Orbital ATK awarded contract to extend Landsat mission
An artist’s rendition of Landsat 8 (LDCM). Image Credit: NASA
NASA awarded Orbital ATK a contract to build the next-generation Earth observation satellite, Landsat 9. The company will have five years to complete the $129.9 million delivery order, awarded under the Rapid Spacecraft Acquisition III (RAPID III).
Carrying Earth observations forward
Landsat 9 will continue the NASA-U.S. Geological Survey (USGS) program, which has provided 98-foot (30-meter) resolution of Earth’s surface and land use since 1972. Scientists use this data to track deforestation, farmland irrigation, urban growth, and other environmental conditions.
The newly contracted spacecraft is part of the joint NASA-USGS multi-satellite, multi-decadal, Sustainable Land Imaging (SLI) program. SLI is designed to develop, launch, and operate a spaceborne system that provides researchers and other users with high-quality, global, continuous land-imaging measurements.
Tools for viewing the world
At present, there are two Landsat spacecraft orbiting Earth: Landsat 7, launched in 1999, and Landsat 8, launched in 2013. Both satellites, flying in Sun-synchronous orbits 438 miles (705 km) above Earth, use multispectral imagers that observe land and water. Landsat 7 uses a passive scanning radiometer known as the Enhanced Thematic Mapper Plus, while Landsat 8 uses a passive imager called the Operational Land Imager (OLI) and a Thermal Infrared Sensor (TIR). The newly contracted spacecraft’s two instruments will mirror Landsat 8: an OLI built by Ball Aerospace & Technologies, and a TIR, which Goddard Space Flight Center will build.
OLI-2 will take measurements in the visible, near-infrared, and shortwave infrared portions of the electromagnetic spectrum. The spatial resolution of its images will be 49 feet (15 meters) for the panchromatic band and 98 feet (30 meters) for the multispectral bands. The image swath will be 115 miles (185 kilometers) wide, covering wide areas of the Earth’s landscape while providing sufficient resolution to distinguish land cover features like urban centers, farms, and forests. OLI-2 is a copy of Landsat 8’s OLI. It will provide visible and near-infrared/shortwave-infrared (VNIR/SWIR) imagery.
The new spacecraft’s Thermal Infrared Sensor 2 (TIRS-2) will measure land surface temperature in two thermal infrared bands using the same technology as Landsat 8’s TIRS. TIRS-2 uses principles of quantum physics to measure emissions of infrared energy. It will provide two spectral bands with a maximum ground sampling distance, both in-track and cross-track, of 328 feet (100 meters) for both bands. TIRS-2 provides an internal blackbody calibration source as well as space view capabilities.
Landsat 9 is scheduled to launch in 2020. However, a launch provider has not been determined. NASA will build, launch, and perform the initial checkout and commissioning of the craft while the USGS will operate, process, archive, and freely distribute the mission’s data. Once launched, the spacecraft will have a design life of five years. However, if it operates like most of NASA’s Earth observation satellites, it will be providing images of Earth much longer than that.
Bart Leahy
Bart Leahy is a freelance technical writer living in Orlando, Florida. Leahy's diverse career has included work for The Walt Disney Company, NASA, the Department of Defense, Nissan, a number of commercial space companies, small businesses, nonprofits, as well as the Science Cheerleaders.
OLI is not built by Orbital, but is actually built by Ball Aerospace who built the LandSat8 OLI unit.
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