On July 20, 1976, the Viking 1 lander, an unmanned U.S. planetary probe, became the first spacecraft to successfully land on the surface of Mars. On This Day, July 20: Viking 1 is first spacecraft to land on Mars
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On July 20, 1976, the Viking 1 lander, an unmanned U.S. planetary probe, became the first spacecraft to successfully land on the surface of Mars. 
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