Lee's parents and their business partner, Gordon, found a class A habitable planet. They thought their quest as explorers was over and they'd live a life of ease. But before they could return and register their claim, Lee's parents died doing a survey of the surface. That left Lee two-thirds owner of the claim and their partner Gordon obligated by his word with her parents to raise Lee. She had grown up aboard the ship with her uncle Gordon and he was the only family she'd ever known. Him adopting her was an obvious arrangement to them. Other people didn't see it so clearly over the picky little fact that Gordon wasn't human. 

After finding prejudice and hostility on several worlds Lee was of the opinion planets might be nice to visit, but terrible places to live. She wanted back in space exploring. Fortunately Gordon was agreeable and the income from their discovery made outfitting an expedition possible. Lee wanted to go deep-out where it was entirely unknown and the potential prizes huge. After all, if they kept exploring tentatively they might run up against the border of some bold star faring race who had gobbled up all the best real estate. It wasn't hard to find others of a like mind for a really long voyage.