Pilots can shoot video of the scenes below them using standard cameras, infrared sensors that pick up body heat and light sensors with enough resolution to show building features, basic vehicle features and movements such as people walking or riding bicycles. The planes also can carry technology that mimics cellphone towers, enabling agencies to track people’s cellphones even if they’re not making a call or in public. Much of the technology was developed for use by the U.S. military in Iraq as part of a project dubbed Gorgon Stare after the mythical Greek monster that could turn men to stone with a glance.