Curiosity – searching in vain?

Published in Chemistry World, 2 Aug 2012

On 6 August, if all goes to plan, NASA’s Curiosity probe will touch down on a rocky crater close to the Martian equator. Its main mission objective is to look for signs of habitability – evidence that there is, or has been at some point in the past, conditions favourable to life. Yet amid the anxiety over the forthcoming landing, some scientists are wondering: if there are signs of habitability, will Curiosity be able to detect them?

The search for life on Mars has a long history, dating at least back to 1976, when NASA’s Viking landers explored the Red Planet. Those landers mixed into the Martian soil a radioactive nutrient solution and subsequently detected the emission of radioactive gas – a result that suggested the presence of microbial activity. Confusingly, however, another experiment on the landers found no evidence of organic compounds – and, by extension, no microbes. […]

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