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Mine The Moon For Helium-3
Rob Kennedy writes "A story at The Daily Cardinal is reporting that UW-Madison researchers are looking to mine the moon for helium-3 as an energy source, which supposedly would yield about 1000 times more energy per pound than coal. Although there are several hurdles that would need to be cleared, The Associated Press mentions one catch in particular: 'The researchers still are working on building a helium-3 reactor that would produce more energy than it takes in.' Indeed. SciScoop has a more in-depth discussion of the prospect."
Put out more energy than it takes in? Once again, never trust the AP for science.
great now whats going to keep it floating up there??? :)
I mean come on. We can't even get one watt of positive energy flow out of Fusion and they already want to mine the moon for it. Let's spend our time developing better fission reactors, including ones for space engines. Then we can use them to get our scientists to the moon so they can play with Helium-3 and Fusion all they want.
Javascript + Nintendo DSi = DSiCade
Wow. Here's a space.com article from three and a half years ago on the same subject.
If your bitterest enemies are people who hack the heads off civilians, then I would say you're doing something right.
Well, we're still working on getting a net-gain fusion reaction going with deuterium and tritium, which is a considerably easier fusion reaction to start than deuterium and Helium-3. The advantage with the D-He3 reaction is that it is theoretically aneutronic, but in any D-He3 fusion-capable environment you're going to have enough D-D fusion to have to worry about neutrons anyway...
...just like it was 50 years ago.
Is there REALLY anything wrong with Fission power?
Yes. It's politically and socially unacceptable.
"They redundantly repeated themselves over and over again incessantly without end ad infinitum" -- ibid.
- Homer J. Simpson
There is no gravity...the earth just sucks.
Let's put is this way... have you heard the BeeGees?
"Freedom means freedom for everybody" -- Dick Cheney
There isn't much helium-3 involved -- no more than a few thousand tons. People move that much mass around every day, and you don't see catastrophic tides occurring every time a freighter goes by, do you?
People generally don't have a good idea of just how damn heavy planets are. To make a measurable difference in the Moon's behavior, it would be necessary to move over 1,000,000,000,000,000 tons of material -- over a million tons for every man, woman, and child on Earth!
"They redundantly repeated themselves over and over again incessantly without end ad infinitum" -- ibid.
Mining the moon would require placing the equivalent of heavy "earth" moving equipment on the surface. Doing that is expensive. So is getting the results back off the surface. He3 is only in the first few feet of moon surface because it comes from the sun. Go to the source.
A better design would be a sol-centric orbital platform, say in Mercury's L-5 point, collecting solar wind via magnetic trap (the "ram-scoop" idea) and using an on board mass spectrometer to separate the components, which are then bottled for use, storage or shipping. In that orbit, there'd be sufficient solar power to run all that.
Set up a veritable merry-go-round of solar sail craft to go pick up and return the He3, and whatever else you want, and pay nothing in fuel costs. So what if they're slow. They're cheap. Build lots. Build *them* on the moon, or better, out of asteroids. You don't want these things slamming into Earth? Don't nuke 'em, smelt 'em.
Gerard O'Neill gave us lots of good ideas. We'd do well to remember that he didn't get them from professional scientists and engineers with reputations to make and maintain. He got them from undergraduates, whose class project it was to think these things up. Having a reputation to lose to your less foresightful colleagues sure puts a damper on innovation.
"I may be synthetic, but I'm not stupid." -- Bishop 341-B
Very informative comment off of SciScoop by RickyJames
Kulcinski and FTI have presented a graduate course entitled "Resources From Space" in 1996, 1997, 1999 and 2001, taught by a variety of instructors including Harrison Schmitt. Each of these have extensive notes and pdf files online, and probably are the best sources for data on the Internet on the topic of using lunar resources for energy. These two guys are the leading proponents of helium-3 use; if anybody is going to make a good case for this, it's them.
The key factor is the dilute nature of the helium-3 in the lunar regolith, and all the other stuff that's mixed in there with it. Schmitt estimates on page 19 of lecture 10 in the 2001 course that the He3 abundance is "up to 30 ppb" or 30 parts-per-Billion-with-a-B in the top 10 feet of lunar soil. Also embedded in the lunar soil is 30-180 parts-per-Million-with-an-M of hydrogen and 30 parts-per-Million-with-an-M of normal helium or He2.
So, say you want a ton of helium-3 from the Moon. You've only got to do two things.
Step one, heat up 1,000,000,000 / 30 = 33,333,333 tons of lunar soil. That's a lot of dirt and a lot of heat. All of the hydrogen and helium gas in the soil is baked off and captured. You get 2001 tons of hydrogen and helium - 1000 tons of hydrogen gas, 1000 tons of helium gas, and one ton of helium-3 gas.
Step two, you've got to separate the ton of helium-3 you want to ship back to Earth from the 2000 tons of normal helium and hydrogen you don't. Getting the hydrogen out is relatively easy; just combine it with lunar oxygen to make water. Try to avoid a titanic explosion in the process. Separating that one-in-a-thousand helium atom you want from the helium that's left, though, is hard. It's the same problem faced with the Manhattan Project people trying to separate the U-235 uranium atoms that could make a bomb from the U-238 uranium atoms that couldn't. You'd have to recreate wartime Oak Ridge isotope separation plants on the moon - and those aren't going to be built from lunar material, I assure you.
As a point of interest, coal strip mines in the West get out 25 tons of coal for ever manhour of labor used. By this criteria digging up 33 million tons of moondirt per year would take 1.32 million manhours of labor. At 2000 manhours per year, that's a required crew of 660 miners for one ton of He3 per year.
You say we need 30 tons of He3 per year - that's the equivalent of 20,000 miners moving as much moondust around as the entire U.S. coal mining industry mines in coal in a year. I know, I know - the situation isn't comparable, NASA would create a super-automated unmanned bulldozer fleet, etc. etc. Running on what? Costing what? Getting to the moon how? None of these are impossible factors, only impractical ones.
Then, there's the question if a fusion reactor could ever be built that would use helium-3. Sure, it sounds good. But we haven't even built a deuterium fusion reactor yet, and the physics of that is a LOT easier than getting a helium-3 reactor to work. In the 1950s fission reactors were going to be cheap and simple, too. Remember "electricity too cheap to meter"?
I dunno, Sylvia. It sure sounds good to say, here comes this shuttle with a one ton can of helium-3 on board back from space that's landing on the runway to solve all of our problems (for two weeks - you need 30 tons per year, remember?), wave the flag and strike up the band. But when you look at what it takes in infrastructure to get that helium in the can on the moon, and what kind of infrastructure you're going to pour it into once the can is offloaded and the band's gone home, well, it's just not quite so attractive to investors. Especially as long as they kn