a cutting-edge shield meant to protect the united states from a sneak missile attack using lasers an unmatched radar technology is what the pentagon promised for a 10$10 billion investment, $10 billion worth of projects that critics now call a total flop and say left the united states dangerously exposed. were all your tax dollars wasted? cnn's brian todd has been digging into this story. what are you finding out? >> wolf these missile defense shields were impressive on the drawing board and had some flashy names like the multiple kill vehicle. but according to one report they were expensive, impractical, and some experts say they never should have been built. it's massive. 26 stories high weighs 50,000 tons and sits on top of a modified drilling platform. it's called the c-based x band