Some problems of group interaction in prolonged space flights.

The objective of this paper is to describe psychological phenomena which has developed in the course of inter- and intragroup interaction in space. Several objective reasons are stressed which comprise the basis of the formation of the majority of the psychological phenomena. The authors also discuss prediction of these phenomena, namely, can they occur on the International Space Station (ISS) and what countermeasures will prevent them. In the analysis, the authors rely on the practice of prolonged spaceflight (PSF) psychological support in Russia; preliminary results of several flights within the Mir/NASA project; the personal experience of cosmonaut Valery V. Polyakov; and data gained during prolonged studies simulating PSF conditions (isolation, microgravity, etc.).