The state of the ITM system is strongly influenced by tidal, planetary, and gravity waves propagating upward from the lower atmosphere. In addition, both large and small-scale waves are generated in the auroral region during disturbed conditions. Wave dissipation serves as a significant energy and momentum source for the global ITM circulation and its evolution. Breaking gravity waves are responsible for global turbulence distributions in the ITM system which affect chemical composition. Extreme modifications of ITM thermal structure, composition, and wind systems also occur during magnetic disturbances. The ITM wind system generates global electric fields via the dynamo mechanism.

The ITM system is ordered in local solar time as well as longitude. A single satellite is not capable of providing fast enough precession in local time while providing adequate coverage in latitude. (The higher the orbital inclination, the slower the precession in local time. For instance, with a 73-degree inclination, a spacecraft will complete a 24-hour local time cycle in about 90 days; during this time most dynamical structures are averaged out.) The optimum solution to this problem is a multi- satellite mission which provides reasonable coverage in local time, longitude, and latitude. The multi-satellite approach, however, implies a very focused complement of measurements using light- weight instruments.

The ITM dynamics mission seeks to provide the first global measurement of the dynamical state of the atmosphere from about 60 km to 300 km including its temporal evolution. This is accomplished with four satellites in sun-synchronous or polar circular (~600 km) orbits, providing limb profile measurements on both sides of the spacecraft separated by ~3 hours in local time, complemented by nadir images of small-scale structure at several altitudes. In-situ plasma drifts are also measured so that the ionospheric wind dynamo can be explored for the first time with simultaneous wind and drift measurements over the globe. This mission will also be the first to study the coupling between large- scale circulation and small-scale waves. Specific phenomena to be studied include mesosphere-thermosphere-ionosphere coupling by tidal and planetary waves; aurorally-generated waves and their global propagation; wave/wave and wave/mean-flow interactions at all altitudes; polar/auroral dynamics; global response to magnetic storms; solar quiet and disturbance ionospheric wind dynamos.