Like the Soviet Union and the U.S. during the Cold War, Beijing is using its space ambitions as a powerful ideological—and even expansionist—tool of statecraft. In January, China successfully landed Chang’e-4, a small base station and rover, on the far side of the moon, becoming the first nation to touch down in that unseen hemisphere. “We are building China into a space giant,” Chang’e-4 chief designer Wu Weiren said at the time.

Last year, Ye Peijian, the leader of the country’s lunar program, described the agency’s work by invoking Beijing’s growing dominance across the South China Sea islands: “The universe is an ocean, the moon is the Diaoyu Islands, Mars is Huangyan Island. If we don’t go there now, even though we’re capable of doing so, then we will be blamed by our descendants.” That may just be celestial saber rattling, but it’s gotten the attention of Western observers. “I have no doubt that within the next five years, they will complete [their own space station] and announce a manned lunar program,” says Joan Johnson-Freese, a professor of national–security affairs with expertise in space, science and technology at the Naval War College in Newport, R.I…

All the lunar competitors are eyeballing the same spot on the surface: the south pole, which is as close to a fertile crescent as exists on the moon. The southern craters, cast in permanent shadow, are home to plentiful deposits of water ice, which could be used to sustain humans and their crops. The water can be broken down into oxygen, which can then be used as atmosphere for crews, and hydrogen, which—recombined with the oxygen—can make a simple, powerful and clean rocket fuel. Wrestling water and rocket fuel off Earth for a deep-space mission is a lot harder and more labor-intensive than carrying it up from the moon, where the gravity is one-sixth that of Earth, and then parking it in lunar orbit. Spacecraft on their way to Mars could, in theory, stop by the moon to top off their tanks before lighting out for deeper space.