Konstantin Eduardovich Tsiolkovsky (September 17, [O.S. 5 September] 1857  – September 19, 1935) is a Russian and Soviet rocket scientist and pioneer of the astronautic theory.

Along with the French Robert Esnault-Pelterie, the German Hermann Oberth and the American Robert H. Goddard, he is considered to be one of the founding fathers of modern rocketry and astronautics.

His works later inspire leading Soviet rocket engineers such as Sergei Korolev and Valentin Glushko and contribute to the success of the Soviet space program.

Tsiolkovsky spends most of his life in a log house on the outskirts of Kaluga, about two hundred kilometers (one hundred and twenty miles) southwest of Moscow

A recluse by nature, his unusual habits make him seem bizarre to his fellow townsfolk.