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[MetalSlimeHunt]

You would have to process 150 tons of Lunar regolith in order to extract one ton of He3. It isn't a very cooperative resource.

Erm... I'm not exactly sure what you mean by cooperative, but that's like 6667 grams per ton. Like, 500 times better than the resource-ore ratio you get with a nice gold mine 1 to 150 is like... salt in the ocean. I know 150 tons processed per ton extracted sounds like a lot, but it really isn't.

None of those things are on the moon, though.

[thobal]

Yeah, but it's still a great resource-to-ore ratio. And the real promise of space is as a nice place to move lots of dirty industry. I say we pollute the hell out of the moon. Build big solar panels all over the sky and beam the energy back here. Mine the universe and end hunger, end want. Can you imagine it, a big crate full of cheap plastic crap all stamped "Made on Titan" parachuting out of the sky? Can you imagine it?

[GreatWyrmGold]

2. Are meteor impacts really so common as to create clouds of dust that linger for any appreciable amount of time? Doesn't a lack of air mean it will fall back to the surface pretty fast?

I'm not totally sure. There's no air, true, but there's also very little gravity. It wouldn't take a very extreme impact to eject the dust into a stable or unstable orbit, the latter of which would cause it to rain back down at a later date.

Well, depending on the speed the meteor hit and how loose the dust is, it might impact later, but anything not reaching orbit would fall about as fast as a rock. No air means no air resistance, and 1/6 of a G isn't exactly negligible gravity...

What would Neil Armstrong do?

Hotwire the Lunar Lander with a pencil and eject right before it crashes and explodes, then write the mission report. All of those things really happened, by the way, though not at the same time.

Let me rephrase that. What did the Apollo mission do to avoid the toxicity of lunar dust?

I can see Mercury, given its closeness to Sol and the resultant increase in the efficiency of solar plants, but aside from trying to "spread out" the human population, why?

No, that's pretty much exactly why. Spread the human population like self-replicating peanut butter. The more places we are, the more likely it is that a major cataclysm will fail to kill us all, leaving survivors to rebuild and/or seek bloody genocidal revenge.

What kind of cataclysm? The only thing I can really see posing a threat to all civilization on Earth but not, say, Mercury, is some sort of social issue which doesn't leave orbit, or perhaps an environmental issue. In the latter case, most of humanity will die, and having half a dozen colonies isn't going to be better than one, better-funded one. Depending on how many people are in each and how easy interplanetary travel is, it could easily be much worse. Anyways, the idea that sending people to other planets could stop overpopulation is faulty. Not only is the benefit minimal, barring massive extraterrestrial agriculture, but we'd just be shoving our Malthusian expiration date a little down the line unless we all adopted some form of birth limits.

And I guess there might be interesting and/or valuable things on Venus. Maybe.

It doesn't even have a magnetic field.

And, not to be condescending (a sure sign that I'm about to fail), but...50 kilometers is some really tall stilts.

Who said anything about stilts? The idea is that they'd be balloons, of a sort. It eliminates all the problems except corrosion.

Well,if you're in a dirigible habitat, the acid rain eating at the envelope is going to be a major problem...

You would have to process 150 tons of Lunar regolith in order to extract one ton of He3. It isn't a very cooperative resource.

Erm... I'm not exactly sure what you mean by cooperative, but that's like 6667 grams per ton. Like, 500 times better than the resource-ore ratio you get with a nice gold mine 1 to 150 is like... salt in the ocean. I know 150 tons processed per ton extracted sounds like a lot, but it really isn't.

None of those things are on the moon, though.

I highly doubt that, but anyways your argument is tantamount to disparaging a gold mine for its lack of tin.

Yeah, but it's still a great resource-to-ore ratio. And the real promise of space is as a nice place to move lots of dirty industry. I say we pollute the hell out of the moon. Build big solar panels all over the sky and beam the energy back here. Mine the universe and end hunger, end want. Can you imagine it, a big crate full of cheap plastic crap all stamped "Made on Titan" parachuting out of the sky? Can you imagine it?

The sky's the limit, so don't try for the impossible. I would lower expectations some. This won't single-handedly save the world. Chinese workers shipping from China will still be cheaper than Lunar workers shipping from Luna. It could help, but we'd need a coordinated effort to actually save Earth and humanity.

[Mr Space Cat]

It could help, but we'd need a coordinated effort to actually save Earth and humanity.

...so mankind is stuck on this rock forever. 

PTW.

[thobal]

As far as the dust thing goes, it isn't poison, it's just fine and abrasive. Basically might cause silicosis. They weren't really exposed to very much of it and didn't really breath in much of it. Symptoms were reportedly like "hay fever" and cleared up in about a day.
http://science.nasa.gov/science-news/science-at-nasa/2005/22apr_dontinhale/

The real problem is that it might get everywhere, clog joints, gears, and mess with equipment.

How does it get up in "the air"? Static electricity.
http://en.wikipedia.org/wiki/Lunar_soil#Moon_dust_fountains_and_electrostatic_levitation

[sneakey pete]

In regards to the earth/mars trip, there's only so much that advanced engines can do, you're never going to get the 3-5 day transfer time that you get with the moon, and aswell as that you have the fact that the optimal transfer only lines up once every 2 years. at other times there's a whole lot further you need to go, due to the planets being out of sync.

[mainiac]

If you've made it out of a gravity well the last thing you want to do is go back down another gravity well.  The moon is a million times more viable a location then mars because it's possible to go into lunar-earth transfer orbit without using rockets.  That's a game changer because it lets you put lunar mass into a zero gravity environment.
From the moon we get the following easily accessible resources:
Abundant iron
Abundant carbon
Abundant silicon
Abundant oxygen
Sufficient water for the first few million colonists

These resources are enough to create artificial habitats in space and make them habitable for humans and crops.  They also allow you to make solar panels en masse.  Solar panels outside the earths atmosphere would be about 6 times as efficient as those on space (constantly at peak power, no interference, no nighttime) and energy could be exported to earth through microwave power transmission.  This means that your colony can have a return on investment beyond a place to send people.  Also your colonists get to enjoy ideal weather conditions year round, get full gravity unlike planet-side and can do their heavy construction and fabrication in a zero gravity environment.  This allows lunar mining to expand, along with stuff like getting water from near earth asteroids.  Do that and you can get into the real business: real estate.

On earth when you make real estate you are limited by the shortage of land in valuable areas.  In space you are limited only by the amount of steel you can produce plus you can build in three directions.  All you need to produce space and farmland for a person is more steel and the moon has enough materials to sustain hundreds of trillions (yes trillions) of colonists once tap other sources for water.  Add in things like low transportation costs and cheap energy and it would make sense to migrate en masse and leave the earth pretty empty.  The costs of emigration wouldn't be that high because it's a one way trip to low orbit, not a round trip and you'd get serious economies of scale once you start doing more then hundreds of launches a year.

[alway]

As far as the dust thing goes, it isn't poison, it's just fine and abrasive. Basically might cause silicosis. They weren't really exposed to very much of it and didn't really breath in much of it. Symptoms were reportedly like "hay fever" and cleared up in about a day.
http://science.nasa.gov/science-news/science-at-nasa/2005/22apr_dontinhale/

The real problem is that it might get everywhere, clog joints, gears, and mess with equipment.

How does it get up in "the air"? Static electricity.
http://en.wikipedia.org/wiki/Lunar_soil#Moon_dust_fountains_and_electrostatic_levitation

Which is why pretty much all colony designs I've seen store the suits on the outside. Well, one of the reasons; they're also cheaper than airlocks. http://en.wikipedia.org/wiki/Suitport

Spoiler (click to show/hide)

Suitports carry two major advantages over traditional airlocks. First, the mass and volume required for a suitport would be significantly less than that required for an airlock. Launch mass is at a premium in modern chemical rocket-powered launch vehicles, at an estimated cost of US$60,000 per kilogram delivered to the lunar surface.[4]
Secondly, suitports can eliminate or minimize the problem of dust mitigation. During the Apollo program, it was discovered that the lunar soil is electrically charged, and adheres readily to any surface with which it comes into contact, a problem magnified by the sharp, barb-like shapes of the dust particles.[5] Lunar dust may be harmful in several ways:
The abrasive nature of the dust particles may rub and wear down surfaces through friction.
The dust may damage coatings used on gaskets, optical lenses, solar panels, windows, and wiring.
The dust may cause damage to an astronaut's lungs as well as nervous and cardiovascular systems, leading to conditions such as pneumoconiosis.[6][7]
During the Apollo missions, the astronauts donned their space suits inside the Apollo Lunar Module cabin, which was then depressurized to allow them to exit the vehicle. Upon the end of EVA, the astronauts would re-enter the cabin in their suits, bringing with them a great deal of dust which had adhered to the suits. Several astronauts reported a "gunpowder" smell and respiratory and/or eye irritation upon opening their helmets and being exposed to the dust.[5]
With a suitport, dust or other environmental contaminants cannot enter the cabin of the vehicle.[1] When the suit is attached to the vehicle, any dust which may have adhered to the backpack of the suit is sealed between the outside of the backpack and the vehicle-side hatch. Any dust on the suit that is not on the backpack remains sealed outside the vehicle. Likewise, the suitport prevents contamination of the external environment by microbes carried by the astronaut.

So yeah; that issue's solved, and is being integrated into the next generation of spacecraft and spacesuits already.

[MetalSlimeHunt]

That settles it then. Lunar dust is gunpowder. We can't settle the moon. If the Soviets were ever to set off that much gunpowder, America would be destroyed. We must nuke the moon while we still can.

[alway]

Reboot Project A119 then.
http://en.wikipedia.org/wiki/Project_A119

Project A119, also known as "A Study of Lunar Research Flights", was a top-secret plan developed in 1958 by the United States Air Force. The aim of the project was to detonate a nuclear bomb on the Moon to boost public morale in the United States after the Soviet Union took an early lead in the Space Race. The existence of the project was revealed in 2000 by a former executive at the National Aeronautics and Space Administration (NASA), Leonard Reiffel, who led the project in 1958. A young Carl Sagan was part of the team responsible for predicting the effects of a nuclear explosion in low gravity.
Project A119 was never carried out, primarily because a moon landing would be a much more acceptable achievement in the eyes of the American public. The project documents remained secret for nearly 45 years, and despite Reiffel's revelations, the United States government has never officially recognized its involvement in the study.

[Sheb]

Mainiac, we got abundant Iron and water on Earth, and it's way easier to get around here. Why can't we build more real estate here?

Anything that can be done on the Moon can be done more easily on Earth, or in LEO. (Except a space shipyard).

[FearfulJesuit]

Gravity, I would assume. Lunar gravity is a sixth that of Earth's; assuming there are no exponential or polynomial relations I'm not aware of, that means it's as easy to build something six hundred meters high on the Moon (all things being equal) as something a hundred meters high on Earth. The cities of the future will make Manhattan and Shanghai look puny; mile-high towers and streets hundreds of feet above the ground.

I do start to wonder about transportation at that height. Would you have two levels of streets, say one at ground level and another a kilometer up, because the size of the buildings would increase density to fantastic proportions?

[mainiac]

Mainiac, we got abundant Iron and water on Earth, and it's way easier to get around here. Why can't we build more real estate here?

Anything that can be done on the Moon can be done more easily on Earth, or in LEO. (Except a space shipyard).

Because unlike on earth it's possible to escape the moon without using rockets, just make a large launcher, akin to an aircraft carrier catapult.

Gravity, I would assume. Lunar gravity is a sixth that of Earth's; assuming there are no exponential or polynomial relations I'm not aware of, that means it's as easy to build something six hundred meters high on the Moon (all things being equal) as something a hundred meters high on Earth.

No, you don't want to build on the moon at all.  You launch the materials off the moon and then build in space.  The surface of the moon has gravity and a day night cycle, neither of which you want.  The gravity is too weak for human habitation, it would cause long term health problems.

If you build entirely in space your architect passively controls every aspect of the environment, including space.  You don't need to settle for 1/6 gravity when you can set the spin rate and size of your station to give you exactly the gravity you want.  Depending on the emissivity of the materials you use on the outside of the station you can pick whatever temperature you want it to be inside year round.  By tweaking the shape of the station you chose how strong the winds inside will be.  Set the day night cycle to whatever you want by scheduling the illumination mirrors to shine sunlight into the environment (ok, that part isn't quite passive). 

You can even set the exact parameters of these matters to different levels at different parts of the station.  For the residential and commercial levels you probably want the gravity near 1 g so you put them on the rotating ring.  Agriculture might not need as much gravity so you make the greenhouse structure rotate more slowly or make it smaller in radius.  Industry you want zero g so you make that not rotate at all.  You give the residential sections a day night cycle but for agriculture, commerce and industry you can just have daylight 24/7.  All of this can be done without any active energy expenditures to maintain the light/gravity/temperature levels you want.

[Sheb]

So you want to use the moon as a space shipyard.

[mainiac]

Well sort of but the ships would have no locomotion and wouldn't actually be built at the moon.  You'd launch iron ore from the moon and then smelt it at a refinery in space.  (Space would be a good place for smelting because you could get very high temperatures on the cheap if you just shine a lot of light on your smelting material and then don't radiate it.)  So the moon is really just a mining site and launching point.