MMS was designed to study a phenomenon known as magnetic reconnection. Which is
kind of a magnetic explosion space. You can think of Earth as a giant bar magnet
with magnetic lines of force emanating out into space in a dipole pattern. Under
just the right conditions energy in this magnetic field is explosively converted
into plasma energy creating spectacular space weather phenomena like the aurora
and magnetic storms. To catch these explosions in action the MMS orbits were
designed in two phases; a day side phase and a night side phase.
MMS is actually four identical spacecraft flying in a geometrical
formation known as a tetrahedron. Scientists hope to catch the magnetic
explosions somewhere inside this tetrahedron. The Sun is constantly
blowing out its atmosphere into space. And this solar wind meets first magnetic
field with the magnetopause. Here at the magnetopause scientists expect to catch
magnetic reconnection in action. So the apogee of the orbit is designed so that
the tetrahedron cuts across the boundary twice per orbit following perfect
formation. As it crosses the magnetopause MMS will take high-speed snapshots of
the magnetic explosions as they unfold. MMS will complete its primary mission
about two years after its launch but scientists will be analyzing its data
for many years to come.