On December 14, 2006, a Delta II rocket launched from VAFB (Vandenberg Air Force Base) SLC-2 (Space Launch Complex 2) on the NROL-21 mission. This launch marked the first mission for ULA (United Launch Alliance) and the beginning of its 15-year history.
The Delta rocket family has three more launches before being phased out with the Vulcan-Centaur rocket. Delta has seen an extensive history with operations of nearly 65 years and operating in two different countries. Delta started its life in two different rockets during the late 1950s.