LOG ENTRY: SOL 199 (May 28, 2036)
I’ve got it. I know how to power the Oxygenator and Atmospheric Regulator.
The problem with small pressure vessels is CO2 toxicity. You can have all the oxygen in the world, but once the CO2 gets above 1% you’ll start to get drowsy. At 2% it’s like being drunk. At 5%, it’s hard to stay conscious. 8% will eventually kill you. Keeping alive isn’t about oxygen, it’s about getting rid of CO2.
I need the regulator. But I don’t need the Oxygenator all the time. I just need to get CO2 out of the air, and back-fill with oxygen. I have 50 liters of liquid oxygen in two 25L tanks here in the Hab. That’s 50,000L in gaseous form, enough to last 85 days. Not enough to see me through to rescue, but a hell of a lot.
The regulator can separate the CO2 and store it in a tank, adding oxygen to my air as needed. When I run low on oxygen, I can camp out for a day and use all my power to run the Oxygenator. That way, the Oxygenator’s power consumption doesn’t eat up my driving juice.
So I’ll run the regulator all the time, but only run the Oxygenator on days I dedicate to using it.
After the regulator freezes the CO2 out, the oxygen and nitrogen are still gasses, but they’re -75C. If the regulator fed that back to my air without reheating it, I’d be a Popsicle within hours. Most of the regulator’s power goes to heating the return air so that doesn’t happen.
But I have a better way to heat it up. Something NASA wouldn’t consider on their most homicidal day.
The RTG!
Yes, the RTG. You may remember it from my exciting trip to Pathfinder. A lovely lump of Plutonium so radioactive it gives off 1500 watts of heat which it uses to harvest 100W of electricity. So what happens to the other 1400W? It gets radiated out as heat.
On the trip to Pathfinder, I had to actually remove insulation from the rover to vent excess heat from the damn thing.
I ran the numbers. The regulator uses 790W to constantly reheat air. The RTG’s 1400W is more than equal to the task, as well as keeping the rover a reasonable temperature.
To test, I shut down the heaters in the regulator and noted its power consumption. After a few minutes I turned them right back on again. Jesus Christ that return air was cold. But I got the data I wanted.
With heating, the regulator needs 21.5pn. Without it… (drum roll) 1pn. That’s right, almost all of the power was going to heat.
As with most of life’s problems, this one can be solved by a box of pure radiation.
I spent the rest of the day double-checking my numbers and running more tests. It all checks out. I can do this.
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