This 1978 stamp celebrates the 2nd anniversary of the first mission to land a spacecraft on
another planet. This mission to Mars launched on August 20, 1975. The Viking 1 lander
touched down on the western slope of Chryse Planitia (the Plains of Gold), while the Viking 2
lander settled down at Utopia Planitia. The landing happened on July 20, 1976. Although
planned to only function for ninety days, the Viking 1 lander continued to operate until July 25,
This mission produced much scientific data and amazing photographs about the Martian
atmosphere and the planet of Mars.
Issue Date: July 20, 1978