Photos: Atlas 5 rolls out for launch

SpaceX’s second Falcon Heavy rocket is set for liftoff Thursday from NASA’s Kennedy Space Center in Florida, and the heavy-lift launcher will head on an easterly course over the Atlantic Ocean atop more than 5 million pounds of thrust.

United Launch Alliance scrubbed the launch of a Delta 4-Heavy rocket Wednesday night less than 10 seconds before liftoff from Cape Canaveral, the second such abort suffered by this mission.. The launch of a classified National Reconnaissance Office spy satellite is expected to be delayed at least several more days as engineers assess the cause of Wednesday’s last-minute abort.

Launching the sixth mission of the U.S. military’s super-secret X-37B spaceplane program, a United Launch Alliance Atlas 5 rocket lifted off Sunday morning from Cape Canaveral and successfully delivered its clandestine cargo to orbit.