Our attempts to forecast the psychological and social dynamics of extended spaceflight have proceeded within a particular framework. This framework has been imposed by a set of assumptions, by a theoretical orientation, and by available data. Since this framework has left an imprint on each chapter that follows, we consider it important to make this framework explicit at the outset.
Three assumptions have guided our efforts. The first assumption is that psychological and social factors will become increasingly important determinants of the success or failure of future space missions. Indeed, we shall review some evidence indicating that our understanding of spaceflight technology has already outrun our understanding of technology's human users. A goal of the present effort is to draw the reader's attention to the kinds of psychological and social issues which may prove critical during the coming generations of manned flight.
Our second assumption is that it is essential to avoid a premature commitment to a narrow perspective. Instead, it is necessary to entertain as many potentially viable alternatives as possible. The old ways do not necessarily remain the best ways, given rapidly changing technology, societal change, and likely shifts in mission specifications and goals. For example, early flights were modeled along military or paramilitary lines, and all astronauts to date have been highly trained professionals. Military models of organization may not prove desirable when astronauts are selected from a  heterogeneous pool of applicants, and not all members of large crews need be rigorously trained professionals. Future flights thus may require a careful weighing of model alternatives. Our corollary assumption is that no single plan will be desirable, or even workable, for all future missions. Optimal crew selection and training methods, habitability and communication specifications, and viable social structures will all depend upon such variables as crew size, crew heterogeneity, mission duration, and mission objectives.
Our third and most important assumption is that some of the uncertainties regarding life in space can be reduced through careful and rigorous behavioral and social science research. As we shall see, extreme care must be taken in extrapolating past findings to future spaceflight. Yet, however tentative, there does exist a research base that can provide useful information to the manned space program. Although this base may not always provide definitive answers to space-related questions, it can move us far beyond the point where we must rely entirely upon speculation.
Following Sells (1966) and the Space Sciences Board (1972), we have adopted a systems perspective on spaceflights. That is, missions are viewed as comprised of highly interdependent components (e.g., technical, biological, and social), such that variations in one component typically have repercussions in one or more of the others. We have attempted to expand this conceptualization by incorporating elements of open-systems theory as devised by J. Miller (1960, 1955) and advanced by Katz and Kahn (1966) and J. Miller (1978). Two important features of open-systems theory should be stressed. First, since open-systems theory can be applied to biological and social units of varying sizes, large-scale missions fruitfully can be analyzed in terms of component systems or subsystems. Second, by viewing systems as open, full acknowledgement is accorded the importance of the surrounding environment. Although space missions are separated from Earth by immense distances, mission-Earth transactions remain frequent and critical. For instance, a high rate of information exchange occurs during the course of all missions, whereas personnel rotation and resupply are likely on missions involving large, orbiting satellites. In addition, the preparation, launch, and recovery phases of spaceflight will involve intense spacecraft-Earth exchanges.
Although no attempt will be made to formulate data in systems terms, the interrelationships which are fundamental to the  open-systems approach will be basic to all discussions. Equally important, it is our intention to think in systems terms, i.e., to avoid categorizing and instead to search for "connectedness principles, isomorphisms, interrelationships - in short, a holistic approach" (Fisher, 1978, p. 96).
The Available Data
At present, relatively few data are available from space itself. In attempting to forecast some of the dimensions of life in space, behavioral and social scientists have concentrated on other environments with elements similar to those of space, i.e., those marked by isolation, confinement, deprivation, and risk (Kubis, 1972; Haythorn, McGrath, Hollander, Latane, Helmreich, and Radloff, 1972; Sells and Gunderson, 1972; Kanas and Federson, 1971). Thus, much of the data that has particular relevance to space comes from experiences in such settings as polar camps, underwater habitats, and space-capsule simulators of varying degrees of verisimilitude.
Since these environments approximate certain aspects of space conditions, relevant data will be given considerable attention both in this chapter and in the chapters that follow. We will refer to these environments as "space-like" or "similar to space." However, it should be remembered that they are not truly space-like; they merely approximate certain aspects of space. Indeed, a disclaimer underscoring the tenuousness of offered findings to the space environment is de rigueur in most original research reports, and in all serious literature reviews. There are two major shortcomings associated with much of this research. First, many studies have involved settings which lack the degree of isolation, confinement, and risk typical of long-duration spaceflight. Studies which have involved a high degree of isolation, confinement, and risk have often lacked methodological rigor.
Earth-space discontinuities- There are important discontinuities between isolated and confined environments that presently exist on Earth and those that are expected to predominate in space. Many of the studies cited in discussions of long-duration spaceflight involve subjects, tasks, and settings that bear little or no correspondence to those likely to be encountered in space. The results of such studies are not necessarily inapplicable to space, and repetitive findings that point to the same general conclusion may extrapolate quite well. Nonetheless, considering such studies, it is necessary to keep in mind the kinds of variables that could render generalization questionable.
 First, most studies of isolated and confined groups involve a very restricted range of subjects (all males, all college sophomores, all naval personnel, etc.). There may be appreciable differences between these subjects and the people who will participate in future space missions. In addition, most experimental (as compared with naturalistic) studies of isolated and confined groups involve subjects who are basically unacquainted with one another prior to the experiment. There may be substantial differences between such assemblages and the preformed groups that are likely to be sent into space.
Second, most studies of isolated and confined people involve shorter periods of time than those anticipated for many future space missions. For example, the longest space-simulator studies terminated between 90 and 105 days. "Wintering over" at a polar camp requires, at the outside, a year's commitment, and most studies deal with much shorter periods of time. However, an interplanetary mission will consume the better part of two years. The available data, therefore, may not reflect some important temporal variables.
Third, interplanetary missions, orbiting laboratories, and other space missions will involve a degree of isolation, confinement, and risk rarely equalled by any environment on Earth. Although submarines and Arctic bases may effectively be cut off from civilization by seemingly large distances, such distances are small compared with those that future space travelers can anticipate. The degree of confinement imposed on a space mission may be approximated in a few Earth locations (e.g., in subaquatic dwellings and at polar stations during winter months), and occasionally a very high degree of risk may be found (e.g., in subaquatic dwellings). For the most part, however, Earth environments, by comparison, are tame and hospitable.
Data collected in exotic environments- It is always difficult to conduct good applied research, but the difficulties are multiplied when the research is carried out in an exotic environment. The obstacles exotic environments impose are not insurmountable, but they have handicapped researchers and occasionally forced them to abandon preferred procedures and techniques. To the extent that investigators are forced to eliminate control conditions, to use gross rather than refined measurements, or to rely on impressions and memories, there is increased latitude for error in their observations.
It has often proved difficult for an investigator to be present when a group is undergoing conditions of isolation, confinement, and risk. There may be severe constraints on the number of people who  can participate, and inquisitive individuals who are not essential to getting the primary job done may have to be left behind. As a result, some researchers have been forced to rely on data gathered before and after the mission. Researchers who do accompany a mission may find it difficult to build the necessary rapport with the other members of the expedition. Unless a researcher is making some very clear contributions to group welfare (e.g., by serving as a cook), he or she may be seen as a drain on the group's resources and become a target for resentment. In addition, certain research activities, particularly those examining the relationship among members, may threaten the stability of the group.
In some remote environments, electronic surveillance can be used instead of participant observation. The underwater-habitat research shows that devices such as video monitors can be put to good use (Radloff and Helmreich, 1968). However, the same research shows that electronic surveillance has certain limitations. Much of the activity may take place out of the range of the surveillance gear and the quality of signals may be poor. Such gear may have to be installed in inaccessible locations, making it difficult to adjust or repair. In some remote environments, electronic surveillance equipment may be inadmissible because of space and weight restrictions.
Reviewing the literature, one cannot help but be impressed by the ingenuity, and frequently the bravery, of the researchers who have ventured into the realm of exotic environments. Nonetheless, it is important to remember that not all of the barriers to good research have been overcome successfully, and the results of such studies must be interpreted with these limitations in mind.