10 ms·

"[...] a mere 10 miles" You must be kidding... this is a robot, which survived a hard landing, driven on exotic alien terrain, with async remote control from a

by caio1982 10y ago

"[...] a mere 10 miles" You must be kidding... this is a robot, which survived a hard landing, driven on exotic alien terrain, with async remote control from another planet :-) The fact that they built it and drove it for over 15km is absolutely impressive by my engineering standards.

artursapek 10y ago
I think he's just commenting on the wheels, not the mission as a whole. We obviously are good at making wheels that last longer than 10 miles here on Earth.
radiorental 10y ago
Agreed but I would call the landing anything but hard. The precision and care with which that vehicle was delivered to the surface is just a mind boggling feature of engineering.
- wlesieutre 10y ago
  For anyone who missed this, they lowered the rover to the surface from a levitating rocket-powered skycrane.
  - kristjansson 10y ago
    I don't know if there's another true sentence from which I can derive as much joy as this one.
  - cr0sh 10y ago
    ...which was controlled autonomously to boot! Definitely one of the most bad-assed ways to deliver a rover to the surface of another planet. If you had told me as a kid this would be possible, I would have considered it almost impossible, except maybe as a science fiction concept.
JohnJamesRambo 10y ago
Is the terrain any more dangerous or grueling than a desert terrain on earth though?
- caio1982 10y ago
  They drive it over desert-like terrains now to avoid such problems, but AFAIK the very first hole punched to one of the wheels was due to a small pointy rock. Martians rocks suck.
- okket 10y ago
  From my laymen perspective I'd say the terrain itself is less of a problem, the change in temperatures is much more extreme. This article from 2014 has many insights into prior Curiosity wheel damage: http://www.planetary.org/blogs/emily-lakdawalla/2014/08190630-curiosity-wheel-damage.html http://www.planetary.org/blogs/emily-lakdawalla/2014/0819063...
  - mturmon 10y ago
    This is a great article. Thanks for the link. One thing it points out is that the rocks in that particular part of Mars are special: they are sharp and cemented into the terrain. There are places on Earth that have this kind of rock, but they are unusual. The wheels do fine in a rocks-in-sand scenario. The article goes into a lot of detail, and it turns out that some of the obvious armchair science explanations for what is happening are not the case. For instance, the main constraint on the mass of the wheels was not keeping the liftoff mass of the payload under some limit.
  - deleted 10y ago
    [deleted]
- Bartweiss 10y ago
  Sharper rocks than a lot of Earth deserts - less wind and no water to smooth things down. More broadly, though, there are some deserts on Earth that are pretty hair-raising. The NPS guidelines for driving deep in the Canyonlands (on roads, no less) warns that with a high-clearance 4WD pickup, you should still expect "considerable risk of vehicle damage". Curiosity is going a lot slower, but it doesn't have the luxury of roads or anyone to toss on a spare tire.
deleted 10y ago
[deleted]
JabavuAdams 10y ago
This is not obvious from the perspective of someone who's not familiar with rocketry or how light space structures need to be.
gambiting 10y ago
I'm curious(and this is in no way meant to belittle the work they've done) - if you drove a normal Earth car on the surface of Mars, how would the wheels and tyres behave in Martian conditions? Obviously we have off-road tyres here on Earth which can withstand some extreme abuse, so I'm just wondering - is Martian soil just full of sharp objects? Or is something else going on here?
- passivepinetree 10y ago
  Well, regardless of how well an Earth car would perform, it'd likely be far too heavy/expensive to get to Mars in the first place. It's impressive how NASA can solve problems with the resource constraints they have.
  - jonknee 10y ago
    It would obviously be a dumb idea, but Curiosity is in the same ballpark as a car in both size and weight (1,982 lbs). A Smart Car is ~1,800 pounds, so it's actually heavier than some Earth cars!
    - passivepinetree 10y ago
      Interesting, I didn't know that Curiosity was that heavy! It's a ways away from Jeep Wrangler/military Humvee territory (especially if you loaded one of those up with the required scientific instruments) but it'd be cool to see NASA go with something heavier-duty for longer-range missions in the future.
- jonknee 10y ago
  I think low temperatures alone would wreck Earth tires (and the rest of the car, but that's a different story).
- brians 10y ago
  It does have sharp objects, but ordinary truck balloon tires would handle those relatively well. But at night, the temperatures drop to -100 °C, and your rubber tires freeze and shatter. Also, rubber's much heavier, and they just couldn't bring that weight. They really couldn't drop that weight from the sky crane, not without increasing the shock absorbers in the legs... which would have meant more weight, and the plan's just impossible. It also has horrifically abrasive dust, much worse than anyplace on earth. The abrasion from that would wreck a balloon tire seal---hard to predict how quickly. A balloon tire also goes from "fine" to "useless" with one puncture. Apparently they got surprised by the sharp rocks: http://www.planetary.org/blogs/emily-lakdawalla/2014/08190630-curiosity-wheel-damage.html http://www.planetary.org/blogs/emily-lakdawalla/2014/0819063... , not having seen anything like that from previous missions.

artursapek 10y ago

I think he's just commenting on the wheels, not the mission as a whole. We obviously are good at making wheels that last longer than 10 miles here on Earth.

radiorental 10y ago

Agreed but I would call the landing anything but hard. The precision and care with which that vehicle was delivered to the surface is just a mind boggling feature of engineering.

wlesieutre 10y ago
For anyone who missed this, they lowered the rover to the surface from a levitating rocket-powered skycrane.
- kristjansson 10y ago
  I don't know if there's another true sentence from which I can derive as much joy as this one.
- cr0sh 10y ago
  ...which was controlled autonomously to boot! Definitely one of the most bad-assed ways to deliver a rover to the surface of another planet. If you had told me as a kid this would be possible, I would have considered it almost impossible, except maybe as a science fiction concept.

JohnJamesRambo 10y ago

Is the terrain any more dangerous or grueling than a desert terrain on earth though?

caio1982 10y ago
They drive it over desert-like terrains now to avoid such problems, but AFAIK the very first hole punched to one of the wheels was due to a small pointy rock. Martians rocks suck.
okket 10y ago
From my laymen perspective I'd say the terrain itself is less of a problem, the change in temperatures is much more extreme. This article from 2014 has many insights into prior Curiosity wheel damage: http://www.planetary.org/blogs/emily-lakdawalla/2014/08190630-curiosity-wheel-damage.html http://www.planetary.org/blogs/emily-lakdawalla/2014/0819063...
- mturmon 10y ago
  This is a great article. Thanks for the link. One thing it points out is that the rocks in that particular part of Mars are special: they are sharp and cemented into the terrain. There are places on Earth that have this kind of rock, but they are unusual. The wheels do fine in a rocks-in-sand scenario. The article goes into a lot of detail, and it turns out that some of the obvious armchair science explanations for what is happening are not the case. For instance, the main constraint on the mass of the wheels was not keeping the liftoff mass of the payload under some limit.
- deleted 10y ago
  [deleted]
Bartweiss 10y ago
Sharper rocks than a lot of Earth deserts - less wind and no water to smooth things down. More broadly, though, there are some deserts on Earth that are pretty hair-raising. The NPS guidelines for driving deep in the Canyonlands (on roads, no less) warns that with a high-clearance 4WD pickup, you should still expect "considerable risk of vehicle damage". Curiosity is going a lot slower, but it doesn't have the luxury of roads or anyone to toss on a spare tire.

deleted 10y ago

[deleted]

JabavuAdams 10y ago

This is not obvious from the perspective of someone who's not familiar with rocketry or how light space structures need to be.

gambiting 10y ago

I'm curious(and this is in no way meant to belittle the work they've done) - if you drove a normal Earth car on the surface of Mars, how would the wheels and tyres behave in Martian conditions? Obviously we have off-road tyres here on Earth which can withstand some extreme abuse, so I'm just wondering - is Martian soil just full of sharp objects? Or is something else going on here?

passivepinetree 10y ago
Well, regardless of how well an Earth car would perform, it'd likely be far too heavy/expensive to get to Mars in the first place. It's impressive how NASA can solve problems with the resource constraints they have.
- jonknee 10y ago
  It would obviously be a dumb idea, but Curiosity is in the same ballpark as a car in both size and weight (1,982 lbs). A Smart Car is ~1,800 pounds, so it's actually heavier than some Earth cars!
  - passivepinetree 10y ago
    Interesting, I didn't know that Curiosity was that heavy! It's a ways away from Jeep Wrangler/military Humvee territory (especially if you loaded one of those up with the required scientific instruments) but it'd be cool to see NASA go with something heavier-duty for longer-range missions in the future.
jonknee 10y ago
I think low temperatures alone would wreck Earth tires (and the rest of the car, but that's a different story).
brians 10y ago
It does have sharp objects, but ordinary truck balloon tires would handle those relatively well. But at night, the temperatures drop to -100 °C, and your rubber tires freeze and shatter. Also, rubber's much heavier, and they just couldn't bring that weight. They really couldn't drop that weight from the sky crane, not without increasing the shock absorbers in the legs... which would have meant more weight, and the plan's just impossible. It also has horrifically abrasive dust, much worse than anyplace on earth. The abrasion from that would wreck a balloon tire seal---hard to predict how quickly. A balloon tire also goes from "fine" to "useless" with one puncture. Apparently they got surprised by the sharp rocks: http://www.planetary.org/blogs/emily-lakdawalla/2014/08190630-curiosity-wheel-damage.html http://www.planetary.org/blogs/emily-lakdawalla/2014/0819063... , not having seen anything like that from previous missions.