Optical computing: A field in flux

War has broken out. A thousand missiles thunder off their launch pads halfway around the world, from a country hell-bent on destroying the United States. Only 25 minutes - 1500 precious seconds - remain to destroy them before they reenter the atmosphere over their targets. By then the number will have multiplied into as many as 10 000 warheads, many of them live nuclear heads, some decoys. How can they all be individually tracked and the live warheads annihilated in space before they hit their targets?