[X] My Assistant

[remcook]

I hope we won't have the result for this one in quite some time, but Spirit had some steering problems (only steering problems though)

so which one is going to last the longest?
Oppy did much less legwork, so my guess is on it.

[Bill Harris]

then the entire planet would be exactly the same colour

But it is! Mars is Ochre with varying degrees of Saturation and Lightness (HSL model).


I think that the "iron oxide" dust gets ground down to the molecular level and clumps to make bigger particles. That limonitic dust pervades everything, I'll bet!

--Bill

[djellison]

then the entire planet would be exactly the same colour

But it is! Mars is Ochre with varying degrees of Saturation and Lightness (HSL model).

We've got Meridiani that suggests otherwise

Doug

[imran]

No love for Spirit

30-4 in favor of Oppy. I thought it would be much closer than that.

[MizarKey]

No love for Spirit 

30-4 in favor of Oppy.  I thought it would be much closer than that. 

Spirit is in much rougher terrain and for a long time was only running on 5 wheels (though that's been rectified). Oppy is out there on the relatively flat terrain and it's major obstacle is avoiding falling into Victoria crater (anyone taking odds?).

I'd like to see them both make the 1,000 Sol mark.

[slinted]

Opportunity might be leaving the 'parking lot' within the next couple weeks. The etched terrain might present significant driving hazards, and the dunes themselves are growing. We might have been fooled into thinking these drives were easier than they should have been, mainly because Oppy has been running straight south aligned with the dunes. If she had to cut across a sandy dune every couple of meters, we'd be looking at significantly slower drives I'd imagine.

[dvandorn]

Opportunity might be leaving the 'parking lot' within the next couple weeks.  The etched terrain might present significant driving hazards, and the dunes themselves are growing.  We might have been fooled into thinking these drives were easier than they should have been, mainly because Oppy has been running straight south aligned with the dunes.  If she had to cut across a sandy dune every couple of meters, we'd be looking at significantly slower drives I'd imagine.

If you look closely at the super-hi-res images of the area, you can see that the evaporite outcrops tend to break up the dunes. It's a little circuitous, but it looks like Oppy will be able to chart a course through pretty flat ground.

I don't think Oppy is going to find a lot of problems in trafficability yet. I think that Spirit is definitely going to be traveling rougher ground than Oppy for some time to come, and that's got to be rougher on the wheels and the associated mobility systems. So, I think the odds are pretty good that Spirit will be the first of the two immobilized. But immobilized is not necessarily dead...

-the other Doug

[Marcel]

Opportunity might be leaving the 'parking lot' within the next couple weeks.  The etched terrain might present significant driving hazards, and the dunes themselves are growing.  We might have been fooled into thinking these drives were easier than they should have been, mainly because Oppy has been running straight south aligned with the dunes.  If she had to cut across a sandy dune every couple of meters, we'd be looking at significantly slower drives I'd imagine.

If you look closely at the super-hi-res images of the area, you can see that the evaporite outcrops tend to break up the dunes. It's a little circuitous, but it looks like Oppy will be able to chart a course through pretty flat ground.

I don't think Oppy is going to find a lot of problems in trafficability yet. I think that Spirit is definitely going to be traveling rougher ground than Oppy for some time to come, and that's got to be rougher on the wheels and the associated mobility systems. So, I think the odds are pretty good that Spirit will be the first of the two immobilized. But immobilized is not necessarily dead...

-the other Doug

Now that i've seen the concentration of dust devil tracks on Spirit's site on the Gusev fly-over thread, I believe the cleaning event of last month isn't going to be the last one for Spirit. At Meridiani however, no dust devils are seen, nor is evidence for them being active there. So, oppy's more likely to get dustier in the end.

So, i voted for Spirit.

This is supported by my idea (gut feeling), that the roughness of the terrain isn't of so much influence on the wear of rolling(wheel)parts. Velocity is far too low for "bumping", so no significant extra sideforce/impact is exerted on the wheels. The only "wear-factor" that's left (to me) is the number of revelations of bearings and motors*. Since Oppy has overtaken Spirit in driving distance nowadays, one should say oppy's wheel are just as worn out as Spirit's.

Availability of energy (=amount of dust on the arrays) seems the only factor left. Except sudden failure of a critical component, which can't be predicted.....and, ofcourse the end of the battery (stamina of 2000 sols). After that, we'll vote again

*PS: how many revelations can the wheel motors handle ? Any numbers ?

[Jeff7]

[q]Since Oppy has overtaken Spirit in driving distance nowadays, one should say oppy's wheel are just as worn out as Spirit's.[/q]

However, I think they started driving Opportunity backwards occasionally, after Spirit's wheel started acting up. So its wheels might be in better shape, due to "preventative maintenance."

And wheels don't have revelations, at least not religious ones. They only make revolutions.

[djellison]

They started drivin Spirit backwards after it's wheel issue - and that has since vanished

We have 12 healthy wheels on mars.

The only issues I know of are...

Stuck IDD heater on Opportunity that gets turned off via deep-sleep at night
Slight non-damaging short on Spirit somewhere
Oppy Mini-TES still off-line for analysis
Spirit RAT teeth possibly worn out.

The last point says a lot about the composition of the rocks between Gusev and Meridiani. As of December - the score was

Grind Brush

Spirit 11 39
Oppy 22 8

Now - since then, I believe we've done four rattings on Spirit, and 1 on Opportunity - so the score is probably around 15 - 21. Yet Spirit's the one that's worn out

Doug

[centsworth_II]

Spirit RAT teeth possibly worn out.

From the latest NASA/JPL press release:
"Researchers probably won't know the extent of wear until Spirit's next rock-
grinding attempt, which may be weeks away."

Hopefully they are being (justifiably) over cautious and the next RATting will prove the teeth to be just as sharp as ever.

[ustrax]

I vote for Spirit.

It is a question of faith...

[Buck Galaxy]

Spirit has the tougher terrain so I would have to go with Oppy. Besides I'm a dreamer and I want to see Oppy make it all the way to the gigantic crater about 10 km south of Victoria. :-)

Something I'm surprised about is how the microscopic dust particles haven't clogged up/damaged any of the Rovers' gears or instruments. Maybe the dust issue with relation to a manned landing on Mars won't be as bad as some people think.

[gregp1962]

I vote for Spirit.

It is a question of faith...

I'm sensing favoritism here.

[Marcel]

[q]Since Oppy has overtaken Spirit in driving distance nowadays, one should say oppy's wheel are just as worn out as Spirit's.[/q]

However, I think they started driving Opportunity backwards occasionally, after Spirit's wheel started acting up. So its wheels might be in better shape, due to "preventative maintenance."

And wheels don't have revelations, at least not religious ones. They only make revolutions.

Sorry...uh...I mend rotations/revolutions.

Found it: 2,5 million. With a gear ratio of 332: 1, this means 7530 revolutions

With a wheel-circumference of 81.7 cm....this would be 6.15 km's. Hope they last longer....

[djellison]

And that doesnt take into account the usage for trenching, turning in place and slippage etc.

Doug