R-7 (rocket family)

The R-7 family of rockets (Р-7) is a series of rockets, derived from the Soviet R-7 Semyorka, the world's first ICBM. More R-7 rockets have been launched than any other family of large rockets.

History
The R-7 turned out to be impractical as a ballistic missile, but found a long application in the Soviet and then Russian space programmes. The R-7 family consists of both missiles, and orbital carrier rockets. Derivatives include the Vostok, Voskhod and Soyuz rockets, which have been used for all Soviet, and later Russian manned spaceflights. The type has a unique configuration where four break-away liquid-fueled engines surround a central core. The core acts as a "second stage" in effect after the other four engines are jettisoned.

Later modifications were standardised around the Soyuz design. The Soyuz-U, Soyuz-FG and Soyuz-2 are currently in use. The Soyuz-U and FG are to be retired over the next few years, in favour of the Soyuz-2. R-7 rockets are launched from the Baikonur Cosmodrome and the Plesetsk Cosmodrome. A third launch site, at the Guiana Space Centre in French Guiana, was to open in 2009 but the first Soyuz launch has been postponed several times. The first launch from Guiana Space centre took place on October 21, 2011. Guiana will be used primarily for commercial launches to geosynchronous orbit, taking advantage of the launch site's proximity to the equator.

As of 2013, every manned Russian or Soviet spaceflight has been launched by an R-7 family rocket.



Korolev cross
The Korolev cross is a visual effect observed in the smoke plumes of the R-7 series rockets during separation of the four liquid-fueled booster rockets attached to the core stage. As the boosters fall away from the rocket, they pitch over symmetrically due to aerodynamic forces acting on them, forming a cross shape behind the rocket. The effect is named after Sergey Korolev, who designed the R-7. When the rocket is launched into clear skies, the effect can be seen from the ground at the launch site.