Compatible atmospheres for a space suit, space station, and shuttle based on physiological principles

Area of Science:

• Physiology
• Aerospace Medicine
• Biotechnology

Background:

• Designing compatible environments for space exploration requires understanding physiological responses to pressure changes.
• Decompression sickness, or 'the bends,' is a known risk for astronauts and aviators, influenced by bubble formation and blood flow dynamics.

Purpose of the Study:

• To outline the physiological principles for designing integrated space environments (spacecraft, space station, space suit).
• To establish protocols enabling astronauts to transition between different pressure environments without prebreathing oxygen.
• To assess and minimize the risk of decompression sickness during extravehicular activities (EVA).

Main Methods:

• Application of fundamental physiological principles, including tissue memory of decompression and blood flow characteristics in connective tissues.
• Modeling decompression sickness incidence using the Weibull distribution based on bubble volume.
• Simulating astronaut transitions between spacecraft (11.9 psia) and space station (8.7 psia) environments using a 30% O2/N2 mix.

Main Results:

• A protocol allowing astronauts to move from a spacecraft to a space station and then perform EVA without oxygen prebreathing was designed.
• The current space suit operating at 4.3 psia has an estimated decompression sickness incidence of less than 0.5%.
• Increasing space suit pressure to 6.5 psia is predicted to reduce the incidence of decompression sickness to zero.

Conclusions:

• Fundamental physiological principles can be successfully applied to design safe and efficient space environments.
• The developed protocol significantly enhances astronaut flexibility and safety during space missions.
• Optimizing space suit pressure is a critical factor in completely mitigating decompression sickness risks.