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OMI/Aura Level 1B VIS Zoom-in Geolocated Earthshine Radiances 1-orbit L2 Swath 13x12 km V003
nasa-test-0.demo.socrata.com | Last Updated 2015-07-20T04:54:21.000ZThe Level-1B (L1B) Radiance Product OML1BRVZ (Version-3) from the Aura-OMI is now available (http://disc.gsfc.nasa.gov/Aura/OMI/oml1brvz_v003.shtml) to public from the NASA GSFC Earth Sciences Data and Information Services Center (GES DISC). OMI calibrated and geolocated radiances for the channels in the UV1 (264-311 nm), UV2 (307-383 nm)and VIS(349-504) regions, spectral irradiances, calibration measurements, and all derived geophysical atmospheric products are archived at the NASA Goddard DAAC. (The shortname for this OMI Level-1B Product is OML1BRVZ) The lead algorithm scientist for this product is Dr. Marcel Dobber from the KNMI. The OMI Level 1B Visible Radiance Zoom-in Product OML1BRVZ contains geolocated Earth view spectral radiances from the VIS channel detectors in the wavelength range of 349 to 504 nm. The product contains the measurements that are taken once a month using the spatial zoom-in measurement modes (30 pixels covering 750 km swath width). In spatial zoom in mode the nadir ground pixel size is 13 x 12 km2 and measurements are available only for the wavelengths 306 to 432 nm. OML1BRVZ files are stored in EOS Hierarchical Data Format (HDF-EOS 2.4) which is based on HDF4. The radiance for the earth measurements (also referred as signal) and its precision are stored as a 16 bit mantissa and an 8-bit exponent. The signal can be computed using the equation: signal = signal_mantissa x 10 exponent . For the precision, the same exponent is used as for the signal. Each file contains data from the day lit portion of an orbit (~53 minutes) and is roughly 570 MB in size. There are approximately 14 orbits per day.
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Planning for Planetary Science Mission Including Resource Prospecting Project
nasa-test-0.demo.socrata.com | Last Updated 2015-07-20T05:33:43.000ZAdvances in computer-aided mission planning can enhance mission operations and science return for surface missions to Mars, the Moon, and beyond. While the innovations envisioned by this program are broadly applicable, they serve an immediate and urgent need for missions to prospect for volatiles at the lunar poles (i.e., the NASA Lunar Resource Prospector Mission, currently in Phase A). These missions must be rapid and precise, covering multiple kilometers in approximately 10-12 Earth days to complete mission objectives in one lunar light cycle. This calls for the ability to drive intentionally and efficiently to precise drilling destinations. Polar operations encounter low angle lighting; this creates shadows which confront robot operations with challenges in power production, thermal control, and operator situational awareness. This demands robust path planning for efficient mission planning and execution. The proposed work develops a computer-aided mission planning tool that balances the competing demands of efficient routes, scientific information gain, and rover constraints (e.g., kinematics, communication, power, thermal, and terrainability) to generate and analyze optimized routes between sequences of locations. Planner-computed statistics about the set of viable paths enable mission planners, scientists, and operators to efficiently select routes considering a range of priorities including risk, duration, and science return. This planner will serve an invaluable role in preplanning missions and as a tool for rapidly understanding the impact of changes in mission profile during the mission execution.
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Including the effects of a harsh radiation environment in the simulation and design of nanoelectronic devices and circuits Project
nasa-test-0.demo.socrata.com | Last Updated 2015-07-20T05:31:59.000ZNanoelectronic devices, and circuits based on such devices, are expected to be more susceptible to the effects of radiation than the previous generation of devices and circuits. Circuits that can operate in harsh radiation environments are essential components of commercial satellite communications systems, space exploration vehicles, and national defense systems. Hence there is a critical need to understand and quantify the effects of radiation on the present and next generation of nanoelectronic circuits, and to develop methods to render such circuits insensitive to radiation. In this project we intend to identify and characterize (as a function of device dimension if possible) the deleterious effects of radiation on nanoscale devices. More importantly, we intend to build on the standard models, which describe the effects of radiation, and develop software that would enable the modeling and simulation of radiation effects. First we will consider conventional nanoelectronic devices --- that is those where charge transport is based on the usual principles of drift and diffusion. Then a tool for the effects of radiation on single electron transistors and amplifiers (including those based on carbon nanotubes) would also be developed. Using the software, methods to mitigate the effects of radiation by rad-hard designs will be examined.
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Wide Temperature Range DC-DC Boost Converters for Command/Control/Drive Electronics Project
nasa-test-0.demo.socrata.com | Last Updated 2015-07-20T05:23:03.000ZWe shall develop wide temperature range DC-DC boost converters that can be fabricated using commercial CMOS foundries. The boost converters will increase the low voltage supply (~ 0.7 to 3V) of an advanced CMOS integrated circuit to the higher values (3-10V) required for integrated command/control/drive electronics for sensors, actuators and instrumentation. The high voltage capability is a result of our patented, CMOS compatible transistor technology that is radiation tolerant (TID>1 MRad), SEL immune and capable of wide temperature range operation (-196C to +150C). This new transistor technology has been demonstrated at multiple foundries and advanced device models are available for circuit design and simulation. The DC-DC boost converters will be integrated directly with the CMOS components to provide a single chip solution, greatly reducing the number of active and passive components that would otherwise be required. By allowing enhanced voltage operation in future CMOS technology nodes we will be avoiding many of the obsolescence problems facing NASA missions that are dependent upon commercial electronics. The circuits will be designed to operate in low temperature environments that experience wide temperature swings such as those found on the moon, Mars, Titan, Europa and comets.
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Modular, Fault-Tolerant Electronics Supporting Space Exploration Project
nasa-test-0.demo.socrata.com | Last Updated 2015-07-20T05:26:45.000ZModern electronic systems tolerate only as many point failures as there are redundant system copies, using mere macro-scale redundancy. Fault Tolerant Electronics Supporting Space Exploration (FTESSE) creates an electronic design paradigm using reprogrammable FPGAs to create swappable Circuit Object Blocks (COBs) ? analogous to software objects ? for the first time enabling redundancy on a micro-scale. The result is an increased tolerance of point failures by several orders of magnitude over traditional approaches. In the FTESSE approach, FPGAs are partitioned into COBs (groups of gates), each performing a specific function. Bad areas can be mapped like the bad sector data on a disk drive, enabling COBs to be placed in areas of working gates to recover system performance. Hardware tested during Phase I verified point failures could be introduced into an example circuit and corrected. As in the Phase I model, circuits to be monitored reside on a Slave FPGA, and a Master FPGA monitors outputs of all COBs, sensing faults and mapping non-working gates on the Slave FPGA. The Master is a rad-hard, triple mode redundancy (TMR) FPGA, but the Slaves need not be, opening the doors to higher performance applications while maintaining high levels of fault tolerance.
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Electronics Modeling and Design for Cryogenic and Radiation Hard Applications Project
nasa-test-0.demo.socrata.com | Last Updated 2015-07-20T05:16:28.000ZWe are developing CAD tools, models and methodologies for electronics design for circuit operation in extreme environments with a focus on very low temperature and radiation effects. These new tools will help enable NASA to design next generation electronics especially for planetary projects including the Europa Jupiter System Mission. The new models and tools will be directly incorporated into industry standard CAD products to ensure their usability and extend their applicability to extreme environments. Such capabilities will significantly improve reliability, performance and lifetime of electronics that are used for space missions. This will be achieved through the development of novel compact and distributed device modeling capabilities for radiation-hard and extreme temperature instrument design, as well as techniques for circuit design that help to predict the vulnerability of circuits to degradation and upset from radiation. Research and development is indicating that standard bulk silicon CMOS and SOI processes operate well under these extreme conditions so that there is little need for NASA to commit to large expenditures for exotic materials. Models and CAD tools are relatively inexpensive as compared to fabrication costs; thus the results of this project should provide a very large return on investment.
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Pyramid Comet Sampler Project
nasa-test-0.demo.socrata.com | Last Updated 2015-07-20T05:34:48.000ZBased on the sampling requirements, we propose an Inverted Pyramid sampling system. Each face of the pyramid includes a cutting blade which is independently actuated by redundant pyrotechnic actuators. Such sampler shape has a number of advantages. The pyramidal V shape acts as an arrow piercing into the comet surface at a steep angle. The 4 opposing blades offset tangential forces, meaning that only vertical forces would need to be reacted during impact. These forces could be minimized by making the pyramid height low (and in turn the pyramid would be more flat). In the latest Decadal Survey, the committee recommended selecting a Comet Surface Sample Return mission as one of the five New Frontiers 4 (NF4) missions, solidifying the importance of studying returned physical samples from a comet. Lunar South Pole-Aitken Basin Sample Return could also benefit from the development of this sampling approach.
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Extreme Temperature, Rad-Hard Power Management ASIC Project
nasa-test-0.demo.socrata.com | Last Updated 2015-07-20T05:14:50.000ZRidgetop Group will design a rad-hard Application Specific Integrated Circuit (ASIC) for spacecraft power management that is functional over a temperature range of -230 to +130 <SUP>o</SUP>C. This ASIC is intended to work in conjunction with a Fuel Cell power system and battery back-up to provide uninterrupted power to critical modules in Space. Ridgetop will combine Radiation Hardening (RH) techniques with Large Scale Integration (LSI) methodologies to build a power management system for spacecraft applications onto a single monolithic circuit. The significance of this innovation is a single reliable component (ASIC) that will meet platform requirements for high voltage, wide operating temperature range, and radiation tolerance (minimum 100 krads Total Ionizing Doze (TID), 100 MeVcm2/mg Single Event Latchup (SEL). During phase 1, we will select two functional blocks from within a representative NASA power management system as test cases. Designs for these blocks will be developed and validated through SPICE circuit and radiation simulations, using technology files provided by a commercial foundry. In phase 2, Ridgetop will deliver working prototype integrated circuits (ICs) that meet and exceed the above requirements.
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TRMM Precipitation Radar (PR) Level 2 Rainfall Rate and Profile Product (TRMM Product 2A25) V7
nasa-test-0.demo.socrata.com | Last Updated 2015-07-19T08:53:20.000ZThe TRMM Precipitation Radar (PR), the first of its kind in space, is an electronically scanning radar, operating at 13.8 GHz that measures the 3-D rainfall distribution over both land and ocean, and defines the layer depth of the precipitation. The objectives of 2A25 is to correct for the rain attenuation in measured radar reflectivity and to estimate the instantaneous three-dimensional distribution of rain from the TRMM Precipitation Radar (PR) data. The estimates of attenuation-corrected radar reflectivity factor and rainfall rate are given at each resolution cell of the PR. The estimated near-surface rainfall rate and average rainfall rate between the two pre-defined altitudes (2 and 4 km) are also calculated for each beam position. 2A25 basically uses a hybrid of the Hitschfeld-Bordan method and the surface reference method to estimate the vertical true radar reflectivity (Z) profile. (The hybrid method is described in Iguchi and Meneghini (1994)). The vertical rain profile is then calculated from the estimated true Z profile by using an appropriate Z-R relationship. The attenuation correction is, in principle, based on the surface reference method. This method assumes that the decrease in the apparent surface cross section (delta sigma-zero) is caused by the propagation loss in rain. The coefficient a in the k-Z relationship, k=a Z**b, is adjusted in such a way that the path-integrated attenuation (PIA) estimated from the measured Zm-profile will match the delta sigma-zero. The attenuation correction of Z is carried out by the Hitschfeld-Bordan method with the modified a. Since a is adjusted, this type of surface reference method is called the a-adjustment method. The a-adjustment method assumes that the discrepancy between the PIA estimate from delta sigma-zero and that from the measured Zm-profile can be attributed to the inappropriate choice of a values, which may vary depending on the raindrop size distribution and other conditions. It assumes that the radar is properly calibrated and that the measured Zm has no error. In order to avoid inaccuracies in the attenuation correction when rain is weak, a hybrid of the surface reference method and the Hitschfeld-Bordan method is used (Iguchi and Meneghini, 1994). The PIA is first estimated from the precipitation echo alone. The weight given by the hybrid method to the PIA estimate from the surface reference increases as the attenuation estimate increases. When rain is very weak and the attenuation estimate is small, the PIA estimate from the surface reference is effectively neglected. With the introduction of the hybrid method, the divergence associated with the Hitschfeld-Bordan method is also prevented. One major difference from the method described in the above reference is that, in order to deal with the beam-filling problem, a non-uniformity parameter is introduced and is used to correct the bias in the surface reference arising from the horizontal non-uniformity of rain field within the beam. Since radar echoes from near the surface are contaminated by the mainlobe clutter, the rain estimate at the lowest point in the clutter-free region is given as the near-surface rainfall rate for each angle bin. Spatial coverage is between 38 degrees North and 38 degrees South, owing to the 35 degree inclination of the TRMM satellite. This orbit provides extensive coverage in the tropics and allows each location to be covered at a different local time each day, enabling the analysis of the diurnal cycle of precipitation. There are, in general, 9150 scans along the orbit, with each scan consisting of 49 rays. The scan width is about 220 km. The data are stored in the Hierarchical Data Format (HDF), which includes both core and product specific metadata applicable to the PR measurements. A fi...
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Gridded Population of the World, Version 2 (GPWv2)
nasa-test-0.demo.socrata.com | Last Updated 2015-07-19T08:03:40.000ZGridded Population of the World, Version 2 (GPWv2) consists of estimates of human population for the years 1995 and 1990 by 2.5 arc-minute grid cells. The data products are population counts (raw counts), population densities (per square km), and land area (actual area net of ice and water), all of which are available in two GIS-compatible data formats at the global, continent (Antarctica not included), and country levels. A proportional allocation gridding algorithm, utilizing 127,105 national and sub-national administrative units, is used to assign population values to grid cells. Advantages to GPWv2 include higher quality data from the U.S., Africa, Australia, Canada, Europe, Russia, New Zealand, and India; 8 times the number of administrative units; national population estimates that have been adjusted to match the United Nations national estimated population for each country; a proportional allocation algorithm that reduces error with multiple input polygons; and higher spatial resolution. GPWv2 is produced by the Columbia University Center for International Earth Science Information Network (CIESIN) in collaboration with the International Food Policy Research Institute (IFPRI) and the World Resources Institute (WRI). (Suggested Usage: To serve a wide user community by providing the latest data on human population distribution that can be used in interdisciplinary studies of the environment.)