Jupiters Realms

Void · 2018-05-06 09:59:01

I have decided to entertain myself by posting my ideas about those solar system objects that I consider to be in the "Medium" solar system proper.

Typically our solar system (Excluding the Kepler Belt, and Oort Cloud), is described as;

1) Inner solar system.

2) Outer solar system.

The asteroid belt being considered the dividing line. (More or less).

I choose my own definition.

1) Inner Solar System

2) Medium Solar System

3) Outer Solar System

4) And lets just call the Kepler Belt and Oort Cloud the "Distant Solar System".

Stop me if you can, or in the case of the moderators, if you wish to.

In my definition set;

1) The Inner Solar System is everything between the sun and the asteroid belt, but not including the asteroid belt.

2) The Medium Solar System is Jupiter, all of it's Moons, the Trojan's, the Apollo's, and the Asteroid belt itself.

3) The Outer Solar System is everything between the Realms of Jupiter and the Kepler Belt.

4) The Distant solar system is everything beyond the orbit of Neptune, which leaves Pluto overlapping from the Kepler Belt to the Outer Solar System.

......

So with that defined by me and for me, I narrow my focus to the Medium Solar System only.

What are it's resources?

Gravity wells: It has what is likely the biggest gravity well in the solar system, and many, many smaller gravity wells, down to miniscule gravity wells.

Distribution of materials: It has rocky and icy materials including very likely ices of water, CO2, and perhaps Ammonia even, if we consider that Ceres has minerals on it's surface that show traces of Ammonia. It most likely has just about any metallic or silicate material that would be needed for an industrial space economy.

It is perhaps in the real "Goldilocks Zone" of the solar system. As far as a space faring life form might be concerned.

Solar energy is relatively dim from our perspective, but there is a lot of volume in the "Space" of the Jupiter realm, in which to place solar concentrating mirrors. So, that is not a show stopper.

A resource of the Jupiter Realm that should be considered is it's magnetic field.

In some places, such as the orbits of moons Ganymede and further in, the magnetic field represents danger due to radiation.

But at Callisto, it represents moderation of the radiation threat.

https://en.wikipedia.org/wiki/Callisto_(moon)

This makes me wonder if there may be happy places in Jupiter's magnetic field near Callisto, or further out, where protection from radiation from outside the solar system happens, but a threat from the magnetic field of Jupiter is at it's minimum.

The magnetic field could also be considered a medium for navigation also. This could be done with; https://en.wikipedia.org/wiki/Electrodynamic_tether

or;

https://en.wikipedia.org/wiki/Magnetic_sail

In the case of the tethers, it is also a power source depending on how you use it. (It does not generate power, just stores and releases it).

......

So, if SpaceX(Elon Musk) and Blue Origin(Jeff Bezos) each had a thought child, and those two thought children were married, we then have the method of accessing the Medium Solar System, and the method to dwell in it.

From SpaceX, the probable existence of a Mars population, and the learning of how to access space from a relatively small object (Mars).
That experience could be translated to Callisto.

Blue Origin will also have experience with our Moon, and even more importantly with establishing and maintaining an industrial society in orbit of a planet with a magnetic field, (The Earth).

......

I don't want to get excessively wordy, but I would think that there would be several sub realms in the Medium Solar System.

1) Callisto

2) Favorable belts in the magnetic field of Jupiter where synthetic gravity machines could be hosted relatively safely.

3) The Trojan's and Apollo's.

4) The asteroid belt proper.

5) The inner moons of Jupiter where radiation is a major hazard.

So, probably Callisto is a major piece of how you build a very large industrial society in the Medium Solar System.

......

Callisto:

https://en.wikipedia.org/wiki/Callisto_(moon)

Quote:

Callisto is composed of approximately equal amounts of rock and ices, with a density of about 1.83 g/cm3, the lowest density and surface gravity of Jupiter's major moons. Compounds detected spectroscopically on the surface include water ice,[13] carbon dioxide, silicates, and organic compounds. Investigation by the Galileo spacecraft revealed that Callisto may have a small silicate core and possibly a subsurface ocean of liquid water[13] at depths greater than 100 km.[14][4]
The surface of Callisto is the oldest and most heavily cratered in the Solar System.[15] Its surface is completely covered with impact craters.[16] It does not show any signatures of subsurface processes such as plate tectonics or volcanism, with no signs that geological activity in general has ever occurred, and is thought to have evolved predominantly under the influence of impacts.[17] Prominent surface features include multi-ring structures, variously shaped impact craters, and chains of craters (catenae) and associated scarps, ridges and deposits.[17] At a small scale, the surface is varied and made up of small, sparkly frost deposits at the tips of high spots, surrounded by a low-lying, smooth blanket of dark material.[5] This is thought to result from the sublimation-driven degradation of small landforms, which is supported by the general deficit of small impact craters and the presence of numerous small knobs, considered to be their remnants.[18] The absolute ages of the landforms are not known.
Callisto is surrounded by an extremely thin atmosphere composed of carbon dioxide[7] and probably molecular oxygen,[8] as well as by a rather intense ionosphere.[19] Callisto is thought to have formed by slow accretion from the disk of the gas and dust that surrounded Jupiter after its formation.[20] Callisto's gradual accretion and the lack of tidal heating meant that not enough heat was available for rapid differentiation. The slow convection in the interior of Callisto, which commenced soon after formation, led to partial differentiation and possibly to the formation of a subsurface ocean at a depth of 100–150 km and a small, rocky core.[21]

As far as the direct habitation of Callisto is concerned, I am going to venture that mostly Callisto would be accessed by telepresence, with some human presence on the surface, and early human habitation would be in "L" locations in synthetic gravity. Unless medicine of the future can manipulate the human body to be healthy long term in shallow gravity wells.

And then from the "L" locations expansion to other Rings of radiation shelter in orbits around Jupiter itself.

For some of the Trojans, Apollo's and perhaps some asteroids and small moons, perhaps the "Shell Worlds" that others have commented on could be implemented.

Done.

Last edited by Void (2018-05-06 10:40:10)

Void · 2018-05-06 14:22:00

One thing that matters is the question of radiation sanctuaries in the magnetic field of Jupiter.

I don't know. It sounds like the location of Callisto is tolerable for radiation. I am presuming that cosmic rays are kept out.

However if there are locations in the magnetic field even better that the orbit of Callisto, that could be worth a lot.

In that case, if true, then I have to think that using ballistic capture to get materials from the Trojans, Apollos, and the Asteroid Belt proper may be very effective due to the large gravity of Jupiter.

The point being that if there is/are a sanctuarie(s), from radiation danger then this could be a thing of great value to the human race.

......

Before making such an investment though, it would be prudent to examine Callisto to find out if the Jupiter magnetic field ever reverses or disappears as does that of the Earth. The attached article describes how they know about the reversals and absences of the Earth's magnetic field:

https://phys.org/news/2012-11-cosmic-ra … earth.html

Done

Last edited by Void (2018-05-06 14:30:08)

qraal · 2018-05-06 16:41:26

Ganymede’s intrinsic magnetic field makes its Equatorial regions even more benign in radiation terms than Callisto.

People often seem confused about radiation Belts. Earth’s are filled by captures of fragments of cosmic rays that slam into the atmosphere. Jupiter’s are made deadly because it captures the Solar Wind and accelerates those captured particles to high energy.

Void · 2018-05-06 18:44:34

qraal,

That is useful.

https://en.wikipedia.org/wiki/Ganymede_(moon)
Quote:

Ganymede's magnetic field is probably created by convection within its liquid iron core.[20] The meager magnetic field is buried within Jupiter's much larger magnetic field and would show only as a local perturbation of the field lines. The satellite has a thin oxygen atmosphere that includes O, O2, and possibly O3 (ozone).[10] Atomic hydrogen is a minor atmospheric constituent. Whether the satellite has an ionosphere associated with its atmosphere is unresolved.[21]

The above suggests (Maybe), certain favors can be obtained at Ganymede.
1) Compress the atmosphere for Oxygen.
2) Possibly find a way to extract the Atomic Hydrogen. (I think I have a notion of how).
or;
3) If it is possible for Ganymede to indeed retain an atmosphere of Oxygen, could it be possible to increase it so indeed there would be an Ozone layer.

#3 would be very important, in the case where you made greenhouses, which would of course require concentrating mirrors. Ozone would reduce the troubles for such an effort by blocking the U.V. of course.

Concentrating mirrors on Ganymede may be relatively simple as I believe it says the inclination is 2.214 to the ecliptic. I am not sure exactly about that, but I hope for a method that does not require as large an effort as on Earth or Mars.

I would think that Callisto might be mined for materials, but just possibly Ganymede might become more if medicine can learn to keep people healthy in lower gravities.

And of course being me, I would always be thinking about ice covered bodies of water. In the case of Ganymede if the molecular Hydrogen and Oxygen could be extracted from the atmosphere, then something to feed microbes, and maybe mushrooms.

To replenish the atmosphere, I would suggest concentrating mirrors where the focus impinges on a catalyst that would split water into H and O.

The concentration of Ultra Violet and the whole spectrum, perhaps at temperatures of a very high value. Then just blow water vapor on it and let the results expand into the atmosphere of Callisto or Ganymede. Maybe it would work.

Done.

Last edited by Void (2018-05-06 18:51:38)

Terraformer · 2018-05-07 06:41:13

I don't think the UV levels are much of a problem, that far out. Perhaps we can make mirrors that wouldn't reflect and concentrate the UV light? Though I expect greenhouses to use artificial lighting anyway.

Void · 2018-05-07 12:42:45

I think artificial light greenhouses indeed the preference. So, you are correct. Maybe also a dry photosynthesis at a very low pressure as well.

I am also thinking that if science wants to look for intelligent aliens, they should look at a solar systems boundary between rocky and icy materials.

That is not the liquid water goldilocks zone, but the space industrial goldilocks zone. The industrial one will be further out typically I am guessing.

Last edited by Void (2018-05-07 12:45:19)

qraal01 · 2018-05-08 05:53:05

Another unrealised 'fact' about magnetospheres is they can't stop the high energy neutrons, x-rays and gamma-rays that are produced by Solar Wind particle events. Yet we survive them just fine here on Earth as we would on any planet with sufficient atmosphere. What matters is the mass-loading - on Earth, the 10 tons per square metre.

On smaller objects, the same mass-loading means a lower surface pressure. Atmospheric column mass scales with the inverse of the surface gravity. Thus the same surface pressure would mean greater radiation protection - 2.5 times more on Mars, 6 times more on the Moon, and 7 times more on Titan. Additionally, as the scale height also inversely scales to the gravity, the atmospheres on lower gee worlds are much deeper than on Earth. This means more time for, for example, muons generated by cosmic-rays, to decay. On Earth, the muons penetrate a couple of kilometres underground before they decay. On a terraformed Mars, the atmosphere would be 2.5 times deeper and the muon exposure at the surface near negligible.

Focusing solettas can provide Earth-like insolation levels, as desired. They would be 'pseudo-lenses' with angled rings of mirrors to focus the sunlight onto the target object. Their radius would scale with the distance of the target world from the Sun in AU. Thus a Titan soletta at 10 AU would be 10 times the size of Titan. But, as Titan as a lot of methane and Callisto has a lot of dry ice, Earth-like insolation levels probably aren't needed to make significant changes to the surface temperature.

qraal01 · 2018-05-08 06:17:42

A quick aside about Titan: Back in the mid 1970s there were temperature measurements, via radio scans, of Titan which indicated temperatures of up to ~200 K. Like the argument over Venus, which inspired the Mariner 2 science experiments, there were two possible locations for the observed 'warmth' - the surface and the upper atmosphere - which were 'explained' by 3 scenarios: a warm surface, warmed by a massive greenhouse effect (up to 20 bars of N2 was computed); a warm ionosphere over a cold surface at 80 K, with a low methane surface pressure (~80 mb); and something in between the two.

Just before "Voyager 1" firmed up the data, Arecibo data supported the third option - the observed surface temperature was ~100 K, thus a 2 bar N2 atmosphere, with a bit of methane, was indicated. The top of the stratosphere was measured to be ~170 K.

Void · 2018-05-08 20:42:57

graal01,

Good information.

Frankly, with the partial exception of Mars, I come down on the side of Jeff Bezos ideas of what to do in space.

Still I support SpaceX and Elon Musk and that vision as well.

Your cautions about solar generated radiation events is valuable.

Looking forward, I think that it is likely that 2 major economic sub-divisions are likely in the "Inner Solar System":
1)Earth/Moon<>Mars is the first.
2)Mercury<>Venus being the second.
And as I have previously defined (For myself) that the "Jupiter Realms" are the "Middle Solar System", I see this as #3
3) Jupiter + its moons + Trojans + Apollos + Asteroid belt proper.

I see the Saturn/Titan/Enceladus + other moons, as possibly being stunted due to a relative lack of rocky materials.
Although it is not out of the question that some will be there in the form of displaced asteroids, rocks in the ices of Titan, that fell from space, and perhaps mining of Enceladus.

......

As far as the major moons of Jupiter and Saturn being terraformed, it is an amusing compulsion.

Just possibly one could mine a giant hole on Ganymede, with enough air pressure for a relatively open air city. But that is a stretch.

More likely habitations if they occur on Ganymede, and Callisto will be underground. For Titan, I could see very large buildings filled with breathable air. Perhaps somewhat floating, that is you could float them both by internal temperature being higher, or by also having compartments filled with Hydrogen. What's the value of Big? Well it holds heat better.

I see such humungous building being rooted to the ground, but the low gravity of Titan, and flotation techniques such as mentioned above would allow them to be very tall. They would likely be very broad also. Perhaps shaped like a cone of a pyramid.

Anyway my main focus would be as in Jeff Bezos, to have synthetic gravity machines, that is hollow worlds in orbit of Jupiter, and maybe Saturn, where large populations of humans could be sustained.

What would be the ideal population of our solar system? For one thing we don't want such a civilization to appear and then die in a flash.
So, we might prefer to have a gentile growth rate. Why so many people? Well, because if you have 10 times as many people as Earth now does living well, then you have 10 times the inventors, and other productive types. 10 times the followers as well, but as long as they have satisfactory lives they may not be too much trouble.

In fact if Elon Musk does promote his company to build another layer to the human brain, then perhaps virtually all cyborgs will productive or very evil.

https://www.theverge.com/2017/3/27/1507 … ai-cyborgs

That's not likely to be my problem.

The point being, there are a lot of things in flux and that makes it harder to project a good plan.

But for habitat for humans around Jupiter, by mining the moons, and the Trojans/Apollos, and Asteroid Belt, much "Land" should be producible.

The radiation problems should be controllable by Jupiter's magnetic field, and by simple blocking with materials such as rock/water/ice.

I don't really want to go into detail on structure, but if I were designing such habitats, the preferred things for them will be redundant safety, and the conservation of volatile materials such as water, Nitrogen, ect.

As for energy at the orbits of Jupiter;
Solar.
Magnetic/Tidal (Jupiter Spin as the original source of the energy).
Maybe Fusion.
Maybe Io as a power plant run by remote robots (Not a big fan of this, but if they had a power "mix" perhaps power exported from Io could be a certain percentage of what they would use). Such a thing would not come for a very long time I think.

But the Jupiter Realms could be a very rich part of a human solar civilization.

Maybe a civilization with sufficient means to do interstellar missions. Maybe even with the human seed, or humans themselves.

Done.

Last edited by Void (2018-05-08 21:04:16)

Terraformer · 2018-05-09 04:24:27

in Karl Schroeder's novel Permanence, settlers around Jupiter used its magnetic field to power interstellar colonisation missions to brown dwarfs, using beam powered starcraft. If the power can be generated very cheaply, that would perhaps be an option.

As far as terraforming goes, I think if the Galileans could support dense atmospheres and it was feasible to provide them, it would be a good idea. That would allow vast pressurised and oxygenated spaces to be constructed on the surface.

Void · 2018-05-09 19:58:48

Something like that would likely serve well for Callisto.

Where Io, Europa, and Ganymede show resonance, Callisto does not.

Io=1 orbit of Jupiter to Europa=2 orbits of Jupiter to Ganymede=4 orbits of Jupiter.

Three of the moons could generate power from the contrast between the motion of the particular moon, and Jupiter's rotating magnetic field.

https://en.wikipedia.org/wiki/Orbital_r … _resonance

Io will be impractical due to it's violent nature, and the radiation.
Europa will be hard to do due to the radiation.
Ganymede has a magnetic field of it's own, so I suspect that it would be not practical there.

Callisto however might work. It happens also to have the best distribution of chemicals I think, to support a starter civilization.

A network of fine wiring laid across the moon Callisto might provide an energy source where travel by rocket to maintain it would not be required. That is a base source of energy, not dependent upon space travel, once the habitation is set up.

This process will move Callisto to a lower orbit over time. Perhaps it would eventually become resonant with Io, Europa, and Ganymede.
The real source of the energy would be Jupiter's spin, and the tides that the moons raise in its atmosphere will tie the spin to the orbital power of the moons.

But a stranded civilization on Callisto might also resort to solar concentrating mirrors for power, and we don't know about nuclear potentials. Obviously it Callisto will have Hydrogen, and perhaps isotopes of it.

Further, it is possible that Hydrogen from Jupiter itself will be available in the magnetic fields of Jupiter. (Not sure).

So, quite a place to hold out after the sun goes red giant and white dwarf. I am not sure social security will be solvent by then however.
Nor am I likely to be in this world.

But a point is that in looking at white dwarfs might we find a civilization where such a similar setup might exist?

.....

Anyway there is no reason for a fledgling civilization to be restricted to the surface of Callisto. They should be able to be spread out quite far, and harvesting solar energy, in our case where we are not a white dwarf.

Not a bad arrangement I would think.

......

I recall an idea from a Russian I think.

That the particles in the radiation belts of Jupiter could be expelled by some method. By that then rendering the radiation levels much lower. But it was not certain it would work, and I don't recall how it was supposed to work.

Further I cannot find a reference to it by searching. Some of the problem is references to Jupiter, and some is the current attitude towards Russia.

Anyway, the idea is that it might be possible to "Terraform" the magnetic fields of Jupiter to make them less dangerous, by expelling the particles in them. Maybe.

......
......

Now, to get really silly:

A star system with an intelligent species, might not want to allow a red giant to swallow up the equivalent of Mercury, Venus, Earth/Moon and Mars.

So perhaps they would find a way to move those planet outward over a long period of time, and perhaps they would find a way to place them in orbit of a gas giant planet or ice giant planet with a magnetic field, and so set up a method to harvest the inertia of the planets relative to the motion of the host planets magnetic field. Further by establishing resonance, eventually they might keep such planets active volcanically or re-activate them volcanically.

I am just saying that perhaps some white dwarfs may have secret civilizations.

How about some SciFi?

Done.

Last edited by Void (2018-05-09 20:50:23)

RobertDyck · 2018-05-10 02:30:53

Void wrote:

Where Io, Europa, and Ganymede show resonance, Callisto does not.
Io=1 orbit of Jupiter to Europa=2 orbits of Jupiter to Ganymede=4 orbits of Jupiter.

A lot of silly stuff, but let's get serious. Ganymede has an orbital period of 7.154553 days. Callisto 16.68902 days. The Wikipedia article you linked talks about Ganymede-Callisto resonance. Io has an orbital period of 1.769138 days. That means for every Io orbit, Callisto orbits 9.4334 times. Not perfect, but resonance still has an effect. Astronomers noticed a resonance of the orbits of Mercury, Venus, Earth, Mars. However, that wasn't perfect. They asked if there was a reason, or was it just coincidence. Many claimed we would have to find planets around other stars to answer that; then one astronomer pointed out we could use the Jovian system as a second case study. That's when they noticed Galilean moons have resonance, and it's stronger than inner planets. Mathematicians since worked out how gravity of the bodies play with each other's orbits. Since these 4 moons were so integral to that discovery, I have to take exception to your claim Callisto does not show resonance.

elderflower · 2018-05-10 03:52:18

Surface settlements on the inner moons of Jupiter will be impractical for a long time to come due to their radiation environment (disregarding other factors). Callisto is outside the worst of Jupiter's radiation belts so would be a much better bet for a starter colony.

Void · 2018-05-16 22:24:16

Callisto:
https://en.wikipedia.org/wiki/Callisto_(moon)

Axial tilt = zero

I have had my eye on this for some time.

I may have some things to learn about this.

My hope is that for Heliostats on Callisto, you could dig a trench around the Equator (Or a small section), put a reflective foil down to it's surface, and then have a solar concentration above it, a focus.

To make it more workable, only one half of the trench as a curved trench mirror. The other side as a wall strait up, that would intercept the focus. There place an energy gathering device of choice.

In other words only build 1/2 of the cross section shown here of a trench U obviously not a good drawing, but the notion is to cut the U in half with a vertical wall, and of course flatten out the U to a more practical mirror profile.

But I am not certain, that the Axial tilt of zero is the only factor determining the position of the sun in the sky concerning latitude.

I do realize that the sun will rise and set for a day lasting 16.7 Earth days, 400.8 hours. So the focus will move up and down the wall.
But perhaps elevators/cables to move the collectors up and down appropriately.

I'm working on it.

Done

Last edited by Void (2018-05-16 22:34:30)

Calliban · 2020-07-25 12:19:55

This paper suggests that much of the ice on Europa exists as oxygen clathrates due to giga-years of exposure to Jupiter charged particle radiation and subsequent burying from impact gardening.
https://www.researchgate.net/publicatio … _of_Europa

An interesting discovery to be sure. It would suggest to me that with modest amounts of heating, the clathrates would decompose yielding oxygen. Given the amount of clathrates present, this could be sufficient for a breathable atmosphere.

I wonder if Ganymede and Callisto have similar concentrations of clathrates? According to this paper, both Europa and Callisto have emission spectra for condensed O2.
https://www.researchgate.net/publicatio … d_Callisto

Looking at the phase diagram for oxygen, suggests that at Ganymede temperatures of ~90K, oxygen will exist as liquid under a modest pressure of about 1bar. The density of any oxygen present as a liquid would be 1142kg/m3. This is considerably denser than ice. Liquid oxygen would therefore have a tendency to sink deeper into the icy crust, until reaching neutral buoyancy or reaching an impermeable layer.

https://www.engineeringtoolbox.com/oxygen-d_1422.html

It is possible that reservoirs of liquid oxygen may exist beneath the icy surfaces of the Galilean satellites. This could be accessed and allowed to spill into the atmosphere by drilling.

Last edited by Calliban (2020-07-25 12:47:55)

Void · 2020-07-25 12:42:24

I like it.

Previously they said Sulfuric Acid, and Oxidants. This is better.

Last edited by Void (2020-07-25 12:46:42)

tahanson43206 · 2020-07-25 17:04:05

For Void re #14

Your observation about the axial tilt of Callisto intrigued me.

Callisto is tidally locked into orbit by Jupiter’s orbit, which means the same face (hemisphere) is always pointing toward Jupiter.

That quote is from: https://nineplanets.org/callisto/

If the moon is tidally locked, I would expect the "axial tilt" to be that of Jupiter.

Could you expand a bit on your idea?

Second ... your anticipation of how the Sun might be observed from a location on the surface of Callisto is intriguing. It is possible that modern computer software for amateur astronomers may have reached the level of sophistication that would allow someone running the software to select Callisto as a "home" location, and run the sky predictions from there.

Certainly I would expect professional/academic astronomical software to have that capability.

I would expect the Sun to appear in the "sky" over a point on Callisto exactly as it would appear from the surface of Jupiter, if Jupiter had a surface.

(th)

Void · 2020-07-25 18:58:19

(th) you nitpicker

Can't find the claim I made, perhaps you could point it out.

This one says that it is tidal locked, but creeps over time. You will need to read it.
https://nineplanets.org/callisto/

Axial tilt as proclaimed in this article: (Maybe I need further insight from someone, I might have missed something).
https://en.wikipedia.org/wiki/Callisto_(moon)
Quote:

Axial tilt
zero[4]

Last edited by Void (2020-07-25 19:04:32)

tahanson43206 · 2020-07-25 19:00:59

For Void re #18

Here is the post where I found the reference to axial tilt:
http://newmars.com/forums/viewtopic.php … 20#p146720

(th)

Void · 2020-07-25 19:11:45

I think you can find it in post #18 now.

The reason that would be nice, I think, is that you could carve a parabolic linear mirror shape into the surface of the Moon repeatedly east to west, and then line it with a thin reflective sheet to build giant solar concentrators.

But of course in that case you have to build structure to intercept the focus. I am hoping that you would modify that shape by in your imagination cutting the mirror shape in half along the long axis, and just not carving one half of it, but have the curved half as a mirror that has a focus at the top of the vertical ice wall. Yes that might mean that you have to adjust the mirror shape so that it does put the focus there. If the axis were a bit off, wobbly, you could have mechanical means to move an interceptor device horizontally to follow it.

So, then solar power for Callisto and heat. At least that is what I hope. Might work for other Moons as well.

Actually if the Moon were flat as a cue ball, then you could trench all the way around the circumference, parallel mirrors all the way up the poles. Modifications needed for higher latitudes though I guess.

Or just make a whole lot of metal solar concentrating mirrors with mobility I guess.

Ice covered lakes? Well you would need mechanical protections, and there is not that much light to go though the lakes.

So, rather, ice covered lakes where you have artificial light. Coat the bottom with regolith for thermal insulation.

Ganymede??? Europa???

Done.

Last edited by Void (2020-07-25 19:18:52)

Void · 2020-07-26 10:10:33

Caliban, this might interest you, per Ganymede:

https://icrowdnewswire.com/2020/07/24/j … 0structure.
Quote:

Normal ice has a crystalline structure, but NASA says that the particle bombardment has caused the ice at both poles of Ganymede to become amorphous. This is because the solar particles prevented the ice molecules from crystallizing by constantly destroying the structure.

They don't say what the ice is composed of, but I have to suppose that a lot of Hydrogen has be knocked out of this amorphous ice. Perhaps then "oxygen clathrates", similar to what you mentioned for Callisto in your post #15.

This suggests that perhaps by placing materials in a recipe you might use the polar areas to cook up something that you want. Hopefully you don't have to set the timer on the oven for 1000 years though.

-------

That then leads me to Ceres. Which I believe you have mentioned as a possible dislocated outer solar system object. It seems as though it would be an obvious next step from Mars, with a modified type Starship, SSTO at both ends. The aerodynamic features would be OK, but the engines are too big to directly land I think. Perhaps you just add into the engine section, some smaller landing engines for Ceres.

Adding a magnetic field to Ceres, might give some radiation protection for the surface, except for the poles. You might then take advantage of that to use the radiation to synthesize chemicals, perhaps in shadowed craters. (Shadowed craters might be a problem on Ceres).

And I have wondered elsewhere, if an magnetic field buffeted by the solar wind, might be like a punching bag, or might flap in the solar wind like a flag. In this I wonder if by rectification methods, the AC component that might be generated could be rectified off from the imposed DC magnetic field as a power supply.

Ceres has many alien properties, that make me think that it might be reasonable to try to have spinning centrifuges in caves in it. I suppose suspended on magnetic fields. I wonder if those could be tied into the world level magnetic field? Probably not.

And of course there will be solar. I would think that solar panels with anti-solar panels bonded to the reverse side. Pretty cold on Ceres.

So, not a bad little world, and a great place to access the asteroid belt and the outer solar system.

Last edited by Void (2020-07-26 10:28:57)

Mars_B4_Moon · 2021-06-04 07:29:27

NASA's Juno to get a close look at Jupiter's Moon Ganymede
https://www.spacedaily.com/reports/NASA … e_999.html

Mars_B4_Moon · 2021-08-13 13:58:24

Stunning Photo Of Jupiter's Largest Moon Marks 10 Years Of Service For Juno
https://mashable.com/science/24025/stun … e-for-juno

Mars_B4_Moon · 2021-09-15 16:17:24

the Juno mission thread
http://newmars.com/forums/viewtopic.php?id=1538
'Jupiter in a year for Europa orbiter?'
http://newmars.com/forums/viewtopic.php?id=4309

First Evidence of Water Vapor at Jupiter’s Moon Ganymede – May Hold More Water Than All of Earth’s Oceans
https://scitechdaily.com/first-evidence … hs-oceans/

Jupiter just got smacked and an amateur astronomer caught it on camera
https://www.flickr.com/photos/24115032@N06/
Brazilian observer José Luis Pereira captured a bright flash

Last edited by Mars_B4_Moon (2021-09-15 16:20:58)

Calliban · 2021-11-21 07:16:50

There has been a long standing assumption that high ambient radiation levels put the Jovian System off limits to human exploration. Yet the Juno mission employed radiation shielding which was highly effective with quite modest column density of material. A shield consisting of 1cm of titanium reduces dose rates by a factor of 800.
https://en.m.wikipedia.org/wiki/Juno_Radiation_Vault

This would seem to suggest that the pressure hull of a manned spacecraft will provide an effective shield on Ganymede and shorter visits to Europa, at which point unprotected dose rates are in the region on 500 rem per day. Longer term habitabilty of Ganymede would require either subsurface residence or terraforming to create an atmosphere with column density of at least 45kg per square metre (0.657 millibars on Ganymede). Such an atmosphere will also protect surface structures from micro-meteorites. One option for achieving this would be to heat the surface of Ganymede sufficiently that oxygen produced over aons by radiolysis, is released from clatherates within the ice. Such heating could be affected by releasing super greenhouse gases in small quantities.

To reduce radiation dose rate by a factor of 800, implies 9.65 half thicknesses of material, implying that the half thickness of titanium is about 1mm, or 4.5kg per square metre. For long-term habitation of Europa, one must reduce surface radiation dose rates from 540rem per day to 15 rem per year (Martian levels), implying that a reduction of 13,150 is needed. This is equivalent to 13.7 half-thicknesses, or a column density of 61.7kg per m2. So atmospheric column density would need to be about 30% greater on Europa to bring unprotected human surface dose rates down to tolerable levels. For Io, some 17 half-thcknesses are needed. But the lack of water makes Io an unlikely candidate for human habitation even if the surface radiation problem is sufficiently dealt with.

One piece of good news:
https://www.astronomy.com/news/2019/10/ … ce-of-life

It would appear that Jupiter's magnetic field protects its inner satellites from cosmic radiation. A dense atmosphere will not be required to protect surface dwellers from cosmic radiation. At Jupiter's distance from the sun, solar flux is of marginal value in supporting agriculture. Growing food plants in compact volumes using artificial light is a better option as it negates the need for heating of greenhouse structures. Habitation of Ganymede would appear to require the accomplishment of controlled nuclear fusion. This is the only energy source available, given the weakness of sunlight and the paucity of minerals in an ice dominated environment, which would make fissile fuels are rarety. I have discussed options in the past of using small quantities of fissile materials to trigger denotation in compressed deuterium pellets in inertial confinement fusion. There may be sufficient fissionable materials for something like this to work.

Last edited by Calliban (2021-11-21 07:56:11)

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