Diamonds in the Sky

China's successful antisatellite-missle test Jan. 11 carries potential implications for the international community, which has collectively placed at least 316 satellites within the missile's proven range (528 more orbiters, such as GPS and early-warning satellites, fly even higher). At issue are military surveillance satellites--the very ones that detected Beijing's test--which represent only 6% of the total number but almost all of which fly within reach. Until now, only Russia and the U.S. have downed space objects, and despite Beijing's assurances that the test was not adversarial, the U.S. sees a threat to its spy satellites--and a possible catalyst to a space arms race. [This article consists of a complex diagram. Please see hardcopy of magazine.]