Hi All

Percentages are definitely better than ppm... Since the Moon has He3 and other interesting atoms trapped in the regolith, water baked from regular regolith is better as a by-product of extraction than as the chief product, except at the Poles.

From my point of view, thinking in Solar civilization terms, I think we'd be better off in the long term mining He3 from Mercury because its field will have concentrated He3 around the Poles, near the ice that we know is there in much bigger quantities than the Moon. Mercury also has much higher equatorial solar power densities than the Moon, and since it is deeper down the Sun's gravity well it can flick things [via mass-driver] to the rest of the Solar System with shorter transfer times than the Moon, and shorter lag-times between launch windows.

Also Mercury has a core that is much closer to the surface than Earth or the Moon, and it's not inconceivable that it could be mined, especially at deep crater depressions near the Poles. The recent core-probe suggestion - though tongue-in-cheek - is even more feasible on Mercury.

The recent cancellation of the BepiColombo Mercury lander is a short-sighted decision that needs to be reversed, as I am sure Raoul will agree.

Adam