Oldest active rocket family

The oldest rocket family that is still operational is the Soviet/Russian R-7 series, which includes the Soyuz rockets currently used to launch crew to the International Space Station. All the rockets in this family are ultimately derived from the R-7 Semyorka, the first intercontinental ballistic missile, which first flew on 15 May 1957.

Rockets are often grouped into "families", which represent various different configurations and upgrades of the same basic design. Each rocket family represents a set of shared technologies and engineering philosophies that have contributed to each iteration of the design.

The career of the R-7 ICBM was actually fairly short, as the nuclear weapons it was designed to launch were soon replaced by much smaller, lighter models that did not require such a powerful and complex launch vehicle. Its lift capacity, however, made it ideal for use in the Soviet Union's embryonic space program. Modified R-7 rockets were used to launch both the Sputnik satellite and Yuri Gagarin first crewed mission, before being further modified to create the Soyuz and Molniya launch vehicles.

The closest rival to the R-7 family is the American Thor/Delta series, derived from the Thor IRBM, which made its first successful launch on 20 Sep 1957. The longest-lived model in this family was the Delta II, which made 153 launches between 1990 and 2018.