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 pa…
A metallurgist's doubts about self-replicating probes
41–50 of 103 posts
Re: A metallurgist's doubts about self-replicating probes
#42Earlier quoted context omitted.
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.
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?
Re: A metallurgist's doubts about self-replicating probes
#43Wouldn'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.
Re: A metallurgist's doubts about self-replicating probes
#44> 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 exer…
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.
This reads as heavily LLM generated/edited to me.
Re: A metallurgist's doubts about self-replicating probes
#45Re: A metallurgist's doubts about self-replicating probes
#46Yes, 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 ri…
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 theoreti…
Re: A metallurgist's doubts about self-replicating probes
#47> 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 exer…
Re: A metallurgist's doubts about self-replicating probes
#48Yes, 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 ri…
Re: A metallurgist's doubts about self-replicating probes
#49What about glass, SiO2?
Re: A metallurgist's doubts about self-replicating probes
#50Wouldn'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.
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.