Psychological and Behavioral Changes during Confinement in a 520-Day Simulated Interplanetary Mission to Mars

Abstract

Behavioral health risks are among the most serious and difficult to mitigate risks of confinement in space craft during long-duration space exploration missions. We report on behavioral and psychological reactions of a multinational crew of 6 healthy males confined in a 550 m3 chamber for 520 days during the first Earth-based, high-fidelity simulated mission to Mars. Rest-activity of crewmembers was objectively measured throughout the mission with wrist-worn actigraphs. Once weekly throughout the mission crewmembers completed the Beck Depression Inventory-II (BDI-II), Profile of Moods State short form (POMS), conflict questionnaire, the Psychomotor Vigilance Test (PVT-B), and series of visual analogue scales on stress and fatigue. We observed substantial inter-individual differences in the behavioral responses of crewmembers to the prolonged mission confinement and isolation. The crewmember with the highest average POMS total mood disturbance score throughout the mission also reported symptoms of depression in 93% of mission weeks, which reached mild-to-moderate levels in >10% of mission weeks. Conflicts with mission control were reported five times more often than conflicts among crewmembers. Two crewmembers who had the highest ratings of stress and physical exhaustion accounted for 85% of the perceived conflicts. One of them developed a persistent sleep onset insomnia with ratings of poor sleep quality, which resulted in chronic partial sleep deprivation, elevated ratings of daytime tiredness, and frequent deficits in behavioral alertness. Sleep-wake timing was altered in two other crewmembers, beginning in the first few months of the mission and persisting throughout. Two crewmembers showed neither behavioral disturbances nor reports of psychological distress during the 17-month period of mission confinement. These results highlight the importance of identifying behavioral, psychological, and biological markers of characteristics that predispose prospective crewmembers to both effective and ineffective behavioral reactions during the confinement of prolonged spaceflight, to inform crew selection, training, and individualized countermeasures.

Value diversity and crew relationships during a simulated space flight to Mars

“…It is noticeable that this change occurred simultaneously as several crew members reported feeling less motivated, more depressed and irritable. An increase in depressive symptoms and psychological distress in the second half of the confinement are consistent with findings by other research groups [28,29]. A progressive decrease in positive emotions was also found during the previous 105-days confinement [30] and during Russian space missions [31].…”

“…Potential bias in under-reporting negative symptoms during the mission has been noted also by other researchers [28]. In this study, this limitation seemed to be particularly linked with responses to part 3 of the PCVQ in which the crew members were asked to indicate tension which they attributed to individual differences in values.…”

“…The 520-days simulation had essential features of an environment that has fidelity to study psychological reactions to long duration space missions [28]. Nonetheless, simulation cannot completely reproduce the living conditions likely to be experienced by astronauts and cosmonauts during interplanetary missions such as the inherent danger, extreme isolation and lack of possibilities to evacuate.…”

Preparation and medical follow-up for a single-handed transatlantic rowing race

“…With the aim of reaching distant planets, it is necessary to gather data on human feelings and mental state in isolated situations. Studies have looked at situations of isolation lasting over a year [15]. Data on mental states in isolation have led to improvement in preparative procedures for scientists, whether sailors or other, before long term isolation on expeditions, boat races or other missions.…”

Gardening for Therapeutic People-Plant Interactions during Long-Duration Space Missions

“…Our species evolved in a natural world, not in an unnatural man-made built environment. A simulated interplanetary mission to Mars study of six men in an analog environment revealed a diversity of behavioral responses (Basner et al, 2014) with some individuals exhibiting very modest changes, and at least one individual with increasingly more severe behavioral health decrement over time. As we evolved in a 1g world, living in a microgravity environment poses physiological and physical health challenges for flight crews that can negatively impact psychological wellbeing such as space motion sickness, shifts in body fluid distribution, and vestibular dysfunction (Williams et al, 2009) (Wilson, 1984), then people have an "innate tendency to focus on life and lifelike processes," and in a broader sense this could be taken to mean we have evolved with an innate need to be in and experience nature.…”