Dust Storm- Opportunity EOM, the end of the beginning of a new era in robotic spaceflight |
Dust Storm- Opportunity EOM, the end of the beginning of a new era in robotic spaceflight |
Jun 5 2018, 03:05 PM
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#1
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Founder Group: Chairman Posts: 14434 Joined: 8-February 04 Member No.: 1 |
Expect a quiet few sols - http://www.lpl.arizona.edu/~lemmon/mars-tau-b.html
SOL TAU 5097 0.65 5098 0.64 5099 0.67 5100 0.64 5101 0.60 5102 0.60 5103 0.61 5104 1.55 5105 **** 5106 2.12 |
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Jun 17 2018, 07:55 PM
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Senior Member Group: Members Posts: 1669 Joined: 5-March 05 From: Boulder, CO Member No.: 184 |
How severe is this dust storm compared with others weathered by Opportunity? Estimating the total solar radiation in heavy dust conditions is an interesting exercise and the scattered light will be the main contributor when the direct radiation diminishes. I'm trying to model all this with my simulated weather imagery package. A key factor would be how much light gets absorbed for each scattering event (a single scattering albedo of about .90 in green light and .97 in the IR see figure 8). A tau of around 10 would only cut the light down about 50% if absorption wasn't a factor. I can note a Titan analog with a tau of around 8 and estimates of 10% of the visible band light getting through when absorption is factored in. Deimos' formulation in post #28 is reasonable. As mentioned more light in the IR will help for the solar panels. Serpens' YouTube video is pretty impressive.
-------------------- Steve [ my home page and planetary maps page ]
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Jun 18 2018, 12:19 AM
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#3
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Senior Member Group: Members Posts: 1057 Joined: 17-February 09 Member No.: 4605 |
How severe is this dust storm compared with others weathered by Opportunity? ..... A key factor would be how much light gets absorbed for each scattering event (a single scattering albedo of about .90 in green light and .97 in the IR A tau of around 10 would only cut the light down about 50% if absorption wasn't a factor...... This may help (or not). https://www.swsc-journal.org/articles/swsc/...swsc150027.html The maximum tau assessed by Opportunity in 2007 was 5.5. The maximum assessed this time around before she went dark was 10.8 and this may have increased. This doubling of the tau, ignoring the airmass variable means that direct insolation would be 0.005 that enjoyed by opportunity at the height of the 2007 storm. EDIT. An update by A.J.S. Rayl. http://www.planetary.org/explore/space-top...torm-sleep.html An interesting extract: “The dust here is thicker than anything I have ever encountered, going back to Viking missions,” said MER Deputy Principal Investigator Ray Arvidson ........It’s dark, like the end of twilight dark.” Paolo. described it as basically "the difference between a full sunshine day and a full moon night kind of state". Even a minor increase in tau over the 10.8 value and all ambient light would go. |
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