Eighty-five percent of the rocks on the surface of the lunar highlands are anorthite, which contains aluminum as well as a massive supply of oxygen. Smelting aluminum in the quantities necessary to construct and maintain Artemis would produce so much excess oxygen—eight atoms for every two of aluminum—that they would be constantly venting it.

For every kilogram of payload, you need an additional 3.73 kilos of fuel. So a one-way ticket to the moon is calculated to eventually cost about $33,000.

Moon, Mars or Asteroids for colonies

Where will humans live in space? That was the focus of a good-natured debate that took place at this week's "New Space Age" conference at Seattle's Museum of Flight.