How isolated and confined-environment missions shape human interactions: SIRIUS-21

In recent years, manned space missions have advanced towards aiming for the Moon and Mars, underscoring the critical importance of accumulating knowledge on the long-term changes in human interactions within isolated and confined environments (ICE). This study investigated the dynamics of human interactions among the crew participating in the 240-day closed experiment named SIRIUS-21 (Scientific International Research in Unique Terrestrial Station) in Moscow, Russia. Using sociometric tests, data on human interactions during task-related and private times were collected separately. The results indicated dynamic changes in human interactions during the initial stages of the mission, followed by stabilization in the later stages. Interpersonal conflicts emerged among the crew during the initial phase of the mission, prompting intervention by psychological specialists. Furthermore, evaluation of human interactions during task-related and private times revealed a trend towards the blurring of boundaries between task-related and private interactions as the mission progressed. Additionally, while a persistent tendency of mutual exclusion was observed between certain individuals within the crew, the Cohesion scores remained approximately 1.0 in both task-related time and private time, and performance levels were consistently high. These findings suggest that timely intervention by external specialists may be effective in stabilizing team dynamics and that interpersonal conflict or the unification of task-related and private relationships does not necessarily have a negative impact on team functioning. In future manned space missions aimed at the Moon or Mars, awareness of the potential risks associated with the blurring of boundaries between task-related time and private time will be essential. By utilizing tools such as sociograms to visualize and monitor interpersonal relationships and psychological safety, early detection of issues and timely interventions may become possible. • The purpose of this study was to quantify human interactions. • Results show dynamic changes in interactions early on, stabilizing later. • Individual interactions worsened, but group cohesion remained. • Interactions between task-related and private times blurred as time progressed.