High cycle life sealed silver oxide-zinc cell development Final report, 14 Feb. 1969 - 20 Jun. 1970
Developing sealed silver-zinc cell for power supply on interplanetary spacecraft
Farris, C. D.↗
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Results for “cycle life”
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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Life cycle of brief CAT episodes determined by mesoscale analysis.
Using finely detailed data of the 1970 Haven Hop rawisonde network, it is shown that accurate delineation of clear air turbulence in space and short-term forecasting of CAT are possible with rawinsondes aviable at short time intervals and in a dense network. The present synoptic rawinsonde network of widely spaced stations with 12-hr observation intervals is insufficient to provide accurate depiction of meteorological functions accompanying CAT.
Boucher, R. J.↗
Numerical simulation of life cycles of advection warm fog
The formation, development and dissipation of advection warm fog is investigated. The equations employed in the model include the equation of continuity, momentum and energy for the descriptions of density, wind component and potential temperature, respectively, together with two diffusion equations for the modification of water-vapor mixing ratio and liquid-water mixing ratios. A description of the vertical turbulent transfer of heat, moisture and momentum has been taken into consideration. The turbulent exchange coefficients adopted in the model are based on empirical flux-gradient relations.
Hung, R. J.↗
A life-cycle description of underground coal mining
An initial effort to relate the major technological and economic variables which impact conventional underground coal mining systems, in order to help identify promising areas for advanced mining technology is described. The point of departure is a series of investment analyses published by the United States Bureau of Mines, which provide both the analytical framework and guidance on a choice of variables.
Lavin, M. L.↗
Terrestrial central station array life-cycle analysis support study
Plant elements evaluated included designs for module, panel and array structures, as well as balance-of-plant systems. Installation and maintenance procedures and the impact of site environment were also evaluated. In terms of the cost of energy produced, the horizontal array configuration was found to be less expensive than the tandem array at latitudes less than 40 deg. Both of these configurations are less expensive than the rack design. However, the costs of energy for all three configurations are within approximately ?10 percent of each other. For flat plate panels, the seasonally adjusted and tracking array configurations are not economically attractive when compared to the three other designs. Balance-of-plant costs are approximately equal to (goal) module costs. The array structures and foundations are the most expensive items in the balance-of-plant costs.
Source record↗
Cycle life test
Statistical information concerning cell performance characteristics and limitations of secondary spacecraft cells is presented. Weaknesses in cell design as well as battery weaknesses encountered in various satellite programs are reported. Emphasis is placed on improving the reliability of space batteries.
Harkness, J. D.↗
Analytical modeling of battery cycle life
An analytical model related to the physical and chemical processes involved in battery wear and failure is discussed. The model is described using the data from the Crane tests.
Gross, S.↗
Computerized systems analysis and optimization of aircraft engine performance, weight, and life cycle costs
The computational techniques are described which are utilized at Lewis Research Center to determine the optimum propulsion systems for future aircraft applications and to identify system tradeoffs and technology requirements. Cycle performance, and engine weight can be calculated along with costs and installation effects as opposed to fuel consumption alone. Almost any conceivable turbine engine cycle can be studied. These computer codes are: NNEP, WATE, LIFCYC, INSTAL, and POD DRG. Examples are given to illustrate how these computer techniques can be applied to analyze and optimize propulsion system fuel consumption, weight and cost for representative types of aircraft and missions.
Fishbach, L. H.↗
Computerized systems analysis and optimization of aircraft engine performance, weight, and life cycle costs
The paper describes the computational techniques employed in determining the optimal propulsion systems for future aircraft applications and to identify system tradeoffs and technology requirements. The computer programs used to perform calculations for all the factors that enter into the selection process of determining the optimum combinations of airplanes and engines are examined. Attention is given to the description of the computer codes including NNEP, WATE, LIFCYC, INSTAL, and POD DRG. A process is illustrated by which turbine engines can be evaluated as to fuel consumption, engine weight, cost and installation effects. Examples are shown as to the benefits of variable geometry and of the tradeoff between fuel burned and engine weights. Future plans for further improvements in the analytical modeling of engine systems are also described.
Fishbach, L. H.↗
Software costing and life cycle control
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Putnam, L. H.↗
Some theoretical perspectives on developing a software life cycle data base
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Curtis, B.↗
Life cycle cost analysis of shuttle-derived launch vehicles. Volume 2: Executive summary
A digest of study approach and findings used at an oral briefing is presented.
Source record↗
Use of fiber-like materials to augment cycle life of thick, thermoprotective-seal coatings
(Previously announced in STAR as N82-32633)
Hendricks, R. C.↗
Results of chopper-controlled discharge life cycling studies on lead-acid batteries
(previously announced in STAR as N82-30700)
Ewashinka, J. G.↗
On-orbit spacecraft/stage servicing during STS life cycle
A comprehensive and repesentative set of shuttle payloads was identified for shuttle and space station servicing missions. The classes of servicing functions were determined and the general servicing support required for the set of referenced spacecraft was allocated. A candidtate strawman space station was depicted from a synthesis of space station concepts derived from NASA space station architecture studies done by eight contractors. The shuttle servicing hardware and kits were identified and their applicability in transitioning servicing capability to the space station was evaluated.
Source record↗
Life cycle test results of a bipolar nickel hydrogen battery
A history of low Earth orbit laboratory test data on a 6.5 Ah bipolar nickel hydrogen battery designed and built at the NASA Lewis Research Center is presented. During the past several years the Storage and Thermal Branch has been deeply involved in the design, development, and optimization of nickel hydrogen devices. The bipolar concept is a means of achieving the goal of producing an acceptable battery of higher energy density, able to withstand the demands of low Earth orbit regimes.
Cataldo, R. L.↗
Life cycle test results of a bipolar nickel hydrogen battery
A history is given of low Earth orbit (LEO) laboratory test data on a 6.5 ampere-hour bipolar nickel hydrogen battery designed and built at the NASA Lewis Research Center. The bipolar concept is a means of achieving the goal of producing an acceptable battery, of higher energy density, able to withstand the demands of low-Earth-orbit regimes. Over 4100 LEO cycles were established on a ten cell battery. It seems that any perturbation on normal cycling effects the cells performance. Explanations and theories of the battery's behavior are varied and widespread among those closely associated with it. Deep discharging does provide a reconditioning effect and further experimentation is planned in this area. The battery watt-hour efficiency is about 75 percent and the time averaged, discharge voltage is about 1.26 volts for all cells at both the C/4 and LEO rate. Since a significant portion of the electrode capacity has degraded, the LEO cycle discharges are approaching depths of 90 to 100 percent of the high rate capacity. Therefore, the low end-of-discharge voltages occur precipitously after the knee of the discharge curve and is more an indication of electrode capacity and is a lesser indicator of overall cell performance.
Cataldo, R. L.↗
The independence of software metrics taken at different life-cycle stages
Over the past few years a large number of software metrics have been proposed and, in varying degrees, a number of these metrics have been subjected to empirical validation which demonstrated the utility of the metrics in the software development process. Attempts to classify these metrics and to determine if the metrics in these different classes appear to be measuring distinct attributes of the software product are studied. Statistical analysis is used to determine the degree of relationship among the metrics.
Kafura, D.↗