NASA's Magnetospheric Multiscale (MMS) observatories are shown here

The U.S. National Aeronautics and Space Administration (NASA) Thursday was set to send four identical spacecraft on a mission to study the explosive give-and-take of the Earth and sun's magnetic fields.
Liftoff of the unmanned rocket and NASA's Magnetospheric Multiscale spacecraft is set for late Thursday night. Forecasters put the odds of good weather at 70 percent.
The spacecraft will be launched into an oblong orbit stretching thousands of kilometers into the magnetosphere and will fly in pyramid formation to provide three-dimensional views of magnetic reconnection on the smallest of scales.
Magnetic reconnection is what occurs when magnetic fields like those around Earth and the sun come together, break apart, then come together again, releasing vast energy. The repeated process drives the aurora, as well as potentially disruptive solar storms.