The case for an economy in space

[0111narwhalz]

How about this?

Fresh water is a scarce resource in certain areas (see California) that have access to seawater. Seawater can be turned into fresh water via distillation. Distillation requires heat. Now, say we placed solar satellites with output masers tuned to water-heater wavelengths (as well as power transmission) in a high Earth orbit (meaning somewher not cluttered by Kessler). The masers point at a mirror in GEO, which then relays to the still. This heat augments the still's action, allowing for cheapened water. Let's use the American Southwest as an example. Cheaper water means more agriculture, without using the Colorado River. More water in the river means more force behind hydroelectrics (cheaper power) If carried far enough, the EPA might get interested because the Colorado reaches the sea again. Thus, perhaps subsidies are in order. Perhaps all the involved companies are in cahoots, and share profits gained via underselling competitors.

Now, back to our little satellites. Perhaps radiation pressure plays a large enough part in the orbits of the collectors, and particularly the mirror. This encourages secondary industries, such as propellant production. Perhaps this brings value to ice harvesters, which would haul ice in-system on electrolysed H2-O2 or NERVAs running on pure H2. Where do they get the power to electrolyse? From existing beamed-power installations (the collector sats) tuned to transfer wavelengths. Or perhaps deployable light sails on the way out-system. An alternative is allowing ice to impact Luna, then recover it and not bother with the circ burns. Thus the haulers never have to do two burns. If sufficiently advanced, the haulers would simply use tethers to match velocities with promising roids and do half of the transfer that way.

Once this infrastructure is in place, more exotic options such as hydrocarbon skimming from Titan's atmosphere and helium from Saturn's could become viable. Helium is already a confirmed motive, and hydrocarbons are always welcome. Hydroponics/aeroponics may benifit from null-gee or centrifugal installations, thus feeding the several spacer or lunar colonies. At this point, the colonies are food, water, and air sustainable, at least from Earth surface. From here, we could begin to look at greater expansion, as long-term habitation tech has been developed. Eventually, an attempt is made at a fully sustainable colony on planetary body capable of supplying all the necessary minerals, with supplemental beams if necessary. This colony may serve as an out-system restock point, cheapening these endeavors further. At this point, the outer bodies would become inhabited as a matter of course, the ice haulers and solar lasers would proliferate, and so on.

Whew, that was a bit long-winded, wasn't it?

Solar collecters require stationkeeping. Orbital propellant production grows, as well as 'ponics. General out-system expansion follows.

[Rune]

In that eventuality, we would be better off stopping our population growth. There is no logical reason to keep on expanding to a population of 50 billion or more, and I'm not sure that expanding in space colonies does anything to improve quality of life. A far more clever way to sustain development is to reduce population levels to a couple of billion. Distributing contraceptives and educating women over several generations is much cheaper than setting up space colonies.

Even assuming that it can even be done (show me any historical precedence), I would argue that 50 billion people would produce at least 10 times more awesome things, both intellectual and material, than 5 billion, per unit of time. You, on the other hand, seem to be advocating for a future with no growth, where the human race stays stagnant for the indefinite future. Which is the complete opposite of what humans have been doing since there have been humans around to do things, I would point out. I'm going by the most good, for the most people, as well as by historical precedence.

The world's population will stabilize by the 2050s or so. It will not reach 50 billion, let alone 500 billion.

The one economic activity that can take place in space is tourism for billionaires. Maybe, if the sabre engine works, launch costs will drop for light payloads. But that's about it. Real life isn't Firefly - space is a terribly hostile environment, extremely expensive to reach and which isn't commercially viable. Even if someone could make the point of (somehow) manufacturing spaceships in space so they don't need to get out of the Earth's gravity well, that still begs the question of who's buying those ships.

And sorry, no, no NASA. Space agencies work as a way for the State to directly invest in strategic, highly valuable manufacturing which produces a lot of jobs and boosts the countries economies (as well as providing a front for military research and procurement - it's easier to tell the world that your country is developing a civilian, peaceful, rocket to put satellites in LEO than to announce an ICBM program). Take away the economy boosting effect of space programs by moving manufacturing to places where the country nationals won't be working, and that space agency has just lost a huge reason to invest that money.

Again, you are using a trend of, at most 50 years, to predict the future history of humanity. And it would seem to contradict the previous 200,000 years of historic and pre-historic humanity. But not only that, a stagnant future is something to be avoided for it's own sake, IMHO, even if it is achievable in the first place.

Be carefull about those population asumptions. There is no way to predict how much genetic engineering and vertical agriculture might extend earth's capacities. Not to mention technologies like fusion energy that might or might not be a thing in 50 years.

I doubt that technological advancement will stop anytime soon. So a definite qnd static maximum population doesn't sound too realistic to me if it's not enforced by goverments.

Back on topic. With current launch costs it's not likely to get a micro gravity production to break even or generate a profit. The logistical costs are too high for now. But if you go back a couple of centuries, that was also true for the global supply chains and trade that is common today. It's mostly a question of infrastructure.

My best guess is that the next big business after space tourism for a rather small group of people will be in providing orbital infrastructure.

Providing fuel in orbit looks like the first step here. If you can mine fuel on the moon or asteroids and bring it to LEO, odds are good that someone is going to buy it as long as you can beat the costs of launching it directly from earths. This might be possible with mostly reusable and unmaned vessels. It's a much simpler business compared to actually constructing stations or vessels in space.

Of course technology increases the population capacity of Earth. But Earth is, after all, a finite closed system, and the ecological cost of pushing it much farther is just too great IMO. Especially when a viable alternative, at least from the technical point of view, is already imaginable, and may not be more than a couple centuries away from being economically viable. I'm taking the long view here.

Regarding the whiskey idea: that is actually a funny plausible little thing. It's in the part of "really short term future" that I didn't address much in my original reply. I just think that that part is unquestionable, there ARE markets in space already that support a launch industry, and they are getting bigger all the time. I say this as a statement of fact, because the fact is that be spend more and more every year building launchers and launching stuff. Now, how do those market grow form small robotic spacecraft assembled for hundreds of millions of dollars on Earth, to a space-based economy that actually returns to Earth more that it lifts? That's the murky mid-future that is very interesting to talk about. It is even murkier, because we don't know how the markets of today will go about dropping launch prices for the markets of tomorrow. Right now a bunch of reusable ideas are getting floated about, and of course really high productions runs like those in every other established big industry (say, the car industry) are still nowhere near, so who knows what the cost to orbit per kg, or total annual launched mass numbers will look like in 50 years.

So keep discussing it! We will probably get it wrong anyway, but it is fun to take a stab at it...

Rune. Phew, I let that slip by unnoticed and now I have a lot of reading to catch up.

[Creature]

Fun fact about space whiskey: A major distillery has been studying it. I can already see what my 60th birthday present will be.

[RAINCRAFTER]

Just going to put this here...

Seriously, go watch the first minute. It tells us that there is a small sliver of hope for mining minerals and buying the rocket fuels with the money you get from the astroids and comets packed with minerals.

[juanml82]

Again, you are using a trend of, at most 50 years, to predict the future history of humanity. And it would seem to contradict the previous 200,000 years of historic and pre-historic humanity. But not only that, a stagnant future is something to be avoided for it's own sake, IMHO, even if it is achievable in the first place.

If you want humanity to expand into inhospitable, lethal, economically inviable places, there are places like that on Earth already: the bottom of the seas, Antarctica, the Sahara desert, the most frozen parts of the Artic, probably Siberia and the Gobi desert. Those places are hardly inhabited as of today and colonizing is far cheaper than colonizing space. On top, even Antarctica or the bottom of the seas are far less hostile to human life than, for instance, the surface of Mars. However, no significant human presence exists there because it doesn't make economic sense.

There is tourism in Antarctica, for instance, as well as scientific bases. That, however, did not promote the creation of towns to serve those markets. And those towns would be vastly cheaper to develop than a Mars colony.

[magnemoe]

This has been mentioned a bunch. Many rare rare-earths are actually not super rare terrestrially; they're just not in high enough demand to justify more expensive extraction methods than are currently used. Just as with platinum, an asteroid rare earth scheme would almost certainly make itself unviable by flooding the market.

This is more important for rare earths than platinum, platinum would see lots of more use if the price dropped, you would need very serious amounts of it before it became cheaper than silver as its an good material for many uses. Rare earths has limited uses and prices would drop much faster if you added lots of it.

[Nibb31]

As a secondary payload on a Dragon, I doubt that the couple of weeks in microgravity will have any noticeable effect on the maturation process of whisky, wine, cheese, or any other food products. You could probably use it as a marketing gimmick that would allow you put an overinflated price tag on a niche luxury product for stupid rich people, but it would certainly not be sustainable basis for "an economy in space".

[Rakaydos]

As a secondary payload on a Dragon, I doubt that the couple of weeks in microgravity will have any noticeable effect on the maturation process of whisky, wine, cheese, or any other food products. You could probably use it as a marketing gimmick that would allow you put an overinflated price tag on a niche luxury product for stupid rich people, but it would certainly not be sustainable basis for "an economy in space".

"Samples of whisky produced by Suntory will be stored in the Japanese laboratory facility of the International Space Station for at least a year, with some flasks staying longer."

Reading is a thing that helps. http://www.ctvnews.ca/lifestyle/japanese-company-to-age-whisky-in-space-1.2497981

[Silver_Swift]

From that link:

Researchers for the company believe that storing the beverage in an environment with only slight temperature changes and limited liquid movement could lead to a mellower flavour.

Is there any reason this would be different from just storing it in a temperature controlled basement on earth?

I'm cool with "here is a cool thing let's see how it works in 0g" style of experiments if that is what they are doing, but if not, I'd want to know how this would effect the aging process. Are the bacteria involved in the process known to be strongly influenced by gravity?

[juanml82]

Honestly, I doubt people paying five figures for whisky or other spirits do it because of the flavor. It's more like "Space Whisky! Show off your money to your friends by showing them how much you can waste away in stupid, fancy, stuff"

[Rakaydos]

From that link:

Is there any reason this would be different from just storing it in a temperature controlled basement on earth?

I'm cool with "here is a cool thing let's see how it works in 0g" style of experiments if that is what they are doing, but if not, I'd want to know how this would effect the aging process. Are the bacteria involved in the process known to be strongly influenced by gravity?

So far, it's just "how does it work in 0 g", not yet a commercial endevor. It's plausable, though.

[Rune]

If you want humanity to expand into inhospitable, lethal, economically inviable places, there are places like that on Earth already: the bottom of the seas, Antarctica, the Sahara desert, the most frozen parts of the Artic, probably Siberia and the Gobi desert. Those places are hardly inhabited as of today and colonizing is far cheaper than colonizing space. On top, even Antarctica or the bottom of the seas are far less hostile to human life than, for instance, the surface of Mars. However, no significant human presence exists there because it doesn't make economic sense.

There is tourism in Antarctica, for instance, as well as scientific bases. That, however, did not promote the creation of towns to serve those markets. And those towns would be vastly cheaper to develop than a Mars colony.

Note that at no point did I mention a Mars colony, first of all. I can already feel you classifying me there.

Also note that all the alternative places you have mentioned have complex and rich ecosystems that would be adversely impacted by human presence, even a limited one, and that alone carries a cost in biodiversity for the biosphere as a whole that is very difficult to quantify. On the other hand, a free-floating space colony, for example, poses no threat to any know species. And the increasing ecological cost of expanding anywhere but on space was my main argument for the creation, even if it has to be artificial and subsidized, of a self-sustaining space economy.

Also note a free-floating space colony would be in a more stable and safe environment than any on Earth, on account of not being subject to plate tectonics or weather systems, and being able to move out of the way of space rocks. The only "added" (it's not like the Earth isn't bombarded by radiation all the time, or can suffer detrimental effects from solar storms...) danger of space is radiation, and that is solved like it is solved here on Earth naturally by the ground and the atmosphere: tons of material between you and the source. Having average ground levels does not even take as much as you might think...

And lastly, every place you also listed is also affected by an eventual material scarcity: no matter which way you look at it, there is less accessible material in earth's crust than in the rest of the solar system, even if you only count stuff outside any major gravity wells.

And I would like to make one last point that you short of prompted: How long has there been tourism in Antarctica compared with, say, anywhere else? Centuries of difference? You are still looking at it with a narrower time frame than I am considering, this kind of cultural/political/socioeconomic shift is more in proportion to the switch from hunter-gatherers, when we went from not being able to hurt the carrying capacity of the planet if we wanted to, to farmers, that gained the power to shift whole regional climates and ecologies. Or the industrial revolution, where we gained the ability to effect those changes on a global scale and at a much quicker pace. Maybe with this time we will gain the ability to stop affecting our homeworld's ecology in a negative manner.

Rune. Here's hoping it comes faster than I think it will.

Edited August 4, 2015 by Rune

[Silver_Swift]

Honestly, I doubt people paying five figures for whisky or other spirits do it because of the flavor. It's more like "Space Whisky! Show off your money to your friends by showing them how much you can waste away in stupid, fancy, stuff"

Oh I don't doubt that, I was just wondering if there is a scientific reason the taste would even be different from regular earth whiskey.

So far, it's just "how does it work in 0 g", not yet a commercial endevor. It's plausable, though.

Cool!

[Esme]

The main economic uses I can see for doing stuff in space are manufacturing stuff in freefall that can't easily be made under acceleration, and manufaturing stuff that's just durned dangerous to make. whilst the potential for power egenration in space are enormous, I'm with those who are dubious about beaming power from orbit; safety considerations aside, I wouldn't like to see Earth become dependent on power generated from orbit, as then whomever controls the power switch has effective control of the Earth. But there's no resaon that power generated in space couldnt be used to manufacture items that are then shipped down to earth, which may in certain cases help reduce the amount or risk of pollution a tad for some industries. Tourism is another possibility, depending on how good our technology gets.

The main reason IMO to get us out there though isn't economic - it's species survival. If we can create self-sustaining colonies off Earth, then we greatly reduce the chances of humanity (and humanity's descendents) being wiped out by something.

[Nibb31]

The main reason IMO to get us out there though isn't economic - it's species survival. If we can create self-sustaining colonies off Earth, then we greatly reduce the chances of humanity (and humanity's descendents) being wiped out by something.

If we can create self-sustaining colonies off Earth, we can create them just about anywhere on Earth, including on the ocean floors or at the bottom on 10km deep shafts. They would be much easier and cheaper and provide just as good protection against pretty much anything.

[Rakaydos]

If we can create self-sustaining colonies off Earth, we can create them just about anywhere on Earth, including on the ocean floors or at the bottom on 10km deep shafts. They would be much easier and cheaper and provide just as good protection against pretty much anything.

Anywhere on earth, however, is still working with the same biosphere, and so is still vulnerable to most of the same truely world-ending threats. If you built an underwater colony, you can bet the military complex will figure out a way to point nukes at it, and a world ending disease will find a way there.

For an interplanetary colony, "space is hard" becomes a survival trait. Whether it's a nuclear missile or a lethal pathogin, it'll take months to reach mars.

[juanml82]

Anywhere on earth, however, is still working with the same biosphere, and so is still vulnerable to most of the same truely world-ending threats. If you built an underwater colony, you can bet the military complex will figure out a way to point nukes at it, and a world ending disease will find a way there.

For an interplanetary colony, "space is hard" becomes a survival trait. Whether it's a nuclear missile or a lethal pathogin, it'll take months to reach mars.

Yes, but people don't migrate for fear of war unless there is an actual war about to happen or happening. People migrate because of economic reasons, which is the reason why poluted cities (Mexico DF, Beijing) or cities in dangerous places (Los Angeles) are among the most populated places in the world

[DerekL1963]

If we can create self-sustaining colonies off Earth

We can't.

[Kaos]

We can't.

The only reason we cannot is because we do not try.

[55delta]

I'm going to step in here to split a few hairs before the argument starts. I'm going to say that creating a space colony for redundancy (in case of an unspecified disaster) is a legitimate topic to discuss here. Creating a space colony to escape an imminent or occurring disaster is a discussion already covered by other threads. Please keep this in mind in future discussion, and the matter of whether self-sustaining colonies can be created at all is also a matter better covered in other threads.

[DerekL1963]

The only reason we cannot is because we do not try.

No, the reason we cannot build a self sustaining colony (here on Earth, or elsewhere) is that we simply cannot - there's no place that has all the needed inputs (materials) and even if there were, the number of specialties and the amount of infrastructure needed is simply overwhelming. (And that presumes we can solve the known unknowns, which is by no means a given and doesn't address the unknowns we're certain to encounter.)

I know "try your best and you'll always succeed" is what they teach kids nowadays, but that's just not how the real world works.

[Kaos]

No, the reason we cannot build a self sustaining colony (here on Earth, or elsewhere) is that we simply cannot - there's no place that has all the needed inputs (materials) and even if there were, the number of specialties and the amount of infrastructure needed is simply overwhelming. (And that presumes we can solve the known unknowns, which is by no means a given and doesn't address the unknowns we're certain to encounter.)

I know "try your best and you'll always succeed" is what they teach kids nowadays, but that's just not how the real world works.

What is self sustaining in your opinion? If that has to include to generate all its power and survive trillions of years, then it is indeed not possible. But normally one would assume that the sun is available and surviving a million years is enough (otherwise you have to deal with genetic shift more than just avoiding inbreeding.

In that case I prove the possibility by example. First of all the earth in total is a self sustaining colony. At least I do not know of any necessary imports. Then within earth there are quite some self sustaining colonies, numerous small villages with no or rarely modern technology exist all over the world; most of them in Africa, South America and Australia. The modern technology they have is not necessary for survival. So on earth there are many examples of self sustaining or easily transforming into self sustaining.

Perhaps you want to include modern technology and do not count it as colony otherwise (which is understandable, as we are very used to it and would miss it strongly). Then you need of course bigger structures, but most bigger countries could do that with some problems, but could do it. Quite some industries would not work as efficient as today, because they need to be smaller (think of computers etc.) and some imported goods have to be synthesized (which needs energy, but we have wind and solar power) but not a single thing looks impossible to me. Feel free to ask for a particular thing and country with more then 10 Million people where you think this product cannot be produced in this country or it needs so much effort that the remainder of the workforce would be to small for doing anything else. This transformation would not be easy, especially food production would be more complicated in some countries, but it would be possible. This is the reason why we trade, because it benefits. But just because we profit from trade this does not mean that we would not survive without.

Then lets look into space. The low-tech alternative is clearly not working there. So we have to construct a bigger, because high-tech colony. How big does this colony have to be initially? I will argue that an import of 100t every two years (time between two low energy transfer windows) to mars will suffice to build an arbitrary large colony there. 100t is an amount we could transport there with todays technology. And with the argument before an colony of more than 10 million inhabitants will find out how to produce these 100t themselves. And I belief the real minimum to be smaller, but with more margin the argumentation is shorter and this post is already much longer then intended.

Total consumption per astronaut is about 40 kg/day. That means our 100t suffices for living rooms and two years later supplies for 3 colonists for two years. There they build up water cleaners and recyclers and dig for water. Without water the consumption is 4 kg/day. So you can support up to 30 colonists there, or bring 3 astronauts every other year and more tools for the next 18 years. With these tools and workforce you develop some means of producing food and oxygen there and build there. Now you can expand the colony faster than bringing the modules from import and reduce your consumption to 1.5 kg/day. This is enough to support 80 people. 20 build up a chemical industry, which allows to produce more stuff on-site, reducing the imports to 0.5 kg/day. With then 240 people you find ways to produce more stuff locally. Every reduction of necessary imports by a ratio increases the number of astronauts by the same ratio, hence even more complicated stuff can be assembled. But take a look around for small companies with 20 employees and see what they can produce here on earth. When the needs are fulfilled by the other people and the imports, they will be able to do the same on mars.

If I did miss nothing this totally allows for construction of self sustaining colonies on mars. It will be more complicated on moon and even more complicated in floating cities in the atmosphere of venus, but still possible.

The numbers in the argumentation are to my best knowledge (sometimes slightly increased where I do not remember exactly, so with real numbers it is even simpler, well: less hard). I have looked up quite some of them just a month or two ago, so I should be able to find references where necessary.

If I did miss something, please point it out to me, I would like to fix my argument (or agree with you if you happen to have arguments that convince me; I try to listen to arguments and not stick to my opinion).

I agree with you that "try your best and you'll always succeed" is clearly false in general. But I think with actual technology and production capacity of the earth, mars colonies are quite possible.

[juanml82]

What is self sustaining in your opinion? If that has to include to generate all its power and survive trillions of years, then it is indeed not possible. But normally one would assume that the sun is available and surviving a million years is enough (otherwise you have to deal with genetic shift more than just avoiding inbreeding.

In that case I prove the possibility by example. First of all the earth in total is a self sustaining colony. At least I do not know of any necessary imports. Then within earth there are quite some self sustaining colonies, numerous small villages with no or rarely modern technology exist all over the world; most of them in Africa, South America and Australia. The modern technology they have is not necessary for survival. So on earth there are many examples of self sustaining or easily transforming into self sustaining.

Perhaps you want to include modern technology and do not count it as colony otherwise (which is understandable, as we are very used to it and would miss it strongly). Then you need of course bigger structures, but most bigger countries could do that with some problems, but could do it. Quite some industries would not work as efficient as today, because they need to be smaller (think of computers etc.) and some imported goods have to be synthesized (which needs energy, but we have wind and solar power) but not a single thing looks impossible to me. Feel free to ask for a particular thing and country with more then 10 Million people where you think this product cannot be produced in this country or it needs so much effort that the remainder of the workforce would be to small for doing anything else. This transformation would not be easy, especially food production would be more complicated in some countries, but it would be possible. This is the reason why we trade, because it benefits. But just because we profit from trade this does not mean that we would not survive without.

Then lets look into space. The low-tech alternative is clearly not working there. So we have to construct a bigger, because high-tech colony. How big does this colony have to be initially? I will argue that an import of 100t every two years (time between two low energy transfer windows) to mars will suffice to build an arbitrary large colony there. 100t is an amount we could transport there with todays technology. And with the argument before an colony of more than 10 million inhabitants will find out how to produce these 100t themselves. And I belief the real minimum to be smaller, but with more margin the argumentation is shorter and this post is already much longer then intended.

Total consumption per astronaut is about 40 kg/day. That means our 100t suffices for living rooms and two years later supplies for 3 colonists for two years. There they build up water cleaners and recyclers and dig for water. Without water the consumption is 4 kg/day. So you can support up to 30 colonists there, or bring 3 astronauts every other year and more tools for the next 18 years. With these tools and workforce you develop some means of producing food and oxygen there and build there. Now you can expand the colony faster than bringing the modules from import and reduce your consumption to 1.5 kg/day. This is enough to support 80 people. 20 build up a chemical industry, which allows to produce more stuff on-site, reducing the imports to 0.5 kg/day. With then 240 people you find ways to produce more stuff locally. Every reduction of necessary imports by a ratio increases the number of astronauts by the same ratio, hence even more complicated stuff can be assembled. But take a look around for small companies with 20 employees and see what they can produce here on earth. When the needs are fulfilled by the other people and the imports, they will be able to do the same on mars.

If I did miss nothing this totally allows for construction of self sustaining colonies on mars. It will be more complicated on moon and even more complicated in floating cities in the atmosphere of venus, but still possible.

The numbers in the argumentation are to my best knowledge (sometimes slightly increased where I do not remember exactly, so with real numbers it is even simpler, well: less hard). I have looked up quite some of them just a month or two ago, so I should be able to find references where necessary.

If I did miss something, please point it out to me, I would like to fix my argument (or agree with you if you happen to have arguments that convince me; I try to listen to arguments and not stick to my opinion).

I agree with you that "try your best and you'll always succeed" is clearly false in general. But I think with actual technology and production capacity of the earth, mars colonies are quite possible.

Well, first, no country is self sustaining. Even more, some products require huge economies of scale, so they can't be built for a small colony - think microprocesors, lcd panels, etc.

Second, everything you describe can be done in Antarctica today. It's not being done.

Partially, because what you describe isn't the case for an economy in space. It's a project for a government subsidized scientific program. A colony in Mars will not produce anything it can export anywhere and makes no business sense. Maybe tourism to Mars could be profitable in the future, if both the Sabre and the Vasimir engines work. But even then, it doesn't mean a permanent settlement would flourish because of that small demand - again, Antarctica is an example of that.

And as for the feasibility of Mars tourism, I think we should look at the human factor. We're talking about locking a bunch of billionaires for months in a tiny spaceship in which they'll be without the comforts and lifestyle they are used to be. Would that work?

[DerekL1963]

What is self sustaining in your opinion? If that has to include to generate all its power and survive trillions of years, then it is indeed not possible. But normally one would assume that the sun is available and surviving a million years is enough (otherwise you have to deal with genetic shift more than just avoiding inbreeding.

Precisely what it says on the tin and what it's commonly assumed to mean; A colony that requires no significant inputs in order to maintain viability.

This is the reason why we trade, because it benefits. But just because we profit from trade this does not mean that we would not survive without.

Again, you've forgotten one of the benefits of trade is to obtain goods or materials that we cannot produce ourselves, or which would be extraordinarily difficult to produce economically in sufficient quantities, or which are just flat out cheaper to import. A key example would be titanium - which the US has virtually none of AFAIK.

Total consumption per astronaut is about 40 kg/day. That means our 100t suffices for living rooms and two years later supplies for 3 colonists for two years. There they build up water cleaners and recyclers and dig for water.

If I did miss nothing this totally allows for construction of self sustaining colonies on mars.

You've missed practically everything - because you've created the industry to "build up water cleaners and recyclers" out of thin air. In the real world, the tools and materials for doing so would consume a significant quantity of the 100 tons... and that's just for the "water industry".

Even back in the 15-1700's (the great age of colonization) nobody tried to build self sufficient colonies because even then you needed too much machinery (everything from looms to paint mills) and too many people to operate them and too many farmers to feed them... (And I haven't even mentioned the specialists needed to build the machinery.) We don't need quite so many people nowadays, but the equipment required is much more complex and difficult to build.

The basic problem is that it's turtles all the way down, no process is independent, they all require infrastructure and bodies to support them. (And, as juanml82 correctly points out, there's a lot of processes that don't scale down well at all.)

I agree with you that "try your best and you'll always succeed" is clearly false in general. But I think with actual technology and production capacity of the earth, mars colonies are quite possible.

Nobody is debating whether or not Mars colonies are possible, but whether or not self sustaining colonies are possible.

[SargeRho]

1: Define significant. All the food and water, and just about any purely mechanical spare parts can be produced locally on Mars, apart from "extreme" things like turbine blades, which would take a while longer before they can be produced on Mars. Bring a CnC Mill, a CnC Lathe and a Laser cutter. Surely those will fit in the 100 ton budget of the BFR/MCT?

2: Titanium isn't a rare element, it's fairly abundant in the Earth's crust. It's used to make white paint white, that's how common it is. Titanium Dioxide is very hard to break up though.

3: So you import things from Earth for a while. Nobody is talking about building a whole self-sustaining colony in one go. (Unless you're this guy) Materials to construct buildings can be acquired locally quite easily, since Martian sand/dust/regolith is mostly made of Oxygen, Aluminium, Magnesium, Calcium, and decent amounts of Iron, Nickel, Titanium and Chromium, also Chlorine, Bromine, Sulfur, and Manganese is also present.

So, many of the high tech and structural metals are present just in the soil. Not even talking about subsurface mineral deposits.

Self-sustaining in the sense that they don't require imports of food and water are very much possible, and that's also the idea of self-sustaining that most people seem to use. Self-sustaining as in, not having to trade with Earth, yeah, that'll take a while.

Edited August 6, 2015 by SargeRho