Optimal Allocation and Effectiveness of Midcourse Interceptors in a Layered Defense

Adaptive preferential employment of interceptors in midcourse ballistic missile defense is considered. The defense discriminates decoys, with such discrimination characterized by a K-factor, and determines optimal intercepts and salvo structure in shoot-look-shoot scenarios. The attacker's strategy to determine proper allocation of warheads to targets of varying value in the presence of a defense is also described. Representative results are presented for the effectiveness of the preferential midcourse defense by itself and in conjunction with a random-subtractive boost/deployment phase defense tier. Quality of discrimination is by far the strongest determinant of performance; the ability to perform a shoot-look-shoot is also important. Inventory requirements for midcourse and boost-phase defenses are determined for missions in which target value saved is the goal, for representative defense parameters. Based on these results, the midcourse tier appears to be a necessary component of a cost-effective defense.