I know the arm (IDD) on these rovers isn't as strong as the one on Phoenix but looking at how deeply buried the wheels are, Spirit is either going to need a push or the soil is going to have to harden up.
- Status
Mee_n_Mac":3dwifi9v said:
Hi Mee_n_Mac,
Very true. The IDD (Instrument Deployment Device) is not nearly as strong as the one on Mars Phoenix Lander (the Phoenix arm could have dragged Phoenix along & even had the strength to lift Phoenix & turn the lander over), but I think that if Spirit cannot be moved when the next attempt is made, then IMO, it would be worth risking the IDD to help push Spirit out of that dust trap.
IMO the push to Goddard & Von Braun IS a top priority once Spirit is out of that dust trap. Of course Spirit could still perform a valuable fixed lander mission, but I think, that the situatoin does not call for that.
Spirit is not grounded, so we know that nothing is pushing against Spirit's underside, but it is clear that the wheels are deeply buried in the soft regolith & even under Mars's 37.7% gravity, Spirit will be heavy in the dust. The IDD IMO should be used to help push Spirit out.
Andrew Brown.
Patience.3488":3h4x1skv said:
They have only just seen under the rover. Now the test bed can be set up to recreate the situation on Mars. Next come the test bed trials. Then, based on those results, trials on Mars. Then, based on those results, more test bed trials. Let's see how a few rounds of this work out before resorting to drastic means. And using the IDD as a lever is indeed drastic.
centsworth_II":qfuvsz7w said:Patience.3488":qfuvsz7w said:
They have only just seen under the rover. Now the test bed can be set up to recreate the situation on Mars. Next come the test bed trials. Then, based on those results, trials on Mars. Then, based on those results, more test bed trials. Let's see how a few rounds of this work out before resorting to drastic means. And using the IDD as a lever is indeed drastic.
Agreed. It should be a last resort as I'd tend to think the instruments (except for the RAT) might not fare so well. Still I think it should be an option on plate ... assuming it would help. But when stuck in sand on Earth you only get some many trials before you're hopelessly bogged down and in need of a tow .... that can't happen on Mars. And yes I'm sure the mission team is aware of this. Just offering up some points for discussion whilst we wait.
The RAT on Spirit is already done for. Those rocks in Gusev are a lot harder than those in Meridiani and the teeth are wore out. The brush may still be of use though.Mee_n_Mac":2iet7imx said:
centsworth_II":2wboj3li said:
Very true Centsworth.
Spirit's RAT has ground into very hard, robust volcanic basalts where as Oppy's RAT has ground into far softer sedimentary rocks.
The brush on Spirit apparently is still usable but the RAT as you say is worn out & knackered.
I know what Mee_n_Mac & myself proposed IS a last resort, but if Spirit is truly stuck, then using the IDD is the last chance saloon of getting Spirit out of the dusty regolith & perhaps get her on her way to Goddard & Von Braun.
Hi everyone.
Sol 1,925 MER A Spirit Microcopic Imager mosiac of the underbelly.
It looks like a pile of regolith, possibly churned up initially by Spirit does extend to the underbelly, but fortunately no rocks do.
Andrew Brown.
That would be great. You are being optimistic -- with reason, I hope. As far as I know, the MER team is not sure either way yet, rock or dirt. I have to admit, it sure looked like a rock to me, but I'll be very glad to be wrong!3488":2p5ijczh said:
On the other hand, even a rock at the center is better than being belly flat on the surface.
centsworth_II":yy764a6o said:
Very true Centsworth,
To me that looks like a pile of soft regolith, rather than a solid rock, though I could be wrong of course.
I wonder if it's possible to look at images prior to Spirit reaching that point to see if any pointy rocks were on Spirit's route.
Mars Pathfinder imaged loads in Ares Vallis, & Viking 2 in Utopia Planitia. Spirit has seen a few, particularly on the plains & a few during the first Winter location, but none IIRC during this part of her route. Once again, I could be wrong.
Andrew Brown.
A member of UMSF did that -- and was thanked by a rover driver for his help!3488":1bratis9 said:
http://www.unmannedspaceflight.com/index.php?s=&showtopic=5999&view=findpost&p=141393
Spirit Rover Predicament
I was viewing the image they took of the underbelly of the Spirit Rover located at:
http://www.space.com/news/090604-spirit-belly.html. In the image below, I blew up the area to see if it were a rock or merely a pile of sand. I inverted the image and removed any additional light that was interfering with the soil details. Myself, I would have to say that the texture of the area in question matched that of hard soil, not solid rock.
http://img269.imageshack.us/img269/5076/spiritunderbellynegativ.gif
I was viewing the image they took of the underbelly of the Spirit Rover located at:
http://www.space.com/news/090604-spirit-belly.html. In the image below, I blew up the area to see if it were a rock or merely a pile of sand. I inverted the image and removed any additional light that was interfering with the soil details. Myself, I would have to say that the texture of the area in question matched that of hard soil, not solid rock.
http://img269.imageshack.us/img269/5076/spiritunderbellynegativ.gif
I also believe how she can get free. Yes, I know there is a bunch of scientists working on this paradox and what would I know. Well, I have some experience with vehicles getting suck pretty deep, in mud mind you... but if it works for a car on earth, why not a rover on Mars. Looking at the way the soil is angled around the tires, I think a reverse the forward "S" turn maneuver would allow loose soil to be pushed into the tire holes by the forward side of the tire. If they can rock it back and forth a few times like this, the tires will fill the holes they are stuck in with soil freeing the rover. Plus the soil is very rocky, like bits of crushed stone throughout it, so this would be helpful for traction.
I think the best mode of transportation for a vehicle on a planet like Mars would in fact be a small hovercraft. That is it couldn't be used very well to measure close up soil samples, however it would be great for imaging the landscape.
I think the best mode of transportation for a vehicle on a planet like Mars would in fact be a small hovercraft. That is it couldn't be used very well to measure close up soil samples, however it would be great for imaging the landscape.
centsworth_II":i66fz9lb said:
Thank you very much Centsworth.
I wonder if the rock highlighted in the images posted on UMSF is too small & does not IMO look quite the right shape?
It's difficult to guage sizes between the rocks imaged using the NavCam verses the same rocks imaged using the MI.
To me, that pile still looks like a pile of loose regolith, but it is difficult to tell, seeing as it is in shade. If it was sunlit, it would be much easier to see what it was.
Andrew Brown.
Re: Spirit Rover Predicament
Hi TheOneRaven.
Love the negative image you have created. Do I have your permission to download it?
I agree that the lighting is not ideal, as I answered to Centsworth's very interesting post.
Also I agree, that to me, it still looks like a pile of regolith, not a solid rock, though of course, giving it more thought, that it could be a rock, buried in regolith churned up by Spirit's wheels.
In your latest post, you propose a hovercraft. I like that very much, but I can see a couple of problems.
1). The martian atmosphere is so thin, the density at the aeroid (martian equivalent of sea level, as of course Mars has no sea level), is the same as Earth's atmosphere is at 30 KM / 19 miles above sea level. Of course Spirit is below the aeroid with the landing site before the climb up the Columbia Hills being 1,910 metres below the aeroid (Oppy was 1,440 metres below & Phoenix Mars Lander approximately 3,800 metres below the aeroid), but even allowing fo being nearly 2 KM below the aeroid, that atmosphere is still not much denser than Earth's is at about 30 KM above sea level.
The hovercraft would have to be very light & have a massive fan to create enough downdraft to create the lift.
2). If the hovercraft could be made to work, the dust blown about would be horrendous. A tight heavy 'skirt' would have to be used to keep much of the dust at bay, but even then, with the surface in many places littered with rocks (look at both of the Viking Landers, Mars Pathfinder & MER A Spirit images in particular), that 'skirt' would not keep a seal against the surface.
Andrew Brown.
xXTheOneRavenXx":wimlam9v said:
Hi TheOneRaven.
Love the negative image you have created. Do I have your permission to download it?
I agree that the lighting is not ideal, as I answered to Centsworth's very interesting post.
Also I agree, that to me, it still looks like a pile of regolith, not a solid rock, though of course, giving it more thought, that it could be a rock, buried in regolith churned up by Spirit's wheels.
In your latest post, you propose a hovercraft. I like that very much, but I can see a couple of problems.
1). The martian atmosphere is so thin, the density at the aeroid (martian equivalent of sea level, as of course Mars has no sea level), is the same as Earth's atmosphere is at 30 KM / 19 miles above sea level. Of course Spirit is below the aeroid with the landing site before the climb up the Columbia Hills being 1,910 metres below the aeroid (Oppy was 1,440 metres below & Phoenix Mars Lander approximately 3,800 metres below the aeroid), but even allowing fo being nearly 2 KM below the aeroid, that atmosphere is still not much denser than Earth's is at about 30 KM above sea level.
The hovercraft would have to be very light & have a massive fan to create enough downdraft to create the lift.
2). If the hovercraft could be made to work, the dust blown about would be horrendous. A tight heavy 'skirt' would have to be used to keep much of the dust at bay, but even then, with the surface in many places littered with rocks (look at both of the Viking Landers, Mars Pathfinder & MER A Spirit images in particular), that 'skirt' would not keep a seal against the surface.
Andrew Brown.
centsworth_II":8gav01ia said:
Very funny Centsworth. :mrgreen: :mrgreen: :mrgreen:
I wonder if a low late afternoon Sun could illuminate it? :?:
Andrew Brown.
Re: Spirit Rover Predicament
All very good points Andrew. I really only proposed a solution for distant photography of the landscape. But your absolutely correct. It would have to be geared for the atmospheric difference. Maybe not a larger fan, but perhaps a more concentrated down force area.
3488":1zvk91rj said:xXTheOneRavenXx":1zvk91rj said:
3488":1zvk91rj said:
Hi there 3488, thank you for the compliment
3488":1zvk91rj said:
hhmmm, I still find the texture more soil looking. I tried light enhancement on the area before inverting it to a negative, and reducing other light sources that were blurring the image. But that was the best I could do. The pile seems more centered under the belly of the rover, away from were the wheels would have trekked. Suppose it is possible to still be a soil covered rock though. Of course it could be a naturally covered rock, hence why they thought it wouldn't affect the rover in the first place... IF they saw it.
3488":1zvk91rj said:
All very good points Andrew. I really only proposed a solution for distant photography of the landscape. But your absolutely correct. It would have to be geared for the atmospheric difference. Maybe not a larger fan, but perhaps a more concentrated down force area.
There is another alternative I thought of just now. If they decide to continue with a rover vehicle, then include additional but smaller folding wheels that can be deployed & extendable for such cases as this were the primary wheels can be lifted and the vehicle pushed slightly in one of two directions. I'm sure that after such a recovery, the vehicle would have to remain in one location to recharge as it would take some extensive amount of energy.
xXTheOneRavenXx":29w67hf7 said:
Simplicity, low mass, low volume, and reliability are always the key. The KIS principle. You also don't want to muh unbogging gear there is no mass for payload. As with terrestrial offroading it is better to avoid getting bogged in the first place.
Jon
lol, well avoiding getting stuck in the first place is always an idea. Maybe a small seismograph of sorts to detect soil density would be an idea.
Definitely more wheel surface area would help in these scenarios but of course there would have to be trade offs.
On a side note, I wonder if the engineers have ever considered wind sails on these types of explorers. Would there be enough wind on Mars at all? Dunno, just thinking out loud, so too speak.
On a side note, I wonder if the engineers have ever considered wind sails on these types of explorers. Would there be enough wind on Mars at all? Dunno, just thinking out loud, so too speak.
Can the robot arm be used to help unstick Spirit?
If all else fails, perhaps the robotic manipulator arm be pressed against the soil to lift up and leverage Spirit out of its wheel rut holes? Is it strong enough?
It seems to me that the tops of the modules at the end of the arm arm form a flat and rather broad surface area, and if the arm were placed top down against the soil, this should be good enough to be stable, and and the wide surface area should prevent the arm from sinking in as it lifts. Is the arm strong enough to lift Spirit up and sideways?
I know this is a lost-resort proposal, and it would likely contaminate the cameras/instruments at the end of the robot arm with soil...but if all other manuvers fail, could this be considered ?
If all else fails, perhaps the robotic manipulator arm be pressed against the soil to lift up and leverage Spirit out of its wheel rut holes? Is it strong enough?
It seems to me that the tops of the modules at the end of the arm arm form a flat and rather broad surface area, and if the arm were placed top down against the soil, this should be good enough to be stable, and and the wide surface area should prevent the arm from sinking in as it lifts. Is the arm strong enough to lift Spirit up and sideways?
I know this is a lost-resort proposal, and it would likely contaminate the cameras/instruments at the end of the robot arm with soil...but if all other manuvers fail, could this be considered ?
xXTheOneRavenXx":3keq6352 said:
The best way to test density is with a mechanical or radiometric denisometer mounded on a probe ahead of the vehicle.
Oh boy
Even with my primative Adobe Photoshop CS3, I am pretty certain that the object peaking beneath the underbelly of Spirit is NOT a rock, but merely a pile of dirt as it carries the same texture as the surrounding dirt. If you compare the NASA image and my negative, you can see the difference between the solidified rocky textures from those of the dirt. A rock would also either be pitted, or carry contour lines under the negitive lighting. lol, I thought the NASA boys would be able to do a bit more then what they have been with their image analysis. Com'on boys, get in the game
Another Rover Stuck... in California":14whx1ot said:
Even with my primative Adobe Photoshop CS3, I am pretty certain that the object peaking beneath the underbelly of Spirit is NOT a rock, but merely a pile of dirt as it carries the same texture as the surrounding dirt. If you compare the NASA image and my negative, you can see the difference between the solidified rocky textures from those of the dirt. A rock would also either be pitted, or carry contour lines under the negitive lighting. lol, I thought the NASA boys would be able to do a bit more then what they have been with their image analysis. Com'on boys, get in the game
Explain to me please.
Why we have rovers, not crawlers?
I can understand, that rovers may perform better on rough terrain. Probably. On the other hand, crawler wouldn't stuck like Spirit did.
What else?
Why we have rovers, not crawlers?
I can understand, that rovers may perform better on rough terrain. Probably. On the other hand, crawler wouldn't stuck like Spirit did.
What else?
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