When skeptics point out how expensive and unrealistic a Mars mission would be, proponents often reply, "What if Queen Isabel had told Columbus his plan has too expensive and unrealistic?" But George W. Bush's proposal that the United States mount a mission to Mars, throwing in a moon base to boot, is not like Columbus's proposal to explore the Indies—it's more like a 1492 expedition to the South Pole.
However bold, Columbus's westward journey from Spain to the Bahamas was not notably different from long ocean voyages that had already been undertaken by others, his destination was hospitable to life, and chances were he would find something of greater value to the throne than it had paid for his ships and stores.By contrast, a trip to the South Pole would have been dramatically longer and more difficult than any before—a phenomenally expensive and risky journey to a place hostile to life, where, even if he survived, Columbus stood little chance of finding anything of value commensurate with the voyage's cost. Isabel would have been a fool not to say. "This is too expensive and unrealistic."
At least, Spain would have waited until steam ships and other advances made a trip to the South Pole imaginable. And that realism points to the big question hanging over Bush's moon-Mars proposal: Why not wait until technology renders such travel less impracticable? There's no reason right now to go back to the moon, other than as make-work for aerospace contractors. For 30 years, the Nat...