 ASoyuz-FG rocket carrying theSoyuz TMA-9 spacecraft launches fromBaikonur Cosmodrome, Kazakhstan on 18 September 2006. | |
| Function | Medium-lift launch vehicle |
|---|---|
| Manufacturer | RKT Progress |
| Country of origin | Soviet Union · Russia |
| Size | |
| Stages | 3 |
| Associated rockets | |
| Family | R-7 |
| Launch history | |
| Status | Active |
| Launch sites | |
| First flight | 28 November 1966 |
| Carries passengers or cargo | Soyuz Progress |
Soyuz (Russian:Союз,lit. 'union', as inSoviet Union,GRAU index:11A511) is a family of Soviet and later Russianexpendable,medium-lift launch vehicles initially developed by theOKB-1 design bureau and has been manufactured by theProgress Rocket Space Centre inSamara, Russia. The Soyuz family holds the record for the most launches in the history of spaceflight. All Soyuz rockets are part of theR-7 rocket family, which evolved from theR-7 Semyorka, the world's firstintercontinental 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 crewedSoyuz spacecraft under theSoyuz programme, and of the derivative uncrewedProgress 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 useRP-1 (kerosene) andliquid oxygen (LOX) as propellants, with the exception of the Soyuz-U2, which usedSyntin (a refined kerosene variant) with LOX.
Between the retirement of theSpace Shuttle in 2011 and the first crewed flight ofSpaceX'sCrew Dragon in 2020, Soyuz rockets were the only certified launch vehicles capable of transporting astronauts to and from the ISS.
The first Soyuz launcher was introduced in 1966. It was derived from the earlierVostok launcher, which in turn had been based on theR-7 Semyorka, the world's firstintercontinental 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.[1]
A four-stage variant, theMolniya, was developed by adding an additional upper stage, enabling launches into highly ellipticalMolniya orbits. A later evolution, theSoyuz-U, became the workhorse of the family.[2]
During the Cold War, the exact Soviet model designations were not publicly available. In the West, theUnited States Department of Defense referred to the Soyuz launcher as SL-4, whileCharles Sheldon of theLibrary of Congress devised the A-2 designation.[3] 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.[4]
In the early 1990s plans were made for a redesigned Soyuz with aFregat upper stage. The Fregat engine was developed byNPO Lavochkin from the propulsion module of itsPhobos interplanetary probes. Although endorsed by theRoscosmos and theRussian 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 ofStarsem 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 modifiedSoyuz-U combined with the Fregat upper stage, with a capacity of up to 1,350 kilograms (2,980 lb) togeostationary transfer orbit. In April 1997,Starsem obtained a contract from theEuropean Space Agency (ESA) to launch two pairs ofCluster II plasma science satellites using the Soyuz-Fregat. Before the introduction of this new model, Starsem launched 24 satellites of theGlobalstar constellation in 6 launches with a restartableIkar 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, theCluster II satellites were launched on 16 July 2000 and 9 August 2000. Another Soyuz-Fregat launched the ESA'sMars Express probe from Baikonur in June 2003.
Between 1 February 2003 and 26 July 2005 with the grounding of the United StatesSpace 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, theUnited States space program was without any means to take astronauts into orbit, andNASA was dependent on the Soyuz to send crew into space until 2020.[5] NASA resumed crewed flights from the United States in 2020 through theCommercial Crew Development program.
A long streak of successful Soyuz launches was broken on 15 October 2002 when the uncrewedSoyuz-U launch of the Photon-M satellite fromPlesetsk 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.[citation needed]
Another failure occurred on 21 June 2005, during aMolniyamilitarycommunications satellite launch from the Plesetsk launch site, which used a four-stage version of the rocket calledMolniya-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 theUvatsky region ofTyumen (Siberia).[citation needed]
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 aMeridian 5 military communications satellite failed in the 7th minute of launch because of an anomaly in the third stage.[6]
On 11 October 2018, theSoyuz MS-10 mission to theInternational Space Station failed to reach orbit after an issue with the main booster. Thelaunch escape system was used to pull the Soyuz spacecraft away from the malfunctioning rocket. The two crew,Aleksey Ovchinin andNick Hague, followed a ballistic trajectory and landed safely over 400 km downrange from theBaikonur Cosmodrome.[citation needed]
The venerable Soyuz-U launcher was gradually replaced by a new version, namedSoyuz 2, which has a new digital guidance system and a highly modified third stage with a new engine. The first development version of Soyuz 2 calledSoyuz 2.1a, which is equipped with the digital guidance system, but is still propelled by an old third stage engine, started on 4 November 2004 fromPlesetsk on a suborbital test flight, followed by an orbital flight on 23 October 2006 from Baikonur. The fully modified launcher (versionSoyuz 2.1b) flew first on 27 December 2006 with theCoRoT satellite from theBaikonur Cosmodrome.
On 19 January 2005, theEuropean Space Agency (ESA) and theRoscosmos agreed to launch Soyuz ST rockets from theGuiana Space Centre.[7] The equatorial launch site allows the Soyuz to deliver 2.7 to 4.9 tonnes intoSun-synchronous orbit, depending on the third-stage engine used.[8] Construction of a new pad started in 2005 and was completed in April 2011. The pad used vertical loading common atFrench Guiana, unlike the horizontal loading used at theBaikonur Cosmodrome.[9] A simulated launch was conducted in early May 2011.[10] The first operational launch happened on 21 October 2011, bearing the first two satellites inGalileoglobal positioning system.
TheSoyuz-U andSoyuz-FG rockets were gradually replaced bySoyuz 2 from 2014 until 2019. Soyuz-U was retired in 2017,[11] while Soyuz-FG carriedastronaut crews to theISS until September 2019 (final flight,Soyuz MS-15, on 25 September 2019).
TheMolniya-M (1964–2010) was also derived from the Soyuz family.
The rocket is assembled horizontally in the Assembly and Testing Building. The assembled rocket is transported to the launch site in its horizontal state and then raised. This is different from the vertical assembly of, for example, theSaturn V, and is one of the features that makes Soyuz cheaper to prepare for launch. Assembling a horizontally positioned rocket is relatively simple as all modules are easily accessible. Assembling the rocket in vertical position would require a windproof high-rise hangar, which was not considered financially feasible at the time the rocket was designed, due to the failing economy of theSoviet Union.
The entire rocket is suspended in the launch system by the load-bearing mechanisms on the strap-on boosters where they are attached to the central core. The latter rests on the nose sections of the strap-on boosters. This scheme resembles flight conditions when the strap-on boosters push the central core forward. The concept of suspending the rocket was one of the novelties introduced with the R-7/Soyuz.
Since the launch pad has been eliminated, the bottom portion of the rocket is lowered. The launch system trusses bear the wind loads. Resistance to high wind is an important feature of the launch system, as theKazakhstan steppes, where the Baikonur launch site is located, are known forwindstorms.
The engines are ignited by electrically initiated pyrotechnic flares, mounted on birch poles, which are ignited at approximately T-20 seconds, a few seconds before fuel components (liquid oxygen and kerosene-based liquids) are introduced into the combustion chamber.[12] This sequence rarely fails due to its simplicity.[13] During launch, the support booms track the movement of the rocket. After the support boom heads emerge from the special support recess in the nose sections of the strapons, the support booms and trusses disconnect from the rocket air-frame, swiveling on the support axes and freeing the way for the rocket to lift off. During launch, the rocket and the launch facility form a single dynamic system.[clarification needed]
When the strap-on booster engines stop, the boosters fall away, providing non-impact separation. If the skies are clear, ground observers can see aKorolev cross formed by the falling boosters.
The Soyuzlaunch vehicle is used for various Russian uncrewed missions and is also marketed by Starsem for commercial satellite launches. Presently the following fairing types are used:
Progress is the cargo spacecraft for uncrewed missions to the ISS and previously toMir. The spacecraft uses a dedicated platform and fairing and can be launched with either Soyuz-U, Soyuz-FG or Soyuz-2.
A-type fairing is used for commercial launches.
S-type fairing is used for commercial launches by Starsem. The fairing has external diameter of 3.7 m and a length of 7.7 m. The Fregat upper stage is encapsulated in the fairing with the payload and a payload adapter/dispenser.[14] S-type fairing along with Fregat upper stage were used to launch the following spacecraft:Galaxy 14,GIOVE A,Mars Express,AMOS-2,Venus Express,Cluster.[15]
SL-type fairing is used for commercial launches by Starsem. The fairing has external diameter of 3.7 m and a length of 8.45 m. The Fregat upper stage is encapsulated in the fairing with the payload and a payload adapter/dispenser.[16] SL-type fairing along with Fregat upper stage were used to launch the following spacecraft:CoRoT.
ST-type fairing is used for commercial launches by Starsem. Its external diameter is 4.1 m and its length is 11.4 m. It can be used with the Soyuz-2 only, because older analog control system cannot cope with aerodynamic instability introduced by a fairing this large. This carbon-plastic fairing is based on the proven configuration used for Arianespace'sAriane 4 vehicles, with its length increased by approximately one additional meter.[17] The fairing has been developed and is being manufactured byTsSKB-Progress in accordance with the requirements of a customer (Starsem). This is the only fairing type offered by Starsem/Arianespace for launches from Kourou.[18]Progress M-UM is the only Progress Spacecraft that was launched while being enclosed in a ST fairing.
The first stage of Soyuz rockets consists of four identical conical liquid booster rockets strapped to the second stage core. These boosters are also calledBlok-B, V, G, and D.[a] Each engine has four main combustion chambers and twovernier thruster combustion chambers for attitude control. The engine is pump-fed by a hydrogen peroxide gas generator. Propellant tanks are pressurized using liquid nitrogen vaporization.[19]
Statistics (each of 4 boosters):
The Soyuz booster's second stage, also calledBlok-A, is a single, generally cylindrical stage with one motor at the base, activated alongside the first-stage boosters. Like each first-stage booster, it also has four combustion chambers but with four (instead of two) vernier thruster combustion chambers for attitude control. The engine is pump-fed by a hydrogen peroxide gas generator. Propellant tanks are pressurized using liquid nitrogen vaporization. The second stage tapers toward the bottom, allowing the four first-stage rockets to fit more closely together.
Statistics:
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There are two variant upper stages in use, theBlok-I (used on theSoyuz 2.1a) and theImproved Blok-I (used on theSoyuz 2.1b).[20]
Statistics:
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