i read a lot of tips on xbox.com and got it in under 10 tries.
first of all, turn up the brightness on your TV and in the game.
secondly, it doesn't matter what difficult you're on.
thirdly, shoot only the asteroids that are coming directly at the center glass panel. the ones that hit the sides (even the big ones!) will only inflict 1-2 pts damage.
other than that, keep at it! the sequence is random, and you'll eventually get an easy run.
and for those that can't seem to get mile high club, have you looked it up on youtube?
there's a distinct pattern that works every time if you time your flashbangs just right.
at the moment, my hardest achievement is playing a game other than fallout 3!