Clearly, they are holding back the good stuff!
Posted on 03/11/2004 9:09:35 PM PST by Phil V.
Spirit Looks Down Into Crater After Reaching Rim March 11, 2004
NASA's Spirit has begun looking down into a crater it has been approaching for several weeks, providing a view of what's below the surrounding surface.
Spirit has also been looking up, seeing stars and the first observation of Earth from the surface of another planet. Its twin, Opportunity, has shown scientists a "mother lode" of hematite now considered a target for close-up investigation.
"It's been an extremely exciting and productive week for both of the rovers," said Spirit Mission Manager Jennifer Trosper at NASA's Jet Propulsion Laboratory, Pasadena, Calif.
Dr. Chris Leger, a rover driver at JPL, said, "The terrain has been getting trickier and trickier as we've gotten close to the crater. The slopes have been getting steeper and we have more rocks." Spirit has now traveled a total of 335 meters (1,099 feet).
Spirit's new position on the rim of the crater nicknamed "Bonneville" offers a vista in all directions, including the crater interior. The distance to the opposite rim is about the length of two football fields, nearly 10 times the diameter of Opportunity's landing-site crater halfway around the planet from Spirit.
Initial images from Spirit's navigation camera do not reveal any obvious layers in "Bonneville's" inner wall, but they do show tantalizing clues of rock features high on the far side, science-team member Dr. Matt Golombek of JPL said at a news briefing today. "This place where we've just arrived has opened up, and it's going to take us a few days to get our arms around it.”
Scientists anticipate soon learning more about the crater from Spirit's higher-resolution panoramic camera and the miniature thermal emission spectrometer, both of which can identify minerals from a distance. They will use that information for deciding whether to send Spirit down into the crater.
From the crater rim and during martian nighttime earlier today, Spirit took pictures of stars, including a portion of the constellation Orion. Shortly before dawn four martian days earlier, it photographed Earth as a speck of light in the morning twilight. The tests of rover capabilities for astronomical observations will be used in planning possible studies of Mars' atmospheric characteristics at night. Those studies might include estimating the amounts of dust and ice particles in the atmosphere from their effects on starlight, said Dr. Mark Lemmon, a science team member from Texas A&M University, College Station.
Opportunity has been looking up, too. It has photographed Mars' larger moon, Phobos, passing in front of the Sun twice in the past week, and Mars' smaller moon, Deimos, doing so once.
Opportunity's miniature thermal emission spectrometer has taken upward-looking readings of the atmospheric temperature at the same time as a similar instrument, the thermal emission spectrometer on NASA's Mars Global Surveyor orbiter, took downward-pointed readings while passing overhead. "They were actually looking directly along the same path," said science team member Dr. Michael Wolff of the Martinez, Ga., branch of the Space Science Institute, Boulder, Colo. The combined readings give the first full temperature profile from the top of Mars' atmosphere to the surface.”
When pointed at the ground, Opportunity's miniature thermal emission spectrometer has checked the abundance of hematite in all directions from the rover's location inside its landing-site crater. This mineral, in its coarse-grained form, usually forms in a wet environment. Detection of hematite from orbit was the prime factor in selection of the Meridiani Planum region for Opportunity's landing site.
"The plains outside our crater are covered with hematite," said Dr. Phil Christensen of Arizona State University, Tempe, lead scientist for the instrument. "The rock outcrop we've been studying has some hematite. Parts of the floor of the crater, interestingly enough, have virtually none." The pattern fits a theory that the crater was dug by an impact that punched through a hematite-rich surface layer, he said. One goal for Opportunity's future work is to learn more about that surface layer to get more clues about the wet past environment indicated by sulfate minerals identified last week in the crater's outcrop.
Christensen said that before Opportunity drives out of the crater in about 10 days, scientists plan to investigate one area on the inner slope of the crater that he called "the mother lode of hematite."
JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover project for NASA's Office of Space Science, Washington, D.C. Images and additional information about the project are available from JPL at http://marsrovers.jpl.nasa.gov and from Cornell University at http://athena.cornell.edu.
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Guy Webster (818) 354-5011 JPL
Donald Savage (202) 358-1547 NASA Headquarters, Washington, D.C.
2004-83 =====================================================
A Deep Dish for Discovery Mar 11, 2004
On the 66th martian day, or sol, of its mission, the Mars Exploration Rover Spirit finished a drive and sent back this navigation camera image mosaic revealing "Bonneville" crater in its entirety. Spirit has spent more than 60 sols, two thirds of the nominal mission, en route to the rim of the large crater dubbed "Bonneville." The rover stopped on occasion to examine rocks along the way, many of which probably found their resting places after being ejected from the nearly 200-meter-diameter (656-foot) crater.
The science team sent the rover to "Bonneville" to find out more about where the rocks they have examined so far originated. Reaching the rim of this deep dish has been a major priority since day one.
According to science team member Dr. John Grant of Washington D.C.'s National Air and Space Museum, the "Bonneville" crater could be a giant window into the ancient past of the Gusev landing site. He said, "The rocks that we see scattered around our landing site may be ejecta from inside "Bonneville," but we won't know that for sure until we actually investigate the crater. We can look at the rocks' form and chemistry, but we don't know how they fit into the big picture. If we can find their occurrence within the walls of "Bonneville" crater, we'll be one step closer to understanding the processes that shaped the entire Gusev area over time."
Most scientists agree that a fitting prize for this long drive would be to find an outcrop of bedrock material that was not transported, but formed in the crater. When a meteorite slams into the ground and creates a crater, it throws surface debris out to the sides, revealing the older, mostly buried material, a sort of natural "road cut." The real gem would be to find exposed layers of the ancient rock within the "cut" walls of the crater, which would give scientists a peek into how the area formed. "The Gusev landing site is at least partially covered in a layer of ejecta material," said Grant. "As Mars was repeatedly pelted with meteorites, the ejecta kept piling on top of other ejecta leaving a blanket of debris and little trace of what the original surface was. We want to see beneath all that impact debris, into what is really filling the Gusev crater. Hopefully "Bonneville" crater will give us a clue to what the material is at the top of that pile."
Image Credit: NASA/JPL
Internal forces squeeze or capillary action draws a heavy brine periodically to the surface through micro-tubeules and a bead of highly mineralized water "crusts over". Moisture continues to carry minerals to the bead of crusted over brine. The water goes to vapor and slowly the bead becomes a solid from the outside inward. The stem is the brine conduit.
My organic explanation . . . uh . . . uh . . . oh well . . .
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Someone spilled their Corn Pops?
I agree. Seems to be a very old crater, that has been filled in a bit. Nothing much to see there apparently. Perhaps closer up it will get more interesting..
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How's that for speculation?
LTS
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