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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 379 records · Page 21

Performance analysis of wideband data and television channels

Several aspects are discussed of space shuttle communications, including the return link (shuttle-to-ground) relayed through a satellite repeater (TDRS). The repeater exhibits nonlinear amplification and an amplitude-dependent phase shift. Models were developed for various link configurations, and computer simulation programs based on these models are described. Certain analytical results on system performance were also obtained. For the system parameters assumed, the results indicate approximately 1 db degradation relative to a link employing a linear repeater. While this degradation is dependent upon the repeater, filter bandwidths, and modulation parameters used, the programs can accommodate changes to any of these quantities. Thus the programs can be applied to determine the performance with any given set of parameters, or used as an aid in link design.

Geist, J. M.↗

Ultraviolet television data from the orbiting astronomical observatory. II - Stellar ultraviolet colors and interstellar extinction

The results from the Celescope Catalog of Ultraviolet Stellar Observations (Davis, Deutschman, and Haramundanis 1973) are studied, emphasizing statistical groups and subgroups of stars. In spite of the rather large observational errors, the great number of Celescope observations make it possible to do that kind of study with reasonable accuracy. Some stars have ultraviolet colors that differ significantly from those of the group to which they have been assigned on the basis of ground-based observations. An attempt is made to describe the general properties of the ultraviolet colors of the stars as observed by the Celescope experiment on board NASA's Orbiting Astronomical Observatory (OAO-2). Besides the direct applicability of these results to the general study of stellar atmospheres and of interstellar extinction, they are also considered as a frame of reference for further studies of individual stars and groups of stars.

Peytremann, E.↗

Design of a video system providing optimal visual information for controlling payload and experiment operations with television

A program was conducted which included the design of a set of simplified simulation tasks, design of apparatus and breadboard TV equipment for task performance, and the implementation of a number of simulation tests. Performance measurements were made under controlled conditions and the results analyzed to permit evaluation of the relative merits (effectivity) of various TV systems. Burden factors were subsequently generated for each TV system to permit tradeoff evaluation of system characteristics against performance. For the general remote operation mission, the 2-view system is recommended. This system is characterized and the corresponding equipment specifications were generated.

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Payload operation television system

The TV system assembled is intended for laboratory experimentation which would develop operational techniques and lead to the design of space-borne TV equipment whose purpose would be to assist the astronaut-operator aboard a space station to load payload components. The TV system assembled for this program is a black and white, monocular, high performance system. The equipment consists principally of a good quality TV camera capable of high resolving power; a TV monitor; a sync generator for driving camera and monitor; and two pan/tilt units which are remotely controlled by the operator. One pan/tilt unit provides control of the pointing of the camera, the other similarly controls the position of a simulated payload.

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Detailed design package for design of a video system providing optimal visual information for controlling payload and experiment operations with television

A detailed description of a video system for controlling space shuttle payloads and experiments is presented in the preliminary design review and critical design review, first and second engineering design reports respectively, and in the final report submitted jointly with the design package. The material contained in the four subsequent sections of the package contains system descriptions, design data, and specifications for the recommended 2-view system. Section 2 contains diagrams relating to the simulation test configuration of the 2-view system. Section 3 contains descriptions and drawings of the deliverable breadboard equipment. A description of the recommended system is contained in Section 4 with equipment specifications in Section 5.

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Television systems for remote manipulation

An analytical and experimental study was conducted to specify a video system for remote manipulation in space. An operator function analysis identified two basic characteristics, work volume and element relationship, which define four manipulation tasks chosen for examination. A visual function analysis developed a set of elemental scene parameters which grouped the visual dimensions into major areas of influence. Simulation testing was conducted with a four degree-of-freedom motion frame which allowed an operator to perform the manipulation tasks. Four video systems were included in the simulation testing: a black and white and a color monoscopic system, a stereoscopic system, and a black and white two-view system. A sequential experimental plan first provided an overall analysis of the effects of tasks, scene parameters, and video systems. This was followed by a detailed experimental examination of the critical dimensions identified in the first experiment. Results are discussed in terms of a recommended TV system.

Crooks, W. H.↗

Solid State Television Camera (CID)

The design, development and test are described of a charge injection device (CID) camera using a 244x248 element array. A number of video signal processing functions are included which maximize the output video dynamic range while retaining the inherently good resolution response of the CID. Some of the unique features of the camera are: low light level performance, high S/N ratio, antiblooming, geometric distortion, sequential scanning and AGC.

Steele, D. W.↗

Television applications of interline-transfer CCD arrays

The design features and characteristics of interline transfer (ILT) CCD arrays with 190 x 244 and 380 x 488 image elements are reviewed, with emphasis on optional operating modes and system application considerations. It was shown that the observed horizontal resolution for a TV system using an ILT image sensor can approach the aperture response limit determined by photosensor site width, resulting in enhanced resolution for moving images. Preferred camera configurations and read out clocking modes for maximum resolution and low light sensitivity are discussed, including a very low light level intensifier CCD concept. Several camera designs utilizing ILT-CCD arrays are described. These cameras demonstrate feasibility in applications where small size, low-power/low-voltage operation, high sensitivity and extreme ruggedness are either desired or mandatory system requirements.

Hoagland, K. A.↗

Future planetary television cameras

The evolution of planetary slow-scan vidicon cameras started with the exploratory flyby mission to Mars in 1965, and has continued through the planned launch of the Mariner Jupiter/Saturn 1977 Mission. To date, the camera performance has been constrained by limited spacecraft capabilities rather than driven by desires of experimenters. The paper traces this evolution for a generation of camera using charge-coupled device (CCD) sensors, which have greater capability within spacecraft weight and power constraints. Projections are given of scientific objectives for the CCD cameras, and it is shown how these objectives will drive the camera performance, data rates, on-board processing, pointing accuracy, and other spacecraft system parameters.

Norris, D. D.↗

Observing and recording instantaneous images on ATM television monitors

A persistent image-converter device was utilized to make visible to the astronaut solar images that were isolated, instantaneous flashes on the ATM TV monitors. In addition, these instantaneous images, as well as normal TV images, were recorded with a Polaroid SX-70 camera for study by the astronauts.

Patterson, N. P.↗

Sharing the 620-790 MHz band allocated to terrestrial television with an audio-bandwidth social service satellite system

A study was carried out to identify the optimum uplink and downlink frequencies for audio-bandwidth channels for use by a satellite system distributing social services. The study considered functional-user-need models for five types of social services and identified a general baseline system that is appropriate for most of them. Technical aspects and costs of this system and of the frequency bands that it might use were reviewed, leading to the identification of the 620-790 MHz band as a perferred candidate for both uplink and downlink transmissions for nonmobile applications. The study also led to some ideas as to how to configure the satellite system.

Smith, E. K.↗

Television observations of Mercury by Mariner 10

The morphology and optical properties of the surface of Mercury resemble those of the Moon in remarkable detail, recording a very similar sequence of events; chemical and mineralogical similarity of the outer layers is implied. Mercury is probably a differentiated planet with an iron-rich core. Differentiation is inferred to have occurred very early. No evidence of atmospheric modification of any landform is found. Large-scale scarps and ridges unlike lunar or Martian features may reflect a unique period of planetary compression near the end of heavy bombardment, perhaps related to contraction of the core.

Murray, B. C.↗

A low light level television system

A proposal was submitted in response to the announcement of opportunities for Skylab 1 involving low light level imaging techniques. While the observational objectives are not necessarily pertinent to cometary experimentation and observation the instrumentation possibly would be, and is potentially available if the proposal is successful. The proposed observations are of natural and induced atmospheric glows and near vehicle aerosol distribution.

Duncan, B. J.↗

A computer controlled television detector for light, X-rays and particles

A versatile, high resolution, software configurable, two-dimensional intensified vidicon quantum detector system has been developed for multiple research applications. A thin phosphor convertor allows the detection of X-rays below 20 keV and non-relativistic particles in addition to visible light, and a thicker scintillator can be used to detect X-rays up to 100 keV and relativistic particles. Faceplates may be changed to allow any active area from 1 to 40 mm square, and active areas up to 200 mm square are possible. The image is integrated in a digital memory on any software specified array size up to 4000 x 4000. The array size is selected to match the spatial resolution, which ranges from 10 to 100 microns depending on the operating mode, the active area, and the photon or particle energy. All scan and data acquisition parameters are under software control to allow optimal data collection for each application.

Kalata, K.↗

Television broadcast from space systems: Technology, costs

Broadcast satellite systems are described. The technologies which are unique to both high power broadcast satellites and small TV receive-only earth terminals are also described. A cost assessment of both space and earth segments is included and appendices present both a computer model for satellite cost and the pertinent reported experience with the Japanese BSE.

Cuccia, C. L.↗

Finding Bright-Spot Coordinates in Television Images

Circuit provides data for computer to calculate coordinates of bright spot of light in video image. Calculation performed while image being scanned, and results available immediately at end of video frame. Video-processing circuit has variety of potential uses in commerce and industry. For example, locates tagged-parts on factory assembly line or track airplane landing lights.

Richardson, T. E.↗