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Driving Model S in the Vacuum

Discussion in 'Model S' started by VolkerP, Nov 7, 2011.

  1. VolkerP

    VolkerP EU Model S P-37

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    Hi all,

    just another thread to kill the time until Model S is launched...

    Wouldn't Model S be the perfect vehicle to drive on the moon? The astronauts still wear their space suits, but apart of that...
    With its light weight architecture and 300 miles of terrestrial range, it surely is capable to carry two astronauts some 200 miles from the landing site, gather some 500 lbs of probes and return.

    What must be modified to make the car work on the vacuum moon surface? pressure sealed HVAC circuits? Enhancements to prevent ingress of moon dust? Other tires?
     
  2. NigelM

    NigelM Recovering Member

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    #2 NigelM, Nov 7, 2011
    Last edited: Nov 7, 2011
    Ummmm, been there, done that.....

    I guess changing the battery technology could add more range:

    Just a problem with the undeveloped charging infrastructure.....
     
  3. gg_got_a_tesla

    gg_got_a_tesla Model S: VIN P65513, Model 3 Res Holder

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    Yeah, heard the grid's a bit dodgy too...

    Gosh, next July (with Model S deliveries) cannot come around soon enough :smile:
     
  4. Tech26

    Tech26 Member

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    Just put new batteries in the moon rover that's already up there.
     
  5. Mycroft

    Mycroft Life happens

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    Solar collecting would be a challenge. Two weeks of continuous sunshine, great! But then followed by two weeks of darkness. :-o
     
  6. VolkerP

    VolkerP EU Model S P-37

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    Of course... So let's jump to Mars. Now we face a faint atmosphere (mostly CO2), low temperatures, and a 0-phase charging infrastructure. With Elon's plans to settle on Mars, he surely want's to take his Model S with him. So what to tell the shop workers to adjust? Washer fluid should go down to -85C, beef up the seat heating, ...?
     
  7. EV_de

    EV_de Model SP10/XP9 EU ZOE#47

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    #7 EV_de, Nov 7, 2011
    Last edited: Nov 7, 2011
    .. and a Fuelcell with Solarpanels for recharge ...
     
  8. JRod0802

    JRod0802 Member

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    #8 JRod0802, Nov 7, 2011
    Last edited: Nov 7, 2011
    I'm no expert, but here are some thoughts I had just because I think this is a fun thought experiment.

    First off, the Model S wouldn't be the ideal lunar vehicle for a number of reasons:

    1) Hard (probably impossible) to get in / out due to space suits

    2) Unnecessarily aerodynamic (adds weight)

    3) Unnecessarily has a roof, mirrors, windshield, air conditioner, heater, 3G connectivity, sound system, etc. All of those add weight and have no use.

    4) A lot of other reasons that I can't think of now...

    ---

    But, for the sake of the thought experiment, the Model S would need the following:

    1) Lower tire inflation (they'd probably explode if exposed to a vacuum normally)

    2) Off-roading tires

    3) Raised up suspension (as much as possible, like maybe 2 feet)

    4) No windshield wiper fluid at all (since it would vaporize before it hit the windshield anyway).

    5) I'm not really sure how liquid cooling works (does it use some kind of AC to cool the liquid?). Anyway, it seems like the whole system would require air at some point. Without air, the battery, motor and coolant would continuously heat up until they broke. The car would only cool down through infrared radiation and through contact with the lunar surface (at night). So large heat sinks (to increase the rate of infrared radiation) would be a good modification.

    6) The lunar surface is 107 degrees Celsius during the day on average (which lasts for two weeks), so the tires would have to not melt (I have no idea what the melting temp of a tire is in a vacuum).

    7) The lunar surface is -153 degrees Celsius during the night on average (which lasts for two weeks), so the tires would have to not freeze and subsequently shatter (I have no idea what that temp would be either).

    8) Various things in the car might not be modifiable to operate in a vacuum, like the LCD screen. A vacuum might just cause it to break. If not, the heat generated at the front of the LCD (which normally cools off due to the movement of air in front of it) might cause it to overheat and break.

    9) Additional pressure sealing would probably be needed in a bunch of other places too. Possibly in the hydraulic braking, possibly in the power steering, etc.

    I can't think of anything else, but if I do, I'll add to this list. Either way, it seems like as long as some necessary modifications were made to keep things pressurized, the biggest issue would be temperature. Some parts of the car would get very hot (through use, sun light and lunar surface temp) and some parts of the car would get very cold (over time in the shade and through lunar surface temp). The car would have to withstand all of this. I feel like if it did work at first, it would only work for a few miles and then stop working for temperature reasons.

    Does anyone else have any ideas?

    Edit: Perhaps you could solve most of these problems by putting the car in a giant pressurized insulated re-enforced transparent hamster ball (I'm guessing that TEG got a picture of one of these the last time he was on the moon, right TEG?). Then it would have air, and you wouldn't need a space suit and you could drive around all day. You just wouldn't be able to leave the hamster ball.

    And it would probably end up getting really hot in there due to the heat of the battery which would heat up the whole place. You could close the doors and windows and run the AC, but that would end up generating a net amount of heat, so it would get much hotter outside the vehicle (but inside the ball). Maybe if you only drive at night the infrared radiation combined with contact with the lunar surface would cancel out the heat generated by the car, and you could drive for a while?
     
  9. mnx

    mnx 2013 P85

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    This makes me wonder why Elon didn't decide to call signature red, "Mars red". :)

     
  10. NigelM

    NigelM Recovering Member

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    #10 NigelM, Nov 7, 2011
    Last edited: Nov 7, 2011
    If I recall correctly the glass transition temperature for rubber is at -60C and melting point for tires around 120C. Nasa already excluded rubber tires for the lunar buggy:

     
  11. VolkerP

    VolkerP EU Model S P-37

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    no more flat tires. I see :rolleyes:

    What bearings are there in Model S drive train and what lubricants do they use?
     
  12. Doug_G

    Doug_G Lead Moderator

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    One comment: cooling.
     
  13. daniel

    daniel Active Member

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    People need air, too, and a narrow temperature range. They can go out into a vacuum wearing space suits, but they cannot live in them. Thus, a human colony on either the moon or Mars would have to be in sealed underground caverns, since in the absence of a protective atmosphere, no dome would be safe from meteors.

    The Model S could be used to drive around inside the cavern, and would be ideal since it would not add pollution to the limited volume of air. Of course the Leaf and other EVs, including golf carts, would be ideal also. JRodo's list of issues makes it clear that no conventional car could be used on the surface of either Mars or the moon. That will requie a purpose-designed vehicle like the moon buggy.
     
  14. Doug_G

    Doug_G Lead Moderator

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    Meteoroids would be pretty easy to protect against. The real issue is radiation. That's why you'd build underground, or at least cover the habitat with "soil" (regolith).
     
  15. daniel

    daniel Active Member

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    How do you protect a dome against chunks of rock coming in at several thousands of miles per hour?
     
  16. Doug_G

    Doug_G Lead Moderator

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    That is a huge misconception. Large meteors are extremely rare; the vast majority are microscopic. Otherwise the International Space Station would already be full of holes, and it's built like a tin can.

    Any structure built on the ground - moon or otherwise - would be made of something rather more robust. Micrometeors aren't going to puncture it. Large stones are so rare they're never going to hit it.

    No, radiation is the issue. You'll want gobs of regolith between you and the sun.
     
  17. VolkerP

    VolkerP EU Model S P-37

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    #17 VolkerP, Jun 8, 2012
    Last edited: Jun 8, 2012
    You protect from particle impact with a double layered shield. The first layer gets punctured, but the particle evaporates. The emanating jet of plasma/vapor is deflected by the second layer. Basically you use the super high kinetic energy of the particle to destroy it on first impact.

    You lose if
    - a sufficiently large object penetrates both layers, or
    - your first layer has gathered enough microscopic holes that a particle does its initial impact on the second layer.

    The ESA probe "Giotto" had a double layered shield system to protect from comet particles which would hit the probe at 68km/s. It's at the bottom of the following picture, denoted "FRONT SHEET/REAR SHEET". Both form the "BUMPER SHIELD" system. You see, Denglish is in use over here in Europse since decades :biggrin:
    giotto1%20slide6_screen.jpg

    Edit: Yes, the shield worked, making Giotto survive an encounter with comet Halley in 1986. The probe took some damage but kept working and could be reused for another comet approaching mission.
     
  18. daniel

    daniel Active Member

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    So we're agreed that the colony will have to live underground.

    There have always been pioneers, but they always knew that if things worked out, they'd live in the fresh air and the light of day. I wonder if anyone would volunteer to live out the rest of their life in what was essentially a prison. You could populate the place with prisoners, of course. But you'd either have a very uncooperative work force, or you establish a slave colony where the descendants of prisoners would be slaves as well. Or you make believe a technology and an economy where high-volume back-and-forth passenger travel is ongoing.

    Who reading this would volunteer to leave Earth and go to Mars to live out the rest of your life underground? Visit the planet and return, volunteers would be plentiful, as long as there was a possibility of survival and return. But leave forever, I doubt it.
     
  19. Doug_G

    Doug_G Lead Moderator

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    You wouldn't be trapped underground; you could go outside in a pressure suit or into a surface glass observation level if you wanted. You just wouldn't want to be exposed all the time, and at times you would have to stay underground for a while due to a solar flare, etc.
     
  20. JRod0802

    JRod0802 Member

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    Or a months-long planet engulfing dust storm, in the case of Mars.
     

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