Discussed is the problem of professional reliability of cosmonauts simulating manual docking of transport vehicle SOYUZ-TM to space station MIR during acute adaptation to microgravity. A new concept of cosmonaut's reliability qualification is based on the parameters that characterize the systemic body response to job-related factors: integral efficiency and psychophysiological "cost". Justification is given to the statistic methodology of the change-over from prime job quality indices and the functional state of human to integral. Underlined is the possibility to apply this methodical approach to enhancement of the program of assessment and recovery of the professional reliability of cosmonauts in flight.