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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 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Gravity anomaly detection: Apollo/Soyuz

The Goddard Apollo-Soyuz Geodynamics Experiment is described. It was performed to demonstrate the feasibility of tracking and recovering high frequency components of the earth's gravity field by utilizing a synchronous orbiting tracking station such as ATS-6. Gravity anomalies of 5 MGLS or larger having wavelengths of 300 to 1000 kilometers on the earth's surface are important for geologic studies of the upper layers of the earth's crust. Short wavelength Earth's gravity anomalies were detected from space. Two prime areas of data collection were selected for the experiment: (1) the center of the African continent and (2) the Indian Ocean Depression centered at 5% north latitude and 75% east longitude. Preliminary results show that the detectability objective of the experiment was met in both areas as well as at several additional anomalous areas around the globe. Gravity anomalies of the Karakoram and Himalayan mountain ranges, ocean trenches, as well as the Diamantina Depth, can be seen. Maps outlining the anomalies discovered are shown.

Vonbun, F. O.↗
NASA NTRS1976

Geodynamics experiment MA-128

The Apollo Soyuz Test Project Geodynamics Experiment was performed to assess the feasibility of tracking and recovering high frequency components of the earth gravity field by utilizing a synchronous orbiting tracking station such as Applications Technology Satellite 6. Two prime areas of data collection were selected for this experiment. The first area is the center of the African continent, and the second area is the Indian Ocean depression centered at latitude 5 N and longitude 75 E. Preliminary results show that the detectability objective of the experiment has been achieved in both areas as well as in several additional anomalous areas around the globe. Gravity anomalies of the Karakoram and Himalayan mountain ranges of ocean trenches, and of the Diamantina depth are specific examples.

Vonbun, F. O.↗
NASA NTRS1977

Fast, accurate rangefinder

Computer-controlled optical ranging system detects objects as close as 1m and as distant as 30m. Originally developed for robot planetary-surface exploration, system is applicable to vehicular obstacle avoidance, surveying, remote manipulator operation, and other applications.

Johnston, A. R.↗
NASA NTRS1979

Low-level processing for real-time image analysis

A system that detects object outlines in television images in real time is described. A high-speed pipeline processor transforms the raw image into an edge map and a microprocessor, which is integrated into the system, clusters the edges, and represents them as chain codes. Image statistics, useful for higher level tasks such as pattern recognition, are computed by the microprocessor. Peak intensity and peak gradient values are extracted within a programmable window and are used for iris and focus control. The algorithms implemented in hardware and the pipeline processor architecture are described. The strategy for partitioning functions in the pipeline was chosen to make the implementation modular. The microprocessor interface allows flexible and adaptive control of the feature extraction process. The software algorithms for clustering edge segments, creating chain codes, and computing image statistics are also discussed. A strategy for real time image analysis that uses this system is given.

Eskenazi, R.↗
NASA NTRS1980

AMTV headway sensor and safety design

A headway sensing system for an automated mixed traffic vehicle (AMTV) employing an array of optical proximity sensor elements is described, and its performance is presented in terms of object detection profiles. The problem of sensing in turns is explored experimentally and requirements for future turn sensors are discussed. A recommended headway sensor configuration, employing multiple source elements in the focal plane of one lens operating together with a similar detector unit, is described. Alternative concepts including laser radar, ultrasonic sensing, imaging techniques, and radar are compared to the present proximity sensor approach. Design concepts for an AMTV body which will minimize the probability of injury to pedestrians or passengers in the event of a collision are presented.

Johnston, A. R.↗
NASA NTRS1983

Focal-Plane-Array Optical Proximity Sensors

Objects detected at beam axis intersections. Group of light sources or detectors is mounted in box at focal plane of lens. Box can therefore illuminate or view several axes, each corresponding to source or detector of group. Proximity sensing system developed to trigger braking system of automatically controlled car.

Johnston, A. R.↗
NASA NTRS1985

Video image processing

Current technology projections indicate a lack of availability of special purpose computing for Space Station applications. Potential functions for video image special purpose processing are being investigated, such as smoothing, enhancement, restoration and filtering, data compression, feature extraction, object detection and identification, pixel interpolation/extrapolation, spectral estimation and factorization, and vision synthesis. Also, architectural approaches are being identified and a conceptual design generated. Computationally simple algorithms will be research and their image/vision effectiveness determined. Suitable algorithms will be implimented into an overall architectural approach that will provide image/vision processing at video rates that are flexible, selectable, and programmable. Information is given in the form of charts, diagrams and outlines.

Murray, N. D.↗
NASA NTRS1987

The nearby Abell clusters. II - Luminosity and spatial distribution of galaxies in A2175, A2256, and A2384

The luminosity and spatial distributions of galaxies in the nearby Abell clusters A2175, A2256, and A2384 have been studied using an automated object detection, classification, and photometry system. Schecter functions have been fit to the observed luminosity functions of these clusters. Values of the characteristic magnitude Mr(asterisk) at the 'break' in the luminosity function (LF) are found that are within about 0.25 mag of the so-called 'universal' value of Mr(asterisk) for A2256 and A2384. The faint ends of the LFs of these two clusters are fairly flat, with a value of -1.6 that is steeper than the universal value of -1.25. The spatial distributions of galaxies in all three clusters seem to be described fairly well by power laws, with no evidence for constant-density cores, when the cluster center is assumed to be the central D or cD galaxy. These results indicate a strong correlation between the density distribution of galaxies and the presence of a dominant D or cD galaxy in the cluster.

Oegerle, William R.↗
NASA NTRS1988

The progenitor of SN 1987A

IUE observations of the stars seen in plates of the SN 1987A region are examined as possible progenitors of the supernova. The identity and characteristics of the stars are discussed. Evidence is presented, which demonstrates that the objects detected near SN 1987A were Stars 2 and 3. Star 1 (Sk -69 deg 202) is not present in IUE spectra of the supernova. It is concluded that Sk -69 deg 202 is the star which exploded.

Sonneborn, G.↗
NASA NTRS1989

Force/torque and tactile sensors for sensor-based manipulator control

The autonomy of manipulators, in space and in industrial environments, can be dramatically enhanced by the use of force/torque and tactile sensors. The development and future use of a six-component force/torque sensor for the Hermes Robot Arm (HERA) Basic End-Effector (BEE) is discussed. Then a multifunctional gripper system based on tactile sensors is described. The basic transducing element of the sensor is a sheet of pressure-sensitive polymer. Tactile image processing algorithms for slip detection, object position estimation, and object recognition are described.

Vanbrussel, H.↗
NASA NTRS1991

A luminous X-ray binary in M82

Optical CCD imaging at the position of a bright X-ray point source just off the visible disk of the nearby irregular galaxy M82 constrain it to be an X-ray binary with a 0.2-4 keV X-ray luminosity of not less than 9 x 10 exp 38 ergs/sec. Assuming that the X-ray emission is due to a single object, then by asumming an Eddington limit appropriate for pure electron scattering, this luminosity requires a minimum primary mass of not less than 15 solar masses; thus, this X-ray source is a black hole candidate. If the brightest optical object detected inside the X-ray error circle at B about 22.2 is the secondary to the X-ray emitter, it is most likely an early type star making this system the most luminous massive X-ray binary system known.

Stocke, John T.↗
NASA NTRS1993

Observations of 3C 273 with the Goddard High Resolution Spectrograph on the Hubble Space Telescope

The observations of the quasar 3C 273 taken with the Goddard High Resolution Spectrograph in 1991 February are presented here. We have included both the reduced raw data, and smoothed and deconvolved spectra. Also, a list of observed absorption lines is presented. The data comprise 11 spectra, including one low resolution and 10 medium resolution observations. The wavelength region covered ranged from about 1150 to 2820 A, but was not all inclusive. The procedures used to obtain and reduce the data, including corrections for fixed pattern noise, compensation for the effects of spherical aberration in the HST primary mirror, and objective detection of weak absorption lines, are described. We also have included a short discussion on the detection of galactic Ni II and Virgo cluster metal lines.

Brandt, J. C.↗
NASA NTRS1992

History of on-orbit satellite fragmentations

Since the first serious satellite fragmentation occurred in Jun. 1961, and instantaneously increased the total Earth satellite population by more than 400 percent, the issue of space operations within the finite region of space around the Earth has been the subject of increasing interest and concern. The prolific satellite fragmentations of the 1970's and the marked increase in the number of fragmentations in the 1980's served to widen international research into the characteristics and consequences of such events. Plans for large, manned space stations in the next decade and beyond demand a better understanding of the hazards of the dynamic Earth satellite population. The contribution of satellite fragmentations to the growth of the Earth satellite population is complex and varied. The majority of detectable fragmentation debris have already fallen out of orbit, and the effects of 40 percent of all fragmentations have completely disappeared. In this volume, satellite fragmentations are categorized by their assessed nature and to a lesser degree by their effect on the near-Earth space environment. A satellite breakup is the usually destructive disassociation of an orbital payload, rocket body, or structure, often with a wide range of ejecta velocities. A satellite breakup may be accidental or the result of intentional actions, e.g., due to a propulsion system malfunction or a space weapons test, respectively. An anomalous event is the unplanned separation, usually at low velocity, of one or more detectable objects from a satellite which remains essentially intact. Anomalous events can be caused by material deterioration of items such as thermal blankets, protective shields, or solar panels. As a general rule, a satellite breakup will produce considerably more debris, both trackable and non-trackable, than an anomalous event. From one perspective, satellite breakups may be viewed as a measure of the effects of man's activity on the environment, while anomalous events may be a measure of the environment on man-made objects.

Nauer, David J.↗
NASA NTRS1994

Multivariate statistical analysis software technologies for astrophysical research involving large data bases

We developed a package to process and analyze the data from the digital version of the Second Palomar Sky Survey. This system, called SKICAT, incorporates the latest in machine learning and expert systems software technology, in order to classify the detected objects objectively and uniformly, and facilitate handling of the enormous data sets from digital sky surveys and other sources. The system provides a powerful, integrated environment for the manipulation and scientific investigation of catalogs from virtually any source. It serves three principal functions: image catalog construction, catalog management, and catalog analysis. Through use of the GID3* Decision Tree artificial induction software, SKICAT automates the process of classifying objects within CCD and digitized plate images. To exploit these catalogs, the system also provides tools to merge them into a large, complete database which may be easily queried and modified when new data or better methods of calibrating or classifying become available. The most innovative feature of SKICAT is the facility it provides to experiment with and apply the latest in machine learning technology to the tasks of catalog construction and analysis. SKICAT provides a unique environment for implementing these tools for any number of future scientific purposes. Initial scientific verification and performance tests have been made using galaxy counts and measurements of galaxy clustering from small subsets of the survey data, and a search for very high redshift quasars. All of the tests were successful, and produced new and interesting scientific results. Attachments to this report give detailed accounts of the technical aspects for multivariate statistical analysis of small and moderate-size data sets, called STATPROG. The package was tested extensively on a number of real scientific applications, and has produced real, published results.

Djorgovski, S. George↗
NASA NTRS1994

Multivariate Statistical Analysis Software Technologies for Astrophysical Research Involving Large Data Bases

We developed a package to process and analyze the data from the digital version of the Second Palomar Sky Survey. This system, called SKICAT, incorporates the latest in machine learning and expert systems software technology, in order to classify the detected objects objectively and uniformly, and facilitate handling of the enormous data sets from digital sky surveys and other sources. The system provides a powerful, integrated environment for the manipulation and scientific investigation of catalogs from virtually any source. It serves three principal functions: image catalog construction, catalog management, and catalog analysis. Through use of the GID3* Decision Tree artificial induction software, SKICAT automates the process of classifying objects within CCD and digitized plate images. To exploit these catalogs, the system also provides tools to merge them into a large, complex database which may be easily queried and modified when new data or better methods of calibrating or classifying become available. The most innovative feature of SKICAT is the facility it provides to experiment with and apply the latest in machine learning technology to the tasks of catalog construction and analysis. SKICAT provides a unique environment for implementing these tools for any number of future scientific purposes. Initial scientific verification and performance tests have been made using galaxy counts and measurements of galaxy clustering from small subsets of the survey data, and a search for very high redshift quasars. All of the tests were successful and produced new and interesting scientific results. Attachments to this report give detailed accounts of the technical aspects of the SKICAT system, and of some of the scientific results achieved to date. We also developed a user-friendly package for multivariate statistical analysis of small and moderate-size data sets, called STATPROG. The package was tested extensively on a number of real scientific applications and has produced real, published results.

Djorgovski, S. G.↗
NASA NTRS1994

NIFTE: The Near Infrared Faint-Object Telescope Experiment

The high sensitivity of large format InSb arrays can be used to obtain deep images of the sky at 3-5 micrometers. In this spectral range cool or highly redshifted objects (e.g. brown dwarfs and protogalaxies) which are not visible at shorter wavelengths may be observed. Sensitivity at these wavelengths in ground-based observations is severly limited by the thermal flux from the telescope and from the earth's atmosphere. The Near Infrared Faint-Object Telescope Experiment (NIFTE), a 50 cm cooled rocket-borne telescope combined with large format, high performance InSb arrays, can reach a limiting flux less than 1 micro-Jy(1-sigma) over a large field-of-view in a single flight. In comparison, the Infrared Space Observatory (ISO) will require days of observation to reach a sensitivity more than one order of magnitude worse over a similar area of the sky. The deep 3-5 micrometer images obtained by the rocket-borne telescope will assist in determining the nature of faint red objects detected by ground-based telescopes at 2 micrometers, and by ISO at wavelengths longer than 5 micrometers.

Bock, James J.↗
NASA NTRS1993

X-ray emission from a complete sample of Abell clusters of galaxies

The ROSAT All-Sky Survey (RASS) is used to investigate the X-ray properties of a complete sample of Abell clusters with measured redshifts and accurate positions. The sample comprises the 145 clusters within a 561 square degree region at high galactic latitude. The mean redshift is 0.17. This sample is especially well suited to be studied within the RASS since the mean exposure time is higher than average and the mean galactic column density is very low. These together produce a flux limit of about 4.2 x 10(exp -13) erg/sq cm/s in the 0.5 to 2.5 keV energy band. Sixty-six (46%) individual clusters are detected at a significance level higher than 99.7% of which 7 could be chance coincidences of background or foreground sources. At redshifts greater than 0.3 six clusters out of seven (86%) are detected at the same significance level. The detected objects show a clear X-ray luminosity -- galaxy count relation with a dispersion consistent with other external estimates of the error in the counts. By analyzing the excess of positive fluctuations of the X-ray flux at the cluster positions, compared with the fluctuations of randomly drawn background fields, it is possible to extend these results below the nominal flux limit. We find 80% of richness R greater than or = 0 and 86% of R greater than or = 1 clusters are X-ray emitters with fluxes above 1 x 10(exp -13) erg/sq cm/s. Nearly 90% of the clusters meeting the requirements to be in Abell's statistical sample emit above the same level. We therefore conclude that almost all Abell clusters are real clusters and the Abell catalog is not strongly contaminated by projection effects. We use the Kaplan-Meier product limit estimator to calculate the cumulative X-ray luminosity function. We show that the shape of the luminosity functions are similiar for different richness classes, but the characteristic luminosities of richness 2 clusters are about twice those of richness 1 clusters which are in turn about twice those of richness 0 clusters. This result is another manifestation of the luminosity -- richness elation for Abell clusters.

Briel, Ulrich G.↗
NASA NTRS1995

Imaging Magnetometer

Imaging magnetometer proposed for scientific, industrial, or military use in detecting underground structures containing magnetic materials and underground machines generating and/or altering magnetic fields. Includes electron-beam tube integrated with phosphor-coated charge-coupled device (CCD). Images formed by magnetic deflection of electron beam. Locations, magnitudes, and directions of identifiable features of magnetic field examined to extract data on locations, sizes, and types of magnetically detected objects.

Moynihan, Philip I.↗