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What did the Viking landersā life-detection experiments on Mars find?
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extraterrestrial life
An illustration of the Earth-size planet TOI 700e orbiting within the habitable zone of its star. The habitable zone is the area around a star where liquid water, and thus possibly life, can survive on a planet's surface. Its Earth-size sibling, TOI 700d, can be seen in the distance.
The Viking landers, which touched down on Mars in 1976, carried a suite of sophisticated experiments specifically designed to detect metabolism and organic molecules in the Martian soil.12
Ultimately, these onboard life-detection experiments provided no convincing signs of biological activity on the planet's surface. The negative results from these tests led to a period of considerable pessimism regarding the potential for life on Mars that persisted throughout the 1980s. While the landers successfully returned detailed data concerning Martian geology, meteorology, and atmospheric chemistry, they failed to find unequivocal evidence of life.132