A United Launch Alliance Delta 4-Heavy rocket lifted off from Cape Canaveral at 8:09 p.m. EST Thursday (0109 GMT Friday). The long-delayed mission is carrying a classified spy satellite into orbit for the National Reconnaissance Office.

Watch a time-lapse video of the Atlas 5 rocket’s rollout at Cape Canaveral on Feb. 28, on the eve of liftoff with the GOES-S weather satellite.

Commercial ziplines have been installed and tested at United Launch Alliance’s Atlas 5 rocket pad as the emergency escape system if astronauts and ground personnel need to evacuate the Crew Access Tower.