[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.

[imran]

The latest power numbers from:
http://www.pasadenastarnews.com/Stories/0,...2810024,00.html

And thanks to an unexpected clearing off of its solar panels by a dust storm on March 9, Spirit is now operating almost like new. On March 8, the rover was operating with 427 watt-hours of power per day. On Wednesday, its power level had leapt to 838 watt-hours per day. "That's a huge jump,' Crisp said.

Opportunity's power supply was at 635 watt-hours Wednesday.

[Marcel]

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

Doug

Good points !
Except slipping downhill: driving without turning wheels

[ustrax]

I vote for Spirit.

It is a question of faith...

I'm sensing favoritism here.

What basis to you have to do a statement like that Greg?!

[dot.dk]

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....

So far the rover has lasted 5 times longer than planned. So the wheels will be good for 30,75 km at least

[tedstryk]

It might be interesting to take a new poll, since that one was started at a time when it looked like Spirit was going to keel any day from lack of power.

[Guest_Edward Schmitz_*]

I think we will be very surprised the day one of them stops. I predict it will be a complete mistery what happened. No signal, no explanation...

I pick Opportunity to last longer. Not that I don't like Spirit - it just has 21 more days on the ground than Opportunity. And Spirit has always had the worse luck. Let's count them:
1) airbag in the way.
2) software glick.
3) bumpier terrain.
4) didn't land in front of a rock outcrop.
5) hasn't met it's goal of confirming a lake at gusev.
6) wheel problem. (Op now has one too. but even here Op's wheel got stuck in a good position.)
7) dustier conditions. (even with the cleaning, it will probably build up fast, again.)

[Chmee]

I agree, the MER's ultimate fate will probably be a mystery. They will just stop transimitting one day ala Mars Pathfinder... Probably due to battery recharge failure.

[deglr6328]

I agree, the MER's ultimate fate will probably be a mystery.  They will just stop transimitting one day ala Mars Pathfinder...  Probably due to battery recharge failure.

Shouldn't the rovers be able to go day by day like sojouner did when its battery died? ie. they wake up with the sun and "die" every night at sunset. They have flash memory and some rom space so.... ? Anyway I'd love to see more engineering data like battery performance degradation etc. Nearly a year go the guys who built the battery (Lithion) said the rovers were limited not by battery performance but only by solar power availability.

[Guest_Edward Schmitz_*]

Yes, the rovers don't need the batteries. It would be just like deep sleep mode. The biggest difference would be that they would not be able to operate late into the day. Sometimes they are operating after 6:00pm. That would end. Operating time would probably be about 10:00am to 2:00pm.

[ustrax]

Dumb question...
Is it possible that sojourner may be still waitng for new orders?...

[Pando]

Considering the self-healing history of many of those problems with the rovers, I wouldn't be surprised if Oppy's steering motor starts suddenly working again...

[deglr6328]

Dumb question...
Is it possible that sojourner may be still waitng for new orders?...

Possible? yes. Probable? Not a snowball's chance in Caloris Planitia.

However, sojourner was programmed to drive around pathfinder at a fixed distance in a circle when (if) it couldn't find a signal after it woke up in the morning. Sojourner almost certianly continued to circle for at least some time though, forlornly listening in complete desolation for a signal that it wasn't alone; a signal that would never come. After seeing the amazing resolution of MGS imagery of the MER landing sites using the "slewing" technique though, I bet we could see a dark ring of disturbed soil around the pathfinder site if it were still circling or if wind processes haven't completely erased old tracks. I suspect that neither of these scenarios are likely enough to warrant taking some MGS science time to do the imaging though.

[Guest_Sunspot_*]

Considering the self-healing history of many of those problems with the rovers, I wouldn't be surprised if Oppy's steering motor starts suddenly working again... 

Is that a subtle hint?

[chuckyvt]

From what I recall, the Sojouner batteries never failed while the lander was operational. The Sojouner rover had a set of non-recharable batteries, but I don't remember any news of them dying, I could be wrong. The recharagable batteries on the lander did die however, towards the end of the mission. While the Pathfinder lander, as well as the MER rovers apprently, could operate on solar power alone, the failure of the battery pretty much sounded the end of the Pathfinder mission. Since the lander was no longer able to operate and control its internal temperature at night, the increased thermal cycling probably lead to some failure that caused loss of contact with Pathfinder.

I agree, the MER's ultimate fate will probably be a mystery.  They will just stop transimitting one day ala Mars Pathfinder...  Probably due to battery recharge failure.

Shouldn't the rovers be able to go day by day like sojouner did when its battery died? ie. they wake up with the sun and "die" every night at sunset. They have flash memory and some rom space so.... ? Anyway I'd love to see more engineering data like battery performance degradation etc. Nearly a year go the guys who built the battery (Lithion) said the rovers were limited not by battery performance but only by solar power availability.

[djellison]

Sojourners batteries gave up after a few weeks and it became a fully solar powered mission.

doug