A United Launch Alliance Delta 4-Heavy rocket launched a classified spy satellite cargo for the U.S. National Reconnaissance Office. The largest of the Delta 4 family, the Heavy version features three Common Booster Cores mounted together to form a triple-body rocket. This is the penultimate flight of a Delta 4 rocket. Delayed from March and April 20. Scrubbed June 21 due to ground pneumatic valve issue. Read our launch story.