Despite our understanding of how team training works on Earth, a big leap is required to extend this paradigm to the unprecedented demands of a mission to Mars. The challenge of our time lies in creating training systems to sustain effective teamwork as flight crews venture further from home than ever before under isolated, confined, and otherwise extreme circumstances in long-duration space exploration (LDSE) missions. The goal of this chapter is to identify key developments that must be made to define an adequate model for understanding how team training may function in LDSE and how these teams can maintain effectiveness with minimal oversight. We discuss traditional guidelines and principles of team training, then highlight the shortcomings of current knowledge when transferred to the particular context and constraints of LDSE. The state of team training science, including its strengths and impending limitations, provide the basis for directing future research efforts to develop self-sufficient team training systems for LDSE.