Konstantin Eduardovich Tsiolkovsky was a Russian and Soviet rocket scientist who pioneered astronautics. Along with Hermann Oberth and Robert H. Goddard, he is one of the pioneers of space flight and the founding father of modern rocketry and astronautics. His works later inspired Wernher von Braun and leading Soviet rocket engineers Sergei Korolev and Valentin Glushko, who 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.

Astronautics is the practice of sending spacecraft beyond Earth's atmosphere into outer space. Spaceflight is one of its main applications and space science is its overarching field.