Video: Take a virtual ride on the Atlas 5 launch pad emergency ziplines

After years of delays, the core stage for NASA’s first Space Launch System moon rocket rolled out of its New Orleans factory Wednesday, heading for a NASA site in Mississippi for a test-firing before engineers hope to ship the rocket to its Florida launch base by this fall.

A United Launch Alliance Atlas 5 rocket blasted off from Vandenberg Air Force Base in California at 5:49 a.m. local time (8:49 a.m. EDT; 1249 GMT) Thursday on the classified National Reconnaissance Office NROL-55 mission.

The addition of a U.S. Air Force communications satellite has capped the assembly of a 218-foot-tall United Launch Alliance Delta 4 rocket at Cape Canaveral set for liftoff the evening of March 13.