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A video tape recorder is disclosed of sufficient bandwidth to record monochrome television signals or standard NTSC field sequential color at current European and American standards. The system includes scan conversion means for instantaneous playback at scanning standards different from those at which the recording is being made.
From video-tape recordings of lightning flashes to ground in convective daytime storms at the NASA Kennedy Space Center, Florida, and near Ocala, Florida, statistical data are presented for the flash-time duration, the number of strokes per flash, the time between all strokes, and the time between strokes having spatially separate channels. A daytime video tape 'photograph' of a stepped leader is reproduced. Finally, statistical data are presented for 13 long horizontal lightning discharges occurring along a line of nocturnal thunderstorms near Gainesville, Florida. These discharges all propagated horizontally near the freezing level (4.5 km) at an apparent average velocity between 5600 and 11,000 m/s for a typical distance of 2 to 3 km. Eleven of the 13 horizontal discharges were preceded by or occurred within 16.7 ms of a glow in the cloud roughly 0.5 km above the horizontal channel.
The chemistry of the cometary meteoroids was studied by closed circuit television observing systems. Vidicon cameras produce basic data on standard video tape and enable the recording of the spectra of faint shower meteors, consequently the chemical study is extended to smaller particles and we have a larger data bank than is available from the more conventional method of recording meteor spectra by photography. The two main problems in using video tape meteor spectrum records are: (1) the video tape recording has a much lower resolution than the photographic technique; (2) video tape is relatively new type of data storage in astronomy and the methods of quantitative photometry have not yet been fully developed in the various fields where video tape is used. The use of the most detailed photographic meteor spectra to calibrate the video tape records and to make positive identification of the more prominent chemical elements appearing in the spectra may solve the low resolution problem. Progress in the development of standard photometric techniques for the analysis of video tape records of meteor spectra is reported.
An analysis of video tapes of nocturnal lightning events, taken aboard space shuttle flights STS-8, STS-9, STS-41D, and STS-51J, shows flashes with dimensions ranging from approximately 1 km by 1 km to 440 km by 110 km. Of particular interest are the flashes whose dimensions exceeded 100 km, as flashes of this size are seldom reported. In general, larger flashes were found to have longer durations, take longer to reach their maximum extent, and reach their maximum extent at a smaller percent of their total duration than smaller flashes. Sixty four percent of the flashes occurred with one to five other events appearing in the same video frame. These simultaneous events were an average of 60 km apart from each other. If a breakdown process is propagating between the simultaneous flashes, it would be travelling at a rate of 10(exp 5)m/sec. Plots of the area of an event over its duration show peaks in the area curve which may be indicative if lightning strokes. There was an average of 3.6 peaks per flash. In general, the longer the flash duration, the more peaks there were in the area curve. The area curves of the lightning events fall into one of five shape categories. It is suggested that the shape of the area curve may indicate whether an event is an intracloud or cloud to ground lightning flash. Some of the lightning events had a persistent bright spot. These events had an average duration which was greater than that of events without the bright spot. On average, the bright spot events had a maximum area which was larger than that of the flashes without the bright spot.
Photometric reduction of Lunar Orbiter video magnetic tapes for generation of topographic information of proposed Apollo landing sites
Standards and controls are established for the procurement of wide channel bandwidth one inch video magnetic recording tapes for Very Long Base Interferometer (VLBI) system applications. The Magnetic Tape Certification Facility (MTCF) currently maintains three specifications for the Quality Products List (QPL) and acceptance testing of magnetic tapes. NASA-TM-79724 is used for the QPL and acceptance testing of new analog tapes; NASA-TM-80599 is used for QPL and acceptance testing of new digital tapes; and NASA-TM-100702 is used for the QPL and acceptance testing of new IBM/IBM compatible 3480 magnetic tape cartridges. This specification will be used for the QPL and acceptance testing of new wide channel bandwidth one inch video magnetic recording tapes. The one inch video tapes used by the Jet Propulsion Lab., the Deep Space Network and the Haystack Observatory will be covered by this specification. These NASA stations will use the video tapes for their VLBI system applications. The VLBI system is used for the tracking of quasars and the support of interplanetary exploration.
Fatigue-crack initiation and early stages of growth in notched 2024-T3 aluminum alloy sheet specimens were monitored during constant-amplitude fatigue tests conducted for a range of stress ratios. A video tape system was developed to detect fatigue cracks 0.1 mm in length on the sheet surface and to monitor their growth. Fatigue cracks initiated either at the notch corner or on the notch surface. Most of the first fatigue cracks started as notch-corner cracks, and the crack-initiation period was defined as the number of cycles for which the crack was 0.1 mm in length on the sheet surface. For each of the stress ratios used, the results showed that at the low stress levels, the crack-initiation period constituted at least 90 percent of the fatigue lives. However, for the negative stress ratios at the high stress levels, cracks started as early as at about 40 percent of the fatigue lives.
A descriptive handbook for the CTE splitter (RCA part No. 8673734-503) was presented. This unit is designed to extract time data from an interleaved video audio signal. It is a rack mounting unit 7 inches high, 19 inches wide, 20 inches deep, mounted on slides for retracting from the rack, and weighs approximately 40 pounds. The following information is provided: installation, operation, principles of operation, maintenance, schematics and parts lists.
A descriptive handbook for the audio/CTE splitter/interleaver (RCA part No. 8673734-502) was presented. This unit is designed to perform two major functions: extract audio and time data from an interleaved video/audio signal (splitter section), and provide a test interleaved video/audio/CTE signal for the system (interleaver section). It is a rack mounting unit 7 inches high, 19 inches wide, 20 inches deep, mounted on slides for retracting from the rack, and weighs approximately 40 pounds. The following information is provided: installation, operation, principles of operation, maintenance, schematics and parts lists.
A descriptive handbook for the CTE splitter (RCA part No. 8673734-50A) was presented. This unit is designed to extract time data from an interleaved video/audio signal. It is a rack mounting unit 7 inches high, 19 inches wide, 20 inches deep, mounted on slides for retracting from the rack, and weighs approximately 40 pounds. The following information is provided: installation, operation, principles of operation, maintenance, schematics and parts lists.
Six professionally active, retired captains rated the coordination and decisionmaking performances of sixteen aircrews while viewing videotapes of a simulated commercial air transport operation. The scenario featured a required diversion and a probable minimum fuel situation. Seven point Likert-type scales were used in rating variables on the basis of a model of crew coordination and decisionmaking. The variables were based on concepts of, for example, decision difficulty, efficiency, and outcome quality; and leader-subordin ate concepts such as person and task-oriented leader behavior, and competency motivation of subordinate crewmembers. Five-front-end variables of the model were in turn dependent variables for a hierarchical regression procedure. The variance in safety performance was explained 46%, by decision efficiency, command reversal, and decision quality. The variance of decision quality, an alternative substantive dependent variable to safety performance, was explained 60% by decision efficiency and the captain's quality of within-crew communications. The variance of decision efficiency, crew coordination, and command reversal were in turn explained 78%, 80%, and 60% by small numbers of preceding independent variables. A principle component, varimax factor analysis supported the model structure suggested by regression analyses.
Mr. Aldo Bordano will be presenting details of some of the JSC flight mechanics involvement in the X-38 testing program. Focus shall be on the parafoil system with regards its testing, performance analysis, and GN&C. An excellent example of a recent flight test at Dryden Flight Research Center shall be shown which portrays the system characteristics, sequencing, performance, and testing techniques. The intent is to inform the scientific and engineering communities about the developments in the X-38 parafoil program, as well as invite feedback on potential improvements in testing or systems.
A remote sensing oculometer has been successfully operated during flight tests. This device was able to track the pilot's eye-point-of-regard (lookpoint) consistently and unobtrusively in the flight environment. The instantaneous position of the lookpoint was determined to within approximately 1 degree. Data were recorded on both analog and video tape. The video data consisted of continuous scenes of the aircraft's instrument display and a superimposed white dot (simulating the lookpoint) dwelling or moving from instrument to instrument as the pilot monitored the display information during landing approaches.
A remote sensing oculometer was successfully operated during flight tests with a NASA experimental Twin Otter aircraft at the Langley Research Center. Although the oculometer was designed primarily for the laboratory, it was able to track the pilot's eye-point-of-regard (lookpoint) consistently and unobtrusively in the flight environment. The instantaneous position of the lookpoint was determined to within approximately 1 deg. Data were recorded on both analog and video tape. The video data consisted of continuous scenes of the aircraft's instrument display and a superimposed white dot (simulating the lookpoint) dwelling on an instrument or moving from instrument to instrument as the pilot monitored the display information during landing approaches.
Angiographic experiments were performed on isolated canine left ventricle preparations using donor dog to supply blood to the coronary circulation via a rotary pump to control coronary flow. The angiographic record was transferred from video tape to video disk for detailed uninterrupted sequential analysis at a frequency of 60 fields/sec. It is shown that the use of a biplane X-ray technique and a metabolically supported isolated canine left ventricle preparation provides an angiographically ideal means of measuring the mechanical dynamics of the myocardium while the intact left ventricular myocardial structure and electrical activation pattern retain most of the in situ ventricular characteristics. In particular, biplane X-ray angiography of the left ventricle can provide estimates of total ventricular function such as ejection fraction, stroke volume, and myocardial mass correct to within 15% under the angiographically ideal conditions of the preparation.
The general nature of meteor spectra and the major meteor streams that are well represented in the currently available meteor spectra data bank are examined. Attention is given to resolution in meteor spectra obtainable with photographic and video-tape data, heights and velocities, and chemical abundances. The discussion also covers the use of photometric techniques for the determination of absolute luminosities in the spectrum lines of video-tape data. A procedure for the photometric calibration of digitized video-tape records is discussed.
Metal particulate (MP) video tape was launched for 8 mm video tape in 1985. Since then MP tapes have been applied to several consumer formats and instrumental formats because of its superior electrical performance. Recently data storage media, such as DDS and D-8, have started employing MP tape. However, there are serious concerns with archival stability of MP tape particularly in the case of data storage use, as metal particles essentially have problems with chemical instability and are susceptible to oxidation and corrosion. Although there were some studies about the archival stability of metal particles or MP tapes, a clear understanding has yet to be reached. In this paper, we report the stability of magnetic properties of current metal particles, and then discuss the new technologies to improve the stability further.
High performance graphics workstations are used to visualize the fluid flow dynamics obtained from supercomputer solutions of computational fluid dynamic programs. The visualizations can be done independently on the workstation or while the workstation is connected to the supercomputer in a distributed computing mode. In the distributed mode, the supercomputer interactively performs the computationally intensive graphics rendering tasks while the workstation performs the viewing tasks. A major advantage of the workstations is that the viewers can interactively change their viewing position while watching the dynamics of the flow fields. An overview of the computer hardware and software required to create these displays is presented. For complex scenes the workstation cannot create the displays fast enough for good motion analysis. For these cases, the animation sequences are recorded on video tape or 16 mm film a frame at a time and played back at the desired speed. The additional software and hardware required to create these video tapes or 16 mm movies are also described. Photographs illustrating current visualization techniques are discussed. Examples of the use of the workstations for flow visualization through animation are available on video tape.