The Vostok SL-1 (Semyorka) booster was based on the R-7 Intercontinental Ballistic Missile (ICBM), the world's first ICBM. It holds the distinction of launching the world's first artificial satellite the SPUTNIK - 1 and to the entire globe a very important piece of sophisticated machinery. A total of 12 launches were undertaken, of which 4 were devoted to satellites. On 11 April 1961, Yuri Alekseyevich Gagarin became the first human in space launched on Vostok-1. After circling the earth, Gagarin ejected and re-entred earth's atmosphere and descended under his own parachute, as planned in Engels Smelovka, Saratov.