Landsat is a series of Earth observation satellites operated by the United States Geological Survey (USGS) and the National Aeronautics and Space Administration (NASA). NASA is responsible for designing, building, launching, and testing the satellites, and USGS is responsible for operating the satellites, collecting and archiving data, and distributing data to users worldwide. Landsat satellites have been collecting information about the Earth for over 40 years, since 1972, providing valuable data for the United States and the rest of the world, thus becoming a cornerstone of global land imaging.

The program was established, in 1972, with the launch of Landsat 1, which was then known as the Earth Resources Technology Satellite (ERTS-1). There have been 9 Landsat missions launched since 1972, with Landsat 9 being the most recent launch in September 2021. Landsat 9 is currently operational, and the previous mission, Landsat 8, is still running and producing data. The satellites orbit the Earth in a polar orbit, which allows them to cover the entire globe every 16 days.

The Landsat program has created an extensive archive of remotely sensed data of the Earth’s surface, which is the longest continuous record available. It has provided a wealth of historical data, allowing for long-term studies of changes in the Earth’s land surface over time, with data being used by scientists, researchers, government agencies, and the private sector worldwide. In particular, the program has been instrumental in advancing our understanding of land use and land cover change, including deforestation, urbanization, and natural disasters.

Landsat data is publicly available for free. Managed by both NASA and the U.S. Geological Survey, the Landsat satellite missions are a key component of the country’s remote sensing capability and have helped to establish the United States as a leader in land imaging technology.

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Landsat Missions

There have been nine Landsat missions to date, with each mission carrying a different sensor or set of sensors:

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TECHNICAL DETAILS

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Landsat 1 through 6 were launched between 1972 and 1993, and while they are no longer operational, they did provide valuable data for several decades.

• Landsat 1 through 5 carried the Multispectral Scanner (MSS) instrument, which had four spectral bands with a spatial resolution of 80 meters.
• Landsat 4 and 5 also carried the Thematic Mapper (TM) instrument, which had seven spectral bands with a spatial resolution of 30 meters.
• Landsat 6 was the only Landsat mission that failed to reach orbit, and no data was collected from that mission.
• The Landsat 7 satellite also carried the Enhanced Thematic Mapper Plus (ETM+), which had 8 spectral bands.
• Landsat 8 and 9 satellites carry several instruments, but the primary sensor is the Operational Land Imager (OLI) which has 9 spectral bands ranging from visible to thermal infrared wavelengths. The Thermal Infrared Sensor (TIRS) is another important instrument that captures thermal radiation in two spectral bands.

The spatial resolution of Landsat imagery is 30 meters for most bands, except for the panchromatic band on Landsat 8 and 9, which has a resolution of 15 meters. Landsat 8 and 9 have an improved radiometric resolution of 12 bits, which allows for up to 4,096 levels of gray in each band. The spectral resolution varies by band, with Landsat 8 and 9 OLI having 8 multispectral bands covering visible to shortwave infrared wavelengths and the TIRS instrument capturing data in two thermal infrared bands. The temporal resolution of Landsat data is around 16 days, meaning each location on Earth is imaged about once every 16 days, weather permitting.

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Landsat 1-3

Landsat 1, 2, and 3 were launched in 1972, 1975, and 1978, respectively. These missions carried the Multispectral Scanner (MSS) instrument, which had four spectral bands with a spatial resolution of 80 meters. The bands were named:

• Band 4: Green (0.5-0.6 µm)
• Band 5: Red (0.6-0.7 µm)
• Band 6: Near Infrared (0.7-0.8 µm)
• Band 7: Near Infrared (0.8-1.1 µm)

The temporal resolution of these missions was 18 days.

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Landsat 4-5

Landsat 4 and 5 were launched in 1982 and 1984, respectively, and carried the Thematic Mapper (TM) instrument in addition to the MSS. The TM had seven spectral bands with a spatial resolution of 30 meters. The bands were named:

• Band 1: Blue (0.45-0.52 µm)
• Band 2: Green (0.52-0.60 µm)
• Band 3: Red (0.63-0.69 µm)
• Band 4: Near Infrared (0.76-0.90 µm)
• Band 5: Mid-Infrared (1.55-1.75 µm)
• Band 6: Thermal Infrared (10.4-12.5 µm)
• Band 7: Mid-Infrared (2.08-2.35 µm)

The temporal resolution of these missions was 16 days.

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Landsat 6

Landsat 6 was launched in 1993 but failed to reach orbit, and no data was collected.

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Landsat 7

Landsat 7 was launched in 1999 and carried the Enhanced Thematic Mapper Plus (ETM+) instrument, which had eight spectral bands with a spatial resolution of 30 meters. The bands were named:

• Band 1: Blue (0.45-0.52 µm)
• Band 2: Green (0.52-0.60 µm)
• Band 3: Red (0.63-0.69 µm)
• Band 4: Near Infrared (0.77-0.90 µm)
• Band 5: Mid-Infrared (1.55-1.75 µm)
• Band 6: Thermal Infrared (10.4-12.5 µm)
• Band 7: Mid-Infrared (2.09-2.35 µm)
• Band 8: Panchromatic (0.52-0.90 µm)

The temporal resolution of Landsat 7 is 16 days. The ETM+ instrument has a panchromatic band with a spatial resolution of 15 meters.

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Landsat 8-9

Landsat 8-9 Landsat 8 was launched in 2013 and carries the Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) instruments. Landsat 9, launched in 2021, also carries these instruments. Both satellites have a combined 11 spectral bands with a spatial resolution of 30 meters. Landsat 8-9’s OLI instrument has a 12th band, a panchromatic band with a spatial resolution of 15 meters. The bands are named:

• Band 1: Coastal/Aerosol (0.43-0.45 µm)
• Band 2: Blue (0.45-0.51 µm)
• Band 3: Green (0.53-0.59 µm)
• Band 4: Red (0.64-0.67 µm)
• Band 5: Near Infrared (0.85-0.88 µm)
• Band 6: Shortwave Infrared 1 (1.57-1.65 µm)
• Band 7: Shortwave Infrared 2 (2.11-2.29 µm)
• Band 8: Panchromatic (0.50-0.68 µm)
• Band 9: Cirrus (1.36-1.38 µm)
• Band 10: Thermal Infrared 1 (10.60-11.19 µm)
• Band 11: Thermal Infrared 2 (11.50-12.51 µm)

The OLI instrument has nine spectral bands that provide improved signal-to-noise ratio, radiometric quantization, spatial resolution, and calibration compared to previous Landsat sensors. The TIRS instrument has two thermal bands that operate in the long-wave infrared region and provide measurements of land surface temperature.

The temporal resolution of Landsat 8-9 is 16 days.

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The main technical details are summarized in the following Tables.

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The long-term, consistent nature of Landsat data makes it especially valuable for monitoring changes in the Earth’s surface over time. Landsat data has been used to track changes in land use over time, monitor forest health and wildfire activity, identify agricultural crop types, assess crop health, and monitor changes in urban areas.

Among the main applications Landsat data have been used for:

• Land cover and land use classification
• Urban expansion assessment
• Forest and crop monitoring
• Water resource management
• Natural disaster response and recovery
• Climate change studies

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The USGS provides free access to Landsat data through their EarthExplorer web portal. The data is available in various formats, including GeoTIF, and can be downloaded by selecting the area of interest and date range. The USGS also provides a LandsatLook Viewer, which allows users to view and download full-resolution, pre-selected Landsat scenes without the need for specialized software. Additionally, the USGS offers a range of Landsat analysis tools and datasets, including surface reflectance data and cloud-free composites.

Data can be downloaded in several different digital formats and processed using a variety of software packages, including ArcGIS and QGIS.

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RELATED LINKS AND ADDITIONAL RESOURCES

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Further background information about Landsat

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• Landsat Science – This is the USGS Landsat Science website, which provides information on the science behind Landsat missions. It includes sections on Landsat data, applications, and research.
• Landsat Program – This is the NASA Landsat Program website, which provides information on the history and science of Landsat missions. It includes sections on Landsat data, applications, and education.
• Landsat Education – This USGS website provides educational resources and materials related to Landsat missions. It includes sections on Landsat history, data, and applications, as well as lesson plans and educational materials for teachers.
• Landsat Handbook – This is the USGS Landsat Handbook, which provides a comprehensive overview of Landsat missions and data. It includes sections on Landsat history, sensors, data products, and applications, as well as technical information and data access instructions.

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Accessing and working with Landsat data

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• USGS EarthExplorer – This is the main portal for searching and downloading Landsat data. It allows users to search for and download data by location, date range, and other criteria.
• USGS LandsatLook Viewer – This viewer provides access to full-resolution, pre-selected Landsat scenes without requiring specialized software. Users can select an area of interest and browse through available scenes.
• USGS Landsat Analysis Ready Data – This page provides information on the Landsat Analysis Ready Data (ARD) product, which is a processed dataset that includes surface reflectance and other derived products. The ARD product is designed to be easier to work with and more consistent than raw Landsat data.
• USGS Landsat Collection 2 Level-2 – This page provides information on the Landsat Collection 2 Level-2 product, which includes surface reflectance and other derived products. The Level-2 product is designed to be easier to work with and more consistent than raw Landsat data.
• Google Earth Engine – Google Earth Engine is a cloud-based platform for working with geospatial data, including Landsat data. It provides access to pre-processed Landsat data and a range of analysis tools.
• NASA Land Processes Distributed Active Archive Center – This center provides access to Landsat data and other remote sensing data products. It also offers a range of tools and resources for working with remote sensing data.
• ESA Sentinel Online – While not Landsat data, the Sentinel satellites operated by the European Space Agency (ESA) offer similar data products and applications. This website provides information on the Sentinel missions and access to data.

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*Images from

https://svs.gsfc.nasa.gov/Gallery/Landsat.html