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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 1,351 records · Page 75
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Silicon solar cells by ion implantation and pulsed energy processing

A new method for fabrication of silicon solar cells is being developed around ion implantation in conjunction with pulsed electron beam techniques to replace conventional furnace processing. Solar cells can be fabricated totally in a vacuum environment at room temperature. Cells with 10% AM0 efficiency have been demonstrated. High efficiency cells and effective automated processing capabilities are anticipated.

Kirkpatrick, A. R.↗
NASA NTRS1978

Development of an improved high efficiency thin silicon solar cell

Efforts were directed towards investigating means of producing more effective high-low junctions at the back of the cell. Cells with output power up to 77 mW (AM0 efficiency of 14.2 percent) were fabricated. Some reflectivity studies were also made. Deliveries of 2 cm x 2 cm experimental cells included a number having AM0 outputs greater than 70 mW.

Wrigley, C.↗
NASA NTRS1981

The development of an 85-kW (thermal) steam Rankine solar receiver

The receiver is a once-through monotube boiler designed for steam/electric and process steam applications at pressures up to 17.24 MPa (2500 psia) and temperatures up to 704 C (1300 F). The unit is 76.2 cm (30.0 in.) in diameter and 95.8 cm (37.7 in.) in length; it weighs 220 kg (485 lb). Its heat transfer surface, which is 45.7 cm (18 in.) in diameter by 57 cm (22.4 in.) long, is an Inconel 625, cylindrical, tube-coil assembly composed of primary and reheat sections. A test unit was successfully operated at up to 6.9 MPa (1000 psia) and 704 C (1300 F) with solar input from a 11-m-dia parabolic dish concentrator.

Wright, C. C.↗
NASA NTRS1982

New component development for multi-100 kW low-cost solar array applications

Studies of the cost and performance of flexible arrays have shown that the most dramatic reductions in the $/Watt figure of merit are achieved by increasing performance. An examination of those properties that contribute to array performance indicated areas where radical changes in current design practice and philosophy would result in significant cost and performance impacts. To take advantage of the predicted cost reductions, modules were fabricated and tested that had ultra-thin superstrates as a load carrying member and large area dielectric wraparound (DWA), gridded back surface and copper contacted solar cells.

Pack, G. J.↗
NASA NTRS1993

Development, refinement, and testing of a short term solar flare prediction algorithm

Progress toward performance of the tasks and accomplishing the goals set forth in the two year Research Grant included primarily analysis of digital data sets and determination of methodology associated with the analysis of the very large, unique, and complex collection of digital solar magnetic field data. The treatment of each magnetogram as a unique set of data requiring special treatment was found to be necessary. It is determined that a person familiar with the data, the analysis system, and logical, coherent outcome of the analysis must conduct each analysis, and interact with the analysis program(s) significantly sometimes many iterations for successful calibration and analysis of the data set. With this interaction, the data sets yield valuable, coherent analyses. During this period, it was also decided that only data sets taken inside heliographic longitudes (Central Meridian Distance) East and West 30 degrees (within 30 degrees of the Central Meridian of the Sun). If the total data set is then found to be numerically inadequate for the final analysis, 30 - 45 degrees Central Meridian Distance data will then be analyzed. The Optical Data storage system (MSFC observatory) was found appropriate for use both in intermediate storage of the data (preliminary to analysis), and for storage of the analyzed data sets for later parametric extraction.

Smith, Jesse B., Jr.↗
NASA NTRS1994

The development of an Infrared Environmental System for TOPEX Solar Panel Testing

Environmental testing and flight qualification of the TOPEX/POSEIDON spacecraft solar panels were performed with infrared (IR) lamps and a control system that were newly designed and integrated. The basic goal was more rigorous testing of the costly panels' new composite-structure design without jeopardizing their safety. The technique greatly reduces the costs and high risks of testing flight solar panels.

environmental simulation solar panel thermal testi↗
NASA NTRS2010

Gimbals Drive and Control Electronics Design, Development and Testing of the LRO High Gain Antenna and Solar Array Systems

Launched June 18, 2009 on an Atlas V rocket, NASA's Lunar Reconnaissance Orbiter (LRO) is the first step in NASA's Vision for Space Exploration program and for a human return to the Moon. The spacecraft (SC) carries a wide variety of scientific instruments and provides an extraordinary opportunity to study the lunar landscape at resolutions and over time scales never achieved before. The spacecraft systems are designed to enable achievement of LRO's mission requirements. To that end, LRO's mechanical system employed two two-axis gimbal assemblies used to drive the deployment and articulation of the Solar Array System (SAS) and the High Gain Antenna System (HGAS). This paper describes the design, development, integration, and testing of Gimbal Control Electronics (GCE) and Actuators for both the HGAS and SAS systems, as well as flight testing during the on-orbit commissioning phase and lessons learned.

Chernyakov, Boris↗
NASA NTRS1982

An investigation of quasi-inertial attitude control for a solar power satellite

An efficient means, a quasi-inertial attitude mode, is developed for maintaining the normal solar orientation of a space satellite for power collection in a synchronous orbit. Formulae are presented which establish the basic parametric properties for ideal quasi-inertial attitude and phasing. An active control system is necessary to compensate for the energy loss since energy dissipation in widely oscillating flexible bodies produces an instability of the quasi-inertial attitude in the sense that the spacecraft will tumble at the orbit rate. A fixed terminal time and state optimal control problem is formulated and an algorithm for determining the optimal control as a means for the periodical attitude and phase compensation is developed. The vehicle orientation affected by internal disturbance (structural flexibility) and external disturbances (e.g., drag forces) is maintained by a specialized controller design.

Juang, J.-N.↗
NASA NTRS1995

Catalog of solar wind events identified from observations by ISTP spacecraft

The ISTP Science Planning and Operations Facility (SPOF), in collaboration with ISTP investigators, is developing a catalog of solar wind events and features. The catalog is primarily based on plasma and magnetic field observations from the WIND and IMP-8 spacecraft. Interplanetary events that may trigger magnetospheric activity are included as well as features of interest for using the solar wind as a plasma laboratory. Catalog coverage begins on September 8, 1992, the start of ISTP science data collection. The catalog is based on Key Parameter data sets (preliminary summary data at approximately 1 min time resolution produced quickly for survey purposes) and as such has limited citability in formal scientific work. Its primary intent is to serve as a reference for identifying candidate periods for further study, such as may be the focus of coordinated data analysis efforts during ISTP and/or IACG Science Campaigns. To facilitate access by members of the ISTP and wider space physics communities, the catalog will be available on the World Wide Web. The contents of the catalog will be described, and samples of catalog information will be presented.

Peredo, M.↗
NASA NTRS1975

On presupernova dynamical mass ejection by non-detonated stellar cores

Stars in the range of 4 to 8 solar masses are known to develop degenerate carbon-oxygen cores of about 1.4 solar masses. Arguments are presented why, contrary to past assumption, carbon ignition may not lead to the formation of a detonation wave. Rather, an initially subsonic burning front results which subsequently may be brought under control by adiabatic expansion. This dynamic phase leads to a centrally incinerated and expanded core. The loosely bound red-giant envelope is ejected to form an extended nebula. Neutrino cooling of the core finally induces collapse. Provided that sufficient energy is liberated in the dynamic formation of a neutron star, a supernova event will result. The distended nebula is ideally suited for the production of the visible supernova light curves. Thus, carbon nondetonation may give a viable alternative evolution to supernovae that avoids the impasse encountered by the detonation-disrupted models.

Buchler, J.-R.↗
NASA NTRS2002

Progress in the Development of Metamorphic Multi-Junction III-V Space-Solar Cells at Essential Research Incorporated

Theoretical calculations have shown that highest efficiency III-V multi-junction solar cells require alloy structures that cannot be grown on a lattice-matched substrate. Ever since the first demonstration of high efficiency metamorphic single junction 1.1 eV and 1.2 eV InGaAs solar cells by Essential Research Incorporated (ERI), interest has grown in the development of multi-junction cells of this type using graded buffer layer technology. ERI is currently developing a dual-junction 1.6 eV InGaP/1.1 eV InGaAs tandem cell (projected practical air-mass zero (AM0), one-sun efficiency of 28%, and 100-sun efficiency of 37.5%) under a Ballistic Missile Defense Command (BMDO) SBIR Phase II program. A second ongoing research effort at ERI involves the development of a 2.1 eV AlGaInP/1.6 eV InGaAsP/1.2 eV InGaAs triple-junction concentrator tandem cell (projected practical AM0 efficiency of 36.5% under 100 suns) under a SBIR Phase II program funded by the Air Force. We are in the process of optimizing the dual-junction cell performance. In case of the triple-junction cell, we have developed the bottom and the middle cell, and are in the process of developing the layer structures needed for the top cell. A progress report is presented in this paper.

Sinharoy, Samar↗
NASA NTRS1986

Characterization of solar-grade silicon produced by the SiF4-Na process

A process was developed for producing low cost solar grade silicon by the reaction between SiF4 gas and sodium metal. The results of the characterization of the silicon are presented. These results include impurity levels, electronic properties of the silicon after crystal growth, and the performance of solar photovoltaic cells fabricated from wafers of the single crystals. The efficiency of the solar cells fabricated from semiconductor silicon and SiF4-Na silicon was the same.

Sanjurjo, A.↗
NASA NTRS1976

Definition study for photovoltaic residential prototype system

A parametric sensitivity study and definition of the conceptual design is presented. A computer program containing the solar irradiance, solar array, and energy balance models was developed to determine the sensitivities of solar insolation and the corresponding solar array output at five sites selected for this study as well as the performance of several solar array/battery systems. A baseline electrical configuration was chosen, and three design options were recommended. The study indicates that the most sensitive parameters are the solar insolation and the inverter efficiency. The baseline PST selected is comprised of a 133 sg m solar array, 250 ampere hour battery, one to three inverters, and a full shunt regulator to limit the upper solar array voltage. A minicomputer controlled system is recommended to provide the overall control, display, and data acquisition requirements. Architectural renderings of two photovoltaic residential concepts, one above ground and the other underground, are presented. The institutional problems were defined in the areas of legal liabilities during and after installation of the PST, labor practices, building restrictions and architectural guides, and land use.

Imamura, M. S.↗
NASA NTRS1979

A method of predictions geomagnetic activity based on a coronal model of relations between solar and geomagnetic activities

A method developed to predict both disturbed and quiet geomagnetic periods is described. The method uses solar situations along the CM with the key role of filaments, giving indirect evidence of types of directly unobservable coronal structures above them. The time lag, not to be interpreted in terms of propagation speed, between the CM activity and the commencement of the geomagnetic response is about one to two days. Solar phenomena serve as indicators within approximately 10 deg of the CM and up to the zone of high latitude filaments.

Halenka, J.↗
NASA NTRS1980

Recent progress in high-output-voltage silicon solar cells

The status of the technology associated with the development of high output voltage silicon solar cells is reported. The energy conversion efficiency of a double diffusion process is compared to that of a single diffusion process. The efficiency of a 0.1 ohm/cm solar cell is characterized both before and after covering.

Muelenberg, A.↗
NASA NTRS1981

On the global circulation and the hurricane system of the Jovian atmosphere

An argument is made to support the proposal that Jupiter's red spot and the white and brown ovals are hurricanes or cyclones. Against the background of a convectively unstable troposphere, the general condition exists for the formation of hurricanes. The energy Jupiter emits must be transported upwards through the troposphere. If that transport is accelerated by the prevailing upward motions in the solar driven multicellular meridional circulation, eastward jets develop such as observed in the l region. But if that vertical transport is impeded by the prevailing downward motions in the meridional circulation, the atmosphere reacts and tends to maintain the process through the development of hurricanes. Dynamically induced by solar differential heating, an ordered latitudinal structure with alternating stability and instability is impressed on the troposphere to form alternating zonal strata where hurricanes are forbidden and permitted, respectively.

Mayr, H. G.↗