Yesterday, the largest operational rocket on the planet launched a classified payload for the US Navy's National Reconnaissance Office. Virtually nothing is known about the mission, but it is widely speculated to be an electronic signals intelligence (ELINT) spy satellite and one of the largest satellites to be put in orbit.
The launch was initially slated for Thursday, but poor weather forced a scrub, and a second attempt was made on Saturday. Liftoff occurred at 1:51pm.