Look at what two years on Mars has done to the Curiosity Rover (comparison images)

a reply to: Lady_Tuatha

On the surface of things, it looks to be in pretty good shape. And its still running, so that's what counts.

a reply to: Pauligirl

I wondered about the penny, didn't know that, thanks

a reply to: pheonix358



gave me a nice smile to start the day, thanks.

I also learned three things before I had even finished my caffeine...the geology nod, camera focus..and the date significance.

its shaping up to be a good day.

Thanks all.

originally posted by: qmantoo
When I posted a thread on the wind erosion and strength, many people told me that the atmosphere was not dense enough to pick up and move large pieces of sand - even when there were Martian sandstorms and dustdevils. However, NASA says the MERs have 'cleaning events' where they miraculously get cleaned by the wind and so they continue on this dirty/clean cycle and this is how they (opportunity) can continue to function without being weighed down with the dust.

As far as I can see, and my conclusion to all that has been said about the wind is that NASA and some on here who parrot them, want it both ways. They want the wind to blow forcefully when it suits them and when others point out there is no evidence for forceful winds (other than the 'dust devil video footage') theses same people argue for weak winds.

Go figure, 'cos I haven't.

I suspect there are some extra filters applied to some of these images to make them look redder or blue-er.

You could say very light winds at high speed on very light dust, kind of horses for courses. Same for weathering on the rocks, the rocks themselves are so dry and brittle on the surface they succumb to the weathering and erode in much the same manner as on Earth, it's just the forces are vastly different.
I would guess that a lot of the rock on the surface is as brittle as a cuttlefish bone, one good reason for all the weird shapes.

originally posted by: qmantoo
When I posted a thread on the wind erosion and strength, many people told me that the atmosphere was not dense enough to pick up and move large pieces of sand - even when there were Martian sandstorms and dustdevils. However, NASA says the MERs have 'cleaning events' where they miraculously get cleaned by the wind and so they continue on this dirty/clean cycle and this is how they (opportunity) can continue to function without being weighed down with the dust.

As far as I can see, and my conclusion to all that has been said about the wind is that NASA and some on here who parrot them, want it both ways. They want the wind to blow forcefully when it suits them and when others point out there is no evidence for forceful winds (other than the 'dust devil video footage') theses same people argue for weak winds.

Go figure, 'cos I haven't.

I suspect there are some extra filters applied to some of these images to make them look redder or blue-er.

I don't see what your problem is. There is a wide range of particle size and wind strength on Mars. In some areas, the conditions are right for dunes to form. Seasonal winds in some areas are strong enough to transport sand up the dune slope! There are global sand storms, wind erosion, and many other aeolian processes.

Some of the responses you got on ATS may have been in error because people did'nt have enough information. Since then, we have seen images of sand piled up against rocks. Thus, wind on Mars is strong enough to move sand grains around.

a reply to: wildespace

indeed , localised rippling sand dunes too. still amazes me how the local rocks in this picture avoided accumulations



funbox

originally posted by: wildespace
I don't see what your problem is. There is a wide range of particle size and wind strength on Mars. In some areas, the conditions are right for dunes to form. Seasonal winds in some areas are strong enough to transport sand up the dune slope! There are global sand storms, wind erosion, and many other aeolian processes.

Some of the responses you got on ATS may have been in error because people did'nt have enough information. Since then, we have seen images of sand piled up against rocks. Thus, wind on Mars is strong enough to move sand grains around.

That's right, and maybe this very clear explanation from Jim Murphy back in 1997 is a particularly good answer for qmantoo's query.


" The wind on Mars is not "strong" enough to move rocks on the surface. Even
though winds on Mars can probably reach large speeds, the atmospheric
density is so low, that the force the wind can impose on a rock is quite
small. For instance, a wind of 10 meters per second (about 20 miles per
hour) here on Earth produces a force which is four times stronger than does
a 50 meter per second wind (a bit more than 100 miles per hour) on the
surface of Mars. So, since a 20 mile per hour wind here on Earth does not
generally move rocks about on the surface (though it does raise dust), the
winds on Mars don't move rocks on the surface either.
Jim Murphy
Mars Pathfinder ASI/MET Science Team. "
So a 20mph Earth wind has four times the FORCE of a Mars wind travelling at Hurricane speed, (not hurricane force) and that makes the Martian 100mph speed wind with a force of around a 5-6mph wind on Earth in the general sense.
No doubt there are other factors like atmospheric pressure and other variables in a formula somewhere.

a reply to: Lady_Tuatha

Nice pics-She has certainly taken a few dings,and collected dust but otherwise looks good!
Pics 5 and 6 in the OP show a bank of 6 cameras/sensors-note the glass covers are dust free,although surrounded by dust.

I am not sure,but I think that may mean they use ultrasonic pulses to rid any dust from the lens/sensors-Digital SLR cameras have a similar feature,in which ultrasonics are pulsed through the CCD,in order to remove any particles of dust.

They must be keeping those lens/sensors clean somehow.

a reply to: jtrenthacker

I was thinking more.....#5 is alive! Bwahaha!

Mars looks pretty much like the cats litter box. I wonder if that cat is still around. Maybe the holes were chewed into the tracks.

originally posted by: smurfy


You could say very light winds at high speed on very light dust, kind of horses for courses. Same for weathering on the rocks, the rocks themselves are so dry and brittle on the surface they succumb to the weathering and erode in much the same manner as on Earth, it's just the forces are vastly different.
I would guess that a lot of the rock on the surface is as brittle as a cuttlefish bone, one good reason for all the weird shapes.

Smurfy, I would love the winds to be either strong enough to erode or not strong enough to erode. Either way I can point to (to me) weird occurrances if either of these are true. Of course it might be just that I dont understand the complexities of the conditions there, however I would have thought there would be consistency from NASA etc.

It is merely another point which makes me believe there is something fishy going on up there. But, thats just me.

This is a useful thread because it documents the differences over time and thats what we need later down the road when something strange happens.

Completely off topic, but I would love to see a recent satellite best-resolution view of Spirit in its last resting place. Previous rovers appeared to have been dismantled (probably blown apart due to the high winds!)

a reply to: Lady_Tuatha

Brilliant thread, this is good science and will provide the first real study of erosion rate and material degradation in the martisan environment, still look's better than it might have down here though in the same time period.

originally posted by: funbox
indeed , localised rippling sand dunes too. still amazes me how the local rocks in this picture avoided accumulations

And I will once again express my ongoing surprise at how many rocks on Mars appear jagged and unweathered, as even small winds carrying tiny grains (and the occasional global dust storm) will wear rocks nice and smooth after a few thousand years. Which leads me to think that there are some pretty powerful and active forces churning the surface up either occasionally or periodically.

...and why is it no-one wants to come right out and say "someone somewhere is lying" because there cannot be both high winds, shifting of dust/sand and no erosion. Even wheat flour blown at 50MPH over millions of years would erode rocks. Thats how rock-tumblers polish their stones on Earth, with finer and finer 'sand'.

originally posted by: qmantoo

Smurfy, I would love the winds to be either strong enough to erode or not strong enough to erode. Either way I can point to (to me) weird occurrances if either of these are true. Of course it might be just that I dont understand the complexities of the conditions there, however I would have thought there would be consistency from NASA etc.


Completely off topic, but I would love to see a recent satellite best-resolution view of Spirit in its last resting place. Previous rovers appeared to have been dismantled (probably blown apart due to the high winds!)

Put it this way, The Mars wind has force enough to do erosion...on Mars, but even there as it is at present, it is still very weak. I don't know that anyone is saying there is no erosion.
The other query about other rovers, as far as I know, Opportunity is still at work.

originally posted by: Silcone Synapse
a reply to: Lady_Tuatha


Pics 5 and 6 in the OP show a bank of 6 cameras/sensors-note the glass covers are dust free,although surrounded by dust.

I am not sure,but I think that may mean they use ultrasonic pulses to rid any dust from the lens/sensors-Digital SLR cameras have a similar feature,in which ultrasonics are pulsed through the CCD,in order to remove any particles of dust.
They must be keeping those lens/sensors clean somehow.

You know, that's very striking in a way. Curiosity has Atomic power, while Opportunity has Solar, and they are both still at it. I know it's two different aspects to talk about, but both involve dusting. In the case of Opportunity, NASA supposed that dust on the solar panels might have been a problem eventually, but it seems that rover is running still at somewhere near full power, and while it does accumulate dust on the solar panels, there seems to be some cleansing going on in a natural way from the night time frost once there is daybreak, and there is a run off, keeping the Solar panels clear, and they can measure the clearness.

Very cool to see it like this. I love comparison pictures over time. The Titanic was also a good one. Thanks OP for sharing your find.

It really seems to be holding about as well as my 4 wheeler here on Earth.

originally posted by: Blue Shift

And I will once again express my ongoing surprise at how many rocks on Mars appear jagged and unweathered, as even small winds carrying tiny grains (and the occasional global dust storm) will wear rocks nice and smooth after a few thousand years. Which leads me to think that there are some pretty powerful and active forces churning the surface up either occasionally or periodically.

There could be Mars quakes and Vulcanism. Curiosity doesn't have seismic detectors, but it reports daily on atmospheric density in the locale, so if Curiosity was buffeted say when static, they might just go with something like a 'quake, and not likely wind. There is no sign of that so far in either case unless they are covering up like for instance, Curiosity is in Arizona.
However Curiosity V2 will have seismic detectors.

It would be interesting to see if wind erosion is in relation to gravity as well.

With our thick atmosphere and high gravity, a particle of "dust" would have a reasonable erosion affect.

As they say with less dense atmosphere, the wind is not as strong, and with a lighter gravity, the weight (force) of a particle would be less too....I would think. Mass may be the same, but weight, therefore erosive impact, would be less I guess. May be wrong tho.
And there isnt too much liquid water either.....now anyway.

The rover would probably last much longer than it would, unexposed, on Earth.

originally posted by: gort51
It would be interesting to see if wind erosion is in relation to gravity as well.

With our thick atmosphere and high gravity, a particle of "dust" would have a reasonable erosion affect.

As they say with less dense atmosphere, the wind is not as strong, and with a lighter gravity, the weight (force) of a particle would be less too....I would think. Mass may be the same, but weight, therefore erosive impact, would be less I guess. May be wrong tho.
And there isnt too much liquid water either.....now anyway.

This deals with what you are saying, where the kinetic energy of the wind..as a force impactor on a object needs to be calculated as dependent on the velocity of the wind...etc...faint!

From Mary Urquhart, also 1997;
Actually, the density of the Mars atmosphere is only about 1/100 of the
Earth's. How a wind "feels" to an object in its path is dependent on the
density of the wind (the number of molecules per unit volume) and the

The momentum of the wind is the density (really the mass of the molecules in
the wind added together) times the velocity of the wind. So, an object on
Mars will encounter wind with 1/100 the momentum of wind on the Earth
traveling at the same velocity. That means the wind on Mars has to be
traveling a 100 times faster than the wind on Earth to have the same
momentum.
However, the kinetic energy content of the wind is dependent on the velocity
of the wind squared (or K.E. = (M x V x V)/2 ), so the wind on Mars only has
to travel about 10 times as fast to make up for the difference in density.
Mary Urquhart
Laboratory for Atmospheric and Space Physics
University of Colorado at Boulder.