He was born in Izhevskoye (now in Spassky District, Ryazan Oblast), in the Russian Empire, to a middle-class family. His father, Edward Tsiolkovsky (in Polish: Ciołkowski), was Polish; his mother, Maria Yumasheva, was an educated Russian woman. At the age of 10, Konstantin caught a serious illness and became hard of hearing. He was not accepted at elementary schools because of his hearing problem, so he was self-taught.
Tsiolkovsky theorized many aspects of space travel and rocket propulsion. He is considered the father of human spaceflight and the first man to conceive the space elevator, becoming inspired in 1895 by the newly-constructed Eiffel Tower in Paris.
He was also an adherent of philosopher Nikolai Fyodorov, and believed that colonizing space would lead to the perfection of the human race, with immortality and a carefree existence.
Nearly deaf, he worked as a high school mathematics teacher until retiring in 1920. Only from the mid 1920s onwards the importance of his work was acknowledged by others, and Tsiolkovsky was honoured for it. He died on 19 September 1935 in Kaluga and was buried in state.
In the late 19th and early 20th century, Tsiolkovsky delved into theories of heavier-than-air flying machines, independently working through many of the same calculations that the Wright brothers were doing at the same time. However, he never built any practical models, and his interest shifted to more ambitious topics. Tsiolkovsky’s ideas were little known outside Imperial Russia, and the field lagged until German and other scientists independently made the same calculations decades later.
In 1923, German Hermann Oberth published his thesis "By Rocket into Planetary Space", which triggered wide-scaled interest and scientific research on the topic of space flight. It also reminded Friedrich Zander about once having read an article on the subject. He contacted the author and became active in promoting Tsiolkovsky’s work, and developing it further. In 1924 Zander established the first astronautics society in the Soviet Union, the Society for Studies of Interplanetary Travel, and later researched and built liquid-fuelled rockets named OR-1 (1930) and OR-2 (1933).
Only late in his lifetime Tsiolkovsky was honoured for his pioneering work. On 23 August 1924 he was elected as a first professor of the Military Aerial Academy named after N. E. Zhukovsky (Russian: Военно-воздушная академия им. Н. Е. Жуковского).
His most important work, published in 1903, was "Исследование мировых пространств реактивными приборами" (The Exploration of Cosmic Space by Means of Reaction Devices), arguably the first academic treatise on rocketry. Tsiolkovsky calculated that the horizontal speed required for a minimal orbit around the Earth is 8 km (5 miles)/second and that this could be achieved by means of a multistage rocket fueled by liquid oxygen and liquid hydrogen.
During his lifetime he published over 500 works on space travel and related subjects, including science fiction novels. Among his works are designs for rockets with steering thrusters, multi-stage boosters, space stations, airlocks for exiting a spaceship into the vacuum of space, and closed cycle biological systems to provide food and oxygen for space colonies.
Tsiolkovsky had been developing the idea of the air cushion since 1921, publishing fundamental paper on it in 1927, entitled Сопротивление воздуха и скорый поезд ("Air Resistance and the Express Train"). In 1929 Tsiolkovsky proposed the construction of multistage rockets in his book Космические ракетные поезда (Space Rocket Trains).
His and Oberth’s work influenced later rocketeers throughout Europe, like Wernher von Braun, and was also studied by the Americans in the 1950s and 1960s as they sought to understand the Soviet Union‘s successes in space flight.
- "The Earth is the cradle of humanity, but mankind cannot stay in the cradle forever."
- "Men are weak now, and yet they transform the Earth’s surface. In millions of years their might will increase to the extent that they will change the surface of the Earth, its oceans, the atmosphere and themselves. They will control the climate and the solar system just as they control the Earth. They will travel beyond the limits of our planetary system; they will reach other Suns and use their fresh energy instead of the energy of their dying luminary."
- "Man must at all costs overcome the Earth’s gravity and have, in reserve, the space at least of the Solar System."
- The basic equation for rocket propulsion, the Tsiolkovsky rocket equation, is named after him.
- The State Museum of the History of Cosmonautics in Kaluga now bears his name.
- Tsiolkovskiy crater on the far side of the moon was named after him, while asteroid 1590 Tsiolkovskaja was named after his wife.
- A fictional ship, the К. Э. Циолковский (K. E. Tsiolkovsky), was named after him for the television series Star Trek: The Next Generation. The episode it appeared in was entitled "The Naked Now". A copy of the dedication plaque of that vessel, with a rough rendering of Tsiolkovsky’s Cyrillic name, was seen in the ship’s set dressing. (the artist mistakenly used "З" instead of "Э" for the middle initial, and "п" instead of "л" in the last name). See also its entry at Memory Alpha.
- A space station is named Tsiolkovsky 1 in William Gibson‘s short story Hinterlands.