Soyuz-U

The Soyuz-U launch vehicle (LV) is an improved version of the original Soyuz LV. Soyuz-U is part of the R-7 family of rockets based on the R-7 Semyorka missile. Members of this rocket family were designed by the TsSKB design bureau and constructed at the Progress Factory in Samara, Russia. (These two are now a united company, TsSKB-Progress). The first Soyuz-U flight took place on 18 May 1973, carrying as its payload Kosmos 559, a Zenit military surveillance satellite.

The earlier Soyuz 11A511 was the first attempt at creating a standardized R-7 core in place of the numerous variations that had been used up to 1966 and starting that year, the 11A511 Blok I and strap-on boosters were added to the 11A57, 8A92, and 8K78M vehicles as well as minor R-7 variants flown once or twice for specialized payloads.

Beginning in 1973, the uprated 11A511U core was introduced for the R-7 family although adoption across the board was not complete until 1977 when the existing stock of 11A511-derived boosters was used up.

Soyuz-U is still in use today, making several launches a year. Production of R-7 derived launch vehicles peaked in the late 1970s-early 1980 at 55-60 a year.