So given an Earth in our near future, year 2100 or so, where some of our tech has improved to the point where we have robots and the usual sci-fi devices for interfacing with computers.

A colony is dispatched to a new "earth-clone" planet and it's a one-way trip with no communications possible with Earth. They knew this from the start. This planet is not hostile in any way. There are edible plants to farm and docile cattle-like animals to domesticate. The starting population is 100 people with mixed skills and education. They arrive with some building supplies for their shelters and a few replacement parts for some of their key tech and power generators (solar&wind).

With the eventuality that their tools and replacement parts will be depleted. How long before this colony can create relatively "simple" items like metal tools and clothing? How long before firearms and ammo? How long for electronics? How long for computer components?


  • $\begingroup$ Would be stupid to reach the destination totally unprepared, with no trace of energy and technology to bootstrap the development. Some compact fission reactors are likely to be taken to be used at destination (assuming no compact fusion reactors are invented by then). And robots - which, btw, do not necessarily mean humanoid robots, can be manufacturing ones - 3d-printing capabilities and such $\endgroup$ Apr 20 '20 at 17:53
  • $\begingroup$ Hey, thank you for the response. But even those things they would bring would "wear out". $\endgroup$
    – John
    Apr 20 '20 at 18:01
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    $\begingroup$ Well, Renault came in the Socialist Republic of Romania in 1965, began building an automobile industry from scratch, and ten years later Romania was producing automobiles with all components sourced from the domestic market. And they didn't have artificially intelligent molecular fabrication units, self-aware universal robots, artificial wombs, autonomous agricultural production units, high-speed brain-computer interfaces and so on. Seriously, you are grossly underestimating the technological advances required to bridge interstellar distances. $\endgroup$
    – AlexP
    Apr 20 '20 at 18:09
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    $\begingroup$ How many robots do they have and how capable they are? Without robots, by answer would be somewhere in the ballpark of 500 years. $\endgroup$
    – Alexander
    Apr 20 '20 at 18:15
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    $\begingroup$ This seems very similar to a question I asked awhile back. Mine was about an unplanned colony but I think with the details provided and the scenarios involved it's a very closely related but not quite duplicate question. $\endgroup$ Apr 20 '20 at 19:05

All of the items that you mentioned could be very easy or difficult to re-create on your planet. There is a primary issues working against you: Even if a planet is "Earth-like," the difference between it and Earth can be like night and day (both literally and figuratively). While the atmosphere may be able to sustain human life, it is unlikely that the amount of resources would be similar to that on Earth. Even these "cattle-like" animals could be inappropriate for human consumption; this is based on realistic likelihood. Ultimately, it's your story. YOU make the rules. Depending on which elements are more plentiful on this new planet, this could create A LOT of problems too.

I'm sorry, but there's no reasonable answer for this without taking various specifics into consideration. Your colonized planet seems pretty lazily made (no offense), so it sounds like most of the resources and elements on Earth would be just as plentiful there. Taking that into consideration, you're looking at a matter of months for every single item that you mentioned. Some of them would only take days, and that would include the procurement of the components used to create them. I imagine clothing and metal tools would be the easiest (the term "metal tool" is very broad though and could be a very simple item or very complicated). If your planet is an Earth clone, keep in mind that since the population would be NOTICEABLY lower, most resources would be abundant by comparison.

On the other hand, if some resources are more rare, it could take several years for the simplest of items. Various Earth-like items might require a knowledge of chemistry to combine the appropriate elements found on the planet to create them. If those elements are in short supply... there's your problem. I imagine that this new colony would use various substitutions based on availability. They'll probably have to get pretty creative.

As an aside, it's also incredibly important for you to focus on the skills of your population. I'm not sure what you meant when you said "mixed skills." There would have been a tiring amount of studies done on this planet prior to setting foot there. If Earth is going to be colonizing anything, we would send some of the brightest minds of humanity. There would be no shortage of scientists and engineers. People will get sick and injured whether they're on Earth or on some colonized planet, so doctors too... And it's likely that some type of "military presence" would be dragged along. What about family members or even just people who are there for the ride? The 100-person population is not viable. And the population would DEFINITELY have people with the knowledge to attempt to re-create just about anything found on Earth.

  • $\begingroup$ Thank you for the responses. My thought experiment boils down to the time it would take to get back to the point where they could manufacture the things they brought with them. Let's say their robots can manufacture things. Where do the colonists get the supplies? What happens when the robots break down? They would repair them of course. Using up supplies like ... duct tape, or what have you. So what would they do when they run out of duct tape. Ballpark of 500 years seems like a reasonable starting point considering how small the colony is in my example. $\endgroup$
    – John
    Apr 20 '20 at 18:57
  • $\begingroup$ That goes back to by answer. Using your example of duct tape, are the necessary materials to make duct tape readily available (cotton, polyester, nylon, etc.)? Are they capable of easily producing polyethylene? If so, you certainly won't need anywhere close to 500 years. Realistically, a population would focus on sustainability. If they don't have the materials, they will substitute or create something else entirely to supplement their needs... You should really narrow down what resources are available in this new world. $\endgroup$
    – Rauri
    Apr 20 '20 at 19:56
  • $\begingroup$ Of course, elements can be combined (chemistry) to form other materials, but if those elements aren't available to begin with, there's nothing the people can do about that other than rely on substitutions or get creative. $\endgroup$
    – Rauri
    Apr 20 '20 at 19:56

Summary: They'd be able to bring most of our current technology along in a self-sustaining fashion.

I think this question overestimates what it takes to set up a self-sustaining technology base. While we can't do it yet with our current technology, I think it's entirely reasonable that we would be able to do so in 2100. Especially as we can assume that these colonists made the necessary preparations before departing.

3D printers designed with self-replication in mind are already capable of printing most of their own components. The most difficult to replicate parts are probably computer chips, motors, and printer heads that can withstand high temperatures needed to print metals, so for such components dedicated manufacturing machines will be needed. These dedicated machines can also for the most part be made of 3d printed components.

With year 2100 sci-fi in mind it's not at all a stretch to imagine that the colonists will take a bunch of machines and robots with them that can replicate themselves from raw materials. They will also have a large library of designs for other machines that they can 3d print / cnc-mill, depending on what they need in the colony, that have been tested back on earth. This library would include at least designs for larger 3d printers, so they can scale up their industry where appropriate, and designs for machines for a large variety of smelting and raw materials processing pipelines.

All that they will need to find on their new planet is the needed raw materials. Some chemical elements can be expected to be common on any rocky planet, also in other solar systems, because the general principles of nucleosynthesis and of planet formation are the same everywhere in the universe. The machines and designs that they bring along will as far as possible be based on such common elements, or will have backup designs that can be used if some rare element is not available.

The most difficult part therefore will be to find deposits of all necessary chemical elements and have the necessary transportation available to bring all the resources together in a manufacturing facility. But there's nothing that can't be done with 22nd century technology. The current Earth economy is already a self-sustaining technology base, all that is needed is automation and miniaturization of the essential technologies.

What the colonists will bring with them is therefore the machines needed to get to self-replication, and enough raw materials to produce whatever is necessary to start the initial mining operations (or maybe some pre-assembled machines for that). Most likely the colonists will take extra stock of rare materials that may be hard to find and which (hopefully) are only needed in limited quantities (e.g. rare earth elements), and only limited stock of elements which are common on earth-like planets such as aluminium, silicon, carbon or iron.


I think the colonists would be in a lot of trouble, but the devil is in the detail. It depends on so many different assumptions such as do the colonists know where to find all of the materials they need? What transportation do they have available and how is it powered? What is the mix in skill and education? How long will a few replacement parts last for?

Firstly clothing: this should be relatively simple at least initially – grow the right crops and harvest the fibres using basic tools manufactured from simple locally found materials such as wood (looms, spinning wheels etc) plus imported tools made of steel. But the steel will eventually blunt, break or where out, this might take a long time but they will need replacing eventually.

So how about steel? This is more problematic but should still be possible. They need to find a source of iron ore that is readily accessible and perhaps some limestone, (charcoal can be easily made from wood) then create some sort of crude furnace, leather bellows and a clay lined hearth perhaps but that will only get them iron not steel. True steel is going to need an oxygen supply and a lot more processing.

So simple metal tools and clothing yes, steel not immediately.

Fire arms? If you have iron it should be possible to fashion a crude cannon, but proper gun powder would be problematic. Assuming that a source of sulphur is available locally, charcoal can be made and potassium nitrate can also be sourced from dung, but purification and granulation would be difficult. The resultant firearms would be dangerous and unreliable.

Electronics would be a long long way down the technological tree and would not be available for many years or decades. The reason being that they require so many different materials that have to be found and then processed in complex ways, with equipment that also needs to be created somehow. As for computer components they would be even further down the tree.


A few * years, at most.

They will have prepared for the task.

They will have access to a vast library of skills, blueprints and manufacturing steps. They will not have to invent anything, merely find the resources and the tools to work the resources.

And by far the most important: They will set up their settlement with a fully equipped machine shop. Drills. Lathes. Smelters. Motors. Power generators and transformers. Plenty of electrical cable. A nice stock of rare-earth magnets. Many many computer components(many because they are among the most difficult to manufacture, and can be packed in a very tiny space massing almost nothing)

It was an old blacksmith trope that "To build a forge, you just need.. a forge".
It is an old engineering trope that "To build a lathe, you must have a Lathe". Although precision measurement tools will help, a lot!

Take one skilled engineer with his complete engineering toolshop into Roman times, and he can duplicate his toolshop within 10 years. Or build a steam engine, etc.
Take the same man without his tools, and he will be lucky to even get started before dying of old age.

* few: It could be a generation or two.
They will need to locate, and mine minerals and metals.
While doing this, they will need to build farms, so they don't starve.
(It helps a LOT if they bring along robots capable of doing this. Don't need a lot of farm to feed 100 people, if you have skilled tireless 24/7 workers that don't eat what they produce)
Politics and squabbles will factor in.
Health might be an issue.
100 people is not a lot. They might very well run out of available bodies to perform all the needed survival jobs.


Never or the same moment they have arrived.

They have the technology of recreating production capacity, then it more or less straightforward push the button thing, and just takes time to locate additional resources if they require expansion.

if they do not, then even keeping 1800's tech will be problematic over the 100+ years.

I would say it takes about 20 differently skilled people to raise one skilled guy, based on my past experience. Specializations do overlap - like basic math is useful in all sort of fields but there are different fields of math which are more specific and each needs a guy, fundamental knowledge about chemistry and then I would say you need at least one guy for each of about at least 10 specializations of chemistry which one needs for industry, physics - school level that is one guy, but then flavors of it to which there is no end.

The number of different knowledge required to keep wheels rolling for the current technological system is just insane - a lot.

The number of different job titles, professions can be estimated by some googling like "list of job titles in manufacturing" or similar - didn't have great success with finding some good place to link, this one isn't that bad https://www.bls.gov/ooh/ but requires specific IP addresses, others are less comprehensive. But I would guestimate like 500 job titles, but it just estimation on one site and do not think it comprehensive or detailed enough, so as you need few guys for each - junior, professional and senior in each category, as there is a job for all of them, so you need management as well. yes, some data scientists may be less relevant in the context of recreating steam era tech, but hey, where all the drawings come from, and how do you adjust them to your current need and maintain your original database.

But current specialties are not only ones such situation may require - in case of bootstrapping the technologies - it requires skills and expertise from past of the development of those technologies. working with vacuum tubes - is almost a lost art, even if it was common knowledge not so long ago, but today same TTL voltage or die. How cloth was made back in the days of a primitive era - only roleplayers know.

if your guys have to work, they do not have that much time to teach, not speaking about that doing and teaching are not the same activities - some can, some can't combine both.

So if we consider it all more detailed and the number of people required easy can swell from 100 to 10000 of geniuses people with mixed skills and education, maybe not geniuses but 120+ for sure. But next-generation won't be all 120+, genetics, sperm and eggs do not care about your needs. So to keep the presence of those smart people in sufficient quantities, do multiply it by another 10-20.

  • if we skip cloning and artificial wombs, if not then some reduction coefficient can be squeezed from that.

And this way, if one digs it then it can be seen that 100 people is just not a starter no matter how you spin it if your goal is returning back to the technical capacity of your home. if primitive life is the goal then they all have survival training - all they need, and few thousand years later if they are lucky and do not die out and sail smoothly through the times they can get to our current time, do not forget your new technobible testament, however.

if they do have a technology to bootstrap technology

Then things are somewhat simpler. But then they do not have a situation of spare parts running out, nor do they need them as some big stock of them - what do they need is energy and resources materials elements. A broken part is not a broken part but an ore of elements they need to produce a perfectly working new part - so recycling is a king.

They need some system of equipment which can produce parts and components for each other. robust database - which keeps all the technological howtos, described in terms of that system and its automated capacities, and related information to resource gathering which fits the planet and equipment required for produce the equipment which does the resource gathering.

They need a lot of automatic - for servicing, for expansion, for transportation etc.

Steady energy source, a lot a lot of energy which is ready on demand and energy management systems to not run out of energy at critical moments of production. Fusion would be nice, D-fusion - then they will have no problems at any place suitable for humans. Energy from space also can be a good thing, SBSP, as they come from it then why not - it would help them a lot, and isn't that hard to establish if you already in space and all the technological capacities at hand.

Then the function of those guys is the management of the system, it still may require a good amount of brain cells and a wide variety of skills and knowledge.

Number still may be too low, but maybe, and for sure they also have to have automatic teaching systems, external means to transfer and imprint the required amounts of knowledge to next generations. This will be a very rigid system - no occupation changes allowed - for next generations it is, as you will need to squeeze it all from some 80 points individual, the same way as from a 100 or 120 guys and place them to proper occupations in that management system, you can't waste any human-like brain power and it still does not prevent the chances for them to drive that technological ship into the ground, because of lack of understanding what they do. if 100 people are enough to manage the system then again it needs more people or other ways to increase the numbers to guarantee to have the same quality of management in the future.

if we imagine some good AI assistance then 100 is enough and even one guy is sufficient. And then it less about people numbers but more about the social stability of the system which will define its future development and story.


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