The Kármán line represents the theoretical altitude where Earth's atmosphere becomes too thin to support aerodynamic flight. To generate enough lift at this altitude, an aircraft would have to travel faster than orbital velocity. It serves as the internationally accepted boundary between aeronautics and astronautics.
Heard on the job
The suborbital flight crossed the Kármán line, officially earning the crew their astronaut wings.
Insider tip
The US military and NASA often use an 80-kilometer boundary for awarding astronaut wings, differing from the FAI's 100-kilometer standard.