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

A collection of pad photos from the United Launch Alliance Atlas 5 rocket flight to deploy the Navy’s Mobile User Objective System communications satellite No. 4.

Ziplines are used by thrill-seekers in adventures around the world, but now they are coming to the U.S. space program as the emergency escape system for personnel at Cape Canaveral’s Complex 41.

The revised Atlas 5 rocket firing order includes two national security missions this summer before launching NASA’s daring asteroid sampler mission in September as originally planned.