Fifty years ago, the U.S. had the moon to itself. Starting in 1969, when the first of six Apollo missions touched down, it seemed likely that American astronauts would make a long-term home on the lunar surface. Instead, the U.S. sent its last manned mission there in 1972, and won't be returning anytime soon. That's a shame: The moon is now a more compelling destination than ever.
Other countries, seeing new scientific and commercial potential there, have started to fill the exploration gap, including China, Russia and Japan. Perhaps the most ambitious effort is the European Space Agency's "moon village," which is intended to be a permanent international outpost on the lunar surface. In recent weeks, the concept has gained considerable momentum as Europe's science ministers and private space companies have embraced it.
If the U.S. wants to join them, and resume its historic role as the leader in lunar exploration, it'll need a major shift in priorities.