Official ULA feed, expected to go live at 2:15 pm EDT.
This is the final launch, both of the Delta IV Heavy and the Thor/Delta Missile/Rocket family as a whole. The first Thor missile launch attempt was January 26, 1957 with the first successful launch on September 20, 1957. The first Delta rocket launch attempt was May 13, 1960 with the first successful launch on August 12, 1960.