Originally Answered: Is life on Mars feasible?
For this reason we have to take care to sterilize our spacecraft heading for Mars.
We don't have any confirmed habitats on Mars, and don't have any detection of life there. But that's mainly because we haven't looked. Curiosity and Opportunity couldn't detect life even if there was life everywhere in the sand at low concentrations (as Levin suggests there is, from the Viking results).
And Mars is a vast varied landscape, same land area as the Earth (if you ignore the oceans). Many habitats suggested there. And life could be in all of them, or none of them, or just some of them.
And the life in such harsh conditions would be likely to survive below the surface (just mms maybe but invisible from orbit) or below the surface of rocks, or buried deep in ice sheets, a few tens of centimeter below the surface. And in very low concentrations. It's no surprise that we haven't spotted ityet.
Until we know for sure if these habitats exist or not, and whether Earth life can survive in them, and whether there is native life in them - we surely have to be careful not to send humans anywhere near the surface of Mars. Or the chances are that it will be a big anticlimax - we will just find whatever life we bring there in our spaceships.
About the Author
Robert Walker
Writer of articles on Mars and Space issues - Software Developer of Tune Smithy, Bounce Metronome etc.Studied at Wolfson College, Oxford
Lives in Isle of Mull
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