The Landsat program is the longest running enterprise for acqusition of imagery of Earth from space. The first Landsat satellite was launched in 1972; the most recent, Landsat 7, was launched on April 15, 1999. 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, geology, forestry, regional planning, education and national security.

History

The program was called the Earth Resources Observation Satellites Program when it was initiated in 1966, but the name was changed to Landsat in 1975. In 1979 Presidential Directive 54 (Carter) transferred Landsat operations from NASA to NOAA, recommended development of long term operational system with four additional satellites beyond Landsat 3, and recommended transition to private sector operation of Landsat. This occurred in 1985 when the Earth Observation Satellite Company (EOSAT), a partnership of Hughes and RCA, was selected by NOAA to operate the Landsat system under a ten year contract. EOSAT operated Landsats 4 and 5, had exclusive rights to market Landsat data, and was to build Landsats 6 and 7.

A simulated-color satellite image of Kolkata taken on NASA's Landsat 7 satellite.

In 1989 this transition had not been fully completed when NOAA's funding for the Landsat program ran out and NOAA directed that Landsats 4 and 5 be shut down, but an act of Congress provided emergency funding for the rest of the year. Funding ran out again in 1990 and once again Congress provided emergency funding to NOAA for six more months of operations, requesting that agencies that used Landsat data provide the funding for the other six months of the upcoming year. The same funding problem and solution was repeated in 1991. In 1992 various efforts were made to finally procure funding for follow on Landsats and continued operations, but by the end of the year EOSAT ceased processing Landsat data. Landsat 6 was finally launched on October 5 1993, but was lost in a launch failure. Processing of Landsat 4 and 5 data was resumed by EOSAT in 1994. NASA finally launched Landsat 7 on April 15, 1999.

The value of the Landsat program was recognized by Congress in October, 1992 when it passed the Land Remote Sensing Policy Act (Public Law 102-555) authorizing the procurement of Landsat 7 and assuring the continued availabilty of Landsat digital data and images, at the lowest possible cost, to traditional and new users of the data.

• Landsat 1 (originally named Earth Resources Technology Satellite 1) - launched July 23 1972, terminated operations in 1978
• Landsat 2 - launched January 22 1975, terminated in 1981
• Landsat 3 - launched March 5 1978, terminated 1983
• Landsat 4 - launched July 16 1982, terminated 1993
• Landsat 5 - launched March 1 1984, still functioning [1] [2]
• Landsat 6 - launched October 5 1993, failed to reach orbit
• Landsat 7 - launched April 15, 1999, still functioning [3]

Landsat 7 has a 15m to 30m resolution.