Hi, I'm John Dorelli. I'm a space scientist at NASA's Goddard Space Flight Center.
I'd like to tell you a little bit about NASA's MMS mission.
MMS was designed to study a phenomenon known as magnetic reconnection,
which is kind of a magnetic explosion in 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 phenomenon 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 capture the magnetic explosions
somewhere inside this tetrahedron. At closest approach to Earth, the
tetrahedron is highly stretched, and not suitable for capturing the magnetic explosions.
But by the time we get out to 76,000 kilometers, MMS will be
in nearly perfect formation, the four spacecraft separated by only
ten kilometers. The Sun is constantly blowing out its atmosphere
into space, and this solar wind meets Earth's magnetic field at 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 while in perfect formation.
As it crosses the magnetopause, MMS will take
high-speed snapshots of the magnetic explosions as they unfold.
[ whoosh ] [beep beep... beep beep... beep beep...]
[ beep beep... beep beep... beep beep... ]