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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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NASA NTRS1981

Astronomical imaging investigations for Shuttle and Spacelab missions

General objectives of space astronomical imagery are briefly examined, taking into account the improved angular resolution achievable in space observations, the utilization of an accessibility of the far ultraviolet spectral range for an easier detection and more accurate measurement of very hot stars, the determination of the structure and evolution of galaxies, and the determination of the cosmic distance scale. Attention is given to the Ultraviolet Imaging Telescope, the Spacelab Wide Angle Telescope, and the Starlab UV/optical telescope facility. It is pointed out that Starlab is envisioned as a multi-instrument, multi-purpose astronomical facility based on a near-diffraction-limited Ritchey-Chretien telescope of about 1 meter aperture and f/15 focal ratio. These resolutions are a factor of 10 better than typically achieved with ground-based telescopes.

Carruthers, G. R.↗
NASA NTRS1981

Far-ultraviolet diffuse galactic light

Diffuse galactic light is detected at very low galactic latitudes, and useful upper limits are obtained at moderate and high galactic latitudes. Together, these data indicate that the albedo of the interstellar grains is high (a greater than 0.5) and that the grains very strongly (g greater than 0.7) forward-scatter far-ultraviolet radiation.

Henry, R. C.↗
NASA NTRS1993

Extreme Ultraviolet Explorer deep survey observations of a large flare on AU Microscopii

We have made the first extended observation of a stellar flare in the EUV with 100 s time resolution. The flare was detected on AU Mic by the Extreme Ultraviolet Explorer satellite at 12:38 UT on 1992 July 15 during a 4 d observation from 1992 July 14 to 18. This was a large flare detected in the Lexan/boron (65-190 A) band with an observed peak count rate of 7.0 +/- 0.5 counts/s, corresponding to a peak luminosity of 10 exp 30 erg/s in the Lexan/boron bandpass. This is significantly above the measured quiescent level of 0.4 +/- 0.2 counts/s. The flare consisted of a sharp peak lasting about 2 hr, followed by a decaying tail that lasted more than a day. The total EUV energy of the event is estimated to be 3 x 10 exp 34 ergs. A second, smaller flare was also observed and is described. We conclude that the large emission measures on order of 6 x 10 exp 53/cu cm are due to large volumes with characteristic length scales of order the stellar radius. We compare these EUV observations with stellar flare observations in other bandpasses and estimate the likelihood of seeing similar flares in future observations.

Cully, Scott L.↗
NASA NTRS2007

UVOT Detection of GRB Afterglows

The automated response of the UltraViolet and Optical Telescope (UVOT) on Swift to new GRBs has remained stable since March 15,2006. From then through August 10, 2007, UVOT observed 122 of the 129 GRBs detected with Swift's Burst Alert Telescope (BAT). UVOT typically takes an initial 100-s exposure with the White filter (160-650 nm) starting 60 - 180 s after the trigger followed by exposures with the other 6 filters. UVOT detected 37% of the 79 long GRBs (T90 > 2.0 s) that had modest reddening in the Milky Way (E(B-V) < 0.5) and were observed within 180 seconds of the trigger. Magnitudes ranged from 12.8 to the sensitivity limit of approx.21. Only 1 of 8 short GRBs were detected, and its magnitude was near the sensitivity limit. We also report correlations of afterglow magnitudes with other GRB properties.

Marshall, Frank↗
NASA NTRS1988

Ultraviolet Lidar Would Measure Wind Velocity

Incoherent Doppler-shifted scattering from aerosols reveals important weather data. Remote-sensing system in early stage of development makes global measurements of wind velocities along probing beam of ultraviolet light. In aviation system promotes safety through detection of wind shears and clear-air turbulence. System includes range-gated ultraviolet-excimer laser operating at 308 or 353 nm.

Mcdermid, Iain Stuart↗
NASA NTRS1986

IUE spectra of flares on AU Mic

Some IUE spectra were obtained in August 1980 through a substantial part of the optical cycle of the BY Draconis-type, spotted M dwarf star, AU Mic. No modulation of the ultraviolet emission line fluxes in antiphase with the optical curve is detected. Simultaneous optical photometry of AU Mic shows remarkably poor correlation of optical flare strength and ultraviolet emission-line enhancements. The flares detected on AU Mic show considerable variety in the degree of enhancement in the various emission lines and optical continuum.

Butler, C. J.↗
NASA NTRS2009

Use of UV Sources for Detection and Identification of Explosives

Measurement of Raman and native fluorescence emission using ultraviolet (UV) sources (<400 nm) on targeted materials is suitable for both sensitive detection and accurate identification of explosive materials. When the UV emission data are analyzed using a combination of Principal Component Analysis (PCA) and cluster analysis, chemicals and biological samples can be differentiated based on the geometric arrangement of molecules, the number of repeating aromatic rings, associated functional groups (nitrogen, sulfur, hydroxyl, and methyl), microbial life cycles (spores vs. vegetative cells), and the number of conjugated bonds. Explosive materials can be separated from one another as well as from a range of possible background materials, which includes microbes, car doors, motor oil, and fingerprints on car doors, etc. Many explosives are comprised of similar atomic constituents found in potential background samples such as fingerprint oils/skin, motor oil, and soil. This technique is sensitive to chemical bonds between the elements that lead to the discriminating separability between backgrounds and explosive materials.

Hug, William↗
NASA NTRS1989

Ozone/Ultraviolet-Photo-Oxidation Reactor

Experimental chemical-processing system destroys waste hydrazine in water by use of ozone in ultraviolet-photo-oxidation reactor. New process reduces concentrations of hydrazines and intermediate decomposition products in effluent liquid and gas to below limit of detectability. Liquid sprayed in reaction chamber past ultraviolet lamps, against flow of oxygen and ozone. Hydrazines and intermediate decomposition products oxidized to harmless substances. Effectiveness and speed of process depends on maintenance of circulating liquid at correct pH, determines lower limit of oxidation by ozone.

Swartz, Ari Ben↗
NASA NTRS2010

NASA Tech Briefs, April 2010

Topics covered include: Active and Passive Hybrid Sensor; Quick-Response Thermal Actuator for Use as a Heat Switch; System for Hydrogen Sensing; Method for Detecting Perlite Compaction in Large Cryogenic Tanks; Using Thin-Film Thermometers as Heaters in Thermal Control Applications; Directional Spherical Cherenkov Detector; AlGaN Ultraviolet Detectors for Dual-Band UV Detection; K-Band Traveling-Wave Tube Amplifier; Simplified Load-Following Control for a Fuel Cell System; Modified Phase-meter for a Heterodyne Laser Interferometer; Loosely Coupled GPS-Aided Inertial Navigation System for Range Safety; Sideband-Separating, Millimeter-Wave Heterodyne Receiver; Coaxial Propellant Injectors With Faceplate Annulus Control; Adaptable Diffraction Gratings With Wavefront Transformation; Optimizing a Laser Process for Making Carbon Nanotubes; Thermogravimetric Analysis of Single-Wall Carbon Nanotubes; Robotic Arm Comprising Two Bending Segments; Magnetostrictive Brake; Low-Friction, Low-Profile, High-Moment Two-Axis Joint; Foil Gas Thrust Bearings for High-Speed Turbomachinery; Miniature Multi-Axis Mechanism for Hand Controllers; Digitally Enhanced Heterodyne Interferometry; Focusing Light Beams To Improve Atomic-Vapor Optical Buffers; Landmark Detection in Orbital Images Using Salience Histograms; Efficient Bit-to-Symbol Likelihood Mappings; Capacity Maximizing Constellations; Natural-Language Parser for PBEM; Policy Process Editor for P(sup 3)BM Software; A Quality System Database; Trajectory Optimization: OTIS 4; and Computer Software Configuration Item-Specific Flight Software Image Transfer Script Generator.

Source record↗
NASA NTRS1999

A Complete Sample of Hot Post-AGB Stars in Globular Clusters

Ultraviolet images of globular clusters are often dominated by one or two "UV-bright" stars. The most luminous of these are believed to be post-AGB stars, which go through a luminous UV-bright phase as they leave the AGB and move rapidly across the HR diagram toward their final white dwarf state. During the two flights of the ASTRO observatory in 1990 and 1995, the Ultraviolet Imaging Telescope (UIT, Stecher 1997, PASP, 109, 584) was used to obtained ultraviolet (1600 A) images of 14 globular clusters. These images provide a complete census of hot (> 8000 K) post-AGB stars in the observed globular clusters, because the 40' field of view of UIT is large enough to image the entire population of most Galactic globulars, and because the dominant cool star population is suppressed in ultraviolet images, allowing UV-bright stars to be detected into the cluster core. We have begun a program of optical and STIS ultraviolet spectroscopy to determine the fundamental stellar parameters (\log L, T_eff, \log g) of all the hot post-AGB candidates discovered on the UIT images. Among the goals of our program are to test theoretical post-AGB lifetimes across the HR diagram, and to estimate the mass of the currently forming white dwarfs in globular clusters. Two trends are already apparent in our survey. First, the UV-selected sample has removed a bias against the detection of the hottest post-AGB stars, and resulted in the discovery of five cluster post-AGB stars with Teff > 50,000 K. Second, most of the new discoveries have been lower luminosity (2.5 $<$\log L $<$ 3.0) than expected for stars which leave the AGB during the thermally pulsating phase.

Landsman, W.↗
NASA NTRS1994

The early bolometric evolution of Nova Cygni 1992

We report on combined ultraviolet and optical observations of early stages of the outburst of Nova Cygni 1992. We show that the initial optical rise and decline were produced by the dramatic increase in UV line opacity and its gradual subsequent lifting as the ejecta expand. The source of the M(sub v) - t(sub 3) relation is easily understood in light of these low-resolution UV spectra. The multiwavelength data confirm the theoretical prediction that a nova evolves at a constant bolometric luminosity in the early stages of outburst. We verify the prediction for this nova for at least the first month of the outburst. The detection of far-UV radiation with the Voyager Ultraviolet Spectrometer and the detection of an increasing X-ray flux with Roentgen Satellite (ROSAT) imply that this phase lasted for more than 6 months.

Shore, Steven N.↗
NASA NTRS1971

The application of an ultraviolet sensitive fire detector in a manned space vehicle.

Description of a detector which is sensitive to the ultraviolet molecular emissions of flames and has been selected as the basic element of the NASA Skylab fire-detection system. This detector is sensitive to approximately 10 to the minus 12th watts of ultraviolet radiation and will detect small flames at distances in excess of three meters. Its response to a variety of burning spacecraft materials has been investigated both in one-gravity and zero-gravity. The results of experiments conducted in an aircraft flying zero-gravity parabolas in an attempt to simulate the characteristics of a fire which the detector must sense are cited.

Linford, R. M. F.↗
NASA NTRS2017

Spectroscopic Chemical Analysis Methods and Apparatus

Spectroscopic chemical analysis methods and apparatus are disclosed which employ deep ultraviolet (e.g. in the 200 nm to 300 nm spectral range) electron beam pumped wide bandgap semiconductor lasers, incoherent wide bandgap semiconductor light emitting devices, and hollow cathode metal ion lasers to perform non-contact, non-invasive detection of unknown chemical analytes. These deep ultraviolet sources enable dramatic size, weight and power consumption reductions of chemical analysis instruments. In some embodiments, Raman spectroscopic detection methods and apparatus use ultra-narrow-band angle tuning filters, acousto-optic tuning filters, and temperature tuned filters to enable ultra-miniature analyzers for chemical identification. In some embodiments Raman analysis is conducted along with photoluminescence spectroscopy (i.e. fluorescence and/or phosphorescence spectroscopy) to provide high levels of sensitivity and specificity in the same instrument.

Hug, William F.↗
NASA NTRS2018

Spectroscopic Chemical Analysis Methods and Apparatus

Spectroscopic chemical analysis methods and apparatus are disclosed which employ deep ultraviolet (e.g. in the 200 nm to 300 nm spectral range) electron beam pumped wide bandgap semiconductor lasers, incoherent wide bandgap semiconductor light emitting devices, and hollow cathode metal ion lasers to perform non-contact, non-invasive detection of unknown chemical analytes. These deep ultraviolet sources enable dramatic size, weight and power consumption reductions of chemical analysis instruments. In some embodiments, Raman spectroscopic detection methods and apparatus use ultra-narrow-band angle tuning filters, acousto-optic tuning filters, and temperature tuned filters to enable ultra-miniature analyzers for chemical identification. In some embodiments Raman analysis is conducted along with photoluminescence spectroscopy (i.e. fluorescence and/or phosphorescence spectroscopy) to provide high levels of sensitivity and specificity in the same instrument.

Hug, William F.↗
NASA NTRS1992

Remote Detection of Biological Particles and Chemical Plumes Using UV Fluorescence Lidar

A lidar system based on ultraviolet (UV) laser induced fluorescence (LIF) was developed for the remote detection of atmospherically dispersed biological particles and chemical vapors. This UV fluorescence lidar has many potential applications for monitoring environmental pollution, industrial waste emission, agricultural insect control, illicit chemical processing, and military defense operations. The general goal of this work is to investigate the research issues associated with the long range detection and identification of chemicals, e.g. aromatic solvents and chemical precursors, and biological materials, e.g. bacillus thuringiensis (BT) and bacillus globiggi (BG). In the detection of biological particulates, we are particularly interested in extending the detection range of an existing solar-blind 248-nm lidar system. We are investigating the use of longer excitation laser wavelengths (i.e. lambda greater than 280-nm to have more favorable atmospheric light transmission characteristics) for improving detection range to better than 10 km. In the detection of chemical plumes, our main research objectives are to determine how accurately and sensitively a chemical plume can be located at range, and how well spectrally the chemical species can be measured to allow their identification.

J J Tiee↗
NASA NTRS1975

Mariner 9 observations of beta Cephei stars

Ultraviolet spectra of three beta Cep variables and a nonvariable star of similar spectral type were observed by the ultraviolet spectrometer on Mariner 9. A significant light variation at 1400 A may have been detected for beta Cep. The variable stars have mean ultraviolet spectra similar to that of the nonvariable star and do not show any significant short-period spectral variations.

Lesh, J. R.↗
NASA NTRS1986

Highly ionized atoms in cooling gas

The ionization of low density gas cooling from a high temperature was calculated. The evolution during the cooling is assumed to be isochoric, isobaric, or a combination of these cases. The calculations are used to predict the column densities and ultraviolet line luminosities of highly ionized atoms in cooling gas. In a model for cooling of a hot galactic corona, it is shown that the observed value of N(N V) can be produced in the cooling gas, while the predicted value of N(Si IV) falls short of the observed value by a factor of about 5. The same model predicts fluxes of ultraviolet emission lines that are a factor of 10 lower than the claimed detections of Feldman, Brune, and Henry. Predictions are made for ultraviolet lines in cooling flows in early-type galaxies and clusters of galaxies. It is shown that the column densities of interest vary over a fairly narrow range, while the emission line luminosities are simply proportional to the mass inflow rate.

Edgar, R. J.↗