[Robert A Cook PE]

No missile is credible.

200,000 feet up and 6,000 mph requires ABM technology. (And even our recent tests are only now getting close enough to go to phase 2 and consider deployment.

Internal sabatoge? (sp)

Certainly possible. Blow the tail or loosen a few tiles. Not likely, given the inspections going on on: those are white glove and fully smocked areas, almost impossible to get to without an inspector tagging along, or being caught by a later technician checking something else. (Nobody is going to "ignore" an "extra black box" stuffed haphazardly into the tail section or engine area.)

[Archangelsk]

Or the code in the onboard computer systems.