Soyuz-U

Soyuz-U was a Soviet and later Russian expendable medium-lift launch vehicle, designed by the TsSKB design bureau and built at the Progress factory in Samara. The U stands for unified: it replaced the Voskhod rocket and several earlier Soyuz variants, bringing the many R-7 derived rockets then in use onto a single platform with upgraded RD-117 and RD-118 engines that reduced in-flight vibration and combustion instability. It belongs to the R-7 rocket family that grew out of the first intercontinental ballistic missile. The first flight was on 18 May 1973 with the Kosmos 559 satellite, and the last was on 22 February 2017 with Progress MS-05 bound for the International Space Station. Over almost 44 years it flew 786 missions, a record, with a 97.3 percent success rate, and 47 launches in 1979 stood as a yearly record until 2022. Variants added Ikar or Fregat upper stages.