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- API nasa-test-0.demo.socrata.com | Last Updated 2015-07-19T08:14:31.000Z
This data set contains proportional estimates for the vegetative cover types of tree cover, herbaceous vegetation, and bare ground over South America for the period 2000-2001. These products were derived from all seven bands of the Moderate-resolution Imaging Spectroradiometer (MODIS) sensor onboard NASA's Terra satellite. A set of 500-m MOD09A1 Surface Reflectance 8-day minimum blue reflectance composites were used as input data. To reduce the presence of cloud shadows, The data were converted to 40-day composites using a second darkest albedo (sum of blue, green, and red bands), and the Vegetation Continuous Fields (VCF) algorithmn was utilized (Hansen et al., 2002). The VCF shows how much of a land cover such as forest or grassland exists anywhere on the land surface. The VCF product may depict areas of heterogeneous land cover better than traditional discrete classification schemes which shows where land cover types are concentrated. There are three images provided in GeoTIFF format.
- API nasa-test-0.demo.socrata.com | Last Updated 2015-07-20T05:08:14.000Z
While continuously increasing in complexity, the payloads of terrestrial high altitude balloons need a thermal management system to reject their waste heat and to maintain a stable temperature as the air (sink) temperature swings from as cold as -90<SUP>o</SUP>C to as hot as +40<SUP>o</SUP>C. Currently, constant conductance, copper-methanol heat pipes are utilized on balloon payloads to remove the waste heat. It would be desirable to use a Variable Conductance Heat Pipe (VCHP) instead, to allow the thermal resistance to increase under cold operating or cold survival environment conditions, keeping the instrument section warm. In spacecraft, thermal management is achieved using axially-grooved aluminum-ammonia heat pipes and VCHPs, which are relatively expensive to manufacture and validate. Advanced Cooling Technologies, Inc. (ACT) is proposing a low-cost VCHP based on smooth-bore, thin-wall stainless steel tubing, with either methanol or pentane as working fluids, that is capable of passively maintaining a relatively constant evaporator (payload) temperature while the sink temperature varies between -90<SUP>o</SUP>C and +40<SUP>o</SUP>C. The thin wall will be much lighter and will provide much better temperature control due to its higher thermal resistance, while the combination of working fluid and envelope material result in a heat pipe that is much less expensive to manufacture than standard grooved aluminum heat pipes. Spacecraft VCHPs normally have the gas reservoir at the end of the condenser, and maintain its temperature with electrical heaters. The proposed VCHP moves the reservoir near the evaporator, eliminating the need for electrical power to control the temperature. Preliminary calculations show that either system, methanol based or pentane based, is capable of meeting the thermal performance requirements. For both the pentane and methanol systems, the evaporator (payload) temperature varies less than 6<SUP>o</SUP>C while the heat sink temperature varies from 90<SUP>o</SUP>C to +40<SUP>o</SUP>C.
- API nasa-test-0.demo.socrata.com | Last Updated 2015-07-19T08:53:14.000Z
The primary objective of algorithm 3A25 is to compute various rainfall statistics over a month from the level 2 PR products. The statistics are derived at two spatial resolutions: (1) a standard space scale of 5 degrees by 5 degrees (latitude x longitude) cells and (2) a high resolution subset of 0.5 degree x 0.5 degree cells. The output variables include rainfall rate (mm/hour) profile at 2, 4, 6, 10, and 15 km, fractional rain, snow ice layer, and surface rain rate (mm/hour). The output statistics include probabilities of occurrence, means and standard deviations, histograms, and correlation coefficients. All statistics in 3A-25, except near-surface rain rate, are computed only when rain is judged in 1C-21 to be "certain." When rain is judged in 1C-21 to be "possible," the observation is treated as a "no-rain" observation. For the near-surface rain rate, the statistics (mean, standard deviation, and histogram) are computed for "rain-possible" as for the usual "rain-certain." Because the "rain-possible" cases are dominated by noise so that the probability of false-alarm is high, the "rain-certain" statistics should be considered as more representative of the TRMM radar data. Three types of rain rates are defined in 3A-25: (1) a "near-surface" rain rate that is obtained from the range bin closest to the surface which is not corrupted by the surface clutter, (2) a path-averaged rain rate calculated by summing the values from the storm top (first gate where rain is detected) to the last gate (gate nearest to the surface uncontaminated by surface clutter) and dividing by the number of gates in the interval, and (3) those at fixed heights above the ellipsoid (2, 4, 6, 10, and 15 km). Spatial coverage is between 40 degrees North and 40 degrees South, owing to the 35 degree inclination of the TRMM satellite. The data are stored in the Hierarchical Data Format (HDF). The low resolution grids are in the Planetary Grid 1 structure, and the high resolution grids are in the Planetary Grid 2 structure. The file size (one file per month) is about 16 MB (uncompressed). The description of file component objects can be obtained from Volume 4 - Levels 2 and 3 File Specifications provided by the TRMM Science Data and Information System (TSDIS): "http://pps.gsfc.nasa.gov/". The Tropical Rainfall Measuring Mission (TRMM) is a joint U.S.-Japan satellite mission to monitor tropical and subtropical precipitation and to estimate its associated latent heating. TRMM was successfully launched on November 27, at 4:27 PM (EST) from the Tanegashima Space Center in Japan. The 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.
- API nasa-test-0.demo.socrata.com | Last Updated 2015-07-19T09:12:27.000Z
This data set contains elevation, roll, pitch, and heading measurements over Antarctica using the Ashtech GG24 GPS+ receiver and the Systron and Donner MMQ-50 Inertial Measurement Unit (IMU). The data were collected by scientists working on the Investigating the Cryospheric Evolution of the Central Antarctic Plate (ICECAP) project, which is funded by the National Science Foundation (NSF) and the Natural Environment Research Council (NERC) with additional support from NASA Operation IceBridge.
- API nasa-test-0.demo.socrata.com | Last Updated 2015-07-19T07:53:36.000Z
Fluxes of carbon dioxide, water vapor, and energy exchange have been measured at 38 forest, grassland, and crop sites as part of the EUROFLUX and AmeriFlux projects. A total of 97 site-years of data were compiled, primarily between 1996 and 1998 but also for 1992-1995 and 1999-2000. Half-hour flux and meteorology measurements are included plus the gap-filled half-hour estimates and aggregations to day and night, weekly, monthly, and annual periods. The FLUXNET 2000 Synthesis Workshop was held at the Marconi Conference Center, Marshall, California, June 11-14, 2000. The Marconi Flux Data Collection was compiled to aid in exploring the interactions between the terrestrial biosphere and the overlying atmosphere through carbon, water, and energy exchanges. The workshop resulted in several studies to synthesize and interpret differences and similarities in long-term measurements of carbon dioxide, water vapor, and energy exchanges between vegetation and the atmosphere for a spectrum of ecosystems. A series of synthesis papers based on these data and studies was published in a special issue of the Agriculture and Forest Meteorology, Volume 113, 2002. The papers are listed in the reference section. This data product is being archived as a record of the data used the AFM special issue. Updates and revisions to the data are available at the FLUXNET web site.The eddy covariance technique is used for long-term continuous measurements of mass and energy fluxes to capture seasonal dynamics and allow for a meaningful scaling with respect to time. The equipment and methodology were standardized among sites by using common software and instrumentation. Comparisons of ecosystem fluxes among sites are usually performed on annual or monthly sums calculated on complete data records; however, the average site data coverage during a year was only 65%. Therefore, development and application of robust and consistent data gap-filling methods was required before fluxes could be calculated. One of the outcomes of the FLUXNET project was computer applications to process the data into complete, consistent, quality assured, and documented data sets (Falge et al. 2001a,b). Gap-filled flux data from four different filling methods are reported. Selected meteorological parameters were also gap filled to support flux estimating methods and are reported along with non-filled meteorological data. Note that the measured/estimated CO2 fluxes and storage fluxes were summed into net ecosystem exchange (NEE), and ONLY NEE data are reported.
- API nasa-test-0.demo.socrata.com | Last Updated 2015-07-20T05:32:41.000Z
With its constantly evolving portfolio of highly technical systems requiring human construction maintenance and operation, NASA has an extreme form of a common yet challenging training problem: how to ensure that personnel are qualified on the (often changing) procedures required to work on or with these systems. Simulation-based training that enables learning while doing is a proven approach, but dependence on hardware-based simulators and the requirement for human instructors to develop and supervise training scenarios raise costs and limit flexibility in delivering training and retraining. We propose to build a distributable intelligent tutoring system (ITS) exploiting a unified representation of human and robotic mission activities that can be used to (1) trace student activity to assess, prompt, and correct their actions, (2) simulate robotic activity, (3) control training scenario generation/selection, (4) cover both general and specific cases, (5) allow for varying degrees of detail in human and robotic activity, (6) support extended scenarios involving multiple procedures, and (7) track detailed re-training requirements resulting from changes in procedures. The innovative merger of general procedure descriptions with specific scenario scripts will facilitate more efficient authoring of consistent broad-coverage automated simulation-based training while retaining the ability to author specific scenarios when needed.
- API nasa-test-0.demo.socrata.com | Last Updated 2015-07-20T05:21:31.000Z
Electrical checkout and testing is a critical part of the overall spacecraft integration and test flow. Verifying proper harness and connector signal interfaces is key to ensuring component health and overall system functionality. Break-Out Boxes (BOB) are used to give test personnel access to electrical signals for probing, voltage injection, isolation checks, safe-to-mate checks, and voltage/current measurements. Currently this involves manually attaching multimeters and oscilloscopes to banana jacks on the BOB, taking measurements and comparing to expected results. Tiger Innovations proposes designing an automated break-out box to make electrical integration activities more efficient, repeatable, and safe by introducing software controlled test sequences and reducing human errors. Additionally, significant schedule and cost reductions are realized by improving the speed and reliability of integration operations. Our software controlled BOB would allow isolation and safe-to-mate checks to be accomplished in a fraction of the time required for a human operator. Voltage and current measurements would be analyzed in the software for pass/fail criteria and reported to the user for inclusion in the test log. Automating test sequences through the use of an automated BOB has the potential to significantly streamline spacecraft, payload and launch site electrical integration and test activities.
A Compact Immersion Grating Spectrometer with Quantum Capacitance Detectors for Space-Borne Far-IR Spectroscopy Projectnasa-test-0.demo.socrata.com | Last Updated 2015-07-20T05:35:49.000Z
<p>SPECTROMETER:&nbsp; The grating spectrometer uses a curved grating fabricated on a high resistivity silicon wafer. Light will be coupled in via a silicon immersion lens and coupling waveguide. The wafer profile, including the grating facets are defined by photolithography and deep reactive etching (DRIE) and the wafer is metallized on both sides for better light confinement (except in the regions below where the detector antennas will be placed).&nbsp; The grating both focuses and diffracts the light in the plane of the wafer to a focal arc, where the detectors are positioned. QCD DETECTOR ARRAY: The Quantum Capacitance Detector is a mesoscopic superconducting device that exploits its extreme susceptibility to the presence of quasiparticle excitations arising from pair-breaking radiation to enable background limited detection.&nbsp; QCDs have demonstrated photon noise limited performance&nbsp; at 1.5THz for optical loadings 10-20 to 10-17W.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; The detector die will be placed directly on top of the spectrometer wafer and will have an array of QCDs with antennas positioned at the focusing spots of each wavelength.&nbsp; Each detector will be coupled to a superconducting resonator with a different resonant frequency to allow for frequency multiplexing with a single feedline coupling the RF signal to all resonators.&nbsp; A&nbsp; prototype with 32 spectral channels will be demonstrated</p>
- API nasa-test-0.demo.socrata.com | Last Updated 2015-07-20T05:09:05.000Z
This data set includes monthly grassland biomass data, net primary productivity (NPP) estimates, and climate (rainfall amounts and temperature) data for multiple study sites in major grassland types worldwide. Field measurements of biomass and associated environmental data were compiled for the multiple grassland study sites. When sufficient biomass data were available, NPP was estimated by six different algorithms for 31 grassland sites to examine potential bias associated with the algorithms (Scurlock et al. 2002).The data consisted of monthly measurements of biomass components including aboveground live material, standing dead, litter, belowground biomass, and belowground dead material. However, many of the sites did not collect all of the components. There are 1,477 field measurements of some component of NPP, all sites having at least aboveground biomass measurements. Of the 31 sites, 20 also measured standing dead and litter or total live plus dead material. In addition, 17 sites measured total belowground biomass, and six of these sites provided separate measurements of live and dead root components. The study sites had from 1 to 29 years of biomass data with an average of three years per site. Five ecoregions were represented, including cold desert steppe, temperate dry steppe, humid savanna, humid temperate, and savanna. The selection of study sites was based on the availability of complete and consistent information on NPP or at least partial NPP, together with the dynamics of live biomass and dead matter for at least the growing season (Scurlock et al. 2002). Site-description metadata, such as latitude, longitude, elevation, and information on vegetation type (biome), soil type, and land-use history were also desirable for inclusion for study sites in the compilation. Study sites were included that had at least one reference from the peer-reviewed literature.There are two data files in comma-separated (.csv) format with this data set.Revision Notes: Only the documentation for this data set has been modified from the original data set publication.
Advanced Modular, Multi-Channel, High Speed Fiber Optic Sensing System for Acoustic Emissions Monitoring Projectnasa-test-0.demo.socrata.com | Last Updated 2015-07-20T05:14:18.000Z
Intelligent Fiber Optic Systems Corporation (IFOS) proposes to prove the feasibility of innovations based on ultra-light-weight, ultra-high-speed, multi-channel, optical fiber sensor system for acoustics emissions (AE) monitoring for detection of impact damage and cracks in structural components in Aerospace structures. The project goals are to design an ultra-high-speed/high resolution with a small foot print fiber Bragg grating (FBG) sensor interrogator, construct a system model, test platform including embedded FBG sensors and develop signal processing algorithms to identify and measure AE signals in the presence of a quasi-static background strain field. The system model will demonstrate proof-of-principle and the test results will provide proof-of-functionality of the proposed sensor system for monitoring AE including using the advanced fiber optic sensor signal processing algorithms. AE will be simulated in an Aluminum by performing pencil break or impact hammer tests. The model test results will be compared to the measurements made concurrently by a standard single channel piezoelectric AE transducer. IFOS and its collaborators in this project will develop a Phase II strategy plan that includes development and integration strategy, potential demonstration opportunities, program schedule, and estimated costs. The key proposed innovation is a modular, light-weight, ultra-high-speed, multi-channel, optical fiber sensor system for AE monitoring.