Live coverage: Atlas 5 countdown and launch journal

A United Launch Alliance Atlas 5 rocket lifted off from Cape Canaveral today at 7:42 p.m. EST (0042 GMT) to deploy the U.S. military’s SBIRS GEO Flight 3 observatory, equipped with advanced telescopic infrared vision to spot enemy missile launches, for early warning surveillance.

SpaceX’s Dragon supply ship reached the International Space Station on Wednesday, with astronaut Jeff Williams grappling the unpiloted spacecraft with the research lab’s robotic arm at 6:56 a.m. EDT (1056 GMT) after an automated rendezvous.

The 32-story-tall mobile service tower at the Delta 4’s launch pad at Vandenberg Air Force Base in California was retracted away from the rocket Thursday in advance of a planned liftoff with a top secret National Reconnaissance Office payload.