6 ms·

A metallurgist's doubts about self-replicating probes

158 points by EA-3167 3mo ago

zeryx 3mo ago
I studied material science in school specifically to try and address his concerns. Unfortunately they are all quite valid - the hard part isn't manufacturing, extruding, printing. Those are actually all quite reasonable (albeit not super space or weight efficient). The hard part is refining and ore enrichment, and most techniques that could possibly work in microgravity are almost impossible to test on earth. You would certainly need vitamins for electronics components for a time. Even much older computer chip architectures (1990s level) still require the clean room and 20-30 stages of prep. I believe an orbital chip fab is not only possible but, kind of ideal? Keeping it clean would be within reach - and it's mostly if not entirely an autonomous process from silicon monocrystal to assembled part today. We're along way from self replicating probes. But I would argue were quite capable of autonomous mining, manufacturing and material transport - assuming we can figure out how to refine effectively. If someone wants a cool PhD project and ship an experiment to the ISS, I would argue an ionic or plasma based refining technique designed for micro gravity could be very interesting and very useful
- Animats 3mo ago
  > Every terrestrial concentration process relies on things an asteroid lacks: gravity-driven sedimentation, water-based flotation, density separation in fluids, atmospheric combustion. That's a good point. Most bulk industrial processes won't work in zero G. This limits asteroid mining. Breaking off pieces of rock and accelerating them to somewhere, maybe. Building a big wheel and spinning it up to get some gravity, maybe. Materials processing in open space, not so much. The "seed" to start up an industrial economy might be the size of the industrial base of, say, Israel or North Korea, both of which try to be self-sufficient. We get to find out when someone tries to do something self-sustaining on Luna or Mars.
  - neaden 3mo ago
    "Israel or North Korea, both of which try to be self-sufficient" - Neither of them do any such thing though. From a quick search Israel imports about 80% of their calories though they also export some food they are heavily reliant on imported grains and meat. North Korea is obviously harder to get information on but it imports large amounts of food from China.
    - SideburnsOfDoom 3mo ago
      North Korea has an official ideology of "Juche", and "The goal of Juche is to establish a self-reliant state" (1) It may not be like that in practice. But nevertheless, self-reliance is in their stated goals, and North Korea is one of the least "open" states in the world. I think you can make the case that they "try to be self-sufficient". They do try. As for Israel, eh, it depends. They certainly don't rely on neighbouring countries. 1) https://en.wikipedia.org/wiki/Juche#Core_principles https://en.wikipedia.org/wiki/Juche#Core_principles
      - neaden 3mo ago
        Sure North Korea tries, but they don't succeed so it's not really helpful as an example of a self sufficient society to base a space colony off of. As for Israel yeah, they mostly don't import food from their neighbors (most of whom also import the majority of their food calories) but I don't see what that has to do with anything, as I said they import 80% of their calories which is certainly not tenable for a space colony to do.
  - giantrobot 3mo ago
    Both North Korea and Israel are notable (compared to space) for their dense oxygen rich atmospheres, accessible large reservoirs of water, access to solvents/lubricants, and a generally "shirt sleeves" environment for workers. Asteroids, the Moon, and deep space don't really have these things. So you're not just bootstrapping an industrial facility at those locations but all the basic infrastructure that industry requires to exist. With space manufacturing the first widget out of a factory costs trillions of dollars. There's also few if any raw materials that are far more abundant in space than here on Earth (at orders of magnitude smaller cost).
chopin 3mo ago
Honestly, I always assumed that consensus was that replication is the hardest part. I believe we have almost none of the technologies required for that. Whenever I read of von Neumann probes I always thought "How can that even made possible?".
in-silico 3mo ago
One "solution" to these problems is to have the probes land on planets instead of asteroids, and build the necessary infrastructure there.
- jpitz 3mo ago
  That solves many of those problems, although it rather introduces a big gravity well to escape from when replication is complete.
  - mNovak 3mo ago
    Though, by the time we've replicated a complete industrial hinterland (up to and including a semiconductor supply chain) which the author describes, it seems like generating fuel and engines wouldn't be impossible. Also to the authors last point (extremely long time scales causing degradation), it seems like we'd want high thrust capabilities regardless. i.e. maybe a small gravity well doesn't gain us anything, since we'd need big engines to get up to speed anyway.
voidmain 3mo ago
There is no doubt that compressing a whole industrial supply network into a little probe is incredibly hard. But I can't see microgravity specifically as a huge challenge. If you can get a probe to another star system, you can probably figure out how to spin it.
- mNovak 3mo ago
  I suppose it depends if you're assuming the probe is a complete factory, just taking in regolith and spitting out new probes, vs if the probe deploys and builds up the factory on the surface of an asteroid. In the latter case spinning doesn't get you far.
credit_guy 3mo ago
> Shrinking that into a 500 kg seed — or even Freitas’ original 100-ton seed — is not an engineering detail. It may be the entire problem. How many AI tells can you count there? But honestly (see what I did there?) the AI slop is reasonably cleaned up in this piece. However, the essence of the argument has two deep flaws. One is that the time to complete an interstellar voyage is extremely long and you need some exergy, yada, yada, yada. We could start with sending self-replicating probes to the asteroid belt. There is zero chance that we'll attempt to send self-replicating probes to a different star system before we send them inside our own solar system. And the second error is this: > Bootstrapping this loop [...] is a chicken-and-egg problem that no study I am aware of has worked through at the level of actual process flowsheets. The fact that the current technology is not adequate, and nobody even attempted to solve such a problem is a weak argument. Three hundred years ago nobody had "worked through the process flowsheets" of making an injection molding machine, or a 3D printer, or a power drill, yet they are all available now.
- JohnMakin 3mo ago
  300 years ago people also believed alchemy was a serious field of study
  - credit_guy 3mo ago
    That is true. What should we conclude from this statement?
    - JohnMakin 3mo ago
      That you shouldn’t assume just because in the past ideas have existed that became reality, that all current ideas are feasible or possible?
      - credit_guy 3mo ago
        I didn’t assume that. The author makes the opposite assumption: that because nobody has ever proposed a path to technological feasibility, that thing will forever be technologically unfeasible. I simply find this argument to be very weak.
bryanlarsen 3mo ago
If an elderly but distinguished scientist says that something is possible, he is almost certainly right; but if he says that it is impossible, he is very probably wrong. - Arthur C Clarke
- aaron695 3mo ago
  [dead]
- neaden 3mo ago
  OK, so elderly distinguished scientists say it is impossible for me to travel FTL by spinning in a circle with my eyes closed while on acid, guess we should start investing research dollars into that.
seiferteric 3mo ago
Wouldn't a counter this argument be biological systems? These are reasonable points as long as we are talking about current methods, but I assume if we were to get to the point of self replicating probes it would be done by something like nanotechnology, synthetic biology like systems.
- artemonster 3mo ago
  We are selfreplicating bots - can eat anything, self healing minor damage, very agile, autonomous. When we stop growing numbers the harvest will begin
  - seiferteric 3mo ago
    thats what i meant.
    - golem14 3mo ago
      ... but traveling for months, years, decades and millennia in space away from earth has proven difficult so far. Even astronauts in space for a year had significant changes afterwards.
  - pjio 3mo ago
    > When we stop growing numbers the harvest will begin I like this part. It gives me chills.
- andrewflnr 3mo ago
  Somewhat famously with life, you aren't necessarily replicating the same thing at the end as you are at the beginning, which is an awkward property for an engineered system.
  - Windchaser 3mo ago
    So that adds some extra "benefits" (mutation and natural selection improves the probes over time) along with some extra difficulties - how do you keep the self-reproducing probes "on-task" from one generation to the next? How do you instill "explore and report home" as an innate goal to a mutating system?
davedx 3mo ago
I did some research on this in the context of self-replicating PV panel construction. I arrived at similar conclusions: mining (ore extraction and refining) was the hardest part. Our current methods involve all involve some kind of high energy system: - crushing - breaking down with powerful solutions - blasting And a self-replicating probe will (initially at least) be a low energy system. I eventually decided that the pathway with the most likelihood of success would be some kind of very slow crushing/grinding machine that can break down ore into separable components, but then you get into a kind of Darwinist explosive combinatorics research rabbit hole: which crusher/grinder, what kind of machine, how to make something that works on different ore types, what mechanical pressure is better? Conceptualizing something that can sinter and assemble PV cells was pretty easy, there are broad families of chemistries that work and they mainly differ on input temperatures and output efficiencies. Fairly tractable. But mineral extraction... yeesh, it's extremely difficult. FWIW on the original article: I think the jump from "insulating wires" to "semiconductor fabs" was kind of obtuse. You don't necessarily need Turing complete PCBs or microchips for most (any?) of this.
andrewflnr 3mo ago
The thermodynamic argument seems much more important to the Fermi Paradox than any difficulties in refining material, but I don't think I understand it.
- abecedarius 3mo ago
  If physics were to forbid closure at small scale, how could life begin? And how does a micron-scale autotroph reproduce?
marcosdumay 3mo ago
Yes, we don't know how to make a half-ton replicating probe right now. No, none of the arguments on the article have any implication on the possibility of such a probe. None at all. There's something to look into at the durability argument. The article has no usable information on it, and it's probably not a showstopper. But again, the only thing on the article is that yes, we don't know how to make one such probe right now.
- simiones 3mo ago
  I hate this assumption that many sci-fi enthusiasts seem to make, that as long as something is not ruled out by currently known physics rules, it doesn't matter that we have no idea how it could be built, there will be some way in some plausible future. When we see currently insurmountable problems in creating a piece of technology, it's absolutely possible that we'll never be able to build it. Even if it is theoretically constructible, there is no reason to believe that the way to build it would be found before, say, the sun runs out of hydrogen.
  - marcosdumay 3mo ago
    It's absolutely possible that we'll never be able to build it. There's absolutely no evidence of that on the article.
    - bunderbunder 3mo ago
      Of course not. That isn’t what the article was trying to say. The thesis was, “I would like to suggest that the hardest part is the one that gets a single sentence: ‘mines local material and builds a copy.’” And so naturally the points in the article are only trying to support that point. The closest we get to what this thread is talking about is the concluding remark on the Fermi paradox. Which doesn’t rest on the idea that it’s a practical impossibility; just on the suggestion that it may be hard enough that we can’t just assume civilizations that are in principle capable of building them are likely to actually do it.
    - ordu 3mo ago
PaulHoule 3mo ago
CC asteroids have hydrogen, oxygen and carbon and with chemistry a bit like https://www.dakotagas.com/ https://www.dakotagas.com/ that is, CC asteroid contain “coal” more or less. I don’t see a problem with drawing flowsheets for metals like iron, stones like silicon and even BTX chemicals to produce plastics. You cycle syngas and treat resulting H2O and CO2 as precious. Now I was not thinking of a 500kg “seed” but a factory factory that is packed up in 100 ton loads that builds a sunshade factory by a process like building a ship inside a bottle except inside out. I did worry about how you handle devolatization at the beginning, like it is precious and maybe even dangerous and it would be real nice to do it all at the beginning but you don’t have the storage tank factory online (thought a lot about storage tanks!) The plan was to do all this in our solar system to sail sunshades to the Earth-Sun L1 point, the big questions I had was “how do you fix problems when it is hands-off that far away?” (physical twin in cislunar space for one thing!) vs “do you send people who you have to keep alive? can you bring them back? do they turn into Zeons?” I have thought about the Drexler problem when it comes to Mars colonization and can’t think of a better answer than a synthetic biology platform based on bacteria and possibly yeast which can do versatile if not efficient chemical synthesis from syngas or photosynthesis. You still need flow chemistry, 3-d printing and some more methodologies but the project of “advanced manufacturing” that would enable a small settlement to achieve autakry seems achievable to me and would be essential for interplanetary colonization and helpful in case of forced degrowth.
- cindyllm 3mo ago
  [dead]
m3kw9 3mo ago
It’s true that current tech can’t do it and he has said it but it doesn’t mean new tech can’t do it. He is assuming other civilizations cannot do it and also assuming probes will be easily detected therefore there are no probes
M95D 3mo ago
> 2. Is there a credible inorganic-only pathway for electrical insulation and semiconductor packaging? What about glass, SiO2?
dmurvihill 3mo ago
[dead]
jonathanlydall 3mo ago
Well, if this and other problems are ever solved towards self-replicating probes, we must just make sure not to over-prioritize replication like the Slylandro: https://wiki.starcontrol.com/index.php/Probe https://wiki.starcontrol.com/index.php/Probe
bilsbie 3mo ago
I find the confusion confusing. Meaning isn’t it obvious it would take an entire civilization and all of its technology to create functional space craft, computers, and mining robots? I don’t see how anyone would expect some kind of self contained probe to be able to do all of that.
SequoiaHope 3mo ago
Oh wow the concept of Vitamins, which I learned about from the Reprap Project, must have come from that 1980 NASA study! https://reprap.org/wiki/Category:Vitamin https://reprap.org/wiki/Category:Vitamin
chrisshroba 3mo ago
This article contains 19 em-dashes, as well as the following direct quotes: Not X, but dramatic Y: - "But the missing few percent are not marginal; they are precisely the hardest items" - "is not an engineering detail. It may be the entire problem. - "the galaxy may be quiet not because nobody tried, but because replication is harder than arithmetic suggests." as well as at least two other longer "not X, it's Y" type phrases. Also, melodramatic phrasing like "Replication must outrun degradation — and degradation never sleeps." Yes, someone could have written these manually, but these particular patterns are the things I notice most commonly in LLM outputs that I don't see in known-human writing.
- therobots927 3mo ago
  Thanks. You saved me some time.
torginus 3mo ago
This whole story is so nonsensical - we can't make self replicating probes because the materials are very hard to extract - extract from what? Perhaps if that is the case, it's because you have to get the metal from that mineral-rich rock that's like 0.1% of said metal by content. Why not build probes from the rest? Common atoms like carbon etc.
- crewindream 3mo ago
  1. Carbon quality would need to be ensured somehow - sounds like extraction/refinement still necessary 2. Carbon seems to be brittle.
- lioeters 3mo ago
  I imagine the extreme physical constraints will force us to explore alternative and unconventional forms of machines and computers, built from different materials available. For example, molecular or microscopic scale of self-replicating machines might be "easier" to build than what we typically think of as machines.
deepsun 3mo ago
> Is there a credible inorganic-only pathway for electrical insulation Well, there is -- distance. Also, the regolith is a good electrical insulator. Also, basic organic compounds are plentiful in space.

158 points by EA-3167 3mo ago

zeryx 3mo ago

I studied material science in school specifically to try and address his concerns. Unfortunately they are all quite valid - the hard part isn't manufacturing, extruding, printing. Those are actually all quite reasonable (albeit not super space or weight efficient). The hard part is refining and ore enrichment, and most techniques that could possibly work in microgravity are almost impossible to test on earth. You would certainly need vitamins for electronics components for a time. Even much older computer chip architectures (1990s level) still require the clean room and 20-30 stages of prep. I believe an orbital chip fab is not only possible but, kind of ideal? Keeping it clean would be within reach - and it's mostly if not entirely an autonomous process from silicon monocrystal to assembled part today. We're along way from self replicating probes. But I would argue were quite capable of autonomous mining, manufacturing and material transport - assuming we can figure out how to refine effectively. If someone wants a cool PhD project and ship an experiment to the ISS, I would argue an ionic or plasma based refining technique designed for micro gravity could be very interesting and very useful

Animats 3mo ago
> Every terrestrial concentration process relies on things an asteroid lacks: gravity-driven sedimentation, water-based flotation, density separation in fluids, atmospheric combustion. That's a good point. Most bulk industrial processes won't work in zero G. This limits asteroid mining. Breaking off pieces of rock and accelerating them to somewhere, maybe. Building a big wheel and spinning it up to get some gravity, maybe. Materials processing in open space, not so much. The "seed" to start up an industrial economy might be the size of the industrial base of, say, Israel or North Korea, both of which try to be self-sufficient. We get to find out when someone tries to do something self-sustaining on Luna or Mars.
- neaden 3mo ago
  "Israel or North Korea, both of which try to be self-sufficient" - Neither of them do any such thing though. From a quick search Israel imports about 80% of their calories though they also export some food they are heavily reliant on imported grains and meat. North Korea is obviously harder to get information on but it imports large amounts of food from China.
  - SideburnsOfDoom 3mo ago
    North Korea has an official ideology of "Juche", and "The goal of Juche is to establish a self-reliant state" (1) It may not be like that in practice. But nevertheless, self-reliance is in their stated goals, and North Korea is one of the least "open" states in the world. I think you can make the case that they "try to be self-sufficient". They do try. As for Israel, eh, it depends. They certainly don't rely on neighbouring countries. 1) https://en.wikipedia.org/wiki/Juche#Core_principles https://en.wikipedia.org/wiki/Juche#Core_principles
    - neaden 3mo ago
      Sure North Korea tries, but they don't succeed so it's not really helpful as an example of a self sufficient society to base a space colony off of. As for Israel yeah, they mostly don't import food from their neighbors (most of whom also import the majority of their food calories) but I don't see what that has to do with anything, as I said they import 80% of their calories which is certainly not tenable for a space colony to do.
- giantrobot 3mo ago
  Both North Korea and Israel are notable (compared to space) for their dense oxygen rich atmospheres, accessible large reservoirs of water, access to solvents/lubricants, and a generally "shirt sleeves" environment for workers. Asteroids, the Moon, and deep space don't really have these things. So you're not just bootstrapping an industrial facility at those locations but all the basic infrastructure that industry requires to exist. With space manufacturing the first widget out of a factory costs trillions of dollars. There's also few if any raw materials that are far more abundant in space than here on Earth (at orders of magnitude smaller cost).

chopin 3mo ago

Honestly, I always assumed that consensus was that replication is the hardest part. I believe we have almost none of the technologies required for that. Whenever I read of von Neumann probes I always thought "How can that even made possible?".

in-silico 3mo ago

One "solution" to these problems is to have the probes land on planets instead of asteroids, and build the necessary infrastructure there.

jpitz 3mo ago
That solves many of those problems, although it rather introduces a big gravity well to escape from when replication is complete.
- mNovak 3mo ago
  Though, by the time we've replicated a complete industrial hinterland (up to and including a semiconductor supply chain) which the author describes, it seems like generating fuel and engines wouldn't be impossible. Also to the authors last point (extremely long time scales causing degradation), it seems like we'd want high thrust capabilities regardless. i.e. maybe a small gravity well doesn't gain us anything, since we'd need big engines to get up to speed anyway.

voidmain 3mo ago

There is no doubt that compressing a whole industrial supply network into a little probe is incredibly hard. But I can't see microgravity specifically as a huge challenge. If you can get a probe to another star system, you can probably figure out how to spin it.

mNovak 3mo ago
I suppose it depends if you're assuming the probe is a complete factory, just taking in regolith and spitting out new probes, vs if the probe deploys and builds up the factory on the surface of an asteroid. In the latter case spinning doesn't get you far.

credit_guy 3mo ago

> Shrinking that into a 500 kg seed — or even Freitas’ original 100-ton seed — is not an engineering detail. It may be the entire problem. How many AI tells can you count there? But honestly (see what I did there?) the AI slop is reasonably cleaned up in this piece. However, the essence of the argument has two deep flaws. One is that the time to complete an interstellar voyage is extremely long and you need some exergy, yada, yada, yada. We could start with sending self-replicating probes to the asteroid belt. There is zero chance that we'll attempt to send self-replicating probes to a different star system before we send them inside our own solar system. And the second error is this: > Bootstrapping this loop [...] is a chicken-and-egg problem that no study I am aware of has worked through at the level of actual process flowsheets. The fact that the current technology is not adequate, and nobody even attempted to solve such a problem is a weak argument. Three hundred years ago nobody had "worked through the process flowsheets" of making an injection molding machine, or a 3D printer, or a power drill, yet they are all available now.

JohnMakin 3mo ago
300 years ago people also believed alchemy was a serious field of study
- credit_guy 3mo ago
  That is true. What should we conclude from this statement?
  - JohnMakin 3mo ago
    That you shouldn’t assume just because in the past ideas have existed that became reality, that all current ideas are feasible or possible?
    - credit_guy 3mo ago
      I didn’t assume that. The author makes the opposite assumption: that because nobody has ever proposed a path to technological feasibility, that thing will forever be technologically unfeasible. I simply find this argument to be very weak.

bryanlarsen 3mo ago

If an elderly but distinguished scientist says that something is possible, he is almost certainly right; but if he says that it is impossible, he is very probably wrong. - Arthur C Clarke

aaron695 3mo ago
[dead]
neaden 3mo ago
OK, so elderly distinguished scientists say it is impossible for me to travel FTL by spinning in a circle with my eyes closed while on acid, guess we should start investing research dollars into that.

seiferteric 3mo ago

Wouldn't a counter this argument be biological systems? These are reasonable points as long as we are talking about current methods, but I assume if we were to get to the point of self replicating probes it would be done by something like nanotechnology, synthetic biology like systems.

artemonster 3mo ago
We are selfreplicating bots - can eat anything, self healing minor damage, very agile, autonomous. When we stop growing numbers the harvest will begin
- seiferteric 3mo ago
  thats what i meant.
  - golem14 3mo ago
    ... but traveling for months, years, decades and millennia in space away from earth has proven difficult so far. Even astronauts in space for a year had significant changes afterwards.
- pjio 3mo ago
  > When we stop growing numbers the harvest will begin I like this part. It gives me chills.
andrewflnr 3mo ago
Somewhat famously with life, you aren't necessarily replicating the same thing at the end as you are at the beginning, which is an awkward property for an engineered system.
- Windchaser 3mo ago
  So that adds some extra "benefits" (mutation and natural selection improves the probes over time) along with some extra difficulties - how do you keep the self-reproducing probes "on-task" from one generation to the next? How do you instill "explore and report home" as an innate goal to a mutating system?

davedx 3mo ago

I did some research on this in the context of self-replicating PV panel construction. I arrived at similar conclusions: mining (ore extraction and refining) was the hardest part. Our current methods involve all involve some kind of high energy system: - crushing - breaking down with powerful solutions - blasting And a self-replicating probe will (initially at least) be a low energy system. I eventually decided that the pathway with the most likelihood of success would be some kind of very slow crushing/grinding machine that can break down ore into separable components, but then you get into a kind of Darwinist explosive combinatorics research rabbit hole: which crusher/grinder, what kind of machine, how to make something that works on different ore types, what mechanical pressure is better? Conceptualizing something that can sinter and assemble PV cells was pretty easy, there are broad families of chemistries that work and they mainly differ on input temperatures and output efficiencies. Fairly tractable. But mineral extraction... yeesh, it's extremely difficult. FWIW on the original article: I think the jump from "insulating wires" to "semiconductor fabs" was kind of obtuse. You don't necessarily need Turing complete PCBs or microchips for most (any?) of this.

andrewflnr 3mo ago

The thermodynamic argument seems much more important to the Fermi Paradox than any difficulties in refining material, but I don't think I understand it.

abecedarius 3mo ago
If physics were to forbid closure at small scale, how could life begin? And how does a micron-scale autotroph reproduce?

marcosdumay 3mo ago

Yes, we don't know how to make a half-ton replicating probe right now. No, none of the arguments on the article have any implication on the possibility of such a probe. None at all. There's something to look into at the durability argument. The article has no usable information on it, and it's probably not a showstopper. But again, the only thing on the article is that yes, we don't know how to make one such probe right now.

simiones 3mo ago
I hate this assumption that many sci-fi enthusiasts seem to make, that as long as something is not ruled out by currently known physics rules, it doesn't matter that we have no idea how it could be built, there will be some way in some plausible future. When we see currently insurmountable problems in creating a piece of technology, it's absolutely possible that we'll never be able to build it. Even if it is theoretically constructible, there is no reason to believe that the way to build it would be found before, say, the sun runs out of hydrogen.
- marcosdumay 3mo ago
  It's absolutely possible that we'll never be able to build it. There's absolutely no evidence of that on the article.
  - bunderbunder 3mo ago
    Of course not. That isn’t what the article was trying to say. The thesis was, “I would like to suggest that the hardest part is the one that gets a single sentence: ‘mines local material and builds a copy.’” And so naturally the points in the article are only trying to support that point. The closest we get to what this thread is talking about is the concluding remark on the Fermi paradox. Which doesn’t rest on the idea that it’s a practical impossibility; just on the suggestion that it may be hard enough that we can’t just assume civilizations that are in principle capable of building them are likely to actually do it.
  - ordu 3mo ago

PaulHoule 3mo ago

CC asteroids have hydrogen, oxygen and carbon and with chemistry a bit like https://www.dakotagas.com/ https://www.dakotagas.com/ that is, CC asteroid contain “coal” more or less. I don’t see a problem with drawing flowsheets for metals like iron, stones like silicon and even BTX chemicals to produce plastics. You cycle syngas and treat resulting H2O and CO2 as precious. Now I was not thinking of a 500kg “seed” but a factory factory that is packed up in 100 ton loads that builds a sunshade factory by a process like building a ship inside a bottle except inside out. I did worry about how you handle devolatization at the beginning, like it is precious and maybe even dangerous and it would be real nice to do it all at the beginning but you don’t have the storage tank factory online (thought a lot about storage tanks!) The plan was to do all this in our solar system to sail sunshades to the Earth-Sun L1 point, the big questions I had was “how do you fix problems when it is hands-off that far away?” (physical twin in cislunar space for one thing!) vs “do you send people who you have to keep alive? can you bring them back? do they turn into Zeons?” I have thought about the Drexler problem when it comes to Mars colonization and can’t think of a better answer than a synthetic biology platform based on bacteria and possibly yeast which can do versatile if not efficient chemical synthesis from syngas or photosynthesis. You still need flow chemistry, 3-d printing and some more methodologies but the project of “advanced manufacturing” that would enable a small settlement to achieve autakry seems achievable to me and would be essential for interplanetary colonization and helpful in case of forced degrowth.

cindyllm 3mo ago
[dead]

m3kw9 3mo ago

It’s true that current tech can’t do it and he has said it but it doesn’t mean new tech can’t do it. He is assuming other civilizations cannot do it and also assuming probes will be easily detected therefore there are no probes

M95D 3mo ago

> 2. Is there a credible inorganic-only pathway for electrical insulation and semiconductor packaging? What about glass, SiO2?

dmurvihill 3mo ago

[dead]

jonathanlydall 3mo ago

Well, if this and other problems are ever solved towards self-replicating probes, we must just make sure not to over-prioritize replication like the Slylandro: https://wiki.starcontrol.com/index.php/Probe https://wiki.starcontrol.com/index.php/Probe

bilsbie 3mo ago

I find the confusion confusing. Meaning isn’t it obvious it would take an entire civilization and all of its technology to create functional space craft, computers, and mining robots? I don’t see how anyone would expect some kind of self contained probe to be able to do all of that.

SequoiaHope 3mo ago

Oh wow the concept of Vitamins, which I learned about from the Reprap Project, must have come from that 1980 NASA study! https://reprap.org/wiki/Category:Vitamin https://reprap.org/wiki/Category:Vitamin

chrisshroba 3mo ago

This article contains 19 em-dashes, as well as the following direct quotes: Not X, but dramatic Y: - "But the missing few percent are not marginal; they are precisely the hardest items" - "is not an engineering detail. It may be the entire problem. - "the galaxy may be quiet not because nobody tried, but because replication is harder than arithmetic suggests." as well as at least two other longer "not X, it's Y" type phrases. Also, melodramatic phrasing like "Replication must outrun degradation — and degradation never sleeps." Yes, someone could have written these manually, but these particular patterns are the things I notice most commonly in LLM outputs that I don't see in known-human writing.

therobots927 3mo ago
Thanks. You saved me some time.

torginus 3mo ago

This whole story is so nonsensical - we can't make self replicating probes because the materials are very hard to extract - extract from what? Perhaps if that is the case, it's because you have to get the metal from that mineral-rich rock that's like 0.1% of said metal by content. Why not build probes from the rest? Common atoms like carbon etc.

crewindream 3mo ago
1. Carbon quality would need to be ensured somehow - sounds like extraction/refinement still necessary 2. Carbon seems to be brittle.
lioeters 3mo ago
I imagine the extreme physical constraints will force us to explore alternative and unconventional forms of machines and computers, built from different materials available. For example, molecular or microscopic scale of self-replicating machines might be "easier" to build than what we typically think of as machines.

deepsun 3mo ago

> Is there a credible inorganic-only pathway for electrical insulation Well, there is -- distance. Also, the regolith is a good electrical insulator. Also, basic organic compounds are plentiful in space.