Soviet space-themed , 1950s-1960s ()
Soviet space-themed , 1950s-1960s ()
Soviet space-themed QSL-cards from the 1970s ()
Soviet QSL-cards from 1970s ()
Soviet (radio contact confirmation), 1961 ()
Interestingly, this sort of card was free to mail in the USSR.
Soviet , 1936—1949 ()