The mobile service tower retracts from the Atlas 5 rocket, revealing the 191-foot-tall vehicle for liftoff from Vandenberg Air Force Base, California, carrying the classified NROL-79 national security payload for the U.S. government.

Closing out a five-week mission, a SpaceX Dragon cargo craft departed the International Space Station on Saturday. The spaceship will dive back into Earth’s atmosphere, deploy parachutes and splash down in the Pacific Ocean at 3:39 p.m. EDT (1939 GMT) about 265 miles west of Baja California.

A new satellite launched Aug. 1 has joined the U.S. Air Force’s GPS navigation network to help guide everything from bombs to road trippers to their destinations, with final preparations on track to send up another GPS spacecraft at the end of October.