A base on one of Jupiter moons

[fsci123]

In my hard scifi story there is an outpost on one of jupiters moons so far i narrowed the search to Ganymede and Callisto...
Due to the fact that europa is an irradiated ball of ice, Io is a liquid hell and, The other moons are to small.
I have enough info on radiation levels recieved by people on both moons so i do not care about radiation damage on it...

Basically im just trying to ask which moon of Jupiter either Ganymede or Callisto would be a better candidate for an outpost...

 

[Warped]

There is a lot of ice under Callisto's crust which could be useful, although there are advantages to being closer to Jupiter on Ganymede like being able to take advantage of its influence for gravity assists and stuff.

 

[Rtyh-12]

Callisto, but exactly because of the radiation. It also has a lot of ice that can be useful and low gravity makes climbing various mountains there easier.

 

[Roundaboutdan]

Callisto is also less deep inside Jupiter's gravity well, making it a more useful stopoff point for jaunts out into the Solar System using all that lovely fuel you've produced from the ice. From an exobiology standpoint Callisto is more likely to contain a liquid ocean than Ganymede, making it a more enticing scientific target as well. Callisto, being further out, would however experience longer eclipses outside of direct Earth communication, but a suitable Jovian commsat network or moon-to-moon signal relay would fix this.

 

[agentgonzo]

Callisto, just because it's got a cool name and if you had any feline pets you could call them CallistoCats. It's got a catchy ring to it.

One of my friends has a cat called Callisto. She's very pretty (the cat - the friend is so-so). The other one's called Orion (his cat, not my other friend - I have many)

 

[Mister Mxyzptlk]

Roundaboutdan, how do you produce fuel from ice that far away from the sun? Nuclear power?

 

[T.Neo]

Well, out at Jupiter you have these options;

Geothermal energy- probably not practical on Callisto due to the nature of the moon.

Energy from radioactive decay (as in an RTG) - Cannot provide enough power in its weight range.

Solar energy- can be done with efficient panels but requires a large area of panels to be practical.

Electrodynamic tethers- extract energy from Jupiter's magnetosphere (how, I am not exactly sure). Large infrastructure and would require power beaming.

Nuclear power is the only practical option for a base or even a colony (too large to be supplied by panels or RTGs, too small to warrant large spaceborne structures), it can provide a large amount of power practically out of relatively little mass.

To make rocket fuel, you would first have to collect ice, melt it and seperate contaminants, and then electrolyse it... I'm not sure, but it sounds like a pretty energy intensive process to me...

 

[SiberianTiger]

Energy from radioactive decay (as in an RTG) - Cannot provide enough power in its weight range.

Why not use a real nuclear reactor then?

By the way, I think the biggest problem with icy moons is that they are, well, icy and cold. Whatever structure you build on the surface will transfer heat to this surface, and both a good thermal insulation and energy inflow is required to keep internals of the equipment and habitable volumes warm. And that is trickier than in empty space even at Jovian orbit. I also don't imagine how people can walk surfaces of icy moons, and what kind of space suit might be good for that. Also, in surroundings of various frozen gases, any venting of such substance as oxygen or Earth's air is dangerous, because it can produce an inflammable mix.

Even "simplest" icy moons like Callisto present a set of challenges for people who may once come there, which are not met by today's technology very well, I think.

 

[Wishbone]

Judging by the tempo of Martian exploration, we're talking about approx. 50 to 60 years ahead. We can make nuclear energy-based ISRU safer, lighter (not much), but without it costs of travel are going to be immense.

 

[fsci123]

Well if you have tha ability to at least 10 people to callisto or ganymede yo will obviously have the ability to provide nuclear energy and/or solar to suply ~1000persons

 

[Screamer]

What about Moon Quakes?

I also think about moon quakes. Because of Jupiter overwhelming gravity, there must be some really bad quakes on all of Jupiter moons. Especially at IO and Europa. The surface features suggest that. A base on either Callisto or Ganymede seems more viable, but I think they also share a fair deal of moon quakes. And that mean the bases should be rather quake resistant. I imagine a crack in the structures where precious gasses escape from, like Oxygen.:facepalm:And the nerves of the human inhabitants need to be of steel for sure.:lol:

 

[T.Neo]

I'm not sure if there would be literal quakes... Europa's surface is fragmented and Io gets distorted by tidal forces, but these strike me as gradual processes rather than ones that would release great amounts of energy in a short period of time. Maybe there are localised faults though, but I would suspect these would be apparent on Io and Europa more than Ganymede and Callisto (which seem, surface-wise, to be about as dead as our moon).

By the way, I think the biggest problem with icy moons is that they are, well, icy and cold. Whatever structure you build on the surface will transfer heat to this surface, and both a good thermal insulation and energy inflow is required to keep internals of the equipment and habitable volumes warm. And that is trickier than in empty space even at Jovian orbit. I also don't imagine how people can walk surfaces of icy moons, and what kind of space suit might be good for that. Also, in surroundings of various frozen gases, any venting of such substance as oxygen or Earth's air is dangerous, because it can produce an inflammable mix.

Just because a surface is cold, does not mean that you will instantly freeze if you touch it. Boots should be easy enough, already on the Moon you can get pretty bad temperature variations (but the apollo missions did land in the morning, when surface temperatures were presumably far from their maximum). Just a bit of insulation would do fine.

You can already thermally isolate a base from the surface by slightly propping it up, like I would imagine is done with many houses in areas that have cold conditions. If temperatures are not too high as to cause sublimation of the surface, you can actually use the surface to your advantage- as a heat sink, to get rid of the waste heat on the base (waste heat from these kinds of operations would have to be dumped via radiators on a conventional spacecraft). It's all about balancing things, and it shouldn't be too hard to manage it properly. Remember, usually the problem is removing heat, so heating probably won't be much of an issue (losing some heat to the surface isn't that bad, compared to say, being immersed in a thick fluid that readily convects away your heat).

Callisto isn't so far out so as to have readily collected frozen gases such as methane or ammonia, so release of a flammable gas mix is probably highly unlikely.