Delta IV MST rollback
VANDENBERG AIR FORCE BASE, Calif. -- The mobile service tower rolls back from the United Launch Alliance Delta IV Medium+ (5,2) rocket on Space Launch Complex 6 here Tuesday, April 3, 2012. This is the Department of Defense?s first-ever launch of a Delta IV configured with a 5-meter payload fairing and two solid rocket motors. (U.S. Air Force photo/Staff Sgt. Andrew Satran)