• World record for highest number of launches in a single year: 47 launches
  • World record for total number of missions in lifetime: 786 launches
  • Streak of consecutive successful launches: 112 launches

The above is some of the achievement of the mighty Soyuz-U rocket! This is one of the few rockets that will hold its records for a long time.

Soyuz 18 booster on the launch pad 1 at the Baikonur complex in Kazakhstan, USSR. Photo credits: NASA
Soyuz 18 booster on the launch pad 1 at the Baikonur complex in Kazakhstan, USSR. Photo credits: NASA

The Soyuz-U launch vehicle was an improved version of the original Soyuz rocket developed in Russia. Soyuz-U was part of the R-7 family of rockets based on the R-7 Semyorka missile. The first Soyuz-U flight took place on 18 May 1973, carrying as its payload Kosmos 559, a Zenit military surveillance satellite The final flight of a Soyuz-U rocket took place on 22 February 2017, carrying Progress MS-05 to the International Space Station and with that ended a beautiful saga of 44 years of Soyuz-U.

Design

The rocket was developed in the early 1960s by space engineering firm OKB-1, which at the time was headed by Sergei Korolev. He had also designed the R-7 rocket which laid the platform for the development of the Vostok rocket, carrying Yuri Gagarin into space. Within the span of 5 years he created the Voskhod and Soyuz rockets but unfortunately he died in January 1966 and never saw the Soyuz rocket in operation.

Soyuz insertion timeline. Credits: European Space Agency
Soyuz insertion timeline. Credits: European Space Agency

Soyuz is composed of a lower portion consisting of four boosters (first stage) and a central core stage (second stage); and an upper portion, composed of a third stage, payload adapter and fairings. Liquid oxygen and kerosene are used as propellants for the complete Soyuz launch vehicle.

The four first stage boosters are assembled laterally around the second stage central core. The boosters and the second stage central core are ignited simultaneously on the ground. The second stage also has 4 vernier thrusters to help in 3-axis flight control after booster separation.

This engine differs from those of the boosters by the presence of four vernier thrusters, which are necessary for three-axis flight control after booster separation. After the second stage’s work is over, the third stage engine ignites and fires for ~240 seconds.