During the late 1950s the Soviet Union and the United States confined their Cold War competition for dominance in space to unmanned satellites. The Soviets successfully launched the first satellite, Sputnik 1, on October 4, 1957, and the U.S. quickly answered the challenge with their own Explorer 1. President Dwight D. Eisenhower, impressed by the success of Explorer 1 and determined that this new technology should remain outside the control of the military, sponsored the creation of the National Aeronautics and Space Administration (NASA). However, he remained unconvinced that humans belonged in space and, despite the arguments of such eminent scientists as Wernher von Braun to the contrary, believed that unmanned space flight should be NASA's primary pursuit.

_{Yuri Gagarin} Unlike the United States, the Soviet Union actively pursued manned flight. In 1959 and 1960 a design team headed by Sergei Kolorev constructed several prototypes of the first manned spacecraft, Vostok ("East...