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Michael Hesse: The MMS Mission is a mission
consisting of 4 spacecraft which will fly in close constellation
to measure a process called magnetic reconnection.
John Dorelli: The universe is full of plasma and it's full of magnetic fields,
and all over the place in the universe,
you have one plasma colliding with another. An example of that is
the solar wind coming in and colliding with Earth's magnetosphere.
The magnetic energy in the plasma, some fraction of that
of the magnetic energy is converted very rapidly into plasma energy.
You can think of it as kind of like a magnetic explosion.
The reason this is important is
these explosions drive a lot of the weather
patterns that we see in the magnetosphere, so what space scientists
like to refer to as space weather.
These space weather phenomena can have impact
on our every day lives. It can actually affect communications
satellites, the power grid. So, we would really like to understand
how these magnetic explosions work.
Michael Hesse: We need to measure magnetic reconnection in more than one location.
Basically, how it varies in space, how it varies
all 3 spacial dimensions. That requires a
a tetrahedron. The additional, fantastic benefit
that that provides is that it will actually enable
us to recognize that we are looking at a reconnection region
much easier than a single spacecraft. John Dorelli: The idea situation
we would like the 4 spacecraft to kind of be surrounding
this region where the explosion is happening.
The separation of the spacecraft is about 10 - 100 kilometers, which makes
it may seem like a long distance, but in terms of the magnetosphere,
which is absolutely huge, this is really a microscopic
region we are trying to cover. Micheal Hesse: MSS has, in a nutshell,
2 orbital phases which are designed to study
reconnection.
John Dorelli: On the day side, you have situation where the solar wind is just constantly running
into Earth's magnetic field. This is really great for MMS,
because we know at some point MMS is going
encounter this region. Our hope is that
since this process is always happening we are gonna get lucky
and actually fly right through the magnetic
explosion as it is happening. Now, on the nightside,
the situation is a little bit different. What happens you have a more
gradual build up of magnetic energy in the tale,
and these reconnection processes, these magnetic explosions,
can just sort of pop off randomly
we don't really know when it's gonna happen or when it's gonna happen in the tail.
Michael Hesse: We need to understand both of those, if we want to understand how the magnetophere works
And we believe that both of those scenarios are also very important for us
for other applications, such as on the sun,
in the solar wind, in planetary magnetospheres,
and many astrophysical objects
as well as in the laboratory. John Dorelli: We hope that is going to allow us to improve
our models so that we can put the right physics in it
and actually make predictions about where and when reconnection
is going to happen, and this will help us make our space weather models more predicatively powerful
The instruments that are actually going to be measuring
the particles in space are collecting them much more rapidly
at a much higher cadence than they have
on previous missions, by about a factor of 100.
Whereas it would, you know a previous generation particle instrument
about 3 or 4 seconds
to build up a whole picture of the sky, it's going to take
MMS about 30 milliseconds.
So, it really is sort of game changing technology.
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