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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 1,099 records · Page 61
All sourcesNASA NTRSDOE OSTI
NASA NTRS1983

Operation and maintenance requirements of the Army Remotely Piloted Vehicle (RPV)

The Remotely Piloted Vehicle (RPV) system is being developed to provide the Army with a target acquistion, target location, and laser designation capability that will significantly enhance the effectiveness of the artillery. Iterative analyses of the manpower, personnel, and training (MPT) requirements for an RPV system configured to accommodate both a daylight television and a forward looking infrared (FLIR) mission payload subsystem (FMPS) and related support subsystems are examined. Additionally, this analysis incorporates a 24 hour-a-day operational scenario. Therefore, the information presented was developed with a view towards delineating the differences (or deltas) imposed by the new requirements resulting from FMPS/24 hour operating day functions.

Source record↗
NASA NTRS1985

Langley Research Center Photogrammetric Measurements of Solar Array Dynamics: Preliminary Results

The NASA Langley Research Center participated in the Solar Array Experiment with two primary objectives: (1) to study the structural and control dynamics of a new class of large, lightweight, low-frequency space structures, and (2) to develop technology for remote video measurement of structural motions. The shuttle orbiter's closed circuit television (CCTV) system was used to provide recorded video images of the solar array from four locations in the payload bay, two on the forward bulkhead and two on the aft bulkhead. White reflective targets were placed on the array to provide discrete points at which to track array motion. A dynamic test consisted of a quiescent period in which orbiter operations were inhibited and crew motion restricted, an excitation period, and a free decay period. The orbiter was placed in free drift while in a gravity gradient orientation and dynamics tests were timed to occur at orbital noon so that the Sun would illuminate one side of the array and Earth albedo the other. The CCTV system was turned on during the quiescent period, approximately 3 minutes prior to excitation. Video from all four CCTV cameras was recorded continuously through the excitation and free-decay periods for a total test record of 8 to 10 minutes.

Brumfield, M. L.↗
NASA NTRS1985

Space Experiments with Particle Accelerators (SEPAC)

The space experiments with particle accelerators (SEPAC) instruments consist of an electron accelerator, a plasma accelerator, a neutral gas (N2) release device, particle and field diagnostic instruments, and a low light level television system. These instruments are used to accomplish multiple experiments: to study beam particle interactions and other plasma processes; as probes to investigate magnetospheric processes; and as perturbation devices to study energy coupling mechanisms in the magnetosphere, ionosphere, and upper atmosphere.

Roberts, W. T.↗
NASA NTRS1984

Comparative measurements using different particle size instruments

This paper discusses the measurement and comparison of particle size and velocity measurements in sprays. The general nature of sprays and the development of standard, consistent research sprays are described. The instruments considered in this paper are: pulsed laser photography, holography, television, and cinematography; laser anemometry and interferometry using visibility, peak amplitude, and intensity ratioing; and laser diffraction. Calibration is by graticule, reticle, powders with known size distributions in liquid cells, monosize sprays, and, eventually, standard sprays. Statistical analyses including spatial and temporal long-time averaging as well as high-frequency response time histories with conditional sampling are examined. Previous attempts at comparing instruments, the making of simultaneous or consecutive measurements with similar types and different types of imaging, interferometric, and diffraction instruments are reviewed. A program of calibration and experiments for comparing and assessing different instruments is presented.

Chigier, N.↗
NASA NTRS1983

An allpass filter design for luminance and chrominance separation of NTSC signals

Abstract- Digital techniques for separation of luminance and chrominance components from composite NTSC broadcast television signals are explored. First, comb filters are introduced. Secondly, filters based on linear regression are developed. Finally, a third filtering form, the allpass filter is considered. Techniques are compared based on mean squared error criteria and subjective testing. It is demonstrated that the allpass filtering technique is superior to both the comb filtering as well as the regression filtering.

Border, D. A.↗
NASA NTRS1983

On the subjective evaluation of the interference protection ratios' measurements for co-channel FM-TV signals

Results of subjective measurements made to determine the relationship between the image impairment grade and the wanted-signal to interference power ratios (C/I) for co-channel FM television signals are presented. The variation of C/I ratio with picture impairment grade is investigated for three different noise levels. The assessment of impairment grade due to thermal noise only and to picture content is also investigated. A statistical analysis for performed experiments is presented. The results presented here may be used by communication system designers to determine the required system characteristics.

Groumpos, P. P.↗
NASA NTRS1985

Experimental results supporting the determination of service quality objectives for DBS systems

A summary of the results of a joint United States and Canadian program on subjective measurements of the picture degradation caused by noise and interference on an NTSC encoded color television signal is given in this paper. The effects of system noise, cochannel and adjacent channel interference, and both single entry and aggregate as well as a combination of these types of interference were subjectively evaluated by expert and nonexpert viewers under reference conditions. These results were used to develop the rationale used at RARC '83 to establish the service quality objective for planning the DBS service for the American continents.

Chouinard, G.↗
NASA NTRS1985

The Hopkins ultraviolet telescope

The Shuttle is scheduled to carry the Hopkins UV Telescope (HUT) aloft in 1986. HUT will be one of three telescopes on the mission and will be sensitive to the 450-1800 A interval. Its primary goals will be observations of Halley's Comet, the planets, distant galaxies and quasars. It will be controlled by Spacelab personnel and features a 0.9 m primary mirror, a spectrograph on the focal plane, and an Si intensified image television camera for on-line image monitoring. The main component of the spectrograph will be a 1024 channel self-scanning Reticon photodiode array coupled by optic fibers to the microchannel detector plates. HUT is presently undergoing qualification testing.

Davidsen, A. F.↗
NASA NTRS1985

Wave-particle interactions induced by SEPAC on Spacelab 1 Wave observations

Space experiments with particle accelerators (SEPAC) flew on Spacelab 1 in November and December 1983. SEPAC included an accelerator which emitted electrons into the ionospheric plasma with energies up to 5 keV and currents up to 300 mA. The SEPAC equipment also included an energetic plasma generator, a neutral gas generator, and an extensive array of diagnostics. The diagnostics included plasma wave detectors, and energetic electron analyzer, a photometer, a high sensitivity television camera, a Langmuir probe and a pressure gage. Twenty-eight experiments were performed during the mission to investigate beam-plasma interactions, electron beam dynamics, plasma beam propagation, and vehicle charging. The wave-particle interactions were monitored by the plasma wave instrumentation, by the energetic electron detector and by the optical detectors. All show evidence of wave-particle interactions, which are described in this paper.

Taylor, W. W. L.↗
NASA NTRS1984

Eye directed view

This paper presents the concept of extended intelligence and describes modifications to a commercially available automaton, using state-of-the-art technology, that demonstrates the practical use of extended intelligence. The natural inclination of an operator to look beyond the boundaries of a work scene as presented on a video monitor is used to command the pan and tilt of television cameras. In a teleoperator system, this capability allows the natural expansion of a work scene without burdening the operator with either a trivial cerebral task or a time consuming motor task. The automaton is unobtrusive, allows complete operator freedom, and approaches full dependability of command response with minimal operator orientation.

Goode, P. W.↗
NASA NTRS1985

Fluctuations of precipitated electron intensity in flickering auroral arcs

Electron spectra associated with two aurorae observed by ground-based television are reported. One auroral arc was observed to flicker, large variations in the precipitated electron energy occurring on a time scale of 114 ms. The major variations occur at the higher energies of the 0.5-20 keV range covered by the detectors. Changes in the particle flux occur primarily in the pitch angle range 0 to 60 deg. Analysis of the video data shows a larger variation in intensity along the lower border of the arc in keeping with the results of the electron spectra. The second arc was not observed to flicker, and the associated electron spectra and video data show no large variations in precipitated electron energy or video intensity modulation. While pitch-angle distributions tend to be field-aligned in the first arc, the distributions in the second arc are nearly isotropic or peaked from 60 to 90 deg in the downward hemisphere.

Spiger, R. J.↗
NASA NTRS1986

TV Video-Level Controller

Constant output maintained, though luminance varies by 5 million to 1. Three means of normalizing video output utilized in video-level controller: iris adjustment, tube voltage adjustment, and automatic gain control. With aid of automatic light control and gain control, television camera accommodates maximum light level 5 million times greater than lowest light level, while outputting constant 3-V peak signal to processing circuitry.

Kravitz, M.↗
NASA NTRS1986

Unbalanced-to-Balanced Video Interface

Equal but opposite video waveforms generated. Unbalanced input line terminated in 75-ohm resistor, R1. Capacitor C1 blocks dc component of input so only time-varying component fed to Q1 and inverted in polarity. Circuit intended for use with input television signal having polarity, amplitude, and dc bias such that tips of synchronizing pulses lie at zero volts while reference white level is specified positive dc level (typically about 1 volt).

Richardson, J. E.↗
NASA NTRS1986

Photocurrent Imaging Detects Solar-Module Defects

Raster-scanned laser beam excites photocurrents in thin-film amorphous silicon devices. Solar-cell laser scanner uses two galvanometer-driven mirrors to scan laser-beam spot over surface of module or cell under test. Position signals from scan controllers used to index storage of photocurrent signal data in scan-converter image memory. Stored image displayed on television monitor.

Kim, Q.↗
NASA NTRS1985

Increased productivity in flight with voice commanding

Automatic Speech Recognition technology has matured to the point where it can provide a viable means of increasing productivity by naturalizing the man-machine interface. With ever increasing workloads being placed on astronauts, speech recognition may provide an alternative means of system controlling that would reduce the task burden. Voice commanding, allowing hands-free operation, can be especially effective during operations requiring simultaneous system control. A flight experiment is under development to demonstrate the operational effectiveness of voice control by commanding the Space Shuttle's Closed Circuit Television (CCIV) system. This experiment will help direct future applications of voice entry to space operations.

Jordan, W. T.↗
NASA NTRS1985

Optical observations of the AMPTE artificial comet and magnetotail barium releases

The first AMPTE artificial comet was observed with a low light level television camera operated aboard the NASA CV990 flying out of Moffett Field, California. The comet head, neutral cloud, and comet tail were all observed for four minutes with an unifiltered camera. Brief observations at T + 4 minutes through a 4554A Ba(+) filter confirmed the identification of the structures. The ion cloud expanded along with the neutral cloud at a rate of 2.3 km/sec (diameter) until it reached a final diameter of approx. 170 km at approx. T + 90 s. It also drifted with the neutral cloud until approx. 165 s. By T + 190 s it had reached a steady state velocity of 5.4 km/sec southward. A barium release in the magnetotail was observed from the CV990 in California, Eagle, Alaska, and Fairbanks, Alaska. Over a twenty-five minute period, the center of the barium streak drifted southward (approx. 500 m/sec), upward (24 km/sec) and eastward (approx 1 km/sec) in a nonrotating reference frame. An all-sky TV at Eagle showed a single auroral arc in the far North during this period.

Hallinan, T. J.↗
NASA NTRS1986

Space experiments with particle accelerators: SEPAC

The SEPAC instruments consist of an electron accelerator, a plasma accelerator, a neutral gas (N2) release device, particle and field diagnostic instruments, and a low light level television system. These instruments are used to accomplish multiple experiments: to study beam-particle interactions and other plasma processes; as probes to investigate magnetospheric processes; and as perturbation devices to study energy coupling mechanisms in the magnetosphere, ionosphere, and upper atmosphere.

Roberts, B.↗