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At least 883 records · Page 49

Cathodoluminescence observations of in situ aqueous destruction of chondrules in the Murchison CM chondrite

A low-power cathodoluminescence (CL) mosaic of a 1x2 cm section of the Murchison CM chondrite contains chondrules of two types: one contains olivines with red CL and is thought to be the equivalent of group A chondrules of Sears et.; and one without observable CL, which is probably equivalent to their group B chondrules. Both types of chondrule contain dust mantles with a characteristic uniform red CL due to very fine-grained forsterites, but the mantles of group A chondrules have a complex internal structure and are much thicker than the relatively thin rims on the group B chondrules. The variety of internal textures and the progressive integration of the objects with the surrounding matrix suggests to us that these features are large group A chondrules in the process of being destroyed by aqueous alteration. Prior to aqueous alteration, group A chondrules in CM chondrites were larger than group B chondrules, which is contrary to the situation in ordinary chondrites and were apparently destroyed more rapidly than group B chondrules by aqueous alteration.

Sears, Derek W. G.↗

CCD data acquisition systems at Lick and Keck Observatories

This paper will describe and compare two distinct but related CCD data acquisition systems (DAS) currently under development at Lick and Keck Observatories. Although these two systems have a number of major architectural differences, they share a considerable amount of common hardware and software. Both of these new systems build on a large body of proven software that is the foundation of the existing CCD DAS currently in use at Lick Observatory. Both will provide support for reading up to four on-chip amplifiers per CCD and/or reading out mosaics of CCD chips. In addition, they will provide the capability for interactive, real-time adjustment of CCD waveforms for engineering purposes. Each of these two systems is composed of three major subsystems: (1) an instrument computer and its software; (2) a data capture computer and its software; and (3) a CCD/dewar controller and its software. The instrument computer is a Unix workstation, and the functions it provides include user interfaces, the interactive real-time display of CCD images, and the recording of image and FITS header data to disk and/or tape. The data capture computer is responsible for the packaging and high-speed transfer of the CCD pixel data stream into a bulk RAM, and the subsequent transfer of this data to the instrument computer. The CCD/dewar controller generates the waveforms for clocking the CCD, digitizes the pixel data, and transmits it via high-speed link to the data capture computer. It is also responsible for monitoring and controlling the dewar temperature and cryogen levels. Given the number of different types of processors and high-speed data links employed in both systems, a major emphasis of this paper will be on the various forms of interprocessor communications utilized for data transfer and distributed process synchronization.

Kibrick, R. I.↗

The IDL astronomy user's library

IDL (Interactive Data Language) is a commercial programming, plotting, and image display language, which is widely used in astronomy. The IDL Astronomy User's Library is a central repository of over 400 astronomy-related IDL procedures accessible via anonymous FTP. The author will overview the use of IDL within the astronomical community and discuss recent enhancements at the IDL astronomy library. These enhancements include a fairly complete I/O package for FITS images and tables, an image deconvolution package and an image mosaic package, and access to IDL Open Windows/Motif widgets interface. The IDL Astronomy Library is funded by NASA through the Astrophysics Software and Research Aids Program.

Landsman, W. B.↗

UIT support observations archive

We are in the process of archiving the approximately 1.2Tbytes of imaging data acquired in support of UIT observations. The UIT is one of three telescopes comprising the ASTRO spacecraft and is a 38-cm f/9 Ritchey-Chretien telescope with wavelength coverage 1200 A to 3000 A and a 40 arcminute diameter field-of-view at 4 min FWHM resolution. During the ASTRO shuttle mission, there were 65 different pointings (some with multiple targets) of the UIT and hence 65 fields. Our support data of these fields were obtained with the KPNO and CTIO 0.9m telescopes and several of the 2048x2048 CCD's. Our images are typically about 20 acrminutes on a side and contain the entire UV target except for nearby galaxies, for which mosaiced images were created. All good quality images in the broadband and narrow band filters for every target are being archived. Though all of the UIT targets were well studied astronomical objects, these frames are many of the first large field format images of them and, when combined with the soon to be released UV frames, provide a unique dataset. These data were already used to address a wide variety of astronomical questions. Vacuum ultraviolet (VUV) observations were used to study star formation in a sample of nearby galaxies, since integrated VUV - optical colors provide the most sensitive available measure of the formation rate of massive stars. The blue stages later in stellar evolution are also being studied. These data allow more accurate determination of the helium and metallicities of hothorzontal branch stars. These data are being prepared to release to the public in CD-ROM format through the National Space Science Data Center.

Smith, Eric P.↗

A Collection of The Movies

This video contains computer-generated animation made from still data sets processed by computer to give the illusion of flying around the objects. 'Earth - The Movie' uses cloud data from satellites and geographical data from maps. 'L.A. - The Movie' was taken from Landsat data of the Los Angeles area. This was the first experimental demonstration of the technology. 'Mars - The Movie' was taken from Viking orbiter data. 'Miranda - The Movie' was made from a mosaic of 9 frames taken by Voyager of the Uranium moon, Miranda. The last movie is 'Monterey - The Bay.'

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First Galileo image of asteroid 243 Ida

The second spacecraft encounter with an asteroid has yielded an unprecedentedly high resolution portrait of 243 Ida. On 28 Aug. 1993, Galileo obtained an extensive data set on this small member of the Koronis family. Most of the data recorded on the tape recorder will be returned to Earth in spring 1994. A five-frame mosaic of Ida was acquired with good illumination geometry a few minutes before closest approach; it has a resolution of 31 to 38 m/pixel amd was played back during Sept. 1993. Preliminary analyses of this single view of Ida are summarized.

Chapman, C. R.↗

NASA Access Mechanism: Lessons learned document

The six-month beta test of the NASA Access Mechanism (NAM) prototype was completed on June 30, 1993. This report documents the lessons learned from the use of this Graphical User Interface to NASA databases such as the NASA STI Database, outside databases, Internet resources, and peers in the NASA R&D community. Design decisions, such as the use of XWindows software, a client-server distributed architecture, and use of the NASA Science Internet, are explained. Users' reactions to the interface and suggestions for design changes are reported, as are the changes made by the software developers based on new technology for information discovery and retrieval. The lessons learned section also reports reactions from the public, both at demonstrations and in response to articles in the trade press and journals. Recommendations are included for future versions, such as a World Wide Web (WWW) and Mosaic based interface to heterogeneous databases, and NAM-Lite, a version which allows customization to include utilities provided locally at NASA Centers.

Burdick, Lisa↗

Mars Pathfinder: Landing Site Computer Animation [and] Rocky IV

This video uses computer graphic models of the heat shield, lander, and parachute to present an artist's concept of the Mars Pathfinder descent. Viking image mosaics are used to create a rotating globe of Mars. A separate segment presents a simulated flight over the Mars Pathfinder landing site. The second part of the film describes the development of Rocky IV, the latest in a series of planetary rovers developed in preparation for the Mars Pathfinder mission.

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Asteroseismology with FRESIP: A meter class space telescope

The requirements for asteroseismology and searching for occulting inner planets are similar. The FRESIP mission will be suited to making asteroseismology measurements. Recommendation: Use 30-60 second integrations from one or more CCD's in the FRESIP mosaic, sampled continuously for the entire mission to measure stellar non-radial oscillations with amplitudes of parts per million and frequencies of 0.1 to 10 MHz. These measurements lead to determination of stellar interior helium abundances, rotation rates, depth of convection zones and measuring stellar cycle frequency changes for a variety of stellar types, enabling major advances in stellar structure and evolutionary theories.

Milford, Peter↗

The Role of Computers in Research and Development at Langley Research Center

This document is a compilation of presentations given at a workshop on the role cf computers in research and development at the Langley Research Center. The objectives of the workshop were to inform the Langley Research Center community of the current software systems and software practices in use at Langley. The workshop was organized in 10 sessions: Software Engineering; Software Engineering Standards, methods, and CASE tools; Solutions of Equations; Automatic Differentiation; Mosaic and the World Wide Web; Graphics and Image Processing; System Design Integration; CAE Tools; Languages; and Advanced Topics.

Wieseman, Carol D.↗

Automating testbed documentation and database access using World Wide Web (WWW) tools

A method for providing uniform transparent access to disparate distributed information systems was demonstrated. A prototype testing interface was developed to access documentation and information using publicly available hypermedia tools. The prototype gives testers a uniform, platform-independent user interface to on-line documentation, user manuals, and mission-specific test and operations data. Mosaic was the common user interface, and HTML (Hypertext Markup Language) provided hypertext capability.

Ames, Charles↗

A hypertext-based Internet-assessable database for the MSFC Technology Transfer Office

There exists a continuing need to disseminate technical information and facilities capabilities from NASA field centers in an effort to promote the successful transfer of technologies developed with public funds to the private sector. As technology transfer is a stated NASA mission, there exists a critical need for NASA centers to document technology capabilities and disseminate this information on as wide a basis as possible. Certainly local and regional dissemination is critical, but global dissemination of scientific and engineering facilities and capabilities gives NASA centers the ability to contribute to technology transfer on a much broader scale. Additionally, information should be disseminated in a complete and rapidly available form. To accomplish this information dissemination, the unique capabilities of the Internet are being exploited. The Internet allows widescale information distribution in a rapid fashion to aid in the accomplishment of technology transfer goals established by the NASA/MSFC Technology Transfer Office. Rapid information retrieval coupled with appropriate electronic feedback, allows the scientific and technical capabilities of Marshall Space Flight Center, often unique in the world, to be explored by a large number of potential benefactors of NASA (or NASA-derived) technologies. Electronic feedback, coupled with personal contact with the MSFC Technology Transfer Office personnel, allows rapid responses to technical requests from industry and academic personnel as well as private citizens. The remainder of this report gives a brief overview of the Mosaic software and a discussion of technology transfer office and laboratory facilities data that have been made available on the Internet to promote technology transfer.

Jackson, Jeff↗

Design and implementation of two two-week Teacher Enhancement Institutes

During this summer, I have been part of a four team effort that planned and executed two two-week Teacher Enhancement Institutes (TEI) for 40 K-8 teachers from this area. The TEI was designed to enhance teachers' background in aeronautics and technology so that they would be better equipped to encourage and to train students in the mathematics, science, and technology fields. The teachers were given a stipend and three graduate credits from Christopher Newport University for their participation in this program. The four ASEE fellows worked together to develop objectives and a schedule of activities for each two-week session based on the program outline given in the grants that were funding this effort. We divided the responsibilities in coordinating and implementing each part of the TEI based on the specific strengths and background of each ASEE fellow. My specific responsibilities were: (1) to develop the course syllabus and generally handle all matters involved with the graduate course; (2) coordinate the follow-up sessions; and (3) design and manage half of the technology sessions that we had scheduled (approximately 30% of the TEI was devoted to technology). Because the first two responsibilities were primarily administrative in nature, I will address only the last. The technology sessions were divided into computer-only and other technologies (e.g., television and digital technology including scanning, digital photography and CD-ROM). I had responsibility for the computer-only technology sessions. The emphasis of these sessions was on use of the Internet specifically to locate and use educational resources. To maximize learning, these sessions were hands-on with two teachers at each computer. Each teacher received instruction in, and actually used, the most popular tools available on the Internet: email (they were given temporary accounts at NASA LaRC), anonymous ftp and archie, gopher and veronica, mosaic, and telnet. Teachers participated in hands-on workshops to learn about these programs, but were also given time during the two-week session to explore on their own and to find resources on the Net that specifically met their needs. In order to ensure that Internet access continues after their return to the classroom, aIl teachers who did not have them also applied for Learning Link accounts (from WHRO, the local public television station) and Virginia Pen accounts (from the Department of Education of Virginia), both of which allow textbased access to Internet. In addition to getting exposure to and practice with Internet tools, teachers were aIso given a hands-on seminar (and also given practice time) on ClarisWorks, an integrated word processing, spreadsheet, database, and paint package. The technology sessions (and TEI as a whole) were enthusiastically received by both new and more experienced teachers as extremely helpful in improving their ability to use technology in developing lesson pIans.

Lambert, Lynn↗

Teacher Enhancement Institute

In a team building, team teaching strategy with four faculty, can learning strategies such as educational technology and problem based learning be provided to forty local teachers of primary, elementary, and secondary students? The impetus for the effort is to provide information about science and engineering at NASA and motivate students to pursue careers in science and technology. Teachers, identified and selected through a rigorous application procedure, participated in a two week workshop for a graduate credit. Teachers were exposed to computer applications such as INTERNET, MOSAIC, Power Machintosh word processing, NASA scientists, and laboratory experiments. Teachers were evaluated on level and quality of their participation, design of teacher application materials and relevant lesson plans and presentations. The results show that teachers, regardless of preparation and background, can learn science and engineering applications and develop relevant materials to transfer information to their classroom. Follow-up during the academic year will show that teachers are successfully using materials.

Simmons, Ron W.↗

Mapping of the Ronda peridotite massif (Spain) from AVIRIS spectro-imaging survey: A first attempt

In both AVIRIS and ISM data, through the use of mixing models, geological boundaries of the Ronda massif are identified with respect to the surrounding rocks. We can also yield first-order vegetation maps. ISM and AVIRIS instruments give consistent results. On the basis of endmember fraction images, it is then possible to discard areas highly vegetated or not belonging to the peridotite massif. Within the remaining part of the mosaic, spectro-mixing analysis reveals spectral variations in the peridotite massif between the well-exposed areas. Spatially organized units are depicted, related to differences in the relative depth of the absorption band at 1 micron, and it may be due to a different pyroxene content. At this stage, it is worth noting that, although mineralogical variations observed in the rocks are at a sub-pixel scale for the airborne analysis, we see an emerging spatial pattern in the distribution of spectral variations across the massif which might be prevailingly related to mineralogy. Although it is known from fieldwork that the Ronda peridotite massif exhibits mineralogical variations at local scale in the content of pyroxene, and at regional scale in different mineral facies, ranging from garnet-, to spinel- to plagioclase-lherzolites, no attempt has been done yet to produce a synoptic map relating the two scales of analysis. The present work is a first attempt to reach this objective, though a lot more work is still required. In particular, for the purpose of mineralogical interpretation, it is critical to relate the airborne observation to field work and laboratory spectra of Ronda rocks already obtained, with the use of image endmembers and associated reference endmembers. Also, the pretty rough linear mixing model used here is taken as a 'black-box' process which does not necessarily apply correctly to the physical situation at the sub-pixel level. One may think of using the ground-truth observations bearing on the sub-pixel statistical characteristics (texture, structural pattern, surface distribution and vegetation contribution (grass,..)) to produce a more advanced mixing model, physically appropriate to the geologic and environmental contexts.

Pinet, P. C.↗

Searching the SOHO online catalogs

The SOHO on-line catalogs will contain information about the observations from several made or planned campaigns, that must be available to scientists who wish to use SOHO data. The World Wide Web (WWW) was chosen as the interface to the SOHO on-line catalogs, because it is easy to use, well suited to a geographically distributed user community, and freely available. Through the use of a forms-capable WWW client such as Mosaic or Lynx, a scientist will be able to browse through the catalogs of observations in a very simple, self explanatory way. Data files can then be selected from the returned lists for either immediate transferring or sending on tape by mail, with appropriate checks for whether data is in the public domain or not.

Thompson, William↗

Use of TOPSAR digital elevation data to determine the 3-dimensional shape of an alluvial fan

Landforms in arid regions record the interplay between tectonic forces and climate. Alluvial fans are a common landform in desert regions where the rate of uplift is greater than weathering or sedimentation. Changes in uplift rate or climatic conditions can lead to isolation of the currently forming fan surface through entrenchment and construction of another fan either further from the mountain front (decreased uplift or increased runoff) or closer to the mountain front (increased uplift or decreased runoff). Thus, many alluvial fans are made up of a mosaic of fan units of different age, some older than 1 million years. For this reason, determination of the stages of fan evolution can lead to a history of uplift and runoff. In an attempt to separate the effects of tectonic (uplift) and climatic (weathering, runoff, sedimentation) processes on the shapes of alluvial fan units, a modified conic equation developed by Troeh (1965) was fitted to TOPSAR digital topographic data for the Trail Canyon alluvial fan in Death Valley, California. This allows parameters for the apex position, slope, and radial curvature to be compared with unit age.

Farr, Tom G.↗

Regional mapping of forest canopy water content and biomass using AIRSAR images over BOREAS study area

In recent years, monitoring vegetation biomass over various climate zones has become the primary focus of several studies interested in assessing the role of the ecosystem responses to climate change and human activities. Airborne and spaceborne Synthetic Aperture Radar (SAR) systems provide a useful tool to directly estimate biomass due to its sensitivity to structural and moisture characteristics of vegetation canopies. Even though the sensitivity of SAR data to total aboveground biomass has been successfully demonstrated in many controlled experiments over boreal forests and forest plantations, so far, no biomass estimation algorithm has been developed. This is mainly due to the fact that the SAR data, even at lowest frequency (P-band) saturates at biomass levels of about 200 tons/ha, and the structure and moisture information in the SAR signal forces the estimation algorithm to be forest type dependent. In this paper, we discuss the development of a hybrid forest biomass algorithm which uses a SAR derived land cover map in conjunction with a forest backscatter model and an inversion algorithm to estimate forest canopy water content. It is shown that unlike the direct biomass estimation from SAR data, the estimation of water content does not depend on the seasonal and/or environmental conditions. The total aboveground biomass can then be derived from canopy water content for each type of forest by incorporating other ecological information. Preliminary results from this technique over several boreal forest stands indicate that (1) the forest biomass can be estimated with reasonable accuracy, and (2) the saturation level of the SAR signal can be enhanced by separating the crown and trunk biomass in the inversion algorithm. We have used the JPL AIRSAR data over BOREAS southern study area to test the algorithm and to generate regional scale water content and biomass maps. The results are compared with ground data and the sources of errors are discussed. Several SAR images in synoptic modes are used to generate the parameter maps. The maps are then combined to generate mosaic maps over the BOREAS modeling grid.

Saatchi, Sasan↗