"High-Altitude Low-Opening (HALO) is a daredevil form of parachuting developed by Ekaterina scientists for spying. Planes fly high up in the air above enemy radar, and Ekaterina agents. They free-fall and open their chutes so close to the ground that they are able to avoid radar detection. The record for the longest HALO jump was set by Colonel Joe Kittinger, who jumped more than 19 miles to the ground. (That's more than twice the height that airlines fly.) No one is sure whether Kittinger is a member of the Ekaterina branch or the thrill-seeking Tomas."