Kármán line

See also: Karman line

English

Named after Hungarian-American engineer Theodore von Kármán (1881–1963), who calculated this limit.

(aeronautics, astronomy) The altitude at which the atmosphere becomes too thin to support aerodynamic flight.
- 2020, Stephen Hawking, Lucy Hawking, Unlocking the Universe‎, Penguin UK, →ISBN:
  As well as being important for aircraft and spacecraft, the Kármán line is useful for lawyers—the laws that govern space are not the same as the laws that govern Earth's atmosphere!
- 2021 July 11, Sarah Betancourt, “Virgin Galactic to launch space plane with Richard Branson onboard”, in The Guardian‎:
  The boundary between Earth’s atmosphere and outer space, known as the Kármán line, has been a source of controversy for years.

This is treated as the border between the Earth's atmosphere and outer space. It is defined as a static altitude of 100km (62 mi) above sea level (ASL) on Earth by the Fédération Aéronautique Internationale; the U.S. government (NASA, USAF, FAA) treats this as a static altitude of 50 mi (80km) ASL. The actual altitude is dynamic and not static, and depends on atmospheric conditions. Where both the 100km and 80km limits are used at the same time, the 100km limit is the Karman line and the 80km line is the McDowell line.