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The Storm, Dust storm of 2007
OWW
post Jul 5 2007, 05:57 PM
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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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hendric
post Jul 11 2007, 05:14 AM
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Is it possible that the Tau reading is just a single point on a line, ie the Tau could be 4.6 now, but could be lower or higher before and after that reading. Tau comes from looking at the sun, right? So power produced could be slightly off from what you expect because the dust isn't consistent either across the sky, or from morning to evening.


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Space Enthusiast Richard Hendricks
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"The engineers, as usual, made a tremendous fuss. Again as usual, they did the job in half the time they had dismissed as being absolutely impossible." --Rescue Party, Arthur C Clarke
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Pertinax
post Jul 11 2007, 12:29 PM
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QUOTE (hendric @ Jul 11 2007, 01:14 AM) *
Is it possible that the Tau reading is just a single point on a line, ie the Tau could be 4.6 now, but could be lower or higher before and after that reading. Tau comes from looking at the sun, right? So power produced could be slightly off from what you expect because the dust isn't consistent either across the sky, or from morning to evening.


I would be strongly suspicious of any answer other than 'absolutely'.

The dust in the atmosphere certainly varies on short time scales -- they do on earth. Also, as you noted the extinction of sunlight would be greater for lower sun angles than higher for any given tau, as the effective optical depth increases with a lower sun (sun having to shine though a greater volume of air & dust). I have wondered myself how for a constant tau the sky appearance (including of course scattered light) would vary.

FWIW: http://marswatch.astro.cornell.edu/Bell_etal_SkyColor_06.pdf

-- Pertinax
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Posts in this topic
- OWW   The Storm   Jul 5 2007, 05:57 PM
- - kungpostyle   This is starting to look like it might need it...   Jul 5 2007, 06:32 PM
- - helvick   99% drop in direct beam flux is Tau of around 5.2....   Jul 5 2007, 06:49 PM
- - Bobby   I saw this article on Yahoo News and thought every...   Jul 5 2007, 06:59 PM
- - Stu   Hope this doesn't get any worse... don't w...   Jul 5 2007, 08:11 PM
- - mchan   It would be awesome if the pictures can show somet...   Jul 5 2007, 08:26 PM
- - Stu   I know there's no way we'd ever get pics l...   Jul 5 2007, 08:31 PM
- - Oren Iishi   Can the rover be shut down until the storm passes?...   Jul 5 2007, 08:46 PM
- - MarsIsImportant   Yes, but the heaters need to be on to keep the ele...   Jul 5 2007, 09:04 PM
- - Tom Tamlyn   What is the impact of the storm on dust deposition...   Jul 5 2007, 09:32 PM
- - djellison   Strangely, if I get this right - regional dust sto...   Jul 5 2007, 09:37 PM
- - ngunn   It must all fall down when the wind stops. If it c...   Jul 5 2007, 09:51 PM
- - djellison   What happened after the, admitedly much more modes...   Jul 5 2007, 09:56 PM
|- - helvick   QUOTE (djellison @ Jul 5 2007, 10:56 PM) ...   Jul 5 2007, 11:49 PM
- - Sunspot   Are there any pictures of the dust storm anywhere?...   Jul 5 2007, 10:06 PM
|- - slinted   QUOTE (Sunspot @ Jul 5 2007, 03:06 PM) Ar...   Jul 5 2007, 11:05 PM
- - Pavel   Would not the air be warmer if the airborne dust i...   Jul 5 2007, 10:34 PM
- - djellison   That's true - I remember the depths of Spirits...   Jul 5 2007, 10:39 PM
|- - ustrax   it is my oppinion that if Oppy survives this we sh...   Jul 5 2007, 10:53 PM
- - Tom Tamlyn   Is the MRO's Mars Climate Sounder able to retu...   Jul 5 2007, 11:17 PM
- - john_s   Here's another nice site for amateur images of...   Jul 5 2007, 11:53 PM
- - slinted   Dr. Lemmon has an update on his dust devil page, w...   Jul 6 2007, 12:22 AM
|- - Pando   QUOTE (slinted @ Jul 5 2007, 05:22 PM) Dr...   Jul 6 2007, 03:20 AM
|- - fredk   QUOTE (Pando @ Jul 6 2007, 03:20 AM) Tau ...   Jul 6 2007, 04:17 AM
- - Astro0   Just got some feedback that Sol 1225 Tau is 4.125....   Jul 6 2007, 05:24 AM
|- - Tesheiner   QUOTE (Astro0 @ Jul 6 2007, 07:24 AM) Jus...   Jul 6 2007, 10:59 AM
|- - diane   QUOTE (Astro0 @ Jul 6 2007, 12:24 AM) Jus...   Jul 6 2007, 05:17 PM
- - Stu   Murky sky... hang on in there, Oppy...   Jul 6 2007, 05:30 AM
- - Bobby   The dust storm has delayed Oppy from entering Vict...   Jul 6 2007, 05:52 AM
- - djellison   What with the stuck shoulder joint heater, 255 is ...   Jul 6 2007, 07:25 AM
- - belleraphon1   Dust storm.... high tau...... high winds..... Kno...   Jul 6 2007, 11:54 AM
- - sattrackpro   There is an interesting article about dust storms ...   Jul 6 2007, 12:24 PM
- - helvick   Multiple major storms do happen in some years - th...   Jul 6 2007, 01:03 PM
- - mhoward   At least she was still taking pictures on sol 1225...   Jul 6 2007, 01:54 PM
|- - tedstryk   Speaking of Hubble, it will look at Mars near the ...   Jul 6 2007, 01:57 PM
|- - Analyst   QUOTE (mhoward @ Jul 6 2007, 01:54 PM) .....   Jul 6 2007, 02:07 PM
|- - centsworth_II   QUOTE (Analyst @ Jul 6 2007, 10:07 AM) Ve...   Jul 6 2007, 02:24 PM
- - hortonheardawho   colorized Spirit sol 1244 ( July 4, 2007 ) L0 1x2:...   Jul 6 2007, 02:37 PM
- - dvandorn   I'm actually a little more worried about Spiri...   Jul 6 2007, 06:07 PM
- - akuo   Some new information in this National Geographic a...   Jul 7 2007, 12:26 AM
- - kungpostyle   Jake seems confident; best rover news I've he...   Jul 7 2007, 12:41 AM
- - mhoward   A handful of sol 1226 images are online. Just sola...   Jul 7 2007, 01:45 AM
- - MarsIsImportant   Sol 1226...look how clean the rover looks! ht...   Jul 7 2007, 05:02 AM
|- - belleraphon1   QUOTE (MarsIsImportant @ Jul 7 2007, 01:0...   Jul 7 2007, 11:56 PM
|- - belleraphon1   OK - doing a total inline quote is one thing - doi...   Jul 7 2007, 11:59 PM
- - CosmicRocker   She looked very clean, but that image should be fr...   Jul 7 2007, 06:40 AM
- - Sunspot   www.spaceweather.com reports the storm has intensi...   Jul 7 2007, 07:36 AM
- - djellison   Strong winds with the storm mean that Opportunity...   Jul 7 2007, 07:55 AM
- - vikingmars   As a reminder, here are the fully calibrated compa...   Jul 7 2007, 12:11 PM
- - Stu   Hey, welcome back vikingmars! Missed your gorg...   Jul 7 2007, 01:33 PM
- - deglr6328   how do we know how high the winds are at the surfa...   Jul 7 2007, 01:39 PM
- - djellison   Well - from the rovers we don't really. For d...   Jul 7 2007, 01:42 PM
- - CosmicRocker   Yes, whatever goes up must come down, but thanks t...   Jul 8 2007, 06:24 AM
- - djellison   another sols info on Marks page.   Jul 8 2007, 02:56 PM
|- - clt510   QUOTE (djellison @ Jul 8 2007, 09:56 AM) ...   Jul 9 2007, 01:57 PM
|- - centsworth_II   QUOTE (clt510 @ Jul 9 2007, 09:57 AM) ......   Jul 9 2007, 02:42 PM
- - Tesheiner   Letīs hope for this descending trend in the tau va...   Jul 9 2007, 04:10 PM
- - CosmicRocker   The early trend is in the hoped-for direction, but...   Jul 10 2007, 04:55 AM
|- - Pando   QUOTE (CosmicRocker @ Jul 9 2007, 09:55 P...   Jul 10 2007, 06:33 AM
- - djellison   Ignore the last Opportunity point - that's my ...   Jul 10 2007, 07:17 AM
- - jaredGalen   Out of curiosity, to reach Tau levels as we saw he...   Jul 10 2007, 09:54 AM
- - Tom Tamlyn   During Monday's Phoenix Mission press conferen...   Jul 10 2007, 02:38 PM
|- - centsworth_II   QUOTE (Tom Tamlyn @ Jul 10 2007, 10:38 AM...   Jul 10 2007, 02:48 PM
- - Pando   To cut down power consumption, they would also nee...   Jul 10 2007, 03:56 PM
- - Tom Tamlyn   Emily has posted a comprehensive discussion on her...   Jul 10 2007, 04:29 PM
|- - jaywee   QUOTE (Tom Tamlyn @ Jul 10 2007, 06:29 PM...   Jul 10 2007, 06:19 PM
- - MarsIsImportant   I've been looking for images of the magnets on...   Jul 10 2007, 07:08 PM
- - OWW   The first two are both from Sol 1217 and the last ...   Jul 10 2007, 07:46 PM
|- - MarsIsImportant   QUOTE (OWW @ Jul 10 2007, 02:46 PM) The f...   Jul 10 2007, 08:25 PM
|- - Tman   QUOTE (MarsIsImportant @ Jul 10 2007, 10...   Jul 10 2007, 09:19 PM
|- - Floyd   QUOTE (MarsIsImportant @ Jul 10 2007, 04...   Jul 10 2007, 10:52 PM
- - djellison   Yup - raw images 101. The date something appears a...   Jul 10 2007, 08:13 PM
- - Tom Tamlyn   jaywee, Helvick, the forum expert on Martian sola...   Jul 10 2007, 08:21 PM
- - djellison   http://midnightmarsbrowser.blogspot.com/ Get it. ...   Jul 10 2007, 08:27 PM
- - CosmicRocker   I just noticed this Aviation Week Article dated Ju...   Jul 10 2007, 08:58 PM
- - elakdawalla   Hi guys, I went to the Mars meeting at Caltech tod...   Jul 10 2007, 09:16 PM
- - Ant103   Hi all A few times without posting because I...   Jul 10 2007, 09:18 PM
- - helvick   That 255 whr figure for Sol 1225 is bugging me (So...   Jul 10 2007, 10:12 PM
|- - fredk   QUOTE (helvick @ Jul 10 2007, 10:12 PM) T...   Jul 11 2007, 12:06 AM
|- - Astro0   'helvick' said that figure is "buggin...   Jul 12 2007, 03:20 AM
- - hendric   Is it possible that the Tau reading is just a sing...   Jul 11 2007, 05:14 AM
|- - Pertinax   QUOTE (hendric @ Jul 11 2007, 01:14 AM) I...   Jul 11 2007, 12:29 PM
- - edstrick   high dust opacity drops daytime temperatures, but ...   Jul 11 2007, 10:51 AM
- - helvick   Thanks for the input folks. The MER team's Ta...   Jul 11 2007, 01:56 PM
- - Pertinax   For fun, a question that I can probably dig for an...   Jul 11 2007, 02:06 PM
- - climber   I was wondering if we have, here on Earth, the equ...   Jul 11 2007, 02:41 PM
|- - tty   QUOTE (climber @ Jul 11 2007, 04:41 PM) I...   Jul 11 2007, 02:55 PM
- - helvick   QUOTE Pertinax wrote: It would be fascinating data...   Jul 11 2007, 02:43 PM
- - djellison   Saharan dust landing on cars in the UK isn't u...   Jul 11 2007, 03:20 PM
- - Oersted   The Sirocco: Some nice pics here of the dust blow...   Jul 11 2007, 09:22 PM
- - djellison   Infact -thinking about it - I remember finding com...   Jul 11 2007, 09:31 PM
|- - climber   QUOTE (djellison @ Jul 11 2007, 11:31 PM)...   Jul 11 2007, 09:43 PM
- - J.J.   A similar phenomenon we have here is "muddy r...   Jul 11 2007, 09:44 PM
- - fredk   The latest navcam shows several changes in the tra...   Jul 12 2007, 03:44 PM
- - helvick   Thanks for the confirmation Astr0. I'm going t...   Jul 12 2007, 04:38 PM
- - OWW   According to this report on space.com the dust sto...   Jul 12 2007, 05:04 PM
|- - Shaka   QUOTE (OWW @ Jul 12 2007, 07:04 AM) Accor...   Jul 12 2007, 06:51 PM
- - Ant103   Good eyes fredk. I'm going to make an animatio...   Jul 12 2007, 05:58 PM
- - fredk   It occurs to me after comments in the Spirit threa...   Jul 12 2007, 07:34 PM
- - fredk   From Lemmon's dust devil page, Oppy is stable ...   Jul 12 2007, 09:45 PM
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