The Dynamics Explorer (DE) mission's general objective was 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.
The DE 1 spacecraft (high-altitude mission) used an elliptical orbit selected to allow:
- measurements extending from the hot magnetospheric plasma through the plasmasphere to the cool ionosphere
- global auroral imaging, wave measurements in the heart of the magnetosphere, and crossing of auroral field lines at several Earth radii
- measurements for significant periods along a magnetic field flux tube
The DE 2 spacecraft (low-altitude mission) complemented the high-altitude mission DE 1 and was placed into an orbit with a perigee sufficiently low to permit measurements of neutral composition, temperature, and wind.