vanderberg air force base. this is possibly the most important test the u.s. has ever done. is that right? >> i think undeniably the most important test of the missile defense system that the u.s. has ever under taken. that's because it is the first time that the u.s. will try to knock down an intercontinental ballistic missile similar to the one north korea is developing and according to officials is well on the path to having fully developed. they believe the north koreans will be able given the pace of their current testing to hit the u.s. with a nuclear war head within a matter of a few years. so what the u.s. will do today is launch an icbm out of the marshal islands in the pacific ocean. a few minutes after that launch from here. they'll launch the intercepter missile which they hope will then strike the icmb in space above the pacific and destroy it.