Who formulated the rocket equation that relates a rocket’s speed to its propellant?

Konstantin Tsiolkovsky formulated the rocket equation relating a rocket’s speed change to its propellant.

The equation is commonly called the Tsiolkovsky rocket equation. Tsiolkovsky published its mathematical basis in 1903, showing that a rocket’s change in velocity depends on exhaust velocity and the logarithm of the ratio between initial and final mass. This explained why rockets must carry large quantities of propellant and why staging is so useful.

Tsiolkovsky was a Russian schoolteacher and pioneering theorist who worked largely before practical liquid-fueled rockets existed. He also proposed multistage rockets, liquid propellants, and pressurized spacecraft concepts. His ideas became foundational for modern astronautics.

Robert Goddard, Hermann Oberth, and Wernher von Braun were important rocket pioneers, but they are not the names attached to this equation. The formula describes idealized motion and does not by itself account for atmospheric drag or gravity losses.