PDA

View Full Version : Atmospheric Mining and Our Gas Giants: Best Option?



Fiery Phoenix
2015-Jun-02, 08:09 PM
Just thinking out loud here: which of our solar system's four gas giants would, in your view, be a more suitable target for mining fuel (e.g. helium-3)?

For starters, the atmospheric composition for the four planets is roughly as follows (unaccounted for percentages can be attributed to trace amounts of other gases):

Jupiter: Hydrogen ~89%.8, helium ~10.2%
Saturn: Hydrogen ~96%, helium ~ 3%
Uranus: Hydrogen ~83%, helium ~15%, methane ~2.3%
Neptune: Hydrogen ~80%, helium ~19%, methane ~1%

Furthermore, let's consider some relevant facts:

Jupiter:

Much closer to us than the other three (+)
Highly unpredictable weather (-)
Monstrous magnetic field (-)


Saturn:

Highly unpredictable weather (-)
Ring system might be problematic for navigation (-)


Uranus:

Less erratic weather than Jupiter and Saturn (+)
Slower wind speeds than Neptune (+)
Steep axial tilt (-)


Neptune:

Less erratic weather than Jupiter and Saturn (+)
Wind speeds are faster than Uranus' (-)
Huge distance might prove troublesome (-)


Given the above, Uranus seems like an easy pick to me, but then again I'm probably overlooking dozens of different factors besides what's listed.

What say you? Discuss.

NEOWatcher
2015-Jun-02, 08:51 PM
Given the above, Uranus seems like an easy pick to me, but then again I'm probably overlooking dozens of different factors besides what's listed.

Uranus is also among the lowest gravity well of all. That's going to be a bigger factor than distance if you are using robotic probes.
I don't think the axial tilt is among the leading factors.

Fiery Phoenix
2015-Jun-02, 08:55 PM
Uranus is also among the lowest gravity well of all. That's going to be a bigger factor than distance if you are using robotic probes.
I don't think the axial tilt is among the leading factors.
Good point.

I know Uranus is also known for having the coldest upper atmosphere in the outer solar system. I wonder if this would assist in 'liquifying' helium and other fuel gases in any way? I'm not too sure, but it doesn't sound far-fetched an assumption.

Noclevername
2015-Jun-02, 10:45 PM
Depends on the method used to mine. Orbital scoop mining the seems the most plausible; if so, then the temperature doesn't matter, likewise gravity and storm activity, as only the very outermost layers of the atmosphere are used. You need never get deep enough to be affected by weather.

John Mendenhall
2015-Jun-02, 10:49 PM
Helium is not a fuel gas.

And hydrogen is notoriously difficult to handle.

WayneFrancis
2015-Jun-03, 02:12 AM
Helium is not a fuel gas.

And hydrogen is notoriously difficult to handle.

It isn't a chemical fuel. It is a very good fuel to be used in fusion.

Fiery Phoenix
2015-Jun-03, 05:51 AM
Helium is not a fuel gas.

And hydrogen is notoriously difficult to handle.
What Wayne said.

Helium-3 is a perfectly appropriate gas for use in nuclear fusion and nuclear power plants. It's extremely rare on Earth but is heavily abundant in the outer solar system, making it an attractive target for future mining operations. :)

IsaacKuo
2015-Jun-04, 12:41 AM
There are no helium-3 fusion reactors, nor is there any reason to use it for nuclear power plants. The hypothetical advantage of D-He3 fusion is that most of its energy goes into charged particles, which has been a reason to suggest it might be useful for interstellar propulsion. There is no advantage for nuclear power plants.

The big disadvantage of D-He3 fusion is that we don't know how to do it in a way which could generate power. We're sort of close to figuring it out for D-T fusion, but D-He3 fusion is orders of magnitude harder to induce.

Noclevername
2015-Jun-04, 02:48 AM
Deuterium is also plentifully available from seawater and comet water. Nuclear fission reactors can make Tritium. So there's not really an incentive to go after He3 fusion anyway.

John Mendenhall
2015-Jun-04, 04:47 AM
WRT to fusion fuel gases, the Wiki article on Helium 3 is here:

http://en.wikipedia.org/wiki/Helium-3#Fusion_reactions

and is guardedly optimistic. I am impressed with the idea of a fusion reactor that is not busily turning the walls of the containment vessel into junk.

DonM435
2015-Jun-04, 05:50 AM
Decades ago, Isaac Asimov had an essay about how the liquid hydrogen available from Jupiter might become important in the new age of computers.

He ended with a speculation that we might well build all the computers on Amalthea, near the source, so that Jupiter orbit might become the computer center of our solar system.



Of course, the turnaround time for getting results back to Earth might be a big negative!

publiusr
2015-Jun-06, 06:39 PM
A nuclear PROFAC might be more acceptable near a gas giant:
http://en.wikipedia.org/wiki/Propulsive_fluid_accumulator

Now here is something to think about: using tethers to allow a PROFAC spacecraft attached to a small Jovian satellite moon to lower that moon and change its direction, using drag to fuel up and move a spacerock both...