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View Full Version : Holy Wheels, Sharp Rocks Force NASA’s Curiosity rover to Seek Smoother Pathway to Mou



Fraser
2014-Feb-02, 06:40 PM
Continuing wheel damage from hoards of sharp edged Martian rocks are forcing engineers to seek a smoother pathway forward – potentially through a treacherous dune field – for NASA’s Curiosity rover on the jagged rock strewn road to Mount Sharp, her primary science destination. Ever since rover engineers noticed holes and tears to the robots […]

More... (http://www.universetoday.com/108808/holy-wheels-sharp-rocks-force-nasas-curiosity-rover-to-seek-smoother-pathway-to-mount-sharp/)

moose1950
2014-Feb-03, 01:55 AM
What is that tire made out of? It looks like some kind of flimsy cheap slippery plastic. It looks thinner and weaker than most of the doodads I buy at the Walmart come wrapped in. It looks different in the three top photos, but in the close up photo it looks shiny.

schlaugh
2014-Feb-03, 02:08 AM
The wheels are made of aluminum. http://www.businessinsider.com/rough-terrain-is-damaging-curiosity-rovers-wheels-2013-12


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moose1950
2014-Feb-03, 02:18 AM
It looks more like a brittle plastic than metal to me. Look at it in the closeup. Look at how it cracked, and the striations in it. They didn't expect rough terrain? Say what? What did they expect, a paved road? Each wheel is supporting 133 pounds Martian weight (330 pound Earth weight). Compare that with the bicycle tires you'd use to support a huge man on rough terrain. Google mountain bike tires. You can't make mountain bike tires out of some thin brittle material. Something doesn't compute here.

cjameshuff
2014-Feb-03, 03:05 AM
It's not a mountain bike. Mountain bike tires aren't suitable because of their mass and material issues, and aren't needed because of the low speed of the rover. You can't fix a flat tire on Mars, normal tire materials aren't made for the temperatures, solar UV, near vacuum, and sterilization requirements, and mass you spend on the wheels is mass you don't have available for instruments.

They wheels are aluminum. With some kind of coating, but that's been scratched away in many places, leaving shiny aluminum clearly exposed. The metal's thin because sending mass to Mars is expensive, and thin aluminum is subject to punctures and tearing. They expected to take some damage, and the wheels can continue to function as wheels even when full of holes. However, if they're altering course to reduce wear and tear on the wheels, they probably went overboard with optimizing for mass.

moose1950
2014-Feb-03, 03:20 AM
No, of course I didn't mean that they should have been using regular pneumatic mountain bike tires. I was just trying to illustrate the strength and resiliency of a tire that would normally be expected to support well over 100 lbs. per tire on rough terrain. And why do the tires have a rugged matte appearance, except in the closeup photo at the bottom where they appear to be made of a different material, shiny and plastic?

AGN Fuel
2014-Feb-08, 09:26 PM
No, of course I didn't mean that they should have been using regular pneumatic mountain bike tires. I was just trying to illustrate the strength and resiliency of a tire that would normally be expected to support well over 100 lbs. per tire on rough terrain. And why do the tires have a rugged matte appearance, except in the closeup photo at the bottom where they appear to be made of a different material, shiny and plastic?

The photos are taken from different angles (and by different cameras, with different resolutions). The "closeup" photo is clearly reflecting sunlight from the damaged aluminium surface, whereas the other photographs are taken at an angle with no directly reflected sunlight.