R-7 Semiorka (Семёрка) is very first the rocket to have placed a satellite orbits about it around the Earth. At the base, this rocket is formed on the model of a Russian intercontinental missile created in 1956. The rocket in itself, implemented by Sergueï Korolev, is actually completed in 1957. It was built in the Usine n° 1 of Samara.

Origin

The initial version of the launcher is of type “a stage and half”, made up of a central body and four accelerators. Each element has an engine quadrichambre RD-107/108. It is about a group of propulsion including/understanding only one system of pumps and four conduit/combustion chamber units whose unit push does not exceed that of a V-2 (250 K NR) whose Soviet, like American, had largely taken again technology. Vernier engines were added to it for the roll control (four on the central stage, two on each accelerator).

In the beginning, R-7 was conceived like intercontinental ballistic missile. Whereas the Americans had preferred to wait to lay out of H-bombs (much lighter than the bombs A) to develop of such weapons, Soviet, them, had developed this missile able to launch bombs has weighing 5 tons. Consequently, R-7 was twice larger than the Atlas American.

The missile consisted of a principal stage and four stages of acceleration (booster rockets). This solution, compared to two-stage traditional, made it possible to start all the engines on the bench of shooting, therefore to give up the shooting in the event of failure of the one of them, invaluable capacity for a rocket designed with beginning of the year 50, time when the reliability of the engines was very low. Moreover, the Atlas had been designed in same optics, having also all its engines ignited before takeoff.

Ironically, R-7 can be practically regarded as a failure in the role for which it was initially conceived, that of strategic missile. The missile did not remain in service a long time. Too much cumbersome to be launched of a silo, too long to once launch (because of the handling of the Oxygen liquid), oversize the H-bombs available it was quickly supplanted by storable missiles with Ergol S liquid. On the other hand, R-7 is for much the space launcher more successful of the History.

It is thus since the cosmodrome of Baïkonour, Kazakhstan, the October 4th 1957, that the first R7-Semiorka rocket is launched, with in its cap the satellite Sputnik 1. It was about a hardly modified version of the intercontinental missile, the satellite and a small cap replacing the enormous atomic warhead and its atmospheric shield.

Derived

Semiorka gave rise to number of derivative, each one named according to its first payload, which was used for almost all in space Russian, in particular for transport of men in the space (operation which requires a quasi-perfect reliability). All the Russian manned flights used rockets of this family.

• the Rocket Vostok: equipped with a small second stage (third for the Russians, which counts the booster rockets like first stage), for the first manned flights (Programme Vostok). An almost identical version known under the name Luna launched the first lunar probes. The most famous mission of this launcher is incontestably the flight of Youri Gagarine.

• the Rocket Voskhod: equipped with a second stages more massive with an engine quadrichambre, intended for the capsule of the same name, an increased version of Vostok for the first flights two-seater.

• the Rocket Soyuz: most famous, which launches the vessel Soyuz. Derived directly from Voskhod.

• the Rocket Molnya (Молния): A Soyuz with an additional stage, which launches the Molnya satellites, of the telecommunications satellites on a tilted elliptic orbit which enables them to ensure a similar service the geostationary satellites for the zones in high latitude. These rockets were also used for interplanetary and geostationary launchings.

All the stages use the combination of propellents liquid kerosene/oxygen. Since 1991, only the Soyuz and Molnya are still employed. The various versions listed below knew various improvements, in particular electronics progressed much. Nevertheless, the basic design of the launcher remained unchanged. Certain versions used in the place of the Kérosène a synthetic fuel, named Sintin , which increased the performances slightly.

The Soyuz version is known, because of its use in the inhabited programs (Salyut, ASTP Mir, ISS). So the name Soyuz tends to being applied to all the family. New commercial releases, with a third stage and intended for geostationary launchings (since Kourou) will be also called Soyuz, whereas, from their role, it apparante more in Molnya.

Always in activity after multiple improvements and in spite of the seniority of its initial creation, Semiorka remains one of the most reliable rockets of the world. More than 1600 specimens were launched.

Future trends

A new version, the 2-1a, or Soyuz 2, was launched successfully the November 8th 2004. It is this version which will leave the CSG, the Guianese Space center towards 2007. It will be able to receive the cap of the European rocket ARIANE 4, which should make commercially the launcher more competitive: this cap is more spacieuce that of the Soyuz current, it is also lighter, and the manufacturers of satellites know it well and offer platforms designed for it.

The most recent version was called Soyuz, because of the vessel of the same name that it transports, and this terms is very now often applied to the whole of the family.

See too

• Rocket Soyuz