Six participants of Mars-500 were examined to obtain information about intrapersonal conflicts and life spheres with high emotional tension associated with them by participation in an experiment with prolonged group isolation. The investigation was performed using operational analogy-based neurosemantic psychodiagnostics, with the subconscious regarded as a semantic filter with unstructured semantic information at the input and information structured by the inner world content at the output. The results shed light on the semantic structure of the subjective experience and functioning of protective mechanisms, as well as organizational levels and modality of emotional experience. Before and after a 520-day isolation, all the participants were shown to have intrapersonal conflicts and high emotional tension in the socio-professional sphere, caused by the family/sexual and interpersonal relations and self-assessment, and concerns about life and health. On completion of the isolation, the psychoemotional tension was reduced in interpersonal relations and increased in family/sexual ones.