Tsiolkovskij

Konstantin Eduardovich Tsiolkovsky, often transliterated Tsiolkovski, was a Russian and Soviet rocket scientist, physicist, and pioneer of astronautics. Born September 17, 1857, in Izhevskoye, Vyatka Governorate, Russian Empire, he spent much of his life in Kaluga, where he conducted theoretical research and published influential writings on spaceflight. A self-taught thinker and former schoolteacher, he pursued ideas about propulsion, rocketry, and space exploration through independent study and correspondence.

In 1903 he published The Exploration of Outer Space by Means of Rocket Devices, outlining the scientific basis for spaceflight and arguing for the use of liquid propellants, experimental rockets, and multistage designs. He derived what is now known as the Tsiolkovsky rocket equation, delta-v = v_e ln(M0/Mf), which relates a rocket’s exhaust velocity to the change in velocity achievable for a given mass ratio. He argued that space travel would require sustained propulsion, longer missions, and the construction of space infrastructure such as satellites and space stations. His theoretical work laid the groundwork for future rocket development and influenced later Soviet engineers.

Tsiolkovsky is regarded as the founding figure of astronautics. His legacy is reflected in the naming of lunar and planetary features and in ongoing studies of rocket theory in spaceflight. He died September 19, 1935, in Kaluga. His name is honored in astronomy and aerospace, including the lunar crater Tsiolkovskiy and the asteroid 1590 Tsiolkovskaya.