Which gas giant of the solar system could humanity mine and for what resource?

Question

In a close future (in 100-200 years), humanity is in an energy/resource crisis and seeks new resources in the solar system. In my story, humanity, still in need after colonizing the moon, sends a mission to harvest a gas giant in the solar system.

For plot reasons, I need the main resource to be extracted from the gas giant itself. Trying to avoid unobtainium and looking into real resources, the more logical reason I've found (and after visiting this post) was extracting helium-3 for nuclear fusion.

But I face then three problems:

• Conditions in gas giant are harsh (pressure, storms, gravity, ...) and make extraction difficult, especially on Jupiter.
• Helium-3 seems to be obtainable as a by-product of hydrogen nuclear fusion. So I guess I have to handwave to make it not enough furnished or to make hydrogen fusion power-plant not technologically available.
• The distances and delta-v make the energy requirement not very viable to send it back to earth, whatever gas giant I'm aiming for. One idea was to harvest helium-3 and at the same time, looking for other resources nearby (like mining the moons) to make it more credible.

My questions are:

• Do you have a way to make helium-3 extraction viable? Or to find another interesting resource in a gas giant?
• Which one of the gas giant of the solar system would be most likely to be exploited?

Answer 1

While Jupiter is the closest (and has an abundance of every resource in its system of moons and energy resources which could be extracted from the magnetosphere), you are specifically looking for 3He, so Jupiter becomes a non starter.

Anyone trying to mine 3He from the atmosphere of Jupiter will be battling massive radiation fields, a very deep gravity well and huge energy costs to get to and from Jupiter proper (as opposed to the Jovian system). Boosting 3He from either a balloon in Jupiter's atmosphere or using some sort of ramscoop diving into the atmosphere will require massive amounts of energy to reach escape velocity, not to mention dealing with the violent and turbulent atmosphere of Jupiter itself.

Saturn is another target, with milder conditions, and additional resources (especially the atmosphere and hydrocarbon oceans of the moon Titan), but navigating through the ring system might be too much of a risk for atmosphere miners looking to extract 3He.

You would need to go farther afield, and mine the atmosphere of Uranus. The radiation environment is very mild, the escape velocity is quite reasonable and even the system of rings is not anywhere near as daunting for mining ships to navigate around (although there is still a finite chance of impacting ring particles on the way in and out of the atmosphere).

The downside of this is you are a vast distance away from the sun and the markets. Any payloads to Earth (or shipments of miners and equipment from Earth) would need to be boosted an additional 11 Km/s to enter a minimum energy trajectory, and would essentially take years to reach their destination. For automated cryogenic tankers of 3He this may not be an issue (so long as the "pipeline" is filled with tankers arriving on a regular basis the market is fulfilled), but not so much for people.

Another issue is the long trajectory times make for interesting market issues. A sudden spike in demand cannot be satisfied by currently arriving tankers or ones in the "pipeline", and a surge in production will result in increased supply reaching the market possibly a decade later (depending on orbital alignments and so on). We can see this in the whiskey market today, a surge in demand is boosting prices, but new "single malt" won't even be marketable for another 5-12 years depending on the distillery's aging standards. Only what is already in the warehouses is going to be available for sale for the foreseeable future. So one of your plot points might be the machinations of "futures" traders attempting to forecast the market and manipulate supply and demand to maximize profits.

So if your story revolves around plausible mid future 3He extraction, I'd tell the characters to "head to Uranus, young man!".

Answer 2

Hydrogen (deuterium) seems obvious. Since it's a light gas, it should be plentiful in the upper atmosphere, thus comparatively easy to obtain.
Deuterium( H-2) is needed as fuel for fusion reactors.

Answer 3

Everything.

Interestingly enough, I find this question strongly related to another one Powering the interplanetary trade ships of the 23rd-24th century and to different trade and space-economy questions we had recently on WB.

In my answer to the Q about trade ship, I basically have shown that even pure hydrogen is useful as the chemical reagent for extraction metals and(or) reducing oxides into the water and pure elements. In my opinion, it worth to spend 800 ton of fission fuel to be able separate elements of an 1 km diameter asteroid.

As result, it may help to build different constructions in space which may help way much better to Earth then just having some amount of ³He for energy production. Constructions in space may solve same energy problem as ³He, but they can not only satisfy our energy needs but also regulate climate on the earth and do other planetary stuff.

Hydrogen can be used as reactive mass for reactive propulsion for ships, which is important - space ecology, use an element with high abundance etc.

So, the answer to the question "interesting resource" is - Everything. Everything from a Gas giant is interesting and makes sense to haul in bulk quantities if you have a technology for that.

Composition and uses

not very scientific source for atmosphere compositions as a table.

Jupiter is the closest (except the Sun) source of molecular Hydrogen, which may be used as a reductant for many processes, and as a cheap method to bind oxygen and to store the oxygen in form of water, instead to lose it, release it, or try to keep it at cryogenic temperatures.

All gas giants are good sources of hydrogen because the closest place where one can find hydrogen free floating in form of asteroids is a distance about 900 A.U. (or probably even further, if at all hm, not sure and lazy to calculate, but there a temperature will be about 10K and hydrogen may form ice)

Hydrogen - reductant, reactive mass, cheap media to bind oxygen, cheap media to make water

D, ³He, He, Carbon, N - are just byproducts, each one has its own use, they are very useful byproducts.

Viability.

The answer how to get is a bit harder than to answer what to get.

Orbital ring like this may help to solve the problem, but they them selfs have technological problems which need to be solved.

There a lot of problems have to be solved before mining resources from Gas Giants will be viable. Winds, Gravity, delta-v - not the first problems here.

The energy source is the first one to solve - because to lifting matter from Jupiter and launching it is energy expensive. Escape velocity for Jupiter is 59.5 km/s and that is 28 times more expensive energy wise than for Earth. Thermonuclear reactor with ease will solve the problem and may be the biggest consumer in the solar system for any ³He you may mine from Jupiter.

An orbital ring or good thermonuclear engine may solve the problem with delta-v. The ring will be more energy efficient, but to be built it need significant demand for resources from Jupiter or any GG.

A bit more advanced tech - build a ring, use thermonuclear reactors and thermonuclear engines, space cables - and no problems, but as for now, we (at the moment) do not have technology which may help us to harvest gas giant resources.

Moons of gas giant are more viable and interesting options - carbon, carbon-hydrogen, N₂, NH₃. (water in asteroids -> Ceres) And those resources may be used to build rings, reactors etc when time comes.

Basically, we need a ring from the answer, space cable, fission rocket or better, fission reactor or better - and we are ready to send the Everything from a gas giant. All supply fro light elements will be from gas giant for a looong time, 50 years, until we make that active matter (almost entire answer is relevant to extraction, but first part to look for technology is Note about Venus scrap, snake elephant). Carbon nanotubes are the material of the Future, which allow us to solve all problems with extraction matter from gas giants, in this or another way, the only thing we need is to master making longer tubes and making devices from them.

Answer 4

Jupiter (the nearest gas giant) for He^3.
Helium III, the lightest isotope, is extremely rare (He^4 is much, much more common) and is theorized as being a superb fuel for nuclear fusion -- if only we could get enough. There have been fairly detailed technical proposals for mining lunar surface material for the He^3 that has collected there from the sun's solar wind; that's how valuable we think it is/will likely be. Operating in cis-Jovian space is not for the faint of human or robotic heart; high radiation and magnetic fields cause all sorts of challenging weirdness.

Answer 5

Helium Shortage

The recent concern about our helium supply, although not a significant worry for us now, points out humanity's extreme interest in having enough helium. So, helium could be an element that becomes overused and hence requires extraterrestrial mining.

To justify this, perhaps in the future, some new form of helium-hungry technology, or a significant increase in existing helium-using technology, causes Earth's supplies to be insufficient.

Answer 6

As long as you don't find Tibanna Gas, the most gas you will find on our solar gas giants will be hydrogen, with 85-95% of the atmospheres. The other gasses are somewhere between 5% and who-cares (check Wikipedia for details).

It depends on your economy if it is suitable to mine gas there or if some another solid planet is more resourceful.

Of course, if it ultimately has to be a gas giant, you need some handwave to add some gas of your choice.

Answer 7

To obtain Hydrogen-2 (deuterium) and Helium-3 for a Project Daedalus-style fusion rocket, Neptune would be the friendliest gas giant. It has a relatively shallow gravity well, relatively little orbital debris and a large ice moon with plenty of water (Triton) and it rotates slowly enough to not have lethal Van Allen belts. It is a long, long way out, but it would be far easier to handle relatively friendly cis-Neptune space than the lethal radiation pervading cis-Jupiter space.

Answer 8

Current fission reasearch seems to be based on deuterium and tritium, due to the lower Coulomb barrier (energy barrier for bringing positively charged nuclei together.) That's not to say 3He won't be useful in the distant future. However, mining it from Jupiter seems enormously difficult, because you can't build a solid base there.

Absolutely enormous quantities of gas would have to be processed in order to get any significant amount of 3He, and processing enormous quantities of gas requires equipment that is either enormous or at high pressure. Such a processing unit would be better placed on a solid body, and not so far into Jupiter's gravity well.

Jovian Shipyard

I do think the Jovian system is the right place to consider, as the other giant planets are just too far from earth. I would look at its moons, which are extraordinarily diverse, and actually enable you to appreciate the beauty (and sheer vastness) of Jupiter in the sky (something that cannot be appreciated from Jupiter itself.)

I think the Jovian moon system may be the perfect place to build very large ships in orbit (whether generation ships or Death Stars.) Each moon can contribute different raw materials.

To consider just the four Galilean moons

Io

Covered in sulphur and sulphur dioxide. Sulphur can be used in making sulphur concrete (aggregate bound together with sulphur that has melted and then been cooled) and is flammable.

Europa

Water ice surface, probable subsurface ocean, rich in salts, with an atmosphere (albeit very thin) of oxygen. This results from water being photolysed and the hydrogen escaping into space, due to the higher thermal velocity of hydrogen compared to oxygen.

Ganymede

Ice over a rock core

Callisto

Equal quantities of ice and rock, not well differentiated (the rock has not sunk to the bottom)

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The first three moons are locked in an orbital resonance with each other, which produces enormous tidal forces, which are responsible for heating up the moons, and producing volcanoes and other phenomena. There is therefore a rich source of geothermal energy on these moons, without the need for solar cells which would be very ineffective this far from the sun, (or nuclear technology, which is probably a requirement for extensive space travel, but should perhaps be conserved for when it is most needed.)

Delta v's for transfer between Jupiter's various moons are very reasonable, see the bottom right corner of http://www.projectrho.com/public_html/rocket/images/mission/deadfrog42.png

Answer 9

Alien stuff

As opposed to raw materials which might actually be present in real life (e.g. big diamonds) you could have there be alien materials on this moon. You can hand wave up what serves your plot best.

This could be ancient alien tech which we cannot replicate. The miners are scavenging an ancient alien junkyard. There could be large and small pieces, with intrinsic worth and utility - for example a tiny cold fusion motor, or a broken Z-point generator. A nearly working quantum disruptor would be a jackpot big enough for a miner to retire to balmy Vladivostok.

Or it could be alien life forms. For example, some crystalline self replicating life form, the spores of which can set a template used to restore radiation damaged cells. Or some life form capable of forming a symbiosis with Earth crop plants such that they can survive the harsh weather on Venus.

Answer 10

Uranus.

Slower escape speed among the 4 gaseous giants of the Solar System. Attractive feature: helium-3 and deuterium to produce semi-aneutron fusion The energy density of this fusion is on the order of 353 trillion joules per kg.

The deuterium-helium-3 fusion produces 24% of the X-ray energy '' 20% '' and 4% in neutrons, leaving 76% of the 353 trillion joules in charged particles that can be used directly for direct conversion to energy by eliminating the steam turbine method and opening the opportunity for a more efficient conversion medium that can conservatively reach 88%, and propulsion with that kind of melting speed. Up to 7.72% of the speed of light is possible, considering only the energy density of the 76% of charged particles, if it is possible to use 100% directly for exhaustion.

Thinking only about helium-3 contains a known average of 2 hydrogen and helium earth masses if we consider that 30% is helium so that Uranus has 60% of a helium earth mass, considering the abundance of the Primordial Nebula, which for every million of parts of helium 100 is helium-3, and while helium-3 has a mass of 75% helium-4, there are a total of 268,650,000,000,000,000 quadrillion tons of helium-3 in total Uranus or $268,65 \cdot 10^{17}$ tons of helium-3. equivalent to 206.65 billion times the helium-3 reserves in the lunar regolith if we consider that there is a total of 1.3 million tons of helium-3 in the moon's regolith.

Unlike Saturn or Jupiter, Uranus concentrates its helium in the upper layers, the interior of the planet is rich in volatiles of water ice and methane, which in turn comprise a fraction of hydrogen that, for water ice, It is on the order of 11.2%, perhaps this total ice down below will add 1.1 mass of hydrogen from the earth with the remaining oxygen and carbon-forming methane when combined with hydrogen. On Jupiter and Saturn, helium is well distributed in the layers of the two planets.

If we are discussing a potential civilization that artificially controls nuclear fusion in reactors and is capable of using it for propulsion and power generation, then we are talking about a post-scarcity civilization that would not be tied to the fate of its parent star either. one day it will come out, so gas giants or ice giants like Uranus or Neptune are true reserves of mega fuel fusion for these civilizations, even considering only deuterium + helium-3 or deuterium - deuterium catalysed by + deuterium '' creation of deuterium '' 'or the completely aneutronic fusion of helium-3 + helium-3. So the only really valuable resource here is helium-3 and deuterium, as long as your civilization already has the domain of exponential gain artificial nuclear fusion.

Yet only when all other sources of deuterium have been depleted because for each $km^3$ of water ice in other bodies of the Solar System in the rocky case there can be 34,900 tonnes of potential deuterium that can be used for catalyzed deuterium fusion and also to produce helium-3 as it fuses from the DD fusion. There are no other resources that are valuable enough in the Solar System to extract from our Gaseous Giants except deuterium and helium-3, and as for the core of these planets to be filled with valuable metals, it is much easier 16 Psyche.

Civilization could use the same pattern to extract helium-3 from brown dwarfs that have already depleted their deuterium supply but lack sufficient power to deplete helium-3, so they would choose brown dwarfs cold enough to provide access to atmospheric mining to Helium-3 + helium-3 fusion has an energy density per KG on the order of 207.5 trillion joules per KG that's well below the deuterium + helium-3 fusion but it is worth remembering that the helium-3 + helium-3 fusion is 100% aneutronic and potentially produces only half of the x-ray produced by the deuterium - helium-3 fusion.