Hmm… scientists are now saying "unequivocally" that they've discovered considerable amounts water on the moon's south pole after bombing the region with a satellite last month and kicking up debris. I've always wondered what the big deal with water on the moon is. Why should we care? The New York Times gives a partial answer that's mildly satisfying:
The confirmation of scientists’ suspicions is welcome news both to future explorers who might set up home on the lunar surface and to scientists who hope that the water, in the form of ice accumulated over billions of years, could hold a record of the solar system’s history.
But there's an even more intriguing answer in this old New Scientist piece: If there's water in the moon, astronauts could someday harvest it to generate hydrogen for fuel—say, in order to blast a ship out toward Mars. Since there's less gravity on the moon, it's easier to launch a probe to Mars than it would from Earth. "It's like building a transcontinental railroad to space," says one expert. And after that, maybe we can bomb Mars, find water, and off we go again…