Curiosity's Wheels

[RuBisCO]

Not looking too good in latest selfy:

http://mars.nasa.gov/msl/imgs/2015/08/mars-curiosity-rover-msl-horizon-sky-self-portrait-PIA19808-full.jpg

How long will curiosities wheels last?

Clearly the next rover needs a wheel re-design, but what exactly can be done to improve the wheel's strength while retaining light weight?

[Nibb31]

The wheels are in bad shape, but it its the horizontal tread parts that do all the traction. The flat areas that are damaged aren't structural, they just prevent the treads from sinking into the sand. As long as they stick to solid ground, the rover should be fine.

Mars 2020 will be based on the same design as Curiosity using leftover parts, but with new instruments and different mission goals. They have planned to redesign the wheel assembly.

[Camacha]

The wheels look pretty good. I remember some images made quite a while back and the holes that can be seen now were pretty much all there back then. It at least means the problem is not worsening very rapidly.

What can be done without adding much weight? Not much, it really needs a bit more substance to be more robust. Curiosity was engineered for the then known circumstances. By now we know Mars can be a bit nastier on wheels than we expected before due to the ground being more irregular than observed earlier, so the wheels will need to be beefed up a bit.

When taken into account pretty much from the start, it should not be any sort of issue. You add a couple of kilos, but you can easily adapt the transfer and support structure accordingly. Maybe even other optimisations can be made to the vehicle that the total weight remains the same.

[LordFerret]

It says 'selfie' ... but what is taking the picture? I don't see any outstretched arm from the rover. And it's sitting on a little hill; Whatever is taking the picture is standing on what appears to be a pretty steep slope.

So, tell me a little more about this shot.

[Brotoro]

I see shadows of an outstretched arm that has obviously be removed.

[Frida Space]

It says 'selfie' ... but what is taking the picture? I don't see any outstretched arm from the rover. And it's sitting on a little hill; Whatever is taking the picture is standing on what appears to be a pretty steep slope.

So, tell me a little more about this shot.

It's actually a mosaic, they managed to stitch together the images to cover more than half of the robotic arm and make it "invisible".

[Nibb31]

It's a composite shot made from multiple photos taken with the arm in different positions. When compositing the image, they only take the parts of the picture that don't have the arm in it.

The blurry white thing on the bottom of the picture is the part of the arm that couldn't be covered up by another picture.

Edited August 20, 2015 by Nibb31

[Camacha]

It says 'selfie' ... but what is taking the picture? I don't see any outstretched arm from the rover. And it's sitting on a little hill; Whatever is taking the picture is standing on what appears to be a pretty steep slope.

So, tell me a little more about this shot.

It is a composite shot, as can be seen by the shadows. Because of this, the arm seems to 'disappear'.

[LordFerret]

Saw the shadow, but wasn't going to assume.

[Mazon Del]

This is actually one of their "worse" selfies in a way. You can see the jagged part of the arm in the upper right part of Curiosity where the mosaic cut if off.

[CalculusWarrior]

The blurry white thing on the bottom of the picture is the part of the arm that couldn't be covered up by another picture.

That actually looks more like dirt from a hole Curiosity dug that's been blown towards the rover (hence the clear ground behind rocks).

[kiwi1960]

I wished people would use the tags... then the photo would display without our needing to right click on the link and 'open in new window' or tab....

But oh well.... Mars is the only planet we know about inhabited entirely by robots....

Edited August 20, 2015 by kiwi1960

[grawl]

The "holes" look like to me they were intended to be there.

They seem to be part of the wheel, maybe to handle different kind of terrain.

I wouldn't be surprised if they were engineered from the start.

What makes you thin Curiosity's wheels are in bad shape ? I feel like I'm blind here.

Edit:

Tried to post the tag, but the image is cropped out. Maybe a BB-fu option exists to resize it

Edited August 20, 2015 by grawl

[kiwi1960]

Yeah, saw that..... well.... OK, the OP has an excuse and is off the hook.

[AngelLestat]

lovely picture, one of the best pictures that I saw from Mars.

It has great quality and we can see the rover, which give us a sense of scale.

[Camacha]

The "holes" look like to me they were intended to be there.

They seem to be part of the wheel, maybe to handle different kind of terrain.

I think you are referring to the morse code. The holes represent the letters J P L in morse code, which is of course the Jet Propulsion Lab. This is partly because it is a neat homage to the guys building the thing, but the tracks those holes create actually help determining distance and distance calibration.

The holes we are talking about are actual holes and tears.

JPL morse code:

Actual damage:

Edited August 21, 2015 by Camacha

[Darren9]

I was expecting them to be not round any-more or half falling off after reading the OP, they don't look anywhere close to actually failing.

[Camacha]

I was expecting them to be not round any-more or half falling off after reading the OP, they don't look anywhere close to actually failing.

The MSL team is very aware of the fragility of the rover's wheel, deliberately and carefully choosing paths through less damaging parts of the Martian soil. Only if the potential science yield is worth it, they will allow further damage. It is an issue that can be management, but also one that would ideally not hamper your mission at all.

[andrewas]

The "holes" look like to me they were intended to be there.

They seem to be part of the wheel, maybe to handle different kind of terrain.

You're looking at the neat square holes, which were deliberately included in the design. But if you look closer, you'll see the damage. On the front left wheel, there's a hole above the square holes, and a visible hole on the back side of the wheel. The damage may not seem all that bad, but testing shows that the wheels will fail at less than half the rovers expected lifetime if they don't take care to avoid bad terrain and otherwise mitigate the damage. And losing even one wheel could kill the rover, the damaged metal can rub against the rovers cabling and cause a serious failure even if the wheel itself can still be driven on.

[Ralathon]

I was expecting them to be not round any-more or half falling off after reading the OP, they don't look anywhere close to actually failing.

Remember that they can't quickly pop over and replace the wheels. They want to keep this rover alive and rolling as long as possible. So if the wheels show visible damage after just 3 years that's a cause for major concern.

[RuBisCO]

I was expecting them to be not round any-more or half falling off after reading the OP, they don't look anywhere close to actually failing.

Oh come on!

kiwi1960,

I did not put it in a tag because unless you have a 4k monitor the full size image requires most people to zoom in.

[Camacha]

Remember that they can't quickly pop over and replace the wheels. They want to keep this rover alive and rolling as long as possible. So if the wheels show visible damage after just 3 years that's a cause for major concern.

We could always send in a wheel/tire changing robot.

[grawl]

I think you are referring to the morse code. The whole represent the letters J P L in morse code, which is of course the Jet Propulsion Lab. This is partly because it is a neat homage to the guys building the thing, but the tracks those holes create actually help determining distance and distance calibration.

The holes we are talking about are actual holes and tears.

JPL morse code:

http://www.collectspace.com/images/news-082212b-lg.jpg

Actual damage:

http://i.space.com/images/i/000/040/452/i02/curiosity-wheel-damage.jpg?1404866981

Thank you !

Now I see these little nasty cracks (not looking at a miniature is the trick ). The high res picture is quite impressive ! (much pixel, such wow !)

[softweir]

The blurry white thing on the bottom of the picture is the part of the arm that couldn't be covered up by another picture.

According to the BBC website, it's the scar where Curiosity drilled into the rock.

[cantab]

I think they'll just have to thicken the wheels a bit for the next one. Yes it will add some weight, but it's probably still not much compared to the whole rover, and can probably be saved elsewhere by using more modern lighter science equipment.

As for Curiosity, NASA just don't want to drive over any stones. Which is a bit of a problem on Mars.