Operational and Human Factors Implications of Physiological Deconditioning in Long Duration Spaceflight

A major factor in determining the success of any manned long duration space mission will be how well the human body can endure the microgravity environment. Data collected from long duration space missions conducted by both the United States and the former Soviet Union have shown that almost every system in the human body is adversely affected by microgravity. These adverse affects, taken individually or in concert, can have operational implications for a long duration space mission. Data collected to date indicate that significant human factors complications could arise due to the deconditioning of the musculoskeletal, cardiovascular and hematological systems that occur in a microgravity environment, resulting in decrements in overall astronaut performance. This paper examines some of these deconditioning effects, their immediate operational implications and possible countermeasures.