Adjusting the hypobaric chamber's pressure setting, Air Force Staff Sgt. Andre Scott gradually duplicates the conditions of higher altitudes. When the altimeter reads 54 mmHg, which is an altitude of 60,000 feet, a cylinder of water in the chamber boils. Here at the Brooks City Air Force Research Lab in San Antonio, Texas, scientists and technicians are studying the upper atmosphere's extreme conditions, and the equipment and training needed to keep pilots safe. That includes having pilots remove their masks during simulations in the chamber. "You can get dizzy and for a lot of people their skin starts to turn blue," Scott says. "We want them to experience their symptoms so if it happens to them, they know what they're looking for."