Nikita Sergeyevich Khrushchev (April 15 [O.S. April 3] 1894 – September 11, 1971) was a Russian politician who led the Soviet Union during part of the Cold War. He served as First Secretary of the Communist Party of the Soviet Union from 1953 to 1964, and as Chairman of the Council of Ministers, or Premier, from 1958 to 1964. Khrushchev was responsible for the de-Stalinization of the Soviet Union, for backing the progress of the early Soviet space program, and for several relatively liberal reforms in areas of domestic policy. Khrushchev's party colleagues removed him from power in 1964, replacing him with Leonid Brezhnev as First Secretary and Alexei Kosygin as Premier.