It's been seven years since NASA's Curiosity rover touched down on Mars, but the robot geologist is still tackling big questions about Red Planet rocks.
Most recently, Curiosity has been focused on a region scientists call the "clay-bearing unit," which is located on the side of Mount Sharp, a peak nestled inside of Gale Crater. As the name suggests, the rock here is full of clay, which forms in wet areas. That's why scientists are so intrigued by the rock: They believe Curiosity's analysis will help them understand the environment here billions of years ago, when Mars was wet and perhaps more habitable.
"This area is one of the reasons we came to Gale Crater," Kristen Bennett, a planetary scientist at the U.S. Geological Survey and one of the co-leads for Curiosity's clay-unit campaign, said in a statement. "We've been studying orbiter images of this area for 10 years, and we're finally able to take a look up close."
Since touching down on Mars in August 2012, Curiosity has traveled 13 miles (21 kilometers). The leisurely pace has let the robot drill 22 samples of the Red Planet, among plenty of other science tasks.
But Curiosity's current location is particularly intriguing to scientists because of all that clay. "We're seeing an evolution in the ancient lake environment recorded in these rocks," Valerie Fox, a planetary scientist at Caltech and the other co-lead of the current Curiosity campaign, said in the same statement. "It wasn't just a static lake. It's helping us move from a simplistic view of Mars going from wet to dry. Instead of a linear process, the history of water was more complicated."
On its way to its current outpost, the rover first passed over what Fox called a "parking lot full of gravel and pebbles," which were too small for Curiosity to manage to drill for closer inspection. Then, in June, the rover passed into what NASA calls more complex geologic features, including an outcrop nicknamed Teal Ridge and a large boulder nicknamed Strathdon, which appears layered.
According to NASA, Curiosity should have enough power to keep exploring for a few more years.
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