Our astronaut, Frank De Winne, at this very moment, aboard the International Space Station, is a brilliant F16 pilot, who served in Kosovo as Squadron Leader. He received the Joe Bill Dryden Semper Viper Award for having managed to save a F16 that was doomed to crash (first non-american, apparently). He also, earlier, ejected from a plane.
This morning, he admitted to listeners (school children) that he had fear of hights,sometimes, to everyone's surprise!
Las night, I attended a conference at the University of Antwerp; professor Laurence Young who works on various space related experiments meant to study vertigo and dizziness, said that apparently, spacewalking above a convex structure like the ISS or MIR makes you more dizzy than above a concave structure like the Shuttle's payload bay. That's why Linenger felt like free falling for several seconds, even though he had already spent months aboard Mir before going outside.

Raoul