Luna and Mercury terraforming

[Kaiser (OP)]

Hi guys, I'm new on forum but I'm quite confident with aurora ))

After a long research, I have not find any topic related to this, so I opened a new 3D. . .

I delivered 4 terraformes on Luna.  Before I begin to add any gas, could you suggest me a good way to create an atmosphere there for humans (with percentages and atm), since there's no atmosphere at all?
Could you explain me the same for Mercury?

Thanks

[TheDeadlyShoe]

there's 3 factors that lead to a breathable atmosphere

-Breathable gas (oxygen for the most part) must be within a certain range, determined by race
-Pressure must be within a certain range, determined by race
-There cannot be ANY dangerous gases

The easiest way to create a breathable atmosphere on a body with no atmosphere is to manufacture Oxygen until you reach the minimum requirement. For Humans, in version 6 and above, it's 0.1 atmosphere.  Then switch to creating Nitrogen (say 0.3atm) Eventually you will be alerted that a breathable atmosphere has been created.

The fly in this ointment is temperature.  Even with a breathable atmosphere, many worlds will be too warm or too cold to be fully habitable.  Humans in version 6 have an ideal temperature of 14C with a deviation of 24C, meaning they can comfortably inhabit worlds with 'surface temperatures' ranging from -10C to 48C.   The thickness of atmosphere and the presence of greenhouse gases can raise the temperature of a planet.  Anti greenhouse gases can lower it.  The Moon has a base surface temperature of -53C, which is fairly easy to deal with.  After you have a breathable atmosphere you can simply add a greenhouse gas until the temperature reaches a comfortable range.

Mercury is only slightly more difficult. Mercury has a base temperature of 427C.  Which is a lot, but the anti-greenhouse effect is actually really powerful. I tested in SM mode and you can get a safe temperature on mercury with about .7atm of Anti-Greenhouse Gas, 0.1 oxy and 0.3 nitro.

Airless worlds are usually only difficult if they are far from the sun.  It takes a lot of greenhouse effect to make frozen rocks habitable.  Worlds like Venus, with high existing atmospheric pressures are also nearly impossible to colonize. Reducing the atmosphere to useable levels would take several decades for all but the most enormous terraforming project.

[alex_brunius]

Mercury is only slightly more difficult. Mercury has a base temperature of 427C.  Which is a lot, but the anti-greenhouse effect is actually really powerful. I tested in SM mode and you can get a safe temperature on mercury with about .7atm of Anti-Greenhouse Gas, 0.1 oxy and 0.3 nitro.

Why add nitrogen at all to a terraforming project on Mercury? Is that really needed?

[Kaiser (OP)]

there's 3 factors that lead to a breathable atmosphere

-Breathable gas (oxygen for the most part) must be within a certain range, determined by race
-Pressure must be within a certain range, determined by race
-There cannot be ANY dangerous gases

The easiest way to create a breathable atmosphere on a body with no atmosphere is to manufacture Oxygen until you reach the minimum requirement.  For Humans, in version 6 and above, it's 0. 1 atmosphere.   Then switch to creating Nitrogen (say 0. 3atm) Eventually you will be alerted that a breathable atmosphere has been created.

The fly in this ointment is temperature.   Even with a breathable atmosphere, many worlds will be too warm or too cold to be fully habitable.   Humans in version 6 have an ideal temperature of 14C with a deviation of 24C, meaning they can comfortably inhabit worlds with 'surface temperatures' ranging from -10C to 48C.    The thickness of atmosphere and the presence of greenhouse gases can raise the temperature of a planet.   Anti greenhouse gases can lower it.   The Moon has a base surface temperature of -53C, which is fairly easy to deal with.   After you have a breathable atmosphere you can simply add a greenhouse gas until the temperature reaches a comfortable range.

Mercury is only slightly more difficult.  Mercury has a base temperature of 427C.   Which is a lot, but the anti-greenhouse effect is actually really powerful.  I tested in SM mode and you can get a safe temperature on mercury with about . 7atm of Anti-Greenhouse Gas, 0. 1 oxy and 0. 3 nitro. 

Airless worlds are usually only difficult if they are far from the sun.   It takes a lot of greenhouse effect to make frozen rocks habitable.   Worlds like Venus, with high existing atmospheric pressures are also nearly impossible to colonize.  Reducing the atmosphere to useable levels would take several decades for all but the most enormous terraforming project.

Thank you Deadlyshoe, you have been very clear.
a question:

In the case of Mercury, since its colony cost of 16 depends on its very high temperature, could be a good idea starting to cool it adding anti-greenhouse gas using terraforming modules, in order to reduce its colony cost and after put oxygen and nitrogen? I actually have millions of ppl on Mercury, but because the colony cost, they cannot be used for manufactory installations (terraforming for example), indeed should be a good idea to cool it and after add the necessay gases.

[xeryon]

Orbital habitats can be used to man surface installations in this case, which eventually your surface inhabitants can take over the tasks of as soon as they are no longer spending every minute trying to stay alive.

Ship based terraformers could be used too.  Keep in mind the terraforming ships are expensive to build but give you a lot of flexibility in being able to deliver themselves to a work site

[Nibelung44]

what is the minimum pressure you can live with?

[Hawkeye]

If memory serves me right, to be breathable, an atmosphere can not have more than 30% Oxygen. As you need 0.1 atmospheres of Oxygen, about 0.3 atm should be the minimum required.

[Brian Neumann]

On any world where the there is a big temperature effect I would recommend starting off with the greenhouse or anti-greenhouse gasses first.  Get the temperature adjusted to within the your races 2.0 colony cost range for the temperature and then add your breathable gas to suit (Oxygen or Methane).  Once you have a breathable atmosphere you can finish with changing the temperature.  The reason for all of this jumping around is that the colony cost is the worst of temperature, breathability (fixed at 2.00 for unbreathable) and the cost for any poison gasses that are present.  If a gas is present then remove it before adding your breathable gas would be a good idea.

Brian

[joeclark77]

If memory serves me right, to be breathable, an atmosphere can not have more than 30% Oxygen. As you need 0.1 atmospheres of Oxygen, about 0.3 atm should be the minimum required.

More precisely, if you have the minimum 0.1atm of Oxygen, and Oxygen must be less than 3/10 of the atmosphere, then the total atmosphere must be (0.1)*(10/3) or approximately 0.3333atm.  So the non-oxygen gases need to add up to about 0.2333atm.  I usually just round to 0.24atm.

Edit: decimal place error fixed

[Paul M]

Uhm no Hawkeye is correct.  An atmosphere for humans must have 0.1 atm of oxygen and that 0.1 atm must be less than 30% of the total atmospheric pressure.  That means you need 0.34 atm total more or less.

0.1/0.34 = 0.29 or 29% I usually aim for a total pressure of 0.35 atm just to be on the safe side.  So you can say have 0.25 atm nitrogen and then add 0.1 atm oxygen and you will be breathable for humans.

Your math is right but you made a slipped decimal place error.

[joeclark77]

Duh, I got the decimal wrong. Thanks for the correction.  Bottom line is you need 0.24 of the other gases, not 0.30, so that'll save you a little time over Hawkeye's recommendation...