The West Valley Route Options

[alan]

Some views of the potential Tarturi
from sol 758

and from sol 1374

[alan]

And a look ahead to the other side of West Valley and the path to von Braun


ETA: from sol 1350

[RoverDriver]

...
Tartarus Warning!!!! Maybe not, but this is going to present some interesting times for the MER Precision Driving Team.

Yep. I think the 20+ meter drives are a thing of the past. We'll see where and how far we can go now. Keep your eyes peeled.

Paolo

[Shaka]

...peeled and perspicacious, Paolo!
Unless we spot some dusty puddles in our path, I'd say we should just brush the edge of the HP talus exposures with our 'easterly wheels' (starboard side?). There the fine sediments should be shallowest - least likely to swallow us up - and keep us close to the HP strata we want to study. Of course, it's possible that some PIs will want to plow up the deep sand in the middle of West Valley looking for 'delicious siliceous deposits'. (De gustibus non disputandum est.)
But if we get bogged down, we should all be allowed to say "We told you so!"

[Astro0]

Marked in red, a best estimate of the Sol1861 rover position. Any takers?


Astro0

[Geert]

Keep your eyes peeled.

This is about the closest I can get while still convincing myself that I'm not only tracking garbage.

Above image is made by combining 2 HiRISE images (to as much as possible eliminate shadows and garbage) and then asking the computer to mark area's with similar average relative brightness and variance. Resolution is 12.5 cm/pixel and grid is 3 meters.

Note the colors do NOT have any meaning in themselves, they only mark area's which 'look' the same to the software, in other words colors mark areas which have the same average brightness and the same variance. Keep in mind that slopes will also result in differences in brightness, so an east-facing slope will often get a different color from a west-facing slope even if it is in fact the same 'sand'.

I think what we can say is that we have been driving on 'brown' and 'dark purple' without getting stuck, so that's probably okay, but there is some 'lightblue' ahead which we have never driven on with only a small strip of 'okay' brown passage. "Unknown" colors MIGHT be dangerous or at least require attention.



On a scale of 25 cm/pix but using the same color-set this is the remaining area from West Valley to VB/GD, once again colors are only used to mark terrain with the same average brightness and variance but have no meaning in themselves. In order to mark colors as 'dangerous' or 'safe' I would have to check all measured terrain with terrain where Spirit has been driving previously and them mark it with a value-indicator (more or less what Mike has been doing for Oppy on Meridiani) and even then you can only state something about 'known' terrain.

[jamescanvin]

James, did you do a color 3D version of the West Valley Pan, sols 1366-1369?

No, just the 2D colour: http://www.nivnac.co.uk/mer/index.php/a1366

I'll try and do a 3D version as we are heading back that way. It was only taken using one filter with the right pancam so colour 3D will be tough, but at least it is R1 (blue) so it's not impossible.

[jamescanvin]

Geert, I'm not sure that analysis shows meaningful differences in terrain. You seem to have ended up with a similar range of colours for both the terrain on top of HP and that surrounding it - something we know from ground truth to not be the case.

[djellison]

Sorry Geert - I'm with James. Your analysis doesn't achieve anything when compared to ground-truth.

Doug

[Ant103]

Distant dust devils captured on Sol 1856

Attached thumbnail(s)

 

[Geert]

Sorry Geert - I'm with James. Your analysis doesn't achieve anything when compared to ground-truth.

I was afraid of that myself also already, as mentioned earlier its almost impossible to do anything meaningful from orbital images at such small ranges, you end up chasing ghosts ;-)

The only truth will need to come from the eyes of the rover itself.

[Stu]

Phew! It's not just me then! A few times I've looked at them and thought "But if that colour is meant to be rocky, how come it doesn't look rocky on the pictures?" then thought maybe I was just being dumb and missing something slap-across-the-face obvious or just not interpreting the images correctly. But for some time now I've been thinking that - and I mean absolutely no disrespect here to the people who spend so much time working so hard on making them - these "terrain mapping" images are now a little bit irrelevent, especially when it's stated that the colours don't actually represent any ground truth.

[MahFL]

I think I've found sol 743 weels tracks
Visible for a few meters before and after these two black rocks in the first 1/4 from the back of the picture a little bit on the right from the center. Agree?

By "back" do you mean bottem ? if so then thats the front ! right ?....lol. Took me a while to spot them, as I was looking in the wrong place.

[Geert]

these "terrain mapping" images are now a little bit irrelevent, especially when it's stated that the colours don't actually represent any ground truth.

Colors can only mean one position has the same relative brightness and the same variance as an other position with the same color, there is absolutely no way they can say anything more be course that information simply is not in the HiRISE data. CRISM and THEMIS tell you a LOT more about the surface, but both have a resolution which is far and far less then what we need here, so you can't use them in this case. I gave it a try to see if there was any way we could get any information from HiRISE when working on this small scale but I was already very skeptical about it, it was a nice exercise in chasing ghosts

[Stu]

it was a nice exercise in chasing ghosts

It was definitely worth a try, yep! Not taking anything away from the effort or intentions. I think we can leave those particular ghosts alone now tho, and just enjoy the spectacular real views

Speaking of which, hoping we're soon going to get a second look at my very favourite martian rock, McKay (lower right), last seen around Sol 747...