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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 163 records · Page 9

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NASA NTRS1972

Apollo window meteoroid experiment

The Apollo window meteoroid experiment is described which uses the Apollo command module heat shield window surfaces to obtain information about the flux of meteoroids with masses of 10 to the minus 7th power g and less; to examine the residue and the morphology of the craters produced by these meteoroid; to obtain information regarding the dynamic and physical properties of the meteoroids; and to discover possible correlations with the lunar-rock-crater studies. Photographs are included.

Cour-Palais, B. G.↗

NASA NTRS1973

Synthesis of optically clear polymeric materials for high temperature windows

A polymer has been developed that has excellent potential for use as windows in spacecraft as well as conventional aircraft. This polymer, phenolphthalein polycarbonate, has outstanding thermal properties, e.g., in place of melting or burning, it produces an insulating charred foam that closes off transmission of radiant heat through the window. This fact, coupled with an oxygen index of 0.43 and a 177 C tensile strength of 58 mega Newtons/sq m, makes this polymer a prime candidate for further development. Pilot plant preparation in a 20 gallon Pfaudler kettle was accomplished and large test specimens were prepared for evaluations.

Pannell, C. E.↗

NASA NTRS1973

A computer program to determine the possible daily release window for sky target experiments

A computer program is presented which is designed to determine the daily release window for sky target experiments. Factors considered in the program include: (1) target illumination by the sun at release time and during the tracking period; (2) look angle elevation above local horizon from each tracking station to the target; (3) solar depression angle from the local horizon of each tracking station during the experimental period after target release; (4) lunar depression angle from the local horizon of each tracking station during the experimental period after target release; and (5) total sky background brightness as seen from each tracking station while viewing the target. Program output is produced in both graphic and data form. Output data can be plotted for a single calendar month or year. The numerical values used to generate the plots are furnished to permit a more detailed review of the computed daily release windows.

Michaud, N. H.↗

NASA NTRS1974

Design of the Skylab MDA window

Description of the optical and structural design requirements, mechanical and thermal response analyses, final design features, and testing procedures employed in the development of a large window mounted on the earth-facing side of the multiple docking adapter (MDA) of the Skylab manned space vehicle. This window was designed for the S190 earth resources multispectral camera and was protected from the space environment during nonuse periods by a hinged cover operated from within the MDA. The camera required a viewing area approximately 43 by 58 cm. A single glass pane 4.1 cm thick was selected to minimize optical distortions. Heaters on the glass and frame were designed to control distortions caused by thermal gradients in the glass.

Trent, D. J.↗

NASA NTRS1977

Monitor for optical-window contamination

System uses window itself as principal element of well-known attenuated total reflection technique frequently used for spectroscopic analysis of thin films. Monitor includes notch in monitored window, which acts as beam splitter to reflect portion of light at less than critical angle and causes total internal reflection.

Harnett, L. N.↗

NASA NTRS1976

A moving-window parameter adaptive control system for the F8-DFBW aircraft

This paper describes the moving-window parameter adaptive control system developed for the NASA F8-DFBW aircraft. The control system employs a parameter identification process that, iteratively, adjusts parameters of a model of the aircraft motions in a batch processing manner so that responses generated from the model fit the outputs of sensors stored in a finite record referred to as the moving window. Tests are made on the validity of the parameter estimates before using the parameters in an on-line design process. The on-line design process is an algebraic mapping of the parameters of the model into primary control system feedback and feedforward gains. The mapping was selected to satisfy specific flying quality characteristics over the range of parameter variations expected. Results are presented from simulation studies on the identification algorithm, tests for parameter validity, and the on-line design process.

Montgomery, R. C.↗

NASA NTRS1977

Window comparator

A window comparator is described, comprising two operational amplifiers, one with two feedback circuits, each feedback circuit having a diode connected to the amplifier output and poled for forward current conduction of opposite polarity, to provide an algebraic difference between an input signal and a selected set-point voltage. Differential input terminals of the second operational amplifier were connected to the separate feedback circuits of the first operational amplifier, one input terminal to the output of one diode, and the other to the output of the other diode. A selected window-width voltage was connected through a coupling resistor to one of the input terminals of the second operational amplifier to determine when the algebraic difference of the input signal and the setpoint voltage has exceeded a predetermined tolerance after that difference has changed signs.

Black, J. M.↗

NASA NTRS1977

A moving window parameter adaptive control system for the F8-DFBW aircraft

This paper describes the moving window parameter adaptive control system developed for the NASA F8-DFBW aircraft. The control system employs a parameter identification process that, iteratively, adjusts parameters of a model of the aircraft motions in a batch-processing manner so that responses generated from the model fit the outputs of sensors stored in a finite record referred to as the moving window. Tests are made on the validity of the parameter estimates before using the parameters in an on-line design process. The on-line design process is an algebraic mapping of the parameters of the model into primary control system feedback and feedforward gains. The mapping was selected to satisfy specific flying quality characteristics over the range of parameter variations expected. Results are presented from simulation studies on the identification algorithm made during the development of the system.

Dunn, H. J.↗

NASA NTRS1979

Window with integral seal

Installation concept needed for airtight, watertight, laminated window does away with O-rings and sealants needed for effective edge seal. Pliable inner layer of laminating adhesive extends to form build-in gasket. Technique is usable for plastic or glass windows where space for gaskets and sealing rings is limited, canopies, and shields for military, marine, and land transportation vehicles.

Behar, J. M.↗

NASA NTRS1979

Lens window simplifies TDL housing

Lens window seal in tunable-diode-laser housing replaces plan parallel window. Lens seals housing and acts as optical-output coupler, thus eliminating need for additional reimaging or collimating optics.

Robinson, D. M.↗

NASA NTRS1977

Precision temperature gradient measurements on window glass

Surface temperature gradients were measured with miniature thermocouples installed in a 58.5 cm (23-inch) square window. Test measurements at 25 locations were made under vacuum and with the window operating in radiant heat transfer mode. The analysis of thermocouple design and installation is presented along with a lead wire routing scheme to allow for both differential and absolute temperature measurements while using a minimum number of signal feedthru paths through the test chamber wall. Typical test data and operational precautions are presented along with the accuracy analysis for installation effects and measurement effects to support differential temperature measurement precision values of + or - 0.06 C RMS + or - 0.1 F RMS).

Mikk, G.↗

NASA NTRS1979

Vibration characteristics of walls and a plate glass window representative of those of a wood-frame house

Mechanical excitation was used, and measurements of acceleration response, natural frequencies, and nodal patterns were performed. Results indicate that the wall sections and the complete wall did not act as a unit in responding to sinusoidal vibration inputs. Calculated frequencies of the components that account for this independent behavior of the studs and face sheets agreed resonably well with experimental frequencies. Experimental vibrations of the plate glass window agreed with the calculated behavior, and responses of the window exposed to airplane flyover noise were readily correlated with the test results.

Carden, H. D.↗

NASA NTRS1979

Acoustic response of thin film windows in the environment of an Atlas-Centaur launch

An exhaustive design development study was performed to correlate the survivability of thin film to various parameters. Film material properties, film thicknesses, unsupported window areas, window aspect ratios, film/frame transitions, film reinforcing techniques, and material grain orientations were all considered. Several thin films were tested to acoustical loads which are expected during an Atlas-Centaur launch of the High Energy Astronomy Observatory Satellites (HEAO)

Mastronardi, R.↗

NASA NTRS1979

Phosphine absorption in the 5-micron window of Jupiter

Since the original suggestion by Gillett et al. (1969) it has generally been assumed that the region of partial transparency near 5 micron in Jupiter's atmosphere (the 5-micron window) is bounded by the nu sub 4 NH3 at 6.1 micron and the nu sub 3 CH4 band at 3.3 micron. New measurements of Jupiter and of laboratory phosphine (PH3) samples show that PH3 is a significant contributor to the continuum opacity in the window and in fact defines its short-wavelength limit. This has important implications for the use of 5-micron observations as a means to probe the deep atmospheric structure of Jupiter. The abundance of PH3 which results from a comparison of Jovian and laboratory spectra is about 3 to 5 cm-am. This is five to eight times less than that found by Larson et al. (1977) in the same spectral region, but is in good agreement with the result of Tokunaga et al. (1979) from 10-micron observations.

Beer, R.↗

NASA NTRS1980

Design windows for low-high-low GaAs IMPATT's

The paper presents a low-high-low GaAs IMPATT model used to define design windows at the frequency of interest. Emphasis is placed on experimental verification confirming both the utility of the model and the design windows obtained therefrom. It is noted that the model can be also useful during fabrication.

Namordi, M. R.↗

NASA NTRS1980

Design and use of a servo-controlled high pressure window bomb in spectroscopic studies of solid propellant combustion

The feasibility of using a high pressure window bomb as a laboratory scale model of actual motor conditions. The design and operation of a modified high pressure window bomb is discussed. An optical servocontrol mechanism has been designed to hold the burning surface of a propellant strand at a fixed position within the bomb chamber. This mechanism permits the recording of visible and infrared emission spectra from various propellants. Preliminary visible emission spectra of a nonmetalized and metalized propellant are compared with spectra recorded using the modified bomb.

Goetz, F.↗

NASA NTRS1983

Low-level water vapor fields from the VAS split-window channels at 11 and 12 microns

Originally, the VAS split window channels were designed to use the differential water vapor absorption between 11 and 12 microns to estimate sea surface temperature by correcting for the radiometric losses caused by atmospheric moisture. It is shown that it is possible to reverse the procedure in order to estimate the vertically integrated low level moisture content with the background surface (skin) temperature removed, even over the bright, complex background of the land. Because the lower troposphere's water vapor content is an important factor in convective instability, the derived fields are of considerable value to mesoscale meteorology. Moisture patterns are available as quantitative fields (centimeters of precipitable water) at full VAS resolution (as fine as 7 kilometers horizontal resolution every 15 minutes), and are readily converted to image format for false color movies. The technique, demonstrated with GOES-5, uses a sequence of split window radiances taken once every 3 hours from dawn to dusk over the Eastern and Central United States. The algorithm is calibrated with the morning radiosonde sites embedded within the first VAS radiance field; then, entire moisture fields are calculated at all five observation times. Cloud contamination is removed by rejecting any pixel having a radiance less than the atmospheric brightness determined at the radiosonde sites.

Chesters, D.↗

NASA NTRS1984

Field repair of AH-16 helicopter window cutting assemblies

The U.S. Army uses explosively actuated window cutting assemblies to provide emergency crew ground egress. Gaps between the system's explosive cords and acrylic windows caused a concern about functional reliability for a fleet of several hundred aircraft. A field repair method, using room temperature vulcanizing silicone compound (RTV), was developed and demonstrated to fill gaps as large as 0.250 inch.

Bement, L. J.↗