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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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Time controllable continuous photon emission from plasma produced by pulsed laser vacuum spark applied to absorption spectroscopy in vacuum UV
An experimental program is being developed to obtain measurements of the incident surface radiation in the 1000 A to 2000 A range from the shock stagnation region of a blunt model in the Ames 20 MW Arc-Jet Wind Tunnel. The setup consists of a water-cooled blunt model, with a magnesium fluoride forward-viewing window. Radiation incident on the window is optically imaged via an evacuated system and reflective optical elements onto the entrance slit of a spectrograph. The model will be exposed to the supersonic plasma stream from the exit nozzle of the arc-jet tunnel. The resulting bow shock radiation will be measured. It is expected that this experiment will help evaluate the importance of atomic N and O lines to the radiative heating of future Aeroassist Space Transfer Vehicles (ASTVs).
Vacuum spectroscopy of Lyman-Birge-Hopfield nitrogen system and fourth positive system of carbon-oxide for improved ultraviolet measurement techniques
Vacuum ultraviolet detector evaluation - spectroscopy systems for capsule reentry measurements
Vacuum ultraviolet spectroscopy in planetary atmosphere studies
Absorption coefficients of molecular oxygen at Lyman alpha line and vicinity measured by vacuum spectroscopy
Vacuum ultraviolet detector-spectroscopy systems for capsule reentry measurements
For a complete study of the photoionization of atoms and molecules it is essential to make use of the technique of Photoelectron Spectroscopy and the continuum characteristics of synchrotron radiation. A brief review is given of the application of the above techniques in measuring partial photoionization cross sections and the angular distribution assymetry parameter beta. Selected results are given, which are compared to theoretical values.
Carbonate grains in carbonaceous chondrites record aqueous alteration events on the asteroidal parent bodies, including evidence for episodic alteration, timing of alteration, and time and temperature evolution of volatiles. Spectral features in the 3.4 μm region at asteroid Bennu have been interpreted as coming from carbonate minerals. Coordinated analysis of carbonate grains will be a valuable tool for analysis of Bennu samples, and related analysis of analog materials provides important context for understanding aqueous alteration of carbonaceous asteroids more broadly. To that end, our team is analyzing carbonates in Bennu analog materials, using Raman spectroscopy to identify carbonates and assess the maturity of related organic materials, vacuum reflectance spectroscopy from the ultraviolet through thermal infrared range to constrain contributions from carbonates and organics, X-ray microtomography and electron probe microanalysis (EPMA) to assess the distribution of void space, transmission electron microscopy to characterize space weathering effects, and EPMA and secondary ion mass spectrometry (SIMS) to measure composition and isotopic ratios. Here, we describe in situ analysis of carbon and oxygen isotopes from carbonates in Grosvenor Mountains (GRO) 95577.
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Vacuum UV instrumentation for optical studies of solids
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Rotatable vacuum spectrograph and solar spectroheliograph with plane grating and two mirrors at Manila Observatory
Uranium-containing materials, refractory metals and alloys, discussing interface interaction, thermionic properties and parameters of vacuum electron emission stability
Large vacuum facility tests of MPD arc thrustor
High resolution vacuum spectrograph region between 1000 and 2000 angstroms
Vacuum UV spectrum of neutral silicon, presenting wavelength measurements, relative intensities of Ge lines and Ritz standards
Large vacuum facility tests of MPD arc thrustor