section_path: History
section_name: History
paragraph_text: History
  
  The first theoretical proposal of space travel using rockets was published by Scottish astronomer and mathematician William Leitch, in an 1861 essay "A Journey Through Space". More well-known (though not widely outside Russia) is Konstantin Tsiolkovsky 's work, " Исследование мировых пространств реактивными приборами " (The Exploration of Cosmic Space by Means of Reaction Devices), published in 1903.
  
  Spaceflight became an engineering possibility with the work of Robert H. Goddard 's publication in 1919 of his paper A Method of Reaching Extreme Altitudes. His application of the de Laval nozzle to liquid-fuel rockets improved efficiency enough for interplanetary travel to become possible. He also proved in the laboratory that rockets would work in the vacuum of space; nonetheless, his work was not taken seriously by the public. His attempt to secure an Army contract for a rocket-propelled weapon in the first World War was defeated by the November 11, 1918 armistice with Germany. Working with private financial support, he was the first to launch a liquid-fueled rocket on March 16, 1926. Goddard's papers were highly influential internationally in his field.
  
  In the course of World War II, the first guided rockets, the V-2, were developed and employed as weapons by Nazi Germany. At a test flight in June 1944 one such rocket reached space at an altitude of 189 kilometers (102 nautical miles), becoming the first man-made object to do so. At the end of World War II, most of the V-2 rocket team including its head, Wernher von Braun, surrendered to the United States, and were expatriated to work on American missiles at what became the Army Ballistic Missile Agency, producing missiles such as Juno I and Atlas.
  
  The Soviet Union under Joseph Stalin developed intercontinental ballistic missiles to carry nuclear weapons as a counter measure to United States bomber planes. The Tsiolkovsky-influenced Sergey Korolev became the chief rocket designer, and derivatives of his R-7 Semyorka missiles were used to launch the world's first artificial Earth satellite, Sputnik 1, on October 4, 1957, and later the first human to orbit the Earth, Yuri Gagarin in Vostok 1, on April 12, 1961.
  
  The first US satellite was Explorer 1, launched on February 1, 1958, and the first American in orbit became John Glenn in Friendship 7 on February 20, 1962. As director of the Marshall Space Flight Center, Von Braun oversaw development of a larger class of rocket called Saturn, which allowed the US to send the first two humans, Neil Armstrong and Buzz Aldrin, to the Moon and back on Apollo 11 in July 1969. At the same time, the Soviet Union secretly tried but failed to develop the N1 rocket, meant to give them the capability to land humans on the Moon.
  
  Spaceflight has been widely employed by numerous government and commercial entities for placing satellites into orbit around Earth for a broad range of purposes. Certain government agencies have also sent uncrewed spacecraft exploring space beyond the Moon and developed continuous crewed human presence in space with a series of space stations, from the Salyut program to the International Space Station.