The intercept lab — boost, midcourse, glide and terminal
Why intercepting a ballistic missile is hard, phase by phase: the boost window that detection and a decision consume, the absentee ratio that puts a space layer's cost in the thousands, the horizon a glide vehicle stays under, and the ground a terminal battery can actually defend.
Every figure is arithmetic rather than a claim about a named system, and the footprint formula is checked against the published radius of two deployed batteries.