Posted on 01/28/2004 4:59:47 AM PST by MeneMeneTekelUpharsin
PASADENA, Calif. (AP) - Scientists were looking forward to doing further analysis on the half-inch thick layers evident in images of martian rocks sent back by the NASA rover Opportunity. Each layer represents an event in the geologic history of the Red Planet and could indicate whether the outcropping could have been formed by water. The horizontally striped and fractured slabs of bedrock rim a portion of the shallow depression and lie just a short drive from where the six-wheeled robot sits atop its lander.
"Look at the wonderful layer cake-structure in there," Steve Squyres, the mission's main scientist, said Tuesday. "It's going to be fascinating beyond words to get up close and personal with this thing." Opportunity should be able to reconstruct the geologic events that created the fine layers with its complement of cameras and scientific instruments. Scientists believe the layers were laid down over a relatively brief period - anywhere from a single day to several millennia - but billions of years ago. They piled up either as ash spewed by successive volcanic eruptions or as sediments borne by wind or water. "By stringing them together, we develop a sense of history," said Andrew Knoll, of Harvard University, a member of the mission science team.
Some scientists believe the 18-inch-high band of layered rocks is cross-bedded in part, suggesting a sedimentary origin that would require the presence of water. If so, the rocks could provide the tangible evidence NASA seeks that Mars once was a wetter place capable of sustaining life. Images taken from orbit already suggest vast amounts of water once flowed across the surface of the planet. The Opportunity rover was in good shape after its weekend landing but had developed a small, 15-watt power loss that worried NASA. It also began unfolding and successfully deployed and tested its high-gain antenna, used to communicate directly with Earth.
Engineers believe a heater in the shoulder of its robotic arm has been turning on unnecessarily when temperatures drop. Typically, the heater is needed only when the arm is in use, mission manager Jim Erickson said. "We don't normally want it on. Right now we believe it's going to be continuously on whenever it's cold enough," Erickson said. Engineers continued to monitor the situation, unsure if it could harm the rover. "We're very paranoid people," Erickson said. Opportunity's twin, Spirit, continued to convalesce, 6,600 miles around the planet. Engineers received additional data from the ailing rover that is furthering their quest to understand computer problems that last week brought its science work to a grinding halt.
Engineers believe Spirit does not have sufficient random-access memory to manage all the files in its flash memory. To prevent similar problems on Opportunity, engineers deleted recently created but unneeded computer files from its flash memory, which is similar to the memory that digital cameras use to store photographs. Opportunity should roll off its lander sometime in the next two weeks. This week it is scheduled to put to use its mini-thermal emissions spectrometer, an instrument that measures infrared radiation emitted by objects. Scientists believe Opportunity came to a rest inside either of two, 20-yard-diameter craters, said Rob Manning, manager of the entry, descent and landing portion of the mission. They expected to identify which of the two adjacent craters in coming days.
Together, the two 384-pound rovers make up a single $820 million mission. NASA launched Spirit on June 10 and Opportunity on July 7. Spirit landed Jan. 3, followed by Opportunity three weeks later. Spirit landed in Gusev Crater and Opportunity in Meridiani Planum. Measurements made from orbit by other NASA spacecraft suggest both sites once abounded in water.
Could someone knowledgeable fill me in?
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"Also, initial indications are they've found sulphur and chlorine. Wouldn't this indicate two things: 1)Mars is a very poisonous place."
No-"if" they found sulphur and chlorine, it would indicate that the lander is near an active vulcanism site of some kind (volcano, geyser, hot spring).
"2)Sulphur soaks up water, doesn't it? So, whatever water might have been there has been soaked up by the sulphur...no?"
No. Sulfur only "soaks up water" when it oxidizes to make sulfur oxides (i.e. to form sulfuric acid). Any volatile sulfides (from vulcanism) would be present as H2S (hydrogen sulfide). Since there is virtually no free oxygen in the atmosphere, the H2S is unlikely to oxidize to sulfur oxides. It WILL combine with any active metals to make metal sulfides (i.e it could corrode various parts of the lander). If the sulfur is present as free vaporous sulfur, it will "freeze out" RAPIDLY at Martian temperatures.
Temperature range info is available from the Viking landers of some years back.
See:
http://www-k12.atmos.washington.edu/k12/resources/mars_data-information/temperature_overview.html
for graphics of diurnal temperature variation.
The quick bottom line is that it varies from +1 F to -170F
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