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Posted by: sranderson Oct 18 2005, 05:47 PM

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....

Posted by: helvick Oct 18 2005, 06:28 PM

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.

Posted by: ljk4-1 Oct 18 2005, 07:18 PM

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

Posted by: vikingmars Oct 18 2005, 08:18 PM

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...)

Posted by: sranderson Oct 18 2005, 09:12 PM

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

Scott

Posted by: helvick Oct 18 2005, 09:30 PM

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%.

Posted by: vikingmars Oct 19 2005, 05:22 AM

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 !

Posted by: helvick Oct 19 2005, 10:25 AM

Handy site to keep an eye on this storm feature as it develops (or fades).
http://elvis.rowan.edu/marswatch/images/ and their http://elvis.rowan.edu/marswatch/dust/

Posted by: pioneer Oct 19 2005, 02:36 PM

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

Posted by: fredk Oct 20 2005, 11:45 PM

Update on dust storm http://skyandtelescope.com/news/article_1617_1.asp 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.

Posted by: sranderson Oct 22 2005, 02:32 PM

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

Posted by: SigurRosFan Oct 24 2005, 06:55 PM

Latest storm picture from Ed Lomeli of Sacramento, CA:

Posted by: ljk4-1 Oct 24 2005, 07:00 PM

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.

Posted by: ElkGroveDan Oct 24 2005, 08:04 PM

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

Posted by: deglr6328 Oct 24 2005, 09:31 PM

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.

Posted by: Bob Shaw Oct 24 2005, 09:34 PM

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

Posted by: Bob Shaw Oct 24 2005, 09:37 PM

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

Posted by: jamescanvin Oct 25 2005, 01:01 AM

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

Posted by: slinted Oct 28 2005, 11:09 AM

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!

Posted by: djellison Oct 28 2005, 11:23 AM

I wonder what imagery Damien Peach has managed to get.

Doug

Posted by: Sunspot Oct 28 2005, 11:29 AM

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

Posted by: Marcel Oct 28 2005, 11:41 AM

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...

Posted by: Bill Harris Oct 28 2005, 12:32 PM

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

Posted by: akuo Oct 28 2005, 12:42 PM

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.

Posted by: ljk4-1 Oct 28 2005, 01:01 PM

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

Posted by: Tman Oct 28 2005, 01:49 PM

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?

Posted by: alan Oct 28 2005, 02:13 PM

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

Posted by: Rakhir Oct 28 2005, 07:50 PM

"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

Posted by: slinted Oct 28 2005, 08:16 PM

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.

Posted by: paulanderson Oct 28 2005, 08:49 PM

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.

Posted by: Nirgal Oct 28 2005, 09:19 PM

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

Posted by: JRehling Oct 28 2005, 09:24 PM

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.

Posted by: Rakhir Oct 28 2005, 09:26 PM

"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

Posted by: mike Oct 28 2005, 09:37 PM

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..

Posted by: Tman Oct 28 2005, 09:55 PM

Mike, you have to start with the link and guidance in my post#26. http://www.unmannedspaceflight.com/index.php?showtopic=1556&view=findpost&p=24766

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

Posted by: Vladimorka Oct 28 2005, 09:57 PM

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

Posted by: helvick Oct 28 2005, 10:56 PM

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

From http://elvis.rowan.edu/marswatch/images/

Posted by: Bill Harris Oct 29 2005, 01:59 AM

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

http://marsrovers.jpl.nasa.gov/gallery/all/1/f/625/1F183677901EFF63TUP1212R0M1.HTML

http://marsrovers.jpl.nasa.gov/gallery/all/1/r/625/1R183677952EFF63TUP1315R0M1.HTML


--Bill

Posted by: RNeuhaus Oct 29 2005, 03:02 AM

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

Posted by: Sunspot Oct 29 2005, 10:45 AM

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

Posted by: slinted Oct 29 2005, 11:36 AM

http://www.arksky.org/ has captured the storm activity again tonight, to which I've added Opportunity's position.

Posted by: helvick Oct 29 2005, 02:49 PM

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 http://tes.asu.edu/webdata/dust_mov/dust_mov_sm.html .

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 http://www.tnni.net/~dustymars/MetTrendDust.htm

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

Posted by: Bill Harris Oct 29 2005, 11:46 PM

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

Posted by: Bob Shaw Oct 30 2005, 12:41 AM

Bill:

We're talking End Of Mission!

Bob Shaw

Posted by: Bill Harris Oct 30 2005, 01:27 AM

That's what I was afraid of...

--Bill

Posted by: helvick Oct 30 2005, 09:39 AM

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

Posted by: Nirgal Oct 30 2005, 12:37 PM

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"

Posted by: helvick Oct 30 2005, 02:57 PM

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.

Posted by: dot.dk Oct 30 2005, 07:51 PM

Ok, the dust storm has hit Meridiani



Good luck Oppy

Posted by: djellison Oct 30 2005, 09:58 PM

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/627/1F183860973EFF63%23%23P1211L0M1.JPG


Doug

Posted by: OWW Oct 30 2005, 10:25 PM

There IS more dust over meridiani:

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

Posted by: djellison Oct 30 2005, 10:40 PM

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

Posted by: Bill Harris Oct 30 2005, 11:08 PM

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

Posted by: Sunspot Oct 30 2005, 11:18 PM

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

Posted by: Ames Oct 30 2005, 11:29 PM

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


Nick

Posted by: Sunspot Oct 30 2005, 11:35 PM

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

Posted by: dot.dk Oct 30 2005, 11:36 PM

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

Posted by: jamescanvin Oct 30 2005, 11:58 PM

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

Posted by: Bill Harris Oct 31 2005, 12:58 AM

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

Pass the popcorn, please...

--Bill

Posted by: CosmicRocker Oct 31 2005, 05:39 AM

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.

Posted by: Ames Oct 31 2005, 10:16 AM

new pictures...

http://nasa.exploratorium.edu/mars/opportunity/forward_hazcam/2005-10-31/

Posted by: dot.dk Oct 31 2005, 10:32 AM

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

Posted by: Tman Oct 31 2005, 03:17 PM

This Rear Hazcam is additional one from sol 627:

http://marsrovers.jpl.nasa.gov/gallery/all/1/r/627/1R183861024EFF63%23%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.php?showtopic=1556&view=findpost&p=24937

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

Posted by: Cugel Oct 31 2005, 03:28 PM

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?

Posted by: ljk4-1 Oct 31 2005, 03:29 PM

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.

Posted by: Bill Harris Oct 31 2005, 03:30 PM

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

Posted by: Tman Oct 31 2005, 03:42 PM

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

Posted by: Ames Oct 31 2005, 03:44 PM

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

Posted by: tedstryk Oct 31 2005, 03:46 PM

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

Posted by: tedstryk Oct 31 2005, 03:49 PM

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.

Posted by: Marcel Oct 31 2005, 03:56 PM

Did Pathfinder actually see one ? Don't remember.

Posted by: helvick Oct 31 2005, 04:08 PM

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

Posted by: helvick Oct 31 2005, 04:32 PM

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.

Posted by: Bill Harris Oct 31 2005, 05:01 PM

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

Posted by: RNeuhaus Oct 31 2005, 05:07 PM

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

Posted by: DEChengst Oct 31 2005, 05:48 PM

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

Posted by: djellison Oct 31 2005, 09:24 PM

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

Doug

Posted by: RNeuhaus Oct 31 2005, 09:50 PM

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

Posted by: tedstryk Oct 31 2005, 10:19 PM

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

Posted by: djellison Oct 31 2005, 10:41 PM

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

Doug

Posted by: ilbasso Oct 31 2005, 10:53 PM

The Pathfinder did indeed image several dust devils. See http://ivis.eps.pitt.edu/courses/mars/papers/ferri_et_al__jgr__2003.pdf for a description.

The Pathfinder atmospheric station also recorded the wind and pressure changes associated with a dust devil passing over the lander. See http://nssdc.gsfc.nasa.gov/planetary/marspath/dustdevil.html.

Posted by: jamescanvin Oct 31 2005, 11:10 PM

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

Posted by: Sunspot Oct 31 2005, 11:40 PM

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

Posted by: tedstryk Oct 31 2005, 11:45 PM

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.)

Posted by: djellison Nov 1 2005, 08:13 AM

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

Posted by: Bill Harris Nov 1 2005, 11:04 AM

From the Mission Status at the NASA/JPL site:

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

Posted by: RNeuhaus Nov 2 2005, 04:17 PM

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

Rodolfo

Posted by: general Nov 2 2005, 08:01 PM

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

Posted by: Burmese Nov 2 2005, 08:11 PM

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.

Posted by: Tman Nov 2 2005, 09:58 PM

Has anybody seen a new picture of the dust storm? http://www.arksky.org/cgi-bin/asoimglog.pl?selobject=Mars&selmonthb=10&seldayb=28&selyearb=2005&selmonthe=11&seldaye=2&selyeare=2005 seems to be too eastward (or too westward? ) now. The last pictures there are showing the storm went more in a southward direction.

Posted by: avkillick Nov 2 2005, 10:12 PM

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

Posted by: ljk4-1 Nov 3 2005, 02:37 PM

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).

Posted by: Tman Nov 3 2005, 06:20 PM

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 http://webgis.wr.usgs.gov/website/mars%5Fhtml/viewer.htm:

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.

Posted by: jamescanvin Nov 4 2005, 12:20 AM

Very nice! Thanks Tman.

Posted by: Bill Harris Nov 18 2005, 04:36 AM

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

Posted by: lyford Nov 18 2005, 07:37 AM

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?

"http://www.imdb.com/title/tt0083798/quotes"

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

Posted by: jaredGalen Nov 18 2005, 09:27 AM

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

Posted by: edstrick Nov 18 2005, 10:25 AM

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.

Posted by: slinted Nov 18 2005, 11:19 AM

The bright ...splotch is a persistant feature that showed up sometime between the last sundial images taken on http://www.lyle.org/mars/imagery/1P183226471ESF63DGP2111L4M1.JPG.html and the first ones taken on http://www.lyle.org/mars/imagery/1P183308946ESF63DGP2124L4M1.JPG.html. 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.

Posted by: Bill Harris Nov 18 2005, 01:29 PM

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

Posted by: RNeuhaus Nov 18 2005, 03:32 PM

The pictures on Sundial are of different filters: LR1, LR2, LR3, LR4, LR5, LR6, LR7, and LR8. Maybe, due to different filters, we are seeing different clarity and colors on the top ball and also the borders of the surface.

Rodolfo

Posted by: mike Nov 18 2005, 04:01 PM

Maybe we should land a rover that has nothing but ball-topped poles of varying heights and see what ends up plastered to them as the sols pass. Call it "Maybe We'll Get Lucky".

It looks to me like that splat was created from a single collision, and that whatever hit it wasn't dense enough to damage the pole in any noticeable way.. Salty snowball?

Posted by: ljk4-1 Nov 18 2005, 04:04 PM

Do students and others still use the sundials to tell the local time of day on Mars with? I haven't heard much about that since they first landed.

Posted by: RNeuhaus Nov 18 2005, 04:42 PM

Visit the following URL to learn more about Sundial : http://athena.cornell.edu/kids/sundial.html

1) It is used to calibrate and adjust colors of PANCAM (4 different colors on the corners)
2) It is used to see the martian's sky color (two halph circle mirror plates on the border)
3) To track the time on Mars watch by its star corona on the bottom of the pole. (only used by students).


The sundials, positioned on each rover's rear solar panel, will help the Athena team adjust the rovers' panoramic cameras. Scientists will use the colored blocks in the corners of each sundial to calibrate the color in images of the landscape so that Mars can be seen in its true colors. And pictures of the shadows cast by a sundial's center post, or gnomon, will allow adjustments for brightness.

"On Mars, you don't know what color anything is," said Nye. "The Martian sky is so pink that it makes everything pink, and so you want to know if the object you're looking at is really pink or if it's pink light bouncing off the sky."

The grayscale calibration rings surrounding the gnomon represent the orbits of Mars and Earth, with two dots representing the planets. A keen observer might note that the dots are in the positions that Mars and Earth would have been in at the time of the Surveyor landing.

Each sundial is inscribed with the words "Two Worlds, One Sun" and bears the name "Mars" in 17 languages, including Bengali, Inuktituk, Lingala and Malay-Indonesian, as well as ancient Sumerian and Mayan. Four gold panels along the sides of the sundials are inscribed with stick-figure drawings of people, as well as a message to future Mars explorers:

"People launched this spacecraft from Earth in our year 2003. It arrived on Mars in 2004. We built its instruments to study the Martian environment and to look for signs of life. We used this post and these patterns to adjust our cameras and as a sundial to reckon the passage of time. The drawings and words represent the people of Earth. We sent this craft in peace to learn about Mars' past and about our future. To those who visit here, we wish a safe journey and the joy of discovery."

Rodolfo

Posted by: ljk4-1 Nov 18 2005, 06:59 PM

It looks like the dust storm is starting to fade. This image is posted here with permission.

I wonder why the 1971 storm was global and not any since?

Posted by: dot.dk Nov 18 2005, 08:47 PM

Indeed the dust storm is over and a fresh new cleaning event was in order

Rover update at JPL/NASA

http://marsrovers.jpl.nasa.gov/mission/status.html#opportunity

Posted by: ElkGroveDan Nov 18 2005, 08:51 PM

It's left over from the "cleaning event."

Posted by: helvick Nov 18 2005, 10:02 PM

720 watt hours is nice and healthy, the cleaning event seems to have boosted Oppy's energy generating capacity by about 10%. Before this dust storm she was generating somewhere around 670 watt hours and the total insolation has dropped slightly so I had been expecting that she would return to around 650 watt hours when the dust cleared.

Posted by: Nirgal Nov 18 2005, 10:22 PM

helvick,

what would be your best estimate of Oppy's remaining life time, if it were limited by solar power alone ... a) without further cleaning events or assuming one or two additioanl 10% cleaning events during the remaining life time ?
From your latest chart it would seem that we could expect solar power to last well into February, right ?

Nirgal
... who still can't stop dreaming the Victoria dream

Posted by: helvick Nov 18 2005, 11:41 PM

I now think that it will be well past February, in fact I don't think that declining Solar power will be an issue at all until very close to mid winter (around the start of July 2006). She now has a very good chance of being able to generate enough power to survive for at least another martian year and a half. Other things are probably becoming more critical though but power is definitely looking very good indeed.

A few weeks back I estimated that the power levels at mid winter on her second year would be around 260 Watt hours but that was based on the then current level of dust loading. This cleaning event has added about 70 watt hours of capacity at the moment and if the pattern of dust deposition between now and Sol 870 (the Sol with the lowest insolation ~ July 5 2006) follows the pattern from Sols 1 to 196 then my estimate needs to be increased by 35-40 watt hours.

So I think we're now looking at a minimum of 295-300 Watt hours for a few days in mid winter. That is survivable, particularly if the planners\drivers can find some handy 10-15 degree north facing slopes to pitch out on for a week or two in the depths of winter.

Posted by: antoniseb Nov 18 2005, 11:47 PM

I had the impression that Opportunity was close to the Equator, and that we are using the term "winter" to denote the time period when Mars is near aphelion. I don't think that being pitched 10-15 degrees could help much of anything, except perhaps to allow gravity to help the dust to roll off the solar panels.

Posted by: ElkGroveDan Nov 18 2005, 11:51 PM

Heck they can find a slope like that on any large sand dune.

That raises another question though. Does anyone know if the wheels can be partially retracted again? (For example to create an artifical tilt to the rovers) or did they permanently lock into place upon initial deployment?

Posted by: TheChemist Nov 19 2005, 12:04 AM

I could be wrong, but straight from memory I think some pyros were fired to deploy the wheels, so probably they can't be retracted back.

Posted by: bergadder Nov 19 2005, 12:07 AM

Locked on deployment..


In terms of power, was there an issue of battery cycles and can we tell if they are degrading?

Posted by: helvick Nov 19 2005, 12:58 AM

When I'm talking about "winter" I'm referring to the Southern Hemisphere winter. Sorry I should have been specific, I was being sloppy.

I've tended to refer to Winter instead of being specific because there is a "seasonal" cycle even for Opportunity. You are correct about winter in this context being when Mars is near aphelion but the seasons that result from obliquity still have an effect on insolation even at the equator. The top of atmosphere insolation level varies according to the mars:sun distance (going from ~500-~700 watts/m^2 from aphelion to perihelion) but the surface insolation at any point also varies as the planet's obliquity causes the suns Zenith angle to change throughout the year. For any point (even one on the equator) this leads to a change in insolation with two maxima during the year (at the equinoxes), this effect is smaller for Opportunity than the first effect but the sun's zenith angle in Mid SH winter is 25 degrees (to the North, at noon).

Solar panel efficiency is improved under such conditions by ensuring that the panel is tilted towards the position of the noon sun. This is particularly important during the Martian Southern Hemisphere winter season because Tau drops to around 0.3-0.4 over much of the planet at that time and when Tau is low solar panels become very sensitive to the incidence angle of the incoming sunlight. When Tau is high, as happens during the SH summer, the solar panels generate a significant percentage of their power from diffuse light and do not suffer significantly if they are not precisely aligned to the noon sun.

The difference might not seem that much (40-50 Watt hours in mid SH winter) but the difference between pointing in a favourable direction and an unfavourable one can easily be 80 watt hours. Spirit's power levels dropped briefly from 370 watt hours on sol 203 to 288 watt hours on sol 204 because a drive terminated early and left her pointing in the wrong direction. Likewise Opportunity benefited extensively during the last winter season because she spent most of her time pitched between 15 and 20 degrees on the North facing inner slopes of Endurance.

Posted by: ToSeek Nov 19 2005, 04:45 PM

%&*#$ pigeons are everywhere!

Posted by: lyford Nov 19 2005, 08:49 PM

I believe you are referring to these Martian pigeons?

Posted by: Bill Harris Nov 21 2005, 04:10 AM

On dust devils-- or the failure to see them-- at Meridiani: I was looking at MOC imagery for examples of the anatolia features and found these two images near the Oppy landing site. A histogram equalize was done to enhance low-contrast features and behold, (apparent) dust devil tracks.

FWIW; open to interpretation. But applying the Duck Criteria....

--Bill

Posted by: Marcel Nov 21 2005, 08:42 AM

I remember them being designed to be able to do about a 1000 cycles. That (to my opinion and guess) is going to be THE problem in the end. As far as i can tell, the degradation of the batteries can be assessed easy when charge and recharge currents, -times and -characteristics are compared over time.

Is this data available to the public ? Can we ask for this numbers in some way ? It's pretty important considering how much more adventure we can expect on the long run.

There might be a possibility of solely operating on solar energy directly from the arrays when batteries get worse, there will be no (or not much) energy left at night however to prevent the Warm Electronic Box to drift outside temp. design limits. Eventually, they'll probably freeze to death.

But that might take another Martian year !

Posted by: dvandorn Nov 21 2005, 01:31 PM

Open to interpretation is right... frankly, I don't see dust devil tracks there. I see wind tails and I see compression artifacts. Note that there are two very obvious dark lines in the image on the right that don't appear on the image on the left -- a sure sign that these are being enhanced out of the noise.

There's nothing of the curly-q type of tracks you see, for example, at the Gusev site. Whatever shown in these images that's true wind effects, IMHO, is from straight-line winds.

-the other Doug

Posted by: Phil Stooke Nov 21 2005, 02:28 PM

I'm not as sceptical as the other Doug (in this case anyway). The broad dark bands don't look at all like wind tails or compression artifacts to me. The fact that they seem different between images doesn't mean anything, as these are two different images from different dates, so changes would be quite reasonable. The very narrow dark bands are the anatolia-style linear depressions. The Gusev streaks are curlier but that might be related to the topographic differences between sites.

Phil

Posted by: RNeuhaus Nov 21 2005, 03:28 PM

I think that the differences between the Dust Devil and Wind Streak are of its traces. The DD *never* trace a stright line since it is subjected by the convencion of two different temperatures between the surface and the atmosphere which are very dynamic. Otherwise, the Wind Streak is of a constant or prominent wind and its force changes the color of surface in stright lines due to different kind of sand or dust on the surface. Then the typical atmospheric phenomenas: DD-> Gusev, SW -> Meridiani

Rodolfo

Posted by: Bill Harris Nov 21 2005, 04:44 PM

Admittedly, some streaks are jpg artifacts and wind tails but more of the dark tracks do curve and show characteristics of whirlwinds or dust devils. I suspect that the differences between here and at Gusev are caused by higher windspeeds on this flat plain and by the less-dusty armored surface.

The images do show the narrow anatolia lineations well. Phil's recent polar pans shown here do suggest that the "micro craters" seen Erebus-ward are indeed caused by sapping and not impact; I seen crater chains in this region.

--Bill