Authors Kleppner, Lamb, and Mosher report on an excellent APS study that provides a wealth of data and analysis. Especially new are the array of possible maneuvers during the boost phase of intercontinental ballistic missiles (ICBMs) and the problems those maneuvers pose for a boost-phase intercept (BPI) system. My judgment from the report itself of the utility of BPI against North Korean ICBMs, however, is more positive than are the executive summary and press reports of the APS study.
For instance, according to an earlier Physics Today story ( Physics Today 0031-9228 56
If the US Department of Defense decided to deploy within four years a system using large surface-based interceptors against North Korean ICBMs, the US could likely expect at least several years of protection.
Necessary? Maybe not. Feasible? Yes. And that is not the end of the line for boost-phase intercept. Simple geometry shows that airborne radar at altitudes typical of modern airline jets (12 km) will see to the ground at a range of 400 km, adding important tens of seconds to the time available for intercept by a ground-or sea-based BPI system.