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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,441 records · Page 80
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NASA NTRS1975

Apollo experience report: Flight anomaly resolution

The identification of flight anomalies, the determination of their causes, and the approaches taken for corrective action are described. Interrelationships of the broad range of disciplines involved with the complex systems and the team concept employed to ensure timely and accurate resolution of anomalies are discussed. The documentation techniques and the techniques for management of anomaly resolution are included. Examples of specific anomalies are presented in the original form of their progressive documentation. Flight anomaly resolution functioned as a part of the real-time mission support and postflight testing, and results were included in the postflight documentation.

Lobb, J. D.↗
NASA NTRS1975

Spectral and spatial resolution of the 12.8 micron Ne 2 emission from the galactic center

High-resolution spectra of the Ne II 12.8 micron fine-structure line in emission from the galactic center cloud Sgr A West show a line-center LSR radial velocity of + 75 + or - 20 km/sec. and a velocity dispersion of about 200 km/sec. The line has been observed with spectral resolution as high as 0.10/cm and spatial resolution as high as 8 sec. This appears to provide a direct measurement of conditions in the 45 sec. ionized region at the galactic center. The radial velocity and dispersion are more-or-less independent of position and indicate that events as recent as the last 4 million years have given the ionized gas a systematic motion with respect to the massive stellar component of material at the galactic center. An upper limit for the mass approximately equal to four million times the solar mass was obtained from the velocity distribution, with the mass located within 0.8 parsecs of the galactic center.

Wollman, E. R.↗
NASA NTRS1975

High resolution frequency analysis techniques with application to the redshift experiment

High resolution frequency analysis methods, with application to the gravitational probe redshift experiment, are discussed. For this experiment a resolution of .00001 Hz is required to measure a slowly varying, low frequency signal of approximately 1 Hz. Major building blocks include fast Fourier transform, discrete Fourier transform, Lagrange interpolation, golden section search, and adaptive matched filter technique. Accuracy, resolution, and computer effort of these methods are investigated, including test runs on an IBM 360/65 computer.

Decher, R.↗
NASA NTRS1975

High resolution spectrograph

The high resolution spectrograph (HRS) is designed to be used with the Large Space Telescope (LST) for the study of spectra of point and extended targets in the spectral range 110 to 410 nm. It has spectral resolutions of 1,000; 30,000; and 100,000 and has a field of view as large as 10 arc sec. The spectral range and resolution are selectable using interchangeable optical components and an echelle spectrograph is used to display a cross dispersed spectrum on the photocathode of either of 2 SEC orthicon image tubes. Provisions are included for wavelength calibration, target identification and acquisition and thermal control. The system considerations of the instrument are described.

Peacock, K.↗
NASA NTRS1976

Spectral and spatial resolution of the 12.8 micron Ne II emission from the galactic center

High-resolution spectra of the Ne II 12.8-micron fine-structure line in emission from the galactic-center cloud Sgr A West show a line-center LSR radial velocity of +75 (+ or - 20) km/s and a velocity dispersion of about 200 km/s. The line has been observed with spectral resolution as high as 0.10 micron/cm and spatial resolution as high as 8 arcsec. This appears to provide a direct measurement of conditions in the 45-arcsec ionized region at the galactic center. The radial velocity and dispersion are more or less independent of position and indicate that events as recent as the last 10,000 years have given the ionized gas a systematic motion with respect to the massive stellar component of material at the galactic center. An upper limit of the order of 4 million solar masses for the mass within 0.8 pc of the galactic center is obtained from the velocity dispersion.

Wollman, E. R.↗
NASA NTRS1977

Upgrading and testing program for narrow band high resolution planetary IR imaging spectrometer

An imaging spectrometer, intended primarily for observations of the outer planets, which utilizes an acoustically tuned optical filter (ATOF) and a charge coupled device (CCD) television camera was modified to improve spatial resolution and sensitivity. The upgraded instrument was a spatial resolving power of approximately 1 arc second, as defined by an f/7 beam at the CCD position and it has this resolution over the 50 arc second field of view. Less vignetting occurs and sensitivity is four times greater. The spectral resolution of 15 A over the wavelength interval 6500 A - 11,000 A is unchanged. Mechanical utility has been increased by the use of a honeycomb optical table, mechanically rigid yet adjustable optical component mounts, and a camera focus translation stage. The upgraded instrument was used to observe Venus and Saturn.

Wattson, R. B.↗
NASA NTRS1977

High resolution infrared absorptivities for gaseous chlorine nitrate

High resolution infrared absorptivities of chlorine nitrate (ClONO2) are required in order to quantitatively evaluate, by examination of infrared spectra obtained recently from balloon-borne spectrometers, the possible occurrence of this compound in the stratosphere. In the present study, infrared absorptivities for four absorption bands of gaseous ClONO2 have been measured at 0.0625 per cm spectral resolution with a Fourier transform infrared (FT-IR) system. Spectra were obtained at two pressures (0.05 and 1.05 torr) of pure ClONO2 and with 125 torr of N2 added to a 0.50 torr sample. Absorptivities for a range of spectral resolutions (0.0625, 0.125, 0.25 and 0.50 per cm) have been calculated from the data.

Graham, R. A.↗
NASA NTRS1977

High-resolution observations of the Lyman alpha sky background

The first high-resolution observations of the Lyman alpha sky background, obtained with a spectrometer on the Copernicus satellite, are examined. The high-resolution observations presented allow the first direct measurement of the heliocentric velocity of the local interstellar medium. The high resolution of the spectrometer and the projection of the earth's orbital velocity along the line of sight made it possible to separate the weak extraterrestrial background feature from the intense geocoronal emission line. The observations also contain considerable information about the Lyman alpha emission from the geocorona. The data permit limits to be placed on the temperature of the gas that produces the background feature.

Adams, T. F.↗
NASA NTRS1978

The analysis of high spatial resolution UV and X-ray images by computational modeling

Very high resolution stereoscopic images of high temperature loop structures observed at UV and X-ray wavelengths in the solar corona can be used to understand physical processes in the corona. An existing computational model is described and sample results are given to demonstrate that computational modeling of coronal structures can indeed take advantage of very high resolution images. The sample results include the run of temperature and number density along a typical loop and the variation of the differential emission measure with temperature. The integration of the differential emission measure with temperature along a column commensurate with an instrument's spatial resolution is the relevant parameter obtained from UV and X-ray observations. The effects of loop geometry and energy input are examined.

Vesecky, J. F.↗
NASA NTRS1977

Investigation of thematic mapper spatial, radiometric, and spectral resolution

Low-altitude aircraft scanner data were employed in simulating the spatial resolution, radiometric sensitivity and spectral bandwidth parameters of the proposed Landsat Thematic Mapper (TM). The 30 to 40 m resolution of the TM was found to provide significant improvement over current Landsat resolution (50 to 60 m) in crop mensuration, especially for Western Europe and India where field sizes average from one to four hectares. In terms of radiometric sensitivity, a noise equivalent reflectance value of 0.5% was held to be necessary for discrimination of spectrally similar data; in addition, all of the six proposed TM spectral bands were shown to be necessary for monitoring at some point during the growing season.

Morgenstern, J. P.↗
NASA NTRS1977

The effect of increased horizontal resolution on synoptic forecasts with the GISS model of the global atmosphere

The improved horizontal resolution global circulation model in question has a horizontal spacing of 2.5 deg latitude by 3 deg longitude for a resolution of about 250 km in midlatitude. This paper reports on experiments to determine the improvements in forecasting skill and in initial conditions that were made possible by the ultrafine resolution and ultrafine assimilation. The size of the improvement in skill score when the ultrafine model is used for forecasting and assimilation was so large that 60-hour forecasts with the ultrafine model had as good a skill score as the 48-hour forecasts with the fine model. Synoptic evaluations confirmed that ultrafine model forecasts are better than the fine model forecasts.

Quirk, W. J.↗
NASA NTRS1981

High-resolution passive microwave imaging of the surface of the Earth

The physics of passive microwave observations of the Earth and the system requirements for high-resolution imaging within this spectral band are summarized. High resolution is achieved in a straightforward manner by increasing the size of the primary antenna. However, with a single receiver, it is shown that the combination of high resolution and crosstrack scanning cannot produce images which have valuable geophysical content. The concept of a multiple receiver array located in the focal plane is presented as the only practical solution to the dilemma. Exploring this concept, system requirements are generated which, for the first order, appear to offer solutions to the problem.

Swift, C. T.↗
NASA NTRS1982

Ultra high resolution molecular beam cars spectroscopy with application to planetary atmospheric molecules

The measurement of high resolution pulsed and continuous wave (CW) coherent anti-Stokes Raman spectroscopy (CARS) measurements in pulsed and steady state supersonic expansions were demonstrated. Pulsed molecular beam sources were characterized, and saturation of a Raman transition and, for the first time, the Raman spectrum of a complex molecular cluster were observed. The observation of CW CARS spectra in a molecular expansion and the effects of transit time broadening is described. Supersonic expansion is established as a viable technique for high resolution Raman spectroscopy of cold molecules with resolutions of 100 MH2.

Byer, R. L.↗
NASA NTRS1981

High-resolution radio observations of G82.6+0.4

The region of AFGL 2636, a multicomponent infrared source from which the unidentified 3.3 micron emission feature is observed, has been mapped at 20 cm with a resolution of 1.5 arcsec, at 9 cm at a resolution of 4.6 arcmin, and at 6 cm with a resolution of 0.5 arcsec. It is found that the large-scale distribution of the ionized gas and the extent of the heated dust are well correlated. An upper limit of 3 kpc is placed on the distance to this region. Nine-cm observations of AFGL 437 and AFGL 3053, which also exhibit the 3.3 micron feature, are also discussed.

Rossano, G. S.↗
NASA NTRS1981

High-resolution ultraviolet solar observations from sounding rockets and Spacelab

High spatial (about 1 arcsec) and temporal (20 sec) resolution UV solar spectroscopy has been carried out by the Naval Research Laboratory from sounding rockets since 1975. The High Resolution Telescope and Spectrograph payload, consisting of a 300 mm diameter x 4500 mm focal length Cassegrain telescope and the tandem Woodsworth spectrograph, was used to make the observations. Using this instrument, a multitude of highly energetic phenomena can be observed in the chromosphere, transition zone, and corona. High-resolution photographs of the UV continuum at 1600 A, used to study the fine structure and evolution of the temperature minimum layer, show that because of its strong spatial and temporal intensity fluctuations, the 1600 A continuum emission comes from not only the temperature minimum, but a variety of temperature regimes. Similar spatial and temporal behavior is seen in lower chromospheric lines of Si I. Typical line profiles of the C IV 1550 A line illustrate the fine structure and dynamics of the transition zone; the mass and energy flux balance in this zone is also determined.

Brueckner, G. E.↗
NASA NTRS1982

16 November 1979 gamma-ray bursts observed with HEAO-3 High-Resolution Gamma-Ray Spectrometer

On 1979 November 16, two gamma-ray bursts were observed by the High-Resolution Gamma-Ray Spectrometer on HEAO-3. The first event occurred at 14:16:41 U.T. and lasted about eight seconds. This event was detected only by the instrument's five CsI anticoincidence shield pieces. The second event occurred 61 sec later, at 14:17:42, and lasted about 18 sec. This event was clearly detected by the high-resolution germanium detectors. Because of the close temporal coincidence of the two events, the possibility is considered that both events originated from one celestial source, and that the scanning motion of HEAO-3 (nominal spin period 20 min) excluded the first from the approximately 30 deg FWHM field of view of the germanium detectors but included the second. Directional information from the relative response of the five shield pieces and the earth occultation constraint are all consistent with this interpretation and suggest a source location near RA equals 10 hr, Dec equals 45 deg. No significant spectral features appear in the high-resolution data from the second burst.

Wheaton, W. A.↗
NASA NTRS1982

High-resolution dayglow O I /1304 A/ and O I /989 A/ rocket observations

High-resolution (about 1 A) dayglow observations of the O I(1304) A) and O I(989 A) multiplets were made from an Astrobee-F rocket payload (25.046 CE) launched from White Sands, New Mexico at local noon on June 27, 1980 to an apogee of 260 km. Three components of the O I(1304 A) multiplet were measured at zenith angles of approximately 50 and 140 deg at 1.1 A resolution. Over the entire altitude range of observation, i.e., 100-260 km, the three components were found to be equal to within + or - 15%. The shape of the O I(989 A) multiplet distribution observed on the flight at 1.3 A resolution was indistinguishable from an optically thin source with the energy levels of the excited state populated according to their statistical weights in spite of the large optical depths of the O I(989 A) multiplet at rocket altitudes.

Christensen, A. B.↗
NASA NTRS1982

Assessment of radar resolution requirements for soil moisture estimation from simulated satellite imagery

Radar simulations were performed at five-day intervals over a twenty-day period and used to estimate soil moisture from a generalized algorithm requiring only received power and the mean elevation of a test site near Lawrence, Kansas. The results demonstrate that the soil moisture of about 90% of the 20-m by 20-m pixel elements can be predicted with an accuracy of + or - 20% of field capacity within relatively flat agricultural portions of the test site. Radar resolutions of 93 m by 100 m with 23 looks or coarser gave the best results, largely because of the effects of signal fading. For the distribution of land cover categories, soils, and elevation in the test site, very coarse radar resolutions of 1 km by 1 km and 2.6 km by 3.1 km gave the best results for wet moisture conditions while a finer resolution of 93 m by 100 m was found to yield superior results for dry to moist soil conditions.

Ulaby, F. T.↗