Konstantin Tsiolkovsky (1857–1935) conducted experiments on air travel years before the first powered aircraft was flown by the Wright brothers in 1903. He constructed Russia’s first wind tunnel to study airflow acting on airplanes as they flew. In 1895 he introduced his ideas of space travel, and three years later he outlined many of the basic concepts of rocketry and space travel that scientists still use today. A true visionary, Tsiolkovsky was far ahead of any other scientist in this field. He wrote, for example, that humans could survive in space only if supplied with oxygen inside a sealed cabin. In 1903 he published an article titled “The Exploration of Cosmic Space by Means of Reaction Devices,” which detailed his ideas about rocket propulsion and the use of liquid fuels.