I think it downplayed the importance of CO2 scrubbing, because we can tolerate low O2 a lot easier than high CO2. High CO2 is also what gives us that suffocating feeling.
It briefly touches on rebreathers near the end. The theory behind them is that the difference between the %O2 on the inhale and exhale of our breathing cycle is very little. So if you can get rid of the CO2, you can re-breathe that same air for a “long” time before it starts to get too low in O2 content and it starts to impact your survivability.
There are ways of creating oxygen onboard submarines. The only real limits to time submerged is the amount of food the boat can carry.
Here is a video by Destin from the Smarter Every Day youtube channel explaining oxygen generation onboard submarines. https://youtu.be/g3Ud6mHdhlQ
I think it downplayed the importance of CO2 scrubbing, because we can tolerate low O2 a lot easier than high CO2. High CO2 is also what gives us that suffocating feeling.
It briefly touches on rebreathers near the end. The theory behind them is that the difference between the %O2 on the inhale and exhale of our breathing cycle is very little. So if you can get rid of the CO2, you can re-breathe that same air for a “long” time before it starts to get too low in O2 content and it starts to impact your survivability.