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.
I would also think that self-replicating probes would work more like living things. He seems to be imagining that we make probes like modern machines, and then find ways to let them build themselves. But nature found much easier solutions.
The self-replication assumes also that there is enough energy stored in each planet (or coming from a Sun) to do the work... That is pretty much unlikely.
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.
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.
Why would biological systems be a counterargument? Smelting metals and sustaining life both require an enormous amount of water and about ~1ATM of atmosphere, as far as we know, and there's no plausible known mechanism for sidestepping this requirement. So "magical synthetic biology that can self-replicate in space" is actually a worse solution to the problem than "magical metallurgy that can be done in space" since humans at least have smelted metals, but we've never built synthetic forms of life. (Not counting CRISPR)
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.
> 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.
Biological systems require extremely specific environments that aren't space.
Yeah, you can self-replicate (well, not exactly self-replicate), but just think of all the "infrastructure" you need to do that: massive volumes of air and water, all kinds of weird chemicals not found in minerals, a whole biosphere of other stuff, a literal star, etc. And none of that infrastructure is really space-worthy on any reasonable scale for a probe.
If you broke it all down, I bet you'd need a mass/volume at least as big as a more technological probe. And you still need the technological infrastructure to build a vessel to hold it all together.
Yes, I was wondering why the focus on metals. (Admittedly they might be needed in trace amounts for catalysis, or convenient for conductors, etc., or for structural material if you're on a carbon-poor asteroid. Most metals are worse than carbon for the latter if you have reasonably high tech.)
Biology ignored some of the most abundant elements because they can't be worked with under the constrained temperature and pressure conditions where biological systems operate. Biology barely uses any silicon, even though it is the second-most common element in the biosphere. Biology does not use aluminum, the third-most common element, at all. Biology does use iron but cannot reduce it to the pure metal. In fact, biological systems produce no metals. Structurally, biology relies on weak minerals like calcium carbonate and calcium phosphate, rather than much stronger ones like quartz and alumina, because of the difficulty of biochemical processing.
This isn't insurmountable for a probe. Biology can get stuck in local optima. Humans have the Periodic Table and quantum mechanics. But it means we are on untrodden ground. Refining titanium, today, uses a massive molybdenum-lined reactor operating at 1600 C (2900 F). The alternative processes (FFC and Chinuka) use liquid calcium chloride, mp 773 C. The square-cube law points to enormous energy losses trying to scale these processes down. And that's just one element.
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
> 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.
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.
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.
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.
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.
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.
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.
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
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?".
> 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.
All of those read like AI, especially considering that the subsections aren't consistent. Some are numbers, some are not, some are framings some are problem juxtapositions.
EM dashes everywhere, AI tells in subheadings, "It's not X it's Y" all over the text of the body. This is clearly AI writen.
Notice also the article has two by lines. At the top it's "by Paul Gilster" at the top of the text it's "by Peter Marinko"
Also note that the "metallugrist" they're interviewing that they claim "his current work explores the thermodynamics of technological civilizations" at Uppsala University, but the university's page for him says he's only involved in Animal Research Ethics Committee
It’s a bit silly to be so sensitive to “AI tells” in phrasing. If you go look for them in original human writing, you are guaranteed to find them—just like the AI training did! That’s how they became “tells” in the first place.
I find this line of reason to be incredibly irritating. So anything written above the level of "see Spot run" now must be AI slop? The author's piece is written well and reads easily.
As a long-time user of nonrestrictive elements in sentences, I bristle at the idea that only AI is capable of writing sentences containing brief asides -- the things between the em dashes -- now.
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.
I would also think that self-replicating probes would work more like living things. He seems to be imagining that we make probes like modern machines, and then find ways to let them build themselves. But nature found much easier solutions.
The self-replication assumes also that there is enough energy stored in each planet (or coming from a Sun) to do the work... That is pretty much unlikely.
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.
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.
Why would biological systems be a counterargument? Smelting metals and sustaining life both require an enormous amount of water and about ~1ATM of atmosphere, as far as we know, and there's no plausible known mechanism for sidestepping this requirement. So "magical synthetic biology that can self-replicate in space" is actually a worse solution to the problem than "magical metallurgy that can be done in space" since humans at least have smelted metals, but we've never built synthetic forms of life. (Not counting CRISPR)
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.
> 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.
Biological systems require extremely specific environments that aren't space.
Yeah, you can self-replicate (well, not exactly self-replicate), but just think of all the "infrastructure" you need to do that: massive volumes of air and water, all kinds of weird chemicals not found in minerals, a whole biosphere of other stuff, a literal star, etc. And none of that infrastructure is really space-worthy on any reasonable scale for a probe.
If you broke it all down, I bet you'd need a mass/volume at least as big as a more technological probe. And you still need the technological infrastructure to build a vessel to hold it all together.
Yes, I was wondering why the focus on metals. (Admittedly they might be needed in trace amounts for catalysis, or convenient for conductors, etc., or for structural material if you're on a carbon-poor asteroid. Most metals are worse than carbon for the latter if you have reasonably high tech.)
Biology ignored some of the most abundant elements because they can't be worked with under the constrained temperature and pressure conditions where biological systems operate. Biology barely uses any silicon, even though it is the second-most common element in the biosphere. Biology does not use aluminum, the third-most common element, at all. Biology does use iron but cannot reduce it to the pure metal. In fact, biological systems produce no metals. Structurally, biology relies on weak minerals like calcium carbonate and calcium phosphate, rather than much stronger ones like quartz and alumina, because of the difficulty of biochemical processing.
This isn't insurmountable for a probe. Biology can get stuck in local optima. Humans have the Periodic Table and quantum mechanics. But it means we are on untrodden ground. Refining titanium, today, uses a massive molybdenum-lined reactor operating at 1600 C (2900 F). The alternative processes (FFC and Chinuka) use liquid calcium chloride, mp 773 C. The square-cube law points to enormous energy losses trying to scale these processes down. And that's just one element.
We are selfreplicating bots - can eat anything, self healing minor damage, very agile, autonomous. When we stop growing numbers the harvest will begin
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
> 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.
CC asteroids have hydrogen, oxygen and carbon and with chemistry a bit like
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.
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
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.
> 2. Is there a credible inorganic-only pathway for electrical insulation and semiconductor packaging?
What about glass, SiO2?
One "solution" to these problems is to have the probes land on planets instead of asteroids, and build the necessary infrastructure there.
That solves many of those problems, although it rather introduces a big gravity well to escape from when replication is complete.
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.
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.
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.
If physics were to forbid closure at small scale, how could life begin? And how does a micron-scale autotroph reproduce?
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
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?".
> 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.
The subheadings are all full of AI tells.
> The closure problem, honestly accounted
> A thermodynamic framing
All of those read like AI, especially considering that the subsections aren't consistent. Some are numbers, some are not, some are framings some are problem juxtapositions.
EM dashes everywhere, AI tells in subheadings, "It's not X it's Y" all over the text of the body. This is clearly AI writen.
Notice also the article has two by lines. At the top it's "by Paul Gilster" at the top of the text it's "by Peter Marinko"
Also note that the "metallugrist" they're interviewing that they claim "his current work explores the thermodynamics of technological civilizations" at Uppsala University, but the university's page for him says he's only involved in Animal Research Ethics Committee
It’s a bit silly to be so sensitive to “AI tells” in phrasing. If you go look for them in original human writing, you are guaranteed to find them—just like the AI training did! That’s how they became “tells” in the first place.
300 years ago people also believed alchemy was a serious field of study
I find this line of reason to be incredibly irritating. So anything written above the level of "see Spot run" now must be AI slop? The author's piece is written well and reads easily. As a long-time user of nonrestrictive elements in sentences, I bristle at the idea that only AI is capable of writing sentences containing brief asides -- the things between the em dashes -- now.