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At least 739 records · Page 41
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

OAO-2 observations of beta Lyrae and a provisional interpretation

Six-color ultraviolet photoelectric observations of beta Lyrae obtained with OAO-2 are presented. These observations, made at 1380, 1500, 1920, 2460, 2980 and 3330 A, represent the first truly continual coverage of the light changes of beta Lyrae during one orbital revolution and were obtained in November 1970. The photometric data are supplemented by spectral scans in the wavelength intervals 3800-1800 A and 2000-1050 A; the latter interval was scanned at 10 A resolution once during every OAO-2 orbit, i.e., about 100 minutes. Anomalous features, such as asymmetries and short and long term variations, are present in the light curves. A tentative discussion of solutions of the light curves is given.

Kondo, Y.↗
NASA NTRS1990

The intensity dependent spread model and color constancy

Odetics is investigating the use of the intensity dependent spread (IDS) model for determining color constancy. Object segmentation is performed effortlessly by the human visual systems, but creating computer vision that takes an image as input and performs object identification on the basis of color has some difficulties. The unknown aspects of the light illuminating a scene in space or anywhere can seriously interfere with the use of color for object identification. The color of an image depends not only on the physical characteristics of the object, but also on the wavelength composition of the incident illumination. IDS processing provides the extraction of edges and of reflectance changes across edges, independent of variations in scene illumination. IDS depends solely on the ratio of the reflectances on the two sides of the edge. Researchers are in the process of using IDS to recover the reflectance image.

Kurrasch, Ellie↗
NASA NTRS2003

Package for Interactive Analysis of Line Emission (Analysis of UV-X-Ray High-Resolution Emission Spectra)

PINTofALE is an IDL based package to analyze high-resolution grating spectra. The first version was made available to the public on 3 February 2001. Since then we have carried out numerous changes, and the current release is version 1.5, released on 9 October 2002. The changes include upgrades to handle higher versions of IDL, the new version of the CHIANTI database (v4), major enhancements in user-friendliness, improved handling of response matrices, the ability to handle 24-bit color, access to the Atomic Plasma Emission Database (APED), and beta releases of Markov Chain Monte Carlo (MCMC) based DEM fitting routines. Plans for the future include: inclusion of MCMC techniques in the fitting programs, enhanced graphics capabilities, an overhaul of the line and continuum database structure, and bug fixes. In September 2002, we hired a data analyst (LiWei Lin) to work on PINTofALE. Mr.Lin is concentrating on incorporating MCMC as well as simpler Monte-Carlo techniques, fast RMF convolution, etc., into the code base, as well as reviewing the existing documentation and searching for bugs. A detailed description of the package, together with fairly detailed documentation, example walks-throughs, and downloadable tar files, are available on-line from http://hea-www. harvard.edu/PINTofALE/

Kashyap, Vinay↗
NASA NTRSDate not supplied

Using Earth Observations to Analyze Shoreline Changes and Understand the Effects of Sea Level Rise in Southern Puerto Rico

This summer, the Jobos Bay National Estuarine Research Reserve (JBNERR) partnered with NASA DEVELOP to evaluate water quality, mangrove forest extent, sea level rise, and land cover changes in Jobos Bay. DEVELOP is a national capacity building program that connects satellite data with early career scientists and decision makers. Through ten-week feasibility studies, DEVELOP partners with organizations that have the power to enact policy within their communities. Jobos Bay, in the southeast coast of Puerto Rico, has experienced intense hurricane seasons with increased seasonal storm surge, near-shore land use changes, and strong variations in precipitation and runoff. Through proposals, bi-weekly meetings, and frequent email communication, this cross-sector initiative provided valuable results for management decisions within the reserve. Using satellite observations to measure land use change, the team found that 17% of the reserve has shifted from land to water along the coast since 1997. Using Sentinel-2 the team was able to visualize turbidity, chlorophyll-a, and colored dissolved organic matter (CDOM) for Jobos Bay. While some large events such as Hurricane Maria were reflected in the turbidity analysis, chlorophyll-a and CDOM visualizations were limited by the influence of shallow-water bottom reflectance, particularly around reefs and within the Bay. The team also found that Jobos Bay lost 4.9 square kilometers of mangrove habitat over the past decade, calculated using Landsat 7 and 8 within Google Earth Engine. The results from this study will inform JBNERR and its community members on the regional impacts of sea level rise as well as serve as a baseline for future conservation efforts and research in the estuary.

Olivia Spencer↗
NASA NTRS1969

Vegetation changes caused by fire in the Florida flatwoods as observed by remote sensing

The nature of the flatwoods and the role that ground fires have played in maintaining them are discussed. Emphasis is placed on the areal and temporal extent of burns as recorded uniformly by remote sensors. Thermal infrared, color infrared, and Ektachrome imagery were obtained from sensors flown by a NASA aircraft at 15,000 feet over a test site in Osceola County, Florida, in March 1968. The overall pattern of burning can be sequenced and mapped uniformly from the imagery. By comparing the various imagery, areal and temporal extent of burned areas can be determined. It was concluded that remote sensed imagery provides more accurate and areally comprehensive media for assessing the impact of ground fires on the landscape of the flatwoods region than are available from any other data source.

Mealor, W. T., Jr.↗
NASA NTRS1982

Magnetic changes accompanying the thermal decomposition of nontronite /in air/ and its relevance to Martian mineralogy

It is found that the thermal treatment of nontronite in air, for long periods at 700 C or short periods at 900 C, results in the destruction of the nontronite structure, a distinct reddening in color, and a large increase in magnetic susceptibility and saturation magnetization. Measurements and calculations of the magnetic properties suggest that the magnetism is due to the presence of ultrafine particles of alpha or gamma Fe2O3. The highly magnetic thermally treated nontronite is amorphous to X-rays consistent with an ultrafine grain size. Prolonged heating results in the growth of alpha Fe2O3, while reflectivity spectra of a sample heated for 1 hr at 900 C indicate the presence of an opaque, magnetite-like phase in addition to alpha Fe2O3. It is found that the thermally treated nontronite has chemical, color, and magnetic properties similar to those found by Viking on Mars. It is concluded that these results indicate an origin for the fine grained Martian surface material by repeated impacts into an Fe-rich smectite-charged regolith (Weldon et al., 1980).

Moskowitz, B. M.↗
NASA NTRS1990

Wide-angle astrometry with the Mark III stellar interferometer

Astrometric measurements made with the Mark III stellar interferometer on five nights in August-September 1988 yielded average formal 1-sigma errors for 12 FK5 stars of 6 mas in declination and 10 mas in right ascension. This improvement in precision over previously reported measurements with this instrument made in 1986 is attributable to several factors: a second 12 m baseline; oriented E-S, was added to the instrument to improve the determination of right ascension; two-color analysis was included in the data-reduction process, along with a new central-fringe identification algorithm using three spectral channels, in order to reduce atmospheric errors; thermal control was greatly improved; and changes were made to observational procedures and hardware to monitor variations in the delay offset due to residual thermal drifts. Approximately half of the new positions are within 50 mas of their FK5 positions. However, an extended series of measurements are needed to ascertain the accuracy that can be achieved by interferometry.

Shao, M.↗
NASA NTRS2004

The Chandra Large Area Synoptic X-ray Survey (CLASXS) of the Lockman Hole-Northwest: The X-ray Catalog

We present the X-ray catalog and basic results from our Chandra Large Area Synoptic X-ray Survey (CLASXS) of the Lockman Hole-Northwest field. Our 9 ACIS-I fields cover a contiguous solid angle of approx. 0.4 sq deg and reach fluxes of 5 x 10(exp -16) ergs/sq cm/s (0.4-2 keV) and 3 x 10(exp -15) ergs/sq cm/s (2-8 keV). Our survey bridges the gap between ultradeep pencil-beam surveys, such as the Chandra Deep Fields (CDFs), and shallower, large area surveys, allowing a better probe of the X-ray sources that contribute most of the 2-10 keV cosmic X-ray background (CXB). We find a total of 525 X-ray point sources and 4 extended sources. At approx. 10(exp -14)ergs/sq cm/s (2-8 keV), our number counts are significantly higher than those of several non-contiguous, large area surveys. Such a large difference is an indication of clustering in the X-ray sources. On the other hand, the integrated flux from the CLASXS field, combined with ASCA and Chandra ultradeep surveys, is consistent with results from other large area surveys, within the variance of the CXB. We see spectral evolution in the hardening of the sources at fluxes below 10(exp -14) ergs/sq cm/s, which agrees with previous observations from Chandra and XMM-Newton. About 1/3 of the sources in the CLASXS field have multiple observations, allowing variability tests. Above 4 x 10(exp -14) ergs/sq cm/s (0.4-8 keV), approx. 61% of the sources are variable. We also investigated the spectral variability of the variable sources. While most show spectral softening with increasing flux, or no significant spectral change, there are a few sources that show a different trend. Four extended sources in CLASXS is consistent with the previously measured LogN-LogS of galaxy clusters. Using X-ray spectra and optical colors, we argue that 3 of the 4 extended sources are galaxy clusters or galaxy groups. We report the discovery of a gravitational lensing arc associated with one of these sources. Using red sequence and brightest cluster galaxy methods, we find that the redshifts of the extended sources are in the range z approx. 0.5 - 1. The inferred masses within the Einstein radii are consistent with the mass profiles of local groups scaled to the same virial radii.

Yang, Y.↗
NASA NTRS1973

In situ spectroradiometric quantification of ERTS data

The task of correlating in situ spectral reflectance measurements with ERTS imagery has commenced. A method of additive color analysis of a single multispectral band taken on different dates indicates that ERTS-1 bulk images have sufficient spatial and spectral fidelity to show indications of the presence of soil moisture in desert playas and changes in soil moisture with time. The chain of causality between soil moisture, in situ spectral reflectance, and ERTS multispectral scanner image density remains to be established during the subsequent phases of this study.

Yost, E.↗
NASA NTRS1974

Experiment to evaluate feasibility of utilizing Skylab-EREP remote sensing data for tectonic analysis of the Bighorn Mountains region, Wyoming-Montana

The author has identified the following significant results. Analysis of SL-3, S-190A, and S-190B color frames indicates two sets of linears obliquely cutting across the east-west trending Owl Creek-Bridger uplifts. A northwest set of faults and folds has been mapped previously but the imagery indicates some changes and addition of detail can be made. A less pronounced east-northeast set of linear alignments (drainage segments, lithologic contacts, possible faults) extends into the southeast part of the Big Horn Basin.

Hoppin, R. A.↗
NASA NTRS1980

A project to evaluate moisture stress in corn and soybean areas of western and southwestern Minnesota

Remote sensing techniques, particularly LANDSAT data, were used to assess soil moisture stress through crop signature in southwestern Minnesota. Related objectives were: localization of droughty, well drained, and poorly drained soils; detection of stress from hail, wind, and disease damage; and the use of remote sensing data for agricultural management. Since the amount and distribution of precipitation were adequate during the 1977 and 1978 growing seasons, no significant stress occurred. Crop conditions were very favorable. As a result, crop signatures were too uniform to reflect soilscape variations and crop condition changes. In 1979 precipitation was again adequate to excess, particularly in June and August. In some cases, poorly drained sites especially, stress conditions developed as a result of excess of water and could be identified on color infrared photographs.

Rust, R. H.↗
NASA NTRS1989

A few modeling and rendering techniques for computer graphics and their implementation on ultra hardware

Ultra network is a recently installed very high speed graphic hardware at NASA Langley Research Center. The Ultra Network interfaced to Voyager through its HSX channel is capable of transmitting up to 800 million bits of information per second. It is capable of displaying fifteen to twenty frames of precomputed images of size 1024 x 2368 with 24 bits of color information per pixel per second. Modeling and rendering techniques are being developed in computer graphics and implemented on Ultra hardware. A ray tracer is being developed for use at the Flight Software and Graphic branch. Changes were made to make the ray tracer compatible with Voyager.

Bidasaria, Hari↗
NASA NTRS1992

The timescales of the optical variability of blazars. III - OJ 287 and BL Lacertae

The BL Lacertae objects OJ 287 and BL Lac have been photometrically monitored in an effort to study the nature of optical variations which may occur on timescales ranging from years to less than a day. The results of ten years of photometric monitoring of these two objects show variations which are consistent with those reported by other authors. No strong dependence of color with source brightness was detected, although both sources exhibited a weak tendency to be bluer when brighter. Microvariability was observed for both objects; variations as large as 0.1 mag/hr were observed for BL Lac and changes as large as 0.08 mag/hr were observed for OJ 287. No evidence for a periodicity was found in the observed variations of either object.

Carini, M. T.↗
NASA NTRS1993

Lunar impact basins: New data for the nearside northern high latitudes and eastern limb from the second Galileo flyby

During the December 1992 Galileo Earth/Moon encounter the northern half of the nearside, the eastern limb, and parts of the western farside of the Moon were illuminated and in view, a geometry that was complementary to the first lunar encounter in December, 1990, which obtained images of the western limb and eastern farside. The Galileo Solid State Imaging System (SSI) obtained multispectral images for these regions during the second encounter and color ratio composite images were compiled using combinations of band ratios chosen on the basis of telescopic spectra and laboratory spectra of lunar samples. Ratios of images taken at 0.41 and 0.76 micron are sensitive to changes in the slope in the visible portion of the spectrum, and ratios of 0.99 and 0.76 micron relate to the strength of near-infrared absorptions due to iron-rich mafic minerals (0.76/0.99 ratio) such as olivine and pyroxene. Results of the analyses of the compositional diversity of the crust, maria, and Copernican craters are presented elsewhere. Primary objectives for lunar basin analysis for the second encounter include analysis of: the north polar region and the Humboldtianum basin; the characteristics of the Imbrium basin along its northern border and the symmetry of associated deposits; the origin of light plains north of Mare Frigoris and associated with several other basins; the nature and significance of pre-basin substrate; the utilization of the stereo capability to assess subtle basis structure; the identification of previously unrecognized ancient basins; basin deposits and structure for limb and farside basins; and assessment of evidence for proposed ancient basins. These data and results will be applied to addressing general problems of evaluation of the nature and origin of basin deposits, investigation of mode of ejecta emplacement and ejecta mixing, analysis of the origin of light plains deposits, analysis of basin deposit symmetry/asymmetry, investigation of basin depth of excavation and crustal stratigraphy, and assessment of models for basin formation and evolution. Here we discuss some preliminary results concerning lunar impact basins, their deposits, and prebasin substrates, using the same approaches that we employed for the Orientale and South Pole-Aitken basins using the data from the first encounter.

Head, J. W.↗
NASA NTRS1995

Visualization of the electrostatic potential distribution in both polar ionospheres using multiple satellite measurements

During the time from December 1991 through March 1992, there were four operational DMSP satellites in polar orbit. All four satellites carried the Special Sensor-Ions, Electrons, Scintillation (SSIES) plasma package which included an ion drift meter. Data from the drift meter, combined with the magnetic field data, allowed the calculation of the electrostatic potential in the ionosphere along the satellite's path. Simultaneous polar coverage by four satellites was unprecedented, providing researchers with almost continuous monitoring of the potential distribution in both hemispheres for the four month period. Combining the magnitude and location of the potential data from each of the four satellites in order to examine the varying potential distribution pattern in both hemispheres presented a major challenge in data visualization. The problem was solved by developing a three-dimensional presentation of the data where the potentials are color coded and represented by the vertical dimension. This paper presents examples from a computer animation of several days of data demonstrating evolution of the size and shape of the potential distribution, along with how these changes correspond to variations in other geophysical parameters, such as the IMF orientation and the K(sub p) index.

Hairston, Marc R.↗
NASA NTRS2018

Predicting Rapid Fire Growth (Flashover) Using Generative Adversarial Networks

A flashover occurs when a fire spreads very rapidly through crevices due to intense heat. Flashovers present one of the most frightening and challenging fire phenomena to those who regularly encounter them: firefighters. Firefighters’ safety and lives often depend on their ability to predict flashovers before they occur. Typical pre-flashover fire characteristics include dark smoke, high heat, and rollover (“angel fingers”) and can be quantified by color, size, and shape. Using a color video stream from a firefighter’s body camera, we applied generative adversarial neural networks for image enhancement. The neural networks were trained to enhance very dark fire and smoke patterns in videos and monitor dynamic changes in smoke and fire areas. Preliminary tests with limited flashover training videos showed that we predicted a flashover as early as 55 seconds before it occurred.

Lu, Thomas↗
NASA NTRS2021

Florida Transportation and Infrastructure: Monitoring Water Quality Along Southern Florida Seaports to Assess Impact on Coral Reef Tracts from Harbor Deepening Projects

The U.S. Army Corps of Engineers (USACE) and National Oceanic and Atmospheric Administration (NOAA) National Marine Fisheries Service (NMFS) will be supervising a harbor deepening project in Port Everglades, Florida. The project raises concerns about potential impacts on the nearby Florida reef tract through increased turbidity and sediment from the dredging. To better understand these potential impacts, the NASA DEVELOP team created an interactive Google Earth Engine tool to help establish a historical baseline of water quality parameters and assist monitoring these parameters more frequently than traditional sampling. This Seaport & Harbor Area Resource Quality (SHARQ) tool incorporates remotely sensed data from Sentinel-2 Multispectral Instrument, Landsat 5 Thematic Mapper, Landsat 7 Enhanced Thematic Mapper+, Landsat 8 Operational Land Imager, and Aqua Moderate Resolution Imaging Spectroradiometer. It allows users to view true color images and calculate water quality parameters, like turbidity and chlorophyll-a, for any given study area and time period from 1984 onward. The SHARQ tool also generate time series charts, allowing users to interpret changes in water quality over a given time range. The accuracy of the remotely sensed water quality parameter algorithms was determined using in situ data to calculate percent difference and root mean square error values (RMSE), which ranged from 0.32 to 0.58 error between sites. Using the SHARQ tool’s time series analysis feature, a baseline average turbidity metric of ~6.8 FNUs provides a historical baseline average for turbidity between September 2000 and 2020 and can assist in future decision-making for determining thresholds for turbidity.

Benjamin Rocha↗
NASA NTRSDate not supplied

Spaceflight Autonomous Multigenerational Microbial Sequencer in Support of Plant-Growth Systems

The CubeSat platform has proven successful in obtaining meaningful life science information when biological payloads are incorporated. Examples include: 1) the first-ever CubeSat with a biological payload, GeneSat-1, which demonstrated decreased growth rates for flight samples of Escherichia coli in low Earth orbit (Parra et al. 2008); 2) PharmaSat, demonstrated that Saccharomyces cerevisiae in the microgravity environment exhibits a significant level of metabolic activity even at high doses of applied antifungal (Ricco et al. 2011); 3) O/OREOS, which used Bacillus subtilis(bacteria) to demonstrate for the first time that microorganisms can be loaded in a dried, dormant form and then rehydrated and grown in orbit months after launch (Nicholson et al. 2011; Ehrenfreund et al. 2014; 4) the SporeSat payload, which investigated Ceratopteris richardii(fern spores) using lab-on-a-chip devices (BioCDs) and minicentrifuges to produce artificial gravitational forces in ground studies (Park et al. 2017), with demonstration of the BioCD and minicentrifuge in space; 5) EcAMSat, the first CubeSat to be directly deployed from the ISS for an experiment assessing antibiotic resistance of E. coli in the microgravity environment (Padgen et al. 2020); 6) BioSentinel, exposed a culture of yeast to galactic cosmic radiation (GCR) and solar particle events while in heliocentric orbit to measure the rate of double-strand-break repair using DNA-repair-deficient mutants. This effort measures the metabolic parameters of yeast in a deep-space environment compared to Earth ambient conditions using a 3-color LED detection system (Ricco et al. 2020; Padgen et al. 2021). We aim to expand this list to include a Spaceflight Autonomous Multigenerational Microbial Sequencer (SAMMS). SAMMS will allow for the genome level understanding of changes in growth and metabolic activity for any organism. While microbes are suitable for early studies in our proposed platform because of their small size, small and relatively less-complicated genomes, fast generation times, and relevance to life support systems; multicellular organisms can similarly be evaluated for their genetic response to the spaceflight environment. The Spaceflight Autonomous Multigenerational Microbial Sequencer (SAMMS) will enable autonomous sequencing of biological samples in plant production units, cislunar orbit and on the lunar surface to examine spaceflight effects (ie. radiation, altered gravity, reduced pressures) on plant and microbial genomes.On this team a Kennedy Space Center (KSC) space crop production and water systems microbiologist/molecular biologist works with a Johnson Space Center (JSC) International Space Station (ISS) microbial sequencing expert and an Ames Research Center (ARC) CubeSat Engineering team to convert an automated Oxford Nanopore librarypreparation and sequencing method to a fluidic CubeSat payload system. The Oxford Nanopore MinION sequencing platform has proven successful in the spaceflight environment onboard the ISS (Stahl-Rommel et al. 2021). Further long-duration spaceflight and exposure to high levels of radiation will cause genotypic effects in biological organisms that may affect their function. Monitoring the adaption of a population to the spaceflight environment and any subsequent beneficial mutations will allow for the harnessing of organisms best suited for use in life support systems. This will ensure that the selected life support-essential microorganisms maintain their intended specified function over generations of culturing in the relevant spaceflight environment without becoming hazardous to crew or spacecraft systems.

Aubrie E Orourke↗