Issues Magazine

The Psychology of a Voyage to Mars

By Adelma M. Hills

A crewed mission to Mars is expected to occur before the middle of this century, but we must not underestimate the challenges involved, not to mention the enormous cost.

Significant engineering challenges will face a voyage to Mars and back, as beyond the thin shield of the Earth’s atmosphere we enter a realm entirely hostile to human survival. Anyone venturing into that realm must take everything they need, including a robust habitat that provides protection from all the hazards that exist; a propulsion system; and all their air, water, food and medical supplies. If this isn’t challenge enough, ways must also be found to deal with the many physical effects of space flight, especially those due to the lack of gravity.

Another, often overlooked, dimension is the psychological one. A journey to Mars will take people very far from Earth for an extended period of time. A one-way trip takes around nine months, a round trip up to two years or more depending on length of stay. How will people fare on such a journey?

In many ways, the first expeditions to Mars will be on a par with the first ocean voyages, when people set off into the unknown for months and years, cut off from all communication with home, and beyond the reach of help should anything go seriously wrong. At the same time the voyage to Mars will be unlike anything humans have ever experienced before, with effects and consequences we cannot entirely foresee, no matter how well we try to prepare.

Preparations have, in fact, been underway for many years, and much of the research has taken place in isolated, confined, extreme (ICE) environments on Earth, notably Antarctic base stations and submarines, as well as the space capsule habitats themselves (e.g. the Space Shuttle, the Russian MIR Space Station, and now the International Space Station).

ICE and capsule environments are not for the faint-hearted. They pose a much greater risk to human survival than most of us ever face in our more conventional environments. First and foremost there is an ever-present and very real element of danger, where survival utterly depends on the integrity of the life-support system. In space, additional risks include exposure to high-energy radiation and impacts by meteorites or asteroid particles, as well as the possibility of critical systems failure, loss of oxygen or contamination of the air supply, or fire in a confined space. These are sources of unavoidable and chronic background stress, so spacefarers must not be prone to anxiety.

The microgravity of space habitats presents unique problems for body physiology and chemistry, such as loss of bone density and weakening of muscles including the heart. At least two hours of exercise every day is essential to maintain fitness ( Hygiene is also an issue in microgravity, because any particles (food, drink, bodily fluids) that escape simply float around until captured. “Long-duration space capsules can become disgustingly unsanitary,” say Peter Suedfeld and G. Daniel Steel in their paper on the environmental psychology of capsule environments (Annual Review of Psychology 2000, 51, 227–53). Although these are physical factors, they have significant implications for psychological well-being, especially on long duration missions.

Another well-documented physical source of psychological stress is noise, and it can be a salient stressor in space environments. Associated with vibration from machinery and equipment, monotonous and constant noise can not only interfere with concentration and sleep, but also be an ongoing source of irritation, all the more so when crew members are monitoring the background noise for any changes that could indicate mechanical failures or outside threats.

The loss of the normal day–night cycles in capsule environments can disrupt time perception, sleep patterns, and the body’s “internal clock”, the 24-hour circadian rhythms in alertness and concentration, blood pressure and hormone levels. This necessitates careful attention to job rotation patterns and work–rest cycles. Effective rest, exercise and recreation periods need to be interspersed with work schedules to maintain health, well-being and work performance, but these can be difficult to achieve in a capsule environment.

In the weightless conditions of space habitats, crew members must be attached to something when sleeping to avoid floating around and bumping into things. Recreational options are limited and there are none of life’s luxuries to help deal with stress. There’s no going out for a restaurant meal, no fresh food, and no luxurious 10-minute showers. Water, including from bodily waste, needs to be recycled, as does the air the crew breathes, which must be “scrubbed clean” to remove carbon dioxide and other contaminants in the process.

Some of these features are not unique to the space context, but an absolutely new challenge for those people who travel to Mars will be the experience of a profound isolation and separation from the Earth. Isolation in any context can have adverse psychological effects, including drowsiness and sleep disorders, depression, and even neurotic stress responses or suicidal or psychotic thinking.

There may be significant effects on the journey to Mars when, for the first time in the history of our species, people will experience a complete disconnection from the Earth. Even communication with Earth will be impossible in real time, with an ever-increasing delay to as much as 20 minutes. Earth will slowly become just a bright dot in the blackness of space. What might that feel like, and what might be its psychological effect on individual crew members?

Imagine looking up from the surface of Mars knowing that the little blue dot in the sky is the Earth – or not being able to see Earth at all. Everyone and everything you know and care about – family, friends, your home, cities, countries, forests, mountains, oceans, animals and plants – is unimaginably far away.

The NASA image of a tiny Sun setting on Mars already conveys something of what it will be like, but how will this compare to the actuality of being there? We simply do not know, but we can be sure that it will affect some people differently to others.

It might come as a surprise that one of the potentially more serious aspects of long duration space missions is monotony. Despite its exciting impression, the reality of space travel for the most part is one of invariant routines, in an unchanging external environment, with a general lack of sensory variation or novelty. Boredom can be the result, leading to various behaviours to counteract it, including the usual harmless ones of listening to music, reading, writing and watching videos. Videos of home may be especially important on long distance missions.

Boredom can also lead to an increasing interest in food, but its most dangerous effect can be a craving for excitement. This can lead to reckless behaviour such as neglect of safety procedures, the consequences of which can easily be fatal in extreme environments. Boredom could also permit crew members to dwell on the reality of being profoundly disconnected from the Earth and the rest of humanity. On long space missions in the future, boredom combined with isolation may be especially dangerous if it leads to altered states of consciousness or more serious dissociated or psychotic states. Even if only one crew member is affected, this will still have serious consequences for the team and the mission.

Both isolation and monotony increase the importance of feelings of connection to the other members of the team, but with this comes the possibility of social monotony. Confined in the company of former strangers, with the impossibility of taking real time-out to get away from people to calm down or deal with conflicts, even minor annoyances such as trivial speech or behavioural habits can produce effects out of all proportion – unbearable irritation, anger and even violence. Crews on the International Space Station include women and men and are multinational as well as multidisciplinary, increasing the likelihood of conflicts due to differences in personal, cultural or professional expectations.

Psychologists have an important role to play in developing effective selection tools to ensure maximum compatibility. The right individuals need to be selected, and the right training needs to be provided, so that all crew members appreciate individual differences, understand group dynamics, are appraised of different cultural norms and expectations, and are provided with a repertoire of coping strategies to optimise teamwork and deal with social tensions and conflicts. All must understand the importance of avoiding long-term animosity. The roles of group members need to be clearly articulated and so well-designed that they support group coherence and function rather than lead to confused expectations, conflicting responsibilities, poor communication or divisive responses.

Selecting the right team involves a raft of procedures, including psychological tests that assess “mood, depression, interpersonal confidence, optimism, anxiety-proneness, coping strategies, self-perceptions, and the Big-Five personality dimensions” (Suedfeld & Steel, 2000). The optimum combination of personality traits is still debated, but of the Big-Five there is agreement that neuroticism should be low; that is, spacefarers need to be emotionally stable. Conscientiousness, which is implicated in task ability, also needs to be high, as does agreeableness, which is related to sociability. The ideal crew member will be unperturbed by minor disagreements and have a high level of tolerance for the annoying characteristics of others.

People chosen for long duration space missions must have these general characteristics and be able to retain them in stressful situations. They must be able to remain task-focused, calm, decisive and quick-thinking, yet still be cooperative when under pressure and in life-threatening emergencies.

The popular idea that an excitement-seeking extrovert would be an ideal space crew member may be false because of the lack of excitement and social stimulation that tends to be the norm in capsule environments. Similarly, being too high on openness to experience (the last of the Big-Five) might also be problematic because it also incorporates a desire for novelty and excitement. “Somewhat reserved ‘sociable introverts’ – who enjoy, but do not need, social interaction – seem optimally suited.” say Suedfeld and Steel. Unfortunately there tends to be a paradox at work: people who volunteer for extreme environments tend to be high on thrill-seeking, competence motivation, personal control and autonomy, none of which are really suitable for long duration space missions.

A great deal of research on social and individual dynamics has been conducted in polar and space environments, and simulated sites on Earth, such as the Mars-105 study in which four volunteers spent 105 days in a simulated space facility in Moscow (Nicolas, M., Sandal, G., Weiss, K. & Yusupova, A. Journal of Environmental Psychology 2013, 35, 52–8).

Ongoing research will be needed in the lead-up to the crewed Mars mission, and that research needs to be multidisciplinary, involving all areas of psychology and the social sciences, as well as the biological and physical sciences and the arts, so that we gain as much understanding as possible (Harris, P.R. 2009, Space Enterprise: Living and Working Offworld in the 21st Century. Praxis Publishing Ltd, Chichester, UK).

What cannot be properly simulated, however, is the reality of that profound separation from Earth that will occur for the very first time on the voyage to Mars.

Some of this paper has been taken or adapted from the author’s iTunes U open-access course on Behaviour and Environment, Module 12: Future environments – Destination outer space.