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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 325 records · Page 18
All sourcesNASA NTRSDOE OSTI
NASA NTRS1981

The Geothermal Probabilistic Cost Model with an Application to a Geothermal Reservoir at Heber, California

A financial accounting model that incorporates physical and institutional uncertainties was developed for geothermal projects. Among the uncertainties it can handle are well depth, flow rate, fluid temperature, and permit and construction times. The outputs of the model are cumulative probability distributions of financial measures such as capital cost, levelized cost, and profit. These outputs are well suited for use in an investment decision incorporating risk. The model has the powerful feature that conditional probability distribution can be used to account for correlations among any of the input variables. The model has been applied to a geothermal reservoir at Heber, California, for a 45-MW binary electric plant. Under the assumptions made, the reservoir appears to be economically viable.

Orren, L. H.↗
NASA NTRS1982

Advanced Czochralski silicon growth technology for photovoltaic modules

Several economic analyses had indicated that large-diameter, multiple ingot growth using a single crucible with melt replenishment would be required for Cz growth to be economically viable. Based on the results of these analyses, two liquid and two solid feed melt replenishment approaches were initiated. The sequential solid feed melt replenishment approach, which demonstrated elements of technical feasibility is described in detail in this paper. Growth results of multiple ingots (10-cm-diameter, totaling 100 kg; and 15-cm-diameter, totaling 150 kg weight per crucible) are presented. Solar cells were fabricated and analyzed to evaluate the effects of structure and chemical purities as a result of multiple growth. The results indicate that, with semiconductor-grade silicon, feedstock impurity build-up does not seem to degrade cell performance. For polycrystalline cells, the average efficiencies are 15 to 25% lower than those of single crystalline cells. Concerns regarding single crystal yields, crucible quality and growth speed are indicated, and present status and future research thrusts are also discussed.

Daud, T.↗
NASA NTRS1983

Customer premise service study for 30/20 GHz satellite system

Satellite systems in which the space segment operates in the 30/20 GHz frequency band are defined and compared as to their potential for providing various types of communications services to customer premises and the economic and technical feasibility of doing so. Technical tasks performed include: market postulation, definition of the ground segment, definition of the space segment, definition of the integrated satellite system, service costs for satellite systems, sensitivity analysis, and critical technology. Based on an analysis of market data, a sufficiently large market for services is projected so as to make the system economically viable. A large market, and hence a high capacity satellite system, is found to be necessary to minimize service costs, i.e., economy of scale is found to hold. The wide bandwidth expected to be available in the 30/20 GHz band, along with frequency reuse which further increases the effective system bandwidth, makes possible the high capacity system. Extensive ground networking is required in most systems to both connect users into the system and to interconnect Earth stations to provide spatial diversity. Earth station spatial diversity is found to be a cost effective means of compensating the large fading encountered in the 30/20 GHz operating band.

Milton, R. T.↗
NASA NTRS1983

Designing for a new era of launch vehicle operational efficiency

It is pointed out that early recognition of operational requirements and assessment of their effects provides the best chance of designing an economically viable future space transportation system (FSTS). Operational factors which may influence configuration design include fleet size, operation mode, refurbishment, and the resource requirements. FTST has a simplified operational role compared to the Space Shuttle, which, in addition to transportation, must perform experiments, support payloads, and stay long on orbit. In the future a space station will perform many of these tasks. The FSTS comprises a two-stage fully reusable launch vehicle designed to carry 150,000 lb to a space station, off-load, and return. It would always be launched fully loaded, and its cargo would be processed and redistributed at the space station. Attention is given to ground servicing, flight operations, rendezvous-compatible orbits, launch windows, standard trajectories, entry windows, operational costs, the mission model, and resource requirements.

Talay, T. A.↗
NASA NTRS1983

Progress in supersonic cruise technology

The Supersonic Cruise Research (SCR) program identified significant improvements in the technology areas of aerodynamics, structures, propulsion, noise reduction, takeoff and landing procedures, and advanced configuration concepts. These improvements, when combined in a large supersonic cruise vehicle, offer a far greater technology advance than generally realized. They offer the promise of an advanced commercial family of aircraft which are environmentally acceptable, have flexible range-payload capability, and are economically viable. These same areas of technology have direct application to smaller advanced military aircraft and to supersonic executive aircraft. Several possible applications will be addressed.

Driver, C.↗
NASA NTRS1985

Readying technology for a super SST

A technology readiness evaluation is made of the configurational, propulsion system, avionics, and materials/manufacturing methods which could be integrated to produce an economically viable SST by the year 2000. Aerodynamically, promising results are noted in the cases of arrow-wing planforms and blended wing/body cross sections, as well as in vortex flaps. In structures, metal matrix composites with high specific strength at high temperatures and thermoplastically formed/diffusion-bonded titanium alloy sandwich structures are identified as being of primary importance. Performance improvement prospects are also noted for engine efficiencies and sonic boom overpressures. The various technologies are envisaged as the bases for a two-engine, two-crew cockpit, 250-seat arrow-winged SST.

Petersen, R. H.↗
NASA NTRS1985

Transfer molding of PMR-15 polyimide resin

Transfer molding is an economically viable method of producing small shapes of PMR-15 polyimide. It is shown that with regard to flexural, compressive, and tribological properties transfer-molded PMR-15 polyimide is essentially equivalent to PMR-15 polyimide produced by the more common method of compression molding. Minor variations in anisotropy are predictable effects of molding design and secondary finishing operations.

Reardon, J. P.↗
NASA NTRS1985

Power conditioning subsystems for photovoltaic central-station power plants - Technology and performance

Central-Station (CS) Photovoltaic (PV) systems have the potential of economically displacing significant amounts of centrally generated electricity. However, the technical viability and, to some extent, the economic viability of central-station PV generation technology will depend upon the availability of large power conditioners that are efficient, safe, reliable, and economical. This paper is an overview of the technical and cost requirements that must be met to develop economically viable power conditioning subsystems (PCS) for central-station power plants. The paper also examines various already commercially available PCS hardware that may be suitable for use in today's central PV power stations.

Krauthamer, S.↗
NASA NTRS1986

Power conditioning subsystems for photovoltaic central-station power plants - State-of-the-art and advanced technology

An overview is given of the technical and near-term cost requirements that must be met to develop economically viable power conditioning subsystems (PCS) for large-scale, central photovoltaic power stations. Various commercially available PCS hardware suitable for use in today's central photovoltaic power stations are also surveyed. Federal and industrial activities in the research and development of advanced PCSs that will contribute to the attainment of fully competitive, large-scale photovoltaic power stations are reviewed. The status of the DOE central station PCS program is discussed.

Bulawka, A.↗
NASA NTRS1987

Mass storage systems for data transport in the early space station era 1992-1998

NASA's Space Station Program will provide a vehicle to deploy an unprecedented number of data producing experiments and operational devices. Peak down link data rates are expected to be in the 500 megabit per second range and the daily data volume could reach 2.4 terabytes. Such startling requirements inspired an internal NASA study to determine if economically viable data storage solutions are likely to be available to support the Ground Data Transport segment of the NASA data system. To derive the requirements for data storage subsystems, several alternative data transport architectures were identified with different degrees of decentralization. Data storage operations at each subsystem were categorized based on access time and retrieval functions, and reduced to the following types of subsystems: First in First out (FIFO) storage, fast random access storage, and slow access with staging. The study showed that industry funded magnetic and optical storage technology has a reasonable probability of meeting these requirements. There are, however, system level issues that need to be addressed in the near term.

Carper, Richard↗
NASA NTRS1988

Processes and energy costs for mining lunar Helium-3

Preliminary investigations show that obtaining He-3 from the moon is technically feasible and economically viable. With the exception of beneficiation, the proposed procedures are state of the art. Mass of equipment needed from earth is of some concern, but resupply will eventually be ameliorated by the use of titanium from indigenous ilmenite. A complete energy payback from a D/He-3 fusion reactor utilizing lunar He-3 is approx. 80, providing ample incentive for commercial investment is forthcoming. Byproducts will be of great value to the resupply of a permanent lunar base and enhancement of space exploration.

Sviatoslavsky, I. N.↗
NASA NTRS1990

Romans to Mars

The key role played by technology advancement with respect to the anticipated era of discovery and exploration (in space) is illustrated: how bold new initiatives may or may not be enabled. A truly enabling technology not only renders the proposed missions technically feasible, but also makes them viable economically; that is, low enough in cost (relative to the economy supporting them) that urgent national need is not required for justification, low enough in cost that high risk can be programmatically tolerated. A fictional parallel is drawn to the Roman Empire of the second century A.D., shown to have possessed by that time the necessary knowledge, motivation, means, and technical capability of mounting, through the use of innovative mission planning, an initiative similar to Columbus' voyage. They failed to do so because they lacked the advanced technology necessary to make it an acceptable proposition economically. Speculation, based on the historical perspective, is made on the outcome of contemporary plans for future exploration showing how they will be subjected to the same historical forces, within limits imposed by the state of technology development, that shaped the timing of that previous era of discovery and exploration.

Bents, D. J.↗
NASA NTRS1990

The lessons of Varsovian's reconnaissance

The role played by advanced technology is illustrated with respect to the anticipated era of discovery and exploration (in space): how bold new exploration initiatives may or may not be enabled. Enabling technology makes the mission feasible. To be truly enabling, however, the technology must not only render the proposed mission technically feasible, but also make it viable economically; that is, low enough in cost (relative to the economy supporting it) that urgent national need is not required for justification, low enough that risks can be programmatically tolerated. An allegorical parallel is drawn to the Roman Empire of the second century AD, shown to have possessed by that time the necessary knowledge, motivation, means, and technical capability of mounting, through the use of innovative mission planning, an initiative similar to Columbus' voyage. They failed to do so; not because they lacked the vision, but because their technology was not advanced enough to make it an acceptable proposition economically. Speculation, based on the historical perspective, is made on the outcome of contemporary plans for future exploration showing how they will be subjected to the same historical forces, within limits imposed by the state of technology development, that shaped the timing of that previous era of discovery and exploration.

Bents, D. J.↗
NASA NTRS1988

Operational cost drivers

To be economically viable, the operations cost of launch vehicles must be reduced by an order of magnitude as compared to the Space Transportation System (STS). A summary of propulsion-related operations cost drivers derived from a two-year study of Shuttle ground operations is presented. Examples are given of the inordinate time and cost of launch operations caused by propulsion systems designs that did not adequately consider impacts on prelaunching processing. Typical of these cost drivers are those caused by central hydraulic systems, storable propellants, gimballed engines, multiple propellants, He and N2 systems and purges, hard starts, high maintenance turbopumps, accessibility problems, and most significantly, the use of multiple, nonintegrated RCS, OMS, and main propulsion systems. Recovery and refurbishment of SRBs have resulted in expensive crash and salvage operations. Vehicle system designers are encouraged to be acutely aware of these cost drivers and to incorporate solutions (beginning with the design concepts) to avoid business as usual and costs as usual.

Scholz, Arthur L.↗
NASA NTRS1990

NASA's High Speed Research Program - An introduction and status report

NASA's High Speed Research Program (HSRP) gives attention to the potential environmental effects of a next-generation SST in three areas of concern: atmospheric pollution, airport community noise, and sonic boom. Research has accordingly been undertaken in such fields as the validation of ozone depletion predictions, the feasibility a 90-percent NO(x) emissions reduction to minimize ozone-layer impacts, economically viable compliance with FAR 36 Stage 3 airport community noise levels, and the comparative advantages of efficient subsonic flight over land masses or low-sonic-boom-optimized configurations. Interim HSRP milestones for 1991 and 1992 are noted.

Wesoky, Howard L.↗
NASA NTRS1992

Designing a Methodology for Future Air Travel Scenarios

The growing demand on air travel throughout the world has prompted several proposals for the development of commercial aircraft capable of transporting a large number of passengers at supersonic speeds. Emissions from a projected fleet of such aircraft, referred to as high-speed civil transports (HSCT's), are being studied because of their possible effects on the chemistry and physics of the global atmosphere, in particular, on stratospheric ozone. At the same time, there is growing concern about the effects on ozone from the emissions of current (primarily subsonic) aircraft emissions. Evaluating the potential atmospheric impact of aircraft emissions from HSCT's requires a scientifically sound understanding of where the aircraft fly and under what conditions the aircraft effluents are injected into the atmosphere. A preliminary set of emissions scenarios are presented. These scenarios will be used to understand the sensitivity of environment effects to a range of fleet operations, flight conditions, and aircraft specifications. The baseline specifications for the scenarios are provided: the criteria to be used for developing the scenarios are defined, the required data base for initiating the development of the scenarios is established, and the state of the art for those scenarios that have already been developed is discussed. An important aspect of the assessment will be the evaluation of realistic projections of emissions as a function of both geographical distribution and altitude from an economically viable commercial HSCT fleet. With an assumed introduction date of around the year 2005, it is anticipated that there will be no HSCT aircraft in the global fleet at that time. However, projections show that, by 2015, the HSCT fleet could reach significant size. We assume these projections of HSCT and subsonic fleets for about 2015 can the be used as input to global atmospheric chemistry models to evaluate the impact of the HSCT fleets, relative to an all-subsonic future fleet. The methodology, procedures, and recommendations for the development of future HSCT and the subsonic fleet scenarios used for this evaluation are discussed.

Wuebbles, Donald J.↗
NASA NTRS1992

Design and analysis issues of integrated control systems for high-speed civil transports

A study was conducted to identify, rank, and define development plans for the critical guidance and control design and analysis issues as related to economically viable and environmentally acceptable high-speed civil transport. The issues were identified in a multistep process. First, pertinent literature on supersonic cruise aircraft was reviewed, and experts were consulted to establish the fundamental characteristics and problems inherent to supersonic cruise aircraft. Next, the advanced technologies and strategies being pursued for the high-speed civil transport were considered to determine any additional unique control problems the transport may have. Finally, existing technologies and methods were examined to determine their capabilities for the design and analysis of high-speed civil transport control systems and to identify the shortcomings and issues. Three priority levels - mandatory, highly beneficial, and desirable - were established. Within each of these levels, the issues were further ranked. Technology development plans for each issue were defined. Each plan contains a task breakdown and schedule.

Mccarty, Craig A.↗