back to article Chainmail tires re-invent the wheel to get future NASA rovers rolling

NASA has developed chainmail tires with a memory and thinks they'll do the trick for future rovers. As readers of The Register's coverage of the Curiosity Rover may recall, the vehicle has experienced considerable wheel damage that has led to changes to its route in 2014 and a 2017 software update to preserve the wheels and …

  1. Korev Silver badge
    Joke

    Ahhh chainmail, mon amour

  2. Anonymous South African Coward Bronze badge

    Perfect, just what I need... rubber tyres are overrated anyway.

    1. Dave 126 Silver badge

      Your braking distance will be drastically increased, but at least you'll give off some cool-looking bright white sparks as skid down the highways!

      1. allthecoolshortnamesweretaken

        But you can't make 'doughnuts' and stink up the mall parking lot doing it!

        1. Chemical Bob

          "But you can't make 'doughnuts' and stink up the mall parking lot doing it!"

          If the tires are strong enough they could chew up the pavement, tho...

    2. nematoad
      Unhappy

      "...rubber tyres are overrated anyway."

      So is the spelling by the look of things.

    3. Michael Thibault

      "rubber tyres are overrated anyway"

      Especially in low-pressure atmospheres.

  3. 's water music

    chain mail

    send this on to ten more rovers within two weeks to avoid the gypsy curse

    1. Korev Silver badge
      Coat

      Re: chain mail

      I'm too tyred for that...

  4. imanidiot Silver badge

    NASA used similar tech (without the titanium) on the lunar rovers. The spring mesh wheel idea isn't the novelty here.

    1. Hans Neeson-Bumpsadese Silver badge

      Actually, quite scary to think just how old that lunar rover tech is now.

      Have these types of wheels ever been implemented on any terrestrial form of transport? I would have though that they could be better than standard tyres for things like dune buggies.

      1. Anonymous Coward
        Anonymous Coward

        "Have these types of wheels ever been implemented on any terrestrial form of transport?"

        Hmm... I don't think you'd want to use them anywhere wet and muddy, and not on deep sand either; too much of what you're supposed to be driving on would end up inside the tyre instead of beneath it.

        There's also the greater force of gravity on Earth, which would need a heavier build of tyre, with a more robust mesh, or 'weave' as it were, to prevent it from squashing under the greater 'weight'.

        The trouble with a more robust mesh though, is that if you deform it to the same degree as a finer mesh it will be stressed to a greater degree and more likely to become fatigued and break; when you bend something you get different stresses on the inside and outside of the bend, and the thicker the thing you're bending, the greater the differences in stress.

        It might be that the particular combination of dryness (but not deep sand) and lower gravity that you have on the Moon & Mars means that you can use a finer mesh that will still support the vehicle whilst also being more flexible and less susceptible to fatigue.

      2. cray74

        Have these types of wheels ever been implemented on any terrestrial form of transport?

        No, because they have very short lives. The original Apollo rover tires had, as I recall, a life of some tens of miles. It was an award-worthy breakthrough in 2009 to develop similar tires with a range of several thousand kilometers. Which is still rather short compared to the life of a modern car tire (on paved roads.)

        These metal tires are handy in space because they work over a wider temperature range than rubber. While there are polymers with very wide usable temperature ranges (I work with silicones and fluorosilicones used from -60C to +250C), their mechanical properties shift significantly. Rubber at -60C has quite different behavior than the same at 150C, even if you formulate them to avoid a ductile-to-brittle transition at the low end. Metal wires don't experience that change. (Before anyone says it, vacuum is not an issue for rubber tires. It's just a difference of another 14.7psi. The shuttle tires were kept in unpressurized bays while in orbit. Compared to their ~300psi operating presure, vacuum was a rounding error.)

        On the other hand, metal tires experience wear and damage that would just bounce off (har har) a rubber tire. If you CAN use rubber tires because you're in a narrower temperature band (like on Earth), they're a superior option for durability and - usually - traction and ride compared to metal tires. There's just not many reasons to use metal tires on Earth.

    2. Gene Cash Silver badge

      > The spring mesh wheel idea isn't the novelty here.

      No, and even the article mentions that. Using the Ni-Ti metal is the novelty.

    3. Stevie

      NASA used similar tech (without the titanium) on the lunar rovers.

      If we took the Titanium out it wouldn't be crunchy, would it?

    4. cray74

      NASA used similar tech (without the titanium) on the lunar rovers.

      Nitpick: the Apollo lunar rovers did use titanium. The steel wire mesh had about 50% coverage with titanium slats for traction.

      1. imanidiot Silver badge
        Coat

        @cray74:

        You are correct, I had completely forgotten about the slats... --> I'll go hang my head in shame somewhere.

  5. Voland's right hand Silver badge

    So how do you heat it?

    The "shape recovery" magic property of of titanium alloys needs heat. The alloy has two temperatures:

    1. Recovery range - if you warm it up to that temperature it recovers its "remembered" shape

    2. Memorize range - that is the temperature you beat it into shape at.

    Most alloys recover ~ 100 degres or thereabouts. So how do you heat the tyre to that temperature on Mars? Bonus points for doing it evenly so it does not warm up too much and too fast ending up remembering its current shape.

    1. Anonymous Coward
      Anonymous Coward

      Re: So how do you heat it?

      I was thinking the same thing. My guess would be passing a current through the wire and using resistive heating. Whether that's practical for use on a mars rover is another matter.

    2. Graham Dawson Silver badge

      Re: So how do you heat it?

      Or they could alloy the an appropriate ratio of nickel and titanium to ensure its attains superelasticity at the desired temperature range - something they have obviously done, as evidenced by the behavior of the wheel in the video.

      1. Dave 126 Silver badge

        Re: So how do you heat it?

        Indeed, regardless of its heat-activated memory properties, Nickel Titanium can be bent far further than steel and still return to its original shape. Anyone who has played with a pair of titanium spectacle frames knows this.

      2. allthecoolshortnamesweretaken

        Re: So how do you heat it?

        "Or they could alloy the an appropriate ratio of nickel and titanium to ensure its attains superelasticity at the desired temperature range " (And what Dave126 posted.)

        Thinking along similar lines here... Basically, it comes down to using an alloy that maintains elastic properties while in use. As in "that'll just pop back after the force doing the deforming is gone again"; IOW "that'll buff out by itself". Like, you know, a spring. Clever, but if that's what they're doing, the bit about plastic properties is a bit misleading. Time to test the elastic/plastic properties of (sub)editors?

    3. PNGuinn
      Trollface

      Re: So how do you heat it?

      Software update, natch. Teach it to do lots of wheelies.

      OTOH. What alien life will make of all those patterns in the Arizona desert is anyone's guess.

      Guess they’re strapped for cash if they can't get a tyre change truck out that far ....

    4. cray74

      Re: So how do you heat it?

      The "shape recovery" magic property of of titanium alloys needs heat. The alloy has two temperatures:

      True, the *shape memory* effect of the Nitinol family happens with heating. However, the alloys have another useful property: a huge elastic range, called superelasticity or pseudoelasticity. Most normal metals can stretch 0.2% of its original length and snap back to their original shape ("elastic deformation"), and any greater stretching results in permanent shape change ("plastic deformation"). Nitinol and friends can exhibit elastic deformations of up to 6%, or 30x that of other metals. This has nothing to do with the shape memory effect.

      Hence Nitinol is used in eyeglass frames, bra underwires, and (now) space tires.

  6. TrumpSlurp the Troll
    Thumb Up

    Snow chains

    Without needing the rubber underneath.

    Just in time for La Nina.

  7. Anonymous Coward
    Anonymous Coward

    Would there be a critical composition of loose material that would enter into the tyre and then not be shed later? Would that eventually make a solid tyre?

    1. Dave 126 Silver badge

      I guess we have a pretty good idea of the composition of Mars dirt by now... Plus there's naff all water to make the soil claggy and sticky. We can knock up some fake Marsian soil on here and do extensive testing. I suspect that the flexible wheels would soon shed off any bits of grit that might stick in the holes.

      Lunar dust, due to the lack of atmosphere allowing micro meteorite impacts abrading and fusing, is an absolute pain the arse though. It's like tiny fractals of razor sharp glass.

      1. Anonymous Coward
        Anonymous Coward

        "I suspect that the flexible wheels would soon shed off any bits of grit that might stick in the holes."

        My thoughts were that a mesh hole will expand as it distorts*** Then a piece of rock of appropriate size/shape could be forced inside - and be unlikely to escape.

        Just shape alone could be critical if the rock's length is greater than its width.

        Barring Sod's Law such rocks could be uncommon - but over the years they could build up like monks' sandals wearing away steps in old monasteries.

        *** The old party trick of dropping a coin through a smaller hole in a flexible surface

  8. Ochib

    Need get an account with The Astro-Afro-Antarctico-Amer-Asian Auto Association, or Septuple-A

  9. 0laf
    Boffin

    Cold soo cold

    I did wonder how this was going to work at -60C

    But 'tis Nasa, one does feel justified in assuming that they will have given this some thought.

  10. herman

    Spring Steel

    "Shape memory" - We used to call it Spring Steel. Kids, these days...

    Now, get off my lawn!

  11. James 51
    Coat

    Didn't Mark Whatney say something about how a big box of radioactive death could solve all your problems on Mars?

  12. Gotno iShit Wantno iShit

    I couldn't work out what the hell this article was about from the headline. I guess the upside downs spell the word incorrectly just like the Leftpondians do.

    1. allthecoolshortnamesweretaken
      Coat

      Maybe Simon was really tired when he wrote this?

      (Mine's the one with the ADAC membership card in the pocket.)

      1. This post has been deleted by its author

    2. Anonymous Coward
      Anonymous Coward

      Pretty sure 'tyre' is the usual form in Oz & NZ.

  13. Velv
    Coat

    "Throw in the fact that it's not yet possible to send a spare wheel to Mars and have it fitted"

    You can. You just call out The AA or the RAC. But I believe you need to be with your vehicle with your membership card to hand when they arrive. (adapted from Sheldon Cooper, The Big Bank Theory)

    1. Aladdin Sane

      Can you send a spare wheel to Mars?

      No, but I know a man who can...

    2. Steve the Cynic

      "You just call out The AA or the RAC. But I believe you need to be with your vehicle with your membership card to hand when they arrive"

      Not necessarily. I called out the AA on a "Will Join" basis on one occasion. (Specifically, a failed alternator(1).) They arrive, and you end up paying a bit extra compared to a normal join followed by a normal call-out.

      (1) On another occasion, I had the voltage regulator fail "hot"(2) - that's not good, but the car will still run. But the "will join" was for the alternator failing "off". Eventually the car stops because there's no electricity for the ignition, neither from the alternator nor from the now-flat battery.

      (2) That is, not forcing the voltage down to the appropriate range.

  14. anthonyhegedus Silver badge

    *tyre

    please

    1. Anonymous Coward
      Anonymous Coward

      As it is about something in the USA then one should expect their variant spellings - even if only due to cut&paste from original sources.

      There are so many - and really no different from the change in the English spelling of "coud" to "could" in the 15th century so that it matched "would" and "should".

      1. Hollerithevo

        and yet more

        debt for det -- the b put in because monkish types thought the word must have derived from debit

    2. Daniel von Asmuth

      NASA reinvented the tyre

      but the wheel will never tire.

  15. Anonymous Coward
    Anonymous Coward

    hello nasa

    I was that uncurious that I forgot the curiosity rover existed.

    Maybe if they had plonked it down next to the mountains in total recall or that matt damon film I might have been interested in looking at the pictures.

    Im glad the nasa boffins invented something. Probably in the hrs of extreme boredom monitoring this mission.

  16. Alistair
    Windows

    I can just imagine that

    Getting that bugger balanced properly for highway operation will be seriously annoying

  17. Nimby
    Angel

    My old glasses

    The frames of my old glasses were a titanium alloy, super light, super bendy. 3D print a frame, powder coat, cinter up a wheel of titanium (alloy) foam, and there you go. Replaces bones. Replaces tyres. (On Mars rovers.) An expensive modern solution. (Kind of obvious if you ask me, and probably better all around than a memory-metal chain-mail tyre.)

    Or do what an old Mennonite friend did, weld a bunch of rebar to reinforce and add traction to old tractor rims, sans-tyre. It may or may not climb a rocky hill, but it'll last forever. If it rides too bumpy, soften the suspension or drive slowly. Should be fine for a Mars rover. (Except maybe for the whole weight thing.)

  18. PatientOne
    Joke

    Hmmm... 'Chain Mail'... a bit like the 'River Avon'... *twitch*

    Next: Rover foiled by Bodkin like shards...

  19. JimmyPage Silver badge
    Unhappy

    Terrestrial uses ?

    A shame it takes a mission to another planet to kickstart innovation which would enhance the lives of tens of thousands of earthly wheelchair users ?

    In fact if NASA had bothered to scour the less able community, they would have probably found a solution all ready to roll (pun intended).

    I wait the Russian trollbot downvotes.

    1. The Indomitable Gall

      Re: Terrestrial uses ?

      The design spec is very different.

    2. Anonymous Coward
      Anonymous Coward

      Re: Terrestrial uses ?

      Solely to make you happy, have a down-vote.

    3. Spudley

      Re: Terrestrial uses ?

      A shame it takes a mission to another planet to kickstart innovation which would enhance the lives of tens of thousands of earthly wheelchair users ?

      Without commenting on the merits or otherwise of your specific suggestion re this tech, you're missing a major point of trickle-down invention.

      In fact, kickstarting innovation is probably one of the major benefits to humanity of the space industry. There are a significant number of inventions that were first developed in the space industry which have gone on to become mainstream products.

      Far from being a shame that it happened this way, you should be applauding the fact that the space industry is innovating, because some of those innovations will eventually make their way into your hands.

  20. WibbleMe

    I bet they still wont stand up to UK roads

  21. Anonymous Coward
    Anonymous Coward

    Just make a...

    Slinky out of this stuff! The number of times the spring/coil got twisted or bent. :(

  22. W4YBO

    Driving through mining country...

    in southwest Virginia, you'll see dump trucks with rubber tires covered with a heavy, chain-like mesh. The tires on some of these these trucks are 10 - 12 feet diameter, and cost $20,000 plus.

    Several mining companies in the area have only female dump truck drivers because they are so much easier on the equipment.

  23. Stevie

    Bah!

    Nitinol?

    We've known about that for years.

  24. Anonymous Coward
    Anonymous Coward

    Chained to the wheel

    https://www.youtube.com/watch?v=wNSPl1wfwUA

  25. hairydog

    Tires is a perfectly good English word. It means "becomes tired"which is more or less what is happening to the Curiosity rover wheels.

    The round squashy things round wheels are tyres

  26. Augie
    Alert

    Why does everyone always mention Curiosity rover, what about Opportunity????

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