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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 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
NASA NTRS1987

Colorless Polyimide Films for Thermal-Control Coatings

Series of six essentially colorless aromatic polyimide films synthesized and characterized with objective of obtaining maximum optical transparency for applications in space; optical transparency requirement for high-performance polymeric films used in second-surface mirror coatings on thermal-control systems. Films remain more transparent than commercial film after ultraviolet and electron irradiation. Increased transparency and enhanced solubility of optically transparent polyimides makes them viable candidates for use in thermal-control coatings.

St. Clair, Anne K.↗
NASA NTRS1987

Effects of Monatomic Oxygen on Coatings

Report describes tests in which paints, metals, and optical materials carried in orbit around Earth determined how monatomic oxygen in rare orbital atmosphere affects them. Specimen disks carried aloft on Space Shuttle and exposed for 41.17 h at altitude of 120 nmi (222 km).

Whitaker, Ann↗
NASA NTRS1987

Processable Polyimides Containing ATBN Elastomers

Void-free moldings obtained without serious sacrifice in other properties. New synthesis produces high-temperture linear aromatic polyimide processed in imide form to yield tough, void-free components without serious sacrifice in other properties. Linear aromatic condensation polyimides are materials of prime choice for use as adhesives, composite matrix resins, films, coatings, and/or moldings where durability at temperatures as high as 200 to 300oC needed. Finding increasing use in aircraft and spacecraft applications.

St. Clair, Anne K.↗
NASA NTRS1985

SSM atomic oxygen reactions on Kapton and silverized Teflon

Surface morphology studies using scanning electron microscopy on Kapton and Inconel silver coated Teflon material samples retrieved from the Solar Maximum Mission spacecraft revealed significant changes attributed to orbital atomic oxygen induced reactions. The Kapton recession observed on the aluminized Kapton material samples appeared equivalent in nature with that observed on previous Space Shuttle LEO missions. SSM Teflon taped material samples, coated on the back side with films of Inconel protected silver were observed degraded on both sides. Visibly severe reactions on the back side produced total blackening, generally restricted to areas of tape with a narrow direct view-factor of the external orbital environment. High magnification scanning electron microscope views provided evidence of near total silver reaction, flaking, and subsequent erosion of the underlying Teflon itself. Only three of the extensive S.E.M. photographs illustrating the basic reactions observed are included pending further detailed investigations.

Roger Linton↗
NASA NTRS1986

Soluble aromatic polyimides for film and coating applications

Linear all-aromatic polyimides have been synthesized and characterized which show much potential as films and coatings for electronic applications. Structure-property relations with regard to methods for obtaining solubility of fully imidized polymers will be discussed. Methods used to obtain solubility include variation of polymer molecular structure, variation of isomerism of the diamine monomer, modification of cure time/temperature and atmosphere. Other properties of soluble polyimides will be presented which include glass transition temperatures, thermooxidative stabilities, UV-visible spectra, and refractive indices.

St.clair, Anne K.↗
NASA NTRS1986

The TIMS Data User's Workshop

A workshop was held to bring together all users of data from NASA's airborne Thermal Infrared Multispectral Scanner (TIMS). The purpose was to allow users to compare results, data processing algorithms, and problems encountered; to update the users on the latest instrument changes and idiosyncracies, including distribution of the TIMS investigation guide; to inform the users of the wide range of problems that are currently being tackled by other TIMS investigators; to explore ways to expand the user community; to discuss current areas where more basic research is required; and to discuss the future directions of NASA's thermal infrared remote sensing programs. Also discussed were: geology, land use, archeology; and data processing and noise research.

Kahle, Anne B.↗
NASA NTRS1986

Calculation of day and night emittance values

In July 1983, the Thermal Infrared Multispectral Scanner (TIMS) was flown over Death Valley, California on both a midday and predawn flight within a two-day period. The availability of calibrated digital data permitted the calculation of day and night surface temperature and surface spectral emittance. Image processing of the data included panorama correction and calibration to radiance using the on-board black bodies and the measured spectral response of each channel. Scene-dependent isolated-point noise due to bit drops, was located by its relatively discontinuous values and replaced by the average of the surrounding data values. A method was developed in order to separate the spectral and temperature information contained in the TIMS data. Night and day data sets were processed. The TIMS is unique in allowing collection of both spectral emittance and thermal information in digital format with the same airborne scanner. For the first time it was possible to produce day and night emittance images of the same area, coregistered. These data add to an understanding of the physical basis for the discrimination of difference in surface materials afforded by TIMS.

Kahle, Anne B.↗
NASA NTRS1987

Fault-free performance validation of fault-tolerant multiprocessors

A validation methodology for testing the performance of fault-tolerant computer systems was developed and applied to the Fault-Tolerant Multiprocessor (FTMP) at NASA-Langley's AIRLAB facility. This methodology was claimed to be general enough to apply to any ultrareliable computer system. The goal of this research was to extend the validation methodology and to demonstrate the robustness of the validation methodology by its more extensive application to NASA's Fault-Tolerant Multiprocessor System (FTMP) and to the Software Implemented Fault-Tolerance (SIFT) Computer System. Furthermore, the performance of these two multiprocessors was compared by conducting similar experiments. An analysis of the results shows high level language instruction execution times for both SIFT and FTMP were consistent and predictable, with SIFT having greater throughput. At the operating system level, FTMP consumes 60% of the throughput for its real-time dispatcher and 5% on fault-handling tasks. In contrast, SIFT consumes 16% of its throughput for the dispatcher, but consumes 66% in fault-handling software overhead.

Czeck, Edward W.↗