Live coverage: Atlas 5 countdown and launch journal

United Launch Alliance has begun stacking its first Atlas 5 rocket to fly in service to the International Space Station, a commercial mission to send supplies to the orbiting complex.

A SpaceX Falcon 9 rocket lifted off from Vandenberg Space Force Base in California at 12:26 p.m. PDT (3:26 p.m. EDT; 1926 GMT) Friday with another batch of 52 Starlink internet satellites. The mission is the first of two SpaceX launches scheduled Friday, with another Falcon 9 poised for liftoff from Florida a little more than four hours later.

Boeing and SpaceX are readying for launch abort tests in the coming weeks to validate the crew escape systems for the new human-rated Starliner and Crew Dragon spaceships, now scheduled to begin ferrying astronauts to the International Space Station in the first half of next year.