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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 1,567 records · Page 87
All sourcesNASA NTRSDOE OSTI
NASA NTRS1980

Systems analysis - Key to NASA's data system planning

Critical steps in the systems analysis process for NASA's data system planning are: (1) compilation of future user/mission requirements, (2) development of alternative overall data system concepts which satisfy requirements, (3) assessment of future development and availability of data system technology, and (4) cost/performance tradeoff studies of the alternative concepts for systems optimization. Tasks within the NEEDS (NASA End-to-End Data System) Program, which correspond to the critical steps in this systems analysis process are examined.

Nelson, R. W.↗
NASA NTRS1980

Space fabrication - The key to future large space systems

Construction techniques for large space structures are discussed. It is pointed out that in contrast to assembly in orbit and the deployment technique space fabrication offers favorable densities (transporting structural materials on reels) and can be adapted to automated construction. A space fabrication machine containing reels of flat sheet material and sets of rollers or dies is described, as is a machine for fabricating composite material (which must be heated for forming and then cooled to achieve structural strength). The use of fabrication machines to build such structures as space platforms, microwave radiometers, and satellite power systems is discussed. The versatility of the machine when operated in conjunction with the Space Shuttle and a set of jigs is illustrated by showing how large square solar panels and large hexagonal structures could be constructed. The need for a flight demonstration of the fabrication machine is stressed.

Savage, M.↗
NASA NTRS1981

Space operation center - The key to space industrialization

The concept of a Shuttle-serviced Space Operations Center (SOC) and SOC program development are reviewed. The subjects discussed include: projected operational support capabilities, SOC elements and subsystems, and supporting research and technology.

Nassiff, S. H.↗
NASA NTRS1981

Key space telescope design considerations

The Space Telescope (ST), a 2.4 meter aperture astronomical telescope, will be launched into low earth orbit by the Space Shuttle in the mid-1980's. This high resolution telescope will be capable of operating from Lyman-alpha (121.6 nm) through the near infrared; support five different scientific instruments at its focal plane (two cameras, two spectrographs, and one photometer); and by periodic on-orbit servicing and ground refurbishment be able to operate with technologically current scientific instruments for at least 15 years. This paper identifies the critical Space Telescope design requirements and describes design techniques which were selected to satisfy these requirements.

Olivier, J. R.↗
NASA NTRS1981

Key Issues in the Analysis of Remote Sensing Data: A report on the workshop

The procedures of a workshop assessing the state of the art of machine analysis of remotely sensed data are summarized. Areas discussed were: data bases, image registration, image preprocessing operations, map oriented considerations, advanced digital systems, artificial intelligence methods, image classification, and improved classifier training. Recommendations of areas for further research are presented.

Swain, P. H.↗
NASA NTRS1982

Key scientific questions and the role of satellites

Some of the research opportunities that are available from geostationary satellite data, especially from MONEX during the Global Weather Experiment are described. In addition, the International Cloud Climatology Program is described and the use of satellite imagery in studying mesoscale convection complexes is discussed. Finally, information derived from satellite data on ocean winds is examined.

Bierly, E. W.↗
NASA NTRS1984

IGES, a key interface specification for CAD/CAM systems integration

The Initial Graphics Exchange Specification (IGES) program has focused the efforts of 52 companies on the development and documentation of a means of graphics data base exchange among present day CAD/CAM systems. The project's brief history has seen the evolution of the Specification into preliminary industrial usage marked by public demonstrations of vendor capability, mandatory requests in procurement actions, and a formalization into an American National Standard in September 1981. Recent events have demonstrated intersystem data exchange among seven vendor systems with a total of 30 vendors committing to offer IGES capability. A full range of documentation supports the IGES project and the recently approved IGES Version 2.0 of the Specification.

Smith, B. M.↗
NASA NTRS1984

Determination of the key parameters affecting historic communications satellite trends

Data representing 13 series of commercial communications satellites procured between 1968 and 1982 were analyzed to determine the factors that have contributed to the general reduction over time of the per circuit cost of communications satellites. The model by which the data were analyzed was derived from a general telecommunications application and modified to be more directly applicable for communications satellites. In this model satellite mass, bandwidth-years, and technological change were the variable parameters. A linear, least squares, multiple regression routine was used to obtain the measure of significance of the model. Correlation was measured by coefficient of determination (R super 2) and t-statistic. The results showed that no correlation could be established with satellite mass. Bandwidth-year however, did show a significant correlation. Technological change in the bandwidth-year case was a significant factor in the model. This analysis and the conclusions derived are based on mature technologies, i.e., satellite designs that are evolutions of earlier designs rather than the first of a new generation. The findings, therefore, are appropriate to future satellites only if they are a continuation of design evolution.

Namkoong, D.↗
NASA NTRS1984

Global carbon - nitrogen - phosphorus cycle interactions: A key to solving the atmospheric CO2 balance problem?

If all biotic sinks of atmospheric CO2 reported were added a value of about 0.4 Gt C/yr would be found. For each category, a very high (non-conservative) estimate was used. This still does not provide a sufficient basis for achieving a balance between the sources and sinks of atmospheric CO2. The bulk of the discrepancy lies in a combination of errors in the major terms, the greatest being in a combination of errors in the major terms, the greatest being in the net biotic release and ocean uptake segments, but smaller errors or biases may exist in calculations of the rate of atmospheric CO2 increase and total fossil fuel use as well. The reason why biotic sinks are not capable of balancing the CO2 increase via nutrient-matching in the short-term is apparent from a comparison of the stoichiometry of the sources and sinks. The burning of fossil fuels and forest biomass releases much more CO2-carbon than is sequestered as organic carbon.

Peterson, B. J.↗
NASA NTRS1983

Computer science: Key to a space program renaissance. The 1981 NASA/ASEE summer study on the use of computer science and technology in NASA. Volume 2: Appendices

Adoption of an aggressive computer science research and technology program within NASA will: (1) enable new mission capabilities such as autonomous spacecraft, reliability and self-repair, and low-bandwidth intelligent Earth sensing; (2) lower manpower requirements, especially in the areas of Space Shuttle operations, by making fuller use of control center automation, technical support, and internal utilization of state-of-the-art computer techniques; (3) reduce project costs via improved software verification, software engineering, enhanced scientist/engineer productivity, and increased managerial effectiveness; and (4) significantly improve internal operations within NASA with electronic mail, managerial computer aids, an automated bureaucracy and uniform program operating plans.

Freitas, R. A., Jr.↗
NASA NTRS1985

On the detectability of key-MeV solar protons through their nonthermal Lyman-alpha emission

The intensity and timescale of nonthermal Doppler-shifted hydrogen L alpha photon emission as diagnostics of 10 keV to 10 MeV protons bombarding the solar chromosphere during flares are investigated. The steady-state excitation and ionization balance of the proton beam are determined, taking into account all important atomic interactions with the ambient chromosphere. For a proton energy flux comparable to the electron energy flux commonly inferred for large flares, L alpha wing intensities orders of magnitude larger than observed nonflaring values were found. Investigation of timescales for ionization and charge exchange leads researchers to conclude that over a wide range of values of mean proton energy and beam parameters, Doppler-shifted nonthermal L alpha emission is a useful observational diagnostic of the presence of 10 keV to 10 MeV superthermal proton beams in the solar flare chromosphere.

Canfield, R. C.↗
NASA NTRS1984

NGC 7213 - A key to the nature of liners?

New optical spectra of the nearby S0 galaxy NGC 7213 are analyzed. The observations are described and a brief overview of the spectrum is given. The subtraction of the stellar component is presented, and the measurement of various emission lines is discussed in detail. Important physical parameters are derived, including those pertaining to atomic data, line widths, physical conditions, geometry and kinematics, the Balmer decrement, and ultraviolet emission lines. The Seyfert characteristics of NGC 7213 are reviewed, and the galaxy's shock features are reconciled with photoionization models. The presented arguments may apply to classical liners as well. Theoretical models that can help explain the relationships discovered among the emission lines are examined.

Filippenko, A. V.↗
NASA NTRS1985

The key to successful management of STS operations: An integrated production planning system

Space Transportation System operations managers are being confronted with a unique set of challenges as a result of increasing flight rates, the demand for flight manifest/production schedule flexibility and an emphasis on continued cost reduction. These challenges have created the need for an integrated production planning system that provides managers with the capability to plan, schedule, status and account for an orderly flow of products and services across a large, multi-discipline organization. With increased visibility into the end-to-end production flow for individual and parallel missions in process, managers can assess the integrated impact of changes, identify and measure the interrelationships of resource, schedule, and technical performance requirements and prioritize productivity enhancements.

Johnson, W. A.↗
NASA NTRS1985

Some key considerations in evolving a computer system and software engineering support environment for the space station program

The space station data management system involves networks of computing resources that must work cooperatively and reliably over an indefinite life span. This program requires a long schedule of modular growth and an even longer period of maintenance and operation. The development and operation of space station computing resources will involve a spectrum of systems and software life cycle activities distributed across a variety of hosts, an integration, verification, and validation host with test bed, and distributed targets. The requirement for the early establishment and use of an apporopriate Computer Systems and Software Engineering Support Environment is identified. This environment will support the Research and Development Productivity challenges presented by the space station computing system.

Mckay, C. W.↗
NASA NTRS1985

Automation and robotics - Key to productivity

The automated and robotic systems requirements of the NASA Space Station are prompted by maintenance, repair, servicing and assembly requirements. Trend analyses, fault diagnoses, and subsystem status assessments for the Station's electrical power, guidance, navigation, control, data management and environmental control subsystems will be undertaken by cybernetic expert systems; this will reduce or eliminate on-board or ground facility activities that would otherwise be essential, enhancing system productivity. Additional capabilities may also be obtained through the incorporation of even a limited amount of artificial intelligence in the controllers of the various Space Station systems.

Cohen, A.↗
NASA NTRS1985

Communications and tracking - The keys to Space Station utilization

An overview of the Space Station Communications and Tracking System is presented, along with a description of its component parts and the numerous interacting control links. Emphasis is given to explaining the television and data control routing within the confines of the system. The growth expectations for the Space Station are discussed in light of the communications and tracking requirements.

Sawyer, R. S.↗
NASA NTRS1986

Grain temperature fluctuations - A key to infrared spectra

Interstellar grains of radius less than 003 microns are known to have a fluctuating temperature because their internal energy is comparable to the energy of UV and visible photons. The exact resultant grain temperature distribution is given by studying the multiphoton absorption processes. This distribution satisfies an homogeneous integral equation which can be solved by an iteration technique. These small grains generally emit at shorter wavelengths than big cold grians and therefore could help in the interpretation of the infrared spectra (1-1000 microns) of various astrophysical objects.

Desert, F. X.↗