A Discussion on Dust on Opportunity's Solar Panels

reply to post by qmantoo

I still feel that we should be seeing these 5mm spherules blown about into piles since this article linked above from the UK Daily Mail says that NASA was concerned about the rovers possibly being adversely affected.

Yes, it says that Opportunity might have power problems because of the dust.
It does not say anything about problems for Curiosity, and there were none.

Originally posted by qmantoo
Now, if it may possibly affect something the size of a car, why not a 5mm spherule?

Because a 5mm spherule does not have any complex mechanical parts or sensors that can be jammed, blocked abraded or otherwise screwed-up by dust getting in the works, that's why.

Distract and avoid

neither of your posts addresses the issue and like politicians answers a totally un-asked question. I asked if the rovers could be affected by a dust storm and high winds, why would the 5mm blueberries escape being blown about into piles by the wind?

reply to post by qmantoo

I asked if the rovers could be affected by a dust storm and high winds, why would the 5mm blueberries escape being blown about into piles by the wind?

And you provided no reason to think that the rovers would be affected by a dust storm and high winds, other than a loss of power due to reduced sunlight (a problem that Curiosity does not have).

Originally posted by qmantoo
Distract and avoid

neither of your posts addresses the issue and like politicians answers a totally un-asked question. I asked if the rovers could be affected by a dust storm and high winds, why would the 5mm blueberries escape being blown about into piles by the wind?

The only effect is the accumulation of dust on the solar panels, which doesn't apply to Curiosity as it has none.

Points you raise in this thread are being answered, you're just stubbornly backing away.

The Spirit rover graph posted earlier shows a steady decrease over approx 400 sols. If there were a global dust storm at the time, lasting that long, gradually worsening, and then suddenly clearing up, it would be common knowledge and supported by images. Here are Spirit images from sol 399, when the electricity production was very low: marsrover.nasa.gov... Does it look like they were taken in a thick dust storm?

Originally posted by qmantoo
Distract and avoid

Wrong and wrong...

Originally posted by qmantoo
neither of your posts addresses the issue and like politicians answers a totally un-asked question.

...and wrong again.

Originally posted by qmantoo
I asked if the rovers could be affected by a dust storm and high winds, why would the 5mm blueberries escape being blown about into piles by the wind?

Your question was answered directly and concisely here:

Originally posted by Saint Exupery

Remember that Mars' atmosphere is only 1/50 to 1/100th the density of Earth's atmosphere. That means that an 80-knot wind on Mars would not be strong enough to knock-over a child. Now, according to this article...

Martian dust ... is less than 30 micrometres in diameter.

...which is ~1/167th the diameter of one of your 5mm blueberries. Volume goes up as the cube, so assuming similar density, the 5mm ball of hematite has over four-and-a-half MILLION times the mass of each dust grain.

It should be obvious that in such an environment, winds that can lift particles not much bigger than talc would not budge larger, pea-sized rocks, even in Mars' reduced (0.38%) gravity.

Originally posted by qmantoo
I see none of this kind of evidence which I would have expected.

This is the crux of the problem: It's a different planet. Your expectations may not be valid.

That's why the spherules are not getting blown around. As for the effect on the rovers, at least three people have told you what the concerns are mechanically, electrically and in terms of data-gathering.

I think I may have found the source of your false-expectations. The Daily Mail article to which you linked opens with this lurid first line:

NASA is hoping that their red planet rovers won’t roll over in the face of a massive dust storm.

A wind strong enough to threaten the rovers' stability certainly would blow the hematite balls around. However, no such wind exists on Mars. The maximum wind observed by the Viking landers during their multi-year missions (which included global dust storms) was ~70mph, which, when you allow for Mars' lower air pressure, is equivalent to a light breeze (~7mph) here on Earth - enough to blow dust & sand, but not pebbles.

Thus, the statement by the Daily Mail is utter fabrication is totally unsupported by any statement by NASA or JPL. The press release on which the article is based expresses no such concern. Instead, it merely states,

...the Opportunity rover would be affected most. More dust in the air or falling onto its solar panels would reduce the solar-powered rover's energy supply for daily operations. Curiosity is powered by a radioisotope thermoelectric generator, rather than solar cells. The main effects of increased dust in the air at its site would be haze in images and increased air temperature.

The "Daily Fail" strikes again.

...which is ~1/167th the diameter of one of your 5mm blueberries. Volume goes up as the cube, so assuming similar density, the 5mm ball of hematite has over four-and-a-half MILLION times the mass of each dust grain.

It should be obvious that in such an environment, winds that can lift particles not much bigger than talc would not budge larger, pea-sized rocks, even in Mars' reduced (0.38%) gravity.

What I still cannot understand in spite of these explanations is how the dust manages to be blown off the solar panels to clean them, yet not be piled up into mini dunes in the lee behind every rock on Mars.

I also dont understand how dust devils can leave tracks on the surface which can be seen from space if they are not strong enough to move small 5mm spherules.

Phoenix rover had a wind instrument which blew in the wind. That must take some force which would possibly be enough to blow blueberries around?

I see some inconsistencies here.

reply to post by qmantoo

I also dont understand how dust devils can leave tracks on the surface which can be seen from space if they are not strong enough to move small 5mm spherules.

What does the width of a dust devil track have to to with how much force the wind carries? But have you seen pictures of undisturbed blue berries in a dust devil track?

That must take some force which would possibly be enough to blow blueberries around?

Who said they aren't blown around? How do you think this happened?

I see some inconsistencies here.

Only because you aren't really thinking about it or tend to disregard information that contradicts your thoughts.

Originally posted by qmantoo
What I still cannot understand in spite of these explanations is how the dust manages to be blown off the solar panels to clean them, yet not be piled up into mini dunes in the lee behind every rock on Mars.

Are you still maintaining that the wind never changes direction?

Originally posted by qmantoo
I also dont understand how dust devils can leave tracks on the surface which can be seen from space if they are not strong enough to move small 5mm spherules.

Which part of "four-and-a-half MILLION times the mass of each dust grain" are you having trouble understanding?

Originally posted by qmantoo
Phoenix rover had a wind instrument which blew in the wind.

No, it didn't. Link

Originally posted by qmantoo
That must take some force which would possibly be enough to blow blueberries around?

Wind instruments that take "some force" to move are useless in a Martian environment. For maximum sensitivity, an anemometer should be able to move in response to the slightest puff of air.

Originally posted by qmantoo
I see some inconsistencies here.

They are not inconsistencies; they are simply things that you do not understand.
There's nothing wrong with that. I don't understand mineralogy, gardening, biochemistry or the rules of cricket, among other things (though I am curious about all of them).

Just because you don't understand these things, that does not mean that there are not other people who do understand these thing (or, for that matter, that these things cannot be understood because they are actually signs of massive fraud perpetrated by crypto-fascist Illuminati aligned with the Rand Corporation, in conjunction with the saucer people under the supervision of the reverse vampires ).

People who do understand are answering your questions and trying to help you understand.
Quite frankly, it's getting kind of exasperating that you ignore all the answers, and keep asking the same previously-answered things over and over again.

So the answers you're getting don't match your expectations. Tough. Your expectations are not valid. Welcome to the real world.

Ok, so it was Pathfinder which had the windsock. The page I wen to had about 6 days images of the windsock and all had no movement. ( mars.jpl.nasa.gov... )
Anyway thanks for all your efforts to explain things to me.

By the way, I just love the 2x strange non-blueberry circular 'battery-thingy' in that image Phage. Thanks for that. What is the original link to that photo please?

reply to post by qmantoo

By the way, I just love the 2x strange non-blueberry circular 'battery-thingy' in that image Phage.

I just pulled it off ATS without checking the source. Seems that was a mistake. Sorry. A reverse image search provided the original source. Not Mars. Earth blueberries. So I guess you can disregard what I said about that image.
unews.utah.edu...

Here's one that is on mars. The balls got on top of that rock somehow.
www.sciencebuzz.org...

I just pulled it off ATS without checking the source. Seems that was a mistake. Sorry. A reverse image search provided the original source. Not Mars. Earth blueberries. So I guess you can disregard what I said about that image.

no problem.

Originally posted by qmantoo
Ok, so it was Pathfinder which had the windsock. The page I wen to had about 6 days images of the windsock and all had no movement. ( mars.jpl.nasa.gov... )

Cool! Thanks for the link. Pathfinder was one of my favorite missions. It was the first Mars lander in 20+ years, and the image quality was so much better than the Vikings. If you haven't done so already, find some red/blue 3D glasses and check-out the color anaglyphs.

I think I see here some dust piled up here. (Sol 145)

Can you supply a link for that image please? Quite often I have Mars pictures on my pc and cannot remember where I got them from.

Actually I see some tracks as well. but thats a subject for another thread - perhaps.

reply to post by qmantoo


If you're replying to me, I made that mosaic out of raw images from mars.jpl.nasa.gov...

It's just that I have assembled many mosaics / panoramas from Curiosity before, and can recall seeing various features here and there.

sorry wildespace, yes it was to you.
Ok, it doesn't matter. Thanks.

reply to post by Phage


It is a shame that NASA did not install a brush tool or some type of cleaning tool on the Robotic arm that could slowly but surely keep those panel clean as energy is availible to do so.

Mars have dust devels and I believe both rovers have been hit by them over the years and have had their panels slightly cleaned.

You can read about them here. Space.Com

In fact, just a day before Opportunity photographed the dust devil, Martian wind helped clean some of the dust off of the rover's solar array, which increased electricity output from that array by more than 10 percent.

Not that it matters too much but it's closer to 10 years on Mars not 5 years.

Another image of sand and dust piled up against rocks. Hmm, I wonder what created those mini-dunes...
www.nytimes.com...



Latest Curiosity images are also showing small dunes.
mars.jpl.nasa.gov...
mars.jpl.nasa.gov...