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At least 1,711 records · Page 95

Development of standardized specifications for silicon solar cells

A space silicon solar cell assembly (cell and coverglass) specification aimed at standardizing the diverse requirements of current cell or assembly specifications was developed. This specification was designed to minimize both the procurement and manufacturing costs for space qualified silicon solar cell assembilies. In addition, an impact analysis estimating the technological and economic effects of employing a standardized space silicon solar cell assembly was performed.

Scott-Monck, J. A.↗

A review of the solar array manufacturing industry costing standards

The solar array manufacturing industry costing standards model is designed to compare the cost of producing solar arrays using alternative manufacturing processes. Constructive criticism of the methodology used is intended to enhance its implementation as a practical design tool. Three main elements of the procedure include workbook format and presentation, theoretical model validity and standard financial parameters.

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Development and evaluation of a set of group delay standards

A set of cable assemblies serving as group delay standards having nominal delays of 15, 30, and 60 nsec are described. Various types of measurements were performed on the cable standards, including impedance, microwave phase shift, RF pulse burst delay, modulation pulsed delay, and envelope phase shift measurements. The results of these tests are given, and various sources of error are discussed, in particular, dispersion and internal reflections.

Otoshi, T. Y.↗

The impact of emission standards on the design of aircraft gas turbine engine combustors

The advent of environmental standards for controlling aircraft gas turbine engine emissions has led to a reevaluation of combustor design techniques. Effective emission control techniques have been identified and a wide spectrum of potential applications for these techniques to existing and advanced engines are being considered. Results from advanced combustor concept evaluations and from fundamental experiments are presented and discussed and comparisons are made with existing EPA emission standards and recommended levels for high altitude cruise. The impact that the advanced low emission concepts may impose on future aircraft engine combustor designs and related engine components is discussed.

Rudey, R. A.↗

Provisional standards of radiation safety of flight personnel and passengers in air transport of the civil aviation

Provisional standards for radiation affecting passenger aircraft are considered. Agencies responsible for seeing that the regulations are enforced are designated while radiation sources and types of radiation are defined. Standard levels of permissible radiation are given and conditions for radiation safety are discussed. Dosimetric equipment on board aircraft is delineated and regulation effective dates are given.

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Preliminary design for a standard 10 sup 7 bit Solid State Memory (SSM)

A modular concept with three separate modules roughly separating bubble domain technology, control logic technology, and power supply technology was employed. These modules were respectively the standard memory module (SMM), the data control unit (DCU), and power supply module (PSM). The storage medium was provided by bubble domain chips organized into memory cells. These cells and the circuitry for parallel data access to the cells make up the SMM. The DCU provides a flexible serial data interface to the SMM. The PSM provides adequate power to enable one DCU and one SMM to operate simultaneously at the maximum data rate. The SSM was designed to handle asynchronous data rates from dc to 1.024 Mbs with a bit error rate less than 1 error in 10 to the eight power bits. Two versions of the SSM, a serial data memory and a dual parallel data memory were specified using the standard modules. The SSM specification includes requirements for radiation hardness, temperature and mechanical environments, dc magnetic field emission and susceptibility, electromagnetic compatibility, and reliability.

Hayes, P. J.↗

Survey report on the state-of-the-art of cryogenic thermometry and signal conditioners and their potential for standardized space hardware

The possibility of standard low temperature detector(s) for use in upcoming cryogenically cooled satellite and Space Shuttle Payloads was investigated. These payloads operate from .3 Kelvin to 300 Kelvin. Standard detectors were selected and matching signal conditioning equipment were specified. This equipment will operate in a spacecraft environment and be compatible with the selected detector, typical spacecraft voltages, typical spacecraft telemetry systems, and the radiation encountered by a typical earth orbiting spacecraft. Work statements to better define and advance detector performance are presented.

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LANDSAT 2 world standard catalog, 1 May - 31 July 1978

Information regarding the availability of LANDSAT imagery processed and input to the data files by the NASA Data Processing Facility is published on a monthly basis. The U.S. Standard Catalog includes imagery covering the continental United States, Alaska and Hawaii. The Non-U.S. Standard Catalog identifies all the remaining coverage. Sections 1 and 2 describe the contents and format for the catalogs and the associated microfilm. Section 3 provides a cross-reference defining the beginning and ending dates for LANDSAT cycles.

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Calibration standards and field instruments for the precision measurement of insolation

The design of a fieldworthy survey instrument based on a developed radiation calibration standard is discussed. The radiometer system, a fieldworthy modification of Pacrad, is an all-weather solar radiometer, and a field test is described which demonstrates the instrument's stability in severe environments over an extended period of time. It is suggested that the instrument may be considered a transfer standard as well as a radiometer. It is hoped that future modifications might reduce the 15-deg view angle and improve the tracking system to eliminate weekly manual declination adjustments.

Reid, M. S.↗

Interpretive computer simulator for the NASA Standard Spacecraft Computer-2 (NSSC-2)

An Interpretive Computer Simulator (ICS) for the NASA Standard Spacecraft Computer-II (NSSC-II) was developed as a code verification and testing tool for the Annular Suspension and Pointing System (ASPS) project. The simulator is written in the higher level language PASCAL and implented on the CDC CYBER series computer system. It is supported by a metal assembler, a linkage loader for the NSSC-II, and a utility library to meet the application requirements. The architectural design of the NSSC-II is that of an IBM System/360 (S/360) and supports all but four instructions of the S/360 standard instruction set. The structural design of the ICS is described with emphasis on the design differences between it and the NSSC-II hardware. The program flow is diagrammed, with the function of each procedure being defined; the instruction implementation is discussed in broad terms; and the instruction timings used in the ICS are listed. An example of the steps required to process an assembly level language program on the ICS is included. The example illustrates the control cards necessary to assemble, load, and execute assembly language code; the sample program to to be executed; the executable load module produced by the loader; and the resulting output produced by the ICS.

Smith, R. S.↗

Performance of preproduction model cesium beam frequency standards for spacecraft applications

A cesium beam frequency standards for spaceflight application on Navigation Development Satellites was designed and fabricated and preliminary testing was completed. The cesium standard evolved from an earlier prototype model launched aboard NTS-2 and the engineering development model to be launched aboard NTS satellites during 1979. A number of design innovations, including a hybrid analog/digital integrator and the replacement of analog filters and phase detectors by clocked digital sampling techniques are discussed. Thermal and thermal-vacuum testing was concluded and test data are presented. Stability data for 10 to 10,000 seconds averaging interval, measured under laboratory conditions, are shown.

Levine, M. W.↗

NASA data system standards

The NASA approach to data systems standardization is described. The major thrust of this activity is to assure effective use of NASA resources. The process by which standards are written, who writes them, and what subjects are covered, is briefly examined.

Byers, R. A.↗

Automated frequency standard stability data reduction

A design using a medium sized computer, a fiber optic communication link, and a desk top computer to reduce data collected at a remote site for analysis of frequency standard tests is described. Data generated at the Interim Frequency Standards Test Facility is collected on magnetic tape, which is then transported to a Sigma 5 computer. An Allan variance (two sample variance) is then calculated. The Allan variance (sigma vs tau) is then written to a data file in the Sigma 5. A fiber optic communication link between the Sigma 5 and a desk top computer was designed to transmit data in the Sigma 5 file to the desk top computer. A program was written for the desk top computer that will automatically access the data file in the Sigma 5, process the data and provide a data plot.

Knapp, L. J.↗

High speed CMOS/SOS standard cell notebook

The NASA/MSFC high speed CMOS/SOS standard cell family, designed to be compatible with the PR2D (Place, Route in 2-Dimensions) automatic layout program, is described. Standard cell data sheets show the logic diagram, the schematic, the truth table, and propagation delays for each logic cell.

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Loran-C plotting program for plotting lines of position on standard charts

A set of programs used to plot Loran C lines of position on any common map or standard aviation sectional chart are given. The Loran C plotting program JRPLOT FORTRAN uses a standard Calcomp compatible plotting subroutine package for the Hewlett-Packard 7203A graphic plotter. The programs are designed to be run on an IBM System 370 computer. A simple add subtract method is used to calculate the lines of position. A description of how to use the program and some methods of operation are given.

Roman, J. P.↗

The operational performance of hydrogen masers in the Deep Space Network (the performance of laboratory reference frequency standards in an operational environment)

Spacecraft navigation to the outer planets (Jupiter and beyond) places very stringent demands upon the performance of frequency and time (F&T) reference standards. The Deep Space Network (DSN) makes use of hydrogen masers as an aid in meeting the routine F&T operational requirements within the 64 m antenna network. Results as of October 1980 indicate the hydrogen masers are performing within the required specifications. Two problem areas are discussed: insufficient control over the environment in which the reference standards reside; and frequency drift.

Ward, S. C.↗

Recent progress in the NASA-Goddard Space Flight Center atomic hydrogen standards program

At NASA Goddard Space Flight Center and through associated contractors, a broad spectrum of work is being carried out to develop improved hydrogen maser frequency standards for field use, improved experimental hydrogen maser frequency standards, and improved frequency and time distribution and measurement systems for hydrogen maser use. Recent progress in the following areas is reported: results on the Nr masers built by the Applied Physics Laboratory of Johns Hopkins University, the development of a low cost hydrogen maser at Goddard Space Flight Center, and work on a low noise phase comparison system and digitally phase locked crystal oscillator called the distribution and measurement system.

Reinhardt, V. S.↗