April 13, 2009
the edge of space
The edge of space has been newly confirmed at 73 miles above the earth.
A lot remains very fuzzy, however, as the boundary is surrounded by a host of misconceptions and confusing, conflicting definitions. For starters, astronauts can say they’ve been to space after only passing the 50-mile (80-kilometer) mark.
Meanwhile the boundary recognized by many in the space industry is also a somewhat arbitrary 62 miles (100 kilometers). Scientist Theodore von Kármán long ago calculated that at this altitude the atmosphere is so thin that it’s negligible, and conventional aircraft can no longer function because they can’t go fast enough to get any kind of aerodynamic lift. This 62-mile boundary is accepted by the Federation Aeronautique Internationale (FAI), which sets aeronautical standards.
NASA’s mission control uses 76 miles (122 kilometers) as their re-entry altitude because that’s where the shuttle switches from steering with thrusters to maneuvering with air surfaces, NASA states. Others point out that the “Now Entering Space” sign should be posted way out at 13 million miles (21 million kilometers) because that’s the boundary where Earth’s gravity is no longer dominant.
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I wonder if it smells funny.
ah, well, c’mon, it’s *all* space, even in yer basement.