The Inquisitor
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Mars Rovers Caught in Severe Dust Storm
July 20, 2007: Having explored Mars for three-and-a-half years in what were missions originally designed for three months, NASA's Mars rovers Spirit and Opportunity are facing perhaps their biggest challenge.
For nearly a month, a series of severe Martian summer dust storms has affected the rover Opportunity and, to a lesser extent, its twin, Spirit. The dust in the Martian atmosphere over Opportunity has blocked 99 percent of direct sunlight to the rover, leaving only the limited diffuse sky light to power it. Scientists fear the storms might continue for several days, if not weeks. "We're rooting for our rovers to survive these storms, but they were never designed for conditions this intense," says Alan Stern, associate administrator of NASA's Science Mission Directorate, Washington.
The animated global map of Mars, below, shows how the opacity of the Martian atmosphere has increased since late June. Blue areas denote clear air, red areas are thick with dust:
If the sunlight is further cut back for an extended period, the rovers will not be able to generate enough power to keep themselves warm or operate at all, even in a near-dormant state. The problem is, Mars is a very cold planet, and the rovers depend on electric heaters to keep some of their vital core electronics warm.
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Before the dust storms began blocking sunlight last month, Opportunity's solar panels had been producing about 700 watt hours of electricity per day, enough to light a 100-watt bulb for seven hours. When dust in the air reduced the panels' daily output to less than 400 watt hours, the rover team suspended driving and most observations, including use of the robotic arm, cameras and spectrometers to study the site where Opportunity is located.
On Tuesday, July 17, the output from Opportunity's solar panels dropped to 148 watt hours, the lowest point for either rover. On Wednesday, Opportunity's solar-panel output dropped even lower, to 128 watt hours.
NASA engineers are taking proactive measures to protect the rovers, especially Opportunity, which is experiencing the brunt of the dust storm. The rovers are showing robust survival characteristics. Spirit, in a location where the storm is currently less severe, has been instructed to conserve battery power by limiting its activities.
"We are taking more aggressive action with both rovers than we needed before," said John Callas, project manager for the twin rovers at the Jet Propulsion Laboratory, Pasadena, Calif.
By Opportunity's 1,236th Martian day, which ended Tuesday, driving and all science observations had already been suspended. The rover still used more energy than its solar panels could generate on that day, drawing down its battery. "The only thing left to cut were some of the communication sessions," Callas said.
To minimize further the amount of energy Opportunity is using, mission controllers sent commands on Wednesday, July 18, instructing the rover to refrain from communicating with Earth on Thursday and Friday. This is the first time either of the rovers has been told to skip communications for a day or more in order to conserve energy. Engineers calculate that skipping communications sessions should lower daily energy use to less than 130 watt hours.
A possible outcome of this storm is that one or both rovers could be damaged permanently or even disabled. Engineers will assess the capability of each rover after the storm clears.
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obmar
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Hope everything goes well,
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The Inquisitor
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They have already far outlived their supposed lifespan on Mars. Whatever the scientists reap from these machines is just icing on the cake.
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obmar
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Opportunity had outlived its intended lifespan by many folds...
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The Inquisitor
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Here is something about the rover spirit's recent adventures there:
Evidence of A Wet Martian Past
A shallow trench made by Spirit's dragging right front wheel uncovered some of the best evidence Spirit has found for ancient water-rich environments in Gusev Crater -- bright patches of almost pure, fine-grained silica (SiO2). On ancient Earth, warm, evaporating coastal waters deposited fine silica in shallow sediments. In Yellowstone National Park, hot, mineral-laden waters deposit fine-grained silica around geysers and hot springs. The discovery of silica-rich deposits on Mars adds compelling new evidence of ancient environments that might have been favorable for life.
Spirit acquired this false-color view of the remarkable, light-colored soil patch with the panoramic camera on the rover's 1,198th sol, or Martian day of exploration (May 17, 2007), more than three years after landing on Mars.
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obmar
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ThanksIs this the Rover?
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The Inquisitor
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I think it could be either one. I can't tell the difference from either one.
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