• 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.