SPACE.com -- Martian Life Could Have Evaded Detection by Viking Landers: "A chemical test used by the Mars Viking landers more than 30 years ago was not sensitive enough to detect signs of alien life even if it existed, a new study suggests.
Researchers analyzed soil from several harsh, Mars-like environments on Earth using the same gas spectrometry test employed by the Viking landers. But even in soil taken from areas teaming with microbial life, the tests failed to register any signs of organic material. Thus, 'the Martian surface could have several orders of magnitude more organics than the stated Viking detection limit,' the researchers write.
The finding, detailed in the current issue of the journal for the Proceedings of the National Academy of Sciences, could have implications for future missions aiming to dig up signs of extinct or existing life on the Red Planet.
The new study could also explain the detection of low levels of carbon dioxide in some Martian soil by the Viking landers, a puzzling finding which some scientists have used to argue for life on Mars."
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