Waterside view of Delta 4 GPS 2F-6 Launch

A United Launch Alliance Delta 4 rocket blasted off from Vandenberg Air Force Base in California at 3:40 a.m. local (6:40 a.m. EST; 1140 GMT) today to place a secret payload into space for the National Reconnaissance Office. Follow the mission in our live journal.

The issue with a gaseous nitrogen pipeline that caused the late March launch scrub was able to be resolved, according to NASA and its contractor, Air Liquide. Liftoff from Space Launch Complex 37 occurred at 12:53 p.m. EDT (1653 UTC).

The launch from Cape Canaveral of a top secret spy satellite for the U.S. government was aborted at the last moment early Saturday as its United Launch Alliance Delta 4-Heavy rocket ignited three main engines, a dramatic cutoff of the countdown that will delay the mission by at least one week.