Crewmember and ground personnel interactions over time during Shuttle/Mir space missions

Background: Anecdotal reports from space and results from simulation studie s on Earth have suggested that space crewmembers may experience decrements in their mood and interpersonal environment during the 2(nd) half of the mi ssion and that negative emotions may be displaced to outside monitoring per sonnel. Methods: To evaluate these issues, we studied 5 American astronauts , 8 Russian cosmonauts, and 42 American and 16 Russian mission control pers onnel who participated in the Shuttie/Mir space program. Subjects completed questions from the Profile of Mood States, the Group Environment Scale (GE S), and the Work Environment Scale (WES) on a weekly basis during the missi ons. Subscale scores from these measures were analyzed using a piecewise li near regression approach that analyzed normally distributed subscales using a mixed model and non-normally distributed subscales by dichotomizing the variables and using a generalized estimating equation. Results: After prote cting against possible Type I errors due to multiple significance tests, on ly weak support was found for the biphasic model: the only significant find ings in favor of the hypothesized 2(nd) half decrements in the interpersona l environment were in crewmember GES Leader Support and astronaut WES Work Pressure. Strongly consistent confirmation was found on all six tested meas ures for the hypothesized displacement of tension and dysphoria from crewme mbers to mission control personnel. The hypothesized displacement of tensio n and dysphoria from mission control personnel to management was found on f ive of the six tested measures. Conclusions: The absence of moderate to str ong support for the biphasic model suggests that crewmember interpersonal f unctioning does not depend appreciably on 1(st) half/2(nd) half time effect s. The consistent support found for the displacement of tension and dysphor ia suggests that countermeasures need to be developed to deal with this phe nomenon in both crewmembers and mission control personnel.