Photos: Delta 4 awaits blastoff

The Atlas rocket to launch four formation-flying spacecraft for NASA in March began to take shape Wednesday at the assembly building adjacent to the Complex 41 pad.

The United Launch Alliance Atlas 5 rocket stands atop Complex 41 at Cape Canaveral in readiness for the NROL-52 deployment mission for the National Reconnaissance Office.

United Launch Alliance called off a test-firing of the company’s first flight-rated Vulcan Centaur rocket at Cape Canaveral Thursday to troubleshoot a problem with the booster’s engine ignition system.