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[mike]

They have to see if they can get the IDD working at some point. Why would they just completely give up on it without trying all the possibilities? Once they've tried everything they can think of to make the IDD work again, I'm sure they'll move on and do whatever they can (and periodically see if they can get it working again beyond that).

[Decepticon]

I figured out the real problem. Something is stuck under the arm.

[tasp]

{how'd that get there?}

[ElkGroveDan]

I figured out the real problem. Something is stuck under the arm.

You win the prize again -- somebody tell Fifth Star or whatever his name was.

[edstrick]

IF... big if.. let's hope not... they can't get the arm back in operation, the mission methodology changes to an essentially purely remote sensing operation. They drive to a target and do multispectral images and Mini-TES. Overall travel rate might increase by 50%, and the nature of observation/experiment objectives changes a fair bit.

[Cugel]

Suppose the risk of moving the arm and then getting it stuck in a stretched position is so big, management decides to leave it where it is now. Would that actually render the IDD completely useless? Would it still be possible to move the arm in the up/down direction and rotate the instruments head? If so, losing the movement in the x-direction can be compensated for by driving the rover right over the target. Of course this would mean a great limitation in the targets that it can investigate, basically only those that you can roll over are now within reach. But something is better than nothing, as an old Chinese saying goes...

Also, from an engineering point of view, it is very interesting to see how this vehicle slowly degrades. Lessons for next missions (manned and unmanned) can be learned by just watching which components fail and in what order. So, I wouldn't kill the mission too soon but rather stretch it as far as it goes (can talk to us).

[vikingmars]

Well... Even with no IDD, we have a (i) spacecraft that can move & (ii) able to do a lot of imaging and observations, (iii) with a TES working for which we can still make some kind of rock abrasion with the wheels...
Anyway, better than a Viking Lander !

[Jeff7]

And really, if the rover becomes a mobile camera platform, well hey, we've got Hubble, whose main mission is simply to take pictures. These things can still do a lot of work, even if it is "just" taking pictures.

Also, from an engineering point of view, it is very interesting to see how this vehicle slowly degrades. Lessons for next missions (manned and unmanned) can be learned by just watching which components fail and in what order. So, I wouldn't kill the mission too soon but rather stretch it as far as it goes (can talk to us).

Seems like lubrication is a big issue. It nearly paralyzed one of Spirit's wheels, and who knows, it might be an issue with Opportunity. Someone mentioned that 1) Opportunity has endured a lot more cold nights than Spirit due to its deep-sleep mode at night, and 2) it did a lot of IDD work in Endurance. Just during the trip down the slope into the crater, it made a lot of RAT holes.

[Toma B]

Weeelll....
Even if they find a way to fix IDD arm I guess it will not be used as much as before...
Maybe they will be gratefull to "Lady Fortuna" that IDD stoped working while stowed because this way they can still do some science with Opportunity...
BTW does anybody knows how much times IDD has been "Stowed-Unstowed"? (100 times or so?)

[RNeuhaus]

One solution might be good is that Oppy try to approach to the Mogollon rim where there is somewhat hard wall (aprox 1.6 meter tall). So Oppy must go with its own forward traction and put its arm against the wall and at the same time, turn on the motor to try to retract it.

That is the additional help force from the wheels tractionn to permit in overcoming the initial hardest friction to retract to a safe position before roving. After that, I don't think that IDD might be useful anymore.

The cold weather leads to wear sooner the lubrication. A good leason is to design wheels and movil parts not be so dependent of lubrication by using small diamond balls with some synthetic lubrication that can last thousands kilometers and can tolerate a very low temperature with a very low "W").

Rodolfo

[Bill Harris]

News update:

http://www.jpl.nasa.gov/missions/mer/daily.cfm#Opportunity

--Bill


Latest Opportunity Update
Stalled Motor, Stowed Arm
Opportunity Status for sol 649-660
Release Date: 12/1/05

Opportunity drove 43 meters on sol 649 (Nov. 20, 2005) and then bumped 10 meters to an outcrop for work with its robotic arm (instrument deployment device) over the Thanksgiving holidays. Opportunity's commands for sol 654 (Nov. 25, 2005) included unstowing the arm to begin using the tools on it for examining the layered outcrop that the rover had driven to three sols earlier. The arm is always stowed during drives. This time, a shoulder-joint motor that is needed for unstowing the arm stalled, and the arm stayed stowed. In subsequent sols, engineers worked to narrow the range of possibilities for the cause of the stall. Among the remaining possibilities is that, after working more than seven times longer than originally planned, the lubrication is degrading. One possible fix would be to increase the duration of the allowed motor start-up, to overcome the increased initial friction. The first diagnostic activity for the arm was performed sol 659, where a very small motion was recorded. Future diagnostic activities and continuing analysis will be performed to further characterize the shoulder-joint motor in upcoming sols.

As of sol 659 (Nov. 30, 2005), Opportunity has driven 6,502 meters (4.04 miles).

[SigurRosFan]

Bill: Note Toma's post (#46)

http://www.unmannedspaceflight.com/index.p...indpost&p=29540

[Reckless]

Hi Guys
I don't know if it's just a coincidence but the last time both rovers successfully used their microscopic imagers was on the same day 26th November(at least that is when images came down on exploratorium)
maybe some new stowing sequence delivered to both rovers about that date could have caused the problem?
Any ideas?

Reckless

[djellison]

An MI healthcheck image has been scheduled for Spirit on the pancam traking site for a couple of sols - so I wouldnt read anything into it - I think it might well be a comparison image to go "right,we know spirit's IDD is parked, what does the IDD show there....now what does the oppy image look like...." as a secondary visual gauge of the IDD's exact position - probably down to a sub millimeter accuracy I would imagine. Then - they'll be able to either

a) Set off in the knowledge that the IDD is properly parked and work on the issue while coveirng ground

or

Know they need to fix the issue right now as it isnt parked and thus they cant drive

Comparing the two
http://qt.exploratorium.edu/mars/spirit/mi...W6P2900M1M1.JPG
http://qt.exploratorium.edu/mars/opportuni...KCP2900M1M1.JPG

It's clear that Oppy's IDD isnt parked in the same position as Spirit's - and thus it may be that it's not parked at all, or it's parked 'enough' to allow driving

That's my take on it all anyway.
Doug