A Delta 4-Heavy rocket stands on its launch pad Friday at Vandenberg Space Force Base, California, ready for liftoff on the NROL-91 mission for the National Reconnaissance Office. Credit: United Launch Alliance
United Launch Alliance will move out of historic Space Launch Complex 6 at Vandenberg Space Force Base in California following the flight of a Delta 4-Heavy rocket set for Saturday, leaving the military to find a new tenant for the storied launch pad once intended to host space shuttle missions on the West Coast.