NASA launched the Viking 1 planetary probe toward Mars.
The Viking 1 was the first successful Mars lander in history.
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The mapping of Mars' surface began.
NASA lost contact with the Mars Observer spacecraft.
The US Mariner 9 was launched – it went on to become the first satellite to orbit Mars.
The Perseverance rover successfully landed on Mars.
One of Mars' moons, 'Deimos,' was discovered by an American astronomer, Asaph Hall.
