In the decades since the launch of Sputnik, the world has thrilled to the long-dreamed-of moon walks of the Apollo astronauts, marvelled at spectacular photographs of the outer planets brought to us by Voyager, and watched in horror as the Challenger exploded before our eyes. No longer the terrifying realm of science fiction, space has been hailed by popular culture as the "final frontier," the focal point of future exploration. Yet today there is...