A key component of an air-launched missile defense system demonstrated its ability to acquire and track a ballistic missile target in the boost phase, according to Raytheon.

日前，一种空射导弹防御系统的关键组成部分成功演示了对助推段弹道导弹的截获与跟踪能力。

youdao

Boost-phase defense, which is necessary to counter such a threat, was not technologically feasible at that time.

CENTERFORSECURITYPOLICY: Multilateral madness

Particularly noteworthy in this regard, is the decision to all but cancel the promising Brilliant Pebbles space-based interceptor technology at the very moment that the Israeli government and the Western European Union (among others) are recognizing the indispensibility of the sort of boost-phase defense afforded by such a system.

CENTERFORSECURITYPOLICY: Center for Security Policy | So Much For ��The Vision Thing��: Clinton-Aspin Defense Budget Is Risky Business

And then something that they would call the boost-phase missile defense, which would be ways of shooting down missiles when they're at their sort of most vulnerable phase of flight.

NPR: Missile Defense, the U.S. and Europe