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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 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Malfunction of Television Camera Monitor on Command Module

The command module television camera monitor exhibited loss of horizontal synchronization during the initial usage. This condition cleared and performance of the monitor was normal until the press conference telecast during the transearth coast phase. At that time, the monitor had the same horizontal synchronization problem reported during the initial usage. The horizontal hold control adjustment would not correct the condition. The monitor was turned off for approximately 5 minutes, then turned back on, after which the monitor's picture was normal. The loss of horizontal synchronization was most likely caused by either an intermittent condition in the precision voltage regulator circuit assembly in the low voltage power supply, or the shift of the stable range of the horizontal potentiometer setting when warming up after turn-on.

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NASA NTRS1972

Studies relating to FM television and telemetry transmitters

The Auburn University Model S-2 FM television transmitter was examined to determine if the performance and reliability could be improved by application of new techniques and devices developed since completion of the original design work. In particular this study examined the possibility of increased use of integrated circuits. It was determined that improvements in both performance and reliability were possible. In addition a study was conducted to determine the feasibility of converting the transmitter to handle telemetry signals. The study revealed that this conversion was feasible and the modifications were made to the prototype model for verification.

Albritton, W. P.↗
NASA NTRS1972

The development of hurricane Inez, 1966, as shown by satellite nighttime radiometric and daytime television coverage

A complete documentation of Numbus 2 High Resolution infrared Radiometer data and ESSA-1 and 3 television photographs is presented for the life-time of Hurricane Inez, 1966. Ten computer produced radiation charts were analyzed in order to delineate the three dimensional cloud structure during the formative, mature and dissipating stages of this tropical cyclone. Time sections were drawn throughout the storm's life cycle to relate the warm core development and upper level outflow of the storm with their respective cloud canopies, as shown by the radiation data. Aerial reconnaissance weather reports, radar photographs and conventional weather analyses were used to complement the satellite data. A computer program was utilized to accept Nimbus 2 HRIR equivalent blackbody temperatures within historical maximum and minimum sea surface temperature limits over the tropical Atlantic Ocean.

Allison, L. J.↗
NASA NTRS1973

Apollo 15 mission. Temporary loss of command module television picture

An investigation was made into the temporary loss of command module color television picture by the ground station converter at Mission Control Center. Results show the picture loss was caused by a false synchronization pulse that resulted from the inability of the black level clipping circuit to respond adequately to the video signal when bright sunlight suddenly entered the camera's field of view.

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NASA NTRS1973

Mariner Mars 1971 television picture catalog: Sequence design and picture coverage, volume 2, addendum 1

This addendum to the Mariner Mars 1971 Television Picture Catalog, Volume 2 (for abstract, see N73-20850) contains data for the Mariner 9 TV pictures taken after Rev 262. Some of the data presented in Volume 2 is brought up to date. The new provisional mapping pole is discussed, and tables provide the latitude and longitude with respect to the new pole, prime meridian, and rotation rate for the centerpoints of all the Mariner 9 TV pictures.

Koskela, P. E.↗
NASA NTRS1973

Television multiplexing system

A television multiplexing system which includes a circuit that inserts a digital codes sync signal and a digital code into a video signal for identifying the channel is described. The digital sync signal and the digital coded signals are generated by a single crystal controlled clock so that they are always in synchronism with each other. In demultiplexing the signals are utilized for shifting the digital coded signals into a shift register. The shift register, in turn, activates a decoder according to the code stored in the shift register for selecting the proper recording disk or receiver for storing the video signal.

Simpkins, L. G.↗
NASA NTRS1973

A user's guide to the Mariner 9 television reduced data record

The Mariner 9 television experiment used two cameras to photograph Mars from an orbiting spacecraft. For quantitative analysis of the image data transmitted to earth, the pictures were processed by digital computer to remove camera-induced distortions. The removal process was performed by the JPL Image Processing Laboratory (IPL) using calibration data measured during prelaunch testing of the cameras. The Reduced Data Record (RDR) is the set of data which results from the distortion-removal, or decalibration, process. The principal elements of the RDR are numerical data on magnetic tape and photographic data. Numerical data are the result of correcting for geometric and photometric distortions and residual-image effects. Photographic data are reproduced on negative and positive transparency films, strip contact and enlargement prints, and microfiche positive transparency film. The photographic data consist of two versions of each TV frame created by applying two special enhancement processes to the numerical data.

Seidman, J. B.↗
NASA NTRS1973

Mars atmosphere during the Mariner 9 extended mission: Television results

Data from the Mariner 9 extended mission provide a record of seasonally varying processes from mid-spring to early summer in the Northern Hemisphere of Mars. Atmospheric phenomena observed by the television cameras during this period are: (1) A faint shelf of brightness near 20 km in height; (2) condensate clouds over Hellas in the early morning, (3) wave clouds over the south polar region indicating strong west to east winds; (4) faint wave clouds over the north polar cap indicating northeast to southwest flow off the cap; and (5) clouds over the major vocanos and Tithonius Lacus which show remarkable repeatability, strong topographic control, and, in some cases, evidence for convective structure.

Leovy, C. B.↗
NASA NTRS1972

The Martian atmosphere - Mariner 9 television experiment progress report.

Atmospheric phenomena appearing in the Mariner 9 television pictures are discussed in detail. The surface of the planet was heavily obscured by a global dust storm during the first month in orbit. Brightness data during this period can be fitted by a semi-infinite scattering and absorbing atmosphere model with a single-scattering albedo in the range 0.70-0.85. This low value suggests that the mean radius of the particles responsible for the obscuration was at least 10 microns. By the end of the second month, this dust storm had largely dissipated, leaving a residual optical depth of about 0.1. Much of the region north of 45 deg N was covered by variable clouds comprising the north polar hood.

Leovy, C. B.↗
NASA NTRS1972

Apollo 15 and 16 ground-commanded television assembly.

During the Apollo 15 and 16 missions, a special camera provided the scientific community and the home viewer with real-time coverage of the lunar exploration. The lunar blast-off of the Apollo 16 ascent module was tracked by the mission controller at NASA's Manned Space Center and watched 250,000 miles away on earth. The operation of this television camera and the remote control unit are described and block diagrams given. Ground-command capability from the Mission Control Center permitted versatility and optimization of the TV coverage, without diverting the astronauts from their primary role of lunar exploration.

Soltoff, B. M.↗
NASA NTRS1973

Verification of performance of the Mariner 9 television cameras.

The large volume of picture data produced by the Mariner 9 Television Experiment, in addition to providing a description of the planet Mars, emphasizes the need for in situ verification of camera performance. Such data provide the basis for initial quantitative image interpretation by confirmation of the relevance of preflight measurement. This information must be the result of planned calibration sequences rather than extraction from nominal mission photography. A lack of sufficient numbers of frames restricted Mariner camera verifications to only limited operational modes under optimal conditions and required significant extrapolation over the duration of the mission. The evidence does suggest that measurable photometric changes occurred, whereas agreement with preflight data is observed for other parameters.

Thorpe, T. E.↗
NASA NTRS1974

Field-sequential stereo television

System includes viewing devices that provide low interference to normal vision. It provides stereo display observable from broader area. Left and right video cameras are focused on object. Output signals from cameras are time provided by each camera. Multiplexed signal, fed to standard television monitor, displays left and right images of object.

Perry, W. E.↗
NASA NTRS1973

Stratoscope 2 integrating television camera

The development, construction, test and delivery of an integrating television camera for use as the primary data sensor on Flight 9 of Stratoscope 2 is described. The system block diagrams are presented along with the performance data, and definition of the interface of the telescope with the power, telemetry, and communication system.

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NASA NTRS1973

Frequency modulation television analysis: Distortion analysis

Computer simulation is used to calculate the time-domain waveform of standard T-pulse-and-bar test signal distorted in passing through an FM television system. The simulator includes flat or preemphasized systems and requires specification of the RF predetection filter characteristics. The predetection filters are modeled with frequency-symmetric Chebyshev (0.1-db ripple) and Butterworth filters. The computer was used to calculate distorted output signals for sixty-four different specified systems, and the output waveforms are plotted for all sixty-four. Comparison of the plotted graphs indicates that a Chebyshev predetection filter of four poles causes slightly more signal distortion than a corresponding Butterworth filter and the signal distortion increases as the number of poles increases. An increase in the peak deviation also increases signal distortion. Distortion also increases with the addition of preemphasis.

Hodge, W. H.↗
NASA NTRS1973

Frequency modulation television analysis: Threshold impulse analysis

A computer program is developed to calculate the FM threshold impulse rates as a function of the carrier-to-noise ratio for a specified FM system. The system parameters and a vector of 1024 integers, representing the probability density of the modulating voltage, are required as input parameters. The computer program is utilized to calculate threshold impulse rates for twenty-four sets of measured probability data supplied by NASA and for sinusoidal and Gaussian modulating waveforms. As a result of the analysis several conclusions are drawn: (1) The use of preemphasis in an FM television system improves the threshold by reducing the impulse rate. (2) Sinusoidal modulation produces a total impulse rate which is a practical upper bound for the impulse rates of TV signals providing the same peak deviations. (3) As the moment of the FM spectrum about the center frequency of the predetection filter increases, the impulse rate tends to increase. (4) A spectrum having an expected frequency above (below) the center frequency of the predetection filter produces a higher negative (positive) than positive (negative) impulse rate.

Hodge, W. H.↗
NASA NTRS1973

Large space telescope television sensor development

Studies conducted towards the development of space astronomy television sensors are reported. The SEC vidicon tubes being utilized in the development effort are described. The operational characteristics of these tubes are given in tables and charts together with discussions of their significance.

Lowrance, J. L.↗