Difference between revisions of "Carbon Dioxide Scrubbers"
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A steady supply of oxygen alone is insufficient to keep astronauts breathing. While the intake of oxygen is essential for respiration, the by-product of this respiration is the exhalation of approximately one kilogram of carbon-dioxide per day.<ref name=":1">James, J. T., & Macatangay, A. (2009). ''Carbon Dioxide – Our Common “Enemy.”'' 8.</ref> The concentration of this gas in Earth's atmosphere is roughly 0.04%, but in the close confines endured by astronauts, accumulations of CO<sub>2</sub> can quickly reach toxic levels.<ref name=":0">Freudenrich, C. (2011). How is carbon dioxide eliminated aboard a spacecraft? | HowStuffWorks. Retrieved August 15, 2019, from HowStuffWorks website: <nowiki>https://science.howstuffworks.com/carbon-dioxide-eliminated-aboard-spacecraft.htm</nowiki></ref> | A steady supply of oxygen alone is insufficient to keep astronauts breathing. While the intake of oxygen is essential for respiration, the by-product of this respiration is the exhalation of approximately one kilogram of carbon-dioxide per day.<ref name=":1">James, J. T., & Macatangay, A. (2009). ''Carbon Dioxide – Our Common “Enemy.”'' 8.</ref> The concentration of this gas in Earth's atmosphere is roughly 0.04%, but in the close confines endured by astronauts, accumulations of CO<sub>2</sub> can quickly reach toxic levels.<ref name=":0">Freudenrich, C. (2011). How is carbon dioxide eliminated aboard a spacecraft? | HowStuffWorks. Retrieved August 15, 2019, from HowStuffWorks website: <nowiki>https://science.howstuffworks.com/carbon-dioxide-eliminated-aboard-spacecraft.htm</nowiki></ref> | ||
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Revision as of 19:35, 15 August 2019
[This is an article in progress, and is currently being written]
Why Must C02 Be Removed?
A steady supply of oxygen alone is insufficient to keep astronauts breathing. While the intake of oxygen is essential for respiration, the by-product of this respiration is the exhalation of approximately one kilogram of carbon-dioxide per day.[1] The concentration of this gas in Earth's atmosphere is roughly 0.04%, but in the close confines endured by astronauts, accumulations of CO2 can quickly reach toxic levels.[2]
| CO2 Concentration | Symptoms |
|---|---|
| 1% | Drowsiness |
| 3% | Impaired hearing, increased heart rate and blood pressure, stupor |
| 5% | Shortness of breath, headache, dizziness, confusion |
| 8% | Unconsciousness, muscle tremors, sweating |
| >8% | Death |
NASA has set strict limits of acceptable CO2 concentration on spacecraft. The longer the duration of the flight, the lower the permissible maximum: for example, while allowing a maximum of 2% for a one-hour period, NASA recommends that the concentration not exceed 0.5% over a 1000-day stay[1] (an as-yet hypothetical duration, as the record for longest consecutive stay in space at the time of writing is held by Russian cosmonaut Valery Polyakov at 438 days[3]). The proportionate decrease in concentration acceptability in accordance with duration accounts for the fact that the longer the period of time, the higher the likelihood of CO2-induced behavioral changes negatively affecting missions requiring close personal contact in confined spaces.
Moderating CO2 levels over such a long period of time naturally implies weight and power demands, yet NASA has adopted more stringent regulations than the Navy, which allows up to 2.5% concentrations for submarine personnel over a 24-hour period.[1] While both types of crews operate in a confined area with an artificially-regulated atmosphere, repairing a CO2 removal system in space constitutes a potentially more complex task where one cannot simply surface in the event of an unsuccessful attempt brought on by concentration difficulties. Hypothetically, a well-developed Mars colony could relax such limitations slightly once it is large enough to contain multiple fail-safes and back-ups, thereby reducing the energy demands on the colony as a whole.
- ↑ 1.0 1.1 1.2 James, J. T., & Macatangay, A. (2009). Carbon Dioxide – Our Common “Enemy.” 8.
- ↑ 2.0 2.1 Freudenrich, C. (2011). How is carbon dioxide eliminated aboard a spacecraft? | HowStuffWorks. Retrieved August 15, 2019, from HowStuffWorks website: https://science.howstuffworks.com/carbon-dioxide-eliminated-aboard-spacecraft.htm
- ↑ Wall, M. (2019). Most Extreme Human Spaceflight Records of All Time | Space. Retrieved August 15, 2019, from Soace.com website: https://www.space.com/11337-human-spaceflight-records-50th-anniversary.html
