Following Stalin's death in 1953, a period known as de-Stalinization and the Khrushchev Thaw occurred under the leadership of Nikita Khrushchev. The country developed rapidly, as millions of peasants were moved into industrialized cities. The USSR took an early lead in the Space Race with the first ever satellite and the first human spaceflight and the first probe to land on another planet, Venus. In the 1970s, there was a brief "détente" of relations with the United States, but tensions resumed when the Soviet Union deployed troops in Afghanistan in 1979. The war drained economic resources and was matched by an escalation of American military aid to Mujahideen fighters.