Reply #5: Besides, He-3 is not geologically (lunarogically?) concentrated

[Dudley_DUright]

but instead uniformly spread over the surface of the moon. It is economically ridiculous to try to mine He-3 on the Moon. I for one don't want to see massive strip mines on the Moon, even though I am sure Bushco would love it. The following article outlines the basic problems:

<snip>

Indeed for now, the economics of extracting and transporting helium 3 from the moon are also problematic. Even if scientists solved the physics of helium 3 fusion, "it would be economically unfeasible," asserted Jim Benson, chairman of SpaceDev in Poway, California, which strives to be one of the first commercial space-exploration companies. "Unless I'm mistaken, you'd have to strip-mine large surfaces of the moon."

While it's true that to produce roughly 70 tons of helium 3, for example, a million tons of lunar soil would need to be heated to 1,470 degrees Fahrenheit (800 degrees Celsius) to liberate the gas, proponents say lunar strip mining is not the goal. "There's enough in the Mare Tranquillitatis alone to last for several hundred years," Schmitt said. The moon would be a stepping stone to other helium 3-rich sources, such as the atmospheres of Saturn and Uranus.

<snip>

more...

http://www.space.com/scienceastronomy/helium3_000630.html