As for the young character, she's an adolescent (11-14ish?) brilliant engineer who could have risen to greatness. Unfortunately for her, she was raised on the streets, all of her smarts honed to illegal acts of increasing skill. When she's caught escaping her 5th juvenile criminal facility, she's offered a choice for the future. Waste in prison due to an extended sentence, or join the crew of the Monroe. If she can live to adulthood,  her record will be sealed. She doesn't know it, but the Council is using her as a guinea pig to test the effects of long term space travel in human children. 

That's basically the idea.