Human Health and Performance Risks of Space Exploration Missions: Evidence Reviewed by the NASA Human Research Program - Radiation and Cancer, Behavioral Health, EVA, Spacesuits (NASA SP-2009-3405)
National Aeronautics and Space Administration (NASA), World Spaceflight News, Jancy C. McPhee, John B. Charles
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Behavioral Health and Performance
Chapter 1 - Risk of Behavioral and Psychiatric Conditions
Space Radiation
Chapter 4 - Risk of Radiation Carcinogenesis
Chapter 5 - Risk of Acute Radiation Syndromes Due to Solar Particle Events
Chapter 6 - Risk of Acute or Late Central Nervous System Effects from Radiation Exposure
Chapter 7 - Risk of Degenerative Tissue or Other Health Effects from Radiation Exposure
Exploration Medical Capabilities
Chapter 8 - Risk of Inability to Adequately Treat an Ill or Injured Crew Member
Space Human Factors and Habitability
Chapter 9 - Risk of Error Due to Inadequate Information
Chapter 10 - Risk of Reduced Safety and Efficiency Due to Inadequately Designed Vehicle
Environment, Tools, or Equipment
Chapter 11 - Risk of Error Due to Poor Task Design
Chapter 12 - Risk Factor of Inadequate Food System
Chapter 13 - Risk of Adverse Health Effects from Lunar Dust Exposure
Exercise and Extravehicular Activity
Chapter 14 - Risk of Compromised EVA Performance and Crew Health Due to Inadequate EVA Suit Systems
Chapter 15 - Risk of Operational Impact of Prolonged Daily Required Exercise
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Human Health and Performance Risks of Space Exploration Missions
Evidence reviewed by the NASA Human Research Program
NASA SP-2009-3405
Edited by:
Jancy C. McPhee, Ph.D., Associate Program Scientist
John B. Charles, Ph.D., Program Scientist
National Aeronautics and Space Administration * Lyndon B. Johnson Space Center * Houston, Texas 77058
Other Contributors
We would like to acknowledge the following for their review of many versions of book chapters: Craig Kundrot, Lisa Stephenson, Ron White, Michelle Edwards, Wilma Anton, Maneesh Arya, Susan Steinberg-Wright, Edna Fiedler, Marcelo Vazquez, Mary Anne Frey, and Victor Schneider. We also appreciate the editing assistance that was provided by Jane Krauhs, Carrie Gilder, and Eileen Nicholas and the valuable peer review that was provided by the Institute of Medicine in spring 2008, which was under the direction of Daniel Masys and Kathy Livermore, as sponsored by Richard Williams, NASA Chief Health and Medical Officer. Lastly, we would like to thank Dennis Grounds, the Human Research Program Manager, for making the capture of the risk evidence a priority and for supporting the effort that was required by the authors to write (and rewrite) these challenging chapters.
Introduction
The Human Research Program (HRP), which is within the NASA Exploration Systems Mission Directorate, is a directed and applied research program that addresses agency needs for human health and performance risk mitigation strategies in support of space exploration as described in the Vision for Space Exploration (1), the U.S. National Space Policy (2), and the NASA Strategic Plan (3). These exploration undertakings include missions to the moon and Mars. Although all of them will involve some of the same human health and performance challenges, each mission also will include specific challenges that depend on the nature of the exact undertaking and the development schedule. Accordingly, HRP research and technology development are focused on the highest-priority risks to crew health and safety, with the goal of ensuring mission success and maintaining long-term crew health.
Three core documents describe the HRP. The first is the Program Requirements Document (PRD)4, which defines, documents, and allocates high-level requirements to different organizational arms of the program; these requirements include responsibility for specific human system risks listed in the PRD. Previously, the Bioastronautics Roadmap (5) documented the health and performance risks and areas of concerns of a wide cross-section of the professional space life sciences community, but it did not have the level of detail that is necessary to prioritize risks across physiological disciplines or to compare strategies for how to manage a given risk across mission operational architectures. The HRP 2009 PRD risk list thus identifies a narrowed and more operationally-focused series of risks.
The second HRP document is the Integrated Research Plan (6) (IRP), which describes what implementation activities are necessary to fill the knowledge and mitigation gaps that are associated with each risk that is listed in the PRD. It also details when those activities will be accomplished, where they will be accomplished (e.g., the International Space Station (ISS) or a ground analog), who will accomplish them (investigators within a specific project or organization within the HRP), and what is being produced (risk uncertainty reduction, candidate health or performance standard, countermeasure strategy, etc.).
The third HRP document is the Evidence Book (7), which is a collection of evidence-based risk reports and journal articles for each individual risk that is contained within the HRP PRD and for which implementation activities are listed in the Integrated Research Plan. Thus, the collection provides the current state of knowledge for each of the defined human health and performance risks for future NASA exploration missions. All three of these documents, which are updated as evidence or events dictate, provide relevant information that can be used to manage the HRP.
The initial 2008 Evidence Book was a collection of written evidence reports that was created from both published and unpublished information reviewed by the HRP in 2006. From April to August 2008, the 2008 Evidence Book was reviewed by members of the Committee on NASA's Research on Human Health Risks, established by the Institute of Medicine (IOM), which is the arm of the U.S. National Academy of Sciences that is charged with examining public health policy. The resulting thorough Review of NASA's Human Research Program Evidence Books: A Letter Report (2008) provides guidance for both a revision of the current risk reports and for the development of future versions. It is publicly available via the National Academies Press Website.8
1 - See http://www.nasa.gov/missions/solarsystem/explore main old.html.
2 - See http://www.ostp.gov/galleries/press release files/Unclassified%20National%20Space%20Policy%20—%20FINAL.pdf.
3 - See http://nodis3.gsfc.nasa.gov/npg img/N PD 1001 000 /N PD 1001 000 .pdf.
4 - See http://humanresearch.jsc.nasa.gov/files/hrp-47052 revc PRD.pdf.
5 - See http://bioastroroadmap.nasa.gov/index.jsp.
6 - See http://humanresearch.jsc.nasa.gov/files/hrp-47065 reva IRP.pdf.
7 - See http://humanresearch. jsc.nasa. gov/elements/smo/hrp evidence book. asp.
8 - See http://books.nap.edu/openbook.php7record id=12261.
The IOM strongly recommended that the 2008 and future Evidence Book risk report information be made publicly available. For more than half of the HRP risk reports, therefore, single reports were revised to incorporate as much as possible the recommendations from the IOM Review and are presented as a collection in this NASA Special Publication, Human Health and Performance Risks of Space Exploration Missions; these reports are also available on the HRP Evidence Book Website. For the remaining risks, report information is currently being revised and reviewed as per the specifications of the specialized, subject-specific journals in which the authors have requested to publish the work. Citations for these journal publications, as they become available, will also be listed on the HRP Evidence Book Website. In the future, updated risk report information for all of the HRP risks will be maintained on the HRP Evidence Book Website in an electronic and rapidly updatable text format.
To help characterize the kind of evidence that is provided in each of the risk reports in this book, the authors were encouraged to label the evidence that they provided according to the "NASA Categories of Evidence."
• Category I data are based on at least one randomized controlled trial.
• Category II data are based on at least one controlled study without randomization, including cohort, case-controlled or subject operating as own control.
• Category III data are non-experimental observations or comparative, correlation and case, or case-series studies.
• Category IV data are expert committee reports or opinions of respected authorities that are based on clinical experiences, bench research, or "first principles."
The NASA categories are comparable to more familiar versions of Levels of Evidence scales (e.g., Silagy C, Haines A. Evidence Based Practice in Primary Care, 2nd Ed., London: BMJ Books, 2001). The use of a coordinated data categorization system is new to many NASA life scientists, but authors were encouraged to use such a system to help clarify the type of evidence that was presented and thus provide additional information about the strength of interpretations that were derived from those data; however, scientists were not required to use the categorization system hierarchically if they determined that this system would obscure or otherwise interfere with the clarity of the evidence that they were presenting.
The HRP, which recognizes the limitations of the distribution of the current risk report information, is evaluating even more thorough distribution possibilities for future editions of the risk evidence information. Through these initial actions, however, the HRP has made a good-faith attempt to fulfill the recommendation of the IOM and the requirement in the Space Act of 1958 (as amended) to disseminate to the widest possible audience the knowledge that is acquired during the course of NASA publicly funded activities.
Jancy C. McPhee and John B. Charles
May 2009
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Behavioral Health and Performance
Risk of Behavioral and Psychiatric Conditions
Risk of Performance Errors due to Poor Team Cohesion and Performance, Inadequate Selection/Team Composition, Inadequate Training, and Poor Psychosocial Adaptation
Risk of Performance Errors due to Sleep Loss, Circadian Desynchronization, Fatigue, and Work Overload
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Risk of Behavioral and Psychiatric Conditions
Kelley J. Slack - Wyle Integrated Science and Engineering Group
Camille Shea - Universities Space Research Association
Lauren B. Leveton - NASA Johnson Space Center
Alexandra M. Whitmire - Wyle Integrated Science and Engineering Group
Lacey L. Schmidt - Wyle Integrated Science and Engineering Group
Behavioral issues are inevitable among groups of people, no matter how well selected and trained. Spaceflight demands can heighten these issues. The Institute of Medicine [(IOM)] report, Safe Passage [Ball & Evans (eds.), 2001], notes that Earth analog studies show an incidence rate of behavioral problems ranging from 3-13 percent per person per year. The report transposes these figures to 6-7 person crews on a 3-year mission to determine that there is a significant likelihood of behavioral conditions and psychiatric disorders emerging. Impacts of behavioral issues are minimized if they are identified and addressed early. The HRP must provide the best measures and tools to monitor and assess mood and to predict risk for and management of behavioral and psychiatric conditions prior, during and following spaceflight. - Human Research Program Requirements Document, HRP-47052, Rev. C, dated Jan 2009.
Human Health and Performance Risks of Space Exploration Missions Chapter 1
Executive Summary
Space flight, whether of long or short duration, occurs in an extreme environment that has unique stressors. Even with excellent selection methods, behavioral problems among space flight crews remain a threat to mission success. Assessment of factors that are related to behavioral health can help minimize the chances of distress and, thus, reduce the likelihood of behavioral conditions and psychiatric disorders arising within a crew. Similarly, countermeasures that focus on prevention and treatment can mitigate the behavioral conditions and psychiatric disorders that, should they arise, would impact mission success.
Risk, which within the context of this report is assessed with respect to behavioral health, is addressed in terms of occurrence in space flight and analog populations, and of predictors and other contributing factors. Based on space flight and analog evidence, the average incidence rate of an adverse behavioral health event occurring during a space mission is relatively low. While mood and anxiety disturbances have occurred, no behavioral emergencies have been reported to date in space flight. Anecdotal and empirical evidence indicates that the likelihood of a behavioral condition or psychiatric disorder occurring increases with the length of a mission. Further, while behavioral conditions or psychiatric disorders might not immediately and directly threaten mission success, such conditions can, and do, adversely impact individual and crew health, welfare, and performance, thus indirectly affecting mission success.
Identification of predictors and other factors that can contribute to the risk of behavioral conditions and psychiatric disorders at all stages of a mission increases the efficacy of prevention and the treatment of those conditions. Many factors predict or otherwise play a role in the occurrence of a behavioral condition or psychiatric disorder. These include: sleep and circadian disruption, personality, negative emotions, physiological changes that occur when adapting to microgravity, lack of autonomy, daily personal irritants, physical conditions of life in space, workload, fatigue, monotony, cultural and organizational factors, family and interpersonal issues, and environmental factors. Positive or salutary aspects of space flight also contribute to behavioral health outcomes. Some factors have both detrimental and salutary aspects; teamwork, giving and receiving social support, and leadership responsibilities are a few examples of these.
The current approaches to prevent behavioral conditions and psychiatric disorders begin during selection and continue post-flight. The goal of the behavioral health component of the astronaut selection system is to identify individuals who, at the time of application, have diagnoses that are incompatible with the demands of space flight, and also to identify those who are believed to be best suited psychologically to be astronauts. Countermeasures are a second line of defense to prevent behavioral conditions and psychiatric disorders from occurring pre-flight, during flight, and post-flight. For example, psychological support services are provided to crew members and their families before, during, and after missions.
Approaches that prevent or mitigate behavioral conditions and psychiatric disorders often can be used to treat the occurrence of behavioral problems. Private psychological conferences, for example, can provide both prevention and treatment. While anecdotal evidence suggests that current practices may be sufficient, the efficacy of these practices has not yet been assessed systematically.
In sum, evidence indicates that development of behavioral conditions and psychiatric disorders is a risk for human space flight, and that this risk increases as mission length increases. Multiple methods are employed to prevent and treat behavioral problems and appear to have some effect, although the extent to which prevention and treatment are effective has not been quantified.
Introduction
The NASA commitment to long-duration space flight includes astronauts who will be returning to the moon as well as those who will take part in human missions to Mars. Successful exploration will require a better understanding of the effects that extended missions pose for the behavioral health of astronauts, not just during flight but also pre- and post-flight. As space flight missions lengthen, astronauts will spend longer periods away from families and friends. The absence of Earthly conveniences and daily routines will also intensify their feelings of isolation (Ball and Evans, 2001) (Category III9) because the astronauts will be spending more time confined in the spacecraft and living in an environment that is fraught with potential danger. On their return to Earth, they will have to reintegrate into a world that has adapted and changed without them. Consequently, predicting the effect that extended periods of isolation will have on astronaut performance and psychological well-being becomes increasingly important (Kanas and Manzey, 2008). Further, the potential for psychiatric disorders developing in long-duration crews during or after missions requires that consideration be given to prevention and treatment (Kanas and Manzey, 2003; Palinkas, 1986) (Category IV).
During astronaut selection, applicants who have been identified with a psychiatric disorder that would impede on-the-job success are removed from further consideration. However, important aspects of an individual's mental health history - e.g., exposure to a traumatic event, family history of mental health struggles such as depression or schizophrenia - may not have been disclosed to NASA at the time of astronaut selection. Not only may potential astronauts be hesitant to share information that would prohibit selection, but some current astronauts have also demonstrated a reluctance to share information if they perceive such information could jeopardize their flight status.
Disorders such as anxiety, post-traumatic stress, sleep loss/insomnia, adjustment, and depression can also develop unexpectedly in otherwise healthy individuals. A recent study by Tozzi et al. (2008) indicates that the average age of onset of depression for persons who have no family history of depression is 41 years (standard deviation (SD)=13.67); therefore, even astronauts who have never experienced depression are not immune from its development. The age of astronaut candidates when selected for the Astronaut Corps has ranged between 26 and 46 years (NASA, 2008b). Between 1989 and 2003, the average age of the astronauts who were selected was 36.5 years. It is important to note that depression could occur at any phase of an astronaut's career. Furthermore, as reviewed by Collins (1985), behavioral problems that occur during space flight often do not terminate when the mission ends, but can linger with notable aftereffects (Category IV).
Although the incidence of reported psychiatric disorders on shuttle missions has not been significant (Billica, 2000) (Category III), as the length of space missions increases the incidence of behavioral conditions and psychiatric disorders is also expected to increase (Ball and Evans, 2001; Otto, 2007; Stuster, 2008) (Category IV). Additionally, the ramifications of a disorder developing in flight are severe if that disorder is left unresolved. Anecdotal and empirical evidence from space flight and behavioral health incidence rates from space analogs suggest that assessing, preventing, and treating behavioral health problems are essential to protecting the health of crew members and, consequently, the success of a mission.
The NASA Human Research Program (HRP) is organized into topical areas called Elements; the Behavioral Health and Performance (BHP) Element is tasked with the responsibility of managing three risks: (1) risk of performance errors due to sleep loss, circadian desynchronization, fatigue, and work overload; (2) risk of performance errors due to poor team cohesion and performance, inadequate selection/team composition, inadequate training, and poor psychosocial adaptation; and (3) risk of behavioral and psychiatric conditions. While each of these risks is addressed in a separate chapter of this book, they should not be construed to exist independently of one another but, rather, should be evaluated in conjunction with one another. Furthermore, BHP risks overlap with risks in other HRP Elements and, as such, must also be considered in conjunction with one another. Refer to figure 1-1 for an example of these possible overlaps.
The relationships of the BHP Element with other HRP Elements are further outlined in the HRP Integrated Research Plan (IRP)10. The nature of the IRP implies that the BHP Element is continually reviewing and updating integration points with other elements. While research is designed to address identified gaps, it will be necessary to update and revise each of the BHP evidence reports and the IRP as the element gaps are closed and new gaps emerge.
10 - See http://humanresearch.jsc.nasa.gov/about.asp.
Evidence
Assessment of behavioral conditions and psychiatric disorders
An assessment of behavioral conditions and psychiatric disorders improves our understanding of the factors that contribute to the development of these conditions, and the treatment options that are best to manage this risk. Assessments occur within a framework, or a theoretical approach, of assessing behavioral conditions and psychiatric disorders. This theoretical approach, which is taught by NASA BHP to astronauts and flight surgeons, is described below. Evidence of the occurrence of behavioral and psychiatric problems in space flight and space analogs is then presented. Predictors and other factors that contribute to the occurrence of a behavioral condition and psychiatric disorder are then discussed. Lastly, current countermeasures and treatments are described.
The majority of the evidence that is cited is Category III. Please note that from this point on, only categories other than Category III are noted within the text.
Theoretical approach
Behavioral and psychiatric problems can be classified in several ways. NASA relies heavily on the classification system that is used by the American Psychiatric Association (APA) in the Diagnostic and Statistical Manual Fourth Edition Text Revision (DSM-IV-TR) (APA, 2000). In a slight departure from the DSM-IV-TR classifications, behavioral medicine training that is taught by a NASA psychiatrist also incorporates the International Classification of Diseases-10 (ICD-10) (World Health Organization (WHO), 1996) standard diagnostic classification system. The ICD-10, which is used worldwide, is a more comprehensive system than the DSM-IV-TR; it is used to classify physical and mental diseases as well as conditions for all general epidemiological and many health management purposes. Mental and Behavioural Disorders is only one chapter in this much broader tome. In contrast, the DSM-IV-TR, which focuses on mental and behavioral disorders, assigns the following classifications:
• Axis I - clinical disorders
• Axis II - personality disorders and mental retardation
• Axis III - general medical conditions
• Axis IV - psychosocial and environmental problems
• Axis V - global assessment of functioning
When using the DSM-IV-TR, general medical conditions, psychosocial and environmental problems, and global assessment of functioning are relevant only to the extent that they contribute to or exacerbate psychiatric diagnoses.
Behavioral medicine training for the International Space Station (ISS) teaches NASA flight surgeons, crew medical officers (CMOs), and astronauts that there are three main types of significant mental disorders that might be encountered in a long-duration mission (NASA, 2008a): (1) delirium, which is a severe behavioral and cognitive response to physical injury or illness; (2) adjustment disorder, which is a severe and negative emotional response to a tragedy; and (3) asthenia, which is a progressive negative psychological response to the isolation and rigors of a long-duration mission. The Russian Space Agency, even more so than NASA, recognizes asthenia as a condition that occurs during long-duration missions (Kanas, 1991). NASA behavioral medical training also instructs astronauts to be vigilant for other possible psychiatric or behavioral conditions. These other conditions fall under the rubric of any other psychiatric disorders, which is the first indication of a preexisting or latent mental disorder that is, perhaps, worsened or triggered by the stress of long-duration space flight.
Occurrences of behavioral conditions and psychiatric disorders
NASA differentiates between a behavioral condition and a psychiatric disorder in the following manner: a behavioral condition is any decrement in mood, cognition, morale, or interpersonal interaction that adversely affects operational readiness or performance; whereas a psychiatric disorder is one that meets the diagnoses criteria as outlined in the DSM-IV-TR. In other words, a behavioral condition is a sub-clinical, off-nominal set of behavioral and psychological circumstances or symptoms that, if left unchecked or unmitigated, may lead to the development of a psychiatric disorder that will, at that time, be considered an illness that requires a specific medical and psychiatric treatment plan. In the future, the title of the risk that is described in this chapter is expected to change to more clearly reflect these distinct definitions.
Space Flight
The flight surgeon is usually the confidant if, and when, an astronaut reports behavioral signs and symptoms. Thirty-four behavioral signs and symptoms were reported among the 208 crew members who flew on 89 shuttle missions between 1981 and 1989, spending a total of 4,442.8 person-days in space. This is an incidence rate of 0.11 for a 14-day mission; in other words, behavioral signs and symptoms, regardless of the type of sign or symptom, occurred at the rate of approximately one per every 2.86 person-year (Billica, 2000). The behavioral symptoms that were most commonly reported in these 89 missions were anxiety and annoyance (Billica, 2000). Between March 1995 and June 1998, seven astronauts flew on the Russian space station Mir; during this time, psychiatric events were reported twice for an incidence rate for astronauts of 0.77 per person-year (Marshburn, 2000). The actual incidence rate for both shuttle and Mir is likely to be understated, however, because of astronaut reluctance to report such symptoms (Ball and Evans, 2001; Shepanek, 2005). The actual reported behavioral events and recurrences can be reviewed in the U.S. Medical Events Tables found in the chapter appendix.
Behavioral and psychiatric emergencies
NASA considers any behavioral condition or psychiatric disorder that causes serious behavioral or cognitive symptoms leading to incapacitation and severe mission impact as a behavioral emergency. Examples include the development of delirium due to a head injury, or a brief psychotic disorder following a tragic event such as the death of a family member or an international catastrophe. To date, no behavioral emergencies have occurred before or during any U.S. space flight. As previously mentioned, however, as the length of space missions increases, the probability of a behavioral and psychiatric emergency occurring also increases (Ball and Evans, 2001; Stuster, 2008) (Category IV).
Not a lot of data are available from which to assess the many types of behavioral conditions and psychiatric disorders that could occur during a long-duration mission. This is due, in part, to the relatively few numbers of long-duration flyers, and to the fact that the consistent length of a mission for most of these flyers is approximately 6 months. Based on past NASA experience, one estimate of the possible rate of a behavioral or a psychiatric emergency occurring in flight as the result of depression or anxiety ranges from 0.000087 to 0.000324 cases per person-year (NASA, 2007b). The likelihood of such an emergency occurring would further increase as mission length exceeds 1 year. Calculation of this estimate, which is based on NASA space flight data, is discussed more fully in the Mood and Mood Disorders section below.
Some Russian space flight missions in the 1970s and 1980s were terminated early due to psychological factors (Cooper, 1976). In 1976, during the Soyuz- 21 mission to the Salyut-5 space station, the crew was brought home early after the cosmonauts complained of a pungent odor. No source for this odor was ever found, nor did other crews smell it. Since the crew had not been getting along, the odor may have been a hallucination. In 1985, the crew of the Soyuz T-14 mission to Salyut-7 was brought home after 65 days because cosmonaut Vladimir Vasyutin complained that he had a prostate infection (Clark, 2007). Doctors later believed that the problem was partly psychological. The Soyuz TM-2 mission in 1987 was similarly cut short because of some apparent psychosocial factors (Clark, 2007). The early termination of these missions may have prevented escalation of behavioral and psychiatric occurrences.
The stress of space flight does not end at landing. In early 2007, an astronaut who had recently returned from a space mission allegedly engaged in actions that might be considered indicative of a behavioral and psychiatric emergency (c.f., Editorial, 2007). Space flight is not necessarily the sole or even the primary cause of post-flight behavioral conditions and psychiatric disorders. Other stressors in life, such as marital distress (Aldrin, 1973; Kanas, 1987) or the death of a family member (Clark, 2007), also may contribute to similar behavioral conditions and psychiatric disorders. Nevertheless, space flight and its associated factors - e.g., isolation, confinement, workload - can become significant triggers or sources of stress. These space flight stressors, when they are paired with traditional life stressors, will likely have an exponential impact on behavioral health for long-duration astronauts (Kanas and Manzey, 2008).
Mood and mood disorders
Mood states can be dichotomized into positive and negative moods (Watson and Tellegen, 1985). Positive moods have been linked to increased helping behavior toward others (e.g., Fisher, 2002; George, 1991; Isen and Levin, 1972). A positive mood may result in better performance through interpersonal processes such as helping others (Tsai et al., 2007). Further, employees in positive moods may perform better through a motivational process such as higher self-efficacy and task persistence (Tsai et al., 2007). George and Brief (1996) found that people who were in positive moods were more likely to view their progress toward task goals positively and engage in increased task diligence.
Like positive moods, negative moods can be functional. They can cause individuals to better identify problems by focusing on their current situation rather than on their underlying assumptions, attending to shortfalls in the status quo, identifying opportunities, and exerting high levels of effort to improve a situation (George and Zhou, 2002; George and Zhou, 2007; Kaufmann, 2003; Martin and Stoner, 1996; Schwarz, 2002; Schwarz and Skurnik, 2003). Additionally, negative moods promote creativity under certain conditions (e.g., Gasper, 2003; George and Zhou, 2002; Kaufmann, 2003; Kaufmann and Vosburg, 1997), which can facilitate problem-solving.
The effects of positive mood are discussed in later sections of this chapter and address salutogenesis in space flight and analogs, respectively. Space-flight-related research, albeit quite limited, has focused on the displacement of negative mood from crew members to Mission Control personnel, and from Mission Control personnel to management (Kanas, 2005; Kanas et al., 2007).
Mood disorders, which are categorized in the NASA integrated medical model (IMM) as depression and anxiety, have occurred during space flight. Data that were collected for 28.84 person-years of NASA space flight reveal that 24 cases of anxiety occurred in space flight for an incidence rate of .832 cases per person-year (NASA, 2007a). Over the same 28.84 person-years, four astronauts experienced signs and symptoms of depression during space flight for an incidence rate of .139 per person-year (NASA, 2007a). In other words, signs and symptoms of anxiety during space flight occurred once every 1.2 years, and signs and symptoms of depression occurred once every 7.2 years.
According to a National Institute of Mental Health (NIMH) (1999) pamphlet (Category III), approximately one in 10 adults during a given year will suffer from some form of depression. Despite careful selection, a depression-free past does not guarantee a depression-free future.
The data that were collected in the general population as well as in NASA are not definitive enough at this time to accurately predict the likelihood of an astronaut becoming depressed or suffering from a mood disorder while in flight. Rather, it emphasizes that the risk is real and should not be ignored. Therefore, NASA is continuing to gather the data that are needed to define and mitigate the risk of an astronaut developing an anxiety or a depressive disorder.
Asthenia
Russian medical personnel view asthenia as one of the greatest problems affecting the emotional well-being of cosmonauts (Kanas, 1991). This syndrome, which is also called neurasthenia and asthenization, has been defined as "a nervous or mental weakness manifesting itself in tiredness. and quick loss of strength, low sensation threshold, extremely unstable moods, and sleep disturbance" (Kanas and Manzey, 2003, p. 115). It can be caused by excessive mental or physical strain, prolonged negative emotional experience or conflict, as well as somatic illness (Petrosvsky and Yaroshevsky, 1987). The diagnostic criteria for asthenia and neurasthenia are listed in the ICD-10 (WHO, 1996). However, this diagnosis is not recognized in the DSM-IV-TR (APA, 2000). Other diagnoses with similar symptoms that are listed in DSM-IV-TR are adjustment disorder, dysthymia, major depressive disorder, and chronic fatigue syndrome.
Examination of cosmonauts suggests that asthenia is particularly likely to occur when space flights last longer than 4 months (Myasnikov and Zamaletdinov, 1996). Symptoms and signs of asthenia have been reported anecdotally by U.S. astronauts who flew during Mir and Skylab (Burrough, 1998; Freeman, 2000; Harris, 1996). Kanas et al. (2001), however, failed to find empirical support for the occurrence of asthenia during Mir missions. This failure to find support could be due to the method that was used to operationalize asthenia. Only the psychological component of asthenia was examined; furthermore, the study used an instrument that was not specifically designed to measure asthenia.
At present, the occurrence of asthenia in space flight crews does not require medications; this may be due in part to the current space flight parameters (e.g., length of flight, contact with the ground, Progress and shuttle flights, etc.). Furthermore, this is likely due in part to stringent selection methods that select out those with psychiatric problems, and to diligent monitoring and application of countermeasures when symptoms first appear (Myasnikov et al., 2000, as cited in Kanas et al., 2001). Longer-duration missions may demonstrate a need for asthenia medications.
Psychosomatic reactions
Psychosomatic reactions occasionally have been reported during space flight. Psychosomatic is defined as "pertaining to a physical disorder that is caused by or notably influenced by emotional factors" (Dictionary, 2008). These health struggles are not imaginary; in fact, more than half of all individuals who are seeking medical attention are suffering from psychosomatically induced or exacerbated illnesses (Goldensen, 1970; Birley, 1977; Fava and Sonino, 2000). For example, an otherwise healthy cosmonaut experienced a cardiac arrhythmia that required medication after being exposed to sustained stressors related to on-board equipment failure (Carpenter, 1997; Cowings et al., 2000; Kornilova et al., 1998, 2000).
There are direct self-reports of somatizing by cosmonaut Valentin Lebedev during the record-breaking length of his Salyut 7 mission. Other psychosomatic reactions include complaints of toothaches after dreams of tooth infections (Chaikin, 1985) and fears of impotence due to perceived prostatitis (Harris, 1996).
Salutogenesis
Not all of the effects of long-duration space flight are expected to be negative. Antonovsky, in 1979 (Category IV), coined "salutogenesis" as the opposite of pathogenesis. Salutogenic experiences are those that promote a sense of health. The key factor of salutogenesis, according to Antonovsky (1979), is a person's sense of coherence. He defined this sense of coherence as "a global orientation that expresses the extent to which one has a pervasive, enduring though dynamic feeling of confidence that one's internal and external environments are predictable and that there is a high probability that things will work out as well as can reasonably be expected." Kobasa et al. (1979) described individuals who stay healthy, even when they find themselves in challenging circumstances, as having the following characteristics: believing that they exert control over their environment; embracing life as meaningful; and experiencing changes in life as normal and beneficial. Factors contributing to salutogenesis are comprehensibility, manageability, meaningfulness, social support, spirituality, happiness, humor, and love (Kent, 2002; Smith, 2002). Smith (2002) commented that "an organism with a salutogenic brain would experience the world as manageable and coherent . with a self-perpetuating cycle for enhancing self-confidence and well-being."
Suedfeld (2005) differentiates between positive environmental aspects and the positive personal and social aspects of space flight. Environmental aspects concern the external environment (e.g., mystery; beauty of space; views of Earth) and the capsule environment (e.g., safe haven; familiarity; free time). The positive personal and social aspects of space flight were likewise dichotomized into astronaut group dynamics (e.g., membership in an elite group; superordinate goals) and post-mission consequences (e.g., self-confidence; respect; new skills and values).
Preliminary results suggest that a salutogenic response to space flight is common across astronauts and endures for some time post-flight. Astronauts and cosmonauts have reported experiencing transcendental, religious experiences or a sense of the unity of humankind while in space (Connors et al., 1985; Ihle et al., 2006; Kanas, 1990). Analysis of the memoirs of four astronauts reveals that all four reported post-flight feelings of increased spirituality, defined as "meaning and inner harmony through transcendence" (Suedfeld and Weiszbeck, 2004, p. C7). Ihle et al. (2006) examined the positive psychological outcomes of space flight. All 39 astronauts and cosmonauts who responded to the survey reported a positive reaction to being in space. The most frequently endorsed benefit of space flight related to the perception of the Earth; i.e., its beauty and fragility. Analysis of photographic images taken from ISS during Expeditions 4 through 11 indicates that most images taken by crew members were self-initiated (84.5% of 144,180 photographs) and that photography was considered a leisure activity (Robinson et al., in press). During missions to Mars, however, the Earth will not always be visible. The effects of not being able to see Earth could have a detrimental effect on the psychological well-being of crew members (Kanas and Manzey, 2003; 2008).
Psychosocial adaptation and disorders
Anecdotal evidence from crew members illuminates the distress that some individuals encounter during long-duration space flight missions. Psychosocial adjustment is, by definition, the psychological and social process of adapting or conforming to new conditions (Merriam-Webster, 2008). Unsuccessful psychosocial adaptation can lead to adjustment disorders that are characterized by decrements in performance (APA, 2000).
In-flight diaries of cosmonauts and astronauts recount periods of psychological distress experienced during extended periods in space (Ball and Evans, 2001). Even crew members with otherwise cheerful dispositions may demonstrate changes in temperament when meeting the challenges of space flight adaptation. Lebedev wrote in his journal, "[M]y nerves were always on edge, I get jumpy at any minor irritation" (Lebedev, 1988, p. 291). One astronaut described his inability to fully prepare for long-duration space flight challenges, "I was astounded at how much I had underestimated the strain of living cut off from the world in an otherworldly environment" (Linenger, 2000, p. 151).
Ineffective adjustment to life in space can take many forms. Withdrawal from fellow crew members or ground support crew is one form of ineffective adjustment. Discord or tense relations with fellow crew members is another form of ineffective adjustment.
A third form of ineffective adjustment is deviant behavior. One expert of isolated and confined environments has identified two categories of deviant behavior in U.S. Antarctic winter-over crews: (1) individuals who fail to conform to group norms/expectations; and (2) individuals who act as the station class jester, whose behavior is outside of the mainstream yet not outrageously disruptive or threatening (Palinkas, 1989, 1992). Deviant types of behavior in space may fall into these same two categories. For example, Lebedev admitted that he disregarded safety procedures when he became frustrated. In his haste to access new letters from home, he did not wear safety goggles because "they fogged up, but if metal dust had entered my eye the flight would have ended" (Lebedev, 1988, p. 304). Illustrating the second category of deviant behavior is Linenger's coping behavior: "I also made my own diversions . Playing the space version of 'sneaking up' . Flying silently down the length of a module, I would approach one of my crewmates and, still undetected by him, move very close. I would then hover patiently until he turned around. I knew that I had gotten him whenever he would gasp and flail his arms backward" (Linenger, 2000, p. 159). Anecdotal evidence from space flight suggests that astronauts and cosmonauts at times engage in disruptive coping behaviors that could presage larger behavioral issues.