On ongoing theme. Any stamp that commemorates space exploration. This does not include sci-fi related stamps.
colnect.com
Letter Rate 5¢ Package Rate 5¢ Postcard Rate 4¢ Effective 1/7/1963 American President Lyndon B Johnson (11/22/1963-1/20/1969) British Prime Minister Harold Wilson (10/16/1964-6/19/1970) German President Heinrich Lübke (9/13/1959-6/30/1969)