Star Wars in transition

The present status and possible future course of the Strategic Defense Initiative are described. The present proposal, which calls for four types of space-borne and ground-based sensors to track hostile missiles and their warheads throughout their half-hour trajectory, is discussed. Also examined are the boost-phase system for space-based interception, survivability of the entire system, distinguishing warheads, and software and algorithms. The prospect for further advances and the hard choices faced by the Bush administration are considered