In a previous article, "Mike Rapoport" said:
I think space begins by agreement at 100km or something like that.

http://www.space.edu/projects/book/chapter3.html
Surely you say, some international body must have declared where space
begins. International law states that there is no definitive point where
the atmosphere ends and space begins. The major space powers accept the
following definition: Space begins at " the lowest perigee attained by
orbiting space vehicles..."

--
Paul Tomblin http://xcski.com/blogs/pt/
It's distinctly sub-optimal having a 70MPH pigeon explode all over
the inside of your vehicle.
-- Tanuki