Live coverage: Atlas 5 countdown and launch journal

A sophisticated combat-ready U.S. military missile warning satellite moved to its launch pad at Cape Canaveral Space Force Station Saturday on top of a United Launch Alliance Atlas 5 rocket, ready for liftoff Monday afternoon.

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 Russian Soyuz rocket rolled out to a launch pad in Kazakhstan early Thursday in preparation for liftoff Saturday with a Russian commander, Italian flight engineer and U.S. astronaut heading for the International Space Station.