NASA launches four spacecraft to solve magnetic mystery
Mar 13, 2015 4:30 PM -
Each observatory resembles a giant octagonal wheel, stretching more than 11 feet across and 4 feet high, and weighing 3,000 pounds apiece. Numbered and stacked like tires on top of the rocket for launch, No. 4 popped free first more than an hour after liftoff, followed every five minutes by another.