Nick Kanas, a professor of psychiatry at the University of California, San Francisco, replies:

"You raise a very interesting question. I have reviewed more than 60 reports from studies conducted in space-analogue environments, such as in Antarctica, submarines, land-based and submersible simulators, and from studies of hypodynamia, or confined bed-rest. Many of these have lasted months to a year or more (Antarctic missions and Biosphere 2, for example). My colleagues and I have called into question the salience of such analogue studies for manned space missions, however, especially for issues involving the psychosocial functioning of crew members. For instance, there is some evidence that crew anxiety is expressed differently during Antarctic missions than during hyperbaric (high-pressure) chamber studies because of the differing psychological meanings and degree of danger in these two isolated environments.

"The anecdotal literature (drawn from briefings and reports, for instance) suggests that groups of people working under long-term isolated conditions go through phases of tension and cohesion. For example, the Russians have found that depression-like 'asthenic reactions' are most likely to occur during the long, monotonous middle part of their space missions. Crew tension also seems to be related to crew heterogeneity, as reflected by such factors as gender, cultural background, native language and level of career motivation. People in isolated groups sometimes displace their intra-group tension and anger to the monitoring people on the outside. Finally, in terms of leadership, both task and supportive leadership roles are important for mission success, depending upon the work demands and the degree of monotony experienced by the crew members.

"Despite the presence of such anecdotal reports, I am not aware of any reports involving scientific studies of psychosocial issues during long-duration manned U.S. and Russian space missions. In a new study funded by NASA, my colleagues and I are studying crew-member and mission-control tension, cohesion and leadership issues that arise during five NASA/Mir space missions, each lasting four to six months. We hope to gather data that will be of use in training and supporting future crews involved with the international space station and perhaps with a future mission to Mars."

JoAnna Wood of the Psychology and Behavior Laboratory at the National Aeronautics and Space Administration's Johnson Space Center offers the following information:

"There has been a fair amount of research on this topic conducted in the Arctic and Antarctic, two areas where isolation is a common occurrence, as well as other extreme environments, such as naval submarines. These studies tend to suffer from the same methodological limitations, however. They may show the gross psychological changes that took place between the time when people entered an isolated environment and when they returned (subclinical depression being the most common symptom), but they do not generally document the detailed fluctuations of mental state that occur during isolation.

"Now, with the advent of notebook computers and refined statistical analysis techniques, we are getting a much clearer picture of what happens to people in long-duration isolation. These data come from various sources. For a little over three years, we have been involved in a collaborative project between the Johnson Space Center and the Australian government's Antarctic Division, in which we study Australian expeditioners while they are stationed in small groups at Antarctic research bases for periods up to 15 months, as well as two 100-day, six-person Antarctic traverses. We share advice and recommendations. My group has also collected information from an Antarctic traverse conducted by a French and Italian group.

"Here at the Johnson Space Center, we have just started collecting data from small crews that spend time in the Life Support Integration Facility. This facility is used for engineering and testing the kinds of life-support systems that would be used on long-duration space missions, such as a manned mission to Mars (including closed-loop systems that recycle water and air). We are studying the people who work on this project while they live with their equipment inside the facility for 30 to 60 days at a time. This sort of study is very important because it allows a comparison with the Antarctic crews. We can begin to explore variations in the motivations of the people in isolated environments and of the stresses they encounter in the different environments.

"From all these studies, we are finding that there is not just a simple decline in psychological well-being over time; many of the changes in mental state occur in response to specific events. It is not just the isolation that does people in--the psychological changes they experience also depend on the emotional baggage that people bring with them, how they interact with the other people with whom they are isolated, what kind of events they experience while isolated, and so on There are tremendous variations among people; two individuals in an Antarctic station at the same time may have extremely different experiences. In fact, the same individual may have vastly different experiences on different expeditions, depending on the events and persons they encounter.

"Ours is operational, rather than basic, research. We will not arrive at universal truths about human nature from these studies. What we will do is come up with some generalizable themes: the kinds of personalities that make up a good crew, the kinds of problems (such as stress) that can be prevented, the kinds of countermeasures that would make life easier for people in isolated settings. It may prove helpful to train people in conflict resolution and in stress reduction and stress management techniques. We want to learn more about how to select for good interpersonal skills. We are studying the benefits of crew autonomy (allowing crews to set their own schedules and activities) and how much support and contact with family and friends people need. We are trying to understand more about leadership abilities. Finally, we are trying to understand more about the complex interactions between remote crews and their at-home management and support personnel.

"The Johnson Space Center is the lead NASA center for isolation studies. It is not a big project and does not involve a lot of money, but the results may be useful in a number of isolated settings: Antarctic bases, lengthy space missions, military outposts and remote oil rigs, for example. Whatever the environment, we are trying to find out how to optimize the comfort and compatibility in a group and to reduce the interpersonal tensions and psychological discomfort that can reduce productivity.