Colors of Space (version 2), The by Marion Zimmer Bradley (1930 - 1999)

Young Bart Steele’s father is dead. A mysterious stranger tells him his life is in danger, and hands him a ticket aboard a Lhari star cruiser to an unknown destination. He gets on, not knowing where he is going, or why... A fantastic kid’s adventure from sci-fi master Marion Zimmer Bradley. ( Summary by Mark Nelson )