"A moon colony is a waste of money" — Is it?

Washington (CNN) -- Newt Gingrich has absorbed a fair degree of ridicule for his campaign proposal to build an American colony on the moon.

Before focusing the laughter solely on Gingrich, however, let's recall that it is the declared policy of the U.S. government to return a human being to the moon by 2020, in preparation for sending a human astronaut to Mars. If Gingrich is wrong (and he is), he's not wrong alone.

As you read this, an international space station is orbiting Earth, staffed by a crew of six (currently, three Russians, two Americans and one astronaut from the European Union). Cost to date: $100 billion.

American's space agency, NASA, is developing a next-generation rocket capable of lofting human crews. The rocket remains on the ground, but its development costs have soared, from a projected $28 billion to $44 billion.

And the purpose of all this commotion and expense?

It's very hard to answer. Read More