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Details

Chronic Exposure to Moderately Elevated CO2 During Long-Duration Space Flight.

N20120006045

Publication Date	2012
Personal Author	Cronyn, P. D.; Watkins, S.; Alexander, D. J.
Page Count	28
Abstract	Out of operational necessity, space platforms function with ambient carbon dioxide (CO2) concentrations in excess of normal atmospheric conditions (0.03% or partial pressure of 0.23 mmHg). NASA's long-duration Spacecraft Maximum Allowable Concentration for CO2 is 0.7% (pp CO2 of 5.3mmHg). Extensive terrestrial studies support this level as safe and unlikely to cause adverse effects; however, International Space Station crews routinely report symptoms of acute CO2 toxicity (e.g., headaches, lethargy) that correlate with relative elevations of cabin CO2 below the permissible level. It is unclear if the unique environment of space results in increased sensitivity to CO2 or if other confounding factors are present. Regardless, acute symptom presentation at levels significantly lower than expected prompts the need to reevaluate the potential for adverse effects from long-term exposure. NASA's continued commitment to long-duration space flight makes it imperative to evaluate the impact of chronic exposure on the mission and astronaut health. With no definitive research to provide insight into current symptoms, potential avenues of action include incorporating quantifiable methods of measuring crew CO2 burden, developing a robust study to examine various low-to-moderate CO2 concentrations on human subjects in microgravity and/or implementing design requirements for reduced CO2 levels on future space platforms.
Keywords	Astronauts Carbon dioxide concentration Health Manned space flight Spacecraft atmospheres Astronaut performance International space station Aerospace medicine
Source Agency	National Aeronautics and Space Administration
Corporate Authors	National Aeronautics and Space Administration, Houston, TX. Lyndon B. Johnson Space Center.
Supplemental Notes	Text in English. Publicly available Unlimited Distribution as joint owner in the copyright. CASI.
Document Type	Technical Report
NTIS Issue Number	201222

Chronic Exposure to Moderately Elevated CO2 During Long-Duration Space Flight.

Chronic Exposure to Moderately Elevated CO2 During Long-Duration Space Flight.
N20120006045

Publication Date	2012
Personal Author	Cronyn, P. D.; Watkins, S.; Alexander, D. J.
Page Count	28
Abstract	Out of operational necessity, space platforms function with ambient carbon dioxide (CO2) concentrations in excess of normal atmospheric conditions (0.03% or partial pressure of 0.23 mmHg). NASA's long-duration Spacecraft Maximum Allowable Concentration for CO2 is 0.7% (pp CO2 of 5.3mmHg). Extensive terrestrial studies support this level as safe and unlikely to cause adverse effects; however, International Space Station crews routinely report symptoms of acute CO2 toxicity (e.g., headaches, lethargy) that correlate with relative elevations of cabin CO2 below the permissible level. It is unclear if the unique environment of space results in increased sensitivity to CO2 or if other confounding factors are present. Regardless, acute symptom presentation at levels significantly lower than expected prompts the need to reevaluate the potential for adverse effects from long-term exposure. NASA's continued commitment to long-duration space flight makes it imperative to evaluate the impact of chronic exposure on the mission and astronaut health. With no definitive research to provide insight into current symptoms, potential avenues of action include incorporating quantifiable methods of measuring crew CO2 burden, developing a robust study to examine various low-to-moderate CO2 concentrations on human subjects in microgravity and/or implementing design requirements for reduced CO2 levels on future space platforms.
Keywords	Astronauts Carbon dioxide concentration Health Manned space flight Spacecraft atmospheres Astronaut performance International space station Aerospace medicine
Source Agency	National Aeronautics and Space Administration
Corporate Authors	National Aeronautics and Space Administration, Houston, TX. Lyndon B. Johnson Space Center.
Supplemental Notes	Text in English. Publicly available Unlimited Distribution as joint owner in the copyright. CASI.
Document Type	Technical Report
NTIS Issue Number	201222