Written by Michael Wilkinson, New York.
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If you’ve been tracking the data from the ExoLab on orbit, you may have noticed something very interesting in the carbon dioxide levels. All winter they have been running extremely high, which is creating an unhealthy atmosphere on the station. You may have heard Scott Kelley comment on how his partner Amiko could tell when CO2 levels were up by his mood when she was talking to him. But I digress.
My 4th graders noticed an extreme drop in CO2 on the 13th of April, so we messaged a friend of mine who is an ISS flight controller. He looked into it and found that the logs show that ETHOS was working with the carbon dioxide scrubbers in April. He’s not sure exactly what they did, but it is clearly working better than it has been. The real name is “Carbon Dioxide Removal Assembly” (CDRA) or /see-druh/.
From my friend…
“There are three active carbon dioxide removal systems in ISS. two owned by NASA called CDRA, one owned by Roscosmos called Vozdukh. One CDRA is in the LAB, one CDRA is in Node 3. Generally, we try to run only one CDRA at a time to keep the other one in reserve. They are finicky devices because they have so many complex parts both moving and chemical reaction. so they fault out relatively frequently. This leads to frequent and unexpected reconfiguration. I don’t know what exactly went on in April but I see at least one each of LAB and Node 3 CDRA activation on the plan. so it could be they turned both on when previously only one was on and now levels are lower.”
Here are some white papers on the CDRA: