Geotail is a satellite observing the Earth's magnetosphere. It was developed by Japan's ISAS in association with the United States' NASA, and was launched by a Delta II rocket on July 24, 1992. From the Geotail website (listed below): "The Geotail satellite was launched on July 24, 1992, by a Delta II launch vehicle from Cape Canaveral Air Force Station, Florida, United States. The primary purpose of this mission is to study the structure and dynamics of the tail region of the magnetosphere with a comprehensive set of scientific instruments. For this purpose, the orbit has been designed to cover the magnetotail over a wide range of distances: 8 R⊕ to 210 R⊕ from the earth. This orbit also allows us to study the boundary region of the magnetosphere as it skims the magnetopause at perigees.