[ Sounds like this kid's from a world - or just time? - when no planets besides Earth are viable places to live, which is strange from Jim's perspective. Starbases and the like aren't considered colonies, but other planets are. But-- ]

It's just some dumb old terran phrase, to avoid jinxing yourself. I have no idea what the etymology is.

[ Uhura would know, he thinks before he slaps the thought away. No use agonizing over his crew. ]

Take care of yourself, alright? I'm gonna do another sweep to see if anyone's stuck.