Photos: Atlas 5 on the pad awaiting liftoff on NROL-52

A groundbreaking Friday ceremonially commenced construction of an astronaut access tower at United Launch Alliance’s Atlas 5 launch pad in Florida, a 200-foot-tall gantry that will add to the future of U.S. human spaceflight.

The 100th flight of America’s Evolved Expendable Launch Vehicle program — a United Launch Alliance Atlas 5 rocket — departed Cape Canaveral on Saturday evening carrying the most advanced U.S. weather satellite ever made.

A United Launch Alliance Atlas 5 rocket lifted off from Vandenberg Air Force Base in California at 9:49:51 a.m. local time (12:49:51 p.m. EST; 1749:51 today to deploy a covert U.S. national security payload. Follow the ascent in our live journal.