Soyuz launch vehicle

The Soyuz launch vehicle (Western designation: A-2) is an expendable launch system manufactured by TsSKB-Progress in Samara, Russia. It is used as the launcher for the manned Soyuz spacecraft as part of the Soyuz program. It is now also used to launch unmanned Progress supply spacecraft to the International Space Station and for commercial launches marketed and operated by TsSKB-Progress and the Centre Spatial Guyanais in French Guiana. Soyuz-U rockets are fueled with kerosene, but the Soyuz-U2 rocket used a variant called Syntin.

History

The launcher was introduced in 1966, deriving from the Vostok launcher, which in turn was based on the 8K74 or R-7a intercontinental ballistic missile. It was initially a three-stage rocket with a Block I upper stage. Later a Molniya variant was produced by adding a fourth stage, allowing it to reach the highly elliptical molniya orbit. A later variant was the Soyuz-U. [cite web |url=http://www.samspace.ru/ENG/RN/ser_souz.htm |title="Soyuz" - series launch vehicles |publisher=Samara Space Centre]

The production of Soyuz launchers reached a peak of 60 per year in the early 1980s. It has become the world's most used space launcher, flying over 1700 times, far more than any other rocket. It is a very old basic design, but is notable for low cost and very high reliability, both of which appeal to commercial clients.

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 the Russian Space Agency and the Russian Ministry of Defence in 1993 and designated "Rus" as a Russification and modernisation 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 kg to geostationary transfer orbit. In April 1997, Starsem obtained a contract from the European Space Agency to launch two pairs of Cluster 2 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 September 22, 1999 and November 22, 1999. After successful test flights of Soyuz-Fregat on February 9, 2000 and March 20, 2000, the Cluster 2 satellites were launched on July 16, 2000 and August 9, 2000. Another Soyuz-Fregat launched the ESA's Mars Express probe from Baikonur in June 2003. Now the Soyuz-Fregat launcher is used by Starsem for commercial payloads. It is due to be replaced by the new launcher, now named Soyuz/ST (or Soyuz 2), which will have a new digital guidance system and a strongly modified third stage with a new engine. The first development version of Soyuz 2 called Soyuz-2-1a, which is already equipped with the digital guidance system, but is still propelled by an old third stage engine, started on November 4, 2004 from Plesetsk on a suborbital test flight, followed by an orbital flight on October 23, 2006 from Baikonur. The fully-modified launcher (version Soyuz-2-1b) flew first on December 27, 2006 with the COROT satellite from the Baikonur Cosmodrome.

A long string of successful Soyuz launches was broken on October 15, 2002 when the unmanned 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 injured. Another failure occurred on June 21, 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 Uvatski region of Tyumen (Siberia) [http://en.rian.ru/russia/20050621/40556511.html] . However, under this designation of Molniya-M launcher, the other 274 unmanned Soyuz launches have been successful.

Between February 1, 2003 and July 26, 2005 with the grounding of the US 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.

Soyuz (in the new version Soyuz/ST) is also planned to be brought into ESA service in 2008 under a Russo-European joint venture. A new launch pad is being built at the Guiana Space Centre in French Guiana.

Assembling the rocket

The rocket is assembled not vertically, but 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, the Saturn V - one of the features which makes Soyuz cheaper to prepare for launch.

Assembling a horizontally positioned rocket is relatively simple as all modules are easily accessible. Also, assembling the rocket in vertical position would require a windproof highrise hangar, which was not considered economically feasible at the time the rocket was designed.

Launch pad

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 missile is lowered. The launch system trusses bear the wind loads. Resistance to high wind is an important feature of the launch system, as the Kazakhstan steppes, where the Baikonur launch site is located, are known for windstorms.

Launch

During launch, the support booms track the movement of the rocket. After the support boom heads emerged from the special support recess in the nose sections of the strapons, the support booms and trusses disconnect from the rocket airframe, 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.

When the engines of strapon boosters stop, the boosters fall away, providing nonimpact separation. If the skies are clear, ground observers can see a Korolyov cross formed by the falling boosters.

Stages

First stage

The first stage of Soyuz rockets consists of four identical conical liquid booster rockets, strapped to the second stage core. Each booster has a single rocket motor with four combustion chambers, two vernier combustion chambers, and one set of turbopumps.

Statistics (each of 4 boosters)
* Gross mass: 44.5 t (98,100 lbm)
* Propellant: 39.2 t (86,400 lbm)
* Dry mass: 3,784 kg (8,342 lbm)
* Diameter: 2.68 m (8 ft 10 in)
* Length: 19.6 m (64 ft 4 in)
* Burn time: 118 s
* Engines:
** Soyuz and Soyuz-U models
*** RD-107
**** Thrust 813 kN (183 klb_f) at liftoff
**** Thrust 991 kN (223 klb_f) in vacuum
**** Specific impulse 245 s (2.40 kN·s/kg) at liftoff
**** Specific impulse 310 s (3.04 kN·s/kg) in vacuum
**** Chamber pressure 5.85 MPa (848 psi)
** Soyuz-ST models
*** RD-117 (11D511)
**** Thrust 838 kN (188 klb_f) at liftoff
**** Thrust 1021 kN (230 klb_f) in vacuum
**** Specific impulse 245 s (2.40 kN·s/kg) at liftoff (est)
**** Specific impulse 310 s (3.04 kN·s/kg) in vacuum (est)
**** Chamber pressure 5.85 MPa (848 psi)
** Soyuz-FG
*** RD-117A (14D22)
**** Thrust 775 kN (174 klb_f) at liftoff
**** Specific impulse 320.2 s (3.14 kN·s/kg) in vacuum

Second stage

The second stage of the Soyuz booster is a single, generally cylindrical stage with one motor at the base. Like each of the first-stage rockets, it also has four combustion chambers and one set of turbopumps, but four (instead of two) vernier combustion chambers. The second stage tapers toward the bottom to allow the four first stage rockets to fit more closely together.

* Gross mass: 105.4 t (232,400 lbm)
* Propellant: 95.4 t (210,000 lbm)
* Propellant (Soyuz-U2 with Syntin propellant): 96.4 t (212,000 lbm)
* Dry mass: 6,875 kg (15,160 lbm)
* Length: 28 m (91 ft 10 in)
* Diameter: 2.95 m (9 ft 8 in)
* Burn time: 290 s
* Engines:
** Soyuz and Soyuz-U models
*** RD-108
**** Thrust 779 kN (175 klb_f) at liftoff
**** Thrust 997 kN (224 klb_f) in vacuum
**** Specific impulse 264 s (2.59 kN·s/kg) at liftoff
**** Specific impulse 311 s (3.05 kN·s/kg) in vacuum
**** Chamber pressure 5.1 MPa (740 psi)
** Soyuz-U2 model with Syntin fuel
*** RD-108
**** Thrust 811 kN (182 klb_f) at liftoff
**** Thrust 1009 kN (227 klb_f) in vacuum
**** Specific impulse 264 s (2.59 kN·s/kg) at liftoff
**** Specific impulse 311 s (3.05 kN·s/kg) in vacuum
**** Chamber pressure 5.1 MPa (740 psi)
** Soyuz-ST models
*** RD-118 (11D512)
**** Thrust 792 kN (178 klb_f) at liftoff
**** Thrust 990 kN (222 klb_f) in vacuum
**** Specific impulse 264 s (2.59 kN·s/kg) at liftoff (est)
**** Specific impulse 311 s (3.05 kN·s/kg) in vacuum (est)
**** Chamber pressure 5.85 MPa (848 psi)

Third stage

There are two variant upper stages in use, the Block I and Improved Block-I (used in Soyuz-2-1b).
* Gross mass: 25.2 t (55,600 lbm)
* Propellant: 21.4-22.9 t (47,200–50,500 lbm)
* Dry mass: 2355 kg (5190 lbm)
* Length: 6.7 m (22 ft 0 in)
* Diameter: 2.66 m (8 ft 9 in)
* Burn time: 240 s
* Engine:
** Block I
*** RD-0110
*** Thrust 298 kN (67.0 klb_f)
*** Specific impulse 330 s (3.24 kN·s/kg)
*** Chamber pressure 6.8 MPa (986 psi)
** Improved Block I
*** RD-0124 (11D451)
*** Thrust 294 kN (66 klb_f)
*** Specific impulse 359 s (3.52 kN·s/kg)
*** Chamber pressure 16.2 MPa (2350 psi)

References

* "International Reference Guide to Space Launch Systems, Third Edition", Iaskowitz, Hopkins, and Hopkins ed., 1999, Reston, Virginia, AIAA Publications. ISBN 1-56347-353-4

External links

* [http://internetelite.ru/cosmopark/r7/r7.htm R-7 missile family page]
* [http://www.starsem.com Starsem]
* [http://www.starsem.com/soyuz/log.htm Soyuz launch log at Starsem]
* [http://www.orbireport.com/Launchers/Soyuz_U-Fregat/ Soyuz U/Fregat]
* [http://www.esa.int/SPECIALS/Delta_Mission/SEM8XK57ESD_0.html Soyuz launch vehicle: The most reliable means of space travel]
* [http://home.comcast.net/~rusaerog/boosters/R-7.html|Soyuz Booster Family]