Curiosity is the latest and by far the largest of four NASA rovers. In 1997 Sojourner, the smallest and simplest, proved that Mars roving was possible.    Spirit and Opportunity analyzed rocks, confirming evidence from orbiters that large amounts of water had once been present on Mars. (Opportunity is still roving after nine years and 22 miles.)   Curiosity can drill into rocks and scoop the powder into an onboard chemical lab. It’s looking not just for water but also for ancient environments where microbes could have lived. “We are not searching for life itself; that would take instruments even more advanced than Curiosity’s. Its job is to help us figure out where a future mission should look for life”, says John Grotzinger, Caltech geologist and chief scientist for the Curiosity mission.                   

 _{(In: Field trip on Mars, by John Grotzinger.  National Geographic, vol. 224 . no. 1, July 2013. Adaptado)}

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