For starters ... all who want to westpoint. To go to the point you need a recommendation from either sitting congressmen/senator, or a "career" officer of note in the US armed forces. Westpoint is not open to just anyone with the grades. You very literally have to know people in high places.

http://www.usma.edu/admissions/sitepages/apply_nominations.a...

https://en.wikipedia.org/wiki/List_of_astronauts_educated_at...

(That's just the easiest to research. If you dig into most astronaut's backgrounds you can find prominent people who helped them along.)