Landsat program

A false-color satellite image of Kolkata, India, from Landsat 7 in 2004, showing rivers, vegetated areas, and developed areas

A land cover map of the big island of Hawaii using 1999–2001 data from Landsat 7, showing black lava flows from Mauna Loa, grayish dormant Mauna Kea, a plume of smoke from active Kilauea, dark green tropical forests, and light green agricultural areas.

The Landsat program is the longest-running enterprise for acquisition of satellite imagery of Earth. It is a joint NASA / USGS program. On 23 July 1972, the Earth Resources Technology Satellite was launched. This was eventually renamed to Landsat 1 in 1975.^[1] The most recent, Landsat 9, was launched on 27 September 2021.

The instruments on the Landsat satellites have acquired millions of images. The images, archived in the United States and at Landsat receiving stations around the world, are a unique resource for global change research and applications in agriculture, cartography, geology, forestry, regional planning, surveillance and education, and can be viewed through the U.S. Geological Survey (USGS) "EarthExplorer" website. Landsat 7 data has eight spectral bands with spatial resolutions ranging from 15 to 60 m (49 to 197 ft); the temporal resolution is 16 days.^[2] Landsat images are usually divided into scenes for easy downloading. Each Landsat scene is about 115 miles long and 115 miles wide (or 100 nautical miles long and 100 nautical miles wide, or 185 kilometers long and 185 kilometers wide).