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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 703 records · Page 39
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

Optical Shaft-Angle Encoder For Helicopter Rotor

Angular position of helicopter rotor blade determined precisely. Accomplished by use of optical shaft-angle encoder called "256 Ring" on rotor swashplate. Each 360 degree rotation of helicopter main rotor broken down into 256 reflective segments. As rotor rotates, beam of light reflected in turn from each segment into optoelectronic system. One of 256 segments reflects larger pulse than others do. Position of rotor determined by counting number of pulses after this reference pulse. While swashplate mounting requirements unique to each type of helicopter, concept applicable to all types of rotorcraft.

Golub, Robert A.↗
NASA NTRS1993

Shaft-Motion-Analyzing System

Optoelectronic system to monitor motions of turbopump shaft developed. Optical sensors detect passage of reflective triangles on shaft. Optical measurements processed in real time into indications of speed of rotation and of axial and lateral displacements of shaft.

Randall, Richard L.↗
NASA NTRS1993

Photodetector Array For Neural Network

Integrated circuit performs 1,024 threshold operations in parallel. Designed for use in postprocessing output of optical correlator in optoelectronic neural network. Overall function of device to put out digital signals indicative of location(s) of bright spot(s) on detector plane. Response time less than commercial charge-coupled-device (CCD) imaging detector operating at standard television frame rate.

Langenbacher, Harry↗
NASA NTRS1993

Wavelength-Division Multiplexing Of Avionic Digital Control Signals

Proposed wavelength-division multiplexing optoelectronic system aboard aircraft transmits digital control signals from central flight-control computer via optical fibers to multiple distributed processors, actuators, and sensors. In comparison with serial TDM communication systems, this system offers potentially higher data throughput, greater tolerance to transient induced faults, and lower bit-error rates. Also immune to electromagnetic interference at suboptical frequencies.

Patterson, James D.↗
NASA NTRS1993

Subsurface Growth Of Silicide Structures In Silicon

Technique shows promise for fabrication of novel electronic, optoelectronic, and electro-optical devices. Experiments demonstrated feasibility of growing microscopic single-crystal CoSi2 structures beneath surfaces of Si substrates.

Fathauer, Robert W.↗
NASA NTRS1992

Developments on high temperature fiber optic microphone

A fiber optic microphone, based on the principle of the fiber optic lever, features small size, extended bandwidth, and capability to operate at high temperatures. These are requirements for measurements in hypersonic flow. This paper describes the principles of operation of fiber optic sensors, a discussion of the design of a fiber optic microphone, the functional elements and packaging techniques of the optoelectronic circuitry, and the calibration techniques used in the development of the high temperature fiber optic microphone.

Wright, Kenneth D., II↗
NASA NTRS1993

Wireless infrared communications for space and terrestrial applications

Voice and data communications via wireless (and fiberless) optical means has been commonplace for many years. However, continuous advances in optoelectronics and microelectronics have resulted in significant advances in wireless optical communications over the last decade. Wilton has specialized in diffuse infrared voice and data communications since 1979. In 1986, NASA Johnson Space Center invited Wilton to apply its wireless telecommunications and factory floor technology to astronaut voice communications aboard the shuttle. In September, 1988 a special infrared voice communications system flew aboard a 'Discovery' Shuttle mission as a flight experiment. Since then the technology has been further developed, resulting in a general purpose of 2Mbs wireless voice/data LAN which has been tested for a variety of applications including use aboard Spacelab. Funds for Wilton's wireless IR development were provided in part by NASA's Technology Utilization Office and by the NASA Small Business Innovative Research Program. As a consequence, Wilton's commercial product capability has been significantly enhanced to include diffuse infrared wireless LAN's as well as wireless infrared telecommunication systems for voice and data.

Crimmins, James W.↗
NASA NTRS1992

Texturing of InP surfaces for device applications

A unique process for texturing InP (100) wafers by anisotropic etching was developed. The process produces irregular V-grooves on the surface, which reduce the surface reflectivity. The process does not require photolithography or masking. The etching characteristics depend on doping, with etching tending to proceed more rapidly on the more heavily doped samples. Reduced reflectivity surfaces formed using this process can be applied to solar cells, photodetectors, and other optoelectronic devices.

Bailey, Sheila G.↗
NASA NTRS1990

Space applications for high temperature superconductivity - Brief review

An overview is presented of materials and devices based on high-temperature superconductivity (HTS) that could have useful space-oriented applications. Of specific interest are applications of HTS technologies to mm and microwave systems, spaceborne and planet-surface sensors, and to magnetic subsystems for robotic, rescue, and docking maneuvers. HTS technologies can be used in optoelectronics, magnetic-field detectors, antennae, transmission/delay lines, and launch/payload coils.

Krishen, Kumar↗
NASA NTRS1992

Hazard detection and avoidance sensor for NASA's planetary landers

An optical terrain analysis based sensor system specifically designed for landing hazard detection as required for NASA's autonomous planetary landers is introduced. This optical hazard detection and avoidance (HDA) sensor utilizes an optoelectronic wedge-and-ting (WRD) filter for Fourier transformed feature extraction and an electronic neural network processor for pattern classification. A fully implemented optical HDA sensor would assure safe landing of the planetary landers. Computer simulation results of a successful feasibility study is reported. Future research for hardware system implementation is also provided.

Lau, Brian↗
NASA NTRS1992

Fiber optic rotation sensor for long lifetime space missions

The present F-O rotation sensors (FORS) are all-solid state devices for measuring rotations and rotation rates in inertial space that may reach the 0.003 deg/hr (1-sigma) accuracies required for NASA's Saturn-orbiting Cassini mission. Attention is presently given to the mission, inertial reference unit, and FORS instrument optoelectronic component requirements envisioned for such spacecraft applications.

Dorsky, L.↗
NASA NTRS1993

Fiber optic smart structures and skins V; Proceedings of the Meeting, Boston, MA, Sept. 8, 9, 1992

The present conference discusses the materials used in applications of fiber-optics (F-O) to smart structures, extrinsic Fabry-Perot interferometric F-O sensors, sapphire F-O sensors, two-mode F-O sensors with photoinduced refractive index, an F-O accelerometer using two-mode fibers, and embedded F-O acoustic sensors for flaw detection. Also discussed are an optoelectronic smart structure interface, F-O sensors for simultaneous detection of strain and temperature, an optical Mach-Zehnder interferometer for smart skins, a split-cavity cross-coupled extrinsic fiber interferometer, and an embedded Bragg grating F-O sensor for composite flexbeams, an Er-doped ring-laser strain sensor.

Claus, Richard O.↗
NASA NTRS1992

Lattice-matched heteroepitaxy of wide gap ternary compound semiconductors

A variety of applications are identified for heteroepitaxial structures of wide gap I-III-VI2 and II-IV-V2 semiconductors, and are assessed in comparison with ternary III-V alloys and other wide gap materials. Non-linear optical applications of the I-III-VI2 and II-IV-V2 compound heterostructures are discussed, which require the growth of thick epitaxial layers imposing stringent requirements on the conditions of heteroepitaxy. In particular, recent results concerning the MOCVD growth of ZnSi(x)Ge(1-x)P2 alloys lattice-matching Si or GaP substrates are reviewed. Also, heterostructures of Cu(z)Ag(1-z)GaS2 alloys that lattice-match Si, Ge, GaP or GaAs substrates are considered in the context of optoelectronic devices operating in the blue wavelength regime. Since under the conditions of MOCVD, metastable alloys of the II-IV-V2 compounds and group IV elements are realized, II-IV-V2 alloys may also serve as interlayers in the integration of silicon and germanium with exactly lattice-matched tetrahedrally coordinated compound semiconductors, e.g. ZnSi(x)Ge(1-x)P2.

Bachmann, Klaus J.↗
NASA NTRS1991

Photonics: Technology project summary

Photonics involves the use of light (photons) in conjunction with electronics for applications in communications, computing, control, and sensing. Components used in photonic systems include lasers, optical detectors, optical wave guide devices, fiber optics, and traditional electronic devices. The goal of this program is to develop hybrid optoelectronic devices and systems for sensing, information processing, communications, and control. It is hoped that these new devices will yield at least an order of magnitude improvement in performance over existing technology. The objective of the program is to conduct research and development in the following areas: (1) materials and devices; (2) networking and computing; (3) optical processing/advanced pattern recognition; and (4) sensing.

Depaula, Ramon P.↗
NASA NTRS1994

Low-Reflectance Surfaces For Solar Cells

Improved method for increasing solar cell efficiency has potential application for space-based and terrestrial solar power systems and optoelectronic devices. Etched low-angle grooves help recover reflected light. Light reflected from v-grooved surface trapped in cover glass and adhesive by total internal reflection. Reflected light redirected onto surface, and greater fraction of incident light absorbed, producing more electrical energy in InP solar photovoltaic cell.

Bailey, Sheila G.↗
NASA NTRS1994

Optical Measurement Of Propfan Deflections

Optoelectronic system measures deflections of rotating propfan. In addition to 0.5-mW HeNe lasers, system includes Schottky-barrier photodetectors, neutral-density filters, signal amplifiers, output-signal-recording device, and digitizer. Laser beam passes through plane of rotation of propfan blades. Beam is one of three that measure displacements at different blade sections. Additional laser beam at bottom generates shaft-rotation timing signal.

Ramsey, John K.↗
NASA NTRS1994

Synchronized Flashing Lights For Approach And Docking

Proposed optoelectronic system for guiding vehicle in approaching and docking with another vehicle includes active optical targets (flashing lights) on approached vehicle synchronized with sensor and image-processing circuitry on approaching vehicle. Conceived for use in automated approach and docking of two spacecraft. Also applicable on Earth to manually controlled and automated approach and docking of land vehicles, aircraft, boats, and submersible vehicles, using GPS or terrestrial broadcast time signals for synchronization. Principal advantage: optical power reduced, with consequent enhancement of safety.

Book, Michael L.↗
NASA NTRS1994

Simplified Generation Of Distance Images

Optoelectronic apparatus undergoing development intended to produce digitized images that contain three-dimensional information: brightness of each picture element in digitized image depends on distance from apparatus to corresponding location in scene. Does not contain mechanical scanners. Signal-processing circuitry in this apparatus simpler. Smaller, weighs less, and consumes less power. Potential applications include automated inspection, remote exploration, robotic manipulators, robotic vehicles, and maneuvering and docking systems.

Wesolowicz, Karl↗