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Unmanned Spaceflight.com > Mars & Missions > Past and Future > MER > Spirit
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alan
CODE
01933 p2131.07 1   0   0   0   0   1    pancam_left_middle_wheel_R2
01933 p2131.07 1   0   0   0   0   1    pancam_left_middle_wheel_R2
01933 p2131.07 1   0   0   0   0   1    pancam_left_middle_wheel_R2
01933 p2131.07 1   0   0   0   0   1    pancam_left_middle_wheel_R2

16 of these taken yestersol

How far are they trying to turn the left middle wheel this time?
RoverDriver
QUOTE (alan @ Jun 11 2009, 10:53 AM) *
...

How far are they trying to turn the left middle wheel this time?


After some testing in the sandbox, I verified that larger wheel motion should not have caused much additional sinkage of the LM wheel. On Sol 1933 we commanded one full wheel revolution backwards and one full wheel revolution forwards. No LM wheel stall and wheel currents and other telemetry is all nominal. Also, from the rover attitude and suspension, we can see that the LM wheel did not sink. This is good news not only because it verified that the LM actuator is working correctly, it also validates that the soil simulant we have is a good representation of the soil on Mars.

Paolo
Stu
Astro0 and I have collaborated on a new poster/poem, inspired by Spirit's current predicament and the view she currently has. It's up on Astro0's website, and we hope you - well, some of you! - like it! As usual Astro0's graphics skills are sensational. smile.gif

http://astro0.wordpress.com/posters

centsworth_II
Beautiful poem, but I envision Spirit as speaking in a less flowery voice, perhaps that of Mark Twain:

“The rumors of my death have been greatly exaggerated.” laugh.gif
BrianL
I see Spirit in a bit more of an ornery mood:

"Hello, can we get on with this? My RF leg is cramping, and that rock under me is becoming a real pain in the... WEB". biggrin.gif
MahFL
Nice poem..... but a wheel has already turned.
Stu
QUOTE (MahFL @ Jun 12 2009, 03:43 PM) *
Nice poem..... but a wheel has already turned.


Thanks smile.gif the wheel hadn't turned when it was written, BTW.
MahFL
Well I realise that....still good work though.
nprev
Wonderfully written (Stu) & rendered (Astro0). That's an extremely evocative collaboration.
eoincampbell
Is Spirit looking at us shine the brightest and then our outer gaseous neighbors, in this beautiful depiction?
WOW!
Ta very much.
Astro0
Venus above...Earth below.

OK everyone...back on topic now. wink.gif
HughFromAlice
QUOTE (RoverDriver @ Jun 12 2009, 11:42 AM) *
.... from the rover attitude and suspension, we can see that the LM wheel did not sink. This is good news .....
Paolo


Here's a couple of gif movies from the D drive sequence (10 frames - backwards?) and E Drive sequence (6 frames - forwards?) on sol 1933.

EDIT - In the light of ROVR DRV comments see re-edited movies a few posts below

Click to view attachment Click to view attachment

According to the spacecraft clock 11' 01" elapsed between D drive jpg frame 1 and jpg 10 and 6' 26" between E drive jpg 1 and jpg 6.

With no movement at all and regular time interval camera shots taken, would expect a completely smooth movement of the shadow from upper right to lower left. Although it doesn't look (to my amateur eyes) like the wheel sunk at all, in the D drive movie the shadow seems to move slightly away from us - out of its expected trajectory - between frames 2 and 3 and again v slightly between 4 and 5 then continue on its expected trajectory. (Becomes obvious by placing a ruler 'scientifically' against your screen parallel v near to top horizontal line of rectangle of light in shadow on wheel and checking each frame!!). Is there a possibility that we may have actually got some traction here?
Burmese
What kind of analysis has been done so far with regard to the vulnerability of the WEB to that rock(assuming it is, in fact, a solid rock).

On a related note, while JPL can simulate the -visible- situation that Spirit is in, to what degree, if any can they anticipate or compensate for the problem of the rocks as they are beneath the visible surface. A wheel might either get stymied, or get traction from, a rock we can't see,; or can only partially see now. There are a lot of icebergs beneath the surface where Spirit is now, it seems to me.
RoverDriver
QUOTE (Burmese @ Jun 13 2009, 11:03 AM) *
What kind of analysis has been done so far with regard to the vulnerability of the WEB to that rock(assuming it is, in fact, a solid rock).


I think this was answered before.

QUOTE
On a related note, while JPL can simulate the -visible- situation that Spirit is in, to what degree, if any can they anticipate or compensate for the problem of the rocks as they are beneath the visible surface. A wheel might either get stymied, or get traction from, a rock we can't see,; or can only partially see now. There are a lot of icebergs beneath the surface where Spirit is now, it seems to me.


I will test what I can see, either from imaging and telemetry. I cannot simulate what I cannot see. Rocks, if they are small they do not affect traction significantly, if they are large they can either be a hazard (potato in the wheel) or an advantage (providing additional traction). If they are a hazard, the rover will tell me, and since I can't see them, there is nothing I can do to prevent them from becoming a hazard. If they provide additional traction, I would joyfully read the telemetry and move on.

In short, I cannot be ready for unknown hazards (and the rocks that are in this area I'm afraid are probably too small to provide additional traction). It is not that I am oblivious to it, it is that this is a risk that I have to take and cannot avoid.

If you have a constructive suggestion, I'm all ears. Really!

Paolo
RoverDriver
QUOTE (HughFromAlice @ Jun 13 2009, 02:03 AM) *
Here's a couple of gif movies from the D drive sequence (10 frames - backwards?) and E Drive sequence (6 frames - forwards?) on sol 1933.


It actually was 1 before, 7 backwards, 8 forwards. Each step was ~52/deg. I wanted to see where the tie-down cleat was in relation to the LM stall event on Sol 1899. I needed steps that were large enough to cover one full wheel revolution in a few steps, but small enough for me to see the tie-down cleat in one of the Pancam images.

QUOTE
...
Although it doesn't look (to my amateur eyes) like the wheel sunk at all,


You have good eyes. The telmetry shows no appreciable sinkage. This was verified in the sandbox prior to sending the commands on Mars. This also validates the soil we have in the sandbox.

QUOTE
...
Is there a possibility that we may have actually got some traction here?


One can always hope! smile.gif If the impediment that stalled the LM wheel on Sol 1899 was not inside the wheel well, it could be large enough to provide additional traction. That would be good. *Really* good. "Tiramisu'" good.

Paolo
HughFromAlice
QUOTE (RoverDriver @ Jun 14 2009, 09:42 AM) *
It actually was 1 before, 7 backwards, 8 forwards. Each step was ~52/deg. I wanted to see where the tie-down cleat was in relation to the LM stall event on Sol 1899. I needed steps that were large enough to cover one full wheel revolution in a few steps, but small enough for me to see the tie-down cleat in one of the Pancam images.


I've re-edited the wheel movies.

......Movie 1 - 7 backwards frames. Click to view attachment ........Movie 2 - 8 forward frames. Click to view attachment

I thought I might have got it wrong as I thought that 10 frames backwards and 7 forwards might not add up! What threw me was that the final 2 jpgs which I had edited into Movie 1 (backwards) were the last 2 of the D Drive sequence according to the MER file names and so it seemed logical they were the last two of a sequence. But what I should have done is to put these 2 jpgs in front of the 6 E Drive jpgs to make up Movie 2 (forwards)! I obviously haven't been able to relate the way the drive sequences are labelled in the file names to the reality on the ground - Before, backwards and forwards. If you - or anyone else - have time to answer, what did I miss?

Let's hope it IS Tiramasu!!!
CosmicRocker
For me, all of your animated GIFs go through one cycle and then stop on a blank frame. I'm not an expert, but I thought animated GIFs had a setting that instructed the sequence to "run once," or to "repeat." Are these animations cycling for others?
alan
QUOTE (Burmese @ Jun 13 2009, 01:03 PM) *
What kind of analysis has been done so far with regard to the vulnerability of the WEB to that rock(assuming it is, in fact, a solid rock).

IIRC the WEB will support Spirit's weight and even if a rock did puncture the WEB there is an inch of space between it and anything that would be vulnerable.
HughFromAlice
QUOTE (CosmicRocker @ Jun 14 2009, 03:40 PM) *
For me, all of your animated GIFs go through one cycle


Thanks for comment - you're right! Mainly because I often find it confusing and feel rushed when animated gifs recycle to the start without a pause - even get lost as to where the start is (especially animations like these wheel turns) - so, when doing for myself, I usually add a blank frame in at the end as a marker and only sometimes activate recycle. I did this for myself and then decided to post. Next time I'll add a blank frame and recycle!!
Astro0
This is just so nice, it'd be a shame not to share it smile.gif
Click to view attachment
Oersted
QUOTE (RoverDriver @ Jun 14 2009, 02:12 AM) *
That would be good. *Really* good. "Tiramisu'" good.
Paolo


Yes, especially since tiramisu' means "lift me up"... We could use some of that!
ilbasso
QUOTE (Astro0 @ Jun 14 2009, 04:12 AM) *
This is just so nice, it'd be a shame not to share it smile.gif


Beautiful! It's interesting to note the very deep pile of dust to the left of the mast. I assume that was on the lee side of the mast during the 'cleaning events.'
JayB
QUOTE (ilbasso @ Jun 14 2009, 08:58 AM) *
Beautiful! It's interesting to note the very deep pile of dust to the left of the mast. I assume that was on the lee side of the mast during the 'cleaning events.'


to me what's even more amazing is the dust pile probably reflects the condition of the whole panel array just a short time ago...
Oersted
Yes, just look at the solar panels over on the left side in this beautiful image. Lots of dust still left there.
erpol
QUOTE (Oersted @ Jun 14 2009, 11:20 AM) *
Yes, especially since tiramisu' means "lift me up"... We could use some of that!


Well.. That's the literal meaning..
But.. do *you* (in the USA) really know what a "tiramisu" is?? (yep, no apostrophe)

It's a sweet, sweet, sweet sweetness. tongue.gif (this is the closest smiley for licking your lips)

Paolo, what is the translation for "pan di spagna"? wink.gif


Ciao,
Ermanno
RoverDriver
QUOTE (erpol @ Jun 14 2009, 11:33 PM) *
Well.. That's the literal meaning..
But.. do *you* (in the USA) really know what a "tiramisu" is?? (yep, no apostrophe)

It's a sweet, sweet, sweet sweetness. tongue.gif (this is the closest smiley for licking your lips)

Paolo, what is the translation for "pan di spagna"? wink.gif


Ciao,
Ermanno


Yes they do. Tiramisu is one of the few unadulterated Italian deserts you can eat in the USA. It is one of my favourite deserts. Pan di Spagna is translated as "Sponge Cake" but it does not pay justice to this delicious pastry base.

Now, can we go back to the topic at hand, please? smile.gif

Paolo
Oersted
QUOTE (erpol @ Jun 15 2009, 08:33 AM) *
Well.. That's the literal meaning..
But.. do *you* (in the USA) really know what a "tiramisu" is?? (yep, no apostrophe)


Certo che so cos'è il tiramisù! - ho vissuto quattro anni in Italia, a Firenze. E sono danese, non statunitense...

Yes, back on topic! smile.gif That terrain actually is a bit tiramisù-like, with the light brown coating over a sticky surface! wink.gif
Oersted
Alan Boyle of "Cosmic Log" reports from the sandbox, etc: http://cosmiclog.msnbc.msn.com/archive/200...15/1963818.aspx
Stu
Spirit really drove into some freaky stuff, didn't she..?

Click to view attachment
SpaceListener
Indeed it seems was a very old pond of mud. Hence, to explore Mars, almost everyday there are surprises.
JayB
QUOTE (Stu @ Jun 17 2009, 05:56 AM) *
Spirit really drove into some freaky stuff, didn't she..?


Can someone explain that for me... To my eyes that looks like the tracks were covered by an upwelling of liquid which caused a flow. I just fixed an underground sprinkler leak that looked almost exactly the same. I can't imagine wind creating a distinct edge "flow edge" like that...
Stu
Isn't it just lots of fine grained material that Spirit's scruffling whels sprayed back over its own tracks?
JayB
QUOTE (Stu @ Jun 17 2009, 07:34 AM) *
Isn't it just lots of fine grained material that Spirit's scruffling whels sprayed back over its own tracks?


I suppose it could be...but I didn't think the wheels could spin fast enough to "spray" anything...even in lower g.

I'm looking for a earlier comparison shot to see how it's changed (anyone?)
djellison
QUOTE (JayB @ Jun 17 2009, 03:27 PM) *
I can't imagine wind creating a distinct edge "flow edge" like that...


I don't think Stu meant spray, like mud out the back of a car in a muddy field. Just motion by churning of the wheels.

Just try churning really dry flour. It does things just like that. We've seen churning like this many times, with both rovers. There is no reason to suspect that there is any aqueous action involved.

Go and look at the FHAZ images over the past few months, you can see this pattern form as the driving took place. Ditto several times at Meridiani.
JayB
QUOTE (djellison @ Jun 17 2009, 07:41 AM) *
Just try churning really dry flour. It does things just like that. We've seen churning like this many times, with both rovers. There is no reason to suspect that there is any aqueous action involved.


Interesting ... I've seen the churned soil many times like in the top half of the image...but not like in the bottom half...where the soil is disturbed but flat.

and while it really does look like what you'd get from an liquid upwelling, I didn't expect it would -be- one wink.gif

I guess in a way it is an upwelling... but of dry, very light soil

Freaky stuff indeed

RoverDriver
For those of you that have a DE pool filter, get a container about 10"x10"x6". You need to have about 4" of DE in the box. Now fluff it up using your hands as if you were tossing a salad with tongs. Although DE is not toxic it will dry up your hands, so use gloves if you want. Once it is fluffed up, using one open hand try to move around in the DE slowly. You will see that the DE behaves almost like a liquid.

Paolo
BrianL
QUOTE (RoverDriver @ Jun 17 2009, 10:34 AM) *
For those of you that have a DE pool filter, ... Although DE is not toxic it will dry up your hands, so use gloves if you want.


I thought the pool filter stuff was the type that is harmful if inhaled. If so, a mask would also be recommended.
stevesliva
QUOTE (RoverDriver @ Jun 17 2009, 11:34 AM) *
Although DE is not toxic it will dry up your hands


Huh, I'm surprised that what's in your sandbox is hydrophilic.
centsworth_II
QUOTE (stevesliva @ Jun 17 2009, 02:55 PM) *
Huh, I'm surprised that what's in your sandbox is hydrophilic.
I'm confused as to the significance. Isn't most Mars dust probably "thirsty"?

As I understand it, the pool filter type DE is not what is in the "sandbox", but rather the food quality stuff. I don't know if that also dries hands. Probably the pool DE was referenced simply because more people are likely to have that around.
RoverDriver
QUOTE (BrianL @ Jun 17 2009, 11:11 AM) *
I thought the pool filter stuff was the type that is harmful if inhaled. If so, a mask would also be recommended.


Correct.

Paolo
RoverDriver
QUOTE (centsworth_II @ Jun 17 2009, 04:00 PM) *
I'm confused as to the significance. Isn't most Mars dust probably "thirsty"?

As I understand it, the pool filter type DE is not what is in the "sandbox", but rather the food quality stuff. I don't know if that also dries hands. Probably the pool DE was referenced simply because more people are likely to have that around.


Yes. Both the food grade and the pool grade will dry your skin. The food grade is also used as a natural insecticide because it absorbs it absorbs water and wax.

Paolo
bgarlick
I find it quite ironic that DE is being used as a simulant in the testbed:
When Spirit first encountered the bright white powdery soil near home plate that turned out to be about 90% pure silica, the first thing my dad said (Who was a geology professor for 35 years). "If one found that on Earth, the first thought would be 'Diatomatious' because one would think hydrothermal deposits would be more solid and not a fine powder".

Indeed, From Wikipedia:
"Diatomaceous earth (pronounced /ˌdaɪ.ətɵˌmeɪʃəs ˈɜrθ/) — also known as DE, TSS, diatomite, diahydro, kieselguhr, kieselgur, Celatom or celite — is a naturally occurring, soft, chalk-like sedimentary rock that is easily crumbled into a fine white to off-white powder. This powder has an abrasive feel, similar to pumice powder, and is very light, due to its high porosity. The typical chemical composition of diatomaceous earth is 86% silica, 5% sodium, 3% magnesium and 2% iron."

This is not to suggest that the soils around Home Plate are actually diatomatious, because that would imply the martian soil contained diatoms which are silica skeletons of aquatic life-forms. That is way too outlandish! :-)
serpens
QUOTE (bgarlick @ Jun 18 2009, 04:37 AM) *
This is not to suggest that the soils around Home Plate are actually diatomatious


I thought that the closest fit was siliceous sinter? But apparently in this incident Spirit has encountered a ferric sulphate deposit so the use of DE would be happenstance as it provides a close simulation of the deposit in Earth gravity.
RoverDriver
The reason we chose DE is because is a fine powder, it does not ignite and readily available. That was back in 2005 and today as well. The feel from the pool grade DE is different from the food grade. The first is more abrasive, the second one is more chalky. There is absolutely no evidence that the material on Mars is DE of course.

Paolo
stevesliva
QUOTE (centsworth_II @ Jun 17 2009, 08:00 PM) *
I'm confused as to the significance. Isn't most Mars dust probably "thirsty"?


Yes. I just would have guessed that in our humid atmosphere, the material used to simulate mars would not be sucking up water, because the properties wouldn't match martian dust. My thinking is that flour (hydrophilic as well) packs into a more cohesive brick in a humid atmosphere. I would be afraid that the packing caused by embedding on earth would be firmer that what's happening on Mars. I am not familiar with DE. Could be that with the right relative humidity, it's exactly what they need. If they have AC in the sandbox, the humidity might be controlled fairly well.
RoverDriver
QUOTE (stevesliva @ Jun 18 2009, 08:36 AM) *
Yes. I just would have guessed that in our humid atmosphere, the material used to simulate mars would not be sucking up water, because the properties wouldn't match martian dust. My thinking is that flour (hydrophilic as well) packs into a more cohesive brick in a humid atmosphere. I would be afraid that the packing caused by embedding on earth would be firmer that what's happening on Mars. I am not familiar with DE. Could be that with the right relative humidity, it's exactly what they need. If they have AC in the sandbox, the humidity might be controlled fairly well.


Ah, now I understand your concern. First of all we are in SoCal where humidity control is activated almost all year long ;-) second, the sandbox does have AC on all the time. Humidity control needs to be active in order to preserve the assets (rover, cables etc..). Typically the humidity level is around 30-40%. It is also important because we want to make sure each test can be compared with the other which might be run on different days with different outside temperature and RH values.

Paolo
MahFL
"Humidity control needs to be active in order to preserve the assets (rover, cables etc..). "

How long are you planning running the test rover ? 100 Million years ? On second thoughts if its like Florida the rover would be a rust bucket by now !
RoverDriver
QUOTE (MahFL @ Jun 18 2009, 10:21 AM) *
"Humidity control needs to be active in order to preserve the assets (rover, cables etc..). "

How long are you planning running the test rover ? 100 Million years ? On second thoughts if its like Florida the rover would be a rust bucket by now !


The testbed is sensitive to electrostatic discharge, so extremely low humidity is hazardous. High humidity levels can oxidize parts and restrict motion. 100 Million years? No, but it would be nice to have the SSTB running during the entire mission.

Paolo
tty
Low humidity has a very strong impact on the reliability of electronics (and on mechanical components too, as a matter of fact). The Swedish armed forces have decreased down-time and maintenance costs dramatically by keeping aircraft and vehicles in humidity-controlled environments when they are not in use.

Also I would imagine that MER electronivs were not constructed for long-term viability in humid conditions.
centsworth_II
QUOTE (RoverDriver @ Jun 18 2009, 02:17 PM) *
...it would be nice to have the SSTB running during the entire mission.

How ironic it would be if the housed and coddled test rover failed before the actual MERs on Mars! laugh.gif
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