ULA

The Delta II rocket first launched in 1989, making it the oldest US orbital launch system still flying today. However, the heritage of this launch system is much older still. The Delta II rocket’s first stage is derivative of the Thor intermediate range ballistic missile—the first operational ballistic missile used by the United States Air Force in the 1950s. Thus, the Delta II rocket can trace its roots to the beginning of US rocketry.

But now the end is near for the Delta II rocket. For United Launch Alliance, it is costly to keep supply lines open for the medium-lift rocket (three to six tons to low-Earth orbit) that has flown just three times since 2012. On Saturday morning, the Delta II made its penultimate launch by carrying the first Joint Polar Satellite System spacecraft into orbit for NASA and NOAA. The flight occurred from Vandenberg Air Force Base in California.