Live coverage: Atlas 5 countdown and launch journal

United Launch Alliance technicians raised the first stage of the company’s next Atlas 5 rocket onto a mobile launch platform at Cape Canaveral Thursday, kicking off the launch vehicle’s build-up for a mission scheduled for liftoff May 16 with the U.S. military’s hush-hush X-37B spaceplane.

More testing will be done on both the thrusters on the spacecraft’s aft section. The Starliner crew will also repeat some previously conducted test activities, like the ‘safe haven’ protocol.

An accident Saturday during an abort engine test on a Crew Dragon test vehicle at Cape Canaveral sent a reddish-orange plume into the sky visible for miles around, a setback for SpaceX and NASA as teams prepare the capsule for its first mission with astronauts.