Meteoroid detector
A meteoroid detector is described which uses, a cold cathode discharge tube with a gas-pressurized cell in space for recording a meteoroid puncture of the cell and for determining the size of the puncture.
Mcmaster, L. R.↗
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Results for “SIZE DETERMINATION”
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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Economical technique for fragmentation testing
Automatic rifle was modified for remote, single-shot use. To simulate statistically--determined fragment size from rocket-motor casing blunt-nosed bullet was made of same alloy. Cartridge was loaded with enough powder to make bullet reach target at same estimated velocity as shrapnel from rocket casing.
Smith, T. H., III↗
Evaluation by step response tests of prototype relief valves designed for YF-12 inlet stability bleed system
Two stability bleed system relief valves were tested in a special dynamic test facility. These poppet valves are prototypes for a stability bleed system designed for use in a YF-12 flight inlet. One valve is unshielded, while the other has a special shield to eliminate the flow effect pressures on the piston. The tests determined the size of a damping orifice to be used during wind tunnel tests of the bleed system and verified an analog simulation of the valves. The effects of initial pressure level, pressure step size, and spring rate were investigated.
Dustin, M. O.↗
Structural optimization with flutter speed constraints using maximized step size
A procedure is presented for the minimization of structural mass while satisfying flutter speed constraints. The procedure differs from other optimization methods in that the flutter speed is exactly satisfied at each resizing step, and the step size is determined by a direct minimization of the objective function (mass) for each set of flutter derivatives calculated. In conjunction with this method, a new move vector is suggested which results in a very efficient resizing procedure.
Oconnell, R. F.↗
On Similarity Transformation and Geodetic Network Distortions Based on Doppler Satellite Observations
Models used in geodesy to transform two sets of coordinates are studied and distortions in geodetic networks are investigated. Commonly used transformation models are first reviewed and most of them are interpreted. Differences between various models are discussed. Pitfalls in partial solutions are then considered. It is shown that only as many chords and/or directional elements can be used in the computation as are needed to completely determine the size or shape of the polyhedron implied in the set of Cartesian coordinates. Each additional element causes the normal matrix to be singular provided that all correlations between the chords are used. A number of tables and maps indicating distortions in the NAD 27, Precise Traverse M-R '72, AUS, and SAD 69 geodetic datums are also included. The residuals of the coordinates are scanned for systematic patterns after transforming each geodetic system to the NWL9D Doppler system. Also, an attempt is made to show scale distortions in the NAD 27.
Leick, Alfred↗
The requirements for batteries for electric vehicles
The paper reassesses the role of electric vehicles in the modern transportation system and their potential impact on oil consumption. Three major factors determining the size of this impact are discussed: the market potential, the date of introduction, and the rate of consumer acceptance. The strategy of selecting the battery type for an urban car to introduce in coming years is analyzed. The results of the analysis suggest that the research and development emphasis should be placed on near- and mid-term battery technology. From the standpoint of maximizing both the cumulative impact and the benefits derived in the year 2000, however, a strategy of early introduction of near-term and mid-term cars followed by the far-term vehicles seems to produce the optimum result.
Schwartz, H. J.↗
Advanced Earth Observation System Instrumentation Study (AEOSIS)
The feasibility, practicality, and cost are investigated for establishing a national system or grid of artificial landmarks suitable for automated (near real time) recognition in the multispectral scanner imagery data from an earth observation satellite (EOS). The intended use of such landmarks, for orbit determination and improved mapping accuracy is reviewed. The desirability of using xenon searchlight landmarks for this purpose is explored theoretically and by means of experimental results obtained with LANDSAT 1 and LANDSAT 2. These results are used, in conjunction with the demonstrated efficiency of an automated detection scheme, to determine the size and cost of a xenon searchlight that would be suitable for an EOS Searchlight Landmark Station (SLS), and to facilitate the development of a conceptual design for an automated and environmentally protected EOS SLS.
Var, R. E.↗
Hybrid receiver study
The results are presented of a 4 month study to design a hybrid analog/digital receiver for outer planet mission probe communication links. The scope of this study includes functional design of the receiver; comparisons between analog and digital processing; hardware tradeoffs for key components including frequency generators, A/D converters, and digital processors; development and simulation of the processing algorithms for acquisition, tracking, and demodulation; and detailed design of the receiver in order to determine its size, weight, power, reliability, and radiation hardness. In addition, an evaluation was made of the receiver's capabilities to perform accurate measurement of signal strength and frequency for radio science missions.
Stone, M. S.↗
On the problems associated with the rapidly varying compact nonthermal sources
Difficulties and possible interpretations are discussed for observations of extragalactic compact nonthermal radio sources. The sources considered are those which have been identified optically with normal and peculiar galaxies, quasars, N galaxies, and BL Lacertae objects. Optical, infrared, and radio flux variations in different sources are noted along with difficulties associated with determining angular sizes from interferometric measurements. It is suggested that the ultimate origin of the infrared flux is probably a nonthermal synchrotron mechanism in some sources and absorption and reradiation of ultraviolet synchrotron radiation by dust in others. Model calculations of compact sources are reviewed, emphasizing equipartition of energy, total energies, the importance of the Compton effect, and sources which present severe difficulties for the theory of a canonical incoherent electron-synchrotron source.
Burbidge, G. R.↗
Skylab/EREP application to ecological, geological, and oceanographic investigations of Delaware Bay
The author has identified the following significant results. Skylab/EREP S190A and S190B film products were optically enhanced and visually interpreted to extract data suitable for mapping coastal land use; inventorying wetlands vegetation; monitoring tidal conditions; observing suspended sediment patterns; charting surface currents; locating coastal fronts and water mass boundaries; monitoring industrial and municipal waste dumps in the ocean; and determining the size and flow direction of river, bay, and man-made discharge plumes. Film products were visually analyzed to identify and map ten land use and vegetation categories at a scale of 1:125,000. Thematic maps were compared with CARETS land use maps, resulting in classification accuracies of 50 to 98%. Digital tapes from S192 were used to prepare thematic land use maps. The resolutions of the S190A, S190B, and S192 systems were 20-40m, 10-20m, and 70-100m, respectively.
Klemas, V.↗
Skylab/EREP application to ecological, geological, and oceanographic investigations of Delaware Bay
Skylab/EREP S190A and S190B film products were optically enhanced and visually interpreted to extract data suitable for; (1) mapping coastal land use; (2) inventorying wetlands vegetation; (3) monitoring tidal conditions; (4) observing suspended sediment patterns; (5) charting surface currents; (6) locating coastal fronts and water mass boundaries; (7) monitoring industrial and municipal waste dumps in the ocean; (8) determining the size and flow direction of river, bay and man-made discharge plumes; and (9) observing ship traffic. Film products were visually analyzed to identify and map ten land-use and vegetation categories at a scale of 1:125,000. Digital tapes from the multispectral scanner were used to prepare thematic maps of land use. Classification accuracies obtained by comparison of derived thematic maps of land-use with USGS-CARETS land-use maps in southern Delaware ranged from 44 percent to 100 percent.
Klemas, V.↗
The effect of technology advancements on the comparative advantages of electric versus chemical propulsion for a large cargo orbit transfer vehicle
Techniques for sizing electrically or chemically propelled orbit transfer vehicles and analyzing fleet requirements are used in a comparative analysis of the two concepts for various levels of traffic to geosynchronous orbit. The vehicle masses, fuel requirements, and fleet sizes are determined and translated into launch vehicle payload requirements. Technology projections beyond normal growth are made and their effect on the comparative advantages of the concepts is determined. A preliminary cost analysis indicates that although electric propulsion greatly reduces launch vehicle requirements substantial improvements in the cost and reusability of power systems must occur to make an electrically propelled vehicle competitive.
Rehder, J. J.↗
VORTAB - A data-tablet method of developing input data for the VORLAX program
A method of developing an input data file for use in the aerodynamic analysis of a complete airplane with the VORLAX computer program is described. The hardware consists of an interactive graphics terminal equipped with a graphics tablet. Software includes graphics routines from the Tektronix PLOT 10 package as well as the VORTAB program described. The user determines the size and location of each of the major panels for the aircraft before using the program. Data is entered both from the terminal keyboard and the graphics tablet. The size of the resulting data file is dependent on the complexity of the model and can vary from ten to several hundred card images. After the data are entered, two programs READB and PLOTB, are executed which plot the configuration allowing visual inspection of the model.
Denn, F. M.↗
Estimation of tunnel blockage from wall pressure signatures: A review and data correlation
A method is described for estimating low speed wind tunnel blockage, including model volume, bubble separation and viscous wake effects. A tunnel-centerline, source/sink distribution is derived from measured wall pressure signatures using fast algorithms to solve the inverse problem in three dimensions. Blockage may then be computed throughout the test volume. Correlations using scaled models or tests in two tunnels were made in all cases. In many cases model reference area exceeded 10% of the tunnel cross-sectional area. Good correlations were obtained regarding model surface pressures, lift drag and pitching moment. It is shown that blockage-induced velocity variations across the test section are relatively unimportant but axial gradients should be considered when model size is determined.
Hackett, J. E.↗
Monitoring of particulate contamination and background brightness from IECM based instrumentation
Of particular concern to the astronomical community is the effect of Shuttle Transportation System induced contamination in the form of individual particles and general background on astronomical experiments. In an effort to investigate this problem, two camera/photometers in the Induced Environment Contamination Monitor (IECM) will be used to determine the size and velocity distribution of contaminant particles, their origin, and the extent of sunlit background brightness resulting from spacecraft contamination. The cameras will operate synchronously as a stereo pair to make continuous photographic measurements throughout the missions.
Clifton, K. S.↗
Infrared heterodyne interferometry
The possibilities for infrared heterodyne interferometry are examined. First the characteristics of atmospheric seeing in the infrared are considered, in order to determine the sizes of collecting apertures and baselines which can be used for relatively simple interferometers. The advantages of heterodyne over direct detection are pointed out. For example, when long baselines are used, the narrow bandwidth of heterodyne detection makes matching the path lengths easier. Experimental results on the spatial distribution of warm dust around stars and on astrometric precision obtained with prototype systems are given. Telescope design for a heterodyne interferometer is discussed.
Townes, C. H.↗
Space reflector technology and its system implications
The technical feasibility of providing nearly continuous solar energy to a world-distributed set of conversion sites by means of a system of orbiting, large-area, low-areal-density reflecting structures is examined. Requisite mirror area to provide a chosen, year-averaged site intensity is shown. A modeled reflector structure, with suitable planarity and ability to meet operational torques and loads, is discussed. Typical spatial and temporal insolation profiles are presented. These determine the sizing of components and the output electric power from a baselined photovoltaic conversion system. Technical and economic challenges which, if met, would allow the system to provide a large fraction of future world energy needs at costs competitive to circa-1995 fossil and nuclear sources are discussed.
Billman, K. W.↗
Determination of moments of the size distribution function in scattering by polydispersions - A comment
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Fymat, A. L.↗