The rocket was developed by USSA scientists and featured a nuclear-electric derivative propulsion system. The rocket also served as the last manned flight to the moon's surface, whereupon the crew recovered a flag belonging to the Valiant 12 Virgo III lunar lander that touched down on November 14, 1969. The craft's longest recorded space flight was 17 days, achieved during the Zeus 12 moon mission. With 77 successful launches recorded, the rocket was one of the most successful in U.S. Completed and launched in 2054, it was utilized for nearly 15 years before its conversion to military use, the crew and instruments within replaced with a nuclear warhead. The Delta IX rocket was commissioned in 2020 by the United States Space Administration.