The Pentagon is exploring options to harden protection of radars in the Ballistic Missile Defense System from attack against hypersonic glide missiles and is planning new "activities" to demonstrate increased protection of select sensors critical to the $180 billion missile shield. Missile Defense Agency Director Lt. Gen. Sam Greaves told a Capitol Hill audience Sept. 4 that senior Defense Department officials are concerned about the potential vulnerability of the BMDS, which includes a handful of major radar systems at fixed...