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Comparison of systems corrected ERTS-1 imagery and microdensitometer scan printouts derived from them with base vegetation maps and current 1:120,000 and 1:60,000 scale imagery of the Great Smoky Mountains is in progress. It reveals good separation of the spruce-fir forest from the other forest areas but band seven does not distinguish between hardwood and heath dominated vegetation.
Large electric field spikes of up to about 80 mV/m, at distances of seven to 23 earth radii, were detected within one minute of encountering the high-altitude plasma sheet boundary, as identified by energetic particle detectors. If these high-altitude events, whose strong electric fields occur in enhanced low-frequency turbulence and field-aligned current flow regions and are individually well-correlated with small-scale gradients in particle fluxes and small-scale currents, are mappings of the low-altitude electrostatic shocks, these data may be taken as evidence that poleward auroral field lines map to the boundary of the plasma sheet.
Using the empirical terrestrial magnetospheric magnetic field models of Tsyganenko and Usmanov (1982) and Tsyganenko (1987) the average field-aligned currents (FACs) in the magnetosphere were determined as a function of the Kp index. Three major model FAC systems were identified, namely, the dayside region 1, the nightside region 1, and the nightside polar cap. The models provide information about the sources of the current systems. Mapped ionospheric model FACs are compared with low-altitude measurements obtained by the spacecraft. It is found that low-altitude data can reveal either classic region 1/2 or more highly structured FAC patterns. Therefore, statistical results either obtained from observations or inferred from models are expected to be averages over temporally and spatially shifting patterns.
The Galactic Cosmic Ray spectra in Mars orbit were generated with the recently expanded HZETRN (High Z and Energy Transport) and QMSFRG (Quantum Multiple-Scattering theory of nuclear Fragmentation) model calculations. These model calculations are compared with the first eighteen months of measured data from the MARIE (Martian Radiation Environment Experiment) instrument onboard the 2001 Mars Odyssey spacecraft that is currently in Martian orbit. The dose rates observed by the MARIE instrument are within 10% of the model calculated predictions. Model calculations are compared with the MARIE measurements of dose, dose-equivalent values, along with the available particle flux distribution. Model calculated particle flux includes GCR elemental composition of atomic number, Z = 1-28 and mass number, A = 1-58. Particle flux calculations specific for the current MARIE mapping period are reviewed and presented.
INTRODUCTION: Following long-duration exploration transits, pressurized rovers will enhance surface mobility to explore multiple sites across Mars and other planetary bodies. Multiple rovers with docking capabilities are envisioned to expand the range of exploration. However, adaptive changes in sensorimotor and cognitive function may impair the crew s ability to safely navigate and perform docking tasks shortly after transition to the new gravitoinertial environment. The primary goal of this investigation is to quantify post-flight decrements in spatial navigation and docking performance during a rover simulation. METHODS: Eight crewmembers returning from the International Space Station will be tested on a motion simulator during four pre-flight and three post-flight sessions over the first 8 days following landing. The rover simulation consists of a serial presentation of discrete tasks to be completed within a scheduled 10 min block. The tasks are based on navigating around a Martian outpost spread over a 970 sq m terrain. Each task is subdivided into three components to be performed as quickly and accurately as possible: (1) Perspective taking: Subjects use a joystick to indicate direction of target after presentation of a map detailing current orientation and location of the rover with the task to be performed. (2) Navigation: Subjects drive the rover to the desired location while avoiding obstacles. (3) Docking: Fine positioning of the rover is required to dock with another object or align a camera view. Overall operator proficiency will be based on how many tasks the crewmember can complete during the 10 min time block. EXPECTED RESULTS: Functionally relevant testing early post-flight will develop evidence regarding the limitations to early surface operations and what countermeasures are needed. This approach can be easily adapted to a wide variety of simulated vehicle designs to provide sensorimotor assessments for other operational and civilian populations.
Colombia is a country with highly variable terrain, from the Andes Mountains to plains and coastal areas, many of these areas are prone to flooding disasters. To identify these risk areas NASA's Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) was used to construct a digital elevation model (DEM) for the study region. The preliminary risk assessment was applied to a pilot study area, the La Mosca River basin. Precipitation data from the National Aeronautics and Space Administration (NASA) Tropical Rainfall Measuring Mission (TRMM)'s near-real-time rainfall products as well as precipitation data from the Instituto de Hidrologia, Meteorologia y Estudios Ambientales (the Institute of Hydrology, Meteorology and Environmental Studies, IDEAM) and stations in the La Mosca River Basin were used to create rainfall distribution maps for the region. Using the precipitation data and the ASTER DEM, the web application, Mi Pronóstico, run by IDEAM, was updated to include an interactive map which currently allows users to search for a location and view the vulnerability and current weather and flooding conditions. The geospatial information was linked to an early warning system in Mi Pronóstico that can alert the public of flood warnings and identify locations of nearby shelters.
We introduce a new unified atmospheric–topographic correction approach that estimates surface geometry directly from the radiance measurement. Surface topography influences the at-sensor radiance measurement, making precise topography modeling critical in applications like vegetation or snow studies in mountainous terrain. Currently, elevation maps are used to derive topographic variables such as the slope and sky-view factor. This process is error-prone since static global digital elevation models do not generally achieve the accuracy required, and even minor mismatches in spatial resolution can introduce significant artifacts in downstream processing. Here we demonstrate that it is possible to estimate topographic parameters directly from spectral data, ensuring perfect physical consistency, temporal coincidence, and spatial alignment. We present experiments estimating topographic slope in two scenes in Southern California, with data from NASA’s Next Generation Airborne Visible/Near Infrared Imaging Spectrometer (AVIRIS-NG). We compared our radiance-based estimates against high-resolution lidar datasets. Our initial validation result showed a correlation of R 2 = 0.864 (n = 160) over the homogeneous surface of Beckman Auditorium’s cone-shaped roof on the Caltech campus in Pasadena, California. We then validate the model over a larger study site near Santa Clarita, California, finding R 2 = 0.923 (n = 40,000) in a 350 x 350m area. The accuracy of our model estimates, combined with its systematic advantages over the alternative, show the potential of the approach for use in both airborne campaigns and orbital missions.
We are currently investigating new technological developments in computer visualization and analysis in order to assess their importance and utility in planetary geological analysis and mapping [1,2]. Last year we reported on the range of technologies available and on our application of these to various problems in planetary mapping [3]. In this contribution we focus on the application of these techniques and tools to Venus geological mapping at the 1:5M quadrangle scale. In our current Venus mapping projects we have utilized and tested the various platforms to understand their capabilities and assess their usefulness in defining units, establishing stratigraphic relationships, mapping structures, reaching consensus on interpretations and producing map products. We are specifically assessing how computer visualization display qualities (e.g., level of immersion, stereoscopic vs. monoscopic viewing, field of view, large vs. small display size, etc.) influence performance on scientific analysis and geological mapping. We have been exploring four different environments: 1) conventional desktops (DT), 2) semi-immersive Fishtank VR (FT) (i.e., a conventional desktop with head-tracked stereo and 6DOF input), 3) tiled wall displays (TW), and 4) fully immersive virtual reality (IVR) (e.g., "Cave Automatic Virtual Environment," or Cave system). Formal studies demonstrate that fully immersive Cave environments are superior to desktop systems for many tasks [e.g., 4].
The effect of collector, guard-ring potential imbalance on the observed collector-current-density J, collector-to-emitter voltage V characteristic was evaluated in a planar, fixed-space, guard-ringed thermionic converter. The J,V characteristic was swept in a period of 15 msec by a variable load. A computerized data acquisition system recorded test parameters. The results indicate minimal distortion of the J,V curve in the power output quadrant for the nominal guard-ring circuit configuration. Considerable distortion, along with a lowering of the ignited-mode striking voltage, was observed for the configuration with the emitter shorted to the guard ring. A limited-range performance map of an etched-rhenium, niobium, planar converter was obtained by using an improved computer program for the data acquisition system.
The current state of far-infrared astronomy drives the need to develop compact, sensitive spectrometers for future space and ground-based instruments. Here we present details of the µ-Spec spectrometers currently in development for the far-infrared balloon mission EXCLAIM. The spectrometers are designed to cover the 555 – 714 µm range with a resolution of R = λ/∆λ = 512 at the 638 µm band center. The spectrometer design incorporates a Rowland grating spectrometer implemented in a parallel plate waveguide on a low-loss single-crystal Si chip, employing Nb microstrip planar transmission lines and thin-film Al kinetic inductance detectors (KIDs). The EXCLAIM µ-Spec design is an advancement upon a successful R = 64 µ-Spec prototype, and can be considered a sub-mm superconducting photonic integrated circuit (PIC) that combines spectral dispersion and detection. The design operates in a single M=2 grating order, allowing one spectrometer to cover the full EXCLAIM band without requiring a multi-order focal plane. The EXCLAIM instrument will fly six spectrometers, which are fabricated on a single 150 mm diameter Si wafer. Fabrication involves a flip-wafer-bonding process with patterning of the superconducting layers on both sides of the Si dielectric. The spectrometers are designed to operate at 100 mK, and will include 355 Al KID detectors targeting a goal of NEP ∼8 × 10−19 W/√( Hz). We summarize the design, fabrication, and ongoing development of these µ-Spec spectrometers for EXCLAIM.
A block of 24 overlapping synthetic aperture side-looking radar images flown over a well mapped area of about 90,000 sq km provided an opportunity to evaluate the mapping accuracy achieved in current radar mosaicking projects. The maps of scale 1:24,000 that are available in the imaged area permitted the study of the geometric errors of the radar mosaics and of individual radar strips. An estimate was obtained for the effect of the distribution and density of ground control points and for the accuracy of different mosaicking methods that are currently employed with synthetic aperture radar images. It is shown that a successful radar mosaicking process requires the elimination of image errors of up to several kilometers. These errors are introduced as a result of the limited precision of the inertial aircraft navigation. An example of a radar mapping effort in which the navigation errors could be eliminated is presented. The resulting radar mosaics have residual RMS mapping errors of planimetry of about plus or minus 150 m.
Mappymatch is a pure-python package developed and open sourced by the National Renewable Energy Laboratory. It contains a collection of "Matchers" that enable matching a GPS trace (series of GPS coordinates) to a map. As of 8/14/2023, The current matchers are: LCSSMatcher: A matcher that implements the LCSS algorithm described in this paper. Works best with high resolution GPS traces. OsrmMatcher: A light matcher that pings an OSRM server to request map matching results. See the official documentation for more info. ValhallaMatcher: A matcher to ping a Valhalla server for map matching results. Currently supported map formats are: Open Street Maps NOTE: This software was formerly known as YAMM (Yet Another Map-Matcher)
We present a global MHD magnetospheric simulation of the encounter of the magnetic cloud with the terrestrial magnetosphere on January 10-11, 1997. The MHD simulation is driven by IMF and solar wind plasma measurements provided by Wind situated about 100 $R_E$ upstream from Earth. Field-aligned currents produced in the model are mapped down to the ionosphere and are directly compared to auroral images from the Polar UVI. Particular attention will be paid to the interval following the the initial shock wave arrival (around 0100 UT on the 1Oth) but preceding the passage of the magnetic cloud proper (commencing at about 0430 UT) for which there was continuous viewing of the entire auroral oval from apogee by Polar. This turbulent period is characterized by numerous dynamic pressure rises and dips and several northward and southward turnings of the IMF, all of which generate dynamic activity in the simulation that is reflected in the mapped field-aligned current patterns. As discussed by Brittnacher et al. in this session, the auroral morphology imaged by UVI during this period includes: shock wave-induced brightening of the oval followed by a pseudo-onset near midnight, several sun-aligned and curled arcs within the polar cap, an expanding polar cap cleared of arcs, and finally substorm onset at 0337 UT. These features will be directly compared to region 1 and 2 current systems as well as cusp currents in the simulation. Spacecraft magnetopause crossings are also predicted by the global simulation and will be compared to observed crossings, including numerous dayside crossings by Geotail on the 1Oth, and geosynchronous crossings early on January 11.
NASA's Hall Effect Rocket with Magnetic Shielding (HERMeS) 12.5kW Technology Demonstration Unit-3 (TDU-3) has been the subject of extensive technology maturation in preparation for flight system development. Detailed performance, stability, and plume characterization tests of the thruster were performed at NASA GRC's Vacuum Facility 5 (VF-5). The TDU-3 thruster implements a magnetic topology that is identical to TDU-1. The TDU-3 boron nitride silica composite discharge channel material is different than the TDU-1 heritage boron nitride discharge channel material. Performance and stability characterization of the TDU-3 thruster was performed at discharge voltages between 300V and 600V and at discharge currents between 5A and 21.8A. The thruster performance and stability were assessed for varying magnetic field strength, cathode flow fractions between 5% and 9%, varying harness inductance, and for reverse magnet polarity. Performance characterization test results indicate that the TDU-3 thruster performance is in family with the TDU-1 levels. TDU-3's thrust efficiency of 65% and specific impulse of 2,800sec at 600V and 12.5kW exceed performance levels of SOA Hall thrusters. Thruster stability regimes were characterized with respect to the thruster discharge current oscillations (discharge current peak-to-peak and root mean square magnitudes), discharge current waveform power spectral density analysis, and maps of the current-voltage-magnetic field. Stability characterization test results indicate a stability profile similar to TDU-1. Finally, comparison of the TDU-1 and TDU-3 plume profiles found that there were negligible differences in the plasma plume characteristics between the TDU with heritage boron nitride versus the boron nitride silica composite discharge channel.
A two-dimensional 128 x 128 detector array for the 1.0 - 1.7 micron spectral region has been demonstrated with indium gallium arsenide. The 30 micron square pixels had 60 micron spacing in both directions and were designed to be compatible with a 2D Reticon multiplexer. Dark currents below 100 pA, capacitance near 0.1 pF, and quantum efficiencies above 80 percent were measured. Probe maps of dark current and quantum efficiency are presented along with pixel dropout data and wafer yield which was as high as 99.89 percent (7 dropouts) in an area of 6528 pixels and 99.37 percent (103 dropouts) over an entire 128 x 128 pixel region.
Species distribution models have often been hampered by poor local species data, reliance on coarse-scale climate predictors and the assumption that species-environment relationships, even with non-proximate predictors, are consistent across geographical space. Yet locally accurate maps of invasive species, such as the Africanized honeybee (AHB) in North America, are needed to support conservation efforts. Current AHB range maps are relatively coarse and are inconsistent with observed data. Our aim was to improve distribution maps using more proximate predictors (phenology) and using regional models rather than one across the entire range of interest to explore potential differences in drivers.
Electrochemical atomic force microscopy (EC-AFM) enables measurement of electrode topography and mechanical properties during electrochemical reactions. However, for aqueous-based reactions that make gas products, such as CO 2 reduction and water splitting into CO/H 2 , current densities below 1 mA cm −2 have been necessary to prevent formation of bubbles at the electrode; such bubbles can stick to the AFM probe and prevent further AFM imaging. Here, we demonstrate a novel cell design with a gas-diffusion electrode (GDE) to exhaust the gas products, thereby enabling high current density EC-AFM measurements at 1, 10, and 100 mA cm −2 that are not disturbed by bubble formation at the electrode surface. These experiments revealed a stable morphological structure of Cu catalysts deposited on GDEs during high current density operation. Systematic spatially resolved maps of deformation and adhesion showed no signs of a gas-liquid interface between catalyst particles of the GDE.
A system of processing remotely sensed multispectral scanner data by computer programs to produce color-coded land use maps for large areas is described. The procedure is explained, the software and the hardware are described, and an analogous example of the procedure is presented. Detailed descriptions of the multispectral scanners currently in use are provided together with a summary of the background of current land use mapping techniques. The data analysis system used in the procedure and the pattern recognition software used are functionally described. Current efforts by the NASA Earth Resources Laboratory to evaluate operationally a less complex and less costly system are discussed in a separate section.