Timeline of Earth science satellites

High Quality Content by WIKIPEDIA articles! The Timeline of Earth science satellites shows, in chronological order, those successful satellites with a program of Earth science. Sputnik 1, while the first satellite ever launched, did not conduct Earth science. Explorer 1 was the first satellite to make an Earth science discovery when it found the Van Allen belts. In the context of spaceflight, a satellite is an object which has been placed into orbit by human endeavor. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon.