The Kármán line is an attempt to define a boundary between Earth's atmosphere and outer space, which is important for legal and regulatory purposes: aircraft and spacecraft fall under different jurisdictions and are subject to different treaties. The Fédération Aéronautique Internationale (FAI), an international standard-setting and record-keeping body for aeronautics and astronautics, defines the Kármán line as the altitude of 100 kilometres (62 miles; 330,000 feet) above Earth's mean sea level. Not all organizations recognize this definition. The US Air Force and NASA define the boundary as 50 miles (80 km) above sea level. International law does not define the edge of space, or the limit of national airspace.The Kármán line is named after Theodore von Kármán (1881–1963), a Hungarian American engineer and physicist who was active in aeronautics and astronautics. He was the first person to determine the altitude at which the atmosphere becomes too thin to support aeronautical flight, which Kármán calculated as 83.6 km (51.9 miles). A vehicle above this altitude would have to travel faster than orbital velocity to derive sufficient aerodynamic lift to support...