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Endeavour Drive - Drivability analysis
Stu
post Sep 21 2008, 11:58 AM
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I've found Endeavour on some THEMIS images...

http://themis-data.asu.edu/img/browse/I10685008

http://themis-data.asu.edu/img/browse/I15290007

... and just wondering, does the ground drop away into a kind of shallow basin at the top there?

Attached Image


Could that be the ghostly rim of an older crater, obliterated by the formation of Endeavour?





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SFJCody
post Sep 21 2008, 12:05 PM
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QUOTE (Tesheiner @ Sep 21 2008, 11:24 AM) *
- Drive E when moving on flat terrain
- Drive SE when moving by the dune fields. I'm here assuming these fields follow the general direction as the ones on the path from Erebus to Victoria.


Agreed. So, for safety puposes I think the rover should drive CCW around Victoria keeping the same distance as it did when travelling CCW to get back to Duck Bay when the initial recon was over. Once on the eastern side drive due east across the annulus until the increasingly large ripples begin to become a hazard. From there SSE using a 'stair-step' approach; following the trend of the ripples and using gaps/areas where the ripples have lower crests to cut east.

Looking at this HiRISE image the ripples diminish in size in the SE corner of the frame, this looks like a good point to move east.
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Tesheiner
post Sep 21 2008, 02:41 PM
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Yeah, it's time for back-seat driving and here's yet another potential route.
It's not covering the whole way to Endeavour but only to a small Endurance-like crater mid-way between VC and Endeavour, named here "Mini-Endurance" by SFJCody. Instead of searching for a path from VC to ME I did the opposite; from Mini-Endurance to Victoria. The terrain around Mini-Endurance looks pretty easy and becomes more wavy closer to VC. I won't be afraid because, except for the part closer to VC after the annulus, the terrain is similar or smother than the one nearby Vicking and Voyager craters.
Attached Image


Here're some snapshots (HiRISE) of the waypoints and of Vicking/Voyager for comparision.
Mini-Endurance:
Attached Image

M -1:
Attached Image
, M -2:
Attached Image

M -3:
Attached Image
, M -4:
Attached Image

M -5:
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, M -6:
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Vicking & Voyager:
Attached Image

Open this page and scroll down to the Vicking panorama to have a look to the kind of terrain we are talking about.
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RoverDriver
post Sep 21 2008, 04:12 PM
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QUOTE (Tesheiner @ Sep 21 2008, 06:41 AM) *
Yeah, it's time for back-seat driving and here's yet another potential route.
It's not covering the whole way to Endeavour but only to a small Endurance-like crater mid-way between VC and Endeavour, named here "Mini-Endurance" by SFJCody. Instead of searching for a path from VC to ME I did the opposite; from Mini-Endurance to Victoria. The terrain around Mini-Endurance looks pretty easy and becomes more wavy closer to VC. I won't be afraid because, except for the part closer to VC after the annulus, the terrain is similar or smother than the one nearby Vicking and Voyager craters.


Good thinking. At this time it might be best if we concentrate on the area visible in this HiRISE image and then we will go from there. Correlating the new terrain with terrain we have driven on is exactly right. We (well, *I* do, unfortunately this is one of the the details I cannot talk about) have engineering telemetry and can determine how fast (meters per sol) we can drive. I was wondering if there was a way to automate terrain evaluation, I'm mostly worried about ripples. Maybe applying the FFT to patches of the greyscale image can tell us where the scary ripples are. Maybe some other texture filters?

I think that spending some time getting our tools ready to evaluate the new HiRISE images might be the best thing to do. It will help in the near term and it will make our life easier in the long run.

Paolo


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fredk
post Sep 21 2008, 04:18 PM
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QUOTE (RoverDriver @ Sep 21 2008, 01:54 AM) *
OK, now think what would be the easiest and safest route to Endevour if you did not have to stop for science... How far from the rim would you keep the rover? Keep in mind that a couple of stops on the rim might be requested.

Welcome, Paulo. It's a thrill to have a real driver acknowledge us noisy back-seat drivers!

Given the ease we've had so far driving on the anulus, I'd think we're basically "science-dominated", ie anywhere the science team decides to visit around the rim of Victoria should be easy to reach. There are some larger dunes on the eastern rim to keep an eye on, especially if the science team wants to do imaging from the rim (eg the "linear features" that've been discussed). Of course the less we advance the odometer the better.

As for the route to Endeavour, my post and route sketch from over a year ago was based on the principle of "avoid dunes whenever possible", and the hirise image PSP_001414_1780, and the hope that the tarmac continues east (I haven't seen hirise images further east). The "tarmac" to the NE appears to have the smallest dunes, but I agree that Tesheiner's route above (or a similar route that heads more directly east at first) looks not too bad, at least barring a wheel failure. A big question I have is what happens to our dune traversibility if we loose a wheel? Perhaps in that case you'd rather be on the tarmac to the NE.

It might appear that a "tarmac" route as I sketched would be longer than a more direct route to the SE, but tarmac means essentially straight drive segments, while dunes probably mean zig-zagging east when you can cross dunes, then south between dune crests, so the total distance may be much larger than the "crow flies" distance.

Perhaps there's going to have to be a mathematical expression for the "favorability", F, of a route. Greater total odometry would reduce F. Fewer and smaller dunes increase F. Better science en route increases F, especially since our arrival at the final destination is far from guaranteed! I would not like to try guess the form the expression for F would take, or how much weight to give the engineering versus science goals!

I wish you the best of luck as you embark on your greatest road trip yet!
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Phil Stooke
post Sep 21 2008, 04:28 PM
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I accidentally posted this in the other thread so I'll put it here too:

"Due south from Victoria is very feasible. The drifts never get as big as to the north, and after a few km they give way to surfaces nearly as smooth as the area near Endurance, but with more flat outcrops - this from the HiRISE image extending furthest south and east. So, south until the drifts disappear, and then southeast via the Endurance-like crater to the isolated hill on Endeavour's rim is very realistic.

Phil"


Looking at the way-points, the big drifts at M6 are exactly what you want to avoid, if long-distance/sol driving is the goal. The SE path from the annulus to M6 is quite bad for driving. But head due south off the southern rim of Victoria, and the N-S oriented drifts allow driving in that direction quite easily, and soon get smaller. Then the path can meander through the smaller drifts and outcrop areas quite easily until the mini-Endurance crater is reached. There the surface looks easy to drive on.

Phil


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ustrax
post Sep 21 2008, 04:32 PM
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Dear Fredk, maybe I'm missing something here but isn't your path towards Endeavour pointing in the opposite direction, NE? unsure.gif
EDITED: Forget what I've written...just reread it and saw that heading NE was precisely your point... rolleyes.gif

Stu, about an older crater I don't know but I see three beautiful ones due South...maybe we should start our campaign right now to have things ready for when Oppy finishes her work at Endeavour... laugh.gif
Attached Image

Is any of these Miyamoto?...

EDITED: No it is not... rolleyes.gif


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BrianL
post Sep 21 2008, 07:52 PM
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QUOTE (Phil Stooke @ Sep 21 2008, 11:28 AM) *
But head due south off the southern rim of Victoria, and the N-S oriented drifts allow driving in that direction quite easily, and soon get smaller.


Sorry, Phil but I can't see it. Admittedly, I don't have the big JP2 files to look at* but from the smaller images, due south just looks like a route fraught with peril. The dunes seems very large, and oriented E-W so Oppy would have to cross them. Algorimancer had that area blocked off in his post from last year's discussion. Help me see what you're seeing, Phil.

* And if someone can give me a JP2 for Dummies lesson to help me view these pictures, it would be much appreciated. smile.gif

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Tman
post Sep 21 2008, 08:35 PM
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In the HiRISE Online Image Viewer can you select an image to explore in full-resolution. They are labeled for faster find - btw. for PSP_001414_1780 what's the meaning of that "possible" - a typo?


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mhoward
post Sep 21 2008, 08:36 PM
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FWIW, I agree with Phil. When I looked at the MRO image in full resolution way back (this was months and months ago), my conclusion was to to head straight south from Victoria until the drifts diminish. I think you have to look at the full image in full resolution, and compare it to similar images of ground we've already covered, to reach any conclusions at all. Although the route south might not be easy at first, I didn't see an easier route anywhere to the east at the time. I could be wrong, of course.
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Phil Stooke
post Sep 21 2008, 09:02 PM
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Here's a comparison of textures, all at 100% from the IAS viewer provided on the HiRISE site. It's not at all useful to view the images at lower resolution.

Attached Image


The top three show places we know. At Vostok it was still possible to drive diagonally across the drifts. At Purgatory the only possible route was parallel to the crests, or zig-zagging around individual drifts, quite slowly.

Below that are various areas at the same scale as the first row. East of Victoria is a huge band of big drifts. It's not practical to try to drive eastwards through them. At low resolution it looks like the crests are E-W, but they aren't - those are a different scale of massive mounds superimposed on the drifts, like Purgatory itself.

The E-W band of outcrop shown on the low-res map linked to above is actually very bad - huge drifts cover much of it. It is not a highway leading east.

The best plan is to run south through the smaller drifts. HiRISE lets one map them out very easily, and clumps of bigger drifts can be avoided very easily. By the time we get to that mini-Endurance crater the surface is much smoother and from then on it looks easy (within the existing HiRISE coverage).

Phil


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mhoward
post Sep 21 2008, 09:06 PM
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Now that Opportunity is going that way, I hope we actually get to see the "darkened" or "scraped" terrain southeast of Mini-Endurance, mentioned here. I'm staking this out as my own "El Dorado", ustrax wink.gif

Perhaps in about a year?
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djellison
post Sep 21 2008, 09:09 PM
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http://hirise.lpl.arizona.edu/PSP_009141_1780 is probably the best for heading south

Basically - due south it awesome for about 1km
Then it sucks for 2km
Then it's OK for a km
Then it rules turning east.

Doug
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Phil Stooke
post Sep 21 2008, 09:09 PM
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I agree with mhoward, that's a great looking area. Oh boy, the fun never ends on this mission.

Phil


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Tman
post Sep 21 2008, 09:12 PM
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Shouldn't it be possible to go through that area of large ripples in "M6" and "M5"? Some outcrops and smaller ripples look comfortable to drive SE. We would have the fast directly East drive on Victoria's annulus and then drive at "M4" already in that smaller ripples.


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