Vostok (translated as "East") was a family of rockets derived from the Soviet R-7 Semyorka ICBM and was designed for the human spaceflight programme. This family of rockets launched the first artificial satellite (Sputnik 1) and the first crewed spacecraft (Vostok) in human history. It was a subset of the R-7 family of rockets.
On March 18, 1980, a Vostok-2M rocket exploded on its launch pad at Plesetsk during a fueling operation, killing 48 people. An investigation into a similar – but avoided – accident revealed that the substitution of lead-based for tin-based solder in hydrogen peroxide filters allowed the breakdown of the H2O2, thus causing the resultant explosion.
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