Curiosity didn't have to go very far or spend too much time looking on the Red Planet to answer one of the mission's fundamental questions. According to NASA, Curiosity has determined that Mars could have supported living organisms in the past. Assistant Professor James Wray is on the rover's science team.
These results from Curiosity are very exciting and, for me, unexpected! We have been hunting clay minerals on Mars for years now, because of the neutral-pH, possibly long-lasting wet conditions they imply. We've seen them in many places, but always from nearly 250 km away (i.e., from orbit). Actually, on the other side of Mars, Opportunity may be sitting on clay-rich rocks right now, but it can no longer measure mineralogy, so we can't be 100 percent sure. So it is, first of all, very reassuring that Curiosity's CheMin instrument has now "proven" that clays are there, in the same way you would do so on Earth. Even more importantly, the rock we drilled is 25 percent clay! So there was enough water around to convert a significant fraction of its original volcanic minerals into water-rich clays. From orbit we can usually only say that a rock has clays (or doesn't), not whether it's 2 percent clay or 25 percent. Twenty five percent is much more exciting.
We landed in Gale crater because we could see clay minerals there from orbit, as well as sulfate salts that may have formed from water of a different chemistry. But those orbital signatures are localized on Mt. Sharp, five to 10 km south of where we landed. The area we drilled in is covered by dust, so from orbit we see no clay signatures there, nor sulfates. But once we brush off or drill through the dust, we find both minerals are there. It prompts the question: "If we could just dust off the entire surface of Mars, how much more widespread would these minerals turn out to be?"
Our prime objective in this two-year mission was to study a habitable environment on Mars, and we have had the good fortune to achieve that only seven months in, without even driving (yet) to the area that drew us to Gale crater in the first place. We'll continue to refine our search for organic matter in these rocks. Then it will be fascinating to drive into new terrains elsewhere in Gale and explore how habitable conditions waxed and waned over time.
Photo: At the center of the image from NASA's Curiosity rover is the hole in a rock called "John Klein" where the rover conducted its first sample drilling on Mars. The drilling took place on Feb. 8, 2013, or Sol 182, Curiosity's 182nd Martian day of operations. Several preparatory activities with the drill preceded this operation, including a test that produced the shallower hole on the right two days earlier, but the deeper hole resulted from the first use of the drill for rock sample collection (NASA/JPL-Caltech/MSSS).
For more information, or to schedule an interview, please contact: