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Why not the moon?

Discussion in 'SpaceX' started by Cosmacelf, Aug 30, 2014.

  1. Cosmacelf

    Cosmacelf Active Member

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    Elon is always talking about Mars being the end goal planet to colonize. But as an avid reader of Heinlein's books, I got to wondering why has Elon has ignored the moon? Presumably the moon would be much easier to get to, and the habitat problem is very similar. You're going to have to generate oxygen on either planet. so, why not the moon?
     
  2. ecarfan

    ecarfan Well-Known Member

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    Compared to Mars the moon has far fewer usable resources and no atmosphere at all.

    Elon is right to focus on Mars.
     
  3. Cosmacelf

    Cosmacelf Active Member

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    The atmosphere on Mars is pretty useless. Your need a pressure suit there, just like on the moon.
     
  4. ItsNotAboutTheMoney

    ItsNotAboutTheMoney Active Member

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    #4 ItsNotAboutTheMoney, Aug 30, 2014
    Last edited: Aug 30, 2014
    The moon has extrmely low gravity. No atmosphere, extreme physi c al difficulty.

    Mars wouldn't be easy, but at least it has basic resources we could work with.
     
  5. ecarfan

    ecarfan Well-Known Member

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    I didn't say it was breathable or that the surface pressure was anything like 1ATA on earth. But it is a resource. The moon has no atmosphere at all.
     
  6. falconeer

    falconeer Member

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    #1 Reason is resources. The moon simply does not have enough of what's needed compared to Mars. A colony on Mars can be self sustaining, very difficult/impossible on moon.

    Mars atmosphere is 95% CO2 which can be used to create methane and oxygen: rocket fuel. ( CO2 + H2O(from soil) + Energy (solar?) -> O2 +CH4).

    Interesting to note that Spacex is developing a methane-oxygen engine called Raptor for exactly this purpose: the ability to refuel on Mars.

    #2 is that the moon is not far enough to provide adequate protection from certain doomsday events: nuclear war, deadly virus, large asteroids... etc
     
  7. Dutchie

    Dutchie Member

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    I think you be quite OK on the moon for nuclear war and deadly virusses and the chance of a large asteroid hitting Mars is greater on Mars than on Earth/Moon as Mars is closer to the asteroid belt.
     
  8. falconeer

    falconeer Member

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    Not really. It's pretty easy to launch a nuke from earth to the moon, and considering that the Apollo astronauts arrived within 3 days, somebody crazy could nuke the moon, and there really won't be time to do anything. Same goes for deadly virus, since travel would be frequent and quick between earth and moon the chance of some deadly virus spreading is much, much higher. As for asteroids, yeah it's true that mars is closer to the asteroid belt, but the point is that earth and moon are close enough that a bunch of nearby asteroids or comets could damage both earth and moon. Basically the idea is don't put all your eggs in one basket, the moon is too close for that.
     
  9. astrotoy

    astrotoy Member

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    The Martian history shows that liquid water once was prevalent on the surface (dried river beds) and there is the not unreasonable possibility that life formed and may even still exist underground. This was a major reason why the US has spent a lot of effort going to Mars on several unmanned missions. Also the day is very similar in length and the extremes of temperature are not unlike the most extreme areas on the earth where life does exist. Mars is smaller, with less gravity than the earth, but there clearly is an atmosphere.

    The moon on the other hand has no real evidence of any life and no real atmosphere. Because it is tidally locked to the earth - same side faces the earth all the time, the sun bakes the surface for a long time (a couple of weeks) and then it gets really cold for 2 weeks.

    I'm not a planetary scientist, so I am not an expert in this, but I am a PhD astronomer, hopefully not the only one in the TMC.
     
  10. Cosmacelf

    Cosmacelf Active Member

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    So you want to create methane from a very thin co2 atmosphere? Frankly, sounds like mining the moon would be easier. Any moon settlements would presumably be underground, so the 28 day long day, and extreme heat/cold wouldn't be an issue.
     
  11. Reykjavik

    Reykjavik Member

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    Holding an earth atmosphere's worth of pressure against complete vacuum is far more difficult than holding it against one tenth of earth's atmosphere's pressure.

    Gravity on Mars is low, but gravity on the moon is lower still.

    Mars has more water.

    Mars has an atmosphere with CO2, which can be used to create rocket fuel when you add energy.

    The atmosphere also makes the temperature less crazy.

    The moon just isn't a place where you can make stuff happen. A legitimate self sustaining Mars colony is possible. On the Moon, it is less realistic.

    To survive, we need breathable air, acceptable pressure, and acceptable temperature. For long term life, we also need acceptable levels of radiation, gravity and general progress. These are all much more difficult on the Moon than on Mars.
     
  12. Cosmacelf

    Cosmacelf Active Member

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    Where did you get that Martian air pressure is 1/10th of earth? It is actually almost 1/200th the sea level air pressure. See Atmosphere of Mars - Wikipedia, the free encyclopedia. There isn't much engineering difference keeping air pressure against a vacuum and against 1/200th sea level air pressure.

    Lower gravity really doesn't matter. Humans live in zero gravity for six months or longer on space stations.
     
  13. Krugerrand

    Krugerrand Active Member

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    Why not the moon? For the same reason, why not a Hybrid Model S: Go big, or go home. :wink:
     
  14. Johan

    Johan Took a TSLA bear test. Came back negative.

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    6 months in 0 gravity makes the body seriously weak. Living for years and years in low gravity as on the moon would be very detrimental.
     
  15. Cosmacelf

    Cosmacelf Active Member

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    It wouldn't be detrimental if you stayed on the moon. We are talking about colonizing these worlds.
     
  16. Johan

    Johan Took a TSLA bear test. Came back negative.

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    #16 Johan, Aug 31, 2014
    Last edited: Aug 31, 2014
    But those people would never tolerate earth-like gravity again. Their muscles and bones would be very weak and how that affects physiology over years or decades is completely unkown.

    BTW gravity on Mars isn't great either. This is a good read by a doctor with good insight:
    The Strange, Deadly Effects Mars Would Have on Your Body | Opinion | WIRED
     
  17. richkae

    richkae VIN587

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    Having no sun for 2 weeks at a time makes also using the most important energy resource - the sun - very difficult. That also makes the moon much more difficult than mars.
     
  18. Doug_G

    Doug_G Lead Moderator

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    One word: water.

    Mars has quite a lot. The moon doesn't.
     
  19. Grendal

    Grendal Active Member

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    Why not a moon base? I would think that a base for staging a Mars colony would be useful. Granted that you'd have to boost in and out of the moon's gravity which uses fuel but the fact that you can create a fuel and supply storage depot there should be helpful for building a long term Mars colony.

    As an alternative, why not an orbital base for similar reasons. The 2001 ring space station would work. Or just some sort of way station for fuel and supplies.

    Basically, I'd like to see real industry happening off planet.
     
  20. ecarfan

    ecarfan Well-Known Member

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    I suggest you read Robert Zubrin's book "The Case for Mars" which explains in detail why a moon base or an earth orbit station for vehicle assembly is unnecessary and costly. There is no need for that approach. His "Mars Direct" plan is far cheaper and more efficient.
     

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