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Additions to the NASA Aeronautics and Space Database as of 09/30/2009
20090032801 NASA Johnson Space Center, Houston, TX, United States
Sea-Level Flight Demonstration and Altitude Characterization of a LO2/LCH4 Based Accent Propulsion Lander
Collins, Jacob; Hurlbert, Eric; Romig, Kris; Melcher, John; Hobson, Aaron; Eaton, Phil; [2009]; In English; 45th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 2 - 5 Aug. 2009, Denver, CO, United States; Original contains color and black and white illustrations
Report No.(s): JSC-CN-18506; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090032801
A 1,500 lbf thrust-class liquid oxygen (LO2)/Liquid Methane (LCH4) rocket engine was developed and tested at both sea-level and simulated altitude conditions. The engine was fabricated by Armadillo Aerospace (AA) in collaboration with NASA Johnson Space Center. Sea level testing was conducted at Armadillo Aerospace facilities at Caddo Mills, TX. Sea-level tests were conducted using both a static horizontal test bed and a vertical take-off and landing (VTOL) test bed capable of lift-off and hover-flight in low atmosphere conditions. The vertical test bed configuration is capable of throttling the engine valves to enable liftoff and hover-flight. Simulated altitude vacuum testing was conducted at NASA Johnson Space Center White Sands Test Facility (WSTF), which is capable of providing altitude simulation greater than 120,000 ft equivalent. The engine tests demonstrated ignition using two different methods, a gas-torch and a pyrotechnic igniter. Both gas torch and pyrotechnic ignition were demonstrated at both sea-level and vacuum conditions. The rocket engine was designed to be configured with three different nozzle configurations, including a dual-bell nozzle geometry. Dual-bell nozzle tests were conducted at WSTF and engine performance data was achieved at both ambient pressure and simulated altitude conditions. Dual-bell nozzle performance data was achieved over a range of altitude conditions from 90,000 ft to 50,000 ft altitude. Thrust and propellant mass flow rates were measured in the tests for specific impulse (Isp) and C* calculations.
Author
LIQUID OXYGEN; LIQUEFIED GASES; METHANE; ROCKET ENGINES; SEA LEVEL; ALTITUDE SIMULATION; VERTICAL TAKEOFF AIRCRAFT; VERTICAL LANDING
20090032825 NASA Langley Research Center, Hampton, VA, United States
Application of CFE/POST2 for Simulation of Launch Vehicle Stage Separation
Pamadim Bandu N.; Tartabini, Paul V.; Toniolo, Matthew D.; Roithmayr, Carlos M.; Karlgaard, Christopher D.; Samareh, Jamshid A.; August 10, 2009; In English; AIAA Atmospheric Flight Mechanics Conference, 10-13 Aug. 2009, Chicago, Il, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 736466.11.01.07.54.01.01
Report No.(s): LF99-9267; AIAA Paper 2009-5842; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090032825
The constraint force equation (CFE) methodology provides a framework for modeling constraint forces and moments acting at joints that connect multiple vehicles. With implementation in Program to Optimize Simulated Trajectories II (POST 2), the CFE provides a capability to simulate end-to-end trajectories of launch vehicles, including stage separation. In this paper, the CFE/POST2 methodology is applied to the Shuttle-SRB separation problem as a test and validation case. The CFE/POST2 results are compared with STS-1 flight test data.
Author
LAUNCH VEHICLES; SIMULATION; STAGE SEPARATION; TRAJECTORIES; SPACE SHUTTLE ORBITERS
20090032918 NASA Marshall Space Flight Center, Huntsville, AL, United States
The Hurricane Imaging Radiometer (HIRAD): Instrument Status and Performance Predictions
Ruf, Christopher; Bailey, M. C.; Gross, Steven; Hood, Robbie; James, Mark; Johnson, James; Jones, Linwood; Miller, Timothy; Uhlhorn, Eric; July 13, 2009; In English; IGARSS 2009 International Geoscience and Remote Sensing Symposium, 13-17 Jul. 2009, Capetown, South Africa
Report No.(s): IGARSS Paper No. 2914; M09-0284; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090032918
The Hurricane Imaging Radiometer (HIRAD) is an innovative radiometer which offers new and unique remotely sensed observations of both extreme oceanic wind events and strong precipitation. It is based on the airborne Stepped Frequency Microwave Radiometer (SFMR) [Uhlhorn and Black, 2004]. The HIRAD instrument advances beyond the current nadir viewing SFMR to an equivalent wide-swath SFMR imager using passive microwave synthetic thinned aperture radiometer (STAR) technology [Ruf et al., 1988]. This sensor operates over 4-7 GHz, where the required tropical cyclone remote sensing physics has been validated by both SFMR and WindSat radiometer [Bettenhausen et al., 2006; Brown et al., 2006]. HIRAD incorporates a new and unique array antenna design along with several technologies successfully demonstrated by the Lightweight Rain Radiometer instrument [Ruf et al., 2002; Ruf and Principe, 2003]. HIRAD will be a compact, lightweight, low-power instrument with no moving parts that will produce wide-swath imagery of ocean winds and rain in hurricane conditions. Accurate observations of surface ocean vector winds (OVW) with high spatial and temporal resolution are required for understanding and predicting tropical cyclones. The Hurricane Imaging Radiometer (HIRAD) is an innovative architecture which offers new and unique remotely sensed observations of both extreme oceanic wind events and strong precipitation. It is based on the airborne Stepped Frequency Microwave Radiometer (SFMR), which is a proven remote sensing technique for observing tropical cyclone (TC) ocean surface wind speeds and rain rates. The proposed HIRAD instrument advances beyond the current nadir viewing SFMR to an equivalent wide-swath SFMR imager using passive microwave synthetic thinned aperture radiometer (STAR) technology combined with a a unique array antenna design. The overarching design concept of HIRAD is to combine the multi-frequency C-band observing strategy of the SFMR with STAR technology to produce a wide-swath imager. Single frequency STAR technology The Hurricane Imaging Radiometer (HIRAD) is an innovative radiometer which offers new and unique remotely sensed observations of both extreme oceanic wind events and strong precipitation. It is based on the airborne Stepped Frequency Microwave Radiometer (SFMR) [Uhlhorn and Black, 2004]. The HIRAD instrument advances beyond the current nadir viewing SFMR to an equivalent wide-swath SFMR imager using passive microwave synthetic thinned aperture radiometer (STAR) technology [Ruf et al., 1988]. This sensor operates over 4-7 GHz, where the required tropical cyclone remote sensing physics has been validated by both SFMR and WindSat radiometer [Bettenhausen et al., 2006; Brown et al., 2006]. HIRAD incorporates a new and unique array antenna design along with several technologies successfully demonstrated by the Lightweight Rain Radiometer instrument [Ruf et al., 2002; Ruf and Principe, 2003]. HIRAD will be a compact, lightweight, low-power instrument with no moving parts that will produce wide-swath imagery of ocean winds and rain in hurricane conditions. Accurate observations of surface ocean vector winds (OVW) with high spatial and temporal resolution are required for understanding and predicting tropical cyclones. The Hurricane Imaging Radiometer (HIRAD) is an innovative architecture which offers new and unique remotely sensed observations of both extreme oceanic wind events and strong precipitation. It is based on the airborne Stepped Frequency Microwave Radiometer (SFMR), which is a proven remote sensing technique for observing tropical cyclone (TC) ocean surface wind speeds and rain rates. The proposed HIRAD instrument advances beyond the current nadir viewing SFMR to an equivalent wide-swath SFMR imager using passive microwave synthetic thinned aperture radiometer (STAR) technology combined with a a unique array antenna design. The overarching design concept of HIRAD is to combine the multi-frequency C-banbserving strategy of the SFMR with STAR technology to produce a wide-swath imager. Single frequency STAR technology
Author
HURRICANES; MICROWAVE RADIOMETERS; IMAGING TECHNIQUES; SPATIAL RESOLUTION; TEMPORAL RESOLUTION; WIND (METEOROLOGY); AIRBORNE EQUIPMENT; ANTENNA ARRAYS; MARINE METEOROLOGY; REMOTE SENSING
20090032975 Gray Research, Inc., United States
Creating a Lunar EVA Work Envelope
Griffin, Brand N.; Howard, Robert; Rajulu, Sudhakar; Smitherman, David; July 12, 2009; ISSN 0148-7191; In English; 39th International Conference on Environmental Systems, 12 - 16 Jul. 2009, Savannah, GA, United States; Original contains color and black and white illustrations
Report No.(s): 09ICES-0029; M09-0134; M09-0373; Copyright; Avail.: CASI: A02, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090032975
A work envelope has been defined for weightless Extravehicular Activity (EVA) based on the Space Shuttle Extravehicular Mobility Unit (EMU), but there is no equivalent for planetary operations. The weightless work envelope is essential for planning all EVA tasks because it determines the location of removable parts, making sure they are within reach and visibility of the suited crew member. In addition, using the envelope positions the structural hard points for foot restraints that allow placing both hands on the job and provides a load path for reacting forces. EVA operations are always constrained by time. Tasks are carefully planned to ensure the crew has enough breathing oxygen, cooling water, and battery power. Planning first involves computers using a virtual work envelope to model tasks, next suited crew members in a simulated environment refine the tasks. For weightless operations, this process is well developed, but planetary EVA is different and no work envelope has been defined. The primary difference between weightless and planetary work envelopes is gravity. It influences anthropometry, horizontal and vertical mobility, and reaction load paths and introduces effort into doing "overhead" work. Additionally, the use of spacesuits other than the EMU, and their impacts on range of motion, must be taken into account. This paper presents the analysis leading to a concept for a planetary EVA work envelope with emphasis on lunar operations. There is some urgency in creating this concept because NASA has begun building and testing development hardware for the lunar surface, including rovers, habitats and cargo off-loading equipment. Just as with microgravity operations, a lunar EVA work envelope is needed to guide designers in the formative stages of the program with the objective of avoiding difficult and costly rework.
Author
EXTRAVEHICULAR ACTIVITY; EXTRAVEHICULAR MOBILITY UNITS; WEIGHTLESSNESS; TASKS; ROVING VEHICLES; MICROGRAVITY
20090033063 National Space Science and Technology Center, Huntsville, AL, United States
Simulation of Relativistic Shocks and Associated Radiation from Turbulent Magnetic Fields
Nishikawa, K.; Niemiec, J.; Medvedev, M.; Zhang, B.; Hardee, P.; Mizuno, Y.; Nordlund, A.; Frederiksen, J.; Sol, H.; Pohl, M.; Oka, M.; Hartmann, D. H.; Fishman, J. F.; June 29, 2009; In English; 4th International Conference on Numerical Modeling of Space Plasma Flows (ASTRONUM 2009), 29 Jun. - 3 Jul. 2009, Chamonix, France; Original contains color and black and white illustrations
Report No.(s): M09-0458; M09-0459; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033063
Plasma instabilities (e.g., Buneman, Weibel and other two-stream instabilities) excited in collisionless shocks are responsible for particle (electron, positron, and ion) acceleration. Using a new 3-D relativistic particle-in-cell code, we have investigated the particle acceleration and shock structure associated with an unmagnetized relativistic electron-positron jet propagating into an unmagnetized electron-positron plasma. The simulation has been performed using a long simulation system in order to study the nonlinear stages of the Weibel instability, the particle acceleration mechanism, and the shock structure. Cold jet electrons are thermalized and slowed while the ambient electrons are swept up to create a partially developed hydrodynamic (HD) like shock structure. In the leading shock, electron density increases by a factor of <_ 3.5 in the simulation frame. Strong electromagnetic fields are generated in the trailing shock and provide an emission site. We discuss the possible implication of our simulation results within the AGN and GRB context. We have calculated the time evolution of the spectrum from two electrons propagating in a uniform parallel magnetic field to verify the technique. The same technique will be used to calculate radiation from accelerated electrons (positrons) in turbulent magnetic fields generated by Weibel instability.
Author
PARTICLE ACCELERATION; RELATIVISTIC PARTICLES; WEIBEL INSTABILITY; ELECTRON DENSITY (CONCENTRATION); ELECTRON-POSITRON PLASMAS; MAGNETOHYDRODYNAMIC STABILITY; POSITRONS
Additions to the NASA Aeronautics and Space Database as of 10/01/2009
20090033079 Alabama Univ., Huntsville, AL, United States
Performance of "Waterless Concrete"
Toutanji, H. A.; Grugel, R. N.; June 29, 2009; In English; Concrete Solutions 2009, 3rd International Conference on Concrete Repair, 29 Jun. - 2 Jul. 2009, Venice, Italy; Original contains black and white illustrations
Contract(s)/Grant(s): NNM05AA22A
Report No.(s): M09-0491; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033079
Waterless concrete consists of molten elementary sulfur and aggregate. The aggregates in a lunar environment will be lunar rocks and soil. Sulfur is present on the Moon in Troilite soil (FeS) and, by oxidation of the soil, iron and sulfur can be produced. Sulfur concrete specimens were cycled between liquid nitrogen (approx.]91 C) and room temperature (^21 C) to simulate exposure to a lunar environment. Cycled and control specimens were subsequently tested in compression at room temperatures (^21 C) and ^-101 C. Test results showed that due to temperature cycling, the compressive strength of cycled specimens was 20% of those non-cycled. This reduction in strength can be attributed to the large differences in thermal coefficients of expansion of the materials constituting the concrete which promoted cracking. Similar sulfur concrete mixtures were strengthened with short and long glass fibres. The lunar regolith simulant was melted in a 25 cc Pt- Rh crucible in a Sybron Thermoline high temperature MoSi2 furnace at melting temperatures of 1450 to 1600 C for times of 30 min to i hour. Glass fibres and small rods were pulled from the melt. The glass fibres were used to reinforce sulfur concrete plated to improve the flexural strength of the sulfur concrete. Beams strengthened with glass fibres showed to exhibit an increase in the flexural strength by as much as 45%.
Author
CONCRETES; FLEXURAL STRENGTH; SULFUR; AGGREGATES; COMPRESSIVE STRENGTH; LUNAR ROCKS; HEAT TRANSFER COEFFICIENTS
20090033091 Alabama Univ., Huntsville, AL, United States
Preliminary Development and Evaluation of Lightning Jump Algorithms for the Real-Time Detection of Severe Weather
Schultz, Christopher J.; Petersen, Walter A.; Carey, Lawrence D.; July 28, 2009; In English; Southern Thunder Workshop, 28 - 30 Jul. 2009, Cocoa Beach, FL, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): NA07AANEG0284; NA08NWS4680034
Report No.(s): M09-0500; Copyright; Avail.: CASI: A04, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033091
Previous studies have demonstrated that rapid increases in total lightning activity (intracloud + cloud-to-ground) are often observed tens of minutes in advance of the occurrence of severe weather at the ground. These rapid increases in lightning activity have been termed "lightning jumps." Herein, we document a positive correlation between lightning jumps and the manifestation of severe weather in thunderstorms occurring across the Tennessee Valley and Washington D.C. A total of 107 thunderstorms were examined in this study, with 69 of the 107 thunderstorms falling into the category of non-severe, and 38 into the category of severe. From the dataset of 69 isolated non-severe thunderstorms, an average peak 1 minute flash rate of 10 flashes/min was determined. A variety of severe thunderstorm types were examined for this study including an MCS, MCV, tornadic outer rainbands of tropical remnants, supercells, and pulse severe thunderstorms. Of the 107 thunderstorms, 85 thunderstorms (47 non-severe, 38 severe) from the Tennessee Valley and Washington D.C tested 6 lightning jump algorithm configurations (Gatlin, Gatlin 45, 2(sigma), 3(sigma), Threshold 10, and Threshold 8). Performance metrics for each algorithm were then calculated, yielding encouraging results from the limited sample of 85 thunderstorms. The 2(sigma) lightning jump algorithm had a high probability of detection (POD; 87%), a modest false alarm rate (FAR; 33%), and a solid Heidke Skill Score (HSS; 0.75). A second and more simplistic lightning jump algorithm named the Threshold 8 lightning jump algorithm also shows promise, with a POD of 81% and a FAR of 41%. Average lead times to severe weather occurrence for these two algorithms were 23 minutes and 20 minutes, respectively. The overall goal of this study is to advance the development of an operationally-applicable jump algorithm that can be used with either total lightning observations made from the ground, or in the near future from space using the GOES-R Geostationary Lightning Mapper.
Author
CLOUD-TO-GROUND DISCHARGES; THUNDERSTORMS; REAL TIME OPERATION; LIGHTNING; FRONTS (METEOROLOGY); RAIN; TROPICAL REGIONS; WEATHER FORECASTING; TORNADOES
20090033092 NASA Marshall Space Flight Center, Huntsville, AL, United States
A Real-Time Microwave Camera at 24 GHz (K-Band}
Ghasr, M. T.; Baumgartner, M. A.; Clark, D.; Kharkovsky, S.; Abou-Khousa, M.; Zoughi, R.; July 26, 2009; In English; Quantitative Nondestructive Evaluation Conference (QNDE2009), 26-31 Jul. 2009, RI, United States; Original contains color illustrations
Contract(s)/Grant(s): NNX09AF81G
Report No.(s): M09-054; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033092
The objective is to design and build a real-time microwave imaging system (i.e., camera) Microwave imaging offers tremendous potential in many applications: a) Inspection of low-loss composites, radomes, etc.; b) Detection and evaluation of corrosion under paint; c) Security, contraband detection. Raster scanning is slow and requires bulky mechanical systems. A real-time and portable imaging system can be extremely useful for rapid nondestructive testing of large structures.
Author
MICROWAVE IMAGERY; CAMERAS; RASTER SCANNING; NONDESTRUCTIVE TESTS; INSPECTION; IMAGING TECHNIQUES
20090033093 NASA Marshall Space Flight Center, Huntsville, AL, United States
NanoSail-D: A Solar Sail Demonstration Mission
Johnson, Les; Whorton, Mark; Heaton, Andy; Pinson, robin; Laue, Greg; Adams, Charles; August 13, 2009; In English; 6th IAA Symposium on Realistic Near-Term Advanced Scientific Space Missions, 6-9 Jul. 2009, Aosta, Italy; Original contains color illustrations
Report No.(s): M09-0505; M09-0506; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033093
During the past decade, within the United States, NASA Marshall Space Flight Center (MSFC) was heavily engaged in the development of revolutionary new technologies for in-space propulsion. One of the major in-space propulsion technologies developed was a solar sail propulsion system. Solar sail propulsion uses the solar radiation pressure exerted by the momentum transfer of reflected photons to generate a net force on a spacecraft. To date, solar sail propulsion systems have been designed for large spacecraft in the tens to hundreds of kilograms mass range. Recently, however, MSFC has been investigating the application of solar sails for small satellite propulsion. Likewise, NASA Ames Research Center (ARC) has been developing small spacecraft missions that have a need for amass-efficient means of satisfying deorbit requirements. Hence, a synergistic collaboration was established between these two NASA field Centers with the objective of conducting a flight demonstration of solar sail technologies for small satellites. The NanoSail-D mission flew onboard the ill-fated Falcon Rocket launched August 2, 2008, and, due to the failure of that rocket, never achieved orbit. The NanoSail-D flight spare is ready for flight and a suitable launch arrangement is being actively pursued. Both the original sailcraft and the flight spare are hereafter referred to as NanoSail-D. The sailcraft consists of a sail subsystem stowed in a three-element CubeSat. Shortly after deployment of the NanoSail-D, the solar sail will deploy and mission operations will commence. This demonstration flight has two primary technical objectives: (1) to successfully stow and deploy the sail and (2) to demonstrate deorbit functionality. Given a near-term opportunity for launch on Falcon, the project was given the challenge of delivering the flight hardware in 6 mo, which required a significant constraint on flight system functionality. As a consequence, passive attitude stabilization of the spacecraft will be achieved using permanent magnets to detumble and orient the body with the magnetic field lines and then rely on atmospheric drag to passively stabilize the sailcraft in an essentially maximum drag attitude. This paper will present an introduction to solar sail propulsion systems and an overview of the NanoSail-D spacecraft.
Author
ATTITUDE CONTROL; LARGE SPACE STRUCTURES; SOLAR SAILS; PROPULSION SYSTEM CONFIGURATIONS; ATTITUDE STABILITY; RADIATION PRESSURE; PROPULSION SYSTEM PERFORMANCE; FLIGHT TESTS; SOLAR RADIATION
20090033094 NASA Marshall Space Flight Center, Huntsville, AL, United States
Systematics in the Electron Spectrum Measured by ATIC
Panov, A. D.; Zatsepin, V. I.; Sokolskaya, N. V.; Adams, J. H., Jr.; Ahn, H. S.; Bashindzhagyan, G. L.; Chang, J.; Christl, M.; Guzik, T. G.; Isbert, J.; Kim, K. C.; Kouznetsov, E. N.; Panasyuk, M. I.; Postnikov, E. B.; Seo, E.S.; Watts, J.; Wefel, J. P.; Wu, J.; July 07, 2009; In English; 31st International Cosmic Ray Conference, 7-15 Jul. 2009, Lodz, Poland; Original contains black and white illustrations
Report No.(s): M09-0516; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033094
An analysis of different parameters to separate electrons from protons in the ATIC experiment has been performed. Five separate discriminants were studied by different Monte Carlo programs, leading to a variety of results. Application to the ATIC data indicates the range of variation possible in the interpretation of the data. The results of this analysis, when compared with the published results [5], show good agreement in the most interesting region of energy (from 90 GeV to 600 GeV). The measured electron spectrum is compared with the recent data reported by Fermi/LAT, and there is no major disagreement between ATIC s results and Fermi/LAT. Finally, possible systematics-free, short energy scale features of the ATIC electron spectrum are mentioned. Keywords: ATIC, electron spectrum, fine structure
Author
FINE STRUCTURE; ENERGY SPECTRA; FREE ENERGY; ELECTRON SPECTROSCOPY
20090033095 NASA Goddard Space Flight Center, Greenbelt, MD, United States
The Energetic Trans-Iron Cosmic-ray Experiment (ENTICE)
Binns, W. R.; Adams. J. H.; Barghouty, A. F.; Christian, E. R.; Cummings, A. C.; Hams, T.; Israel, M. H.; Labrador, A. W.; Leske, R. A.; Link, J. T.; Mewwaldt, R. A.; Mitchell, J. W.; De Nolfo, G. A.; Sasaki, M.; Stone, E. C.; Waddington, C. J.; Wiedenbeck, M. E.; July 07, 2009; In English; 31st International Cosmic Ray Conference, 7-5 Jul. 2009, Lodz, Poland; Original contains color and black and white illustrations
Contract(s)/Grant(s): NNM08AA10A
Report No.(s): M09-0518; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033095
The ENTICE experiment is one of two instruments that comprise the "Orbiting Astrophysical Spectrometer in Space (OASIS)", which is presently undergoing a NASA "Astrophysics Strategic Mission Concept Study". ENTICE is designed to make high precision measurements of the abundances of individual elements from neon through the actinides and, in addition, will search for possible superheavy nuclei in the galactic cosmic rays. The ENTICE instrument utilizes silicon detectors, aerogel and acrylic Cherenkov counters, and a scintillating optical fiber hodoscope to measure the charge and energy of these ultra-heavy nuclei for energies greater than 0.5 GeV/nucleon. It is a large instrument consisting of four modules with a total effective geometrical factor of approx.20 sq m sr. Measurements made in space for a period of three years with ENTICE will enable us to determine if cosmic rays include a component of recently synthesized transuranic elements (Pu-94 and Cm-96), to measure the age of that component, and to test the model of the OB association origin of galactic cosmic rays. Additionally, these observations will enable us to study how diffusive shock acceleration of cosmic rays operates differently on interstellar grains and gas. Keywords: cosmic rays Galaxy:abundances
Author
INTERSTELLAR MATTER; NUCLEONS; ASTROPHYSICS; GALACTIC COSMIC RAYS; MISSION PLANNING; OPTICAL FIBERS; HEAVY NUCLEI; COSMIC RAYS
20090033096 Purple Mountain Observatory, Nanjing, China
Determining the Detection Efficiency and Background Level of ATIC Electron Observation from Flight Data
Chang, J.; Wu, J.; Guzik, T. G.; Wefel, J. P.; Isbert, J.; Adams, J. H., Jr.; Christl, M.; Watts, J.; Ahn, H. S.; Kim, K. C.; Seo, E. S.; Wu, J.; Bashindzhagyan, G. L.; Kouznetsov, E. N.; Panasyuk, M. I.; Sokolskaya, N. V.; Panov, A. D.; Zatsepin, V. I.; July 07, 2009; In English; 31st International Cosmic Ray Conference, 7 - 15 Jul. 2009, Lodz, Poland; Original contains black and white illustrations
Report No.(s): M09-0517; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033096
Observations of Cosmic-ray electrons are difficult due to the large flux of cosmic ray hadrons. The event selection efficiency and background levels can be estimated from flight data for the ATIC instrument. This reduces the dependence upon Monte Carlo simulations, which show differences between different codes, thereby reducing the systematic errors resulting from analyses that only use simulations. This paper discusses some of the methods used in the ATIC analysis to determine the detection efficiency and background level for the flight data.
Author
GAMMA RAYS; ESTIMATING; HIGH ENERGY ELECTRONS; SYSTEMATIC ERRORS; ELECTRONS; COSMIC RAYS
20090033097 NASA Marshall Space Flight Center, Huntsville, AL, United States
Status of the Regenerative ECLSS Water Recovery System
Carter, Donald Layne; July 12, 2009; In English; International Conference on Environmental Systems, 12 - 16 Jul. 2009, Savannah, GA, United States; Original contains color and black and white illustrations
Report No.(s): M09-0530; 2009-01-2352; No Copyright; Avail.: CASI: A02, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033097
NASA has completed the delivery of the regenerative Water Recovery System (WRS) for the International Space Station (ISS). The major assemblies included in this system are the Water Processor Assembly (WPA) and Urine Processor Assembly (UPA). This paper summarizes the final effort to deliver the hardware to the Kennedy Space Center for launch on STS-126, the on-orbit status as of April 2009, and describes some of the technical challenges encountered and lessons learned over the past year.
Author
WATER RECLAMATION; INTERNATIONAL SPACE STATION; LIFE SUPPORT SYSTEMS; SPACECRAFT LAUNCHING
20090033100 NASA Goddard Space Flight Center, Greenbelt, MD, United States
Problems Encountered During the Recertification of the GLORY Solar Array Dual Axis Gimbal Drive Actuators
Saltzman, Marc; Schepis, Jospeh P.; Bruckner, Michael J.; September 23, 2009; In English; 13th European Space Mechanisms and Tribology Symposium/European Space Agency, 23-25 Sep. 2009, Vienna, Austria; Original contains color and black and white illustrations
Copyright; Avail.: CASI: A02, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033100
The Glory observatory is the current incarnation of the Vegetation Canopy Lidar (VCL) mission spacecraft bus. The VCL spacecraft bus, having been cancelled for programmatic reasons in 2000, was nearly integrated when it was put into storage for possible future use. The Glory mission was a suitable candidate for using this spacecraft and in 2006 an effort to recertify the two axis solar array gimbal drive after its extended storage was begun. What was expected to be a simple performance validation of the two dual axis gimbal stepper motors became a serious test, diagnosis and repair task once questions arose on the flight worthiness of the hardware. A significant test program logic flow was developed which identified decisions that could be made based on the results of individual recertification tests. Without disassembling the bi-axial gimbals, beginning with stepper motor threshold voltage measurements and relating these to powered drive torque measurements, both performed at the spacecraft integrator s facility, a confusing picture of the health of the actuators came to light. Tests at the gimbal assembly level and tests of the disassembled actuators were performed by the manufacturer to validate our results and torque discrepancies were noted. Further disassembly to the component level of the actuator revealed the source of the torque loss.
Author
CANOPIES (VEGETATION); GLORY MISSION SATELLITE; BUS CONDUCTORS; OPTICAL RADAR; SOLAR ARRAYS; THRESHOLD VOLTAGE; ACTUATORS
20090033101 NASA Goddard Space Flight Center, Greenbelt, MD, United States
Insights into the Galactic Cosmic-ray Source from the TIGER Experiment
Link, Jason T.; Barbier, L. M.; Binns, W. R.; Christian, E. R.; Cummings, J. R.; Geier, S.; Israel, M. H.; Lodders, K.; Mewaldt,R. A.; Mitchell, J. W.; deNolfo, G. A.; Rauch, B. F.; Schindler, S. M.; Scott, L. M.; Streitmatter, R. E.; Stone, E. C.; Waddington, C. J.; Wiedenbeck, M. E.; July 07, 2009; In English; 31st International Cosmic Ray Conference/International Union of Pure and Applied Physics (IUPAP), 7-15 Jul. 2009, Lodz, Poland; Original contains black and white illustrations
Contract(s)/Grant(s): NNG06EO90A; NNG05WC04G; NNG05WC21G; NSF AST-0807356
Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033101
We report results from 50 days of data accumulated in two Antarctic flights of the Trans-Iron Galactic Element Recorder (TIGER). With a detector system composed of scintillators, Cherenkov detectors, and scintillating optical fibers, TIGER has a geometrical acceptance of 1.7 sq m sr and a charge resolution of 0.23 cu at Iron. TIGER has obtained abundance measurements of some of the rare galactic cosmic rays heavier than iron, including Zn, Ga, Ge, Se, and Sr, as well as the more abundant lighter elements (down to Si). The heavy elements have long been recognized as important probes of the nature of the galactic cosmic-ray source and accelerator. After accounting for fragmentation of cosmic-ray nuclei as they propagate through the Galaxy and the atmosphere above the detector system, the TIGER source abundances are consistent with a source that is a mixture of about 20% ejecta from massive stars and 80% interstellar medium with solar system composition. This result supports a model of cosmic-ray origin in OB associations previously inferred from ACE-CRIS data of more abundant lighter elements. These TIGER data also support a cosmic-ray acceleration model in which elements present in interstellar grains are accelerated preferentially compared with those found in interstellar gas.
Author
COSMIC RAYS; COSMIC DUST; INTERSTELLAR MATTER; STAR CLUSTERS; O STARS; MASSIVE STARS; INTERSTELLAR GAS; GALACTIC COSMIC RAYS; FRAGMENTATION
20090033102 NASA Langley Research Center, Hampton, VA, United States
Aerodynamic Interference Due to MSL Reaction Control System
Dyakonov, Artem A.; Schoenenberger, Mark; Scallion, William I.; VanNorman, John W.; Novak, Luke A.; Tang, Chun Y.; January 05, 2009; In English; 47th AIAA Aerospace Sciences Meeting and Exhibit, 5-8 Jan. 2009, Orlando, FL, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 857464.02.07.08
Report No.(s): LF99-7145; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033102
An investigation of effectiveness of the reaction control system (RCS) of Mars Science Laboratory (MSL) entry capsule during atmospheric flight has been conducted. The reason for the investigation is that MSL is designed to fly a lifting actively guided entry with hypersonic bank maneuvers, therefore an understanding of RCS effectiveness is required. In the course of the study several jet configurations were evaluated using Langley Aerothermal Upwind Relaxation Algorithm (LAURA) code, Data Parallel Line Relaxation (DPLR) code, Fully Unstructured 3D (FUN3D) code and an Overset Grid Flowsolver (OVERFLOW) code. Computations indicated that some of the proposed configurations might induce aero-RCS interactions, sufficient to impede and even overwhelm the intended control torques. It was found that the maximum potential for aero-RCS interference exists around peak dynamic pressure along the trajectory. Present analysis largely relies on computational methods. Ground testing, flight data and computational analyses are required to fully understand the problem. At the time of this writing some experimental work spanning range of Mach number 2.5 through 4.5 has been completed and used to establish preliminary levels of confidence for computations. As a result of the present work a final RCS configuration has been designed such as to minimize aero-interference effects and it is a design baseline for MSL entry capsule.
Author
AERODYNAMIC INTERFERENCE; COMPUTATIONAL GRIDS; SYSTEM EFFECTIVENESS; ANALYSIS (MATHEMATICS); DATA REDUCTION; FLIGHT TESTS; DYNAMIC PRESSURE
20090033104 NASA Marshall Space Flight Center, Huntsville, AL, United States
Observation and Interpretation of Energetic Neutral Hydrogen Atoms from the December 5, 2006 Solar Flare
Barghouty, A. F.; Mewaldt, R. A.; Leske, R. A.; Shih, A. Y.; Stone, E. C.; Cohen, C. M. S.; Cummings, A. C.; Labrador, A. W.; vonRosenvinge, T. T.; Wiedenbeck, M. E.; July 07, 2009; In English; 31st International Cosmic Ray Conference, 7-15 Jul. 2009, Lodz, Poland
Contract(s)/Grant(s): NAS5-03131; SA2715-26309
Report No.(s): M09-0557; Copyright; Avail.: CASI: A02, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033104
We discuss observations of energetic neutral hydrogen atoms (ENAs) from a solar flare/coronal mass ejection event reported by Mewaldt et al. (2009). The observations were made during the 5 December 2006 X9 solar flare, located at E79, by the Low Energy Telescopes (LETs) on STEREO A and B. Prior to the arrival of the main solar energetic particle (SEP) event at Earth, both LETs observed a sudden burst of 1.6 to 15 MeV particles arriving from the Sun. The derived solar emission profile, arrival directions, and energy spectrum all show that the <5 MeV particles were due to energetic neutral hydrogen atoms produced by either flare or shock-accelerated protons. RHESSI measurements of the 2.2-MeV gamma-ray line provide an estimate of the number of interacting flare-accelerated protons in this event, which leads to an improved estimate of ENA production by flare-accelerated protons. CME-driven shock acceleration is also considered. Taking into account ENA losses, we conclude that the observed ENAs must have been produced in the high corona at heliocentric distances .2 solar radii.
Author
SOLAR FLARES; GAMMA RAYS; SOLAR CORPUSCULAR RADIATION; CORONAL MASS EJECTION; ENERGETIC PARTICLES; EMISSION SPECTRA; ENERGY SPECTRA; HYDROGEN ATOMS
20090033105 NASA Langley Research Center, Hampton, VA, United States
NO PLIF Study of Hypersonic Transition Over a Discrete Hemispherical Roughness Element
Danehy, Paul M.; Bathel, Brett F.; Ivey, Christopher; Inman, Jennifer A.; Jones, Stephen B.; January 05, 2009; In English; 47th AIAA Aerospace Sciences Meeting and Exhibit, 5-8 Jan. 2009, Orlando, FL, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 599489.02.07.07.06.03
Report No.(s): LF99-7115; AIAA Paper 2009-0394; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033105
Nitric oxide (NO) planar laser-induced fluorescence (PLIF) has been use to investigate the hypersonic flow over a flat plate with and without a 2-mm (0.08-in) radius hemispherical trip. In the absence of the trip, for all angles of attack and two different Reynolds numbers, the flow was observed to be laminar and mostly steady. Boundary layer thicknesses based on the observed PLIF intensity were measured and compared with a CFD computation, showing agreement. The PLIF boundary layer thickness remained constant while the NO flowrate was varied by a factor of 3, indicating non-perturbative seeding of NO. With the hemispherical trip in place, the flow was observed to be laminar but unsteady at the shallowest angle of attack and lowest Reynolds number and appeared vigorously turbulent at the steepest angle of attack and highest Reynolds number. Laminar corkscrew-shaped vortices oriented in the streamwise direction were frequently observed to transition the flow to more turbulent structures.
Author
TRANSITION FLOW; TURBULENT FLOW; LASER INDUCED FLUORESCENCE; BOUNDARY LAYER THICKNESS; SURFACE ROUGHNESS; REYNOLDS NUMBER; HYPERSONIC FLOW; FLOW VELOCITY; COMPUTATIONAL FLUID DYNAMICS; ANGLE OF ATTACK; NITRIC OXIDE
20090033111 NASA Goddard Space Flight Center, Greenbelt, MD, United States
An Intelligent Archive Testbed Incorporating Data Mining
Ramapriyan, H.; Isaac, D.; Yang, W.; Bonnlander, B.; Danks, D.; [2009]; In English; Original contains color and black and white illustrations
Contract(s)/Grant(s): NCC5-645
Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033111
Many significant advances have occurred during the last two decades in remote sensing instrumentation, computation, storage, and communication technology. A series of Earth observing satellites have been launched by U.S. and international agencies and have been operating and collecting global data on a regular basis. These advances have created a data rich environment for scientific research and applications. NASA s Earth Observing System (EOS) Data and Information System (EOSDIS) has been operational since August 1994 with support for pre-EOS data. Currently, EOSDIS supports all the EOS missions including Terra (1999), Aqua (2002), ICESat (2002) and Aura (2004). EOSDIS has been effectively capturing, processing and archiving several terabytes of standard data products each day. It has also been distributing these data products at a rate of several terabytes per day to a diverse and globally distributed user community (Ramapriyan et al. 2009). There are other NASA-sponsored data system activities including measurement-based systems such as the Ocean Data Processing System and the Precipitation Processing system, and several projects under the Research, Education and Applications Solutions Network (REASoN), Making Earth Science Data Records for Use in Research Environments (MEaSUREs), and the Advancing Collaborative Connections for Earth-Sun System Science (ACCESS) programs. Together, these activities provide a rich set of resources constituting a value chain for users to obtain data at various levels ranging from raw radiances to interdisciplinary model outputs. The result has been a significant leap in our understanding of the Earth systems that all humans depend on for their enjoyment, livelihood, and survival. The trend in the community today is towards many distributed sets of providers of data and services. Despite this, visions for the future include users being able to locate, fuse and utilize data with location transparency and high degree of interoperability, and being able to convert data to information and usable knowledge in an efficient, convenient manner, aided significantly by automation (Ramapriyan et al. 2004; NASA 2005). We can look upon the distributed provider environment with capabilities to convert data to information and to knowledge as an Intelligent Archive in the Context of a Knowledge Building system (IA-KBS). Some of the key capabilities of an IA-KBS are: Virtual Product Generation, Significant Event Detection, Automated Data Quality Assessment, Large-Scale Data Mining, Dynamic Feedback Loop, and Data Discovery and Efficient Requesting (Ramapriyan et al. 2004).
Author
DATA MINING; EARTH OBSERVING SYSTEM (EOS); EARTH SCIENCES; EOS DATA AND INFORMATION SYSTEM; REMOTE SENSING
20090033112 California Space Education and Workforce Inst., Inc., Santa Maria, CA, United States
Human-rating Automated and Robotic Systems - (How HAL Can Work Safely with Astronauts)
Baroff, Lynn; Dischinger, Charlie; Fitts, David; July 12, 2009; In English; 39th International Conference on Environmental Systems, 12 - 16 Jul. 2009, Savannah, GA, United States; Original contains color illustrations
Report No.(s): M09-0567; 09ICES-0011; Copyright; Avail.: CASI: A02, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033112
Long duration human space missions, as planned in the Vision for Space Exploration, will not be possible without applying unprecedented levels of automation to support the human endeavors. The automated and robotic systems must carry the load of routine housekeeping for the new generation of explorers, as well as assist their exploration science and engineering work with new precision. Fortunately, the state of automated and robotic systems is sophisticated and sturdy enough to do this work - but the systems themselves have never been human-rated as all other NASA physical systems used in human space flight have. Our intent in this paper is to provide perspective on requirements and architecture for the interfaces and interactions between human beings and the astonishing array of automated systems; and the approach we believe necessary to create human-rated systems and implement them in the space program. We will explain our proposed standard structure for automation and robotic systems, and the process by which we will develop and implement that standard as an addition to NASA s Human Rating requirements. Our work here is based on real experience with both human system and robotic system designs; for surface operations as well as for in-flight monitoring and control; and on the necessities we have discovered for human-systems integration in NASA's Constellation program. We hope this will be an invitation to dialog and to consideration of a new issue facing new generations of explorers and their outfitters.
Author
ROBOTICS; HUMAN BEINGS; SYSTEMS INTEGRATION; SPACE MISSIONS; RATINGS; IN-FLIGHT MONITORING; AUTOMATIC CONTROL
20090033114 NASA Johnson Space Center, Houston, TX, United States
STS-114 Engine Cut-off Sensor Anomaly Technical Consultation Report
Wilson, Timmy R.; Kichak, Robert A.; Ungar, Eugene K.; Cherney, Robert; Rickman, Steve L.; April 2009; In English; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 869021.06.07.02.99
Report No.(s): NASA/TM-2009-215567; NESC-RP-05-125/05-045-E; L-19639; LF99-8395; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033114
The NESC consultation team participated in real-time troubleshooting of the Main Propulsion System (MPS) Engine Cutoff (ECO) sensor system failures during STS-114 launch countdown. The team assisted with External Tank (ET) thermal and ECO Point Sensor Box (PSB) circuit analyses, and made real-time inputs to the Space Shuttle Program (SSP) problem resolution teams. Several long-term recommendations resulted. One recommendation was to conduct cryogenic tests of the ECO sensors to validate, or disprove, the theory that variations in circuit impedance due to cryogenic effects on swaged connections within the sensor were the root cause of STS-114 failures.
Author
ENGINE FAILURE; SPACE TRANSPORTATION SYSTEM; LAUNCHING; CRYOGENICS; EXTERNAL TANKS; MAINTENANCE; NETWORK ANALYSIS; SYSTEM FAILURES
20090033115 NASA Langley Research Center, Hampton, VA, United States
On the Effects of Surface Roughness on Boundary Layer Transition
Choudhari, Meelan M.; Li, Fei; Chang, Chau-Lyan; Edwards, Jack; May 18, 2009; In English; IISc Centenary International Conference and Exhibition on Aerospace Engineering (ICEAE2009), 18 - 22 May 2009, Bangalore, India; Original contains color and black and white illustrations
Contract(s)/Grant(s): FA9550-0701-0191
Report No.(s): LF99-8476; Copyright; Avail.: CASI: A02, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033115
Surface roughness can influence laminar-turbulent transition in many different ways. This paper outlines selected analyses performed at the NASA Langley Research Center, ranging in speed from subsonic to hypersonic Mach numbers and highlighting the beneficial as well as adverse roles of the surface roughness in technological applications. The first theme pertains to boundary-layer tripping on the forebody of a hypersonic airbreathing configuration via a spanwise periodic array of trip elements, with the goal of understanding the physical mechanisms underlying roughness-induced transition in a high-speed boundary layer. The effect of an isolated, finite amplitude roughness element on a supersonic boundary layer is considered next. The other set of flow configurations examined herein corresponds to roughness based laminar flow control in subsonic and supersonic swept wing boundary layers. A common theme to all of the above configurations is the need to apply higher fidelity, physics based techniques to develop reliable predictions of roughness effects on laminar-turbulent transition.
Author
BOUNDARY LAYER CONTROL; FINITE ELEMENT METHOD; HYPERSONIC SPEED; LAMINAR BOUNDARY LAYER; SURFACE ROUGHNESS; SURFACE ROUGHNESS EFFECTS; TURBULENT BOUNDARY LAYER; SWEPT WINGS; FOREBODIES
20090033116 NASA Langley Research Center, Hampton, VA, United States
Possible Deficiencies in Predicting Transonic Aerodynamics on the X-43A
Labbe, Steven G.; Gilbert, Michael G.; Kehoe, Michael W.; April 2009; In English; Original contains color illustrations
Contract(s)/Grant(s): WBS 869021.05.07.04.04
Report No.(s): NASA/TM-2009-215711; NESC-RP-04-02/03-002-E; L-19650; LF99-8657; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033116
The initial X-43A flight test, June 2, 2001, resulted in a mishap and loss of the vehicle. A mishap investigation board (MIB) report and findings, including the established root cause, were publicly released on July, 23, 2003. The X-43A Flight 1 Hyper-X Launch Vehicle (HXLV) failed because the vehicle control system design was deficient for the trajectory flown due to inaccurate analytical models (Pegasus heritage and HXLV specific), which overestimated the (control) system margin ? X-43A Mishap Investigation Report, Vol. I. ? included as Reference 1. Several specific errors were noted, 1) HXLV aerodynamics ? failure to model changes to wing, fin and rudder airfoil shapes due to addition of thermal protection system (TPS); 2) Fin actuation system (FAS) modeling ? under prediction of the control surface hinge moments and FAS compliance; and 3) Parametric uncertainties ? insufficient variation in the aerodynamic, FAS and control system models. In response to the MIB findings, the X-43A program has been working RTF through an approved Corrective Action Plan (CAP) over the last two years.
Author
LAUNCH VEHICLES; FLIGHT TESTS; FAILURE; ERRORS; CONTROL SYSTEMS DESIGN; MATHEMATICAL MODELS
20090033117 NASA Marshall Space Flight Center, Huntsville, AL, United States
The Next Generation Advanced Video Guidance Sensor: Flight Heritage and Current Development
Howard, Richard T.; Bryan, Thomas C.; February 24, 2009; In English; Space, Propulsion & Energy Sciences International Forum: SPESIF-2009, 24 - 26 Feb. 2009, Huntsville, AL, United States; Original contains color and black and white illustrations
Report No.(s): M09-0273; No Copyright; Avail.: CASI: A02, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033117
The Next Generation Advanced Video Guidance Sensor (NGAVGS) is the latest in a line of sensors that have flown four times in the last 10 years. The NGAVGS has been under development for the last two years as a long-range proximity operations and docking sensor for use in an Automated Rendezvous and Docking (AR&D) system. The first autonomous rendezvous and docking in the history of the U.S. Space Program was successfully accomplished by Orbital Express, using the Advanced Video Guidance Sensor (AVGS) as the primary docking sensor. That flight proved that the United States now has a mature and flight proven sensor technology for supporting Crew Exploration Vehicles (CEV) and Commercial Orbital Transport Systems (COTS) Automated Rendezvous and Docking (AR&D). NASA video sensors have worked well in the past: the AVGS used on the Demonstration of Autonomous Rendezvous Technology (DART) mission operated successfully in "spot mode" out to 2 km, and the first generation rendezvous and docking sensor, the Video Guidance Sensor (VGS), was developed and successfully flown on Space Shuttle flights in 1997 and 1998. This paper presents the flight heritage and results of the sensor technology, some hardware trades for the current sensor, and discusses the needs of future vehicles that may rendezvous and dock with the International Space Station (ISS) and other Constellation vehicles. It also discusses approaches for upgrading AVGS to address parts obsolescence, and concepts for minimizing the sensor footprint, weight, and power requirements. In addition, the testing of the various NGAVGS development units will be discussed along with the use of the NGAVGS as a proximity operations and docking sensor.
Author
GUIDANCE SENSORS; AUTONOMOUS DOCKING; SPACE TRANSPORTATION SYSTEM FLIGHTS; ORBITAL RENDEZVOUS; SPACECRAFT DOCKING; AUTONOMY
20090033119 NASA Marshall Space Flight Center, Huntsville, AL, United States
Reefing of Quarter Spherical Ribbon Parachutes Used in the Ares I First Stage Deceleration System
Schmidt, Jason R.; McFadden, Peter G.; May 04, 2009; In English; AIAA 20th Aerodynamic Decelerator Systems Technology Conference and Seminar, 4 May 2009, Seattle, WA, United States; Original contains color illustrations
Contract(s)/Grant(s): NNM07AA75C
Report No.(s): M09-0428; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033119
This paper introduces the parachutes that have been drop tested in support of the Ares I first stage deceleration system development. The results of the tests show that the reefing ratios for these quarter spherical ribbon parachutes provide the same reefed drag area as historical conical ribbon parachutes. Two sources are investigated for properly normalizing the parachutes relative to their suspension line length, and one is found to be superior.
Author
PARACHUTES; RIBBON PARACHUTES; SYSTEMS ENGINEERING; DECELERATION; ARES 1 FIRST STAGE
20090033123 Mississippi State Univ., MS, United States
Effects of Core-Shell Rubber (CSR) Nanoparticles on the Cryogenic Fracture Toughness of CSR Modified Epoxy
Wang, Jun; Magee, Daniel; Schneider, Judy; Cannon, Seth; February 15, 2009; In English; TMS 2009 Annual Meeting and Exhibition, 15 - 19 Feb. 2009, San Francisco, CA, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): DMR-0619773; DMR-0216703
Report No.(s): M09-0310; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033123
This study investigated the effects of core-shell rubber (CSR) nanoparticles on the mechanical properties and fracture toughness of an epoxy resin at ambient and liquid nitrogen (LN2) temperatures. Varying amounts of Kane Ace(Registered TradeMark) MX130 and Kane Ace(Registered TradeMark) MX960 toughening agent were added to a commercially available EPON 862/Epikure W epoxy resin. Elastic modulus was calculated using quasi-static tensile data. Fracture toughness was evaluated by the resulting breaking energy measured in Charpy impact tests conducted on an instrumented drop tower. The size and distribution of the CSR nanoparticles were characterized using Transmission Electron Microscopy (TEM) and Small Angle X-ray Scattering (SAXS). Scanning Electron Microscopy (SEM) was used to study the fracture surface morphology. The addition of the CSR nanoparticles increased the breaking energy with negligible change in elastic modulus and ultimate tensile stress (UTS). At ambient temperature the breaking energy increased with increasing additions of the CSR nanoparticles up to 13.8wt%, while at LN2 temperatures, it reached a plateau at much lower CSR concentration.
Author
EPOXY RESINS; FRACTURE STRENGTH; RUBBER; NANOPARTICLES; TENSILE STRESS; TRANSMISSION ELECTRON MICROSCOPY
20090033131 Alabama Univ., Huntsville, AL, United States
Developing an Enhanced Lightning Jump Algorithm for Operational Use
Schultz, Christopher J.; Petersen, Walter A.; Carey, Lawrence D.; July 28, 2009; In English; Southern Thunder Workshop, 28 - 30 Jul. 2009, Cocoa Beach, FL, United States; Original contains color and black and white illustrations
Report No.(s): M09-0618; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033131
Overall Goals: 1. Build on the lightning jump framework set through previous studies. 2. Understand what typically occurs in nonsevere convection with respect to increases in lightning. 3. Ultimately develop a lightning jump algorithm for use on the Geostationary Lightning Mapper (GLM). 4 Lightning jump algorithm configurations were developed (2(sigma), 3(sigma), Threshold 10 and Threshold 8). 5 algorithms were tested on a population of 47 nonsevere and 38 severe thunderstorms. Results indicate that the 2(sigma) algorithm performed best over the entire thunderstorm sample set with a POD of 87%, a far of 35%, a CSI of 59% and a HSS of 75%.
Author
ALGORITHMS; LIGHTNING; CONVECTION
20090033134 Jacobs Engineering Group, Inc., Houston, TX, United States
The Duration of Chemical Weathering of Gusev Crater's Wishstone-Watchtower Sequence
Sutter, Brad; Ming, D. W.; Golden, D. C.; June 1, 2009; In English; Workshop on Modeling Hydrous Environments, 1 - 3 Jun. 2009, Houston, TX, United States; Original contains color illustrations
Contract(s)/Grant(s): C037-AS00-0100-MARS
Report No.(s): JSC-CN-18423; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033134
Mineralogical abundance of primary minerals versus secondary minerals, chemical mixing relationships, and elemental ratios have been used to assess the degree of aqueous alteration at Gusev Crater and Meridiani Planum. However, limited work has used Ti-normalized mass-balance analysis chemical data to quantify gains and losses of elements from altered materials as well as estimate the duration of aqueous alteration on Mars. The Ti-normalized mass-balance approach accounts for volumetric changes associated with geochemical alteration. If volumetric changes are not considered, observed geochemical trends based on un-normalized data have the potential to be misleading. Assessing gains and losses from altered materials can indicate the geochemistry of fluids involved in the alteration. Furthermore, elemental losses can be combined with dissolution rates to estimate the duration of chemical weathering. Knowledge of the duration of aqueous alteration will provide insight into the climate history of Mars as well as indicate the potential for microbial habitability. The Wishstone-Watchtower materials in Gusev Crater are suitable candidates for Ti-normalized mass-balance analysis because mixing relationships of these two materials indicate that Watchtower materials may be derived from Wishstone-like materials. The objectives of this work are to (1) employ Ti-normalized mass-balance to assess gains and losses from the Wishstone-Watchtower sequence and (2) to combine losses with laboratory dissolution rates to estimate alteration times of the Watchtower material.
Author
MARS CRATERS; GEOCHEMISTRY; MINERALOGY; MICROORGANISMS; MARS SURFACE; WEATHERING; MIXING RATIOS; CLIMATE
20090033138 NASA Ames Research Center, Moffett Field, CA, United States
The Thermal Electrical Conductivity Probe (TECP) for Phoenix
Zent, Aaron P.; Hecht, Michael H.; Cobos, Doug R.; Campbell, Gaylon S.; Campbell, Colin S.; Cardell, Greg; Foote, Marc C.; Wood, Stephen E.; Mehta, Manish; [2009]; In English; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 439654.02.01.03
Report No.(s): ARC-E-DAA-TN264; Copyright; Avail.: CASI: A04, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033138
The Thermal and Electrical Conductivity Probe (TECP) is a component of the Microscopy, Electrochemistry, and Conductivity Analyzer (MECA) payload on the Phoenix Lander. TECP will measure the temperature, thermal conductivity and volumetric heat capacity of the regolith. It will also detect and quantify the population of mobile H2O molecules in the regolith, if any, throughout the polar summer, by measuring the electrical conductivity of the regolith, as well as the dielectric permittivity. In the vapor phase, TECP is capable of measuring the atmospheric H2O vapor abundance, as well as augment the wind velocity measurements from the meteorology instrumentation. TECP is mounted near the end of the 2.3 m Robotic Arm, and can be placed either in the regolith material or held aloft in the atmosphere. This paper describes the development and calibration of the TECP. In addition, substantial characterization of the instrument has been conducted to identify behavioral characteristics that might affect landed surface operations. The greatest potential issue identified in characterization tests is the extraordinary sensitivity of the TECP to placement. Small gaps alter the contact between the TECP and regolith, complicating data interpretation. Testing with the Phoenix Robotic Arm identified mitigation techniques that will be implemented during flight. A flight model of the instrument was also field tested in the Antarctic Dry Valleys during the 2007-2008 International Polar year. 2
Author
THERMAL CONDUCTIVITY; ELECTROCHEMISTRY; ELECTRICAL RESISTIVITY; PAYLOADS; VELOCITY MEASUREMENT; SPECIFIC HEAT; PERMITTIVITY; FLIGHT INSTRUMENTS; CALIBRATING
20090033140 Triumph Aerospace Systems, Newport News, VA, United States
Technology Transfer Challenges: A Case Study of User-Centered Design in NASA's Systems Engineering Culture
Quick, Jason; July 12, 2009; In English; 39th International Conference on Environmental Systems, 12-16 Jul. 2009, Savannah, GA, United States; Original contains color illustrations
Contract(s)/Grant(s): NNM05ABSOC
Report No.(s): M09-0131; M09-0349; 09ICES-0317; M09-581; Copyright; Avail.: CASI: A04, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033140
The Upper Stage (US) section of the National Aeronautics and Space Administration's (NASA) Ares I rocket will require internal access platforms for maintenance tasks performed by humans inside the vehicle. Tasks will occur during expensive critical path operations at Kennedy Space Center (KSC) including vehicle stacking and launch preparation activities. Platforms must be translated through a small human access hatch, installed in an enclosed worksite environment, support the weight of ground operators and be removed before flight - and their design must minimize additional vehicle mass at attachment points. This paper describes the application of a user-centered conceptual design process and the unique challenges encountered within NASA's systems engineering culture focused on requirements and "heritage hardware". The NASA design team at Marshall Space Flight Center (MSFC) initiated the user-centered design process by studying heritage internal access kits and proposing new design concepts during brainstorming sessions. Simultaneously, they partnered with the Technology Transfer/Innovative Partnerships Program to research inflatable structures and dynamic scaffolding solutions that could enable ground operator access. While this creative, technology-oriented exploration was encouraged by upper management, some design stakeholders consistently opposed ideas utilizing novel, untested equipment. Subsequent collaboration with an engineering consulting firm improved the technical credibility of several options, however, there was continued resistance from team members focused on meeting system requirements with pre-certified hardware. After a six-month idea-generating phase, an intensive six-week effort produced viable design concepts that justified additional vehicle mass while optimizing the human factors of platform installation and use. Although these selected final concepts closely resemble heritage internal access platforms, challenges from the application of the user-centered process provided valuable lessons for improving future collaborative conceptual design efforts.
Author
SYSTEMS ENGINEERING; HUMAN FACTORS ENGINEERING; NASA PROGRAMS; TECHNOLOGY TRANSFER; ARES 1 UPPER STAGE
20090033142 NASA Langley Research Center, Hampton, VA, United States
Tensile Properties and Microstructure of Inconel 718 Fabricated with Electron Beam Freeform Fabrication (EBF(sup 3))
Bird, R. Keith; Hibberd, Joshua; September 2009; In English; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 561581.02.08.07.15.03
Report No.(s): NASA/TM-2009-215929; L-19731; LF99-9226; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033142
Electron beam freeform fabrication (EBF3) direct metal deposition processing was used to fabricate two Inconel 718 single-bead-width wall builds and one multiple-bead-width block build. Specimens were machined to evaluate microstructure and room temperature tensile properties. The tensile strength and yield strength of the as-deposited material from the wall and block builds were greater than those for conventional Inconel 718 castings but were less than those for conventional cold-rolled sheet. Ductility levels for the EBF3 material were similar to those for conventionally-processed sheet and castings. An unexpected result was that the modulus of the EBF3-deposited Inconel 718 was significantly lower than that of the conventional material. This low modulus may be associated with a preferred crystallographic orientation resultant from the deposition and rapid solidification process. A heat treatment with a high solution treatment temperature resulted in a recrystallized microstructure and an increased modulus. However, the modulus was not increased to the level that is expected for Inconel 718.
Author
INCONEL (TRADEMARK); ELECTRON BEAMS; FABRICATION; DEPOSITION; METALLIZING; RAPID QUENCHING (METALLURGY); HEAT TREATMENT; TENSILE STRENGTH; HEAT OF SOLUTION
20090033144 Blackhawk Management Corp., Houston, TX, United States
Improving the Estimates of International Space Station (ISS) Induced K-Factor Failure Rates for On-Orbit Replacement Unit (ORU) Supportability Analyses
Anderson, Leif F.; Harrington, Sean P.; Omeke, Ojei, II; Schwaab, Douglas G.; September 14, 2009; In English; AIAA SPACE 2009 Conference and Exposition, 14-17 Sep. 2009, Pasadena, CA, United States; Original contains color illustrations
Contract(s)/Grant(s): NAS5-10000
Report No.(s): JSC-CN-18626; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033144
This is a case study on revised estimates of induced failure for International Space Station (ISS) on-orbit replacement units (ORUs). We devise a heuristic to leverage operational experience data by aggregating ORU, associated function (vehicle sub -system), and vehicle effective' k-factors using actual failure experience. With this input, we determine a significant failure threshold and minimize the difference between the actual and predicted failure rates. We conclude with a discussion on both qualitative and quantitative improvements the heuristic methods and potential benefits to ISS supportability engineering analysis.
Author
FAILURE; INTERNATIONAL SPACE STATION; HEURISTIC METHODS; ESTIMATES; SYSTEMS ENGINEERING; FAILURE MODES; ANALOG DATA
Additions to the NASA Aeronautics and Space Database as of 10/02/2009
20090033478 NASA Johnson Space Center, Houston, TX, United States
Cratering Equations for Zinc Orthotitanate Coated Aluminum
Hyde, James; Christiansen, Eric; Liou, Jer-Chyi; Ryan, Shannon; [2009]; In English; 11th Hypervelocity Impact Symposium: Hypervelocity Phenomenology Studies, 11-14 Apr. 2010, Freiburg, Germany; Original contains color illustrations
Report No.(s): JSC-CN-18615; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033478
The final STS-125 servicing mission (SM4) to the Hubble Space Telescope (HST) in May of 2009 saw the return of the 2nd Wide Field Planetary Camera (WFPC2) aboard the shuttle Discovery. This hardware had been in service on HST since it was installed during the SM1 mission in December of 1993 yielding one of the longest low Earth orbit exposure times (15.4 years) of any returned space hardware. The WFPC2 is equipped with a 0.8 x 2.2 m radiator for thermal control of the camera electronics (Figure 1). The space facing surface of the 4.1 mm thick aluminum radiator is coated with Z93 zinc orthotitanate thermal control paint with a nominal thickness of 0.1 0.2 mm. Post flight inspections of the radiator panel revealed hundreds of micrometeoroid/orbital debris (MMOD) impact craters ranging in size from less than 300 to nearly 1000 microns in diameter. The Z93 paint exhibited large spall areas around the larger impact sites (Figure 2) and the craters observed in the 6061-T651 aluminum had a different shape than those observed in uncoated aluminum. Typical hypervelocity impact craters in aluminum have raised lips around the impact site. The craters in the HST radiator panel had suppressed crater lips, and in some cases multiple craters were present instead of a single individual crater. Humes and Kinard observed similar behavior after the WFPC1 post flight inspection and assumed the Z93 coating was acting like a bumper in a Whipple shield. Similar paint behavior (spall) was also observed by Bland2 during post flight inspection of the International Space Station (ISS) S-Band Antenna Structural Assembly (SASA) in 2008. The SASA, with similar Z93 coated aluminum, was inspected after nearly 4 years of exposure on the ISS. The multi-crater phenomena could be a function of the density, composition, or impact obliquity angle of the impacting particle. For instance, a micrometeoroid particle consisting of loosely bound grains of material could be responsible for creating the multiple craters. Samples were obtained from the HST largest craters for examination by electron microscope equipped with x-ray spectrometers to determine impactor source (micrometeoroid or orbital debris). In an attempt to estimate the MMOD particle diameters that produced these craters, this paper will present equations for spall diameter, crater depth and crater diameter in Z93 coated aluminum. The equations will be based on hypervelocity impact tests of Z93 painted aluminum at the NASA White Sands Test Facility. Equations inputs for velocities beyond the testable regime are expected from hydrocode simulations of Z93 coated aluminum using CTH and ANSYS AUTODYN.
Author
CRATERING; ZINC; COATINGS; ALUMINUM; HUBBLE SPACE TELESCOPE; SUPERHIGH FREQUENCIES; IMPACT TESTS; SPACE DEBRIS; HYPERVELOCITY IMPACT
Additions to the NASA Aeronautics and Space Database as of 10/05/2009
20090033637 NASA Dryden Flight Research Center, Edwards, CA, United States
UAV Research, Operations, and Flight Test at the NASA Dryden Flight Research Center
Cosentino, Gary B.; August 26, 2009; In English; UCSD Seminar, 26 Aug. 2009, San Diego, CA, United States; Original contains color illustrations
Report No.(s): DFRC-1055; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033637
This slide presentation reviews some of the projects that have extended NASA Dryden's capabilities in designing, testing, and using Unmanned Aerial Vehicles (UAV's). Some of the UAV's have been for Science and experimental applications, some have been for flight research and demonstration purposes, and some have been small UAV's for other customers.
CASI
FLIGHT TESTS; AIRCRAFT DESIGN; PILOTLESS AIRCRAFT; UNMANNED AIRCRAFT SYSTEMS; RESEARCH AIRCRAFT
20090033640 NASA Marshall Space Flight Center, Huntsville, AL, United States
Characterizing the Effect of Shock on Isotopic Ages 2 Mg-Suite Troctolite Major Elements
Edmunson, Jennifer; Cohen, Barbara; July 13, 2009; In English; 72nd Annual Meeting of the Meteoritical Society, 13-18 Jul. 2009, Nancy, France
Report No.(s): M09-0460; M09-0553; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033640
Two troctolites from the lunar magnesium suite (Mg-suite), 76335 and 76535, have Sm-147-ND-143 and Rb-87- Sr-87 ages that do not indicate the same age for their respective sample. In the case of 76335, the Sm-147-ND-143 age is 4278 +/- 60 Ma, but the Rb-87-Sr-87 data does not reveal an isochron]. For 76535, the Sm-147-ND-143 age is significantly younger (4260 +/- 60 Ma) than the Rb-87- Sr-87 age (4570 +/- 70 Ma, Lambda = 1.402x10(exp -11)). This study was designed to discover why the Sm-147-ND-143 and Rb-87-Sr-87 ages did not match for each individual sample.
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ISOTOPES; GEOCHRONOLOGY; ISOTOPE RATIOS; METEORITIC COMPOSITION
20090033641 NASA Stennis Space Center, Stennis Space Center, MS, United States
A3 Subscale Rocket Hot Fire Testing
Saunders, G. P.; Yen, J.; August 03, 2009; In English; 45th AIAA JPC, 3-5 Aug. 2009, Denver, CO, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): NNS04AB67T
Report No.(s): SSTI-8080-0034; Copyright; Avail.: CASI: A02, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033641
This paper gives a description of the methodology and results of J2-X Subscale Simulator (JSS) hot fire testing supporting the A3 Subscale Diffuser Test (SDT) project at the E3 test facility at Stennis Space Center, MS (SSC). The A3 subscale diffuser is a geometrically accurate scale model of the A3 altitude simulating rocket test facility. This paper focuses on the methods used to operate the facility and obtain the data to support the aerodynamic verification of the A3 rocket diffuser design and experimental data quantifying the heat flux throughout the facility. The JSS was operated at both 80% and 100% power levels and at gimbal angle from 0 to 7 degrees to verify the simulated altitude produced by the rocket-rocket diffuser combination. This was done with various secondary GN purge loads to quantify the pumping performance of the rocket diffuser. Also, special tests were conducted to obtain detailed heat flux measurements in the rocket diffuser at various gimbal angles and in the facility elbow where the flow turns from vertical to horizontal upstream of the 2nd stage steam ejector.
Author
ROCKET TEST FACILITIES; ALTITUDE TESTS; SIMULATION; LOADS (FORCES); EJECTORS; PURGING; SCALE MODELS
20090033643 NASA Ames Research Center, Moffett Field, CA, United States
Analysis of Sting Balance Calibration Data Using Optimized Regression Models
Ulbrich, Norbert; Bader, Jon B.; August 02, 2009; In English; 45th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, 2-5 Aug. 2009, Denver, CO, United States; Original contains color illustrations
Contract(s)/Grant(s): NNA04BA85C
Report No.(s): ARC-E-DAA-TN259; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033643
Calibration data of a wind tunnel sting balance was processed using a search algorithm that identifies an optimized regression model for the data analysis. The selected sting balance had two moment gages that were mounted forward and aft of the balance moment center. The difference and the sum of the two gage outputs were fitted in the least squares sense using the normal force and the pitching moment at the balance moment center as independent variables. The regression model search algorithm predicted that the difference of the gage outputs should be modeled using the intercept and the normal force. The sum of the two gage outputs, on the other hand, should be modeled using the intercept, the pitching moment, and the square of the pitching moment. Equations of the deflection of a cantilever beam are used to show that the search algorithm s two recommended math models can also be obtained after performing a rigorous theoretical analysis of the deflection of the sting balance under load. The analysis of the sting balance calibration data set is a rare example of a situation when regression models of balance calibration data can directly be derived from first principles of physics and engineering. In addition, it is interesting to see that the search algorithm recommended the same regression models for the data analysis using only a set of statistical quality metrics.
Author
CALIBRATING; REGRESSION ANALYSIS; WIND TUNNEL APPARATUS; MEASURING INSTRUMENTS; CANTILEVER BEAMS; DEFLECTION; PITCHING MOMENTS; MATHEMATICAL MODELS; LOADS (FORCES)
Additions to the NASA Aeronautics and Space Database as of 10/06/2009
20090033663 NASA Langley Research Center, Hampton, VA, United States
NASA Aerosciences Perspective on Proposed De-Scope of Ares I-X Development Flight Instrumentation
Schuster, David M.; August 2009; In English; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 869021.01.07.01.01
Report No.(s): NASA/TM-2009-215909; NESC-RP-08-19/08-00454; L-19744; LF99-9312; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033663
This position paper is written as a result of a number of emails and a presentation that have recently been circulated concerning the potential reduction of Development Flight Instrumentation (DFI) to be included on the Ares I-X flight test vehicle. A reduction in instrumentation has been proposed presumably to reduce project costs and relieve project schedule pressures. This proposal has generated a significant amount of discussion on both sides of the issue, primarily from those within the project. The intention here is to provide a perspective on this issue from outside the mainline project.
Author
AEROSPACE SCIENCES; FLIGHT TEST VEHICLES; FLIGHT INSTRUMENTS
20090033665 NASA Johnson Space Center, Houston, TX, United States
Ares I-X Vibroacoustic Environments
Larsen, Curtis E.; Schuster, David M.; Kaufman, Daniel S.; August 2009; In English; Original contains black and white illustrations
Contract(s)/Grant(s): WBS 869021.03.07.01.05
Report No.(s): NASA/TM-2009-215910; NESC-RP-08-70/08-00456; L-19745; LF99-9313; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033665
This paper provides a summary of the NASA Engineering and Safety Center (NESC) team recommendations and observations following participation with the Ares I-X Vibroacoustic (VA) Environments Panel in meetings at the Kennedy Space Center (KSC) and the Marshall Space Flight Center (MSFC) in March and April 2008, respectively.
Author
VIBRATIONAL STRESS; ACOUSTICS; FLIGHT TESTS; SYSTEMS ENGINEERING; CONFIGURATION MANAGEMENT
20090033666 NASA Langley Research Center, Hampton, VA, United States
Review of the Constellation Level II Safety, Reliability, and Quality Assurance (SR&QA) Requirements Documents during Participation in the Constellation Level II SR&QA Forum
Cameron, Kenneth D.; Gentz, Steven J.; Beil, Robert J.; Minute, Stephen A.; Currie, Nancy J.; Scott, Steven S.; Thomas, Walter B., III; Smiles, Michael D.; Schafer, Charles F.; Null, Cynthia H.; Bay, P. Michael; August 2009; In English; Original contains black and white illustrations
Contract(s)/Grant(s): WBS 869021.07.07.07.99
Report No.(s): NASA/TM-2009-215914; NESC-RP-08-86/08-00476; L-19749; LF99-9326; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033666
At the request of the Exploration Systems Mission Directorate (ESMD) and the Constellation Program (CxP) Safety, Reliability; and Quality Assurance (SR&QA) Requirements Director, the NASA Engineering and Safety Center (NESC) participated in the Cx SR&QA Requirements forum. The Requirements Forum was held June 24-26; 2008, at GRC's Plum Brook Facility. The forums purpose was to gather all stakeholders into a focused meeting to help complete the process of refining the CxP to refine its Level II SR&QA requirements or defining project-specific requirements tailoring. Element prime contractors had raised specific questions about the wording and intent of many requirements in areas they felt were driving costs without adding commensurate value. NESC was asked to provide an independent and thorough review of requirements that contractors believed were driving Program costs, by active participation in the forum. This document contains information from the forum.
Author
CONSTELLATION PROGRAM; QUALITY CONTROL; REQUIREMENTS; RELIABILITY; COSTS; SAFETY
20090033668 NASA Johnson Space Center, Houston, TX, United States
Space Life Sciences Social Innovation
Llewellyn, Alicia; [2009]; In English; Original contains color illustrations
Report No.(s): JSC-CN-18822; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033668
This slide presentation reviews some of the problems in the world, that NASA is working to solve. It reviews some of the problems that NASA has solved in the past, and is working to solve now. Particularly of interest are some of the problems related to medical delivery in rural and remote areas.
CASI
LIFE SCIENCES; PROBLEM SOLVING; MEDICAL SERVICES
20090033672 NASA Marshall Space Flight Center, Huntsville, AL, United States
Application of Digital Radiography to Weld Inspection for the Space Shuttle External Fuel Tank
Ussery, Warren; July 20, 2009; In English; American Society for Nondestructive Testing (ASNT) Digital Imaging 12th, 20-22, Jul. 2009, Mashantucket, CT, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): NAS8-00016
Report No.(s): M09-0598; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033672
This slide presentation reviews NASA's use of digital radiography to inspect the welds of the external tanks used to hold the cryogenic fuels for the Space Shuttle Main Engines. NASA has had a goal of replacing a significant portion of film used to inspect the welds, with digital radiography. The presentation reviews the objectives for converting to a digital system from film, the characteristics of the digital system, the Probability of detection study, the qualification and implementation of the system.
CASI
DIGITAL SYSTEMS; EXTERNAL TANKS; RADIOGRAPHY; WELDED JOINTS; FAULT DETECTION
20090033675 NASA Marshall Space Flight Center, Huntsville, AL, United States
The Crop Evaluation Research for Environmental Strategies (CERES) Remote Sensing 2008 Project Activities
Casas, Joseph C.; Glaser, John A.; Copenhaver, Kenneth L.; May, George; July 05, 2009; In English; International Symposium on Space Technology and Science, 5-12 Jul. 2009, Tsukuba, Japan
Report No.(s): M09-0564; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033675
In recent years, the use of Plant Incorporated Protectant (PIP) corn by American producers has been increasing dramatically. PIP corn contains genetically inserted traits that produce toxins in the plant that provide narrowly targeted protection against specific insect pests. The plant producing t oxms can offer significant reductions in the application of broad -spectrum pesticides that have ecological and human health consequences. PIP corn as a percentage of total corn acreage planted in the US is expected to continue to increase as these protective traits are "stacked" with other desirable traits by seed companies, and producers are seeing considerable increases in corn yield as a result. The introduction of corn as a bio-fuel source for ethanol has increased production by over 6 million hectares in 2007. The United States Environmental Protection Agency (USEPA), which is responsible for the registration of PIP crops under the Federal Insecticide, Fungicide and Rodenticide Act, views the use of PIP corn as positive. Broad spectrum pesticide use has declined since the PIP traits have been introduced. As the agricultural landscape sees a higher percentage of corn acres using the PIP technology, the risk of the targeted insect pest populations developing resistance to the toxins, thereby rendering the in will increase as well. This result would negate the effectiveness of the PIP corn traits and could reduce production of a US field corn crop valued at $33 billion dollars in 2006 and place US food and now energy security at risk. Concerns over insect pest resistance development to PIP traits have led the USEPA to team with NASA and the Institute for Technology Development (ITD) to develop geo-spatial technologies designed to proactively monitor the corn production landscape for insect pest infestation and possible resistance development. USEPA resistance management simulation models are combined with NASA remote sensi ng products to monitor the corn landscape for resistance development. The two agencies have entered into an agreement which could potentially lead to the development of next generation NASA sensors that will more specifically address the requirements of the USEPA's resistance development strategy and offer opportunities to study the ever changing ecosystem complexities. The USEPA/NASA/ITD team has developed a broad research project entitled CERES (Crop Evaluation Research for Environmental Strategies). CERES is a research effort leading to decision support system tools that are designed to integrate multi-resolution NASA remote sensing data products and USEPA geo -spatial models to monitor the potential for insect pest resistance development from the regional to the landscape and then to the field level.
Author
ECOSYSTEMS; REMOTE SENSING; FARM CROPS; ENVIRONMENT PROTECTION; DECISION SUPPORT SYSTEMS; ETHYL ALCOHOL; INSECTICIDES; PROTECTION; AGRICULTURE
20090033676 NASA Marshall Space Flight Center, Huntsville, AL, United States
The 50 Constellation Priority Sites
Noble, S.; Joosten, K.; Eppler, D.; Gruener, J.; Mendell, W.; French, R.; Plescia, J.; Spudis, P.; Wargo, M.; Robinson, M.; Lucey, P.; July 21, 2009; In English; Lunar Science Forum, 21-23 Jul. 2009, Mountain View, CA, United States; Original contains color illustrations
Report No.(s): M09-0644; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033676
The Constellation program (CxP) has developed a list of 50 sites of interest on the Moon which will be targeted by the LRO narrow angle camera. The list has also been provided to the M~ team to supplement their targeting list. This list does not represent a "site selection" process; rather the goal was to find "representative" sites and terrains to understand the range of possible surface conditions for human lunar exploration to aid engineering design and operational planning. The list compilers leveraged heavily on past site selection work (e.g. Geoscience and a Lunar Base Workshop - 1988, Site Selection Strategy for a Lunar Outpost - 1990, Exploration Systems Architecture Study (ESAS) - 2005). Considerations included scientific, resource utilization, and operational merits, and a desire to span lunar terrain types. The targets have been organized into two "tiers" of 25 sites each to provide a relative priority ranking in the event of mutual interference. A LEAG SAT (special action team) was established to validate and recommend modifications to the list. This SAT was chaired by Dr. Paul Lucey. They provided their final results to CxP in May. Dr. Wendell Mendell will organize an on-going analysis of the data as they come down to ensure data quality and determine if and when a site has sufficient data to be retired from the list. The list was compiled using the best available data, however, it is understood that with the flood of new lunar data, minor modifications or adjustments may be required.
Author
CONSTELLATION PROGRAM; MOON; PLANNING; LUNAR SURFACE; SELENOLOGY; LUNAR LANDING SITES
20090033680 NASA Marshall Space Flight Center, Huntsville, AL, United States
Lunar Mapping and Modeling Project
Noble, Sarah K.; French, Raymond; Nall,Mark; Muery, Kimberly; July 21, 2009; In English; Lunar Science Forum, 21-23 Jul. 2009, Mountain View, CA, United States; Original contains color illustrations
Report No.(s): M09-0645; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033680
The Lunar Mapping and Modeling Project (LMMP) has been created to manage the development of a suite of lunar mapping and modeling products that support the Constellation Program (CxP) and other lunar exploration activities, including the planning, design, development, test and operations associated with lunar sortie missions, crewed and robotic operations on the surface, and the establishment of a lunar outpost. The project draws on expertise from several NASA and non-NASA organizations (MSFC, ARC, GSFC, JPL, CRREL and USGS). LMMP will utilize data predominately from the Lunar Reconnaissance Orbiter, but also historical and international lunar mission data (e.g. Apollo, Lunar Orbiter, Kaguya, Chandrayaan-1), as available and appropriate, to meet Constellation s data needs. LMMP will provide access to this data through a single, common, intuitive and easy to use NASA portal that transparently accesses appropriately sanctioned portions of the widely dispersed and distributed collections of lunar data, products and tools. LMMP will provide such products as DEMs, hazard assessment maps, lighting maps and models, gravity models, and resource maps. We are working closely with the LRO team to prevent duplication of efforts and ensure the highest quality data products. While Constellation is our primary customer, LMMP is striving to be as useful as possible to the lunar science community, the lunar education and public outreach (E/PO) community, and anyone else interested in accessing or utilizing lunar data.
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CONSTELLATION PROGRAM; LUNAR MAPS; LUNAR SURFACE; MAPPING
20090033682 NASA Marshall Space Flight Center, Huntsville, AL, United States
The Uppermost Surface of the Moon
Noble, Sarah K.; July 21, 2009; In English; Lunar Science Forum, 21-23 Jul. 2009, Mountain View, CA, United States; Original contains color illustrations
Report No.(s): M09-0646; No Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033682
The Ap16 Clam shell Sampling Devices (CSSDs) were designed to sample the uppermost surface of lunar soil. The two devices used beta cloth (69003) and velvet (69004) to collect soil from the top 100 and 500 micrometers of the soil, respectively. Due to the difficulty of the sampling method, little material was collected and as a result little research has been done on these samples. Initial studies attempted to look at the material which had fallen off of the fabrics and was subsequently collected from inside the sample containers. However, this material was highly fractionated and did not provide an adequate picture of the uppermost surface. Recently, samples were obtained directly from the beta cloth using carbon tape. While still fractionated, these samples provide a unique glimpse into the undisturbed soil exposed at the lunar surface.
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LUNAR SOIL; LUNAR SURFACE; MOON; SOIL SAMPLING; FABRICS; GRANULAR MATERIALS
20090033684 NASA Glenn Research Center, Cleveland, OH United States
Moisture-Induced Delayed Alumina Scale Spallation on a Ni(Pt)Al Coating
Smialek, James L; Apr. 2009; In English
Contract(s)/Grant(s): FA8650-06-2-5211-AO15Proj-2241
Report No.(s): AD-A502974; AFRL-RX-WP-TP-2009-4150; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033684
http://hdl.handle.net/100.2/ADA502974
Delayed scale failure was examined for samples of a Ni(Pt)Al-coated CMSX4 single crystal superalloy, cyclically oxidized at 1150 degrees C for 2000 hr. One sample exhibited accentuated coating grain boundary wrinkling, initiating local alumina scale spallation to bare metal, resulting in a final weight loss of 3.3 milligrams/(square centimeter). Spallation under ambient conditions was monitored with time after cooldown and was found to continue for times up to 24 hr, producing up to 0.05 milligrams/(square centimeter) additional loss for each hold, and accumulating 0.7 milligrams/(square centimeter) (20% of the total) over the course of the test. After test termination, water immersion produced an additional 0.15 milligrams/(square centimeter) loss. (A duplicate sample produced much less wrinkling and time dependent spalling, maintaining a net weight gain). The results are consistent with the general phenomena of moisture-induced delayed spallation (MIDS) of mature, distressed alumina scales formed on oxidation resistant MAl alloys. Relative ambient humidity is discussed as the factor controlling adsorbed moisture, reaction with the substrate, and hydrogen effects on interface strength.
Author
ALUMINUM ALLOYS; ALUMINUM OXIDES; COATING; DELAY; HEAT RESISTANT ALLOYS; MOISTURE; NICKEL ALLOYS; PLATINUM ALLOYS; SPALLATION
20090033685 NASA Marshall Space Flight Center, Huntsville, AL, United States
Spatial Analysis of Environmental Factors Related to Lyme Disease in Alabama by Means of NASA Earth Observation Systems
Renneboog, Nathan; Capilouto, Emily G.; Firsing, Stephen L., III; Levy, Kyle; McAllister, Marilyn; Roa, Kathryn; Setia,Shveta; Xie, Lili; Burnett, Donna; Luvall, Jeffrey C.; July 26, 2009; In English; (POSTER) UAB DEVELOP Student Poster for Summer '09/DEVELOP Stakeholders meeting, 29 Jul. 2009, Birmingham, AL, United States; Original contains color illustrations
Report No.(s): M09-0656; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033685
This slide presentation reviews the epidemiology of Lyme Disease that accounts for more than 95% or vector borne diseases in the United States. The history, symptoms and the life cycle of the tick, the transmitting agent of Lyme Disease, a map that shows the cases reported to the CDC between1990 and 2006 and the number of cases in Alabama by year from 1986 to 2007. A NASA project is described, the goals of which are to (1) Demonstrate the presence of the chain of infection of Lyme disease in Alabama (2) Identify areas with environmental factors that support tick population using NASA Earth Observation Systems data in selected areas of Alabama and (3) Increase community awareness of Lyme disease and recommend primary and secondary prevention strategies. The remote sensing methods included: Analyzed Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and DigitalGlobe Quickbird satellite imagery from summer months and Performed image analyses in ER Mapper 7.1. Views from the ASTER and Quickbird land cover are shown, the Normalized Difference Vegetation Index (NDVI) algorithm was applied to all ASTER and Quickbird imagery. The use of the images to obtain the level of soil moisture is reviewed, and this analysis was used along with the NDVI, was used to identify the areas that support the tick population.
CASI
EARTH OBSERVATIONS (FROM SPACE); INFECTIOUS DISEASES; REMOTE SENSING; SATELLITE IMAGERY; SIGNS AND SYMPTOMS; IMAGE ANALYSIS; EARTH OBSERVING SYSTEM (EOS); INSECTS
20090033695 NASA Langley Research Center, Hampton, VA, United States
Shuttle Ground Support Equipment (GSE) T-0 Umbilical to Space Shuttle Program (SSP) Flight Elements Consultation
Wilson, Timmy R.; Kichak, Robert A.; McManamen, John P.; Kramer-White, Julie; Raju, Ivatury S.; Beil, Robert J.; Weeks, John F.; Elliott, Kenny B.; June 2009; In English; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 869021.05.07.04.99
Report No.(s): NASA/TM-2009-215753; NESC-RP-07-01/05-012-E; LF99-8879; No Copyright; Avail.: CASI: A11, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033695
The NASA Engineering and Safety Center (NESC) was tasked with assessing the validity of an alternate opinion that surfaced during the investigation of recurrent failures at the Space Shuttle T-0 umbilical interface. The most visible problem occurred during the Space Transportation System (STS)-112 launch when pyrotechnics used to separate Solid Rocket Booster (SRB) Hold-Down Post (HDP) frangible nuts failed to fire. Subsequent investigations recommended several improvements to the Ground Support Equipment (GSE) and processing changes were implemented, including replacement of ground-half cables and connectors between flights, along with wiring modifications to make critical circuits quad-redundant across the interface. The alternate opinions maintained that insufficient data existed to exonerate the design, that additional data needed to be gathered under launch conditions, and that the interface should be further modified to ensure additional margin existed to preclude failure. The results of the assessment are contained in this report.
Author
GROUND SUPPORT EQUIPMENT; SPACE SHUTTLES; CONNECTORS; SPACE SHUTTLE BOOSTERS; SPACE TRANSPORTATION SYSTEM FLIGHTS; LAUNCHING; PYROTECHNICS
20090033697 NASA Dryden Flight Research Center, Edwards, CA, United States
Solder Joint Health Monitoring Testbed
Delaney, Michael M.; Flynn, James G.; Browder, Mark E.; August 31, 2009; In English; Military/Aerospace Programmable Logic Device 2009 (MAPLD 2009), 31 Aug. - 3 Sep. 2009, Greenbelt, MD, United States; Original contains color and black and white illustrations
Report No.(s): DFRC-1054; No Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033697
A method of monitoring the health of selected solder joints, called SJ-BIST, has been developed by Ridgetop Group Inc. under a Small Business Innovative Research (SBIR) contract. The primary goal of this research program is to test and validate this method in a flight environment using realistically seeded faults in selected solder joints. An additional objective is to gather environmental data for future development of physics-based and data-driven prognostics algorithms. A test board is being designed using a Xilinx FPGA. These boards will be tested both in flight and on the ground using a shaker table and an altitude chamber.
Derived from text
SYSTEMS HEALTH MONITORING; SOLDERED JOINTS; ALGORITHMS; SYSTEMS ENGINEERING
Additions to the NASA Aeronautics and Space Database as of 10/07/2009
20090033727 NASA Ames Research Center, Moffett Field, CA, United States
STS-107 Debris Characterization Using Re-entry Imaging
Raiche, George A.; January 15, 2009; In English; STS-107 Debris Characterization Using Re-entry Imaging, 15 Jan. 2005, Hilo, HI, United States; Original contains color and black and white illustrations
Report No.(s): ARC-E-DAA-TN337; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033727
Analysis of amateur video of the early reentry phases of the Columbia accident is discussed. With poor video quality and little theoretical guidance, the analysis team estimated mass and acceleration ranges for the debris shedding events observed in the video. Camera calibration and optical performance issues are also described.
Author
DEBRIS; IMAGING TECHNIQUES; REENTRY; COLUMBIA (ORBITER); SPACECRAFT BREAKUP; WRECKAGE
20090033728 NASA Ames Research Center, Moffett Field, CA, United States
Shock Layer Radiation Measurements and Analysis for Mars Entry
Bose, Deepak; Grinstead, Jay Henderson; Bogdanoff, David W.; Wright, Michael J.; September 30, 2009; In English; 3rd International Workshop on Radiation of High Temperature Gases in Atmospheric Entry, 30 Sep. - 3 Oct. 2008, Heraklion, Greece; Original contains black and white illustrations
Contract(s)/Grant(s): NNA4BC25C; M-ISP-03-18
Report No.(s): ARC-E-DAA-TN315; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033728
NASA's In-Space Propulsion program is supporting the development of shock radiation transport models for aerocapture missions to Mars. A comprehensive test series in the NASA Antes Electric Arc Shock Tube facility at a representative flight condition was recently completed. The facility optical instrumentation enabled spectral measurements of shocked gas radiation from the vacuum ultraviolet to the near infrared. The instrumentation captured the nonequilibrium post-shock excitation and relaxation dynamics of dispersed spectral features. A description of the shock tube facility, optical instrumentation, and examples of the test data are presented. Comparisons of measured spectra with model predictions are also made.
Author
SHOCK LAYERS; MARS MISSIONS; NEAR INFRARED RADIATION; FAR ULTRAVIOLET RADIATION; SPECTRUM ANALYSIS; RADIATION TRANSPORT; OPTICAL MEASUREMENT
20090033730 NASA Johnson Space Center, Houston, TX, United States
Laser Peening Effects on Friction Stir Welding
Hatameleh, Omar; September 09, 2009; In English; 7th Symposium in Optics in Industry, 9-12 Sep. 2009, Guadalajara, Mexico; Original contains color and black and white illustrations
Report No.(s): JSC-CN-18754; No Copyright; Avail.: CASI: A04, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033730
The laser peening process can result in considerable improvement to crack initiation, propagation, and mechanical properties in FSW which equates to longer hardware service life Processed hardware safety is improved by producing higher failure tolerant hardware, and reducing risk. Lowering hardware maintenance cost produces longer hardware service life, and lower hardware down time. Application of this proposed technology will result in substantial benefits and savings throughout the life of the treated components
Author
FRICTION STIR WELDING; MECHANICAL PROPERTIES; CRACK INITIATION; FAULT TOLERANCE; SERVICE LIFE; LASERS
20090033737 NASA Langley Research Center, Hampton, VA, United States
Investigation of Helicopter Longeron Cracks
Newman, John A.; Baughman, James; Wallace, Terryl A.; September 2009; In English; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 698259.02.07.07.03.02
Report No.(s): NASA/TP-2009-215791; L-19704; LF99-9060; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033737
Four cracked longerons, containing a total of eight cracks, were provided for study. Cracked regions were cut from the longerons. Load was applied to open the cracks, enabling crack surface examination. Examination revealed that crack propagation was driven by fatigue loading in all eight cases. Fatigue crack initiation appears to have occurred on the top edge of the longerons near geometric changes that affect component bending stiffness. Additionally, metallurgical analysis has revealed a local depletion in alloying elements in the crack initiation regions that may be a contributing factor. Fatigue crack propagation appeared to be initially driven by opening-mode loading, but at a crack length of approximately 0.5 inches (12.7 mm), there is evidence of mixed-mode crack loading. For the longest cracks studied, shear-mode displacements destroyed crack-surface features of interest over significant portions of the crack surfaces.
Author
CRACK INITIATION; LONGERONS; HELICOPTERS; SURFACE CRACKS; CRACK PROPAGATION; FATIGUE (MATERIALS)
20090033738 NASA Glenn Research Center, Cleveland, OH, United States
Active Fail-Safe Micro-Array Flow Control for Advanced Embedded Propulsion Systems
Anderson, Bernhard H.; Mace, James L.; Mani, Mori; August 2009; In English; 47th Aerospace Sciences Meeting, 5-8 Jan. 2009, Orlando, FL, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 984754.02.07.03.13.02
Report No.(s): NASA/TM-2009-215596; AIAA Paper 2009-0741; E-16887; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033738
The primary objective of this research effort was to develop and analytically demonstrate enhanced first generation active "fail-safe" hybrid flow-control techniques to simultaneously manage the boundary layer on the vehicle fore-body and to control the secondary flow generated within modern serpentine or embedded inlet S-duct configurations. The enhanced first-generation technique focused on both micro-vanes and micro-ramps highly-integrated with micro -jets to provide nonlinear augmentation for the "strength' or effectiveness of highly-integrated flow control systems. The study focused on the micro -jet mass flow ratio (Wjet/Waip) range from 0.10 to 0.30 percent and jet total pressure ratios (Pjet/Po) from 1.0 to 3.0. The engine bleed airflow range under study represents about a 10 fold decrease in micro -jet airflow than previously required. Therefore, by pre-conditioning, or injecting a very small amount of high-pressure jet flow into the vortex generated by the micro-vane and/or micro-ramp, active flow control is achieved and substantial augmentation of the controlling flow is realized.
Author
FLOW DISTRIBUTION; PROPULSION SYSTEM CONFIGURATIONS; AERODYNAMIC CONFIGURATIONS; SYSTEMS INTEGRATION; BOUNDARY LAYERS; FAIL-SAFE SYSTEMS; JET FLOW; MASS FLOW
20090033743 NASA Langley Research Center, Hampton, VA, United States
Shuttle Orbiter-like Cargo Carrier on Crew Launch Vehicle
Martinovic, Zoran; September 2009; In English; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 304029.01.04.02.02
Report No.(s): NASA/TM-2009-215793; L-19711; LF99-9125; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033743
The following document summarizes the results of a conceptual design study for which the goal was to investigate the possibility of using a crew launch vehicle to deliver the remaining International Space Station elements should the Space Shuttle orbiter not be available to complete that task. Conceptual designs and structural weight estimates for two designs are presented. A previously developed systematic approach that was based on finite-element analysis and structural sizing was used to estimate growth of structural weight from analytical to "as built" conditions.
Author
FINITE ELEMENT METHOD; LAUNCH VEHICLES; INTERNATIONAL SPACE STATION; SPACE SHUTTLE ORBITERS; SPACECREWS; CARGO
20090033744 NASA Glenn Research Center, Cleveland, OH, United States
A Very Large Eddy Simulation of the Nonreacting Flow in a Single-Element Lean Direct Injection Combustor Using PRNS with a Nonlinear Subscale Model
Shih, Tsan-Hsing; Liu, Nan-Suey; August 2009; In English; Original contains color illustrations
Contract(s)/Grant(s): WBS 561581.02.08.03.16.02
Report No.(s): NASA/TM-2009-215644; E-16956; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033744
Very large eddy simulation (VLES) of the nonreacting turbulent flow in a single-element lean direct injection (LDI) combustor has been successfully performed via the approach known as the partially resolved numerical simulation (PRNS/VLES) using a nonlinear subscale model. The grid is the same as the one used in a previous RANS simulation, which was considered as too coarse for a traditional LES simulation. In this study, we first carry out a steady RANS simulation to provide the initial flow field for the subsequent PRNS/VLES simulation. We have also carried out an unsteady RANS (URANS) simulation for the purpose of comparing its results with that of the PRNS/VLES simulation. In addition, these calculated results are compared with the experimental data. The present effort has demonstrated that the PRNS/VLES approach, while using a RANS type of grid, is able to reveal the dynamically important, unsteady large-scale turbulent structures occurring in the flow field of a single-element LDI combustor. The interactions of these coherent structures play a critical role in the dispersion of the fuel, hence, the mixing between the fuel and the oxidizer in a combustor.
Author
LARGE EDDY SIMULATION; TURBULENT FLOW; COMPUTATIONAL FLUID DYNAMICS; FLOW DISTRIBUTION; INJECTION
20090033745 NASA Glenn Research Center, Cleveland, OH, United States
The Effects of Hot Corrosion Pits on the Fatigue Resistance of a Disk Superalloy
Gabb, Timothy P.; Telesman, Jack; Hazel, Brian; Mourer, David P.; August 2009; In English; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 698259.02.07.03.04.02
Report No.(s): NASA/TM-2009-215629; E-16940; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033745
The effects of hot corrosion pits on low cycle fatigue life and failure modes of the disk superalloy ME3 were investigated. Low cycle fatigue specimens were subjected to hot corrosion exposures producing pits, then tested at low and high temperatures. Fatigue lives and failure initiation points were compared to those of specimens without corrosion pits. Several tests were interrupted to estimate the fraction of fatigue life that fatigue cracks initiated at pits. Corrosion pits significantly reduced fatigue life by 60 to 98 percent. Fatigue cracks initiated at a very small fraction of life for high temperature tests, but initiated at higher fractions in tests at low temperature. Critical pit sizes required to promote fatigue cracking were estimated, based on measurements of pits initiating cracks on fracture surfaces.
Author
HEAT RESISTANT ALLOYS; HOT CORROSION; FATIGUE (MATERIALS); FAILURE MODES; SURFACE CRACKS; HIGH TEMPERATURE TESTS; FRACTURE STRENGTH
20090033749 NASA Glenn Research Center, Cleveland, OH, United States
Compressor Study to Meet Large Civil Tilt Rotor Engine Requirements
Veres, Joseph P.; August 2009; In English; 65th Annual Forum and Technology Display, 27-29 May 2009, Grapevine, TX, United States; Original contains black and white illustrations
Contract(s)/Grant(s): WBS 877868.02.07.03.01.02.02
Report No.(s): NASA/TM-2009-215641; E-16952; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033749
A vehicle concept study has been made to meet the requirements of the Large Civil Tilt Rotorcraft vehicle mission. A vehicle concept was determined, and a notional turboshaft engine system study was conducted. The engine study defined requirements for the major engine components, including the compressor. The compressor design-point goal was to deliver a pressure ratio of 31:1 at an inlet weight flow of 28.4 lbm/sec. To perform a conceptual design of two potential compressor configurations to meet the design requirement, a mean-line compressor flow analysis and design code were used. The first configuration is an eight-stage axial compressor. Some challenges of the all-axial compressor are the small blade spans of the rear-block stages being 0.28 in., resulting in the last-stage blade tip clearance-to-span ratio of 2.4 percent. The second configuration is a seven-stage axial compressor, with a centrifugal stage having a 0.28-in. impeller-exit blade span. The compressors conceptual designs helped estimate the flow path dimensions, rotor leading and trailing edge blade angles, flow conditions, and velocity triangles for each stage.
Author
COMPRESSORS; TURBOCOMPRESSORS; TILT ROTOR AIRCRAFT; LEADING EDGES; ROTARY WING AIRCRAFT; ENGINE DESIGN; FLOW VELOCITY; CENTRIFUGAL FORCE; TRAILING EDGES
20090033760 NASA Glenn Research Center, Cleveland, OH, United States
Effects of Thermal Exposure on the Optical Properties of LORD Aeroglaze A276
Ellis, David L.; Jaworske, Donald A.; August 2009; In English; Original contains color illustrations
Contract(s)/Grant(s): WBS 463169.04.03.05.01
Report No.(s): NASA/TM-2009-215652; E-16965; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033760
A lunar outpost will require electrical energy. One potential source is fission surface power where heat from a reactor is converted into electricity utilizing an energy conversion system, and waste heat will need to be rejected from the system. The Second Generation Radiator Demonstration Unit is a technology demonstration unit leading towards operational radiators. To approximate the infrared emittance of the lunar outpost radiators, a low-cost coating compatible with the test conditions was sought. LORD Aeroglaze A276 has a similar emittance, but its performance in air and vacuum at the desired operating temperatures was unknown. This study determined that the emittance remained above 0.86 for all conditions tested and that LORD Aeroglaze A276 is a suitable surrogate coating for the Second Generation Radiator Demonstration Unit.
Author
COATING; EMITTANCE; LUNAR BASES; ENERGY CONVERSION; OPERATING TEMPERATURE; OPTICAL PROPERTIES; INFRARED RADIATION; ELECTRICITY
20090033766 NASA Glenn Research Center, Cleveland, OH, United States
The NASA In-Space Propulsion Technology Project, Products, and Mission Applicability
Anderson, David J.; Pencil, Eric; Liou, Larry; Dankanich, John; Munk, Michelle M.; Kremic, Tibor; August 2009; In English; 2009 Aerospace Conference, 7-14 Mar. 2009, Big Sky, MT, United States; Original contains color illustrations
Contract(s)/Grant(s): WBS 346620.01.03.01
Report No.(s): NASA/TM-2009-215649; Paper no. 1176; E-169649; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033766
The In-Space Propulsion Technology (ISPT) Project, funded by NASA s Science Mission Directorate (SMD), is continuing to invest in propulsion technologies that will enable or enhance NASA robotic science missions. This overview provides development status, near-term mission benefits, applicability, and availability of in-space propulsion technologies in the areas of aerocapture, electric propulsion, advanced chemical thrusters, and systems analysis tools. Aerocapture investments improved: guidance, navigation, and control models of blunt-body rigid aeroshells; atmospheric models for Earth, Titan, Mars, and Venus; and models for aerothermal effects. Investments in electric propulsion technologies focused on completing NASA s Evolutionary Xenon Thruster (NEXT) ion propulsion system, a 0.6 to 7 kW throttle-able gridded ion system. The project is also concluding its High Voltage Hall Accelerator (HiVHAC) mid-term product specifically designed for a low-cost electric propulsion option. The primary chemical propulsion investment is on the high-temperature Advanced Material Bipropellant Rocket (AMBR) engine providing higher performance for lower cost. The project is also delivering products to assist technology infusion and quantify mission applicability and benefits through mission analysis and tools. In-space propulsion technologies are applicable, and potentially enabling for flagship destinations currently under evaluation, as well as having broad applicability to future Discovery and New Frontiers mission solicitations.
Author
ELECTRIC PROPULSION; ION PROPULSION; CHEMICAL PROPULSION; AEROCAPTURE; PROPULSION SYSTEM PERFORMANCE; HALL ACCELERATORS; ION ENGINES; LIQUID ROCKET PROPELLANTS; PROPULSION SYSTEM CONFIGURATIONS
20090033769 NASA Glenn Research Center, Cleveland, OH, United States
NASA PS400: A New Temperature Solid Lubricant Coating for High Temperature Wear Applications
DellaCorte, C.; Edmonds, B. J.; August 2009; In English; Original contains black and white illustrations
Contract(s)/Grant(s): WBS 877868.02.07.03.01.01.14
Report No.(s): NASA/TM-2009-215678; E-17044; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033769
A new solid lubricant coating, NASA PS400, has been developed for high temperature tribological applications. This plasma sprayed coating is a variant of the patented PS304 coating and has been formulated to provide higher density, smoother surface finish and better dimensional stability than PS304. PS400 is comprised of a nickel-molybdenum binder that provides strength, creep resistance and extreme oxidative and dimensional stability. Chromium oxide, silver and barium-calcium fluoride eutectic are added to the binder to form PS400.Tribological properties were evaluated with a pin-on-disk test rig in sliding contact to 650 C. Coating material samples were exposed to air, argon and vacuum at 760 C followed by cross section microscopic analysis to assess microstructure stability. Oil-Free microturbine engine hot section foil bearing tests were undertaken to assess PS400 s suitability for hot foil gas bearing applications. The preliminary results indicate that PS400 exhibits tribological characteristics comparable to the PS304 coating but with enhanced creep resistance and dimensional stability suitable for demanding, dynamic applications.
Author
SOLID LUBRICANTS; HIGH TEMPERATURE; FOIL BEARINGS; FRICTION; TRIBOLOGY; CHROMIUM OXIDES; MOLYBDENUM; NICKEL
20090033772 NASA Langley Research Center, Hampton, VA, United States
Position Paper External Tank Thermal Protection System (TPS) Manually Sprayed fly-as-is Foam Certification
Stadler, John H.; August 2009; In English; Original contains black and white illustrations
Contract(s)/Grant(s): WBS 869021.01.07.01.01
Report No.(s): NASA/TM-2009-215917; NESC-PB-04-10; L-19752; LF99-9332; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033772
During manufacture of the existing External Tanks (ETs), the Thermal Protection System (TPS) foam manual spray application processes lacked the enhanced controls/procedures to ensure that defects produced were less than the critical size. Therefore the only remaining option to certify the "fly-as-is" foam is to verify ET120 tank hardware meets the new foam debris requirements. The ET project has undertaken a significant effort studying the existing "fly-as-is" TPS foam. This paper contains the findings of the study.
Author
THERMAL PROTECTION; EXTERNAL TANKS; FOAMS; CERTIFICATION; DEBRIS; DEFECTS
20090033773 Wyle Labs., Inc., Houston, TX, United States
Infectious Considerations in Space Flight
Haddon, Robert; September 15, 2009; In English; Cleveland Clinic Foundation, 15 Sep. 2009, Cleveland, OH, United States; Original contains color and black and white illustrations
Report No.(s): JSC-CN-18838; Copyright; Avail.: CASI: A05, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033773
Slightly more than 500 people have flown in space, most of them for short periods of time. The total number of person years in space is small. Given this fact, and given rigorous astronaut screening, it is not surprising that the accumulated infectious disease experience in space is also small, and mostly, theoretical. As the human space presence expands, we may expect mission length, total accumulated person years and the environmental complexity to increase. Add to the mix both changes in human immunity and microbial virulence, and it becomes realistic to consider infectious scenarios and the means to mitigate them. This lecture will cover the inhabited space environment from the perspective of host-microbe interactions, current relevant research, and the current countermeasures used. Future challenges will be discussed and there will be opportunity to ask questions about Space Operations. The audience is encouraged to think about what medical tools you would choose to have in different types of mission, what you would be willing to leave behind, and how you would compensate for the necessary trade offs in mission design.
Derived from text
AEROSPACE ENVIRONMENTS; INFECTIOUS DISEASES; MANNED SPACE FLIGHT; IMMUNE SYSTEMS; MICROBIOLOGY; AEROSPACE MEDICINE
20090033774 NASA Langley Research Center, Hampton, VA, United States
Laura Users Manual: 5.1-41601
Mazaheri, Alireza; Gnoffo, Peter A.; Johnston, Christopher O.; Kleb, Bil; August 2009; In English
Contract(s)/Grant(s): WBS 37781606030308
Report No.(s): NASA/TM-2009-215783; L-19726; LF99-9183; Copyright; Avail.: CASI: A04, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033774
This users manual provides in-depth information concerning installation and execution of LAURA, version 5. LAURA is a structured, multi-block, computational aerothermodynamic simulation code. Version 5 represents a major refactoring of the original Fortran 77 LAURA code toward a modular structure afforded by Fortran 95. The refactoring improved usability and maintainability by eliminating the requirement for problem-dependent re-compilations, providing more intuitive distribution of functionality, and simplifying interfaces required for multiphysics coupling. As a result, LAURA now shares gas-physics modules, MPI modules, and other low-level modules with the FUN3D unstructured-grid code. In addition to internal refactoring, several new features and capabilities have been added, e.g., a GNU-standard installation process, parallel load balancing, automatic trajectory point sequencing, free-energy minimization, and coupled ablation and flowfield radiation.
Author
AEROTHERMODYNAMICS; ABLATION; APPLICATIONS PROGRAMS (COMPUTERS); COMPUTER PROGRAMS; COMPUTERIZED SIMULATION; UNSTRUCTURED GRIDS (MATHEMATICS); MAINTAINABILITY
20090033783 NASA Langley Research Center, Hampton, VA, United States
A Simple Sensor Model for THUNDER Actuators
Campbell, Joel F.; Bryant, Robert G.; September 2009; In English; Original contains color illustrations
Contract(s)/Grant(s): WBS 129985.05.07.98.42.02
Report No.(s): LF99-7603; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033783
A quasi-static (low frequency) model is developed for THUNDER actuators configured as displacement sensors based on a simple Raleigh-Ritz technique. This model is used to calculate charge as a function of displacement. Using this and the calculated capacitance, voltage vs. displacement and voltage vs. electrical load curves are generated and compared with measurements. It is shown this model gives acceptable results and is useful for determining rough estimates of sensor output for various loads, laminate configurations and thicknesses.
Author
ACTUATORS; CAPACITANCE; ELECTRIC POTENTIAL; STATIC MODELS; ESTIMATES
20090033784 Georgia Tech Research Inst., Atlanta, GA, United States
Unsteady Extinction of Opposed Jet Ethylene/Methane HIFiRE Surrogate Fuel Mixtures vs Air
Vaden, Sarah N.; Debes, Rachel L.; Lash, E. Lara; Burk, Rachel S.; Boyd, C. Merritt; Wilson, Lloyd G.; Pellett, Gerald L.; August 03, 2009; In English; 45th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 3 - 5 Aug. 2009, Denver, CO, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 736466.11.01.07.43.06
Report No.(s): AIAA Paper 2009-4879; LF99-8201; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033784
A unique idealized study of the subject fuel vs. air systems was conducted using an Oscillatory-input Opposed Jet Burner (OOJB) system and a newly refined analysis. Extensive dynamic-extinction measurements were obtained on unanchored (free-floating) laminar Counter Flow Diffusion Flames (CFDFs) at 1-atm, stabilized by steady input velocities (e.g., U(sub air)) and perturbed by superimposed in-phase sinusoidal velocity inputs at fuel and air nozzle exits. Ethylene (C2H4) and methane (CH4), and intermediate 64/36 and 15/85 molar percent mixtures were studied. The latter gaseous surrogates were chosen earlier to mimic ignition and respective steady Flame Strengths (FS = U(sub air)) of vaporized and cracked, and un-cracked, JP-7 "like" kerosene for a Hypersonic International Flight Research Experimentation (HIFiRE) scramjet. For steady idealized flameholding, the 100% C2H4 flame is respectively approx. 1.3 and approx.2.7 times stronger than a 64/36 mix and CH4; but is still 12.0 times weaker than a 100% H2-air flame. Limited Hot-Wire (HW) measurements of velocity oscillations at convergent-nozzle exits, and more extensive Probe Microphone (PM) measurements of acoustic pressures, were used to normalize Dynamic FSs, which decayed linearly with pk/pk U(sub air) (velocity magnitude, HW), and also pk/pk P (pressure magnitude, PM). Thus Dynamic Flame Weakening (DFW) is defined as % decrease in FS per Pascal of pk/pk P oscillation, namely, DFW = -100 d(U(sub air)/U(sub air),0Hz)/d(pkpk P). Key findings are: (1) Ethylene flames are uniquely strong and resilient to extinction by oscillating inflows below 150 Hz; (2) Methane flames are uniquely weak; (3) Ethylene / methane surrogate flames are disproportionately strong with respect to ethylene content; and (4) Flame weakening is consistent with limited published results on forced unsteady CFDFs. Thus from 0 to approx. 10 Hz and slightly higher, lagging diffusive responses of key species led to progressive phase lags (relative to inputs) in the oscillating flames, and caused maximum weakening. At 20 to 150 Hz, diffusion-rate-limited effects diminished, causing flames to "regain strengnth," and eventually become completely insensitive beyond 300 Hz. Detailed mechanistic understanding is needed. Overall, ethylene flames are remarkably resilient to dynamic extinction by oscillating inflows. They are the strongest, with the notable exception of H2. For HIFiRE tests, the 64%/36% surrogate disproportionally retains the high dynamic FS of ethylene, so the potential for loss of scramjet flameholding (flameout) due to low frequency oscillations is significantly mitigated.
Author
CONVERGENT NOZZLES; DIFFUSION FLAMES; JP-7 JET FUEL; METHANE; ETHYLENE; LAMINAR FLOW; FLAMEOUT; SUPERSONIC COMBUSTION RAMJET ENGINES
20090033792 NASA Langley Research Center, Hampton, VA, United States
Simulation of the Thermographic Response of Near Surface Flaws in Reinforced Carbon-Carbon Panels
Winfree, William P.; Howell, Patricia A.; Burke, Eric R.; July 26, 2009; In English; QNDE 2009 - Quantitative Nondestructive Evaluation Conference, 26-31 Jul. 2009, Kingston, RI, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 736466.08.01.07.43
Report No.(s): LF99-8707; Copyright; Avail.: CASI: A02, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033792
Thermographic inspection is a viable technique for detecting in-service damage in reinforced carbon-carbon (RCC) composites that are used for thermal protection in the leading edge of the shuttle orbiter. A thermographic technique for detection of near surface flaws in RCC composite structures is presented. A finite element model of the heat diffusion in structures with expected flaw configurations is in good agreement with the experimental measurements.
Author
THERMOGRAPHY; INSPECTION; CARBON-CARBON COMPOSITES; DAMAGE; LEADING EDGES; THERMAL PROTECTION
20090033794 NASA Langley Research Center, Hampton, VA, United States
The Use of Meteorlogical Data to Improve Contrail Detection in Thermal Imagery over Ireland.
Whelan, Gillian M.; Cawkwell, Fiona; Mannstein, Hermann; Minnis, Patrick; September 08, 2009; In English; RSPSoc Annual Conference, 8-11 Sept. 2009, Leicester, United Kingdom; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 967701.02.02.01.13
Report No.(s): LF99-8777; Copyright; Avail.: CASI: A02, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033794
Aircraft induced contrails have been found to have a net warming influence on the climate system, with strong regional dependence. Persistent linear contrails are detectable in 1 Km thermal imagery and, using an automated Contrail Detection Algorithm (CDA), can be identified on the basis of their different properties at the 11 and 12 m w av.el enTgthshe algorithm s ability to distinguish contrails from other linear features depends on the sensitivity of its tuning parameters. In order to keep the number of false identifications low, the algorithm imposes strict limits on contrail size, linearity and intensity. This paper investigates whether including additional information (i.e. meteorological data) within the CDA may allow for these criteria to be less rigorous, thus increasing the contrail-detection rate, without increasing the false alarm rate.
Author
CONTRAILS; METEOROLOGICAL PARAMETERS; LINEARITY; DETECTION; THERMAL MAPPING
20090033796 NASA Langley Research Center, Hampton, VA, United States
Lightning Pin Injection Testing on MOSFETS
Ely, Jay J.; Nguyen, Truong X.; Szatkowski, George N.; Koppen, Sandra V.; Mielnik, John J.; Vaughan, Roger K.; Wysocki, Philip F.; Celaya, Jose R.; Saha, Sankalita; September 2009; In English; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 645846.02.07.07.12.02
Report No.(s): NASA/TM-2009-215794; L-19713; LF99-9139; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033796
Lightning transients were pin-injected into metal-oxide-semiconductor field-effect transistors (MOSFETs) to induce fault modes. This report documents the test process and results, and provides a basis for subsequent lightning tests. MOSFETs may be present in DC-DC power supplies and electromechanical actuator circuits that may be used on board aircraft. Results show that unprotected MOSFET Gates are susceptible to failure, even when installed in systems in well-shielded and partial-shielded locations. MOSFET Drains and Sources are significantly less susceptible. Device impedance decreased (current increased) after every failure. Such a failure mode may lead to cascading failures, as the damaged MOSFET may allow excessive current to flow through other circuitry. Preliminary assessments on a MOSFET subjected to 20-stroke pin-injection testing demonstrate that Breakdown Voltage, Leakage Current and Threshold Voltage characteristics show damage, while the device continues to meet manufacturer performance specifications. The purpose of this research is to develop validated tools, technologies, and techniques for automated detection, diagnosis and prognosis that enable mitigation of adverse events during flight, such as from lightning transients; and to understand the interplay between lightning-induced surges and aging (i.e. humidity, vibration thermal stress, etc.) on component degradation.
Author
DEGRADATION; METAL OXIDE SEMICONDUCTORS; FIELD EFFECT TRANSISTORS; LIGHTNING; THERMAL STRESSES; THRESHOLD VOLTAGE; DIRECT CURRENT; ELECTROMECHANICAL DEVICES
20090033804 Binghamton Univ., Binghamton, NY, United States
Motion Cueing Algorithm Modification for Improved Turbulence Simulation
Ercole, Anthony V.; Cardullo, Frank M.; Zaychik, Kirill; Kelly, Lon C.; Houck, Jacob; August 10, 2009; In English; AIAA Modeling and Simulation Technologies Conference, 10-13 Aug. 2009, Chicago, IL, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 160961.01.01.01
Report No.(s): AIAA Paper 2009-6247; LF99-9191; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033804
Atmospheric turbulence cueing produced by flight simulator motion systems has been less than satisfactory because the turbulence profiles have been attenuated by the motion cueing algorithms. Cardullo and Ellor initially addressed this problem by directly porting the turbulence model output to the motion system. Reid and Robinson addressed the problem by employing a parallel aircraft model, which is only stimulated by the turbulence inputs and adding a filter specially designed to pass the higher turbulence frequencies. There have been advances in motion cueing algorithm development at the Man-Machine Systems Laboratory, at SUNY Binghamton. In particular, the system used to generate turbulence cues has been studied. The Reid approach, implemented by Telban and Cardullo, was employed to augment the optimal motion cueing algorithm installed at the NASA LaRC Simulation Laboratory, driving the Visual Motion Simulator. In this implementation, the output of the primary flight channel was added to the output of the turbulence channel and then sent through a non-linear cueing filter. The cueing filter is an adaptive filter; therefore, it is not desirable for the output of the turbulence channel to be augmented by this type of filter. The likelihood of the signal becoming divergent was also an issue in this design. After testing on-site it became apparent that the architecture of the turbulence algorithm was generating unacceptable cues. As mentioned above, this cueing algorithm comprised a filter that was designed to operate at low bandwidth. Therefore, the turbulence was also filtered, augmenting the cues generated by the model. If any filtering is to be done to the turbulence, it will utilize a filter with a much higher bandwidth, above the frequencies produced by the aircraft response to turbulence. The authors have developed an implementation wherein only the signal from the primary flight channel passes through the nonlinear cueing filter. This paper discusses three new algorithms. Testing shows that the new methods provide the pilot with a more realistic sensation of turbulence; the cues are not attenuated by algorithm. Results of offline testing show the credibility of the models. Offline test verification was based primarily on the evaluation of the power spectral density of the outputs and the time response.
Author
ALGORITHMS; FLIGHT SIMULATORS; MOTION SIMULATORS; TURBULENCE MODELS; ATMOSPHERIC TURBULENCE
20090033805 NASA Langley Research Center, Hampton, VA, United States
Effectiveness of Shield Termination Techniques Tested with TEM Cell and Bulk Current Injection
Bradley, Arthur T.; Hare, Richard J.; August 17, 2009; In English; IEEE EMC 2009 Symposium, 17-21 Aug. 2009, Austin, TX, United States; Original contains color illustrations
Contract(s)/Grant(s): WBS 736466.08.01.07.01
Report No.(s): LF99-9338; No Copyright; Avail.: CASI: A02, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033805
This paper presents experimental results of the effectiveness of various shield termination techniques. Each termination technique is evaluated by two independent noise injection methods; transverse electromagnetic (TEM) cell operated from 3 MHz 400 MHz, and bulk current injection (BCI) operated from 50 kHz 400 MHz. Both single carrier and broadband injection tests were investigated. Recommendations as to how to achieve the best shield transfer impedance (i.e. reduced coupled noise) are made based on the empirical data. Finally, the noise injection techniques themselves are indirectly evaluated by comparing the results obtained from the TEM Cell to those from BCI.
Author
TRANSVERSE MOMENTUM; ELECTRIC CURRENT; CARRIER INJECTION; ELECTRICAL ENGINEERING; ELECTROMAGNETISM
20090033807 NASA Langley Research Center, Hampton, VA, United States
Development of the One-Sided Nonlinear Adaptive Doppler Shift Estimation
Beyon, Jeffrey Y.; Koch, Grady J.; Singh, Upendra N.; Kavaya, Michael J.; Serror, Judith A.; August 31, 2009; In English; SPIE Europe Remote Sensing, 31 Aug. - 2 Sep. 2009, Berlin, Germany; Original contains color and black and white illustrations
Report No.(s): 7479-21; LF99-9253; Copyright; Avail.: CASI: A02, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033807
The new development of a one-sided nonlinear adaptive shift estimation technique (NADSET) is introduced. The background of the algorithm and a brief overview of NADSET are presented. The new technique is applied to the wind parameter estimates from a 2-micron wavelength coherent Doppler lidar system called VALIDAR located in NASA Langley Research Center in Virginia. The new technique enhances wind parameters such as Doppler shift and power estimates in low Signal-To-Noise-Ratio (SNR) regimes using the estimates in high SNR regimes as the algorithm scans the range bins from low to high altitude. The original NADSET utilizes the statistics in both the lower and the higher range bins to refine the wind parameter estimates in between. The results of the two different approaches of NADSET are compared.
Author
DOPPLER EFFECT; DOPPLER RADAR; SIGNAL TO NOISE RATIOS; WIND MEASUREMENT; PARAMETER IDENTIFICATION; OPTICAL RADAR; ESTIMATES
Additions to the NASA Aeronautics and Space Database as of 10/08/2009
20090033820 Research Inst. for Advanced Computer Science, Moffett Field, CA, United States
Communication Optimizations for a Wireless Distributed Prognostic Framework
Saha, Sankalita; Saha, Bhaskar; Goebel, Kai; March 07, 2009; In English; 2009 IEEE Aerospace Conference, 7-14 Mar. 2009, Big Sky, MT, United States; Original contains color illustrations
Contract(s)/Grant(s): WBS 645846.02.07.01.01
Report No.(s): ARC-E-DAA-TN-246; Copyright; Avail.: CASI: A02, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033820
Distributed architecture for prognostics is an essential step in prognostic research in order to enable feasible real-time system health management. Communication overhead is an important design problem for such systems. In this paper we focus on communication issues faced in the distributed implementation of an important class of algorithms for prognostics - particle filters. In spite of being computation and memory intensive, particle filters lend well to distributed implementation except for one significant step - resampling. We propose new resampling scheme called parameterized resampling that attempts to reduce communication between collaborating nodes in a distributed wireless sensor network. Analysis and comparison with relevant resampling schemes is also presented. A battery health management system is used as a target application. A new resampling scheme for distributed implementation of particle filters has been discussed in this paper. Analysis and comparison of this new scheme with existing resampling schemes in the context for minimizing communication overhead have also been discussed. Our proposed new resampling scheme performs significantly better compared to other schemes by attempting to reduce both the communication message length as well as number total communication messages exchanged while not compromising prediction accuracy and precision. Future work will explore the effects of the new resampling scheme in the overall computational performance of the whole system as well as full implementation of the new schemes on the Sun SPOT devices. Exploring different network architectures for efficient communication is an importance future research direction as well.
Author
ELECTRIC BATTERIES; DESIGN ANALYSIS; REAL TIME OPERATION; MANAGEMENT SYSTEMS; OPTIMIZATION; PRECISION
20090033821 Research Inst. for Advanced Computer Science, Moffett Field, CA, United States
Evaluating Algorithm Performance Metrics Tailored for Prognostics
Saxena, Abhinav; Celaya, Jose; Saha, Bhaskar; Saha, Sankalita; Goebel, Kai; March 07, 2009; In English; 2009 IEEE Aerospace Conference, 7 - 14 Mar. 2009, Big Sky, MT, United States; Original contains color illustrations
Contract(s)/Grant(s): WBS 645846.02.07.01.01
Report No.(s): ARC-E-DAA-TN-245; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033821
Prognostics has taken a center stage in Condition Based Maintenance (CBM) where it is desired to estimate Remaining Useful Life (RUL) of the system so that remedial measures may be taken in advance to avoid catastrophic events or unwanted downtimes. Validation of such predictions is an important but difficult proposition and a lack of appropriate evaluation methods renders prognostics meaningless. Evaluation methods currently used in the research community are not standardized and in many cases do not sufficiently assess key performance aspects expected out of a prognostics algorithm. In this paper we introduce several new evaluation metrics tailored for prognostics and show that they can effectively evaluate various algorithms as compared to other conventional metrics. Specifically four algorithms namely; Relevance Vector Machine (RVM), Gaussian Process Regression (GPR), Artificial Neural Network (ANN), and Polynomial Regression (PR) are compared. These algorithms vary in complexity and their ability to manage uncertainty around predicted estimates. Results show that the new metrics rank these algorithms in different manner and depending on the requirements and constraints suitable metrics may be chosen. Beyond these results, these metrics offer ideas about how metrics suitable to prognostics may be designed so that the evaluation procedure can be standardized. 1
Author
NEURAL NETS; ESTIMATES; MAINTENANCE; STANDARDIZATION; ALGORITHMS
20090033822 Research Inst. for Advanced Computer Science, Moffett Field, CA, United States
Prognostics for Electronics Components of Avionics Systems
Celaya, Jose R.; Saha, Bhaskar; Wysocki, Philip F.; Goebel, Kai F.; March 07, 2009; In English; 2009 IEEE Aerospace Conference, 7-14 Mar. 2009, Big Sky, MT, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 645846.02.07.01.01
Report No.(s): ARC-E-DAA-TN-244; Copyright; Avail.: CASI: A02, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033822
Electronics components have and increasingly critical role in avionics systems and for the development of future aircraft systems. Prognostics of such components is becoming a very important research filed as a result of the need to provide aircraft systems with system level health management. This paper reports on a prognostics application for electronics components of avionics systems, in particular, its application to the Isolated Gate Bipolar Transistor (IGBT). The remaining useful life prediction for the IGBT is based on the particle filter framework, leveraging data from an accelerated aging tests on IGBTs. The accelerated aging test provided thermal-electrical overstress by applying thermal cycling to the device. In-situ state monitoring, including measurements of the steady-state voltages and currents, electrical transients, and thermal transients are recorded and used as potential precursors of failure.
Author
AVIONICS; LIFE (DURABILITY); THERMAL CYCLING TESTS; ACCELERATED LIFE TESTS; BIPOLAR TRANSISTORS; ELECTRIC POTENTIAL; SYSTEMS ENGINEERING
Additions to the NASA Aeronautics and Space Database as of 10/09/2009
20090033934 NASA Goddard Space Flight Center, Greenbelt, MD, United States
The Astrophysics Science Division Annual Report 2008
Oegerle, William; Reddy, Francis; Tyler, Pat; March 2009; In English; Original contains color and black and white illustrations
Contract(s)/Grant(s): NG07EK67C
Report No.(s): NASA/TM-2009-214182; 200902507; Copyright; Avail.: CASI: A05, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033934
The Astrophysics Science Division (ASD) at Goddard Space Flight Center (GSFC) is one of the largest and most diverse astrophysical organizations in the world, with activities spanning a broad range of topics in theory, observation, and mission and technology development. Scientific research is carried out over the entire electromagnetic spectrum from gamma rays to radio wavelengths as well as particle physics and gravitational radiation. Members of ASD also provide the scientific operations for three orbiting astrophysics missions WMAP, RXTE, and Swift, as well as the Science Support Center for the Fermi Gamma-ray Space Telescope. A number of key technologies for future missions are also under development in the Division, including X-ray mirrors, and new detectors operating at gamma-ray, X-ray, ultraviolet, infrared, and radio wavelengths. This report includes the Division's activities during 2008.
Author
ASTROPHYSICS; GAMMA RAY TELESCOPES; X RAY TIMING EXPLORER; COSMOLOGY; AEROSPACE SCIENCES
20090033937 NASA Dryden Flight Research Center, Edwards, CA, United States
IRAC Full-Scale Flight Testbed Capabilities
Lee, James A.; Pahle, Joseph; Cogan, Bruce R.; Hanson, Curtis E.; Bosworth, John T.; August 09, 2009; In English; NASA IRAC RFI Response Workshop, 9 Aug. 2009, Chicago, IL, United States; Original contains color and black and white illustrations
Report No.(s): DFRC-1044; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033937
Overview: Provide validation of adaptive control law concepts through full scale flight evaluation in a representative avionics architecture. Develop an understanding of aircraft dynamics of current vehicles in damaged and upset conditions Real-world conditions include: a) Turbulence, sensor noise, feedback biases; and b) Coupling between pilot and adaptive system. Simulated damage includes 1) "B" matrix (surface) failures; and 2) "A" matrix failures. Evaluate robustness of control systems to anticipated and unanticipated failures.
Author
ADAPTIVE CONTROL; FLIGHT TESTS; ROBUSTNESS (MATHEMATICS); AVIONICS; CONTROL THEORY
20090033997 NASA Goddard Space Flight Center, Greenbelt, MD, United States
International VLBI Service for Geodesy and Astrometry 2008 Annual Report
Behrend, Dirk; Baver, Karen D.; August 2009; In English; Original contains color and black and white illustrations
Report No.(s): NASA/TP-2009-214183; Rept-200902253; Copyright; Avail.: CASI: A18, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033997
This volume of reports is the 2008 Annual Report of the International VLBI Service for Geodesy and Astrometry (IVS). The individual reports were contributed by VLBI groups in the international geodetic and astrometric community who constitute the components of IVS. The 2008 Annual Report documents the work of these IVS components over the period January 1, 2008 through December 31, 2008. The reports document changes, activities, and progress of the IVS. The entire contents of this Annual Report also appear on the IVS Web site at http://ivscc.gsfc.nasa.gov/publications/ar2008.
Author
GEODESY; ASTROMETRY; VERY LONG BASE INTERFEROMETRY; GEOPHYSICS; RADIO ASTRONOMY; GEODYNAMICS; EARTH ORIENTATION
20090033998 Norwegian Defence Research Establishment, Norway
FFI Technology Development Center - Software Development
Andersen, Per Helge; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 31; In English
Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033998
FFI's contribution to the IVS as a Technology Development Center focuses primarily on the development and validation of the GEOSAT software for a combined analysis at the observation level of data from VLBI, GPS and SLR. This report shortly summarises the latest improvements of the GEOSAT software. FFI is currently an Analysis Center for IVS and ILRS, and a Technology Development Center for IVS
Author
VERY LONG BASE INTERFEROMETRY; COMPUTER PROGRAMS; SOFTWARE ENGINEERING; PROGRAM VERIFICATION (COMPUTERS); GLOBAL POSITIONING SYSTEM; GEOSAT SATELLITES; COMPUTER PROGRAMMING
20090033999 NASA Goddard Space Flight Center, Greenbelt, MD, United States
GSFC Technology Development Center Report
Himwich, Ed; Gipson, John; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 318-32; In English
Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090033999
This report summarizes the activities of the GSFC Technology Development Center (TDC) for 2008 and forecasts planned activities for 2009. The GSFC TDC develops station software including the Field System, scheduling software (SKED), hardware including tools for station timing and meteorology, scheduling algorithms, and operational procedures. It provides a pool of individuals to assist with station implementation, check-out, upgrades, and training. 1. Technology Center Activities The GSFC IVS Technology Development Center (TDC) develops hardware, software, algorithms, and operational procedures. It provides manpower for station visits for training and upgrades. Other technology development areas at GSFC are covered by other IVS components such as the GSFC Analysis Center. The current staff of the GSFC TDC consists of John Gipson and Ed Himwich, both employed by NVI, Inc. The remainder of this report covers the status of the main areas of development that are currently being pursued.
Author
SOFTWARE ENGINEERING; COMPUTER PROGRAMS; MANPOWER; EDUCATION; ALGORITHMS
20090034000 Natural Resources Canada, Ottawa, Ontario, Canada
Canadian VLBI Technology Development Center
Petrachenko, Bill; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 315-31; In English; Original contains color illustrations
Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034000
The Canadian VLBI Technology Development Center (TDC) is actively involved in theoretical studies to define recommendations for the VLBI2010 system. In addition, two development programs at the Dominion Radio Astrophysical Observatory (DRAO) are of potential interest to VLBI2010. Composite antennas that are light, stiff, and cost effective are being developed, and a state-of-the-art correlator is being developed for the EVLA.
Author
VERY LONG BASE INTERFEROMETRY; ASTROPHYSICS; OBSERVATORIES; GEODETIC SURVEYS; CORRELATORS; EARTH RESOURCES
20090034001 Onsala Space Observatory, Sweden
Onsala Space Observatory - IVS Network Station
Haas, Rudiger; Elgered, Gunnar; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 146-14; In English; Original contains black and white illustrations
Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034001
During 2008 the Onsala Space Observatory contributed as an IVS Network Station to 38 VLBI sessions organized by the IVS. Additionally, we performed 27 ultra-rapid dUT1-sessions together with partner telescopes in Japan and Finland. This report briefly summarizes the activities during the year 2008. In 2008 the observatory was involved in the five IVS series EUROPE, R1, T2, RDV, and RD08 plus the CONT08 campaign. In total, Onsala participated and acquired useful observations in 38 experiments, see Table 2. All experiments were recorded on Mark 5 modules. Most of the experiments whose data were correlated at the Bonn correlator were additionally recorded in parallel on the PCEVN computer that is daisy-chained to the Mark 5 computer. The observed data of these experiments were then transferred electronically using the Tsunami protocol, and no Mark 5 modules were actually sent to Bonn. Radio interference due to UMTS mobile telephone signals continued to be a disturbing factor for the S-band observations. Additionally, we suffered from problems with the telescope encoders.
Author
RADIO FREQUENCY INTERFERENCE; VERY LONG BASE INTERFEROMETRY; SUPERHIGH FREQUENCIES; CORRELATORS; OBSERVATORIES; TSUNAMI WAVES; ULTRAHIGH FREQUENCIES
20090034002 Observatoire de Paris, France
Paris Observatory (OPAR) Data Center
Barache, Christophe; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 236-23; In English; Original contains color illustrations
Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034002
This report summarizes the OPAR Data Center activities in 2008. Included is information about functions, architecture, status, future plans, and staff members of OPAR Data Center. The Paris Observatory (OPAR) has provided a Data Center for the International VLBI Service for Geodesy and Astrometry (IVS) since 1999. The OPAR as well as CDDIS and BKG is one of the three IVS Primary Data Centers. Their activities are done in close collaboration for the purposes of collecting files (data and analysis files), and making them available to the community as soon as they are submitted. The three data centers have a common protocol and each of them: has the same directory structure (with the same control file), has the same script, is able to receive all IVS files (auxiliary, database, products, documents), mirrors the other ones every three hours, gives free FTP access to the files.
Author
DATA ACQUISITION; VERY LONG BASE INTERFEROMETRY; DATA BASES; GEODESY; LIBRARIES; DIRECTORIES
20090034003 Naval Observatory, Washington, DC, United States
U.S. Naval Observatory VLBI Analysis Center
Boboltz, David A.; Fey, Alan L.; Bartlett, Jennifer L.; Dugan, Zachary; Kingham, Kerry A.; Hall, David M.; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 305-30; In English; Original contains black and white illustrations
Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034003
This report summarizes the activities of the VLBI Analysis Center at the United States Naval Observatory for calendar year 2008. Over the course of the year, Analysis Center personnel analyzed biweekly 24-hour experiments with designations IVS-R1 and IVS-R4 for use in-house and continued timely submission of IVS-R4 databases for distribution to the IVS. During the 2008 calendar year, the USNO Analysis Center produced two periodic global Terrestrial Reference Frame (TRF) solutions with designations usn2008a and usn2008b. Earth orientation parameters (EOP) based on these solutions, updated by the latest 24-hour (IVS-R1 and IVS-R4) experiments, were submitted to the IVS. Other activities in the 2008 calendar year included the continued submission of Sinex files based on new 24-hour experiments to the IVS. For the Celestial Reference Frame (CRF), Analysis Center personnel continued a program designed to increase the sky density of ICRF sources, especially in the Southern Hemisphere. Activities included scheduling, analyzing and submitting databases for IVS-CRF experiments, and the production of global CRF solutions designated crf2008a and crf2008b. In addition, Analysis Center personnel performed research into the next generation ICRF-2 and a future high-frequency reference frame based on the VLBA K/Q-band experiments. Activities planned for the 2009 calendar year include the continued production of EOP/TRF/CRF global solutions and continued research into future reference frames.
Author
VERY LONG BASE INTERFEROMETRY; CELESTIAL REFERENCE SYSTEMS; EARTH ORIENTATION; EXTREMELY HIGH FREQUENCIES; PLASMA HEATING; STRUCTURAL ANALYSIS; OBSERVATORIES; NAVY
20090034004 Naval Observatory, Washington, DC, United States
USNO Analysis Center for Source Structure Report
Fey, Alan L.; Boboltz, David A.; Ojha, Roopesh; Gaume, Ralph A.; Kingham, Kerry A.; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 309-31; In English; Original contains color illustrations
Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034004
This report summarizes the activities of the United States Naval Observatory Analysis Center for Source Structure for calendar year 2008. VLBA RDV experiments RDV67 and RDV69 were calibrated and imaged. Images from these two experiments, together with images from RDV14, RDV17, RDV19, and RDV22, were added to the USNO Radio Reference Frame Image Database. A Southern Hemisphere imaging and astrometry program for maintenance of the ICRF continued. Activities planned for the year 2009 include continued imaging of ICRF sources at standard and higher frequencies and continued analysis of source structure and its variation.
Author
VERY LONG BASELINE ARRAY (VLBA); CALIBRATING; RADIO FREQUENCY HEATING; IMAGING TECHNIQUES; ION CYCLOTRON RADIATION; ASTROMETRY; DATA BASES
20090034005 NASA Goddard Space Flight Center, Greenbelt, MD, United States
CORE Operation Center Report
Thomas, Cynthia C.; MacMillan, Daniel; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 195-19; In English
Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034005
This report gives a synopsis of the activities of the Continuous Observations of the Rotation of the Earth (CORE) Operation Center from January 2008 to report forecasts activities planned for 2009.
Author
EARTH ROTATION; EARTH ORIENTATION
20090034006 Onsala Space Observatory, Sweden
Onsala Space Observatory - IVS Analysis Center
Haas, Ruediger; Scherneck, Georg; Nilsson, Tobias; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 295-29; In English; Original contains color illustrations
Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034006
We briefly summarize the activities of the IVS Analysis Center at the Onsala Space Observatory during 2008 and give examples of results of ongoing work. 1. Introduction We concentrate on a number of research topics that are relevant for space geodesy and geosciences. These research topics are addressed in connection to data observed with geodetic VLBI and complementing techniques. Some topics are briefly presented in the following.
Author
VERY LONG BASE INTERFEROMETRY; OBSERVATORIES; GEOPHYSICS; GEODESY
20090034007 Italian Space Agency, Matera, Italy
Matera CGS VLBI Analysis Center
Lanotte, Roberto; Bianco, Giuseppe; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 253-25; In English
Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034007
This paper reports the VLBI data analysis activities at the Space Geodesy Center (CGS) at Matera from January 2008 through December 2008 and the contributions that the CGS intends to provide for the future as an IVS Analysis Center. 1. General Information The Matera VLBI station became operational at the Space Geodesy Center (CGS) of the Italian Space Agency (ASI) in May 1990. Since then it has been active in the framework of the most important international programs. VLBI data analysis activities are performed at CGS for a better understanding of the tectonic motions with specific regard for the European area. The CGS, operated by Telespazio on behalf of ASI, provides full scientific and operational support using the main space geodetic techniques: VLBI, SLR and GPS. The main VLBI data analysis activities at the CGS in the year 2008 were directed towards the realization of a global VLBI solution, named asi2008a, using the CALC/SOLVE software (developed at the GSFC). The main characteristics of this solution are: Data span: 1979.08.03 - 2008.11.07 (3510 sessions) Estimated Parameters: Celestial Frame: right ascension and declination as global parameters for 637 sources Terrestrial Frame: Coordinates and velocities for 92 stations as global parameters Earth Orientation: Unconstrained X pole, Y pole, UT1, Xp rate, Yp rate, UT1 rate, dpsi and deps.
Author
VERY LONG BASE INTERFEROMETRY; GLOBAL POSITIONING SYSTEM; GEODESY; TECTONICS
20090034008 Deutsches Geodaetisches Forschungsinstut, Munich, Germany
DGFI Analysis Center Annual Report 2008
Seitz, Manuela; Drewes, Hermann; Tesmer, Volker; Heinkelmann, Robert; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 255-25; In English; Original contains color and black and white illustrations
Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034008
This report summarizes the activities of the DGFI Analysis Center in 2008 and outlines the planned activities for 2009. 1. General Information The German Geodetic Research Institute (Deutsches Geod atisches Forschungsinstitut, DGFI) is an autonomous and independent research institution located in Munich. It is run by the German Geodetic Commission (Deutsche Geod atische Kommission, DGK) at the Bavarian Academy of Sciences. The research covers all fields of geodesy and includes participation in national and international projects as well as functions in international bodies (see also http://www.dgfi.badw.de). Homogeneously reprocessed VLBI and GPS height series from 1994 to 2007 were compared. The data analysis used fully adapted state-of-the-art models (such as VMF1 and a priori zenith delays from ECMWF) for the GPS (at GFZ and at TUM with Bernese 5.1) and VLBI (at DGFI with OCCAM 6.1, LSM) processing. The series were compared in terms of long term non-linear behaviour and harmonic and mean annual signals (derived by averaging the positions of all years into one "mean year"). The mean annual signals are quite similar for VLBI and GPS (Figure 1), if the VLBI data is available with an appropriate density. The two almost independent observing techniques show the same mean annual signals at nearly all co-located sites. Therefore we assume that the annual signals can be geophysically interpreted as integral vertical deformations. In order to study regional effects, the stations of one region (with a dimension of some thousand kilometers) with a similar mean annual signal are grouped into a cluster. Accordingly 55 clusters are defined. To illustrate the clusters, and how diverse the signals from clustered sites can be, the results for the European region are displayed in Figure 2. They confirm that the signals reflect regional deformations, not local or technical artifacts. The most important findings from this study are that (1) for most sites, an annual harmonic function is not a sufficent approximation and that (2) the variations of station heights are regional effects and are induced by mass load variations. For each of the 55 clusters, a regional average mean annual signal was computed. They can be used as a tool to validate geophysical models. 2. Atmospheric loading coefficients determined
Author
VERY LONG BASE INTERFEROMETRY; GEODESY; GLOBAL POSITIONING SYSTEM; HARMONIC FUNCTIONS; WEATHER FORECASTING; POLLUTION TRANSPORT; GEOPHYSICS
20090034009 Massachusetts Inst. of Tech., Westford, MA, United States
Haystack Observatory VLBI Correlator
Titus, Mike; Cappallo, Roger; Corey, Brian; Dudevoir, Kevin; Niell, Arthur; Whitney, Alan; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 205-20; In English; Original contains color illustrations
Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034009
This report summarizes the activities of the Haystack Correlator during 2008. Highlights include correlation of many broadband delay (VLBI2010) experiments and installation at WACO of the correlator run-time software that had been converted to Linux. Problems with bad disks and serial links were investigated. Real-time e-VLBI development for Mark 5B, non-real-time e-VLBI transfers, and engineering support of other correlators continued.
Author
VERY LONG BASE INTERFEROMETRY; CORRELATORS; BROADBAND; REAL TIME OPERATION; UNIX (OPERATING SYSTEM)
20090034011 Shanghai Astronomical Observatory, China
SHAO Analysis Center 2008 Annual Report
Li, Jinling; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 302-30; In English
Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034011
Our research activities in 2008 are related to astrometric and geodetic VLBI experiments and data analysis, the astrometry of massive star-forming regions and luminous red supergiants, the processing of VLBI tracking data of satellites, and antenna site surveys. These activities will be continued in the next year. We will prepare software for the next Chinese lunar and Martian exploration projects.
Author
ASTROMETRY; LUNAR EXPLORATION; GEODESY; VERY LONG BASE INTERFEROMETRY; MARS (PLANET); MASSIVE STARS; DIRECTIONAL ANTENNAS
20090034012 NASA Goddard Space Flight Center, Greenbelt, MD, United States
CDDIS Data Center Summary for the IVS 2008 Annual Report
Noll, Carey; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 227-22; In English
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This report summarizes activities during the year 2008 and future plans of the Crustal Dynamics Data Information System (CDDIS) with respect to the International VLBI Service for Geodesy and Astrometry (IVS). Included in this report are background information about the CDDIS, the computer architecture, staff supporting the system, archive contents, and future plans for the CDDIS within the IVS. 1. Introduction The Crustal Dynamics Data Information System (CDDIS) has supported the archiving and distribution of Very Long Baseline Interferometry (VLBI) data since its inception in 1982. The CDDIS is a central facility providing users access to raw and analyzed data to facilitate scientific investigation. The CDDIS archive of GNSS (GPS and GLONASS), laser ranging, VLBI, and DORIS data is stored on-line for remote access. Information about the system is available via the Web at the URL http://cddis.gsfc.nasa.gov. The current and future plans for the system s support of the IVS are discussed below.
Author
VERY LONG BASE INTERFEROMETRY; GLOBAL POSITIONING SYSTEM; INFORMATION SYSTEMS; ON-LINE SYSTEMS; DATA SYSTEMS; LASER RANGING; ASTROMETRY
20090034013 Academy of Sciences (Russia), Saint Petersburg, Russian Federation
Zelenchukskaya Radio Astronomical Observatory
Dyako, Andrei; Smolentsev, Sergey; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 188-19; In English; Original contains black and white illustrations
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This report briefly summarizes the observational activities at the Zelenchukskaya 32-m VLBI station during the year 2008. 1. General Information Zelenchukskaya Radio Astronomical Observatory was founded by Institute of Applied Astron- omy (IAA) as one of three stations of the Russian VLBI network QUASAR. The sponsoring organization of the project is the Russian Academy of Sciences (RAS). The Zelenchukskaya Radio Astronomical Observatory is situated in Republic Karachaevo-Cherkessiya (Northern Caucasia) about 70 km south of Cherkessk, near to the Zelenchukskaya site (not far from Radiotelescope RATAN-600). The geographic location of the observatory is shown on the IAA RAS Web site: http://www.ipa.nw.ru/PAGE/koi8-r/DEPOBSERV/rus zel.htm. The basic instruments of the ob- servatory are a 32-m radio telescope and technical systems for doing VLBI observations.
Author
RADIO TELESCOPES; RADIO ASTRONOMY; ASTRONOMICAL OBSERVATORIES; POSITION (LOCATION); VERY LONG BASE INTERFEROMETRY
20090034014 Forschungseinrichtung Satellitengeodaesie (FENG), Wettzell, Germany
Fundamentalstation Wettzell - 20m Radiotelescope
Neidhardt, Alexander; Kronschnabl, Gerhard; Schatz, Raimund; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 180-18; In English; Original contains color illustrations
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The 20m-radiotelescope at Wettzell, Germany again contributed very successfully and strongly to the IVS observing program in 2008. Technical changes, improvements, and upgrades were made to increase the reliability of the entire VLBI observing system.
Author
RADIO TELESCOPES; VERY LONG BASE INTERFEROMETRY; GLOBAL POSITIONING SYSTEM; LUNAR RANGEFINDING; METEOROLOGICAL PARAMETERS; SATELLITE LASER RANGING; GEODETIC SURVEYS; GRAVIMETERS
20090034015 Observatorio Astronomico Nacional, Alcala de Henares, Spain
Instituto Geografico Nacional of Spain
Colomer, Francisco; deVicente, Pablo; Gomez-Gonzalez, Jesus; Lopez-Fernandez, Jose Antonio; Espada, Susana Garcia; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 184-18; In English; Original contains color illustrations
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This report updates the description of the OAN facilities as an IVS network station. The new 40-m radiotelescope performed the first geodetic VLBI observations in September 2008. While commissioning for other frequencies is in progress, the instrument will participate regularly in IVS campaigns in 2009. 1. General Information: the IGN Facilities at OAN-Yebes The Observatorio Astron omico Nacional (OAN) of Spain is a department of the Instituto Geografico Nacional (IGN, Ministerio de Fomento) and operates a new 40-m radiotelescope at Yebes (Guadalajara, Spain). The facility also includes an old 14-m radiotelescope, which was a network station of the IVS and participated regularly in the geodetic VLBI campaigns until 2003. It is being refurbished to become a tracking station for the next space radiotelescope VSOP-2. Yebes is also the reference station for the Spanish GPS network. A building has been finished to hold the IGN gravimeters.
Author
GLOBAL POSITIONING SYSTEM; GRAVIMETERS; RADIO TELESCOPES; VERY LONG BASE INTERFEROMETRY; TRACKING STATIONS; GEODESY
20090034016 Massachusetts Inst. of Tech., Westford, MA, United States
IVS Technology Coordinator Report
Whitney, Alan; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 89-9; In English
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In 2008 the Technology Coordinator was active in the following areas: 1) support of work to implement a new geodetic VLBI system as outlined in the IVS Working Group 3 VLBI2010 study, 2) continued development and deployment of e-VLBI, 3) organization of the 7th Annual e-VLBIWorkshop held at Shanghai Observatory in Shanghai, China, and 4) development of the VLBI Data Interchange Format (VDIF) specification. We will briefly describe each of these activities.
Author
VERY LONG BASE INTERFEROMETRY; GEODESY; DEPLOYMENT
20090034017 Bundesamt fuer Kartographie und Geodaesie, Frankfurt am Main, Germany
German Antarctic Receiving Station (GARS) O'Higgins
Ploetz, Christian; Wojdziak, Reiner; Kilger, Richard; Neidhardt, Alexander; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 142-14; In English; Original contains color illustrations
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In 2008 the German Antarctic Receiving Station (GARS) in O'Higgins contributed to the IVS observing program with 10 observation sessions. The timing system was enhanced with a rubidium clock, and the cesium clock was reinstated after repair. First VLBI sessions were completely remote-controlled by starting, attending, and finishing them from Wettzell observatory using a remote extension developed for the Field System at Wettzell.
Author
OBSERVATORIES; VERY LONG BASE INTERFEROMETRY; TIME MEASUREMENT; TIMING DEVICES
20090034018 Norwegian Mapping Authority, Honefoss, Norway
Ny-Alesund 20-Meter Antenna
Ardal, Ole Bjorn; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 139-14; In English
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For the year 2008, the 20-meter VLBI antenna at the Geodetic Observatory, Ny-Alesund, has participated in VLBI experiments, observing 68 of 78 scheduled 24-hour experiments and 36 of 45 scheduled Intensives. Reasons for the lost experiments were the personnel situation and some problems with the dewar/coldhead during spring. Several experiments also had to be run with a warm receiver due to the latter problem. During fall there was a problem with the X-Band cable and the local oscillator that had to be changed. In 2008, Ny-Alesund was a three-person station until July when Inge Sanden s contract ended and then continued as a two-person station until the CONT08, when Inge Sanden and Svein Rekkedal helped out for some time. After CONT08, until mid-September, the station was only manned by one person followed by a brief period of no observations due to a lack of operators. Ole Bjorn Ardal s contract ended in the end of August, and he agreed on a new one-year contract starting in the end of September. Helge Digre's contract also ended this year. With no renewal, he finished his contract period on 31 October after having worked 11 years for the NMA. In October two new operators were employed and started their training: Carl Petter Nielsen and Geir Mathiassen, both on part-time contracts. Their work schedule is basically three months of work followed by one month off. This caused the station to become a two-person station during December, except for Christmas when only one person manned the station. From July on, except for August, the maintenance and repair were done at a minimum level, given the personnel situation. No responses were made to any alarms, and no errors were corrected during unmanned operation. Ny-Alesund is a Mark 5A station.
Author
GEODESY; VERY LONG BASE INTERFEROMETRY; ANTENNAS; GRAVIMETRY
20090034019 Bonn Univ., Germany
The Bonn Geodetic VLBI Operation Center
Nothnagel, A.; Mueskens, A.; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 193-19; In English; Original contains color illustrations
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The IGGB Operation Center has continued to organise and schedule the IVS-T2, IVS-OHIG, IVS-INT3, and EUROPE sessions. 1. Center Activities The IGGB VLBI Operation Center is located at the Institute of Geodesy and Geoinformation of the University of Bonn, Nussallee 17, D-53115 Bonn, Germany. It has been organizing and scheduling VLBI observing sessions for more than twenty years. The observing series organized and scheduled in 2008 are the same as in 2007.
Author
GEODESY; SCHEDULING; VERY LONG BASE INTERFEROMETRY; SCHEDULES
20090034020 Academy of Sciences of the Ukraine, Kiev, Ukraine
IVS Analysis Center at Main Astronomical Observatory of National Academy of Sciences of Ukraine
Bolotin, Sergei; Lytvyn, Svitlana; Yatskiv, Yaroslav; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 285-28; In English
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This report summarizes the activities of the VLBI Analysis Center at the Main Astronomical Observatory of the National Academy of Sciences of Ukraine in 2008. 1. Introduction The VLBI Analysis Center was established in 1994 by the Main Astronomical Observatory (MAO) of the National Academy of Sciences of Ukraine (NASU) as a working group of the Department of Space Geodynamics of the MAO. In 1998 the group started its IVS membership as an IVS Analysis Center. The AC MAO is located in the Central office of the observatory in Kiev.
Author
ASTRONOMICAL OBSERVATORIES; VERY LONG BASE INTERFEROMETRY; GEODYNAMICS; ALTERNATING CURRENT
20090034021 Korea Astronomy and Space Science Inst., Korea, Republic of
KASI Combination Center Report
Cho, Jungho; Kwak, Younghee; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 283-28; In English; Original contains color illustrations
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This report introduces the Korea Astronomy and Space Science Institute (KASI) and describes the planned activities of the KASI as an IVS Combination Center. 1. General Information The proposal of the Korea Astronomy and Space Science Institute (KASI) for becoming an IVS combination center was accepted on October 21, 2008. KASI is one of the affiliated organizations of IVS. KASI Headquarters is located in the Daeduk research and development complex, Daejeon. The Space Geodesy research of KASI was started in 1992 with GPS. Now the KASI Space Geodesy research division is composed of three groups including the Earth Observing System (EOS) research group. The EOS research areas are based on Space Geodetic techniques such as GNSS, VLBI, SLR and Gravimeter and are focused on the changes of the Earth s shape and its geodynamics. The EOS research group also works on the applications of Space Geodesy such as an early warning system of natural hazards. The EOS group will be in charge of an IVS combination center as an extension of research on the Earth s shape changes
Author
GLOBAL POSITIONING SYSTEM; EARTH OBSERVING SYSTEM (EOS); EARLY WARNING SYSTEMS; GEODESY; GEODYNAMICS; GRAVIMETERS; VERY LONG BASE INTERFEROMETRY
20090034022 National Inst. of Information and Communications Technology, Ibaraki, Japan
Analysis Center at National Institute of Information and Communications Technology
Hobiger, Thomas; Takiguchi, Hiroshi; Ichikawa, Ryuichi; Sekido, Mamoru; Koyama, Yasuhiro; Kondo, Tetsuro; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 287-29; In English; Original contains black and white illustrations
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This report summarizes the activities of the Analysis Center at the National Institute of Information and Communications Technology (NICT) for the year 2008. 1. General Information The NICT Analysis Center is located in Kashima, Ibaraki, Japan and is operated by the spacetime standards group of NICT. Analysis of VLBI experiments and related study fields at NICT are mainly concentrated on experimental campaigns for developing new techniques such as e-VLBI for real-time EOP determination, prototyping of a compact VLBI system, time and frequency transfer, atmospheric path delay studies, and improvement of the accuracy of space geodetic techniques.
Author
SPACE-TIME FUNCTIONS; GEODESY; INFORMATION SYSTEMS; REAL TIME OPERATION; VERY LONG BASE INTERFEROMETRY
20090034023 Istituto di Radioastronomia, Bologna, Italy
Noto Station Status Report
Tuccari, G.; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 136-13; In English; Original contains color illustrations
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This brief report summarizes the main activities of the Observatory of Noto in 2008.
Author
OBSERVATORIES; ANTENNAS; DIGITAL TECHNIQUES
20090034024 NASA Goddard Space Flight Center, Greenbelt, MD, United States; Kokee Park Geophysical Observatory, Waimea, HI, United States
Kokee Park Geophysical Observatory
Kim, Kelly; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 122-12; In English; Original contains color illustrations
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This report summarizes the technical parameters and the staff of the VLBI system at Kokee Park Kauai.
Author
VERY LONG BASE INTERFEROMETRY; GEODESY
20090034025 Academy of Sciences (Russia), Saint Petersburg, Russian Federation
Badary Radio Astronomical Observatory
Smolentsev, Sergey; Sergee, Roman; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 95-9; In English; Original contains color and black and white illustrations
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This report provides information about the Badary network station: general information, facilities, staff, present status and outlook.
Author
RADIO TELESCOPES; VERY LONG BASE INTERFEROMETRY; ASTRONOMICAL OBSERVATORIES; QUASARS
20090034026 Istituto di Radioastronomia, Bologna, Italy
The Medicina Station Status Report
Orfei, Alessandro; Orlati, Andrea; Maccaferri, Giuseppe; Mantovani, Franco; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 130-13; In English; Original contains color illustrations
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General information about the Medicina Radio Astronomy Station, the 32m antenna status, and the staff in charge of VLBI observations are provided. In 2008 the data from geodetic VLBI observations were acquired using the Mark 5A recording system with good results. Updates of the hardware have been performed and are briefly described.
Author
GEODETIC SURVEYS; RADIO ASTRONOMY; VERY LONG BASE INTERFEROMETRY; ANTENNAS; GEODESY
20090034027 Italian Space Agency, Matera, Italy
Matera CGS VLBI Station
Bianco,Giuseppe; Colucci, Giuseppe; Schiavone, Francesco; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 126-12; In English; Original contains color illustrations
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This report describes the status of the Matera VLBI station. Also an overview of the station, some technical characteristics of the system and staff addresses are given.
Author
VERY LONG BASE INTERFEROMETRY; RADIO ASTRONOMY; RADIO ANTENNAS
20090034028 Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA, United States
JPL VLBI Analysis Center Report for 2008
Jacobs, Chris; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 272-28; In English; Original contains color illustrations
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This report describes the activities of the JPL VLBI analysis center for the year 2008. We continue to do celestial reference frame, terrestrial reference frame, earth orientation, and spacecraft navigation work using the VLBI technique. There are several areas of our work that are undergoing active development. An important development was moving our earth orientation and reference frame work completely to Mark 5A recording and software correlation by the end of 2008. Our international collaboration to build celestial frames at K- (24 GHz) and Q-bands (43 GHz) matured to near a part-per-billion accuracy as documented in two submitted papers. Our in-house work to build a reference at X/Ka-bands (8.4/32 GHz) is also close to ppb accuracy. We supported the Phoenix Mars lander and other missions with VLBI navigation measurements. We continue to study ways to improve spacecraft tracking using VLBI techniques.
Author
VERY LONG BASE INTERFEROMETRY; CELESTIAL REFERENCE SYSTEMS; EARTH ORIENTATION; SPACE NAVIGATION; SUPERHIGH FREQUENCIES
20090034029 Academy of Sciences (Russia), Saint Petersburg, Russian Federation
IAA VLBI Analysis Center Report 2008
Skurikhina, Elena; Kurdubov, Sergey; Gubanov, Vadim; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 269-27; In English; Original contains black and white illustrations
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This report presents an overview of IAA VLBI Analysis Center activities during 2008 and the plans for the coming year. 1. General Information The IAA IVS Analysis Center (IAA AC) is located at the Institute of Applied Astronomy of the Russian Academy of Sciences in St. Petersburg, Russia. IAA AC contributes to IVS products, such as daily SINEX files, TRF, CRF, rapid and long-term series of EOP, baseline length, and tropospheric parameters. Source position time series and CRF have been calculated within the scope of the IERS/IVS Working Group on the Second Realization of the ICRF. Several ways of source selection with NNR constraints were proposed and tested. EOP, UT1-UTC, and station positions were estimated from domestic observation programs RU-E and RU-U. AC IAA generates NGS files.
Author
INFORMATION SYSTEMS; PLASMA HEATING; RADIO FREQUENCY HEATING; TIME SERIES ANALYSIS; VERY LONG BASE INTERFEROMETRY; ION CYCLOTRON RADIATION
20090034030 Natural Resources Canada, Ottawa, Ontario, Canada
Design Aspects of the VLBI2010 System - Progress Report of the IVS VLBI2010 Committee
Petrachenko, Bill; Niell, Arthur; Behrend, Dirk; Corey, Brian; Bohm, Johannes; Charlot, Patrick; Collioud, Arnaud; Gipson, John; Haas, Rudiger; Hobiger, Thomas; Koyama, Yasuhiro; MacMillan, Dan; Malkin, Zinovy; Nilsson, Tobias; Pany, Andrea; Tuccari, Gino; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 13-6; In English; Original contains color illustrations
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In September 2005 the IVS Directing Board accepted the final report of its Working Group 3 (WG3) entitled wVLBI2010: Current and Future Requirements for Geodetic VLBI Systems . This bold vision for the future recommended a review of all current VLBI systems and processes from antennas to analysis and outlined a path to a next-generation system with unprecedented new capabilities: h 1-mm position accuracy on global scales, h continuous measurements for time series of station positions and Earth orientation parameters, h turnaround time to initial geodetic results of less than 24 hours. Immediately following the acceptance of the WG3 final report, the IVS established the VLBI2010 Committee (V2C) to carry out a series of studies recommended by WG3 and to encourage the realization of the new vision for geodetic VLBI. Since its inception, the V2C has accomplished much towards this goal. This report summarizes the work of the committee through the end of 2008.
Author
VERY LONG BASE INTERFEROMETRY; TIME SERIES ANALYSIS; GEODESY; EARTH ORIENTATION; POSITION ERRORS
20090034031 Academia Sinica, Urumqi, China
Nanshan VLBI Station Report for 2008
Yusup, Aili; Liu, Xiang; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 173-17; In English
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The Nanshan 25-meter radio telescope is operated by Urumqi Observatory. This report describes the activities and the status of Nanshan VLBI station as an IVS network station in 2008. 1. Introduction The station is located 70 km south of Urumqi, the capital city of Xinjiang Uygur Autonomous Region of China. The station is affiliated with the Urumqi Observatory of the National Astronom- ical Observatories, CAS. We contribute to IVS in geodetic VLBI observations. The Nanshan VLBI station has participated in domestic VLBI experiments and as one of the VLBI ground stations tracking the Chinese Chang E satellite. Urumqi also participated in the Japanese SELENE obser- vations. The telescope participated in real-time experiments among the Chinese VLBI Network. We are grateful for the kind help and support from the VLBI experts within the IVS community. The Urumqi Observatory is willing to continue the collaboration in international VLBI activities.
Author
REAL TIME OPERATION; RADIO TELESCOPES; GEODETIC SURVEYS; VERY LONG BASE INTERFEROMETRY; AUTONOMY; GROUND STATIONS
20090034032 National Astronomical Observatory, Oshu, Japan
VERA Geodetic Activities
Jike, Takaaki; Manabe, Seiji; Tamura, Yoshiaki; Shizugami, Makoto; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 132-13; In English; Original contains color and black and white illustrations
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This report describes the status of the VERA network in the context of geodetic VLBI. The main about its technical parameters and a summary of its geodetic VLBI activities
Author
GEODESY; VERY LONG BASE INTERFEROMETRY; RADIO ASTRONOMY
20090034033 National Inst. of Information and Communications Technology, Japan
Kashima 34-m Radio Telescope
Kawai, Eiji; Sekido, Mamoru; Ichikawa, Ryuichi; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 114-11; In English; Original contains color and black and white illustrations
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The Kashima 34-m radio telescope is continuously operated and maintained by the National In- stitute of Information and Communications Technology (NICT) as a facility of the Kashima Space Research Center (KSRC) in Japan. This brief report summarizes the status of this telescope, the staff and activities during 2008. The Kashima 34-m radio telescope (Figure 1 left) was constructed as a main station of the "Western Pacific VLBI Network Project" in 1988. After that project s termination, the telescope has been used not only for geodetic purposes but also for astronomy and other purposes. The station is located about 100 km east of Tokyo, Japan and co-located with the 11-m radio telescope and the International GNSS Service station (KSMV) (Figure 1 right). This station is maintained by the Space-Time Measurement Project of the Space-Time Standards Group of KSRC, NICT.
Author
VERY LONG BASE INTERFEROMETRY; RADIO TELESCOPES; GEODESY; INFORMATION SYSTEMS
20090034034 Istituto di Radioastronomia, Bologna, Italy
Italy INAF Data Center Report
Neguisini, M.; Sarti, P.; Abbondanza, C.; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 230-23; In English
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This report summarizes the activities of the Italian INAF VLBI Data Center. Our Data Center is located in Bologna, Italy, and belongs to the Institute of Radioastronomy, which is part of the National Institute of Astrophysics. We also report about some changes in the hardware facilities devoted to IVS activities.
Author
VERY LONG BASE INTERFEROMETRY; GLOBAL POSITIONING SYSTEM; DATA BASES; GEODESY; ASTROPHYSICS
20090034035 Geographical Survey Inst., Tsukuba, Japan
Tsukuba 32-m VLBI Station
Tanimoto, Daisuke; Kurihara, Shinobu; Kokado, Kensuke; Matsuzaka, Shigeru; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 169-17; In English; Original contains color and black and white illustrations
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The Tsukuba 32-m radio telescope is operated by the Geographical Survey Institute (GSI) VLBI group. This report summarizes the current status and the future plans of the Tsukuba 32-m VLBI station. We participated in a total of 208 domestic and international VLBI sessions in accordance with the IVS 2008 observing plan. The CONT08 campaign in August was the highlight of the year. In experimental sessions in 2008, we achieved an extremely rapid UT1 measurement latency of 3 minutes 45 seconds for an ultra-rapid dUT1 experiment in February. We started 32 Mbps/ch observing using K5/VSSP32 this year. The Tsukuba 32-m VLBI station (TSUKUB32) is located at GSI in Tsukuba Science City, which is about 50 km to the northeast of the capital Tokyo. GSI has four VLBI stations; TSUKUB32, AIRA, CHICHI10, and SINTOTU3. These four stations form our domestic VLBI network named GARNET (GSI Advanced Radio telescope NETwork). We have performed our domestic VLBI observations using GARNET. One series of sessions is named JADE (JApanese Dynamic Earth observation by VLBI). The main purposes of the JADE series are to define the reference frame of Japan and to monitor the plate motions for the advanced study of crustal deformations. The GARNET stations, centered on TSUKUB32, are located to cover the Japanese mainland. The GARNET stations other than TSUKUB32 joined international VLBI sessions this year.
Author
VERY LONG BASE INTERFEROMETRY; RADIO TELESCOPES; EARTH OBSERVATIONS (FROM SPACE); DYNAMIC TESTS; DEFORMATION; CRUSTS; COORDINATES
20090034036 Massachusetts Inst. of Tech., Westford, MA, United States
Westford Antenna
Poirier, Mike; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 176-17; In English; Original contains color illustrations
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Technical information is provided about the antenna and VLBI equipment at the Westford site of Haystack Observatory and about changes to the systems since the IVS 2007 Annual Report. 1. Westford Antenna at Haystack Observatory Since 1981 the Westford antenna has been one of the primary geodetic VLBI sites in the world. Located 70 km northwest of Boston, Massachusetts, the antenna is part of the MIT Haystack Observatory complex. The Westford antenna was constructed in 1961 as part of the Lincoln Laboratory Project West Ford that demonstrated the feasibility of long-distance communication by bouncing radio signals off a spacecraft-deployed belt of copper dipoles at an altitude of 3,600 km. In 1981 the antenna was converted to geodetic use as one of the first two VLBI stations in the National Geodetic Survey Project POLARIS. Westford has continued to perform geodetic VLBI observations on a regular basis since 1981. Westford has also served as a test bed in the development of new equipment and techniques now employed in geodetic VLBI worldwide. Primary funding for geodetic VLBI at Westford is provided by the NASA Space Geodesy Program.
Author
RADIO SIGNALS; VERY LONG BASE INTERFEROMETRY; ANTENNAS; GEODETIC SURVEYS; GEODESY; OBSERVATORIES; RADOMES
20090034037 Deutsches Geodaetisches Forschungsinstut, Munich, Germany; Bundesamt fuer Kartographie und Geodaesie, Frankfurt am Main, Germany
BKG/DGFI Combination Center Annual Report 2008
Scwegmann, Wolfgang; Gerstl, Michael; Heinkelmann, Robert; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 250-25; In English
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This report summarizes the activities of the BKG/DGFI Combination Center in 2008 and outlines the planned activities for the year 2009. 1. General Information The BKG/DGFI Combination Center has been established jointly by the Federal Agency for Cartography and Geodesy (Bundesamt f ur Kartographie und Geod asie, BKG) and the German Geodetic Research Institute (Deutsches Geod atisches Forschungsinstitut, DGFI). BKG is a German federal authority assigned to the Federal Ministry of the Interior. Its tasks include, among others, the provision of geodetic reference data and basic spatial data for the needs of the Federal Government-the administrative, economic, and scientific sectors-as well as for the citizens. DGFI is an autonomous and independent research institution located in Munich. It is run by the German Geodetic Commission (Deutsche Geod atische Kommission, DGK) at the Bavarian Academy of Sciences. The research covers all fields of geodesy and includes the participation in national and international projects as well as functions in international bodies. The joint BKG/DGFI Combination Center was inaugurated by the IVS Directing Board in October 2008. The tasks of this IVS Combination Center include quality control and a timely combination of the session-based intermediate results of the IVS Analysis Centers into a final combination product (e.g., Earth Orientation Parameters, EOP). After consultation with the IVS Analysis Coordinator, the combination results will be released as official IVS products. The Combination Center is also expected to contribute to the generation of the official IVS input to any ITRF activities. These tasks should be performed on an operational basis.
Author
EARTH ORIENTATION; QUALITY CONTROL; ECONOMICS; GEODESY; AUTONOMY
20090034038 Wien Univ., Austria
Vienna IGG Special Analysis Center Annual Report 2008
Schuh, Harald; Boehm, Johannes; Englich, Sigrid; Heinkelmann, Robert; MendesCerveira, Paulo Jorge; Pany, Andrea; Plank, Lucia; Spicakova, Hana; Teke, Kamil; Wresnik, Joerg; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 273-27; In English; Original contains color illustrations
Contract(s)/Grant(s): Proj. P16992-N10; Proj. P18404-N10; Proj. 22353; SCHU 1103/301
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The main activities of the Institute of Geodesy and Geophysics (IGG) at the Vienna University of Technology in 2008 have been the contribution to the VLBI2010 simulations and the development of new VLBI software based on Matlab. Furthermore, studies about Earth rotation and reference frames have been continued. 1. General Information The Institute of Geodesy and Geophysics (IGG) is part of the Faculty of Mathematics and Geoinformation of the Vienna University of Technology. It is divided into three research units, one of them focusing on advanced geodesy (mathematical and physical geodesy, space geodesy). Within this research unit, one group (out of four) is dealing with geodetic VLBI.
Author
GEOPHYSICS; VERY LONG BASE INTERFEROMETRY; COMPUTER PROGRAMMING; GEODESY
20090034039 Istituto di Radioastronomia, Bologna, Italy
Italy INAF Analysis Center Report
Negusini, M.; Sarti, P.; Abbondanza, C.; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 277-27; In English
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This report summarizes the activity of the Italian INAF VLBI Analysis Center. Our Analysis Center is located in Bologna, Italy and belongs to the Institute of Radioastronomy, which is part of the National Institute of Astrophysics. IRA runs the observatories of Medicina and Noto, where two 32 m VLBI AZ-EL telescopes are situated. This report contains the AC s VLBI data analysis activities and shortly outlines the investigations carried out at Medicina and Noto concerning gravitational deformations of the VLBI telescopes. 1. Current Status and Activity Data analysis of terrestrial surveys carried out during 2008 focused on the investigation of deformation under the effects of gravity and, in particular, on the possibility of inferring a general model for gravitational deformations of large VLBI telescopes. The strategy used relies on the combination of different metrological approaches applied to the antennas: on one hand, classical terrestrial surveys executed via forward intersections on some specific targets located on the tele- scope s primary reflector and on the quadrupod; on the other, laser scanning surveys which allow analysts to infer a more continuous representation of the parabolic mirror deformation. A third kind of information was derived from Finite Element Modelling (FEM) which provides a scenario of feasible deformations of the antenna structure at its peculiar nodes under the influence of its own weight. The joint usage of these data types permitted us to identify, quantify and detach the effects of gravitational deformations: according to [1], these latter can be decomposed into a (i) paraboloid s vertex displacement, (ii) relative motion of the S/X receivers placed in the primary focus with respect to the antenna primary reflector, (iii) a focal length variation induced by deformations of the VLBI reflector. This combination approach might offer valuable help for estimating a signal path variation model induced by gravity to be applied within VLBI data processing. Concerning the laser scanning measurement analysis, a specific focal length variation model, valid for the Medicina and Noto antennas, was derived with the aim of supplying a model which can account for the relative change in focal length as the VLBI antenna is steered in elevation; results of these considerations can be found in [2], which has been reviewed and is in the course of publication
Author
RADIO ASTRONOMY; VERY LONG BASE INTERFEROMETRY; GRAVITATIONAL EFFECTS; ASTROPHYSICS; METROLOGY; LASER APPLICATIONS; FINITE ELEMENT METHOD; ALTERNATING CURRENT
20090034040 Bonn Univ., Germany
Analysis Coordinator Report
Nothnagel, A.; Boeckmann, S.; Artz, T.; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 80-8; In English; Original contains black and white illustrations
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IVS analysis coordination issues in 2008 are reported here. Routine EOP combinations on the basis of datum-free normal equations have been continued. For this, it was necessary to compute a new realization of a terrestrial reference frame. Investigations have been carried out on certain quality aspects of the IVS EOP series. 1. General Issues The "Ninth IVS Analysis Workshop" was held at the Institute of Applied Astronomy, St. Petersburg, Russia, on March 7, 2008, in connection with the Fifth IVS General Meeting. The workshop was attended by more than 40 participants who enjoyed being hosted by the IAA with an impressive look onto the still winterly Neva. More details on the workshop can be found in Nothnagel (2008a).
Author
TIME SERIES ANALYSIS; COORDINATES; LOGISTICS; MATRICES (MATHEMATICS); VARIANCE (STATISTICS); UNIVERSAL TIME; DERIVATION
20090034041 TIGO, Chile
Geodetic Observatory TIGO in Concepcion
Sobarzo, Sergio; Onate, Eric; Jara, Cristobal; Herrera, Cristian; Zaror, Pedro; Duguet, Cristian; Soto, Miguel; Hase, Hayo; Boeer, Armin; Sierk, Bernd; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 165-16; In English; Original contains color and black and white illustrations
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During the seventh year of operation in Chile, TIGO carried out 110 successful VLBI observations. Activities of the VLBI group at TIGO during 2008 and an outlook for 2009 are given.
Author
VERY LONG BASE INTERFEROMETRY; OBSERVATORIES; GEODESY; LATITUDE; LONGITUDE
20090034042 NVI, Inc., Greenbelt, MD, United States
Network Coordinator Report
Himwich, Ed; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 83-8; In English
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This report includes an assessment of the network performance in terms of lost observing time for the 2008 calendar year. Overall, the observing time loss was about 15.1%, an increase of about 3.7% from the previous year. A table of relative incidence of problems with various subsystems is presented. The most significant identified causes of loss were antenna reliability (accounting for about 19.2%), RFI (14.8%), and receiver problems (13.8%), Unidentified problems accounted for about 17.7% of the loss. There are prospects for Korea, India, and New Zealand to start contributing to IVS. New antennas are being purchased by Australia and New Zealand.
Author
COMPUTER NETWORKS; VERY LONG BASELINE ARRAY (VLBA); INFORMATION SYSTEMS; CORRELATORS; LIBRARIES
20090034043 Auckland Univ., New Zealand
New Zealand 12-m VLBI Station for Geodesy and Astronomy
Gulyaev, Sergei; Natusch, Tim; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 68-7; In English; Original contains color and black and white illustrations
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This report summarizes the radio astronomical and VLBI activities recently started in New Zealand. It provides geographical and technical details of a new 12-m geodetic VLBI antenna being operated by Auckland University of Technology. Details of the VLBI system to be installed in the station are outlined. A co-located GNSS station and specialized surveying equipment are also described. 1. Introduction The IVS report [1] proposes a number of strategies to improve the long-term accuracy of geodetic VLBI with an eye to achieving 1 mm long-term accuracy on baselines. Among these strategies are: "to increase the number of antennas and improve their geographic distribution" and "to increase the number of observations per unit of time". These IVS strategies can best be addressed through construction of new small (10-12 m), fast moving antennas in areas that are under-represented (Australia) or lack geodetic VLBI stations (New Zealand).
Author
ASTRONOMY; VERY LONG BASE INTERFEROMETRY; CONSTRUCTION; SURVEYS; GEODESY
20090034044 NVI, Inc., Greenbelt, MD, United States
Coordinating Center Report
Behrend, Dirk; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 77-7; In English; Original contains color illustrations
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This report summarizes the activities of the IVS Coordinating Center during the year 2008 and forecasts activities planned for the year 2009. 1. Coordinating Center Operation The IVS Coordinating Center is based at the Goddard Space Flight Center and is operated by NEOS (National Earth Orientation Service), a joint effort for VLBI by the U.S. Naval Observatory and the NASA Goddard Space Flight Center. The mission of the Coordinating Center is to provide communications and information for the IVS community and the greater scientific community and to coordinate the day-to-day and long-term activities of IVS. The Web server for the Coordinating Center is provided by Goddard.
Author
COMMUNICATION; EARTH ORIENTATION; VERY LONG BASE INTERFEROMETRY; FORECASTING
20090034045 Geographical Survey Inst., Tsukuba, Japan
Tsukuba VLBI Correlator
Shigematsu, Hiromi; Kurihara, Shinobu; Kokado, Kensuke; Nozawa, Kentarou; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 216-21; In English; Original contains black and white illustrations
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This is a report of the activities at the Tsukuba VLBI Correlator in 2008. The Tsukuba VLBI Correlator processed 99 intensive sessions (IVS-INT2), nine JADE sessions and two geodetic sessions for JAXA. Additionally, we processed ultra-rapid dUT1 e-VLBI experiments and obtained UT1-TAI only 3 minutes 45 seconds after the end of the observing sessions. 1. General Information The Tsukuba VLBI Correlator is situated at the Geographical Survey Institute (GSI) in Tsukuba, Japan. It is a part of the VLBI components operated by GSI, together with the Tsukuba 32-m VLBI station (TSUKUB32). There are two K5/VSSP correlator units. Intensive sessions (IVS-INT2), performed on Saturdays and Sundays on the TSUKUB32-WETTZELL baseline for monitoring UT1-UTC, have been correlated at the Tsukuba VLBI Correlator. The processing of the JADE series (geodetic sessions with domestic VLBI network of GSI) is also a major task of the Tsukuba VLBI Correlator.
Author
UNIVERSAL TIME; GEODESY; SURVEYS; VERY LONG BASE INTERFEROMETRY
20090034046 Hartebeesthoek Radio Astronomy Observatory, South Africa
Hartebeesthoek Radio Astronomy Observatory (HartRAO)
International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 107-11; In English; Original contains color and black and white illustrations
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HartRAO, the only fiducial geodetic site in Africa, participates in VLBI, GNSS, and SLR global networks, among others. This report provides an overview of our geodetic VLBI activities during 2008. On the 3rd of October 2008, a critical failure of the 26-m radio telescope put a halt to VLBI observations. 1. Geodetic VLBI at HartRAO Hartebeesthoek is located 65 kilometers northwest of Johannesburg within the World Heritage Site known as the Cradle of Humankind, just inside the provincial boundary of Gauteng, South Africa. The nearest town, Krugersdorp, is 32 km distant. The telescope is situated in an isolated valley which affords protection from terrestrial interference. HartRAO uses a 26-metre equatorially mounted Cassegrain radio telescope built by Blaw Knox in 1961. The telescope was part of the NASA deep space tracking network until 1975 when the facility was converted to an astronomical observatory. The telescope is co-located with an SLR station (MOBLAS-6) and an IGS GNSS station (HRAO). HartRAO joined the EVN as an associate member during 2001. Geodetic VLBI has been allocated 18% of the available telescope time. The allocation for geodetic VLBI was increased from 58 24-hour experiments in 2007 to 65 in 2008 to include the CONT08 campaign.
Author
ASTRONOMICAL OBSERVATORIES; GEODESY; VERY LONG BASE INTERFEROMETRY; TRACKING NETWORKS; SATELLITE LASER RANGING; RADIO TELESCOPES; RADIO ASTRONOMY
20090034047 Universidade Presbiteriana Mackenzie, Sao Paulo, Brazil
Fortaleza Station Report for 2008
Kaufmann, Pierre; PereiradeLucena, A. Macilio; SombradaSilva, Adeildo; Tateyama, Claudio E.; Filho, Avicena; Moreira, Carlos Fabiano B.; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 99-10; In English; Original contains color illustrations
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This is a brief report about the activities carried out at the Fortaleza geodetic VLBI station (ROEN: Radio Observatorio Espacial do Nordeste), located in Eus ebio, CE, Brazil, in 2008. The observing activities consisted of 79 VLBI sessions and continuous GPS monitoring recordings. The installation of optical fiber was completed, and the station switched to a 1 Gbit/s high speed network, to be used in e-VLBI operations. Regular GPS observations were carried out at the same site.
Author
VERY LONG BASE INTERFEROMETRY; OPTICAL FIBERS; HIGH SPEED; SWITCHING; GLOBAL POSITIONING SYSTEM; GEODESY
20090034048 Bundesamt fuer Kartographie und Geodaesie, Frankfurt am Main, Germany
BKG Data Center
Thorandt, Volkmar; Wojdziak, Reiner; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 225-22; In English; Original contains color illustrations
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This report summarizes the activities of the Washington Correlator for the year 2008. The Washington Correlator provides up to 80 hours of processing per week, primarily supporting Earth Orientation and astrometric observations. An additional 40 hours per week of unattended processing is also provided routinely. In 2008 the major programs supported include the IVS-R4, IVS-INT, IVS-R1, CONT08, APSG, and CRF (CRF, CRMS, CRDS, and CRFS) observing sessions. 1. Introduction The Washington Correlator (WACO) is located at and staffed by the U. S. Naval Observatory (USNO) in Washington, DC, USA. The correlator is sponsored and funded by the National Earth Orientation Service (NEOS) which is a joint effort of the USNO and NASA. Dedicated to processing geodetic and astrometric VLBI observations, the facility spent 100 percent of its time on these experiments. All of the weekly IVS-R4 sessions, all of the daily Intensives, several IVS-R1 sessions, and the entire CONT08 were processed at WACO. The remaining time was spent on terrestrial reference frame and astrometry sessions. The facility houses a Mark IV Correlator.
Author
EARTH ORIENTATION; CORRELATORS; ASTROMETRY; VERY LONG BASE INTERFEROMETRY
20090034049 Naval Observatory, Washington, DC, United States
NEOS Operation Center
Kingham, Kerry; Carter, M. S.; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 19; In English
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This report covers the activities of the National Earth Orientation Service (NEOS) Operation Center at US Naval Observatory (USNO) for 2008. The Operation Center schedules IVS-R4 and the INT1 Intensive experiments.
Author
EARTH ORIENTATION; GEODESY
20090034050 Bonn Univ., Germany
The Bonn Astro/Geo Mark IV Correlator
Bernhart, Simone; Bertarini, Alexxandra; Mueskens, Arno; Alef, Walter; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 201-20; In English; Original contains color illustrations
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The Bonn Mark IV VLBI correlator is operated jointly by the Max-Planck-Institut fur Radioastronomie (MPIfR) and the IGG in Bonn and the BKG in Frankfurt. Since 2007, e-VLBI transfers have become routine for geodetic experiments, and, thanks to that, a new Intensive series (INT3) was introduced and is correlated in Bonn. Three Mark 5B units have been installed and are in regular use for stream correlation. In late December 2007, the first phase of a Linux cluster dedicated for the software correlator, which will become the long-term future replacement of the hardware correlator, was installed. Towards the end of 2008 the cluster was extended to 60 nodes with nearly 500 compute-cores and 40 TB of disk storage.
Author
CORRELATORS; GEODESY
20090034051 Crimean Astrophysical Observatory, Russian Federation
Simeiz VLBI Station - H-maser and Mark 5B+ Upgrade
Volvach, A. E.; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 154-15; In English; Original contains color and black and white illustrations
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We summarize briefly the status of the 22-m radio telescope as an IVS Network Station. In 2008 RT-22 was equipped with a modern Mark 5B+ VLBI recording system and a new H-maser. That gives the possibility to continue astrophysical and fundamental geodetic VLBI observations.
Author
VERY LONG BASE INTERFEROMETRY; RADIO ASTRONOMY; RADIO TELESCOPES; GEODETIC SURVEYS; ASTROPHYSICS; GEODESY
20090034052 Naval Observatory, Washington, DC, United States
Washington Correlator
Kingham, Kerry A.; Hall, David M.; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 220-22; In English; Original contains color illustrations
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This report summarizes the activities of the Washington Correlator for the year 2008. The Washington Correlator provides up to 80 hours of processing per week, primarily supporting Earth Orientation and astrometric observations. An additional 40 hours per week of unattended processing is also provided routinely. In 2008 the major programs supported include the IVS-R4, IVS-INT, IVS-R1, CONT08, APSG, and CRF (CRF, CRMS, CRDS, and CRFS) observing sessions. 1. Introduction The Washington Correlator (WACO) is located at and staffed by the U. S. Naval Observatory (USNO) in Washington, DC, USA. The correlator is sponsored and funded by the National Earth Orientation Service (NEOS) which is a joint effort of the USNO and NASA. Dedicated to processing geodetic and astrometric VLBI observations, the facility spent 100 percent of its time on these experiments. All of the weekly IVS-R4 sessions, all of the daily Intensives, several IVS-R1 sessions, and the entire CONT08 were processed at WACO. The remaining time was spent on terrestrial reference frame and astrometry sessions. The facility houses a Mark IV Correlator.
Author
VERY LONG BASE INTERFEROMETRY; ASTROMETRY; EARTH ORIENTATION; GEODETIC SURVEYS; CORRELATORS
20090034053 National Inst. of Information and Communications Technology, Japan
Kashima and Koganei 11-m VLBI Stations
Koyama, Yasuhiro; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 118-12; In English; Original contains color illustrations
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Two 11-m VLBI antennas at Kashima and Koganei used to be stations of the Key Stone Project VLBI Network. The network consisted of four VLBI stations at Kashima, Koganei, Miura, and Tateyama. Since the Miura and Tateyama stations have been transported to Tomakomai and Gifu, the Kashima and Koganei 11-m stations remain as IVS Network Stations. After the regular VLBI sessions with the Key Stone Project VLBI Network terminated in 2001, these stations have been mainly used for the purposes of technical developments and miscellaneous observations. In 2008, a series of geodetic VLBI experiments were performed between the Kashima and Koganei 11-m VLBI stations to evaluate the capability of the VLBI technique for precise time transfer between Time and Frequency laboratories to construct Coordinated Universal Time. Other series of experiments were also carried out for the development of e-VLBI by using the high speed network connection between the sites.
Author
GEODESY; VERY LONG BASE INTERFEROMETRY
20090034054 Tasmania Univ., Hobart, Australia
Hobart, Mt. Pleasant, Station Report for 2008
Lovell, Jim; Dickey, John M.; Reid, Brett; Ellingsen, Simon; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 111-11; In English; Original contains color and black and white illustrations
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This is a brief report on the activities carried out at the Mt. Pleasant Radio Astronomy Observatory at Hobart, Tasmania. During 2008, the observatory participated in 59 IVS VLBI 24-hour observing sessions, and significant progress was made on the AuScope VLBI array which will see three new antennas installed across Australia for geodesy.
Author
VERY LONG BASE INTERFEROMETRY; RADIO ASTRONOMY; GEODESY; OBSERVATORIES
20090034055 Geoscience Australia, Canberra, Australia
Geoscience Australia Analysis Center
Titov, Oleg; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 243-24; In English; Original contains color illustrations
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This report gives an overview about the activities of the Geoscience Australia IVS Analysis Center during 2008.
Author
GEODESY; VERY LONG BASE INTERFEROMETRY; CELESTIAL REFERENCE SYSTEMS
20090034056 Massachusetts Inst. of Tech., Westford, MA, United States
Haystack Observatory Technology Development Center
Niell, Arthur; Whitney, Alan; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 321-32; In English; Original contains color illustrations
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Work at the MIT Haystack Observatory is currently focusing on three areas of technology development: Mark 5C/DBE2 VLBI data system VLBI2010 prototype antenna systems e-VLBI Considerable progress has been made in each of these areas. 1. Mark 5C VLBI Data System The Mark 5C is being designed as the next-generation Mark 5 high rate data recording system. It will have the capability of recording at sustained rates up to 4096 Mbps. An important feature is that the same disk modules will be used as for the Mark 5A and Mark 5B, thus preserving the existing investments in storage media. The Mark 5C data interface for both recording and playback will be 10 Gigabit Ethernet, which is rapidly becoming a widely supported standard. Changing from the hardware-defined VSI-H linkage for the Mark 5B to the network-based interface for the Mark 5C offers both advantages and limitations. For example, data playback through the 10GigE interface is expected to be the natural interface to the large-scale software correlators coming into use. On the other hand, implementing the 10GigE interface requires that the data source must be designed to encapsulate data streams in a format compatible with the Mark 5C requirements. However, in the interest of backward compatibility, the Mark 5C will also support writing the disk modules in Mark 5B format to enable correlation on the existing Mark 4 hardware correlators, although only at 2048 Mbps.
Author
VERY LONG BASE INTERFEROMETRY; ANTENNA DESIGN; DATA SYSTEMS; DATA RECORDING; DATA FLOW ANALYSIS; CORRELATORS; COMPUTER SYSTEMS PROGRAMS
20090034057 Observatoire de Paris, France
Paris Observatory Analysis Center OPAR: Report on Activities, January - December 2008
Gontier, Anne-Marie; Lambert, Sebastien B.; Barache, Christophe; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 291-29; In English; Original contains black and white illustrations
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We report on activities of the Paris Observatory VLBI analysis center (OPAR) for calendar year 2008. Among the main issues is the inclusion of OPAR solutions in the IVS rapid solution. We also summarize various scientific results concerning the stabilization of the celestial reference frame, the determination of the dissipative factor associated with the Earth s fluid core by the use of VLBI and superconducting gravimeters, improvements in the theory of nutation and precession, and the determination of the relativistic parameter gamma from VLBI delays.
Author
VERY LONG BASE INTERFEROMETRY; CELESTIAL REFERENCE SYSTEMS; OBSERVATORIES; GRAVIMETERS; EARTH CORE; SUPERCONDUCTIVITY
20090034058 Central Astronomical Observatory, Pulkovo, Russian Federation
Pulkovo IVS Analysis Center (PUL) 2008 Report
Malkin, Zinovy; Miller, Natalia; Sokolova, Julia; Popova, Elena; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 299-30; In English
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This report briefly presents the PUL IVS Analysis Center activities during 2008 and plans for the coming year. The main topics of investigations in that period were comparison and combination of catalogs of radio source positions, analysis of VLBI Earth Orientation Parameters (EOP) series, analysis of radio source position and zenith troposphere delay time series.
Author
EARTH ORIENTATION; VERY LONG BASE INTERFEROMETRY; GEODESY; TIME SERIES ANALYSIS
20090034059 National Inst. of Information and Communications Technology, Japan
Technology Development Center at NICT
Takefuji, Kazuhiro; Ichikawa, Ryuichi; Sekido, Mamoru; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 325-32; In English; Original contains color and black and white illustrations
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National Institute of Information and Communications Technology (NICT) has led the development of the VLBI technique and has been maintaining a high level of activity in both observations and technical developments. This report gives a review of the Technology Development Center (TDC) at NICT and summarizes its recent activities.
Author
VERY LONG BASE INTERFEROMETRY; DATA ACQUISITION; INFORMATION SYSTEMS; DISTRIBUTED PROCESSING; AUTOCORRELATION; DATA BASES
20090034060 Onsala Space Observatory, Sweden
Onsala Space Observatory - IVS Technology Development Center
Haas, Ruediger; Helldner, Leif; Pantaleev, Miroslav; Loefgren, Johan; Elgered, Gunnar; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 329-33; In English; Original contains color illustrations
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This report summarizes the technical development related to the geodetic VLBI activities that were performed at the Onsala Space Observatory during 2008. Most of the tasks planned for the year were addressed, and some new tasks were initiated. The focus was on: (1) tests of an analog fiber link for the transfer of VLBI IF-signals, (2) a contribution to the project to develop a dual-polarized broadband Eleven feed for VLBI2010, (3) the superconducting gravimeter, and (4) the development of a GNSS-based tide gauge.
Author
VERY LONG BASE INTERFEROMETRY; SUPERCONDUCTIVITY; MEASURING INSTRUMENTS; AEROSPACE ENGINEERING; BROADBAND; GRAVIMETERS; GEODESY
20090034061 Bordeaux Univ., France
Bordeaux Observatory Analysis Center Report
Charlot, Patrick; Bellanger, Antoine; Bourda, Geraldine; Colioud, Arnaud; Zhang, Ming; Baudry, Alain; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 246-24; In English; Original contains black and white illustrations
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This report summarizes the activities of the Bordeaux Observatory Analysis Center in 2008. During this period, we continued our VLBI imaging activity and produced a total of 581 VLBI maps by processing three RDV sessions. Structure indices and source compactness were derived from these images to assess the astrometric source quality. A pipeline is also being developed to model-fit the VLBI structures in an automatic way and extract relevant physical information for astrophysics. Other activities focused on regular analysis of the IVS-R1 and IVS-R4 sessions and simulations to study the imaging capabilities of the next generation VLBI system. On the observational side, we further pursued our project to identify new reference frame sources for the link with the future Gaia frame, and we imaged 105 weak candidate sources for this link. Plans for 2009 follow the same analysis and research lines.
Author
VERY LONG BASE INTERFEROMETRY; ASTROMETRY; EXTRACTION; OBSERVATORIES; ASTROPHYSICS
20090034062 Academia Sinica, Shanghai, China
Sheshan VLBI Station Report for 2008
Hong, Xiaoyu; Fan, Qingyuan; An, Tao; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 150-15; In English; Original contains color illustrations
Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034062
This report summarizes the observing activities at the Sheshan station (SESHAN25) in 2008. The Sheshan radio telescope participated in nineteen 24-hour VLBI sessions organized by the IVS and in thirty-seven traditional VLBI experiments, as well as in a number of e-VLBI sessions and formatter tests organized by the EVN. Apart from the international VLBI activities, the telescope was involved in 125 monitoring experiments of the Chinese Chang E-1 lunar satellite, and in nine observations of the Japanese SELENE lunar satellite. We also report on updates to and development of the facilities at the station.
Author
VERY LONG BASE INTERFEROMETRY; LUNAR SATELLITES; RADIO TELESCOPES; SATELLITE OBSERVATION
20090034063 Norwegian Defence Research Establishment, Kjeller, Norway
FFI Analysis Center
Andersen, Per Helge; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 259-26; In English
Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034063
FFI s contribution to the IVS as an analysis center focuses primarily on a combined analysis at the observation level of data from VLBI, GPS and SLR using the GEOSAT software. This report shortly summarises the current status of analyses performed with the GEOSAT software. FFI is currently an Analysis Center for IVS and ILRS, a Technology Development Center for IVS, and a Combination Research Center for IERS.
Author
VERY LONG BASE INTERFEROMETRY; GLOBAL POSITIONING SYSTEM; GEOSAT SATELLITES; MATHEMATICAL MODELS; PARAMETER IDENTIFICATION; METEOROLOGICAL PARAMETERS; CORRELATION; EARTH ORIENTATION; GEODESY; GEOPHYSICS
20090034064 NASA Goddard Space Flight Center, Greenbelt, MD, United States
GSFC VLBI Analysis Center
Gordon, David; Ma, Chopo; MacMillan, Dan; Gipson, John; Baver, Karen; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 265-26; In English
Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034064
This report presents the activities of the GSFC VLBI Analysis Center during 2008. The GSFC Analysis Center analyzes all IVS sessions, makes regular IVS submissions of data and analysis products, and performs research and software development aimed at improving the VLBI technique. 1. Introduction The GSFC VLBI Analysis Center is located at NASA s Goddard Space Flight Center in Green- belt, Maryland. It is part of a larger VLBI group which also includes the IVS Coordinating Center, the CORE Operation Center, a Technology Development Center, and a Network Station. The Analysis Center participates in all phases of geodetic and astrometric VLBI analysis, software development, and research aimed at improving the VLBI technique.
Author
VERY LONG BASE INTERFEROMETRY; SOFTWARE ENGINEERING; GEODESY; ASTROMETRY
20090034065 NASA Goddard Space Flight Center, Greenbelt, MD, United States
Goddard Geophysical and Astronomical Observatory
Rdmond, Jay; Diegel, Irv; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 103-10; In English; Original contains color and black and white illustrations
Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034065
This report summarizes the technical parameters and the technical staff of the VLBI system at the fundamental station GGAO. It also gives an overview about the VLBI activities during the previous year. The outlook lists the outstanding tasks to improve the performance of GGAO. 1. GGAO at Goddard The Goddard Geophysical and Astronomical Observatory (GGAO) consists of a radio telescope for VLBI, an SLR site to include MOBLAS-7, SLR-2000 (development system), a 48" telescope for developmental two color Satellite Ranging, a GPS timing and development lab, meteorological sensors, and an H-maser. In addition, we are a fiducial IGS site with several IGS/IGSX receivers.
Author
TIME MEASUREMENT; RADIO TELESCOPES; METEOROLOGICAL INSTRUMENTS; GLOBAL POSITIONING SYSTEM; GEOPHYSICAL OBSERVATORIES; ASTRONOMICAL OBSERVATORIES; VERY LONG BASE INTERFEROMETRY
20090034066 Saint Petersburg Univ., Saint Petersburg, Russian Federation
Analysis Center of Saint Petersburg University
Vityazev, Veniamin; Trofimov, Dmitriy; Kudryashova, Maria; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 241-24; In English
Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034066
This report briefly summarizes the activities of the Analysis Center of Saint Petersburg University during 2008. Changes which happened in our solutions and staff, as well as our future plans, are described. 1. Introduction The Sobolev Astronomical Institute is located in Petrodvorets, near Saint Petersburg. It is a research institute of the Saint Petersburg State University. In 1998 the Analysis Center of Saint Petersburg University was established in the Institute. Due to the staff changes in 2007 we had a gap in our submissions for IVS that year. The main activity of the SPU AC for the International VLBI Service before 2007 consisted of routine processing of 24-hour and 1-hour observational sessions for obtaining Earth Orientation Parameters (EOP) and rapid UT1-UTC values respectively. In 2008 we resumed submitting results of 24-hour session processing. During 2008 the activities of the SPU AC were supported by the Ministry of Education and Science of the Russian Federation (grant 2.1.1.5077).
Author
ASTRONOMY; VERY LONG BASE INTERFEROMETRY; ALTERNATING CURRENT; EARTH ORIENTATION
20090034067 Academy of Sciences (Russia), Saint Petersburg, Russian Federation
Svetloe Radio Astronomical Observatory
Smolentsev, Sergey; Rahimov, Ismail; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 158-16; In English; Original contains black and white illustrations
Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034067
This report summarizes information on recent activities at the Svetloe Radio Astronomical Observatory (SvRAO). During the previous year a number of changes were carried out at the observatory to improve some technical parameters and upgrade some units to required status. The report provides also an overview of current geodetic VLBI activities and gives an outlook for the next year.
Author
VERY LONG BASE INTERFEROMETRY; GEODESY; ASTRONOMICAL OBSERVATORIES
20090034068 National Inst. of Polar Research, Tokyo, Japan
JARE Syowa Station 11-m Antenna, Antarctica
Doi, Koichiro; Shibuya, Kazuo; Aoyama, Yuichi; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 161-16; In English; Original contains color illustrations
Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034068
The operation of the 11-m S/X-band antenna at Syowa Station (69.0.S, 39.6.E) by the Japanese Antarctic Research Expeditions (JAREs) started in February 1998 and continues until today (January 2009). A cumulative total of 83 quasi-regular geodetic VLBI experiments were observed by the end of 2008. Syowa Station will participate in six OHIG sessions in 2009. The data from six OHIG sessions in 2008 were recorded on hard disks through the K5 terminal. They will be brought back from Syowa Station to Japan in April 2009. The data from the OHIG51 through the OHIG57 sessions observed by JARE48 and JARE49 have been transferred to the Bonn Correlator directly by way of one of NICT's servers. Analysis results obtained from the data until the OHIG56 session indicate that the length of the Syowa-Hobart baseline is increasing with a rate of 54.7 +/-0.4 mm/yr and that the length of the Syowa-HartRAO baseline is increasing with a rate of 11.7+/- 0.3 mm/yr. The length of the Syowa-O'Higgins baseline is slightly increasing with a rate of 1.7+/-0.9 mm/yr.
Author
MICROWAVE ANTENNAS; SUPERHIGH FREQUENCIES; VERY LONG BASE INTERFEROMETRY; ULTRAHIGH FREQUENCIES; GEODESY; CORRELATORS
20090034069 National Inst. of Information and Communications Technology, Ibaraki, Japan
Data Center at NICT
Koyama, Yasuhiro; Sekido, Mamoru; Takiguchi, Hiroshi; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 232-23; In English; Original contains color illustrations
Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034069
The Data Center at National Institute of Information and Communications Technology (NICT) archives and releases the databases and analysis results processed at the Correlation Center and the Analysis Center at NICT. Regular VLBI sessions with the Key Stone Project VLBI Network were the primary objective of the Data Center. These regular sessions continued until the end of November 2001. In addition to the Key Stone Project VLBI sessions, NICT has been conducting geodetic VLBI sessions for various purposes, and these data are also archived and released by the Data Center.
Author
VERY LONG BASE INTERFEROMETRY; CORRELATION; GEODESY
20090034070 National Inst. of Information and Communications Technology, Ibaraki, Japan
VLBI Correlators in Kashima
Sekido, Mamoru; Kimura, Moritaka; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 212-21; In English; Original contains black and white illustrations
Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034070
Software correlator systems developed at Kashima Space Research Center are used for data processing of R&D VLBI experiments. Major correlation tasks processed in 2008 were the following three: e-VLBI project for rapid UT1 measurement, CARAVAN2400 project for reference baseline determination with small diameter antennas, and a project for time standards comparison with VLBI. An automatic data processing scheme, which distributes correlation tasks to a cluster of PCs for parallel processing, has been extensively used for this geodetic VLBI processing.
Author
DATA PROCESSING; GEODESY; PARALLEL PROCESSING (COMPUTERS); SOFTWARE ENGINEERING; VERY LONG BASE INTERFEROMETRY; CORRELATORS
20090034071 Academy of Sciences (Russia), Saint Petersburg, Russian Federation
IAA Correlator Center
Surkis, Igor; Fateev, Artemy; Melnikov, Alexey; Mishin, Vladimir; Shantyr, Violet; Zimovsky, Vladimir; International VLBI Service for Geodesy and Astrometry 2008 Annual Report; August 2009; pp. 209-21; In English; Original contains color illustrations
Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034071
The prototype correlator of ARC was produced. It is a 2-station VSI-H XF-type hardware VLBI correlator connected to two Mark 5B terminals. The fullscale 6-station VLBI correlator ARC is scheduled next and will be constructed soon. The VLBI data of the 3-station sessions of the Russian national network Quasar was processed using the MicroPARSEC correlator. The IAA Correlator Center is located and staffed by the Institute of Applied Astronomy in St.-Petersburg, Russia. The IAA Correlator Center is devoted to processing geodetic, astrometric, and astrophysical observations made with the Russian national VLBI network Quasar.
Author
ASTROMETRY; GEODETIC SURVEYS; QUASARS; VERY LONG BASE INTERFEROMETRY; ASTROPHYSICS; CORRELATORS
Additions to the NASA Aeronautics and Space Database as of 10/12/2009
20090034082 Commonwealth Scientific and Industrial Research Organization, Linfield, Australia
Development and Evaluation of Sensor Concepts for Ageless Aerospace Vehicles: Report 5 - Phase 2 Implementation of the Concept Demonstrator
Batten, Adam; Dunlop, John; Edwards, Graeme; Farmer, Tony; Gaffney, Bruce; Hedley, Mark; Hoschke, Nigel; Isaacs, Peter; Johnson, Mark; Lewis, Chris; Murdoch, Alex; Poulton, Geoff; Price, Don; Prokopenko, Mikhail; Sharp, Ian; Scott, Andrew; Valencia, Philip; Wang, Peter; Whitnall, Denis; September 2009; In English; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 939904.05.07
Report No.(s): NASA/CR-2009-215931; LF99-7916; L-71308D; TIPP 2056; Copyright; Avail.: CASI: A04, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034082
This report describes the second phase of the implementation of the Concept Demonstrator experimental test-bed system containing sensors and processing hardware distributed throughout the structure, which uses multi-agent algorithms to characterize impacts and determine a suitable response to these impacts. This report expands and adds to the report of the first phase implementation. The current status of the system hardware is that all 192 physical cells (32 on each of the 6 hexagonal prism faces) have been constructed, although only four of these presently contain data-acquisition sub-modules to allow them to acquire sensor data. Impact detection.. location and severity have been successfully demonstrated. The software modules for simulating cells and controlling the test-bed are fully operational. although additional functionality will be added over time. The visualization workstation displays additional diagnostic information about the array of cells (both real and simulated) and additional damage information. Local agent algorithms have been developed that demonstrate emergent behavior of the complex multi-agent system, through the formation of impact damage boundaries and impact networks. The system has been shown to operate well for multiple impacts. and to demonstrate robust reconfiguration in the presence of damage to numbers of cells.
Author
ALGORITHMS; DATA ACQUISITION; TEST STANDS; MODULES; IMPACT DAMAGE; DISPLAY DEVICES; COMPUTER PROGRAMS; COMPLEX SYSTEMS; PROVING
20090034083 NASA Langley Research Center, Hampton, VA, United States
Some Exact Results for the Schroedinger Wave Equation with a Time Dependent Potential
Campbell, Joel; [2009]; In English
Contract(s)/Grant(s): WBS 129985.05.07.98.42.0
Report No.(s): LF99-8541; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034083
The time dependent Schroedinger equation with a time dependent delta function potential is solved exactly for many special cases. In all other cases the problem can be reduced to an integral equation of the Volterra type. It is shown that by knowing the wave function at the origin, one may derive the wave function everywhere. Thus, the problem is reduced from a PDE in two variables to an integral equation in one. These results are used to compare adiabatic versus sudden changes in the potential. It is shown that adiabatic changes in the p otential lead to conservation of the normalization of the probability density.
Author
SCHROEDINGER EQUATION; TIME DEPENDENCE; INTEGRAL EQUATIONS; PROBABILITY THEORY; DELTA FUNCTION; WAVE FUNCTIONS
20090034086 NASA Dryden Flight Research Center, Edwards, CA, United States
Further Development of Ko Displacement Theory for Deformed Shape Predictions of Nonuniform Aerospace Structures
Ko, William L.; Fleischer, Van Tran; September 2009; In English; Original contains black and white illustrations
Report No.(s): NASA/TP-2009-214643; H-2889; DFRC-781; No Copyright; Avail.: CASI: A05, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034086
The Ko displacement theory previously formulated for deformed shape predictions of nonuniform beam structures is further developed mathematically. The further-developed displacement equations are expressed explicitly in terms of geometrical parameters of the beam and bending strains at equally spaced strain-sensing stations along the multiplexed fiber-optic sensor line installed on the bottom surface of the beam. The bending strain data can then be input into the displacement equations for calculations of local slopes, deflections, and cross-sectional twist angles for generating the overall deformed shapes of the nonuniform beam. The further-developed displacement theory can also be applied to the deformed shape predictions of nonuniform two-point supported beams, nonuniform panels, nonuniform aircraft wings and fuselages, and so forth. The high degree of accuracy of the further-developed displacement theory for nonuniform beams is validated by finite-element analysis of various nonuniform beam structures. Such structures include tapered tubular beams, depth-tapered unswept and swept wing boxes, width-tapered wing boxes, and double-tapered wing boxes, all under combined bending and torsional loads. The Ko displacement theory, combined with the fiber-optic strain-sensing system, provide a powerful tool for in-flight deformed shape monitoring of unmanned aerospace vehicles by ground-based pilots to maintain safe flights.
Author
SLOPES; DISPLACEMENT; DEFORMATION; BEAMS (SUPPORTS); STRUCTURAL ENGINEERING; IN-FLIGHT MONITORING; FINITE ELEMENT METHOD
20090034149 NASA Langley Research Center, Hampton, VA, United States
Technology Challenges and Opportunities for Very Large In-Space Structural Systems
Belvin, W. Keith; Dorsey, John T.; Watson, Judith J.; September 08, 2009; In English; International Symposium on Solar Energy from Space,, 8-10 Sep. 2009, Toronto, Canada; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 736466.11.01.07.43.24.01
Report No.(s): LF99-9135; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034149
Space solar power satellites and other large space systems will require creative and innovative concepts in order to achieve economically viable designs. The mass and volume constraints of current and planned launch vehicles necessitate highly efficient structural systems be developed. In addition, modularity and in-space deployment/construction will be enabling design attributes. While current space systems allocate nearly 20 percent of the mass to the primary structure, the very large space systems of the future must overcome subsystem mass allocations by achieving a level of functional integration not yet realized. A proposed building block approach with two phases is presented to achieve near-term solar power satellite risk reduction with accompanying long-term technology advances. This paper reviews the current challenges of launching and building very large space systems from a structures and materials perspective utilizing recent experience. Promising technology advances anticipated in the coming decades in modularity, material systems, structural concepts, and in-space operations are presented. It is shown that, together, the current challenges and future advances in very large in-space structural systems may provide the technology pull/push necessary to make solar power satellite systems more technically and economically feasible.
Author
AEROSPACE SYSTEMS; ARTIFICIAL SATELLITES; LARGE SPACE STRUCTURES; SOLAR POWER SATELLITES; TECHNOLOGY UTILIZATION
20090034155 NASA Johnson Space Center, Houston, TX, United States
Using the Enhanced Daily Load Stimulus Model to Quantify the Mechanical Load and Bone Mineral Density Changes Experienced by Crew Members on the International Space Station
Genc, K. O.; Gopalakrishnan, R.; Kuklis, M. M.; Maender, C. C.; Rice, A. J.; Cavanagh, P. R.; [2009]; In English; Orthopadeic Research Society 56th Annual Meeting, 6-9 Mar. 2010, New Orleans, LA, United States; Original contains color illustrations
Contract(s)/Grant(s): NCC9-153
Report No.(s): JSC-CN-18837; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034155
Despite the use of exercise countermeasures during long-duration space missions, bone mineral density (BMD) and predicted bone strength of astronauts continue to show decreases in the lower extremities and spine. This site-specific bone adaptation is most likely caused by the effects of microgravity on the mechanical loading environment of the crew member. There is, therefore, a need to quantify the mechanical loading experienced on Earth and on-orbit to define the effect of a given "dose" of loading on bone homeostasis. Gene et al. recently proposed an enhanced DLS (EDLS) model that, when used with entire days of in-shoe forces, takes into account recently developed theories on the importance of factors such as saturation, recovery, and standing and their effects on the osteogenic response of bone to daily physical activity. This algorithm can also quantify the tinting and type of activity (sit/unload, stand, walk, run or other loaded activity) performed throughout the day. The purpose of the current study was to use in-shoe force measurements from entire typical work days on Earth and on-orbit in order to quantify the type and amount of loading experienced by crew members. The specific aim was to use these measurements as inputs into the EDLS model to determine activity timing/type and the mechanical "dose" imparted on the musculoskeletal system of crew members and relate this dose to changes in bone homeostasis.
Derived from text
BONE MINERAL CONTENT; FLIGHT CREWS; INTERNATIONAL SPACE STATION; LOADS (FORCES); LONG DURATION SPACE FLIGHT; MICROGRAVITY; MUSCULOSKELETAL SYSTEM
20090034157 NASA Johnson Space Center, Houston, TX, United States
Blue Marble Matches: Using Earth for Planetary Comparisons
Graff, Paige Valderrama; September 26, 2009; In English; Original contains color and black and white illustrations
Contract(s)/Grant(s): NNJ05HI05C
Report No.(s): JSC-CN-18912; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034157
Goal: This activity is designed to introduce students to geologic processes on Earth and model how scientists use Earth to gain a better understanding of other planetary bodies in the solar system. Objectives: Students will: 1. Identify common descriptor characteristics used by scientists to describe geologic features in images. 2. Identify geologic features and how they form on Earth. 3. Create a list of defining/distinguishing characteristics of geologic features 4. Identify geologic features in images of other planetary bodies. 5. List observations and interpretations about planetary body comparisons. 6. Create summary statements about planetary body comparisons.
Author
PLANETS; STRUCTURAL PROPERTIES (GEOLOGY); STUDENTS; SOLAR SYSTEM; EARTH (PLANET)
20090034160 NASA Dryden Flight Research Center, Edwards, CA, United States
First Stage of a Highly Reliable Reusable Launch System
Kloesel, Kurt J.; Pickrel, Jonathan B.; Sayles, Emily L.; Wright, Michael; Marriott, Darin; Holland, Leo; Kuznetsov, Stephen; September 14, 2009; In English; AIAA SPACE 2009 Conference and Exposition, 14-17 Sep. 2009, Pasadena, CA, United States; Original contains color and black and white illustrations
Report No.(s): DFRC-950; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034160
Electromagnetic launch assist has the potential to provide a highly reliable reusable first stage to a space access system infrastructure at a lower overall cost. This paper explores the benefits of a smaller system that adds the advantages of a high specific impulse air-breathing stage and supersonic launch speeds. The method of virtual specific impulse is introduced as a tool to emphasize the gains afforded by launch assist. Analysis shows launch assist can provide a 278-s virtual specific impulse for a first-stage solid rocket. Additional trajectory analysis demonstrates that a system composed of a launch-assisted first-stage ramjet plus a bipropellant second stage can provide a 48-percent gross lift-off weight reduction versus an all-rocket system. The combination of high-speed linear induction motors and ramjets is identified, as the enabling technologies and benchtop prototypes are investigated. The high-speed response of a standard 60 Hz linear induction motor was tested with a pulse width modulated variable frequency drive to 150 Hz using a 10-lb load, achieving 150 mph. A 300-Hz stator-compensated linear induction motor was constructed and static-tested to 1900 lbf average. A matching ramjet design was developed for use on the 300-Hz linear induction motor.
Author
REUSABLE LAUNCH VEHICLES; HIGH IMPULSE; SUPERSONIC SPEED; SPECIFIC IMPULSE; RAMJET ENGINES; INDUCTION MOTORS; TRAJECTORY ANALYSIS; WEIGHT REDUCTION
20090034163 NASA Langley Research Center, Hampton, VA, United States
Developments to Increase the Performance, Operational Versatility and Automation of a Lunar Surface Manipulation System
Dorsey, John T.; Jones, Thomas C.; Doggett, William R.; Roithmayr, Carlos M.; King, Bruce D.; Mikulas, Marting M.; September 14, 2009; In English; AIAA Space 2009 Conference and Exposition, 14-17 Sep. 2009, Pasadena, CA, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 431731.04.02.04
Report No.(s): LF99-8273; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034163
The objective of this paper is to describe and summarize the results of the development efforts for the Lunar Surface Manipulation System (LSMS) with respect to increasing the performance, operational versatility, and automation. Three primary areas of development are covered, including; the expansion of the operational envelope and versatility of the current LSMS test-bed, the design of a second generation LSMS, and the development of automation and remote control capability. The first generation LSMS, which has been designed, built, and tested both in lab and field settings, is shown to have increased range of motion and operational versatility. Features such as fork lift mode, side grappling of payloads, digging and positioning of lunar regolith, and a variety of special end effectors are described. LSMS operational viability depends on bei nagble to reposition its base from an initial position on the lander to a mobility chassis or fixed locations around the lunar outpost. Preliminary concepts are presented for the second generation LSMS design, which will perform this self-offload capability. Incorporating design improvements, the second generation will have longer reach and three times the payload capability, yet it will have approximately equivalent mass to the first generation. Lastly, this paper covers improvements being made to the control system of the LSMS test-bed, which is currently operated using joint velocity control with visual cues. These improvements include joint angle sensors, inverse kinematics, and automated controls.
Author
AUTOMATIC CONTROL; LUNAR BASES; REMOTE CONTROL; LUNAR SURFACE; LUNAR ROCKS; PAYLOADS; REGOLITH; CONTROLLABILITY
20090034165 NASA Langley Research Center, Hampton, VA, United States
OLTARIS: On-Line Tool for the Assessment of Radiation in Space
Singleterry, Robert C., Jr.; Blattnig, Steve R.; Clowdsley, Martha S.; Qualls, Garry D.; Sandridge, Chris A.; Simonsen, Lisa C.; Norbury, John W.; Slaba, Tony C.; Walker, Steve A.; Badavi, Francis F.; Spangler, Jan L.; Aumann, Aric R.; Zapp, E. Neal; Rutledge, Robert D.; Lee, Kerry T.; Norman, Ryan B.; September 14, 2009; In English; AIAA Space 2009 Conference and Exposition, 14-17 Sep. 2009, Pasadena, CA, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 651549.02.07.01
Report No.(s): LF99-8387; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034165
The On-Line Tool for the Assessment of Radiation In Space (OLTARIS) is a World Wide Web based tool that assesses the effects of space radiation to humans in items such as spacecraft, habitats, rovers, and spacesuits. This document explains the basis behind the interface and framework used to input the data, perform the assessment, and output the results to the user as well as the physics, engineering, and computer science used to develop OLTARIS. The physics is based on the HZETRN2005 and NUCFRG2 research codes. The OLTARIS website is the successor to the SIREST website from the early 2000 s. Modifications have been made to the code to enable easy maintenance, additions, and configuration management along with a more modern web interface. Over all, the code has been verified, tested, and modified to enable faster and more accurate assessments. The next major areas of modification are more accurate transport algorithms, better uncertainty estimates, and electronic response functions. Improvements in the existing algorithms and data occur continuously and are logged in the change log section of the website.
Author
EXTRATERRESTRIAL RADIATION; ON-LINE SYSTEMS; SPACE TOOLS; CONFIGURATION MANAGEMENT; HABITATS
20090034167 Boeing Co., Huntington Beach, CA, United States
Damage Arresting Composites for Shaped Vehicles
Velicki, Alex; September 2009; In English; Original contains color and black and white illustrations
Contract(s)/Grant(s): NNL07AA48CWBS 561581.02.08.07.15.03; 4200208122
Report No.(s): NASA/CR-2009-215932; LF99-8391; Copyright; Avail.: CASI: A05, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034167
This report describes the development of a novel structural solution that addresses the demanding fuselage loading requirements for the Hybrid Wing or Blended Wing Body configurations that are described in NASA NRA subtopic A2A.3, "Materials and Structures for Wing Components and Non-Circular Fuselage." The phase I portion of this task includes a comprehensive finite element model-based structural sizing exercise performed using the BWB airplane configuration to generate internal loads and fuselage panel weights for an advanced Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) structural concept. An accompanying element-level test program is also described which substantiates the analytical results and calculation methods used in the trade study. The phase II plan for the continuation of this research is also included herein.
Author
BLENDED-WING-BODY CONFIGURATIONS; AERODYNAMIC CONFIGURATIONS; FUSELAGES; PULTRUSION; LOADS (FORCES); DAMAGE
20090034168 NASA Langley Research Center, Hampton, VA, United States
Modeling and Simulation of the Second-Generation Orion Crew Module Air Bag Landing System
Timmers, Richard B.; Hardy, Robin C.; Willey, Cliff E.; Welch, Joseph V.; September 14, 2009; In English; AIAA Space 2009 Conference and Exposition, 14-17 Sep. 2009, Pasadena, CA, United States; Original contains black and white illustrations
Report No.(s): LF99-9199; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034168
Air bags were evaluated as the landing attenuation system for earth landing of the Orion Crew Module (CM). Analysis conducted to date shows that airbags are capable of providing a graceful landing of the CM in nominal and off-nominal conditions such as parachute failure, high horizontal winds, and unfavorable vehicle/ground angle combinations, while meeting crew and vehicle safety requirements. The analyses and associated testing presented here surround a second generation of the airbag design developed by ILC Dover, building off of relevant first-generation design, analysis, and testing efforts. In order to fully evaluate the second generation air bag design and correlate the dynamic simulations, a series of drop tests were carried out at NASA Langley s Landing and Impact Research (LandIR) facility in Hampton, Virginia. The tests consisted of a full-scale set of air bags attached to a full-scale test article representing the Orion Crew Module. The techniques used to collect experimental data, develop the simulations, and make comparisons to experimental data are discussed.
Author
DROP TESTS; SPACECRAFT MODULES; LANDING LOADS; LANDING AIDS; FULL SCALE TESTS; DESIGN ANALYSIS; SAFETY FACTORS; IMPACT LOADS
20090034169 NASA Langley Research Center, Hampton, VA, United States
Electrical Characterizations of Lightning Strike Protection Techniques for Composite Materials
Szatkowski, George N.; Nguyen, Truong X.; Koppen, Sandra V.; Ely, Jay J.; Mielnik, John J.; September 15, 2009; In English; International Conference on Lightning and Static Electricity, 15-17 Sep. 2009, Pittsboro, MA, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 645846.02.07.07.12.02
Report No.(s): LF99-9437; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034169
The growing application of composite materials in commercial aircraft manufacturing has significantly increased the risk of aircraft damage from lightning strikes. Composite aircraft designs require new mitigation strategies and engineering practices to maintain the same level of safety and protection as achieved by conductive aluminum skinned aircraft. Researchers working under the NASA Aviation Safety Program s Integrated Vehicle Health Management (IVHM) Project are investigating lightning damage on composite materials to support the development of new mitigation, diagnosis & prognosis techniques to overcome the increased challenges associated with lightning protection on composite aircraft. This paper provides an overview of the electrical characterizations being performed to support IVHM lightning damage diagnosis research on composite materials at the NASA Langley Research Center.
Author
COMPOSITE MATERIALS; AIRCRAFT STRUCTURES; LIGHTNING; FLIGHT SAFETY; RISK; PROTECTION; COMPOSITE STRUCTURES; DAMAGE; DIAGNOSIS
20090034177 NASA Goddard Space Flight Center, Greenbelt, MD, United States
Design Aspects of the VLBI2010 System - Progress Report of the IVS VLBI2010 Committee
Petrachenko, Bill; Niell, Arthur; Behrend, Dirk; Corey, Brian; Boehm, Johannes; Chralot, Patrick; Collioud, Arnaud; Gipson, John; Haas, Ruediger; Hobiger, Thomas; Koyama, Yasuhiro; MacMillan, Dan; Malkin, Zinvoy; Nilsson, Tobias; Pany, Andrea; Tuccari, Gino; Whitney, Alan; Wresnik, Joerg; June 2009; In English; Original contains color and black and white illustrations
Contract(s)/Grant(s): NNG05HY04CP18404-N10
Report No.(s): NASA/TM-2009-214180; 200901964; Copyright; Avail.: CASI: A04, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034177
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.
Author
VERY LONG BASE INTERFEROMETRY; GEODESY; ASTROMETRY; DIGITAL SYSTEMS; CALIBRATING; FREQUENCIES; PROVING; CORRELATORS
20090034179 NASA Marshall Space Flight Center, Huntsville, AL, United States
Evaluation of an Interferometric Sensor for In-Space Detection of Gas Leaks
Polzin, Kurt A.; Korman, Valentin; Sinko, John; Hendrickson, Adam; August 02, 2009; In English; 45th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, 2-5 Aug. 2009, Denver, CO, United States; Original contains black and white illustrations
Report No.(s): M09-0240; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034179
Space mission planning often involves long-term storage of volatile liquids or high-pressure gases. These may include cryogenic fuels and oxidizers, high-pressure gases, and life-support-critical consumables. The risk associated with the storage of fluids and gases in space systems has long been an issue and the ability to retain these fluids is often tied to mission success. A leak in the storage or distribution system can cause many different problems, including a simple, but mission endangering, loss of inventory or, in severe cases, unbalanced thrust loads on a flight vehicle. Cryogenic propellants are especially difficult to store, especially over a long duration. The propellant can boil off and be lost through the insulating walls of the tank or simple thermal cycling of the fittings, valves, and propellant feed lines may unseat seals allowing the fluid to escape. Current NASA missions call for long-duration in-space storage of propellants, oxidizers, and life support supplies. Leaks of a scale detectable through a pressure drop in the storage tank are often catastrophic and have long been the focus of ground-based mitigation efforts where redundant systems are often employed. However, there is presently no technology available for detecting and monitoring low-level, but still mission-endangering, gas leaks in space. Standard in-space gas detection methods either have a very limited pressure range over which they operate effectively or are limited to certain gases. Mass spectrometer systems are able to perform the detection tasks, but their size, mass and use of high voltage, which could potentially lead to an arc that ignites a combustible propellent, severely limit their usefulness in a space system. In this paper, we present results from testing of the light-based interferometric gas monitoring and leak detection sensor shown in Fig. 1. The output of the sensor is an interference fringe pattern that is a function of the gas density, and commensurate index of refraction, in the sample region. Changes in the density of gas cause the interference fringes to move across a photodiode detector, providing a temporal history of the leak. The sensor is fiber coupled and constructed from solid optics, allowing for placement almost anywhere on the spacecraft. It is also advantageous in that it consumes very little power and does not introduce an ignition source. Data are presented demonstrating the capability of the sensor to measure density variations in different gas species. In addition, the transient response of the sensor in vacuum is demonstrated. These data extend and improve upon the results previously presented by the authors in Ref. [1].
Author
DETECTION; GAS DETECTORS; INTERFEROMETRY; LEAKAGE; PROPELLANT STORAGE
Additions to the NASA Aeronautics and Space Database as of 10/13/2009
20090034232 United Space Alliance, Houston, TX, United States
21st Century Extravehicular Activities: Synergizing Past and Present Training Methods for Future Spacewalking Success
Moore, Sandra K.; Gast, Matthew A.; [2009]; In English; 60th International Astronautical Congress, 12-16 Nov. 2009, Daejeon, Korea, Republic of; Original contains color illustrations
Report No.(s): IAC-09.B6.3.6; JSC-CN-18915; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034232
Neil Armstrong's understated words, "That's one small step for man, one giant leap for mankind." were spoken from Tranquility Base forty years ago. Even today, those words resonate in the ears of millions, including many who had yet to be born when man first landed on the surface of the moon. By their very nature, and in the the spirit of exploration, extravehicular activities (EVAs) have generated much excitement throughout the history of manned spaceflight. From Ed White's first space walk in June of 1965, to the first steps on the moon in 1969, to the expected completion of the International Space Station (ISS), the ability to exist, live and work in the vacuum of space has stood as a beacon of what is possible. It was NASA's first spacewalk that taught engineers on the ground the valuable lesson that successful spacewalking requires a unique set of learned skills. That lesson sparked extensive efforts to develop and define the training requirements necessary to ensure success. As focus shifted from orbital activities to lunar surface activities, the required skill-set and subsequently the training methods, changed. The requirements duly changed again when NASA left the moon for the last time in 1972 and have continued to evolve through the Skylab, Space Shuttle; and ISS eras. Yet because the visits to the moon were so long ago, NASA's expertise in the realm of extra-terrestrial EVAs has diminished. As manned spaceflight again shifts its focus beyond low earth orbit, EVA success will depend on the ability to synergize the knowledge gained over 40+ years of spacewalking to create a training method that allows a single crewmember to perform equally well, whether performing an EVA on the surface of the Moon, while in the vacuum of space, or heading for a rendezvous with Mars. This paper reviews NASA's past and present EVA training methods and extrapolates techniques from both to construct the basis for future EVA astronaut training.
Author
ASTRONAUT TRAINING; EXTRAVEHICULAR ACTIVITY; INTERNATIONAL SPACE STATION; SPACE SHUTTLES; NASA SPACE PROGRAMS; MANNED SPACE FLIGHT
20090034233 United Space Alliance, Houston, TX, United States
A Glimpse from the Inside of a Space Suit: What Is It Really Like to Train for an EVA?
Gast, Matthew A.; Moore, Sandra K.; [2009]; In English; 60th International Astronautical Congress, 10-16 Oct. 2009, Daejeon, Korea, Republic of; Original contains color illustrations
Report No.(s): IAC-09.B6.3.6; JSC-CN-18933; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034233
The beauty of the view from the office of a spacewalking astronaut gives the impression of simplicity, but few beyond the astronauts, and those who train them, know what it really takes to get there. Extravehicular Activity (EVA) training is an intense process that utilizes NASA's Neutral Buoyancy Laboratory (NBL) to develop a very specific skill set needed to safely construct and maintain the orbiting International Space Station. To qualify for flight assignments, astronauts must demonstrate the ability to work safely and efficiently in the physically demanding environment of the spacesuit, possess an acute ability to resolve unforeseen problems, and implement proper tool protocols to ensure no tools will be lost in space. Through the insights and the lessons learned by actual EVA astronauts and EVA instructors, this paper twill take you on a journey through an astronaut's earliest experiences working in the spacesuit. termed the Extravehicular Mobility Unit (EMU), in the underwater training environment of the NBL. This work details an actual Suit Qualification NBL training event, outlines the numerous challenges the astronauts face throughout their initial training, and the various ways they adapt their own abilities to overcome them. The goal of this paper is to give everyone a small glimpse into what it is really like to work in a spacesuit.
Author
EXTRAVEHICULAR ACTIVITY; SPACE SUITS; ASTRONAUT TRAINING; INTERNATIONAL SPACE STATION
20090034244 NASA Marshall Space Flight Center, Huntsville, AL, United States
Performance of a Cylindrical Hall-Effect Thruster Using Permanent Magnets
Polzin, Kurt A.; Raitses, Y.; Merino, E.; Fisch, N. J.; August 02, 2009; In English; 45th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, 2-5 Aug. 2009, Denver, CO, United States; Original contains color illustrations
Report No.(s): M09-0243; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034244
While annular Hall thrusters can operate at high efficiency at kW power levels, it is difficult to construct one that operates over a broad envelope from 1 kW down to 100 W while maintaining an efficiency of 45-55%. Scaling to low power while holding the main dimensionless parameters constant requires a decrease in the thruster channel size and an increase in the magnetic field strength. Increasing the magnetic field becomes technically challenging since the field can saturate the miniaturized inner components of the magnetic circuit and scaling down the magnetic circuit leaves very little room for magnetic pole pieces and heat shields. In addition, the central magnetic pole piece defining the interior wall of the annular channel can experience excessive heat loads in a miniaturized Hall thruster, with the temperature eventually exceeding the Curie temperature of the material and in extreme circumstances leading to accelerated erosion of the channel wall. An alternative approach is to employ a cylindrical Hall thruster (CHT) geometry. Laboratory model CHTs have operated at power levels ranging from 50 W up to 1 kW. These thrusters exhibit performance characteristics that are comparable to conventional, annular Hall thrusters of similar size. Compared to the annular Hall thruster, the CHTs insulator surface area to discharge chamber volume ratio is lower. Consequently, there is the potential for reduced wall losses in the channel of a CHT, and any reduction in wall losses should translate into lower channel heating rates and reduced erosion, making the CHT geometry promising for low-power applications. This potential for high performance in the low-power regime has served as the impetus for research and development efforts aimed at understanding and improving CHT performance. Recently, a 2.6 cm channel diameter permanent magnet CHT (shown in Fig. 1) was tested. This thruster has the promise of reduced power consumption over previous CHT iterations that employed electromagnets. Data are presented to expose the effect different controllable parameters have on the discharge and to summarize performance measurements (thrust, Isp, efficiency) obtained using a thrust stand. In addition, beam current data are presented to show the effect of the magnetic field topology on the plume profile and current utilization and to gain insight into the thruster s operation. These data extend and improve upon the results previously presented by the authors in Ref. [1].
Author
CYLINDRICAL BODIES; HALL EFFECT; HALL THRUSTERS; MAGNETIC FIELD CONFIGURATIONS; PERMANENT MAGNETS; SPACECRAFT PROPULSION
20090034245 NASA Marshall Space Flight Center, Huntsville, AL, United States
Real-Time Simulation of Ares I Launch Vehicle
Tobbe, Patrick; Matras, Alex; Wilson, Heath; Alday, Nathan; Walker, David; Betts, Kevin; Hughes, Ryan; Turbe, Michael; August 10, 2009; In English; AIAA Modeling and Simulation Technologies Conference, 10-13 Aug. 2009, Chicago, IL, United States
Contract(s)/Grant(s): NNM06AB35T
Report No.(s): M09-0255; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034245
The Ares Real-Time Environment for Modeling, Integration, and Simulation (ARTEMIS) has been developed for use by the Ares I launch vehicle System Integration Laboratory (SIL) at the Marshall Space Flight Center (MSFC). The primary purpose of the Ares SIL is to test the vehicle avionics hardware and software in a hardware-in-the-loop (HWIL) environment to certify that the integrated system is prepared for flight. ARTEMIS has been designed to be the real-time software backbone to stimulate all required Ares components through high-fidelity simulation. ARTEMIS has been designed to take full advantage of the advances in underlying computational power now available to support HWIL testing. A modular real-time design relying on a fully distributed computing architecture has been achieved. Two fundamental requirements drove ARTEMIS to pursue the use of high-fidelity simulation models in a real-time environment. First, ARTEMIS must be used to test a man-rated integrated avionics hardware and software system, thus requiring a wide variety of nominal and off-nominal simulation capabilities to certify system robustness. The second driving requirement - derived from a nationwide review of current state-of-the-art HWIL facilities - was that preserving digital model fidelity significantly reduced overall vehicle lifecycle cost by reducing testing time for certification runs and increasing flight tempo through an expanded operational envelope. These two driving requirements necessitated the use of high-fidelity models throughout the ARTEMIS simulation. The nature of the Ares mission profile imposed a variety of additional requirements on the ARTEMIS simulation. The Ares I vehicle is composed of multiple elements, including the First Stage Solid Rocket Booster (SRB), the Upper Stage powered by the J- 2X engine, the Orion Crew Exploration Vehicle (CEV) which houses the crew, the Launch Abort System (LAS), and various secondary elements that separate from the vehicle. At launch, the integrated vehicle stack is composed of these stages, and throughout the mission, various elements separate from the integrated stack and tumble back towards the earth. ARTEMIS must be capable of simulating the integrated stack through the flight as well as propagating each individual element after separation. In addition, abort sequences can lead to other unique configurations of the integrated stack as the timing and sequence of the stage separations are altered.
Author
ARES 1 LAUNCH VEHICLE; REAL TIME OPERATION; LAUNCH VEHICLES; SYSTEMS INTEGRATION; COMPUTERIZED SIMULATION; LAUNCHING; CREW EXPLORATION VEHICLE
20090034247 Dynamic Concepts, Inc., Huntsville, AL, United States
Real-Time Hardware-in-the-Loop Simulation of Ares I Launch Vehicle
Tobbe, Patrick; Matras, Alex; Walker, David; Wilson, Heath; Fulton, Chris; Alday, Nathan; Betts, Kevin; Hughes, Ryan; Turbe, Michael; August 10, 2009; In English; AIAA Modeling and Simulation Technologies Conference, 10-13 Aug. 2009, Chicago, IL, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): NNM08AB53T
Report No.(s): M09-0528; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034247
The Ares Real-Time Environment for Modeling, Integration, and Simulation (ARTEMIS) has been developed for use by the Ares I launch vehicle System Integration Laboratory at the Marshall Space Flight Center. The primary purpose of the Ares System Integration Laboratory is to test the vehicle avionics hardware and software in a hardware - in-the-loop environment to certify that the integrated system is prepared for flight. ARTEMIS has been designed to be the real-time simulation backbone to stimulate all required Ares components for verification testing. ARTE_VIIS provides high -fidelity dynamics, actuator, and sensor models to simulate an accurate flight trajectory in order to ensure realistic test conditions. ARTEMIS has been designed to take advantage of the advances in underlying computational power now available to support hardware-in-the-loop testing to achieve real-time simulation with unprecedented model fidelity. A modular realtime design relying on a fully distributed computing architecture has been implemented.
Author
ARES 1 LAUNCH VEHICLE; COMPUTER PROGRAMS; HARDWARE-IN-THE-LOOP SIMULATION; REAL TIME OPERATION; SYSTEMS INTEGRATION; COMPUTERIZED SIMULATION; AVIONICS
20090034248 ATK Launch Systems, Brigham City, UT, United States
Compartment Venting Analyses of Ares I First Stage Systems Tunnel
Wang, Qunzhen; Arner, Stephen; August 02, 2009; In English; 45th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 2-5 Aug. 2009, Denver, CO, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): NNM07AA75C
Report No.(s): M09-0512; Copyright; Avail.: CASI: A04, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034248
Compartment venting analyses have been performed for the Ares I first stage systems tunnel using both the lumped parameter method and the three-dimensional (31)) transient computational fluid dynamics (CFD) approach. The main objective of venting analyses is to predict the magnitudes of differential pressures across the skin so the integrity of solid walls can be evaluated and properly designed. The lumped parameter method assumes the gas pressure and temperature inside the systems tunnel are spatially uniform, which is questionable since the tunnel is about 1,700 in. long and 4 in. wide. Therefore, 31) transient CFD simulations using the commercial CFD code FLUENT are performed in order to examine the gas pressure and temperature variations inside the tunnel. It was found that the uniform pressure and temperature assumptions inside the systems tunnel are valid during ascent. During reentry, the uniform pressure assumption is also reasonable but the uniform temperature assumption is not valid. Predicted pressure and temperature inside the systems tunnel using CFD are also compared with those from the lumped parameter method using the NASA code CHCHVENT. In general, the average pressure and temperature inside the systems tunnel from CFD are between the burst and crush results from CHCHVENT during both ascent and reentry. The skin differential pressure and pressure inside the systems tunnel relative to freestream pressure from CHCHVENT as well as velocity vectors and streamlines are also discussed in detail.
Author
ARES 1 FIRST STAGE; COMPUTATIONAL FLUID DYNAMICS; VENTING; GAS PRESSURE; FREE FLOW; DIMENSIONAL ANALYSIS; ASCENT; DIFFERENTIAL PRESSURE
20090034251 NASA Marshall Space Flight Center, Huntsville, AL, United States
CIV Polarization Measurements using a Vacuum Ultraviolet Fabry-Perot Interferometer
West, Edward; Gary, G. Allen; Cirtain, Jonathan; David, John; Kobayashi, Ken; Pietraszewski, Chris; August 02, 2009; In English; SPIE Optics + Photonics 2009, 1-6 Aug. 2009, San Diego, CA, United States; Original contains color illustrations
Report No.(s): M09-0572; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034251
Marshall Space Flight Center's (MSFC) is developing a Vacuum Ultraviolet (VUV) Fabry-P rot Interferometer that will be launched on a sounding rocket for high throughput, high-cadence, extended field of view CIV (155nm) measurements. These measurements will provide (i) Dopplergrams for studies of waves, oscillations, explosive events, and mass motions through the transition region, and, (ii), polarization measurements to study the magnetic field in the transition region. This paper will describe the scientific goals of the instrument, a brief description of the optics and the polarization characteristics of the VUV Fabry P rot.
Author
FABRY-PEROT INTERFEROMETERS; MAGNETIC FIELDS; FAR ULTRAVIOLET RADIATION; FIELD OF VIEW; POLARIZATION CHARACTERISTICS; SOUNDING ROCKETS
20090034252 NASA Marshall Space Flight Center, Huntsville, AL, United States
Spectral Calibration of the MSFC Solar Ultraviolet Magnetograph
West, Edward; Kobayashi, Ken; Cirtain, Jonathan; Gary, Allen; Davis, John; Reader, Joseph; August 02, 2009; In English; SPIE Optics + Photonics 2009, 1-6 Aug. 2009, San Diego, CA, United States; Original contains color illustrations
Report No.(s): M09-0574; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034252
This paper describes the scientific goals of a sounding rocket program called the Solar Ultraviolet Magnetograph Investigation (SUMI), presents a brief description of the optics that were developed to meet those goals and discusses the spectral, spatial and polarization characteristics of SUMI's Toroidal Variable-Line-Space (TVLS) gratings; which are critical to SUMI's measurements of the magnetic field in the Sun's transition region.
Author
SOLAR INSTRUMENTS; MAGNETOMETERS; SOUNDING ROCKETS; MAGNETIC FIELDS; CALIBRATING
20090034253 NASA Marshall Space Flight Center, Huntsville, AL, United States
Implementation of an Online Database for Chemical Propulsion Systems
David B. Owen, II; McRight, Patrick S.; Cardiff, Eric H.; August 02, 2009; In English; 45th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 2-5 Aug. 2009, Denver, CO, United States; Original contains color illustrations
Report No.(s): M09-0575; Copyright; Avail.: CASI: A02, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034253
The Johns Hopkins University, Chemical Propulsion Information Analysis Center (CPIAC) has been working closely with NASA Goddard Space Flight Center (GSFC); NASA Marshall Space Flight Center (MSFC); the University of Alabama at Huntsville (UAH); The Johns Hopkins University, Applied Physics Laboratory (APL); and NASA Jet Propulsion Laboratory (JPL) to capture satellite and spacecraft propulsion system information for an online database tool. The Spacecraft Chemical Propulsion Database (SCPD) is a new online central repository containing general and detailed system and component information on a variety of spacecraft propulsion systems. This paper only uses data that have been approved for public release with unlimited distribution. The data, supporting documentation, and ability to produce reports on demand, enable a researcher using SCPD to compare spacecraft easily, generate information for trade studies and mass estimates, and learn from the experiences of others through what has already been done. This paper outlines the layout and advantages of SCPD, including a simple example application with a few chemical propulsion systems from various NASA spacecraft.
Author
PROPULSION SYSTEM CONFIGURATIONS; CHEMICAL PROPULSION; DATA BASES; PROPULSION SYSTEM PERFORMANCE; SPACECRAFT PROPULSION; INFORMATION SYSTEMS
20090034254 NASA Marshall Space Flight Center, Huntsville, AL, United States
Potential Science Missions Enabled by NASA's Planned Ares V
Stahl, H. Philip; Thronson, Harley; Langhoff, Stephani; Postman, Marc; Lester, Daniel; Lillie, Chuck; August 02, 2009; In English; SPIE UV/Optical/IR Space Telescopes: Innovative Technologies and Concepts IV, 3-5 Aug. 2009, San Diego, CA, United States; Original contains black and white illustrations
Report No.(s): M09-0580; Copyright; Avail.: CASI: A02, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034254
NASA s planned Ares V cargo vehicle with its 10 meter diameter fairing and ~60,000 kg payload mass to L2 offers the potential to launch entirely new classes of space science missions such as 8-meter monolithic aperture telescopes, 12-meter aperture x-ray telescopes, 16 to 24 meter segmented telescopes and highly capable outer planet missions. The paper will summarize the current Ares V baseline performance capabilities and review potential mission concepts enabled by these capabilities.
Author
ARES 5 CARGO LAUNCH VEHICLE; MISSION PLANNING; PAYLOADS; SPACE MISSIONS; X RAY TELESCOPES; CARGO
20090034255 NASA Dryden Flight Research Center, Edwards, CA, United States
Stability and Control Analysis of the F-15B Quiet SpikeTM Aircraft
McWherter, Shaun C.; Moua, Cheng M.; Gera, Joseph; Cox, Timothy H.; August 2009; In English; Original contains color illustrations
Contract(s)/Grant(s): NAS4-02021
Report No.(s): NASA/TM-2009-214651; H-2956; DFRC-654; Copyright; Avail.: CASI: A04, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034255
The primary purpose of the Quiet Spike(TradeMark) flight research program was to analyze the aerodynamic, structural, and mechanical proof-of-concept of a large multi-stage telescoping nose spike installed on the National Aeronautics and Space Administration Dryden Flight Research Center (Edwards, California) F-15B airplane. This report describes the preflight stability and control analysis performed to assess the effect of the spike on the stability, controllability, and handling qualities of the airplane; and to develop an envelope expansion approach to maintain safety of flight. The overall flight test objective was to collect flight data to validate the spike structural dynamics and loads model up to Mach 1.8. Other objectives included validating the mechanical feasibility of a morphing fuselage at operational conditions and determining the near-field shock wave characterization. The two main issues relevant to the stability and control objectives were the effects of the spike-influenced aerodynamics on the F-15B airplane flight dynamics, and the air data and angle-of-attack sensors. The analysis covered the sensitivity of the stability margins, and the handling qualities due to aerodynamic variation and the maneuvering limitations of the F-15B Quiet Spike configuration. The results of the analysis and the implications for the flight test program are also presented.
Author
STABILITY TESTS; AERODYNAMICS; DYNAMIC STRUCTURAL ANALYSIS; FLIGHT TESTS; ANGLE OF ATTACK; SPIKES (AERODYNAMIC CONFIGURATIONS); AEROMANEUVERING
20090034262 NASA Marshall Space Flight Center, Huntsville, AL, United States
In-Situ Measurement of Hall Thruster Erosion Using a Fiber Optic Regression Probe
Polzin, Kurt; Korman, Valentin; August 02, 2009; In English; 45th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 2-5 Aug. 2009, Denver, CO, United States; Original contains black and white illustrations
Report No.(s): M09-0244; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034262
One potential life-limiting mechanism in a Hall thruster is the erosion of the ceramic material comprising the discharge channel. This is especially true for missions that require long thrusting periods and can be problematic for lifetime qualification, especially when attempting to qualify a thruster by analysis rather than a test lasting the full duration of the mission. In addition to lifetime, several analytical and numerical models include electrode erosion as a mechanism contributing to enhanced transport properties. However, there is still a great deal of dispute over the importance of erosion to transport in Hall thrusters. The capability to perform an in-situ measurement of discharge channel erosion is useful in addressing both the lifetime and transport concerns. An in-situ measurement would allow for real-time data regarding the erosion rates at different operating points, providing a quick method for empirically anchoring any analysis geared towards lifetime qualification. Erosion rate data over a thruster s operating envelope would also be useful in the modeling of the detailed physics inside the discharge chamber. There are many different sensors and techniques that have been employed to quantify discharge channel erosion in Hall thrusters. Snapshots of the wear pattern can be obtained at regular shutdown intervals using laser profilometry. Many non-intrusive techniques of varying complexity and sensitivity have been employed to detect the time-varying presence of erosion products in the thruster plume. These include the use quartz crystal microbalances, emission spectroscopy, laser induced flourescence, and cavity ring-down spectroscopy. While these techniques can provide a very accurate picture of the level of eroded material in the thruster plume, it is more difficult to use them to determine the location from which the material was eroded. Furthermore, none of the methods cited provide a true in-situ measure of erosion at the channel surface while the thruster is in operation (i.e. none yield a continuous channel erosion measurement). A recent fundamental sensor development effort has led to a novel regression, erosion, and ablation sensor technology (REAST). The REAST sensor allows for measurement of real-time surface erosion rates at a discrete surface location. The sensor was tested using a linear Hall thruster geometry (see Fig. 1), which served as a means of producing plasma erosion of a ceramic discharge chamber. The mass flow rate, discharge voltage, and applied magnetic field strength could be varied, allowing for erosion measurements over a broad thruster operating envelope. Results are presented demonstrating the ability of the REAST sensor to capture not only the insulator erosion rates but also changes in these rates as a function of the discharge parameters.
Author
EROSION; FIBER OPTICS; HALL THRUSTERS; IN SITU MEASUREMENT; MATHEMATICAL MODELS; SPECTROSCOPY; PROBES
20090034325 NASA Marshall Space Flight Center, Huntsville, AL, United States
A Fiber-Optic Sensor for Leak Detection in a Space Environment
Sinko, John E.; Korman, Valentin; Hendrickson, Adam; Polzin, Kurt A.; August 03, 2009; In English; 45th AIAA/ASME/ASEE/SAE Joint Propulsion Conference and Exhibit/American Institute of Aeronautics and Astronautics, 3-5 Aug. 2009, Denver, CO, United States; Original contains black and white illustrations
Contract(s)/Grant(s): NAS8-02060
Report No.(s): M09-0608; Copyright; Avail.: CASI: A02, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034325
A miniature fiber-optic, laser-based, interferometric leak detector is presented for application as a means to detect on-orbit gas leaks. The sensor employs a fiber-coupled modified Michelson interferometer to detect gas leaks by measuring an increase in gas density in the sensing region. Monitoring changes in the fringe pattern output by the interferometer allows for direct measurement of the gas density in the sensing region and, under the assumption of an equation of state, this can be used to obtain a pressure measurement. Measurements obtained over a pressure range from 20 mtorr to 760 torr using a prototypical interferometer on working gases of air, nitrogen, argon, and helium generally exhibit agreement with a theoretical prediction of the pressure increase required before an interference fringe completely moves over the detector. Additional measurements performed on various gases demonstrate the range of detectable species, measuring sub-torr pressure changes in the process. A high-fidelity measurement places the ultimate pressure resolution for this particular sensor configuration in the 10 mtorr range. Time-resolved data prove the capability of this sensor to detect fast gas flow phenomena associated with transients and pressure waves.
Author
GAS FLOW; GAS DENSITY; FIBER OPTICS; MICHELSON INTERFEROMETERS; PRESSURE MEASUREMENT; LEAKAGE; DETECTION
20090034327 NASA Marshall Space Flight Center, Huntsville, AL, United States
Development and Utilization of Space Fission Power Systems
Houts, Michael G.; Mason, Lee S.; Palac, Donald T.; Harlow, Scott E.; August 03, 2009; In English; 7th Intersociety Energy Conversion Engineering Conference, 2-5 Aug. 2009, Denver, CO, United States; Original contains color illustrations
Report No.(s): M09-0615; No Copyright; Avail.: CASI: A02, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034327
Space fission power systems could enable advanced civilian space missions. Terrestrially, thousands of fission systems have been operated since 1942. In addition, the US flew a space fission system in 1965, and the former Soviet Union flew 33 such systems prior to the end of the Cold War. Modern design and development practices, coupled with 65 years of experience with terrestrial reactors, could enable the affordable development of space fission power systems for near-term planetary surface applications.
Author
SPACECRAFT POWER SUPPLIES; FISSION; PLANETARY SURFACES; SPACE MISSIONS
20090034329 NASA Marshall Space Flight Center, Huntsville, AL, United States
Preliminary Cost Model for Space Telescopes
Stahl, H. Philip; Prince, F. Andrew; Smart, Christian; Stephens, Kyle; Henrichs, Todd; August 02, 2009; In English; SPIE Conference UV/Optical/IR Space Telescopes: Innovative Technologies and Concepts IV, 2-5 Aug. 2009, San Diego, CA, United States
Report No.(s): M09-0632; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034329
Parametric cost models are routinely used to plan missions, compare concepts and justify technology investments. However, great care is required. Some space telescope cost models, such as those based only on mass, lack sufficient detail to support such analysis and may lead to inaccurate conclusions. Similarly, using ground based telescope models which include the dome cost will also lead to inaccurate conclusions. This paper reviews current and historical models. Then, based on data from 22 different NASA space telescopes, this paper tests those models and presents preliminary analysis of single and multi-variable space telescope cost models.
Author
COST ANALYSIS; SPACEBORNE TELESCOPES; MATHEMATICAL MODELS; COSTS
20090034330 NASA Marshall Space Flight Center, Huntsville, AL, United States
Design for an 8 Meter Monolithic UV/OIR Space Telescope
Stahl, H. Philip; Postman, Marc; Hornsby, Linda; Hopkins, Randall; Mosier, Gary E.; Pasquale, Bert A.; Arnold, William R.; August 02, 2009; In English; SPIE Conference UV/Optical/IR Space Telescopes: Innovative Technologies and Concepts IV, 2-5 Aug. 2009, San Diego, CA, United States; Original contains color and black and white illustrations
Copyright; Avail.: CASI: A02, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034330
ATLAST-8 is an 8-meter monolithic UV/optical/NIR space observatory to be placed in orbit at Sun-Earth L2 by NASA's planned Ares V cargo launch vehicle. The ATLAST-8 will yield fundamental astronomical breakthroughs. The mission concept utilizes two enabling technologies: planned Ares-V launch vehicle (scheduled for 2019) and autonomous rendezvous and docking (AR&D). The unprecedented Ares-V payload and mass capacity enables the use of a massive, monolithic, thin-meniscus primary mirror - similar to a VLT or Subaru. Furthermore, it enables simple robust design rules to mitigate cost, schedule and performance risk. AR&D enables on-orbit servicing, extending mission life and enhancing science return.
Author
ARES 5 CARGO LAUNCH VEHICLE; ULTRAVIOLET TELESCOPES; SPACEBORNE TELESCOPES; ORBITAL RENDEZVOUS; SPACECRAFT DOCKING; AUTONOMOUS DOCKING; LAUNCH VEHICLES; MISSION PLANNING; PAYLOADS; ASTRONOMY
Additions to the NASA Aeronautics and Space Database as of 10/14/2009
20090034387 NASA Marshall Space Flight Center, Huntsville, AL, United States
Comparison of the Effects of RAS vs. Kain-Fritsch Convective Schemes on Katrina Forecasts with GEOS-5
Miller, Timothy L.; Cohen, Charles; Paxton, Jessica; Robertson, F. R. (Pete); August 10, 2009; In English; Workshop in High Resolution Climate Modeling, 10-14 Aug. 2009, Trieste, Italy; Original contains color illustrations
Report No.(s): M09-0603; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034387
Global forecasts were made with the 0.25-degree latitude version of GEOS-5, with the RAS scheme and with the Kain-Fritsch scheme. Examination was made of the Katrina (2005) hurricane simulation. Replacement of the RAS convective scheme with the K-F scheme results in a much more vigorous Katrina, closer to reality. Still, the result is not as vigorous as reality. In terms of wind maximum, the gap was closed by ~50%. The result seems to be due to the RAS scheme drying out the boundary layer, thus hampering the grid-scale secondary circulation and attending cyclone development. The RAS case never developed a full warm core, whereas the K-F case did. Not shown here: The K-F scheme also resulted in a more vigorous storm than when GEOS-5 is run with no convective parameterization. Also not shown: An experiment in which the RAS firing level was moved up by 3 model levels resulted in a stronger, warm-core storm, though not as strong as the K-F case. Effects on storm track were noticed, but not studied.
Author
HURRICANES; STORMS; FORECASTING; BOUNDARY LAYERS; CONVECTION; CYCLONES
20090034389 NASA Marshall Space Flight Center, Huntsville, AL, United States
Ares V: Game Changer for National Security Launch
Sumrall, Phil; Morris, Bruce; August 23, 2009; In English; Emerging and Enabling Technology Conference, 24-27 Aug. 2009, Huntsville, AL, United States; Original contains color illustrations
Report No.(s): M09-0605; M09-0469; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034389
NASA is designing the Ares V cargo launch vehicle to vastly expand exploration of the Moon begun in the Apollo program and enable the exploration of Mars and beyond. As the largest launcher in history, Ares V also represents a national asset offering unprecedented opportunities for new science, national security, and commercial missions of unmatched size and scope. The Ares V is the heavy-lift component of NASA's dual-launch architecture that will replace the current space shuttle fleet, complete the International Space Station, and establish a permanent human presence on the Moon as a stepping-stone to destinations beyond. During extensive independent and internal architecture and vehicle trade studies as part of the Exploration Systems Architecture Study (ESAS), NASA selected the Ares I crew launch vehicle and the Ares V to support future exploration. The smaller Ares I will launch the Orion crew exploration vehicle with four to six astronauts into orbit. The Ares V is designed to carry the Altair lunar lander into orbit, rendezvous with Orion, and send the mated spacecraft toward lunar orbit. The Ares V will be the largest and most powerful launch vehicle in history, providing unprecedented payload mass and volume to establish a permanent lunar outpost and explore significantly more of the lunar surface than was done during the Apollo missions. The Ares V consists of a Core Stage, two Reusable Solid Rocket Boosters (RSRBs), Earth Departure Stage (EDS), and a payload shroud. For lunar missions, the shroud would cover the Lunar Surface Access Module (LSAM). The Ares V Core Stage is 33 feet in diameter and 212 feet in length, making it the largest rocket stage ever built. It is the same diameter as the Saturn V first stage, the S-IC. However, its length is about the same as the combined length of the Saturn V first and second stages. The Core Stage uses a cluster of five Pratt & Whitney Rocketdyne RS-68B rocket engines, each supplying about 700,000 pounds of thrust. Its propellants are liquid hydrogen and liquid oxygen. The two solid rocket boosters provide about 3.5 million pounds of thrust at liftoff. These 5.5-segment boosters are derived from the 4-segment boosters now used on the Space Shuttle, and are similar to those used in the Ares I first stage. The EDS is powered by one J-2X engine. The J-2X, which has roughly 294,000 pounds of thrust, also powers the Ares I Upper Stage. It is derived from the J-2 that powered the Saturn V second and third stages. The EDS performs two functions. Its initial suborbital burns will place the lunar lander into a stable Earth orbit. After the Orion crew vehicle, launched separately on an Ares I, docks with the lander/EDS stack, EDS will ignite a second time to put the combined 65-metric ton vehicle into a lunar transfer orbit. When it stands on the launch pad at Kennedy Space Center late in the next decade, the Ares V stack will be approximately 381 feet tall and have a gross liftoff mass of 8.1 million pounds. The current point-of-departure design exceeds Saturn V s mass capability by approximately 40 percent. Using the current payload shroud design, Ares V can carry 315,000 pounds to 29-degree low Earth orbit (LEO) or 77,000 pounds to a geosynchronous orbit. Another unique aspect of the Ares V is the 33-foot-diameter payload shroud, which encloses approximately 30,400 cubic feet of usable volume. A larger hypothetical shroud for encapsulating larger payloads has been studied. While Ares V makes possible larger payload masses and volumes, it may alternately make possible more cost-effective mission design if the relevant payload communities are willing to consider an alternative to the existing approach that has driven them to employ complexity to solve current launch vehicle mass and volume constraints. By using Ares V s mass and volume capabilities as margin, payload designers stand to reduce development risk and cost. Significant progress has been made on the Ares V to support a plaed fiscal 2011 authority-to-proceed (ATP) milestone. The Ares V team is actively reaching out to external organizations during this early concept phase to ensure that the Ares V vehicle can be leveraged for national security, science, and commercial development needs. This presentation will discuss Ares V vehicle configuration, the path to the current concept, accomplishments to date, and potential payload utilization opportunities.
Author
ARES 5 CARGO LAUNCH VEHICLE; LAUNCHING; MISSION PLANNING; PAYLOADS; ROCKET ENGINES; SECURITY
20090034391 NASA Marshall Space Flight Center, Huntsville, AL, United States
Influence of Containment on Defects in GeSi Crystals
Volz, M. P.; Croell, A.; Mazuruk, K.; August 09, 2009; In English; 17th American Conference on Crystal Growth and Epitaxy/14th Biennial Workshop on Organometallic Vapor Phase Epitaxy/6th International Workshop on Modeling in Crystal Growth, 9-14 Aug. 2009, Lake Geneva, WI, United States; Original contains color and black and white illustrations
Report No.(s): M09-0621; M09-0437; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034391
Crystals grown without being in contact with a container have superior quality to otherwise similar crystals grown in direct contact with a container, especially with respect to impurity incorporation, formation of dislocations, and residual stress in crystals. "Detached" or "dewetted" Bridgman growth is similar to regular Bridgman growth in that most of the melt is in contact with the crucible wall, but the crystal is separated from the wall by a small gap, typically of the order of 10(exp -5) m. A small meniscus bridges the gap between the top of the crystal and the wall. Key parameters involved in achieving detached growth are the contact angle between the melt and crucible and the pressure differential across the meniscus. Sessile drop measurements were used to determine the wetting angles of Ge(sub 1-x)Si(sub x) melts on a variety of substrates and found that the highest wetting angles were achieved with pyrolitic boron nitride (pBN). GeSi crystals have been repeatedly grown detached in pBN crucibles but only occasionally in crucibles with lower wetting angles. Experiments have been conducted to assess the effect of pressure differential across the meniscus in sealed crucibles. This was done by adjusting the temperature profile after partial melting of the starting material. In a separate set of experiments, the pressure was controlled by connecting the volume below the meniscus to a regulated gas supply. The experiments were in agreement with calculations which predicted that stable detachment will only occur in crucibles with a low wetting angle over a relatively narrow range of pressure differential. Detached-grown crystals exhibited superior structural quality as evidenced by measurements of etch pit density, synchrotron white beam X-ray topography and double axis X-ray diffraction.
Author
CRYSTAL GROWTH; CRYSTALS; CONTAINERLESS MELTS; CRYSTAL MORPHOLOGY; GERMANIUM ALLOYS; SILICON ALLOYS; SILICON; GERMANIUM
20090034393 NASA Marshall Space Flight Center, Huntsville, AL, United States
Numerical Optimization of the Thermal Field in Bridgman Detached Growth
Stelian, C.; Volz, M. P.; Derby, J. J.; August 09, 2009; In English; 17th American Conference on Crystal Growth and Epitaxy/14th Biennial Workshop on Organometallic Vapor Phase Epitaxy/6th International Workshop on Modeling in Crystal Growth, 9-14 Aug. 2009, Lake Geneva, SI, United States; Original contains color illustrations
Report No.(s): M09-0622; M09-0446; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034393
The global modeling of the thermal field in two vertical Bridgman-like crystal growth configurations, has been performed to get optimal thermal conditions for a successful detached growth of Ge and CdTe crystals. These computations are performed using the CrysMAS code and expand upon our previous analysis [1] that propose a new mechanism involving the thermal field and meniscus position to explain stable conditions for dewetted Bridgman growth. The analysis of the vertical Bridgman configuration with two heaters, used by Palosz et al. for the detached growth of Ge, shows, consistent with their results, that the large wetting angle of germanium on boron nitride surfaces was an important factor to promote a successful detached growth. Our computations predict that by initiating growth much higher into the hot zone of the furnace, the thermal conditions will be favorable for continued detachment even for systems that did not exhibit high contact angles. The computations performed for a vertical gradient freeze configuration with three heaters representative of that used for the detached growth of CdTe, show favorable thermal conditions for dewetting during the entirely growth run described. Improved thermal conditions are also predicted for coated silica crucibles when the solid-liquid interface advances higher into the hot zone during the solidification process. The second set of experiments on CdTe growth described elsewhere has shown the reattachment of the crystal to the crucible after few centimeters of dewetted growth. The thermal modeling of this configuration shows a second solidification front appearing at the top of the sample and approaching the middle line across the third heater. In these conditions, the crystal grows detached from the bottom, but will be attached to the crucible in the upper part because of the solidification without gap in this region. The solidification with two interfaces can be avoided when the top of the sample is positioned below the middle position of the third furnace.
Author
BRIDGMAN METHOD; CRUCIBLES; CRYSTAL GROWTH; CRYSTALS; MATHEMATICAL MODELS; NUMERICAL ANALYSIS; OPTIMIZATION; TEMPERATURE EFFECTS
20090034394 Alabama Univ., Huntsville, AL, United States
Stability of Detached Solidification
Mazuruk, K.; Volz, M. P.; Croell, A.; August 09, 2009; In English; 17th American Conference on Crystal Growth and Epitaxy/14th Biennial Workshop on Organometallic Vapor Phase Epitaxy/6th International Workshop on Modeling in Crystal Growth, 9-14 Aug. 2009, Lake Geneva, WI, United States; Original contains color illustrations
Report No.(s): M09-0624; M09-0438; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034394
Bridgman crystal growth can be conducted in the so-called "detached" solidification regime, where the growing crystal is detached from the crucible wall. A small gap between the growing crystal and the crucible wall, of the order of 100 micrometers or less, can be maintained during the process. A meniscus is formed at the bottom of the melt between the crystal and crucible wall. Under proper conditions, growth can proceed without collapsing the meniscus. The meniscus shape plays a key role in stabilizing the process. Thermal and other process parameters can also affect the geometrical steady-state stability conditions of solidification. The dynamic stability theory of the shaped crystal growth process has been developed by Tatarchenko. It consists of finding a simplified autonomous set of differential equations for the radius, height, and possibly other process parameters. The problem then reduces to analyzing a system of first order linear differential equations for stability. Here we apply a modified version of this theory for a particular case of detached solidification. Approximate analytical formulas as well as accurate numerical values for the capillary stability coefficients are presented. They display an unexpected singularity as a function of pressure differential. A novel approach to study the thermal field effects on the crystal shape stability has been proposed. In essence, it rectifies the unphysical assumption of the model that utilizes a perturbation of the crystal radius along the axis as being instantaneous. It consists of introducing time delay effects into the mathematical description and leads, in general, to stability over a broader parameter range. We believe that this novel treatment can be advantageously implemented in stability analyses of other crystal growth techniques such as Czochralski and float zone methods.
Author
BRIDGMAN METHOD; CRYSTAL GROWTH; CRYSTALS; DYNAMIC STABILITY; MATHEMATICAL MODELS; SOLIDIFICATION; STABILITY
20090034396 NASA Marshall Space Flight Center, Huntsville, AL, United States
Bond Assembly FOD Zones - A Procedure for Assuring Acceptable Adhesion
Evans, Kurt; Wurth, Laura; Mitchell, Mark; August 11, 2009; In English; 30th National Aerospace FOD Prevention Conference, 11-13 Aug. 2009, Layton City, UT, United States; Original contains color illustrations
Report No.(s): M09-0627; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034396
Rocket motor components are primarily assembled by adhesion. a) For example, the RSRM (Reusable Solid Rocket Motor - part of the Space Shuttle Boosters) system contains 10,000 sq ft of bondline area. b) Rocket motors contain a variety of adhesive/substrate bond systems c) Bond system performance requirements also vary. To assemble reliable components, ATK Space Systems and customers invest substantial resources to the study of bond assembly processes. a) Surface and adhesion science; b) Adhesive chemistry; c) Process parameters; d) Contamination effects.
Author
ADHESION; SOLID PROPELLANT ROCKET ENGINES; CONTAMINATION; BONDED JOINTS; AEROSPACE SYSTEMS; ASSEMBLING; ADHESIVES
20090034397 NASA Marshall Space Flight Center, Huntsville, AL, United States
Heavy Lift for National Security: The Ares V
Sumrall, Phil; August 17, 2009; In English; Space and Missile Defense Conference and Exhibition 2009, 17-20 Aug. 2009, Huntsville, AL, United States; Original contains color illustrations
Report No.(s): M09-0628; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034397
The NASA Ares Projects Office is developing the launch vehicles to move the United States and humanity beyond low earth orbit. Ares I is a crewed vehicle, and Ares V is a heavy lift vehicle being designed to launch cargo into LEO and transfer cargo and crews to the Moon. This is a snapshot of development and capabilities. Ares V is early in the requirements formulation stage of development pending the outcome of the Review of U.S. Human Space Flight Plans Committee and White House action. The Ares V vehicle will be considered a national asset, creating unmatched opportunities for human exploration, science, national security, and space business.
Derived from text
ARES 5 CARGO LAUNCH VEHICLE; LIFT; NASA SPACE PROGRAMS; LAUNCH VEHICLE CONFIGURATIONS; AEROSPACE INDUSTRY
20090034416 NASA Marshall Space Flight Center, Huntsville, AL, United States
Development of a Silicon Drift Detector Array: An X-Ray Fluorescence Spectrometer for Remote Surface Mapping
Gaskin, Jessica A.; Carini, Gabriella A.; Wei, Chen; Elsner, Ronald F.; Kramer, Georgiana; De Geronimo, Gianluigi; Keister, Jeffrey W.; Zheng, Li; Ramsey, Brian D.; Rehak, Pavel; Siddons, D. Peter; August 02, 2009; In English; SPIE Optics + Photonics 2009 Conference, 2-6 Aug. 2009, San Diego, CA, United States; Original contains color illustrations
Report No.(s): M09-0655; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090034416
Over the past three years NASA Marshall Space Flight Center has been collaborating with Brookhaven National Laboratory to develop a modular Silicon Drift Detector (SDD) X-Ray Spectrometer (XRS) intended for fine surface mapping of the light elements of the moon. The value of fluorescence spectrometry for surface element mapping is underlined by the fact that the technique has recently been employed by three lunar orbiter missions; Kaguya, Chandrayaan-1, and Chang e. The SDD-XRS instrument we have been developing can operate at a low energy threshold (i.e. is capable of detecting Carbon), comparable energy resolution to Kaguya (<150 eV at 5.9 keV) and an order of magnitude lower power requirement, making much higher sensitivities possible. Furthermore, the intrinsic radiation resistance of the SDD makes it useful even in radiation-harsh environments such as that of Jupiter and its surrounding moons.
Author
X RAY FLUORESCENCE; RADIATION TOLERANCE; X RAY SPECTROMETERS; DETECTION; SILICON
Additions to the NASA Aeronautics and Space Database as of 10/27/2009
20090035801 NASA Langley Research Center, Hampton, VA, United States
Technical Note: A Time-Dependent I(sub 0) Correction for Solar Occultation Instruments
Burton, Sharon P.; Thomason, Larry W.; Zawodny, Joseph M.; May 28, 2009; In English; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 479717.02.01.01.38
Report No.(s): LF99-8909; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035801
Solar occultation has proven to be a reliable technique for the measurement of atmospheric constituents in the stratosphere. NASA's Stratospheric Aerosol and Gas Experiments (SAGE, SAGE II, and SAGE III) together have provided over 25 years of quality solar occultation data, a data record which has been an important resource for the scientific exploration of atmospheric composition and climate change. Herein, we describe an improvement to the processing of SAGE data that corrects for a previously uncorrected short-term timedependence in the calibration function. The variability relates to the apparent rotation of the scanning track with respect to the face of the sun due to the motion of the satellite. Correcting for this effect results in a decrease in the measurement noise in the Level 1 line-of-sight optical depth measurements of approximately 40% in the middle and upper stratospheric SAGE II and III where it has been applied. The technique is potentially useful for any scanning solar occultation instrument, and suggests further improvement for future occultation measurements if a full disk imaging system can be included.
Author
OCCULTATION; SOLAR INSTRUMENTS; SUN; TIME DEPENDENCE; SAGE SATELLITE
20090035802 NASA Johnson Space Center, Houston, TX, United States
The Integrated Medical Model: A Risk Assessment and Decision Support Tool for Space Flight Medical Systems
Kerstman, Eric; Minard, Charles; Saile, Lynn; deCarvalho, Mary Freire; Myers, Jerry; Walton, Marlei; Butler, Douglas; Iyengar, Sriram; Johnson-Throop, Kathy; Baumann, David; [2009]; In English; AsMA Annual meeting, 9-13 May 2010, Phoenix, AZ, United States
Report No.(s): JSC-CN-18951; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035802
The Integrated Medical Model (IMM) is a decision support tool that is useful to mission planners and medical system designers in assessing risks and designing medical systems for space flight missions. The IMM provides an evidence based approach for optimizing medical resources and minimizing risks within space flight operational constraints. The mathematical relationships among mission and crew profiles, medical condition incidence data, in-flight medical resources, potential crew functional impairments, and clinical end-states are established to determine probable mission outcomes. Stochastic computational methods are used to forecast probability distributions of crew health and medical resource utilization, as well as estimates of medical evacuation and loss of crew life. The IMM has been used in support of the International Space Station (ISS) medical kit redesign, the medical component of the ISS Probabilistic Risk Assessment, and the development of the Constellation Medical Conditions List. The IMM also will be used to refine medical requirements for the Constellation program. The IMM outputs for ISS and Constellation design reference missions will be presented to demonstrate the potential of the IMM in assessing risks, planning missions, and designing medical systems. The implementation of the IMM verification and validation plan will be reviewed. Additional planned capabilities of the IMM, including optimization techniques and the inclusion of a mission timeline, will be discussed. Given the space flight constraints of mass, volume, and crew medical training, the IMM is a valuable risk assessment and decision support tool for medical system design and mission planning.
Author
AEROSPACE MEDICINE; RISK ASSESSMENT; DECISION SUPPORT SYSTEMS; INTERNATIONAL SPACE STATION; SYSTEMS INTEGRATION; MODELS
20090035803 Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA, United States
A Theoretical Analysis of Steady-State Charge Collection in Simple Diodes under High-Injection Conditions
Edmonds, Larry D.; September 10, 2009; In English; Original contains black and white illustrations
Contract(s)/Grant(s): NAS7-03001WU 071119-1.77
Report No.(s): JPL-Publ-09-21; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035803
A previous rigorous mathematical analysis of drift-diffusion equations was used to investigate collected charge in a simple reverse-biased p-n junction diode exposed to an ionization source that liberates carriers (electron-hole pairs) in a quasi-neutral region within the diode. Each of two simple models was found to agree with the more rigorous analysis when carrier liberation is sufficiently intense. One is the sensitive volume (SV) model, and the other was called ambipolar diffusion with a cutoff (ADC). The earlier rigorous analysis was worked out in detail only for a localized source, i.e., a point source of carrier liberation, so it was able to validate the applicability of each simple model only for that case. The present paper treats an arbitrary spatial distribution of carrier generation and concludes that the ADC model remains valid for this more general case, but the SV model does not.
Author
DIODES; INJECTION; STEADY STATE; APPLICATIONS OF MATHEMATICS; MATHEMATICAL MODELS; P-N JUNCTIONS; HOLES (ELECTRON DEFICIENCIES)
Additions to the NASA Aeronautics and Space Database as of 10/28/2009
20090035815 NASA Johnson Space Center, Houston, TX, United States
Effect of Crack Opening on Penetrant Crack Detectability
Weaver, Devin; [2009]; In English; Original contains color and black and white illustrations
Report No.(s): JSC-CN-18717; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035815
Results: From the testing we were able to determine all the cracks within the test range were detectable or better with developer. Many of the indications after development lost their linearity and gave circular indications. Our tests were performed in a laboratory and our procedure would be difficult in an industrial setting. Conclusions: The "V" did not significantly affect our ability to detect the POD cracks with fluorescent penetrant. Conduct same experiment with more cracks. The 0.025 and 0.050 POD specimens are clean and documented with the SEM. Conduct water-wash fluorescent penetrant test at EAFB. The poppet cracks are tighter than the POD specimen cracks. Flight FCV poppets: 0.01 mils (0.3 microns) Langley fatigue cracked poppets: 0.02 mils (0.5 microns) POD specimen (post 5 mils): 0.05 mils (1.4 microns) We could not detect cracks in Langley fatigue-cracked poppets with fluorescent penetrant. Investigate inability of penetrant to wet the poppet surface.
Author
CRACKS; DETECTION; PENETRANTS; TEST RANGES; FLUORESCENCE
20090035818 NASA Langley Research Center, Hampton, VA, United States
An Exploratory Study of Runway Arrival Procedures: Time Based Arrival and Self-Spacing
Houston, Vincent E.; Barmore, Bryan; September 21, 2009; In English; 9th AIAA Aviation Technology, Integration, and Operations Conference, 21-24 Sep. 2009, Hilton Head, SC, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 411931.02.61.07.01
Report No.(s): LF99-8374; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035818
The ability of a flight crew to deliver their aircraft to its arrival runway on time is important to the overall efficiency of the National Airspace System (NAS). Over the past several years, the NAS has been stressed almost to its limits resulting in problems such as airport congestion, flight delay, and flight cancellation to reach levels that have never been seen before in the NAS. It is predicted that this situation will worsen by the year 2025, due to an anticipated increase in air traffic operations to one-and-a-half to three times its current level. Improved arrival efficiency, in terms of both capacity and environmental impact, is an important part of improving NAS operations. One way to improve the arrival performance of an aircraft is to enable the flight crew to precisely deliver their aircraft to a specified point at either a specified time or specified interval relative to another aircraft. This gives the flight crew more control to make the necessary adjustments to their aircraft s performance with less tactical control from the controller; it may also decrease the controller s workload. Two approaches to precise time navigation have been proposed: Time-Based Arrivals (e.g., required times of arrival) and Self-Spacing. Time-Based Arrivals make use of an aircraft s Flight Management System (FMS) to deliver the aircraft to the runway threshold at a given time. Self-Spacing enables the flight crew to achieve an ATC assigned spacing goals at the runway threshold relative to another aircraft. The Joint Planning and Development Office (JPDO), a multi-agency initiative established to plan and coordinate the development of the Next Generation Air Transportation System (NextGen), has asked for data for both of these concepts to facilitate future research and development. This paper provides a first look at the delivery performance of these two concepts under various initial and environmental conditions in an air traffic simulation environment.
Author
AIR TRAFFIC CONTROL; NATIONAL AIRSPACE SYSTEM; FLIGHT MANAGEMENT SYSTEMS; FLIGHT CREWS; RUNWAYS; AIR TRANSPORTATION; MANAGEMENT PLANNING
20090035819 Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA, United States
Reliability of Low-Pitch, High-I/O Area Array Packages
Ghaffarian, Reza; April 2009; In English; Original contains color and black and white illustrations
Contract(s)/Grant(s): NAS7-03001WBS 939904.01.11
Report No.(s): JPL-Publ-09-15; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035819
This report first provides a body of knowledge (BoK) survey for designing, manufacturing, and testing high input/ output (I/O) and low-pitch area array packages. It then presents test data on design, assembly, and environmental evaluation results for various newly available electronics packages assembled onto printed wiring boards (PWBs). Packages included plastic ball grid arrays (PBGAs) with I/Os up to 1156 and 1-mm pitch, high-I/O chip scale packages (CSPs), low-pitch flip chip, microlead frame/quad flat no lead (MLF/QFN), and small resistors to 0201 size. Finally, it summarizes lessons learned from test results for assembly and environmental testing along with optical, scanning electron microscopy (SEM), and x-ray photomicrographs showing damage progress.
Author
RELIABILITY; ELECTRONIC PACKAGING; NASA PROGRAMS; RELIABILITY ANALYSIS; CHIPS (ELECTRONICS); ARRAYS; TEST VEHICLES; PITCH (INCLINATION)
20090035820 NASA Ames Research Center, Moffett Field, CA, United States
A Corrosion Risk Assessment Model for Underground Piping
Datta, Koushik; Fraser, Douglas R.; January 26, 2009; In English; 2009 Annual Reliability and Maintainability Symposium (RAMS), 26-29 Jan. 2009, Fort Worth, TX, United States; Original contains color illustrations
Contract(s)/Grant(s): WBS 939904
Report No.(s): ARC-E-DAA-TN203; No Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035820
The Pressure Systems Manager at NASA Ames Research Center (ARC) has embarked on a project to collect data and develop risk assessment models to support risk-informed decision making regarding future inspections of underground pipes at ARC. This paper shows progress in one area of this project - a corrosion risk assessment model for the underground high-pressure air distribution piping system at ARC. It consists of a Corrosion Model of pipe-segments, a Pipe Wrap Protection Model; and a Pipe Stress Model for a pipe segment. A Monte Carlo simulation of the combined models provides a distribution of the failure probabilities. Sensitivity study results show that the model uncertainty, or lack of knowledge, is the dominant contributor to the calculated unreliability of the underground piping system. As a result, the Pressure Systems Manager may consider investing resources specifically focused on reducing these uncertainties. Future work includes completing the data collection effort for the existing ground based pressure systems and applying the risk models to risk-based inspection strategies of the underground pipes at ARC.
Author
CORROSION; RISK ASSESSMENT; PIPES (TUBES); SYSTEMS MANAGEMENT; HIGH PRESSURE; RISK
20090035821 NASA Glenn Research Center, Cleveland, OH, United States
Achieving a Prioritized Research and Technology Development Portfolio for the Dust Management Project
Hyatt, Mark J.; Abel, Phillip; Delaune, Paul; Fishman, Julianna; Kohli, Rajiv; March 07, 2009; In English; 2009 IEEE Aerospace Conference, 7-14 Mar. 2009, Big Sky, MT, United States
Report No.(s): ARC-E-DAA-TN216; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035821
Mission architectures for human exploration of the lunar surface continue to advance as well as the definitions of capability needs, best practices and engineering design to mitigate the impact of lunar dust on exposed systems. The NASA DMP has been established as the agency focal point for dust characterization, technology, and simulant development. As described in this paper, the DMP has defined a process for selecting and justifying its R&T portfolio. The technology prioritization process, which is based on a ranking system according to weighted criteria, has been successfully applied to the current DMP dust mitigation technology portfolio. Several key findings emerged from this assessment. Within the dust removal and cleaning technologies group, there are critical technical challenges that must be overcome for these technologies to be implemented for lunar applications. For example, an in-situ source of CO2 on the moon is essential to the CO2 shower technology. Also, significant development effort is required to achieve technology readiness level TRL 6 for the electrostatic cleaning system for removal of particles smaller than 50 pm. The baseline materials related technologies require considerable development just to achieve TRL 6. It is also a nontrivial effort to integrate the materials in hardware for lunar application. At present, there are no terrestrial applications that are readily adaptable to lunar surface applications nor are there any obvious leading candidates. The unique requirements of dust sealing systems for lunar applications suggest an extensive development effort will be necessary to mature dust sealing systems to TRL 6 and beyond. As discussed here, several alternate materials and technologies have achieved high levels of maturity for terrestrial applications and warrant due diligence in ongoing assessment of the technology portfolio. The present assessment is the initial step in an ongoing effort to continually evaluate the DMP technology portfolio and external non-NASA relevant technology developments efforts to maintain an optimal investment profile. At the same time, there is an ongoing review of agency-wide dust-related R&T activities. The results of these ongoing assessments will be reported in future publications.
Author
LUNAR DUST; LUNAR SURFACE; ELECTROSTATICS; CARBON DIOXIDE; CLEANING
20090035823 NASA Ames Research Center, Moffett Field, CA, United States
A Mixed Integer Linear Program for Airport Departure Scheduling
Gupta, Gautam; Jung, Yoon Chul; September 21, 2009; In English; AIAA 9th Aviation Technology, Integration, and Operations, 21-23 Sep. 2009, Hilton Head, SC, United States
Contract(s)/Grant(s): WBS 30529510
Report No.(s): ARC-E-DAA-TN365; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035823
Aircraft departing from an airport are subject to numerous constraints while scheduling departure times. These constraints include wake-separation constraints for successive departures, miles-in-trail separation for aircraft bound for the same departure fixes, and time-window or prioritization constraints for individual flights. Besides these, emissions as well as increased fuel consumption due to inefficient scheduling need to be included. Addressing all the above constraints in a single framework while allowing for resequencing of the aircraft using runway queues is critical to the implementation of the Next Generation Air Transport System (NextGen) concepts. Prior work on airport departure scheduling has addressed some of the above. However, existing methods use pre-determined runway queues, and schedule aircraft from these departure queues. The source of such pre-determined queues is not explicit, and could potentially be a subjective controller input. Determining runway queues and scheduling within the same framework would potentially result in better scheduling. This paper presents a mixed integer linear program (MILP) for the departure-scheduling problem. The program takes as input the incoming sequence of aircraft for departure from a runway, along with their earliest departure times and an optional prioritization scheme based on time-window of departure for each aircraft. The program then assigns these aircraft to the available departure queues and schedules departure times, explicitly considering wake separation and departure fix restrictions to minimize total delay for all aircraft. The approach is generalized and can be used in a variety of situations, and allows for aircraft prioritization based on operational as well as environmental considerations. We present the MILP in the paper, along with benefits over the first-come-first-serve (FCFS) scheme for numerous randomized problems based on real-world settings. The MILP results in substantially reduced delays as compared to FCFS, and the magnitude of the savings depends on the queue and departure fix structure. The MILP assumes deterministic aircraft arrival times at the runway queues. However, due to taxi time uncertainty, aircraft might arrive either earlier or later than these deterministic times. Thus, to incorporate this uncertainty, we present a method for using the MILP with "overlap discounted rolling planning horizon". The approach is based on valuing near-term decision results more than future ones. We develop a model of taxitime uncertainty based on real-world data, and then compare the baseline FCFS delays with delays using the above MILP in a simple rolling-horizon method and in the overlap discounted scheme.
Author
INTEGERS; AIRPORTS; SCHEDULING; CONTROLLERS; AIR TRANSPORTATION; RUNWAYS
20090035826 SGT, Inc., Moffett Field, CA, United States
Peer-to-Peer Planning for Space Mission Control
Barreiro, Javier; Jones, Grailing, Jr.; Schaffer, Steve; March 07, 2009; In English; IEEE Aerospace Conference, 7-14 Mar. 2009, Big Sky, MT, United States; Original contains black and white illustrations
Contract(s)/Grant(s): NNA04AA18B
Report No.(s): ARC-E-DAA-TN330; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035826
Planning and scheduling for space operations entails the development of applications that embed intimate domain knowledge of distinct areas of mission control, while allowing for significant collaboration among them. The separation is useful because of differences in the planning problem, solution methods, and frequencies of replanning that arise in the different disciplines. For example, planning the activities of human spaceflight crews requires some reasoning about all spacecraft resources at timescales of minutes or seconds, and is subject to considerable volatility. Detailed power planning requires managing the complex interplay of power consumption and production, involves very different classes of constraints and preferences, but once plans are generated they are relatively stable.
Author
MISSION PLANNING; SPACE MISSIONS; SPACE FLIGHT; ENERGY CONSUMPTION; SCHEDULING
20090035829 Stinger Ghaffarin Technologies, Inc., Moffett Field, CA, United States
A Simple and Efficient Computational Approach to Chafed Cable Time-Domain Reflectometry Signature Prediction
Kowalski, Marc Edward; March 08, 2009; In English; Annual Review of Progress in Applied Computational Electromagnetics, 8-12 Mar. 2009, Monterey, CA, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): NNA08CG83C
Report No.(s): ARC-E-DAA-TN261; No Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035829
A method for the prediction of time-domain signatures of chafed coaxial cables is presented. The method is quasi-static in nature, and is thus efficient enough to be included in inference and inversion routines. Unlike previous models proposed, no restriction on the geometry or size of the chafe is required in the present approach. The model is validated and its speed is illustrated via comparison to simulations from a commercial, three-dimensional electromagnetic simulator.
Author
COAXIAL CABLES; OPTICAL MEASUREMENT; PREDICTION ANALYSIS TECHNIQUES; TIME DOMAIN ANALYSIS; SIGNATURES
20090035830 NASA Ames Research Center, Moffett Field, CA, United States
A Distributed Prognostic Health Management Architecture
Bhaskar, Saha; Saha, Sankalita; Goebel, Kai; April 28, 2009; In English; MFPT 2009, 28-30 Apr. 2009, Dayton, OH, United States; Original contains color illustrations
Report No.(s): ARC-E-DAA-TN401; No Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035830
This paper introduces a generic distributed prognostic health management (PHM) architecture with specific application to the electrical power systems domain. Current state-of-the-art PHM systems are mostly centralized in nature, where all the processing is reliant on a single processor. This can lead to loss of functionality in case of a crash of the central processor or monitor. Furthermore, with increases in the volume of sensor data as well as the complexity of algorithms, traditional centralized systems become unsuitable for successful deployment, and efficient distributed architectures are required. A distributed architecture though, is not effective unless there is an algorithmic framework to take advantage of its unique abilities. The health management paradigm envisaged here incorporates a heterogeneous set of system components monitored by a varied suite of sensors and a particle filtering (PF) framework that has the power and the flexibility to adapt to the different diagnostic and prognostic needs. Both the diagnostic and prognostic tasks are formulated as a particle filtering problem in order to explicitly represent and manage uncertainties; however, typically the complexity of the prognostic routine is higher than the computational power of one computational element ( CE). Individual CEs run diagnostic routines until the system variable being monitored crosses beyond a nominal threshold, upon which it coordinates with other networked CEs to run the prognostic routine in a distributed fashion. Implementation results from a network of distributed embedded devices monitoring a prototypical aircraft electrical power system are presented, where the CEs are Sun Microsystems Small Programmable Object Technology (SPOT) devices.
Author
DISTRIBUTED PARAMETER SYSTEMS; COORDINATES; CENTRAL PROCESSING UNITS; ALGORITHMS; DEPLOYMENT
20090035831 California Univ., Santa Cruz, CA, United States
Design Analysis of Corridors-in-the-Sky
Xue, Min; August 10, 2008; In English; Guidance, Navigation, and control Conference (GN&C) 2009, 10-13 Aug. 2009, Chicago, IL, United States; Original contains color and black and white illustrations
Report No.(s): ARC-E-DAA-TN381; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035831
Corridors-in-the-sky or tubes is one of new concepts in dynamic airspace configuration. It accommodates high density traffic, which has similar trajectories. Less air traffic controllers workload is expected than classic airspaces, thus, corridors-in-the-sky may increase national airspace capacity and reduce flight delays. To design corridors-in-the-sky, besides identifying their locations, their utilization, altitudes, and impacts on remaining system need to be analyzed. This paper chooses one tube candidate and presents analyses of spatial and temporal utilization of the tube, the impact on the remaining traffic, and the potential benefit caused by off-loading the traffic from underlying sectors. Fundamental issues regarding to the benefits have been also clarified. Methods developed to assist the analysis are described. Analysis results suggest dynamic tubes in terms of varied utilizations during different time periods. And it is found that combined lane options would be a good choice to lower the impact on non-tube users. Finally, it shows significant reduction of peak aircraft count in underlying sectors with only one tube enabled.
Author
AIRSPACE; POSITION (LOCATION); AIR TRAFFIC CONTROLLERS (PERSONNEL); DESIGN ANALYSIS; TRAJECTORIES; AIR TRAFFIC
20090035832 NASA Ames Research Center, Moffett Field, CA, United States
Carbon Nanotube Based Chemical Sensors for Space and Terrestrial Applications
Li, Jing; Lu, Yijiang; May 24, 2009; In English; Electrochemical Society Spring Meeting 2009, 24-29 May 2009, San Francisco, CA, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): WBS 999574.01.02.01.01
Report No.(s): ARC-E-DAA-TN452; Copyright; Avail.: CASI: A02, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035832
A nanosensor technology has been developed using nanostructures, such as single walled carbon nanotubes (SWNTs), on a pair of interdigitated electrodes (IDE) processed with a silicon-based microfabrication and micromachining technique. The IDE fingers were fabricated using photolithography and thin film metallization techniques. Both in-situ growth of nanostructure materials and casting of the nanostructure dispersions were used to make chemical sensing devices. These sensors have been exposed to nitrogen dioxide, acetone, benzene, nitrotoluene, chlorine, and ammonia in the concentration range of ppm to ppb at room temperature. The electronic molecular sensing of carbon nanotubes in our sensor platform can be understood by intra- and inter-tube electron modulation in terms of charge transfer mechanisms. As a result of the charge transfer, the conductance of p-type or hole-richer SWNTs in air will change. Due to the large surface area, low surface energy barrier and high thermal and mechanical stability, nanostructured chemical sensors potentially can offer higher sensitivity, lower power consumption and better robustness than the state-of-the-art systems, which make them more attractive for defense and space applications. Combined with MEMS technology, light weight and compact size sensors can be made in wafer scale with low cost. Additionally, a wireless capability of such a sensor chip can be used for networked mobile and fixed-site detection and warning systems for military bases, facilities and battlefield areas.
Author
NANOSTRUCTURES (DEVICES); CARBON NANOTUBES; CHARGE TRANSFER; ELECTRODES; DETECTION; WARNING SYSTEMS; THERMAL STABILITY; MICROMACHINING; MICROELECTROMECHANICAL SYSTEMS
20090035833 NASA Ames Research Center, Moffett Field, CA, United States
Assessment of the State of the Art of Ultra High Temperature Ceramics
Johnson, Sylvia; Gasch, Matt; Stackpoole, Mairead; October 12, 2009; In English; 16th AIAA/DLR/DGLR International Space Planes and Hypersonic Systems and Technologies Conference, 12-16 Ict, 2009, Bremen, Germany; Original contains black and white illustrations
Contract(s)/Grant(s): NNA04BC25C
Report No.(s): ARC-E-DAA-TN486; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035833
Ultra High Temperature Ceramics (UHTCs) are a family of materials that includes the borides, carbides and nitrides of hafnium-, zirconium- and titanium-based systems. UHTCs are famous for possessing some of the highest melting points of known materials. In addition, they are very hard, have good wear resistance, mechanical strength, and relatively high thermal conductivities (compared to other ceramic materials). Because of these attributes, UHTCs are ideal for thermal protection systems, especially those that require chemical and structural stability at extremely high operating temperatures. UHTCs have the potential to revolutionize the aerospace industry by enabling the development of sharp hypersonic vehicles or atmospheric entry probes capable of the most extreme entry conditions.
Author
CERAMICS; HIGH TEMPERATURE; BORIDES; MELTING POINTS; HAFNIUM; ZIRCONIUM; TITANIUM; WEAR RESISTANCE
20090035867 NASA Ames Research Center, Moffett Field, CA, United States
SMART Rotor Development and Wind-Tunnel Test
Lau, Benton H.; Straub, Friedrich; Anand, V. R.; Birchette, Terry; September 14, 2009; In English; 35th European Rotorcraft Forum, 22-25 Sep, 2998, Hamburg, Germany; Original contains color illustrations
Report No.(s): ARC-E-DAA-TN453; 747; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035867
Boeing and a team from Air Force, NASA, Army, Massachusetts Institute of Technology, University of California at Los Angeles, and University of Maryland have successfully completed a wind-tunnel test of the smart material actuated rotor technology (SMART) rotor in the 40- by 80-foot wind-tunnel of the National Full-Scale Aerodynamic Complex at NASA Ames Research Center, figure 1. The SMART rotor is a full-scale, five-bladed bearingless MD 900 helicopter rotor modified with a piezoelectric-actuated trailing-edge flap on each blade. The development effort included design, fabrication, and component testing of the rotor blades, the trailing-edge flaps, the piezoelectric actuators, the switching power amplifiers, the actuator control system, and the data/power system. Development of the smart rotor culminated in a whirl-tower hover test which demonstrated the functionality, robustness, and required authority of the active flap system. The eleven-week wind tunnel test program evaluated the forward flight characteristics of the active-flap rotor, gathered data to validate state-of-the-art codes for rotor noise analysis, and quantified the effects of open- and closed-loop active-flap control on rotor loads, noise, and performance. The test demonstrated on-blade smart material control of flaps on a full-scale rotor for the first time in a wind tunnel. The effectiveness and the reliability of the flap actuation system were successfully demonstrated in more than 60 hours of wind-tunnel testing. The data acquired and lessons learned will be instrumental in maturing this technology and transitioning it into production. The development effort, test hardware, wind-tunnel test program, and test results will be presented in the full paper.
Author
BEARINGLESS ROTORS; ROTARY WINGS; ROTOR AERODYNAMICS; SMART MATERIALS; HORIZONTAL FLIGHT; FLIGHT CHARACTERISTICS; ACTIVE CONTROL; FEEDBACK CONTROL
20090035870 NASA Ames Research Center, Moffett Field, CA, United States
Highly Scalable Matching Pursuit Signal Decomposition Algorithm
Christensen, Daniel; Das, Santanu; Srivastava, Ashok N.; September 9, 2009; In English; International Workshop on Structural Health Monitoring, 9-11 Sep. 2009, Stanford, CA, United States; Original contains color and black and white illustrations
Contract(s)/Grant(s): NAS2-03144
Report No.(s): ARC-E-DAA-TN462; Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035870
Matching Pursuit Decomposition (MPD) is a powerful iterative algorithm for signal decomposition and feature extraction. MPD decomposes any signal into linear combinations of its dictionary elements or atoms . A best fit atom from an arbitrarily defined dictionary is determined through cross-correlation. The selected atom is subtracted from the signal and this procedure is repeated on the residual in the subsequent iterations until a stopping criterion is met. The reconstructed signal reveals the waveform structure of the original signal. However, a sufficiently large dictionary is required for an accurate reconstruction; this in return increases the computational burden of the algorithm, thus limiting its applicability and level of adoption. The purpose of this research is to improve the scalability and performance of the classical MPD algorithm. Correlation thresholds were defined to prune insignificant atoms from the dictionary. The Coarse-Fine Grids and Multiple Atom Extraction techniques were proposed to decrease the computational burden of the algorithm. The Coarse-Fine Grids method enabled the approximation and refinement of the parameters for the best fit atom. The ability to extract multiple atoms within a single iteration enhanced the effectiveness and efficiency of each iteration. These improvements were implemented to produce an improved Matching Pursuit Decomposition algorithm entitled MPD++. Disparate signal decomposition applications may require a particular emphasis of accuracy or computational efficiency. The prominence of the key signal features required for the proper signal classification dictates the level of accuracy necessary in the decomposition. The MPD++ algorithm may be easily adapted to accommodate the imposed requirements. Certain feature extraction applications may require rapid signal decomposition. The full potential of MPD++ may be utilized to produce incredible performance gains while extracting only slightly less energy than the standard algorithm. When the utmost accuracy must be achieved, the modified algorithm extracts atoms more conservatively but still exhibits computational gains over classical MPD. The MPD++ algorithm was demonstrated using an over-complete dictionary on real life data. Computational times were reduced by factors of 1.9 and 44 for the emphases of accuracy and performance, respectively. The modified algorithm extracted similar amounts of energy compared to classical MPD. The degree of the improvement in computational time depends on the complexity of the data, the initialization parameters, and the breadth of the dictionary. The results of the research confirm that the three modifications successfully improved the scalability and computational efficiency of the MPD algorithm. Correlation Thresholding decreased the time complexity by reducing the dictionary size. Multiple Atom Extraction also reduced the time complexity by decreasing the number of iterations required for a stopping criterion to be reached. The Course-Fine Grids technique enabled complicated atoms with numerous variable parameters to be effectively represented in the dictionary. Due to the nature of the three proposed modifications, they are capable of being stacked and have cumulative effects on the reduction of the time complexity.
Author
ALGORITHMS; DECOMPOSITION; EXTRACTION; ULTRASONICS; SIGNAL ANALYSIS; PATTERN RECOGNITION; ACCURACY
20090035873 NASA, Washington, DC, United States
NASA Tech Briefs, October 2009
October 2009; In English; Original contains color illustrations
Copyright; Avail.: CASI: A03, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035873
Topics covered include: Light-Driven Polymeric Bimorph Actuators; Guaranteeing Failsafe Operation of Extended-Scene Shack-Hartmann Wavefront Sensor Algorithm; Cloud Water Content Sensor for Sounding Balloons and Small UAVs; Pixelized Device Control Actuators for Large Adaptive Optics; T-Slide Linear Actuators; G4FET Implementations of Some Logic Circuits; Electrically Variable or Programmable Nonvolatile Capacitors; System for Automated Calibration of Vector Modulators; Complementary Paired G4FETs as Voltage-Controlled NDR Device; Three MMIC Amplifiers for the 120-to-200 GHz Frequency Band; Low-Noise MMIC Amplifiers for 120 to 180 GHz; Using Ozone To Clean and Passivate Oxygen-Handling Hardware; Metal Standards for Waveguide Characterization of Materials; Two-Piece Screens for Decontaminating Granular Material; Mercuric Iodide Anticoincidence Shield for Gamma-Ray Spectrometer; Improved Method of Design for Folding Inflatable Shells; Ultra-Large Solar Sail; Cooperative Three-Robot System for Traversing Steep Slopes; Assemblies of Conformal Tanks; Microfluidic Pumps Containing Teflon[Trademark] AF Diaphragms; Transparent Conveyor of Dielectric Liquids or Particles; Multi-Cone Model for Estimating GPS Ionospheric Delays; High-Sensitivity GaN Microchemical Sensors; On the Divergence of the Velocity Vector in Real-Gas Flow; Progress Toward a Compact, Highly Stable Ion Clock; Instruments for Imaging from Far to Near; Reflectors Made from Membranes Stretched Between Beams; Integrated Risk and Knowledge Management Program -- IRKM-P; LDPC Codes with Minimum Distance Proportional to Block Size; Constructing LDPC Codes from Loop-Free Encoding Modules; MMICs with Radial Probe Transitions to Waveguides; Tests of Low-Noise MMIC Amplifier Module at 290 to 340 GHz; and Extending Newtonian Dynamics to Include Stochastic Processes.
Author
ADAPTIVE OPTICS; WAVEGUIDES; RISK MANAGEMENT; ACTUATORS; DECONTAMINATION; OZONE; CALIBRATING; ELECTRIC POTENTIAL; GLOBAL POSITIONING SYSTEM; GAMMA RAY SPECTROMETERS; INTEGRATED CIRCUITS
20090035874 DxRay, Inc., United States
Mercuric Iodide Anticoincidence Shield for Gamma-Ray Spectrometer
Hartsough, Neal; Iwanczyk, Jan; NASA Tech Briefs, October 2009; October 2009; pp. 1; In English
Report No.(s): GSC-15635-1; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035874
http://www.techbriefs.com/component/content/article/5770
A film-growth process was developed for polycrystalline mercuric iodide that creates cost-effective, large-area detectors for high-energy charged-particle detection. A material, called a barrier film, is introduced onto the substrate before the normal mercuric iodide film growth process. The barrier film improves the quality of the normal film grown and enhances the adhesion between the film and the substrate. The films grown using this improved technique were found to have adequate signal-to-noise properties so that individual high-energy charged -particle interactions could be distinguished from noise, and thus, could be used to provide an anticoincidence veto function as desired.
Author
MERCURY COMPOUNDS; IODIDES; GAMMA RAY SPECTROMETERS; ANTICOINCIDENCE DETECTORS; POLYCRYSTALS; CHARGED PARTICLES; ADHESION
20090035875 California Inst. of Tech., Pasadena, CA, United States
G(sup 4)FET Implementations of Some Logic Circuits
Mojarradi, Mohammad; Akarvardar, Kerem; Cristoleveanu, Sorin; Gentil, Paul; Blalock, Benjamin; Chen, Suhan; NASA Tech Briefs, October 2009; October 2009; pp. 9-1; In English; Original contains color illustrations
Report No.(s): NPO-44007; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035875
http://www.techbriefs.com/component/content/article/5766
Some logic circuits have been built and demonstrated to work substantially as intended, all as part of a continuing effort to exploit the high degrees of design flexibility and functionality of the electronic devices known as G(sup 4)FETs and described below. These logic circuits are intended to serve as prototypes of more complex advanced programmable-logicdevice-type integrated circuits, including field-programmable gate arrays (FPGAs). In comparison with prior FPGAs, these advanced FPGAs could be much more efficient because the functionality of G(sup 4)FETs is such that fewer discrete components are needed to perform a given logic function in G(sup 4)FET circuitry than are needed perform the same logic function in conventional transistor-based circuitry. The underlying concept of using G(sup 4)FETs as building blocks of programmable logic circuitry was also described, from a different perspective, in G(sup 4)FETs as Universal and Programmable Logic Gates (NPO-41698), NASA Tech Briefs, Vol. 31, No. 7 (July 2007), page 44. A G(sup 4)FET can be characterized as an accumulation-mode silicon-on-insulator (SOI) metal oxide/semiconductor field-effect transistor (MOSFET) featuring two junction field-effect transistor (JFET) gates. The structure of a G(sup 4)FET (see Figure 1) is the same as that of a p-channel inversion-mode SOI MOSFET with two body contacts on each side of the channel. The top gate (G1), the substrate emulating a back gate (G2), and the junction gates (JG1 and JG2) can be biased independently of each other and, hence, each can be used to independently control some aspects of the conduction characteristics of the transistor. The independence of the actions of the four gates is what affords the enhanced functionality and design flexibility of G(sup 4)FETs. The present G(sup 4)FET logic circuits include an adjustable-threshold inverter, a real-time-reconfigurable logic gate, and a dynamic random-access memory (DRAM) cell (see Figure 2). The configuration of the adjustable-threshold inverter is similar to that of an ordinary complementary metal oxide semiconductor (CMOS) inverter except that an NMOSFET (a MOSFET having an n-doped channel and a p-doped Si substrate) is replaced by an n-channel G(sup 4)FET
Author
FIELD EFFECT TRANSISTORS; FIELD-PROGRAMMABLE GATE ARRAYS; GATES (CIRCUITS); INTEGRATED CIRCUITS; DOPED CRYSTALS; RANDOM ACCESS MEMORY; METAL OXIDE SEMICONDUCTORS; SOI (SEMICONDUCTORS)
20090035876 NASA Glenn Research Center, Cleveland, OH, United States
Light-Driven Polymeric Bimorph Actuators
Adamovsky, Gregory; Sarkisov, Sergey S.; Curley, Michael J.; NASA Tech Briefs, October 2009; October 2009; pp. ; In English; Original contains color illustrations
Report No.(s): LEW-17473-1; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035876
http://www.techbriefs.com/component/content/article/5755
Light-driven polymeric bimorph actuators are being developed as alternatives to prior electrically and optically driven actuators in advanced, highly miniaturized devices and systems exemplified by microelectromechanical systems (MEMS), micro-electro-optical-mechanical systems (MEOMS), and sensor and actuator arrays in smart structures. These light-driven polymeric bimorph actuators are intended to satisfy a need for actuators that (1) in comparison with the prior actuators, are simpler and less power-hungry; (2) can be driven by low-power visible or mid-infrared light delivered through conventional optic fibers; and (3) are suitable for integration with optical sensors and multiple actuators of the same or different type. The immediate predecessors of the present light-driven polymeric bimorph actuators are bimorph actuators that exploit a photorestrictive effect in lead lanthanum zirconate titanate (PLZT) ceramics. The disadvantages of the PLZT-based actuators are that (1) it is difficult to shape the PLZT ceramics, which are hard and brittle; (2) for actuation, it is necessary to use ultraviolet light (wavelengths < 380 nm), which must be generated by use of high-power, high-pressure arc lamps or lasers; (3) it is difficult to deliver sufficient ultraviolet light through conventional optical fibers because of significant losses in the fibers; (4) the response times of the PLZT actuators are of the order of several seconds unacceptably long for typical applications; and (5) the maximum mechanical displacements of the PLZT-based actuators are limited to those characterized by low strains beyond which PLZT ceramics disintegrate because of their brittleness. The basic element of a light-driven bimorph actuator of the present developmental type is a cantilever beam comprising two layers, at least one of which is a polymer that exhibits a photomechanical effect (see figure). The dominant mechanism of the photomechanical effect is a photothermal one: absorption of light energy causes heating, which, in turn, causes thermal expansion.
Author
ACTUATORS; PHOTOMECHANICAL EFFECT; MICROELECTROMECHANICAL SYSTEMS; ELECTROMAGNETIC ABSORPTION; CERAMICS; ARC LAMPS; ULTRAVIOLET RADIATION; THERMAL EXPANSION; OPTICAL MEASURING INSTRUMENTS; LANTHANUM COMPOUNDS
20090035877 California Inst. of Tech., Pasadena, CA, United States
Cooperative Three-Robot System for Traversing Steep Slopes
Stroupe, Ashley; Huntsberger, Terrance; Aghazarian, Hrand; Younse, Paulo; Garrett, Michael; NASA Tech Briefs, October 2009; October 2009; pp. 19-2; In English; Original contains color illustrations
Report No.(s): NPO-44699; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035877
http://www.techbriefs.com/component/content/article/5779
Teamed Robots for Exploration and Science in Steep Areas (TRESSA) is a system of three autonomous mobile robots that cooperate with each other to enable scientific exploration of steep terrain (slope angles up to 90 ). Originally intended for use in exploring steep slopes on Mars that are not accessible to lone wheeled robots (Mars Exploration Rovers), TRESSA and systems like TRESSA could also be used on Earth for performing rescues on steep slopes and for exploring steep slopes that are too remote or too dangerous to be explored by humans. TRESSA is modeled on safe human climbing of steep slopes, two key features of which are teamwork and safety tethers. Two of the autonomous robots, denoted Anchorbots, remain at the top of a slope; the third robot, denoted the Cliffbot, traverses the slope. The Cliffbot drives over the cliff edge supported by tethers, which are payed out from the Anchorbots (see figure). The Anchorbots autonomously control the tension in the tethers to counter the gravitational force on the Cliffbot. The tethers are payed out and reeled in as needed, keeping the body of the Cliffbot oriented approximately parallel to the local terrain surface and preventing wheel slip by controlling the speed of descent or ascent, thereby enabling the Cliffbot to drive freely up, down, or across the slope. Due to the interactive nature of the three-robot system, the robots must be very tightly coupled. To provide for this tight coupling, the TRESSA software architecture is built on a combination of (1) the multi-robot layered behavior-coordination architecture reported in "An Architecture for Controlling Multiple Robots" (NPO-30345), NASA Tech Briefs, Vol. 28, No. 10 (October 2004), page 65, and (2) the real-time control architecture reported in "Robot Electronics Architecture" (NPO-41784), NASA Tech Briefs, Vol. 32, No. 1 (January 2008), page 28. The combination architecture makes it possible to keep the three robots synchronized and coordinated, to use data from all three robots for decision- making at each step, and to control the physical connections among the robots. In addition, TRESSA (as in prior systems that have utilized this architecture) , incorporates a capability for deterministic response to unanticipated situations from yet another architecture reported in Control Architecture for Robotic Agent Command and Sensing (NPO-43635), NASA Tech Briefs, Vol. 32, No. 10 (October 2008), page 40. Tether tension control is a major consideration in the design and operation of TRESSA. Tension is measured by force sensors connected to each tether at the Cliffbot. The direction of the tension (both azimuth and elevation) is also measured. The tension controller combines a controller to counter gravitational force and an optional velocity controller that anticipates the motion of the Cliffbot. The gravity controller estimates the slope angle from the inclination of the tethers. This angle and the weight of the Cliffbot determine the total tension needed to counteract the weight of the Cliffbot. The total needed tension is broken into components for each Anchorbot. The difference between this needed tension and the tension measured at the Cliffbot constitutes an error signal that is provided to the gravity controller. The velocity controller computes the tether speed needed to produce the desired motion of the Cliffbot. Another major consideration in the design and operation of TRESSA is detection of faults. Each robot in the TRESSA system monitors its own performance and the performance of its teammates in order to detect any system faults and prevent unsafe conditions. At startup, communication links are tested and if any robot is not communicating, the system refuses to execute any motion commands. Prior to motion, the Anchorbots attempt to set tensions in the tethers at optimal levels for counteracting the weight of the Cliffbot; if either Anchorbot fails to reach its optimal tension level within a specified time, it sends message to the other robots and the commanded motion is not executed. If any mechanical error (e.g., stalling of a motor) is detected, the affected robot sends a message triggering stoppage of the current motion. Lastly, messages are passed among the robots at each time step (10 Hz) to share sensor information during operations. If messages from any robot cease for more than an allowable time interval, the other robots detect the communication loss and initiate stoppage.
Author
ROBOTS; ROVING VEHICLES; MARS EXPLORATION; ASCENT; SLOPES; TERRAIN; TETHERING; ESTIMATES; CONTROLLERS; COMMUNICATION NETWORKS; CLIFFS
20090035878 NASA Marshall Space Flight Center, Huntsville, AL, United States
Assemblies of Conformal Tanks
DeLay, Tom; NASA Tech Briefs, October 2009; October 2009; pp. 20-2; In English; Original contains color illustrations
Report No.(s): MFS-32015-1; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035878
http://www.techbriefs.com/component/content/article/5780
Assemblies of tanks having shapes that conform to each other and/or conform to other proximate objects have been investigated for use in storing fuels and oxidizers in small available spaces in upper stages of spacecraft. Such assemblies might also prove useful in aircraft, automobiles, boats, and other terrestrial vehicles in which space available for tanks is limited. The basic concept of using conformal tanks to maximize the utilization of limited space is not new in itself: for example, conformal tanks are used in some automobiles to store windshield -washer liquid and coolant that overflows from radiators. The novelty of the present development lies in the concept of an assembly of smaller conformal tanks, as distinguished from a single larger conformal tank. In an assembly of smaller tanks, it would be possible to store different liquids in different tanks. Even if the same liquid were stored in all the tanks, the assembly would offer an advantage by reducing the mechanical disturbance caused by sloshing of fuel in a single larger tank: indeed, the requirement to reduce sloshing is critical in some applications. The figure shows a prototype assembly of conformal tanks. Each tank was fabricated by (1) copper plating a wax tank mandrel to form a liner and (2) wrapping and curing layers of graphite/epoxy composite to form a shell supporting the liner. In this case, the conformal tank surfaces are flat ones where they come in contact with the adjacent tanks. A band of fibers around the outside binds the tanks together tightly in the assembly, which has a quasi-toroidal shape. For proper functioning, it would be necessary to maintain equal pressure in all the tanks.
Author
STORAGE TANKS; FUELS; OXIDIZERS; COMPOSITE STRUCTURES; GRAPHITE-EPOXY COMPOSITES; SHELLS (STRUCTURAL FORMS); LIQUID SLOSHING; COOLANTS
20090035879 California Inst. of Tech., Pasadena, CA, United States
Reflectors Made from Membranes Stretched Between Beams
Dooley, Jennifer; Dragovan, Mark; Tolomeo, Jason; NASA Tech Briefs, October 2009; October 2009; pp. 2; In English; Original contains color illustrations
Report No.(s): NPO-30571; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035879
http://www.techbriefs.com/component/content/article/5798
Lightweight cylindrical reflectors of a proposed type would be made from reflective membranes stretched between pairs of identically curved and identically oriented end rails. In each such reflector, the curvature of the two beams would define the reflector shape required for the intended application. For example, the beams could be curved to define a reflector of parabolic cross section, so that light incident along the axis of symmetry perpendicular to the cylindrical axis would be focused to a line. In addition, by applying suitable forces to the ends of the beams, one could bend the beams to adjust the reflector surface figure to within a precision of the order of the wavelength of the radiation to be reflected. The figure depicts an example of beams shaped so that in the absence of applied forces, each would be flat on one side and would have a radius of curvature R on the opposite side. Alternatively, the curvature of the reflector-membrane side could be other than circular. In general, the initial curvature would be chosen to optimize the final reflector shape. Then by applying forces F between the beam ends in the positions and orientations shown in the figure, one could bend beams to adjust their shape to a closer approximation of the desired precise circular or noncircular curvature.
Author
REFLECTORS; CYLINDRICAL BODIES; MEMBRANES; SYMMETRY; STRETCHING; PRECISION
20090035880 NASA Kennedy Space Center, Cocoa Beach, FL, United States
Transparent Conveyor of Dielectric Liquids or Particles
Calle, Carlos I.; Mantovani, James G.; NASA Tech Briefs, October 2009; October 2009; pp. 2; In English; Original contains color illustrations
Report No.(s): KSC-12616; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035880
http://www.techbriefs.com/component/content/article/5785
The concept of a transparent conveyor dielectric particles or small has emerged efficient, from solar cells and from This concept of an electrodynamic screen, according electric field is lines. The resulting electrodynamic dielectric particles vicinity surface. In the original dust-removal particles would thus be area. Other potential applications may nanotechnology -- for example, more fluids optical
Derived from text
DIELECTRICS; TRANSPARENCE; CLEANING
20090035881 Houston Univ., Houston, TX, United States
Electrically Variable or Programmable Nonvolatile Capacitors
Shangqing, Liu; NaiJuan, Wu; Ignatieu, Alex; Jianren, Li; NASA Tech Briefs, October 2009; October 2009; pp. 10-1; In English; Original contains color illustrations
Report No.(s): MFS-31960-1; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035881
http://www.techbriefs.com/component/content/article/5773
Electrically variable or programmable capacitors based on the unique properties of thin perovskite films are undergoing development. These capacitors show promise of overcoming two important deficiencies of prior electrically programmable capacitors: Unlike in the case of varactors, it is not necessary to supply power continuously to make these capacitors retain their capacitance values. Hence, these capacitors may prove useful as components of nonvolatile analog and digital electronic memories. Unlike in the case of ferroelectric capacitors, it is possible to measure the capacitance values of these capacitors without changing the values. In other words, whereas readout of ferroelectric capacitors is destructive, readout of these capacitors can be nondestructive. A capacitor of this type is a simple two terminal device. It includes a thin film of a suitable perovskite as the dielectric layer, sandwiched between two metal or metal oxide electrodes (for example, see Figure 1). The utility of this device as a variable capacitor is based on a phenomenon, known as electrical-pulse-induced capacitance (EPIC), that is observed in thin perovskite films and especially in those thin perovskite films that exhibit the colossal magnetoresistive (CMR) effect. In EPIC, the application of one or more electrical pulses that exceed a threshold magnitude (typically somewhat less than 1 V) gives rise to a nonvolatile change in capacitance. The change in capacitance depends on the magnitude duration, polarity, and number of pulses. It is not necessary to apply a magnetic field or to cool the device below (or heat it above) room temperature to obtain EPIC. Examples of suitable CMR perovskites include Pr(1-x)Ca(x)MnO3, La(1-x)S-r(x)MnO3,and Nb(1-x)Ca(x)MnO3. Figure 2 is a block diagram showing an EPIC capacitor connected to a circuit that can vary the capacitance, measure the capacitance, and/or measure the resistance of the capacitor.
Derived from text
CAPACITANCE; CAPACITORS; MAGNETORESISTIVITY; FABRICATION; VARACTOR DIODES
20090035882 Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA, United States
On the Divergence of the Velocity Vector in Real-Gas Flow
Bellan, Josette; NASA Tech Briefs, October 2009; October 2009; pp. 2; In English
Report No.(s): NPO-46113; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035882
http://www.techbriefs.com/component/content/article/5789
A theoretical study was performed addressing the degree of applicability or inapplicability, to a real gas, of the occasionally stated belief that for an ideal gas, incompressibility is synonymous with a zero or very low Mach number. The measure of compressibility used in this study is the magnitude of the divergence of the flow velocity vector [V(bar) (raised dot) u (where u is the flow velocity)]. The study involves a mathematical derivation that begins with the governing equations of flow and involves consideration of equations of state, thermodynamics, and fluxes of heat, mass, and the affected molecular species. The derivation leads to an equation for the volume integral of (V(bar) (raised dot) u)(sup 2) that indicates contributions of several thermodynamic, hydrodynamic, and species-flux effects to compressibility and reveals differences between real and ideal gases. An analysis of the equation leads to the conclusion that for a real gas, incompressibility is not synonymous with zero or very small Mach number. Therefore, it is further concluded, the contributions to compressibility revealed by the derived equation should be taken into account in simulations of real-gas flows.
Author
DIVERGENCE; FLOW VELOCITY; GAS FLOW; REAL GASES; VECTORS (MATHEMATICS)
20090035883 California Inst. of Tech., Pasadena, CA, United States
Extending Newtonian Dynamics to Include Stochastic Processes
Zak, Michail; NASA Tech Briefs, October 2009; October 2009; pp. 3; In English
Report No.(s): NPO-45594; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035883
http://www.techbriefs.com/component/content/article/5795
A paper presents further results of continuing research reported in several previous NASA Tech Briefs articles, the two most recent being Stochastic Representations of Chaos Using Terminal Attractors (NPO-41519), [Vol. 30, No. 5 (May 2006), page 57] and Physical Principle for Generation of Randomness (NPO-43822) [Vol. 33, No. 5 (May 2009), page 56]. This research focuses upon a mathematical formalism for describing post-instability motions of a dynamical system characterized by exponential divergences of trajectories leading to chaos (including turbulence as a form of chaos). The formalism involves fictitious control forces that couple the equations of motion of the system with a Liouville equation that describes the evolution of the probability density of errors in initial conditions. These stabilizing forces create a powerful terminal attractor in probability space that corresponds to occurrence of a target trajectory with probability one. The effect in configuration space (ordinary three-dimensional space as commonly perceived) is to suppress exponential divergences of neighboring trajectories without affecting the target trajectory. As a result, the post-instability motion is represented by a set of functions describing the evolution of such statistical quantities as expectations and higher moments, and this representation is stable.
Author
STOCHASTIC PROCESSES; NEWTON METHODS; TRAJECTORIES; LIOUVILLE EQUATIONS; DIVERGENCE; EQUATIONS OF MOTION; TURBULENCE
20090035884 Illinois Univ., Urbana-Champaign, IL, United States
Ultra-Large Solar Sail
Burton, Rodney; Coverstone, Victoria; NASA Tech Briefs, October 2009; October 2009; pp. 1; In English
Report No.(s): MFS-32524-1; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035884
http://www.techbriefs.com/component/content/article/5778
UltraSail is a next-generation ultra-large (km2 class) sail system. Analysis of the launch, deployment, stabilization, and control of these sails shows that high-payload-mass fractions for interplanetary and deep-space missions are possible. UltraSail combines propulsion and control systems developed for formation-flying microsatellites with a solar sail architecture to achieve controllable sail areas approaching 1 km2. Electrically conductive CP-1 polyimide film results in sail subsystem area densities as low as 5 g/m2. UltraSail produces thrust levels many times those of ion thrusters used for comparable deep-space missions. The primary innovation involves the near-elimination of sail-supporting structures by attaching each blade tip to a formation- flying microsatellite, which deploys the sail and then articulates the sail to provide attitude control, including spin stabilization and precession of the spin axis. These microsatellite tips are controlled by microthrusters for sail-film deployment and mission operations. UltraSail also avoids the problems inherent in folded sail film, namely stressing, yielding, or perforating, by storing the film in a roll for launch and deployment. A 5-km long by 2 micrometer thick film roll on a mandrel with a 1 m circumference (32 cm diameter) has a stored thickness of 5 cm. A 5 m-long mandrel can store a film area of 25,000 m2, and a four-blade system has an area of 0.1 sq km.
Author
SOLAR SAILS; PROPULSION SYSTEM PERFORMANCE; DEPLOYMENT; SPIN STABILIZATION; PROPULSION SYSTEM CONFIGURATIONS; SPACECRAFT PROPULSION; MICROROCKET ENGINES; ATTITUDE CONTROL; ION ENGINES
20090035885 NASA Johnson Space Center, Houston, TX, United States
Using Ozone To Clean and Passivate Oxygen-Handling Hardware
Torrance, Paul; Biesinger, Paul; NASA Tech Briefs, October 2009; October 2009; pp. 1; In English
Report No.(s): MSC-23290-1; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035885
http://www.techbriefs.com/component/content/article/5775
A proposed method of cleaning, passivating, and verifying the cleanliness of oxygen-handling hardware would extend the established art of cleaning by use of ozone. As used here, "cleaning" signifies ridding all exposed surfaces of combustible (in particular, carbon-based) contaminants. The method calls for exposing the surfaces of the hardware to ozone while monitoring the ozone effluent for carbon dioxide. The ozone would passivate the hardware while oxidizing carbon-based residues, converting the carbon in them to carbon dioxide. The exposure to ozone would be continued until no more carbon dioxide was detected, signifying that cleaning and passivation were complete.
Author
OZONE; CONTAMINANTS; PASSIVITY; OXIDATION; EFFLUENTS; CLEANING; CARBON DIOXIDE; RESIDUES
20090035886 California Inst. of Tech., Pasadena, CA, United States
Guaranteeing Failsafe Operation of Extended-Scene Shack-Hartmann Wavefront Sensor Algorithm
Sidick, Erikin; NASA Tech Briefs, October 2009; October 2009; pp. ; In English
Report No.(s): NPO-46582; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035886
http://www.techbriefs.com/component/content/article/5756
A Shack-Hartmann sensor (SHS) is an optical instrument consisting of a lenslet array and a camera. It is widely used for wavefront sensing in optical testing and astronomical adaptive optics. The camera is placed at the focal point of the lenslet array and points at a star or any other point source. The image captured is an array of spot images. When the wavefront error at the lenslet array changes, the position of each spot measurably shifts from its original position. Determining the shifts of the spot images from their reference points shows the extent of the wavefront error. An adaptive cross-correlation (ACC) algorithm has been developed to use scenes as well as point sources for wavefront error detection. Qualifying an extended scene image is often not an easy task due to changing conditions in scene content, illumination level, background, Poisson noise, read-out noise, dark current, sampling format, and field of view. The proposed new technique based on ACC algorithm analyzes the effects of these conditions on the performance of the ACC algorithm and determines the viability of an extended scene image. If it is viable, then it can be used for error correction; if it is not, the image fails and will not be further processed. By potentially testing for a wide variety of conditions, the algorithm s accuracy can be virtually guaranteed. In a typical application, the ACC algorithm finds image shifts of more than 500 Shack-Hartmann camera sub-images relative to a reference sub -image or cell when performing one wavefront sensing iteration. In the proposed new technique, a pair of test and reference cells is selected from the same frame, preferably from two well-separated locations. The test cell is shifted by an integer number of pixels, say, for example, from m= -5 to 5 along the x-direction by choosing a different area on the same sub-image, and the shifts are estimated using the ACC algorithm. The same is done in the y-direction. If the resulting shift estimate errors are less than a pre-determined threshold (e.g., 0.03 pixel), the image is accepted. Otherwise, it is rejected.
Author
CAMERAS; ADAPTIVE OPTICS; POINT SOURCES; FIELD OF VIEW; PIXELS; ERROR ANALYSIS; DARK CURRENT
20090035887 Analex Corp., United States
Metal Standards for Waveguide Characterization of Materials
Lambert, Kevin M.; Kory, Carol L.; NASA Tech Briefs, October 2009; October 2009; pp. 15-1; In English; Original contains color illustrations
Report No.(s): LEW-18137-1; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035887
http://www.techbriefs.com/component/content/article/5777
Rectangular-waveguide inserts that are made of non-ferromagnetic metals and are sized and shaped to function as notch filters have been conceived as reference standards for use in the rectangular- waveguide method of characterizing materials with respect to such constitutive electromagnetic properties as permittivity and permeability. Such standards are needed for determining the accuracy of measurements used in the method, as described below. In this method, a specimen of a material to be characterized is cut to a prescribed size and shape and inserted in a rectangular- waveguide test fixture, wherein the specimen is irradiated with a known source signal and detectors are used to measure the signals reflected by, and transmitted through, the specimen. Scattering parameters [also known as "S" parameters (S11, S12, S21, and S22)] are computed from ratios between the transmitted and reflected signals and the source signal. Then the permeability and permittivity of the specimen material are derived from the scattering parameters. Theoretically, the technique for calculating the permeability and permittivity from the scattering parameters is exact, but the accuracy of the results depends on the accuracy of the measurements from which the scattering parameters are obtained. To determine whether the measurements are accurate, it is necessary to perform comparable measurements on reference standards, which are essentially specimens that have known scattering parameters. To be most useful, reference standards should provide the full range of scattering-parameter values that can be obtained from material specimens. Specifically, measurements of the backscattering parameter (S11) from no reflection to total reflection and of the forward-transmission parameter (S21) from no transmission to total transmission are needed. A reference standard that functions as a notch (band-stop) filter can satisfy this need because as the signal frequency is varied across the frequency range for which the filter is designed, the scattering parameters vary over the ranges of values between the extremes of total reflection and total transmission. A notch-filter reference standard in the form of a rectangular-waveguide insert that has a size and shape similar to that of a material specimen is advantageous because the measurement configuration used for the reference standard can be the same as that for a material specimen. Typically a specimen is a block of material that fills a waveguide cross-section but occupies only a small fraction of the length of the waveguide. A reference standard of the present type (see figure) is a metal block that fills part of a waveguide cross section and contains a slot, the long dimension of which can be chosen to tailor the notch frequency to a desired value. The scattering parameters and notch frequency can be estimated with high accuracy by use of commercially available electromagnetic-field-simulating software. The block can be fabricated to the requisite precision by wire electrical-discharge machining. In use, the accuracy of measurements is determined by comparison of (1) the scattering parameters calculated from the measurements with (2) the scattering parameters calculated by the aforementioned software.
Author
METALS; WAVEGUIDES; STANDARDS; SCATTERING; PERMEABILITY; ELECTROMAGNETIC PROPERTIES; BACKSCATTERING; ELECTROMAGNETIC FIELDS; FREQUENCY RANGES; RECTANGULAR WAVEGUIDES
20090035888 California Inst. of Tech., Pasadena, CA, United States
Microfluidic Pumps Containing Teflon [Trademark] AF Diaphragms
Willis, Peter; White, Victor; Grunthaner, Frank; Ikeda, Mike; Mathies, Richard A.; NASA Tech Briefs, October 2009; October 2009; pp. 2; In English
Report No.(s): NPO-44482; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035888
http://www.techbriefs.com/component/content/article/5783
Microfluidic pumps and valves based on pneumatically actuated diaphragms made of Teflon AF polymers are being developed for incorporation into laboratory-on-a-chip devices that must perform well over temperature ranges wider than those of prior diaphragm-based microfluidic pumps and valves. Other potential applications include implanted biomedical microfluidic devices, wherein the biocompatability of Teflon AF polymers would be highly advantageous. These pumps and valves have been demonstrated to function stably after cycling through temperatures from -125 to 120 C. These pumps and valves are intended to be successors to similar prior pumps and valves containing diaphragms made of polydimethylsiloxane (PDMS) [commonly known as silicone rubber]. The PDMS-containing valves ae designed to function stably only within the temperature range from 5 to 80 C. Undesirably, PDMS membranes are somwehat porous and retain water. PDMS is especially unsuitable for use at temperatures below 0 C because the formation of ice crystals increases porosity and introduces microshear.
Author
BIOINSTRUMENTATION; METHYL POLYSILOXANES; MICROFLUIDIC DEVICES; SILICONE RUBBER; FLUOROPOLYMERS
20090035889 NASA, Washington, DC, United States
Integrated Risk and Knowledge Management Program -- IRKM-P
Lengyel, David M.; NASA Tech Briefs, October 2009; October 2009; pp. 2; In English
Report No.(s): HQN-11315-1; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035889
http://www.techbriefs.com/component/content/article/5790
The NASA Exploration Systems Mission Directorate (ESMD) IRKM-P tightly couples risk management and knowledge management processes and tools to produce an effective "modern" work environment. IRKM-P objectives include: (1) to learn lessons from past and current programs (Apollo, Space Shuttle, and the International Space Station); (2) to generate and share new engineering design, operations, and management best practices through preexisting Continuous Risk Management (CRM) procedures and knowledge-management practices; and (3) to infuse those lessons and best practices into current activities. The conceptual framework of the IRKM-P is based on the assumption that risks highlight potential knowledge gaps that might be mitigated through one or more knowledge management practices or artifacts. These same risks also serve as cues for collection of knowledge particularly, knowledge of technical or programmatic challenges that might recur.
Author
RISK MANAGEMENT; ENGINEERING MANAGEMENT; SPACE SHUTTLES; PROCEDURES; RISK
20090035890 California Inst. of Tech., Pasadena, CA, United States
Low-Noise MMIC Amplifiers for 120 to 180 GHz
Pukala, David; Samoska, Lorene; Peralta, Alejandro; Bayuk, Brian; Grundbacher, Ron; Oliver, Patricia; Cavus, Abdullah; Liu, Po-Hsin; NASA Tech Briefs, October 2009; October 2009; pp. 1; In English; Original contains color illustrations
Report No.(s): NPO-42783; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035890
http://www.techbriefs.com/component/content/article/5760
Three-stage monolithic millimeter-wave integrated-circuit (MMIC) amplifiers capable of providing useful amounts of gain over the frequency range from 120 to 180 GHz have been developed as prototype low-noise amplifiers (LNAs) to be incorporated into instruments for sensing cosmic microwave background radiation. There are also potential uses for such LNAs in electronic test equipment, passive millimeter- wave imaging systems, radar receivers, communication receivers, and systems for detecting hidden weapons. The main advantage afforded by these MMIC LNAs, relative to prior MMIC LNAs, is that their coverage of the 120-to-180-GHz frequency band makes them suitable for reuse in a wider variety of applications without need to redesign them. Each of these MMIC amplifiers includes InP transistors and coplanar waveguide circuitry on a 50- mthick chip (see Figure 1). Coplanar waveguide transmission lines are used for both applying DC bias and matching of input and output impedances of each transistor stage. Via holes are incorporated between top and bottom ground planes to suppress propagation of electromagnetic modes in the substrate. On the basis of computational simulations, each of these amplifiers was expected to operate with a small-signal gain of 14 dB and a noise figure of 4.3 dB. At the time of writing this article, measurements of noise figures had not been reported, but on-chip measurements had shown gains approaching their simulated values (see Figure 2).
Author
COSMIC MICROWAVE BACKGROUND RADIATION; MICROWAVE CIRCUITS; INTEGRATED CIRCUITS; LOW NOISE; MICROWAVE AMPLIFIERS; FREQUENCY RANGES; TRANSISTORS; WAVEGUIDES
20090035891 Defense Advanced Research Projects Agency, Arlington, VA, United States
MMICs with Radial Probe Transitions to Waveguides
Samoska, Lorene; Chattopadhyay, Goutam; Pukala, David; Soria, Mary; Fung, King Man; Gaier, Todd; Radisic, Vesna; Lai, Richard; NASA Tech Briefs, October 2009; October 2009; pp. 3; In English
Report No.(s): NPO-45460; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035891
http://www.techbriefs.com/component/content/article/5793
A document presents an update on the innovation reported in Integrated Radial Probe Transition From MMIC to Waveguide (NPO-43957), NASA Tech Briefs Vol. 31, No. 5 (May 2007), page 38. To recapitulate: To enable operation or testing of a monolithic microwave integrated circuit (MMIC), it is necessary to mount the MMIC in a waveguide package that typically has cross-sectional waveguide dimensions of the order of a few hundred microns. A radial probe transition between an MMIC operating at 340 GHz and a waveguide had been designed (but not yet built and tested) to be fabricated as part of a monolithic unit that would include the MMIC. The radial probe could readily be integrated with an MMIC amplifier because the design provided for fabrication of the transition on a substrate of the same material (InP) and thickness (50 m) typical of substrates of MMICs that can operate above 300 GHz. As illustrated in the updated document by drawings, photographs, and plots of test data, the concept has now been realized by designing, fabricating, and testing several MMIC/radial- probe integrated-circuit chips and designing and fabricating a waveguide package to contain each chip.
Author
MICROWAVE CIRCUITS; INTEGRATED CIRCUITS; CHIPS; WAVEGUIDES
20090035892 California Inst. of Tech., Pasadena, CA, United States
Tests of Low-Noise MMIC Amplifier Module at 290 to 340 GHz
Gaier, Todd; Samoska, Lorene; Fung, King Man; Deal, William; Mei, Xiaobing; Lai, Richard; NASA Tech Briefs, October 2009; October 2009; pp. 3; In English
Report No.(s): NPO-45461; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035892
http://www.techbriefs.com/component/content/article/5794
A document presents data from tests of a low-noise amplifier module operating in the frequency range from 290 to 340 GHz said to be the highest-frequency low-noise, solid-state amplifier ever developed. The module comprised a three-stage monolithic microwave integrated circuit (MMIC) amplifier integrated with radial probe MMIC/waveguide transitions and contained in a compact waveguide package, all according to the concepts described in the immediately preceding article and in the referenced prior article, "Integrated Radial Probe Transition From MMIC to Waveguide" (NPO-43957), NASA Tech Briefs Vol. 31, No. 5 (May 2007), page 38. The tests included measurements by the Y-factor method, in which noise figures are measured repeatedly with an input noise source alternating between an "on" (hot-load) condition and an "off" (cold-load) condition. (The Y factor is defined as the ratio between the "on" and "off" noise power levels.) The test results showed that, among other things, the module exhibited a minimum noise figure of about 8.7 dB at 325 GHz and that the gain at that frequency under the bias conditions that produced the minimum noise figure was between about 9 and 10 dB.
Author
FREQUENCY RANGES; INTEGRATED CIRCUITS; NOISE GENERATORS; MICROWAVE CIRCUITS; LOW NOISE; NOISE INTENSITY; WAVEGUIDES
20090035893 NASA Johnson Space Center, Houston, TX, United States
Improved Method of Design for Folding Inflatable Shells
Johnson, Christopher J.; NASA Tech Briefs, October 2009; October 2009; pp. 17-1; In English; Original contains color illustrations
Report No.(s): MSC-24149-1; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035893
http://www.techbriefs.com/component/content/article/5771
An improved method of designing complexly shaped inflatable shells to be assembled from gores was conceived for original application to the inflatable outer shell of a developmental habitable spacecraft module having a cylindrical mid-length section with toroidal end caps. The method is also applicable to inflatable shells of various shapes for terrestrial use. The method addresses problems associated with the assembly, folding, transport, and deployment of inflatable shells that may comprise multiple layers and have complex shapes that can include such doubly curved surfaces as toroids and spheres. One particularly difficult problem is that of mathematically defining fold lines on a gore pattern in a double- curvature region. Moreover, because the fold lines in a double-curvature region tend to be curved, there is a practical problem of how to implement the folds. Another problem is that of modifying the basic gore shapes and sizes for the various layers so that when they are folded as part of the integral structure, they do not mechanically interfere with each other at the fold lines. Heretofore, it has been a common practice to design an inflatable shell to be assembled in the deployed configuration, without regard for the need to fold it into compact form. Typically, the result has been that folding has been a difficult, time-consuming process resulting in a An improved method of designing complexly shaped inflatable shells to be assembled from gores was conceived for original application to the inflatable outer shell of a developmental habitable spacecraft module having a cylindrical mid-length section with toroidal end caps. The method is also applicable to inflatable shells of various shapes for terrestrial use. The method addresses problems associated with the assembly, folding, transport, and deployment of inflatable shells that may comprise multiple layers and have complex shapes that can include such doubly curved surfaces as toroids and spheres. One particularly difficult problem is that of mathematically defining fold lines on a gore pattern in a double- curvature region. Moreover, because the fold lines in a double-curvature region tend to be curved, there is a practical problem of how to implement the folds. Another problem is that of modifying the basic gore shapes and sizes for the various layers so that when they are folded as part of the integral structure, they do not mechanically interfere with each other at the fold lines. Heretofore, it has been a common practice to design an inflatable shell to be assembled in the deployed configuration, without regard for the need to fold it into compact form. Typically, the result has been that folding has been a difficult, time-consuming process resulting in a
Author
CYLINDRICAL BODIES; FOLDING; SPACECRAFT MODULES; DEPLOYMENT; SHAPES; INFLATABLE STRUCTURES; SHELLS (STRUCTURAL FORMS)
20090035894 QorTek, Inc., Williamsport, PA, United States
Pixelized Device Control Actuators for Large Adaptive Optics
Knowles, Gareth J.; Bird, Ross W.; Shea, Brian; Chen, Peter; NASA Tech Briefs, October 2009; October 2009; pp. 6-; In English
Report No.(s): GSC-15666-1; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035894
http://www.techbriefs.com/component/content/article/5759
A fully integrated, compact, adaptive space optic mirror assembly has been developed, incorporating new advances in ultralight, high-performance composite mirrors. The composite mirrors use Q-switch matrix architecture-based pixelized control (PMN-PT) actuators, which achieve high-performance, large adaptive optic capability, while reducing the weight of present adaptive optic systems. The self-contained, fully assembled, 11x11x4-in. (approx.= 28x28x10-cm) unit integrates a very-high-performance 8-in. (approx.=20-cm) optic, and has 8-kHz true bandwidth. The assembled unit weighs less than 15 pounds (=6.8 kg), including all mechanical assemblies, power electronics, control electronics, drive electronics, face sheet, wiring, and cabling. It requires just three wires to be attached (power, ground, and signal) for full-function systems integration, and uses a steel-frame and epoxied electronics. The three main innovations are: 1. Ultralightweight composite optics: A new replication method for fabrication of very thin composite 20-cm-diameter laminate face sheets with good as-fabricated optical figure was developed. The approach is a new mandrel resin surface deposition onto previously fabricated thin composite laminates. 2. Matrix (regenerative) power topology: Waveform correction can be achieved across an entire face sheet at 6 kHz, even for large actuator counts. In practice, it was found to be better to develop a quadrant drive, that is, four quadrants of 169 actuators behind the face sheet. Each quadrant has a single, small, regenerative power supply driving all 169 actuators at 8 kHz in effective parallel. 3. Q-switch drive architecture: The Q-switch innovation is at the heart of the matrix architecture, and allows for a very fast current draw into a desired actuator element in 120 counts of a MHz clock without any actuator coupling.
Author
ACTUATORS; ADAPTIVE OPTICS; ELECTRONIC CONTROL; PIXELS; Q SWITCHED LASERS; SYSTEMS INTEGRATION; WAVEFORMS; BANDWIDTH
20090035895 NASA Goddard Space Flight Center, Greenbelt, MD, United States
T-Slide Linear Actuators
Vranish, John; NASA Tech Briefs, October 2009; October 2009; pp. ; In English; Original contains color illustrations
Report No.(s): GSC-15023-1; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035895
http://www.techbriefs.com/component/content/article/5757
T-slide linear actuators use gear bearing differential epicyclical transmissions (GBDETs) to directly drive a linear rack, which, in turn, performs the actuation. Conventional systems use a rotary power source in conjunction with a nut and screw to provide linear motion. Non-back-drive properties of GBDETs make the new actuator more direct and simpler. Versions of this approach will serve as a long-stroke, ultra-precision, position actuator for NASA science instruments, and as a rugged, linear actuator for NASA deployment duties. The T slide can operate effectively in the presence of side forces and torques. Versions of the actuator can perform ultra-precision positioning. A basic T-slide actuator is a long-stroke, rack-and-pinion linear actuator that, typically, consists of a T-slide, several idlers, a transmission to drive the slide (powered by an electric motor) and a housing that holds the entire assembly. The actuator is driven by gear action on its top surface, and is guided and constrained by gear-bearing idlers on its other two parallel surfaces. The geometry, implemented with gear-bearing technology, is particularly effective. An electronic motor operating through a GBDET can directly drive the T slide against large loads, as a rack and pinion linear actuator, with no break and no danger of back driving. The actuator drives the slide into position and stops. The slide holes position with power off and no brake, regardless of load. With the T slide configuration, this GBDET has an entire T-gear surface on which to operate. The GB idlers coupling the other two T slide parallel surfaces to their housing counterpart surfaces provide constraints in five degrees-of-freedom and rolling friction in the direction of actuation. Multiple GB idlers provide roller bearing strength sufficient to support efficient, rolling friction movement, even in the presence of large, resisting forces. T-slide actuators can be controlled using the combination of an off-the-shelf, electric servomotor, a motor angle resolution sensor (typically an encoder or resolver), and microprocessor-based intelligent software. In applications requiring precision positioning, it may be necessary to add strain gauges to the T-slide housing. Existing sensory- interactive motion control art will work for T slides. For open-loop positioning, a stepping motor emulation technique can be used.
Author
ACTUATORS; BEARINGS; GEARS; TORQUE; STEPPING MOTORS; ROLLER BEARINGS; MICROPROCESSORS; INTERACTIVE CONTROL; FRICTION; DEPLOYMENT
20090035896 California Inst. of Tech., Pasadena, CA, United States
LDPC Codes with Minimum Distance Proportional to Block Size
Divsalar, Dariush; Jones, Christopher; Dolinar, Samuel; Thorpe, Jeremy; NASA Tech Briefs, October 2009; October 2009; pp. 30-3; In English; Original contains color illustrations
Report No.(s): NPO-42063; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035896
http://www.techbriefs.com/component/content/article/5792
Low-density parity-check (LDPC) codes characterized by minimum Hamming distances proportional to block sizes have been demonstrated. Like the codes mentioned in the immediately preceding article, the present codes are error-correcting codes suitable for use in a variety of wireless data-communication systems that include noisy channels. The previously mentioned codes have low decoding thresholds and reasonably low error floors. However, the minimum Hamming distances of those codes do not grow linearly with code-block sizes. Codes that have this minimum-distance property exhibit very low error floors. Examples of such codes include regular LDPC codes with variable degrees of at least 3. Unfortunately, the decoding thresholds of regular LDPC codes are high. Hence, there is a need for LDPC codes characterized by both low decoding thresholds and, in order to obtain acceptably low error floors, minimum Hamming distances that are proportional to code-block sizes. The present codes were developed to satisfy this need. The minimum Hamming distances of the present codes have been shown, through consideration of ensemble-average weight enumerators, to be proportional to code block sizes. As in the cases of irregular ensembles, the properties of these codes are sensitive to the proportion of degree-2 variable nodes. A code having too few such nodes tends to have an iterative decoding threshold that is far from the capacity threshold. A code having too many such nodes tends not to exhibit a minimum distance that is proportional to block size. Results of computational simulations have shown that the decoding thresholds of codes of the present type are lower than those of regular LDPC codes. Included in the simulations were a few examples from a family of codes characterized by rates ranging from low to high and by thresholds that adhere closely to their respective channel capacity thresholds; the simulation results from these examples showed that the codes in question have low error floors as well as low decoding thresholds. As an example, the illustration shows the protograph (which represents the blueprint for overall construction) of one proposed code family for code rates greater than or equal to 1.2. Any size LDPC code can be obtained by copying the protograph structure N times, then permuting the edges. The illustration also provides Field Programmable Gate Array (FPGA) hardware performance simulations for this code family. In addition, the illustration provides minimum signal-to-noise ratios (Eb/No) in decibels (decoding thresholds) to achieve zero error rates as the code block size goes to infinity for various code rates. In comparison with the codes mentioned in the preceding article, these codes have slightly higher decoding thresholds.
Author
DATA TRANSMISSION; TELECOMMUNICATION; CHANNEL CAPACITY; ERROR CORRECTING CODES; DECODING
20090035897 Alliant Techsystems, Inc., United States
Two-Piece Screens for Decontaminating Granular Material
Backes, Douglas; Poulter, Clay; Godfrey, Max; Dutton, Melinda; Tolman, Dennis; NASA Tech Briefs, October 2009; October 2009; pp. 1; In English
Report No.(s): MFS-32496-1; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035897
http://www.techbriefs.com/component/content/article/5776
Two-piece screens have been designed specifically for use in filtering a granular material to remove contaminant particles that are significantly wider or longer than are the desired granules. In the original application for which the twopiece screens were conceived, the granular material is ammonium perchlorate and the contaminant particles tend to be wires and other relatively long, rigid strands. The basic design of the twopiece screens can be adapted to other granular materials and contaminants by modifying critical dimensions to accommodate different grain and contaminant- particle sizes. A two-piece screen of this type consists mainly of (1) a top flat plate perforated with circular holes arranged in a hexagonal pattern and (2) a bottom plate that is also perforated with circular holes (but not in a pure hexagonal pattern) and is folded into an accordion structure. Fabrication of the bottom plate begins with drilling circular holes into a flat plate in a hexagonal pattern that is interrupted, at regular intervals, by parallel gaps. The plate is then folded into the accordion structure along the gaps. Because the folds are along the gaps, there are no holes at the peaks and valleys of the accordion screen. The top flat plate and the bottom accordion plate are secured within a metal frame. The resulting two-piece screen is placed at the bottom opening of a feed hopper containing the granular material to be filtered. Tests have shown that such long, rigid contaminant strands as wires readily can pass through a filter consisting of the flat screen alone and that the addition of the accordion screen below the flat screen greatly increases the effectiveness of removal of wires and other contaminant strands. Part of the reason for increased effectiveness is in the presentation of the contaminant to the filter surface. Testing has shown that wire type contamination will readily align itself parallel to the material direction flow. Since this direction of flow is nearly always perpendicular to the filter surface holes, the contamination is automatically aligned to pass through. The two-filter configuration reduces the likelihood that a given contaminant strand will be aligned with the flow of material by eliminating the perpendicular presentation angle. Thus, for wires of a certain diameter, a two-piece screen is 20 percent more effective than is the corresponding flat perforated plate alone, even if the holes in the flat plate are narrower. An accordion screen alone is similarly effective in catching contaminants, but lumps of agglomerated granules of the desired material often collect in the valleys and clog the screen. The addition of a flat screen above the accordion screen prevents clogging of the accordion screen. Flat wire screens have often been used to remove contaminants from granular materials, and are about as effective as are the corresponding perforated flat plates used alone.
Author
GRANULAR MATERIALS; DECONTAMINATION; PERFORATED PLATES; FRAMES; AMMONIUM PERCHLORATES
20090035898 Jet Propulsion Lab., California Inst. of Tech., Pasadena, CA, United States
Instruments for Imaging from Far to Near
Mungas, Greg; Boynton, John; Sepulveda, Cesar; NASA Tech Briefs, October 2009; October 2009; Original contains color illustrations
Report No.(s): NPO-44780; Copyright; Avail.: CASI, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035898
http://www.techbriefs.com/component/content/article/5797
The acronym CHAMP (signifying camera, hand lens, and microscope ) denotes any of several proposed optoelectronic instruments that would be capable of color imaging at working distances that could be varied continuously through a range from infinity down to several millimeters. As in any optical instrument, the magnification, depth of field, and spatial resolution would vary with the working distance. For example, in one CHAMP version, at a working distance of 2.5 m, the instrument would function as an electronic camera with a magnification of 1/100, whereas at a working distance of 7 mm, the instrument would function as a microscope/electronic camera with a magnification of 4.4. Moreover, as described below, when operating at or near the shortest-working-distance/highest-magnification combination, a CHAMP could be made to perform one or more spectral imaging functions. CHAMPs were originally intended to be used in robotic geological exploration of the Moon and Mars. The CHAMP concept also has potential for diverse terrestrial applications that could include remotely controlled or robotic geological exploration, prospecting, field microbiology, environmental surveying, and assembly- line inspection. A CHAMP (see figure) would include two lens cells: (1) a distal cell corresponding to the objective lens assembly of a conventional telescope or microscope and (2) a proximal cell that would contain the focusing camera lens assembly and the camera electronic image-detector chip, which would be of the active-pixel-sensor (APS) type. The distal lens cell would face outward from a housing, while the proximal lens cell would lie in a clean environment inside the housing. The proximal lens cell would contain a beam splitter that would enable simultaneous use of the imaging optics (that is, proximal and distal lens assemblies) for imaging and illumination of the field of view. The APS chip would be mounted on a focal plane on a side face of the beam splitter, while light for illuminating the field of view would enter the imaging optics via the end face of the beam splitter. The proximal lens cell would be mounted on a sled that could be translated along the optical axis for focus adjustment. The position of the CHAMP would initially be chosen at the desired working distance of the distal lens from (corresponding to an approximate desired magnification of) an object to be examined. During subsequent operation, the working distance would ordinarily remain fixed at the chosen value and the position of the proximal lens cell within the instrument would be adjusted for focus as needed.
Author
IMAGING TECHNIQUES; SPATIAL RESOLUTION; OPTICAL THICKNESS; TELESCOPES; FIELD OF VIEW; LENSES; MAGNIFICATION
20090035899 California Inst. of Tech., Pasadena, CA, United States
Three MMIC Amplifiers for the 120-to-200 GHz Frequency Band
Samoska, Lorene; Schmitz, Adele; NASA Tech Briefs, October 2009; October 2009; pp. 13-1; In English; Original contains color illustrations
Report No.(s): NPO-42846; Copyright; Avail.: CASI: A01, Hardcopy
Avail Online: http://hdl.handle.net/2060/20090035899
http://www.techbriefs.com/component/content/article/5761
Closely following the development reported in the immediately preceding article, three new monolithic microwave integrated circuit (MMIC) amplifiers that would operate in the 120-to-200-GHz frequency band have been designed and are under construction at this writing. The active devices in these amplifiers are InP high-electron-mobility transistors (HEMTs). These amplifiers (see figure) are denoted the LSLNA150, the LSA200, and the LSA185, respectively. Like the amplifiers reported in the immediately preceding article, the LSLNA150 (1) is intended to be a prototype of low-noise amplifiers (LNAs) to be incorporated into spaceborne instruments for sensing cosmic microwave background radiation and (2) has potential for terrestrial use in electronic test equipment, passive millimeter-wave imaging systems, radar receivers, communication receivers, and systems for detecting hidden weapons. The HEMTs in this amplifier were fabricated according to 0.08- m design rules of a commercial product line of InP HEMT MMICs at HRL Laboratories, LLC, with a gate geometry of 2 fingers, each 15 m wide. On the basis of computational simulations, this amplifier is designed to afford at least 15 dB of gain, with a noise figure of no more than about 6 dB, at frequencies from 120 to 160 GHz. The measured results of the amplifier are shown next to the chip photo, with a gain of 16 dB at 150 GHz. Noise figure work is ongoing. The LSA200 and the LSA185 are intended to be prototypes of transmitting power amplifiers for use at frequencies between about 180 and about 200 GHz. These amplifiers have also been fabricated according to rules of the aforesaid commercial product line of InP HEMT MMICs, except that the HEMTs in these amplifiers are characterized by a gate geometry of 4 fingers, each 37 m wide. The measured peak performance of the LSA200 is characterized by a gain of about 1.4 dB at a frequency of 190 GHz; the measured peak performance of the LSA185 is characterized by a gain of about 2.7 dB at a frequency of 181 GHz. The measured gain results of each chip are shown next to their respective photos.
Author
HIGH ELECTRON MOBILITY TRANSISTORS; MICROWAVE CIRCUITS; INTEGRATED CIRCUITS; COSMIC MICROWAVE BACKGROUND RADIATION; MILLIMETER WAVES; ELECTRONIC EQUIPMENT
20090035900 California Inst. of Tech., Pasadena, CA, United States
Constructing LDPC Codes from Loop-Free Encoding Modules
Divsalar, Dariush; Dolinar, Samuel; Jones, Christopher; Thorpe, Jeremy; Andrews, Kenneth; NASA Tech Briefs, October 2009; October 2 | |
