Snapshots from Atlas 5 launch

Launch of an Atlas 5 rocket from Cape Canaveral with a U.S. Air Force infrared surveillance satellite was scrubbed Thursday evening after engineers encountered a balky valve associated with the first stage’s liquid oxygen system.

A United Launch Atlas 5 rocket is set to loft three military satellites for the U.S. Air Force on a mission codenamed AFSPC 11. This timeline shows the major mission events planned over a six-hour flight to a near-geostationary orbit.

The United Launch Alliance Atlas 5 rocket, standing 197 feet tall and and weighing 1.2 million pounds, unleashes 2.4 million pounds of thrust from its main engine and four solid-fuel boosters at 6:42 p.m. EST (2342 GMT) Saturday to launch the GOES-R weather observer for NASA and NOAA from Cape Canaveral, Florida.