It established under a decree by the USSR Supreme Soviet of April 9, 1962 in honor of the world’s first space flight by a Soviet citizen MOSCOW, April 12. /TASS/. Russia celebrates April 12 as Cosmonautics Day, established under a decree by the USSR Supreme Soviet (the Soviet Union’s national legislature) of April 9, 1962 in honor of the world’s first space flight by a Soviet citizen. The idea of introducing this date to the calendar of the nation’s memorable events was proposed by the Soviet