Live coverage: Atlas 5 countdown and launch journal

The Atlas 5 rocket emerges from the Vertical Integration Facility for rollout to Complex 41 at Cape Canaveral in preparation to launch GPS 2F-12 satellite on Friday at 8:38 a.m. EST.

The Cargo Dragon spacecraft, tail number C209, will carry 6,659 lbs. (3,021 kg.) of science and supplies to the orbiting outpost. Liftoff from pad 39A at NASA’s Kennedy Space Center happened Monday, April 21, at 4:15 a.m. EDT (0815 UTC).

A SpaceX Dragon supply ship departed the International Space Station and returned to Earth Tuesday to conclude its third round-trip flight to the orbiting research outpost, bringing home a spacesuit, mice and and numerous experiments.