Soyuz

Vehicle Configurations

Vehicle Components

The Soyuz launcher is the latest in a remarkable series of rockets based on Korolev's original R-7 (Semyorka). R-7 was the first intercontinental ballistic missile, able to hurl heavy thermonuclear warheads to U.S. cities. R-7-based launchers launched the first earth orbiting satellite, boosted the first man into space, and sent the first spacecraft to the Moon, to Venus, and into solar orbit.

Taken together, all R-7 types have logged more than 1,700 launches since 1956, far more than any other space launcher. Soyuz, the current three-stage version, has flown more than 860 times since its first launch in 1965. The Soyuz rocket is best known for boosting manned Soyuz and unmanned Progress cargo spacecraft into low earth orbit from the Baikonur Cosmodrome in Kazakhstan, but many more have launched reconnaisance and scientific satellites from both Baikonur and from Russia's once secret Plestesk Northern Cosmodrome. Soyuz can put more than 7 metric tons into low earth orbit (LEO).

Molniya, a four stage R-7 variant most often used to boost communication satellites into highly elliptical 12-hour orbits, has flown more than 300 times from Plestesk since 1960. Molniya can boost about 2 tons into the high-inclination 12-hour "Molniya" orbit.

During the late 1970s and early 1980s, nearly 60 Soyuz/Molniya rockets were built at the Samara Space Center plant (now called TsSKB-Progress) in Samara, Russia each year.  Even as Semyorka launch rates exceeded one per week, the rocket's mission reliability improved to better than 0.97, among the best in the world.   

In 1996, Starsem, a Russian-European joint venture, was established to market the Soyuz launcher for commercial use. Starsem, headquartered in Paris, France, and owned by EADS (35%), Arianespace (15%), the Russian Aeronautics and Space Agency, Rosaviacosmos (25%), and the Samara Space Center, TsSKB-Progress (25%).

Starsem funded development of two new restartable fourth stages, Ikar and Fregat, and bankrolled improvements to the Soyuz launcher. The base Soyuz-U was initally upgraded to become Soyuz-FG with more powerful booster and core stage engines. Meanwhile, development of the Soyuz-ST series (initiated with Soyuz-2-1a and Soyuz-2-1b upgrades), with a larger payload fairing, upgraded digital control system, and more efficient upper stage engine, was begun.

Ikar, used for six Globalstar constellation launches in 1999, was supplanted by the more powerful Fregat in 2000. With Fregat, the Soyuz launch vehicle can perform commercial missions to geosynchronous transfer orbit (GTO) or can boost civilian reseach spacecraft into deep space. With continued use by the Russian government, for International Space Station (ISS) missions, and for Starsem commercial missions (which include European Space Agency flights), Soyuz/Molniya continues to be the world's busiest space launcher, flying 10-15 times per year.

The basic three stage Soyuz uses the time-tested Semyorka booster, consisting of a core stage and four strap-on boosters.  Each booster is powered by an RD-107 kerosene/liquid oxygen (LOX) engine (RD-107A for Soyuz-FG and Soyuz-ST), composed of four fixed thrust chambers and two gimballed verniers.  An RD-108 (or RD-108A), basically an RD-107 with four, instead of two, verniers, powers the core stage.  At liftoff, all 32 thrust chambers ignite to produce nearly 423 tons of thrust. 

Each booster carries its own LOX in a forward, tapered tank and kerosene in a cylindrical, aft tank.  The core stage aft kerosene tank is nestled within the boosters at liftoff, while the larger diameter core LOX tank is positioned above the booster attach points.  The boosters (first stage) shut down and fall away after 118 seconds.  The core (second) stage continues its burn, shutting down 286 seconds (Soyuz-U) or 290 seconds (Soyuz-FG and Soyuz-ST) after ignition.   

The Soyuz third stage, powered by a single RD-0110 LOX/kerosene engine composed of four, fixed main thrust chambers and four gimballed verniers, ignites while attached to the first stage.  A lattice structure allows exhaust gases to escape during the start sequence.  After staging, a three-part aerodynamic skirt, below the LOX tank at the base of the third stage, is jettisoned. On a three-stage mission, RD-0110 provides 30.4 tons thrust for about 240 seconds to inject itself and its payload into orbit. On a four-stage flight, two options are available. The third stage can either propel Fregat into orbit or Fregat can perform an initial burn to reach orbit, leaving the third stage to fall back to earth on a suborbital trajectory.

Soyuz-2-1a first flew on a successful suborbital test flight from Plestesk in November 2004.  Its first Baikonur launch for Starsem was planned for mid-2006.  The upgraded design features a new digital control computer and inertial measurement unit.  The new control systems allow Soyuz to perform in-flight roll and dog-leg maneuvers for the first time.  Previously, R-7 launchers were rotated on the pad to the proper flight azimuth prior to launch.  Soyuz-2-1a can also be fitted with the new 4.1 meter diameter "ST" payload fairing.

A more powerful RD-0124 staged-combustion engine will replace RD-0110 on the Soyuz-2-1b variant, which is expected to debut in late 2006.   RD-0124 will produce about the same thrust as RD-0110, but at 34 seconds higher specific impulse so that the engine will be able to burn longer using the same amount of propellant.  With the new engine, Soyuz 2-1b will be able to lift up to 8.5 tonnes to low earth orbit from Baikonur and more than 9 tonnes from Kourou.  With a Fregat upper stage, the upgraded launcher will be able to boost 3 tonnes to geosynchronous transfer orbit from Kourou, allowing it to carry as much mass as some Ariane 4 versions.
    

Fregat is powered by the S5.92 storable propellant engine, which burns unsymmetrical dimethyl hydrazine (UDMH) fuel and nitrogen tetroxide (N2O4) oxidizer to produce 2 tons of thrust. The engine is capable of up to 20 restarts during a mission. Fregat can provide more than 880 seconds of burn time.

The Soyuz launch vehicle and its payload are integrated horizontally in a hanger. The rocket is moved by rail and erected on the pad only two days before launch.

Currently Starsem's Soyuz/Fregat only flies from Baikonur Area 31/Pad 6, but work has begun on a new launch site at Kourou in South America. Soyuz-2-1a and 2-1b will initally fly from Kourou. 

Soyuz/Molniya Russian government missions continue from Baikonur Area 1/Pad 5 and from Plestesk Area 16/Pad 2 and Area 43/Pads 3 and 4.

Vehicle Configurations

Vehicle Components

Vehicle Components Cont'd

Soyuz-U Launch Sequence (Typical)

References

Soyuz User's Manual, Starsem, April 2001
http://www.npoenergomash.ru/eng/engines/rd107/

 Last Update:  May 5, 2011