NASA's Curiosity rover is a gigantic mobile laboratory. During the last year, it has roved over the Martian surface exploring a small section of Gale crater while making huge scientific discoveries.
The rover was built as a data-generating machine. You put rocks, air, and samples in and you get science out. Specifically, Curiosity is searching for signs of ancient habitability and seeking to answer an important question: Could Mars have ever had living organisms crawling over its surface?
Curiosity's science team includes geologists, chemists, physicists, astrobiologists, and countless other researchers. Using the probe's state-of-the-art equipment, they have drilled into Martian rocks, fired lasers and X-rays, baked powdered soil for analysis, and sniffed the atmosphere. Many of these activities had never been done on the Red Planet, or any planet beyond Earth, before. The data received from Curiosity has bolstered the idea that the planet once had water flowing over its surface and was a place where life could have conceivably thrived. It will take many more months and years of exploring to completely tease out all the details but the rover has already exceeded the expectations of its original designers.
When Curiosity landed on Mars in August 2012, no one yet knew what it would find. Here, we take a look at the last year of scientific explorations, how the rover has expanded our knowledge about Mars, and what the future may hold.
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Ancient Mars Was Habitable
The most important finding that Curiosity has made so far is that the ancient environment of Mars was habitable. This was literally the result that the rover was built for. After drilling into a rock and analyzing a sample of its interior, Curiosity found that roughly 20 to 30 percent of its composition was smectite minerals.
Smectites are particular minerals that would have formed in the presence of neutral, non-salty water. This indicates a body of water that was so fresh, you basically could have drunk it, said project scientist John Grotzinger during the announcement in March. This contrasts with the findings of previous Mars rovers, which found jarosite minerals that could have only formed in highly acidic or salty water.
Curiosity also found that the interior of Mars rocks contained sulfur minerals from which microbes could have derived energy. While the discoveries don't say for sure whether or not life existed billions of years ago on Mars, they provide very tantalizing evidence. Hopefully, further data will provide even better confirmation of Mars' ancient habitability.
Image: Grey-green unoxidized powder from the interior of a Martian rock that helped determine the composition of the planet billions of years ago. NASA/JPL-Caltech/MSSS