So, I understand that a common way to explore the universe and colonise worlds is through Von Neumann Probes. Self-replicating and efficient... except for the fact that, as far as I have seen in multiple discussions, including here, making an actual Von Neumann Probe is as good as impossible due to the complexity involved in both the computing substrates and the materials.

However, I might have an idea, though there is one bit missing.

According to Wikipedia, these are the needed parts of a Von Neumann Probe:

  • Probe: which would contain the actual probing instruments & goal-directed AI to guide the construct.
  • Life-support systems: mechanisms to repair and maintain the construct.
  • Factory: mechanisms to harvest resources & replicate itself.
  • Memory banks: store programs for all its components & information gained by the probe.
  • Engine: motor to move the probe.

For the Memory Banks, my world is one where Computronium already exists, small and efficient, in the form of Rydberg Atoms. It is already confirmed in the real world that Rydberg Atoms make a good form of Computronium.

Now, for the Factory, I imagine two parts: The same robotic arms used in that for Utility Fog for deconstructing and making, and also the microchip-sized electron particle accelerators to make more Rydberg Atoms. This happens as Rydberg Atoms are said to be made from electron impact excitation.

Lastly, for the motors, there are molecular-sized motors that can do this job to move the limbs of the probe.

I ditched the idea of them being self-propelled and interstellar, and prefer that they be restricted to only planets, being sent there via carriers.

This leaves behind three issues: The material the Von Neumann Probes should use to build another, the energy source to power it, and the basic commands.

Let us begin with the materials. It can be more than one, for versatility, but all must be common and be able to be used to make the given parts (except for the Computronium processor, we already settled that).

The problem for energy and commands will be in another post.

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    $\begingroup$ "Making an actual Von Neumann Probe is as good as impossible": hmmm. We have almost 8 billion von Neumann probes on Earth already. They are called humans and are made mostly of water, proteins, fatty acids and hydroxyapatite. They even have a built-in mechanism to make new ones, and have acquired fully functional procedures to transmit the required programming. $\endgroup$
    – AlexP
    Jun 24, 2020 at 12:17
  • $\begingroup$ The use of jargon makes it look like you want a hard science answer. But at the same time you already have these handwavey concepts like "microscopic particle accelerators". So I have no idea what sort of answer you are looking for. $\endgroup$
    – Daron
    Jun 24, 2020 at 12:39
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    $\begingroup$ But "I want self-replicating machines. What should they use for raw materials and energy?" is probably the sort of question with loads of answers already on the site. You should search for those answers and if they are not sufficient, use them to inform a much more specific problem you want help with. $\endgroup$
    – Daron
    Jun 24, 2020 at 12:48
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    $\begingroup$ The Bobiverse books address this pretty well. With advance tech, just 3d print everything at an atomic level rather than trying to use nanites and such. the materials needed are all already on the periodic table. $\endgroup$
    – Paul TIKI
    Jun 24, 2020 at 12:57
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    $\begingroup$ "It is already confirmed in the real world that Rydberg Atoms make a good form of Computronium." Citation needed! Nobody has made real-world computronium. Rydberg atoms have been used to make a 2-qbit quantum computer, but that's a very different thing from computronium. $\endgroup$ Jun 28, 2020 at 14:58

1 Answer 1


This answer doesn't so much as answer your question as point out that your question is so ambiguous that it seems trivial to answer.

Assertion: You have an automated, mobile factory capable of converting available raw materials into necessary repair and replication components and energy. Your probe has the technology to use electron impact excitation as a form of matter manipulation, so it obviously has the lower technologies such as basic metallurgy (smelting, alloying, chemical processing, etc.) or some high-tech version of them. It obviously also has the ability to store raw materials until all the materials necessary for repair, replication, and energy are gathered. What materials are then needed?

Below, please find a copy of the Periodic Table of Elements.

enter image description here

You'll need most of them, which will then be combined and manipulated to create more complex structures as required by your probe. But that's OK, because your probes are going to planets where most (indeed all) of these elements can be found.

I know this was really sarcastic, but honestly, it's the only answer I can think of that makes any sense when compared to your question. If this post doesn't completely answer your question, please spend less time with irrelevant background and more time defining exactly what you want, any limitations or restrictions we must be aware of, and explaining how you will judge a best answer. Thanks.

BTW, I read a book as a much younger man and for the life of me I can't remember its title, but it used the concept of Von Neumann probes in a planetary context. Their purpose was to gather raw materials, using those raw materials to replicate themselves, and then return to the colony site. The probes were sent in long before colonists arrived so they had a plentiful collection of resources waiting for them. Basically, the were a form of automated mining with a really high geek factor. I wonder if I still have that book in a box somewhere?

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    $\begingroup$ You may be able to track down that book over on sci-fi.se. $\endgroup$ Jul 22, 2020 at 1:18

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