Spirit & Opportunity survival - Could they srvive to Mars winter?

cassioli · 2004-03-05 08:22:02

I read that Spirit and Opportunity will eventually stop working due to two factors:
1) Dust covering their solar panels
2) Sun maximum elevation decreasing while Mars winter approaches

Can these problems be solved in any way?
If I remember right, rovers' panels where folded, while inside the lander: could they be folded/unfolded again, to scroll away dust from them?
If the solar panel won't eventually furnish enough power to recharge batteries, will the rover die, or will they just "freeze", so they could be turned on again on next Mars summer? Maybe they can't work at -100?C , but maybe they will not break, just stop working... or not?

What about '97 Sojourner? Why couldn't it be "resurrected" after one Martian year? Did it have the same winter-problem, or was it just buried with martian dust?

Luca

RobS · 2004-03-05 09:27:45

I think the main problem is the batteries; when they get too cold, their chemistry is permanently altered and they don't store power any more. The rovers have RHUs--radioactive heating units--so that helps. But the cold does eventually do permanent damage. We have little experience engineering equipment to survive 100 below.

-- RobS

Rxke · 2004-03-05 09:48:36

Sojourner's 'Home base' (Yhe Carll Sagan Memorial) went dead before S. itself, and since S. needed that to communicate with Earth, unfortunately it is not known how S. ended...
I read on /. from a guy who claimed to have been working on that mission, they let S. drive over bigger rocks, and the 'bump' that caused this, dislodged some of the dust from the panels, but only minimally so (the dust is charged, so it 'sticks' to the panels...)

RobertDyck · 2004-03-05 09:58:36

Once a battery freezes, it tends to not hold a charge. If the battery bursts and acid leeks out, not only will the battery never work again but the acid can destroy electronics it drips onto. You can design a battery to handle freezing, but standard batteries do not.

Designing electronics to 'hibernate' is difficult. Commercial electronics only work between 0?..+40?C. Automotive electronics are designed for -40?..+65?C and military electronics are designed for -55?..+65?C. You have to design the 'wake-up' circuit to operate at Mars ambient temperature in the morning, charge the battery from solar panels, then start the heaters to raise the temperature so everything else can work. I doubt Sojourner, Pathfinder, or either MER already has that.

Sojourner didn't fail, Pathfinder did. The little rover was designed to send its signal to the lander, and the lander would relay to Earth. The battery on the lander failed due to cold weather at night. Sojourner was orphaned.

cassioli · 2004-03-05 10:06:51

I think the main problem is the batteries; when they get too cold, their chemistry is permanently altered and they don't store power any more. The rovers have RHUs--radioactive heating units--

Really? I didnt' know this.
Why not to power the whole rover with nuclear power?!? It would never die! Even no need for batteries, as nuclear power generator are always on, even during the night.

I thought current space mission didn't use nuclear power, due to Earth environment safety problems! ???

Luca

Lars_J · 2004-03-05 11:16:34

The next rover in 2009 will be nuclear powered through an RTG. It is being designed to be able to rove around on Mars for a year or more.

As for current and othr future missions using nuclear technology:
Cassini uses RTG's as well - as did Galileo.

JIMO (Jupiter Icy Moons Orbiter - formerly project Prometheus) is a pretty exciting mission as well, planned for launch in 2012. It will be the first interplanetary mission to use a nuclear reactor (not RTG), which will be used to power an ion drive. [http://www.jpl.nasa.gov/jimo/]NASA JIMO homepage
[http://www.jpl.nasa.gov/jimo/art/jimo_o … browse.jpg]JIMO schematic

DanielCook · 2004-03-05 14:26:07

If I remember right, rovers' panels where folded, while inside the lander: could they be folded/unfolded again, to scroll away dust from them?

The solar panels were locked into place once deployed - so they cannot be folded back again. (I think this question came up during one of the NASA press conferences a while back)

I noticed this article on the MER site this morning on one of the measures used by NASA to address dust:

[http://marsrovers.jpl.nasa.gov/gallery/ … 0304a.html]Mars Magnet Hits the Bull's-Eye

Lars_J · 2004-03-05 14:34:39

Given that both Opportunity and Spirit are located very close to the Martian equator, I wouldn't think that the seasonal change would be very noticable at all.

I suspect solar panel degradation (dust) and battery degradation (constant recharging + thermal issues) will be what seals the rovers fate rather than the Sun's position.

atomoid · 2004-03-05 23:04:59

They let Sojourner drive over bigger rocks, and the 'bump' that caused this, dislodged some of the dust from the panels, but only minimally so (the dust is charged, so it 'sticks' to the panels...)

if the dust has a charge like a static charge, didnt they give the panels an anti-static coating? and wouldnt it would be possible to apply a charge to the solar panels in some way to repel the dust?

The next rover in 2009 will be nuclear powered through an RTG. It is being designed to be able to rove around on Mars for a year or more.

The Viking landers both used RTGs (which are more expensive and beurocratically difficult than solar panels, but thats what NASA is for) and as a result, operated for many years, yeah SIX years!!, you dont have to worry about batteries with RTGs since they supply constant power, maybe some capacitors to get a high enough charge for some experiements but those dont have such problems, the problem was that the Vikings couldnt move so they were stuck in one spot with one vista and couldnt reach farther than their trencher would let them so there was nothing new to see after the initial mission ended, except for that they were able to get seasonal weather monitoring and pictures including water frost on the soil every winter:
The Viking 1 lander landed on the western slope of Chryse Planitia (the Plains of Gold) on July 20, 1976 and functioned until November 11, 1982. The Viking 2 lander landed at Utopia Planitia on September 3, 1976 and functioned until April 11, 1980

I am hoping (okay... grovelling, pleading, and begging!), that they will make the 2009 rover mission a TWO rover mission (the absolutely necessary proven-in-practice redundancy factor just cant be dismissed, especially when it comes to our track record on landing things on Mars, so we got lucky in 2004, can we really bank on a future 100% success rate?), it really cant be that more expensive than sending one since most of the costs are in the engineering side, not the equipment (okay rocket boosters are expensive, but add it up... can NASA afford to lose an _entire_ launch window's worth of progress? remember how the loss of polar lander doomed its next of kin 2001 lander (to eventually be recycled in 2007 as Phoenix) since the designs were similar? so we actually lost TWO missions (two launch windows) as a result of one botched landing, so it makes me cringe that all they have planned so far for each of 2005, 2007 and 2009 missions is just 1 probe each launch window...)

IMHO we should send two mission every window, each year we could send a copy of the Mars-tested MER each window as a backup. We could outfit the arm with new experiments each time as called for by the latest discoveries to test theories or do life-seeking experiements, that way NASA would have some success-insurance on a proven platform rather than run the risk of losing a whole window to a chance botching with a new untested platform (well, increase the odds at least). These MERs seem like a great platform, lets reuse the design or spend a little more on outfitting one with new experiments and better yet an RTG to take it throught he winter. imho at least one surface mission should be sent every window, since its the human-scale images and evirons that get the public involved and help tip the politcal will to support space exploration. Also, the surface of Mars is so diverse that we could take a chance on landing one of the redundant rovers in some less-safe areas where we could get better science and vistas...

Stephen · 2004-03-09 01:04:08

I read that Spirit and Opportunity will eventually stop working due to two factors:
1) Dust covering their solar panels
2) Sun maximum elevation decreasing while Mars winter approaches
Can these problems be solved in any way?

Probably not from Earth.

But didn't I read somewhere that when they built the MERs the engineers gave the MERs a greater degree of insulation than they might otherwise have done? (And as a result for a time some were worried that the rovers might get too warm!)

Shaun Barrett · 2004-03-09 01:51:54

I agree, Atomoid. Two probes are better than one!
I think the 2009 rover is going to be BIG, though, and therefore it may be too expensive to send two of 'em.
Mind you, if it were up to me, I'd send six or eight ... or ten!! But then, I'm what you might call an enthusiast!

cassioli · 2004-03-09 15:23:46

I agree, Atomoid. Two probes are better than one!
I think the 2009 rover is going to be BIG, though, and therefore it may be too expensive to send two of 'em.
Mind you, if it were up to me, I'd send six or eight ... or ten!! [...]

Just wait until Opportunity or Spirit will find even a little, very VERY little evidence of even microbial past life on Mars... and we'll have BUSes & TAXI going to Mars! :laugh:
Or, if rovers will discover some kind of precious material... just enough to payback the mission costs, and... :band:

Luca

Adrian · 2004-03-11 17:28:53

I just spotted [http://news.bbc.co.uk/1/hi/sci/tech/3503430.stm]an interesting article on the BBC that mentions 'scientists recently made new estimates of the rovers' lifetime on the planet, that extend their working life from 90 days to 240 days.'

240 days? What a result! It simply boggles the mind how much rover technology is improving these days. These things could travel miles!

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#1 2004-03-05 08:22:02

Re: Spirit & Opportunity survival - Could they srvive to Mars winter?

#2 2004-03-05 09:27:45

Re: Spirit & Opportunity survival - Could they srvive to Mars winter?

#3 2004-03-05 09:48:36

Re: Spirit & Opportunity survival - Could they srvive to Mars winter?

#4 2004-03-05 09:58:36

Re: Spirit & Opportunity survival - Could they srvive to Mars winter?

#5 2004-03-05 10:06:51

Re: Spirit & Opportunity survival - Could they srvive to Mars winter?

#6 2004-03-05 11:16:34

Re: Spirit & Opportunity survival - Could they srvive to Mars winter?

#7 2004-03-05 14:26:07

Re: Spirit & Opportunity survival - Could they srvive to Mars winter?

#8 2004-03-05 14:34:39

Re: Spirit & Opportunity survival - Could they srvive to Mars winter?

#9 2004-03-05 23:04:59

Re: Spirit & Opportunity survival - Could they srvive to Mars winter?

#10 2004-03-09 01:04:08

Re: Spirit & Opportunity survival - Could they srvive to Mars winter?

#11 2004-03-09 01:51:54

Re: Spirit & Opportunity survival - Could they srvive to Mars winter?

#12 2004-03-09 15:23:46

Re: Spirit & Opportunity survival - Could they srvive to Mars winter?

#13 2004-03-11 17:28:53

Re: Spirit & Opportunity survival - Could they srvive to Mars winter?

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