Dynamics Explorer

Dynamics Explorer was a NASA mission, launched on August 3, 1981 and terminated on February 28, 1991. It consisted of two unmanned satellites, DE-1 and DE-2, whose purpose was to investigate the interractions between plasmas in the magnetosphere and those in the ionosphere. The two satellites were launched together into polar coplanar orbits, which allowed them to simultaneously observe the upper and lower parts of the atmosphere.