Carbon Dioxide as a Multisystem Threat in Long Duration Spaceflight

Area of Science:

• Space medicine
• Environmental physiology

Background:

• International Space Station (ISS) environments often exceed safe carbon dioxide (CO2) partial pressure (Pco2) thresholds.
• Microgravity exacerbates CO2 risks through localized "pockets" and amplified fluid shifts, impacting astronaut health.
• Chronic hypercapnia poses risks including neuro-ocular syndrome, bone demineralization, and kidney stones.

Purpose of the Study:

• To discuss the multisystem health threats posed by elevated CO2 during long-duration spaceflight.
• To highlight the compounded risks of CO2 exposure and microgravity on astronaut physiology.
• To advocate for integrated strategies to mitigate CO2-related health effects for future space exploration.

Main Methods:

• Review of current evidence on CO2 toxicity in spaceflight.
• Analysis of physiological impacts of hypercapnia in microgravity.
• Discussion of engineering controls, countermeasures, and monitoring strategies.

Main Results:

• Elevated Pco2 in spaceflight leads to hypercapnic symptoms like headaches and cognitive impairment.
• Microgravity amplifies CO2 effects on cerebral circulation and intracranial pressure.
• Long-term CO2 exposure raises concerns for bone and kidney health.

Conclusions:

• Carbon dioxide represents a significant multisystem threat to astronaut health during long missions.
• Integrated strategies involving engineering, countermeasures, and monitoring are essential for mitigating CO2 risks.
• Addressing CO2 challenges is vital for ensuring astronaut well-being and mission success on lunar and Martian expeditions.