The Bulgarian cosmonaut program refers to human spaceflight efforts by the People's Republic of Bulgaria. The idea of a Bulgarian manned space mission predated the launch of Sputnik 1, the first artificial satellite. An informal proposal for the Soviet Union to send a Bulgarian cosmonaut in space was issued in 1964, but it was not seriously considered by the Soviets. Official space cooperation began in 1966 with the establishment of the Interkosmos programme which allowed Communist Bloc countries to access Soviet space technology and assets.