Photos: Atlas 5 rolls out for launch

A replay of the United Launch Alliance Atlas 5 rocket launching the Air Force’s X-37B reusable spaceplane from Cape Canaveral, Florida.

NASA officials cleared Boeing’s Starliner spacecraft for flight Thursday after a “thorough and comprehensive” review of the crew capsule’s readiness, setting the stage for final pre-launch preparations at Cape Canaveral ahead of liftoff Dec. 20 on an unpiloted demonstration mission to the International Space Station.

This is the ascent timeline to be followed by the Atlas 5 rocket’s ascent into orbit from Vandenberg Air Force Base in California with the commercial WorldView 4 Earth-imaging satellite for DigitalGlobe. Launch is scheduled for Friday at 11:30 a.m. local time (2:30 p.m. EDT; 1830 GMT).