Considering Changes to Terraforming

[Steve Walmsley (OP)]

I am considering some changes to terraforming for C# Aurora and I am opening those up for comments before I do anything. Bear in mind there is already a major change in terms of low gravity infrastructure that allows many more bodies to be colonised. For example, under the new rules there are ten asteroids in Sol with a colony of 2.00 LG (mainly NEOs), Phobos and Deimos are both colony cost 2.00 LG and Ceres is colony cost 3.78 LG. The Galilean moons are 5.62 but all the other Jovian moons are now 5.62 LG. In my current game, Alpha Centauri has 143 bodies (mostly asteroids) with colony costs of 2.00 or 2.00 LG.

1) Availability of Water. Probably at least 2.00 colony cost with no water, with this reducing to zero once a certain hydrosphere coverage is available (maybe 20%). Water would be created by adding water vapour to the atmosphere. Over time this would condense out of the atmosphere and create a hydrosphere. Exact mechanics TBD.

2) Too much CO2 is harmful. Essentially C02 above fairly minimal concentrations would be a dangerous gas.

3) Small planets are faster to terraform than large ones. The speed at which terraformers add atmospheric pressure would be modified by the surface area of the planet (this would also apply to the hydrosphere coverage), using Earth as the baseline.

4) As a corollary to 3), a planet's gravity would determine if any gases could be added. In real-world physics, small bodies cannot hold an atmosphere because it would drift off into space. The reason for applying this would be avoid asteroids being given an atmosphere in a very short period of time using the rules for 3). The issue here is that a body such as Luna would not retain oxygen or nitrogen in real-world terms due to the low gravity, so I would have to be more generous than reality to keep the game play interesting. Rather than calculate the exact situation, which would be based on escape velocity, temperature and the molecular weight of the specific gas, I would have a fixed boundary, perhaps 0.1G, as the lowest gravity that would retain an atmosphere. This would result in a lot of low gravity bodies that could be colonised at 2.00 LG (which can't currently be colonised) but which would never improve beyond that point because they would not retain the atmosphere required for terraforming.

The combination of 3) and 4) would mean a significant disparity in how fast worlds could be terraformed, but not to extremes. For example, compared to Earth, Mars would be terraformed 3.5x more quickly, Ganymede 5.9x more quickly and Luna 13.5x more quickly. In fact, it would probably make sense to slow down the base rate of terraforming to the middle of that range, aiming for perhaps 25% - 50% of current rates. In the case of 25%, the rate of terraforming vs current would be:

Earth: 25% of current speed
Mars: 88% of current speed
Ganymede: 147% of current speed
Luna: 337% of current speed.

Large planets would take a suitably long time to terraform, with small planets and moons (that are still large enough to retain atmosphere) being terraformed relatively quickly. Depending on how much effort is required for the hydrosphere element I could make the reduction 50% instead on the assumption that the additional water vapour would also act to slow down the process.

Thoughts?

[Haji]

1) Availability of Water. Probably at least 2.00 colony cost with no water, with this reducing to zero once a certain hydrosphere coverage is available (maybe 20%). Water would be created by adding water vapour to the atmosphere. Over time this would condense out of the atmosphere and create a hydrosphere. Exact mechanics TBD.

Lack of water is nowhere near as problematic for life as lack of an atmosphere, especially since recycling is available, so I think lack of water should require infrastructure, but nowhere near as much (0.5 or so for completely desert planet). At the same time if we can actually add water to the planet than the exact infrastructure cost is not really an issue.

2) Too much CO2 is harmful. Essentially C02 above fairly minimal concentrations would be a dangerous gas.

As long as we can still add safe greenhouse gases to the atmosphere, I don't really mind this change one way or the other.

4) As a corollary to 3), a planet's gravity would determine if any gases could be added. In real-world physics, small bodies cannot hold an atmosphere because it would drift off into space. The reason for applying this would be avoid asteroids being given an atmosphere in a very short period of time using the rules for 3). The issue here is that a body such as Luna would not retain oxygen or nitrogen in real-world terms due to the low gravity, so I would have to be more generous than reality to keep the game play interesting. Rather than calculate the exact situation, which would be based on escape velocity, temperature and the molecular weight of the specific gas, I would have a fixed boundary, perhaps 0.1G, as the lowest gravity that would retain an atmosphere. This would result in a lot of low gravity bodies that could be colonised at 2.00 LG (which can't currently be colonised) but which would never improve beyond that point because they would not retain the atmosphere required for terraforming.

This is a very interesting change. However I'd like to point something out - if my memory serves Luna could hold an atmosphere, but only for a short period of time, geologically speaking. Which translates to hundreds, potentially thousands of years  during which the atmosphere could be retained. As such I think bodies with reasonable gravity (0.1g or more) should be able to retain atmosphere over the typical gameplay session. Asteroids are another matter entirely and in this case I agree that they could not hold gases for any reasonable period of times.

I'd like to also add two things. First since a player can create atmosphere (and seemingly from nothing as well) there is no reason he couldn't keep replenishing it. As such if you really want to include atmosphere loss in a game, you can just program loss of gases that can be combated. In short on small bodies, like Luna, you would have to keep some terraforming installations on line, all the time, so they can keep replenishing the atmosphere, keeping the world habitable.

Second there exists an idea of paraterraforming. To put it simply by covering an entire planet in domes (or one superdome) you can effectively create a living breathing world, from which an atmosphere would not escape. Whether or not this is something you want to program in, I don't know. I would imagine this to be some sort of very expensive project that would result in significantly lower infrastructure cost or something similar.

[Steve Walmsley (OP)]

I think for the purposes of retaining gases, rather than tracking the loss of atmosphere, I would just have a boundary that was needed for terraforming to be effective. It would just be a rule (using gas retention as the reason) that you couldn't terraform anything with gravity lower than 0.1G.

[TheDeadlyShoe]

1.) Studying the system info panel, it seems to me this would primarily be a feature of terraforming moons and small worlds. Those are typically much smaller than current planets, so you'd end up with a planet that is much easier to terraform speed-wise (owing to 3) but has more steps to complete terraforming so it takes longer.  This is not necessarily a bad thing, just noting these aspects are at tension. :^)
 
Might be interesting stepping away from the 2.00 hard limit for water, since that's atmosphere's shtick. IE a world with a breathable atmosphere but no hydrosphere could have a 1.00 colony cost minimum. Or water could act like a modifier, lack of which adds +1 to colony cost- thus a planet with neither atmosphere nor water would have 3.00 colony cost, and you could add water first to bring it down to 2 or atmo to bring it down to 1.

3 - if large worlds are going to be more difficult to terraform, perhaps size should also play a component in severity of bombardment penalties and/or population growth curve?


I am a big fan of 4.

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How does this play out in the intersection of <can retain atmosphere> but <LG colony>? Say I'm running a 70% gravity variance so all the Galilean moons are LG - then I terraform Ganymede to be a livable world with zero basic colony cost?

[Steve Walmsley (OP)]

How does this play out in the intersection of <can retain atmosphere> but <LG colony>? Say I'm running a 70% gravity variance so all the Galilean moons are LG - then I terraform Ganymede to be a livable world with zero basic colony cost?

Good question. For a low gravity colony, I think there should be a minimum colony cost. Even if the air is breathable, some form of gravity assistance would still be needed. Perhaps LG worlds are always at least colony cost X, so (in the above situation) you could reduce the colony cost to X by improving the temperature, but the low gravity prevents any improvement beyond that.

X = 2.00 seems the obvious choice, but that would mean there was no point making the air breathable or adding water, so perhaps 1.00 is a more interesting option (essentially the low gravity element of the LG infrastructure without the life support requirement).

[Nori]

These changes sound good, though I feel like there should be a compelling reason to colonize a larger planet if they take longer to terraform. 
I don't recall seeing there being a population cap for a planet, but is something like that possible? Larger bodies can hold larger populations? Or as TheDeadlyShoe said, maybe larger planets just grow a lot faster?

[83athom]

1) Availability of Water. Probably at least 2.00 colony cost with no water, with this reducing to zero once a certain hydrosphere coverage is available (maybe 20%). Water would be created by adding water vapour to the atmosphere. Over time this would condense out of the atmosphere and create a hydrosphere. Exact mechanics TBD.

This is a long awaited change that I think most would agree with. However, the point where the hydrosphere kicks in to "perfect" if really up for debate. On one hand, you only need as much water to survive. On the other, a massive surplus of usable water is best for agricultural needs. Maybe instead of the hydrosphere directly affecting suitability, maybe it could be a modifier to the percentage of population needed for agriculture (to simulate water miners, water transports, etc on a planetary scale).

2) Too much CO2 is harmful. Essentially C02 above fairly minimal concentrations would be a dangerous gas.
3) Small planets are faster to terraform than large ones. The speed at which terraformers add atmospheric pressure would be modified by the surface area of the planet (this would also apply to the hydrosphere coverage), using Earth as the baseline.

Agreed.

4) As a corollary to 3), a planet's gravity would determine if any gases could be added. In real-world physics, small bodies cannot hold an atmosphere because it would drift off into space. The reason for applying this would be avoid asteroids being given an atmosphere in a very short period of time using the rules for 3). The issue here is that a body such as Luna would not retain oxygen or nitrogen in real-world terms due to the low gravity, so I would have to be more generous than reality to keep the game play interesting. Rather than calculate the exact situation, which would be based on escape velocity, temperature and the molecular weight of the specific gas, I would have a fixed boundary, perhaps 0.1G, as the lowest gravity that would retain an atmosphere. This would result in a lot of low gravity bodies that could be colonised at 2.00 LG (which can't currently be colonised) but which would never improve beyond that point because they would not retain the atmosphere required for terraforming.

A limit on the gravity for terraforming makes sense. But how about a tech/installation fairly down the line, like a planetary shield, that could hold in an atmosphere on low gravity bodies.

The combination of 3) and 4) would mean a significant disparity in how fast worlds could be terraformed, but not to extremes. For example, compared to Earth, Mars would be terraformed 3.5x more quickly, Ganymede 5.9x more quickly and Luna 13.5x more quickly. In fact, it would probably make sense to slow down the base rate of terraforming to the middle of that range, aiming for perhaps 25% - 50% of current rates. In the case of 25%, the rate of terraforming vs current would be:

Earth: 25% of current speed
Mars: 88% of current speed
Ganymede: 147% of current speed
Luna: 337% of current speed.

Large planets would take a suitably long time to terraform, with small planets and moons (that are still large enough to retain atmosphere) being terraformed relatively quickly. Depending on how much effort is required for the hydrosphere element I could make the reduction 50% instead on the assumption that the additional water vapour would also act to slow down the process.

I like the thought of making terraforming in general slower while modified by gravity/size. It makes the perfect planets you come across more valuable while making close but not enough ones a project for the future. However the example given may be a bit too extreme with a change in size.

[MarcAFK]

Oh boy, this is going to be one of those mega threads. Firstly I'm glad you've brought this up and support the changes proposed so far, perhaps with some minor quibbles. I don't want too much added complexity but obviously the current system is a little bit too much handwavium.
1) Good idea, perhaps frozen water should also be taken into account when a planet reaches a suitable temperature? It would require determining how much surface various bodies in the solar system has that would actually be liberated once thawed. I think the moon has a fairly large surface water deposit, but certainly not enough to reach 20%, perhaps low gravity bodies with the minimum 2 colony cost should actually have their cost increased higher than 2 by factors which on other worlds only raises cost to 2? For instance low water availibility causing a cost of 3 or 4 on the moon rather than 2. Simple addition of 1 extra colony cost on top of all other factors for these bodies is probably easiest.
2) The mechanics of this should be interesting, At around 0.5%-1%  side effects start to develop, causing symptoms of intoxication affecting memory, motor skills, critical thinking etc, above 5-7% for short periods can cause unconsciousness. Long term exposure to above 10% Co2 is generally fatal, though I suppose genetic modification might allow higher percentages. A reduction in wealth and industrial production at levels over 1% seems like a good idea to me, with population growth being affected when concentration gets high enough.
3) Makes sense, however there is another factor affecting small bodies mostly, and certain large bodies also. If a planet has never had an oxygen atmosphere then the surface will be covered in highly reactive compounds, like iron, which will oxidize as you add oxygen to the atmosphere. I read somewhere than you might need 3 times as much oxygen to be added to the moon before it will become breathable due to surface rust forming. Mars doesn't suffer this problem as It had significant oxygen as it's crust was forming causing surface iron to already be oxidized.
4) I can't find relevant numbers right now, but I've heard anywhere between 100-1000 years for a terraformed atmosphere to be stripped off the moon by solar wind. One interesting factor is that as gas escaped from a moon at least half of it will become part of a torus in orbit of the parent body, some will impact back into the satellite as it passes through, and a large proportion will fall back into the atmosphere of the parent.
Going by a depletion time of 100 years for the moon you might add a mechanic that 1% of gasses escape per year, so terraforming facilities would be needed to keep the atmosphere topped up. It would be frustrating to need to manually swap facilities around between adding nitrogen, oxygen, greenhouse gasses etc. So add a mechanic that allows existing facilitys to simply offset their production against lost gasses.
I'm in favor of slowing down terraforming, it really should be an insanely difficult process. We lucked out with mars being right next door though.

[Steve Walmsley (OP)]

I've been playing around with dangerous gases. At the moment, a gas counts as dangerous (for colony cost purposes) when it comprises 0.01% of the atmosphere (about 100 ppm).

For C# Aurora I have changed this so different gases require different concentrations before becoming 'dangerous'. This is based on information from the CDC and a couple of other sources. Halogens such as Chlorine, Bromine or Flourine are the most dangerous at 1 ppm, followed by Nitrogen Dioxide and Sulphur Dioxide at 5 ppm. Hydrogen Sulphide is 20 ppm, Carbon Monoxide and Ammonia are 50 ppm, Hydrogen, Methane (if an oxygen breather) and Oxygen (if a Methane breather) are at 500 ppm and Carbon Dioxide is at 5000 ppm.

These gases are not lethal at those concentrations but are dangerous enough that infrastructure would be required to avoid sustained exposure.

[TheDeadlyShoe]

i was actually googling earlier to check if carbon dioxide was theoretically dangerous for methane breathers, but got surprisingly little information. Most of the scientific-ish items I skimmed skirted the topic, focusing more on methane-breathing organisms on earth (that also use oxygen so ?) or on more firmly grounded theoretically-possible biologies.  The fiction stuff hadn't considered the topic.  I gave it up since i wasnt sure different dangerous gases for different breathers sounds like it coulda been effort to do anyway~~

Did find some nifty hypothetical aliens that explode if you throw water on them.

[Triato]

Thanks for the update.  If we are to have several asteroid colonies with no armosphere,  please remove the 25 million minimum population necesary to flag the colony as stable (stop inmigrants)

[Garfunkel]

Anything that makes terraforming more complex is a plus in my book.

1) Sounds good.

2) Yes.

3) Sensible.

4) Good change. I would put the limit little higher - it always struck me little odd that we could turn Luna into a tropical paradise pretty damn easily.

[Maltay]

This may be an uninformed question.  However, if small planetary bodies (e.g., moons of sufficient size) are faster to terraform than large planetary bodies (e.g., a planet like Mars), then why would the player bother terraforming large planetary bodies short of minerals?

Is there a correlation between the size of the planetary body and mineral generation or accessibility?  If there a maximum population that a planetary body can hold based on size?

[alex_brunius]

This may be an uninformed question.  However, if small planetary bodies (e.g., moons of sufficient size) are faster to terraform than large planetary bodies (e.g., a planet like Mars), then why would the player bother terraforming large planetary bodies short of minerals?

Is there a correlation between the size of the planetary body and mineral generation or accessibility?

Pretty sure larger body = higher chance of more minerals in 7.1 Aurora

If there a maximum population that a planetary body can hold based on size?

Not in 7.1 Aurora.

But I think you make an excellent point.

What if each body had a "population capacity" which is based on available surface area - hydrosphere coverage. Any population above this would basically count as requiring colony cost 1 infrastructure to not have population growth halt or turn negative.

This would make it worth it to terraform larger bodies I think.



Another related thing I posted previously in suggestions a few years ago is that it would make sense if the population capacity would not reach max until you reached optimal conditions. Right now there is no point in keeping terraforming temperature/oxygen once you crossed the absolute minimum required point, which kind of doesn't make sense... ( in reality each person have a different tolerance and some areas of the planet would be warmer/cooler higher/lower oxygen to suit your needs ).

What would be really cool is if when you reached the minimum tolerance, "population capacity" started growing from 0, linearly up towards the maximum which is achieved when oxygen, temperature and such reach the optimal value.

[TheDeadlyShoe]

Planetary attributes do have a significant impact on mineral rolls (larger - more likely, higher quantity, lower accessibility), but no there's no real particular reason to go for a New Earth over a Nice Moon.   If you get lucky in mineral rolls for the Solar System, the gameplay reason for extrasolar colonization is ruins and anomaly research bonuses - that and military basing, though you don't technically need real colonies for that.

The principal issue with population caps is that they would have to be very low to make a meaningful impact to Aurora gameplay. The normal starts is 500 million after all - a large nation, not planetary-scale. 

In current aurora, I play with the house-rules of not establishing a colony without a purpose (no 'wealth colonies') and 'hard terraforming' - no modules, no safe gases, terraforming stations must be built on site, and I pretend they cost 10x what they do.  It makes good worlds much more valuable.