Sunspot said: Is Endeavour still a realistic target? With the limited driving per sol, the problematic wheel/possible wheel failure and the lengthy stops to rest it, and also the new route adding 2 or 3 KM? Is there anything else around that might make a realistic target? Or are we now too committed to Endeavour to get to another target?

Endeavour is certainly worth going for...the idea is to try. It's not as much a goal as a direction.
Steve Squyres said: "We may not get there, but it is scientifically the right direction to go anyway."

Is reaching Endeavour possible? There is no reason to currently think it isn't.
Yes, Opportunity is getting older, there's potential problems for its long term mobility, but if these Rovers have taught us anything, it's to never say impossible. Add to that...the Rover planners and drivers have 5.5years of experience to draw on, and we know from watching them that they never say impossible either.

Are there other places for Opportunity to go that are closer? Yes! She's driving across it right now.
There'll be plenty of places along the way that will be scientifically interesting and will extend our knowledge of this region.

"I would love to see that view from the rim," Squyres said. "But even if we never get there, as we move southward we expect to be getting to younger and younger layers of rock on the surface. Also, there are large craters to the south that we think are sources of cobbles that we want to examine out on the plain. Some of the cobbles are samples of layers deeper than Opportunity will ever see, and we expect to find more cobbles as we head toward the south."

Will Opportunity reach Endeavour? I hope so. If she doesn't? I for one won't be disappointed, it's been 5+ glorious years of exploring Mars.

This may be a stupid question, but...

How is the "resting the wheel" stuff calculated? That is, given that Oppy has a finite lifetime (well, presumably), how was it determined that Oppy has more chance of getting to Endeavour (or, in general, getting more miles in its remaining lifespan) by taking it slower now and resting the wheel, vs. going all out now with 100m+ drives each sol and dealing with 5 wheels if and when that happens?

If I recall correctly they began noticing higher current draws from that wheel at the end of long drives. They also noticed that the currents either dropped or returned to nominal after long rest/science periods. Short rests didn't have much effect on the current draw problem.

I understand your question. I too, have been wondering about the very same thing. i.e. considering the fact that resting days too will probably shorten the 'remaing life-span' because of wear caused by the sharp thermal cyles, the dust accumulation etc. ...

Well to be strictly logical here, there is no statistical data to calculate the odds for complete rover failure on any particular sol for MER flight models. The only data we have is open ended and points to astronomically longer lifetimes than design parameters dictate. With the denominator still being zero the numbers we have at this point dictate an infinite lifetime (strictly speaking). There is however a data set for wheel-failure for an identical vehicle under nearly identical conditions. So in choosing to calculate risk on one or the other, they have to go with the wheel-failure data and work around that.

Well, we know they can't last beyond December 21, 2012.

Is it not all down to the MER teams' pure and utter skill...?

Subject continued here

http://www.unmannedspaceflight.com/index.p...20&start=20