 The decision by the Ministry of Supply under Attlee's government to concentrate on research into nuclear power generation and sub-sonic passenger jet aircraft over supersonic atmospheric flight and spaceflight delayed the introduction of both of the latter (although only by a year in the case of supersonic flight, as the data from the Miles M.52 was handed to Bell Aircraft.Over a decade after the "Megaroc" proposal, true orbital space flight, both uncrewed and crewed, was developed by the Soviet Union and the United States during the Cold War, in a competition dubbed the "Space Race".The race began in 1957, when both the US and the USSR made statements announcing they planned to launch artificial satellites during the 18 month long International Geophysical Year of July 1957 to December 1958.