A budget fight in the United States Congress, played out in closed-door meetings and cryptic exchanges on the Senate floor, has revealed the existence of a previously top secret "stealth satellite" programme, designed to create a new generation of American spy satellites that cannot be detected from the ground. The programme's existence has been known only to officials with the highest security clearances and senior senators and congressmen who sit on the committees that oversee intelligence budgets. It might have stayed secret a while longer, except for the growing vehemence of the policy debate among congressmen and senators over the...