But on the face of it, it looks like maybe 320 or so NASA astronauts have been to space - out of 340 trained - which makes it seem like maybe 94% of them finally got into space. read more
Astronauts are in space very little of their careers; don't know the actual percentage. The majority of their time is spent in assignments generated by the Astronaut Office, often working operations issues and/or participating in design, development, test and evaluation of space systems as crew representatives. read more
He became the unofficial leader of the astronauts, and continually worked with them. Fortunately, Slayton would get to space. He managed to get selected for the Apollo-Soyuz test project in 1975, and finally, after over a decade of waiting, reached outer space. So, actually, he fails to make your list. read more