So I have this character who always wanted to be an astronaut, but I need a reason she can't be.
I've done some research, and I've found what the basic physical requirements for being an astronaut are, but the only specific rules I could find were 20/20 vision and BP not more then 140/90 (there's a height requirement as well, but she fits that) The vision isn't much of a deterrent because she could have LASIK. The sites I've checked don't really mention more then the initial screening tests, but I figure there are obviously some hard-core fitness requirements as well.
I need an injury or ailment that only becomes apparent when she's a college sophomore (though it could be something pre-occurring that only gets worse then, if something showing up completely out of the blue is unrealistic). It can't be something that will affect her day-to-day life to a huge degree, though it's okay if it affects her a little.
She played field hockey in high-school and college (so it could be an injury from that, but not a medical ailment that would have prevented her from playing) and it can't affect her hands, because she's a musician. And it has to be something major enough that she gives up on being an astronaut almost immediately, not something that only becomes apparent as a barrier later.