The Russian schoolteacher Konstantin E. Tsiolkovsky was the first to state the correct theory of rocket power.
Image: NASA.

In 1935 on this date, Konstantin E. Tsiolkovskiy died. Tskiolkovskiy was the chief Soviet theorist of spaceflight, developed mathematics of rocketry and space travel, and identified basic rocket and spacecraft designs. A concise biography of Tsiolkovskiy may be found at Encyclopedia Britannica’s website here.