Actually, much of what NASA does IS beneficial in that area. Why do you think fuel cells were developed? Internal combustion engines don't work in space - no oxygen.

And quite frankly, the missle defense system is useless. Russia wouldn't launch, and the rest of the world's nuclear nations don't have a large enough stock pile to defeat us. We however can easy crush them.

What we do have to worry about is is somebody trucking a nuke into a major US city and touching it off. No missle can defend against that.