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Unmanned Spaceflight.com > Mars & Missions > Past and Future > MER > Opportunity
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OWW
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
kungpostyle
This is starting to look like it might need it's own topic.

http://www.space.com/news/070705_dusty_rovers.html

With Home plate and the inside of Victoria on the menu I really hope this blows over.
helvick
99% drop in direct beam flux is Tau of around 5.2. That's slightly worse than the highest Tau levels measured by the Vikings in 1977.

Edited. Doh! My bad - it's actually about 4.6 which is not quite as bad as the worst the Viking's saw in 1977.
Bobby
I saw this article on Yahoo News and thought everyone might want to see it regarding both Rovers on Mars.

Martian dust storm affecting twin rovers:

http://news.yahoo.com/s/ap/20070705/ap_on_...bvYqwxIae_737YB
Stu
Hope this doesn't get any worse... don't want to see pics like this coming down... sad.gif

Click to view attachment
mchan
It would be awesome if the pictures can show something visually dramatic like that. Unfortunately, the pictures appear to show the the landscape getting slowly murkier and murkier. An animated movie would be awesome.

It's probably not too bad if any pictures can still come down. It's bad if no pictures can come down. sad.gif
Stu
I know there's no way we'd ever get pics like that, I was just imaginin' ...
Oren Iishi
Can the rover be shut down until the storm passes? Or at least put in sleep mode?
MarsIsImportant
Yes, but the heaters need to be on to keep the electronics in safe condition. Nomatter what, Opportunity needs a certain level of power to survive. The latest news suggests that those power levels are uncomfortably close to that lower limit even with sleep mode.

This is a very unfortunate turn of events. But if opportunity survives intact, then this storm and its aftermath is an incredible new science opportunity for the rover. Let's just hope that the dust storm does Not get any worse than it has over the 4th of July.

If you believe in the Gia hypothesis, then maybe Mars was just celebrating with it own brand of fireworks! ;-) rolleyes.gif smile.gif ...the kind that some western states had to ban because of the drought.
Tom Tamlyn
What is the impact of the storm on dust deposition rates? Is the activity mostly too high in the atmosphere to blow heaps of dust onto the solar arrays?

TTT
djellison
Strangely, if I get this right - regional dust storms are quite good because they cause high wind speeds ( note the cleaning that Opportunity got just over a week ago ) - BUT I would imagine that there comes a point when the dust loading, whatever the wind speed, must cause increased deposition.

Doug
ngunn
It must all fall down when the wind stops. If it causes almost complete obscuration when it's airborne then I fear it will do the same when it settles, unfortunately.
djellison
What happened after the, admitedly much more modest regional storm, that Opportunity had in the 600-ish range - the one that made it sleep in late one morning?

Doug
Sunspot
Are there any pictures of the dust storm anywhere? This isn't looking good. sad.gif
Pavel
Would not the air be warmer if the airborne dust is consuming the solar light? It's summer in the southern hemisphere, and Mars should be close to its perihelion, so maybe the power requirements for the heater are not so high as in the middle on the winter?
djellison
That's true - I remember the depths of Spirits winter, and they mentioned that they got away with less than the 240whrs they thought they needed, because the vehicle ended up staying warmer than they expected.

Doug
ustrax
it is my oppinion that if Oppy survives this we should take to Ithaca...in shoulders!
slinted
QUOTE (Sunspot @ Jul 5 2007, 03:06 PM) *
Are there any pictures of the dust storm anywhere? This isn't looking good. sad.gif


I'm sure there are other resources for finding amateur images of Mars, but the Mars Observers Yahoo group isn't a bad place to keep track of daily images of the storm. Imaging Mars isn't too easy now , but I'm consistently impressed with what you can see even in low res images. Unfortunately, you need to join the group to read the messages/see the images.
Tom Tamlyn
Is the MRO's Mars Climate Sounder able to return observations that are helpful in understanding the current dust storms? Are the observations useful for rover operations or only for long-term assessments of the atmosphere?

TTT
helvick
QUOTE (djellison @ Jul 5 2007, 10:56 PM) *
What happened after the, admitedly much more modest regional storm, that Opportunity had in the 600-ish range - the one that made it sleep in late one morning?
Doug

The purple line is a 30 Sol moving average and the red line is a 50 sol moving average trend line on that. I had to do that in order to dampen out the noise sufficiently to see any trends at all but it means that the data in those lines is shifted to the right by 30 and 80 sols so keep that in mind.
It is pretty clear (to me maybe others differ) that stormier high Tau weather (such as seen around sol 370, 420 and 510) are followed rapidly by an increase in dust deposition rate from ~0.2% per sol to ~0.3% per sol. I would assume that the much more severe dust levels we are now seeing would result in higher deposition rates fairly soon but we'll only know for sure once it happens.
Click to view attachment

Also Pavel's comment on night time temperatures is correct - at Tau=2 night time minimum temperatures would be about 15-20 degrees warmer IIRC and I'd expect that Tau-4 would improve that again. The effect is the similar to that seen here on earth where cloud cover raises night time temperatures.

That said the stuck heater on Oppy means she draws a bit more juice than Spirit. Again IIRC the heater in question draws 15watts and is activated if the atmospheric temperature falls below -52C and stays on until it warms up past -42c - they use Deep Sleep to keep it off during the night however I think they still have to live with it being stuck on for at least two hours per Sol under the best conditions so Oppy needs about 30 Whr per Sol more than Spirit.
john_s
Here's another nice site for amateur images of Mars, and other Mars news:

International Mars Watch

John.
slinted
Dr. Lemmon has an update on his dust devil page, with some specific tau figures:
QUOTE
New, sol 1244: The recent dust storm activity has been intense for both rovers. Opportunity experience optical depths of (starting sol 1215) 1.3, 1.5, 1.7, 2.2, 2.6, 3.0, 3.3, 2.7, 3.1, 4.0, 4.1, rising from a background of 1.0. Spirit's opacity remained near 0.9 until starting on 1239 it went to 1.0, 1.0, 1.2, 1.3, 1.6, 2.4, 2.3. On sols 1239 and 1244, movies caught some dust devil activity. Sol 1240's movie did not see any activity. Recent sols have seen minor dust cleaning and deposition, but I'm not aware of major changes. The sol 1244 movie shows a much more indistinct horizon. The winds at Meridiani, especially, have probably been quite intense at times.
Pando
QUOTE (slinted @ Jul 5 2007, 05:22 PM) *
Dr. Lemmon has an update on his dust devil page, with some specific tau figures:

Tau is 4.1 now!!! ohmy.gif
fredk
QUOTE (Pando @ Jul 6 2007, 03:20 AM) *
Tau is 4.1 now!!!
That's a bit better than our estimate of 4.6 based on the 99% direct sunlight attenuation quoted in the Space.com story. From Lemmon's site it was 3.1 on sol 1223. Was that a sol 1224 figure, Pando?
Astro0
Just got some feedback that Sol 1225 Tau is 4.125.
Oppy is at 255Whr.

Pray!
Stu
Murky sky... hang on in there, Oppy...

Click to view attachment
Bobby
The dust storm has delayed Oppy from entering Victoria Crater for now:

http://www.jpl.nasa.gov/news/features.cfm?feature=1411
djellison
What with the stuck shoulder joint heater, 255 is a lot worse for Opportunity than for Spirit

Doug
Tesheiner
QUOTE (Astro0 @ Jul 6 2007, 07:24 AM) *
Just got some feedback that Sol 1225 Tau is 4.125.
Oppy is at 255Whr.

Pray!


Checked the imaging plan for sol 1226 and it's only composed of two or three tau measurements. It remember Spirit during mid-winter times and looks like the available power would be not enough to run other things.

Keep strong little rover!
belleraphon1
Dust storm.... high tau...... high winds.....

Knowledge always comes with a price......

Yes, hang in there little rovers......

Craig
sattrackpro
There is an interesting article about dust storms on the hubble-site HERE - that foretells a possible second following storm. (Hope not!)

Here's the relevant excerpt:

After three months, the storm is beginning to wane. The planet's shrouded surface has cooled, and this allowed the winds to die down and the fine dust to begin settling. However, Mars is approaching the closest point of its orbit to the Sun. Once the atmosphere begins to clear, the return of unfiltered solar radiation may trigger additional high winds and kick up the dust all over again. This one-two punch has been seen in previous Mars storms for centuries.

The article is old - but could multiple storms be caused, or have been caused in this fashion with this episode?
helvick
Multiple major storms do happen in some years - the Vikings saw two in 1977 for example.
mhoward
At least she was still taking pictures on sol 1225, and the calibration target looks clean. It's now morning on sol 1226. Let's keep our fingers crossed...



tedstryk
Speaking of Hubble, it will look at Mars near the end of this month to help with MARCI's calibration woes, but in the process, it may catch the aftermath of this.
Analyst
QUOTE (mhoward @ Jul 6 2007, 01:54 PM) *
... and the calibration target looks clean.


Very clean I have to say. Probably better than before?

Analyst
centsworth_II
QUOTE (Analyst @ Jul 6 2007, 10:07 AM) *
Very clean...

But almost no shadow. There's the rub. sad.gif
hortonheardawho
colorized Spirit sol 1244 ( July 4, 2007 ) L0 1x2:



Just a guess.
diane
QUOTE (Astro0 @ Jul 6 2007, 12:24 AM) *
Just got some feedback that Sol 1225 Tau is 4.125.
Oppy is at 255Whr.

Does anyone know what Oppy's power reserves were before the storm got bad? I assume she can withstand some days of low power input, if the batteries were well-charged before the Tau got so high.

She doesn't have to survive a whole martian winter on low power.... Hopefully just a few days.
dvandorn
I'm actually a little more worried about Spirit than I am about Oppy. This dust is all still entrained in the atmosphere, it hasn't really started to fall out yet. I don't know why, but I have this gut feeling that Meridiani may collect less dust from this storm than Gusev eventually will. Maybe because there is less overall dust accumulation on the ground at Meridiani than there is at Gusev; it just feels like Meridiani doesn't collect dust as effectively as Gusev does. (Maybe Gusev's crater rim causes a large-scale swirl in the winds that tends to make dust collect within, while the lack of any such circulation patterns at Meridiani keeps it from getting dumped on nearly as much.)

I guess I'm thinking that the dust ought to have specific patterns of fallout, based on when in the year the storms occur and what the wind patterns are like at the time. It also may have something to do with your distance from where the storms start and how they grow. It just feels like, since Oppy was closer to this storm as it formed, it may actually get away with having less of the dust dumped on it than other places on the planet -- perhaps even halfway across the globe.

Also, rather obviously, the polar caps display a process in which dust is often sandwiched between layers of dry ice. It may well be that a majority of the dust pulled up during these major storms ends up being deposited at the fall/winter pole, to which the air is flowing and where the air is precipitating out and plating itself onto the ground. That would tend to make sense from a global circulation pattern perspective.

-the other Doug
akuo
Some new information in this National Geographic article.

Jacob Matijevic is confident of rover survival.
kungpostyle
Jake seems confident;

best rover news I've heard in a couple of days!
mhoward
A handful of sol 1226 images are online. Just solar-filter images so far.
MarsIsImportant
Sol 1226...look how clean the rover looks!

http://qt.exploratorium.edu/mars/opportuni...R9P1962R0M1.JPG
CosmicRocker
She looked very clean, but that image should be from sol 1223. I suspect she is still pretty clean, despite the dust storm.

It's nice to hear that somewhat positive news from national geographic. I can't help but wonder if this would have been more of a survivability issue for the rovers if they hadn't been cleaned by the earlier winds. I also can't help but wonder if such early, cleaning winds might be expected prior to a dust storm.
Sunspot
www.spaceweather.com reports the storm has intensified and grown. blink.gif

QUOTE
MARS UPDATE: A late-June dust storm that delayed Mars rover Opportunity's descent into Victoria Crater has intensified and spread around the planet, reports veteran observer Jim Melka of St. Louis, Missouri. On July 6th, the view through Melkin's 12-inch telescope showed "a chain of five dust clouds over Mare Cimmerium," he says. "One cloud is very close to the location of the Opportunity's twin, Spirit." Stay tuned for updates.
djellison
Strong winds with the storm mean that Opportunity's going to be VERY clean as long as we don't catch a big chunk of dust when...er...the dust settles, as it were smile.gif

Doug
vikingmars
wink.gif As a reminder, here are the fully calibrated comparison pics showing the minimum of light level encountered by Viking Lander 1 on sol 324 (1977).
Tau was between 5 and 6 depending your reading sources...
Enjoy ! (if I may say...)
Stu
Hey, welcome back vikingmars! Missed your gorgeous pics!

Just for my own interest, not claiming 1000% accuracy or anything, but there's a LOT less detail visible on them that hills...

( left: June 13th, right: yestersol. )

Click to view attachment
deglr6328
how do we know how high the winds are at the surface?
djellison
Well - from the rovers we don't really. For dust to be leaving the rover it has to be 'higher' than normal. Orbital imagery can track dust, clouds etc and gauge wind speeds that way.

Just a bit of fun from the values on Mark's page. Looks like we might be seing the turn in the trend- but as you can see, Meridiani already fooled us once in that regard.

Doug
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