Prevention of decompression sickness during a simulated space docking mission

Area of Science:

• Space Medicine
• Aerospace Physiology
• Human Factors in Spaceflight

Background:

• Spacecraft atmosphere compatibility is crucial for crewed missions.
• Previous concerns existed regarding decompression sickness during inter-spacecraft transfers.

Purpose of the Study:

• To assess the risk of decompression sickness during simulated transfers between Apollo and Soyuz spacecraft atmospheres.
• To evaluate the safety of specific pressure and gas composition exchanges.

Main Methods:

• Simulated repetitive exchanges between 100% oxygen at 5 psia (Apollo) and 30% oxygen-70% nitrogen at 10 psia (Soyuz) in altitude chambers.
• Seven crewmen participated in 11 tests over three 24-hour periods, with three transfers per period.
• Monitoring for symptoms of decompression sickness, including the bends, and conducting biochemical tests and fatigue assessments.

Main Results:

• Absence of any form of decompression sickness, specifically the bends, in all seven crewmen across 11 tests.
• No subjective pain or significant fatigue reported by participants.
• Biochemical tests did not indicate adverse physiological responses.

Conclusions:

• Repetitive transfers between Apollo and Soyuz simulated atmospheres are unlikely to cause decompression sickness.
• The tested transfer protocol, including adaptation in a docking module airlock, appears safe for crew health.
• Findings support the feasibility of joint crewed missions involving different spacecraft environments.