[Factor analysis of reactions to lower body negative pressure on the earth and during space flight]

The method of main components was used to examine separately the cosmonauts' responses to LBNP tests on the ground and in space flight. The factor structures of the ground- and flight data did not show significant differences. In both cases the first factor can be termed the factor of venous return and the second, the factor of the cardiac state. The first two factors were responsible for about 60%, and the first three factors for 76-78% of data scatter. The observation that the factor structure remains unchanged indicates that LBNP reactions in space flight can be evaluated using the criteria applied on the Earth.