This Day in History: July 20
July 20, 1976
First Robot Viking I Lands on Mars
Viking I landed on Mars to explore the surface of the Red Planet. The first robots on Mars, Viking I and its successor gave scientists their first information about the planet's surface, including information they hoped would allow people to walk there. Although the Viking probes found no evidence of life on Mars, they returned detailed pictures of the planet and information about the soil's composition.