CAPE CANAVERAL, Fla. — NASA has launched four identical spacecraft on a billion-dollar mission to study the explosive give-and-take of the Earth and sun’s magnetic fields.

An unmanned Atlas rocket blasted off Thursday night from Cape Canaveral, Florida, carrying NASA’s Magnetospheric Multiscale spacecraft.

The observatories will be placed into an oblong orbit stretching tens of thousands of miles into the magnetosphere. Magnetic reconnection is what happens when magnetic fields come together, break apart, then come together again, releasing vast energy.

This repeated process drives the aurora, as well as solar storms that can disrupt communications and power on Earth. Data from this two-year mission should help scientists better understand so-called space weather.

The findings from the $1.1 billion mission will be useful in understanding magnetic reconnection throughout the universe. Closer to home, space weather scientists along with everyone on Earth hopefully will benefit.