Astronauts on long-duration missions are subjected to many factors that may affect their health, well-being, and performance of mission-related duties. Some of these factors are unique to the space environment (e.g., prolonged periods of microgravity), whereas others are also present in other environments (e.g., confinement, isolation, exposure to physical hazards, altered work or rest schedules). Still others are characteristic of the individuals, groups, and organizations involved in crewed space missions. This chapter discusses the factors that affect behavior and performance during the preflight, in-flight, and postflight phases of manned space missions, and it makes recommendations for research and changes in operations to ensure crew members' safety, well-being, and productivity, along with mission success.1 As such, it is much broader in scope than the study of space human factors, which focuses on the role of humans in complex systems, the design of equipment and facilities for human use, and the development of environments for comfort and safety.2 Although these issues are not addressed here, the committee's objective is nevertheless to provide a comprehensive assessment of the current status and future direction of research in human behavior and performance in space.
Over the past 30 years, a number of reports and publications of scientific panels, working groups, and scientific conferences have identified various requirements for conducting research on human behavior and provided NASA with several recommendations. Those recommendations have been based on a similar set of conclusions as summarized in the 1987 Goldberg report:3
There is not enough objective data to determine the seriousness of behavioral impairments in past spaceflight missions. Nevertheless, there is reason to suppose that pyschological problems have already
occurred in spaceflights and that these will increase in frequency and severity as missions become longer and more complex, as crews become larger and more heterogeneous, and as the dangers of spaceflight become more fully appreciated.
Despite this assessment of the importance of behavioral issues, little progress had been made in transforming the recommendations for research on human behavior and performance in space into action.4 In contrast to the routine collection of data on cardiovascular, neurological, and musculoskeletal changes in-flight since the early days of the U.S. space program, there has been relatively little effort to collect data on behavior and performance in a systematic fashion. Nevertheless, as missions have become longer in duration, issues relating to human behavior and performance have gained increasing prominence. This prominence is reflected in studies of individuals and groups in analogue environments as well as the largely anecdotal accounts of long-duration missions of the Russian space program and the Shuttle-Mir Space Program (SMSP). As could be predicted from controlled simulation studies, 5 6 7 the history of space exploration has seen many instances of reduced energy levels, mood changes, poor interpersonal relations, faulty decision making, and lapses in memory and attention. Although these negative psychological reactions have yet to result in a disaster, this is no justification for ignoring problems that may have disastrous consequences. Furthermore, there are degrees of failure short of disaster and degrees of success short of perfection; if favorable organizational and environmental conditions can increase the level and probability of success, they are worthy of consideration.
Statement of Goals
The 1987 NRC report stated: "The overall goal for the study of human behavior in space is the development of empirically based scientific principles that identify the environmental, individual, group, and organizational requirements for the long-term occupancy of space by humans."8 This goal remains as important today as it was 11 years ago. However, it is important to acknowledge three interrelated elements of this overall goal. The first is the identification of operational requirements for the facilitation and support of optimal individual, group, and organizational performance and the prevention and treatment of performance decrements during long-duration missions. Although priority should be given to the operational relevance of this research, the second element of research on behavior and performance in space is the advancement of fundamental knowledge of human behavior that has relevance beyond long-duration missions. Both of these elements, in turn, are related to a third—promotion of the physical and mental well-being of those directly and indirectly involved in long-duration missions, including flight crews, their families, and their ground support colleagues. All three objectives presume the existence of certain environmental and organizational constraints that will give priority to operational over basic science issues as well as observational over experimental research designs. Nevertheless, the committee acknowledges the importance of utilizing approaches to the study of behavior and performance in space that seek to integrate these diverse sets of issues and designs.
Definition and Assessment of Behavior and Performance in Space
Research in human behavior and performance during long-duration missions is concerned with individual crew members and ground support personnel; groups of individuals who comprise the flight crews and ground support teams of specific missions; and the organizations that recruit, train, and support these individuals. Individual performance has traditionally been assessed using measures of task productivity (ability), emotional health and well-being (stability), and the quality and quantity of
social interactions with other crew members (compatibility).9 10 Group performance has traditionally been assessed using measures of cooperation and conflict.11 12 Organizational performance has traditionally been assessed using measures of the costs and benefits of accomplishing mission, organizational, and overarching national political goals and objectives.
In the past, emphasis has been placed on human behavior and performance research that is conducted in-flight. However, research conducted during the extended period of training and preparation prior to the mission (preflight) and during the aftermath of a crewed mission (postflight) is also viewed as essential in accomplishing the overall scientific goals described above.
Research in Analogue Environments
Much of our understanding of human behavior and performance in space has been obtained from the study of "analogues" such as Antarctic research stations, polar expeditions, nuclear submarines, isolated military outposts and national parks, undersea habitats, oil drilling rigs, small rural communities, and space simulator experiments.13 14 15 16 These analogues serve as "model systems" of behavior in space in much the same way that hindlimb unloading and bed-rest studies described elsewhere in this report serve as model systems of physiological changes related to microgravity. In many instances, a considerable amount of data that are relevant to long-duration space missions has already been collected. These data sets also offer a larger sample size than is typically available from either the U.S. or the Russian space programs. The collection of new data in analogue environments may also be cheaper than collecting similar data in space for logistical reasons. Thus, analogue studies are more cost-effective than new research conducted in space and provide an opportunity to identify and resolve problems on the ground before they occur in space. Simulator studies can be especially useful, since they lead to the characterization of important space-related psychosocial factors under controlled conditions, expose possible relationships between these factors, and allow variables to be manipulated in a systematic fashion.
However, analogue settings vary with respect to their relevance to long-duration space missions.17 Such missions and each of the analogue environments exhibit important differences with respect to characteristics of crew members, procedures for screening and selection, crew size, mission objectives and duration, and the nature of the physical environment. Patterns of behavior associated with adapting to the extreme cold and extended periods of darkness during the Antarctic winter, for instance, may be very different from patterns of behavior associated with adapting to the microgravity environment of space capsules. Similarly, lessons learned about the effects of duration of exposure to isolation and confinement from studies of submarine crews may not be relevant to astronaut crews that are much smaller in size. In general, analogue studies are believed to be necessary and suitable for examining many of the issues described in this chapter, including: environmental conditions common to isolated and confined environments, circadian rhythms and sleep, the psychophysiology of emotion and stress, stress and coping, cognition and perception, emotion, personality, crew tension and conflict, crew cohesion, ground-crew interaction, leadership, psychosocial countermeasures, organizational culture, mission duration, and mission management. Other issues can be examined only under actual conditions of spaceflight. These include the effects of microgravity and the absence of a normal diurnal cycle on sleep and circadian rhythms, cognition and perception, affect and the hypothalamic-pituitary-adrenal axis; psychopharmacology; and the requirements for conducting valid and reliable psychophysiological measures in space. There is a need to determine how to connect data collected in analogue settings to the characteristics of the space program. In addition, greater emphasis is required on determining how knowledge obtained from analogue environments can be incorporated into the National Aeronautics and
Space Administration (NASA) activities with respect to the screening and selection of astronaut personnel, development and implementation of training programs and psychological countermeasures, and development and testing of data collection procedures that meet the requirements listed above.
Integration of Research and Operations
Research on behavior and performance in space presents numerous opportunities to integrate the goals and objectives of researchers and operations managers and to simultaneously address issues of theoretical and operational importance. There is a need to bring researchers, clinicians, and managers involved in operations together to identify and prioritize the needs for research from the operational perspective and the resources available to conduct behavior and performance research. There is also a need to conduct research that demonstrates a relationship between issues with operational relevance and the more fundamental questions related to human behavior and performance in general. For instance, research conducted on a long-duration mission or in analogue environments offers the potential for determining the extent to which various personality characteristics such as neuroticism, extraversion, and openness influence cognitive performance, patterns of stress and coping, social dynamics, or measures of health and well-being. Similarly, the extent to which crew member autonomy or control over workload influences health, well-being, and performance could provide greater insight into the role of self-efficacy and personal autonomy in general.18 Ultimately, research on behavior and performance in long-duration space missions that meets the needs of the larger society, as well as the more specific programmatic needs of NASA and other space agencies, should be designed and developed.
Organizational Support of Research
Research on human behavior and performance in space requires first the development of an organizational climate that is supportive of such research. The principal task in creating such a climate is providing access to the objects of study (i.e., space crews and ground control personnel). Previous NRC recommendations and other reviews of the need for research on behavior and performance in space have emphasized the importance of gaining access to those involved in crewed space missions.19 In the past, there has been a great reluctance on the part of the astronaut community to participate in such research because of concerns over the lack of confidentiality and the potential for inappropriate use of information that could-threaten assignments to specific missions and jeopardize careers. Even if astronauts are willing to participate in such research, they are unlikely to be in a position to provide information on behavior and performance if they operate in an organizational environment that does not support the collection and analysis of such information and that provides no safeguards against its misuse. The ability to convince the individuals, groups, and organizations who are the objects of this research to participate is critical to its success. However, access implies some form of reciprocity between behavioral scientists and their subjects. Although previous reports have implied that it is the primary responsibility of NASA to provide access to study subjects, behavioral scientists must share responsibility in this regard. This responsibility includes clear explanation of the importance of such research, demonstration of its relevance to mission operations, and implementation of procedures that will ensure the confidentiality of data collected and prevent the misuse of these data. It may also be worth considering an alternative strategy in which researchers and study participants collaborate in refining the design and execution of studies that are of interest and importance to both parties. This kind of "action research" in operational settings often can generate more trustworthy findings (and therefore better science) than studies using methods that have been optimized for laboratory conditions. Moreover, a more collaborative
approach can often avoid the "us-versus-them" dynamic that not infrequently develops between researchers who need compliance with their procedures and subjects who understandably may object to invasive questions, instruments, or protocols for research whose purpose is not fully understood or for which they view themselves merely as objects under study.
Research in behavior and performance also requires an increase in the level of institutional support for psychologists, psychiatrists, and other behavioral scientists within the respective organizations involved in long-duration missions. Such support may take several different forms—from increased funding for NASA scientists to interact with colleagues at professional meetings and conferences, to a greater role in management decision making. Increased visibility of the behavioral sciences within the management framework of NASA would contribute substantially to creating a climate that is favorable to research in behavior and performance.
A third requirement is a commitment to ongoing data collection for operational and research purposes. As with any data collection activity, it is much easier and more cost-effective to maintain an ongoing data collection system than to intermittently initiate and discontinue data collection efforts.
A fourth requirement for the organizational support of research in human behavior and performance in space is improvement of the peer review process for grant proposals and expansion of opportunities for the dissemination of study results to the wider research community. At present, proposals for research in behavior and performance are reviewed by panels that are composed almost exclusively of investigators with expertise in space human factors, with almost no input from investigators with expertise in the social and behavioral sciences. In contrast to the recommendations of the Committee on Advanced Technology for Human Support in Space (1997),20 this committee believes that NASA should continue to separate behavior and performance from space human factors at the managerial level. Although there are admittedly certain advantages to the integration of management efforts in these two interrelated areas, one of the problems with conducting behavior and performance research in the past has been the low priority accorded to such research in favor of work conducted in areas such as ergonomics, biomechanics, anthropometrics, and workload. In part, this low priority has been the result of failure to understand the different focus of behavior and performance research and space human factors research. Greater efforts are required on the part of NASA to identify and recruit experts in human behavior and performance in space and analogue environments, as well as experts in disciplines that have relevance to the issues described below, to participate in such research, review grant proposals, and evaluate study findings. Greater efforts are also required on the part of investigators to publish many of the results that currently exist only in anecdotal form, abstracts of conference proceedings, or the "gray" literature of technical reports.
Living in a small capsule for a prolonged period exposes the group to chronic, cumulative stress from a variety of environmental sources. This is an increasingly serious issue as missions become longer, because stressors and vulnerability to stress accumulate over time. 21 Stress effects are also exacerbated by unexpected reductions in living space, habitability, or safety, which may become even more serious as missions involve longer duration and lower accessibility.
Environmental Conditions Unique to Spaceflight
As described in Chapter 5, microgravity significantly disrupts such basic aspects of perception and behavior as vertical orientation and energy expenditure, and is causally linked to space motion sickness.
Microgravity has important implications for ergonomic design, and its possible effects on task performance, visual orientation, and emotional well-being during long-duration missions clearly require intensive research. Prolonged periods in small enclosed spaces, combined with microgravity, have effects on perception and motor behavior. 22 A recent report that astronauts cannot accurately recall the position of an unseen target has implications for safe manipulation of controls when visual contact is lost.23 As noted in Chapter 5, depth perception, eye-hand coordination, and visual constancies may also be affected during flight. Systematic in-flight research on how design features might remedy these problems (e.g., by establishing a consistent local vertical)24 is needed.
A host of minor discomforts peculiar to spaceflight may add up to the most stressful aspects of capsule life. Such chronic stressors or "daily hassles" include uncomfortable levels of temperature and humidity, limited light (to conserve power), noise and vibration from machinery, constant vigilance involved in monitoring instruments, the need to put on and take off clumsy protective clothing for every venture outside the capsule, the growing accumulation of garbage and floating particles, and limited facilities for sanitation and refreshment. Environmental pollution, in particular, may have different emotional and performance effects on different individuals, and tolerance for such conditions may be worth testing as an aspect of astronaut selection and training. Environmental pollution may also cause olfactory distress, and although psychological adaptation and physiological habituation to unpleasant olfactory stimuli have been studied, they have not been investigated during prolonged capsule living. Analogue studies typically have not involved the deliberate induction of discomfort, but future studies should do so because such conditions are very likely to have emotional consequences that would affect individual performance and group dynamics.
Some unique environmental features are not only unpleasant but also dangerous. A good example is the degradation of the internal atmosphere through increased carbon dioxide levels or through fuel or gas leaks. For example, glycol was released into the atmosphere on board Mir in April 1997; the crew had to don protective gear for extended periods of time, which further increased discomfort and inconvenience. These and other potential dangers, such as radiation and loss of pressure, make spaceflight intrinsically stressful. It is important to establish how space crews assess and react to the continuous possibility and occasional occurrence of hazards and whether these processes differ in short-duration and long-duration missions. There is a critical need to examine the perceived likelihood and severity of risk factors, how the perceived risk influences the individual and group performance of the crew, and what countermeasures would minimize their fears.
Environmental Conditions Common to Isolated, Confined Environments
Space vehicles are part of the class of isolated, confined environments (ICEs) that have a number of shared characteristics. Some of these pose a challenge for the crew and therefore must be considered in physical and behavioral design processes. For instance, several ICE stressors are related to physical and social density: crowded, minimally partitioned spaces violate the fundamental need to maintain control over other people's access to oneself. In normal environments, this control is exercised by means of interpersonal distance, territoriality, and privacy. When control over these factors is eroded, stress results. 25 Violations of interpersonal distance, territoriality, and privacy are common in ICEs and can result in irritability, tension, personal conflicts, withdrawal, and performance decrements (especially in tasks that require cooperation). These problems may be exacerbated when the crew simultaneously has to cope with other demands, when cohesion is already low, or when the group includes people from cultures that follow different norms. For instance, preferred interpersonal distances are greater in North America and Western Europe than in the Middle East and some parts of Asia and Latin America, and a
distance that appears comfortable to one participant in a cross-cultural interaction may signal aggression or rejection to the other.26
Research is needed to understand how stressors associated with the physical and social density of ICEs are likely to be affected by the unique characteristics of spaceflight (e.g., the peculiarity of microgravity makes possible some new and strange interaction orientations) 27 and how they influence specific aspects of performance and adjustment in missions of various types and durations. Space simulators could be used to assess how interior design (e.g., movable bulkheads; improved sound insulation; curtains around sanitary facilities; seats that can be arranged to promote or discourage social, visual, and auditory interaction) can optimize privacy, interpersonal distance, and territoriality within the limitations of the vehicle's payload and construction. Research should also be devoted to the development and evaluation of training programs and other countermeasures that promote individual privacy and territoriality and interpersonal distance. Particular attention should be devoted to the development and evaluation of programs that provide instruction on individual and cultural differences in the need for distance, privacy, and territory and efforts to maintain them.
Monotony is another characteristic of isolated and confined environments that will likely influence behavior and performance on long-duration spaceflights. Previous research in analogue settings indicates that the lack of variation in the physical and social environment can result in boredom, loss of energy and concentration, and interpersonal friction. Because it is difficult to change the environment, perception of reduced control may also occur, a situation that is very disturbing to individuals such as astronauts who view themselves as effective agents in controlling their own lives.28 However, additional research is required to determine whether physical monotony intensifies the desire to explore and manipulate elements of the environment during long-duration missions and the conditions under which the desire to test one's abilities can result in the manufacturing of artificial challenges, sometimes by taking unnecessary risks and ignoring familiar safety rules.29
Research on the effects of physical monotony can also contribute to the development of effective countermeasures. This might include, for instance, the design of activities that offer challenge and perhaps excitement without jeopardizing the crew or the mission. "Surprises" could be delivered by resupply flights, or the capsule itself (e.g., on a Mars voyage) might carry research or other tasks, music, reading matter, videotapes, family packages, and so on, to be opened at different points along the mission. The efficacy of such countermeasures should be evaluated in analogue studies before the policy is implemented.
There is also a need to develop and evaluate countermeasures that maximize the crew's control over the environment.30 Nonstandard items of clothing, food, recreational materials, and reminders of home are already in use (although their effect has not been systematically studied); in addition it might be possible to let astronauts change color schemes within the capsule (perhaps through projection31), move some pieces of furniture or equipment, and attach items of personal significance or pleasure to the interior. News from and communication with home, and stimulating multimedia resources, can relieve the unchanging ambient stimulus array.32 Natural images—projected scenes, audiotapes, released odors33—might be especially useful, and windows have been found to relieve visual monotony and maintain a sense of contact with Earth.34 We need to study what happens when the view from the window is essentially unchanging and when Earth is not visible. In such cases, the window may become a source of more boredom, and both it and the natural scenes can become sources of loneliness.
Long stretches of monotonous unstructured time are likely to be a problem on long-duration missions. Crew members in such environments (e.g., polar crews,35 prisoners in solitary confinement36) can suffer from too much free time. When the team spends many months or years in the environment, leisure periods can become a time of boredom, lassitude, neglected hygiene, and apathy.37 Research is
necessary to develop countermeasures for this problem, such as systematic programs of some sort, whether fitness exercises, study, or hobbies. Group activities of the same sort can also be developed.
Research on environmental factors should include an examination of the following topics, listed in order of priority:
- The effects of the physical and psychosocial environment of spacecraft on cognitive, psychophysiological, and affective measures of behavior and performance:
- Affective and cognitive responses to microgravity-related changes in perceptual and physiological systems;
- Behavioral responses to perceived risks associated with the space environment (e.g., radiation, contamination of the ambient atmosphere, buildup of debris, use of breathing apparatus and space suits); and
- Psychosocial predictors of the use and perceived importance of "personal" territories and individual strategies for coping with physical and social monotony.
- The development and evaluation of countermeasures for mitigating adverse effects of the physical and social environments on individual and group performance:
- Alternative methods for filling unstructured time such as organized group and individual recreation and leisure activities;
- Use of novelty or "surprises" in terms of work assignments, recreational materials, and messages/gifts from home to reduce boredom and monotony;
- Crew training in communication and acceptance of different levels of desired privacy, interpersonal distance, territoriality, and personal disclosure; and
- Design of spacecraft interiors and amenities to maximize control over the physical environment and reduce impacts of physical monotony on behavior and performance.
Circadian Rhythms and Sleep
Sleep is a basic human need that normally occurs in a temporally regular pattern, beginning at night and ceasing with the day. Alteration or disruption of this normal circadian pattern affects sleep duration and may induce a sleep deficit. Lack of sleep contributes to stress and to inefficiency in cognitive and psychomotor performance. Poor sleep and fatigue have been reported on a number of short-duration Shuttle missions as well as long-duration Mir missions. About 30 percent of U.S. Shuttle astronauts have requested sleep medication in-flight, although none had a history of such usage on Earth.38
Under natural conditions, the sleep-wake cycle and other circadian rhythms are synchronized with the period of Earth's rotation by means of periodic factors in Earth's environment. The most important of these zeitgebers are day-night changes in light and temperature.39 Current plans for the International Space Station call for illumination levels ranging from 108 to 538 lux. This is much lower than the 2,500 lux necessary to entrain circadian rhythms in humans.40 Hence, some desynchronization of sleep-wake and other circadian cycles would be expected to occur.
There are wide individual performance differences that are dictated by circadian rhythm patterns, ranging from those whose optimal work physiology peaks early in the day to those who can work
efficiently long into the night. These patterns are consistent and are likely to persist in the space environment despite the imposition of a common work schedule. On the other hand, groups in temporal isolation have been found to display synchronous circadian rhythms. 41 42 Research is needed to determine whether it is important to match work groups in circadian pattern for greater crew harmony or whether, perhaps, different types should be distributed in a crew so that someone is always at optimal physiological efficiency.
Sleep deprivation has also been commonly reported by personnel working in other ICEs. However, research is required to identify the consequences of sleep disruption. For instance, the inability to concentrate, intellectual inertia, an increase in suggestibility and hypnotizability, and sensory hallucinations reported in laboratory and antarctic studies 43 may be a consequence of sleep disruption or of reduced social and environmental stimulation and increased monotony. Studies of night-shift workers and individuals in temporal isolation have found sleep disruptions to be associated with significant decrements in cognitive performance and increases in tension, depression, anger, and confusion.44 45 A number of theories have been proposed to explain the association between sleep, cognitive performance, and mood, including the phase-advance or phase-shift hypothesis (which postulates that during depression the strong circadian X oscillator—which governs core body temperature, rapid eye movement, sleep propensity, and plasma cortisol secretion—is advanced in its timing relative to the weaker Y oscillator, which modulates the rest-activity cycle, propensity for slow-wave sleep, and plasma growth hormone levels),46 the circadian dysregulation or attenuation hypothesis (which postulates that circadian rhythms in depression are characterized by a loss of power or rhymicity), 47 and the entrainment error hypothesis (which postulates that depression is the result of a lack of temporal stability in the circadian cycle resulting from weakened entrainment to the 24-hour day).48 However, the conditions under which sleep affects or is affected by mood and cognition during a long-duration mission remain to be identified. Studies conducted in-flight, along with ground-based simulations of long-duration missions, offer a unique opportunity to examine the merits of these competing theories and to determine how different circadian systems mediate the association between sleep and performance or well-being. Similarly, research is required to determine whether changes in sleep that occur during long-duration missions are a function of stress, workload, isolation, confinement, the absence of social zeitgebers or other environmental cues (e.g., a 24-hour day-night cycle) that influence circadian rhythms, or other features of the physical environment (microgravity, noise, light, atmosphere).
Another issue that should be investigated in the next decade is whether members of space crews experience improved sleep when they are allowed to set their own work-rest schedules or when they are required to adhere to a fixed schedule. During the Soyuz program, when sleep schedules were set counter to the local time of the launch site, cosmonauts experienced some degradation of performance and disturbed sleep.49 Early research under conditions of isolation revealed that human circadian rhythms tend to "free-run" for a period of approximately 25 hours.50 However, further research is required to determine the probability of major dissociations and desynchronizations in circadian systems under uniform or individualized work schedules in an isolated and confined environment and the long-term consequences of such desynchronizations. The environment used in most ground-based research is contrived, work activities set for subjects are often purposeless, and the experimental designs invariably involve solitary confinement without knowledge of time.51 Evidence from analogue settings as to the costs and benefits of allowing personnel to "free-cycle"and set their own schedule versus maintaining a fixed work-rest schedule remains inconclusive.52 53 54
A third issue related to sleep during long-duration missions concerns the long-term effects of sleep deprivation. Evidence from the Antarctic suggests that the restoration of normal sleep patterns, especially Stage IV sleep, may take as long as 2 years for individuals in an isolated and confined environment.55
Similarly, laboratory studies suggest that individuals may unknowingly accumulate very large sleep debts with an associated vulnerability to a decline in performance during periods of monotony and reduced stimulation.56 However, the extent to which differences in individual characteristics (e.g., age, gender, levels of stress, coping styles, personality) or environmental context (e.g., workload, light-darkness, noise) are associated with such accumulation has yet to be determined.
The Psychophysiology of Emotion and Stress
The data on human emotional reactions involve three primary response systems: (1) language responses, including reports of feelings, evaluative judgments, and expressive communications; (2) behavioral acts such as avoidance, attack, and performance deficits; and (3) alterations of the sympathetic-adrenal-medullary (SAM) system and the hypothalamic-pituitary-adrenal (HPA) axis. These different outputs have unique sensitivities and temporal parameters and can be separately shaped by the environment. Cross-correlations between systems are often low, and a single channel of information one emotion may grossly mislead. It is not uncommon for some individuals, reporting no fear or anxiety when under palpable stress, to nevertheless show marked, sustained sympathetic activation of the HPA axis. In this context, the physiological marker may be the better predictor of future behavioral disturbances and performance inefficiency.
Furthermore, it is important to consider that the psychological meaning of physiological changes is not obvious or always consistent with common assumptions. For example, heart rate (a measure often taken during spaceflight) decreases (not increases) when organisms orient to threatening stimuli. Physiological data must always be interpreted in the context of their collection, with reference to focal stimuli, tasks being performed, social and physical environment, and related verbal and behavioral responses. Understanding the emotional significance of physiological data depends on careful research in the applied settings of interest.
Research on the psychophysiology of stress and emotion in the general population suggests that the alterations in the HPA axis likely to occur during long-duration missions, as described in Chapter 9, may also have significant impacts on mood and memory.57 However, the precise nature of these mechanisms and the extent to which they affect other aspects of performance, including cognition, emotion, and social interactions, remain to be determined. For instance, relatively pronounced HPA activation is common in depression, but it is unclear whether HPA activation causes or results from depressed affect. Studies in-flight will be required to identify the cognitive and affective correlates of hormonal, cardiovascular, respiratory, and other physiological changes that represent alterations of the HPA axis and the direction of causality of such associations.
Considerable research has been conducted on the use of flight simulators for training and evaluation,58 but there is a dearth of psychophysiological data from this setting. It has been shown that media representations and simulated stress situations involving anger, fear, or anxiety generate physiological patterns of response similar to those occasioned in the actual context.59 This suggests that much could be learned from psychophysiological studies of simulated stressful missions that might then be used in the development of effective countermeasures. For example, does the crew's preflight physiological state predict the probability of crew conflict, social interaction problems, and poor performance? Are there physiological markers during the mission that augur reduction in crew efficiency (error proneness, inattention, etc.) that could prompt early preventive remediation?
Most psychophysiological research uses average responses of many subjects and many trials with the same stimulus event within the experimental session to isolate weak but important signals in naturally noisy biological systems. Although this technique is suitable for defining general psychological
principles, it is less useful in telling us about persisting individual characteristics. Lacey observed that physiological stress response patterns differ among individuals.60 That is, one subject's arousal reaction may involve strong cardiac rate increases, whereas the cardiovascular reaction of another subject may be more strongly reflected in blood pressure. Similarly, some subjects show clear changes in sudomotor systems in response to any stimulus input; for others, the skin conductance response may be totally absent. These idiosyncratic patterns, particularly their stability over time, have not received extensive study with modern methods of measurement and analysis. Where the performance of specific crew members is the concern, the understanding of these unique signatures is a key goal.
To fill in this data gap, we need more studies that look at the organization and stability of response patterns in individuals over periods of weeks or months. It is particularly important to evaluate physiological patterns that are reactions to defined, repeatable stressors (e.g., physical threat, social stress) and to meaningful tasks. Problem features of the space environment will need to be included in the stimulus array being tested (e.g., confined environment, small-crew interactions). Eventually, these experiments should be conducted in space so that the physiological effects of microgravity can be made part of the equation.
As detailed in Chapters 5 and 8, weightlessness involves gross changes in cardiovascular and neurological functioning. Many crew members report that these physiological events are highly unpleasant, and they show related, significant performance deficits. An effort should be made to assess individual differences in reactions to these physical stressors prior to the actual experience of space. Stern and colleagues, for example, have investigated reactions to bodily rotation and the reactions of a stationary subject within a rotating optokinetic drum (which fills the visual field).61 The latter produces symptoms of motion sickness like those found in space. The electrogastrogram—a noninvasive method for measuring changes in stomach and intestinal motility—can be used to measure smaller and anticipatory autonomic nervous system (ANS) reactions that predict more severe motion sickness. It is important to study parallels in cardiovascular and psychomotor patterns and to see if there are common characteristics of emotional temperament that correlate with this form of distress.62 The effectiveness of biofeedback and other behavioral coping strategies in reducing these patterns and their effect on performance should also be explored.
Psychophysiological Measurement in Space
Psychophysiological measurement is most meaningful in the context of a clearly defined stimulus and a focused task demand. For the busy astronaut, mission projects need to be analyzed to identify natural assessment tasks. This might be instrument monitoring or motor control requirements embedded in regular maintenance activities, or in recreational interactions with the computer (e.g., competitive games), by individuals or groups.
The following measures are potentially sensitive to psychological stress, mood, motivation, and attention.63 The current technology is adaptable for use outside the laboratory. However, a continuous effort should be made to develop instrumentation that is more portable, nonintrusive and natural on the body, and robust in the space environment. This is an important engineering goal that NASA should support.
- Heart rate and variability, electrocardiograph (EKG) waveform, pulse volume. Heart rate tends to decrease in characteristic ways with attention to external stimuli. Heart rate changes are also associated with emotional reactivity, being modulated differently by affective valence and motivational intensity. Spectral analyses of interbeat interval distributions permit an estimation of vagal tone and autonomic
- nomic balance (sympathetic versus parasympathetic) that may help predict stress vulnerability. Sympathetic cardiac control varies with t-wave amplitude, providing a collateral estimate of ANS arousal.
- Facial muscle action. Facial expression defines emotion for some theorists. Formal coding of facial changes is done in social psychological studies of emotion, but it is slow and labor intensive. The development of computer analytic methods for on-line measurement of facial expression from video observation is an important goal for instrumentation development. This could be used in conjunction with voice frequency analysis (employed in the Russian space program) to provide a powerful, unobtrusive method for assessing emotional interactions. Facial muscle action potentials can also be monitored directly. This has the advantage of providing data on expressions that are below the threshold of visual detection, but has the disadvantage of requiring that electrodes be placed on the face, with a resulting intrusiveness of measurement.
- Blink rate and blink magnitude (probe induced). Blink rates vary with attention and anxiety, and can be monitored by simple electrodes, strain gauges, or high-speed cameras. Furthermore, brief acoustic probes (e.g., 50 ms, 90-decibel noise) can be presented, prompting mild reflexive blink-startle reactions. During perception, the magnitude of such noise-induced blinks has been shown to reflect emotional state—larger startle during unpleasant states and smaller in pleasant states.
- Temperature (ear canal and skin surface) measurement. Facial temperature varies with emotional reactivity. Tonic changes in temperature are valuable in assessing circadian rhythms.
- Electroencephalograph (EEG). The EEG is particularly useful in evaluating sleep patterns and in assessing attention and arousal. Currently, the simultaneous measurement of up to 128 electrode sites is practical.
In recent years, a variety of neural imaging methods have been developed that add significantly to the psychophysiologist's armamentarium. For example, as noted in Chapter 5, magnetic resonance imaging (MRI) can be used to acquire a detailed picture of the living brain in which individual structures are readily discerned. Furthermore, by relying on the detection of changes in the brain's regional blood flow, the functional activity of specific brain areas can be imaged as subjects perform cognitive tasks or are exposed to emotional stimuli. Although these methodologies cannot be taken into space, they can be used before and after a flight and thus allow evaluation of changes in brain structure and function that could result from extended stress, isolation, confinement, and microgravity. One might speculate, for example, that the reported impairment of short-term memory in some crew members64 might be secondary to actual changes in the hippocampus. In conjunction with its use to assess changes in cortical maps associated with changes in sensorimotor integration, as described in Chapter 5, MRI would provide a method to assess these and similar questions about changes in the brain that may be attendant on prolonged exposure to the unique physical and psychosocial stressors of long-duration space missions.
Research on psychophysiological factors of behavior and performance during long-duration missions should include an examination of the following issues in order of priority:
- In-flight studies of the characteristics of sleep during long-duration missions, including predictors of change in sleep quality and quantity; whether sleep deprivation is cumulative; how much sleep debt is necessary to produce an overall impairment of cognitive performance, mood, and interpersonal behavior; and whether reductions in sleep debt are associated with improved performance;
- Ground-based studies of change and stability in individual physiological patterns (e.g., cardiovascular, neuroendocrine, and immune system changes related to alterations in the hypothalamic-pituitary-adrenal
- axis) in response to psychosocial and environmental stress and their applicability to measures of behavior and performance in-flight; and
- Development of psychophysiological instrumentation that is highly portable, nonintrusive, and robust in the space environment.
Stress and Coping
Cumulative stress has certain reliable effects, including psychophysiological changes related to alterations in the sympathetic-adrenal-medullary system and the hypothalamic-pituitary-adrenal axis (hormonal secretions, muscle tension, heart and respiration rate, gastrointestinal symptoms), subjective discomfort (anxiety; depression; changes in sleeping, eating, and hygiene), interpersonal friction, and impairment of sustained cognitive functioning. The person's appraisal of a feature of the environment as stressful and the extent to which he or she can cope with it are often more important than the objective characteristics of the threat.65 Several behavioral and psychophysiological measures of responses to various major and minor stressors have been identified and used in studies of the general population. However, as noted in the preceding discussion of psychophysiological issues, more information is needed on the relationship between self-perceived, performance-related, and physiological signs of stress within a highly selected and motivated group such as space crews because these measures do not consistently correlate with one another. Use of these behavioral and physiological measures to assess the efficacy of coping responses should be examined critically for the same reasons.
Given that spaceflight is intrinsically and perhaps chronically stressful, coping is a crucial area of research. Selye's model of the General Adaptation Syndrome, widely accepted as the basic description of the stress and coping process, indicates that as a stressor appears and continues, the individual's coping resources are first mobilized (the alarm stage), then deployed (resistance), and eventually, if the situation is not resolved, depleted (exhaustion).66 Among highly competent and self-confident people such as space crews, resistance is likely to be effective and last a long time. However, prolonged severe stress or the impact of several simultaneous stressors will eventually reduce the coping resources of even the strongest organisms. Where one stage ends and the next begins—especially the threshold between resistance and exhaustion—can be crucial to the success of a mission and the survival of the crew, and both behavioral and physiological markers of the stage transition must be established through studies that compare baseline and follow-up measures of these stress responses with mission duration, workload, changes in the physical and social environment (e.g., increase in environmental pollutants, interpersonal tension), and scheduled and unscheduled events.
The specific coping strategies of spacefarers should also be studied. Research has identified two major categories of strategies, problem oriented and emotion oriented.67 The former include methods for solving or avoiding a problem; the latter are appropriate when neither a solution nor escape is feasible, and the only available strategy is to try to endure the situation. The selection of one or both types of coping strategies in responding to a specific stressor depends, in part, on the characteristics of both the stressor and the individual. Differences in demands placed on the individual by the physical and social environment and the organization of the mission may require different coping strategies. An understanding of what coping strategies are employed under what situations is critical to the development
of effective countermeasures designed to support effective coping responses to the chronic and acute stressors likely to occur during long-duration missions.
Although inter- and intrapersonal problems arising from environmental stressors may occur during long missions, measures of both positive and negative reactions are needed for a complete picture of what one may expect from an extended mission. Understanding and predicting beneficial and enjoyable characteristics of the environment, as well as successful coping, adaptation, and positive long-term outcomes among crew members, are just as important and informative as studying environmental stressors and human failure, maladaptation, and postflight problems.68 Such information is essential to the development of effective countermeasures during all phases of a mission.
Cognition and Perception
Although the perceptual changes associated with microgravity and disruption of circadian rhythms have been thoroughly examined in both in-flight and ground-based studies, there is very little systematic knowledge of changes in cognition and perception associated with long-duration spaceflight. Information on cognitive and perceptual distortion during short-duration missions is of little help because of potential qualitative as well as quantitative differences associated with prolonged exposure to the space environment. Decrements in cognitive performance are of particular concern because of the likelihood of emergency situations. Therefore, additional research is required to determine what cognitive changes occur during long-duration missions, what individual and environmental characteristics are associated with such changes, and whether preflight training is effective as a countermeasure to any performance decrements.
A particular problem requiring research in the next decade is the increased likelihood of errors as missions grow longer in duration. These can involve something as simple as disconnecting the wrong cable (which happened aboard Mir in July 1997) or flicking the wrong switch. An even more likely outcome is the inability to break away from one's training and invent ways of solving unexpected problems when an unanticipated situation calls for a careful information search and a complex, creative decision strategy.69 The complex of abilities generally referred to as "fluid intelligence" is most likely to be influenced by hostile or restrictive environments. This includes problem solving in situations that require novel solutions, decision making in situations in which multiple aspects of the situation must be considered, and dealing with situations in which it is important to keep track of several things at one time. These cognitive processes are tied to the status of the forebrain, and this area is especially subject to insult from environmental damage (e.g., carbon monoxide poisoning, excessive alcohol consumption). It is also possible to take a more psychological approach and observe that all the fluid intelligence functions require tracking many variables in working memory. Therefore, if one's working memory space is being taken up by distractions (including social tensions, depressed affect, or simply discomfort due to impoverished environments), there is less "mental space" available to deal with the problem at hand. Alternatively, the absence of certain distractions under conditions of social and physical monotony during long-duration flights may also produce a decline in cognitive skills.
Environmental impacts on either simple, overlearned performance or on the solving of complex, novel problems have not been studied with highly selected, trained, and motivated subjects such as astronauts. As a result, it is not known what levels of stress and mission duration are likely to impair crew responses to different kinds of problems. Simulations of both ongoing stressors and acute events are needed to predict how crews would cope with them. It is important to note that the types of cognitive skills that are at risk due to the sorts of conditions expected on long-duration spaceflight are also the
kinds of skills that are most subject to deterioration with age. Therefore, there is a difficult trade-off between a wealth of knowledge and experience and a potentially diminished cognitive ability to utilize this knowledge, both of which are age-related, that may have important implications for the screening and selection of personnel for such missions.
The possibility of brief periods of anterograde amnesia (i.e., failure to consolidate information) in-flight must be considered. Functionally, the appearance of mild anterograde and/or brief retrograde amnesias also can be produced by environmental agents, including some drugs used to combat motion sickness. Retrograde amnesias can be produced by striking emotional events, so that individuals may forget what they were doing just prior to a dramatic incident. Research is required to determine the incidence of low-level amnesias during long-duration missions and to develop effective countermeasures.
Emotions are valenced reactions to personally significant events, including physiological reactions, behavioral reactions, cognitive reactions, and subjective feelings of pleasure and displeasure. Both positive and negative mood can take on added significance during long-duration space missions because trivial issues are often exaggerated by people living and working in isolated and confined environments. 70 However, we do not know whether this exaggeration is the result of changes in physiological processes, emotional behavior, or cognitive activity. Whether some or all such sources contribute to emotional feelings in any environment is a central issue in the theory of emotional experience. Investigation of the emotional experiences of astronauts during long-duration missions might enable us to advance our understanding of the foundations of emotional experience by contributing to the development of models that link characteristics of the individual (e.g., concerns, values, goals) and the environment (e.g., limited resources, information, alternatives) to physiological (e.g., facial expressions, autonomic arousal, HPA axis alteration) and cognitive (appraisal of issues or events as trivial or important, self-perception, interpretation of a situation as being "emotional") changes.
The underlying causes of expressions of negative emotion in ICE environments include factors such as fatigue and disruptions of circadian rhythms, difficulty in adjusting to microgravity-related physiological changes and alterations in the HPA axis, learned patterns of coping with stress (e.g., avoidance, expressiveness), perception of the risks associated with the physical environment, loneliness and separation from family and friends, receipt of unexpected and distressing news, and interpersonal conflicts.71 72 73 However, the specific contribution of each of these factors to the expression of specific emotions in specific individuals remains to be determined. A greater understanding of individual, social, and environmental predictors of negative emotions in long-duration missions is essential to the development of effective countermeasures. Although the probability that the expression of these negative emotions will escalate into episodes of psychopathology during long-duration space missions is quite low, they have been associated with decline in task performance and motivation; disruption of attention, short-term memory, and other cognitive processes; increased interpersonal conflict, leading to both voluntary and involuntary isolation from other crew members; and the occurrence of various psychosomatic or psychophysiological symptoms.74 75
Equally important is an understanding of the factors that contribute to the expression of positive emotions. For instance, research from analogue settings suggests that long-duration isolation and confinement in an extreme environment are likely to produce personally rewarding experiences for certain crew members.76 Such optimal experiences are characterized by feelings of being strong, alert, in effortless control, unself-conscious, and at the peak of one's abilities.77 Investigation of such
experiences during actual spaceflight conditions may help us to understand why certain environments perceived by some to be stressful, with adverse effects on health, well-being, and performance, can be perceived by others as challenging, with positive outcomes. However, additional research is required to determine whether individual optimal experiences can lead to enhanced task performance and the likelihood of overall mission success, which individuals are likely to have these experiences, and which aspects of long-duration space missions are likely to produce such experiences for individuals. Additional research is also required to determine whether preflight training can increase the probability that such experiences will occur.
In space, personality traits interact with the various stressors and unique aspects of the physical and social environment to determine how crew members behave and perform. Several traits relevant to spaceflight are essentially motivational, such as risk-taking and telic dominance (focusing narrowly on reaching one's goal as opposed to valuing the challenging process of trying to reach it). Others affect one's reactions to stressful situations. These include optimism, hardiness (a composite of more specific characteristics, such as a feeling that one can understand and control events), resilience (the ability to "get past" setbacks and continue on), and resourcefulness (being able to look for and find alternative ways of solving a problem). Still other traits define social tendencies (e.g., sociability, dominance, aggressiveness, affiliative needs, and dependency).
In the next decade, research on human behavior in space should focus on the extent to which personality characteristics vary among astronaut personnel and whether these variations are associated with differences in behavior and performance preflight, in-flight, and postflight. Such research could focus on single traits believed to be specifically relevant to spaceflight, such as those described above. For example, it may be hypothesized that individuals who are high in thrill-seeking and dominance, and low in resourcefulness, will engage in aggressive competition with their crewmates to relieve boredom in a long-duration mission. However, because of the vast number of known personality traits, it is difficult to determine a priori which should be studied; at this point, perhaps the most fruitful approach is to adopt a multitrait approach and look at the traits that in the past decade of research have been noted as powerful correlates of many kinds of behavior, known as "the Big Five."78 These cover underlying tendencies across the contexts of mental health and emotional stability (neuroticism ), social interaction styles (extraversion, agreeableness), and cognitive or performance orientations (openness, conscientiousness). How they relate specifically to the ICE performance measures of ability, stability, and compatibility and how they influence behavior in all of the contexts within the domain of spaceflight are important questions for basic research that also offer potential contributions to improving individual selection and crew composition. In addition to their operational relevance, comparisons of astronaut personality traits and behavior preflight and in the controlled social and physical environment of spaceflight offer the potential for addressing some of the fundamental questions underlying the fields of social and personality psychology, such as the extent to which personality is stable and consistent over time, is a social construct, or is a function of the situation.
Personality traits are stable but not unchangeable; major life events have been known to cause long-term changes such as increased spirituality and religiousness, greater sensitivity to others, and a new set of motivational priorities. A substantial personality change as a result of spaceflight may have a significant impact on the life of the astronaut and his or her family. Longitudinal studies of future long-duration missions are needed to establish the probability of such changes and their possible consequences, to identify individual and mission-related characteristics that are associated with such changes,
to prepare the individuals likely to be affected by these changes, and to design strategies for possible intervention.
No selection program—no matter how thorough—can completely prevent the development of psychiatric problems in space. There have been several anecdotal accounts of episodes of depression, bereavement, anger, and anxiety among astronauts in long-duration missions where clinical intervention was necessary or advisable.79 80 Studies of submariners81 and antarctic winter-over personnel82 have indicated that between 5 and 10 percent of individuals who are psychologically screened and selected for assignments in isolated and confined environments experience clinically significant psychopathology. The Russians also have described a syndrome called asthenia that frequently results from the hypostimulation that may affect cosmonauts during long monotonous periods in space.83 Elements of this syndrome include irritability, emotional lability, poor appetite, and sleep disruption. In some cases, negative personality changes have occurred that have led to marital problems and severe psychiatric difficulties.84 Spouses also can be affected. For example, some investigators have coined the term "submariners' wives syndrome" for the depression and stress experienced by spouses who are trying to adjust to the reintegration into the family of their husbands who have just returned from sea patrol.85 86
Although the incidence of severe psychopathology is assumed to be low during long-duration missions, ongoing studies of the etiology and incidence of psychiatric disorders preflight, in-flight, and postflight will be necessary to validate this assumption and to develop effective countermeasures in the hopefully rare instances in which such disorders do occur. The collection of baseline measures of personality during the screening and selection phase and the ongoing monitoring of affective, cognitive, and psychophysiological responses to discrete stressors during preflight training and in-flight operations are particularly relevant to this objective.
Medical kits on U.S. and Russian crewed space missions have included a variety of psychoactive medications: anxiolytics such as diazepam, sleeping pills such as flurazepam, antipsychotics such as haloperidol, and intramuscular promethazine for space motion sickness.87 Seventy-eight percent of shuttle crew members have taken medications in space, primarily for space motion sickness, headache, sleeplessness, and back pain.88
Physiological changes due to spaceflight may change the pharmacokinetic behavior of psychoactive drugs, thus influencing their dosage and route of administration.89 For example, microgravity can increase blood flow in the upper part of the body and decrease it in the lower part. Thus, an intramuscular injection to the arm rather than the hip might alter the bioavailability of the medication. Also, gastric emptying, intestinal absorption, first-pass effects through the liver, and metabolism and secretion rates may be influenced by fluid shifts and other effects of microgravity. This can lead to medication dosages and direct and side effects that differ from what is predicted from experiences on Earth. Like other medications, psychoactive drugs may be sensitive to such changes,90 and empirical study in the space environment is required to fully understand these effects.
Psychological and psychiatric countermeasures have two primary objectives: (1) Measures such as procedures for the screening and selection of astronauts are intended to prevent the occurrence of decrements in performance that may negatively affect individual health and well-being and mission success. (2) Measures such as the monitoring of flight crews, training programs, in-flight services, and clinical interventions are intended to support individual crew members and ensure optimal performance during a mission.
Screening and Selection
In the history of space exploration, there have been no descriptions in the scientific literature of either the rationale used for screening and selection of American astronauts or the reliability and validity of that rationale. The Soviet scientific literature has been less reticent in documenting the process of screening and selection, but these methods also have not been subjected to any assessment of validity and reliability.
The screening and selection of astronaut personnel in the U.S. space program has traditionally emphasized a "select-out" approach in which candidates who have a diagnosable psychiatric disorder, or are considered to be at risk for developing such a disorder, are identified and not selected for astronaut training.91 Screening procedures used in this approach have relied on standardized assessments and an examination of relevant biographical data. Santy reported the incidence of psychiatric disorders in a study of 223 astronaut candidates to be 7.7 percent. 92 Furthermore, this approach has been credited for the relatively low risk of astronaut personnel developing psychiatric disorders in-flight. Nevertheless, it is important to continually review this process and update it when necessary, using the latest state-of-the-art psychiatric screening techniques. For instance, the impact of revisions in standardized psychiatric classification systems on screening and selection of astronaut personnel has yet to be determined.
In recent years, greater emphasis has been placed on a "select-in" approach to identify candidates whose character traits enhance the likelihood of being able to perform under stress and interact productively as a member of a crew. Research on astronaut personnel and individuals in analogue settings has identified a number of characteristics as predictors of successful performance in extreme, isolated environments. McFadden and colleagues found that expressive traits are significant predictors of astronaut effectiveness in interpersonal domains.93 A similar study by Rose and colleagues found that astronaut professional effectiveness was associated with high negative expressivity and "communion" (subordinate and gullible), low openness, low negative instrumentality (egotism), and high agreeableness.94 A study by Ursin and colleagues hypothesizes that a moderate level of aggressiveness or vitality would be appropriate for a short-duration mission but not for a long-duration mission.95 The latter would require selecting-in characteristics such as readiness to bear privation and emotional stability. Data on these select-in psychological characteristics are very promising, but require validation against in-flight performance measures. This task is somewhat challenging because it means that specific select-in criteria must not be used as the initial basis of astronaut selection until they have been found to predict astronaut performance. Only after research demonstrates the validity of a criterion should it become part of the operational selection process.96 Furthermore, screening and selection of multinational crews for long-duration missions must take into account the fact that preferences for certain personality traits or characteristics linked to a specific job description (e.g., pilot or astronaut) are likely to vary among the different cultural groups represented in such missions.97 98
Support of Individuals and Families
Research should be conducted to determine which forms of psychological and psychiatric support are most appropriate for astronaut and ground support personnel during the preflight, in-flight, and postflight phases of a mission. Data from the Mir incidents in 1997 may be especially relevant in this regard, because of the frequency and severity of the problems encountered on this space vehicle. Research has consistently pointed to the direct and moderating influence of social support on physical health and emotional well-being. However, under conditions of prolonged isolation and confinement, influences may be minor or inconsequential. In part, these conditions place certain restraints on the transmission of support to astronauts in long-duration missions. They also serve as stressors to family members who would otherwise provide support to the astronauts. Both limit the capacity of family units to provide support as well as the capacity of astronauts to utilize such support to maximize their performance and well-being. Research should also be conducted to identify the types of support necessary and effective in reducing stress and enhancing the ability to cope with prolonged separation in families of astronauts during training and during the flight.
Preflight training of astronauts should include familiarizing the astronauts themselves with possible psychological problems that may arise, ranging from alterations in perception to the complexity of group interactions. Training should include accommodation to potential cognitive problems (e.g., taking special precautions against inattention when one is forced to go through long periods of sleeplessness) as well as training in how to deal with changes in muscle coordination or perception as described in Chapter 5.
In-flight psychosocial support programs have been lauded by Russian crews and favorably commented on by astronauts participating in the SMSP.99 This support is provided by ground-based teams who maintain crew mental health by providing them with reminders of connections to Earth, such as music, audio tapes, and other personal items. The support team can also provide valuable "coaching" in the event of an on-board psychosocial problem. Although most of these will be in the normal range (e.g., interpersonal friction, being informed about a family crisis), serious psychiatric problems could occur, as noted above. Records of the effectiveness of such support should be subjected to the same sorts of debriefing and analysis as mission performance data to identify areas of potential improvement.
Psychosocial support also should be extended into the postflight period. As noted earlier, studies of personnel in submarines and polar stations indicate that the returning crew member may have difficulty dealing with normal levels of physical and social stimulation. When problems do occur a careful analysis should be made of the effectiveness of the countermeasures, in order to improve the process.
Research on the individual factors of behavior and performance during long-duration missions should include an examination of the following topics, listed in order of priority:
- The effects of individual characteristics of crew members on cognitive, psychophysiological, and affective measures of behavior and performance:
- The relationship between self-reports and external (i.e., performance-related, physiological) symptoms of stress;
- The use of specific coping strategies and behavioral and physiological indicators of coping stage transitions during long-duration missions;
- The effect of physical and psychosocial stressors on problem-solving tasks and fluid intelligence;
- Associations between general and mission-relevant personality characteristics and performance criteria of ability, stability, and compatibility; and
- Individual and mission-related predictors of postflight changes in personality and behavior.
- Development and evaluation of countermeasures to performance decrements during the preflight, in-flight, and postflight phases of a long-duration mission:
- The validity and reliability of current and alternative screening and selection procedures based on performance criteria;
- The effectiveness of psychological and psychiatric countermeasures that have been employed in past flights, using data collected from observations, postmission briefings, and interviews;
- The influence of spaceflight on the pharmacology, pharmacokinetics, efficacy, and side effects of psychoactive medications; and
- The effectiveness of countermeasures that provide psychosocial support to family members on the performance and well-being of astronauts.
Crew Tension and Conflict
Several factors affect crew tension or conflict. The extent to which heterogeneity (i.e., differences in the psychological, social, and demographic characteristics of individuals who comprise a flight crew) is a risk for interpersonal conflict in ICE settings remains largely unresolved and requires additional research. Although analogue studies have indicated that heterogeneous crews are more likely to experience interpersonal conflicts under conditions of isolation, studies in space simulation environments have found that crewmates who share certain personality characteristics such as a high need for dominance do not work well together,100 101 whereas people who are compatible and sensitive to each other in a complementary manner do much better. However, little is known about specific personality traits that enhance compatibility and reduce interpersonal conflict in space.
Gender factors also are important. Instances of sexual stereotyping have been reported, both in space and in Earth analogues.102 Although it is not unusual for such behavior to take place in the general population, research in analogue environments has demonstrated that it often takes on added significance in isolated and confined environments, resulting in misunderstandings and increased tension between men and women who must learn to work together.
Another factor affecting crew conflict relates to differences in career motivation between crew members. In space analogue environments, people with different training backgrounds and career objectives have responded in different ways to missions involving prolonged isolation.103 In some cases, conflicts have erupted between groups that have compromised mission goals.104 Similarly, operationally oriented pilots and engineers in space may view the mission objectives differently from scientifically oriented payload specialists or "guests" who have nonoperational duties. Tensions also can occur when some crew members view their roles as more important than those of other crew members.
Finally, cultural and language differences may affect space crews by producing intracrew friction and ineffective responses to danger, both of which can have a negative impact on the success of a mission. Reports from long-duration Russian space missions involving people from other nations have
highlighted conflicts among crew members based on differences in language competency and culturally determined expectations, values, attitudes, and patterns of behavior.105 106 On the other hand, one may argue that cross-cultural issues will have a minimal impact on crew behavior and performance since, as members of a common profession, astronauts share a body of knowledge, a set of expectations, and common skills that comprise the "microculture" of the space crew. 107 However, as crews become larger and include individuals with a diverse set of backgrounds, skills, and responsibilities, it may be increasingly difficult to produce an allegiance to a common professional culture.
A common language is also essential to maintaining optimal levels of interpersonal coordination and cooperation. A survey of 54 astronauts and cosmonauts found that all of the respondents believed that it was important for members of a space crew to be fluent in a common language.108 Interestingly, U.S. and Russian space travelers rated the importance of having a common language significantly higher than did astronauts from other countries, possibly reflecting the concern the former groups felt for the operational aspects of the missions for which they were responsible. Limited fluency in the language of the host crew may also slow down communication109 and might prove life-threatening during an emergency where timing and accuracy of communication are critical.
As with conflict, factors that potentially affect crew cohesion require further investigation. Dysfunctional crews may scapegoat one of their members and blame him or her for the inability of group members to interact more productively. In isolated and confined groups, such scapegoating may actually serve to unify all but the ostracized member. 110 Lack of cohesion also may lead to subgrouping, where the crew splits into factions along social or task-oriented lines (e.g., scientists versus pilots).111
Social monotony may also contribute to reduced crew cohesion. During antarctic and submarine missions, a long monotonous period has been reported where tasks become routine and where crew members frequently experience boredom, depression, homesickness, and withdrawal.112 This phase also has been described during long-duration Russian space missions,113 114 and it has resulted in decreased cohesion and increased interpersonal problems.115 These social ramifications of monotony may be relieved by increasing audio-video communications with family, friends, interesting strangers, and ground control on Earth. Different problems arise when social monotony is not absolute. For example, in a space station, unlike a long-duration mission to Mars, people would occasionally leave and new ones arrive. Such changes relieve monotony but can produce their own stressors, since the group has to get used to new arrivals and socialize them into its accustomed ways of doing things.116 The microcultures of crews and missions have to be better understood in order to ease this process. The effects of periods of social monotony on space crews should be addressed further in order to maintain morale, provide meaningful use of leisure time, and prevent negative consequences of low stimulation (e.g., asthenia, crew member withdrawal).
Crew cohesion seems to decrease over time during the course of long-duration space missions, especially as the effects of monotony and familiarity begin to take their toll. However, common interests and activities can help to bond crew members together. For example, a study of astronauts and cosmonauts who had flown in space found that the shared experience and excitement of spaceflight contributed significantly to enhancing crew member communication.117 Interestingly, these same two factors were the only ones that were rated as significantly enhancing communication between space crews and monitoring personnel on the ground.
Similarly, efforts are required to identify the factors that are likely to promote and maintain crew cohesion during the preflight and in-flight phases of long-duration missions. Although heterogeneity in
crew composition may contribute to increased levels of tension and conflict as noted earlier, variety in background and experience may also minimize social monotony and lead to rewarding interpersonal experiences that contribute to enhanced group performance and individual well-being. For example, during leisure periods, different hobbies and interests may be shared among crew members that could stimulate learning and lead to the formation of new social bonds. The extent to which crew cohesion is influenced by the characteristics of individual members may also vary with mission duration such that cohesion may be enhanced by homogeneous features of crew composition early in the mission and heterogeneous features later on. The impact of homogeneity or heterogeneity and mission phase on crew cohesion should be studied empirically under actual spaceflight conditions. Such research would help to advance our understanding of the extent to which the interactions of space crews and other small groups can be explained by processes of interpersonal attraction (e.g., similarity, cooperation, interpersonal acceptance, shared threat), as predicted by attraction models of cohesion, or in conjunction with other effects (e.g., conformity, in-group differentiation, stereotyping, in-group solidarity) produced by the process of self-categorization specified in self-categorization theory.118
Tension involving a confined group of people may be displaced to outsiders who are monitoring their activities, since it is easier to express anger and anxiety toward more remote individuals than toward people with whom one must frequently interact. Such displacement has been reported during both Russian and U.S. space missions119 120 121 and during previous ground-based simulation studies.122 123 Astronaut perceptions of the demands placed on them by ground-control as excessive, unreasonable, or unclear have led to expressions of hostility and conflict in the past. For their part, ground control personnel have complained of the failure of astronauts to adhere to schedules or follow directions, raising concerns of an increased risk of accidents and mission failure. More often, degradation in ground-crew interactions has led to instances of miscommunication. 124
On the other hand, these apparent degradations in ground-crew interactions may actually have an adaptive function. Because they are remote from the crew in a physical sense, ground control personnel may serve as an outlet for crew aggression and irritability that is the result of factors external to ground-crew relations.125 The direction of anger and hostility toward external authorities and individuals may also serve to unite astronaut crews, thereby facilitating cooperation and enhancing performance. However, no attempt has been made to study the benefits of such alterations in ground-crew interactions relative to costs in a quantitative or qualitative fashion.
Another important element of ground-crew interaction that requires further investigation is the interaction between crew members in-flight and family and friends on the ground. As noted earlier, such interaction is critical to reducing social monotony and individual feelings of isolation and confinement. However, as studies of personnel in analogue settings suggest, contract with family members may lead to problems. 126 One important issue is under what conditions bad news should be communicated to the crew. This is a complex issue for study, whose parameters (e.g., seriousness of the event, who is involved, whether the astronaut can help solve the problem) need to be manipulated systematically in simulations. Studies conducted to date have provided no consensus on the question of whether negative personal information should be withheld from crew members until the end of a mission.127 Information also is lacking on the optimal duration and timing of family calls.
To date, there have been no studies of crew leadership conducted during actual spaceflight.128 Research on small groups in other isolated and confined environments suggests that effective leadership of such groups in general is a function of certain characteristics of the leader (i.e., hard-working, optimistic, sensitive to needs of the crew), forms of leadership behavior (i.e., democratic-participative rather than authoritarian decision making), and situations (democratic in response to task and crew maintenance and authoritarian in response to emergencies and unexpected situations).129 130 131 132 However, recent advances in the theory of leadership suggest that greater attention should be devoted to understanding the context and consequences of leadership during spaceflight. For instance, the appropriate exercise of different leadership roles and lines of authority at different times in the mission has to be studied in order to understand factors that lead to status leveling, leadership competition, and role confusion. Research is required to determine whether the characteristics of effective leadership during long-duration missions differ from those of short-duration missions. During short-term spaceflights, the identified leader is the mission commander, the lines of authority are clear, and activities are task-oriented. However, studies of polar expeditions indicate that task leadership is more important during the early phases of a mission, but less important than supportive leadership and shared decision making as the mission progresses.133 134 In a European Space Agency (ESA)-sponsored study of a three-man crew isolated for 135 days in the Mir space station simulator in Moscow, both the leader control measure (which addressed the task-oriented, instrumental characteristics of the identified leader) and the leader support measure (which addressed his supportive, expressive qualities) correlated positively with group cohesion.135 However, the commanders of long-duration missions may not be able to provide this social or emotional support as well as some other member of the crew. As a result, lines of authority may alter, and the identified leader may experience status leveling, leading to interpersonal conflict and the breakdown of command structure. In addition to its operational relevance, research on these issues would also serve to advance our fundamental understanding of leadership in small groups by enabling us to test the hypothesis that relationship-oriented leadership is more successful than task-oriented leadership in situations moderately favorable to the leader, or in very favorable or unfavorable situations,136 and the hypothesis that the individual traits and social situations necessary for the exercise of transformational leadership (e.g., nonconformity) are incompatible with those necessary for transactional leadership.137 138
NASA has developed a number of strategies to deal with the interpersonal issues that could potentially lead to a degradation in individual and group performance.139 Procedures for the selection of flight crews are less formal than procedures for the screening and selection of individuals into the astronaut corps described above. The mission commander, who is picked first, has some input into who his or her fellow crew members will be; however, the final decision is the responsibility of management.
In contrast to U.S. selection procedures, the Russian space program has expended considerable effort on the construction of compatible crews. When forming space crews, Russian psychologists take into account the similarity of values among potential crew members; their social and motivational attitudes toward the job; the presence of complementary personality and character traits and cognitive styles; and the ability to learn rapidly and efficiently. One of the compatibility testing methods used by
Russian psychologists when forming a crew is the Mutual Talking Test in which candidates are required to cooperate in completing a computer-simulated task. Cosmonauts participate in a number of other experiments that simulate interdependent activities. In addition, Russian psychologists believe that biorhythms are useful in selecting cosmonauts for specific missions. Crew members with similar biorhythms are often assigned to the same crew. Despite a strong conviction on the part of the Russian space program about the effectiveness of these procedures, they have been subjected to little objective evaluation.
In the future, interpersonally oriented testing methods should be used along with more individually oriented psychological tests preflight to assess the compatibility of crew members. Formal testing procedures have correctly predicted crew incompatibilities during the Ben Franklin submersible simulator mission,140 and interpersonally oriented psychological tests, such as the FIRO-B and sociometric questionnaires, have shown promise in crew selection in several simulation studies.141 142 143 144 145 146
In the future, more didactic and experiential training similar to the programs involving participants in the SMSP should be provided concerning the influences of specific sociocultural factors (e.g., personality, compatibility, gender bias, cultural and language differences, career motivation) in order to minimize crew tension, sustain cohesion, and prevent subgrouping and scapegoating. Astronauts who have flown on previous international space missions have endorsed the importance of receiving cultural and language training that is related to the crew composition of their missions.147 In addition, preflight activities involving team building and conflict resolution should be incorporated into the training of space crews.148 149 Experiential sensitivity training before a mission has been found to be useful in helping individuals interact better during Earth-bound confinement experiments. 150 151 Also, crew interaction training modules developed for use with airline cockpit crews (e.g., crew resource management [CRM] and line-oriented flight training [LOFT])152 153 154 should be modified for use in the space program. Crews preparing for long-duration space missions should spend some time together confined in an Earth-bound simulator so that potential interpersonal conflicts can be observed and dealt with prior to the actual mission. Finally, both crew members and monitoring personnel on Earth should be briefed on the psychological phenomenon of displacement in order to counter the effects of ground-crew miscommunication and interpersonal conflicts.
Issues that cause tensions between crew members and outside monitoring personnel have been ameliorated in the past through "bull sessions," both in simulations155 and during actual space missions.156 Future crews and their ground control personnel should be trained together preflight to use interactive techniques, and experts in small-group dynamics who work with and are trusted by the crews should be available on the ground to assist in conducting such sessions during the mission if the need occurs.
Current NASA in-flight monitoring activities consist of daily communications between crew members and flight surgeons and, less frequently, with psychological support personnel. However, these communications are not confidential and provide little or no opportunity to address and resolve sensitive issues related to interpersonal conflicts. The Russians find ongoing monitoring of voice communications to have some operational value in assessing crew tension, cohesion, and morale, 157 but this approach has not been fully explored by NASA. A 23-item Crew Status and Support Tracker (CSST)
questionnaire is completed weekly by U.S. astronauts on the Mir space station and down-linked to the ground, where crew members write in responses to questions that are related to mood, morale, personal privacy, interactions with each other and with people on Earth, sources of stress, and physical state. However, the psychometric properties of this instrument have not been assessed.
In the future, new attempts should be made to monitor crew member interactions in-flight to look for potential interpersonal problems. For example, NASA should explore further the voice analysis techniques used by the Russians in monitoring their space crews during long-duration space missions. The usefulness of the CCST and other tracking instruments should be formally validated. Finally, additional efforts are required to provide a secure communication link.
The in-flight support activities of the United States are modeled after the Russian system158 and include surprise presents and favorite foods sent up on resupply rockets; two-way communication with family and friends on the ground via audio-video links, e-mail, or ham radio; and on-board recreational software and videocassettes for leisure time use. At times, crew members are encouraged to talk with one another to resolve interpersonal difficulties. A computer-based family picture album of spouses, children, friends, and co-workers is currently provided and has been well received by crew members. Although these support activities possess face validity and have been enthusiastically endorsed by participants in long-duration missions to date, their effectiveness in reducing intragroup, individual-family, and crew-ground tension or conflict and in promoting crew cohesion has not been systematically investigated.
Finally, research is required to evaluate the effectiveness of postflight debriefings in resolving issues of interpersonal conflict that occur in-flight. In the past decade, debriefing protocols have been developed and implemented to help crew members readjust to their life on Earth. Although the focus of these protocols has been on individual well-being, as described above, supportive attention also is given to the reintegration of these individuals with their families. These debriefings offer a potentially effective countermeasure for addressing residual intracrew, crew-family, and ground-crew tensions that may develop during long-duration missions. An evaluation of the effectiveness of these debriefings in addressing such tensions will require systematic efforts to collect information on the issues in-flight and postflight, and the randomized assignment of crew members to an experimental or control condition.
To enhance data collection and validate the research described above, the following operational and policy changes should be implemented:
- Valid and reliable interpersonally oriented testing methods, along with more individually oriented psychological preflight tests, should be used to assess the compatibility of crew members.
- More didactic and experiential training should be provided to crews on the following:
- Specific sociocultural factors in order to minimize crew tension, sustain cohesion, and prevent subgrouping and scapegoating;
- Preflight activities involving team building and conflict resolution; and
- The psychological phenomenon of displacement in order to counter the effects of ground-crew miscommunication and interpersonal conflicts.
- Monitoring of crew member interactions in-flight should be expanded as a tool for supporting crew cohesion and resolving interpersonal conflict.
Research on the interpersonal factors of behavior and performance during long-duration missions should include an examination of the following issues in order of priority:
- The influence of different crew compositions (i.e., personality types, gender, culture, language, occupation, career motivation) on crew tension, cohesion, and performance during the mission;
- Factors affecting ground-crew interactions, including the impact of crew tension and unhappiness on crew-ground communication; impact of ground-crew communication on crew cohesion and task performance; and conditions that affect the distribution of authority, decision making, and task assignments between space crews and members of ground control; and
- The development of new countermeasures and assessment of the effectiveness of existing countermeasures, including the following:
- Interpersonally oriented psychological tests in selecting crews;
- Team-oriented training modules in reducing crew tension and enhancing cohesion and performance during the mission; and
- Evaluation of Russian techniques such as voice analysis for monitoring the interpersonal performance of crews.
Each of the major space agencies participating in the International Space Station (NASA, the Russian Space Agency [RSA], ESA, the Canadian Space Agency [CSA], and the National Space Development Agency of Japan [NASDA]) possesses different "macrocultures," i.e., values, attitudes, and behavior as they relate to the principles and practices of management and organization that embody the cultural systems of the respective nations. They also have different experiences with the application of these values, attitudes, and behavior to the challenge of crewed spaceflight that may account for differences in expectations and operational procedures during long-duration missions. NASA and RSA, for instance, have been involved in manned spaceflight for a longer time than the other space agencies and are the only ones that currently possess crewed space vehicles. Furthermore, NASA and RSA are characterized by a number of operational features that reflect differences in their respective organizational cultures. These include differences in ground-crew interactions (e.g., Russian personnel have been reported to be more confrontational than Americans in their ground-crew interactions); extent of ground-crew communications (e.g., U.S. ground control personnel remain in contact with space crews for longer periods of time); the NASA emphasis on overtraining for missions versus the RSA emphasis on "on-the-job" training; and the structure of rewards and restraints (e.g., the Russian practice of docking the pay of cosmonauts who fail to perform prescribed tasks). These differences have been reported by astronauts and cosmonauts to significantly influence crew dynamics.159 However, this impact has not been examined in a systematic manner. Similarly, there is a lack of data from analogue environments on this issue. Differences in organizational cultures have already had an impact on crew performance in the SMSP, and the committee believes that these impacts are likely to become more significant as future missions become longer in duration and involve more organizations.
Innovative qualitative data collection and analysis methods should be employed in examining the influence of organizational macrocultures and space crew microcultures on individual and group behavior and performance. Such methods have been found to be useful in studying microcultures in analogue settings160 and include participant observation, nondirected interviews, pile-sort tasks, and cultural consensus modeling.
Despite the general consensus that long-duration missions represent a qualitatively different experience in terms of behavior and performance from missions of short duration, it is unclear whether mission duration is a significant predictor of performance and behavior. For instance, several studies of small groups in isolated undersea research labs and space simulation studies have reported significant increases in symptoms of depression, anxiety, and group hostility over time. 161 These results have supported the hypothesis that ICE settings influence human behavior in a linear dose-response manner such that the longer the exposure, the more significant are the decrements. Other studies have been used to support the hypothesis that decrements in performance under these environmental conditions occur in stages. 162 163 Rohrer described three stages of reaction to isolation and confinement: (1) an initial period of heightened anxiety related to perceived danger during the first few days of a mission; (2) a prolonged period of boredom and depression; and (3) a period of anticipation during the end of a mission characterized by hypomanic affect and increased aggression and hostility.164 Bechtel and Berning described the "third quarter phenomenon" in which performance is likely to decline during the third quarter of a mission in an isolated and confined environment regardless of the total duration of the mission itself.165 Other studies have reported no significant decrements in behavior and performance during long-duration missions in analogue settings.166 Still other studies have reported an improvement in performance over time.167 In the Mir simulator study described previously, there was significantly less total mood disturbance and overall crew tension during the last half of the seclusion than during the first half, and a dramatic reduction in mood disturbance and anxiety occurred after a resupply event in which the crew received additional food and equipment as well as letters of support from family and friends. 168
There is a need to identify the managerial requirements for long-duration missions and the necessary steps for management structures to transition from short-duration to long-duration mission operations. One of the important management functions of the organizations involved in long-duration missions is the scheduling and monitoring of tasks performed in-flight. Identifying the optimum amount of work that can and should be performed during long-duration missions is important for a number of reasons. Evidence from previous short-duration missions has pointed to the potentially adverse impacts of scheduling too many tasks within the time available. These impacts have included conflicts between astronauts and ground control personnel, refusal to perform assigned tasks, fatigue, sleep deprivation, a decline in cognitive performance, and an increase in negative affect.169 On the other hand, evidence from long-duration missions and analogue environments suggests that a lack of sufficient amounts of meaningful and productive tasks can result in boredom, producing many of the same symptoms associated with overwork.170 Individual and group performance may also be affected when disparities in workload occur among crew members, such that some are given too much to do and others are not given enough to do during a long-duration mission.
The microgravity environment is another key component of workload and the scheduling of tasks to be performed during long-duration missions. Despite the wealth of experience in working in such environments and the opportunities to develop task schedules based on their performance in simulators, the inability to perform tasks in the allotted time remains a chronic problem. Many astronauts attribute this to the inadequate consideration given by management to the challenge of performing these tasks in a microgravity environment and to individual variation in the time required to complete certain tasks. However, it remains unclear whether these concerns are justified or reflect the lack of communication and understanding between space crews and ground control described above. Similarly, space crews may estimate the time required to perform certain tasks in-flight differently from estimates made on the ground because of distortions in temporal perception caused by characteristics of the environment.171 Further research is required to determine the organizational requirements for developing realistic schedules for operations in space and on the ground, and the impact of such schedules on the management of long-duration missions. Further research is also required to determine the organizational impacts of giving space crews more control over the scheduling of tasks.
Another management issue relates to the formal distribution of authority and tasks during long-duration missions. Although issues relating to leadership, task assignment, and decision making have been addressed above in the section on interpersonal factors, they are also relevant here because NASA, other national space agencies, and other organizations involved in long-duration missions all possess formal definitions of organizational positions and specify the relationship of one position to another. Associated with each position is a set of expectations that define certain behaviors as either essential, admissible, or unacceptable.172 The organizational structure of authority, decision making, and task assignment developed for short-duration missions may have little relevance for the organizational needs of long-duration missions. For instance, the traditional organizational structure that separated space crews into "pilots" and "scientists" or "payload specialists" and the distribution of authority, decision making, and task assignments based on this distinction may have little relevance for the effective management of long-duration missions. Similarly, the conditions under which authority structures, decision-making processes, and task assignments result in interpersonal and crew-ground control conflicts during long-duration missions may be quite different from the conditions leading to conflict during short-duration missions.
Research on the organizational influences on behavior and performance during long-duration missions should include an examination of the following issues:
- The extent to which participating agencies and personnel representing these agencies share similar systems of knowledge, attitudes, and behavior regarding mission operations, goals, and objectives; how these systems are organized; and how they influence individual and group performance and behavior;
- Whether changes in behavior and performance are associated with mission duration or specific periods during the course of a mission; what form this association assumes if it does occur; and whether the implementation of countermeasures should correspond to these specific periods; and
- The requirements for effective management of long-duration missions as they relate to the following:
- Task scheduling;
- Disparity between expected and observed time required for operational procedures, spacecraft maintenance, scientific experimentation, and emergency response; and
- Distribution of authority and decision making.
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