While I doubt that anything could stop a truly determined and well equipped adversary, I would frankly not be shocked if the whole thing was basically packed in claymores facing out, just for starters. You won't care in that extreme about compromising the physics package; you'll already be scrambling every resource including NEST to the site. You just want to buy time, and there are a lot of ways you could do that.

Hell, maybe they include an EPFCG... that would be really clever.