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Let's say that I want to colonize a planet which is basically like mars but has got an atmosphere which still has extremely low pressure but consists mainly of oxygen. The temperatures are more or less comfortable, ranging from -10*C to +20*C. The surface pressure is 6-7% of that on earth, with water boiling at 25-30*C.

No need to worry about radiation - either the star is a red dwarf or the planet has a strong magnetic field. Radiation is no more than 10 times bigger than on earth.

Now...I am actually Scrooge McDuck and I want to mine gold on the planet, but shipping air or compressing the air that is already there is too expensive.

Can I do the following?:

  • Put the settlers in colony domes first. Let's say we start at 50% of sea level pressure, more or less comfortable.
  • Start decreasing the air pressure slowly. Let's say the pressure decreases by 10% every month to allow adaptation.
  • I will remove the Nitrogen from the air gradually
    • Because the atmosphere of the planet consists mainly of oxygen
    • To make the atmosphere more breathable, removing excess gases and replacing them with oxygen is a good idea, isn't it?
  • I will continue doing this until I can effectively remove the dome.
  • If required, the "weaning off" process can continue for several generations.
  • Let's say I have chosen mainly people from the Andes and from the Himalayas for my project, so they are adapted to high altitude environments.

Is my idea good? If not very good, what should I consider changing? How quick should the decompression processes be? Can I grow plants and have livestock (himalayan sheep?) in such an environment? Can humans actually survive in that environment?

I assume that cooking by boiling, medical procedures, etc... will happen in pressurised chambers.

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  • $\begingroup$ Wouldn't the water in a 37 C human body boil away in this environment? $\endgroup$ – Frostfyre Aug 31 '15 at 16:32
  • $\begingroup$ They would need to be trained to breathe that much oxygen as well!! $\endgroup$ – Mikey Aug 31 '15 at 16:33
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At these low pressures, adaptation is not possible. The key is your observation that "with water boiling at 25-30*C". Since normal body temperature is 37 C, while blood does not boil, saliva and all the fluid in the lungs which lubricate the alveoli will instantly boil off. Not to mention your eyes losing all lubrication from tears, which will shortly produce blindness due to friction with the eyelids.

This is an example of the Armstrong Limit, and this limits minimum pressure to just about 10% of sea level, even with pure oxygen.

Of course, I'm sure that you recognize that plants do just fine on this world, since a high oxygen level cannot exist without some sort of biological process in place, although the existence of a robust oxygen-producing ecology operating at these low temperatures will take a certain amount of explanation/handwaving.

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