Nikolai Kibalchich

Nikolai Kibalchich was a Russian revolutionary and self-taught engineer who, while imprisoned and awaiting execution in Saint Petersburg's Peter and Paul Fortress in March 1881 for his role as chief bomb-maker in the assassination of Tsar Alexander II, sketched and wrote a detailed technical proposal for a piloted, rocket-propelled flying machine using a solid-fuel gunpowder engine with variable, pulsed thrust to control ascent. Written in the seventeen days between his death sentence and his hanging on April 3, 1881, the document is regarded by space historians as the earliest known serious technical proposal for human rocket flight, predating the more famous theoretical work of Konstantin Tsiolkovsky by more than a decade, though it was suppressed by Tsarist authorities and not published until 1918, after the Russian Revolution. Kibalchich stated in the document's own preface that he believed in the feasibility of his idea and found comfort in it even as he faced his own execution; a lunar crater is named in his honor.