Landsat 8 (formerly called the Landsat Data Continuity Mission, or LDCM) is NASA’s eighth satellite in the Landsat series and continues the Landsat program’s critical role in monitoring, understanding and managing the resources needed for human sustainment such as food, water and forests. As our population surpasses seven billion people, the impact of human society on the planet will increase, and Landsat monitors those impacts as well as environmental changes.
With the longest unbroken data stream of Earth’s surface as seen from space, NASA’s Earth-observing Landsat fleet has provided the world with unprecedented information on land cover changes and their residual effects since 1972. The knowledge gained from 40 years of continuous data contributes to research on climate, carbon cycle, ecosystems, water cycle, biogeochemistry and changes to Earth’s surface, as well as our understanding of visible human effects on land surfaces. Building off that research, the Landsat imaging data set has, over time, led to the improvement of human and biodiversity health, energy and water management, urban planning, disaster recovery and agriculture monitoring, all resulting in incalculable benefits to the United States and world economy.
Landsat 8 joined the Landsat 7 satellite in orbit and produces stunning pictures of Earth’s surface along with a wealth of scientific data. Landsat 8 measures Earth’s surfaces in the visible, near-infrared, short wave infrared and thermal infrared, with a moderate-resolution of 15 to 100 meters, depending on spectral frequency.
Landsat 8 is a collaboration between NASA and the U.S. Geological Survey (USGS).
he observatory consists of the spacecraft bus and its payload of two Earth observing sensors, the Operational Land Imager (OLI) and the Thermal Infrared Sensor (TIRS). OLI and TIRS will collect the LDCM science data. The two sensors will coincidently collect multispectral digital images of the global land surface including coastal regions, polar ice, islands, and the continental areas. The spacecraft bus will store the OLI and TIRS data on an onboard solid-state recorder and then transmit the data to ground receiving stations.
- Operational Land Imager(OLI)
The Operational Land Imager (OLI), built by the Ball Aerospace & Technologies Corporation, will measure in the visible, near infrared, and short wave infrared portions of the spectrum. Its images will have 15-meter (49 ft.) panchromatic and 30-meter multi-spectral spatial resolutions along a 185 km (115 miles) wide swath, covering wide areas of the Earth's landscape while providing sufficient resolution to distinguish features like urban centers, farms, forests and other land uses. The entire Earth will fall within view once every 16 days due to LDCM’s near-polar orbit.
- Thermal Infrared Sensor(TIRS)
The Thermal Infrared Sensor (TIRS) will measure land surface temperature in two thermal bands with a new technology that applies quantum physics to detect heat.
TIRS was added to the satellite mission when it became clear that state water resource managers rely on the highly accurate measurements of Earth's thermal energy obtained by LDCM's predecessors, Landsat 5 and Landsat 7, to track how land and water are being used. With nearly 80 percent of the fresh water in the Western U.S. being used to irrigate crops, TIRS will become an invaluable tool for managing water consumption.
TIRS uses Quantum Well Infrared Photodetectors (QWIPs) to detect long wavelengths of light emitted by the Earth whose intensity depends on surface temperature. These wavelengths, called thermal infrared, are well beyond the range of human vision. QWIPs are a new, lower-cost alternative to conventional infrared technology and were developed at NASA’s Goddard Space Flight Center in Greenbelt, Md.
Referred by NASA(http://www.nasa.gov/mission_pages/landsat/overview/index.html