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Cooperative processing for the 1990's using client-server technology is addressed. The main theme is concepts of downsizing from mainframes and minicomputers to workstations on a local area network (LAN). This document is presented in view graph form.
The hardware specification for the Scanning Modulation Collimator (MC) experiment on HEAO-1 was to measure positions of bright (greater than 10(exp -11) ergs/cm(exp 2)s), hard (1 to 15 keV) x-ray sources to 5-10 arcsec, and to measure their size and structure in three energy bands down to 10 arcsec resolution. The scientific purpose of this specification was to enable the identification of these x-ray sources with optical and radio objects in order to elucidate the x-ray emission mechanism and the nature of the candidate astronomical system. The experiment was an outstanding success. Hardware systems functioned perfectly although loss of one (out of eight) proportional counters degraded our sensitivity by about 10 percent. Our aspect solution of 7 arcsec precision, allowed us to achieve statistic-limited location precision for all but the strongest sources. We vigorously pursued a strategy of determining the scientific importance of each identification, and of publishing each scientific result as it came along.
The Long Duration Exposure Facility (LDEF) carried 57 experiments and 10,000 specimens for some 200 LDEF experiment investigators. The external surface of LDEF had a large variety of materials exposed to the space environment which were tested preflight, during flight, and post flight. Thermal blankets, optical materials, thermal control paints, aluminum, and composites are among the materials flown. The investigations have produced an abundance of analysis results. One of the responsibilities of the Boeing Support Contract, Materials and Systems Special Investigation Group, is to collate and compile that information into an organized fashion. The databases developed at Boeing to accomplish this task is described.
We describe in this paper the modifications, improvements, and enhancements to the HITRAN molecular absorption database that have occurred in the two editions of 1991 and 1992. The current database includes line parameters for 31 species and their isotopomers that are significant for terrestrial atmospheric studies. This line-by-line portion of HITRAN presently contains about 709,000 transitions between 0 and 23,000/cm and contains three molecules not present in earlier versions: COF2, SF6, and H2S. The HITRAN compilation has substantially more information on chlorofluorocarbons and other molecular species that exhibit dense spectra which are not amenable to line-by-line representation. The user access of the database has been advanced, and new media forms are now available for use on personal computers.
The relationships between galaxy properties in the sample of Trinchieri et al. (1989) are reexamined with corrections for Malmquist bias. The linear correlations are tested and linear regressions are fit for log-log plots of L(FIR), L(H-alpha), and L(B) as well as ratios of these quantities. The linear correlations for Malmquist bias are corrected using the method of Verter (1988), in which each galaxy observation is weighted by the inverse of its sampling volume. The linear regressions are corrected for Malmquist bias by a new method invented here in which each galaxy observation is weighted by its sampling volume. The results of correlation and regressions among the sample are significantly changed in the anticipated sense that the corrected correlation confidences are lower and the corrected slopes of the linear regressions are lower. The elimination of Malmquist bias eliminates the nonlinear rise in luminosity that has caused some authors to hypothesize additional components of FIR emission.
All earth-looking photographs acquired by Space Shuttle astronauts are identified, located, and catalogued after each mission. The photographs have been entered into a computerized database at the NASA Johnson Space Center. The database in its two modes - computer and catalog - is organized and presented to provide a scope and level of detail designed to be useful in Earth science activities, resource management, environmental studies, and public affairs. The computerized database can be accessed free through standard communication networks 24 hours a day, and the catalogs are distributed throughout the world. Photograph viewing centers are available in the United States, and photographic copies can be obtained through government-supported centers.
Between 1979 and 1992 we took some 120,000 measurements of atmospheric methane at Cape Meares on the Oregon coast. The site is representative of methane concentrations in the northern latitudes (from 30 deg N to 90 deg N). The average concentration during the experiment was 1698 parts per billion by volume (ppbv). Methane concentration increased by 190 ppbv (or 11.9 percent) during the 13-year span of the experiment. The rate of increase was about 20 +/- 4 ppbv/yr in the first 2 yr and 10 +/- 2 ppbv/yr in the last 2 yr of the experiment, suggesting a substantial decline in the trend at northern middle and high latitudes. Prominent seasonal cycles were observed. During the year, the concentration stays more or less constant until May and then starts falling, reaching lowest levels in July and August, then rises rapidly to nearly maximum concentrations in October. Interannual variations with small amplitudes of 2-3 ppbv occur with periods of 1.4 and 6.5 yr.
The National Oceanic and Atmospheric Administration (NOAA) Wave Propagation Laboratory (WPL) presently operates five dual-channel microwave radiometers, one triple-channel microwave radiometer, and one six-channel microwave radiometer. The dual-channel radiometers operate at frequencies of 20.6 or 23.87 GHz and 31.4 or 31.65 GHz. The triple-channel radiometer operates at 20.6, 31.65, and 90.0 GHz. The six-channel radiometer operates at frequencies of 20.6, 31.65, 52.85, 53.85, 55.45, and 58.8 GHz. Recent brightness temperature measurements and attenuation values from some of the above radiometers are presented. These radiometric measurements, taken in different locations throughout the world, have given WPL a diverse set of measurements under a variety of atmospheric conditions. We propose to do a more complete attenuation analysis on these measurements in the future. In addition, a new spinning reflector was installed recently for the dual-channel radiometer at the Platteville, Colorado site. This reflector will extend our measurement capabilities during precipating conditions. Locating the three-channel and portable dual-channel radiometers at or near Greeley, Colorado to support the Advanced Communications Technology Satellite (ACTS) program is discussed.
The day will come when the United States will want to return to the Earth's Moon. When that occurs, NASA may look to the Apollo program for technical and inspirational guidance. The Apollo program, however, was designed to be an end to itself--the landing of a man on the Moon and his return safely within the decade of the 1960's. When that was accomplished, the program folded because it was not self-sustaining. The next time we return to the Moon, we should base our planning on a program that is designed to be a sustained effort for an indefinite period. It is the thrust of this report that the South Pole Station of the National Science Foundation can be used to develop analogs for the construction, funding, and logistical support of a lunar base. Other analogs include transportation and national efforts versus international cooperation. A recommended lunar base using the South Pole Station as inspiration is provided, as well as details concerning economical construction of the base over a 22-year period.
NASA Headquarters is placing a high priority on the transfer of NASA and NASA contractor developed technologies and expertise to the private sector and to other federal, state and local government organizations. The ultimate objective of these efforts is positive economic impact, an improved quality of life, and a more competitive U.S. posture in international markets. The Technology Utilization Office (TUO) currently serves seven states with its technology transfer efforts. Since 1989, the TUO has handled over one-thousand formal requests for NASA related technologies assistance. The technology transfer process requires promoting public awareness of NASA related soliciting requests for assistance, matching technologies to specific needs, assuring appropriate technology transfer, and monitoring and evaluating the process. Each of these activities have one very important aspect in common: the success of each is dissemination of appropriate high quality information. The purpose of the research was to establish the requirements and develop a preliminary design for a database system to increase the effectiveness and efficiency of the TUO's technology transfer function. The research was conducted following the traditional systems development life cycle methodology and was supported through the use of modern structured analysis techniques. The next section will describe the research and findings as conducted under the life cycle approach.
We find large location errors and error radii in the locations of channel 1 Cygnus X-1 events. These errors and their associated uncertainties are a result of low signal-to-noise ratios (a few sigma) in the two brightest detectors for each event. The untriggered events suffer from similarly low signal-to-noise ratios, and their location errors are expected to be at least as large as those found for Cygnus X-1 with a given signal-to-noise ratio. The statistical error radii are consistent with those found for Cygnus X-1 and with the published estimates. We therefore expect approximately 20 - 30 deg location errors for the untriggered events. Hence, many of the untriggered events occurring within a few months of the triggered activity from SGR 1900 plus 14 are indeed consistent with the SGR source location, although Cygnus X-1 is also a good candidate.
NASA's Aviation Safety Reporting System (ASRS) incident reports are reviewed in two related areas: pilots' failures to appropriately manage tasks, and breakdowns in geographic orientation. Examination of 51 relevant reports on task management breakdowns revealed that altitude busts and inappropriate runway usee were the most frequently reported consequences. Task management breakdowns appeared to occur at all levels of expertise, and prominent causal factors were related to breakdowns in crew communications, over-involvement with the flight management system and, for small (general aviation) aircraft, preoccupation with weather. Analysis of the 83 cases of geographic disorientation suggested that these too occurred at all levels of pilot experience. With regard to causal factors, a majority was related to poor cockpit resource management, in which inattention led to a loss of geographic awareness. Other leading causes were related to poor weather and poor decision making. The potential of the ASRS database for contributing to research and design issues is addressed.
The flow behind the shock wave formed around objects which fly at hypervelocity behaves differently from that of a perfect gas. Molecules become vibrationally excited, dissociated, and ionized. The hot gas may emit or absorb radiation. When the atoms produced by dissociation reach the wall surface, chemical reactions, including recombination, may occur. The thermochemical phenomena of vibration, dissociation, ionization, surface chemical reaction, and radiation are referred to commonly as high-temperature real-gas phenomena. The phenomena cause changes in the dynamic behavior of the flow and the surface pressure and heat transfer distribution around the object. The character of a real gas is described by the internal degrees of freedom and state of constituent molecules; nitrogen and oxygen for air. The internal energy states, rotation, vibration and electronic, of the molecules are excited and, in the limit, the molecular bonds are exceeded and the gas dissociated into atomic and, possibly, ionic constituents. The process of energy transfer causing excitation, dissociation and recombination is a rate process controlled by particle collisions. Binary, two-body, collisions are sufficient to cause internal excitation, dissociation and ionization while three-body collisions are required to recombine the particles into molecular constituents. If the rates of energy transfer are fast with respect to the local fluid dynamic time scale the gas is in, or nearly in, equilibrium. If the energy transfer rates are very slow the gas can be described as frozen. In all other instances, wherein any of the energy exchange rates are comparable to the local fluid time scale, the gas will be thermally or chemically reacting and out of equilibrium. Real gas thermochemical nonequilibrium processes are important in the determination of aerodynamic heating; both convective (including wall catalytic effects) and radiative heating. To illustrate this we consider the hypervelocity flow over a bluff body typical of an atmospheric entry vehicle or an aerospace transfer vehicle (ASTV). The qualitative aspects of a hypersonic flow field over a bluff body are discussed in two parts, forebody and afterbody, with attention to which particular physical effects must be included in an analysis. This will indicate what type of numerical modeling will be adequate in each region of the flow. A bluff forebody flow field is dominated by the presence of the strong bow shock wave and the consequent heating, and chemical reaction of the gas. At high altitude hypersonic flight conditions the thermal excitation and chemical reaction of the gas occur slowly enough that a significant portion of the flow field is in a state of thermochemical nonequilibrium. A second important effect is the presence of the thick boundary layer along the forebody surface. In this region there are large thermal and chemical species gradients due to the interaction of the gas with the wall. Also at high altitudes the shock wave and the boundary layer may become so thick that they merge; in this case the entire shock layer is dominated by viscous effects.
The paradigm of client/server computing is changing. The model of a server running a monolithic application and supporting clients at the desktop is giving way to a different model that blurs the line between client and server. We are on the verge of plunging into the next generation of computing technology--distributed object-oriented computing. This is not only a change in requirements but a change in opportunities, and requires a new way of thinking for Information System (IS) developers. The information system demands caused by global competition are requiring even more access to decision making tools. Simply, object-oriented technology has been developed to supersede the current design process of information systems which is not capable of handling next generation multimedia.
Accurate knowledge of certain collision-induced absorption continua of molecular pairs such as H2-H2, H2-He, H2-CH4, CO2-CO2, etc., is a prerequisite for most spectral analyses and modelling attempts of atmospheres of planets and cold stars. We collect and regularly update simple, state of the art computer programs for the calculation of the absorption coefficient of such molecular pairs over a broad range of temperatures and frequencies, for the various rotovibrational bands. The computational results are in agreement with the existing laboratory measurements of such absorption continua, recorded with a spectral resolution of a few wavenumbers, but reliable computational results may be expected even in the far wings, and at temperatures for which laboratory measurements do not exist. Detailed information is given concerning the systems thus studied, the temperature and frequency ranges considered, the rotovibrational bands thus modelled, and how one may obtain copies of the FORTRAN77 computer programs by e-mail.
This portion of the Data Assimilation and Numerical Weather Prediction Benefits presentation will describe: the need for remotely sensed data, the types of observations that have been made and will be available, how satellite data have been and are being assimilated, the impact of the data on weather analysis and prediction in both the U.S and abroad and the potential impact of new observing systems on NWP. Specific observing systems that will be discussed include: satellite temperature and moisture soundings/radiances (TOVS, ATOVS, AIRS/AMSU), satellite surface winds from both passive and active microwave atmospheric motion winds (from MODIS or MISR) precipitation measurements clouds and land surface measurements (e.g. from MODIS) lidar wind profiles.
The Multi-Instrument Integrated Data Acquisition System (MIIDAS), developed by the NASA Langley Research Center, uses commercial off the shelf (COTS) products, integrated with custom software, to provide a broad range of capabilities at a low cost throughout the system s entire life cycle. MIIDAS combines data acquisition capabilities with online and post-test data reduction computations. COTS products lower purchase and maintenance costs by reducing the level of effort required to meet system requirements. Object-oriented methods are used to enhance modularity, encourage reusability, and to promote adaptability, reducing software development costs. Using only COTS products and custom software supported on multiple platforms reduces the cost of porting the system to other platforms. The post-test data reduction capabilities of MIIDAS have been installed at four aerospace testing facilities at NASA Langley Research Center. The systems installed at these facilities provide a common user interface, reducing the training time required for personnel that work across multiple facilities. The techniques employed by MIIDAS enable NASA to build a system with a lower initial purchase price and reduced sustaining maintenance costs. With MIIDAS, NASA has built a highly flexible next generation data acquisition and reduction system for aerospace test facilities that meets customer expectations.
No abstract available