server (NTRS), RADIO SIGNALS, SOLAR FLARES, SUDDEN IONOSPHERIC DISTURBANCES,...
Topic: NASA Technical Reports Server (NTRS)
The roles of the cryosphere, and of cloud-radiative interactions are investigated. The effects clouds and ice have in the climate system are examined. The cloud radiation research attempts explain the modes of interaction (feedback) between raditive transfer, cloud formation, and atmospheric dynamics. The role of sea ice in weather and climate is also discussed. Models are used to describe the ice and atmospheric dynamics under study.
Topics: NASA Technical Reports Server (NTRS), ATMOSPHERIC MODELS, CLIMATOLOGY, CLOUD PHYSICS, METEOROLOGY,...
The basic theory of aeroacoustics of homentropic fluid media is applied to the problems of sound scattering, production, and stimulated emission. A general theory of scattering from low speed three-dimensional vortex flows is presented. Specific results are given for the horseshoe vortex and vortex ring. The noise of an elementary corotating vortex pair in various flows is calculated. It is shown that a potential flow and shear flow can substantially increase the basic pair noise. Small reverse...
Topics: NASA Technical Reports Server (NTRS), ACOUSTIC SCATTERING, AEROACOUSTICS, BERNOULLI THEOREM, NOISE...
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Polyimide insulated electrical wire has been widely used in the aerospace industry in commercial, military, and to a lesser degree, general aviation aircraft since the early 1970s. Wiring failures linked to insulation damage have drawn much attention in the media and concerns have developed regarding the long term stability and safety of polyimide insulated electrical wire. The mechanical durability and chemical stability of polyimide insulated wire are affected by hydrolysis, notch...
Topics: NASA Technical Reports Server (NTRS), ELECTRIC WIRE, ELECTRICAL INSULATION, KAPTON (TRADEMARK), PH,...
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The response of the climate system to an external perturbation--e.g., a change in solar irradiance or a change in atmospheric opacity due to an increase in CO2--depends rather strongly on feedback processes in the system, which either amplify or dampen the effects of the initial perturbation. A simple representation of the climate system is used to compare several important feedbacks, based upon general circulation model (GCM) simulations by various investigators. The models are in general...
Topics: NASA Technical Reports Server (NTRS), ATMOSPHERIC CIRCULATION, ATMOSPHERIC COMPOSITION, ATMOSPHERIC...
This presentation covers the Airborne Science Program's goals and objectives, overview of capabilities, and recent and future actives
Topics: NASA Technical Reports Server (NTRS), REMOTE SENSING, EARTH SCIENCES, AIRBORNE EQUIPMENT, SATELLITE...
There are no author-identified significant results in this report.
Topics: NASA Technical Reports Server (NTRS), CROP IDENTIFICATION, IDAHO, IMAGERY, KANSAS, LAND USE,...
Method involves relationships between errors introduced by using finite sampling rates and parameters describing specific numerical method used. Procedurre is used in design and analysi of digital filters and simulators.
Topic: NASA Technical Reports Server (NTRS)
Numerous studies have indicated that dysregulation of the immune system occurs during or after spaceflight. Using 21 day -6 deg. head-down tilt bed rest as a spaceflight analog, this study describes the effects of artificial gravity as a daily countermeasure on immunity, stress and reactivation of clinically important latent herpes viruses. The specific aims were to evaluate psychological and physiological stress, to determine the status of the immune system and to quantify reactivation of...
Topics: NASA Technical Reports Server (NTRS), ARTIFICIAL GRAVITY, VIRUSES, IMMUNE SYSTEMS, CYTOLOGY,...
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During the Clementine 1 mission, a bistatic radar experiment measured the magnitude and polarization of the radar echo versus bistatic angle, beta, for selected lunar areas. Observations of the lunar south pole yield a same-sense polarization enhancement around beta = 0. Analysis shows that the observed enhancement is localized to the permanently shadowed regions of the lunar south pole. Radar observations of periodically solar-illuminated lunar surfaces, including the north pole, yielded no...
Topics: NASA Technical Reports Server (NTRS), MULTISTATIC RADAR, MAGNITUDE, OPTICAL POLARIZATION, WATER,...
Compact, reliable thermostat provides a temperature readout signal and a continuous temperature-control output for temperature monitoring by automatic checkout equipment or telemetry systems. It employs a solid state circuit in a housing rigidly attached to a thermistor probe.
Topic: NASA Technical Reports Server (NTRS)
Systems have been developed and demonstrated for performing quantitative velocity measurements in reduced gravity combustion science and fluid physics investigations. The unique constraints and operational environments inherent to reduced-gravity experimental facilities pose special challenges to the development of hardware and software systems. Both point and planar velocimetric capabilities are described, with particular attention being given to the development of systems to support the...
Topics: NASA Technical Reports Server (NTRS), VELOCITY DISTRIBUTION, VELOCITY MEASUREMENT, MICROGRAVITY,...
The Stratospheric Observatory for Infrared Astronomy (SOFIA) is the world's largest airborne observatory, featuring a 2.5 meter telescope housed in the aft section of a Boeing 747sp aircraft. SOFIA's current instrument suite includes: FORCAST (Faint Object InfraRed CAmera for the SOFIA Telescope), a 5-40 ┬Ám dual band imager/grism spectrometer developed at Cornell University; HIPO (High-speed Imaging Photometer for Occultations), a 0.3-1.1 micron imager built by Lowell Observatory; FLITECAM...
Topics: NASA Technical Reports Server (NTRS), SOFIA (AIRBORNE OBSERVATORY), INFRARED ASTRONOMY, AIRBORNE...
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This report derives equations containing only directly measurable constants for the quantities involved in the hydrodynamic theory of detonation. The stable detonation speed, D, is revealed as having the lowest possible value in the case of positive material velocity, by finding the minimum of the Du curve (u denotes the speed of the gases of combustion). A study of the conditions of energy and impulse in freely suspended detonating systems leads to the disclosure of a rarefaction front...
Topic: NASA Technical Reports Server (NTRS)
Laser-based Rayleigh light scattering (RLS) was performed in the National Transonic Facility (NTF) at NASA Langley Research Center. The goal was to determine if the free-stream flow undergoes clustering (early stage of condensation from gas to liquid) or remains in a pure diatomic molecular phase. Data indicate that clusters are not observable down to levels of 10% of the total light scatter for a variety of total pressures at one N2 cryogenic-mode total temperature (Tt = -50 F = 227 K) and one...
Topics: NASA Technical Reports Server (NTRS), LIGHT SCATTERING, FREE FLOW, CRYOGENIC TEMPERATURE, DIATOMIC...
In a robotic assembly project, a method was needed to accurately position a robot and a structure which the robot was to assemble. The requirements for high precision and relatively long travel distances dictated the use of cable drive systems. The design of the mechanisms used in translating the robot and in rotating the assembly under construction is discussed. The design criteria are discussed, and the effect of particular requirements on the design is noted. Finally, the measured...
Topics: NASA Technical Reports Server (NTRS), AUTOMATIC CONTROL, CABLES (ROPES), MECHANICAL DRIVES, ORBITAL...
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Characteristics of steering assembly for vehicle designed to move large components of space flight vehicles are presented. Design makes it possible to move heavy and bulky items through narrow passageways with tight turns. Typical configuration is illustrated to show dimensions of turning radius and minimum distances involved.
Topics: NASA Technical Reports Server (NTRS), CRAWLER TRACTORS, EQUIPMENT SPECIFICATIONS, MECHANICAL...
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A method has been designed for using multiple independent stations to discriminate fast transient radio sources from local anomalies, such as antenna noise or radio frequency interference (RFI). This can improve the sensitivity of incoherent detection for geographically separated stations such as the very long baseline array (VLBA), the future square kilometer array (SKA), or any other coincident observations by multiple separated receivers. The transients are short, broadband pulses of radio...
Topics: NASA Technical Reports Server (NTRS), RADIO FREQUENCY INTERFERENCE, VERY LONG BASELINE ARRAY...
We assess climate impacts of global warming using ongoing observations and paleoclimate data. We use Earth's measured energy imbalance, paleoclimate data, and simple representations of the global carbon cycle and temperature to define emission reductions needed to stabilize climate and avoid potentially disastrous impacts on today's young people, future generations, and nature. A cumulative industrial-era limit of approx.500 GtC fossil fuel emissions and 100 GtC storage in the biosphere and...
Topics: NASA Technical Reports Server (NTRS), CLIMATE CHANGE, CARBON CYCLE, FOSSIL FUELS, GLOBAL WARMING,...
Experimental results on the effect of the length-diameter ratio of the orifice on the spray characteristics, together with a brief analysis of the factors affecting these characteristics, are presented in this report. The length-diameter ratios tested ranged from 0.5 to 10; the orifice diameters from 0.008 to 0.040 inch; and the injection pressures from 2,000 to 8,000 pounds per square inch. The density of the air into which the fuel was discharged was varied from 0.38 to 1.35 pounds per cubic...
Topic: NASA Technical Reports Server (NTRS)
The changing marketplace as evidenced by global competition is requiring American organizations to rethink, regroup, and redesign their processes. The umbrella of total quality management (TQM) includes many quality methods, techniques, tools, and approaches. There is no right way for every situation or circumstance. Adaptability and experimentation of several tools is necessary. Process management when properly applied can lead to continuous quality improvements. But some processes simply need...
Topics: NASA Technical Reports Server (NTRS), TOTAL QUALITY MANAGEMENT, MANAGEMENT METHODS, RELIABILITY...
An extensive test and analytical effort has been completed by the Space Shuttle's Reusable Solid Rocket Motor (KSKM) nozzle program to characterize the failure behavior of two epoxy adhesives (TIGA 321 and EA946). As part of this effort, a general failure model, the "Multi-Axial, Temperature, and Time Dependent" or MATT failure criterion was developed. In the initial development of this failure criterion, tests were conducted to provide validation of the theory under a wide range of...
Topics: NASA Technical Reports Server (NTRS), FAILURE ANALYSIS, EPOXY RESINS, ADHESIVES, TEMPERATURE...
Due to particle sedimentation and relatively low laminar flame speeds in dust suspensions, microgravity environment is essential for the observation of laminar dust flames in a wide range of particle sizes and fuel concentrations [1]. The capability of a reduced-gravity environment to facilitate study of dust combustion was realized by researchers long before current microgravity programs were established by the various national Space Agencies. Thus, several experimentalists even built their...
Topics: NASA Technical Reports Server (NTRS), MICROGRAVITY, DUST, COMBUSTION, FLAME PROPAGATION, METAL...
Derivation of International Geomagnetic Reference Field with tables of spherical harmonic coefficients and test results of various magnetic field models
Topic: NASA Technical Reports Server (NTRS)
Results from a seminar on the role of solar magnetic fields in determining the structure of the corona and interplanetary medium are presented. Some topics considered are: (1) polar regions of the sun which have identical magnetic configurations but display a vastly different appearance in the corona, (2) the influence of latitude on coronal and interplanetary microstructure, and (3) the role of the corona in contributing to the solar wind. It is proposed that an out-of-the-ecliptic solar probe...
Topics: NASA Technical Reports Server (NTRS), ECLIPTIC, SOLAR CORONA, SOLAR MAGNETIC FIELD, SPACE MISSIONS,...
In January 1989, a mishap occurred in the National Transonic Facility wind tunnel at NASA-Langley. It is believed that the failure of an insulation retainer holding foam insulation around the exterior of the fan drive shaft resulted in the subsequent damage to other components in the tunnel. The effect was determined of removing the external thermal insulation on the shaft would have on the stresses on the shaft, disk and bolts holding the two together. To accomplish this, a detailed...
Topics: NASA Technical Reports Server (NTRS), FAILURE ANALYSIS, FAN BLADES, FINITE ELEMENT METHOD, SHAFTS...
No abstract available
Topic: NASA Technical Reports Server (NTRS)
The chemical compositions of soils and rocks from the Pathfinder site and Phobos-2 orbital gamma-ray spectroscopy indicate that the Martian crust has a bulk composition equivalent to large-ion lithophile (LIL) and heat-producing element (HPE) enriched basalt, with a potassium content of about 0.5%. A variety of radiogenic isotopic data also suggest that separation of LIL-enriched crustal and depleted mantle reservoirs took place very early in Martian history (greater than 4.0 Ga). Accordingly,...
Topics: NASA Technical Reports Server (NTRS), MARS SURFACE, PLANETARY GEOLOGY, PLANETARY CRUSTS, PLANETARY...
This paper describes improved methods of calculating wall interference corrections for the ONERA large windtunnels. The mathematical description of the model and its sting support have become more sophisticated. An increasing number of singularities is used until an agreement between theoretical and experimental signatures of the model and sting on the walls of the closed test section is obtained. The singularity decentering effects are calculated when the model reaches large angles of attack....
Topics: NASA Technical Reports Server (NTRS), INTERFERENCE DRAG, ITERATION, MACH NUMBER, WIND TUNNEL TESTS,...
The mathematical theory of the computational algorithms employed in the onboard navigation package system is described. This system, which simulates an onboard navigation processor, was developed to aid in the design and evaluation of onboard navigation software. The mathematical formulations presented include the factorized UDU(T) form of the extended Kalman filter, the equations of motion of the user satellite, the user clock equations, the observation equations and their partial derivatives,...
Topics: NASA Technical Reports Server (NTRS), COMPUTER PROGRAMS, MATHEMATICAL MODELS, ONBOARD DATA...
Tests were conducted to determine the feasibility of using an adaptive ground implemented phased array (AGIPA) to overcome the limitations of the radio frequency interference limited low data Tracking and Data Relay Satellite VHF return link. A feasibility demonstration model of a single user channel AFIPA system was designed, developed, fabricated, and evaluated. By scaling the frequency and aperture geometry from VHF to S-band, the system performance was more easily demonstrated in the...
Topics: NASA Technical Reports Server (NTRS), PHASED ARRAYS, RADIO COMMUNICATION, TDR SATELLITES, VERY HIGH...
This paper presents a three-dimensional (3-D) 'edge-swapping method based on local transformations. This method extends Lawson's edge-swapping algorithm into 3-D. The 3-D edge-swapping algorithm is employed for the purpose of refining and optimizing unstructured meshes according to arbitrary mesh-quality measures. Several criteria including Delaunay triangulations are examined. Extensions from two to three dimensions of several known properties of Delaunay triangulations are also discussed.
Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, COMPUTATIONAL FLUID DYNAMICS, COMPUTATIONAL...
Pressure distribution and bubble formation induced by longitudinal vibration of flexible liquid- filled cylinder
Topic: NASA Technical Reports Server (NTRS)
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The HOST Liner Cyclic Program is utilizing two types of test apparatus, rectangular box rigs and a full annular rig. To date two quartz lamp cyclic box rigs have been tested and a third is to begin testing in late October 1983. The box rigs are used to evaluate 5x8 inch rectangular linear samples. A 21 inch diameter outer liner simulator is also being built up for testing beginning in April 1984. All rigs are atmospheric rigs. The first box rig, a three 6-kVA lamp installation, was operated...
Topics: NASA Technical Reports Server (NTRS), COMBUSTION CHAMBERS, DEPOSITION, EXHAUST EMISSION, GAS...
Wind tunnel evaluation of Apache model aerodynamic stability and control characteristics
Topic: NASA Technical Reports Server (NTRS)
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Digital Globe provides for general use 2.4 m multi-spectral and 0.7 m panchromatic imagery acquired by the Quickbird satellite. This geometrically corrected imagery was obtained as standard and orthorectified products; the difference between the two products is primarily in the degree of geometric accuracy that Digital Globe claims. For both products, every image pixel contains estimated sets of Northing/Easting and lat/long coordinates accessible through an image display application such as...
Topics: NASA Technical Reports Server (NTRS), GEOMETRIC ACCURACY, IMAGERY, COORDINATES, ESTIMATING, GROUND...