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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 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Infrared spectra of molecules and materials of astrophysical interest

The vibrational spectra from 4000 to 33 cm-1 of several modecules which may be present in the atmosphere of the Jovian planets are studied to provide vibrational frequencies which can be used to: (1) determine the composition of the cloud covers of several of the planets; (2) provide structural information under favorable circumstances; (3) provide necessary data from which accurate thermodynamic data can be calculated; and (4) furnish information as to the nature of the potential energy function of the molecules and forces acting within them. Some of the molecules are produced photochemically from methane, ammonia, and hydrogen sulfide which are thought to be constituents of the planets with reducing atmospheres. Some of the compounds polymerize under ultraviolet radiation and drop out of the atmospheres. However, planets with a hot base, like that of Jupiter, may rebuild molecules destroyed photochemically.

Durig, J. R.↗
NASA NTRS1976

Infrared spectra of molecules and materials of astrophysical interest

The vibrational spectra from 4,000 to 33/cm of several molecules which may be present in the atmosphere of the Jovian planets or exist in outer space were studied. These studies have been made to provide vibrational frequencies which can be used to: (1) determine the composition of the cloud covers of several of the planets, (2) provide structural information under favorable circumstances, (3) provide necessary data from which accurate thermodynamic data can be calculated, and (4) furnish information as to the nature of the potential energy function of the molecules and forces acting within them. Some of the molecules studied can be produced photochemically from methane, ammonia, and hydrogen sulfide which are thought to be constituents of the planets with reducing atmospheres. Some of the compounds will polymerize under ultraviolet radiation and drop out of the atmospheres. However, planets with a hot base, like that of Jupiter, may rebuild molecules destroyed photochemically. These criteria were used in selecting the compounds under study.

Durig, J. R.↗
NASA NTRS1976

Feasibility of using S-191 infrared spectra for geological studies from space

Use of the S-191 spectrometer system aboard the SKYLAB(SL3) mission shows that geologically meaningful spectra can be extracted from the data by which terrain target can be differentiated. The Si-O bond in all silicates (which form most surface rocks) produced an emission minimum which is characteristic of a mineral, or a set of minerals, in a rock. The underflight RB57 mission was far more successful, primarily because of its much slower velocity allowing a higher signal/noise, and hence better spectral resolution for any given area terrain. With the RB57 spectra, areas can be differentiated and significant differences in rock targets demonstrated. The geological provenance of some alluvial outwash in the nearby mountains over which the aircraft also flew its flight strip can be indicated.

Lyon, R. J. P.↗
NASA NTRS1978

Infrared spectra of lunar soils

Lunar sample measurements were made both under ambient nitrogen pressure and under vacuum conditions. Average emittance values were analyzed for a number of samples which were determined to include silicate minerals, pyroxenes, and fine particle feldspar. Information is also provided on modifications made to emittance apparatus in order to work with smaller sample sizes and to prevent accidental loss or contamination of the lunar sample material.

Aronson, J. R.↗
NASA NTRS1978

Upconversion of broadband infrared spectra

An experimental device successfully upconverts IR radiation in the 3.2-5.0 micron wavelength range simultaneously to visible light at 0.80-0.88 microns, while preserving frequency coding and is thus applicable to IR spectroscopy. The 1.8-micron bandwidth of IR radiation that is upconverted without temperature or phase match tuning is the largest yet reported. The over-all system quantum efficiency of the upconverter/spectrometer system is 0.01% and could be improved to 0.4%.

Gurski, T. R.↗
NASA NTRS1979

Investigation of infrared spectra of atmospheric gases to support stratospheric spectroscopic investigations

Four papers are presented which discuss the following: information measures in nonlinear experimental design; information in spectra of collision broadened absorption lines; band analysis by spectral curve fitting; and least squares analysis of Voight shaped lines. Abstracts of five research papers on which the author collaborated and which were delivered at the 34th Symposium of Molecular Spectroscopy (Ohio State University, June 1979) are included along with a subroutine for use with BMDP3R to retrieve the parameters of 10 Voight shaped lines.

Shaw, J. H.↗
NASA NTRS1978

Near-infrared spectra of the Galilean satellites - Observations and compositional implications

Reflectivity spectra of the trailing and leading sides of Io, Europa, Callisto, and Ganymede are analyzed which were obtained at an altitude of 41,000 ft from the Kuiper Airborne Observatory with circular variable filter-wheel spectrometers in the spectral region from 0.7 to 5.5 microns. The data are compared with laboratory spectrum and with synthetic spectra constructed on the basis of simple multiscattering theory. The 2.9-micron feature in Callisto's spectra is attributed primarily to bound water; the fractional amounts of water-ice cover on the trailing and leading sides of Ganymede and on the leading side of Europa are estimated. The bare-ground areas on Ganymede are shown to have reflectivity properties comparable to those of Callisto's surface in the studied spectral region, and the surfaces of both satellites are found to contain significant quantities of bound water. It is suggested that minor but significant amounts of ferrous-bearing material (either ferrous salts or alkali feldspars) can account for the 1.35-micron feature of Io.

Pollack, J. B.↗
NASA NTRS1980

Investigation of infrared spectra of atmospheric gases to support stratospheric spectroscopic investigations

Spectroscopic instrumentation and the absorption characteristics of atmospheric gases are discussed in relation to the requirements of spectroscopic stratospheric experiments. Improvement in the spectral resolution, accuracy of the line parameters, and the ranges of atmospheric conditions over which information is to be obtained are among the factors considered. Methods of simultaneously analyzing entire bands containing many lines were developed and applied to the analysis of bands of N20 and CO2. Progress in this analysis is reported.

Shaw, J. H.↗
NASA NTRS1979

The infrared spectra of Uranus, Neptune, and Titan from 0.8 to 2.5 microns

The paper combines the results of two projects that significantly augment previous studies: exploratory IR spectroscopic observations of Uranus, Neptune, and Titan using a 4-m telescope; and new long-path laboratory comparison spectra of methane at abundances appropriate for these planetary spectra. The observations of these previously unexplored spectral regimes provide new insights into the composition and structures of these atmospheres. The spectra of Uranus, Neptune, and Titan are discussed and analyzed from several complementary points of view. A number of specific topics are discussed in detail: methane abundance determinations, limitations in using the 3nu3 CH4 band at high abundances, upper limits to a number of molecules, implications from the pressure-induced spectrum of H2, and consequences of Rayleigh scattering in Uranus's upper atmosphere.

Fink, U.↗
NASA NTRS1979

Infrared spectra of IC 418 and NGC 6572

Spectrophotometric observations from 2 to 4 and 8 to 13 microns of NGC 6572 and from 4 to 13 microns of IC 418 are reported. Also reported are observations of the size of IC 418 in the optical and at 1.65 and 2.2 microns. Both planetary nebulae emit more radiation than expected from recombination at wavelengths longer than -4 microns; this radiation is attributed to heated dust. The spectra show a plateau from 10.5 to 13 microns, and this peak is tentatively attributed to emission from large silicon carbide particles. Fine-structure emission lines are also discussed; the presence of (forbidden Ar III) but not (forbidden Ne II) in NGC 6572 suggests that ions having the same ionization potential can nevertheless have different fractional abundances.

Willner, S. P.↗
NASA NTRS1980

Low resolution infrared spectra of quasars

Recent observational results based on a joint infrared/optical survey of the hydrogen line spectra of a significant number of low and high redshift quasars are summarized. The spectra show that the Paschen-alpha and Balmer line ratios do not agree with the result of nominal case B recombination theory and vary widely within the quasars sampled. The range of P-alpha to H-beta ratios is a factor of roughly 6, while the range in Ly-alpha to H-alpha ratios is a factor of roughly 5. For the P-alpha:Balmer series, the deviations from case B recombination are not consistent with reddening, but appear, within large dispersions, to be consistent with optical depth effects in the Balmer lines affecting the lines ratios.

Soifer, B. T.↗
NASA NTRS1981

Mars - Far-infrared spectra and thermal-emission models

Spectra of Mars from 100 to 360 kaysers were obtained during three different observation periods from NASA's Kuiper Airborne Observatory. Also, a new thermal model was constructed for the surface of Mars, and synthetic spectra were computed from the models to compare with the observations. The models include the effects of a dusty atmosphere which absorbs, scatters, and reradiates energy. The synthetic spectra show significant effects on disk-averaged brightness temperatures, as well as absorption features due to silicate dust. The spectra of Mars, which are ratios of Mars to the moon, do not fit the synthetic spectra unless the surface emissivities of Mars and the moon have different dependencies on wavelength. A possible explanation for this behavior is a difference in soil particle-size distributions between Mars and the moon, with Mars being depleted in large particles compared to the moon. Small particles are consistent with clay minerals which have been suggested elsewhere as constituents of the Martian surface.

Simpson, J. P.↗
NASA NTRS1982

Observations of silicate reststrahlen bands in lunar infrared spectra

Thermal emission spectra of three lunar sites (Apollo 11, Descartes Formation, and Tycho central peak) are measured in the 8-14 micron spectral range. Transmission and instrument effects are accounted for by forming ratios of the Descartes and Tycho spectra to the Apollo 11 spectrum. The ratio spectra are compared with ratios of published laboratory spectra of returned lunar samples and also with ratio spectra calculated using the Aronson-Emslie (1975) model. The comparisons show pyroxene bands in the Descartes ratio spectrum and plagioclase bands in the Tycho ratio spectrum. The Tycho spectrum is found to be consistent with the existence of fine plagioclase dust (approximately 1 micron) at the rock surface and a higher-than-usual sodium content of the plagioclase.

Potter, A. E., Jr.↗
NASA NTRS1982

Infrared spectra of galactic center sources

Absorption due to CO and emission from atomic hydrogen and neutral helium observed in high resolution 2-micron spectra of five compact sources in the central parsec of the galaxy furnish information concerning the condition, distribution and kinematics of red giant stars and ionized gas in the galactic core. It is found that all three red giant sources observed are blueshifted, and that there are no detectable absorptions in the continuum of the central source IRS 16.

Wollman, E. R.↗