The purpose of this chapter is to examine how people's relationships with one another may affect the psychological functioning and welfare of the individual astronaut and the performance and morale of the entire crew. The primary focus is on crews that are "small" in the sense that each crewmember has the opportunity to interact with each and every other crewmember on a person-to-person basis. The two-person groups (dyads) and three-person groups (triads) that have completed space missions thus far qualify as small groups, and so do the crews of six members or so that are considered appropriate for the Space Shuttle and for the first interplanetary missions (Stockton and Wilford,1981).
During initial years of the space program, psychological concerns centered around the effects of weightlessness on astronaut performance, and upon man-machine engineering (Gerathewohl, 1959). By the mid 1960s, however, interests had expanded to include social psychological variables. Over the following decade, a number of theoretical papers and reviews appeared, the most salient including those by Berry (1973a); Haythorn, McGrath, Hollander, Latané, Helmreich, and Radloff (1972); Helmreich, Wilhelm, and Runge (1980); Kanas and Fedderson (1971); Kubis (1972); Rawls, McGaffey, Trego, and Sells (1968); Sells (1966); and Sells and Gunderson (1972). These reviews firmly established interpersonal and group variables as important determinants of crewmember performance and well-being in space.