Rovers to get extra time on Mars

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So the rovers were "supposed to be on the planet for 90 Martian days."

I wonder what the plan was for removing them from the surface after that time!

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Two-Guys-With-a-Truck was (were?) to pick them up. :P

English as a second language, first is gibberish. ops:

I still would like them to have got the two to meet up, but as pointed out in an earlier thread it would take a Loooonnnnnngggggggg time

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I wanna go find the earlier landers. Just imagine a portrait of Pathfinder and Sojourner taken by Spirit or Opportunity.

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Opportunity is actually "just" a couple hundred kilometers southeast of Pathfinder, and not much farther beyond that is the Viking 1 Lander. No problem!

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If the rover keeps healthy, it just might reach them in a century or two...

I remember in the early '80s, there was a grass roots effort asking for donations from the general public to keep the Viking landers operating. Pennys for a starving robot. I remember seeing the ads in Astronomy magazine, picture of Viking with a can full of pencils held out on its sampling arm. Don't remember how successfull they were. But maybe someone can do that today.

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Not that long. If Opportunity headed in that direction and could maintain Spirit's pace (100 meters/day), it would probably only take two or three (Earth) years. No problem!

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Great news on the extension.

And I hate to look a gift horse in the mouth but I can't help but wonder why a machine built for 90 days isn't beginning to catastrophically fail after, say, 120 days. Was more $ spent on it than should have been? And if the two rovers can be anticipated to be running for 6 months to a year on bonus time, how much better might they have performed if some of its elements weren't merely rated for or limited to 90 days operation. Could the rovers have given a better return if they had been specifically built for 6 months to 1 year's use? Maybe a little extra $ could have been spent upgrading a number of likely critical 90-day failure items in order to ensure the extra scientific return possible with a 1 year mission. (Like the wheel mechanisms.) This is something that appears to not to be the case by overtly stating the rover life expectancy as 90 days.

Having said that, I'm sure the rovers must have been built with far more than 90 days in mind and that their budget has always included engineering provision for making them run for up to a year - in spite of the fact that there appears to be no project budget to actually run them that long.

Just a rabble-rousing thought exercise here as I have nothing but the greatest admiration for the entire NASA/JPL Mars rover team.

RBG

Maybe because they didn't have GM build them?

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When they build something to last for 90 days, I'm assuming that means that the parts have a 90%+ chance of lasting that long, not 50%. And a high probability of lasting 90 days translates into a reasonable probability of lasting 180 days, and so on.

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I think I remember hearing at one of the press briefings that the rover components were tested to the equivalent of at least 250 sols, possibly 270.

Design philosophy. The program is given a requirement "Must have an operational life of 90 sol." Thus the designers set out to ensure everything will last at least 90 sols, with the worst expectable conditions. Also, it's not like you can pick components that say "life = 90 days, life = 85 days, life = 110 days". Then there are variables that can't be known beforehand - amount of dust build up on solar panels, dust in the atmosphere cutting down on light, actual cycle time put on motors and drive components, etc. These can be guessed at but cannot be a known quantity ahead of time. Ergo, the designers take their best guess or provide guidelines and work to them.

Nothing can be a guaranteed certainty, but you want to do everything you can anticipate and control to see that the mission requirements are met.

Also, not everything runs out on the same schedule. Notice that the MiniTES is about dead because of thermal issues, and one wheel on one rover is sticking, but the others seem fine and the RATs are going strong. Well, RATs probably take a bit of power so are likely going to be on rest for the winter. Still, as long as things are semi-functional it makes sense to keep using them.

Are both MiniTES's nearly dead? I didn't know that. I thought they were surprisingly surviving the low-temp deep sleeps until now.

RBG

I believe when they fail, it is catastrophically. So being nearly dead is not the same as barely working.

The failure they expect was from low temperatures, when stress would cause some part of the optics to crack.

Ah. Here it is.

In deep sleep, without the heating on, those temperatures are closely approached overnight, maybe even reached. Failure hasn't happened -- yet.

Keep your fingers crossed.

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Well when Spirit is traveling it can do 100 meters/day, but a good chunck of the time it is examining something interesting, resting out the winter (as it might do later), having computer problems, etc. And of course there might a bunch of things in the way like hills, etc. to cross or go around...

Of course we all would be happy if these things lasted an impossibly long time. Would it not be wonderful if they could at least last until the next probe. Not going to happen though :-(

On a more serious observation, NASA is going to have probes with the good luck of lasting beyond their expected lifetimes. Maybe it would be prudent to put in the budget a few million a year in expectation this will happen. If no probes have excess survival some year then put the money into a loose equivalent to a rainy day fund. Also if one probe dies early its oporating funds would be put into fund. Of course political realities might rule out such a common sense approach.