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#26 2023-10-09 19:18:35

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 9,774

Re: Moons of the solar system.

Moons perhaps too cold to Terraform


Want to Explore Neptune? Use Triton’s Atmosphere to Put on the Brakes

https://www.universetoday.com/163591/wa … he-brakes/


people discuss a video game?

I 'Terraformed' Callisto in US2 by doubleing its day/night cycle from 16 days (Tidally locked) to 8 days, and gave it a weak magnetic field of 0.01 Gauss to protect it from the little radiation it gets, and by giving it an atmosphere of 1.27 Atm. Also, the Temperature rose to -8.5 c (16 f)

https://forum.kerbalspaceprogram.com/to … m-and-why/


Perhaps more of a scifi story of worldbuilding


'fandom'

The terraforming of Callisto would be very difficult with current technology.
https://terraforming.fandom.com/wiki/Callisto

Last edited by Mars_B4_Moon (2023-10-09 19:24:23)

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#27 2023-12-09 07:26:35

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 9,774

Re: Moons of the solar system.

Fly Slowly Through Enceladus' Plumes to Detect Life
https://www.universetoday.com/164681/fl … tect-life/

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#28 2023-12-20 03:56:06

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 3,581

Re: Moons of the solar system.

There are numerous small icy moons and objects in the outer solar system.  Almost too many to count.  Terraforming these objects requires digging tunnels beneath their crusts, which are predominantly water ice.  The strength of water ice is only about 6MPa close to melting point.  But this increases to 25MPa at -20°C.  That is about the same strength as regular concrete.
https://www.researchgate.net/publicatio … e_and_snow

Let us take the example of Rhea, the second largest moon of Saturn.  It has about 3% of Earth surface gravity.  We could produce habitable volume with 1bar breathable atmosphere, by melting tunnels at least 350m beneath the surface and filling them with oxygen-nitrogen atmosphere.

The weak gravity of most of these bodies would allow the tunnels to be enormously large, a km or more in diameter.  We could riddle these worlds with tunnels, until we effectively have an ice shell world, with the roof held up by columns of ice.  We would aim to keep the air in contact with the tunnel walls no warmer than about -30°C.  Inside the tunnels we would build tent structures, with fabric enclosing warmer areas.  These would be the places where people live.  To provide healthy gravity, individual buildings would rotate on bearings.  The ecosystem outside of the buildings would be in natural gravity.  It will be interesting to see how the various plants and animals adapt to that.

Waste heat will be removed by having water bodies like ponds under the tent.  These would absorb heat from the air.  Water from these bodies will be pumped through heat exchangers in water filled wells on the surface of the body.  Evaporation would dump heat into the atmosphere above the ice.  For small bodies, this could result in gradual mass loss.  For a world like Rhea, escaping water vapour would form a ring around Saturn, most of which would fall back as snow onto the moon surface.

For any of these worlds to provide a future home for humanity, mastery of controlled nuclear fusion is essential.  There is enough deuterium in the ice to power a planetary scale ecosystem for geologic timescales.  Small abounts of uranium and thorium might be available as well.  We could use fissile materials as triggers for IC fusion.  It is sustainable to use it in this way, because fission only provides a fraction of 1% of total energy release.  But it is useful for triggering the detonation wave that consumes a compressed fuel pellet.

Last edited by Calliban (2023-12-20 04:07:53)


"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."

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#29 2023-12-20 10:42:56

Void
Member
Registered: 2011-12-29
Posts: 7,395

Re: Moons of the solar system.

I enjoyed your post "C".  (Getting I.S.E. on your name)

Rhea may be somewhat undifferentiated, and possibly 25% "Rocky" materials I believe.  I will check.

You may read and consider that for yourself: https://en.wikipedia.org/wiki/Rhea_(moon)

Phoebe is a retrograde orbit moon though to be a captured Centaur.  https://en.wikipedia.org/wiki/Phoebe_(moon)
Quote:

However, images from Cassini indicate that Phoebe's craters show a considerable variation in brightness, which indicate the presence of large quantities of ice below a relatively thin blanket of dark surface deposits some 300 to 500 metres (980 to 1,640 ft) thick. In addition, quantities of carbon dioxide have been detected on the surface, a finding that has never been replicated for an asteroid. It is estimated that Phoebe is about 50% rock, as opposed to the 35% or so that typifies Saturn's inner moons. For these reasons, scientists are coming to think that Phoebe is in fact a captured centaur, one of a number of icy planetoids from the Kuiper belt that orbit the Sun between Jupiter and Neptune.[26][27] Phoebe is the first such object to be imaged as anything other than a dot.

I think that when considering a moon of Saturn, you might consider that you are dealing with a Subpart of the Saturn System.

If we can find rocky materials from one of these Moons, and also work with Titan, we really might have a lot.

Even for Phoebe being retrograde, it should be possible to air brake such materials down to the surface of Titan or even to air capture it to an orbit of Titan.  I such a case we might use some of your methods for either Phoebe or Rhea, or both and other more moons as well.

But with that I have been considering Titan itself.

I have been thinking about null flotation radiator towers for Titan.  Rocky materials and also plastics and woody organic materials might be parts of these.  For flotation we may use heat, and also lifting gasses on Titan.

We have a 1.5 bar surface pressure and 1 bar is ideal for humans, and 2/3rd bar may be good as well.  1/3 bar can be tolerated as per pure Oxygen.

A tower shaped like a cone with stilts on the bottom, may be well insulated in its lower portions but an exposed radiator in its upper portions to radiate heat.  A variation of that might be a toroid around the equator.

The atmospheric height is 600 miles?  https://en.wikipedia.org/wiki/Atmosphere_of_Titan

Well, the idea needs some work, for sure.  But I am thinking that if there is no surface life on Titan, it could be considered, and the high perches would be places where Tholen's would be harvested.  Letting a layer exist lower down perhaps.

Condensation on the towers of Methane could be helpful for cooling, but of course ice buildup could be an issue higher up.

It seems that Hydrogen in the atmosphere can be reacted with Methane to make Acetylene.  There may be energy to be had from that.

As for Hydrogen also being a lifting gas usable: https://space.stackexchange.com/questio … atmosphere

I believe that the higher you go the more there is, which is not surprising.

We don't have to do towers but we might.

I like to consider what it would be like to use Starship and Crew Dragon on Titan.

If we did have a tower then Starship could land all the way down to the surface of 1.5 bar air pressure, and then do a hop up to the tower to be refilled, and then off to orbit(s) again.

I do agree with you that all types of nuclear are desired.

However, don't write off solar at the orbits of Saturn.  Mirrors might make it possible.
https://en.wikipedia.org/wiki/Sunlight

So, possibly a little better than 1% that of Earth.

But some plants can grow with much less light, and if in orbit, the sun shines most of the time on an orbital object.

If the metals are available and a robot work force, it may not be a bad plan at all.

We might hope to do something like this for Triton, and Pluto and maybe larger dwarf planets.  May need to provide a magnetic shield in many cases to keep the atmosphere though.

Done

Last edited by Void (2023-12-20 11:29:49)


Done.

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#30 2023-12-20 11:40:33

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 29,312

Re: Moons of the solar system.

So far we want a bor'ing machine for mars and with its size and tonnage we are going to be pressed for these moons where its not possible to live without going under ground for protection and resources.

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#31 2023-12-20 15:00:28

Void
Member
Registered: 2011-12-29
Posts: 7,395

Re: Moons of the solar system.

I think I will dispute that to some degree.

Phoebe appears to be quite icy, and Rhea and Titan will also be so.  So, melting and evaporation are likely to promote digging in them.

Phobe is of great interest, it seems that the ESA did some good work about it.
https://www.esa.int/Science_Exploration … out_Phoebe

Phobe may be among the worlds where a wide distribution of materials may be accessible.  Earth is one such world.
Mars is also, that is why Dr. Zubrin promotes it.
Mercury somehow seems to have joined the club.
We think Ceres and Callisto may join as well.

It is possible that the moon Rhea, may belong as well, but that is not yet proven, as it may have totally differentiated into a rocky core and icy shell. (Or it may not have).

I have been thinking about Titan and rocky materials.  The Earth has a continual fall of rocks and cosmic dust.  I would expect that Titan has it as well.

https://www.bbc.com/news/science-environment-52465237
Quote:

"We think a total of about 40,000 tonnes (so 40,000,000 kg) of extra-terrestrial material falls to Earth each year, but the vast majority of this is in the form of tiny dust grains.

Over billions of years, this might count up on Titan, if the ice shell has been stable for very long periods of time.

If it is there, then Calliban can melt a big lake with a nuclear reactor and the materials should collect at its bottom.

Rocky materials may be sourced from the inner solar system as well.

Dr. Zubrin tends not to like this sort of thing, but if the materials came from Asteroids or small moons, I think it could be OK.
https://www.bing.com/videos/riverview/r … &FORM=VIRE
Images: https://www.bing.com/images/search?q=Co … 177&ch=510

Well Saturn's light is about 1% of that of Earth, but in orbit you may have it almost 100% of the time in many situations.

This suggests that if you want 1 unit of lighted land you will need 100 units of perfect concentrating mirror.
But if you have 12-hour days, that 100 units can light 2 units of lighted land.

So then 50 to 1.

But if 20% light is sufficient for many plants then you may change the ratio again.

It then becomes 10 to 1, I believe.

https://www.therustedgarden.com/blogs/v … es-defined

Isaac Arthur discusses this in an asteroid video, I think this one: https://isaacarthur.net/video/outward-b … ing-ceres/

Keep in mind that it appears that much of the farming in space will be chemical farming, perhaps using Acetate.
https://www.wired.com/story/plants-growing-in-darkness/
Quote:

One way to do that might be to grow crops in the dark using electricity provided by solar panels, which are many times more efficient than plants at turning sunlight into energy. In a new scientific paper published in the journal Nature Food, Jinkerson and his colleagues describe using solar panels to power a process called electrocatalysis, which creates a liquid that algae, yeast, and plants can use to grow instead of sunlight.

I believe that mushrooms also do good with it.  But garden plants don't thrive.  In time version may be created that would adapt to Acetate though.  So, eventually low lighting and Acetate may become a good way to garden indoors or in space, I would hope.

But for now bulk foods from Algae, Yeast, and Mushrooms seems likely.  And I expect that in time these could become more and more palatable to humans through modifications.

As for building "Cooper Stations" in the inner solar system, they would have their own solar power supply and you might be able to fly them to Saturn slowly using the solar wind and a magnetic sailing method.  Then they could be filled with organic materials from the moons of Saturn, and even eventually from Saturn itself, perhaps.

Done

Last edited by Void (2023-12-20 15:37:46)


Done.

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#32 2023-12-26 04:58:24

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 9,774

Re: Moons of the solar system.

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#33 2024-02-16 13:58:12

Mars_B4_Moon
Member
Registered: 2006-03-23
Posts: 9,774

Re: Moons of the solar system.

Saturn's largest moon most likely uninhabitable

https://phys.org/news/2024-02-saturn-la … table.html

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