The poles have areas of perpetual sunlight and perpetual shade. The sunlight would be useful as a source of solar power for colonists. The shaded areas may feature deposits of ice that have been locked up for billions of years.

Such ice could be used not just as a source of water. Through electrolysis, it could be broken down into hydrogen and oxygen. The oxygen could be used both for respiration and to make rocket fuel for trips back and forth to Earth. But there’s no definitive proof ice is there. The possible presence of water on the moon “is a hotly and passionately debated topic,” Tooley said.