What planet/moon in the solar system is best one to colonize?

I’ve been watching a video on why not to colonize Mars and it struck me that SD would be a great spot to discuss solar system colonization. So let’s get to it.

Assuming we are self-sufficient with food (hydroponics), water (recycling), oxygen (scrubbing & electrolysis) and power (nuclear) what solar system body is the best to colonize and why?

Moon: very close - only 3 days away if necessary but the dust is a major issue that would need to be dealt with.

Mars: The classic colony planet but critically thinking about it there are a ton of downsides (see video above)

Venus: Whuh?! It’s the most inhospitable planet! But there is an argument that a cloud city is the best place to inhabit. From wikipedia

Europa: I know we can recycle our water but a place colonizing a place where there is water already has got to be considered.

Titan: I’ve heard this option thrown around. Despite all of the hydrocarbons there’s no way the air is worse than Los Angeles. It makes more sense as a mining colony but then how do you get all of the hydrocarbons from there to Earth in a cost-effective manner?

Other: Please explain.

The Moon, because if we can’t make it there, we can’t make it anywhere.

All of the choices are really, really horrible. The best option is spinning tin cans.

I agree. Orbiting space stations with industries centered around zero gravity.

Maybe there could be some mining or research colonies on some planets/moons/asteroids but no serious colonies to the effect of whole families living there & raising children and such.

The moon does have going for it that it’s the closest body to the Earth, so there’s that. Pretty much everything else about it sucks though. I don’t know if the dust has to be as much of a problem. It doesn’t migrate very quickly, so if you clean up an area, it will only need to be touched up every once in a while. Seems you could use electrostatics to repel dust from objects that you don’t want dusty, and to attract it to sacrificial “lightning rods”.

Not sure exactly what you do on the moon that can’t be better done in space outside a gravity well. Building magnetic accelerators to send probes to planets or even eventually to interstellar space is about the only thing I can think of that it would be good for.

Mars sucks almost as much as the moon, and it’s much further as well. Be fun for scientific exploration and may tourism, but I don’t see a driving need to fill it up with people. In my sci-fi world that I run games in, it is a planet of war. It has not use but to be fought over to demonstrate the might of various factions.

Venus is interesting, with its semi-habitable upper atmosphere, but it’s fairly problematic to try to do anything there. It could make a good prison colony, I suppose, but I can’t think that anyone would volunteer to live there.

Anywhere you go, you are going to need substantial shielding between you and the harshness of space. We have a nice atmosphere and magnetic field that protect us here, but elsewhere is going to need physical barriers.

Asteroids is where it is really at. There are some that actually are easier to get to than to the moon (the window’s short, but the delta-v is low), and most are going to be easier than Venus or Mars. You don’t even have to dig on most of them, they are just gravel piles loosely held together by the slight gravity they exert. You could probably bury your spacecraft in an asteroid simply by pushing into it a bit. Drop a spinning station inside, and you have an asteroid colony.

Obviously, terraforming and Dyson spheres are amazing and all of that but, in terms of learning to crawl before you learn how to invent the self-walking mecha power suit, we probably need to start with some smaller concepts in mind.

The first thing is to note that the key component to colonizing space is the financial viability of it.

Right now, for example, outside of some scientists, a few die-hard explorers, and some penguins there aren’t a lot of people in Antarctica. But, on the day that they discover that there is a boat-load of unobtanium under the ice and a very efficient means of extracting it, you’re suddenly going to see some real-sized towns forming down there and people figuring out the technology for heated sidewalks.

Space needs to be profitable. All other initiatives of any size are dead on arrival until that’s solved.

In theory, there is a fair amount of unobtanium in various forms available in space. But that brings us to our second point: Gravity sucks and is expensive to overcome.

If you’re mining ore, having to haul it off the surface of Mars or the Moon or anywhere else is like trying to mine something that weighs ten tons per ounce, haul it a few thousand miles, and expect that you’re somehow going to hit a reasonable price point on the market after paying for all the logistics of hauling something that weighs ten tons per ounce a few thousand miles.

The key to space expansion, if there is one, is in mining near-Earth asteroids. In theory, that allows us to create a continuously operating “factory” in outer space that’s constantly mining ore and chucking it down to Earth to be picked up. You can amortize the “fighting gravity” part of building the factory over the long-term of having gravity somewhat on your side, once you’re in production. You don’t have to fight gravity for every single shipment (though, you do have to contend with your orbital velocity - but only enough to break orbit).

And note that this is still, in all practical senses, a large and nigh-impossible task with our current technology and commitment levels if we’re talking about trying to develop something that’s profitable over any reasonable period (e.g. 20-30 years). Colonizing a planet is massively beyond that. We can’t even colonize a chunk of ocean, 20 feet deep.

But, thirdly, asteroid mining is almost certainly a necessary step towards colonization because, again, you have to contend with gravity and economics.

Engineering is most successful when you can focus on a very specific task and eliminate the amount of variety you’re contending with.

If you have to build a Colony Ship[sup]TM[/sup] that can take off from Earth and which already contains everything you need to fly across the galaxy, restaurants, theaters, dance halls, food, farms, sleeping quarters, schools, hospitals, etc. - that’s going to be a damn-heavy thing. And not just heavy, massive as well. Almost certainly, too massive to be structurally sound enough to withstand the forces necessary for launch.

Versus, if you just have a ship that simply gets humans off Earth far enough to get largely out of our gravitational pull, with no food, no accommodations, it’s just a single-purpose box - that’s a far more achievable task in terms of finding a solution that’s not too insanely expensive (rail launchers, space elevators, laser propulsion rockets, etc.) And that’s what you want because, outside of humans and maybe some seeds, you don’t want to use anything from Earth for space travel.

Aluminum is fungible. If we mined it out of an asteroid, it works just as well as aluminum which was mined from the surface of the Earth. But, to get your Earth aluminum into outer space costs way more than using aluminum which is already out there.

Minus Star Trek’s transporter technology, humans aren’t elementally fungible. We can’t vaporize the ones here and reconstruct them at the other end out of raw elements. Us and other complex life are the only things that have to be brought out of Earth’s gravity well and, from an economic standpoint, that’s the only thing worth bringing out of the gravity well.

So you need mines and factories floating around in outer space as a prerequisite to building your space “shipyard” so that you can build your Colony Ship[sup]TM[/sup].

We’re probably a hundred or more years away from getting to that point.

By the time we do, we might realize that planetary colonization is a waste of time.

Because, we have to consider point 4: Planets are horrible.

Right now, if you wanted to live on Mars, it’s sort of like deciding to live under the ocean, in a tin can, where (for reasons unspecified) you have to live upside down and walk around with magnet boots. Should we, through magic, achieve some amount of terraforming of the planet, then it will be like you’re now living at the South Pole, still upside down, walking around with magnet boots. Woo-HOO!

You have a significant difference in the level of available light, vastly different gravity, different day lengths, etc. The human body is simply not made for Mars. Being able to grow plants on it and breath the air doesn’t suddenly make it a pleasant place to live. You’re not actually going to be much more comfortable down there than you would be in outer space. It’s all uncomfortable. But it’s probably easier, in actuality, to make space comfortable than a planetary surface.

A space station is smaller, it’s all man-made and modifiable, and the technologies will have a longer development history so they’ll all be ahead of terraforming technologies. Forcing an entire planet to become like Earth is a far larger task than forcing a small metal box to become so.

And there’s no real benefit to going down to a planet, in many ways. Once you go down, you have to bring everything back up again. Why add that cost? If you’ve developed society enough for space to be a self-sustaining market, then planets are just asteroids too large to mine and too expensive to mine, because of their gravity well.

The only case where another planet becomes a genuine source of attraction is, realistically, if we genetically engineer ourselves at the same time as we terraform, so that we can get a fully satisfying experience that’s better than living in a space station.

But, by that token, if we can do that then we can genetically engineer ourselves to be perfectly adapted to living in outer space so that it’s the most comfortable place for us, period.

And all of that is assuming that we don’t all start living in Second Life or some similar virtual reality in the next 50 years - with infinite exploration and endless possibilities - and simply stop having so many babies so that we don’t have to worry about expanding our physical production capabilities.

If we can genetically engineer ourselves, all fear of nuclear war goes away because we can engineer the killer aspect of our nature out. No more need to colonize the galaxy, to ensure our continued survival.

Should we get to the point where we start trying to colonize space, though, step 1 will be to colonize “space”, not another gravity well.

The main pro of Mars, and con of Venus, is that it is probably easier to generate heat than it is to eliminate heat.

Not so fast? Not so fast!

The good thing about mining things in space is that we are currently spending thousands of dollars a pound to get it up there. Already having it there saves a bit of resources. While I see some of the stuff shipped back to earth, (platinum group metals and the like), most of it is better being up there. Satellites is a big business, and if you can save the cost of them by using resources in space, rather than launching them from earth, then that will be economically viable.

If you cannot build electronics or complex machines in space, you can still build scaffolding and trusses other structural materials. You can then put them together in space, and so your satellite doesn’t have to be built to be able to withstand the violence of a launch. It can be bigger, as it doesn’t have to fit in a fairing, and you don’t have to have complex systems that unfold solar panels or telescope, as those can be simply built in their final positions.

Once you start having any manufacturing in space, then everything becomes easier to scale up.

That’s about dust blown around by rocket exhaust.

I’ll get back with it if I can find it, but a little while back, I saw a paper talking about the “dust atmosphere” of the moon, and one of the points that it was making was that, while the dust could reach rather high altitudes, there was very little lateral movement, suggesting that if you were able to clear an area of dust, it would stay mostly dust free for a reasonable period of time.

Anyway, dust is only one of the many downsides of the moon.

I thought that was New York? :rolleyes:

I have heard that Mars ain’t the kind of place to raise your kids.

Or inside Asteroids.

At least on Titan you would not need a pressure suit. You would need oxygen and a very warm coat but it would be less of a burden than wearing an inflated gas bag.

Ocean floor seems more doable than any space adventure. And what with climate change and everything, it’s even somewhat practical !

It does seem like SpaceX or someone should be trying to build an undersea habitat, if they’re actually thinking about going to Mars.

Or gasp maybe that’s not actually in their plans despite what they advertise! :eek:

The best choice is the Moon…'s binary planetary partner. **Kobal2 **is right.

Titan −179.5°C/-291°F; coldest temp recorded on Earth −89°C/−128°F. Better be one doozy of a coat.

The answer is the Moon - by a large margin.

Specifically, the most hospitable place for humans in our solar system other than Earth is the inside of a lava tube on the moon. Inside a lava tube you are protected from temperature extremes (it’s a constant -20 or so inside one), micrometeorites, solar wind, and cosmic rays. The dust problem goes away.

And we’re not talking about living in a cave like on Earth. Lunar lava tubes are massive. The tube in the Marius Hills has an opening about 70m wide, and the tube appears to be almost a kilometer in width in places, with a ceiling perhaps half a kilometer high in parts. Seal that and pressurize it, and you could put a million people in it. It’s basically a pre-built O’Neill space colony structure inside the moon.

Of course, pressurizing such a thing is a pipe dream with today’s technology - but then, so is terraforming Mars. And pressurizing a lava tube would be orders of magnitude easier than terraforming a planet. In the meantime, we can install inflatable habs in them without needing to shield them in any way.

But then the question becomes, what do we do on the Moon? How do we make it profitable enough to warrant a permanent manned settlement there? None of the answers to that are easy, but they ARE much easier than trying to figure out how to sustain a colony on Mars. For example, the moon is close enough that tourism might be part of the answer. But the moon also has a LOT of water, and each time we look for more, we seem to find it. There are at least 500 million tonnes of water at the South Pole in permanently shadowed craters, and probably a similar amount at the north pole. But water can also be found in the regolith in the northern and southern regions, and water can also be found in volcanic beads in places like the Aristarchus Plateau.

The lunar regolith is also made up of about 45% oxygen, and contains high abundances of titanium, aluminum, magnesium, potassium, phosphorus and other elements useful for building a lunar infrastructure. If the polar craters also contain volatiles from comets and asteroids, there could be nitrogen and other necessary chemicals in large abundance.

Mining the moon has advantages as well. For one thing, there is no weather. The environment is virtually unchanging, which makes it a lot easier to build efficient mining equipment. An excavator on Earth has to worry about mud, snow, erosion, plant life, yada yada. On the moon, not so much.

For example, the Aristarchus Plateau is covered in pyroclastic deposits - glass beads from fire fountaining volcanos. There are thousands of square kilometers of the stuff. Among other chemicals, it contains about 500 ppm of water. That doesn’t sound like much, but an automated, solar powered excavator could process millions of pounds of regolith and extract a lot of water, oxygen, iron, titanium, aluminum and other chemicals contained in those beads.

Most of those stuff wouldn’t be worth exporting to Earth, but it would make building and sustaining a colony MUCH cheaper. And the water could be cracked into hydrogen and oxygen and sold as rocket fuel, delivered to lunar orbit to fuel deep-space mining vehicles or any other spacecraft.

Doing anything other than tourism profitably on the moon is no doubt decades away, but I can’t even see a path to any kind of exploitation of Mars. And in the end, that’s what matters. No bucks, no Buck Rogers.

That’s a little misleading - there’s 0% free oxygen in regolith, so getting that oxygen is going to require quite a bit of energy, and possibly other materials like hydrogen or methane.