In 1903 he published a rocket equation in a Russian aviation magazine. Called the Tsiolkovsky formula or Tsiolkovsky rocket equation, it described the relationships among rocket speed, the speed of the gas at exit, and the mass of the rocket and its propellant.
In 1929 he published his theory of multistage rockets, based on his knowledge of propulsion dynamics.
He was a big proponent of humanity moving out into the vastness of outer space: “Earth is the cradle of humanity, but one cannot remain in the cradle forever.”
Inspired in 1895 by the newly constructed Eiffel Tower in Paris, Tsiolkovsky was the first person to conceive of a space elevator.
During his lifetime he published approximately 90 works on space travel and related subjects, including designs for rockets with steering thrusters, multistage boosters, space stations, airlocks for exiting a spaceship, and closed-cycle biological systems to provide food and oxygen for space colonies.
11/16/66, Cape Kennedy: “Astronaut Ed Aldrin leans around to check his name on big sign detailing the exploits of the Gemini astronauts. Aldrin and James Lovell (R) returned 11/16 to spot from which their four-day-long Gemini-12 flight - the last in the series - began 11/11.”