Carstairs (geologist)

From Memory Alpha, the free Star Trek reference

You might also be looking for the USS Enterprise-D engineer named Carstairs.

Carstairs was a 23rd century Starfleet geologist serving aboard the USS Enterprise.

In 2268, Carstairs was selected to be in the landing party to Alpha Carinae II by the M-5 computer but not by Captain Kirk. This was because M-5 knew that Carstairs had once visited the planet while being with the Merchant Marines. (TOS: "The Ultimate Computer")