[Results of hematological examinations of crew members of the space vehicles EO-2, EO-3 and EO-4].

The authors' opinion that adaptation inhibition of erythron functioning under weightlessness produces an unfavourable effect on the optimal physical state of a cosmonaut and his working capacity in the post-flight period has been confirmed by the analysis of certain hematological parameters studied in cosmonauts. The data obtained have necessitated investigation of threshold values of erythron functioning under weightlessness, and creation of artificial gravitation on board the piloted space ship to normalize erythropoiesis. Investigation of these problems of space hematology would be helpful in validation of the limits of human's long-term stay under weightlessness, and in the pre- and post-flight period management.