The Storm, Dust storm of 2007 |
The Storm, Dust storm of 2007 |
Jul 5 2007, 05:57 PM
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#1
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Member Group: Members Posts: 710 Joined: 28-September 04 Member No.: 99 |
Oh no...This is getting bad:
The new and potentially bleak outlook is a stark shift from the prognosis earlier this week. The dusty squall has reduced direct sunlight to Mars' surface by nearly 99 percent, an unprecedented threat for the solar-powered robotic explorers. If the storm keeps up and thickens with even more dust, officials fear the rovers' batteries may empty and silence the robotic explorers forever. Opportunity's energy-gathering ability has been slashed to a dangerous 280 watt-hours-enough power to light only three 90-watt light bulbs. "The worst-case scenario is that enough dust in the sky decreases solar energy to the point that we have to shut down too many things to save power," Lemmon said. "The rovers keep their battery alive by keeping their electronics alive." "The reality of the situation is that we're limited as to what we can do from the ground by cutting power use," Callas said. "If it continues to worsen and stay that way, it's a survivability issue for Opportunity. If Mars wants to kill the rovers, it can." http://www.space.com/news/070705_dusty_rovers.html |
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Jul 19 2007, 01:42 AM
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#2
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Administrator Group: Admin Posts: 5172 Joined: 4-August 05 From: Pasadena, CA, USA, Earth Member No.: 454 |
I'm doing some research to write about the storm and just thought I'd share some now-comical quotes from one of A. J. S. Rayl's rover updates from January 31 this year, regarding tau values measured by Spirit:
QUOTE When the tau levels rise to 1, it limits the activities the rovers can perform and values of 2 or greater can be fatal. During most of Spirit's mission on Mars, tau values have ranged anywhere between 0 and 1. Not surprisingly then, there was real concern over the holiday weekend about whether or not Spirit was going to make it to its anniversary when the tau suddenly rose to .9 and then tipped to 1 at the end of December, and the rover's power levels began dropping....On Sol 1066 (New Year's Day 2007), the tau rose to 1.136 causing the rover's solar array energy to drop to a low 276 watt-hours, a level it had experienced briefly before in the depths of winter at Low Ridge....Once the engineers at JPL reanalyzed Spirit's power situation, they realized the rover could survive on less power now that spring was moving in. "For this time of year -- when temperatures are getting warmer and it's not getting super cold at night -- the amount of power that Spirit needs for survival is considerably less than it was in the wintertime. What the rover needs to survive in winter is something between 200 and 250 watt-hours, whereas now we can survive on something less than 200 watt-hours, so even with relatively low power numbers we're able to safely operate the vehicle and get lots done," Squyres explained. How naive we were...I'm thinking of you, Opportunity, hunkered down under storm-darkened skies... --Emily -------------------- My website - My Patreon - @elakdawalla on Twitter - Please support unmannedspaceflight.com by donating here.
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Jul 19 2007, 02:45 PM
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#3
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Senior Member Group: Members Posts: 4252 Joined: 17-January 05 Member No.: 152 |
I'm doing some research to write about the storm and just thought I'd share some now-comical quotes from one of A. J. S. Rayl's rover updates from January 31 this year, regarding tau values measured by Spirit: Remember that that was spring, and this is mid-summer, so we need less power to survive now, since temperatures are higher. Also the panels are much cleaner now! At the time that article was written we were only recently reawakened from our winter sleep, when we had barely enough power to survive, and so no doubt a tau of 2 would have been fatal!
... How naive we were...I'm thinking of you, Opportunity, hunkered down under storm-darkened skies... |
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