ABSTRACT
This chapter focuses on airborne boost-phase defences because, with some notable operational limitations, they are attractive for Theatre-Missile Defence (TMD), and an effective national defence against emerging ICBM threats. Boost-phase ballistic-missile defence is attractive because rocket boosters are easy to detect and track; they are more vulnerable and easier to destroy than warheads; determining the defence has destroyed a booster is easier than it is for a warhead; and the entire payload can be destroyed in a single shot. Space-based lasers are banned for national missile defence by the ABM Treaty and for theatre-missile defence by the Second Agreed Statement in the TMD Demarcation Accords. The airborne-interceptor concept is based on a high-speed rocket employing a small kinetic-kill vehicle for a payload, which homes in on the booster's infra-red signature. Boost-phase BMD is the only active defence capable of handling countermeasures such as chemical and biological sub-munitions, as well as other sophisticated penetration aids that may defeat upper- or lower-tier TMD systems.
