Nimbus program
The Nimbus satellites were second-generation meteorological research and development (R&D) spacecraft designed to serve as stablized, Earth-oriented platforms for the testing of advanced systems to sense and collect atmospheric science data. Seven Nimbus spacecraft have been launched into near-polar, Sun-synchronous orbits beginning with Nimbus 1 on August 28, 1964. On board the Nimbus satellites are various instrumentation for imaging, sounding, and other studies in different spectral regions.
Operation History of the Nimbus Satellites