Dust Storm Options

[sranderson]

Spaceweather (www.spaceweather.com) is reporting a dust storm on Mars visible in amateur telescopes. Hope we don't get too much dust-fall on the solar panels....

[helvick]

Worth keeping an eye on but hopefully this will be short lived and not turn into a major storm. Chryse is a common location for "localised" storms so lets hope that the Rovers' luck holds out and this isn't the start of a big one.

[ljk4-1]

Worth keeping an eye on but hopefully this will be short lived and not turn into a major storm. Chryse is a common location for "localised" storms so lets hope that the Rovers' luck holds out and this isn't the start of a big one.

On the other hand, it may provide a good science opportunity to study a Martian dust storm at the source.

[vikingmars]

Hope this one will NOT reach any MER rover !
Here is how it really looked like at Viking 1 landing site at Chryse on sol 324 of its mission during a storm (with image taken on sol 282 as a comparison)...
Enjoy ! (if I may say...)

Attached thumbnail(s)

 

[sranderson]

Wow. Gets dark doesn't it. Are those piles of dust laying on the deck of the Viking Lander?

Scott

[helvick]

Hope this one will NOT reach any MER rover !
Here is how it really looked like at Viking 1 landing site at Chryse on sol 324 of its mission during a storm (with image taken on sol 282 as a comparison)...
Enjoy ! (if I may say...)

Ooh - nasty. Here's a chart of the Solar Panel output of a hypothetical MER-V1 roving around the Viking-1 site in 1976\77. If such a beast occurs Oppy and MER will see solar panel output reduce by about 75%.

[vikingmars]

Wow.  Gets dark doesn't it.  Are those piles of dust laying on the deck of the Viking Lander?

Scott

The piles of dust were made trough soil sampling activities when soil was put inside the collector funnels of the soil analysis and biology instruments. Wind effects were quicky observed as piles of dust moved swiftly across the deck of the Lander which had a grid painted on it to measure such movements... However, at the end of the mission, after having endured 5 big dust storms, the VL1 lander deck and covers were losing their gray blue color and parts of them were already looking red-brown...
And, thanks to nuclear power energy, VL1 was still working !

[helvick]

Handy site to keep an eye on this storm feature as it develops (or fades).
Marswatch - Images and their Dust Monitoring page

[pioneer]

Hope this one will NOT reach any MER rover !
Here is how it really looked like at Viking 1 landing site at Chryse on sol 324 of its mission during a storm (with image taken on sol 282 as a comparison)...
Enjoy ! (if I may say...)

Neat. I wondered if the Viking landers were ever in a dust storm. Fortunately they had RTGs for power.

[fredk]

Update on dust storm here with short interview with a MER team member on weathering a storm.

From the latest images there, I estimate the storm is currently roughly 2000km from the closest rover, Oppy.

[sranderson]

Looks like the storm is getting bigger and it apparently has a green color when viewed from Earth. www.spaceweather.com

[SigurRosFan]

Latest storm picture from Ed Lomeli of Sacramento, CA:

[ljk4-1]

Looks like the storm is getting bigger and it apparently has a green color when viewed from Earth. www.spaceweather.com

Reminds me of a National Geographic from 1955 which declared a giant greenish patch appearing on Mars to be a huge field of some kind of plant life.

Had Mariners 4, 6, and 7 found more than just a lot of craters back in the late 1960s (leading to the assumption of Mars as a "dead" planet) and instead imaged the volcanoes, canyons, and valleys found by Mariner 9 just a few years later, it is likely we would have gone ahead with manned Mars missions in the 1980s.

[ElkGroveDan]

Latest storm picture from Ed Lomeli of Sacramento, CA:

I'll have to meet Ed. It looks like he's got a really nice telescope.

[deglr6328]

How frequently do global dust storms occur on Mars? I know there was one in 2001 and one in 1971 but that's all I'm aware of. Surely there must have been many more recorded in the last century.

[Bob Shaw]

I'll have to meet Ed.  It looks like he's got a really nice telescope.

It also looks like he's mastered the art of TouCam image-stacking - it's a joy to see amateurs taking such images!

Bob Shaw

[Bob Shaw]

How frequently do global dust storms occur on Mars? I know there was one in 2001 and one in 1971 but that's all I'm aware of. Surely there must have been many more recorded in the last century.

There's a pattern to them, based on the rather more elliptical orbit which Mars has and which leads to the southern hemisphere having a greater range of temperatures than the north - colder winters, warmer (but still frigid) summers. Just count on dust storms at oppositions!

Bob Shaw

[jamescanvin]

How frequently do global dust storms occur on Mars? I know there was one in 2001 and one in 1971 but that's all I'm aware of. Surely there must have been many more recorded in the last century.

Somewhere I heard a quote that there had been 10 recorded since 1877.

Looking into it a bit further there appear to have planet wide storms in

1877 (Schiaparelli), 1909, 1924, 1941, 1956, 1971 (Mariner 9), 1973, 1977 (x2? Viking), 1994 and 2001.

James

[slinted]

There is fresh activity being seen VERY close to Opportunity, as visible in some of the imaging done earlier today.

5:30 UT : http://marswatch.amaonline.com/10-28-050030.jpg
6:00 UT through 7:59 UT : http://www.arksky.org/asoimg/MarAF4AD5A.jpg

I took Dr. P. Clay Sherrod's 07:38 image and fit it to a JPL Solar System Sim image of the same time, which I marked with Opportunity's landing site. I transfered that mark over onto a overlapping version of the webcam image and with permission from Dr. Sherrod I present it here to you.

It isn't a perfect lineup or position marking, though as you can see, a little difference goes a long way. This one is close!

[djellison]

I wonder what imagery Damien Peach has managed to get.

Doug

[Guest_Sunspot_*]

Whoah !!! thats close. Would Opportunity be able to see this in the sky?

[Marcel]

Whoah !!! thats close.  Would Opportunity be able to see this in the sky?

I think yes. This looks in the order of tens of miles away. Oppy better start close her eyes.....or at least...find a way to point her panels to the sun as much as possible. This storm looks huge !! Any insights on the direction of atmospheric movement these time of year on Mars ? I hope it's going westward...

[Bill Harris]

BTW, by convention, and I presume that they still do this, on astronomical images of planets, South is up.

I fear that this may be not-good for Oppy. Remember that we observed wind immediately blowing evaporite dust from the tracks the other day, so there is an increase in the wind velocity from the northwest.

--Bill

[akuo]

I think this dust storm is already on top of Oppy. It looks like to me that there is one "finger" of dust extending over Oppy's position. See the comparison of these images from the original observer:

http://www.arksky.org/asoimg/MarAF4B178.jpg

This could be a very serious situation.

[ljk4-1]

I think this dust storm is already on top of Oppy. It looks like to me that there is one "finger" of dust extending over Oppy's position. See the comparison of these images from the original observer:

http://www.arksky.org/asoimg/MarAF4B178.jpg

This could be a very serious situation.

The green colors in these images - are those real or artifacts? What is causing them if they are real?

[Tman]

On the ASO website http://www.arksky.org/asoimglib.htm (by "Object to Browse:" enter Mars, and "date:" 10.28.2005) there are some weird notes about this "dust storm". Do they wonder whether it be caused by an impact?

[alan]

The green colors in these images - are those real or artifacts?  What is causing them if they are real?

The green color was mentioned at http://spaceweather.com/ on Oct 21.
It may be a combintion of the yellow dust and high blue clouds

[Rakhir]

"The storm has seven appendages that stretch in all directions.
The overall cloud is about 700 to 800 miles across.
It is spreading at a speed of about 35 mph and may become larger by the weekend."

http://www.space.com/scienceastronomy/051028_mars_storm.html

Rakhir

[slinted]

BTW, by convention, and I presume that they still do this, on astronomical images of planets, South is up.

You're absolutely correct. I rotated Sherrod's original image to north-up so as to conform to the JPL SSS image, and to make it a bit more familar for those who only know the Opportunity site from north-up maps. Sorry if that caused any confusion.

[Guest_paulanderson_*]

"The storm has seven appendages that stretch in all directions.
The overall cloud is about 700 to 800 miles across.
It is spreading at a speed of about 35 mph and may become larger by the weekend." 

http://www.space.com/scienceastronomy/051028_mars_storm.html

Rakhir

Good article, although they don't mention Sherrod's other comments (quoted below, re Tman's post #26) from the ASO web site or how close it is to Oppy. Have these kinds of odd "extensions" been seen before in Martian dust storms?

"There is an incredibly brilliant outbreak, perhaps yellow dust, between Margaritifer Sinus and Sinus Meridiani this morning, this developing from a minor yellow cloud just 24 hours ago. This feature is so bright that it is difficult to accurately image it without greatly underexposing the rest of the Martian features surrounding it. Note the (at least) seven (7) "fingers" or extensions that seem to radiate or spread outward from a large central area of unprecedented intensity. This odd area was first noted early this morning by Frank Melilo and Joel Warren and as it has rotated into view I believe that it has actually rapidly intensified in brightness. Hopefully west coast (USA) observers will get this as well.... I would appreciate the opinions and input of others, but honestly with the symmetry of the radiations emanating from this bright spot, I am not sure that we cannot rule out a catastrophic outflow, similar to that of eruption or even impact in nature. This does appear, because of the concentration in brilliance and the rapidity of development, to be extraordinary in nature."

There is also an animation now on the ASO web site.

[Nirgal]

There is fresh activity being seen VERY close to Opportunity, as visible in some of the imaging done earlier today.

OMG this is outstanding spectacular !

from the estimated spreading rate at 35mph and the close location to Opportunity it must be visibily already in the current images (at least as substantial darkening of the sky)
Too bad that the exploratorium site is down right now

So what does this storm mean for the rover ?

hopefully the degradation of solar power will be not too bad to kill the rover
eventually..

on the other hand: if Oppy survives this, then chances are that the panel are
more clean than before due to the dust cleaning effects of the high wind speeds...

This is going to become a really exciting development

[JRehling]

Whoah !!! thats close.  Would Opportunity be able to see this in the sky?

I'm not sure how "tall" a martian dust storm is. A 100 meter object would be just visible from about 20 km away. But, given that the object is dust, and the background is the already-dusty sky of Mars, it might have to be a lot closer to be visible. The easiest way to detect it would be to notice the setting sun passing into the storm.

Given the speed at which the storm is traveling, it could arrive before any image seeing it in the distance is taken -- unless an imaging campaign devoted to this is undertaken.

[Rakhir]

"Opportunity has seen some signs of the dust storm, which is apparently nearby.

Opportunity showed elevated dust levels, which were measured at an optical depth of about 1.4. The largest dust storm experienced by the rover occurred in June and rated an optical depth of about 2.

For comparison, a smoggy day in Los Angeles would rate an optical depth of about 1.0, and moderate days on Mars are about 0.5

"We started seeing more and more dusting on the solar panels," Mark Lemmon added. "And we have indirect evidence that these storms are windy. We've seen material blown out of the rover tracks over the last two weeks."

Meanwhile, Spirit has found some signs of additional atmospheric dust at Gusev Crater. She detected an optical depth of about 0.6"

http://space.com/scienceastronomy/051028_mars_storm.html

Rakhir

[mike]

There is also an animation [of the growing Mars dust storm] now on the ASO web site.

Do you have the URL handy? I'm not familiar with ASO's web site, and I've been unable to find any obvious link to this animation thus far..

[Tman]

Mike, you have to start with the link and guidance in my post#26. http://www.unmannedspaceflight.com/index.p...indpost&p=24766

It's also the site where they show the pictures and the animation.

[Vladimorka]

http://www.arksky.org/smf/index.php?topic=833.0

[helvick]

Just wondering if the "extraordinary" brightness of this dust\storm\wotsit event is related to opposition surge:

On 28 October 09:08 UT and 7 November 04:10 UT Jim Bell (Cornell University) and the Hubble Heritage team will observe Mars. The first date will be near Mars closest approach and the second near Mars opposition. This particular observation will be the closest to zero phase angle ever observed with HST and one of the scientific efforts will be to study the "opposition surge" effect.

From Marswatch

[Bill Harris]

On the FwdHazcam and RearHazcam images from Sol 625 I thought that both looked a bit "hazy" with bright shadows.

Fwd HazCam

Rear HazCam


--Bill

[RNeuhaus]

On the FwdHazcam and RearHazcam images from Sol 625 I thought that both looked a bit "hazy" with bright shadows.

Fwd HazCam

Rear HazCam
--Bill

However, these pictures were taken three days ago. Now it is sol 628. The Tau would be around 1.4 (like almost sunset) and the worst that Oppy has experienced was around 2.0 on June of last year. After that, the wind will clean again the dust from plan solars and hope it would be even better when it is close to Mogollon rim.

Rodolfo

[Guest_Sunspot_*]

I wish we could get to see some dust storm images from Odyssey, Mars Global Surveyour and Mars Express.

[slinted]

Dr. Sherrod has captured the storm activity again tonight, to which I've added Opportunity's position.

[helvick]

How frequently do global dust storms occur on Mars? I know there was one in 2001 and one in 1971 but that's all I'm aware of. Surely there must have been many more recorded in the last century.

The odds on a major planet encircling storm seem to be around 20% per Martian year or one every decade or so for us Earthlings. The last global storm was in 2001 - heres a nice write up and animation from TES .

Previous major storms were seen in 1909, 1924, 1956, 1971, 1973, 1975, 1977 (twice) and 1982 although apparently only the 1971 event is considered global in that it obscured the whole planet apart from the tops of the Tharsis peaks. Nice write up here by Jeff Beish

There was a fairly significant non planetwide storm in 2003 that was concentrated in Hellas and lasted for most of December 2003.

[Bill Harris]

Could the dust storm be a serious matter for our intrepid explorer? I am assuming that if the dust storm does hit and decrease the solar panel output to below the minimum, Oppy can go into a deep sleep mode and wait the storm out, waking up once the storm clears. And if the solar panels get dusted over, we'll wait for a cleaning event. Or am I too accustomed to Oppy being The Energizer Mars Rover?

--Bill

[Bob Shaw]

Could the dust storm be a serious matter for our intrepid explorer?  I am assuming that if the dust storm does hit and decrease the solar panel output to below the minimum, Oppy can go into a deep sleep mode and wait the storm out, waking up once the storm clears.  And if the solar panels get dusted over, we'll wait for a cleaning event.  Or am I too accustomed to Oppy being The Energizer Mars Rover?

--Bill

Bill:

We're talking End Of Mission!

Bob Shaw

[Bill Harris]

That's what I was afraid of...

--Bill

[helvick]

Bill:

We're talking End Of Mission!

Bob Shaw

We're only talking end of mission if things get really bad and stay that way. Oppy's been generating somewhere in the 600Watt/hours per day range lately. An extended period where Tau is around 2 would reduce that by 20-30% which would make things more difficult but wouldn't kill her. A really major event (Tau~ 5) would bring that down to around 240 Watt/hours which is below the level that I think she needs to survive for an extended period. Even at that level though I think there would be enough juice to wake up and blip out a "Hello I'm still more or less alive" direct to earth message.

To give you an idea what a major planetwide storm would do - the second 1997 storm had Tau > 4 for approximately 36 Sols (based on a model from Viking data) and Tau >2 for about 80 sols. It's important to remember that the general consensus is that we're too late in the season for a storm like that.

The

[Nirgal]

We're only talking end of mission if things get really bad and stay that way. Oppy's been generating somewhere in the 600Watt/hours per day range lately. An extended period where Tau is around 2 would reduce that by 20-30% which would make things more difficult but wouldn't kill her. A really major event (Tau~ 5) would bring that down to around 240 Watt/hours which is below the level that I think she needs to survive for an extended period. Even at that level though I think there would be enough juice to wake up and blip out a "Hello I'm still more or less alive" direct to earth message.

To give you an idea what a major planetwide storm would do - the second 1997 storm had Tau > 4 for approximately 36 Sols (based on a model from Viking data) and Tau >2 for about 80 sols. It's important to remember that the general consensus is that we're too late in the season for a storm like that.

The

ok, I'm confident that the Rover could survive during the duration of most dust storms but the question is: how does the storm affect the accumulation on the solar panels *after* the storm ?

I'm afraid that the wind itself ceases long before the majority of the dust (very light particles !) eventually falls out of the atmosphere:

this could be bad because all the dust that had been kicked high up into the atmosphere would now slowly trickle out of the air like snow-flakes on a windless winter day, accumulating on the solar panels without the wind necessary to blow it away ...

Question for the experts (hevlick ?): how did the dust accumulation develop after past dust storms that Oppy observed ?

on the other hand if some of the increased wind activity associated with the dust storm continues shortly after much of the dust has fallen back to the ground, then
it could even improve the solar panel situation by "wind cleaning events"

[helvick]

Question for the experts (hevlick ?): how did the dust accumulation develop after past dust storms that Oppy observed  ?

Firtly I'm not an expert - just an amateur trying to understand something that intrigues me and would really love for a real expert to chime in if there are any reading.

What should happen (obviously) is that dust that is elevated by storms and dust devils will then settle out of the atmosphere over some period of time. Assuming that the Tau levels give some indication of that rate (which is not wholly correct I know) then looking at Spirit's Tau levels at the start of the mission it appears that this settling out process at the end of the last Martian Summer took about 140-150 sols. There was a pretty big storm centered on Hellas for most of December 2003 which cleared up just as Spirit landed. Tau at the Spirit Site started off at ~0.9, fell to ~0.55 by Sol 90 and then reached a stable level of around 0.3 on Sol 145 where it stayed until ~ Sol 350. One of the published MER papers confirms that the rate of power lost due to dust deposition during the primary mission followed the expected model which I take to mean that it dropped off at approximately 0.18% per Sol. So a big storm like the 2003 one at the end of summer would mean that the long term impact of dust loss moving through autumn and into winter would be around 30% which isn't too bad. It would also be fair to say that if Tau is around 1 when the Rover's first martian anniversary happens in a few weeks then we should expect the same ~30% dust loss over the following 150 Sols. It's worth pointing out that Opportunity is currently generating power in "the high 600's" which is 15-20% below what it would generate if there was no dust loss. IF things stabilise and follow the pattern from the start of the mission then the power output at mid winter will be about 340 Watt hours unless they happen to find themselves stopped on an unfavourable inclide.

[dot.dk]

Ok, the dust storm has hit Meridiani



Good luck Oppy

[djellison]

Youcha. I think a lot of that is because of the low sun causing an awkward stretch of the JPG - but the rover has got a LOT of camera-dust recently.

This one is stretched back a bit because of the missing data and it feels very very strange..

http://marsrovers.nasa.gov/gallery/all/1/f...23P1211L0M1.JPG


Doug

[OWW]

There IS more dust over meridiani:

Taken from http://www.arksky.org/alpo/index.php
October 30th:

Attached thumbnail(s)

 

[djellison]

Obviously MOC WA will be catching this lot, but it's fortuitously also Hubble time, Jim Bell et.al. had one and have another session, so they should have caught it in all it's glory as well - a nice flow of data if they get it right from Hubble, to MOC WA, to MERB

Doug

[Bill Harris]

It may not be curtains. This is a plucky little robot.

(putting on my best William Conrad voice) Will our intrepid explorers, Rocky and Bullwinkle succumb to the dust monster? Tune in next time...

I agree with Doug, the FHazcam image may be misleading. Argh! Only _that_ image online for Sol 627, and no others. But look at the second FHazcam image posted by Doug, the reflection of the bright sky off the polished aluminum piece is _very_telling of sky conditions.

We'll know more when the other Sol 627 images are up.

--Bill

[Guest_Sunspot_*]

When I go to the JPL RAW site all I see are broken links for the latest sol 627 images.

[Ames]

When I go to the JPL RAW site all I see are broken links for the latest sol 627 images. 

Grrr! Broken links, exploritorium not updating, what's happenning to Oppy????


Nick

[Guest_Sunspot_*]

Weird, they dont show up for me in any browser I try.

[dot.dk]

You have to insert "%23%23" in the filename where it says "##"

[jamescanvin]

ok, I'm confident that the Rover could survive during the duration of most dust storms but the  question is: how does the storm affect the accumulation on the solar panels *after* the storm ?

I'm afraid that the wind itself ceases long before the majority of  the dust (very light particles !) eventually falls out of the atmosphere:

this could be bad because all the dust  that had been kicked high up into the atmosphere would now slowly trickle out of the air like snow-flakes on a windless winter day, accumulating on the solar panels without the wind necessary to blow it away ...
...

When I talked to Steve Squyres a few months back he said that dust accumulation on the panels after a storm was not a consern. Lets worry about the storm itself for now.

James

[Bill Harris]

Heck, let's sit back and watch the storm.

Pass the popcorn, please...

--Bill

[CosmicRocker]

On earth, dust storms can definitely reduce available sunlight, but they are a real pain when it rains at the same time. Then it's time for a car wash. I'm a bit worried about accumulated dust, but also hopeful some dust will blow off the panels. It probably doesn't make a lot of sense comparing this dust storm to those on earth, though.

Both the original and the 'unstretched' hazcams posted looked pretty dusty to me. But I'm with Bill on this. Pass the popcorn and the Pancams, please.

[Ames]

new pictures...

http://nasa.exploratorium.edu/mars/opportu...cam/2005-10-31/

[dot.dk]

new pictures...

http://nasa.exploratorium.edu/mars/opportu...cam/2005-10-31/

Newst pictures are 3 days old...

But somehow Exploratorium has gone crazy updating...
Looks like all Spirit images have been reloaded on the 31'st... That's gonna kill MMB

[Tman]

This Rear Hazcam is additional one from sol 627:

http://marsrovers.jpl.nasa.gov/gallery/all...23P1315L0M1.JPG

Looks more dusty too in comparison to one sol older pics.
It's the same time like this one: http://www.unmannedspaceflight.com/index.p...indpost&p=24937

It's unbelievable how we have to scrape up the pictures in these days

[Cugel]

But the shadow of the rover still looks sharp and crispy!
Most of what we're seeing is dust on the camera, isn't it?

[ljk4-1]

Did it ever show if the dust that accumulated on the Viking landers ever blew off?

Was a dust devil ever seen by them, even if its true nature was only realized years later? I can't believe that no dust devils ever passed by them even once during their operating lives.

[Bill Harris]

This didn't quite show what I'd hoped it would, but here it is for your FWIW file...

Here is a montage of four Forward Hazcam images from Sols 627, 626, 624 and 616 that semi-shows a build-up of dust in the atmosphere, but not conclusively.

--Bill

[Tman]

But the shadow of the rover still looks sharp and crispy!
Most of what we're seeing is dust on the camera, isn't it?

Think so, but it's really windy for a few days.

[Ames]

The latest hazcam pictures show the shadow as being sharp - as I would expect.
BUT the shadowed zone is lighter indicating that there is more "ambient" light.

Think of the sky here on earth and compare the shadows on a cloudless day:
1) in a smoggy city (say LA)
2) in mountains.
Both have crisp edges but the contrast in the mountains is much higher.

The latest rear hazcam images definately show a reduced shadow contrast.

Nick

[tedstryk]

I imaging the stretching of the "raws" wrecks havoc on our ability to determine how much the brightness of the seen is effected.

[tedstryk]

Did it ever show if the dust that accumulated on the Viking landers ever blew off?

Was a dust devil ever seen by them, even if its true nature was only realized years later?  I can't believe that no dust devils ever passed by them even once during their operating lives.

Dust devils were detected by other instruments. But because the Viking cameras were slow, line scanning systems, they wouldn't have shown up in images except as perhaps a funny looking line or two. This is why Pathfinder and the MERs see them - they have framing cameras.

[Marcel]

This is why Pathfinder and the MERs see them - they have framing cameras.

Did Pathfinder actually see one ? Don't remember.

[helvick]

Did Pathfinder actually see one ? Don't remember.

I don't think it saw one but they felt at least one with their wind and pressure sensors.

[helvick]

I imaging the stretching of the "raws" wrecks havoc on our ability to determine how much the brightness of the seen is effected.

True but there are a couple of things to note that can give us something to work on.
Tau=5. There will be no clear shadows at all, at noon the diffuse illumination will be about 2 orders of magnitude more intense than direct beam illumination and it's even more extreme when the solar elevation is low.
Tau=2, There will be faint shadows, diffuse lighting at midday is about 5x the intensity of the direct beam, and once again that rises significantly further from noon.
Tau=1, Clear shadows are visible but shaded areas are well illuminated. Diffuse light is about 20% higher than direct at noon. Overall daily diffuse insolation is about 80% more than direct beam.
Tau=0.5, Crisp shadows and shaded areas are noticably dark. Direct beam is ~70% more than diffuse light at noon. Total daily beam insolation is abotu 20% more than direct beam.
Tau=0.1, Extremely well defined shadows. Beam lighting is ~10x the intensity of diffuse at noon.

Things get a bit fuzzy very early\late in the day when tau is above ~0.2 as direct beam falls off rapidly at low sun angles while diffuse light falls off pretty slowly.

[Bill Harris]

Here is another evaluation of the sky brightness. Using two "similar" Rear Hazcam images, I used the bottom of the solar panel as a greycard to measure the incident light from the ground onto the panel. Selecting two 75x75 pixel apertures on the right and left sides of the panel in each image and averaging the value in each aperture, I adjusted the brightness of the two images so that the value of each aperture was the same in both images. This way, I ensured that the "greycards" had the same value and this allowed me to evaluate the relative intensities of the shadowed areas in the foreground. This is meatball photometry since it disregards a lot of variables, but I think it suggests that the shadows are brighter on Sol 627.

FWIW^2.

--Bill

[RNeuhaus]

Did it ever show if the dust that accumulated on the Viking landers ever blew off?

Was a dust devil ever seen by them, even if its true nature was only realized years later?  I can't believe that no dust devils ever passed by them even once during their operating lives.

The Meridiani Planum does not have dark strikes on the land as the product of dust devil. Hence, that zone does not occurs dust devils unless in the Gusev's basin has lots of dark strikes around the Columbia and Cook Hills. Thus, that zone is considered as North West (aprox 350 degree) to South East (80 degree) constant wind. You can see the formation of ripples: the west side of ripple, the surface is somewhat rough with minor canals toward the ripple and the east side, you will notice as a plain and smooth side due to the dust or sand accumulation by the wind.

Rodolfo

[DEChengst]

Some info from the CNN website:

"Lemmon said that data returned to Earth Friday by Opportunity showed elevated dust levels at Meridiani Planum, which were measured at an optical depth of about 1.4. The largest dust storm experienced by the rover occurred in June and rated an optical depth of about 2, he added."

(...)

"Lemmon suspects that Opportunity experienced one of the "fingers" of the storm photographed by Sherrod, adding that later atmospheric measurements were lower than the 1.4 optical depth seen earlier, but not quite at the moderate 0.5."

So it's not looking too bad at the moment. Go Oppy

[djellison]

CODE

4. What EDRs did we request?

Expected EDRs by sequence number and image type:

Sol Seq.Ver  ETH ESF EDN EFF ERP Tot  Description
--- -------- --- --- --- --- --- ---- -----------
628 p0767.03 14  0   0   14  0   28   navcam_7x1_az_288_3_bpp
628 p1663.01 6   0   0   6   0   12   navcam_3x1_az_108_1_bpp
630 p0767.03 14  0   0   14  0   28   navcam_7x1_az_288_3_bpp
630 p1663.01 6   0   0   6   0   12   navcam_3x1_az_108_1_bpp

Nothing on 629 at all, and just monitoring on the other two - perhaps something of a hunker-down-mode?

Doug

[RNeuhaus]

Yes, it will only be looking a narrow angle from west (288 degree) to south (108 degree) ... I suppose that the summer time the sun would be passing to sunset on that angle.

Or perhaps, that angle is the proposed route so the team wants to focus closer the terrain toward the Mogollon rims. It might means that the rover will advance too. I think that the only change has come out from Pancam Tracking Databaes is that now it does not show any engineering commands that previously had appeared. Still not sure but I noticed and it might be too early to jump conclusions.

Rodolfo

[tedstryk]

It spotted a few...I have some images somewhere...I will have to dig...

[djellison]

It might means that the rover will advance too.

No - when the rover drives, you ALWAYS gets Hazcam imagery, Penultimate, Ultimate, and if it's a long drive, 'Stumble' as well

Doug

[ilbasso]

The Pathfinder did indeed image several dust devils. See this paper for a description.

The Pathfinder atmospheric station also recorded the wind and pressure changes associated with a dust devil passing over the lander. See Pathfinder Dust Devil meteorology.

[jamescanvin]

Yes, it will only be looking a narrow angle from west (288 degree) to south (108 degree) ... I suppose that the summer time the sun would be passing  to sunset on that angle.

That's not the way I read the PDT (Pancam Data Tracking, I think it's time to abbreviate this) I beleve that it reads

navcam_7x1_az_288_3_bpp

7 navcam frames centred at az 288 degrees

navcam_3x1_az_108_1_bpp

3 navcam frames centred at az 108 degrees

Note that 288 - 108 = 180. i.e the centres are in opposite directions. Also note that 10 navcam frames generally make a 360 degree pan.

So these two lines should be read together as simply "A 360 degree navcam pan".

James

[Guest_Sunspot_*]

CODE

4. What EDRs did we request?

Expected EDRs by sequence number and image type:

Sol Seq.Ver  ETH ESF EDN EFF ERP Tot  Description
--- -------- --- --- --- --- --- ---- -----------
628 p0767.03 14  0   0   14  0   28   navcam_7x1_az_288_3_bpp
628 p1663.01 6   0   0   6   0   12   navcam_3x1_az_108_1_bpp
630 p0767.03 14  0   0   14  0   28   navcam_7x1_az_288_3_bpp
630 p1663.01 6   0   0   6   0   12   navcam_3x1_az_108_1_bpp

Nothing on 629 at all, and just monitoring on the other two - perhaps something of a hunker-down-mode?

Doug

Looking at the pancam site the last few days, im sure data was received the next sol, which would be sol 630.

[tedstryk]

I worked with some of those Patfinder images once. This is what I got by merging color data with some dust devil imagery. The rest of the stuff I did was lost in a computer crash, and I haven't had the will to go redo it, given the quality of the MER images.



Also, here are a few other images (I did NOT process these, but, as they are scraps from the crash as well, I have no idea where they came from.)

[djellison]

Ted have you ever found the equiv of Pathfinder RAD data. It's listed on the PDS - but you have to be a Nasa funded researcher to grab a copy, I've only been able to grab something that's basically, not too different to the plain EFF's

I think the Pancam Tracking site might be a bit out of date, perhaps they're 'doing' something to it.

Doug

[Bill Harris]

From the Mission Status at the NASA/JPL site:

Sol 620: The rover's observations used its panoramic camera to observe a feature informally named "Mogollon Rim" (for an area in Arizona) and onboard magnets. It also checked for dust devils.

My feeling is that the dust devils, "convective wind events" or whatever occur at Meridiani just as at Gusev. Whereas Gusev is dustier, we are able to see the dust devils and the tracks they leave but Meridiani has a cleaner surface covered with the blueberry pavement/armor and the DDs are less visible.

--Bill

[RNeuhaus]

That's not the way I read the PDT (Pancam Data Tracking, I think it's time to abbreviate this) I beleve that it reads

navcam_7x1_az_288_3_bpp

7 navcam frames centred at az 288 degrees

navcam_3x1_az_108_1_bpp

3 navcam frames centred at az 108 degrees

Note that 288 - 108 = 180. i.e the centres are in opposite directions. Also note that 10 navcam frames generally make a 360 degree pan.

So these two lines should be read together as simply "A 360 degree navcam pan".

James

jamescanvin: Good and smart hint! I didn't know that to make a 360 panoramic pictures needs 10 Navcam.

Rodolfo

[general]

Oppy's dusty weekend
http://marsrovers.jpl.nasa.gov/mission/sta...tml#opportunity

[Burmese]

always a new twist for the programmers:

"...The morning after a deep sleep, the rover wakes up when solar panels start putting out a prescribed level of energy. However, a dust storm in the Meridiani region reduced sunshine enough on the morning of sol 628 that Opportunity did not wake from deep sleep early enough for the first scheduled activities of that sol. The rover's onboard software properly put Opportunity into self-protective automode for the day,..."

So the programmers now have to program in anticipation of the expected solar panel output as diminished by expected tau for the coming day.

[Tman]

Has anybody seen a new picture of the dust storm? Arkansas Sky Observatory seems to be too eastward (or too westward? ) now. The last pictures there are showing the storm went more in a southward direction.

[avkillick]

Now that's a concept! Miss the alarm - so stay in bed for the day. I could work with that

always a new twist for the programmers:

"...The morning after a deep sleep, the rover wakes up when solar panels start putting out a prescribed level of energy. However, a dust storm in the Meridiani region reduced sunshine enough on the morning of sol 628 that Opportunity did not wake from deep sleep early enough for the first scheduled activities of that sol. The rover's onboard software properly put Opportunity into self-protective automode for the day,..."

So the programmers now have to program in anticipation of the expected solar panel output as diminished by expected tau for the coming day.

[ljk4-1]

FOR RELEASE: 9;00 am (EST) November 3, 2005

PHOTO NO.: STScI-PRC05-34a

MARS KICKS UP THE DUST AS IT MAKES CLOSEST APPROACH TO EARTH

NASA's Hubble Space Telescope snapped this picture of Mars on October
28, within a day of its closest approach to Earth on the night of
October 29. The large regional dust storm appears as the brighter,
redder cloudy region in the middle of the planet's disk. This storm,
which measures 930 miles (1500 km) has been churning in the planet's
equatorial regions for several weeks now, and it is likely responsible
for the reddish, dusty haze and other dust clouds seen across this
hemisphere of the planet. Hubble's Advanced Camera for Surveys High
Resolution Imager took this image when the red planet was 43 million
miles (69 million km) from Earth. Mars won't be this close again to
Earth until 2018. Mars is now in its warmest months, closest to the Sun
in its orbit, resulting in a smaller than normal south polar ice cap
which has largely sublimated with the approaching summer.

Credit: NASA, ESA, The Hubble Heritage Team (STScI/AURA),
J. Bell (Cornell University), and M. Wolff (Space Science
Institute)

For the full story, please visit:

http://hubblesite.org/news/2005/34

http://heritage.stsci.edu/2005/34

For additional information, please contact Jim Bell, Cornell
University, 402 Space Sciences Building, Ithaca, NY 14853,
(phone) 607-255-5911, (e-mail) jfb8@cornell.edu, or

Mike Wolff, Space Science Institute, 4750 Walnut St., #205,
Boulder, CO 80301, (phone) 262-790-1356, (e-mail)
wolff@spacescience.org, or

Keith Noll, Hubble Heritage Team, Space Telescope Science
Institute,3700 San Martin Drive, Baltimore, Md. 21218, (phone)
410-338-1828, (fax) 410-338-4579, (e-mail) noll@stsci.edu.

The Space Telescope Science Institute (STScI) is operated by
the Association of Universities for Research in Astronomy, Inc.
(AURA), for NASA, under contract with the Goddard Space Flight
Center, Greenbelt, Md. The Hubble Space Telescope is a project
of international cooperation between NASA and the European
Space Agency (ESA).

[Tman]

Woow, that's another highlight from Hubble! Mars in action.

And last but not least, it give us the chance to look closer at Oppy's position in comparison to the storm from 10.28.

Tried to overlay a map from USGS Mars General Image Viewer:

http://www.greuti.ch/oppy/oppy_dstormkarte.gif

Oppy's position is directly next to the "M" from the "MER". A bit more to the right than the arrow in the official image today.

[jamescanvin]

Woow, that's another highlight from Hubble! Mars in action.

And last but not least, it give us the chance to look closer at Oppy's position in comparison to the storm from 10.28.

Tried to overlay a map from USGS Mars General Image Viewer:

http://www.greuti.ch/oppy/oppy_dstormkarte.gif

Oppy's position is directly next to the "M" from the "MER". A bit more to the right than the arrow in the official image today.

Very nice! Thanks Tman.

[Bill Harris]

There does not appear to have been a dust deposition problem with the recent dust storm; it seems to have been a cleaning event.

Sundial L456 images from Sol 594 and Sol 644.

--Bill

[lyford]

This would be good news - seems the answer is blowin in the wind after all.

Though am I the only one that thinks "cleaning event" sounds like some horrible euphemism?

" Heinamackafrau?"

I will gladly trade eine kleine spreckles on the hazcam for clean solar panels.

[jaredGalen]

Sundial L456 images from Sol 594 and Sol 644.

--Bill

What do you think that white stain on the left of the dial is?

[edstrick]

I was looking at that marking on the left side of the sundial post and it's irregular border and the only thing that came to mind was "spark discharge".... I'm wondering if it's ultrafine dust adhering in a pattern involving a corona discharge or something. Wild-ass-guess speculation, but that thing's weird!

I'd love to see current pics of that aluminum pole with a donut on top.. I've forgotten which antenna that is... Earlier in the missions, there were two elliptical patches of dust adhering to it in a distinctive pattern that I suspected might be due to electrostatic attraction or adhesion of dust involving strong electromagnetic fields at that point. I'd have to extensively dig for a pic that shows it well.

[slinted]

The bright ...splotch is a persistant feature that showed up sometime between the last sundial images taken on sol 620 and the first ones taken on sol 621. That sol was less than a week before the large dust storm that came so close to Opportunity, and during the period described by Dr. Mark Lemmon in the space.com story quoted by Rakhir in post #33 of this thread:

"We started seeing more and more dusting on the solar panels," he added. "And we have indirect evidence that these storms are windy. We've seen material blown out of the rover tracks over the last two weeks."

The appearance of this marking (which, based on the conditions at the time, I'd guess to be a windblown dust deposit) might have been the moment of peak winds, and probably "points" in the direction from which the wind came.

[Bill Harris]

I have no idea what that white "splat" is. I noticed it as I processed the image, but decided to let comments here go where they may. "White" colors imply sulfate salts and the splattered nature of the mark and it's timing implies a wind-blown collision, so I'll let it go at that. I'll imagine (or not _imagine_) that it is bacterial or frost...

What is the sundial post made of? I'm thinking anodized aluminum, but I can't find a reference on it.

--Bill