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The moon has no atmosphere, so living on it seems less friendly and far more dangerous. Long term, terra forming is not going to happen, because it won't hold a

The moon has no atmosphere, so living on it seems less friendly and far more dangerous. Long term, terra forming is not going to happen, because it won't hold an atmosphere. That said, as a moon base it has a lot of things going for it, but I'm not sure if there are significant advantages of going there as a stopping point before going elsewhere, when you can achieve many things in orbit with some advantages of not having to take off again.

flukus 8y ago
For all intents and purposes the martian atmosphere is no different to the moons, it's 0.6% of earths atmosphere.
- rdtsc 8y ago
  > For all intents and purposes the martian atmosphere is no different to the moons Not sure I agree with all intents and purposes. Maybe just some of them? Like say if the intent is to extract CO2 or N2 from the atmosphere, then you'd find more on Mars. Those two things are pretty important for growing things and breathing. Another intent and purpose could be to airo-break the space craft as it flies in for a landing. Though it is probably more annoying than it helps, in the sense that Mars has enough atmosphere that you need to deal with it, but not enough to be helpful in the final descent phase.
- mdorazio 8y ago
  Except 0.6% vs. 0% is a huge difference. For example, on Mars you have the option of making rocket fuel from the atmosphere or compressing and scrubbing it slightly for use in greenhouses. Not possible on the moon without basically baking rocks. Mars also gives you the option of aerobraking to shed velocity when landing, which is a big saver on fuel for delta-v requirements. And even though it's nowhere near as good as Earth's atmosphere for blocking harmful radiation, it's still way better than the moon. On the other hand, the moon has a lot going for it for manufacturing. It's at the top of Earth's gravity well and has low gravity itself without being microgravity. That lets you move massive things around easily and shoot them out of launchers to get back to earth without all the problems that come with "zero-g" conditions. It's also a lot closer to the sun than Mars is, so solar panels give you up to 50% more power for the same area. You also don't have to contend with dust storms (though moonquakes could be an issue).
  - posterboy 8y ago
    > On the other hand, the moon has a lot going for it for manufacturing A side hat doesn't face terrestrial cameras for example. taps glasses, pushes tinfoil hat slightly back
- sigstoat 8y ago
  > For all intents and purposes that's excessive. certainly neither one has even the pressure to keep a human alive for any amount of time. mars has got teratons of carbon dioxide, which is useful stuff. little bits of some other handy gases. the moon has got 10 tons of atmosphere, total.
- staticfloat 8y ago
  One difference is gravitational pull; martian gravity is ~2x lunar gravity, which makes the solar wind an even larger danger to any atmosphere you would generate. The distances from the moon's surface at which atmosphere could be stripped away would be proportionally shorter. In either case, the technological breakthroughs we would need in order to actually generate a useful atmosphere are large enough that I would be very excited to just see the byproducts of such breakthroughs.
MikkoFinell 8y ago
You can't really terraform Mars either, not enough gravity. And even if it was possible, the amount of work required to bring the air there is orders of magnitude more than simply building domes over some select craters and filling those with air, a sort of micro terraforming if you will.
- sigstoat 8y ago
  > You can't really terraform Mars either what's wrong with Zubrin's plan? > not enough gravity. what's gravity got to do with it? ADDED: if you're going to tell me the gravity is necessary to hold onto the atmosphere, great, i'm actually familiar with that mechanism. i assert that mars' proclivity for losing the lighter atmosphere over millions of years isn't relevant, and that it'll hold onto everything important for Long Enough.
  - okonomiyaki3000 8y ago
    Without enough gravity, your atmosphere leaks away into space. This may have already happened to mars once.
    - sigstoat 8y ago
      happened once? because the gravity changed? it'd be an ongoing process. and only hydrogen and helium are currently prone to jeans escape on mars. the current dominant mechanism for atmospheric loss is the solar wind. which eats away ~1/3 megaton/century. mars has teratons of atmosphere remaining. and it can be added faster than that rate of loss. (once warmed up, oxygen may begin to escape the atmosphere again. not necessarily faster than it can be replaced, though.)
  - ajross 8y ago
    > what's gravity got to do with it? When the speed of molecules in the atmosphere (thermal, and thus dependent on molecular weight) approaches escape velocity for the body, the atmosphere starts to leak that component. Gasses like N2 (molecular weight 28) and oxygen (32) will "stick" to Earth where Helium (4) won't. Mars can hold CO2 (44) but not O2.

flukus 8y ago

For all intents and purposes the martian atmosphere is no different to the moons, it's 0.6% of earths atmosphere.

rdtsc 8y ago
> For all intents and purposes the martian atmosphere is no different to the moons Not sure I agree with all intents and purposes. Maybe just some of them? Like say if the intent is to extract CO2 or N2 from the atmosphere, then you'd find more on Mars. Those two things are pretty important for growing things and breathing. Another intent and purpose could be to airo-break the space craft as it flies in for a landing. Though it is probably more annoying than it helps, in the sense that Mars has enough atmosphere that you need to deal with it, but not enough to be helpful in the final descent phase.
mdorazio 8y ago
Except 0.6% vs. 0% is a huge difference. For example, on Mars you have the option of making rocket fuel from the atmosphere or compressing and scrubbing it slightly for use in greenhouses. Not possible on the moon without basically baking rocks. Mars also gives you the option of aerobraking to shed velocity when landing, which is a big saver on fuel for delta-v requirements. And even though it's nowhere near as good as Earth's atmosphere for blocking harmful radiation, it's still way better than the moon. On the other hand, the moon has a lot going for it for manufacturing. It's at the top of Earth's gravity well and has low gravity itself without being microgravity. That lets you move massive things around easily and shoot them out of launchers to get back to earth without all the problems that come with "zero-g" conditions. It's also a lot closer to the sun than Mars is, so solar panels give you up to 50% more power for the same area. You also don't have to contend with dust storms (though moonquakes could be an issue).
- posterboy 8y ago
  > On the other hand, the moon has a lot going for it for manufacturing A side hat doesn't face terrestrial cameras for example. taps glasses, pushes tinfoil hat slightly back
sigstoat 8y ago
> For all intents and purposes that's excessive. certainly neither one has even the pressure to keep a human alive for any amount of time. mars has got teratons of carbon dioxide, which is useful stuff. little bits of some other handy gases. the moon has got 10 tons of atmosphere, total.
staticfloat 8y ago
One difference is gravitational pull; martian gravity is ~2x lunar gravity, which makes the solar wind an even larger danger to any atmosphere you would generate. The distances from the moon's surface at which atmosphere could be stripped away would be proportionally shorter. In either case, the technological breakthroughs we would need in order to actually generate a useful atmosphere are large enough that I would be very excited to just see the byproducts of such breakthroughs.

MikkoFinell 8y ago

You can't really terraform Mars either, not enough gravity. And even if it was possible, the amount of work required to bring the air there is orders of magnitude more than simply building domes over some select craters and filling those with air, a sort of micro terraforming if you will.

sigstoat 8y ago
> You can't really terraform Mars either what's wrong with Zubrin's plan? > not enough gravity. what's gravity got to do with it? ADDED: if you're going to tell me the gravity is necessary to hold onto the atmosphere, great, i'm actually familiar with that mechanism. i assert that mars' proclivity for losing the lighter atmosphere over millions of years isn't relevant, and that it'll hold onto everything important for Long Enough.
- okonomiyaki3000 8y ago
  Without enough gravity, your atmosphere leaks away into space. This may have already happened to mars once.
  - sigstoat 8y ago
    happened once? because the gravity changed? it'd be an ongoing process. and only hydrogen and helium are currently prone to jeans escape on mars. the current dominant mechanism for atmospheric loss is the solar wind. which eats away ~1/3 megaton/century. mars has teratons of atmosphere remaining. and it can be added faster than that rate of loss. (once warmed up, oxygen may begin to escape the atmosphere again. not necessarily faster than it can be replaced, though.)
- ajross 8y ago
  > what's gravity got to do with it? When the speed of molecules in the atmosphere (thermal, and thus dependent on molecular weight) approaches escape velocity for the body, the atmosphere starts to leak that component. Gasses like N2 (molecular weight 28) and oxygen (32) will "stick" to Earth where Helium (4) won't. Mars can hold CO2 (44) but not O2.