Who Is Going To Live Longest? Options

[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.

[slinted]

I've got to go with Opportunity on this one, if only because its been through so much less trouble than Spirit at this point. Spirit had the rebooting problem, Spirit has the bum wheel, and now the steering problem on top of 3km+ under its belt. Wear and tear aside, I think Opp's long drive south is going to be an easy one as well. The plains looked like a parking lot, certainly an easier drive than what Spirit had approaching the hills.


Although...If all they do with Spirit is drive to the top of Husband Hill, and park it there for eternity (making it the coolest webcam ever) I'd have to go with it instead.

[akuo]

Based just environmental, electronical and mechanical issues, I'd say Spirit is going to last longer. In theory both rovers had the memory bug, Spirit was just the first to manifest it. The motors and mechanical parts in the wheels get worn when the rovers are driven long distances, there is no avoiding that.

The deciding factor is in my opinion the power situation. Opportunity has the stuck on heater that affects it even with the usage of deep sleep. Meridiani is also on higher elevation than Gusev, resulting in colder conditions and more power used on heaters.

Having said that, I think the mission control might shut down one of the rovers at some point and based on current results, it would be Spirit.

antti

[imran]

Actually Gusev Crater is in a colder area since it is a significant distance south of the equator where as Opportunity sits just on the equator. Also about a month or so it was reported that Opportunity was generating 600+ watts of power, about 200 W more than Spirit. And of course Spirit is showing its age with all the wear and tear. Based on everything we know, it seems unlikely that Spirit will live longer than Opporunity.

[imran]

As far as the heater issue with Opportunity, I don't think it is having much effect on the rover. The power numbers back this up. It seems they have found a way to work around this problem.

[djellison]

Yup - deep sleep turns it off totally. Sure - it's in use all the time the rover is actually ON - but that's often less than 8hrs a day.

I think Oppy is going to suffer power-wise once it leaves the crater. It's had an almost permenant 10 -20% tilt toward the sun for the past 6 months wandering around Endurance crater - and it wont have any tilt at all once it's back out on the plains. This will cause it to drop quite a lot of it's WHr/day budget.

Spirit on the other hand - has many months of climbing ahead, and whilst, yup, that's hard work - it's going to remain fairly sun-pointed for the duration.

Doug

[imran]

Now would be a good time to bring this old thread back up

So now that Spirit is generating about 830 watts compared to Oppy's 600+ watts, who would you now pick to last longer? I'm gonna stay loyal to Oppy and stick with her

Spirit is in a generally dustier area so I would presume it's power numbers are going to decline faster unless of course another dust devil decides to scoop by!

[gregp1962]

The dust devil incident changes everything. I have a feeling that the end of these things will be a result of things that haven't even manifested themselves yet. At first, we thought power would be the limiting factor. Now, we can assume that dust on the arrays will be a cyclical thing. At least in Gusev.

I think that when they are no longer mobile because of mechanical problems, they might be communicating with us for years and years. Maybe, they will find a good use for them in studying atmospheric or other conditions over decades.

[ilbasso]

I think the cold is what's eventually going to get them. The freezing/thawing cycles will eventually take their toll on one or more critical components.

[djellison]

I've got £5 that says it's the batterys (because of the temp and charge cycles)

Doug

[akuo]

A (major/global) dust storm. The rovers are now entering the dust storm season, and I think this poses the biggest threat at the moment. I reckon a dust storm might dump as much dust on the solar panels in a couple of sols as fell on Spirit's panels during the first 400 sols of the mission. This combined with the reduced sunlight might leave a rover stone cold.

I remember reading that the batteries were rated for around 2000 sols. Other electrical failures are of course a possibility, but at the moment I'd rate the dust storm season a bigger threat.

[Jeff7]

A (major/global) dust storm. The rovers are now entering the dust storm season, and I think this poses the biggest threat at the moment. I reckon a dust storm might dump as much dust on the solar panels in a couple of sols as fell on Spirit's panels during the first 400 sols of the mission. This combined with the reduced sunlight might leave a rover stone cold.

I remember reading that the batteries were rated for around 2000 sols. Other electrical failures are of course a possibility, but at the moment I'd rate the dust storm season a bigger threat.

I wonder...say a rover was totally covered in dust. What if it were cleaned off at a later date? Might it be able to reboot itself then? Maybe they could program something into it in anticipation of a dust storm, and send it into hibernation, waking up every month or so, check the power levels, and if they're at a certain level, try to acquire Earth's position and send a signal.



What about the radioisotope heaters in the warm electronics box? I imagine that they will continue to emit heat for a long time, but when will it reach the point of being too cold?

[centsworth_II]

I've got £5 that says it's the batterys (because of the temp and charge cycles)

Doug

The question has been asked before: How useful would the rovers be after battery failure, using direct solar energy alone? Could they go on as stationary platforms doing long term atmospheric/weather studies with their cameras?

[Marcel]

I've got £5 that says it's the batterys (because of the temp and charge cycles)

Doug

The question has been asked before: How useful would the rovers be after battery failure, using direct solar energy alone? Could they go on as stationary platforms doing long term atmospheric/weather studies with their cameras?

I remember asking that question indeed. I bet it can even drive without problem on solar energy solely. Not as much as with battery-charge offcourse. Rebooting after a cleaning event would surely be possible, as long as you tell them to do so. Right now, it's probably not programmed for such a long term hybernation, though the daily cycle of waking up in the morning is done by the sun isn't it ? Probably after reaching a certain level of potential, the booting sequence is initiated. I wonder if we should be afraid so much of dust storms though:

Isn't it the case that the only reason why there's so much airborne particles during a global duststorm, is because the winds are stronger than normal ?! In that case, dust is just as easy removed from the panels, as that it is deposited ! Maybe cleaning events are even more frequent (and stronger) during dust storms ! Maybe not

[djellison]

Yes - if dust storms did nothing but deposit dust - then the entire planet would be exactly the same colour

Doug