Soyuz rockets

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Soyuz rockets are with over 1700 flights since 1966, the most frequently used rocket in the world. After the end of the US Space Shuttle program in 2011, Soyuz rockets became the only possibility to transport astronauts to the ISS (International Space Station).

The Soyuz rockets are used as the launcher for the manned Soyuz spacecraft, as well as to unmanned Progress supply cargo to the ISS, or earlier space stations Salyut, Mir. All Soyuz rockets use RP-1 (Rocket Propellant - 1, similar to jet fuel, used as a rocket fuel) and liquid oxygen propellant with the exception of the Soyuz-U2, which used Syntin (variant of RP-1, it has higher density, lower viscosity and higher specific heat of oxidation).  

R-7 Semyorka: drawing

Soyuz rockets are subset of R-7 family of rockets, derived from R-7 Semyorka developed during the Cold War as first intercontinental ballistic missile. It launched the first satellite Sputnik 1 into the low orbit in modified version. It became a basis for the R-7 family of rockets including Sputnik, Luna, Molnia (military communication satellites), Vostok, Voskhod, and Soyuz space launchers. 


Some variants:
R-7 Semyorka first launched on May 15, 1957 and last launched on February 27, 1961 with 27 attempts from which was 18 successful. 
R-7A Semyorka first launched on December 23, 1959 and last launched on July 25, 1967, with 21 attempts which was 18 successful. 



8K71PS Sputnik launch vehicle. 

Soyuz rockets were derived from Vostok launcher in 1966. Initially it was 3 stage rocket with a Block I upper stage. After Molniya version, the fourth stage was added. 

 Soyuz variants:

 Soyuz 11A511 (1966-1975) first launched 8 unmanned test flights, which was followed by the first 19 manned launches. It also launched 4 test flights of Soyuz 7K-T between 1972 and 1974. It had 30 successful launches and it had only two failures over 10 years. 
Soyuz-L 11A511L (1970-1971) was designed to launch test LK lunar lander to low Earth's orbit and it was part of the cancelled Soviet lunar program. 
Soyuz-M 11A511M (1971-1976) was supposed developed for manned military purposes. After cancellation of that program, the purpose of the launcher moved for the Soyuz 7K-S spacecraft. After the cancellation of this program as well, the whole development of the rockets were closed as well and that rockets which were already finished were used to launch reconnaissance satellites (unofficial spy satellites, communications satellite deployed for military purposes). 
Soyuz-U 11A511U (1973-2017) was first launched on May 18, 1973 carrying Kosmos 559 and Zenit. The last flight was on February 22, 2017 carrying Progress MS-05 to ISS. The success rate was 97.3 per cent. 
  • Soyuz-U/Ikar version has Ikar third stage. The performance of Ikar is lower than performance of the Fregat upper stage, but it has better precision in maneuvering. It is used for Progress. 
  • Soyuz-U/Fregat version had Fregat as the third stage and was flown only 4 times in 2000. The Fregat upper stage was regularly flown atop Soyuz-FG and Soyuz-2 rockets. 
Soyuz-U2 11A511U2 or 11A511K (1982-1995) was developed from the Soyuz-U and had better performance due to use of syntin instead of RP-1. The increased performance allowed to get heavier spacecraft to the normal orbit, or to get lighter spacecraft to the higher orbit. U2 got retired in 1996 due to syntin high cost. 
Soyuz.FG 11A511U-FG (2001-now) made the first flight on May 20, 2001 carrying Progress M1-6 cargo spacecraft to the ISS (International Space Station). Since October 30, 2002 Soyuz-FG was the only launched of manned Soyuz-TMA and Soyuz-MS spacecraft to the ISS. Another version is the Soyuz-FG/Fregat with Fregat as the third stage with commercial payloads.  
Soyuz-2 14A14 (2016-now) is the new version of Russian rockets. It replaced Molniya-M since 2010 and it is replacing gradually Soyuz-U and Soyuz-FG. In May 2018 was announced that launches of Soyuz from Guiana may be replaced by the Ariane 6 (launch vehicle developed by ESA, first test flight scheduled in 2020) in 2021. 

Stages: 3
First stage of Soyuz rockets consists of 4 identical liquid booster rockets, strapped to the second stage. Each booster rocket has a single rocket engine with 4 combustions chambers, two vernier combustion chambers, and one set of turbopumps. A vernier thruster is a rocket engine used for fine adjustments. 
Second stage of Soyuz single, cylindrical stage with one engine at the base and it is activated with the first stage. It has 4 combustion chambers and one set of turbopumps and 4 vernier combustion chambers. 
Third stage has two variants Block I and Improved Block I. 

Comparison of thrusts, first and second stages have about 800 to 1020 kN (lift off to vacuum thrust) and third stage has about 300 kN. First stage has 44.5 t, second stage has 105.4 t, and the third stage 25.2 t. 

Soyuz rocket engines (first and second stage)
credit Russian spaceweb: launch profile


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