Konstantin Eduardovich Tsiolkovsky (Russian: Константин Эдуардович Циолковский, IPA: [kənstɐnʲˈtʲin ɪdʊˈardəvʲɪtɕ tsɨɐlˈkofskʲɪj] ; 17 September [O.S. 5 September] 1857 – 19 September 1935) was a Russian and Soviet rocket scientist and pioneer of the astronautic theory. Along with the French Robert Esnault-Pelterie, the Transylvanian 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 inspired leading Soviet rocket engineers such as Sergei Korolev and Valentin Glushko and contributed to the success of the Soviet space program.
Tsiolkovsky spent most of his life in a log house on the outskirts of Kaluga, about 200 km (120 mi) southwest of Moscow. A recluse by nature, his unusual habits made him seem bizarre to his fellow townsfolk.