This study investigated the time-courses and the relationships between coping, defense mechanisms, emotions and depression considered as key factors in adaptation to ICE (Isolated and Confined Extreme) environments. During the space simulation, the Mars-105 experiment, positive emotion decreased significantly and significant positive correlations were found between mature defenses and both positive emotions and Task-Oriented Coping (TOC), as well as between Disengagement-Oriented Coping (DOC) and symptoms of depression. These findings show the impact of space simulation on affective states and the relations of defense to both coping and emotion, which underline the role of these psychological constructs involved in psychological adaptation processes. The results of the present study add insights into the effects of space simulation in order to offer the participants a better selection, preparation and follow-up of these psychological components recognized as essential for adaptation to extreme environments.