What altitude do I need to be to register as being above a biome?
In KSP, I can do science "from space just above Kerbin's Deserts" or "while flying over Kerbin's Water".
At what altitude do I stop "flying over" and start sciencing "from space just above"? At what altitude am I "in space near Kerbin"? In other words, how low do I have to be for the biome to register?
Moreover, for the Mun (or other biome-bearing body), how close do I need to get in order to register as in "space just above" or "flying over" the Mun's highlands, for example?
Science in Kerbal Space Program knows five corridors:
- On the Ground
- Lower Atmosphere
- Upper Atmosphere
- Near Space
- Outer Space
Note that only sub-orbital flights will be considered atmospherical, even if the altitude is inside the given corridor - aerobraking is considered "Near Space" even if below the threshold.
That said, the threshold depends on the body:
On Kerbin (left), anything below ~18km of altitude will be considered flying over (that is, Lower Atmosphere). Outer Space on Kerbin starts at ~250km. The shift from Upper Atmosphere to Near Space is the edge of Kerbin's atmosphere (~69km), and (as detailed above) may depend on the trajectory.
On the Mun (middle), there is obviously no atmosphere. Here, the Outer Space to Near Space transition is at ~60km.
And, for good measure, the same as for the Mun also applies for Minmus (right), but here the threshold is at ~30km.