Am I missing something? Did we not come all this way for the deepest ever look into the stratigraphy of Mars, and are we not at present barely below the pre-Victoria ground surface? I can only guess it's too dangrous to go further in. Well if it is time to exit again then for my money the most interesting target in the vicinity is - Victoria Crater. Anyone for a rim traverse in the opposite direction?

There's hopefully another few metres to go 'in' yet. Then a few weeks, I would expect, of study there. Then another few weeks of getting a little closer to the cape, get higher res shots there, and then out.

Thereafter? We've got to turn left, we already went right

The only thing that can be reasonably expected for Opportunity beyond Victoria if she were to leave is a gradual crawl into oblivion. The exploration motive that would push for a drive back out into the Meridiani wastes has some emotional appeal but I can't see that anyone who was actually in charge of such a multi-million dollar explorer could decide to waste it on such a pointless exercise.

If the team have decided that the current location has been exhausted then I'm with ngunn - continue on along the counterclockwise path and find something else to photograph, poke and analyse to the best of her ability.

Possibly I'm reading too much into Steve's comments. They might very well have additional work at, but out of, the crater in the works. Sure sounds like they are planning to move on in the TPS update:

Opportunity meanwhile, will be wrapping up the Victoria campaign and roving onward, but where exactly has not been determined. "The issue is how long do we dare stay inside Victoria Crater? At what point do we decide it's time to get out on the plains and do something new?" said Squyres. "The rover is doing great and is in great health, but if we lose a wheel, it's going to be tough getting out." There is no reason to suspect there is anything wrong with Opportunity's wheels. "But the characteristics of some of these failures is you don't see them coming. We're pushing these rovers awful hard." Opportunity's next major destination awaits a decision the MER team will probably make soon.

Brian

Potential targets for after Victoria that have been mentioned in the past include "cobbles" out on the plains and ancient eroded craters like Erebus (I think it was the "festoons" that interested them most about Erebus).

It might seem that the parts of the rim we haven't explored yet would be obvious targets, but the real question to ask is what is the potential scientific value of targets. I've had the impression that the results so far at Victoria haven't been too remarkable scientifically (but of course stunning visually!). Squyres etal must decide whether there's potentially much worthwhile to be gained from exploring the rest of the rim and entering Victoria elsewhere, to get some sense of the lateral variability of the layers in this region, or if the potential returns are greater out on the plains. As far as more time inside Victoria, apart from the question of traversability they seem to be quite concerned about the possibility of wheel failure trapping the rover.

Would descending deeper into Victoria affect the amount of sunlight it's getting?

Actually there was a mention of the right front wheel drawing excess current in one of Emily's rover updates

http://www.planetary.org/news/2007/0630_Ma...ate_Spirit.html

No more than if you took the shades off.

Seriously, not much at all, as long as you stayed well away from the cliffs. As you move in, the sun would be blocked just near sunrise and sunset, when the sunlight is hitting the arrays at a very shallow angle and so you're getting very little power anyway.

And, since your southerly tilt would decrease as you approached the center, your power levels should show some increase.
Like removing the shades.

I think that the best return of investment for science is not to leave it standing around Victoria Crater which is already well known. Instead of standing, go away from Victoria Crater to some place in which the MER team think that it is the best. I have hope by roving, might have any surprises or any interesting stuff to study.

Listen, SL, I know where you're coming from. Seems like years since we were afraid to leave the computer lest we miss what was over the next rise. But the truth is that we entered Victoria in the first place to study its deepest strata. Those should tell us about the deeper past of the Meridiani Plain. More than we can learn anyplace else within country miles of here. We are only now approaching the level of those strata. Have we reached yet the age of the festoon ripples?
Gazing down at it from the bathtub ring doesn't count. We have to get down there and give it the old IDD right in the patootie!
Patience.

I agree with Shaka that we must continue down the crater. There is still alot of stuff to look at inside the crater, and science that needs to be done. However with Oppy crossing a boundry were there is much more blueberrys and dust, there is not much if not none of the crater wall layering exposed further down. The best science targets that I see is a more detailed study of those razerback features as we go down, and a close up analysis of Cape Verde, and Cabo Frio layering. But Much of the strata on those promentory's is reminisent to the stuff that oppy is now exploring.

Two distinct topics seem to being discussed in this thread. The first is what the contributors would like to see Oppy do next and the second is the statements from JPL regarding what Oppy will do next. It seems to be clear from the JPL statements that Oppy will drive out of Victoria soon and not very long afterwards will drive away from Victoria altogether.

The reasons given for driving out of Victoria are that Oppy can not safely drive much further into Victoria because is too much sand between and on rock slabs. It should be remembered that Oppy had considerable problems driving up to Burns Cliff in Endurance crater and very nearly slipped back onto the large rock Wompay.The second reason for driving out of Victoria is that Oppy's might be expected someday to loose a wheel much as Spirit has.

I would really like Oppy to complete its circumnavigation of Victoria crater. However reading between the lines of JPL press releases I can see that from a strictly scientific point of view Oppy is unlikely to see anything in the 2/3 of the rim of Victoria Crater that it has not investigated that it has not seen in the 1/3 of the rim that it has already investigated. I think that probably the only target worth investigating from a scientific point of view in the wall of Victoria crater is the linear feature close to the Soup Dragon.

I think that Oppy will drive fast South or South East in the next few months. An advantage of doing this is that I think Oppy would then be able to sample strata higher up the stratigraphic section than any exposed in Victoria or Endurance crater. I understand that Oppy sampled some such strata as it drove over the gentle hill overlooking Victoria crater. However I think that Oppy would be able to sample much higher strata in the stratigraphic section if it drives South of Victoria.

One target that I think would be worth investigating if Oppy drives South would be Explorer/Sofi crater. To me Explorer looks fresher than Endurance crater and I think that the contrast between the Endurance, Erebus, Victoria and Explorer craters would be interesting.

One thing to note about any drive South is that it would be difficult for Oppy to avoid driving for a long distance along the rim of Victoria crater which means that many more beautiful views of Victoria crater could be expected before Oppy drives away from Victoria crater forever.

There was once some talk of going back to Erebus.
I wonder if that is still a possibility and what other
possibilities are on the table as far as the real
deciders are concerned. (No, not G.W. Bush.)

The Getting to 'Big Crater' thread was an interesting discussion. Those annotated wide field orbiter shots of Victoria and 'Big Crater' provide a perspective on the size of these features.

If there is compelling science that is unfinished and can be accomplished with Oppy's instruments, by all means go back to Erebus (or anywhere else). From a photographic standpoint, following the route that brellis posted would be cool in the sense that the bit of crater rim may be very different from what we have seen (and possibly made of different types of rock), although actually making it would be relatively unlikely.

After having taken the risk of entering this crater, it is difficult for me to imagine the team not investigating the deepest available layers. Since those layers are so near and apparently accessible, the additional risk seems nominal.

Completing the circumnavigation might be fun, but I doubt that would be the best use of remaining resources. After Opportunity leaves Victoria, I'm open to exploration in almost any direction that leads to new bedrock observations. In the past I have argued that a return visit to Erebus would be a good idea, but I also think observations of available bedrock in widely separated places is a good idea.

Since we aparently have a rather small vertical selection of rocks to explore, Opportunity would be wise to continue exploration of the lateral variability of the bedrock over as wide an area as possible.

That's the thing isn't it. IS it accessible. We don't know that. It's fairly clear that if it is (in terms of navigability AND accessibility of the actual rock under the dust/soil covering) , they'll try to get to it. If not, they'll move on. We really don't want to spend longer or 'use' more rover than is necessary within the crater, as a wheel failure would appear to be not too far away, and with it - a navigational tomb stone.

Doug

Isn't the best roving plan for Oppy the one that maximizes the expected scientific value of the remainder of the mission? If so, then that isn't necessarily the same as the plan that maximizes the rover lifetime, or the chances of getting back up.

Spirit, in the course of its mission, has several times wandered across the borderline between one geological province and another. The bottomlands had one story to tell and then the hills had a different story, and Eldorado and the home plate environs also offered some new and non-obvious insights as the payoff for horizontal trekking. (Horizontal here means along the surface, although of course there were hills involved.)

But Opportunity landed by design on a big plain way larger than its roving radius, and I am sure I recall quotes from Steve and the other panelists during the early press briefings in which the mission at Meridiani was described as a search for holes - craters, that is - punched in the flat landscape to allow access to earlier strata. As we consider pulling the rover out of the largest of these holes before getting a closer look at the strata at the foot of the capes, just ask what are the hoped-for gains from further horizontal exploration outside the crater. The two-year hike down from Endurance to Victoria was undertaken because it promised access to deeper, older strata that were not accessible elsewhere. One of the reasons the journey took two years was because a lot of scientific investigation was performed along the way, and the strata accessible on the surface and in the shallower, more eroded craters are already quite well known to the science teams on that basis. (If I am wrong please correct me. This could change the arithmetic - but it ought to be more than "I'd like to have another look at that cross-bedding in Erebus" because one is balancing a second-or-third look against a "first look" at as-yet unseen strata.)

"Big Crater" seems way too far off for any reasonable hope of getting there. That being the case, before leaving Victoria someone better informed to really needs to explain to me why the risk-adjusted scientific payoffs now seem more fruitful outside the crater than at or near the pedestals of one or two of the capes. It's not clear how close we can hope to get, or exactly the odds on losing a wheel, or some other technical breakdown and not being able to climb out. But the capes are not too different from one another, so one campaign of a couple months' duration would likely suffice. I believe Burns Cliff was investigated in the local winter season. If it means running the same risks that were run back at Burns cliff, then I can't see leaving it undone. It's what we came to do - to look at the lowest, oldest rocks.

Peter

Well, I'm not better informed but here's my take at it...

"As you set out for Ithaca
hope your road is a long one,
full of adventure, full of discovery.
Laistrygonians, Cyclops,
angry Poseidon - don't be afraid of them:
you' ll never find things like that on your way
as long as you keep your thoughts raised high,
as long as a rare excitement
stirs your spirit and your body."

Get us out of the hole Steve!!!
This rovers were made for roving!!!

A failure that would prevent Opportunity from exiting Victoria, over
solid surface, would probably also trap the rover in the sand ripples
of the Meridiani plain. For that reason, I see crossing back to Erebus
-- or going anywhere over the ripples -- as being at least as risky as
further exploration of Victoria. Perhaps the coward's way out is to
spend the rest of the mission exploring Victoria's rim and apron.

I just asked SS if they are really considering leaving Victoria already?
Where to next, Ithaca? Erebus? Circumnavigation?...

He left me bitting my nails from here on...

"Wait and see... you might be surprised. - SS"

Wow. Sounds like the producers of "Lost".

My memory may be foggy (hey, I just became a grandfather!), but wasn't it the "pedal to the metal" driving that immediately preceded the first wheel problems on both Oppy and Spirit? I remember that Spirit started having wheel issues after the dash from Bonneville to the Promontory. And Oppy also had some problems beginning after several successive sols of record-breaking drives going south from Endurance (not to mention getting snagged in Purgatory). I really like the excitement of covering a lot of ground quickly, but it appears to be hard on the rovers if sustained for more than a couple of sols.

If we're going to be mythical, let's envision Oppy sprouting wings like Pegasus and floating to Ithaca on the gentle autumn Zephyrs.

I predict that they will be heading back to the smooth plains to the North, but will be taking a wide swing to the East to avoid the heavy dunes in the Erebus region.

Yeah. That's exactly what it comes down to in the end. We can only guess what the handlers will actually decide to do. We know they will be cautious in their navigation, but we also know that the reason the rover was directed to Victoria was because it was the deepest hole in the neighborhood.

After making the difficult, but fascinating trek to Victoria, we've learned a lot, but we are also disappointed to discover that this hole has not exposed the deeper layers we hoped to find. There are strong reasons why this rover should try to collect data from the deepest rocks it can access here, before moving on.

If they decide to move on, rather than study the deeper layers here, it's a long walk to a bigger hole. It seems that the best use we can get from the rover is to go somewhere else. Wherever these rovers go on this planet, they will make discoveries.

I totally agree with that point CosmicRocker and regarding Ithaca...huummm...looks far...I told Steve that the teaser induced me to that on the clouds nail bitting frenzy...then he pulled me back to solid ground...
"I don't think you'll find it to be all that dramatic. But we're not ready to leave the crater yet"...
Not that epic but it's what we've got for now...

I'm not sure if this has any relevence to the In/Out discussion to be honest, but I came across this very interesting HiRISE crater image whilst browsing recently and it set something buzzing in my head...

Click to view attachment

Un-named crater in Meridiani

... and, well, looking at the outcrops along its rim made me realise that Victoria is really shallow, and that after studying the new layer, with just that pool of sand ahead of us, perhaps we're not going to see an awful lot more here? (unless we drive closer to an outcrop and do some detailed studying of it...)

Just thinking aloud. Others will have more insightful comments and observations, I'm sure

I like your crater Stu. How far is it from Opportunity--maybe she can visit

Ithaca (Big Crater), or die trying. One advantage which we have now is high-resolution orbiter pics of the terrain, so there are unlikely to be any really troublesome surprises, and the dunes become less troublesome to the southeast. Ithaca is the most interesting and uniquely different feature conceivably accessible, and given enough sunlight and lack of hardware breakdowns, the more recent software update should make it at least as achievable as was Victoria.

Do we have HiRise pics that cover the entire route between Victoria and Ithaca? If so, please point me to them.

Thanks
Brian

It's amazing to have the luxury to have such an idea so late in the mission! I agree with you for a simple reason : if something brake in the way to Ithaca we'll be back to a simple lander instead of a rover. Once Vicky will be done, I see no advantage of having a lander at Vicky instead of on the plain; so let's go to Ithaca instead of spending years at Vicky or going back to known places . Need two years ? So what ?
This will be my choice.

No, we don't. We have quite a lot of terrain covered : http://hirise.lpl.arizona.edu/PSP_004289_1780 : but not all of it. Given our recent news of early symptoms of wheel failure, my opinion on this is firmer than ever before. If, after exhausting every possible scientific target in and around the Victoria annulus there are genuinely no other valid options, then why not. But I don't see that happening before the wheel failure is likely to occur, and at that point, it is, imho, a fundamentally impossible challenge. I see little point in abandoning accessible science for a target that all sensible consideration would deem inaccessible. With a brand new rover without 12km on the clock (2000% of it's design life), maybe, just maybe, it would be possible - and even if it were, it took two years to get from Endurance to Victoria. Do the maths. In a romantic world without technical failures and dune fields, bring it on. Sadly, that's not the case, and I genuinely, honestly believe people who suggest it should be done before every other possible option has been thoroughly explored are sending the rover to an earlier-than-necessary death.

http://global-data.mars.asu.edu/ctx/img/P0...1780_XI_02S005W and http://global-data.mars.asu.edu/ctx/img/P0...1780_XI_02S005W probably offer the best overview of the route. The easy 200m/sol terrain is visible as a slightly lighter tone that extends from Endurance for several km north - in a band that runs East-West. There is etched terrain similar to that of the Erebus-to-Beagle run (20-50m/sol with occasional dune fields ) runs west for a dozen KM, then south for a couple of dozen KM. I would suggest that might make more sense than anything else if you wanted to cover some ground.

But, lets be honest, all we're really doing is guessing. If we knew all the plans, it wouldn't be anywhere near as exciting

Doug

(PS - on the flip side, screw it - lets follow the thin ribbon of etched terrain E, then NE, the E, then S toward Ithaca that Ustrax suggested a long time ago. POinting SE and hitting 'go' would still be a bad idea)

I think it's pretty safe to say that I'm one of the most optimistic, rose-tinted-glasses-wearing, romantic rover-hugging members of the board, but even I can't put my hand on my heart and call for a road trip to Ithaca, because it seems to me that apart from all the technical, rover-in-peril related reasons already given - and they're all good reasons - there's one thing, one BIG thing, against it.

There's nothing to see there!

Take a look at this picture Ustrax posted back at the beginning of this thread...

Click to view attachment

... IF Oppy survived the trek to Ithaca, what would greet her there? Well, following Ustrax's route, she'd first come up against some Columbia-scale hills. Now, she's not going to climb those and look o'er the other side into the crater, is she? ( And even if she did what would lie ON the other side? A big, flat, featureless plate of a crater floor, that's what. ) So, she'd have to go "into" the crater from a bit further north... then what? It's a great big swathe of Meridiani, nothing more. True, there are some very impressive-looking mountains on the other side, but only impressive when seen from above; if you were walking alongside Oppy when she arrived at Ithaca, wouldn't those distant mountains just look like mere bumps on the horizon?

So, no sweeping vistas or jaw dropping panoramas at Ithaca. Good science then? Well, not for me to say, not being an expert, but surely Oppy couldn't study any rocks there at deeper levels than she's doing at Victoria? Or am I missing some outcrops on that image?

All in all, as much as it hurts the romantic poet in me, I have to say that, IMHO, Ithaca is a pretty poor target. Going there would be driving for driving's sake, with the risk of rolling to a sudden and juddering halt a dozen times each driving sol, leaving the rover - now a lander, essentially - stuck right on the corner of "no" and "where", with just the sky to stare up at and the distant horizon to glower at until she eventually died.

However... move her north, back to some of those smaller craters and features, and she could look for changes. Or keep her at Victoria, inside or outside - preferably outside - and even if she grinds to a halt she still has a lot to offer through monitoring changes in the vicinity, looking for frost or seismic events, checking for dust movement within the crater, etc etc...

I just don't think Ithaca is a realistic or useful target for our brave gal.

Actually - that's a good point. 1183_0000 HRSC ob has Vic and Ithaca in it.

Meanwhile, from HRSC view. - indicating something like 250m of elevation change from the rim to the floor. I'll have an animation session with it tomorrow night.

Doug

I'd just like to toss in the observation that Spirit first showed signs of increased current flow to its failing wheel motor when it arrived at the foot of the Columbia Hills at about Sol 258. By careful handling of her roving, it took nearly a thousand more sols for the wheel to fail, and some of the mileage put on her in between including scrabbling up to the top of Husband Hill.

Just because Oppy is showing signs that her already lightly lame wheel is beginning a slide into failure, is there any real reason to anticipate this failure occurring in a far less number of sols than it did between first symptoms and complete wheel failure on Spirit?

-the other Doug

And how many km. (answer, not that many)

Now how many km to Ithaca. (answer, many )

So, if you want to consider a 20km, then yes - there are real reasons to anticipate this happening 'sooner' than it did on Spirit.

Doug

Can't find that map...do you know where it is Doug?
That image you posted is quite awesome, never seen it before, could you pass some more info about it? Is that the maximum resolution? And a legend for the colours does it exist?

It's from here : http://hrscview.fu-berlin.de/cgi-bin/ion-p?page=entry.ion

Doug

Thanks Doug! And slinted...and algorimancer...
The puzzle, with the current available images, is almost complete:

Click to view attachment

Oh, I'm not saying that the wheel ought to be good for a 20-km trek. I'm just wondering why, at the very outset of a problem that took two Martian years to progress from initial symptom to complete failure on Spirit, we seem to be hearing "Oh, my, will the wheel last long enough for us to get out of Victoria?"

Shouldn't we anticipate that, for example, Oppy ought to be able to putter around Victoria and its annulus for another Martian year or two before its wheel locks in place, rendering her still mobile but much slower and unable to handle steep slopes?

-the other Doug

Another year or two, or maybe just another month or two, or maybe tomorrow. We don't know. We're guessing. You should be thinking km's, not years though I think. What is most probably is that it will fail at some point, and the middle of a dune field probably isn't the best place for it to happen.

Doug

You guys help the dumb here with the maths...EDITED: forget it, got the answer already...

Bridges...terrasses...there must be an abyss here somewhere...

Click to view attachment

Sorry Ustrax, even if Oppy made it to the near rim of Ithaca, any abysses in those features are still several years of driving away, even without the scientists wanting to do their pesky poking and prodding. And surely, we would want to take the time to climb one of them big hills on the near edge.

I'm wondering, now that we have Doug onside for the Ithaca trek, does that mean the dreamers have simply worn down his resistance, or does he know something he's not telling us?

Personally, I like the crater due west of Victoria, about two "endurances" away. It is closer than Ithaca, seems to have a nice path of etched terrain to follow, and the closest rim appears to have good exposed layers deeper than Victoria, assuming the slope is traversable. Has this crater been discussed in past speculations? Have we given it a name yet?

Brian

You don't really. What I've said is that there are many valid science targets in the Victoria aria, even back up to Erebus etc. Once all of those are exhausted and no other options are available, then a not-quite-utterly-horrific-but-still-idiotically-lengthy route to Ithaca would be a valid next step, if for no other reason than to cover ground in any direction.

Doug

I agree that a nondescript dune field isn't the optimum place for Oppy to become a stationary lander mission. The only thing I guess I'm taking exception to is the comment "We don't know. We're guessing."

Doesn't it make sense that, with an entire failure sequence with which to compare (of identical equipment under similar environmental circumstances), we *do* have the ability to do more than guess? Isn't there a certain amount of engineering rigor to making meaningful projections of the eventual failure of Oppy's wheel based on the observed failure of Spirit's?



-the other Doug

Let it be noted in the log of the starship Enterprise that I here voluntarily relinquished my opportunity to leap in with both feet punching, in deference to "nprev", who can better render justice from the font of technical engineering expertise.

oDoug,
We just can't make any statistical inferences based on only one sample point. Sure, Spirit lasted a good long while, but that doesn't tell us anything about Opportunity, simply because we don't have enough information, ie look up Law of Small Numbers. Even if you argued the 12 wheels are enough to give us some statistics, we are stuck because we would be comparing their first 1500 sols against their next 1500 sols, which are obviously very different.

If we had numbers on average time to fail at 3000 sols, then we could give reasonable estimates. Given what we know now, what a good engineer would say is that if we had a new rover, the odds are good we could make Ithaca. Beyond that, it's all hand-waving.

Even comparing the testbed rovers here on Earth wouldn't tell us much, because the environment here is so much more benign than on Mars.

I agree with Doug, explore the hell out of the nearby environment, and only then go for a suicide run to Ithaca. At least we would get another year or two of worthwhile scenery before the long haul.

Well - here's the Spirit story. It failed a bit, then we nearly stopped using it, then it was fine for a while, then it suddenly died totally. It was, perhaps coincidentally, the trenching wheel that died - but all 6 wheels did a whole LOT of trenching on Opportunity. Opportunity has a stuck steering actuator that may or may not make a contribution. Opportunity has done a lot more mileage, but probably less climbing, Spirit has had hasher thermal cycles, but Opportunity's probably had more jarring driving over open rock. To infer 'we've got X sols' or, 'X km' from that is a random guess.

Doug