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Virgin Galactic flights surpass threshold of space -- as defined by NASA, FAA
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Media covering Virgin Galactic flights often say the VSS Unity spaceship flew to “the edge of space,” but that may be a spaceflight misnomer.
The confusion likely reflects the internationally accepted boundary between Earth’s atmosphere and outer space, generally referred to as the “Karman line.” That boundary — named after Hungarian-American engineer and physicist Theodore von Karman (1881-1963) — defines space as 62 miles above sea level.
It’s recognized by the French record-keeping body Federation Aeronautique Internationale as the official boundary for space.
But U.S. government agencies, including NASA, the Air Force and the Federal Aviation Administration, consider space to start at 50 miles above sea level, awarding “astronaut wings” to any pilot who has flown beyond that point.
That’s unofficially referred to as the “McDowell line,” named after Jonathan McDowell, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics. McDowell has authored influential scientific papers that state there is no significant difference between the space environment at 50 miles and 62 miles above sea level.
All of Virgin Galactic’s flights have surpassed the McDowell line.
On Friday, the Unity climbed to a flight apogee of 54.3 miles, traveling nearly three times the speed of sound after the spaceship detached from the mothership and fired up its rocket motor to shoot into space.
