In order to guard against surprise nuclear attack, America's Strategic Air Command maintains a large force of B-52 bombers airborne 24 hours a day. Each B-52 can deliver a nuclear bomb load of 50 megatons, equal to 16 times the total explosive force of all the bombs and shells used by all the armies in World War Two. Based in America, the Airborne alert force is deployed from the Persian Gulf to the Arctic Ocean, but they have one geographical factor in common: they are all two hours from their targets inside Russia.