Soyuz (Russian: Союз, lit. 'union', as in Soviet Union, GRAU index: 11A511) is a family of Soviet and later Russian expendable, medium-lift launch vehicles initially developed by the OKB-1 design bureau and has been manufactured by the Progress Rocket Space Centre in Samara, Russia. The Soyuz family holds the record for the most launches in the history of spaceflight. Most Soyuz rockets are part of the R-7 rocket family, which evolved from the R-7 Semyorka, the world's first intercontinental ballistic missile. As with several Soviet launch vehicles, the names of recurring payloads became closely associated with the rocket itself. The Soyuz rocket became widely recognized as the launcher of crewed Soyuz spacecraft under the Soyuz programme, and of the derivative uncrewed Progress cargo spacecraft. Despite this recognition, the majority of Soyuz launches have been dedicated to deploying satellites for both governmental and commercial purposes. All Soyuz variants use RP-1 (kerosene) and liquid oxygen (LOX) as propellants, with the exception of the Soyuz-U2, which used Syntin (a refined kerosene variant) with LOX. Between the retirement of the Space Shuttle in 2011 and the first crewed flight of SpaceX's Crew Dragon in 2020, Soyuz rockets were the only certified launch vehicles capable of transporting astronauts to and from the ISS.
History
Development
The first Soyuz launcher was introduced in 1966. It was derived from the earlier Vostok launcher, which in turn had been based on the R-7 Semyorka, the world's first intercontinental ballistic missile. The Soyuz used a three-stage design with the Block I third stage. Its first four test flights ended in failure, but subsequent missions achieved success. A four-stage variant, the Molniya, was developed by adding an additional upper stage, enabling launches into highly elliptical Molniya orbits. A later evolution, the Soyuz-U, became the workhorse of the family. During the Cold War, the exact Soviet model designations were not publicly available. In the West, the United States Department of Defense referred to the Soyuz launcher as SL-4, while Charles Sheldon of the Library of Congress devised the A-2 designation. Both systems were eventually abandoned as more accurate information became available. Production of Soyuz rockets peaked at about 60 units per year in the early 1980s. By the 21st century, the Soyuz had become the world's most frequently used space launcher, with more than 1,700 flights. Despite its age, the family has remained in service due to its comparatively low cost, high reliability, and proven performance.
Soyuz / Fregat
In the early 1990s plans were made for a redesigned Soyuz with a Fregat upper stage. The Fregat engine was developed by NPO Lavochkin from the propulsion module of its Phobos interplanetary probes. Although endorsed by Roscosmos and the Russian Ministry of Defence in 1993 and designated "Rus" as a Russification and modernization of Soyuz, and later renamed Soyuz-2, a funding shortage prevented implementation of the plan. The creation of Starsem in July 1996 provided new funding for the creation of a less ambitious variant, the Soyuz-Fregat or Soyuz-U/Fregat. This consisted of a slightly modified Soyuz-U combined with the Fregat upper stage, with a capacity of up to 1,350 kilograms (2,980 lb) to geostationary transfer orbit. In April 1997, Starsem obtained a contract from the European Space Agency (ESA) to launch two pairs of Cluster II plasma science satellites using the Soyuz-Fregat. Before the introduction of this new model, Starsem launched 24 satellites of the Globalstar constellation in 6 launches with a restartable Ikar upper stage, between 22 September 1999 and 22 November 1999. After successful test flights of Soyuz-Fregat on 9 February 2000 and 20 March 2000, the Cluster II satellites were launched on 16 July 2000 and 9 August 2000. Another Soyuz-Fregat launched the ESA's Mars Express probe from Baikonur in June 2003.
ISS crew transport Between 1 February 2003 and 26 July 2005 with the grounding of the United States Space Shuttle fleet, Soyuz was the only means of transportation to and from the International Space Station. This included the transfer of supplies, via Progress spacecraft, and crew changeovers. After the retirement of the Space Shuttle fleet in 2011, the United States space program was without any means to take astronauts into orbit, and NASA was dependent on the Soyuz to send crew into space until 2020. NASA resumed crewed flights from the United States in 2020 through the Commercial Crew Development program.
Recent incidents A long streak of successful Soyuz launches was broken on 15 October 2002 when the uncrewed Soyuz-U launch of the Photon-M satellite from Plesetsk fell back near the launch pad and exploded 29 seconds after lift-off. One person from the ground crew was killed and eight were injured. Another failure occurred on 21 June 2005, during a Molniya military communications satellite launch from the Plesetsk launch site, which used a four-stage version of the rocket called Molniya-M. The flight ended six minutes after the launch because of a failure of the third stage engine or an unfulfilled order to separate the second and third stages. The rocket's second and third stages, which are identical to the Soyuz, and its payload (a Molniya-3K satellite) crashed in the Uvatsky region of Tyumen (Siberia). On 24 August 2011, an uncrewed Soyuz-U carrying cargo to the International Space Station crashed, failing to reach orbit. On 23 December 2011, a Soyuz-2.1b launching a Meridian 5 military communications satellite failed in the 7th minute of launch because of an anomaly in the third stage. On 11 October 2018, the Soyuz MS-10 mission to the International Space Station failed to reach orbit after an issue with the main booster. Four payload mounted solid rocket jettison motors were used to pull the Soyuz spacecraft away from the malfunctioning rocket, as the main launch abort system tower had been jettisoned.The two crew, Aleksey Ovchinin and Nick Hague, followed a ballistic trajectory and landed safely over 400 km downrange from the Baikonur Cosmodrome.
Soyuz 2
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