Considering Changes to Terraforming

[IanD]

I like the changes, but is 0.1g too low? The other thing I would like is the inclusion of ice asteroids, which could be tractored and added to the planetary hydrosphere, making the addition of megatons of water in a very short time frame. Ice asteroids then become another valuable resource.
Ian

[MarcAFK]

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.

The large volume of water on earths surface has a massive effect with keeping the climate stable enough for human habitation. Even on earth looking at environments with little to no water cycle, such as deserts, you find daily swings between temperature extremes of 50% celcius in the sun and potentially icy temperatures during the hours immediately before dawn. Not just temperatures but also wind patterns, storms, etc would all be effected, it would be very hard to keep crops or even modern settlements safe in that sort of renviroment. Infrastructure would certainly help.

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.

Simplicity is best of course, with a potential 1000 year atmospheric depletion rate for the moon it's obviously something that's not really significant enoughto bother with. However I was thinking of the addittional oxygen depletion issue for oxide formation, which would be compounded upon if major mining operations were also conducted. If in future the added complexity was considered, these factors together might be significant, and in a similar vein conventional industries might be sources of significant co2 and other toxin production, along with oxygen depletion. But the effect would be minor except in major edge cases, any person running a campaign which would do something like that always has the option of using spacemaster and altering their atmosphere manually.

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).

Seems reasonable, LG worlds have a minimum of 1 so infrastructure is still required, but at that point they'll be pretty cheap to keep topped up with.

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.

This is something I've looked forward to. Perhaps an addittional thing to consider is population growth might be reduced on worlds requiring infrastructure for survival. Surely people would be deterred from having children if theres nothing between you and death but a few sheets of mylar and gold foil.

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.

An interesting addittion to this is that high oxygen levels are toxic for everyone, Co2 breathing plants, methane breathing organisms, even humans to a certain extent if you haven't reduced pressure accordingly. The international space station keeps it's enviroment at sea level pressure and nitrogen content, however EVA is conducted with pure oxygen and about a third atmospheric pressue, which gives a perfectly fine partial oxygen pressure but makes the suit much easier to move around in. Also the reduced pressure lowers how strong it needs to be to survive a vacuum. Pure oxygen is fairly corrosive though so systems which use it continiously might wear out fairly fast. Increased cancer risk might be possible too.

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?

Earth sized bodies have a significantly higher chance of getting good mineral deposits. Maximum population limit is something many people have asked for but I'm not sure every player would agree to it, why go to the trouble of terraforming a planet like venus if it can only hold 10 billion people? Actually one problem is we have no idea how many people you can cram onto a planet, theoretically you could put 100 billion people onto earth, it would suck for them but hey in the grim future there is only coffin sized apartments for everyone, or whatever. One factor is that population growth does actually slow down as a planet gets bigger, I'm not sure at what point or if ever it hits zero though. Maybe small bodies should have a population level where suddely the growth curve starts to increase and hit that cap much sooner than large bodies?
I just ran some tests of population growth, the default start of 500 million gives you 2.52% population growth, 5 billion 1.17%, 10 billion 0.93%, 20 billion 0.74%, 40 billion 0.58%, 80 billion 0.46% 160 billion 0.37 % etc, by 2500 trillion it finally drops down to 1% however attempting to run a full production turn with anywhere over a trillion population causes an overflow and crash, and after 200 billion people population growth actually completely stops. So theres your hard population cap.

[Steve Walmsley (OP)]

I've been considering the questions raised regarding planetary capacity. Given the proposed changes in terraforming, some rules regarding planetary capacity would provide a reason to colonise larger worlds.

The Earth's population is currently seven billion. However, the rate of population growth peaked at 2.1% at four billion, has been dropping since then (now 1.2%) and is projected to reach close to zero around eleven billion

https://ourworldindata.org/world-population-growth/

So if we use that as a basis, we could use the surface area of Earth and four billion people as a baseline for the point beyond which growth rates suffer an increasing penalty. At triple that amount (12 billion for Earth-sized) we have zero growth and start to see overcrowding penalties. I know 70% of the Earth's surface is water but we could hand-wave that away on the basis that planets with a lot of water allow greater population density and it evens itself out.

So using that as a base, we get the following growth rate penalties and max populations:



That doesn't look too bad, with Mars still worthwhile at 3.4 billion max pop, the Moon less than one billion, dwarf planets or medium moons ten of millions, small moons single millions and small asteroid less than one million. That should provide some flavour and give a good reason to terraform larger bodies.

[TheDeadlyShoe]

I like that, especially if its per-body and not per-population;  a neutral pop occupying most of earth would drastically limit population growth, and really provide colonial impetus.

[alex_brunius]

So if we use that as a basis, we could use the surface area of Earth and four billion people as a baseline for the point beyond which growth rates suffer an increasing penalty. At triple that amount (12 billion for Earth-sized) we have zero growth and start to see overcrowding penalties. I know 70% of the Earth's surface is water but we could hand-wave that away on the basis that planets with a lot of water allow greater population density and it evens itself out.

I would prefer if water area also was taken into account to be honest.

There are way too few of the interesting stats from the system information that have any practical ingame / mechanics use at all already as it is!

[MarcAFK]

Seems good, however considering the 1.1% global population growth also takes into account a mortality rate of .8%, who knows what medical advances might do to population growth. Average life expectency is around 70 in wealthy countries, but people do seem to have a limit of about 120, theres genetic modifications possible in the near future. Longer alleles at minimum which is probably the single most important factor causing certain people to live so much longer than the average.
A reduction of pandemic disease, malaria in particular still kills more people then anything else. And then theres war to consider, since Aurora is a war simulator surely that shouldn't be merely taken into account by population growth, rather it should be affected based on what your empire is actually doing. I believe the Earth is technically capable of holding 100 billion, While I'm not sure people would want to keep breeding up to that point but they could sure as hell be crammed into the place.
Would you consider a negative population growth if a body gets overcrowded? Perhaps infrastructure could be used to offset the overcrowding in some way, or perhaps a few research projects could be added which increase maximum population level. I don't think your numbers are a problem though, has anyone played a game where earth ended up with more than 10 billion people, or where you actually needed that many on one body?

[bean]

I like 1, 2, and 4.  3 is OK, but your formula is off.  While the required atmosphere mass will scale with the surface area, it will be inversely proportional to the surface gravity of the planet.  On a lower-gravity world, you need more stuff above you to get a given pressure.  The surface gravity is proportional to both density and radius, so if each terraformer produces a constant mass of atmosphere, you'll see the yearly atmosphere production proportional to density and inversely proportional to radius. 
The gory math behind this can be found at http://aurora2.pentarch.org/index.php?topic=8107.msg91559#msg91559
On the carrying capacity thing, I should point out that technology might well affect that quite a lot, as will other sociological factors.  I suspect that with improved agriculture, you could go quite a bit higher than 12 billion.  The controlling factor there is probably the demographic transition, and it's hard to figure out how that would work in an Aurora-type scenario.  You'd generally want to fight against it in new colonies, but the best social engineering has been pretty much unable to do that on Earth. 

[Haji]

Judging by the responses I seem to be in minority of people who don't like population cap on bodies. This may be because I love creating atypical nations, like an asteroid belt one, where a dozen or so bodies are quite heavily colonized (more than fifty million people each). With the proposed changes making those will be essentially impossible. It also calls into question the very ability to colonize such bodies. What would be the point of settling Vesta or Pallas in the Sol system if each of those can house less than five million people, insufficient to man a mere hundred factories?

Having said that, if the population cap change gets through there are several things to consider. First I'd like this to be a game option that can be turned off. Second since we're talking about habitability, shouldn't tidal lock be included as well, further reducing possible population? The truth is in many campaigns half or even more potential colonies were tidally locked. In addition, what about bodies with infrastructure? Those are, in theory, completely closed and customizable systems, which would imply they can house a lot more people than open air planets. This is especially important in case of underground infrastructure. Also I'd like to point out that small bodies, which could house less than twenty five million, would create some problems for shipping lines, as they would be perpetually locked as destination for colonists, so some changes to that would be needed as well.

Last but not least a change like that just asks for some new technologies. One tree (agriculture maybe?) would serve to increase the planetary capacity for population. Another one (longevity treatments maybe? advanced medicine?) would increase population growth. This may also be a good possibility to add some new installations that result in similar things.

[TheDeadlyShoe]

You could still extend the size of those populations using (newly cheaper) orbital habitats, as well as construction or slave brigades to bolster production.  One multi-faction game I played featured a low-pop faction that relied heavily on construction brigades to make up the difference.   Good point about the shipping lines, although I think VB6 aurora might already even have that capability - shipping lines won't ship pop to colonies hard-capped because of OHs, after all.

Honestly, if you're cramming 50 million people and all the resources you need to support them into rocks that are not Ceres, they're basically Orbital Habitats anyway... :p

[Tree]

Honestly, if you're cramming 50 million people and all the resources you need to support them into rocks that are not Ceres, they're basically Orbital Habitats anyway... :p

If only we could tow small asteroids places and actually turn them into orbital habitats.

[lennson]

Perhaps it would make sense to have technology in the Biology/Genetics tech line that increases maximum population density.

It probably has been mentioned before that this tech category is rather empty and this seems like a reasonable way to expand on it.

edit: Just noticed that Haji has already suggested such technology.

[bitbucket]

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.

Being able to modify hydrosphere? Absolutely yes, but if we're going to tie it to habitability we need to think about this carefully. How much water is enough? How much is too much? Those are some fast and loose questions there, and frankly you can go wrong either way.

Take, for example, some of the fictional worlds portrayed at http://www.worlddreambank.org/P/PLANETS.HTM; it's probable you can have enough water to sustain a biosphere with just a few percent of Earth's oceans. Maybe a 10% hydrosphere coverage would be a better minimum.

On the other hand, how about too much water? I've encountered a number of planets in the game that were 100% covered by an ocean that must've been tens if not hundreds of miles deep, given their large size but low density. If we can add hydrosphere by adding water vapor, then we also need to be able to take it away.

Speaking of biosphere, I'd like to see some consideration of biospheres in habitability. It takes more than air to make a planet come to life. A barren lifeless rock with no atmosphere and the same barren lifeless rock with a breathable atmosphere are both unlivable outside an artificial environment, just that your expected survival time is a minute or two on the former and several days on the latter. I would like to see some indicator of the state of the biosphere as terraforming efforts proceed, even if it's just fluff. What is the aim of terraforming in Aurora? To create new thriving garden worlds, teeming with life? Or are we settling for "just good enough to not need pressure domes," with mostly self-contained cities in barren wastelands, sustained by massive hydroponic farms?

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

This is true, but generally, long-term detrimental effects only start with concentrations over 5000 ppm. Again, this is an issue where you can go wrong with either too little or too much. The current hysteria over climate change has overstated CO₂'s dangers; current research outside the Cult of Globowarmothinkery shows that our current biosphere is starving for CO₂; most plants thrive with CO₂ concentrations around 1000-1200 ppm, and the Earth is 20% greener now than back in the 1970s. If CO₂ concentrations were to drop below 180 ppm, most plant life on Earth would die and our biosphere would collapse. Food for thought there.

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.

Gravity would be a factor, too, as we're basing habitability on partial pressures, and pressure is just a measure of how hard gravity is pulling the gas down on you.

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.

Atmospheric loss is affected by more than just gravity, but solar activity, geological processes, and the planet's magnetic field (or lack of one).

Mars originally had an atmosphere similar to Earth at the dawn of the solar system. Clearly it doesn't now, but how long did it take to get that way? Current evidence suggests it took over a billion years. Venus has probably lost 10 bars of atmosphere to solar wind over 4.5 billion years, for lack of a magnetic field (but it still has 90 bars left). Earth's initial atmosphere was much more Venus-like, but most of that early CO₂ got locked into rocks and buried by tectonic activity.

On anything but a sub-lunar-mass object, atmosphere loss works on longer timescales than your average campaign is going to be concerned about. For the sake of simplicity, just pick a limit like 0.1g and handwave it that civilian low-level background terraforming is maintaining the atmosphere if it wouldn't be stable.

I've been considering the questions raised regarding planetary capacity. Given the proposed changes in terraforming, some rules regarding planetary capacity would provide a reason to colonise larger worlds.

The Earth's population is currently seven billion. However, the rate of population growth peaked at 2.1% at four billion, has been dropping since then (now 1.2%) and is projected to reach close to zero around eleven billion

https://ourworldindata.org/world-population-growth/

So if we use that as a basis, we could use the surface area of Earth and four billion people as a baseline for the point beyond which growth rates suffer an increasing penalty. At triple that amount (12 billion for Earth-sized) we have zero growth and start to see overcrowding penalties. I know 70% of the Earth's surface is water but we could hand-wave that away on the basis that planets with a lot of water allow greater population density and it evens itself out.

Other factors than surface area need to be considered if you're going to impose population caps on planets, regardless of how hard the cap is. For example, how many people would a planet like Earth support if it were, say, covered in an ocean 100 miles deep? Or a tidally locked planet where a third of the surface is a boiling-hot desert and another third is an ice cap with permanent -180° C conditions? (Happens more than you think, probably 97% of rocky planets around red dwarf stars are tidelocked.)

[Zincat]

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.

Absolutely yes. People underestimate how important water is to life on earth. The entire water->water vapor->rain cycle is the very basis of life on earth. Not to mention the effect humidity has on temperature excursion in the day-night cycle. I'll also say, finally at long last. Wanted this for ages

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

Agreed, and another thing I've wanted forever.

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.

Yes, yes, yes. Another thing I've wanted forever because it makes sense.

4) As a corollary to 3), a planet's gravity would determine if any gases could be added.
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.

Putting a 0.1G limit sounds a good compromise to me. Anything lower belongs to the planetoid-class really. And for the sake of actually playing the game, some sort of simplification has to be used.

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.

50% base terraforming reduction sounds a good compromise to me. Maybe it is even too much. Slowing down the base rate of terraforming to  25% would make colonize larger planet wayyy to slow. Not really feasible in the length of a normal Aurora game.

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).

I agree that low gravity should pose some problems even if a planet is terraformed. But I think colony cost 1.0 is too much. My suggestion would be that the colony cost, in case of a terraformed planet with low gravity, be set at 0.5.

I think it's a good, realistic compromise: a planet which IS low gravity, but with a perfectly breathable atmosphere  is four times less "costly to live in" than, basically, a space base on mars. That is what colony cost 2.0 is at the moment.
 
It makes sense to me, considering all the things you don't NEED compared to a pressurized, self reliant space base. Which does not have the luxury of having structural faults, because in cause of a structural problem most of the inhabitants would die. So there has to be so much more redundancy, safety measures and the like. On a terraformed, low gravity world you don't die horribly if something breaks. Hence, 4 times less costs than a pressurized base.

I've been considering the questions raised regarding planetary capacity. Given the proposed changes in terraforming, some rules regarding planetary capacity would provide a reason to colonise larger worlds.

....

So using that as a base, we get the following growth rate penalties and max populations:



That doesn't look too bad, with Mars still worthwhile at 3.4 billion max pop, the Moon less than one billion, dwarf planets or medium moons ten of millions, small moons single millions and small asteroid less than one million. That should provide some flavour and give a good reason to terraform larger bodies.

This is perfect and another change I've waited for a long, long time. Those numbers also seem good for a self-reliant, normal world. They should really be visible before you colonize a planet however. Add another couple of fields to the system and planet view so we know those numbers and can more easily choose what to colonize.
However I have two other proposals to integrate in this.

1) I think that there should be a bonus/malus to population-generated wealth (not to financial centers generated wealth) based on planet size. The reasoning for this is: a larger planet has a lot more "resources" and a lot more "real estate" than a small planet. I'm not talking of minerals here.
A lot of Earth's "riches" come from the impossibly complex ecosystem we have, with all its different environments and biomes. Just think of chemistry, biology, biotechnologies and the like. So, since a terraformed planet is basically a planet where the atmosphere was added and an ecosystem has been imported/developed, it would make sense that a terraformed planet has a bonus/malus to wealth generation based on size, compared to baseline wealth generation on Earth.
This would also imply that any planet which is not terraformed, and so has no ecosystem, would have a malus. And it does make sense, what do these people sell anyway? Space dust? A lot of the normal activities we have on earth are not possible or more costly in a pressurized, relatively cramped environment. So a malus to wealth generation seems logical.

2)
A planet should be allowed to go "beyond maximum". At a cost. Sci-fi is full of examples of such "hive worlds", which a population far beyond its normal limit. The cost of that is that the planet is no longer self-reliant. And that there is so much population that the average wealth generated goes down compared to what it could be on a normally populated, self-reliant world.

My suggestion to model this is that the population limit can be increased by adding infrastructure. I'm not really sure how much would be appropriate though. And that a wealth generation malus should be put in place, progressively increasing as population grows beyond the normal planet limit, because more people have to do with less. Less resources, less space.

[Tanj]

2)
A planet should be allowed to go "beyond maximum". At a cost. Sci-fi is full of examples of such "hive worlds", which a population far beyond its normal limit. The cost of that is that the planet is no longer self-reliant. And that there is so much population that the average wealth generated goes down compared to what it could be on a normally populated, self-reliant world.

My suggestion to model this is that the population limit can be increased by adding infrastructure. I'm not really sure how much would be appropriate though. And that a wealth generation malus should be put in place, progressively increasing as population grows beyond the normal planet limit, because more people have to do with less. Less resources, less space.

Yes, this is what I came here to say. A lot of sci-fi includes heavily over-populated planets that are important for production or resources etc and I would hate to see Aurora lose that as a possibility, both for gameplay and story lore.

Of course, living on an over-populated, industrialised world wouldn't be very pleasant so moral or happiness would likely be affected - in the current Aurora mechanics, falling wealth production would seem a good way of representing this.

I like the idea of adding infrastructure to allow you to go over the planet cap (but not affecting the falling wealth production) AND adding in some new Tech options to artificially increase the planet's total  population cap - advanced farming techniques, improved high-rise infrastructure etc. There could even be new planet buildings to affect this somehow - entertainment centers to keep the populations mind off living in a hell hole, or police-state style buildings for crack downs on dissident populations...

[sloanjh]

3 is OK, but your formula is off.  While the required atmosphere mass will scale with the surface area, it will be inversely proportional to the surface gravity of the planet.  On a lower-gravity world, you need more stuff above you to get a given pressure.  The surface gravity is proportional to both density and radius, so if each terraformer produces a constant mass of atmosphere, you'll see the yearly atmosphere production proportional to density and inversely proportional to radius. 
The gory math behind this can be found at http://aurora2.pentarch.org/index.php?topic=8107.msg91559#msg91559

Agreed on the rate formula being more subtle than simply the surface area (due to weaker pull at surface for lower density planets of the same mass).  But as I tried to say in reply to the post you're citing (although not nearly as clearly as I remember having been ), while the formula you're citing is correct density is not a good parameter to base the formula on because it's not directly tracked by Aurora.  A better formula to use is to stop at the observation that the rate is proportional to surface area and inversely proportional to gravity (the first thing you said above).  So the best formula for Steve to use would be:

time = timeForEarth*(AreaOfBody/AreaOfEarth)*(gravOfEarth/gravOfBody).

John