Between the lack of air and the constant bombardment of radiation and micrometeorites, humans will need some serious shelter before we can feel at home on the Moon or Mars. While inflating or 3D printing our houses could be one way to pack light for the long trip, the most efficient method might just be to move into the natural shelter that's already there. Now astronomers have systematically analyzed possible lava tubes on the Moon and Mars, and found they may be just what Red Planet realtors are looking for.
Living underground is the easiest way to escape the harsh conditions of the lunar or Martian surface, and scientists have already found a few candidates. NASA has found hundreds of deep pits in the pock-marked rock of the Moon that could make good hidey-holes from the elements, and there's evidence of sprawling networks of lava tubes below the surface.
Don't they realize this has been proven to be a bad idea?
(Score: 2) by HiThere on Thursday September 28 2017, @08:45PM (3 children)
It is not clear that it's possible to grow up in zero gravity.
OTOH, in a large enough environment its a problem that just isn't there. Spin the habitat.
Now the moon and Mars are only lower gravity, not missing gravity. Spinning would be more difficult, but less likely to be needed. The moon has about 1/6G of gravity, so stress on the bones and joints is present, just reduced. Mars is about 40% of standard Earth gravity, so one might expect that this would be a net benefit rather than a problem. (There might well be a problem is you attempted to return to Earth, however, but that's a separate matter.)
Radiation is a real problem that needs to be addressed. So are micro-meteoroids...though I don't know how severe. It might be soluble by just designing all rooms with seal-able doors and relatively small. But radiation is best addressed by putting a layer of rock between you and the radiation. Preferable rock containing lots of lead, but most rock would work, you'd just need a bit more. I also think is should be possible to build a magnetic shield that was low in energy cost for additional protection, but that would only handle charged particles...and "should be possible" doesn't mean that we currently know how to do it.
Personally, I still think that a planet is not a good place to host a civilization, it's only the place where you need to start. But that *is* assuming that we can solve lots of problems that haven't yet been really solved. However, gravity isn't one of them. It's currently a problem because everything we've put up so far it tiny. Even something as large as a high school gym wouldn't have any problem holding a spinning wheel for people to live on. And since you probably don't need a full G that makes the problem even easier.
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(Score: 3, Informative) by FatPhil on Thursday September 28 2017, @10:34PM (2 children)
An absurd statement, unless your high school gyms are hundreds of meters across.
> And since you probably don't need a full G that makes the problem even easier.
Easier, but still not easy, because the issue with small spinning things is not the G value but (a) the difference between G values across the length of the body, and that increases hyperbolically with the radius; and (b) the coriolis effect noticed when of trying to move "forwards" vs. "backwards", if there's too much disparity, your inner ear cannot know if you're upright or not when moving, human motion v/r must be small compared to station omega, so again that increases hyperbolically at small r.
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(Score: 2) by HiThere on Friday September 29 2017, @06:00AM (1 child)
I wasn't thinking of it being the shape of a high school gym. Take the same volume and convert it into a wheel a couple of meters wide and you get a pretty large wheel. But I may have been a bit over-enthusiastic. Not much, I don't think. Of course, a couple of meters wide is still pretty claustrophobic for me.
To my mind a high school gym is about the floor area of two basket ball courts, plus a bit for space in between them, bleachers, etc. And is about (guess) 10 meters tall. A basket ball court is 28.7 by 15.2 m, so say the floor area is 40 m X 40 m X 10 m (est) is about 16,000 m^3. Say the wheel is 4m wide, that means the area of the cross-section through the axis would be 4,000 m. This give a radius of about 63 m. That ought to be pretty reasonable. And I didn't even include enough space for the bleachers. Of course if you were really doing it you wouldn't be using a disk anyway, but rather a toroid, so the volume would give you even more space, but you'd want the ceilings to be over 2 m high, so you wouldn't gain that much.
N.B.: I wasn't talking about this as suitable for living in long term, but rather a sort of minimal construct that would let you generate gravity while in orbit. But looking at it I think people would probably have more space than they do on the ISS.
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(Score: 0) by Anonymous Coward on Friday September 29 2017, @06:44AM
There's no need to build those huge expensive space stations people use as strawman arguments against "artificial gravity".