Self-replicating colony - a challenge but how difficult?

louis · 2018-07-02 15:39:45

From the Reddit/Wiki page on Mars Colonisation:

"Giving humanity a backup planet is one of Elon's often cited reasons for going to Mars, but it is hard to understate the difficulty involved in doing this. Perhaps once a large enough colony is in place, market forces will pressure it into using the materials available on Mars whenever possible. Without such a huge driving force, it is difficult to imagine complete self sufficiency ever being accomplished.

We can, however, speak generally about what it means to be self sufficient. Mars doesn't need to have all the capabilities that earth does. Rather, a colony needs all the capabilities to build another colony; to self-replicate. "

https://www.reddit.com/r/spacex/wiki/mars

I both agree and disagree. I agree that the definition of self-sufficiency is not to replicate Earth completely but to be able to self-replicate the colony without Earth intervention (and thus sustain a highly level of technical and cultural accomplishment).

But I disagree this will be an extremely difficult task and I also disagree market forces will be necessary to drive colonisation forward although they are likely to play a part).

Basically if you want the swift establishment of a self-replicating colony, you need a plan and you need to implement that plan, just as if you were asked to create a city in the middle of the Saharan desert.

You clearly need to identify all the elements that will allow you to create a self-replicating colony: energy, mining, transport, materials processing, metallurgy, plastics, agriculture, food processing, construction, textiles, hygiene and medicinal products and manufacturing. This will involve identifying millions of items that are necessary to the self-replication process. This will be in effect a simplified infrastructure compared with Earth. Instead of 50 different types of energy, there might just be 2 or 3. Instead of 1000 different textiles, there might just be 10. Instead of the full range of medicinal products, there might just be a fairly basic range.

Having established everything that is required, you can then set about your ISRU implementation plan, identifying what items need to be sourced on Mars, what needs to be manufactured and so on.

It will of course be very complex - millions of items and hundreds of thousands of mining, refining and manufacturing processes. But it is not impossibly complex. It would be a kind of combination of the Amazon and Walmart inventories, thousands of patents, and thousands of detailed plans and designs. Or think of it as a kind of world recipe book.

In the past all this would have been a Herculean task but with IT, I think with a group of say 50 experts and engineers you could put something together in a matter of months. Most of the information will already be held in digital form.

Once you have your implementation plan, you can work towards putting it into practice. For that you need a rational sequencing...you need energy up front, clearly. What comes after that can be discussed. Probably bricks, steel, cement, and a range of plastics would follow.

I don't think market forces would get you to that point as quickly as military style planning.

Last edited by louis (2018-07-02 18:31:55)

SpaceNut · 2018-07-02 19:51:59

From a purely mechanical design without human intervention means building from nothing with each sequence of steps layed out to be able to achieve the next. That said some machines will need multiple capabilities in order to get to that next step from nothing. Now a machine really does not need to be able to build one of its self but it could build a machine to give the first more abilities such that with each capability setting out for a cooperative goal to be able to build more of each.

So a machine one needs to be able to in simple function: gather, refine/process, then make something from its work.
Next machine two would need to use the refined/ process of machine one to make something more.

The question is just how many machines, which capabilities will it have and what is the finished goal of all of them with no humans involved on site.

louis · 2018-07-03 03:31:36

Indeed.

Multi-capability (e.g. 3D printers) could be crucial in allowing for fast development of a self-replicating colony. We have to bear in mind that this self-replicating colony will be small, perhaps no more than 100,000 and so whatever area of production you look at it, it is nowhere near the volumes associated with Earth, with its 7 billion population.

I agree you need to identify the end-state goal. So for all areas of activity - energy, agriculture, mining, chemicals, materials processing, manufacturing, IT, life support systems, construction, health services, retail services, communications, transport, leisure, cultural expression etc - you need to define the capability. For agriculture, that would be the ability to grow successfully x range of plants and raise x range of animals or fish (assuming you're not staying vegetarian) and then process them for human consumption. It would include things like the Mars equivalent of the Library of Congress, as a digital version. It would include procreative ability, maternity services, nurseries, schools and universities.

Education on Mars would be more digitally based but of very high quality with probably a lot of one to one or small group tuition and a lot of robot teaching as well. A university serving 100,000 people might contain no more than 3000 students. Academics might have to cover more than one specialisation. A historian might also be a sociologist. A psychologist might also be a biologist. The Mars colony would have its own academic biases - towards subject areas like rocketry, industrial organisation, production planning and so on. There would not be much call for international relations, military history, gender studies, or archaeology (unless we discover an ancient Mars civilisation) as they would have far less relevance to the people of Mars. Some subjects like English literature for instance might be of interest but simply could not be justified in terms of resource allocation, certainly as a single course. It is likely Mars students would have longer periods of modular tertiary education (maybe 5 years, rather than 3) covering much more ground.

In my view, a community of 100,000 could self-replicate successfully at a high technical level. Self-replication might even be achieved with smaller populations but would probably be more primitive. Of course we don't know whether procreation on Mars could be successful
in a low tech society. So I think a target population of 100,000 and a hi-tech self-replication capability is a sensible goal.

SpaceNut wrote:

From a purely mechanical design without human intervention means building from nothing with each sequence of steps layed out to be able to achieve the next. That said some machines will need multiple capabilities in order to get to that next step from nothing. Now a machine really does not need to be able to build one of its self but it could build a machine to give the first more abilities such that with each capability setting out for a cooperative goal to be able to build more of each.
So a machine one needs to be able to in simple function: gather, refine/process, then make something from its work.
Next machine two would need to use the refined/ process of machine one to make something more.
The question is just how many machines, which capabilities will it have and what is the finished goal of all of them with no humans involved on site.

Terraformer · 2018-07-03 04:29:03

Getting to 99% self replicating is going to be a lot easier than 100%. There are certain things essential to modern technological society which are low mass, high value items. Things like computer chips. How long will a tonne of computer components last? There are alternatives, of course - vacuum tubes, relays etc - but there's a reason we replaced them with microprocessors. Rather than building a chip fab, it might make more sense to ensure several decades worth of chips are in storage.

That said, we probably could build a civilisation on Mars with Mercury era technology. But we wouldn't have 3D printers to make things easier. It would be like the Nazi moonbase in Iron Sky. Still, it's a level that they could subsist at if we blow ourselves up and there are no more imports of Terran goods.

Of course, if Mars turns out to be easy to proteroform (thicker atmosphere, warmer, liquid water), then things become a lot easier. No need for pressurised greenhouses - heated polytunnels would do. Oxygen extracted from the atmosphere. Worse dust storms, but also more prospect for wind power. Much simpler suits for working outside. Canals for transport.

louis · 2018-07-03 04:55:36

Yes, I agree. In reality, I don't really think this self-replication effort will be made fully. Why bother? It would be a waste of time and energy trying to put in place that last few per cent of self-sufficiency. Probably getting to 90% self-sufficiency and knowing you can do the rest if necessary within say 5 years, would be enough to guarantee you have a "back up planet". As long as you can trade goods and services with Earth, you can buy Earth products.

I think making computer chips might be easier than you think, doing it robotically (same for PV panels). But putting together a rocket? That would require a lot of human involvement and oversight...that said I suppose strictly speaking you don't need a rocket if you are self-sufficient.

Terraformer wrote:

Getting to 99% self replicating is going to be a lot easier than 100%. There are certain things essential to modern technological society which are low mass, high value items. Things like computer chips. How long will a tonne of computer components last? There are alternatives, of course - vacuum tubes, relays etc - but there's a reason we replaced them with microprocessors. Rather than building a chip fab, it might make more sense to ensure several decades worth of chips are in storage.
That said, we probably could build a civilisation on Mars with Mercury era technology. But we wouldn't have 3D printers to make things easier. It would be like the Nazi moonbase in Iron Sky. Still, it's a level that they could subsist at if we blow ourselves up and there are no more imports of Terran goods.
Of course, if Mars turns out to be easy to proteroform (thicker atmosphere, warmer, liquid water), then things become a lot easier. No need for pressurised greenhouses - heated polytunnels would do. Oxygen extracted from the atmosphere. Worse dust storms, but also more prospect for wind power. Much simpler suits for working outside. Canals for transport.

Spaniard · 2018-07-03 08:44:10

I think that there is some interesting concept around this. A colony doesn't need in fact to be a human (manned) colony. It could be a robot colony.
Of course, human colony is own true goal, but a robot colony means production so it could growth mainly without direct human intervention (so, present on the planet/moon)

The idea is to decouple mass from production capability as fast as possible. Because moving mass meaning move a lot of mass, and mass implies big rockets and careful plans, this way is very slow.

When a colony machine exists, one machines could fix or change other machines, through IA or remoted controlled. We can have a remoted controlled colony on the Moon without have any astronaut there in fact, but a lot of people involved on Earth doing plans testing on simulation and trying frequently instead of use non-tolerant to faults missions.

Though that approach, we could create a exponential production capability with a constant effort (that it's what we will have on a limited Earth)

RobertDyck · 2018-07-03 08:52:07

Today you can buy a desktop printer for Printed Circuit Boards. All you really need are chips.

louis · 2018-07-03 09:11:21

Yes, I think the colony would be heavily dependent on robotics. Here are a few areas: agriculture, food processing, cooking, cleaning, transport (driverless rovers), mining... We basically have robots already in all these areas. They just need to be tailored for Mars.

The only real problem with robots is that they are sophisticated products, which are not easy to replicate - so it is a heavy investment for a small colony to produce robots, but I think it does need to be done.

I don't think we are quite at the point where robots can do the intricate maintenance work that humans are very good at but part of the colonists' plan should be to try and simplify processes so that robots can undertake work. Cleaning is an obvious one. It makes sense to have smooth relatively hard surfaces that robots can easily clean.

One of my favourites is this robo-chef:

https://www.youtube.com/watch?v=mKCVol2iWcc

No need for human chefs on Mars!

There are also now robo GP doctors who can assess their patients' illnesses more accurately than human doctors. They will be v. useful.

Spaniard wrote:

I think that there is some interesting concept around this. A colony doesn't need in fact to be a human (manned) colony. It could be a robot colony.
Of course, human colony is own true goal, but a robot colony means production so it could growth mainly without direct human intervention (so, present on the planet/moon)
The idea is to decouple mass from production capability as fast as possible. Because moving mass meaning move a lot of mass, and mass implies big rockets and careful plans, this way is very slow.
When a colony machine exists, one machines could fix or change other machines, through IA or remoted controlled. We can have a remoted controlled colony on the Moon without have any astronaut there in fact, but a lot of people involved on Earth doing plans testing on simulation and trying frequently instead of use non-tolerant to faults missions.
Though that approach, we could create a exponential production capability with a constant effort (that it's what we will have on a limited Earth)

louis · 2018-07-03 09:14:17

Interesting. And it looks now like chip manufacture is highly automated.

RobertDyck wrote:

Today you can buy a desktop printer for Printed Circuit Boards. All you really need are chips.

louis · 2018-07-03 15:48:23

Another way of approaching this problem is to make a checklist of all the things that are not strictly necessary to a self-replicating hi-tech colony. These stand out for me, as items that globally on Earth use a lot mass and could be dispensed with nearly 100%:

- Paper
- Tarmaced roads
- Carpets
- Curtains
- Paint

In other areas, manufacturing processes could be drastically simplified. For instance, on Earth there are probably 100,000s of glass bottle shapes used on Earth. That could be reduced to perhaps about a 100 glass receptacle designs.

SpaceNut · 2018-07-03 17:27:23

Molds are made to make the many unique shapes with a wide variety of glasses but while a mason jar is fine to can or to drink from like a cup its just not a very go bowl for you breakfast cereal.
The real trick is not just to simply down the choices what can be made but to look at how to make the various steps for machines that can do multiple tasks to make that glass and to make the mold shapes.
Commonality of insitu resources, processes, ect to utilize the most out of having the machine.

louis · 2018-07-03 19:02:25

Amazon has some 480 million product items in their warehouses. I think we can agree that they are not all necessary to make a self-replicating colony. You do need to make some choices.

I agree you want to use flexible machines as far as possible, but I think you also need to know what you need to produce, and when it comes to say glassware, I think that means a much narrower range of items.

I am not particularly recommending this approach. I think the way things will go will be more a mix of conscious planning for self-reliance, commercial forces, and trade with Earth, meaning continued, substantial imports.

But this is an interesting thought experiment, as I think it does focus attention on what self-replication means and requires.

SpaceNut wrote:

Molds are made to make the many unique shapes with a wide variety of glasses but while a mason jar is fine to can or to drink from like a cup its just not a very go bowl for you breakfast cereal.
The real trick is not just to simply down the choices what can be made but to look at how to make the various steps for machines that can do multiple tasks to make that glass and to make the mold shapes.
Commonality of insitu resources, processes, ect to utilize the most out of having the machine.

SpaceNut · 2018-07-03 20:39:54

Machines in general need very little glass other than for optical lenses.

Next after metals for construction of the machine we need to be able to make electrical items as in the components to make chips if we can but I think that is a second teir and should wait for the machine army to be made from ready made parts to make the machines work.

So after making more machines the next teir should be making shelters and stuff for humans to make use of.

louis · 2018-07-04 03:46:56

Yes, glass is an interesting issue.

It's true that it's not much needed in the industrial infrastructure, but on the other hand I have tended to think it is something that can be produced more readily on Mars than plastics, and so it might make sense to revert to glass use for a lot of food packaging and kitchen ware.

From previous discussions, I think a self replicating colony could cope with construction well: the colony can use ISRU to make bricks (even compressed bricks), steel supports, cement or concrete and glass for windows (where required) - basalt tiles could be used for flooring and finishing off walls. The key issues there are probably labour shortage and life support.

Construction is still, in this very automated age, v. labour intensive and would likely be even more so on Mars unless we found robotic techniques that would work. There are of course robotic building techniques being trialled. I think also use construction habs to provide a temperature and pressurised, controlled environment for construction would help. Robots can lay bricks. They can also extrude cement or concrete to make buildings. Building larger domed structures would perhaps be more challenging although I suppose there is really no reason why robots could cope with putting together triangular glass panels.

Life support is a pretty hi tech affair that needs to be technically robust and reliable - processing, storage, seals, homeostatic controls, pumps, alarms, electrical wiring...No doubt a Mars colony would have a manufacturing facility dedicated to producing high quality life support for a range of habitats: home habs, agriculture, rovers, exploration, way stations, air locks, transport storage...Plumbing can probably be regarded as a part of life support on Mars. It needs to be far more reliable and quick fix than on Earth! Faulty plumbing in a Mars context could be fatal if you had a serious water leak. Probably means your plumbing system has to be far more exposed than on Earth, capable of quick repair and isolatable in sections. You don't want plumbing buried or inaccessible.

SpaceNut wrote:

Machines in general need very little glass other than for optical lenses.
Next after metals for construction of the machine we need to be able to make electrical items as in the components to make chips if we can but I think that is a second teir and should wait for the machine army to be made from ready made parts to make the machines work.
So after making more machines the next teir should be making shelters and stuff for humans to make use of.

louis · 2018-07-04 09:40:57

Robot farming -

Check out 00:30 to 11:50

https://www.youtube.com/watch?v=JPvjucZPZLM

This is pretty much how I see Mars agriculture taking place - largely automated.

For a 100,000 person colony you need to grow about 55,000 tonnes of food per annum. If that were all from an annual wheat crop you'd need about 150 million sq. metres of land on Earth or about 12.5 kms by 12.5 kms. Energy requirement might be somewhere around 525 Gwhs per sol translating to an average of around 42 GWs constant during sol-light hours. That is nearly half the UK electricity generation capacity. Obviously there are other food crops apart from wheat and some coming produce multiple crops per annum. But even if we reduce that 42 Gws by 80% it's still a huge energy requirement that it would be difficult to install and maintain. So I think natural light farming will certainly be required once the colony gets beyond a few hundred.

Terraformer · 2018-07-04 12:04:32

louis wrote:

Another way of approaching this problem is to make a checklist of all the things that are not strictly necessary to a self-replicating hi-tech colony. These stand out for me, as items that globally on Earth use a lot mass and could be dispensed with nearly 100%:
- Paper
- Tarmaced roads
- Carpets
- Curtains
- Paint
In other areas, manufacturing processes could be drastically simplified. For instance, on Earth there are probably 100,000s of glass bottle shapes used on Earth. That could be reduced to perhaps about a 100 glass receptacle designs.

We might not be using those - though do you really want to dispense with tissues and paper towels? - but we definitely need the capability to manufacture them. We need sealants. We need to be able to produce complex long chain hydrocarbons. We need to be able to produce cloth, for bedsheets clothes etc. Cellulose has lot's of uses, and we need to be able to process it. In order to be self replicating, we basically need to be able to produce anything currently produced on Terra, *even though we'll only be producing a small subset of those things.*

If your society can't build a car from scratch, you don't have a technologically complex society, because you lack the ability to smelt iron, produce steel, extrude wiring, build motors... but the ability to build a car doesn't require you to actually use cars, since the required skills can also be put to use build railroads and trains to run on them.

RobertDyck · 2018-07-04 15:18:15

I would suggest honey bees for pollination. The reason is they are the only pollinator that produces honey. But there's technology for that too. There is technology to count bees leaving and returning to a beehive. A modern apiary can use a solenoid to close a door, locking bees inside. The apiary (structure containing beehive(s)) can then be transported to a different field or greenhouse. Swing door (flap valve) creates a one-way exit or entrance, so bees can be allowed to return but not leave. Once the counter confirms all bees have returned, it's closed. You probably don't want greenhouse workers inside when honeybees are doing their work. Only trained beekeepers should be in there with bees.

Honey bees can fly 15 mph, so a human entrance tunnel with fans blowing a stiff breeze faster than that into the greenhouse would ensure no bees can get out. Even when workers enter/exit. Obviously the breeze is not necessary when bees are not in the greenhouse.

"Forcipomyia squamipennis" is the scientific name for a species of biting midge that is the natural pollinator for cacao trees. Their seed pods produce cocoa to make chocolate. These midges fly can't fly faster than 7 mph, so a human at a fast walk is faster. The wind tunnel thing to contain them is even easier, because breeze speed can be slower.

Last edited by RobertDyck (2018-07-04 18:25:09)

louis · 2018-07-04 15:40:10

I think most clothing, sheets etc would be cotton based. A colony should have no problem producing cotton. Furthermore cotton can to a certain extent be recycled. In a pressurised temperature controlled environment, there should be no, or little, need for v. warm clothing. Again that cuts down on the need to produce textiles.

Well your choice of a car is a good example. Yes, the colony will need transport. But does it need the internal combustion engine or a diesel engine or a coal fired steam engine? I'd say no. Electric motors and batteries can do the job. There is I think an argument for natural gas (methane) electricity generators but not for methane engines for transport, I think.

Health treatment is another area where a self-replicating colony doesn't need to do the full range (which is not to say it won't provide them, possibly through importation from Earth). Basically, communities self-replicated over tens of thousands of years with very basic health care. On Mars with good standards of hygiene the massive disease problem of previous centuries - such as bubonic plague, cholera, typhus and the like. Likewise with good standards of nutrition there would be none of the malnutritional diseases like rickets. With genetic checks on procreation, virtually a large proportion of genetic diseases could be prevented. So even without the full range of medicines and medicinal health procedures you would have a pretty healthy population that could sustain the colony. But to replicate what we do on Earth in terms of the thousands of medicines and treatment procedures (including of thousands of surgical interventions)? That would be a tall order for a smallish colony of 100,000. Wikipedia lists 55 main specialities in medicine recognised in the EU:

https://en.wikipedia.org/wiki/Specialty … nomic_Area

Each one is quite a broad category and likely has several sub-specialisms within it.

So some guesstimates. In order to provide and maintain such services to anything approaching a high standard you'd probably need at least 100 teachers/specialists/juniors/students and support staff for any given speciality, plus a huge amount of specialist equipment. That would be a minimum of 5500 out of your 100,000 (of whom maybe only 80,000 would be adults, theoretically available for such work). Many more would be engaged in producing the full range of hi-tech equipment needed to deliver the services to a high standard. Hazarding a guess, that could be thousands as well involved in production, quality control and so on.

But what would be the size of the health problem? In the UK about 25% of the population now has diabetes? But on Mars, with a selected population of very healthy people with a commitment to maintaining fitness, the figure might be far lower maybe more like 1%.
And of those 1% probably a large majority would have scientific understanding and willpower to cure themselves of Type 2, through diet changes and so on. The problem for a Mars colony is that although the patient base might be low, you still need to have a high staff-speciality ratio in order to maintain standards of service delivery and depth of knowledge. There might be virtually no STDs on the planet for instance, but if you want to cover that area, then you need the full range of humans with specialist knowledge.

Of course, until the era of jet travel, this was a problem that beset many small isolated communities. The nearest decent hospital could be hundreds or even thousands of miles away. This is still an issue in Africa of course. The harsh truth is that people died for lack of high quality health services, and their passing was managed as best as local health practitioners could provide.

I think it is simply impossible for a small Mars colony to achieve an across the board high standard health service as you find in the USA or Western Europe covering everything from cancer to corns. Some things will be easier to provide than others. Robot GPs are good at diagnosis as are robotic blood tests. Clearly the colony will have to be good on bones and muscles and other space medicine specialisms. If it wants to ensure a continuing population it will have to provide good fertility, ante-natal, maternity and post natal care.

The reality I think is that Mars will be very reliant on medical advice from Earth. Probably specialists on Earth will interact with robots and general practitioners on Mars undertaking observations and discussing notes. The time delay is an unfortunate impediment to making this an easy process. The Mars colony will not attempt to replicate the full range of specialisms. It will focus on basic health (good hygiene, diet, medical supervision), basic surgery (fractures and so on), space medicine and procreative medicine.

Robo surgery may make more sophisticated surgery on Mars a possibility. We're not at that point yet.

Terraformer wrote:

louis wrote:
Another way of approaching this problem is to make a checklist of all the things that are not strictly necessary to a self-replicating hi-tech colony. These stand out for me, as items that globally on Earth use a lot mass and could be dispensed with nearly 100%:
- Paper
- Tarmaced roads
- Carpets
- Curtains
- Paint
In other areas, manufacturing processes could be drastically simplified. For instance, on Earth there are probably 100,000s of glass bottle shapes used on Earth. That could be reduced to perhaps about a 100 glass receptacle designs.
We might not be using those - though do you really want to dispense with tissues and paper towels? - but we definitely need the capability to manufacture them. We need sealants. We need to be able to produce complex long chain hydrocarbons. We need to be able to produce cloth, for bedsheets clothes etc. Cellulose has lot's of uses, and we need to be able to process it. In order to be self replicating, we basically need to be able to produce anything currently produced on Terra, *even though we'll only be producing a small subset of those things.*
If your society can't build a car from scratch, you don't have a technologically complex society, because you lack the ability to smelt iron, produce steel, extrude wiring, build motors... but the ability to build a car doesn't require you to actually use cars, since the required skills can also be put to use build railroads and trains to run on them.

SpaceNut · 2018-07-04 15:44:25

Paper requires some sort of living cellulose pulp which means a greenhouse that is not being used for foods or from a crop that the stocks are not eaten for this fiber pulp to made from.
Crush/cracked sub inch sized stone will most likely be favored for mars roads for quite some time.
Carpets and curtains can and are made from plastics along with lots of other things.
Not sure we will need much paint unless its just to add color.

louis · 2018-07-04 18:00:06

You can make paper from bamboo, much faster growing than trees but I agree with your point about greenhouse space being v. valuable. It should be used for food and textile plants, not feeding unnecessary industries.

We have ice roads on Earth and you are pretty much driving on frozen ground in many places. There may be some parts where you need to lay some sort of surface. But I would hope in many places that it's simply a question of removing boulders and flattening the ground nicely with a big roller.

SpaceNut wrote:

Paper requires some sort of living cellulose pulp which means a greenhouse that is not being used for foods or from a crop that the stocks are not eaten for this fiber pulp to made from.
Crush/cracked sub inch sized stone will most likely be favored for mars roads for quite some time.
Carpets and curtains can and are made from plastics along with lots of other things.
Not sure we will need much paint unless its just to add color.

RobertDyck · 2018-07-04 20:26:30

louis wrote:

I think most clothing, sheets etc would be cotton based.

There will be cotton, but I think you underestimate the value of synthetic fibres. Remember, natural fibres on Mars require a pressurized greenhouse. And that either requires a lot of manufactured nutrient solutions for hydroponics/aeroponics, nor processed soil. Mars soil is suitable for agriculture, but you have to decompose the perchlorates, add nitrogen fertilizer, and most crops require organic content in soil. I continue to argue for ambient light greenhouses, some crops will require mirrors to increase light levels, but during a dust storm they will require artificial light. Compare all that to manufacturing synthetic fibres. Some fabrics on Earth today are made from recycled PET. Other major fabrics are polyester and acrylic. Rayon is made from natural cellulose, and doesn't age well. Nylon is sensitive to heat, so must be washed and dried on cool settings. Spandex is elastic, so used for special purposes.

SpaceNut · 2018-07-04 21:10:54

Dutch city's 3D-printed homes could help upend the construction industry

Project Milestone will put concrete printing technology to the test. Of course next would be Marscrete....

180615-project-milestone-eindhoven_al-1049_6ab55919904433a15e72ae8cb806a6ae.fit-2000w.jpg

180625-mach-3d-printing-house-nozzle-se-1217p_038f9a67f4ca8c34c2590325a222efd4.fit-560w.jpg

Next up is the https://www.nbcnews.com/mach/science/so … ncna848646

louis · 2018-07-05 04:07:38

Very interesting. There are a number of robotic construction techiques that are worth investigating for Mars. I am sure that part of the key on Mars will be creating a temperature controlled and pressurised construction hab to allow the construction to proceed in Earth-like conditions.

Regarding brick layers (noting the Dutch shortage) there are robot brick layers:

https://www.youtube.com/watch?v=2-VR4IcDhX0

(See from 0:22)

Then we have possibility of robotically producing compressed bricks from Mars regolith, with no firing required:

https://www.theverge.com/2017/4/27/1543 … n-missions

Robots could very likely produce simple habs resembling Victorian ice houses that could then be covered with regolith for radiation protection. I referenced these previously - here's an example:

http://www.moseleypark.co.uk/ice-house/ … mb-jpeg-2/

SpaceNut wrote:

Dutch city's 3D-printed homes could help upend the construction industry
Project Milestone will put concrete printing technology to the test. Of course next would be Marscrete....
https://media2.s-nbcnews.com/j/newscms/ … -2000w.jpg
https://media3.s-nbcnews.com/j/newscms/ … t-560w.jpg
Next up is the https://www.nbcnews.com/mach/science/so … ncna848646

louis · 2018-07-05 05:01:53

Robert,

Yes we need to be careful about how much of agricultural land is given over to textiles. There is a balance to be struck. Cotton can be recycled for other textiles but cotton-synthetic mixes cannot, as I understand it. Synthetic fibres will certainly have a role to play, not least in producing space suits - one of those hi-tech challenges for a small colony.

I think a Mars colony colony might wish to manufacture soil "from scratch" as it were, avoiding perchlorates. Pristine rock can certainly be crushed to create a "parent material". In terms of mineral content, sand or crushed sandstone can also be added, along with ancient silts and clay (either dug from beneath the Mars surface or manufactured in the lab). Could we also extract carbon from the atmosphere and make something like peat to add to the mix? Nitrogen for fertiliser could be concentrated from the Mars atmosphere (perhaps as a by-product of life support ops) with each cubic metre containing about 0.0015 kgs (so, a 100 metres cubed would produce 1.5 tonnes of nitrogen) . Nutrient solutions might initially have to be imported from Earth. But many could be produced on Mars. Thereafter, we probably need to create a benign ecosystem, involving certainly worms - and maybe your bees.

Here's an interesting article on synthetic soil - seems some people are taking an interest:

https://www.nextnature.net/2012/05/comp … etic-soil/

RobertDyck wrote:

louis wrote:
I think most clothing, sheets etc would be cotton based.
There will be cotton, but I think you underestimate the value of synthetic fibres. Remember, natural fibres on Mars require a pressurized greenhouse. And that either requires a lot of manufactured nutrient solutions for hydroponics/aeroponics, nor processed soil. Mars soil is suitable for agriculture, but you have to decompose the perchlorates, add nitrogen fertilizer, and most crops require organic content in soil. I continue to argue for ambient light greenhouses, some crops will require mirrors to increase light levels, but during a dust storm they will require artificial light. Compare all that to manufacturing synthetic fibres. Some fabrics on Earth today are made from recycled PET. Other major fabrics are polyester and acrylic. Rayon is made from natural cellulose, and doesn't age well. Nylon is sensitive to heat, so must be washed and dried on cool settings. Spandex is elastic, so used for special purposes.

RobertDyck · 2018-07-05 13:36:42

Manufacturing soil "from scratch" is a bigger job than you realize. It requires grinding rock to the consistency of flour; it's called rock flour. Then decompose the rock flour to create clay and release nutrients: sodium, potassium, calcium, magnesium. Nature uses moving water over millions of years, it can be accelerated with acid. Peat is a symbiosis of sphagnum moss with a variety of cyanobacteria. That moss produces acid, specifically designed to decompose rock to release nutrients. However, peat normally takes thousands of years. Grinding to rock flour first would accelerate the process, but I tried it in an aquarium. It released so much calcium and magnesium that it converted the water to alkali, killing the peat. Doing this with peat requires an active means to remove calcium and magnesium. When the peat is finished decomposing rock flour, the calcium and magnesium would have to be added back to neutralize the acid. And plants require those nutrients, for one they use a single atom of magnesium for each molecule of chlorophyll. Humans use both calcium and magnesium for bone, so it has to be in our food.

Nitrogen fertilizer can be simple ammonium-nitrate. It was used for decades as fertilizer on Earth. It was regulated after the Oklahoma bombing, but the guy who did that had special forces training specifically to use readily available materials to take down a building. Farmers used ammonium-nitrate with diesel fuel to blow up tree stumps, but they certainly didn't and still don't know how to use that to take down a building. This is another example of government taking extreme and inappropriate action. They should have acknowledged that the Oklahoma bomber was trained by US military special ops to do exactly what he did. The man was discharged from the military, but still had the knowledge. Instead, normal fertilizer used for years for lawns and more importantly used for agriculture is now heavily regulated. On Mars we won't have to deal with that, no regulation over fertilizer. I could post how to make ammonium-nitrate from nothing but air, water, electricity, and equipment you could buy at a hardware store, but if I did government officials would have a cow. Let's just say it can be done.

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Self-replicating colony - a challenge but how difficult?

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