Commemorating Viking Space Missions - United States Unmanned Space Accomplishments Block of Stamps

OFFICIAL FIRST DAY OF ISSUE READ ArtCraft HAMPION JUL 20 1978 23669 Commemorating Viking Space Missions UNITED STATES UNMANNED SPACE ACCOMPLISHMENTS Viking missions to Mars Viking missions to Mars Expanding human knowledge USA15c FIRST DAY OF ISSUEC Viking missions to Mars Expanding human knowledge USA 15c CCO Viking missions to Mars Expanding human knowledge USA15c Expanding human knowledge USA15c