Soyuz (cohete) version
Soyuz (cohete) Soyuz-U (11A511U)
The most-launched rocket in history: 786 flights between 1973 and 2017, almost 44 years of continuous service. The «U» stands for unified, because it replaced both the Voskhod and the original Soyuz. It placed 6,900 kg into low Earth orbit from Baikonur.
- May 18, 1973
- First launch
- 6,900 kg
- LEO capacity
- No
- Reusable
History
Unifying production
By the mid-1970s the Soviet Union was flying Molniya, Voskhod and several Vostok models alongside the original Soyuz. The Soyuz-U, designed by the TsSKB bureau and built at the Progress factory in Samara, was introduced as a single platform: the «U» stands for unified. Full adoption came only in 1977, when the remaining stock of earlier Soyuz boosters ran out, and even then the Vostok-2M and Molniya-M kept covering specialised high-orbit missions.
Record numbers
The first Soyuz-U flew on 18 May 1973 with Kosmos 559, a Zenit military surveillance satellite. The last lifted off on 22 February 2017 carrying Progress MS-05 to the International Space Station. In between it logged 786 launches with 765 successes, more flights than any carrier rocket ever built. Production of R-7 derived launchers peaked in the late 1970s and early 1980s at 55–60 a year; in 1979 the Soyuz-U set the world record for launch rate with 47 flights in a year, a mark that stood until Falcon 9 beat it in 2022.
Configurations and descendants
Two versions carried an additional upper stage: the Soyuz-U/Ikar, with the Progress-built Ikar stage, and the Soyuz-U/Fregat, with Lavochkin's Fregat, which flew four times in 2000 and whose stage later flew regularly on Soyuz-FG and Soyuz-2. The Soyuz-U itself was the base for the Soyuz-U2 and the Soyuz-FG. From 2013 it was progressively replaced by the modernised Soyuz-2.