Soyuz U

The Soyuz-U launch vehicle was an improved version of the original Soyuz rocket. Soyuz-U was 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 (now a united company, TsSKB-Progress). Soyuz-U was in use continuously for almost 44 years. Production of R-7 derived launch vehicles peaked in the late 1970s-early 1980s at 55–60 a year. Soyuz-U held the world record for the highest launch rate in a year in 1979 with 47 flights. Over its operational lifetime, the Soyuz-U variant flew a total of 786 missions, another world record.