Selective breeding of astronauts

Ok, if you were going to make a better astronaut for extended space flight, how would you do it.
Well he/she would need a really big brain, to solve the problems that they would encounter on their multi lifetime voyage, because they would have no help (big heads are needed for really bigger brains). They would need only 1 to 5 percent of their muscles in a weightless environment, (thin bodies, almost anorexic looking). Interstellar space is dark, so they would need really big eyes to gather light that is billions or trillions of miles away.
Big brain, small body, big eyes…
Fiction or future astronaut, forced evolution could achieve every one of these things, not that gene splicing or similar process not yet discovered could not.