Learn this word: Chang'e

In China, 13 designers are competing to draw up plans for a lunar rover. China's Chang'e project will launch a satellite into earth orbit. That satellite will launch another satellite that will go into moon orbit and provide 3-D maps and analyze the moon's chemical composition to figure out how it could be useful to pioneers living there.

Later, China will send an unmanned rover to the moon that will drill core samples and send them back to earth. The goal is to do this by 2017. Then China will decide whether to send people to the moon.

What's the over-under date for when the conventional wisdom holds that there is no longer one superpower, but two?