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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 199 records · Page 11

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NASA NTRS1977

The preliminary design of a lift-cruise fan airplane flight control system

This paper presents the preliminary design of a stability augmentation system for a NASA V/STOL research and technology airplane. This stability augmentation system is postulated as the simplest system that meets handling-quality levels for research and technology missions flown by NASA test pilots. The airplane studied in this report is a modified T-39 fitted with tilting lift/cruise fan nacelles and a nose fan. The propulsion system features a shaft that interconnects three variable-pitch fans and three powerplants. The mathematical modeling is based on pre-wind tunnel test estimated data. The selected stability augmentation system uses variable gains scheduled with airspeed. Failure analysis of the system illustrates the benign effect of engine failure. Airplane rate sensor failure must be solved with redundancy.

Gotlieb, P.↗

NASA NTRS1999

Experiments in Aligning Threaded Parts Using a Robot Hand

Techniques for determining and correcting threaded part alignment using force and angular position data are developed to augment currently limited techniques for align- ing threaded parts. These new techniques are based on backspinning a nut with respect to a bolt and measuring the force change that occurs when the bolt "falls" into the nut. Kinematic models that describe the relationship between threaded parts during backspinning are introduced and are used to show how angular alignment may be determined. The models indicate how to distinguish between the aligned and misaligned cases of a bolt and a nut connection by using axial force data only. In addition, by tracking the in-plane relative attitude of the bolt during spinning, data can be obtained on the direction of the angular misalignment which, in turn, is used to correct the misalignment. Results from experiments using a bolt held in a specialized fixture and a three fingers Stanford/JPL hand are presented.

Diftler, M. A.↗

NASA NTRS2011

Supersonic/Hypersonic Correlations for In-Cavity Transition and Heating Augmentation

Laminar-entry cavity heating data with a non-laminar boundary layer exit flow have been retrieved from the database developed at Mach 6 and 10 in air on large flat plate models for the Space Shuttle Return-To-Flight Program. Building on previously published fully laminar and fully turbulent analysis methods, new descriptive correlations of the in-cavity floor-averaged heating and endwall maximum heating have been developed for transitional-to-turbulent exit flow. These new local-cavity correlations provide the expected flow and geometry conditions for transition onset; they provide the incremental heating augmentation induced by transitional flow; and, they provide the transitional-to-turbulent exit cavity length. Furthermore, they provide an upper application limit for the previously developed fully-laminar heating correlations. An example is provided that demonstrates simplicity of application. Heating augmentation factors of 12 and 3 above the fully laminar values are shown to exist on the cavity floor and endwall, respectively, if the flow exits in fully tripped-to-turbulent boundary layer state. Cavity floor heating data in geometries installed on the windward surface of 0.075-scale Shuttle wind tunnel models have also been retrieved from the boundary layer transition database developed for the Return-To-Flight Program. These data were independently acquired at Mach 6 and Mach 10 in air, and at Mach 6 in CF4. The correlation parameters for the floor-averaged heating have been developed and they offer an exceptionally positive comparison to previously developed laminar-cavity heating correlations. Non-laminar increments have been extracted from the Shuttle data and they fall on the newly developed transitional in-cavity correlations, and they are bounded by the 95% correlation prediction limits. Because the ratio of specific heats changes along the re-entry trajectory, turning angle into a cavity and boundary layer flow properties may be affected, raising concerns regarding the application validity of the heating augmentation predictions.

Everhart, Joel L.↗

NASA NTRS1994

Feasibility of an integrated X-ray instrument for Mars exobiology and geology

By employing an integrated X-ray instrument on a future Mars mission, data obtained will greatly augment those returned by Viking; details relevant to the possibility of the origin and evolution of life on Mars will be acquired. An integrated combined X Ray Fluorescence/X Ray Detection (XRF/XRD) instrument has been breadboarded and demonstrated to accommodate important exobiology and geology experiment objectives outlined for Mars Environmental Survey (MESUR) and future Mars missions. Among others, primary objectives for the exploration of Mars include: the intense study of local areas on Mars to 'establish the chemical, mineralogical, and petrological character of different components of the surface material; to determine the distribution, abundance and sources and sinks of volatile materials, including an assessment of the biologic potential, now and during past epochs; and to establish the global chemical and physical characteristics of the Martian surface'. The XRF/XRD breadboard instrument identifies and quantifies soil surface elemental, mineralogical, and petrological characteristics and acquires data necessary to address questions on volatile abundance and distribution. Additionally, the breadboard is able to characterize the biogenic element constituents of soil samples providing information on the biologic potential of the Mars environment.

Fonda, M. L.↗

NASA NTRS1993

An Integrated XRF/XRD Instrument for Mars Exobiology and Geology Experiments

By employing an integrated x-ray instrument on a future Mars mission, data obtained will greatly augment those returned by Viking; details characterizing the past and present environment on Mars and those relevant to the possibility of the origin and evolution of life will be acquired. A combined x-ray fluorescence/x-ray diffraction (XRF/XRD) instrument was breadboarded and demonstrated to accommodate important exobiology and geology experiment objectives outlined for MESUR and future Mars missions. Among others, primary objectives for the exploration of Mars include the intense study of local areas on Mars to establish the chemical, mineralogical, and petrological character of different components of the surface material; to determine the distribution, abundance, and sources and sinks of volatile materials, including an assessment of the biologic potential, now and during past epoches; and to establish the global chemical and physical characteristics of the Martian surface. The XRF/XRD breadboard instrument identifies and quantifies soil surface elemental, mineralogical, and petrological characteristics and acquires data necessary to address questions on volatile abundance and distribution. Additionally, the breadboard is able to characterize the biogenic element constituents of soil samples providing information on the biologic potential of the Mars environment. Preliminary breadboard experiments confirmed the fundamental instrument design approach and measurement performance.

Koppel, L. N.↗

NASA NTRS1975

Prediction of sonic boom from experimental near-field overpressure data. Volume 2: Data base construction

A computerized method for storing, updating and augmenting experimentally determined overpressure signatures has been developed. A data base of pressure signatures for a shuttle type vehicle has been stored. The data base has been used for the prediction of sonic boom with the program described in Volume I.

Glatt, C. R.↗

NASA NTRS1990

Comparisons between Geosat and Seasat tracking over non-ocean surfaces

The differences in both the quantity and quality of the nonocean measurements of the Geosat and Seasat altimeters due to the tracker modifications and satellite and antenna design changes are presented. The Geosat tracker exhibits more agility over the rougher surfaces and therefore is able to maintain lock better than Seasat. Large off-nadir attitude excursions created differences in Geosat tracking between cycles. The Geosat altimeter was at times able to track over surfaces Seasat could not, but sometimes the acquisition problem was worse. It is observed that Geosat yields denser coverage, but over land Seasat measurements yield a better overall picture of the general topography. It is concluded that the Geosat elevation data set over land can best be utilized to augment the information obtained from the Seasat data and is most useful when investigating topography at scales less than 100 km.

Brenner, A. C.↗

NASA NTRS1989

The GEM-T2 gravitational model

The GEM-T2 is the latest in a series of Goddard Earth Models of the terrestrial field. It was designed to bring modeling capabilities one step closer towards ultimately determining the TOPEX/Poseidon satellite's radial position to an accuracy of 10-cm RMS (root mean square). It also improves models of the long wavelength geoid to support many oceanographic and geophysical applications. The GEM-T2 extends the spherical harmonic field to include more than 600 coefficients above degree 36 (which was the limit for its predecessor, GEM-T1). Like GEM-T1, it was produced entirely from satellite tracking data, but it now uses nearly twice as many satellites (31 vs. 17), contains four times the number of observations (2.4 million), has twice the number of data arcs (1132), and utilizes precise laser tracking from 11 satellites. The estimation technique for the solution has been augmented to include an optimum data weighting procedure with automatic error calibration for the gravitational parameters. Results for the GEM-T2 error calibration indicate significant improvement over previous satellite-only models. The error of commission in determining the geoid has been reduced from 155 cm in GEM-T1 to 105 cm for GEM-T2 for the 36 x 36 portion of the field, and 141 cm for the entire model. The orbital accuracies achieved using GEM-T2 are likewise improved. Also, the projected radial error on the TOPEX satellite orbit indicates 9.4 cm RMS for GEM-T2, compared to 24.1 cm for GEM-T1.

Marsh, J. G.↗

NASA NTRS1990

The GEM-T2 gravitational model

Marsh, J. G.↗

NASA NTRS1969

Survey of man-made electrical noise affecting radio broadcasting

Survey, consisting of limited noise measurements, was made to augment and verify existing data at HF and VHF and to obtain basic data at UHF. Exact frequencies were determined by the absence of intentionally generated signals around three selected frequencies.

Bisignani, W. T.↗

NASA NTRS1975

Radiation belts of Jupiter - A second look

The outbound leg of the Pioneer 11 Jupiter flyby explored a region farther from the equator than that traversed by Pioneer 10, and the new data require modification or augmentation of the magnetodisk model based on the Pioneer 10 flyby. The inner moons of Jupiter are sinks of energetic particles and sometimes sources. A large spike of particles was found near Io. Multiple peaks occurred in the particle fluxes near closest approach to the planet; this structure may be accounted for by a complex magnetic field configuration. The decrease in proton flux observed near minimum altitude on the Pioneer 10 flyby appears attributable to particle absorption by Amalthea.

Fillius, R. W.↗

NASA NTRS1978

Limb Infrared Monitor of the Stratosphere /LIMS/ experiment

The Limb Infrared Monitor of the Stratosphere (LIMS) radiometer is a satellite-borne six-channel multispectral scanning radiometer using a two-stage methane and ammonia solid-cryogen cooler to cool the (Hg, Cd)Te focal plane to 65 K. The LIMS experiment employs thermal IR limb sounding to provide vertical-profile measurement of temperature and of concentrations of O3, NO3, and H2O in the stratosphere on a global scale. The goals of the experiment and the expected accuracies of the measurements are outlined, and the radiance measured by the radiometer is analyzed. A program of correlative measurements designed for verification and augmentation of the LIMS data is discussed. Detailed descriptions are given of the LIMS components and optics, the detector capsule assembly, the solid-cryogen cooler, the four operational modes of the LIMS system, and the data-processor electronics. It is noted that prelaunch acceptance testing thus far completed indicates that the LIMS specification design requirements have been met, and the experiment's performance goals can be achieved.

Drozewski, R. W.↗

NASA NTRS1979

Comparative analysis of PA-31-350 Chieftain (N44LV) accident and NASA crash test data

A full scale, controlled crash test to simulate the crash of a Piper PA-31-350 Chieftain airplane is described. Comparisons were performed between the simulated crash and the actual crash in order to assess seat and floor behavior, and to estimate the acceleration levels experienced in the craft at the time of impact. Photographs, acceleration histories, and the tested airplane crash data is used to augment the accident information to better define the crash conditions. Measured impact parameters are presented along with flight path velocity and angle in relation to the impact surface.

Hayduk, R. J.↗

NASA NTRS1980

Guidelines for the air-sea interaction special study: An element of the NASA climate research program, JPL/SIO workshop report

A program in the area of air sea interactions is introduced. A space capability is discussed for global observations of climate parameters which will contribute to the understanding of the processes which influence climate and its predictability. The following recommendations are some of the suggestions made for air sea interaction studies: (1) a major effort needs to be devoted to the preparation of space based climatic data sets; (2) NASA should create a group or center for climatic data analysis due to the substantial long term effort that is needed in research and development; (3) funding for the analyses of existing data sets should be augmented and continued beyond the termination of present programs; (4) NASA should fund studies in universities, research institutions and governments' centers; and (5) the planning for an air sea interaction mission should be an early task.

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NASA NTRS1983

International Geoscience and Remote Sensing Symposium, Universitaet Muenchen, Munich, West Germany, June 1-4, 1982, Proceedings

The present conference on geoscience and remote sensing considers the multispectral remote sensing of saline seeps, the augmentation of LANDSAT MSS data with topographic data, thematic mapping, the sampling problem in radiation budget studies, aerial conductivity measurements over geothermal areas, a comparison of multifrequency band radars for crop classification, the improved estimation of vegetation-covered soil by combined active/passive microwave remote sensing, and atmospheric water vapor profiling by ground-based radiometry. Also discussed are SAR imaging from an inclined geosynchronous orbit, the classification of agricultural crops in radar images, the Ocean Color Experiment on the second orbital flight test of the Space Shuttle, the dielectric properties of wet materials, remote sensing systems for the mm-wave region, and the simulation of spaceborne stereo radar imagery.

Seiber, A. J.↗

NASA NTRS1991

On the embedding-dimension analysis of AE and AL time series

Several authors have employed the embedding-dimension method to analyze time series of geomagnetic indices, with differing results for the value of the correlation dimension nu. It is argued that these differences may arise from corresponding differences in the length and construction of the various data sets used. Practical application of the method to sets of discretized data requires use of a delay time scale set by the autocorrelation time of the data set. It is found that a particular data set containing 35 days of AE exhibits an autocorrelation time tau(c) longer by an order of magnitude than that of a short-duration (less than 5 days) set, raising the possibility that extant analyses of long-duration sets may have employed delay times shorter than tau(c). In addition, the power spectrum of AE reveals modulation at a period of 24 hr. A numerical experiment on the logistic map shows that such modulation introduces an extra degree of freedom in the data, resulting in an augmented correlation dimension.

Shan, Lin-Hua↗

NASA NTRS1994

Computational study of generic hypersonic vehicle flow fields

The geometric data of the generic hypersonic vehicle configuration included body definitions and preliminary grids for the forebody (nose cone excluded), midsection (propulsion system excluded), and afterbody sections. This data was to be augmented by the nose section geometry (blunt conical section mated with the noncircular cross section of the forebody initial plane) along with a grid and a detailed supersonic combustion ramjet (scramjet) geometry (inlet and combustor) which should be merged with the nozzle portion of the afterbody geometry. The solutions were to be obtained by using a Navier-Stokes (NS) code such as TUFF for the nose portion, a parabolized Navier-Stokes (PNS) solver such as the UPS and STUFF codes for the forebody, a NS solver with finite rate hydrogen-air chemistry capability such as TUFF and SPARK for the scramjet and a suitable solver (NS or PNS) for the afterbody and external nozzle flows. The numerical simulation of the hypersonic propulsion system for the generic hypersonic vehicle is the major focus of this entire work. Supersonic combustion ramjet is such a propulsion system, hence the main thrust of the present task has been to establish a solution procedure for the scramjet flow. The scramjet flow is compressible, turbulent, and reacting. The fuel used is hydrogen and the combustion process proceeds at a finite rate. As a result, the solution procedure must be capable of addressing such flows.

Narayan, Johnny R.↗

NASA NTRS1994

Earth Observing System (EOS)/Advanced Microwave Sounding Unit-A (AMSU-A): Calibration management plan

This is the Calibration Management Plan for the Earth Observing System/Advanced Microwave Sounding Unit-A (AMSU-A). The plan defines calibration requirements, calibration equipment, and calibration methods for the AMSU-A, a 15 channel passive microwave radiometer that will be used for measuring global atmospheric temperature profiles from the EOS polar orbiting observatory. The AMSU-A system will also provide data to verify and augment that of the Atmospheric Infrared Sounder.

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