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Opportunity Parks Itself In Front Of A Field Of "Cobbles"
Pasadena CA (JPL) Aug 15, 2005 After months of being the "other rover" as she struggled across some pretty barren plains of sand and blueberries, Opportunity has again taken center stage. One of the things we've been wondering about for awhile was whether the blueberries are the same everywhere, or whether they change from place to place if you travel far enough. We're now several kilometers south of Eagle and Endurance, and the answer is the the blueberries here are indeed different. Opportunity did our first RAT hole in quite a few months this week, and the MI images of it are different from anything we've seen before. The berries are more numerous here, and some seem to be smaller than any we've ever seen. And interestingly, some don't appear to be round. We're still debating what this means, but clearly the hematite is distributed a bit differently here than it has been in any other rocks we've seen at Meridiani. If you've been following the images closely, you've probably noticed that something pretty weird happened to our RAT hole between Sol 546 and Sol 549. The images we got on 546 were pretty nice, and they showed that we had a nice clean RAT hole, but the floor of the hole was a little bit out of focus. So before we drove away, we decided to hit it one more time, on Sol 549. Those images, though, are a mess, with lots of crud in the hole. It looks as if we had never brushed it, though we always use the RAT brushes to remove the cuttings from a hole. What happened, apparently, is that there was a pretty substantial wind event sometime between Sols 546 and 549 that blew a bunch of cuttings back into the hole. So the 546 images are the best that we're going to get for this hole... that's life. And while this wind blast had quite an effect at ground level, it doesn't seem to have done much for Opportunity's solar arrays. That's okay, though, since we're currently in pretty good shape power-wise. Opportunity has moved on, and we're now parked at what could turn out to be one of the more scientifically important spots that we've encountered in quite awhile. One mystery we've been dealing with for a long time is the origin of the little dark "cobbles" that we occasionally see out on the plains. There are two theories. One is that they're pieces of ejecta... stuff that has been thrown out of nearby craters by impacts. If so, that's really interesting, since they're clearly made of something different from the blueberry-laden sulfates we see everywhere. If they're ejecta, then presumably they're pieces of whatever lies below the blueberry-laden sulfates, which is a material we've never seen. The other theory is that they're meteorites. That'd be interesting too, though it'd tell us less about Mars than if they're martian rocks. Both theories make sense, and both have precedents... Bounce Rock, which we found just outside of Eagle Crater, was a piece of ejecta from a crater pretty far away. Heat Shield Rock, which we found just south of Endurance, was a meteorite. Opportunity is parked right in front of a field of cobbles now, and we're spending the weekend taking APXS and Moessbauer data on a couple of them. So we should know soon enough. The other puzzle we may be able to go after here are the mysterious "rinds" that we sometimes see on rocks at Meridiani. These look like hard outer shells on some parts of some outcrops, and they're darker and a little redder than the rock that they encrust. The outcrop right in front of Opportunity now has some beautiful rinds on it, among the best we've ever seen. So once we nail the cobble problem, we may go after the rinds next. Over at Gusev, Spirit is on the move. We're done with our work in the Voltaire region, having just finished up a pretty thorough IDD investigation of a rock called Assemblee. This thing turned out to have a crazy composition, with by far the highest levels of chromium that we've ever seen on Mars. A weird one. So now we're headed toward the summit, and as I write this on Sunday afternoon we just finished a beautiful drive of something more than thirty meters. The end-of-drive Navcams from Sol 573 show a feature on the skyline that's either the summit or something very close to it. I think we're going to make it. Community Email This Article Comment On This Article Related Links Mars Rovers at JPL Mars Rovers at Cornell SpaceDaily Search SpaceDaily Subscribe To SpaceDaily Express Mars News and Information at MarsDaily.com Lunar Dreams and more
Spirit Heading To 'Home Plate'
Pasadena CA (JPL) Jan 09, 2006Last week Spirit completed robotic-arm work on "El Dorado." The rover used all three of its spectrometers plus the microscopic imager for readings over the New Year's weekend. |
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