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Forum:	Commercial Space - Military Space
Topic:	[Discuss] Virgin Galactic Unity 22 crewed flight

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Your Reply: HTML is ON UBB Code is ON Smilies Legend	[QUOTE]Originally posted by Robert Pearlman: [B]Unity 22 peaked at 53.5 miles (86.1 km). It was the U.S. Air Force, rather than NASA, that came up with the 50 mile (80 km) demarcation in the late 1950s, such that by the time Alan Shepard and Gus Grissom flew, they became the first to receive military astronaut wings. Both 50 miles (80 km) and 100 kilometers (62 miles), the latter the Kármán line, were somewhat arbitrary numbers. In the decades since they were chosen, science has pointed to the earlier being [URL=https://www.newyorker.com/news/daily-comment/richard-bransons-plan-to-beat-jeff-bezos-to-outer-space]the more accurate boundary[/URL]. <BLOCKQUOTE>[i]Jonathan McDowell, an astrophysicist at Harvard, had been exploring the same question. In October of 2018, he published an article in Acta Astronautica, a peer-reviewed academic monthly, titled "The Edge of Space: Revisiting the Karman Line." He drew on history, explaining how, in the late fifties, the U.S. Air Force began awarding astronaut wings to pilots who flew above fifty statute miles, and how fifty miles was not only a "nice round figure" but also "the right choice from a physical point of view" because the mesosphere starts about fifty miles above sea level. McDowell made a scientific argument, too. As von Kármán had done, he contended that our notion of space should begin wherever orbital dynamics exceed aerodynamic forces — wherever an airplane can no longer operate like an airplane — and demonstrated that, based on ballistic coefficients and modern atmospheric models, fifty miles is a "suitable choice to use as the canonical lower 'edge of space' in circumstances where such a dividing line between atmosphere and space is desired."[/i]</BLOCKQUOTE>[/B][/QUOTE]
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