Could We Colonize Ganymede?

Tom Kalbfus · 2014-05-05 02:42:12

Space probes have managed to operate in that radiation environment, without problems. Also the Moon is tidally locked with Jupiter, this means the high radiation will be on one hemisphere only. The radiation consists of charged particles trapped in Jupiter's magnetic field. Since Ganymede has little orbital inclination with Jupiter's magnetic field, then following the right hand rule, the charged particles will be coming up from behind Ganymede in it orbit, that means if you are in the leading hemisphere, you'll have the moon between yourself and the direction from which the radiation is coming.

Also most of the work of exploration will be done with unmanned vehicles which could be remotely controlled by human operators with telepresence if desired. As for shielding, Ganymede comes with shielding in the form of water ice, If you want it on your rovers. You can create molds with plastic, fill them with water and leave them outside for them to harden and freeze solid, you now have your ice plates that are especially fitted to attach to your rover You can have a 5-ton rover covered with 25 tons of ice shielding for a total of a 30 ton rover. On Ganymede, that ice is permanent, that ice isn't going to melt until you add heat sufficient to melt it. That 30-ton rover in Ganymede gravity weighs only 4.3 tons, which is less that it would weigh on Earth Seems to me that such a rover would be easy to test on Earth since it would weigh 5 tons on Earth, you transport the 5-ton rover to Ganymede, and then you add the especially made ice shields, and the rover with the ice still ends up weighing less than it did on Earth. Water is an easy material to work with, You simply fill a mold with the desired shape and then let it freeze. 25 tons of ice is about 25 cubic meters of ice plating.

Last edited by Tom Kalbfus (2014-05-05 02:44:24)

Quaoar · 2014-05-05 07:49:24

Tom Kalbfus wrote:

Space probes have managed to operate in that radiation environment, without problems. Also the Moon is tidally locked with Jupiter, this means the high radiation will be on one hemisphere only. The radiation consists of charged particles trapped in Jupiter's magnetic field. Since Ganymede has little orbital inclination with Jupiter's magnetic field, then following the right hand rule, the charged particles will be coming up from behind Ganymede in it orbit, that means if you are in the leading hemisphere, you'll have the moon between yourself and the direction from which the radiation is coming.

Yes it's correct. Radiation have been measured in orbit and probe has never landed on Ganymede. Theorically one emisphere has to be radiation free.
But why Ganymede and not Callisto?
Callisto is very similar to Ganymede and has amost the same resources, but is outside radiation belt.

The only reason to prefer Ganymede, may be to extract energy from radiation belt and use it to power your subglacial habitat. We can imagine two kind of devicies, magnetohydrodynamic and electrostatic (the first may be towers of coils the second a field of charged grids) that produce electric power slowing down ions. Such a colony can realy on almost unlimited energy source...

Tom Kalbfus · 2014-05-05 09:41:36

Quaoar wrote:

Tom Kalbfus wrote:
Space probes have managed to operate in that radiation environment, without problems. Also the Moon is tidally locked with Jupiter, this means the high radiation will be on one hemisphere only. The radiation consists of charged particles trapped in Jupiter's magnetic field. Since Ganymede has little orbital inclination with Jupiter's magnetic field, then following the right hand rule, the charged particles will be coming up from behind Ganymede in it orbit, that means if you are in the leading hemisphere, you'll have the moon between yourself and the direction from which the radiation is coming.
Yes it's correct. Radiation have been measured in orbit and probe has never landed on Ganymede. Theorically one emisphere has to be radiation free.
But why Ganymede and not Callisto?
Callisto is very similar to Ganymede and has amost the same resources, but is outside radiation belt.
The only reason to prefer Ganymede, may be to extract energy from radiation belt and use it to power your subglacial habitat. We can imagine two kind of devicies, magnetohydrodynamic and electrostatic (the first may be towers of coils the second a field of charged grids) that produce electric power slowing down ions. Such a colony can realy on almost unlimited energy source...

Also helium-3, Jupiter's magnetic field traps charged particles from the solar wind and some of those charged particles are helium-3 ions, and Jupiter has been doing this since the Solar System has formed. he Helium-3 should be in the icy crust, is a potential fusion fuel. To extract the helium-3 is very simple, you melt the ice.

Excelsior · 2014-05-05 10:52:26

Quaoar wrote:

But why Ganymede and not Callisto?

I would not interpret a thread about Ganymede to imply that there is anything wrong with or any reason to exclude Callisto in the grand scheme of things. The more real estate the merrier. But Callisto would be a separate thread.

JoshNH4H · 2014-05-05 10:58:21

How much helium 3 is there on Ganymede? I would imagine that, like most other claims of helium 3 resources, the concentration is incredibly low.

Tom Kalbfus · 2014-05-05 14:45:45

Excelsior wrote:

Quaoar wrote:
But why Ganymede and not Callisto?
I would not interpret a thread about Ganymede to imply that there is anything wrong with or any reason to exclude Callisto in the grand scheme of things. The more real estate the merrier. But Callisto would be a separate thread.

Ganymede is the largest moon in the Solar System, I think Callisto is third after Titan. Also Ganymede has more liquid water inside and more water in any form in general than any other Moon in the Solar System - that we know about!

I think we could tunnel through Ganymede's crust, and tunneling involves melting ice, then vehicles can travel through the tunnels from one settlement to the next. One might also tunnel down to the liquid water ocean beneath the crust and travel by submarine down there. Europa could also be settled, but a massive spaceship with excess shielding would be involved that docks with Europa's crust so a smaller ice bore can dig into it and access Europa's ocean. The amount of ice in the crust should be more than enough to protect humans from the intense radiation at this distance from Jupiter.

Terraformer · 2014-05-05 15:31:33

Tom, I really, really don't think water is on our list of resources that we need to worry about being scarce... an easily accessible source of metals is more important, because we can get water almost anywhere. Callisto has a thick... regolith?... that might have abundant clays, and crashed meteorites are going to be found on the surface, so the colonists are going to need to be spending time on the surface to get hold of them.

Tom Kalbfus · 2014-05-06 05:36:11

On Mars you have to look for water, on Ganymede just about anywhere you set down there will be water under your feet. You can use water for many different things. On Ganymede you can build stuff out of it, it is very easy to work with! It makes excellent radiation shielding, you can dig tunnels through it. and one thing you can use to dig tunnels with would be a nuclear rocket engine that uses water as reaction mass.

RobertDyck · 2014-05-06 07:42:24

Look up the density of sulphur hexafluoride: SF6. What is its density? Would it remain on the planet, or escape into space. With Ganymede gravity, what would be air pressure at the surface?

Also remember SF6 is a powerful greenhouse gas. How would that affect surface temperature?

Void · 2014-05-06 08:17:54

I guess I will intrude.

One factor is Jupiters gravity well. It is likely to be easier to get equipment onto Callisto than the other moons. Also easier to send materials from Callisto to other places in the solar system. Unless I have missed some clever space travel trick.

As for the submerged oceans, ice having a lesser specific gravity than liquid fresh water, about .9 ???? any verticle shaft will be unstable if filled with liquid water. I have thought that a oil with specific gravity similar to the surrounding ice could fill such a verticle shaft. It would be easier to keep liquid anyway. But where to get so much oil? An elivator with electic tracks might navigate the vertical shaft.

As for the radiation belts, I believe that a long time ago I encountered an article based on the thinking of a Russian for ejecting most of the particles from it. I think this reference is related to that:
http://www.tethers.com/papers/Hoyt_ES_RBR_Final.pdf

As for habitats, I think it would be rather easy to build underground chambers of a large size filled with water and air, or just water and whatever.

As for energy, on the surface, because the moons have very little in the way of seasons, it would be easy to put linear solar concentrators, where the effort to keep them pointed correctly will be relatively small.

Also, I would think that tethers (Space Elivators) anchored to the moons or to their gravity wells, where the magnetic field of Jupiter was passing through them would be a good source of energy. Also perhaps just a grid of cables layed on the surface.

As for IO, I have read that it would not be habitable due to the quakes? The tides? Still I would be tempted to think of flinging ice from Europa on to it to "Paraterraform" it. Lots of energy on that moon.

As for atmosphere? That would be nice, but I believe that Titan just barely holds on to Nitrogen. I would be pleased if one of the moons could do it, but I have reservations that it could happen. Jupiters moons get much more solar energy than Titan don't they? But then again Jupiters magnetic field keeps the solar wind away from Ganymede doesn't it?

Last edited by Void (2014-05-06 08:26:56)

Tom Kalbfus · 2014-05-06 09:48:23

RobertDyck wrote:

Look up the density of sulphur hexafluoride: SF6. What is its density? Would it remain on the planet, or escape into space. With Ganymede gravity, what would be air pressure at the surface?
Also remember SF6 is a powerful greenhouse gas. How would that affect surface temperature?

Can you breath sulphur hexafluoride safely? From its name I would guess not. Even if you mixed oxygen in with it, I'm not sure having sulphur hexafluoride in your lungs would be a great idea. Why have an atmosphere if you can't breath it.

Well I looked it up, maybe you can but there is this:

Exposure to an arc chemically breaks down SF
6 though most of the decomposition products tend to quickly re-form SF
6, a process termed "self-healing,"[6] Arcing or corona can produce disulfur decafluoride (S
2F
10), a highly toxic gas, with toxicity similar to phosgene.

Lightning could be fairly deadly as it will produce poison gas at least until it reforms SF6.

Tom Kalbfus · 2014-05-06 09:54:27

Ganymede's escape velocity is 2.7 km/sec, which is better than the Moon's 2.4 m/sec, while Mars has 5 km/s
http://en.wikipedia.org/wiki/Escape_velocity

I think it would be easier to carve out chambers in the ice and keep the internal temperatures below the freezing point of water, and then have smaller domes inside that maintain a higher temperature for human to live in and in which food crop could be grown. Ice is also transparent Would 70 meters of pure water ice be transparent? If concentrated solar light passes through it, would it warm the ice enough to sublimate? I think not. So long as most of the light that passes through does not get absorbed by the water ice. If we form the water ice roof into a convex lens, it can concentrate the light onto the smaller dome below The ice dome would have to be 5 times the diameter of the inner dome and concentrating sunlight onto that inner dome in order to have Earth normal sunlight within. The atmosphere would consist of oxygen and nitrogen, but very cold within the ice dome, carbon dioxide would tend to freeze out unless the air within the ice dome was heated sufficiently to keep that from happening.

Last edited by Tom Kalbfus (2014-05-06 10:00:56)

RobertDyck · 2014-05-06 13:10:53

Tom Kalbfus wrote:

Can you breath sulphur hexafluoride safely? From its name I would guess not. Even if you mixed oxygen in with it, I'm not sure having sulphur hexafluoride in your lungs would be a great idea. Why have an atmosphere if you can't breath it.

YouTube

Tom Kalbfus · 2014-05-06 15:35:15

Very interesting. As I expected a denser gas lowers the pitch of your voice. Not sure I would want to sound like that though, I prefer the Donald duck sound that comes with helium. 6 times heavier than air. I guess there must be a reason you don't see planets with sulfur-Hexafluoride atmospheres.

Quaoar · 2014-05-07 01:50:07

JoshNH4H wrote:

How much helium 3 is there on Ganymede? I would imagine that, like most other claims of helium 3 resources, the concentration is incredibly low.

Helium3 is not useful without a working fusion machine. Tokamak is too massive for space application at the moment the candidates may be Bussard's Polywell and Lerner's Dense Plasma Focus. But they are still far from breakeven.

Last edited by Quaoar (2014-05-07 01:51:03)

Quaoar · 2014-05-07 02:06:10

Tom Kalbfus wrote:

Very interesting. As I expected a denser gas lowers the pitch of your voice. Not sure I would want to sound like that though, I prefer the Donald duck sound that comes with helium. 6 times heavier than air. I guess there must be a reason you don't see planets with sulfur-Hexafluoride atmospheres.

We cannot use sulfur exafluoride as a buffer gas, because it is too much havier than oxygen and displace it from the lower zones.

Tom Kalbfus · 2014-05-07 03:01:30

Quaoar wrote:

JoshNH4H wrote:
How much helium 3 is there on Ganymede? I would imagine that, like most other claims of helium 3 resources, the concentration is incredibly low.
Helium3 is not useful without a working fusion machine. Tokamak is too massive for space application at the moment the candidates may be Bussard's Polywell and Lerner's Dense Plasma Focus. But they are still far from breakeven.

How much would a Tokamak weigh without the vacuum chamber?. Part of the expense in building a Tokamak is digging the tunnels and evacuating the chambers. Building one in space obliviates the need to do that tunneling.

One could still collect the helium-3, its purpose is of course to propel spaceships as a compact fuel, and helium-3 would take time to gather and process, and once can simply stock pile it until we do have a working fusion reactor. It wouldn't make sense to have a fusion reactor without the fuel. Also one form of fusion reactor that reacts quite well is a fusion bomb, we just have to perfect a Helium-3-deuterium fusion bomb and we can build a Dyson Starship.

http://en.wikipedia.org/wiki/Project_Or … ropulsion)

Last edited by Tom Kalbfus (2014-05-07 03:09:49)

Void · 2014-05-07 08:21:16

One possible way to create fusion power on an ice world would be to use the cleaner H3 Hydrogen bombs to repeatedly heat the waters of an underground lake. Then venting the lake heat to either vacuum skys or in the case of Titan to atmosphere.

If done correctly, the radation produced could be isolated to that lake, and perhaps a layer of clean ice above the somewhat radioactive waters, serving as a shield for the machines and humans above the submerged lake. This might be a real good one for Titan I think. Perhaps one side of the Moon having this power source, and the other side being more for civilian habitation.

If you used your super greenhouse gass as disolved in Nitrogen, and also had this heat leakage into the atmosphere, perhaps all the methane could be vaporized, and so also serve as greenhouse gass.

After all fusion reactors are just pulsed fusion. These would just be big pulses. And with that technology, yes build space propulsion also, as you have suggested.

Ganymede is interesting, but if you then have a nuclear pulse Orion type space craft, then you should be able to go to Titan instead, and with 1+ bar of surface pressure, and a plentiful energy source, then, a new home for a human civilization. Probabbly at least as good a bet as Mars, especially if it turns out that Mars cannot support a 1/3 bar atmosphere even with heating.

Last edited by Void (2014-05-07 08:22:40)

Quaoar · 2014-05-08 06:59:23

Void wrote:

One possible way to create fusion power on an ice world would be to use the cleaner H3 Hydrogen bombs to repeatedly heat the waters of an underground lake. Then venting the lake heat to either vacuum skys or in the case of Titan to atmosphere.
If done correctly, the radation produced could be isolated to that lake, and perhaps a layer of clean ice above the somewhat radioactive waters, serving as a shield for the machines and humans above the submerged lake. This might be a real good one for Titan I think. Perhaps one side of the Moon having this power source, and the other side being more for civilian habitation.
If you used your super greenhouse gass as disolved in Nitrogen, and also had this heat leakage into the atmosphere, perhaps all the methane could be vaporized, and so also serve as greenhouse gass.
After all fusion reactors are just pulsed fusion. These would just be big pulses. And with that technology, yes build space propulsion also, as you have suggested.
Ganymede is interesting, but if you then have a nuclear pulse Orion type space craft, then you should be able to go to Titan instead, and with 1+ bar of surface pressure, and a plentiful energy source, then, a new home for a human civilization. Probabbly at least as good a bet as Mars, especially if it turns out that Mars cannot support a 1/3 bar atmosphere even with heating.

We don't need fusion power in Jovian Satelllites: we can get all the power we want from radiation belts, extracting ions energy with an electrostatic or magnetohydrodinamic direct conversion generator.
It may be interesting to discuss about the best way to colonize Jupiter's Moons: surface colonies Vs. space habitats.
Europa and Ganymede may harbor indigenous life in subglacials oceans: in this case, may be wiser to not contaminate their ecosystems and build O'Neil's cilindrest in their L1 or L2.

Void · 2014-05-08 08:01:01

I respect your thinking.

But it is the argument about blind people and an elephant. I perceive one part, you another.

Part of the argument about Ganymede is should Callisto be preferred first, and similarly if a research/small colony is established on Callisto instead,
what is the potential for Titan? Let Callisto lead to Ganymede and Titan. Surely no effort would go to Ganymede without first setting foot on
Callisto.

But my interest is broader. In the search for life in the universe the true objective is religious. It is ruling powers trying to determine
a story of who should have the highest powers of rulership over humans and animals and all living things, and finally all reachable matter.
it is a religious and financial struggle. Who gets to rule?

I do not subscribe to their contest. I rather am interested in worlds which have nitrogen dominant atmospheres. Earth and Titan are those.

So, a "Habitability" zone as defined by those looking for a second genesis is defined by the existence of a second example of life "Evolved"
independently. Why? They want to uproot the religious establishment, and so gain access to the cash register. Not a science objective, but a
political one.

I rather am interested in the belt between Earth and Titan. Those are the worlds which might in an understandable fashion support a humanoid
civilization. Will humans cross between stars ever? Not known. Not if they are all dead.

Maybe if they persist in some fashion. So there is a maybe, so far, since we currently exist.

Extended human life span (1000 years or more?) and advanced propulsion and life support, and perhaps some type of alteration of the human
form, may allow a humanoid to cross between stars.

What should they seek?

If an Earth, in a habitable zone, it either has life that produces an partial oxygen atmosphere or it doesn't. If not, then perhaps too much CO2,
by now with the nature of stars getting warmer. If life then a moral issue, and also an infectious issue.

Some persons look for habitable moons, but Jupiter's are actually fairly rare around stars studied. And large moons are likely rare, and in our
solar system those in the outer solar system are ice dominated, except Io.

So, I am interested in Earth like worlds outside the outer boundary of the habitable zone. I am hoping that they would have plate tectonics, and that
an area like Iceland would be exposed. Hot springs whatever. A place to set foot. Then with methods learned on Titan, make the whole world
habitable to a "Civilization" of human descended "Humanoids". Red Dwarf "M" stars are the most common. It is possible that they might have planets
Earth size with tidal heating in some cases. This might help to make them more useful, if they also have a nitrogen dominated atmospheres, then
they are of a greater interest. The lessons learned from Earth and Titan, and also Jupiter's and Saturn's Moons could be important.

But I am deviating from Ganymede aren't I? But part of the argument is where focus should be. While it is worthwhile to think about Ganymede, my
interests are elsewhere. But I will stop at this post, as I have expressed what I wanted to.

You certainly can resume Ganymede with or without my consent. (You have my consent if it matters)

Last edited by Void (2014-05-08 10:35:49)

Tom Kalbfus · 2014-05-08 17:17:21

It would be much easier to build a spacesuit for Ganymede than for Titan, as they latter's thick atmosphere would draw away heat from the suit through convection, and the titan Suit would have to be much more heavily insulated than the one build to Ganymede. Space itself provides its own insulation.

JoshNH4H · 2014-05-08 18:08:51

I disagree with that on the grounds that it's much more difficult to design for low pressure than low temperature, and on the grounds that the radiation environment on Ganymede is to dangerous to allow outside activities in the first place

Terraformer · 2014-05-09 04:17:35

A Ganymede space suit would have to include thick plates of radiation protection. A Titan one would only need very good insulation.

GW Johnson · 2014-05-09 08:29:20

Thermal balance for a suit can be quite complicated to analyze. Sometimes simple experimentation is a better way to develop the suit. But, the physics should guide it, even if done as simple experimentation.

In vacuo, there are radiation exchanges and there is conduction (if on a surface or otherwise in physical contact with something). On an airless Jovian moon, there is the dark sky to which you radiate away your heat, and there are two sources irradiating you (the sun and Jupiter). Radiation exchange is "controlled" by color, really spectral reflectance without transparency. Most space suits are white because of this.

The conduction is a problem through shoes standing, and through the suit if seated or prone, for whatever reason. Outer planet moons are invariably very cold, so this requires thick, low-density insulation, and it does not have to be inside your pressure envelope.

When there is an atmosphere, you also have convection effects. Outer planet moons being cold, this is invariably a heat loss to the environment. The "cure" is the same as for conduction: very thick, low-density insulation. On Titan because of the cloudiness/haze/whatever-it-is, you won't see much heat sink sky, or the sun as a source, and Saturn is less of a source than Jupiter is. On Titan, it's therefore mostly conduction and convection.

The problem with the insulation, is that when you need it, you gotta have it. But when you don't, you will have trouble getting rid of waste heat, and then tend to overheat inside your suit. That leads to the need for portable "airconditioners", even in cold places. These are bulky and heavy. This is an inherent problem with all gas-balloon full pressure suits. It has always been an inherent problem with that design approach for suits.

Without evidence or experience to point at, I do believe the MCP suit might help with this problem. You sweat through your vacuum-protective underwear (a porous but tight garment or garments, best done as individual pieces for this-and-that parts of the body), cooling by evaporation, inside your loose outer clothing, which is layered and provides the insulation and the reflectance. Add layers as needed, take them off when not needed. Just like here at home. You can eliminate the "portable air conditioner" that way, and just get back to a simple oxygen backpack.

GW

Tom Kalbfus · 2014-05-09 18:57:40

Terraformer wrote:

A Ganymede space suit would have to include thick plates of radiation protection. A Titan one would only need very good insulation.

Depends on whether you walk in the radiation shadows or not. Radiation has to come a particular direction, a Ganymede day is seven times as long as an Earth day, so that means for 3.5 days you would be protected from radiation from the bulk of Ganymede.

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