"End of an Era: ULA's Final Delta IV Heavy Rocket Launches After 64 Years"

United Launch Alliance (ULA) launched its final Delta IV Heavy rocket, marking the end of a 64-year history of Delta rocket launches. The rocket carried a classified payload for the U.S. National Reconnaissance Office (NRO) and ignited a unique spectacle due to hydrogen buildup in the flame trench. ULA is retiring the Delta IV in favor of its newly introduced Vulcan rocket, designed specifically for national security space missions. The Delta rocket family has a storied legacy, with various versions and configurations contributing to significant space exploration milestones, and only a few Delta rockets are preserved in museums and rocket parks today.