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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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Electrical connector clamp /bus bar/ gives high contact-surface efficiency for providing a high current to thin wall stainless steel tubing containing hydrogen gas. It uses lead solder film to provide the electrical equivalent of a fusion bond without degrading the grain structure, permitting disassembly and reuse of the components.
SiC/Si diode pair provides automatic range change to extend the operating range of a logarithmic amplifier-conversion circuit and assures stability at or near the range switch-over point. the diode provides hysteresis for a trigger circuit that actuates a relay at the desired range extension point.
Eutectic fuses provide current and thermal protection to an electronic system and maintain this protection under high vibration environments. The fuses are embedded within heat shrinkable sleeving which provides positive closing action under the conditions of high current or temperature.
Lightweight battery-package provides for even cooling of individual alkaline cells, constraint against cell expansion, and convenient placement of cells. The battery package also provides for venting of the cells and includes instrumentation to measure cell temperature, pressure, and voltage.
A low power, small size electromagnetic flowmeter system is described which produces a zero output signal for zero flow. The system comprises an air core type electromagnetic flow transducer, a field current supply circuit for the transducer coils and a pre-amplifier and demodulation circuit connected to the output of the transducer. To prevent spurious signals at zero flow, separate, isolated power supplies are provided for the two circuits. The demodulator includes a pair of synchronous rectifiers which are controlled by signals from the field current supply circuit. Pulse transformer connected in front of the synchronous rectifiers provide isolation between the two circuits.
A mass spectrometer (MS) with unique magnetic pole pieces which provide a homogenous magnetic field across the gap of the MS magnetic sector as well as the magnetic field across an ion-type vacuum pump is disclosed. The pole pieces form the top and bottom sides of a housing. The housing is positioned so that portions of the pole pieces form part of the magnetic sector with the space between them defining the gap region of the magnetic sector, through which an ion beam passes. The pole pieces extend beyond the magnetic sector with the space between them being large enough to accommodate the electrical parts of an ion-type vacuum pump. The pole pieces which provide the magnetic field for the pump, together with the housing form the vacuum pump enclosure or housing.
The Mount Agung volcanic eruption in 1963 provides the best-documented global radiative perturbation to the earth's atmosphere currently available. Data on stratospheric aerosols produced by this eruption have been used as input to a model for the atmospheric thermal structure. The computed magnitude, sign, and phase lag of the temperature changes in both the stratosphere and the troposphere are in good agreement with observations, providing evidence that the climatic response to a global radiative perturbation is significant as well as support for the use of theoretical models to predict climatic effects.
A system of orbiting reflectors, SOLARES, has been studied as a possible means of providing terrestrial power with a space system of minimum mass and complexity. The key impact that such a system, providing continuous and slightly concentrated insolation, makes on the economic viability of solar farming is demonstrated. New developments in solar sailing are incorporated to reduce mirror mass and transportation cost. The system is compatible with incremental implementation and continual expansion to produce the world's power needs. Key technology, environmental, and economic issues and payoffs are identified. SOLARES appears to be economically superior to other advanced, and even conventional, energy systems and could be scaled to completely abate our fossil fuel usage for power generation.
The present scheme for providing system timing for the airborne oceanographic lidar (AOL) system is not completely satisfactory. The possibility of using a digital approach to generate the forty pulses needed to energize the gates leading to the charge digitizers was investigated. The solution in terms of general analog and digital circuitry is straightforward. The crystal oscillator provides a stable frequency source which is used as a clock to the ring counter. The ring counter propagates a pulse from stage one to stage forty. Each of the outputs has an amplifier for isolation. This design is easy to implement in the frequency range up to 50 MHZ. Because a gate pulse width of from about 2 to 6 ns is needed for the AOL system, this dictates an input clock frequency to the shift register of from 100 MHA to 500 MHA. Problems associated with generating pulses in this range of operation are examined and an alternate solution is discussed.
It is demonstrated that the analysis in both intensity and polarization of equivalent widths of strong Venusian absorption lines can provide the most accurate location of the visible cloud top as well as the ratios of scale heights of CO2 to cloud particles and CO (or other appropriate minor constituent) to CO2. It is also shown that spectropolarimetric observations at different phase angles can provide a vertical sounding of the upper levels in the cloud. Equivalent widths in polarization are measurable on Venus with good infrared detectors, and their value is predicted to be approximately a few percent of those in intensity.
The Aerospace Ground Equipment (AGE) provides an interface between a human operator and a complete spaceborne sequence timing device with a memory storage program. The AGE provides a means for composing, editing, syntax checking, and storing timing device programs. The AGE is implemented with a standard Hewlett-Packard 2649A terminal system and a minimum of special hardware. The terminal's dual tape interface is used to store timing device programs and to read in special AGE operating system software. To compose a new program for the timing device the keyboard is used to fill in a form displayed on the screen.
The Satellite Resources Management and Tracking System was developed specifically for the Hubble Space Telescope (HST) program, and now, NASA has the ability to immediately access the necessary data for planning successful orbital satellite servicing operations. This system is an online, real-time data base system that contains a plethora of data on each item identified to support the HST throughout its planned 15 year life. Some of the information provided includes the current status, location, quantity, and history of each asset, a separate record for each discrete serial numbered item, procurement lead times on items sensitive to technology obsolescence, and the maintenance and repair history of each asset. Finally, details are provided on organizational, operational and logistics requirements.
The authors of this paper have provided a set of ready-to-run FORTRAN programs that should be useful in the field of theoretical nuclear physics. The purpose of this document is to provide a simple synopsis of the programs and their use. A separate section is devoted to each program set and includes: abstract; files; compiling, linking, and running; obtaining results; and a tutorial.
A strip imaging wide angle optical system is provided. The optical system is provided with a 'virtual' material stop to avoid aberrational effects inherent in wide angle optical systems. The optical system includes a spherical mirror section for receiving light from a 180 deg strip or arc of a target image. Light received by the spherical mirror section is reflected to a frustoconical mirror section for subsequent rereflection to a row of optical fibers. Each optical fiber transmits a portion of the received light to a detector. The optical system exploits the narrow cone of acceptance associated with optical fibers to substantially eliminate vignetting effects inherent in wide angle systems. Further, the optical system exploits the narrow cone of acceptance of the optical fibers to substantially limit spherical aberration. The optical system is ideally suited for any application wherein a 180 deg strip image need be detected, and is particularly well adapted for use in hostile environments such as in planetary exploration.
This paper describes the implementation of the ground network to support Mobile Satellite Services (MSS). The system is designed to take advantage of a powerful new satellite series and provides significant improvements in capacity and throughput over systems in service today. The system is described in terms of the services provided and the system architecture being implemented to deliver those services. The system operation is described including examples of a circuit switched and packet switched call placement. The physical architecture is presented showing the major hardware components and software functionality placement within the hardware.
The National Space Science Data Center (NSSDC) is making a growing fraction of its most customer-desirable data electronically accessible via both the local and wide area networks. NSSDC is witnessing a great increase in its data dissemination owing to this network accessibility. To provide its customers the best data accessibility, the NSSDC makes data available from a nearline, mass storage system, the NSSDC Data Archive and Dissemination Service (NDADS). The NDADS, the initial version was made available in January 1992, is a customized system of hardware and software that provides users access to the nearline data via ANONYMOUS FTP, an e-mail interface (ARMS), and a C-based software library. In January 1992, the NDADS registered 416 requests for 1,957 files. By December of 1994, NDADS had been populated with 800 gigabytes of electronically accessible data and had registered 1458 requests for 20,887 files. In this report we describe the NDADS system, both hardware and software. Later in the report, we discuss some of the lessons that were learned as a result of operating NDADS, particularly in the area of ingest and dissemination.
By the end of this decade, Hughes' SPACEWAY network will provide the first interactive 'bandwidth on demand' communication services for a variety of applications. High quality digital voice, interactive video, global access to multimedia databases, and transborder workgroup computing will make SPACEWAY an essential component of the computer-based workplace of the 21st century. With relatively few satellites to construct, insure, and launch -- plus extensive use of cost-effective, tightly focused spot beams on the world's most populated areas -- the high capacity SPACEWAY system can pass its significant cost savings onto its customers. The SPACEWAY network is different from other proposed global networks in that its geostationary orbit location makes it a truly market driven system: each satellite will make available extensive telecom services to hundreds of millions of people within the continuous view of that satellite, providing immediate capacity within a specific region of the world.
This paper presents a summary description of SPACEWAY(TM), a network of Ka band geostationary satellites being developed by Hughes Communications, Inc. to provide worldwide interactive telecommunications services to small, low cost user terminals. By the end of this decade SPACEWAY(TM), using relatively few satellites and tightly focused spot beams, will provide affordable interactive 'bandwidth on demand' communication services on a global basis to consumer and commercial end users. This paper describes the system concept, details the space and ground segment characteristics, and discusses communication links.