On April 9th at 12:53 P.M., United Launch Alliance launched the final Delta IV Heavy rocket from SLC-37 after a scrubbed launch attempt on March 28th due to a Ground Support Equipment (GSE) issue. Delta IV Heavy will launch the NROL-70 mission, which is a classified satellite for the National Reconnaissance Office (NRO). Delta IV Heavy will be replaced with ULA's Vulcan rocket which made its inaugural launch in January 2024.