An early Earth Resources Technology Satellite (ERTS), 1975.
© National Aeronautics & Space Administration / Science & Society
The first of this series of satellites, used to monitor the surface of the Earth at various wavelengths from the visible to the infrared, was launched on 23rd July 1972. The satellites, the first three of which were structurally similar to the Nimbus meteorological satellites, were renamed Landsat early in the programme. Five Landsats were launched between 1972 and 1984 to study the Earth with a resolution of about 30 metres. The Landsat programme is an ongoing one. Landsat 7, launched in 1999 is able to view the Earth's surface at a resolution of 15 metres, and the next satellite, Landsat 8, is scheduled to be launched into orbit in 2005. The satellites are used to provide information for map making, studies of land use, pollution monitoring and mineral prospecting.