Today, a United Launch Alliance Atlas V rocket is scheduled to launch at 10:44PM ET. The launch window extends half an hour, to 11:14PM ET. Aboard is the $1.1 billion Magnetosperic Multiscale mission, or MMS, a series of four identical observatories, tasked with exploring the magnetic fields over Earth.
The mission will be studying magnetic reconnection, which taps into energy in the magnetic field and converts it to heat — "usually explosively," as NASA puts it. The phenomenon can damage satellites; it also causes the Northern and Southern Lights, the aurorae around the Earth's poles. The four satellites will fly in a pyramid formation, so that the 100 instruments on board can help scientists better understand magnetic reconnection.
Each spacecraft, once it spreads its of its 60-meter-long (197-foot-long) antennae out, is about the size of a baseball diamond. The satellites will be ejected singly, and then will fly in orbits as close as 2,600 km (1,600 miles) from Earth. At their farthest, after about a year and a half, they may fly as high as 152,000 km (95,000 miles) from our planet's surface, according to Spaceflight Now.