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After Victoria..., .. what next?
ustrax
post May 31 2007, 08:29 AM
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QUOTE (Pando @ May 31 2007, 06:25 AM) *
...and you haven't changed a bit! biggrin.gif smile.gif


Hey Pando! smile.gif
Tradition still is what it used to be...
I don't know if I should smile or cry about it... tongue.gif

You are forgetting the final climax of those crazy crazy days... smile.gif
In spite of everything one thing is for sure, we DID get there, so I'll just keep on dreaming about Ithaca and, who knows, if some years from now you will be reminding us this posts? wink.gif

Regarding an hypothetical path after Victoria I'm also starting to agree that the road passing by the ABC craters is the most logical one, but without loosing Ithaca out of sight... smile.gif


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Edgar Alan Poe
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Stephen
post Jun 1 2007, 11:35 AM
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QUOTE (djellison @ May 30 2007, 10:03 PM) *
Stephen - have you looked at the HiRISE image to the SE of Victoria?

I find that downloading gigabyte-size files is expensive, taxes bandwidth, and probably pointless if the machine I download them to cannot usefully handle them anyway. I have however been looking at some of the smaller versions of those files which you and others have been putting up here and elsewhere.

QUOTE (djellison @ May 30 2007, 10:03 PM) *
Be bold, be brave, go exploring - I agree. Jump off a metaphorical cliff? No thanks. This is a PRICELESS asset we're talking about.

Nobody is proposing the rovers do any swan dives off any metaphorical cliffs. But at the same time you need to ask yourself whether fear of the unknown--the unknown sand trap, that is--is a good enough reason to avoid at least trying.

QUOTE (djellison @ May 30 2007, 10:03 PM) *
We can spend another two year at Victoria crater doing good science that we can get to. It's here - it's extraordinary - it's feasable.

I have no problem with Opportunity staying at Victoria and examining it inside and out. But then I doubt if you would find anyone on this forum who is saying it shouldn't.

That said, be careful with that "good science" claim. Let's face it. Mars is still largely a blank slate. The rovers could go virtually anywhere, stick an IDD in, and get good science back. Consider Spirit. It is finding good opportunities for good science through pure chance and the dragging of a non-functional wheel! A more pertinent question is whether the science obtainable at one particular site would be more useful to a rovers' goals than the science it might get by going elsewhere.

At Victoria I would agree there is certainly very good science obtainable there that Opportunity would not get, at least easily, by going elsewhere. The same however is more disputable for other places like, well...

QUOTE (djellison @ May 30 2007, 10:03 PM) *
Then - there's stuff we rushed past at Erebus - we KNOW we can get back there.

IMHO, the rovers should not go over old ground without good reason. There are good reasons for Spirit's return to Home Plate, for example, but there may well be good reasons for Opportunity to go back to Erebus, but unlike Home Plate I yet to hear what the Erebus ones are. The one you give here makes Erebus seem more like a consolation prize: the place Opportunity would be consigned to if there was nowhere else more useful for it to go.

QUOTE (djellison @ May 30 2007, 10:03 PM) *
There's exposed rock that is perhaps 2-3-4km to the SW that would be tough to get to - but it could be interesting.

Sounds OK to me. Whether it is a best destination however is another matter.

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Stephen
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Stephen
post Jun 1 2007, 11:43 AM
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QUOTE (djellison @ May 30 2007, 10:03 PM) *
Then there's this crater that's half a decade of driving away over terrain we already know to be hazardous to the MER desgn.

Careful! Don't confuse what you KNOW with what you SUPPOSE. You no more KNOW that that terrain is "hazardous to the MER design" than you knew that there were dunes hazardous to that same design on Opportunity's route between Endurance and Victoria.

QUOTE (djellison @ May 30 2007, 10:03 PM) *
I thought Victoria was a brave option - but appropriately so - a 50/50 shot that was worth doing for the science it might offer. There was nothing left to do at Endurance - it was the best option available given the data available.

Was it?

I do not recall there was ever much discussion about prospects in the other three directions--north, east, or west beyond Eagle. Presumably they were all too flat and uninteresting--no large craters--compared to the much closer prospects to the south.

QUOTE (djellison @ May 30 2007, 10:03 PM) *
I'm not saying wrap the thing in bubble wrap...I'm saying exercise sensibility - that's all.

Which is part of the reason I object to going back to Erebus without good reason. Spirit and Opportunity have unknown but obviously finite lifespans left. Fear of large sand dunes and other putative perils may be reason enough for avoiding particular routes. They are not good reasons (IMHO) for not trying at all, much less a good reason for squandering part of the dwindling life span of a resource you claim to find so priceless by sending it over old ground for fear of sending it elsewhere.

Opportunity is more likely to make useful discoveries by going to places it hasn't yet been to than by trying to fill the blanks in by going back to places it has already visited. That could be going east or SE towards Ithaca or it could be going SW towards that exposed rock you mentioned. I suspend judgment as to which is the better pending further data.
***

I'll just conclude this with a more general observation.

It seems to me those HiRISE images are a mixed blessing. No offence, but the sight of those dunes appears to have spooked you, to the point that you seem to be treating Opportunity, at least in this matter, as if it were a kind of surrogate human being: you are so in fear of its losing its mechanical life that you are balking at sending even remotely near the supposed peril.

That in turn arguably negates one of the prime advantages unmanned robotic explorers have over the human sort: their ability to venture into places too dangerous for any human to go. If we humans are going to balk at the idea of sending unmanned robotic explorers into even mildly difficult places--ie places it can always retreat from it the going gets too tough--then how are we ever going to gather up the courage to send them into the kinds of places that may well hold REAL perils, like scaling the cliff walls of Mariner Valley or diving into the stygian deeps of the putative ocean beneath the ice of Europa?

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Stephen
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djellison
post Jun 1 2007, 12:58 PM
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QUOTE (Stephen @ Jun 1 2007, 12:43 PM) *
Careful! Don't confuse what you KNOW with what you SUPPOSE. You no more KNOW that that terrain is "hazardous to the MER design" than you knew that there were dunes hazardous to that same design on Opportunity's route between Endurance and Victoria.


We didn't know what the terrain was like from Endurance to Victoria. We had a MOC image which showed this etched terrain - we didn't know what it was like. We didnt know if we were going to get through it. There was nothing else for miles and miles - so there was nothing to be lost by trying. Ignorance was bliss.

Now - we have the information from HiRISE and the ability to compare all the terrain of that huge traverse across Meridiani with surface imagery. We can actually see. There is no supposition involved whatsoever. We KNOW that the dunes around the Purgatory area are hazardous to the MER design. We know that. We can now see dunes that are bigger than that - vast swathes of them - ones that we would struggle to find a route around or through. Thus we KNOW that the terrain South of Victoria is more hazardous than the terrain we crossed to get to Victoria - we can see it - we can see the patterns in HiRISE imagery - and it's the same patterns we saw on the north edge of Erebus - a large dune field that we took a HUGE circumnavigation to get around.

People having been drawing dotted lines on 12m/pixel imagery going south of Victoria. That's meaningless. Yes - Ithaca is a good target. But going South of Victoria isn't. If this vehicle can do another 20-30k - if it can do another 5, 6, 7 years - maybe we'll get to Ithaca...but we sure as hell wont make it if we point SE and gun it. Your human analogy doesn't work - a human could walk it quite easily - these vehicles do not have the abilities of a Human. This wouldn't be hazardous to humans (any more than the act of walking on Mars is going to be inherantly hazardous ) - a human could walk this stuff without thinking.

There was good science at Erebus that we shot straight past - the best exposed festoons we've ever seen. Good science is a good reason. Erebus hasn't been mentioned just for a laugh - it's been mentioned because it was interesting.

This isn't about 'claiming' Opportunity is a priceless asset. It is. Fact. The science team think so, the engineering team think so. I think it would be a waste of that asset to send it into terrain that - given the data we have now - would be a navigation dead end. It's not about avoiding peril - anyone who has been here for the duration knows what Peril means:

http://marsrovers.jpl.nasa.gov/gallery/all...09P1214L0M1.JPG

What's the problem driving over old ground? We're driving over old ground right now - back around Victoria - to get to good science we've already driven past at Duck Bay. Driving back to Erebus would not be that different. Spirit's doing it - back to Home Plate for science, back to Larrys Lookout two years ago. Turning around to re-visit something interesting that you couldn't give your full attention to is not a crime. Pointing at massive dune fields and putting to the foot to the floor is.

Is there not a contradiction in saying that their lifespan is finite - so let's spend 5 years driving South East through dune fields?

Again and again I've said we need more data before making a final decision - fighting and arguing about it now is premature - we're all jumping the gun. Perhaps we can make a solid case for a single HiRISE observation to answer this and submit it to HiROC - see if they'll oblige?

Doug
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gpurcell
post Jun 1 2007, 01:40 PM
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The rover spent a heck of a lot of time getting to Victoria. In the absence of a new target at an easily attainable distance, it doesn't make any sense to me to leave the crater until the potential science there is exhausted. For what? More endless Sols over a trackless dune field? And in return, we'll sacrifice many sols of in-depth analysis of the layered rock of Victoria from inside the craters?
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djellison
post Jun 1 2007, 02:10 PM
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I agree on that one - there's years of stuff here at Victoria to study yet.

Doug
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Guest_Edward Schmitz_*
post Jun 1 2007, 04:50 PM
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QUOTE (gpurcell @ Jun 1 2007, 06:40 AM) *
The rover spent a heck of a lot of time getting to Victoria. In the absence of a new target at an easily attainable distance, it doesn't make any sense to me to leave the crater until the potential science there is exhausted. For what? More endless Sols over a trackless dune field? And in return, we'll sacrifice many sols of in-depth analysis of the layered rock of Victoria from inside the craters?

This whole topic is about when the science is EXHAUSTED. The question is, what do we do then? Which direction - what targets?
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djellison
post Jun 1 2007, 04:55 PM
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But thinking about afterwards means you have to consider the in-between. Might we wear out the RAT at Victoria - or even have a wheel failure while inside. If we spend 2 months inside - then plan that invokes timelines of a couple of years might make sense. If we spend 2 years inside - then might a further 2 - 3 - 4 year plan be just too much.

Doug
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ustrax
post Jun 1 2007, 07:37 PM
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QUOTE (djellison @ Jun 1 2007, 05:55 PM) *
If we spend 2 years inside - then might a further 2 - 3 - 4 year plan be just too much.


There's always another destiny... tongue.gif


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"Ride, boldly ride," The shade replied, "If you seek for Eldorado!"
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djellison
post Jun 1 2007, 08:00 PM
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Actually - on another forum someone suggested that Opportunity start driving north to watch Phoenix land. I responded jokingly that that would be great if only it were in any way possible, feasable etc etc....only to discover he was serious.

ph34r.gif

Doug
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algorimancer
post Jun 1 2007, 08:33 PM
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Getting back to the question of whether the region between Victoria and Ithaca is traversable... I just spent some time measuring dune sizes in areas where Opportunity was able to A) Traverse irrespective of dune direction (for example, a point midway between Endurance and Purgatory, B) Traverse between dunes with care (for example, a point midway between Purgatory and Eagle), and C) Not traverse (Purgatory 1 & 2, or crossing dunes between them). I then spot-checked the HiRISE image to the south and east of Victoria and compared. Not surprisingly, there is a big non-traversable region to the east of Vicky, and another rather far towards the south, but much (most) of the remainder of the region falls in the traversable realm, either resembling the vicinity of Eagle crater (scattered dunes over open stretches of evaporite) or relatively small dunes which Oppy can just roll over without worrying about getting stuck, with the occasional exceptional big dune scattered about which would be easy to navigate around. In other words, it may be far more easily traversable than our earlier cynically optimistic assumptions. When I compare this "ground truth" with the Themis day/night infrared images it looks to me like there may be a nearly direct route between Victoria and the western rim of Ithaca, much of which can be covered in hundreds of meter safe drives. I'm feeling cautiously optimistic :)

To get a sense of this, use the fully-zoomed-in HiRISE image viewer to capture a view of the dunes (at the same scale) mentioned in A & B above, then scan around in the image viewer and compare with the captured images. The terrain gets progressively easier to navigate as you move to the southeast.
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fredk
post Jun 2 2007, 05:07 PM
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That's good to hear, algorimancer! We really have to remember that we haven't done any dune driving with the benefit of Hirise yet.
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FIN Mars
post Jun 3 2007, 07:50 PM
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QUOTE (algorimancer @ May 30 2007, 04:20 PM) *
The HiRISE coverage is insufficient to map the complete route in detail, but there's enough to show that Oppy can make it to the edge of coverage without too much difficulty, particularly factoring in the new nav software. As ustrax pointed out earlier,

http://marsoweb.nas.nasa.gov/HiRISE/hirise...SP_001414_1780/
EXCESS QUOTING REMOVED

great maps, but what about spirit?
I didn't found spirit's landing site HiRISE maps from here > http://marsoweb.nas.nasa.gov/HiRISE/hirise_images/

sad.gif
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stevesliva
post Jun 4 2007, 03:15 AM
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What is to the north of Endurance? If we retrace the path to some extent, what lies farther north?
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edstrick
post Jun 4 2007, 06:29 AM
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What's north of Endurance is one or two of those "dimple" craters, with a white ring <in b&w pic> of sulfate rock surrounding a progressively downward curving slope that then "un-curves" to a flattish floor often with a patch of dunes in it.

My take on all these is that they were relatively fresh craters that were formed BEFORE the sulfate rock that now covers them. They seem to have had a level fill of unknown material, wiere capped with the sulfate rock, and then when the water went away, the fill material compressed and the caprock dimpled downward.
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