The Dynamics Explorer (DE) mission's general objective is to
investigate the strong interactive processes coupling the hot,
tenuous, convecting plasmas of the magnetosphere and the
cooler, denser plasmas and gases corotating in the earth's
ionosphere, upper atmosphere, and plasmasphere. Two
satellites, DE 1 and DE 2, were launched together and were
placed in polar coplanar orbits, permitting simultaneous
measurements at high and low altitudes in the same field-line
region.