Astronaut's underwear shirts

[Feuerfresser]

Hey there,

I have a very special question
You can see different colours of shirts Astronauts wear under their flightsuit.
Does this have a special reason (for example depending on their military duty)?

Thanks

[NASAgeek]

Not that I know of. except in some pictures on station or shuttle you see astronaut's shirt saying a particular branch of military or college . I think the nameplate on the astronauts flightsuit shows if they are military or not.

[Phoenix PK]

Good question. Red and yellow seem to be the most significant, if there is anything to it.