It's widely accepted that Mars was once home to streams and rivers, and that parts of its ice cap are composed of frozen water. But could there still be moisture in the planet's soil? After analyzing a sample collected by the Curiosity rover, a team of scientists has found strong evidence that Martian dirt contains traces of water — and that it could be recovered and used in manned Mars missions.
The discovery was made possible by a February mission to collect a soil sample from Mars. A month earlier, Curiosity had used a brush to sweep up dust from the planet's surface, but the material didn't lend itself to deep analysis. So the bot made its way to the Gale Crater, a site that's thought to have held water in the past. From there, Curiosity drilled a 2.5-inch-deep hole in the ground, scooping up the cylinder of dirt inside. The real work, however, had just begun. To figure out what was in the dirt, the Mars Science Laboratory Team used a device known as the Sample Analysis at Mars, or SAM. As lead author Laurie Leshin, dean of Rensselaer Polytechnic Institute, puts it, a baby aspirin-sized piece of the sample was fed into a tiny cup in Curiosity, then heated to temperatures of 835 degrees Celsius (over 1,500 degrees Fahrenheit.) The gases that came off revealed the composition of the soil inside.
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