Space crews are heterogeneous - a diversity that is the product of picking the best from all over the world. For some years, research has also been focusing on the effects of multi-nationality on crew interaction and possible tensions and misunderstandings. Helmreich and Merritt (1998) emphasise that cultural differences are potential threats to safety, performance reliability, and interaction between crew members. In fact, accident investigations in aviation consider culture as a factor, particularly as one that has an impact on communication.
Sandal, G. M. (2001) Psychosocial Issues in Space: Future Challenges. Gravitational and Space Biology Bulletin, 14(2), 47-54 (photo via)