That provides fans with at least something of an explanation for why Andorians are blue in the “Star Trek” universe, but franchise devotees may also be curious about the original design conception behind the aliens and just why, exactly, the powers that be felt compelled to make them blue in the first place. There is an explanation on this front as well, though whether it’s a satisfying one is up for debate.
The Andorians were originally created by script writer D. C. Fontana for “Star Trek: The Original Series,” and their overall design was ultimately cemented by makeup artist Fred Phillips. Fontana introduced the aliens in Season 2, Episode 10, titled “Journey to Babel,” but while she seemingly always intended for them to have blue skin, her reasoning is rather unclear. The original script for “Journey to Babel” includes a memo from Fontana regarding the Andorians’ makeup and costume design, and she makes particular note of their blue coloration. In the words of Fontana herself, “Andorians are pale blue. Because.”
Fontana’s memo suggests that she and the rest of the “Star Trek” team’s motivation for making the Andorians blue was purely an aesthetic choice meant to distinguish the aliens and nothing more. Superficial reasoning or not, however, this particular design decision resulted in the creation of one of the most iconic “Star Trek” aliens of all time.