After browsing the internet for some time, I still haven't found an answer
to the following question.
As a novice in this area, I wonder why there is such a specific preference
for having e.g. ISS, Space Shuttle in an orbit of about 400km. (This I
make up from the testimonials from space ships' crew that all tell about the
sun coming up and going down every 1.5 hours).
So my question is, why this preference for 400 km and why isn't it an orbit
of 250km or 600km or even more ?

Maarten


Its about the highest the shuttle can go with much useful payload, and the crew
is protected from the radiation belts too.

Actually ISS would be easier to maintain in orbit if it were higher, but then
we would have no way to get a crew to the station so it doesnt matter.
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My opinion is right