The 1992 Land Remote Sensing Policy Act identifies data continuity as the fundamental goal of the Landsat program. The scientific mission of Landsat 7 is entirely consistent with this legislated goal. The mission is to extend and improve upon the more than 26-year record of images of the Earth's continental surfaces provided by the earlier Landsat satellites. The continuation of this work is an integral component of the U.S. Global Change Research Program. Landsat 7 also will continue providing essential land surface data to a broad, diverse community of civil and commercial users.
Landsat Science History
The first Landsats, originally called ERTS for Earth Resources Technology Satellite, were developed and launched by NASA between July 1972 and March 1978. During that time, a second generation of Landsat satellites was developed. Landsat 4 was launched in July 1982 and Landsat 5 in March 1984. Landsat 5 is still transmitting images. Landsat 7 was authorized by a Presidential Directive signed by President Bush in 1992.