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I found the wheel problems with Curiosity to be super interesting. They designed this incredible vehicle, and landed it in this incredible way, but making the w

by D13Fd 6y ago

I found the wheel problems with Curiosity to be super interesting. They designed this incredible vehicle, and landed it in this incredible way, but making the wheels just a tiny bit too thin (in a well-justified pursuit of optimization) wound up limiting the scope of the mission when met with unexpected terrain. It shows just how small of a margin of error they have in making this all work.

proactivesvcs 6y ago
I think it was Curiosity's wheel treads which spelled out "JPL" in Morse. Such a gloriously geeky Easter egg!
- ibrault 6y ago
  Yep! It was originally supposed to be the full logo but that got vetoed
bmitc 6y ago
I haven't read about this in a long time, but I have always been curious why the wheels weren't tested more on Earth and designed to be more hardy. Curiosity has apparently only traveled 12.5 miles, and that seems extremely low for such heavy damage. I would have guessed that tests on Earth would have logged many more miles than that, but I should look into their diagnosis of what went wrong.
- nickserv 6y ago
  The rovers were extensively tested on Earth. However, Mars has lower gravity than Earth, which would of course have an impact on the wear on the wheels. Maybe there was an underestimation when applying the lessons on Earth to Mars gravity?
- StephanTLavavej 6y ago
  https://www.planetary.org/articles/08190630-curiosity-wheel-damage https://www.planetary.org/articles/08190630-curiosity-wheel-... explains the root cause.
  - bmitc 6y ago
    Thanks for that link. I think I have read something similar in the distant past but read through it again. > There are [places] on Earth that do have these sharp ventifacts, but we hadn't seen them on Mars and we didn't test against them This is whats so curious. In their testing on Earth after the fact, they found: > Bedrock with lots of rocks: ~8 kilometers > Lots of rocks, not on bedrock: 13-14 kilometers > Bedrock with few rocks (think flagstones): 30-40 kilometers or more It's just very surprising they didn't think to test on more varied Earth terrains, looking for worst case scenarios, where they would have clearly found this limitation. It is my understanding that the wheel damage became a major limiting factor of Curiosity's mission.

by D13Fd 6y ago

proactivesvcs 6y ago

I think it was Curiosity's wheel treads which spelled out "JPL" in Morse. Such a gloriously geeky Easter egg!

ibrault 6y ago
Yep! It was originally supposed to be the full logo but that got vetoed

bmitc 6y ago

I haven't read about this in a long time, but I have always been curious why the wheels weren't tested more on Earth and designed to be more hardy. Curiosity has apparently only traveled 12.5 miles, and that seems extremely low for such heavy damage. I would have guessed that tests on Earth would have logged many more miles than that, but I should look into their diagnosis of what went wrong.

nickserv 6y ago
The rovers were extensively tested on Earth. However, Mars has lower gravity than Earth, which would of course have an impact on the wear on the wheels. Maybe there was an underestimation when applying the lessons on Earth to Mars gravity?
StephanTLavavej 6y ago
https://www.planetary.org/articles/08190630-curiosity-wheel-damage https://www.planetary.org/articles/08190630-curiosity-wheel-... explains the root cause.
- bmitc 6y ago
  Thanks for that link. I think I have read something similar in the distant past but read through it again. > There are [places] on Earth that do have these sharp ventifacts, but we hadn't seen them on Mars and we didn't test against them This is whats so curious. In their testing on Earth after the fact, they found: > Bedrock with lots of rocks: ~8 kilometers > Lots of rocks, not on bedrock: 13-14 kilometers > Bedrock with few rocks (think flagstones): 30-40 kilometers or more It's just very surprising they didn't think to test on more varied Earth terrains, looking for worst case scenarios, where they would have clearly found this limitation. It is my understanding that the wheel damage became a major limiting factor of Curiosity's mission.