コンスタンチン・ツィオルコフスキー
The first realistic proposal of spaceflight goes back to Konstantin Tsiolkovsky. His most famous work, "" ("Issledovanie mirovikh prostranstv reaktivnimi priborami", or "The Exploration of Cosmic Space by Means of Reaction Devices"), was published in 1903, but this theoretical work was not widely influential outside Russia.