Colonizing other planets

[RocketSquid]

Which other planets in our solar system seem most habitable? Which seem the least? How would the colonies function.

I have a basic list on some of the more likely ones here:

Venus: Land based colonies would be nearly impossible, but colonies could likely float on the Venusian atmosphere due to its high density.

Mars: Mars is an option mainly because it's fairly easy to reach. Colonies would be either underground or well shielded with sandbags or water ice.

Europa: This one is a lot further out, but it has at the very least water ice, and probably liquid oceans.

Edited February 16, 2016 by RocketSquid

[Mitchz95]

This has been discusses a lot on these boards, but I guess it's good to have a dedicated thread for it.

I don't really see the point in putting a floating colony over Venus. Unless it can somehow harvest the atmosphere for valuable materials, it'll be completely dependent on imports from other colonies. Which would seem to defeat the purpose of having a colony at all.

Mars is probably the best choice. It's close, it has a decent surface gravity, and it's something we could accomplish with current technology. We just need someone to put up the cash to do it.

Europa would be a nice option as well, but it's way too far away to do anytime soon. And of course we want to make sure we won't be displacing any native life forms.

[Bill Phil]

In truth it wouldn't matter if we had NPP ships that could get to Mars in four weeks. Then they could get to Venus in like three weeks and Europa in a few months. And this is 60s tech.

Barring that, and the fact that planets kind of suck, then I'd say Mars. Or Mercury. Both have similar surface gravity and solid surfaces.

[insert_name]

yeah, asteroid mining outposts seem like the best option

[Spaceception]

@RocketSquid

1: You should put up a poll

2: I'd choose Titan, since it has seas of rocket fuel, it's near a moon that probably has life, might have exotic life (Which is even cooler) has a nicely dense atmosphere, weak gravity will make space travel/air travel simple, and it's just an awesome moon.

Edited February 16, 2016 by Spaceception

[sevenperforce]

We could move Vesta wherever we wanted it. Makes for a promising low-gravity world.

Titan is in a neat place simply due to the high access to raw materials just off-world. Also, geothermal energy galore. Shouldn't be hard to terraform.

Of the ones you listed, Mars is good if you can make it profitable. But there's a whole thread about that.

[fairytalefox]

Let's ask ourselves: what could make people create and maintain colonies? Probably the same things that make them do other things in space, right?

I'm reading Chertok's "Rockets and People". Seems like the main reasons behind the Soviet space program were (in order of importance):

1. Military. Warhead delivery measures, surveillance, that sort of things.

2. Political. Space race, we're the first, our opponents suck.

3. Economical. Doing something useful that is either impossible or stupidly over-complicated and expensive without space.

Let's apply all these to potential planetary colonies.

1. Useless. Having people on Pluto won't help you fight err... Somalia. Let's call that country "Somalia".

2. To some extent. When Somalia does have it's people on Pluto, and you don't, who's the daddy?

3. Heavily depends.

Let's talk about (2). It doesn't actually matter how many people you have on Pluto. You have them, Somalia doesn't, it's all that matters. Even more, it doesn't matter if your people are living on Pluto right now. Been there, done things, nothing to do on this ex-planet anymore. You're already the daddy, Somalia already sucks, and it will last forever. No need to spend more money on the colony. Which means "no colony". It's what happened with the American Moon program.

So all we have is economy. If we need something up there, we will be up there. Think of GSO. Will we abandon GSO any time soon? Hell no. Not while comsats are profitable. Will we abandon the Moon? Well, done already. Apparently there's no silk spice oil colonial goods on the Moon.

Will the Moon be profitable in the near future? Maybe, as an industrial base for large-scale space construction. Low gravity (but gravity nonetheless), minerals and solar radiation in abundance, relatively cheap to reach.

Will anything else be profitable in the near future? Probably not. Too far, too inhospitable.

[DerekL1963]

6 hours ago, Mitchz95 said:

Unless it can somehow harvest the atmosphere for valuable materials, it'll be completely dependent on imports from other colonies.

In the near term (several decades), all off planet colonies are going to depend on a large degree on imports.  Additive manufacturing is the key to relieving much of that, but we're a long way from a 3D printer that can 'close the loop' buy printing copies of itself as well as being able to print the machinery needed to gather and process raw materials into feedstock for itself.

The real cork in genie's bottle however is IC's - we can't even produce 1960's grade (SSI) without a significantly complex processing chain and fabrication plant.  1970's grade (something on the order of the Intel 4004) is even more complex and demanding.   Turn-of-the-century grade? Fuhgettaboutit.

[kerbiloid]

None of them, as any you can do at another planet, you can much more easily do on the Earth.
The only purpose of a large extraterrestrial colony is a vault for a part of humanity.
But:
1) It's more easy to build such vault underground.
2) Any colonized planet decreases the probability of total humanity extiction, but increases probability of billion-scale casualties.
Just because nowadays a Horrible Asteroid (tm) has the only target to hit, while if you colonize, say, Mars, there will be two targets for choice.

[Hannu2]

There are many reasons why Mars is the most habitable and practical and I think that if there will be space colonies first ones will be on Mars.

1. Travels

Mars is second easiest to travel. It takes couple of months and we know that humans can stand so long microgravity with tolerable damages. Venus is easier but I do not see any real use or interest in very risky and impractical floating colonies middle of nothing. Outer planets need years or decades to travel, if we do not invent very revolutionary propulsion devices. There are some nuclear propulsions but there are no signs that political ban against them will be removed. Their development would also need decades of time and billions of Dollars after decision before they would get man rating for interplanetary purposes.

2. Surface conditions

Conditions on Mars are extremely hostile but all other places are even much more hostile. Soil and rocks are hard and give possibilities to make caves (or use natural caves) to protect cosmic radiation. Water ice bodies in outer solar system may be too soft (at least those with significant gravity). Temperatures need less insulation and warming. Atmosphere gives little protection against radiation and micrometeorites and there are not highly radiative areas like around gas planets. Gravity is probable enough for humans. Soil is toxic on Mars but probably places with interesting organic materials on surface are much more toxic. Low pressure prevents leaks of atmospheric gases into buildings (unlike Titan).

3. Street credibility

Humans have dreamed about traveling to Mars or Martians. Mars is probably easier to sell to taxpayers, than any other celestial body. I do not believe in any private manned Mars projects in foreseeable future.

Asteroids are certainly more interesting in economic sense. However, they do not have gravity and probably there are very advanced automation AI after couple of decades when mining becomes current (at the earliest). I think that there is no need for continuous human presence for mining or refining operations. If colonies will be based it is only for governmental propaganda reasons.

[_Augustus_]

Titan! Or Venus. Both have their challenges, but consider the advantages over Mars:

- Free rocket fuel!

- No pressurized garments required!

Furthermore, Venus has higher gravity and is easier to access, so no worries about low-gravity health problems. And on Titan, you can fly. Who doesn't want that?

Callisto also works. Mercury requires too much delta-v, Europa and Io are too radiated, Ganymede would give you cancer if you stayed too long, and everything beyond Saturn takes too long to get to.

Edited February 16, 2016 by _Augustus_

[Spaceception]

32 minutes ago, _Augustus_ said:

Titan! Or Venus. Both have their challenges, but consider the advantages over Mars:

- Free rocket fuel!

- No pressurized garments required!

Furthermore, Venus has higher gravity and is easier to access, so no worries about low-gravity health problems. And on Titan, you can fly. Who doesn't want that?

Callisto also works. Mercury requires too much delta-v, Europa and Io are too radiated, Ganymede would give you cancer if you stayed too long, and everything beyond Saturn takes too long to get to.

Ayyyy!!! We're on the same page!

[Hannu2]

1 hour ago, _Augustus_ said:

Titan! Or Venus. Both have their challenges, but consider the advantages over Mars:

- Free rocket fuel!

- No pressurized garments required!

Furthermore, Venus has higher gravity and is easier to access, so no worries about low-gravity health problems. And on Titan, you can fly. Who doesn't want that?

Callisto also works. Mercury requires too much delta-v, Europa and Io are too radiated, Ganymede would give you cancer if you stayed too long, and everything beyond Saturn takes too long to get to.

There are carbon dioxide and water in Mars. It is possible to product methane and oxygen. I do not see situation on Venus or Titan significantly better. Titan have hydrocarbons but lack oxidizers and Venus's atmosphere have nothing ready to burn.There can not be significant concentrations of fuel and oxidizer on any planet. Such atmosphere would burn until either compound would be exhausted.

There are high pressure atmosphere of toxic gases in Venus (carbon dioxide, sulfuric compounds) and Titan (large variety of organic molecules). It is much more difficult to prevent gases leak in atmosphere of habitats than to keep overpressure compared to atmosphere.

[Spaceception]

3 minutes ago, Hannu2 said:

There are carbon dioxide and water in Mars. It is possible to product methane and oxygen. I do not see situation on Venus or Titan significantly better. Titan have hydrocarbons but lack oxidizers and Venus's atmosphere have nothing ready to burn.There can not be significant concentrations of fuel and oxidizer on any planet. Such atmosphere would burn until either compound would be exhausted.

There are high pressure atmosphere of toxic gases in Venus (carbon dioxide, sulfuric compounds) and Titan (large variety of organic molecules). It is much more difficult to prevent gases leak in atmosphere of habitats than to keep overpressure compared to atmosphere.

Titan has a significant amount of water on it, and from water, you can get oxygen, drinking water, moar rocket fuel, and fuel cells.

[Hannu2]

3 minutes ago, Spaceception said:

Titan has a significant amount of water on it, and from water, you can get oxygen, drinking water, moar rocket fuel, and fuel cells.

I know but where is the advantage over Mars which have also plenty of water? Titan have harsher conditions (temperature, pressure, toxicity), lack of solar energy (nuclear energy is only option on Titan) etc. problems but I can not see any real advantages over Mars. I am sure that boring bureaucrats would even prohibit flying with muscle powered gliding suits by astronauts.

[Spaceception]

Just now, Hannu2 said:

I know but where is the advantage over Mars which have also plenty of water? Titan have harsher conditions (temperature, pressure, toxicity), lack of solar energy (nuclear energy is only option on Titan) etc. problems but I can not see any real advantages over Mars. I am sure that boring bureaucrats would even prohibit flying with muscle powered gliding suits by astronauts.

I'm not exactly sure how the pressure on Titan is a problem, we can survive it.

Once we have Fusion (Which we'll likely have by the time we're on Titan) we'll be able to power a colony easily.

Plus the Nitrogen, Ammonia, and Methane can all be used as fertilizer.

I read somewhere that the cyanide on TItan wouldn't be much of a problem as the concentration isn't high enough.

[daniel l.]

34 minutes ago, Hannu2 said:

I know but where is the advantage over Mars which have also plenty of water? Titan have harsher conditions (temperature, pressure, toxicity), lack of solar energy (nuclear energy is only option on Titan) etc. problems but I can not see any real advantages over Mars. I am sure that boring bureaucrats would even prohibit flying with muscle powered gliding suits by astronauts.

Actually titan is loaded with natural gas, we could just go there and burn it using oxygen from the ice.

[_Augustus_]

30 minutes ago, daniel l. said:

Actually titan is loaded with natural gas, we could just go there and burn it using oxygen from the ice.

Yep, no need for reactors! Current tech will do.

[tater]

I'd take all those tiny bodies off the list, even the Moon is possibly not massive enough for healthy gravity, and replace them with O'Neil colonies of some kind.

Step one would be long term habitation studies under various g-loads to ensure that even 1/3 g is enough (Mars).

As they say in real estate, location, location, location. If it turns out that Mars gravity is not suitable for long-term habitation, then it's the wrong choice, regardless of other factors it might have in its favor.

[Hannu2]

32 minutes ago, _Augustus_ said:

Yep, no need for reactors! Current tech will do.

Electrolysis of water takes about 300 kJ/mole. It gives 0.5 moles or 16 g oxygen gas. It can burn 0.25 moles (4 g) of methane which gives 0.004 kg * 55.5 MJ/kg = 220 kJ. External energy is clearly needed and only possibility in Titan is a nuclear reactor. Of course it is not technical restriction and in any case many political attitudes must change thoroughly before mankind will be able to establish any space colonies or even manned temporary visits to planets.

1 hour ago, Spaceception said:

I'm not exactly sure how the pressure on Titan is a problem, we can survive it.

Once we have Fusion (Which we'll likely have by the time we're on Titan) we'll be able to power a colony easily.

Plus the Nitrogen, Ammonia, and Methane can all be used as fertilizer.

I read somewhere that the cyanide on TItan wouldn't be much of a problem as the concentration isn't high enough.

Pressure on Titan is 1.6 atm. I thought habitat pressurized to 1 bar but of course it would be possible and practical to pressurize habitats to little over ambient pressure to ensure that leaking gas flows from inside to out. As far as I know 1.7-2.0 atm is not a problem to humans if oxygen partial pressure is suitable. However, leaks of oxygen containing air can be dangerous in hydrocarbon atmosphere. But probably they are not largest challenges in colonization of Titan.

As far as I know every proposed fusion technology need massive structures. Typically they need also some exotic metals and complex structures which can not be manufactured without advanced industrial infrastructure. Maybe we have ultralight space fusion devices in 30th century but I think that then middle class people goes to Mars cities as tourists. Nitrogen, phosphorus and potassium, the most important fertilizer elements, are relatively common all over solar system. They will not limit agriculture in space colonies.

[Hannu2]

47 minutes ago, tater said:

 If it turns out that Mars gravity is not suitable for long-term habitation, then it's the wrong choice, regardless of other factors it might have in its favor.

In such situation I think that there will not be permanent space colonies before medicine gives solutions to human restrictions.

[Nibb31]

1. Figure out a rational reason to colonize another planet.
2. Pick the best target that fits that reason.
3. ???
4. Profit!

The problem is with step 1, not step 2.

Edited February 16, 2016 by Nibb31

[PB666]

1 hour ago, Hannu2 said:

Electrolysis of water takes about 300 kJ/mole. It gives 0.5 moles or 16 g oxygen gas. It can burn 0.25 moles (4 g) of methane which gives 0.004 kg * 55.5 MJ/kg = 220 kJ. External energy is clearly needed and only possibility in Titan is a nuclear reactor. Of course it is not technical restriction and in any case many political attitudes must change thoroughly before mankind will be able to establish any space colonies or even manned temporary visits to planets.

Pressure on Titan is 1.6 atm. I thought habitat pressurized to 1 bar but of course it would be possible and practical to pressurize habitats to little over ambient pressure to ensure that leaking gas flows from inside to out. As far as I know 1.7-2.0 atm is not a problem to humans if oxygen partial pressure is suitable. However, leaks of oxygen containing air can be dangerous in hydrocarbon atmosphere. But probably they are not largest challenges in colonization of Titan.

As far as I know every proposed fusion technology need massive structures. Typically they need also some exotic metals and complex structures which can not be manufactured without advanced industrial infrastructure. Maybe we have ultralight space fusion devices in 30th century but I think that then middle class people goes to Mars cities as tourists. Nitrogen, phosphorus and potassium, the most important fertilizer elements, are relatively common all over solar system. They will not limit agriculture in space colonies.

Fusion reactors are heavy 100s of tonnes, How do you land a 100 tonne reactor on a planet even if you have an atmosphere, you are talking large amounts of kinetic energy encountered in the upper atmosphere and that 100 MW reactor needs substantial amount of radiative cooling, which just tore off into the upper atmosphere. In addition to start that reactor you already need a very powerful power supply, where are you going to get that electricity from on titan solar is no-go. Fission reactor is a better choice, even Pulonium RTGs are a good choice.

[tater]

1 hour ago, Nibb31 said:

1. Figure out a rational reason to colonize another planet.
2. Pick the best target that fits that reason.
3. ???
4. Profit!

The problem is with step 1, not step 2.

I agree, but I would argue that a "back up" of humanity on another world (or deep space colony) is a rational reason, even if we agree that it's not remotely a short-term possibility. A true colony would have to have a plausible path to self-sufficiency, which by definition makes it such a "back up" of humanity assuming it reaches that goal of standing entirely alone.

Mitigating extinction-level events requires that it be outside the Earth-moon area.

That said, I think that terrestrial-based efforts to mitigate those same events are clearly more cost-effective. We need to have the ability to divert threats (we're talking about "planet killer" impacts as the primary fear). I suppose you could make the argument that the capability to do this would be boosted by a truly space-faring society, to give some credit to the "colonial" proponents. Ie: a threat might be detected such that saving Earth might be more possible given launch windows from a colony, vs the Earth. 

Edited February 16, 2016 by tater

[fredinno]

 

19 hours ago, Bill Phil said:

In truth it wouldn't matter if we had NPP ships that could get to Mars in four weeks. Then they could get to Venus in like three weeks and Europa in a few months. And this is 60s tech.

Barring that, and the fact that planets kind of suck, then I'd say Mars. Or Mercury. Both have similar surface gravity and solid surfaces.

Good luck getting NPP ships running any time soon.

18 hours ago, Spaceception said:

@RocketSquid

1: You should put up a poll

2: I'd choose Titan, since it has seas of rocket fuel, it's near a moon that probably has life, might have exotic life (Which is even cooler) has a nicely dense atmosphere, weak gravity will make space travel/air travel simple, and it's just an awesome moon.

Titan's rocket fuel is useless until you can drill deep enough to get water for oxidiser- and by then, it'dbe better to use H2 O2, since boil-off is minimal at Saturn Orbit.

18 hours ago, sevenperforce said:

We could move Vesta wherever we wanted it. Makes for a promising low-gravity world.

Titan is in a neat place simply due to the high access to raw materials just off-world. Also, geothermal energy galore. Shouldn't be hard to terraform.

Of the ones you listed, Mars is good if you can make it profitable. But there's a whole thread about that.

Vesta is a little big tomove  

 

2 hours ago, PB666 said:

Fusion reactors are heavy 100s of tonnes, How do you land a 100 tonne reactor on a planet even if you have an atmosphere, you are talking large amounts of kinetic energy encountered in the upper atmosphere and that 100 MW reactor needs substantial amount of radiative cooling, which just tore off into the upper atmosphere. In addition to start that reactor you already need a very powerful power supply, where are you going to get that electricity from on titan solar is no-go. Fission reactor is a better choice, even Pulonium RTGs are a good choice.

So? An atmosphere can just use convection to pull heat away instead.