Here is a bit of trivia about Alan Shepard.
When he went up in space, Alan had some sensors placed at various places on his body. To mark where the sensors were to be placed, for some reason it was decided to tattoo marks on Alan's body.
For the rest of his life, he had these permanent tattoos of the sensor location on his body.
I guess NASA did not have any magic markers.
It is commonly understood that the reason that Chuck Yeager could not be an astronaut was because he did not have a college degree.
Which of the original seven Mercury pilots did not have a college degree but still went into space?