i can't remember if we put an exact timeline on it, but they've definitely known each other for an extremely long time. i'd say most likely more than 10 years, at the minimum. but thane is a scientist and doctor, he's had a clinic on terminus for a few years serving those who live in nova heights. he was in the alliance for a while before he left with a lot of blackmail on higher level people (as he has eidetic memory, so he's a walking recorder at all times). he's now the science officer and medic for the dauntless.