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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 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Research on recognition of the geologic framework of porphyry copper deposits on ERTS-1 imagery

The author has identified the following significant results. Many new linear and circular features were found. These features prompted novel tectonic classification and analysis especially in the Ray and Ely areas. Tectonic analyses of the Ok Tedi, Tanacross, and Silvertone areas follow conventional interpretations. Circular features are mapped in many cases and are interpreted as exposed or covered intrusive centers. The small circular features reported in the Ok Tedi test area are valid and useful correlations with tertiary intrusion and volcanism in this remote part of New Guinea. Several major faults of regional dimensions, such as the Denali fault in Alaska and the Colorado mineral belt structures in Colorado are detected in the imagery. Many more faults and regional structures are found in the imagery than exist on present maps.

Wilson, J. C.↗
NASA NTRS1980

Characterization of Martian surface materials from earth-based radar - The Memnonia Fossae region

The 1971 and 1973 Goldstone radar data on the Memnonia Fossae region of Mars is used as a test case for the characterization of surface materials. In addition to the discovery of greater relief in the radar-derived topographic measurements of this area than had been inferred from Mariner 9 estimates, and although a tendency for the radar measurements to break down over very rugged terrain has been observed, good correlation is found between radar topography and surface features. Photogeological mapping has identified six surface units which have distinctive radar properties that correlate well with surface features observed in the Viking Orbiter's 10 m/pixel resolution images

Mouginis-Mark, P. J.↗
NASA NTRS1984

Thermal infrared satellite data for the study of tectonic features

Multispectral thermal infrared data from the NOAA-7 Advanced Very High Resolution Radiometer (AVHRR) have been processed to evaluate their potential for mapping tectonic features. Day/night ratio data from 3 thermal bands between 3.7 and 12.0 microns were used to construct a thermal infrared color image that emphasizes heat retention differences in surface materials as a function of wavelength. The study area is an arid region of the Arabian Peninsula where lithologic units are widely exposed to satellite detectors. In spite of the coarse resolution of 1.1 km at nadir, the image of emitted radiation data contains prominent features that appear to relate to fault systems, unmapped extensions of fault systems, and drainage patterns that are lacking in AVHRR reflected radiation data.

Andre, C. G.↗
NASA NTRS2003

A P-band Radar Mission to Mars

Large regions of Mars are covered by dust that obscures geological evidence for fluvial channels, the extent of volcanic flows, and features associated with near-surface ground ice. We describe a Mars orbiting mission carrying a P-band SAR to map these hidden surface features. Mapping would be carried out in HH and VV polarizations, with the comparison of the two expected to yield a distinction between surface echoes and subsurface features beneath up to 5 m of dust. Repeat-pass interferometry data would also be collected to characterize volatile migration at the poles, aeolian shifting of the dust mantle, and possible volcanic deformation. This paper describes the technical design of a P-band SAR for global mapping of Mars, and the characteristics of the proposed mission.

Synthetic Aperture Radar (SAR)↗
NASA NTRS1991

Dynamics of the Ross Ice Shelf

The changing flow of the Ross Ice Shelf is described based on AVHRR data from 18 cloud-free images which evince flow stripes and form the data for a glaciological map. The discharge region of the valley glaciers in the Transantarctic Mountains is found to have curvilinear stripes, and the brightness contrast is enhanced to examine the feature. The map of the region also shows rifts, ridge crests, surface folds, and large-scale lineaments.

Casassa, Gino↗
NASA NTRS1978

LANDSAT survey of near-shore ice conditions along the Arctic coast of Alaska

The author has identified the following significant results. Winter and spring near-shore ice conditions were analyzed for the Beaufort Sea 1973-77, and the Chukchi Sea 1973-76. LANDSAT imagery was utilized to map major ice features related to regional ice morphology. Significant features from individual LANDSAT image maps were combined to yield regional maps of major ice ridge systems for each year of study and maps of flaw lead systems for representative seasons during each year. These regional maps were, in turn, used to prepare seasonal ice morphology maps. These maps showed, in terms of a zonal analysis, regions of statistically uniform ice behavior. The behavioral characteristics of each zone were described in terms of coastal processes and bathymetric configuration.

Stringer, W. J.↗
NASA NTRS1994

Separation of lithospheric, external, and core components of the south polar geomagnetic field at satellite altitudes

We present a new approach to producing scalar Magsat magnetic anomaly maps based on correlation coefficient filtering and the use of almost all of the available orbits. Our method differs from earlier techniques with respect to the following: (1) Passes are selected based on their variance properties rather than planetary indices such as Kp. (2) The core field model is least squares fit to individual passes and subsequently removed instead of substracting the model directly. This technique replaces band pass filtering or polynomial trend removal methods. (3) Each selected pass is sorted geographically and by local time, placed into one of four different altitude bands, and correlation coefficient filtered with the two adjacent passes. The filtering is the second step toward isolating the static lithospheric signal from the more dynamic external field signals. (4) Least squares collocation is used to grid the correlated passes; subsequently, the dawn and dusk maps are also correlation filtered providing another step toward removal of external fields. (5) The four resultant total field maps are continued to a common altitude and again correlation filtered for the static lithospheric anomalies. (6) The filtered results are then averaged together to provide a new total field map of the lithosphere south of 40 deg S latitude. Our total field map differs from previous efforts over the crustal blocks of West Antarctica. We obtained a positive anomaly over Edward VII Peninsula, extending into the Byrd subglacial basin and obtained a negative anomaly over the Ellsworth Mountains and parts of the Byrd subglacial basin. Also, a positive anomaly extending from the Ross Sea to offshore Wilkes Land is present in our map; however, this feature is absent in other maps. Positive anomalies marking the Weddell Sea in previous efforts are not present in our map. Prominent external field anomalies in the quadrant offshore of Wilkes Land are present in all previous efforts; however, these signatures are reduced in our total field map. This map significantly advances efforts for the identification and interpretation of magnetic anomalies of the south polar lithosphere.

Alsdorf, Douglas E.↗
NASA NTRS1974

Evaluation of ERTS-1 data applications to geologic mapping, structural analysis and mineral resource inventory of South America with special emphasis on the Andes Mountain region

The author has identified the following significant results. The La Paz Mosaic and its attendant overlays serve as a model for geologic studies elsewhere in the world. The P.I. and two geologists are mapping the conterminous states at scales of 1:5000,000 and 1:1,000,000. The 1:5 million band 5 mosaic was completed in two days of analysis. The 1:1 million band sheets are being completed at the rate of one per day. Comparison of the preliminary results of the three investigators shows a high correlation of linear and curvilinear features. Comparison with magnetic and gravity data indicates that many features being mapped are deep seated structures that have been active through long periods of geologic time, perhaps dating back to the Precambrian period. A detailed analysis of the El Salvador mining district has been completed. The interpretation is extremely detailed showing a complex pattern of linear features and bedrock outcrop patterns. This is the first product from ERTS-1 to be provided by Chile and shows a high degree of expertise in image interpretation. The Chileans are enthusiastic about their results and are anxious to map the entire country using ERTS.

Carter, W. D.↗
NASA NTRS2013

Joint M3 and Diviner Analysis of the Mineralogy, Glass Composition, and Country Rock Content of Pyroclastic Deposits in Oppenheimer Crater

Here we present our analysis of the near- and mid-infrared spectral properties of pyroclastic deposits within the floor fractured Oppenheimer Crater that are hypothesized to be Vulcanian in origin. These are the first results of our global study of lunar pyroclastic deposits aimed at constraining the range of eruption processes on the Moon. In the near-infrared, we have employed a new method of spectral analysis developed in Horgan et al. (2013) of the 1 m iron absorption band in Chandrayaan-1 Moon Mineralogy Mapper (M3) spectra. By analyzing both the position and shape of the 1 m band we can detect and map the distribution of minerals, glasses, and mixtures of these phases in pyroclastic deposits. We are also using mid-infrared spectra from the Lunar Reconnaissance Orbiter Diviner Lunar Radiometer Experiment to develop ~200 m/pixel Christiansen Feature (CF) maps, which correlate with silica abundance. One of the benefits of using CF maps for analysis of pyroclastic deposits is that they can be used to detect silicic country rock that may have been emplaced by Vulcanian-style eruptions, and are sensitive to iron abundance in glasses, neither of which is possible in the near-infrared. M3 analysis reveals that the primary spectral endmembers are low-calcium pyroxene and iron-bearing glass, with only minor high-calcium pyroxene, and no detectable olivine. The large deposit in the south shows higher and more extensive glass concentrations than the surrounding deposits. We interpret the M3 spectra of the pyroclastic deposits as indicating a mixture of low-calcium pyroxene country rock and juvenile glass, and no significant olivine. Analysis of Diviner CF maps of the Oppenheimer crater floor indicates an average CF value of 8.16, consistent with a mixture of primarily plagioclase and some pyroxene. The average CF values of the pyroclastic deposits range from 8.31 in the SW to 8.24 in the SE. Since CF values within the deposits are as high as 8.49, the lower average CF values of the deposits suggest that each deposit is a mixture of crater floor material and highly mafic juvenile material consistent with either olivine or Fe-bearing pyroclastic glass. Synthesizing our M3 and Diviner results indicates that the crater floor consists of plagioclase with some pyroxene, and the pyroclastic deposits are a mix of this substrate and a glass-rich juvenile material. While we cannot determine the iron content of the glass from M3 spectra alone, the high Diviner CF values suggest that the glass is relatively iron-rich. Indeed, FeO abundances inferred from CF values using the method of Allen et al. (2012) imply that the large southern deposit exhibits a significant enhancement in iron content. This supports our hypothesis that the glass in this deposit is relatively iron-rich.

Bennett, Kristen A.↗
NASA NTRS1993

Linear structures on the small inner satellites of Saturn

Shape modelling methods developed for non-spherical worlds were applied to four satellites of Saturn: Prometheus, Pandora, Janus, and Epimetheus. This results in the first detailed shaded relief maps of their surfaces. Ridges and valleys are described with their implications for satellite history and asteroid 951 Gaspra. They probably result from fracturing during break-up of parent bodies and/or later large impacts. Prometheus and perhaps Gaspra may be coated with debris from parent body fragmentation as well as more recent regolith. These four satellites are covered by relatively few useful images, so the shapes are imperfectly known and positions of features on maps may be wrong by up to a few tens of degrees in some areas (worst where a feature is seen only near a limb). Nevertheless, these shape models are more useful than the previous triaxial ellipsoid models.

Stooke, Philip J.↗
NASA NTRS1974

Skylab radar altimeter - Short-wavelength perturbations detected in ocean surface profiles

Short-wavelength anomalies in sea surface topography, caused by the gravitational effects of major ocean bottom topographic features, have been detected by the radar altimeter aboard Skylab. Some features, such as deep ocean trenches, seamounts, and escarpments, displace the ocean surface by as much as 15 meters over 100-kilometer wavelengths. This experiment demonstrates the potential of satellite altimetry for determining the ocean geoid and for mapping major features of the ocean bottom.

Leitao, C. D.↗
NASA NTRS2001

High-Resolution Large-Field-of-View Three-Dimensional Hologram Display System and Method Thereof

A real-time, dynamic, free space-virtual reality, 3-D image display system is enabled by using a unique form of Aerogel as the primary display media. A preferred embodiment of this system comprises a 3-D mosaic topographic map which is displayed by fusing four projected hologram images. In this embodiment, four holographic images are projected from four separate holograms. Each holographic image subtends a quadrant of the 4(pi) solid angle. By fusing these four holographic images, a static 3-D image such as a featured terrain map would be visible for 360 deg in the horizontal plane and 180 deg in the vertical plane. An input, either acquired by 3-D image sensor or generated by computer animation, is first converted into a 2-D computer generated hologram (CGH). This CGH is then downloaded into large liquid crystal (LC) panel. A laser projector illuminates the CGH-filled LC panel and generates and displays a real 3-D image in the Aerogel matrix.

Chao, Tien-Hsin↗
NASA NTRS1989

Slowly moving thermal features on Jupiter

Maps of the Jovian upper troposphere temperatures derived from Voyager 1 and Voyager 2 infrared interferometer spectrometer (IRIS) spectra show large-scale features which move very slowly. The motion is very different from the inferred local fluid velocity. It is suggested that these features may indicate a deeply-rooted fluid dynamical regime beneath the surface meteorology.

Magalhaes, J. A.↗
NASA NTRS1987

Tectonic domains in the Eastern Hemisphere of Mars

The definition of boundaries of discrete structural provinces on the surface of Mars has previously been made by the assumptions of circular or radial symmetry (in the case of the Tharsis olateau), by artificial quadrangle boundaries for regional studies, or simply by regional geographical features. Much of the planetary structural mapping has been presented in a line or spot format in existing consortium data. Methods are being generated to convert the detailed maps of tectonic features to a format that can be used with standard image processing techniques. In this manner such data can be more readily compared to age and other attributes deduced from geological mapping, gravity results, and topography. The 24 photomosaics covering the Eastern Hemisphere of Mars have already been examined for four types of structural features: erosional remnants, ridges, graben, and scarps. When digitized, each feature was flagged according to feature type, azimuth and length. These values were stored as text files on a quad-by-quad basis for each quad studied.

Maxwell, Ted A.↗
NASA NTRS1999

Recent Advances in Mars Tectonics

Since the publication of the "Stress and Tectonics on Mars" chapter in the Mars book (the last comprehensive summary of our knowledge on the topic) considerable advances have been made in certain areas of Martian tectonics and significant advances are expected with the return of Mars Global Surveyor data. This abstract will summarize the advances in our knowledge of tectonic features and processes on Mars since the Mars book and point towards new areas of research that can be expected from the Mars Global Surveyor data. Two out of three areas of study that were discussed as future directions of work in the Mars chapter have had significant work directed towards them. One area is the field of structural mapping and understanding the timing of tectonic activity on Mars in the framework of the global stratigraphy. Although the general development and relative timing of the development of the Tharsis province on Mars had been understood for some time, actual placement of mapped tectonic features in a global stratigraphic framework has only recently been completed. The second area of study mentioned in the Mars chapter was the impact of improved topography and gravity on modeling loads and deriving stresses in the Martian lithosphere. Mars Global Surveyor is on the brink of returning vastly improved topographic and gravity fields and these newer data sets can be used to better define the size and shape of Tharsis and to quantify loads and derived stresses in the Martian lithosphere. Additional information is contained in the original extended abstract.

Golombek, M. P.↗
NASA NTRS2018

The Next Generation of NASA Rapid Response: Worldview Snapshots

The NASA Rapid Response system started in 2001 by serving static subsets of Near Real Time MODIS (Moderate Resolution Imaging Spectroradiometer) imagery acquired from the Terra satellite. Over this time, Rapid Response has been used to support near real time applications such as wildfire and sea ice mapping for hundreds of thousands of users. In 2011, the toolset expanded to include GIBS, the Global Imagery Browse Services, which provides a web map tiling service of over 700 imagery products, and Worldview (https://worldview.earthdata.nasa.gov/), an interactive web application that showcases the products available in GIBS. This year a new application, Worldview Snapshots, has been added to complete the toolset by providing a flexible, low bandwidth method to download personalized subsets for those who do not need or cannot use a fully featured web mapping application. The original Rapid Response subset tool has been retired and we thank it for its seventeen years of service. Stop by to learn more about the next generation of NASA Rapid Response.

Rapid response system↗
NASA NTRSDate not supplied

Graph Convolutional Network-Strengthened Topic Modeling for Scientific Papers

Machine learning has been woven into statistics to modernize topic modeling over textual documents written in natural language, and scientific paper search and recommendation can consequently offer higher accuracy instead of counting on traditional keyword-based search. However, topic distribution of a paper resulted from existing topic modeling techniques only relies on the statistics of words contained in the paper itself. We argue that community users’ views of a paper may also provide insights at the time of recommendation. For example, if a paper on fake image detection has been cited heavily by machine learning papers, such a feature should be absorbed in the embedding of this paper, so that it can be recommended for future query on machine learning. In this paper, we present a Graph Convolutional Network-strengthened Topic Modeling (GCN-TM) method, which employs GCN technique to refine topic modeling of scientific papers. A citation-oriented knowledge graph is constructed, and topic modeling is mapped to feature embedding of the comprising papers. On top of its own topics carried in its content, each paper learns topics from its neighbors and revise its embedding accordingly. Our empirical studies over real-life scientific literature has proved the necessity and effectiveness of our proposed approach.

Jia Zhang↗
NASA NTRS1973

ERTS-1 imagery use in reconnaissance prospecting: Evaluation of commercial utility of ERTS-1 imagery in structural reconnaissance for minerals and petroleum

The author has identified the following significant results. This study was performed to investigate applications of ERTS-1 imagery in commercial reconnaissance for mineral and hydrocarbon resources. ERTS-1 imagery collected over five areas in North America (Montana; Colorado; New Mexico-West Texas; Superior Province, Canada; and North Slope, Alaska) has been analyzed for data content including linears, lineaments, and curvilinear anomalies. Locations of these features were mapped and compared with known locations of mineral and hydrocarbon accumulations. Results were analyzed in the context of a simple-shear, block-coupling model. Data analyses have resulted in detection of new lineaments, some of which may be continental in extent, detection of many curvilinear patterns not generally seen on aerial photos, strong evidence of continental regmatic fracture patterns, and realization that geological features can be explained in terms of a simple-shear, block-coupling model. The conculsions are that ERTS-1 imagery is of great value in photogeologic/geomorphic interpretations of regional features, and the simple-shear, block-coupling model provides a means of relating data from ERTS imagery to structures that have controlled emplacement of ore deposits and hydrocarbon accumulations, thus providing a basis for a new approach for reconnaissance for mineral, uranium, gas, and oil deposits and structures.

Saunders, D. F.↗