Terraforming Jupiter's Moons

Spatula · 2007-05-29 11:41:35

I regretfully say that it's unlikely anything in the outer solar system, even Jupiter's moons, can be terraformed. These cryogenic bodies receive a mere 3.5% of the sunlight we get on Earth, and while they have other redeeming qualities over Mars and Venus, when plants can't photosynthesize on the surface, you run into some huge sustainability problems.

This is unfortunate, since Ganymede in particular has pretty good credentials for holding a thick atmosphere. It produces its own magnetic field, which is enough to shield it from Jupiter's magnetic influence, which also shields it from the Sun's. If Ganymede, or Europa or Callisto for that matter, were terraformed, it would result in an ocean world, with hundreds of times the water depth of Earth. The variety of organisms that could thrive in a low-gravity water environment is staggering.

So here's a thought: what if the geological activity inside the moons is enough to sustain chemotrophic bacteria that can replace CO2 with O2? Building thick atmospheres aside, would it be possible to design an ecosystem off of this?

Interesting to think about, even if we decide it wouldn't be economic to try.

StarDreamer · 2007-05-29 14:33:52

Either such an ecosystem will work at "Europa as it is" (unterraformed) or it will not work out there (Jupiter) at all. In other words, the environment you are describing -- a waterworld, with water depth hundreds the times of depth on Earth, -- this exists on Europa right now. So, if life has not evolved in that ocean already, of its own accord, then that should make us think twice about the viability of the project. If panspermia is correct, then more than enough time has lapsed already for something to get going. If Europa has not evolved endemic life, then our next step should be to introduce some likely candidates from Earth into that environment to see how they make out -- jellyfish, plankton, archaea, protozoans, etc. If the water is anaerobic, then they are out of luck too. If life cannot hold its perch on Europa even with a jumpstart from Earth's oceans, then I don't know how we could rationalise the effort required to make a "bigger better" Europa on Ganymede.

~~ Bryan

Martian Republic · 2007-05-29 15:24:28

With present technologies, I don't see anything past Mars having any serious colonization going on in the near term. But, assuming that we are able to build fusion and go on into anti-matter energy sources, then that would open up a whole new possibility of colonization of the moons of Jupiter and beyond. A colonization of Mars would develop the technologies that we would need to make an attempt at colonizing the moons of Jupiter possible and also put the infrastructure into place to support that colonization project too. It will would probably take a hundred years or more to be in a position to start that colonization of the Moons of Jupiter even then. Even with a Mars colonization program, we would have to develop new technologies and build the infrastructures to do it even in a fifty year time frame or so.

Larry,

nickname · 2007-05-29 17:47:32

I think all the worlds out there are ready for us.
We don't really need to teraform any of them to set up home.
We need not rely on the sun for plant life to feed ourselves.

We can bring light, heat, power sources, seeds and equiptment then simply teraform the structures we make.
Either on the surface or bellow it if radiation or climate conditions dictate.

I can see a very good reason to go to Titan, a fuel depot with an unlimited supply.
A few water ice worlds around Jupiter are also great targets to set up shop.
But who will be using the fuel and water?
No real destination exists to use fuel or water, so they will have to justify themselves as destinations.

It might be more of a question of why go to them, what do they have to offer that would make setting up home a useful idea.

Mars is pretty simple to justify as an expansion and saviour of all life if a disaster should strike Earth, and the search for ancient Martian life a very good second reason.
Beyond Mars we either need good returns or good reasons.

X · 2007-05-29 20:22:36

Europa sounds so great, and I've got to think that even if it lacks native life it could be seeded easily from earth. Given how many species live only between certain depth ranges we could even possibly introduce earth species without a threat to native species if any exist and things turn out right as to where they live.

Does anyone know if there's any information on the composition of the interior of Europa though? Is it a sphere of water below the ice, or is there a metallic core? If so is it solid or molten?

Even lacking native life and a course of chemicals for a chemosynthetic species at the bottom of the pyramid I think we could maybe slowly get things going. Dump enough biological waste into the water, and then build your ecosystem on some filter feeder like clams. That'd likely take a long time though.

There's a topic on the human missions board I think about colonizing earth's oceans that might have some applicability.

Antius · 2007-05-30 05:32:12

Actually, the sunlight intensity at Jupiter's orbit may be sufficient to allow at least some plant life to survive and may therefore support a limited ecosystem.

Jupiter's average distance from the sun is 5.46AU. The average sunlight intensity is therefore 45 watts/m2. On the equator of a terraformed Jovian moon, sunlight intensity would be perhaps 40 watt/m2 at midday, outside of Jupiters shadow. This is typical of Northern European mid-winter illumination levels. There are plenty of plants that will grow at these light-levels, if you are able to keep their roots warm. The rate of photosynthesis and therefore rate of growth will be reduced. This is inconvenient, but is not a show-stopper.

Using super greenhouse gases, it may be possible to keep the atmosphere of a terraformed Jovian relatively warm. In addition, the waste heat from a colony's nuclear/fusion reactor could be used to warm greenhouses full of food crops. The weak sunlight could be supplimented by artificial light, targeted at very specific and optimised frequencies for plant growth.

Many species of photosynthetic algae will thrive at very low sunlight levels, if provided with a liquid medium and sufficient nutrients. Genetic engineering could do wonders in this area and it is not difficult to imagine that a range of algal species could serve as the base for a larger food chain, just as plankton and complex land plants do on Earth.

I am still fishy about this idea of a global ocean world. It would appear to me that any useful meteoritic materials, which are no doubt abundantly available in the crusts of Jovian satellites, would sink to the core and be lost forever. There is also the crucial issue of recycling carbon, nitrogen and nutrients of any dead organisms that sink to the bottom of a 100 - 1000km deep ocean. I hate to imagine the sort of storms that might be generated in a global ocean that deep.

Antius · 2007-05-30 05:39:27

Europa sounds so great, and I've got to think that even if it lacks native life it could be seeded easily from earth. Given how many species live only between certain depth ranges we could even possibly introduce earth species without a threat to native species if any exist and things turn out right as to where they live.
Does anyone know if there's any information on the composition of the interior of Europa though? Is it a sphere of water below the ice, or is there a metallic core? If so is it solid or molten?
Even lacking native life and a course of chemicals for a chemosynthetic species at the bottom of the pyramid I think we could maybe slowly get things going. Dump enough biological waste into the water, and then build your ecosystem on some filter feeder like clams. That'd likely take a long time though.
There's a topic on the human missions board I think about colonizing earth's oceans that might have some applicability.

As a target for human colonisation, Europa strinkes me as the least promissing of all of the Jovians. It is relatively small, has a young and therfore mineral depleted icy crust and is right in the middle of Jupiter's radiation belts. Callisto is probably the most appealing target, Ganymede a distant second.

noosfractal · 2007-05-30 05:59:26

One thing with Jupiter's moons is the deadly radiation - 10 minutes unshielded is enough to kill a human.

Europa is the worst off. Until you've got lots of well designed atmosphere, you're probably going to be living under the water.

You might want to think about Titan first. Saturn's local environment is relatively benign. Use large mirrors/Fresnel lenses to up your solar wattage.

Antius · 2007-05-30 07:17:27

One thing with Jupiter's moons is the deadly radiation - 10 minutes unshielded is enough to kill a human.
Europa is the worst off. Until you've got lots of well designed atmosphere, you're probably going to be living under the water.
You might want to think about Titan first. Saturn's local environment is relatively benign. Use large mirrors/Fresnel lenses to up your solar wattage.

Lasers? You would need a very impressive laser to illuminate an entire world and a wacking huge amount of electric power. I just can't see that being a very practical solution.

As for using lenses, the scale of the engineering required would be similarly huge. Sunlight intensity at Titan's distance from the sun is 1% that of earth and the lense would need to be continuously realigned as Titan orbited Saturn and Saturn orbited the sun.

It would probably be much easier to build a fusion reactor on the surface and artificially illuminate areas that have been heated with wasteheat from reactors.

In any event, Titan's existing hydrocarbon atmosphere would appera to be more of a hindrance than a help. Rhea, Japetus and Dione are also promissing potential candidates.

Antius · 2007-05-30 08:16:48

It sounds ridiculous, but it would appear no less possible than terraforming Jupiter's other large moons. Amalthea has the dimensions 250x146x148km and its surfcae gravity is 0.02m/s2. This is 1/500th of Earth's gravity. The column density of the atmosphere would therefore need to be 5000tonnes/m2 for a 1bar average surface pressure. the total mass of the atmosphere would 5x10(17)kg - fully a quarter the mass of the satellite! The escape velocity of Amalthea is just 50m/s, so the atmosphere would escape very rapidly without a magnetic field holding it in place.

The views of Jupiter would be stunning!

X · 2007-05-30 08:56:52

One thing with Jupiter's moons is the deadly radiation - 10 minutes unshielded is enough to kill a human.

Have a way to heat your landing craft's "skin" and melt your way down into the ice. Between it, the water you leave between yourself and the bottom of the ice, and your habitat you should be protected from most of the radiation.

Europa is the worst off. Until you've got lots of well designed atmosphere, you're probably going to be living under the water.

That as my plan all along. There have been folks who got by fairly well on diets of mostly seafood. I mean you're probably stuck for a while anyways which might cut down on your potential colonist base, but maybe you could place a massive lattice work in the ice over time to shore up a section of ice to act as a permanent surface.

Your right though its probably a crazy idea.

Spatula · 2007-05-30 09:08:52

One thing with Jupiter's moons is the deadly radiation - 10 minutes unshielded is enough to kill a human.
Europa is the worst off. Until you've got lots of well designed atmosphere, you're probably going to be living under the water.
You might want to think about Titan first. Saturn's local environment is relatively benign. Use large mirrors/Fresnel lenses to up your solar wattage.

I never really saw the appeal of Titan. The nitrogen atmosphere is about all it has going for it. It's too cold, too inert. Plus, it's a very pristine environment, with the 3-phases of hydrocarbons on the surface.

I'm going to have to agree that Callisto is probably the best candidate in the Jupiter system for colonization. It's far enough from Jupiter to reach fairly easily, without having to use a lot of fuel to get inside the steep gravity well that the other moons are in. Gets no radiation from the planet too.

Ganymede might be a better terraforming candidate for the long term. Not that it's that great of one to begin with. Radiation is not a problem there either. We'll see.

noosfractal · 2007-05-30 09:31:34

Lasers? You would need a very impressive laser to illuminate an entire world and a wacking huge amount of electric power. I just can't see that being a very practical solution.

Maybe down the road a bit. We'll need very high power lasers to push interstellar probes.

As for using lenses, the scale of the engineering required would be similarly huge. Sunlight intensity at Titan's distance from the sun is 1% that of earth and the lens would need to be continuously realigned as Titan orbited Saturn and Saturn orbited the sun.

I think the lens close to the Sun and the lens at Saturn-Sun L1 can be done, but the final mirror to chase Titan would be a pain. I'm hoping that the lenses and mirrors etc can be constructed using plasma rather than a solid as in ...

Optical plasma devices
http://www.google.com/patents?id=QnV8AAAAEBAJ

... but it would still be a major effort.

It would probably be much easier to build a fusion reactor on the surface and artificially illuminate areas that have been heated with wasteheat from reactors.

You're very likely right. All the buzz around alternative reactor designs has me quite optimistic about fusion at the moment.

In any event, Titan's existing hydrocarbon atmosphere would appear to be more of a hindrance than a help. Rhea, Japetus and Dione are also promising potential candidates.

The hydrogen cyanide is a bit of a worry - it’s lethal at 300 ppm – but with all that nitrogen and water to make oxygen, it’ll probably be the first extraterrestrial body to have an earth-like atmosphere.

StarDreamer · 2007-05-30 09:54:00

Someone once said there are two kinds of people in this world -- those who divide everyone into two kinds of people and those who do not.

So let's talk about planets and moons. There are two kinds of world in this solar system -- those with atmospheres and those without. Earth, Venus, Titan and Mars are With. Luna, Ceres and the Jovian Moons are Without. Each kind presents its own group of problems, but, on the whole, With is a lot easier to work with than Without. If we insist on going Without, then let's begin with Luna, but, if we cannot get Luna right, then there's no sense in talking about Ceres or Europa or Ganymede or Callisto. Mars in its present condition is nearly Without, so if Mars is insurmountable, then all those truly Without are idle dreams.

In a related kind of way, there are two other kinds of world in this solar system -- those with heat and those without. Venus, Earth and Mars are With. Luna, Ceres, the Jovians and Titan are all Without, sometimes as a function of being airless and sometimes as a function of distance. Again, on the whole, With is a lot easier to work with than Without.

Let's use Earth as our analogy. What are the populations of Indonesia, India, Zaire and Brazil? Nearly two billion? Then what are the populations of Greenland, Spitzbergen and Antarctica? Some like it hot, but few love it cold. If Terran lifeforms have shown diminished attraction to polar conditions on Earth, then they will never take to those frigid little worlds out in space. Mars is at the limit in that direction, though under the ice on Europa is a slim possibility. Likewise, there is a greater variety of life under great pressures at the bottom of the sea and even deep within the rocks of the crust than there is floating in our atmosphere at low pressure. Heat and pressure quicken the pace and rhythms of life. Without these, the chemical reactions that power life slow and stop.

~~ Bryan

noosfractal · 2007-05-30 11:42:04

I think Antius is right and it'll come down to economics. So then the question changes to something even more illdefined than terraforming: how will companies profit from space? Under what conditions does terraforming save them money?

When considered this way I think Ceres has a relatively high probability of being terraformed. It is small enough that terraforming won't take forever (like Mars) and it is in the asteroid belt which will be a source of low delta-v (relative to, say, Earth-Moon L1) material for ... well, a long long time. Zubrin's low gravity advantage argument for Mars applies 10 fold for Ceres, and Ceres itself is a source of a valuable commodity - low delta-v water.

Even if Mars is technically easiest to terraform, it may have a difficult time funding it.

Spatula · 2007-05-30 14:48:57

I'm pretty sure Venus would be easier to terraform than Mars. Seeing as it lacks water, which is cheap, and Mars lacks nitrogen, which is quite expensive.

And as for the moon thing, it's not so cut-and-dried. Earth's moon has no ocean, and no atmosphere. Titan has practically no sunlight. Ganymede and Europa lack atmospheres, and Callisto lacks internal geology. They all have their own problems.

noosfractal · 2007-05-31 00:43:27

I'm pretty sure Venus would be easier to terraform than Mars. Seeing as it lacks water, which is cheap, and Mars lacks nitrogen, which is quite expensive.

You're definitely not going to be getting terraforming materials from Earth, even with a space elevator. The most likely source for volatiles in my mind is comets and icy asteroids from the outer solar system, so ... what's your basis for declaring water cheap and nitrogen expensive?

Antius · 2007-05-31 00:58:50

I'm pretty sure Venus would be easier to terraform than Mars. Seeing as it lacks water, which is cheap, and Mars lacks nitrogen, which is quite expensive.
And as for the moon thing, it's not so cut-and-dried. Earth's moon has no ocean, and no atmosphere. Titan has practically no sunlight. Ganymede and Europa lack atmospheres, and Callisto lacks internal geology. They all have their own problems.

Terraforming Venus would be a nightmare of a project. How exactly do we dispose of a carbon dioxide atmosphere with a column density of 1000tonnes per square metre?

To introduce sufficient water to Venus would require the equivelent of several large kuiper belt objects, all of which would presumably need to cross Earth's orbit to get there.

Even after terraforming, the planet would still be unbearably hot, with the surface temperature teetering around the boiling point of water in equatorial regions. Then you have to deal with the fact that Venuses day-length is roughly comparable to its year (~250days).

Given Venus's hostile environment, relatively deep gravity well and general lack of anything exceptional that it might export, I would anticipate that this will probably be a deadzone for future human colonization.

Antius · 2007-05-31 01:12:25

Someone once said there are two kinds of people in this world -- those who divide everyone into two kinds of people and those who do not.
So let's talk about planets and moons. There are two kinds of world in this solar system -- those with atmospheres and those without. Earth, Venus, Titan and Mars are With. Luna, Ceres and the Jovian Moons are Without. Each kind presents its own group of problems, but, on the whole, With is a lot easier to work with than Without. If we insist on going Without, then let's begin with Luna, but, if we cannot get Luna right, then there's no sense in talking about Ceres or Europa or Ganymede or Callisto. Mars in its present condition is nearly Without, so if Mars is insurmountable, then all those truly Without are idle dreams.
In a related kind of way, there are two other kinds of world in this solar system -- those with heat and those without. Venus, Earth and Mars are With. Luna, Ceres, the Jovians and Titan are all Without, sometimes as a function of being airless and sometimes as a function of distance. Again, on the whole, With is a lot easier to work with than Without.
Let's use Earth as our analogy. What are the populations of Indonesia, India, Zaire and Brazil? Nearly two billion? Then what are the populations of Greenland, Spitzbergen and Antarctica? Some like it hot, but few love it cold. If Terran lifeforms have shown diminished attraction to polar conditions on Earth, then they will never take to those frigid little worlds out in space. Mars is at the limit in that direction, though under the ice on Europa is a slim possibility. Likewise, there is a greater variety of life under great pressures at the bottom of the sea and even deep within the rocks of the crust than there is floating in our atmosphere at low pressure. Heat and pressure quicken the pace and rhythms of life. Without these, the chemical reactions that power life slow and stop.
~~ Bryan

This makes sense. I know that many would argue that an icy terraformed world has long-term security advantages over a thin-shelled habitat, but in the short to medium term, an O'Neill type habitat is overwhelmingly attractive, in terms of initial cost and living conditions. It would appear to offer far more in terms of value for money. They are also incremental - you can buildf them one at a time, eventually building up a massive amount of land. Contrast this to any terraformed world, whose land will not be available for habitation until the enormous task of terraforming is completed, probably centuries in the future.

It is rather hard for me to imagine, what sort of society would go to so much cost and expense creating what is sure to be a cold and miserable little planet. It is easier to imagine an incremental terraforming approach on Mars, where the atmosphere would be initially thickened to provide cosmic ray shielding and could be accomplished relatively easily, simply by pumping CFCs into the existing atmosphere. But most other worlds (the jovians, satellites of saturn, uranus, neptune, pluto and the TNOs) will always be cold, miserable and rather unproductive even after full terraforming is complete. Mars isn't the only candidate, but it appears to be the only one that offers value for money.

nickname · 2007-05-31 04:57:19

Antius,

100% in agreement with the outpost now, built to colony later, teraform much later from the people that create the colony on Mars.

Sort of follows how the USA was settled.
Small group of pioneers settle and build thing up, they create towns that turn into cities.
When the technical ability and will is ready for them to teraform it they will.

The CFC's on Mars are the way to go it think also.
That and a few water ice asteroids when the time is right.

Beyond Mars i think just science outposts at best.

noosfractal · 2007-05-31 05:11:40

One of the problems is that some terraforming options are only really available before major settlements are established. For example, if you want to smash ammonia asteroids into Mars, you should probably do it when there are no people there.

Also, say you wait 200 years before raising the temperature enough to melt ice and create oceans. What about the people who own land (now for generations) in the areas that will be flooded? A dozen special interests will develop over 200 years that will lobby to halt the deluge. Buying them out might be your biggest terraforming expense.

Antius · 2007-05-31 05:34:16

One of the problems is that some terraforming options are only really available before major settlements are established. For example, if you want to smash ammonia asteroids into Mars, you should probably do it when there are no people there.
Also, say you wait 200 years before raising the temperature enough to melt ice and create oceans. What about the people who own land (now for generations) in the areas that will be flooded? A dozen special interests will develop over 200 years that will lobby to halt the deluge. Buying them out might be your biggest terraforming expense.

True. You would probably end up displacing entire cities, maybe even entire new nations!

Some form of terraforming would appear desirable at an early stage on Mars. The present atmosphere is too thin to provide any plausible shielding against cosmic rays or solar flares and may even aggrevate the situation by breaking down into secondary particles.

Also, thickening the atmosphere could be accomplished relatively easily, with half a dozen CFC producing nuclear-powered factories on the surface. As soon as major flourine/chlorine salt mineral beds are identified, the factories could be shipped up from earth at an acceptable cost and landed enpiece at the location of the mineral bed. The atmosphere could be substantially thickened within a few decades, at an affordable price.

Again, there are strong economic imperitives, for the simple reason that the value of the land increases dramatically if radiation levels go down and especially if hardy food crops can be grown outside of man-made structures. The cost is affordable and the results are near-term enough for the project to be taken seriously.

Shifting large asteroids and producing a breathable atmosphere are longer term options that are probably unrealistic as conscious projects by any government. They are also unneccesary, given that humans can create a comfortable environment relatively cheaply and incrementally using plastic domes.

Mars will be paraterraformed long before any serious planetary terraforming is attempted.

nickname · 2007-05-31 06:12:12

Why smash ammonia asteroids into Mars when you can put them into low Mars orbit and let the sun do the work of breaking them down.

Sure it's more work to orbit than smash, but on 100s of years to retrieve one they have time to fine tune it's approach.
No big kabooms that way.

Mars will probably never be earthlike, but a nice thick atmosphere would certainly make living on Mars much easier and radiation friendlier even under domes or underground.

Having 1 bar of pretty much any gas would make it possible to walk on the surface with just an oxygen mask and warm clothing.

We can probably make a pretty thick atmosphere without any imports on Mars given enough time.

I see your point of the floods, but even on Earth we build giant dams and flood regions.
No reason to think the same sort of thing wouldn't happen on a Mars trying to change a world.

Lots of planning time to move on Mars though

Antius · 2007-05-31 08:38:33

Maybe a 1 bar atmosphere won't be neccesary for Mars. On skylab, the crew survived perfectly well in a 1/3rd bar atmosphere, two-thirds oxygen, one third nitrogen.

The idea of decaying cometary objects in orbit is much better than slamming them into the surface. If Mars can be given a significant magnetic field, then the sun can do the hard work of breaking down the ammonia and water into breathable oxygen/nitrogen.

The most important hurdle in terraforming Mars is getting it to the point where it can support advanced plant life in open air. Once that is achieved, we can grow crops outside of domes, which massively improves the economics of habitation.

Spatula · 2007-05-31 09:41:50

Given Venus's hostile environment, relatively deep gravity well and general lack of anything exceptional that it might export, I would anticipate that this will probably be a deadzone for future human colonization.

We have an entire other thread for this. Feel free to bring this up there, since you haven't yet. I've already spent a lot of time developing my case for Venus, and there's plenty more I haven't discussed yet.

Although if you want to talk about 'costing too much', you're on the wrong forum. Terraforming any planet is going to be incredibly expensive. We can't even imagine the costs properly. Every planet is a gravity well. Terraforming Mars at all would seem completely without economic merit, compared to mining all the low-gravity bodies, ignoring the neighboring planets, and calling it a day.

New Mars Forums

Announcement

#1 2007-05-29 11:41:35

Re: Terraforming Jupiter's Moons

#2 2007-05-29 14:33:52

Re: Terraforming Jupiter's Moons

#3 2007-05-29 15:24:28

Re: Terraforming Jupiter's Moons

#4 2007-05-29 17:47:32

Re: Terraforming Jupiter's Moons

#5 2007-05-29 20:22:36

Re: Terraforming Jupiter's Moons

#6 2007-05-30 05:32:12

Re: Terraforming Jupiter's Moons

#7 2007-05-30 05:39:27

Re: Terraforming Jupiter's Moons

#8 2007-05-30 05:59:26

Re: Terraforming Jupiter's Moons

#9 2007-05-30 07:17:27

Re: Terraforming Jupiter's Moons

#10 2007-05-30 08:16:48

Re: Terraforming Jupiter's Moons

#11 2007-05-30 08:56:52

Re: Terraforming Jupiter's Moons

#12 2007-05-30 09:08:52

Re: Terraforming Jupiter's Moons

#13 2007-05-30 09:31:34

Re: Terraforming Jupiter's Moons

#14 2007-05-30 09:54:00

Re: Terraforming Jupiter's Moons

#15 2007-05-30 11:42:04

Re: Terraforming Jupiter's Moons

#16 2007-05-30 14:48:57

Re: Terraforming Jupiter's Moons

#17 2007-05-31 00:43:27

Re: Terraforming Jupiter's Moons

#18 2007-05-31 00:58:50

Re: Terraforming Jupiter's Moons

#19 2007-05-31 01:12:25

Re: Terraforming Jupiter's Moons

#20 2007-05-31 04:57:19

Re: Terraforming Jupiter's Moons

#21 2007-05-31 05:11:40

Re: Terraforming Jupiter's Moons

#22 2007-05-31 05:34:16

Re: Terraforming Jupiter's Moons

#23 2007-05-31 06:12:12

Re: Terraforming Jupiter's Moons

#24 2007-05-31 08:38:33

Re: Terraforming Jupiter's Moons

#25 2007-05-31 09:41:50

Re: Terraforming Jupiter's Moons

Board footer