"Having received the green light on our design during NASA's Critical Design Review, we are moving out on full implementation of our instrument," said Cathy Richardson, the instrument manager of the Thermal Infrared Sensor (TIRS), which will be built at the Goddard Space Flight Center in Greenbelt, Md.
TIRS is one of two instruments flying on the Landsat Data Continuity Mission (LDCM), the next generation in a series of satellites that have provided multispectral data of Earth's surface for more than 38 years. TIRS and the Operational Land Imager (OLI), being built by Ball Aerospace & Technologies Corp in Boulder, Colo., will extend Landsat's unparalleled record of Earth's changing landscapes.
NASA plans to launch LDCM in December 2012 as the follow-on to Landsat-7, launched in 1999. Landsat 7 and 5, launched in 1984, are continuing to supply images and operating beyond their design lives. As with preceding Landsat missions, the U.S. Geological Survey (USGS) will operate LDCM and maintain its data archive once it begins observations.
The 236-kg (525-lb.) TIRS is a two-channel thermal imager, providing 100-meter (328 feet) spatial resolution across a 185 km (115 mile) field-of-view. Both Landsats-5 and -7 provide thermal data, and the addition of TIRS will extend the Landsat database in the thermal infrared bands needed by a variety of users.
Thermal data are used operationally to monitor such things as water consumption on a field-by-field basis in the U.S. West mainly for agricultural purposes, said LDCM project scientist Jim Irons. TIRS will continue providing surface-temperature readings considered vital in a technique that resource managers in Idaho and other western states use to measure water use through evapotranspiration. As its name implies, evapotranspiration combines the evaporation of water into the atmosphere and the water vapor released by plants through respiration. "A transpiring plant is cooler than the surrounding area," Irons said. "If a forest is dry, it will not transpire and it will be warmer."
Western resource managers see the measurement technique as the most effective way to determine who is consuming water because it more accurately defines how much water is being removed from the system by a given individual or entity. Since adopting the technique, which its developers call METRIC for Mapping EvapoTranspiration with High Resolution and Internalized Calibration, resource managers report that the technique has helped resolve conflicts over water consumption among farmers irrigating their fields.
Landsat thermal data also are used to map urban heat fluxes for air-quality monitoring, assess volcano hazards, detect and screen clouds, track lake thermal plumes from power plants, map burn areas and assess wildfire risks, and identify mosquito-breeding areas.
TIRS will provide the infrared surface-temperature data with high-sensitivity, cryogenically cooled, Quantum Well Infrared Photodetector (QWIP) arrays, a detector technology that Goddard engineer Murzy Jhabvala developed over nearly two decades. With various funding sources, Jhabvala had matured the technology and had even created years earlier a one-million-pixel array that could sense a range of longer wavelength bands — more robust than the TIRS requirement of 10.5 to 12.5 micrometers. TIRS is the first spaceflight instrument to use the technology.
"Instrument developers selected the QWIP technology because it could easily meet the instrument's performance requirements and production schedule," Jhabvala said, adding that he and his team began working on the detector system in July 2008.
In particular, TIRS will carry three 640 x 512 QWIP arrays that are made of Gallium Arsenide semiconductor chips layered with more than 100 layers of detector material. The layers act as quantum wells, which trap electrons — the fundamental particles that carry an electric current — so that only light with a specific energy can release them. If the light with the correct energy hits one of the quantum wells in the array, the freed electron flows through a separate readout chip above the array where it is recorded. A computer uses this information to create an image of the infrared source. Fabricators can build a detector to sense specific wavelength bands by varying the composition and thickness of the layers.
Jhabvala and his team qualified the technology for actual spaceflight last August, and plan to deliver the detector system this November for integration into the instrument.For more information on the LCDM, visit:
Equipping form with function
23.06.2017 | Institute of Science and Technology Austria
Can we see monkeys from space? Emerging technologies to map biodiversity
23.06.2017 | Forschungsverbund Berlin e.V.
An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.
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Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...
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23.06.2017 | Physics and Astronomy
23.06.2017 | Physics and Astronomy
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