MMS is the fourth mission in the NASA Solar Terrestrial Probes Program. Goddard built, integrated and tested the four MMS spacecraft and is responsible for overall mission management and operations. The principal investigator for the MMS instrument suite science team is based at the SwRI. Science operations planning and instrument commanding are performed at the MMS Science Operations Center at the University of Colorado Boulder’s Laboratory for Atmospheric and Space Physics. 

The PI for the mission is James Burch of the Southwest Research Institute. The Solving Magnetospheric Acceleration, Reconnection, and Turbulence (SMART) team counts other U.S. institutions as well as partners in Europe and Japan.

Read more about the mission at the MMS Quick Facts sheet at link)

Quoting from the MMS public oureach website:

'MMS will reveal, for the first time, the small-scale three-dimensional structure and dynamics of the elusively thin and fast-moving electron diffusion region. It will do this in both of the key reconnection regions near Earth, where the most energetic events originate.
The four identically instrumented MMS spacecraft will fly in an adjustable pyramid-like formation that will allow them to observe the three-dimensional structure of magnetic reconnection. MMS sensors will measure charged particle velocities, as well as electric and magnetic fields, with unprecedented (milliseconds) time resolution and accuracy needed to capture the elusively thin and fast-moving electron diffusion region. MMS probes reconnection of solar and terrestrial magnetic fields in the dayside and nightside of Earth's magnetosphere, the only natural laboratory where it can be directly observed by spacecraft.'