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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 739 records · Page 41
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

A series-resonant silicon-controlled-rectifier power processor for ion thrusters

A program to develop a power processing system for ion thrusters is presented. Basic operation of the silicon controlled rectifier series inverter circuitry is examined. The approach for synthesizing such circuits into a system which limits the electrical stress levels on the power source, semiconductor switching elements, and the ion thruster load is described. Experimental results are presented for a 2.5-kW breadboard system designed to operate a 20-cm ion thruster.

Shumaker, H. A.↗
NASA NTRS1972

Design concepts for an on-board coherent optical image processor

On-board spacecraft image data processing systems for transmitting processed data rather than raw data are discussed. A brief history of the development of the optical data processing techniques is presented along with the conceptual design of a coherent optical system with a noncoherent image input.

Husain-Abidi, A. S.↗
NASA NTRS1972

Feasibility investigation of a cellularly organized data processor

The application of cellular arrays to NASA missions was studied. Cellular arrays are iterative logical and memory structures which can be programmed to accomplish a wide variety of logical tasks. Used in long-duration space missions, spare cellular arrays can be remotely programmed to replace faulty logical subsystems as the need arises.

Minnick, R. C.↗
NASA NTRS1973

The data processor from the small scientific satellite

A reprogrammable data system aboard a small scientific satellite is described that samples and processes magnetospheric measurements for transmission to the ground. The lightweight configuration of the data system is made up of the program memory, data storage, input/output module, and a central processing unit. The system is designed for multiple missions.

Mccain, H. G.↗
NASA NTRS1973

Single step detection of blurred images in a coherent optical processor.

Two important operations that can be performed by coherent optical processing systems are image detection and image restoration. These operations require complex spatial filters, and if both operations are to be performed, cascaded processing stages employing two separate spatial filters are usually needed. Spatial filters are described that will perform in a single step both operations simultaneously, thus eliminating the need for extra processing stages while providing the advantages of higher efficiency and smaller space requirements. The filters are characterized by their simplicity and are easily fabricated using conventional techniques. Experimental results are presented.

Jablonowski, D. P.↗
NASA NTRS1973

A 30-cm thruster power processor test console

The development of a high performance ion propulsion system composed of an ion thruster and its associated power processing equipment, dictates the establishment of a mutually compatible set of electrical characteristics. A 30-cm thruster power processing console has been developed which utilizes power and control circuitry applicable to flight hardware designs, incorporates interface circuitry for optional direct computer control, and has self-contained instrumentation for assessing steady-state and dynamic system behavior. This paper discusses the console's design, utility, performance, and the potential impact of this development effort on future hardware designs.

Herron, B. G.↗
NASA NTRS1974

Development of a Korotkov sound processor for automatic identification of auscultatory events. I - Specification of preprocessing bandpass filters

Frequency bands that best discriminate the Korotkov sounds at systole and at diastole from the sounds immediately preceding these events are defined. Korotkov sound data were recorded from five normotensive subjects during orthostatic stress (lower body negative pressure) and bicycle ergometry. A spectral analysis of the seven Korotkov sounds centered about the systolic and diastolic auscultatory events revealed that a maximum increase in amplitude at the systolic transition occurred in the 18-26-Hz band, while a maximum decrease in amplitude at the diastolic transition occurred in the 40-60-Hz band. These findings were remarkably consistent across subjects and test conditions. These passbands are included in the design specifications for an automatic blood pressure measuring system used in conjuction with medical experiments during NASA's Skylab program.

Golden, D. P., Jr.↗
NASA NTRS1974

Shuttle extravehicular activity signal processor pulse amplitude modulation decommutator

To provide data with long-term stability and accuracy, the pulse amplitude modulation (PAM) decommutator was synchronized to the PAM-return to zero wavetrain, and each channel was sampled with a common sample and hold circuit and digitized sequentially. The digital value of each channel was then scaled by the digital value of the calibration channels. The corrected digital value of each channel was stored for one complete frame and then transferred to the multiplexer-demultiplexer at a high rate in one block of serial digital data. A test model was built to demonstrate this design approach taken for the PAM decom and performance data was provided. The accuracies obtained with various signal to noise ratios are shown.

Noble, D. E.↗
NASA NTRS1975

Processor architectures utilizing magnetic bubble and semi-conductor memories

To aid work being conducted on the feasibility of a low cost Omega navigational receiver, a control panel was designed and constructed according to supplied specifications. Since the proposed Omega receiver is designed around a microprocessor, software engineering necessary for control panel operation is included in the design. The control panel is to be used as an operational model for use in the design of a prototype receiver. A detailed description of the hardware design is presented along with a description of the software needed to operate the panel. A complete description of the operating procedures for the panel are also included.

Parrish, E. A., Jr.↗
NASA NTRS1975

Instruction manual, optical effects module electronic controller and processor, model OEMCP

The OEM-1 electronic module is discussed; it is comprised of four subsystems: the signal processing and display; the stepper motor controls; the chopper controls; and the dc-dc invertor. The OEM-1 module controls the sample wheel so that the relative transmittance of the samples can be compared to the clear aperture position. The 3-1/2 digit digital voltmeter displays the clear aperture signal level as well as the ratio of the remaining sample positions relative to the clear aperture position. The sample wheel position is decoded so that the signals and ratios can be correlated to the data. The OEM is automatically reset to the I sub o on initial turn-on and can be reset to the '0' position by actuating a front panel switch. The sample wheel can be interrupted to change samples or induce a longer integration time if desired by a front panel command. Integration times from 1 - 50 seconds are provided at the front panel, and BCD data for external interfacing is provided.

Source record↗
NASA NTRS1975

Specification and preliminary design of an array processor

The design of a computer suited to the class of problems typified by the general circulation of the atmosphere was investigated. A fundamental goal was that the resulting machine should have roughly 100 times the computing capability of an IBM 360/95 computer. A second requirement was that the machine should be programmable in a higher level language similar to FORTRAN. Moreover, the new machine would have to be compatible with the IBM 360/95 since the IBM machine would continue to be used for pre- and post-processing. A third constraint was that the cost of the new machine was to be significantly less than that of other extant machines of similar computing capability, such as the ILLIAC IV and CDC STAR. A final constraint was that it should be feasible to fabricate a complete system and put it in operation by early 1978. Although these objectives were generally met, considerable work remains to be done on the routing system.

Slotnick, D. L.↗
NASA NTRS1975

Application of a dedicated micro-processor for automatic data acquisition of load strain and acoustic-emission data

This paper describes an automatic system for acquisition, logging and analysis of stress, strain and acoustic emission data. The complete system is a combination of several standard items of equipment and a newly developed intelligent data logger which has the capability to send data directly to a large scale computer for reduction and plotting. The data logging and all interfacing with peripheral equipment are accomplished using digital electronics. The heart of the system is a four-bit microprocessor and digital cassette tape unit. The system, which is controlled by instructions from a cathode ray tube terminal, has the capability to transmit data from the cassette unit to a large computer via a time sharing option. Typical results are presented for acoustic emission count rate and total count curves superimposed on stress-strain diagrams for boron/epoxy advanced composites.

Wilson, G. H.↗