The cooperative satellite mission, Geotail, was launched recently by the Institute of Space and Astronautical Science of Japan and NASA. This satellite will investigate the magnetotail region of the Earth's magnetosphere, reaching distances as large as 220 RE (1 Earth radii = 6378 km). In this orbit, Geotail will yield an increased understanding of fundamental processes taking place in this relatively unexplored portion of geospace.
The Geotail satellite was designed and developed by ISAS and was launched by NASA on a DELTA II expendable launch vehicle on July 24, carrying scientific instruments provided by both space agencies. This article describes briefly the Geotail mission objectives, as well as the mission design.