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Thompson, W. R.

Publications and source records attributed to Thompson, W. R..

30 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1987

Solid hydrocarbon aerosols produced in simulated Uranian and Neptunian stratospheres

Solid hydrocarbon films were deposited in an RF plasma discharge of various CH4/H2/He mixtures under conditions simulating the formation of solid aerosols by magnetospheric charged particles in the stratospheres of Uranus and Neptune. The percentage of CH4 ranged from 0.0002 to 100 percent; the pressure in the discharge chamber was either 130 or 660 microbar; and the films produced were yellow to deep red-brown in color and 2-25 microns thick. The real and imaginary parts of the refractive index at wavelengths from 350 nm to 2.5 microns were determined for all the films, and the results are compared with observational data and the predictions of theoretical models in extensive tables and graphs. Good agreement is demonstrated, suggesting that aerosol production by this mechanism may be competitive with UV or charged-particle irradiation of hydrocarbon condensates.

Khare, B. N.↗
NASA NTRS1987

Chemical processes in Triton's atmosphere and surface

The Neptune moon Triton may have an appreciable atmosphere; the preliminary calculations of Delitsky (1983) have suggested that there should be a significant resultant chemistry in a possible N2 ocean with dissolved CH4, given charged-particle radiolysis of gaseous mixtures and gamma radiolysis of N2-CH4 solutions. The latter will yield substantial quantities of organic products which will be partially soluble in any N2-CH4 liquid present. Attention is presently given to the energy sources available for Triton, in order to estimate rates of synthesis and ascertain the possible history of such simple and complex organic products on Triton's surface.

Delitsky, M. L.↗
NASA NTRS1986

The organic aerosols of Titan

A dark reddish organic solid, called tholin, is synthesized from simulated Titanian atmospheres by irradiation with high energy electrons in a plasma discharge. The visible reflection spectrum of this tholin is found to be similar to that of high altitude aerosols responsible for the albedo and reddish color of Titan. The real (n) and imaginary (k) parts of the complex refractive index of thin films of Titan prepared by continuous dc discharge through a 0.9 N2/0.1 CH4 gas mixture at 0.2 mb is determined from X-ray to microwave frequencies. Values of n (approx. 1.65) and k (approx. 0.004 to 0.08) in the visible are consistent with deductions made by groundbased and spaceborne observations of Titan. Many infrared absorption features are present in k(lambda), including the 4.6 micrometer nitrile band. Molecular analysis of the volatile components of this tholin was performed by sequential and nonsequential pyrolytic gas chromatography/mass spectrometry. More than one hundred organic compounds are released; tentative identifications include saturated and unsaturated aliphatic hydrocarbons, substituted polycylic aromatics, nitriles, amines, pyrroles, pyrazines, pyridines, pyrimidines, and the purine, adenine. In addition,acid hydrolysis produces a racemic mixture of biological and nonbiological amino acids. Many of these molecules are implicated in the origin of life on Earth, suggesting Titan as a contemporary laboratory environment for prebiological organic chemistry on a planetary scale.

Khare, B. N.↗
NASA NTRS1985

Titan's organic chemistry

Voyager discovered nine simple organic molecules in the atmosphere of Titan. Complex organic solids, called tholins, produced by irradiation of the simulated Titanian atmosphere, are consistent with measured properties of Titan from ultraviolet to microwave frequencies and are the likely main constituents of the observed red aerosols. The tholins contain many of the organic building blocks central to life on earth. At least 100-m, and possibly kms thicknesses of complex organics have been produced on Titan during the age of the solar system, and may exist today as submarine deposits beneath an extensive ocean of simple hydrocarbons.

Sagan, C.↗
NASA NTRS1984

Titan - Far-infrared and microwave remote sensing of methane clouds and organic haze

Titan's surface and plausible atmospheric thermal opacity sources, which include gaseous N2, CH4, and H2, together with CH4 clouds and organic haze, are sufficient to match available earth-based and Voyager observations of Titan's thermal emission spectrum. Dominant thermal emission sources are the surface, at greater than 1 cm wavelengths, atmospheric N2 for the 1-200 micron range, condensed and gaseous CH4 for 200-20 microns, and molecular bands and organic haze at less than 20 microns.

Thompson, W. R.↗
NASA NTRS1984

Production and condensation of organic gases in the atmosphere of Titan

The rates and altitudes for the dissociation of atmospheric constituents on Titan are calculated for solar ultraviolet radiation, the solar wind, Saturn magnetospheric particles, the Saturn co-rotating plasma, and cosmic rays. Laboratory experiments show that a variety of simple gas phase organic molecules and more complex organic solids called tholins are produced by such irradiations of simulated Titanian atmospheres. Except for ultraviolet wavelengths longward of the methane photodissociation continuum, most dissociation events occur between about 3100 and 3600 km altitude, corresponding well to the region of EUV opacity detected by Voyager. For a wide variety of simple to moderately complex organic gases in the Titanian atmosphere, condensation occurs below the top of the main cloud deck at about 2825 km. It is proposed that such condensates, begining with CH4 at about 2615 km comprise the principal mass of the Titan clouds. There is a distinct tendency for the atmosphere of Titan to act as a fractional distillation device, molecules of greater complexity condensing out at higher altitudes.

Sagan, C.↗
NASA NTRS1984

The organic aerosols of Titan

The optical properties and chemical composition of thiolin, an organic solid synthesized by high-energy-electron irradiation in a plasma discharge (Sagan et al., 1984) to simulate the high-altitude aerosols of Titan, are investigated experimentally using monochromators, ellipsometers, and spectrometers (on thin films deposited by continuous dc discharge) and sequential and nonsequential pyrolytic gas chromatography/mass spectrometry (of the volatile component), respectively. The results are presented in tables and graphs and characterized. The real and imaginary elements of the complex refractive index in the visible are estimated as 1.65 and 0.004-0.08, respectively, in agreement with observations of Titan, and the IR absorption features include the nitrile band at 4.6 microns. The molecules identified in the volatile part of thiolin include complex species considered important in theoretical models of the origin of life on earth.

Khare, B. N.↗
NASA NTRS1982

Production and condensation of organic gases in the atmosphere of Titan

The rates and altitudes for the dissociation of atmospheric constituents on Titan are calculated for solar ultraviolet radiation, the solar wind, Saturn magnetospheric particles, the Saturn co-rotating plasma, and cosmic rays. Laboratory experiments show that a variety of simple gas phase organic molecules and more complex organic solids called tholins are produced by such irradiations of simulated Titanian atmospheres. Except for ultraviolet wavelengths longward of the methane photodissociation continuum, most dissociation events occur between about 3100 and 3600 km altitude, corresponding well to the region of EUV opacity detected by Voyager. For a wide variety of simple to moderately complex organic gases in the Titanian atmosphere, condensation occurs below the top of the main cloud deck at about 2825 km. It is proposed that such condensates, beginning with CH4 at about 2615 km, comprise the principal mass of the Titan clouds. There is a distinct tendency for the atmosphere of Titan to act as a fractional distillation device, molecules of greater complexity condensing out at higher altitudes.

Sagan, C.↗
NASA NTRS1972

Rocket nozzle coolant channel thermal analysis program (E25107)

A complete description of the liquid cooled rocket nozzle analysis program (E25107) is presented, including a users manual, program listing, and a sample problem. The program is recommended for use in designing liquid cooled rocket nozzles. In addition, it is adaptable to any system in which a liquid-cooled tubular structure is used to contain and direct the flow of a hot gas.

Thompson, W. R.↗