Video: Falcon 9 launch replays

A little more than a year after the Falcon Heavy rocket’s first test flight, SpaceX teams on Florida’s Space Coast are readying the world’s most powerful operational launcher for its second mission Thursday with a commercial communications satellite.

The United Launch Alliance Delta 4 rocket blasts into the predawn skies at Vandenberg Air Force Base with the NROL-45 payload for the U.S. National Reconnaissance Office.

A new European satellite carrying instruments to track changes in the world’s oceans, measure receding ice sheets and chart vegetation growth climbed into orbit Wednesday on top of a Russian Rockot launcher.