Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “bill”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 631 records · Page 35
All sourcesNASA NTRSDOE OSTI
NASA NTRS2006

AIRS Science Accomplishments Version 4.0/Plans for Version 5

This talk is about accomplishments with AIRS data and what we have learned from almost three years of data what part of this is emerging in Version 4.0 what part we would like to see filtering into Version 5.0 and what part constitute limitations in the AIRS requirements, such as spectral and spatial resolution, which have to be deferred to the wish list for the next generation hyperspectral sounder. The AIRS calibration accuracy at the 1OOmK and stability at the 6 mK/year level are amazing. It establishes the unique capability of a cooled grating array spectrometer in Earth orbit for climate research. Data which are sufficiently clear to match the radiometric accuracy of the instrument, have a yield of less than 1%. This is OK for calibration. The 2616/cm window channel combined with the RTG.SST for tropical ocean allow excellent assessment radiometric calibration accuracy and stability. For absolute calibration verification 100mK is the limit due to cloud contamination. The 10 micron window channels can be used for stability assessment, but accuracy is limited at 300mK due to water continuum absorption uncertainties.

lessons learned↗
NASA NTRS2009

The Influence of Obliquity on Europan Cycloid Formation

Tectonic patterns on Europa are influenced by tidal stress. An important well-organized component is associated with the orbital eccentricity, which produces a diurnally varying stress as Jupiter's apparent position in Europa's sky oscillates in longitude. Cycloidal lineaments seem to have formed as cracks propagated in this diurnally varying stress field. Maps of theoretical cycloid patterns capture many of the characteristics of the observed distribution on Europa. However, a few details of the observed cycloids distribution have not reproduced by previous models. Recently, it has been shown that Europa has a finite forced obliquity, so Jupiter's apparent positon in Europa's sky will also oscillate in latitude. We explore this new type of diurnal effect on cycloid formation. We find that stress from obliquity may be the key to explaining several characteristics of observed cycloids such as the shape of equator-crossing cycloids and the shift in the crack patterns in the Argadnel Regio region. All of those improvements of the fit between observaiton and theory seem to require Jupiter crossing Europa's equatorial plane 45 deg. to 180 deg after perijove passage. Suggestive of complex orbital dynamics that lock the direction of Europe's pericenter with the direction of the ascending node at the time these cracks were formed.

Hurford, T. a.↗
NASA NTRS2008

Experiences in Bridging the Gap between Science and Decision Making at NASA's GSFC Earth Science Data and Information Services Center (GES DISC)

Recognizing the significance of NASA remote sensing Earth science data in monitoring and better understanding our planet s natural environment, NASA has implemented the Decision Support Through Earth Science Research Results program (NASA ROSES solicitations). a) This successful program has yielded several monitoring, surveillance, and decision support systems through collaborations with benefiting organizations. b) The Goddard Space Flight Center (GSFC) Earth Sciences Data and Information Services Center (GES DISC) has participated in this program on two projects (one complete, one ongoing), and has had opportune ad hoc collaborations gaining much experience in the formulation, management, development, and implementation of decision support systems utilizing NASA Earth science data. c) In addition, GES DISC s understanding of Earth science missions and resulting data and information, including data structures, data usability and interpretation, data interoperability, and information management systems, enables the GES DISC to identify challenges that come with bringing science data to decision makers. d) The purpose of this presentation is to share GES DISC decision support system project experiences in regards to system sustainability, required data quality (versus timeliness), data provider understanding of how decisions are made, and the data receivers willingness to use new types of information to make decisions, as well as other topics. In addition, defining metrics that really evaluate success will be exemplified.

Kempler, Steven↗
NASA NTRS2009

Using Geological Implications of a Physical Libration to Constrain Enceladus' Libration State

Observations of Enceladus' south pole revealed large rifts in the crust, called "tiger stripes", which exhibit higher temperatures than the surrounding terrain and are likely sources of observed eruptions. Tidal stress may periodically open the tiger stripe rifts, controlling the timing and location of eruptions. Moreover, shear motion along rifts may produce the heat to drive eruptions.

Hurford, T. A.↗
NASA NTRS2007

Overview of Key Saturn Probe Mission Trades

Ongoing studies, performed at NASA/JPL over the past two years in support of NASA's SSE Roadmap activities, proved the feasibility of a NF class Saturn probe mission. I. This proposed mission could also provide a good opportunity for international collaboration with the proposed Cosmic Vision KRONOS mission: a) With ESA contributed probes (descent modules) on a NASA lead mission; b) Early 2017 launch could be a good programmatic option for ESA-CV/NASA-NF. II. A number of mission architectures could be suitable for this mission: a) Probe Relay based architecture with short flight time (approx. 6.3-7 years); b) DTE probe telecom based architecture with long flight time (-11 years), and low probe data rate, but with the probes decoupled from the carrier, allowing for polar trajectories I orbiter. This option may need technology development for telecom; c) Orbiter would likely impact mission cost over flyby, but would provide significantly higher science return. The Saturn probes mission is expected to be identified in NASA's New Frontiers AO. Thus, further studies are recommended to refine the most suitable architecture. International collaboration is started through the KRONOS proposal work; further collaborated studies will follow once KRONOS is selected in October under ESA's Cosmic Vision Program.

probes↗
NASA NTRS2009

A Methodology for Determining Statistical Performance Compliance for Airborne Doppler Radar with Forward-Looking Turbulence Detection Capability

The objective of the research developed and presented in this document was to statistically assess turbulence hazard detection performance employing airborne pulse Doppler radar systems. The FAA certification methodology for forward looking airborne turbulence radars will require estimating the probabilities of missed and false hazard indications under operational conditions. Analytical approaches must be used due to the near impossibility of obtaining sufficient statistics experimentally. This report describes an end-to-end analytical technique for estimating these probabilities for Enhanced Turbulence (E-Turb) Radar systems under noise-limited conditions, for a variety of aircraft types, as defined in FAA TSO-C134. This technique provides for one means, but not the only means, by which an applicant can demonstrate compliance to the FAA directed ATDS Working Group performance requirements. Turbulence hazard algorithms were developed that derived predictive estimates of aircraft hazards from basic radar observables. These algorithms were designed to prevent false turbulence indications while accurately predicting areas of elevated turbulence risks to aircraft, passengers, and crew; and were successfully flight tested on a NASA B757-200 and a Delta Air Lines B737-800. Application of this defined methodology for calculating the probability of missed and false hazard indications taking into account the effect of the various algorithms used, is demonstrated for representative transport aircraft and radar performance characteristics.

Bowles, Roland L.↗
NASA NTRS2005

Team 2: AIRS Only Retrieval

This slide presentation makes the case for the retrieval of data from the Atmospheric Infrared Sounder (AIRS) Advanced Microwave Sounding Unit (AMSU). AIRS only retrieval is not only a risk reduction for failure of AMSU, but also important because NWP centers are reluctant to assimilate AMSU twice.

cloudy regression↗
NASA NTRS2008

Customer-oriented Data Formats and Services for Global Land Data Assimilation System (GLDAS) Products at the NASA GES DISC

The Global Land Data Assimilation System (GLDAS) is generating a series of land surface state (e.g., soil moisture and surface temperature) and flux (e.g., evaporation and sensible heat flux) products simulated by four land surface Models (CLM, Mosaic, Noah and VIC). These products are now accessible at the Hydrology Data and Information Services Center (HDISC), a component of NASA Goddard Earth Sciences Data and Information Services Center (GESDISC).

Fang, Hongliang↗
NASA NTRS2007

NEWS Integration: Observations

This viewgraph presentation reviews The NASA Energy and Water Cycle Study (NEWS) methodology and integration of data products from remote sensing observations. The contents include: 1) Theme Objective; 2) Scope of Current Theme-related NEWS investigation; 3) Progress; 4) Anticipated Accomplishments (near-term and long-range); 5) Assessment of Overall Science Value (to NEWS and Earth Science in general); and 6) Outstanding Issues.

remote sensing↗
NASA NTRS2007

Foundation for Heavy Lift - Early Developments in the Ares V Launch Vehicle

The Ares V Cargo Launch Vehicle (CaLV) is NASA's primary vessel for safe, reliable delivery of the Lunar Surface Access Module (LSAM) and other resources into Earth orbit, as articulated in the U.S. Vision for Space Exploration. The Ares V launch concept is shown. The foundation for this heavy-lift companion to the Ares I Crew Launch Vehicle (CLV) is taking shape within NASA and with its government and industry partners. This paper will address accomplishments in the Ares V Launch Vehicle during 2006 and 2007 and offer a preview of future activities.

McArthur, J. Craig↗
NASA NTRS2007

NTREES Testing and Operations Status

Nuclear Thermal Rockets or NTR's have been suggested as a propulsion system option for vehicles traveling to the moon or Mars. These engines are capable of providing high thrust at specific impulses at least twice that of today's best chemical engines. The performance constraints on these engines are mainly the result of temperature limitations on the fuel coupled with a limited ability to withstand chemical attack by the hot hydrogen propellant. To operate at maximum efficiency, fuel forms are desired which can withstand the extremely hot, hostile environment characteristic of NTR operation for at least several hours. The simulation of such an environment would require an experimental device which could simultaneously approximate the power, flow, and temperature conditions which a nuclear fuel element (or partial element) would encounter during NTR operation. Such a simulation would allow detailed studies of the fuel behavior and hydrogen flow characteristics under reactor like conditions to be performed. Currently, the construction of such a simulator has been completed at the Marshall Space Flight Center, and will be used in the future to evaluate a wide variety of fuel element designs and the materials of which they are fabricated. This present work addresses the operational status of the Nuclear Thermal Rocket Element Environmental Simulator or NTREES and some of the design considerations which were considered prior to and during its construction.

Emrich, Bill↗
NASA NTRS2007

Science and Measurement Requirements for a Plant Physiology and Functional Types Mission: Measuring the Composition, Function and Health of Global Land and Coastal Ocean Ecosystems

This slide presentation reviews the proposed Plant Physiology and Functional Types (PPFT) Mission. The National Academy of Sciences Decadal Survey, placed a critical priority on a Mission to observe distribution and changes in ecosystem functions. The PPFT satellite mission provides the essential measurements needed to assess drivers of change in biodiversity and ecosystem services that affect human welfare. The presentation reviews the science questions that the mission will be designed to answer, the science rationale, the science measurements, the mission concept, the planned instrumentation, the calibration method, and key signal to noise ratios and uniformity requirements.

science measurements↗
NASA NTRS2009

Design Aspects of the VLBI2010 System - Progress Report of the IVS VLBI2010 Committee

This report summarizes the progress made in developing the next generation VLBI system, dubbed the VLBI2010 system. The VLBI2010 Committee of the International VLBI Service for Geodesy and Astrometry (IVS) worked on the design aspects of the new system. The report covers Monte Carlo simulations showing the impact of the new operating modes on the final products. A section on system considerations describes the implications for the VLBI2010 system parameters by considering the new modes and system-related issues such as sensitivity, antenna slew rate, delay measurement error. RF1, frequency requirements, antenna deformation, and source structure corrections_ This is followed by a description of all major subsystems and recommendations for the network, station. and antenna. Then aspects of the feed, polarization processing. calibration, digital back end, and correlator subsystems are covered. A section is dedicated to the NASA. proof-of-concept demonstration. Finally, sections tm operational considerations, on risks and fallback options, and on the next steps complete the report.

Petrachenko, Bill↗
NASA NTRS2009

Composite Silica Aerogels Opacified with Titania

A further improvement has been made to reduce the high-temperature thermal conductivities of the aerogel-matrix composite materials described in Improved Silica Aerogel Composite Materials (NPO-44287), NASA Tech Briefs, Vol. 32, No. 9 (September 2008), page 50. Because the contribution of infrared radiation to heat transfer increases sharply with temperature, the effective high-temperature thermal conductivity of a thermal-insulation material can be reduced by opacifying the material to reduce the radiative contribution. Therefore, the essence of the present improvement is to add an opacifying constituent material (specifically, TiO2 powder) to the aerogel-matrix composites.

Paik, Jon-Ah↗
NASA NTRS2009

Multimodal Friction Ignition Tester

The multimodal friction ignition tester (MFIT) is a testbed for experiments on the thermal and mechanical effects of friction on material specimens in pressurized, oxygen-rich atmospheres. In simplest terms, a test involves recording sensory data while rubbing two specimens against each other at a controlled normal force, with either a random stroke or a sinusoidal stroke having controlled amplitude and frequency. The term multimodal in the full name of the apparatus refers to a capability for imposing any combination of widely ranging values of the atmospheric pressure, atmospheric oxygen content, stroke length, stroke frequency, and normal force. The MFIT was designed especially for studying the tendency toward heating and combustion of nonmetallic composite materials and the fretting of metals subjected to dynamic (vibrational) friction forces in the presence of liquid oxygen or pressurized gaseous oxygen test conditions approximating conditions expected to be encountered in proposed composite material oxygen tanks aboard aircraft and spacecraft in flight. The MFIT includes a stainless-steel pressure vessel capable of retaining the required test atmosphere. Mounted atop the vessel is a pneumatic cylinder containing a piston for exerting the specified normal force between the two specimens. Through a shaft seal, the piston shaft extends downward into the vessel. One of the specimens is mounted on a block, denoted the pressure block, at the lower end of the piston shaft. This specimen is pressed down against the other specimen, which is mounted in a recess in another block, denoted the slip block, that can be moved horizontally but not vertically. The slip block is driven in reciprocating horizontal motion by an electrodynamic vibration exciter outside the pressure vessel. The armature of the electrodynamic exciter is connected to the slip block via a horizontal shaft that extends into the pressure vessel via a second shaft seal. The reciprocating horizontal motion can be chosen to be random with a flat spectrum over the frequency range of 10 Hz to 1 kHz, or to be sinusoidal at any peak-to-peak amplitude up to 0.8 in. (.2 cm) and fixed or varying frequency up to 1 kHz. The temperatures of the specimen and of the vessel are measured by thermocouples. A digital video camera mounted outside the pressure vessel is aimed into the vessel through a sapphire window, with its focus fixed on the interface between the two specimens. A position transducer monitors the displacement of the pneumatic-cylinder shaft. The pressure in the vessel is also monitored. During a test, the output of the video camera, the temperatures, and the pneumatic-shaft displacement are monitored and recorded. The test is continued for a predetermined amount of time (typically, 10 minutes) or until either (1) the output of the position transducer shows a sudden change indicative of degradation of either or both specimens, (2) ignition or another significant reaction is observed, or (3) pressure in the vessel increases beyond a pre-set level that triggers an automatic shutdown.

Davis, Eddie↗
NASA NTRS2007

Machine Aided Indexing and the NASA Thesaurus

Machine Aided Indexing (MAI) is a Web-based application program for aiding the indexing of literature in the NASA Scientific and Technical Information (STI) Database. MAI was designed to be a convenient, fully interactive tool for determining the subject matter of documents and identifying keywords. The heart of MAI is a natural-language processor that accepts, as input, any user-supplied text, including abstracts, full documents, and Web pages. Within seconds, the text is analyzed and a ranked list of terms is generated. The 17,800 terms of the NASA Thesaurus serve as the foundation of the knowledge base used by MAI. The NASA Thesaurus defines a standard vocabulary, the use of which enables MAI to assist in ensuring that STI documents are uniformly and consistently accessible. Of particular interest to traditional users of the NASA Thesaurus, MAI incorporates a fully searchable thesaurus display module that affords word-search and hierarchy- navigation capabilities that make it much easier and less time-consuming to look up terms and browse, relative to lookup and browsing in older print and Portable Document Format (PDF) digital versions of the Thesaurus. In addition, because MAI is centrally hosted, the Thesaurus data are always current.

vonOfenheim, Bill↗
NASA NTRS2008

Titan Architecture Baseline Options

This slide presentation reviews the mission architecture for the Titan mission. The presentation includes information on mission architecture options, probe delivery options, and Enceladus lighting.

mission architecture↗
NASA NTRS2009

Using Satellite Data to Evaluate Linkages Between Land Cover/Land Use and Hypertension in a National Cohort

Coincident with global expansion of urban areas has been an increase in hypertension. It is unclear how much the urban environment contributes as a risk factor for blood pressure differences, and how much is due to a variety of environmental, lifestyle, and demographic correlates of urbanization. Objectives/Purpose: The purpose of this study is to examine the relationship between living environment (defined as urban, suburban, or rural) and hypertension in selected regions from the REasons for Geographic And Racial Differences in Stroke (REGARDS) cohort. Methods: REGARDS is a national cohort of 30,228 participants from the 48 contiguous United States. We used data from 4 metropolitan regions (Philadelphia, Atlanta, Minneapolis and Chicago) for this study (n=3928). We used Land Cover/Land Use (LCLU) information from the 30-meter National Land Cover Data. Results: Overall, 1996 (61%) of the participants were hypertensive. We characterized participants into urban, suburban or rural living environments using the LCLU data. In univariate models, we found that living environment is associated with hypertension, but that after adjustment for known hypertension risk factors, the relationship was no longer present at the 95% confidence level. Conclusions: LCLU data can be utilized to characterize the living environment, which in turn can be applied to studies of public health outcomes. Further study regarding the relationship between hypertension and living environment should focus on additional characteristics of the associated environment.

McClure, Leslie↗