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Solfe
2013-Oct-04, 12:20 PM
Recently, a hole was noticed in one of Curiosity's wheels. (Business Insider article with images (http://www.businessinsider.com/hole-in-mars-curiosity-rover-wheel-2013-10)) The hole looks "relatively largish" (very scientific, eh?) to me, which is odd for a vehicle that doesn't move very fast. Could landing punched this hole and we only noticed recently?

How big around are the wheels? I am thinking knee high (again, very accurate, eh?), but if they are smaller then the hole is very small.

One last question - Curiosity is pretty dirty. Has she encountered any dust clearing winds like the other rovers? I know that isn't really mission helpful, but she looks better clean.

Gemini
2013-Oct-06, 10:50 PM
Curiosity's wheel are 20 inches in diameter.

Trebuchet
2013-Oct-07, 02:41 PM
I was surprised how thin the metal is -- 0.75mm or 0.03in.

novaderrik
2013-Oct-11, 04:57 AM
that page (and the link to the blog on that page) says that the Curiosity doesn't "roll" on it's wheels, and that it would move around just fine without them...

if that's the case, then why did they put wheels on it? a crawling rover would be much cooler and get more mainstream attention...

Jeff Root
2013-Oct-11, 06:50 PM
My take on it is simply that the wheels have to rotate, they
just don't need to be round. Non-round wheels on a car would
give an unacceptably horrible ride, but they should work. On
Curiosity they might be just fine.

-- Jeff, in Minneapolis

ravens_cry
2013-Oct-12, 03:53 PM
I guess we can cancel that call to call MAA for a tow.

samkent
2013-Oct-14, 05:10 PM
OK I'm late to this party but I think the OPs link has made a worng conclusion.

Looking at the pictures:
If that's a hole why do we not see 'brown' through it?
It's bright white. Is the dirt bright white around it?

That metal looks too thick to poke a hole like that.

BetaDust
2013-Oct-14, 08:54 PM
Here (http://www.unmannedspaceflight.com/index.php?showtopic=7658) is a great thread over on UMSF (http://www.unmannedspaceflight.com/index.php?) about the status of Curiosity's wheels.

There also is a map (http://www.unmannedspaceflight.com/index.php?showtopic=7442) there showing curiosity's day by day drives and distances driven.
And she seems to doing just fine.

As long as she's roving and going where the MSL team wants it to go, I'm not going to worry much.


-- Dennis

Nicolas
2013-Oct-15, 07:35 AM
OK I'm late to this party but I think the OPs link has made a worng conclusion.

Looking at the pictures:
If that's a hole why do we not see 'brown' through it?
It's bright white. Is the dirt bright white around it?

That metal looks too thick to poke a hole like that.

http://static4.businessinsider.com/image/524d868ceab8ead70f02bf6d-1200-1200/curiosity-wheel-hole.jpg

I don't know which picture you're looking at, but I (and so does Lady Emily and NASA) see a clearly torn wheel with brown dirt visible right where you'd expect it. The bright white is just a highlight of the torn aluminum, much smaller than the actual tear. The tear fills the entire red circle in the picture linked above. The aluminium there is only 0.75mm thick.

That said, as long as the structural integrity of the wheel isn't compromised by the tear (which looks like it isn't the case at that spot), this hole seems harmless. I mean, there's intended holes right next to it and no parts sticking outside.

Jeff Root
2013-Oct-15, 08:23 AM
Nicolas,

I think your description is sufficiently far off that it might
not help samkent.

The tear doesn't fill the red circle, but maybe 15% of it.
A rectangular flap, seen obliquely so that it looks like a
parallelogram, still connected along the short near end
with the rest of the wheel material, and lifted up enough
to show a triangle of brown ground through the hole.
It is apparently also lifted up (pushed in) to the right of
the visible hole, so the area affected takes up maybe
30-40% of the red circle.

The material surrounding the intentional holes is *much*
thicker than the material of most of the wheel, to prevent
that area from being weaker.

I can only wildly speculate that the bright white spot is
caused by a tiny area of the aluminum being deformed
into a concave paraboloid-like surface which happens to
reflect the sunlight back toward the camera.

-- Jeff, in Minneapolis

.

Nicolas
2013-Oct-15, 08:39 AM
With my eyes, the tear goes over 75% of the diameter of the red circle. The rectangular flap you mention is less than half of the diameter, but the actual tear goes all the way up to the sand inside the wheel.

The intentional holes are surrounded by ridges (http://modemworld.files.wordpress.com/2012/08/msl-2.jpg) of thick material for traction and strength, as are the "profile ridges" (track) on the tire. Where there are no ridges, the material is very thin. It's in these thin flat spots that the tear occured, as was anticipated during engineering.

Oh yeah, nerd mode: the intentional holes spell "JPL" in Morse code. They are there to get the sand out of the wheel, to visualise wheel rotations, and to spell JPL over and over and over again all over Mars.

With the added tear, it now spells "JPL beep". :)

Jeff Root
2013-Oct-15, 08:45 AM
Oh, certainly over 75% of the diameter! Just not that much
of the area!

I edited my post to mention the affected area to the right
of the visible hole between the time you read my post and
the time you replied. :)

-- Jeff, in Minneapolis

Nicolas
2013-Oct-15, 08:53 AM
Oh, certainly over 75% of the diameter! Just not that much
of the area!

You always think in a higher dimension than me...

Sticks
2013-Oct-18, 05:36 PM
I have renamed the thread title to Hole in Curiosity's Wheel

Jeff Root
2013-Oct-18, 05:47 PM
Thank you, Sticks.

For those reading this thread in 2024, the title was originally
"Hole is Curiosity's Wheel", which was intriguing but annoying.

-- Jeff, in Minneapolis

Solfe
2013-Oct-18, 09:58 PM
Thank you, Sticks.

For those reading this thread in 2024, the title was originally
"Hole is Curiosity's Wheel", which was intriguing but annoying.

-- Jeff, in Minneapolis

It is more annoying when you are the op.

Thanks for fixing it, Sticks.