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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 271 records · Page 15

Application of the Man-computer Interactive Data Access System (McIDAS) to aerospace meteorology

The Man-computer Interactive Data Access System (McIDAS) considered in this paper has been in use at Marshall Space Flight Center (MSFC) since 1981. The MSFC McIDAS system is primarily employed as a research tool, taking into account rainfall estimates as deduced from Scanning Multichannel Microwave Radiometer (SMMR) data, remote sensing sensor development (MAMS), Doppler-lidar derived winds, cloud tracked winds, and analysis of lightning ground strike data. With respect to the SMMR data analysis, passive microwave satellite data are displayed on McIDAS as images. Two major research efforts are concerned with the determination of mesoscale winds. These efforts are based on a utilization of a Doppler-lidar system, and GOES multispectral imagery. It is pointed out that future plans include increased usage of the McIDAS system.

Meyer, P. J.↗

The future of earth remote sensing in the US through the Space Station era

This paper reviews the objectives of the Terrestrial Geology Program within NASA. The Geology Program is one of four within the Land Processes Branch of the Office of Space Science and Applications, and complements the Terrestrial Ecosystems, Hydrology and Remote Sensing Science Programs. Examples of science currently being supported by the Geology Program, and new sensor developments are discussed as they lead towards the Space Station Era in the mid-1990's.

Mouginis, P. J.↗

Venus Radar Mapper (VRM) - Multimode radar system design

The paper describes the radar design of the Venus Radar Mapper (VRM), which is intended to acquire global radar imaging and altimetry data of the Venus surface. The radar design requirements are satisfied through the use of an existing Voyager antenna for the SAR function and newly developed sensor and altimeter antenna subsystems. The sensor utilizes a block adaptive quantizer to maximize science data return with minimum transmission of radar data back to earth.

Johnson, William T. K.↗

Boundary layer measurements using hot-film sensors

Measurements in the aerodynamic boundary layer using heat transfer, hot-film sensors are receiving a significant amount of effort at the Langley Research Center. A description of the basic sensor, the signal conditioning employed, and several manifestations of the sensor are given. Results of a flow reversal sensor development are presented, and future work areas are outlined.

Holmes, Harlan K.↗

Sensors for ceramic components in advanced propulsion systems: Summary of literature survey and concept analysis, task 3 report

The results of a literature survey and concept analysis related to sensing techniques for measuring of surface temperature, strain, and heat flux for (non-specific) ceramic materials exposed to elevated temperatures (to 2200 K) are summarized. Concepts capable of functioning in a gas turbine hot section environment are favored but others are reviewed also. Recommendation are made for sensor development in each of the three areas.

Bennethum, W. H.↗

Problems and research issues associated with the hybrid control of force and displacement

The hybrid control of force and position is basic to the science of robotics but is only poorly understood. Before much progress can be made in robotics, this problem needs to be solved in a robust manner. However, the use of hybrid control implies the existence of a model of the environment, not an exact model (as the function of hybrid control is to accommodate these errors), but a model appropriate for planning and reasoning. The monitored forces in position control are interpreted in terms of a model of the task as are the monitored displacements in force control. The reaction forces of the task of writing are far different from those of hammering. The programming of actions in such a modeled world becomes more complicated and systems of task level programming need to be developed. Sensor based robotics, of which force sensing is the most basic, implies an entirely new level of technology. Indeed, robot force sensors, no matter how compliant they may be, must be protected from accidental collisions. This implies other sensors to monitor task execution and again the use of a world model. This new level of technology is the task level, in which task actions are specified, not the actions of individual sensors and manipulators.

Paul, R. P.↗

Remote sensing of canopy chemistry and nitrogen cycling in temperate forest ecosystems

The use of images acquired by the Airborne Imaging Spectrometer, an experimental high-spectral resolution imaging sensor developed by NASA, to estimate the lignin concentration of whole forest canopies in Wisconsin is reported. The observed strong relationship between canopy lignin concentration and nitrogen availability in seven undisturbed forest ecosystems on Blackhawk Island, Wisconsin, suggests that canopy lignin may serve as an index for site nitrogen status. This predictive relationship presents the opportunity to estimate nitrogen-cycling rates across forested landscapes through remote sensing.

Wessman, Carol A.↗

Boundary layer receptivity to freestream turbulence

Freestream turbulence of weak but adjustable intensity incident upon a flat plate test model induced Tollmien-Schichting (TS) waves and wave packets. These were studied using a newly-developed sensor by which the packets could be followed from a station nearly as far forward as the minimum critical Reynolds number to the onset of transition. Conclusions reached from these studies were: (1) weak freestream turbulence induced TS wave packets in a Blasius boundary-layer, (2) packets gained strength during propagation through expansion of lateral and longitudinal scales, and through an increase in peak amplitude, (3) the average wave strength at stations of observation was not related to the freestream velocity fluctuation in a linear manner, and (4) packets typically evolved into turbulent spots.

Kendall, James M.↗

Overview of the instrumentation program

This program is aimed at developing sensors and measurement systems capable of obtaining the data necessary for the verification of computational models of the structural behavior, the fatigue life, and the environmental conditions pertinent to advanced reusable space propulsion systems. One of the characteristics of measurement systems needed to verify codes is that the sensors must be nonintrusive or at least minimally intrusive so as not to significantly perturb the conditions being measured. This leads to a heavy emphasis on laser optical techniques and on thin-film sensors. Another characteristic of such instruments is that they must be highly accurate and produce very high spatial and temporal resolution of the parameter being measured. The measurement systems needed generally fall into a number of broad categories. First there are the measurements needed on the surfaces of components such as turbine blades and vanes. Some of the desired parameters are temperature, strain, and heat flux. Another broad category encompasses those measurements needed in the flow environment around these components. Here, the desired results are high resolution maps of such parameters as flow velocity, temperature, density, pressure, and species concentration. The remaining category deals with measurements necessary for monitoring the health of the engine. This category has loomed ever more important since the Challenger disaster. An optical method for determining the characteristics of the plume is presented. Holographic measurement of structural damage is also presented.

Nieberding, William C.↗

Recent advances in airborne terrestrial remote sensing with the NASA airborne visible/infrared imaging spectrometer (AVIRIS), airborne synthetic aperture radar (SAR), and thermal infrared multispectral scanner (TIMS)

Significant progress in terrestrial remote sensing from the air has been made with three NASA-developed sensors that collectively cover the solar-reflected, thermal infrared, and microwave regions of the electromagnetic spectrum. These sensors are the airborne visible/infrared imaging spectrometer (AVIRIS), the thermal infrared mapping spectrometer (TIMS) and the airborne synthetic aperture radar (SAR), respectively. AVIRIS and SAR underwent extensive in-flight engineering testing in 1987 and 1988 and are scheduled to become operational in 1989. TIMS has been in operation for several years. These sensors are described.

Vane, Gregg↗

Measurement of Attachment-Line Location in a Wind-Tunnel and in Supersonic Flight

As a part of the supersonic laminar flow control research program, experiments are being conducted to measure the attachment-line flow characteristics and its location on a highly swept aircraft wing. Initially, subsonic wind tunnel tests were performed on two-dimensional models to develop sensors and techniques for the flight application. The wind tunnel test results suggest that, under certain conditions at the leading edge there are low frequency streamwise velocity fluctuations present in the laminar boundary layer which undergo a phase change at the stagnation point Therefore, if present in flight, this distinct change in phase, i.e., time shift of signals from either side of the stagnation point, can be used to determine the stagnation-line or attachment-line location. The phase-reversal phenomenon was examined to determine the attachment-line location on a highly swept wing. Test results indicate that the phase-reversal phenomenon may not be applicable in flight. Additional data analyses is continuing to account for phase differences introduced by the recording system. A final determination on the existence of phase-reversal in flight will require the results of further analysis and possibly additional flight testing. Some representative attachment-line data are presented and discussed as well as the results from the wind tunnel investigation.

Flight Testing↗

The Clementine Mission science return at the Moon and Geographos

The Clementine Mission is being built and flown by the Naval Research Laboratory under the sponsorship of the Strategic Defense Initiative Organization of the United States Department of Defense in joint-cooperation with NASA, and will explore the Moon and the near-Earth asteroid (NEA) 1620 Geographos with lightweight sensors developed by the Lawrence Livermore National Laboratory. A NASA Science Team for this mission will be selected by way of a NRA in April 1993. The instrument suite includes imaging cameras that cover a spectral range from the near-ultraviolet to the mid-infrared, a laser ranger, and, potentially, a charged particle telescope. To be launched in early 1994, Clementine will be in lunar orbit from February through May 1994, at which time it will depart the Moon for a flyby of 1620 Geographos in August 1994. This mission represents an outstanding opportunity for scientists interested in the Moon and asteroids. It is anticipated that the data returned from this mission will permit: an assessment of global lunar crustal heterogeneity and a resolution of less than 1 km; an assessment of the lithologic heterogeneity of Geographos at a scale of 100 m or better; and an assessment of surface processes on Geographos on the order of 10 m. The basic mission of Clementine and some of the key scientific questions that will be addressed are described. Additional material on the Clementine mission, its data handling and processing, and its instrument suite is presented elsewhere.

Vorderbruegge, R. W.↗

PULSAUR 2

PULSAUR II is a sounding rocket experiment to investigate the pulsating aurora and related phenomena. The payload consists of a complementary set of instruments designed specifically to look at the pulsating aurora. The project will be managed by the Norwegian Space Center, with integration in Norway. The rocket is due for launch in January 1994 from the Andoya rocket range. Southwest Research Institute provided an electron sensor for this campaign. It is a 'top hat' electron spectrometer, referred to as AREA (Angle Resolving Energy Analyzer), and is based on the electron sensor developed for the CENTAUR mission.

Sharber, Jim↗

Windshear certification data base for forward-look detection systems

Described is an introduction to a comprehensive database that is to be used for certification testing of airborne forward-look windshear detection systems. The database was developed by NASA Langley Research Center, at the request of the Federal Aviation Administration (FAA), to support the industry initiative to certify and produce forward-looking windshear detection equipment. The database contains high-resolution three-dimensional fields for meteorological variables that may be sensed by forward-looking systems. The database is made up of seven case studies that are generated by the Terminal Area Simulation System, a state-of-the-art numerical system for the realistic modeling of windshear phenomena. The selected cases contained in the certification documentation represent a wide spectrum of windshear events. The database will be used with vendor-developed sensor simulation software and vendor-collected ground-clutter data to demonstrate detection performance in a variety of meteorological conditions using NASA/FAA pre-defined path scenarios for each of the certification cases. A brief outline of the contents and sample plots from the database documentation are included. These plots show fields of hazard factor, or F-factor (Bowles 1990), radar reflectivity, and velocity vectors on a horizontal plane overlayed with the applicable certification paths. For the plot of the F-factor field the region of 0.105 and above signify an area of hazardous, performance decreasing windshear, while negative values indicate regions of performance increasing windshear. The values of F-factor are based on 1-Km averaged segments along horizontal flight paths, assuming an air speed of 150 knots (approx. 75 m/s). The database has been released to vendors participating in the certification process. The database and associated document have been transferred to the FAA for archival storage and distribution.

Switzer, George F.↗

Fabrication of Fabry-Perot Interferometer Sensors and Characterization of their Performances for Aircraft Inspection

This work provides the information for fabricating Fabry-Perot Interferometer sensors and their performances. The Fabry-Perot Interferometer sensors developed here will be used for the detection of flaws in aircraft structures. The sequel also contains discussion of the experimental setups for the Ultrasonic technique and the Fabry-Perot Interferometer.

Pendergrass, LeRuth Q.↗

Image Registration Workshop Proceedings

Automatic image registration has often been considered as a preliminary step for higher-level processing, such as object recognition or data fusion. But with the unprecedented amounts of data which are being and will continue to be generated by newly developed sensors, the very topic of automatic image registration has become and important research topic. This workshop presents a collection of very high quality work which has been grouped in four main areas: (1) theoretical aspects of image registration; (2) applications to satellite imagery; (3) applications to medical imagery; and (4) image registration for computer vision research.

LeMoigne, Jacqueline↗

Research and Educational Opportunities with NASA GSFC

The research carried out in the Earth sciences at NASA's Goddard Space Flight Center will be the focus of the presentation. These research interests span the full breath of disciplines in Earth System Science. Branches and research groups focus on areas as diverse as planetary geomagnetics and atmospheric chemistry. There are 4 major laboratories in the directorate and 2 organizations that focus on scientific information technology. These laboratories focus on atmospheric sciences (atmospheric chemistry, climate and radiation, regional processes, atmospheric modeling), hydrological sciences (snow, ice, oceans, and seasonal-to-interannual prediction), terrestrial physics (geology, terrestrial biology, land-atmosphere interactions, geophysics), climate modeling (global warming, greenhouse gases, climate change). Two of the labs also have branches that focus on sensor development especially using lidar and microwave technologies. In the information technologies, areas of scientific and technical research, and expertise include massively parallel computers, technologies for high speed electronic networks, scientific visualization, information systems, archive and distribution systems, and information processing. Examples will be presented from each of these research disciplines.

Meeson, Blanche W.↗