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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 145 records · Page 8
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NASA NTRS1995

Comprehension and retrieval of failure cases in airborne observatories

This paper describes research dealing with the computational problem of analyzing and repairing failures of electronic and mechanical systems of telescopes in NASA's airborne observatories, such as KAO (Kuiper Airborne Observatory) and SOFIA (Stratospheric Observatory for Infrared Astronomy). The research has resulted in the development of an experimental system that acquires knowledge of failure analysis from input text, and answers questions regarding failure detection and correction. The system's design builds upon previous work on text comprehension and question answering, including: knowledge representation for conceptual analysis of failure descriptions, strategies for mapping natural language into conceptual representations, case-based reasoning strategies for memory organization and indexing, and strategies for memory search and retrieval. These techniques have been combined into a model that accounts for: (a) how to build a knowledge base of system failures and repair procedures from descriptions that appear in telescope-operators' logbooks and FMEA (failure modes and effects analysis) manuals; and (b) how to use that knowledge base to search and retrieve answers to questions about causes and effects of failures, as well as diagnosis and repair procedures. This model has been implemented in FANSYS (Failure ANalysis SYStem), a prototype text comprehension and question answering program for failure analysis.

Alvarado, Sergio J.↗
NASA NTRS1996

Data Report of Hydrographic Observations: Geomagnetic Observations at the Hatizyo Hydrographic Observatory for the Year 1994

The Hatizyo Hydrographic Observatory, which is one of the essential magnetic observatories in Japan, was established in 1979 and is currently operated by the Hydrographic Department, Maritime Safety Agency. This is the annual report compiled from the results of magnetic observations carried out at the observatory in 1994. As to the instruments used for magnetic observations, the digital recording variometer was replaced by a fluxgate magnetometer in 1986, and one set each of the proton and fluxgate magnetometers was additionally installed in January and October 1992, respectively.

Source record↗
NASA NTRS1995

Data Report of Hydrographic Observations: Geomagnetic Observations at the Hatizyo Hydrographic Observatory for the Year 1993

The Hatizyo Hydrographic Observatory, which is one of the essential magnetic observatories in Japan, was established in 1979 and is currently operated by the Hydrographic Department, Maritime Safety Agency. This is the annual report compiled from the results of magnetic observations carried out at the observatory in 1993. As to the instruments used for magnetic observations, the digital recording variometer was replaced by a fluxgate magnetometer in 1986, and one set each of the proton and fluxgate magnetometers was additionally installed in January and October 1992, respectively.

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NASA NTRS1998

Construction and Operation of 1-5 Micron Array Camera (Minne-Cam) for the University of Minnesota Observatories

The 1-5 Micron Imaging Infrared (IR) Camera (MinneCam) for the University of Minnesota (UM) observatories has been constructed. It is presently housed at the Mt. Lemmon Observing Facility (MLOF) in Arizona for its inaugural observing run. MinneCam is testing and comparing various observational approaches, and will produce data sets that can be used to define and test data analysis algorithms. The camera is being used in support of studies to define strategies for using NASA's Space Infrared Telescope Facility (SIRTF) for observations of comets and other targets of opportunity. A long term goal is to modify the instrument to accommodate imaging polarimetry. This instrument is presently putting the University of Minnesota observatories in competition with other major IR observatories and is allowing us to develop state-of-the-art instrumentation for the U of M's proposed 2.4 meter telescope proposed jointly with NOAO and the University of Colorado. The camera has provided important research opportunities for the Minnesota IR group, including other faculty and graduate students in the Department of Astronomy.

Gehrz, Robert D.↗
NASA NTRS1999

Shuttle and Transfer Orbit Thermal Analysis and Testing of the Chandra X-Ray Observatory Charge-Couple Device Imaging Spectrometer Radiator Shades

Thermal analyses of the Shuttle and Transfer Orbit of the Advanced X-Ray Astrophysics Facility Charge-Coupled Device (CCD) Imaging Spectrometer (ACIS), one of two science instruments on the Chandra X-Ray Observatory, revealed a low-earth orbit (LEO) overheating problem on the goldized Kapton faces of two radiator shades. The shades were coated with the goldized Kapton to provide a low hemispherical emittance to minimize direct and backloaded heating from the sun and the observatory and high specularity to optimize the coupling to space on two passive radiators which cool the focal plane to -120 C +/- 1 C during on-orbit operations. Since the observatory has a highly elliptical final orbit of 10,000 kilometers by 140,000 kilometers and the ACIS radiators and shades are oriented anti-sun, the high solar absorptance to emittance ratio of the goldized Kapton was not an issue. However, during Shuttle bay-to-earth operations, the short duration solar heating occurring near the eclipse entry and exit resulted in shade temperatures in excess of the cure temperature of the adhesive used to bond the goldized Kapton and honeycomb face-sheets. The detailed thermal analysis demonstrating the LEO overheating as well as the redesign options and thermal testing of a redesigned development unit shade are presented.

Sharp, John R.↗
NASA NTRS2000

Considerations for a Next Generation GRB Observatory

A framework will be described for the planning of a Next Generation Burst Observatory. This Observatory, using Swift as a pathfinder mission, would study early star formation and early galaxy formation at very high redshifts through observations of thousands of GRBS, their afterglows and environments. It is suggested that the international GRB community should begin some initial studies for such an observatory.

Fishman, Gerald J.↗
NASA NTRS2000

Considerations for a Next Generation GRB Observatory

A framework will be described for the planning of a Next Generation Burst Observatory. This Observatory, using Swift as a pathfinder mission, would study early star formation and early galaxy formation at very high redshifts through observations of thousands of GRBs, their afterglows and environments. It is suggested that the international GRB community should begin some initial studies for such an observatory.

Fishman, Gerald J.↗
NASA NTRS2001

Code Sharing and Collaboration: Experiences from the Scientist's Expert Assistant Project and their Relevance to the Virtual Observatory

In the Virtual Observatory (VO), software tools will perform the functions that have traditionally been performed by physical observatories and their instruments. These tools will not be adjuncts to VO functionality but will make up the very core of the VO. Consequently, the tradition of observatory and system independent tools serving a small user base is not valid for the VO. For the VO to succeed, we must improve software collaboration and code sharing between projects and groups. A significant goal of the Scientist's Expert Assistant (SEA) project has been promoting effective collaboration and code sharing between groups. During the past three years, the SEA project has been developing prototypes for new observation planning software tools and strategies. Initially funded by the Next Generation Space Telescope, parts of the SEA code have since been adopted by the Space Telescope Science Institute. SEA has also supplied code for SOFIA, the SIRTF planning tools, and the JSky Open Source Java library. The potential benefits of sharing code are clear. The recipient gains functionality for considerably less cost. The provider gains additional developers working with their code. If enough users groups adopt a set of common code and tools, defacto standards can emerge (as demonstrated by the success of the FITS standard). Code sharing also raises a number of challenges related to the management of the code. In this talk, we will review our experiences with SEA - both successes and failures - and offer some lessons learned that may promote further successes in collaboration and re-use.

Jones, Jeremy↗
NASA NTRS2001

Observations of GRBs: Current Research and Planning for a Next Generation GRB Observatory

The basic observed properties of GRBs in the hard x-ray and gamma-ray region will be reviewed, primarily using analyses from BATSE data. Summaries of new BATSE observations that are presented in this symposium and other work in progress are given. Finally, a framework will be described-for the planning of a Next Generation Burst Observatory. This Observatory, using Swift as a pathfinder mission, would study early star formation and early galaxy formation at very high redshifts through observations of thousands of GRBs, their afterglows and environments. It is suggested that the international GRB community should begin some initial studies for such an observatory.

Fishman, Gerald J.↗
NASA NTRS2001

Code Sharing and Collaboration: Experiences From the Scientist's Expert Assistant Project and Their Relevance to the Virtual Observatory

In the Virtual Observatory (VO), software tools will perform the functions that have traditionally been performed by physical observatories and their instruments. These tools will not be adjuncts to VO functionality but will make up the very core of the VO. Consequently, the tradition of observatory and system independent tools serving a small user base is not valid for the VO. For the VO to succeed, we must improve software collaboration and code sharing between projects and groups. A significant goal of the Scientist's Expert Assistant (SEA) project has been promoting effective collaboration and code sharing among groups. During the past three years, the SEA project has been developing prototypes for new observation planning software tools and strategies. Initially funded by the Next Generation Space Telescope, parts of the SEA code have since been adopted by the Space Telescope Science Institute. SEA has also supplied code for the SIRTF (Space Infrared Telescope Facility) planning tools, and the JSky Open Source Java library. The potential benefits of sharing code are clear. The recipient gains functionality for considerably less cost. The provider gains additional developers working with their code. If enough users groups adopt a set of common code and tools, de facto standards can emerge (as demonstrated by the success of the FITS standard). Code sharing also raises a number of challenges related to the management of the code. In this talk, we will review our experiences with SEA--both successes and failures, and offer some lessons learned that might promote further successes in collaboration and re-use.

Korathkar, Anuradha↗
NASA NTRS1994

The Next Generation Airborne Observatory: SOFIA

NASA, DARA, and the astronomical community have planned SOFIA (Stratospheric Observatory for Infrared Astronomy) to extend and expand the capabilities of airborne astronomy. Just as the Kuiper Airborne Observatory telescope has three times the aperture of its Learjet predecessor, SOFIA's aperture (2.5 m) will be three times that of the KAO. Thus SOFIA will surpass the angular resolution of the KAO by a factor of three and its per-pixel sensitivity by a factor approximately 10 at wavelengths beyond 10 micrometers. Following the tradition of the KAO and Learjet programs, the user community will provide most of the SOFIA focal plane instruments. Scientists will fly their new instruments as soon as they become operational, assuring immediate application of state-of-the-art technology throughout the anticipated 20 year observatory lifetime. Annual peer review of submitted proposals guarantees a vigorous observing program. Armed by 15-20 different instrument teams, reinforced by an additional approximately 50 guest investigator groups, and flying 160 8-hour sorties per year, SOFIA will be used to attack a very broad range of astronomical problems. To name just a few, observations made from SOFIA will: greatly extend our understanding of the star-formation process, including collapse, accretion, and outflow phenomena; penetrate the obscuring dust of the Milky way to reveal gas motions, the luminosity distribution, and possibly the powerful excitation mechanism at the center of our Galaxy; and probe km-scale structure of planetary atmospheres and ring systems. The Astronomy and Astrophysics Survey (Bahcall) committee ranked SOFIA as the highest priority moderate cost new mission for NASA in the 1990s. SOFIA has been thoroughly studied and is ready to start development. If funding is available in 1996 as currently planned by NASA and DARA Astrophysics Offices, SOFIA could be flying by the end of the decade.

Erickson, E. F.↗
NASA NTRS2002

On Overview of the Performance and Scientific Results from the Chandra X-Ray Observatory

The Chandra X-Ray Observatory (CXO) was launched on 1999 July 23 by the Columbia Space Shuttle. The first X-rays focused by the telescope were seen on 1999 August 12 after the satellite systems were activated. Beginning with the first observation, it was clear that the telescope was not damaged by the launch environment and was operating as planned. After the early surprise due to the discovery that the telescope concentrated CCD-damaging low-energy protons far more efficiently than had been expected, the observatory is performing optimally and is returning excellent scientific data. Together with other space observatories, especially XMM-Newton, it is obvious that we have entered a new era of discovery in high-energy astrophysics.

Weisskopf, M. C.↗
NASA NTRS2003

Heterodyne Receiver Requirements for the Single Aperture Far-Infrared (SAFIR) Observatory

In the next few years, work will commence in earnest on the development of technology for the next generation large cryogenic far-infrared telescope: the Single Aperture Far- Infrared (SAFIR) Observatory. SAFIR's science goals are driven by the fact that youngest stages of almost all phenomena in the universe are shrouded in absorption by cool dust, resulting in the energy being emitted primarily in the far-infrared. The earliest stages of star formation, when gas and dust clouds are collapsing and planets forming, can only be observed in the far-infrared. Spectral diagnostics in the far-infrared are typically quite narrow (approx. 1 km/s) and require high sensitivity to detect them. SAFIR is a 10 m-class telescope designed for cryogenic operation at L2, removing all sources of thermal emission from the telescope and atmosphere. Despite its limited collecting area and angular resolution as compared to the ALMA interferometer, its potential for covering the entire far-infrared band cannot be matched by any ground-based or airborne observatory. This places a new challenge on heterodyne receivers: broad frequency coverage. The ideal mixer would be able to detect frequencies over several octaves (e.g., 0.6 THz - 12 THz) with near quantum-limited performance at all frequencies. In contrast to ground-based observatories, it may not be necessary to strive for high instantaneous bandwidth, as direct detection spectroscopy is preferable for bandwidths of Delta v/ v greater than or equal to 10(exp -4) (e.g., 1 GHz at 10 THz). We consider likely directions for technology development for heterodyne receivers for SAFIR.

Benford, Dominic J.↗
NASA NTRS2001

Testing and Calibration of the NASA COR1 Coronagraph for the Solar Terrestrial Relations Observatory (STEREO)

This proposal is for a no cost extension on the period of performance of the existing grant. The period of performance shall be extended to the end of FY 2003. This extension is required due to schedule changes in the COR1 program. Funding for Phase II and Phase III of this grant has been obtained. This unsolicited proposal was for scientific and engineering collaboration between NASA s Goddard Space Flight Center (GSFC) and HAO. Performance testing of the COR1 engineering test unit has been partially completed. The COR1 coronagraph engineering test unit requires further testing at NASA s GSFC and the National Center for Atmospheric Research (NCAR) Mauna Loa Solar Observatory (MLSO), operated by the High Altitude Observatory (HAO). HAO personnel have recently supported efforts to test component and breadboard versions of the COR1 using the NCAR Vacuum Tunnel Facility (NVTF). HAO personnel will continue to work closely with scientists and engineers at NASA/GSFC in the development, design, assembly, testing, and operation of this key element of NASA's Solar Terrestrial Relations Observatory (STEREO) mission. The element is an internally-occulted coronagraphic telescope, and the design and development effort is already underway at GSFC.

Burkepile, J. T.↗
NASA NTRS2004

The Generation-X X-ray Observatory Vision Mission and Technology Study

The new frontier in astrophysics is the study of the birth and evolution of the first stars, galaxies and black holes in the early Universe. X-ray astronomy opens a window into these objects by studying the emission from black holes, supernova explosions and the gamma-ray burst afterglows of massive stars. However, such objects are beyond the grasp of current or near-future observatories. X-ray imaging and spectroscopy of such distant objects will require an X-ray telescope with large collecting area and high angular resolution. Our team has conceived the Generation-X Vision Mission based on an X-ray observatory with 100 sq m collecting area at 1 keV (1000 times larger than Chandra) and 0.1 arcsecond angular resolution (several times better than Chandra and 50 times better than the Constellation-X resolution goal). Such an observatory would be capable of detecting the earliest black holes and galaxies in the Universe, and will also study extremes of density, gravity, magnetic fields, and kinetic energy which cannot be created in laboratories. NASA has selected the Generation-X mission for study under its Vision Mission Program. We describe the studies being performed to develop the mission concept and define candidate technologies and performance requirements for Generation-X. The baseline Generation-X mission involves four 8m diameter X-ray telescopes operating at Sun-Earth L2. We trade against an alternate concept of a single 26m diameter telescope with focal plane instruments on a separate spacecraft. A telescope of this size will require either robotic or human-assisted in-flight assembly. The required effective area implies that extremely lightweight grazing incidence X-ray optics must be developed. To achieve the required aerial density of at least 100 times lower than in Chandra, we will study 0.1mm thick mirrors which have active on-orbit figure control. We discuss the suite of required detectors, including a large FOV high angular resolution imager, a cryogenic imaging spectrometer and a grating spectrometer. We outline the development roadmap to confront the many technological challenges far implementing the Generation-X mission.

Figueroa-Feliciano, Enectali↗
NASA NTRS2005

Five Years of Observations with the Chandra X-Ray Observatory

The Chandra X-ray Observatory is the X-ray component of NASA's Great Observatory Program. The Chandra X-Ray Observatory has now been operating successfully for over five years. We present here brief overview of the technical performance and some of the remarkable discoveries that have been made.

Weisskopf, M. C.↗
NASA NTRS2005

The Virtual Solar Observatory: Still a Small Box

Two and a half years after a design study began, and a year and a half after development commenced, version 1.0 of the Virtual Solar Observatory (VSO) was released at the 2004 Fall AGU meeting. Although internal elements of the VSO have changed, the basic design has remained the same, reflecting the team's belief in the importance of a simple, robust mechanism for registering data provider holdings, initiating queries at the appropriate provider sites, aggregating the responses, allowing the user to iterate before making a final selection, and enabling the delivery of data directly from the providers. In order to make the VSO transparent, lightweight, and portable, the developers employed XML for the registry, SOAP for communication between a VSO instance and data services, and HTML for the graphic user interface (GUI's). We discuss the internal data model, the API, and user responses to various trial GUI's as typical design issues for any virtual observatory. We also discuss the role of the "small box" of data search, identification, and delivery services provided by the VSO in the larger, Sun-Solar System Connection virtual observatory (VxO) scheme.

Gurman, J. B.↗