sol 2156 would be today?

http://www.giss.nasa.gov/tools/mars24/merclock.html

Yes.

now, THAT is a handy little gadget... Thanks!


Now here is a question -- if Spirit's arm was extended more towards the right, it would make a small, but maybe helpful, difference in the center of gravity towards the uphill side... Has this been considered?

Conference has started

http://www.nasa.gov/news/media/newsaudio/index.html

"It's driving days are likely over."

It looks like they're going to tilt the rover into the sand trap.

160 watt hours are estimated to be needed to maintain activities (contacting each day). Otherwise, hibernation (fault mode).

Electronics can handle being below -50° C when not operating, -40° C when operating, expected to get to -45° C in winter. It is expected Spirit will survive, but not guaranteed.

Remaining activities: get LR up to improve tilt (eastward tilt is preferred). Significant improvement on northerly tilt of 1 - 2° on last drive. Try to tilt the rover north-ward and/or east-ward.

Not as much as an emphasis on driving with only 4 working wheels, so stationary science will be emphasized. Ideas: Spirit being tracked to constrain Mars' spin axis wobble rate, giving insight into the planet's interior. They think they can do this in six months. Additionally, a stationary mission will enable them to watch how features there change due to wind, as well as watching how soil is stirred by wind as seen through the microscope. They'll be given an opportunity to better characterize the soil. With the limited mobility, they maybe can move around to reposition the rover to enable other science experiments.

Backwards drives will continue in the near term.

Curious "news" item.

Possible science come spring

Radio science to determine axial wobbles - Determine molten or solid core
Atmosphere and surface changes - Look at macroscopic and microscopic changes on the surface
Comprehensive soil characterization - this is a really strange set of soil. Not like normal Martian soil. Extremely rich in sulfate salts. Salts initially formed by fumaroles. After billions of years, other water processes caused salts to move around. Soluble salts had moved around. Moderately good picture of soil structure. Lots of time will allow much greater characterization. Expect to use wheels in spring to slightly reposition rover to reach new soil.

Bottom line: Not giving up on Spirit

You've got to hand it to Steve Squyres. I don't know anyone else who could sell a major reduction in Spirit's capabilities as a ground-breaking, exciting opportunity quite so effectively.

Here's the official press release

http://www.jpl.nasa.gov/news/news.cfm?release=2010-030

More info

http://www.nasa.gov/mission_pages/mer/news...el20100126.html

I'm hoping someone will ask if extraction attempts might continue in the spring. It sounded like the answer was "no", but it wasn't entirely clear. If it is "no", then exactly why considering the recent progress?

Edit: Emily asked! Squyres McCuistion said problem was basically that we have a four wheeled rover.

Well, we can still hope for an "accidental extrication."

But it sounds like this extrication thread's days are numbered.

Stroupe just talked about extraction attempts/4 wheeled driving being an option in the spring after the spring stationary science!!

Loss of RR is a big hit I guess. I would hope we see some 4 wheel drive testing on the flat in the ISIL just to see how much progress, if any, Spirit might make if extraction is reattempted and successful.

Well, assuming that Spirit survives the winter, there will eventually come a time where, no matter how interesting Troy is, there will be diminishing science returns, and they will turn their minds to other objectives. Even being able to drag itself a few meters over a couple of months would allow Spirit to reach new locations and more science to be done.

So, I suspect they will continue to work on various scenarios behind the scenes even if their official position is that Spirit is now a stationary platform. It's better to be realistic than to be overly optimistic.

A very interesting figure: Spirit gets about 5 or 6 Whrs/sol of extra power for every degree of extra northerly tilt.

Remember it's a cos(theta) issue though, as was mentioned, so that won't hold true for every value of theta.

Firewall at work won't allow audio streaming - so thanks to all for the text updates - hope someone can make an mp3 available later?

But for the sorts of figure we're talking about ( <10-15 degrees ) it holds pretty damn close.

That's a surprisingly large return per degree, actually...much more than I would have guessed.

Frankly, I'm looking forward to any seismology results. Wonder if any of these small impacts will be picked up; can't localize them (or can we? perhaps very approximately?), but it'd at least be interesting to see if we get some data re their frequency of occurence.

When I hear the "basicly we're running out of time" comments, I can't help but wonder what would have happened if they had started the extraction two months earlier. Sorry, but I still think those six months of sandbox testing was way too long.

I'd like to interview her for a position.
Don't mind either her coming to my place or me going there to meet her.

Was listening in. Assuming Extrication was even possible, it doesn't seem likely to start for a minimum of another year based on their plans. From what I understood..

1: Take the next month to get a better tilt
2: Ride out the low power for another 6 months, hope you have enough to not trip low power faults (limited science, observations and even communication)
3: Once enough power comes back, take another 6 months of observations to determine if core is solid or liquid.

Didn't get the exact total cost of MER's including everything. Was it 909 M$?

Indeed it won't. But if the tilt changes enough (10 or 20 degrees as Doug said) to change the figure I quoted significantly, then we're in great shape for the winter!

This is what I expected. Power is too low and only 4 wheels is not good for exctraction. Now we wait a while and we can see dust drifts forming etc . pics pics pics.

That leaves us with a mobility-challenged rover and a sand trap that looks very inviting as far as a tilt perspective. Spirit would go right back in and we'd currently be back where we are now, if not soon.

All other things being equal, I would think a westerly tilt is better than an easterly tilt, since the sky is open to the west but partly blocked by Home Plate on the east. However, by "easterly tilt" they probably mean less of a westerly tilt, not an actual tilt to the east.

Hindsight is 20/20.

hmmm after the progress made on the last couple of drives, i'm not sure I was quite expecting this news

I saw this coming...stupid emotions...
Here are my words for Spirit, my favourite rover:
http://beyondthecradle.wordpress.com/2010/...uest-our-quest/

They basically said they only had a handful of drives left (can't drive every day now) before power was too low for driving at all. They needed those drives to improve tilt.

I wonder what they would do if Spirit suddenly gained traction on a tilt setting drive and popped right out. Would they say...

Bad driver! Bad, Bad! You put that rover back where you found it this instant!

Well, I'm still hopeful there will be a change of heart in the spring, assuming the winter positioning doesn't make further movement impossible. I'm sorry, I'm just not a lander kind of guy.

Brian

Definitely the most exciting briefing in a long time. To me the central question was about the possibility of continuing extraction attempts in the spring. On the one hand we had the negative response to this from Squyres, as well as statements like this from the press release: On the other hand we had the mention of extraction attempts in the spring from Stroupe. So as tacitus wrote:it may be that scenarios are being kept open. It also may depend on what happens with the final drives of the season coming up. Let's hope for continued progress.

The thing that puzzles me most is, as Doug mentioned, we should have some testing with 4 wheels in the ISIL (at least I don't recall hearing of any such testing yet). If they knew we can't rove with 4 wheels, then why have we been doing extraction attempts (not tilt-improving drives) up to tosol, when the RR wheel died way back in November? I completely understand the need to settle in very soon now for the winter. But why not keep further extraction attempts an explicit goal come spring? What has changed now (rather than in November) that precludes that?

What we actually don't know is why they decided to reverse the drive (that ended up to be succesfull) and this could answer your question, fredk. I do not think they reverse "just to try and see what happen". So, the tilt correction could have started awhile ago?

If sandbox testing has shown that the only thing a 4-wheeled rover can do is pushing sand around in circles to the left, then the decision to become stationary makes a lot of sense. Are there any videos somewhere of driving with only four wheels?

Not according to what they've said. From this Spirit update:There've been other statements to the same effect.

Has the RR wheel been powered on since it got back up from being completely burried?

Can anybody please help me summarizing Spirit status?

Regardless of great improvements in Spirit position in sandtrap during last few days, due to very low power coming from low sun, it has been decided to stop any further attempt to get Spirit out of the sandtrap; power will be used instead to dig it deeper, in such a way its tilt will allow more sunlight to hit panels, thus providing enough power to (possibly) keep Spirit warm during martian winter, which starts in february and ends in may.
No further extrication attempts will be performed even after winter, when more power will be available, due to only 4 out of 6 wheels being now properly working.

Is this correct?

Which are the operating wheels right now?

It all boils down to "To dig or not to dig?" If they don't dig in the front wheels, they have a shot of extraction come spring. (Assuming she survives the winter.) If they dig in the front wheels, the chances of survival go up but the chances of extraction go down.

Also, if they choose not to dig they can use the 6+ months for more sandbox testing.

I would love to see further driving in spring too. But answering to your second question I think it's a result of the decision to start doing science only possible with a stationary lander. See, if you start an experiment which needs, say, minimum six months of data adquisition at a fixed place, you cannot start moving again before the other activity is finished.

In any case, Spirit's career is not finished by any means. If she survives the winter, and I believe the chances are good, we'll see once again the power levels going up and probably some of those cleaning events which boosted the power up to 900 Wh.

What a serious briefing. The good news is it sounds likely that Spirit can survive the winter even if she lapses into hiberbation. I'd still hope 8 months from now they can check the FR and RR wheels again to determine their status and then decide what science campaign to begin. Call me a foolish optimist, but even a rover that can only manage to limp along at 50cm per day could still explore some potentially interesting sites: South Promontory is only about 50m, and Von Braun another 80m beyond that, although I recall the slope would be more difficult than her last few drives before falling into Troy.

How long would the measurement campaign be for the radio-wave wobble experiment (is 6 months a minimum)? I can see measuring the core would be a huge priority, so maybe visiting further sulfate and silica deposits around Home Plate isn't worth the effort?

Maybe next (Martian) summer the solararrays will be covered in dust, and they will have no choice but to try driving again to survive the winter.

Not necessarily. First they'll continue with the backwards drives, to try lift the rear up. They may then try to dig the RF wheel in, to drop the front of the rover.No. Winter solstice is in May, so power will be lowest roughly symmetrically around that.That sounds like the official postition, but as I wrote Stroupe mentioned the posibility of further extrication attempts in the spring.

Good point. If they want a long-lived lander mission, it might be prudent to first find a better perch that would be favorable for all winter states.

I don't agree! We had the best cleaning events ever at this very place (because of venturi effect).

I don't think that it's a matter of wanting a stationary mission so much as that's the best available option with all situational constraints considered. After winter's over, new options may emerge.

Well said, I think. First thing's first: survival.

This is a good point. But still, surely whatever science that could be had if she were to be mobile again would supercede the iron core science. If she does manage to move some (even a small) distance to new targets in the spring, there's always the possibility for core science later.

I would love to know everything that went into today's announcement. I wonder if there may be another factor lurking in the background here. We know the next review is coming up rapidly in February. I wonder if they may have decided that they would be more likely to get another extension by proposing science that they know they can do with a stationary rover, rather than by proposing that they continue extraction in the spring and then, if they get out, to continue roving and doing the science that would allow.

I guess we'll find out 5 years from now.

Brian

That's a very smart guess. Being able to say "Here's new science we can't do with any other asset" sounds like a much stronger budgetary case than "We'll keep spending money and maybe we'll get somewhere eventually." I can't help but guess that this isn't universally popular among folks working on the mission; I'd love to know to what extent it's a deeply held position and to what extent it's a strategic move in hopes of getting mobile at a later date.

In any event, a live station is more interesting than a dead rover.