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After Victoria..., .. what next?
nprev
post Feb 13 2008, 12:55 PM
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Shaka, thanks for the vote of confidence, but Doug's got it right. We've got differential circumstances between Spirit & Oppy, and even assuming just a single possible failure mode (open wheel motor winding) the system can't really be described in a linear...i.e., predictive...fashion any more; we're deep into unknown territory here, and there are a <clink>load of variables to consider; any model would yield a portfolio of results that would be all over the place.

After all, the MERs have already far outlived their design lifetimes; they could last five more minutes or five more years (though I'm betting on the latter, and still think that statues of the design team members should be erected at all engineering schools... smile.gif )


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dvandorn
post Feb 13 2008, 04:16 PM
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Well... we're still in predictive territory, in that we seem to be able to make the definitive statement "increased power draw means the wheel *will* fail at some point in the future." In other words, what we *can* do is infer from Spirit's example that the behavior we're seeing on Oppy means we've begun a failure mode; what you're saying we *can't* do is apply the Spirit example any further than that, to determine how that failure mode will play out in terms of time and use.

I understand your points, Doug and Nick. I will also say that they remind me of a basic argument that occurred during Apollo, the grand debate as to whether you could ever test flight hardware enough to ever determine its failure modes. There was one camp that believed it was insane to commit humans to systems that hadn't been tested hundreds of times, and another (the winning camp) that said you test to ensure the design is correct, but that there is no way to economically test every system enough times to get enough data points to make accurate failure mode predictions based solely on your test results. That second camp, the ones who invented and championed the "all-up" testing philosophy, understood the physics of their systems so well that, in some cases, they could use *single* data points to accurately define and predict failure modes in all sorts of booster and spacecraft systems.

I've seen many, many examples of accurate failure mode predictions based on only a few data points (but also based on a firm understanding of the physics of the situation). They ought to bring Mad Don Arabian out of retirement -- he used to do this kind of thing six times before breakfast... *grin*...

-the other Doug


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Stu
post Feb 13 2008, 05:19 PM
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Okay, let's look at it from another angle. The Great Genie of Mars pops up from beneath those rippled dust dunes on the floor of Victoria, spins over to Oppy, and with a huge flash and a manic laugh magically grants Oppy another year of "life", guaranteeing that her wheels or steering won't fail, her computers won't crash, her cameras won't dim and die, etc. She's in fine fettle.

You now know you can get to Ithaca...

...but is it worth it? Is there anything to see, or do, once you get there? I can't see any outcrops there, I can't see much at all. The first landforms she'd come up against would be those mountains on the western edge. She's not climbing those, is she? If she heads north, skirting around the mountains and into the crater, what's there?

So, it comes down to a simple choice I feel, if you push these engineering and lifespan issues aside. Would it be scientifically useful and rewarding to trek to Ithaca, even if Oppy could? Is Ithaca a more attractive scientific target than the opposite side of Victoria, where we have, if you recall, such as yet unseen and unexplored attractions as Sofi's Crater, Soup Dragon, numerous ridges and slump features, etc?

Personally, I'd much rather she finishes up at Gilbert, comes out, and drives on around the edge, continuing and completing her survey of Victoria Crater, than head off towards a destination that looks - if I dare use the word I always hear in my head whenever I look at a photo of it - boring.

And if I was Steve S or Jim B or any of the team, if I started to think that Oppy was nearing the end of her days I'd much rather drive her down to the crater floor and becalm her in those dust dunes, where she could end her days with dignity, taking beautiful panoramas, at different times of the day, showing the outcrops and cliffs surrounding and looming over her, beautiful images that would crown the Opportunity mission appropriately, than just monitor her dragging herself south, sol after sol, until one of those sols was eventually her last and she ground to a halt out in the middle of nowhere, with nothing to do except look at the clouds scudding overhead and the impossibly faraway horizons all around her.


smile.gif


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centsworth_II
post Feb 13 2008, 05:31 PM
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I say when her mobile days are over, park her in the dark streaks
on the north rim. A couple years of Micro and Pan Cam studies should
settle the deposition vs clean sweep debate. laugh.gif

edit: Alternatively, park her on the "Beacon". A fitting memorial station
and a good lookout for a one-year time lapse, 360 degree movie of the
area's cloud and dust devil action.

This post has been edited by centsworth_II: Feb 13 2008, 05:40 PM
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ustrax
post Feb 13 2008, 05:55 PM
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QUOTE (Stu @ Feb 13 2008, 05:19 PM) *
with nothing to do except look at the clouds scudding overhead and the impossibly faraway horizons all around her.


But, at least, she would have tried.


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fredk
post Feb 13 2008, 06:12 PM
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I'd've thought there's probably plenty of exposed bedrock in those Ithaca rim hills, and surely climbable routes, at least before a wheel failure. And the interior appears to have plenty of "etched terrain", which presumably means exposed bedrock. Remember that's one big crater, and we don't have very high resolution images of it yet.

But I'm not convinced that Ithaca is a viable target. As I argued before, given the difficulties of maneuvering dunes, even with hirise imagery, I'd vote for taking the quickest route back to the smooth, flat "tarmac" to our north/northeast. Once there, there are many potential target craters in various stages of erosion (some looking very fresh), and the distances should pose no serious obstacle, perhaps even with a wheel failure. This would be our best bet at learning about the horizontal variation in the geology. And if the imagery supports it, there's still the possibility of following the tarmac all the way to the north rim of Ithaca.

Stu, I'm surprized by your suggestion of ending Oppy's days mired in the sand inside Victoria. If she were to come to rest at Victoria, I've long had the secret wish that it be atop the Beacon. From the highest point for kilometres around, she could monitor most of the crater and all of the surrounding plains.

And hikers doing the Oppy trail in the 23rd century may be guided towards Victoria by not just the Beacon, but, if they're lucky, by a glint of sunlight reflecting off our little friend, the Sentinel of Victoria crater.
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Stu
post Feb 13 2008, 06:12 PM
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There's no glory in trying for something that's not worth the sacrifice my friend.

Believe me, if Ithaca was a bigger version of Victoria, with crumbling outcrops, debris fields, dark streaks, ridges and ledges, I'd be waving a "Go Oppy!" banner too. It would be worth striking out for because, once we got there, there'd be sights to see, rocks to study, laters to investigate and panoramas to take. But look at it. There's Nothing There. It's an outline of a crater, an ex-crater, not really a crater at all.

A far nobler goal for Oppy - IMO - would be to circumnavigate VC before she rolled to a halt. Then we would have a great overview of the area, its environment, and geology. That far side of Victoria looks fascinating, doesn't it? Who isn't intrigued to know what the view would be from over there? Who isn't curious to look down on Soup Dragon and see those weird rocks from above? Who doesn't want to roll up to Sofi Crater and see how its formation scuffed up the rocks on the edge of VC itself?

Ithaca isn't a Promised Land it's just Somewhere Else To Go. Victoria has secrets to reveal yet, I'm sure. And we're already there.

Still, Steve told you you might be surprised where Oppy is heading, so we'll have to wait and see! smile.gif


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Stu
post Feb 13 2008, 06:16 PM
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QUOTE (fredk @ Feb 13 2008, 06:12 PM) *
Stu, I'm surprized by your suggestion of ending Oppy's days mired in the sand inside Victoria.


Sorry, I meant if her demise was imminent, i.e. if she started getting creaky before she had finished exploring her current surroundings. I absolutely agree that the top of Beacon would be a fitting resting place for Oppy, and I love your closing image, it's just what I see in my mind too. smile.gif


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Nirgal
post Feb 13 2008, 06:50 PM
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QUOTE (ustrax @ Feb 13 2008, 06:55 PM) *
But, at least, she would have tried.


I'm with Ustrax on this one.

the small scale variability of the terrain encountered by the rovers thus far has been surprisingly high (remember the
sudden disapearance of the blueberris etc.)

So if Oppy makes use of her remaining bonus life time to drive as far as she can onwards to new horizons then we
have a small but realistic chance of discovering entirely new and spectacular scientific findings waiting for us somewhere
out in the plains bewteen the dunes ...

Ponder this chance for entirely new discoveries (even if as low as, say 10 per cent)
against another couple of hunderd sols of in-place routine observations ....

So in the beginning of the mission we would clearly opt for the second alternative, avoiding unnecessary risk and make the most scientifc use per sol out of the expensive hardware

... but now, on bonus time, 10 times beyond any initial mission expectations... nothing to lose any more ... only to win smile.gif








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ustrax
post Feb 13 2008, 07:29 PM
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QUOTE (fredk @ Feb 13 2008, 06:12 PM) *
Stu, I'm surprized by your suggestion of ending Oppy's days mired in the sand inside Victoria.


I am surprised by the fact we are establishing already a resting place to a rover that came all the way from Earth bumping into a small crater in Meridiani, then, enduring, reached a bigger one, and, victoriously, managed to, in spite of all the adversities, reach where we are now.
I'm all for the deep study of Victoria, but I'm eagering for the open spaces again, for the horizons gaining a contour.
I'm all for a new destiny, that does not mean necessarily Ithaca but others on the way to it.
And Stu...nothing to see? Have you see those peaks stretching from Oppy's line of sight at Victoria? That would be the same to say, when Spirit reached Gusev, that those hills weren't worthy, or unreachable as they were supposed to be.
Of course people have different ways of thinking, the Beacon image is quite romantic, but I'm more "Onward!" than romantic...I'm more of the kind to cross the Adamastor's cape and turn it into a Good Hope one than to sail on Africa's west coast's calm seas...I want to make it to India all the way, even if I do die trying so.
Magellan, who we honour at Victoria died pursuing is goal, never made it to Sevilla.
I would rather feel, when I become an elder man, with eyes wide open looking at the ceiling, that a certain rover tried the impossible and, bravely, fighting against age and an alien planet, ceased its journey exactly there, as you described it, among no and where. That no and where has a whole different meaning for me, it means that we went beyond what was expected, we have reached never seen lands, we have honoured our nature: To go Onward, against all odds.

I am not ready to sentence Opportunity to end its days at Victoria.

I want to see more, I want to rove more, I want to learn more, here I'll make mine Nirgal's words...new and spectacular scientific findings waiting for us somewhere out in the plains between the dunes...

The dunes...Opportunity's sea...if it has to be that way may our descendents find the brave wreckage of a mythic vessel that Tried to challenge the Gods...Prometheus comes to mind...

And all the hypothetical path towards Ithaca may, itself, be full of amazement and knowledge...we have several Victoria-sized craters on the way...we may increase our navigational skills for missions to come...we may learn a lot more about Meridiani...we may beat the horizon...

I am for the Ithaca dream, even if we wake up from it before its over.
I am for the Beyond. May we supply ourselves here, at Victoria, with all we need for the journey, the journey that I hope to be "a long one, full of adventure, full of discovery."


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algorimancer
post Feb 13 2008, 07:48 PM
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To address the "nothing to see, so why bother" - I'll quote one of my older (May 2007) posts on the topic:

"...Boring? I think not as bad as prior to Vicky, and the destination is already visible. There will be various outcrops and craters along the way, and lot's of entertainment in projecting where Oppy will go next. Plus Oppy ought to be moving quickly enough to guarantee some regular changes in scenery.

As to scientific value, this takes us into an entirely new geological realm, not only the Ithaca rim peaks themselves, but the interior of Ithaca as well - which the MOLA maps indicate is substantially (hundreds of meters, as I recall) lower than than Vicky, and thus having the potential of having once contained standing water. Taking Oppy in any other direction would just see more of the same fractured/layered evaporite - talk about boring..."

Likewise, with regard to navigability, I once (June 2007) looked into this in rather more depth than I have time for now:

"...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, cool.gif 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 smile.gif

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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dvandorn
post Feb 14 2008, 04:27 AM
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QUOTE (fredk @ Feb 13 2008, 12:12 PM) *
I'd've thought there's probably plenty of exposed bedrock in those Ithaca rim hills, and surely climbable routes, at least before a wheel failure. And the interior appears to have plenty of "etched terrain", which presumably means exposed bedrock. Remember that's one big crater, and we don't have very high resolution images of it yet.

But I'm not convinced that Ithaca is a viable target. As I argued before, given the difficulties of maneuvering dunes, even with hirise imagery, I'd vote for taking the quickest route back to the smooth, flat "tarmac" to our north/northeast. Once there, there are many potential target craters in various stages of erosion (some looking very fresh), and the distances should pose no serious obstacle, perhaps even with a wheel failure. This would be our best bet at learning about the horizontal variation in the geology. And if the imagery supports it, there's still the possibility of following the tarmac all the way to the north rim of Ithaca.

I can't agree with you more, Fred. In fact, there is a post in here (likely in this very thread) in which I argue fairly strenuously for heading north-northeast and visiting a set of three craters that are relatively close to each other, but which have very different apparent morphologies. (Being the imaginative fool that I am, I named them A, B and C, if I recall...)

As for Ithaca / Big Crater, this thing looks big enough to have been formed at the end of the LHB. It has undoubtedly raised a lot of the strata that underlies the evaporite paving of Meridiani Planum into its rim hills, which would provide incalculable insight into the history of the region. But -- and it's a big but -- that material will have been heavily shocked and jumbled, covered by subsequent deposition, and difficult to find windows into.

Ithaca might be a very good target for a brand-new rover that lands within a km of its rim hills, but I doubt Oppy, even if she could get there, will have enough left in the tank to scrabble around and do a good job of characterizing the geology of the place.

So, my vote would be to exit the area (if that's what we feel we need to do) on a north-northeast vector, find the flattest tarmac we can, and investigate as many different crater morphologies as we can before she becomes a stationary lander mission.

-the other Doug


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AndyG
post Feb 14 2008, 10:55 AM
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It may not be exciting, it may not be visionary, nor will it fire our romantic spirit, but post-Victoria, if Oppy's moving, surely the most info-per-metre route will be to backtrack at least some of the way she's been. We know the way and the terrain.

The Meridiani science to date has largely been snapshots of the planet. There's little to relate how Mars looks now to how Mars changes over a month, a year, two years. What processes occur over timespans we have no experience of? What state are old tracks in? Did the duststorm alter sites previously visited? On what scales?

Real world data of Mars' dynamism, and practical engineering data relating to the development of future, better rovers must be more worthwhile than some trek into the unknown with a certainly unattainable goal - or the parking of a still-mobile rover for little more than symbolic purposes.

Andy
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ustrax
post Feb 14 2008, 02:49 PM
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How could have I missed this post?... blink.gif
Thanks for those links marswiggles! smile.gif

While there's no HiRise images we have almost all the terrain covered, what permits us to wildly, wildly speculate about possible routes and timelines...here's my take on reaching Ithaca in 16 months...OK, I'm will to push that into 2 years, not more than that... tongue.gif

Attached Image


Too unreal?...


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djellison
post Feb 14 2008, 03:01 PM
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Endurance to Victoria was a sprint. It had technical halts, but so would the drive to Ithaca. It had very very few science stops of any significance. Over long distances of mixed terrain - that's as good as it gets.

It took 22 months to reach Victoria. There is no reason to suggest a more rapid rate of progress could be made on the way to Ithaca. 40-50 months (or roughly 3 to 4 years) is far more realistic. Give the likelihood of one or more serious mechanical failures on the way, a conservative estimate could be at least double that.

That route in particular isn't great. South East isn't really a nice option. NE is far more navigable.

Doug
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