From the beginning of the Space Age physicians, human factors engineers, and psychologists expressed concerns about people’s abilities to meet the physical, psychological, and interpersonal demands of working in space. Today, we have considerable information about human performance in space (Woolford & Mount, 2006; Woolford, Sipes & Fiedler, in press). In this paper we present an introductory discussion of human factors and behavioral health in the context of a Mars mission, and offer brief comments on desiderata for future spaceflight human factors research. In a later paper in this volume we discuss astronaut selection, training, and psychological support.

1. Introduction

At the dawn of the space age the most urgent questions facing human factors experts involved men’s abilities to withstand ballistic and orbital flight and to perform crucial tasks, such as systems monitoring and conducting simple experiments. The transition to extended missions with larger and more diverse crews raised many new questions about astronaut behavior and performance and broadened thinking about the psychology of spaceflight. The traditional "knobs and displays" approach to human factors, rooted in biomechanics, perception, memory and cognition had to be extended to encompass attitudes, emotions, personality, interpersonal and organizational dynamics, and culture (Connors, Harrison & Akins, 1985; Harrison, 2001; Helmreich, 1983). Reflecting an expanded view, NASA has recently completed a new set of standards and a Human Systems Integration Design Handbook to accompany the standards (NASA 2007; NASA 2010).

Early astronauts had the "right stuff" for highly dangerous solo flights. Intelligence, skill, and physical courage still matter, but the definition of the "right stuff" had to be adjusted to meet the demands of later missions. Today, the "right stuff" includes the crew members’ ability to function as a part of a team and get along with one another for prolonged periods of time (Suedfeld, 2005). It is defined in part by behavioral health (Ball & Evans, 2001; Brady, 2005; Harrison, 2005). Beyond an absence of neurological and psychiatric problems, behavioral health implies feeling good about oneself (for example, a sense of accomplishment) and positive, rewarding interactions with the physical environment (such as enjoying the grandeur of space) and social environment (such as a sense of camaraderie with fellow crewmembers). Assuring good behavioral health requires a systems perspective, and addressing issues at the individual, small group, and organizational levels (Harrison, 2005).

2. Space Architecture and Environmental Support

Space architecture is the theory and practice of designing and building environments for humans in outer space (Harrison, 2010; Howe & Sherwood, 2009). This field combines engineering and aesthetics and requires knowledge of orbital mechanics, propulsion, and the psychology of isolated and isolated and confined groups. While seeking solutions for all of the usual architectural problems (areas and volumes, layouts, adjacencies, doors, windows and décor) space architects must reckon with the lethality of the external environment, the high costs of lifting flight-qualified materials into space, and life support systems. Because on a voyage to Mars boredom could become a problem, interesting features such as art presented on an LCD panel could be helpful. Like their predecessors, Mars astronauts will enjoy pictures of Earth, home, family and friends.

Survival depends on the integrity of the spacecraft and reliability of the life support systems. Spacecraft and habitats must be resistant to structural and mechanical failure, in the case of a Mars mission for three years. Work and living areas must be "user friendly" in the sense that they are tolerant of human limits and mistakes. Lay-outs must allow sufficient room for the activities that they are intended to support, and they must be easy for users to comprehend and navigate, even under conditions of microgravity Habitability, or quality of life in space, has improved steadily since the early days and should improve further as we prepare for Mars. Sleeping quarters should be shielded from sound, light, and adjacent activities as spacecraft are both busy and noisy places. Privacy should be available, as well as areas where crew members – including the whole crew - can interact with one another. One of the strongest lessons so far is the value of windows and views of the outside (Robinson, et. al, 2006).

As anyone who has toiled in an overheated, humid, malodorous environment with limited hygienic facilities and barely potable drinking water can attest, good working conditions encourage good work. Life support systems will have to meet human needs both in transit and on Mars, and different systems and configurations may be required for these two settings. Life support systems should operate as integrated wholes, require little service, and be easy to repair when necessary (Boston, 1996). Artificial atmospheres must consist of a carefully chosen mix of gasses, free of contaminants, and set an acceptable pressure to sustain life and power mental and physical activities. Performance suffers under temperature extremes, and comfort depends in part on the right temperature-humidity mix. Other requirements include a continuous supply of clean water and hygienic systems that are easy to use, perform well under conditions of microgravity, and yield acceptable results. Caloric, vitamin and mineral needs differ on Earth and on a trip to Mars food and supplements must stay unspoiled for three years or more. Menus should be varied and appetizing, keeping in mind that a meal uneaten is nutrition lost.

During the flight and on Mars human performance could suffer due to poorly designed equipment and tools, improperly programmed computers, impractical or overly complex procedures, hard to read displays, and cumbersome, insensitive, or confusing controls. It could suffer, also, from extended time periods between skill acquisition and skill utilization, which is why NASA has recommended some "just in time" training during the mission. We expect heavy use of artificial intelligence in the form of decision aids, automated systems, and robotics. Given rapid advancement in these areas it is difficult to anticipate exact contributions from automation and robotics ten or more years from now. These systems should be transparent (in that the crew members understand their operations and can perform "reality checks") and easily adjusted or modified by their operators. Highly reliable automated and robotic systems can reduce risk by undertaking dangerous activities (such as external repairs) and reduce drudgery by handling routine housekeeping tasks.

3. Individual Performance

Like other missions, Mars missions will be characterized by periods of demand for peak physical and mental performance, separated by variable interludes of low activity. We can anticipate when some of the most intense periods of activity will occur (for example, arriving at Mars), but in some cases such as emergencies high demands will appear suddenly and without warning.

Injury and illness, poor hydration or nutrition and many other factors threaten performance anywhere, but the performance effects of microgravity are consequential only in space. Many of the effects of "weightlessness" such as space sickness, frequent urination, and digestion problems will be resolved early in the mission. Other bodily changes offer near-term advantages but have adverse effects later on (Buckey, 2006). Bone demineralization, fluid shifts, cardiovascular deconditioning, and loss of muscle strength are adaptive under conditions of weightlessness but can cause performance decrements following landing. These include difficulty standing and walking, dizziness, physical weakness, and lack of stamina. Countermeasures include vigorous exercise programs, extra fluids, and dietary supplements (Buckey, 2006).

On a space mission, where each additional crew member adds substantially to the cost, it is easy to lose sight of the fact that heavy and uninterrupted workloads lead to cumulative fatigue and performance decrements. The tendency to "over program" is exacerbated if we fail to understand that activities that seem easy on Earth may be very difficult in space. In his analyses of astronaut journals, Jack Stuster (2010) found that unrealistic work schedules and time related stresses were major concerns for the spacefarer. Tedious work is exacerbated by poor logistics and skimpy or confusing instructions. Furthermore, allowance must be made for the crew to make adjustments in their schedules in response to the real (as compared to the expected) demands of the mission, and to pursue unexpected opportunities for science and discovery. Finally, repetitive and tedious work may increase boredom, already a major concern for a threeyear mission.

Demanding mental tasks require high concentration, accurate perception, memory, problem solving skills, and the ability to juggle two or more tasks simultaneously. Crew members will have devices that will allow them to conduct a confidential self-test of their current mental functioning before undertaking tasks (Dinges, 2010; Kane, Short, Sipes & Flynn, 2005). Rest, sleep, and chronobiological rhythms (including daily or circadian rhythms) affect alertness, vigilance, energy levels, endurance and many performance related variables. This kind of problem is familiar to anyone who has ever experienced "jet lag."

Although in general people require an average of eight hours of sleep per night, spacefarers average about six hours, perhaps less, when they are anticipating critical operations. The internal biological clocks, which affect our biological rhythms are geared or "entrained" to Earth’s 24 hour day. These may be upset during the cruise phase or on Mars where days are slightly longer than on Earth. Insights from humans working on Mars robotic explorations and in lab simulations of Mars time have shown that we can expect work decrements, partly because of the difficulty humans have entraining to a non-24 hour day. Established countermeasures will be needed to help the blue sky based human adjust to conditions on Mars (Whitmore, et. al., 2010, Gronfier, 2007).

4. Teamwork

Each member of the Mars-bound team will have task-relevant knowledge, carefully defined roles and responsibilities, and complementary skills. Tied together by necessity and most likely friendship they will have to achieve high levels of coordination and offer one another support. Still, there have been problems with skilled and talented individuals working together as a team on spaceflights (Kanas & Manzey, 2008; Orasanu, 2005; Shepanek, 2005). These problems need to be avoided by such means as developing shared views of situations and excellent communication skills.

Group dynamics are analyzed in terms of composition, structure, and process. Composition refers to the size of the group and the attributes of its members. Each person must have the technical skills to get the job done and the interpersonal skills to get along with one another. Generally, groups whose members bring many different backgrounds and skills to bear have the highest performance potential, but require the most training to achieve good coordination. We are still in the process of learning how men and women from differing professions and backgrounds can be welded into high performance teams. For example, Gloria Leon (2005) notes that widespread sex-role stereotypes persist, that the first women in new environments may consider themselves under tremendous pressure to succeed, and that some women are burdened by expectations that they serve as "peacemakers" among highly competitive males.

In space, cultural differences including those based on nationality have caused communication difficulties and misunderstanding (Ritsher, 2005). Differences in such areas as food preferences and personal hygiene standards have led to interpersonal frictions, and culturally based interpretations of other astronauts’ behavior have resulted in hurt feelings. Intelligence, professionalism, past cross-cultural experiences, shared training and goals, cultural sensitivity, and mediation help manage cross-cultural differences.

Group structure refers to the relationships among team members. It includes hierarchy and authority (the power vested in a position), the division of labor, rights and obligations, communications channels, and prescribed ways of behaving. Group processes, such as communication and decision making, are channeled by social structure and reflected in the ebb and flow of communication over time. Task and emotion oriented communication will need to be positive and supportive over the duration of the Mars trip to insure better team performance (Fischer, McDonnell, & Orasanu, 2007).

Studies over the years suggest that effective leaders are highly competent and achievement-oriented, self-confident, credible, flexible, and adaptive, as well as concerned about the welfare of their team, and seek opportunities to build morale (Harrison, 2001). Effective leaders subordinate their own needs to those of the crew and the mission. They provide followers with both a sense of direction and emotional support.

They answer questions, solicit opinions, listen to advice, and offer encouragement and criticism. Effective leadership behavior is contingent, or depends upon the demands of the situation and task, and the skill and motivation of the followers (Fiedler, 1967). Although we need more research, considerable progress has been made understanding the intragroup and intergroup relations in space (Kanas &Manzey, 2007). Cockpit resource management (CRM) and naturalistic decision making (NDM) are two potentially useful models. In the CRM model crew members are seen as resources that should be properly managed (Foushee & Helmreich, 1988; Wiener, Kanki & Helmreich, 1993). Leaders understand that individual crew members have useful information that they may need to share in clear and unambiguous ways. CRM includes an authority structure that promotes coordination and communication, consistent high performance standards, and schedules and procedures that help solve rather than exacerbate problems. CRM promotes supportive relationships, and a shared awareness of the situation at hand, and bridges national, organizational, and professional cultures (Merritt & Helmreich, 1996).

As Judith Orasanu (2005) points out, NDM research explores how experts make decisions in complex and demanding real life situations. Space agencies can train astronauts to respond to anticipated problems (such as major system failure) but it cannot prepare them for unexpected problems. In the case of space missions decisions may have to be made rapidly, under conditions of great stress, and with scant information. In the case of a Mars voyage, mission control’s lack of familiarity with on-site conditions coupled with real-time communication delays means that the astronauts cannot rely on direction (or even consultation) with experts on earth. NDM proposes that astronauts should be able to draw on in-depth expertise (as compared to superficial knowledge of procedures) and operate with shared "mental models" of the situation and of themselves as a team. Decisions will meet all minimal requirements (satisfice or "make due") rather than constitute the best possible decision (optimize). Different team members will have to monitor and check each others’ work and take responsibility for decisions that "fall outside of their job description" or "exceed their pay grade."

Early American space missions were micro-managed by NASA but over the years the locus of decision making shifted towards the astronauts in flight. A Mars mission will require yet another shift in this direction of crew autonomy. In a sense, a crew setting forth for Mars will be comparable to a Roman Legion marching off on a long trek to a distant land. Self-sufficiency is the only viable option.

6. Conclusion

In this review we presented an introductory overview of human factors and behavioral health as they relate to a Mars mission. We favored breadth over depth. Each reference that we cited resembles the tip of an iceberg; in that dozens if not hundreds of other references remained invisible below the surface.

Many of the basic human factors issues associated with a voyage to Mars have received attention since Project Mercury. Others have become salient during Skylab, shuttle flights, and aboard modern space stations including Mir and the ISS. We now know that a classical human factors program, based on disciplines rooted in biology and engineering, must be expanded to include specialties rooted in the behavioral and social sciences.

Over the years many prestigious commissions and panels have offered strident calls for increased research on psychological factors contributing to performance and what we now call behavioral health. Limited funds are only one of the factors that have delayed behavioral research (Harrison, 2005; Palinkas, Allred &Landsverk, 2005). By some accounts NASA culture was protective of the "right stuff" image and was not favorably disposed to research or news reports that might draw attention to psychological issues that create unfavorable publicity (Harrison, 2005; Santy, 1994; McCurdy, 1997).

Astronaut culture is another factor. Self-sufficient, hard working and success-driven people do not want to somehow appear less than optimal or needy and for this reason tend to be private and protective of one another. After all, who would want to be disqualified from a flight on the basis of an observation taken in the course of an experiment or a decision rule based on psychological research? Voluntary participation – and it must be voluntary – rests on astronaut perceptions that the benefits of participating in research outweigh the risks, and that their involvement will not somehow be used against them (Shepanek, 2005). Engineers may be impatient to "get on with the metal bending," even before behavioral requirements are fully understood. Then, too, behavioral issues can be complex, demanding, and have no simple answers. Over the years many research projects have contributed more to theory than to practice which may be great for academia but not particularly helpful when it comes to space flight operations. Behavioral researchers who want to be taken more seriously should seek principles that are quantifiable and directly applicable to specific space missions. In the area of human behavior, thorough preparation for a Mars mission will require an overall integrated research program, consistent funding, developing understanding and synergy among many subcultures, and behavioral research with straightforward implications for the mission (Palinkas et. al., 2005).

In the United States one recent step to the future is NASA’s (2007, 2010) Human Research Program, whose many goals include ensuring that the crew can perform the physical, mental and team tasks required for a return to the Moon and a voyage to Mars. We will become prepared, also, by results from long term simulations and other research conducted by the Canadian Space Agency, the European Space Agency, the Russian Space Agency, Japan Aerospace Space Agency and other space agencies (Harris, 2003, Mohanty, et. al., 2006).

Already today, experience gained in space, coupled with that gained in space-flight analogous environments such as undersea habitats, polar outposts, and caves help us to glimpse the behavioral requirements for a Mars crew. We expect strong behavioral health of the individual and the crew as a group to encourage high performance and the satisfactions of mastery and achievement to bolster behavioral health. On the other hand poor behavioral health or dwindling performance could initiate a vicious downward spiral, and that should not be an option.