Beyond 1000 sols, Spirit's 'to do' list for spring Options

[bigdipper]

Thinking positive here:

Assuming that Spirit makes it to SH spring. (my answered prayer)

With limited mobility, but plenty of power and a few working instruments
What work remains to be done in Meridiani and what are the priorities?

Return to homeplate/pitchers mound?
Slowly climb McCool?
Venture off into the unknown?

I figure we have a little more than 100 sols to plan.
Let the NASA engineers worry about EOM, while we plan for spring cleaning .

[centsworth_II]

The new software updates will allow for more dust devil movies, if Spirit can see them from the Inner Basin. The view from Husband Hill spoiled us as far as dust devil sighting goes! If dust devils form in the Inner Basin, I hope the software gives Spirit a shot at getting a spectacular dust devil close-up.

How well Spirit will be able to get around with its bad wheel remains to be seen. At least it should be able to get back to Home Plate for a closer look. But will a trip to the "distant" badlands ever be an option even if Spirit lasts through the summer?

I think a climb of McCool Hill which would have been interesting and useful during the winter, is not worth the challange with the bad wheel when so many other targets are available at ground level.

My own wish list? A look at the "far side" of Home Plate and a close look at "Pitcher's Mound". And hopefully the drivers will find Spirit's mobility sufficient for an attempt at reaching the Badlands. That would be asking a lot!

[CosmicRocker]

centsworth_II: Those are also my wishes exactly. I fear though, that the trek to the Promised Badlands will be quite a challenge for Spirit. But as an optimist I think she may yet again live up to her name and find the heart to brave the journey into another unknown.

[Phillip]

I would think the number one priority would be to position Spirit in a location where she is most likely to receive a "spring cleaning" from winds. If that occurs, then she may be able to strike out again towards scientifically interesting locales, even with a bum wheel. If not, I suspect her mobility (and remaining time with us) will be rather limited.

Assuming a spring cleaning occurs, I would be in favor of heading towards the promised lands -- however slow the progress may be. I still hold on to a glimmer of hope that Spirit will find lacustrine deposits and I would not use Spirit's precious remaining time to return to a previously visited locale that offered no evidence of them.

My humble 2 c

Phillip

[helvick]

I would think the number one priority would be to position Spirit in a location where she is most likely to receive a "spring cleaning" from winds.

I fear that she may not be going anywhere unless she gets at least one spring cleaning in this spot.

[djellison]

I agree - I think a climb of McCool hill would serve two purposes...
1. Science
but 2 - much more importantly - get some cleaning. It was on the western side of Husband hill that we got cleaned last time around, and I think if we're lucky, and if we can even get there...then the same should be true on the western side of McCool - heck, I wonder if some fairly primative CFD of the topography might help find particularly windy spots to really get the best chance of a good dust-down.

Doug

[helvick]

heck, I wonder if some fairly primative CFD of the topography might help find particularly windy spots to really get the best chance of a good dust-down.

It might be a long shot but if it improved the chance of a good cleaning event then it would be worth making every effort.The Sol 421\422 event returned spirit to 96% of her initial performance level from a low of about 58% three sols earlier. Right now she's at about 49% of which around 15-20% is due to the tilt so she's got an awful lot of dust to get cleaned off.

However without some cleaning to start with though she isn't going anywhere. Power is going to stay well below 300whr per Sol from now on without it and any move will drop that down to close to 200whr at least initially.

[climber]

heck, I wonder if some fairly primative CFD of the topography might help find particularly windy spots to really get the best chance of a good dust-down.
Doug

I think this could be a place of cleaning events near by :
http://www.unmannedspaceflight.com/index.php?showtopic=2246

PS : I mean the suggested DD path not the delta river

[bigdipper]

...primative CFD of the topography might help find particularly windy spots to really get the best chance of a good dust-down.
Doug

According to this:
http://powerweb.grc.nasa.gov/pvsee/publica...cpec2/dart.html

wind velocities above 35m/sec (126km/hr) are required for martian dust removal.

"5. Dust Removal And Abrasion by Wind
...experiments show that a wind velocity of at least 35 m/sec was required before significant amounts dust removal was achieved by wind. Measurements of surface winds was done at both Viking landing sites [14]. The daily peak wind was about 7 m/sec at Viking-1 site, and about 3.5 m/sec at the Viking-2 site. Winds over 15 m/sec occurred less than 1% of the time. Over 100 days of operation, the peak gust velocity observed at the Viking 1 site was of 25 m/sec. Thus, these experiments suggest that it is unlikely for significant amounts of dust to be cleared from the array surfaces by wind. However, it was observed by Viking that the light surface coating deposited on rocks after the major dust storms (attributed to fine dust coverings) disappeared with time, indicating removal of the dust layer by wind [15,16]. This indicates that it must be possible for some clearing of array surfaces to occur. Most likely, this clearing occurs by brief gusts of high wind. This is confirmed by the observation by Pathfinder of localized "dust devil" lifting of dust [17].
...
The wind velocity is believed to be higher on sloped terrain, and global meteorological models of Mars suggest that surface wind velocities near the Martian equator may be quite high."


Spirit is near the equator and on somewhat higher/sloped terrain so chances are slightly improved for a cleaning event (in the spring).

Are we absolutely sure "gust angels" are the only mechanism for cleaning?
http://www.unmannedspaceflight.com/index.p...ost&p=55502

"Adler also noted that there are advocates of a process whereby sublimation of CO2 ices lifted the dust off the panels. I was a bit incredulous over that one, but he insisted that it is being given serious consideration as a possible cleaning cause."

I haven't seen anything further on the CO2 sublimation mechanism. Any idea how that might work? Would it be more of a SH winter or SH spring phenomenon? Preferred locations? (Google didn't help any)

Looking at Helvick's Power Chart Spirt needs a cleaning event soon and needs to learn how to manage <280 whrs for 100-150 sols. (Thanks Helvick, great chart)

Newbie question - CFD=Computational Fluid Dynamics?

[djellison]

Yup - Comp Fluid Dynamics.

I'm not sure if CO2 type dust removal is more likely during the height of summer - but I think we can throw anything quantitaive out the window (i.e. X m/sec etc ) as we just do not know enough about how the mechanisms of dust removal work.

Qualitatively, we had huge dust removal when we were on the slopes of hills, during summer, on generally west facing slopes. Out best chance of more clenaing would surely be to replicate these conditions.

Doug

[CosmicRocker]

I agree that a cleaning is the highest priority, and that a wind cleaning is more likely than some other, more exotic mechanism. The only thing we know about Spirit's previous cleanings is that they occurred high in the hills and at times when wind appeared to be active, so going to a similar location makes sense. I'm just not sure Spirit can climb another major hill. We have other empirical information from Opportunity regarding panel cleaning. Opportunity hasn't climbed any significant hills, yet she enjoyed a cleaning or two while in or around Endurance Crater, iirc. That would suggest to me that abrupt topographic changes may play a role in inducing wind vortices that exceeded the threshold wind speed for dust removal.

As has been mentioned, we did see one dust devil apparently enter the basin, and we saw many dust devils and wider, dust-blowing wind gusts down on the plains. Those looked more like dust sheets or something. I went back to look at some orbital imagery for DD tracks. While not as common as on the Gusev plains, there are some tracks crossing the Promised Land, though they are harder to see. The erosive appearance of the badlands also suggests that winds may be effectively removing fine particulates there.

I think we need to be practical about Spirit's ability to move. Besides, there seems to be a broader array of new science to be had by staying below the ancient hills. Home Plate clearly begs for more study, Pitcher's Mound is still a bit of an enigma, and the Promised Land may be "who-knows what." You want to learn more about the history of H2O on Mars? In this area it seems obvious. Look lower rather than higher.

[climber]

That would suggest to me that abrupt topographic changes may play a role in inducing wind vortices that exceeded the threshold wind speed for dust removal.

Endurance has a rim "above" the flat terrain while Victoria is a kind of "hole" in the flat terrain. Do we have to run CFD to assess the winds in VC or is there evident differences ?

[centsworth_II]

If you'll all indulge some novice thoughts....

Could a mini-tes panorama be used to detect areas with less dust buildup, presumably due to wind removal? If such a spot could be detected, it could be the next stop as soon as Spirit can move again. Maybe just getting to the top of Low Ridge or Home Plate will be an adequate substitute for a mountain ridge.

Also, the mention CFD brings to mind the thought of winds winding through low areas, such as the path between Low Ridge and Home Plate. What are the odds of wind in that type of location as opposed to a high spot?

I'm reminded of ustrax's detailed (imaginary) maps showing flow paths into the "Ultreya Abyss". As it turns out, the abyss was the dark El Dorado dune field. Was the dark material transported there by winds winding down paths similar to those depicted by ustrax?

[CosmicRocker]

Endurance has a rim "above" the flat terrain while Victoria is a kind of "hole" in the flat terrain. ...

Climber: I am not sure what you mean. Victoria seems to rise well above the surrounding terrain.

For what it is worth with respect to Spirit, I understand that wind dynamics may be significantly different in Meridiani as compared to Gusev. But I looked back to see where Opportunity was when cleaning events were observed on that rover. Three out of four took place on the flat plains, though one could argure that there is some topography near Olympia.

CODE

sol 196-199     Deep within Endurance
sol 456         At Purgatory
sol 524-526     Just south of Purgatory
sol 638         Near Olympia

[bigdipper]

The latest Spirit Update from JPL/NASA looks upbeat as far as power is concerned (275 whrs minimum).

http://marsrovers.jpl.nasa.gov/mission/status.html

Did anyone else think the "Spirit clears away dust..." headline was intentionally misleading?
It refers to the RAT, not the solar panels. I really had my hopes up.

Helvick's new power charts are up in tech forum - with luck Spirit will live to see SH Spring.

Then what?