It used to be that they sent only the exceptional to space, but now they remain behind. We travel farther now, and technology needs to be tested. No sense wasting the exceptional on a collision with space junk. Their talents are better used assessing our successes and failures and planning for the future.
Not that they send just anyone up now. We are skilled and intelligent people, capable of complex thought and innovation. James, for instance, is an excellent physician and scientist. His knowledge and tools come from having studied with exceptional minds. Likewise, my computers and ship are the products of brilliance, and in all but the most extreme situation my skills are enough to handle them.
We call this policy the "One step above a trained monkey" space exploration. The administration discourages this, preferring to use terms like "maximizing the candidate skills pool," but they miss the point. We like monkeys. And we've dreamed of space since childhood.