The Influence Of The Dynamic Environment On Man In Space Flight

  • Edwin P. Hiatt


Possible stresses in space flight include a broad mechanical spectrum. In this paper most of the emphasis will be placed on transient and prolonged linear accelerations though it is recognized that vibrations and rotations could become important.

In preparing manto be exposed to the prolonged accelerations of space flight it was realized that his body orientation in the force field was of great importance if he was to maintain his capacity for observing and ability to perform tasks. By arranging for these forces to be applied across his body (transversely), instead of along the length of his body, circulatory difficulties can be reduced and his tolerance increased. However, at the higher accelerations tolerable in the transverse position other difficulties appear most by involving respiration. Not only is it more difficult to inspire air, but, because of a displacement of the blood perfusing the lungs, there is imperfect exchange between pulmonary air and blood. This physiological pulmonary shunt results in a reduction in the oxygen content of arterial blood. Furthermore, the inertial forces due to acceleration may cause congestion of some portions of the lungs with overdilation of other portions with danger of atelectasis and mediastinal emphysema.

It is pointed out that neither positive pressure respiration, the breathing of high oxygen pressures nor immersion in water can completely protect against these changes.

The status of our knowledge of the tolerance of man to abrupt transient accelerations is reviewed with some discussion of the difficulties of investigation in this field.

Though the orbital flights made to date have tended to reassure us that man can tolerate the dynamic environment of space flight, there are possible deviations from normal flight plans which could involve dangerous forces. Some of these are described.


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Copyright information

© Springer-Verlag Wien 1965

Authors and Affiliations

  • Edwin P. Hiatt
    • 1
  1. 1.Department of PhysiologyOhio State UniversityColumbusUSA

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