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At least 955 records · Page 53
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Data availability and the role of the earth resources observation systems data center

With the launch of LANDSAT-1 in July 1972, and the follow-on launch of LANDSAT-2 in January of this year, routine availability of satellite imagery and electronic data of the earth's resources has become a reality. Federal data centers provide LANDSAT data to resource managers and the general public. These data centers have to date provided almost 500,000 frames of LANDSAT data at a cost of more than $2,000,000. Data from the LANDSAT satellite program, along with data and information from the Skylab manned program, are available over any location to anyone for the cost of reproduction.

Watkins, A. H.↗
NASA NTRS1975

Interactive image processing for meteorological applications at NASA/Goddard Space Flight Center

The meteorological data processing program at the space center is centered on the analysis of geostationary satellite data. Its objectives are to detect and predict severe storms, to improve short range and long range global numerical weather forecasting models, and to develop improved satellite systems. The Image Display and Manipulation System (IDAMS) for earth resources satellite data processing is described, as is the special purpose software package, METPAK, for performing meteorology operations on IDAMS. The Atmospheric and Oceanographic Information Processing System (AOIPS), a dual terminal multiprocessor is also described.

Billingsley, J. B.↗
NASA NTRS1975

Digital image centering. I

A series of parallax plates have been measured on a PDS microdensitometer to assess the possibility of using the PDS for precision relative astrometry and to investigate centering algorithms that might be used to analyze digital images obtained with the Large Space Telescope. The basic repeatability of the PDS is found to be plus or minus 0.6 micron, with the potential for reaching plus or minus 0.2 micron. A very efficient centering algorithm has been developed which fits the marginal density distributions of the image with a Gaussian profile and a sloping background. The accuracy is comparable with the best results obtained with a photoelectric image bisector.

Van Altena, W. F.↗
NASA NTRS1975

Mass center estimation of a drag-free satellite

The mass center location of a spinning drag-free satellite can be estimated because there is control required to accelerate the mass center along the axis of spin as long as there is some nutation in the spinning motion. Linear and nonlinear models are compared and observability discussed. Online estimation fails when nutation is damped so an offline mechanization is proposed. A new sensor has been designed to permit greater relative motion than was possible on the drag-free satellite flown in 1972 (JH-1). Experimental laboratory results using a spinning vehicle with the new sensor mounted 30 cm from a spherical air bearing support are presented which confirm earlier simulation results.

Sanz Fernandez De Cordova, S.↗
NASA NTRS1976

Meteorological regimes for the classification of aerospace air quality predictions for NASA-Kennedy Space Center

A method is described for developing a statistical air quality assessment for the launch of an aerospace vehicle from the Kennedy Space Center in terms of existing climatological data sets. The procedure can be refined as developing meteorological conditions are identified for use with the NASA-Marshall Space Flight Center Rocket Exhaust Effluent Diffusion (REED) description. Classical climatological regimes for the long range analysis can be narrowed as the synoptic and mesoscale structure is identified. Only broad synoptic regimes are identified at this stage of analysis. As the statistical data matrix is developed, synoptic regimes will be refined in terms of the resulting eigenvectors as applicable to aerospace air quality predictions.

Stephens, J. B.↗
NASA NTRS1976

A study of the remote neighborhood office center concept

The substitution of communications for commuting to work is examined from several aspects. Attention is focused on the possibility of certain groups of white collar workers conducting their business affairs through a network of Remote Neighborhood Office Centers (RNOC's) located near their homes. Typically, employees would communicate with their headquarters organizations by means of voice and digital circuits. Although current technology is readily able to support such an RNOC network, the main problems confronting would-be implementers center around the need for demonstrating that a sufficient number of business operations can be carried out in such a decentralized configuration as efficiently as they are under more conventional circumstances. The description of a pilot program is presented which is intended to identify pacing issues that must be settled before firm conclusions can be reached on whether the concept is operationally viable.

Source record↗
NASA NTRS1977

Measurements of the reaction e/+/e/-/ yielding gamma-gamma at center-of-mass energies in the range 6.2-7.4 GeV

The cross section for the pair-annihilation reaction e(+)e(-) yields gamma-gamma were measured at center-of-mass energies in the range 6.2-7.4 GeV and at production angles close to 90 deg. The experimental apparatus consisted of two identical spectrometers which were set to view the luminous region at SPEAR-II from opposite directions at an azimuthal angle of 45 deg. In each spectrometer there was a NaI(TI) crystal 20 radiation lengths thick and 30 in. in diameter to measure the gamma-ray energies. Annihilation events were detected by an electronic trigger which required only the observation in coincidence of more than 0.2 GeV in each NaI(TI) crystal within + or - 15 nsec of the crossing beams. The observed rates of pair-annihilation events were found to be in agreement with those expected from quantum electrodynamics (QED) at all the center-of-mass energies used.

Hilger, E.↗
NASA NTRS1976

An Ecological Study of the Lagoons Surrounding the John F. Kennedy Space Center, Brevard County, Florida: Experimental Results and Conclusions - Volume I

The studies reported here are the result of a three year effort to define the major biological, microbiological, chemical and geological characteristics of the water of the Indian River lagoon around the Kennedy Space Center and to determine the movements of those waters within and between the various basins. This work was the result of a jointly funded agreement between the Florida Institute of Technology and John F. Kennedy Space Center, NASA under NASA Grant NGR 10-015-008, dated April 11, 1972. This cost sharing grant was renewed for each of two successive years. Sampling operations were terminated August 31, 1975.

Nevin, T. A.↗
NASA NTRS1977

Effects of defect recombination centers on radiation damage in solar cells

Defect production in silicon is modeled on a computer by solving a large system of rate equations. The model includes the main, known defects that are stable at operating temperatures of solar cells in outer space; most of these defects are secondary and tertiary defects. The preliminary result shows that the presence of defect recombination centers for primary defects (i.e., vacancy and interstitial) can effectively reduce the production rates of those stable defects and, consequentially, improve the lifetime of solar cells operating in radiation environment. The characteristics of the defect recombination center required for better solar cell performance along with prospective candidates are discussed.

Cheng, L. J.↗
NASA NTRS1978

Ground winds for Kennedy Space Center, Florida (1978 version)

Ground level runway wind statistics are presented for the Kennedy Space Center, Florida area. Crosswind, headwind, tailwind, and headwind reversal percentage frequencies are given with respect to month and hour for the Kennedy Space Center Space Shuttle runway. This document supersedes NASA CR-128995 and should be used in place of it.

Johnson, D. L.↗
NASA NTRS1978

Rice University observations of the galactic center

The most sensitive of the four balloon fight observations of the galactic center made by Rice University was conducted in 1974 from Rio Cuarto, Argentina at a float altitude of 4 mbar. The count rate spectrum of the observed background and the energy spectrum of the galactic center region are discussed. The detector used consists of a 6 inch Nal(T 1ambda) central detector collimated to approximately 15 deg FWHM by a Nal(T lamdba) anticoincidence shield. The shield in at least two interaction mean free paths thick at all gamma ray energies. The instrumental resolution is approximately 11% FWHM at 662 keV. Pulses from the central detector are analyzed by two 256 channel PHA's covering the energy range approximately 20 keV to approximately 12 MeV. The detector is equatorially mounted and pointed by command from the ground. Observations are made by measuring source and background alternately for 10 minute periods. Background is measured by rotating the detector 180 deg about the azimuthal axis.

Meegan, C. A.↗
NASA NTRS1978

The effect of seawater on thermoregulator centers

Experiments were done on dogs to determine the mechanism of thermoregulation. Results show that natural seawater, injected intravenously (150, 200, and 300 cc ), causes narcosis of the thermic centers and increases temperature. Diluted seawater injection causes an excitation of the thermic centers and an antipyretic effect.

Dontas, S.↗
NASA NTRS1978

Technology utilization in a non-urban region: Further impact and technique of the Technology Use Center

Performance information for the center is reported. The search production during the reporting period exceeds the production record of the center during any period in its 14 year history. A performance average of 30 searches per month, which represents an increase of 45%, is reported. Numerical listings of the searches processed are given. A section of transfer and impact report is included.

Gold, C. H.↗
NASA NTRS1978

Submillimeter observations of the galactic center

A 15 by 15 arcmin region surrounding Sgr A has been mapped at a mean wavelength of 540 microns. The principal feature is a ridge about 10 arcmin long running parallel to the galactic equator and approximately centered on Sgr A but with no peak at that point. The ridge coincides with the 25- and 55-km/s clouds seen in molecular line observations. The mass of the clouds is estimated, and their positions with respect to the galactic center are discussed.

Hildebrand, R. H.↗
NASA NTRS1978

Infrared observations of the galactic center. III - 2.2 micron spectroscopy

Observations of the B-gamma line at 2.17 microns are presented for the central few parsecs of the galactic-center region. The surface-brightness distribution of the line with 3.3- and 6.6-arcsec resolution has been sampled in 25 locations. The results show that the ionized gas is concentrated within the central parsec of the galactic-center region; the fine-scale structure seen at 10 microns does not appear to be present in the ionized gas. For the central parsec (20 arcsec) the equivalent width of the B-gamma line is, within large uncertainties, independent of the 2-micron continuum flux; for radial distances of the order of 30 arcsec the line equivalent width drops significantly. A comparison of the B-gamma line strength with radio observations shows that the 2.2-micron extinction is consistent with the 2.7 mag determined from the reddening of late-type stars. Observations of the CO band at 2.3 microns in the central 30 arcsec are also presented; they strengthen the interpretation that the 2-micron flux arises from late-type giant stars.

Neugebauer, G.↗
NASA NTRS1978

The solar XUV He I and He II emission lines. I - Intensities and gross center-to-limb behavior

The center-to-limb variation of the He II 304- and 256-A lines and He I 584- and 537-A lines is derived for different solar features, but averaged over the chromospheric supergranulation structure. The general trend is for limb brightening in quiet-sun regions, limb neutrality in unipolar magnetic regions (UMR), and limb darkening in polar coronal holes. The center-to-limb behavior in these optically thick emission lines indicates collisional excitation and decreasing transition-region temperature gradients with respect to optical depth in the sequence quiet sun to UMR to coronal hole.

Mango, S. A.↗
NASA NTRS1978

Far-infrared observations of H II regions near the galactic center

This paper presents and discusses far-infrared observations of nine H II regions within 1 deg of the galactic center, including Sgr A, Sgr B2, Sgr C, and G0.5-0.0. The far-infrared luminosity, color temperature, and optical depth of these regions and the ratio of infrared flux to radio-continuum flux lie in the range characteristic of spiral-arm H II regions. The far-infrared results are therefore consistent with the idea that the galactic-center H II regions are ionized by luminous early-type stars. Steep systematic gradients in far-infrared color temperature and optical depth are seen along the galactic plane between Sgr B2 and G0.5-0.0; the appearance of this area is similar to that of regions of star formation in the spiral arms.

Gatley, I.↗
NASA NTRS1978

Infrared observations of the galactic center. IV - The interstellar extinction

Infrared observations of the compact sources and background in the galactic center are used to derive the 1.25-12.5-micron interstellar extinction law. The depth of the interstellar 10-micron silicate absorption feature is derived from observations of the M supergiant IRS 7. The ratio of visual to silicate extinction is found to be 8 + or - 3. From the colors of individual sources and the background, it is concluded that there are no more than 6 mag of visual extinction within the central 3 pc of the galactic center.

Becklin, E. E.↗