In most organizations there is neither the opportunity, nor the need, nor the desire to interact with all other members. Functional communication networks describe the patterns of communication which evolve among individuals or nodes (i.e., who talks with whom). The unit of analysis in communication networks is not the individual, but rather the relationship between or among individuals (Rogers and Agarwala-Rogers, 1976). The methodological techniques used to study communication networks include traffic monitoring, studies of task requirements, participant-observation of interactions, cross-sectional surveys, small-world procedures (taking one part as representative of the whole), and studies of message diffusion. The uses to be examined by these methods are production (getting the job done), innovation (exploring new options), and maintenance (keeping the system and its components operational). In this section we consider how studies of communications networks can help us to  understand information flow within a space organization and between the space organization and external systems.
Information may flow in several directions within an organizational structure. Communication flowing in different directions serves different functions and is likely to encounter different obstacles or barriers.
Formal communication networks- Formal communication networks reflect management-imposed structures which channel interaction up and down the organizational line and, to a lesser extent, laterally among peers. Formal communication networks are highly important to the management function, and managers spend an average of 75% of their time in communication activities (Bair, 1980). Communication from managers to subordinates typically assumes one of five types (Katz and Kahn, 1978): (1) inculcation of organizational or group goals, (2) explanation of organizational policies and procedures, (3) job rationale, (4) job instruction, and (5) feedback. As Katz and Kahn note, although a manager's task may be simplified by offering subordinates only job instruction and feedback, more general instruction gives workers a framework for coping with nonroutine conditions and promotes identification with organizational goals. Therefore, the first task of a space manager is to identify and impart the goals of the organization or mission.
Once a communication framework has been established, attention can be turned to using that framework to meet organizational needs. Communication up the line helps managers monitor performance and provides information that is useful for making decisions. Communication down the line provides direction, course changes, and feedback. Although downward communication can be direct, as when top management issues an edict to subordinates at all levels, certain conditions serve as barriers to the upward flow of communication First, role expectations cast subordinates as listeners rather than as communicators. Second, since managers control their subordinates' fates, subordinates tend to censor communications which might displease the manager or cast aspersions upon their own performance Third, upward communication tends to proceed in a step-by-step fashion. At each step, someone is in a position to act as a gatekeeper. Although this individual may perform the positive function of preventing information overload, he or she may also filter, distort, or block needed information. In a steep, multilevel  hierarchy, it is unlikely that messages from the lowest levels will ever reach the top. Space planners and managers must be aware of these barriers and establish mechanisms to smooth the upward flow of important information.
Horizontal or lateral communication involves the exchange of information among workers at the same hierarchical Ievel. As Katz and Kahn (1978) note, horizontal communication eases some of the burdens of management because peers can indoctrinate and train one another, and can coordinate activities of groups of workers. Moreover, horizontal communication provides important and necessary socioemotional rewards. However, peer indoctrination and training can be faulty or even at cross-purposes to management goals. Some organizations adopt heavy- handed managerial techniques in order to discourage horizontal communication flow. However, this form of cure may be worse than the ailment, particularly under conditions of isolation and confinement. In space as elsewhere, the problem is not one of preventing horizontal communication, but of preventing such communication from assuming destructive forms.
Informal communication networks- In addition to the imposed organizational arrangement, group members construct their own communication networks. These informal networks have two basic purposes. The first function of an informal network is to compensate for inadequacies in the formal network by establishing new links to bypass obstacles that emerge in the formal structure. In many groups there is someone who can expedite the matter at hand; frequently, the expeditor is not the person charged with the responsibility. By locating the right person (who may be anyone in the organization), the informal network is used to serve organizational goals.
A second function of an informal communication network is to serve the needs of the individuals involved, whether or not these needs coincide with the goals of the organization. These informal networks link those with similar interests and experiences (Rogers and Kincaid, 1981) and those who simply like each other.
Informal networks serve a valuable organizational function: they protect the individual from becoming isolated from colleagues of his or her profession by stimulating him or her to more creative thinking and by supplying a psychological support group. It is not unusual for an ongoing, informal work relationship to obscure the formal organizational structure until, finally, the formal is forgotten. Within large spacecrews, we can expect that informal networks will  arise. In examining the advantages or problems of an organizational unit, informal communication networks must be considered as carefully as formal communication networks.
Group membership- Different organizational subsystems can constitute themselves into cliques or factions which do not communicate effectively with one another. Members of particular groups may have difficulty identifying or appreciating each others' specific perspectives and goals. The attitudes and behaviors of most subgroups or cliques are strongly influenced by one or a few individuals called opinion leaders. It is important to know who is likely to emerge as an opinion leader in space, and how this individual's influence on other clique members can be directed toward positive and productive interactions with other subgroups. Likert (1961) has suggested that good communication and cordial relations can be promoted among different groups by having selected individuals maintain simultaneous membership in them. A person serving this "linking pin" function is likely to understand the needs and views of each group and to be able to represent each to the other. From previous confinement activity, we know that participation in two or more subgroups improves intergroup relations. In the Tektite underwater research project, benefits accrued from having engineers and scientist-aquanauts play active roles in each others' fields of expertise (George Washington U., 1974). The linking-pin function differs from the boundary-role or bridging function described in chapter VIII in that the former requires membership in several groups, whereas the latter involves holding a membership in only one group while acting as a point of contact for the other. A third role is that of the liaison, where the individual connects two or more cliques within a system without belonging to any (Rogers and Agarwala-Rogers, 1976). These roles share many of the same requirements. It would be interesting to determine which role accomplishes certain tasks with the greatest effectiveness and with the least burden on the role occupant. It would also be useful to understand more fully the desired characteristics of individuals occupying such roles.
Performance and satisfaction- The structural arrangement of a communication network can influence its effectiveness. Reviews of experimental nets (see, e.g., Shaw, 1976) suggest that when the task is simple and requires people in central positions to collect and distribute messages, centralized nets tend to be an effective arrangement; however, when the task is complex and requires people in  central positions to perform numerous and varied operations, decentralized nets tend to be more effective. In terms of member satisfaction, decentralized nets have been found to offer participants greater feelings of self-determination and to provide more socioemotional gratification than do centralized nets. Conclusions such as these provide valuable insight but are far from conclusive. For instance, the experimental nets examined by Shaw consisted of stations staffed by single unsupported individuals. It is not clear that such findings can be extrapolated to other conditions. Centralized nets could be more effective than decentralized nets even when the task is complex if, for example, the centralized station has higher information-processing capability, as through multiple staffing or data-processing support. In addition, "centralized" and "decentralized" nets are two extreme arrangements. It may be that a preferred system would combine characteristics from each.
To date, spacecrews have been sufficiently small that internal networking considerations have been minimal or nonexistent. However, questions of structuring communication linkages can be expected to grow with the crew and to require more careful analysis in terms of both effectiveness and acceptability.
A fundamental difference between space and other organizational arrangements is that informal contacts between the space vehicle and the ground will be severely curtailed. This limitation puts a large burden on the formal communication network.
For the crew of a space vehicle, external communication will assume one of two forms. These are (1) primarily task-oriented communication with ground control, and (2) primarily socioemotional communication with family and friends.
Communication with ground control- The most important requirements of a communication system relate to effectiveness and reliability. However, given an adequately operating system, communication-related problems can still plague the mission-ground relationship.
As we have seen (chapter 1), isolated and confined individuals tend to direct hostility toward outsiders. A primary challenge, then, is to devise a communication arrangement which provides ground  control with adequate access to the crew, but which does not interfere unduly in the crew's life space. Systems which allow ground control to "tap in" to the crew at will (and particularly systems which tap in unannounced) can be expected to arouse strong negative reactions. First, surveillance itself decreases autonomy and thereby decreases job satisfaction. Research in mundane organizations suggests that people who feel closely supervised tend to be dissatisfied with organizational rules and procedures, downrate their supervisors, and develop hostile attitudes toward management (see Day and Hamblin, 1964). Second, communication systems which allow unannounced eavesdropping or rude interruptions may be seen as an unwarranted infringement on the privacy of the group (see chapter III). Third, communication systems which are under the control of outsiders may raise conflicts concerning who is "in charge." Questions of control or authority can be particularly knotty when the ground believes an issue to be of concern to mission management and the crew believes the issue to be an internal matter.
There is also the problem of who on the ground should have access to the crew. Usually communication from ground personnel is relayed through a third party. (In the case of NASA missions, this responsibility lies with CAPCOM). Yet in a simulation of a Spacelab flight, researchers on the ground found that their ability to collaborate with crewmember experimenters was significantly impaired by this two-step process (Helmreich et al., 1979a). Alternately, if many individuals were to have access to the communication system, the aggregated messages could become overly burdensome and interfere with effective communication. Thus, a major problem confronting planners and managers is to devise a system that provides both ground control and spacecrews with an optimal degree of accessibility to each other. This requirement includes providing the crew with some opportunity for private, internal communication.
The Russian spaceflight experiences have led Gazenko, Myasnikov, loseliani, Kozetenko, and Uskov (1979) to offer two recommendations for aiding the spacecraft/ground-control interaction. First, these authors believe that two-way television communication initiated during the Salyut 6 flight was a definite improvement over earlier one-way video systems, in which only the cosmonauts were viewed. Two-way video provides balance between communicating nodes and also improves the ability of communicators to judge each others' emotional states. Second, Gazenko et al. recommend that radio and other communications operators receive basic training in interpersonal relations. When listening to recent exchanges  between ground control and U.S. missions, it is obvious that ground-control personnel are keenly aware of the role they play in smoothing the interaction with the spacecrew. However, it is not realistic to expect this level of concern to be sustained forever. Training in interpersonal relations could offer an aid to the ground-control/ spacecrew interaction when flights become long and routine.
Communication with family and friends- Personal communication that makes it possible to converse with family and friends has the potential of reducing anxiety concerning events at home and of reducing dependency upon fellow crewmembers for the satisfaction of all interpersonal needs. Extended spaceflight is expected to result in an increased desire to communicate with the folks back home. The Russian experiences have demonstrated that as mission length increases, so do the depth and duration of external communications (Gazenko et al., 1979). Berry (1973a), among others, argues that space voyagers should be given ample opportunity to communicate with people who are important to them personally, and that a scrambler system or comparable device should be used to ensure privacy. However, the value of ready access to people at home is not accepted by all. Some writers argue that it is to the advantage of an isolated and confined group that it remain out of contact with friends and relatives. In support of this position it should be noted that:
1. Certain individuals tend to monopolize communications systems and thereby give rise to conflicts within the group (McGuire and Tolchin, 1961).
2. The failure of someone at home to communicate on schedule provokes worry and fear (Pope and Rogers, 1968).
3. Worriers may remain "glued to the telephone" and neglect other duties (Radloff and Helmreich,1968).
4. The messages received by isolated individuals tend to be bland and unsatisfying (Law, 1960; McGuire and Tolchin, 1961; Earls, 1969).
5. Even otherwise satisfying communications may be followed by a period of letdown or depression (McGuire and Tolchin, 1961).
Communication opportunities undoubtedly bring their share of problems as well as solutions. Observing this issue in space, Gazenko et al. (1979, p. 9) note:
Some of the problems identified above may represent imperfections in the communication systems themselves. For example, the availability of private communication systems may allow for more spirited messages. Or, the failure of a family member or friend to communicate on time may be less worrisome if communication with home is so routine that it no longer is necessary to arrange each transmission well in advance. Post-communication letdown may be minimized if the next opportunity to communicate is in the near rather than in the distant future. Questions of the possible debilitating effects of bad news from home (or alternately of censorship) are also of issue here (see chapter VII).
As discussed earlier in this chapter, a question to be addressed concerns how mediated communication can be used in support of intimate and personal relationships with family and friends. A related question concerns how mediated communication with those at home affects direct relationships within the space vehicle. Mediated communication is generally employed in support of work-related tasks. One would not expect such exchanges to influence face-to-face relationships. In space, mediated communication with family and friends is likely to be emotionally charged and could influence the cohesiveness of the spacecrew. Research on how such communication opportunities could influence primary group relations is needed.
The questions surrounding contact with family and friends at home are among the more complicated interpersonal issues that space planners and space travelers must address. Although our emphasis here is on the spacecrew and their mission, whatever compromises are struck must consider the welfare of those at home as well as those in the space vehicle.