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Comment by gene-h | Hacker News Reader

Using automata is a bit silly and has problems. The biggest problems are vacuum welding and lack of lubrication. Vacuum welding can cause higher wear or even failure on metal components. Gears and cams absolutely need lubrication, which is liable to evaporation in a vacuum or requires exotic elements such as molybdenum.

Gears and cams also need to be machined, and machining processes do not work well in a vacuum for some of the same reasons mentioned above. That being said, one ton of microchips goes a long way. Why bother with automata, when simple vacuum tubes(in space, a vacuum tube is a couple funny shaped pieces of metal in close proximity) and magnetic amplifiers could be used to amplify signals from microcontrollers into something capable of doing useful work?

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> in space, a vacuum tube is a couple funny shaped pieces of metal in close proximity

I can't believe this never occurred to me before. The possibilities are staggering :-)

Author George O Smith went into great detail about space and vacuum tubes. Actually remember it as a great read.

Yeah... there will probably be less fouling, too, because most of the metal vapour will just float away. So the "tubes" should last longer, too.

Just spitballing: in a use case like TFA, building pieces and structures in/around an asteroid, would they not be subject to fouling by dust and debris from the processes going on around them?

Yes sure, but you can still do a lot of interesting stuff without having a lot of radio tubes. You can put up a thin "shield" some meters away.

Stuff doesn't have to be very rigid in many cases if it's built "in situ" in space.

Thanks!

I think you would still need the glass envelopes to prevent electrons roaming between devices.

Can they build a demo on earth? Maybe reshape a small hill-side into something fun or pretty with "Autonomous Restructuring". That would be fun to watch.

> Can they build a demo on earth? Maybe reshape a small hill-side into something fun or pretty with "Autonomous Restructuring". That would be fun to watch.

If you are restructuring an asteroid, containment isn’t much of a problem; if you want to do it to an isolated site on earth, it is more of a concern.

what is containment?

Containment is to stop the "turn everything into grey goo" robots from considering "Earth" to be part of "everything".

Oh lol we can handle a few sand-castle building robots. ChatGPT on the other hand...

Killdozer would like a word with you, sir.

> exotic elements such as molybdenum.

What? Molybdenum disulphide grease is available everywhere.

On asteroids it will be harder to obtain. It's been found to be present in iron meteorites at about 30 ppm[0]. [0]https://doi.org/10.1093/acrefore/9780190647926.013.206

It's not "exotic" in that it isn't used (it has major industrial Uses) but rather that it is one of the less common materials in the crust. It's less common than many of the "rare earth" elements and less common than uranium (Uranium is the 49th most common element while Molybdenum is the 58th depending on source https://en.wikipedia.org/wiki/Abundance_of_elements_in_Earth... ).

According to your source it is 20th in terms of annual production. Ahead of tungsten and vanadium and a lot of other often used elements like silver.

Why not just move the asteroid or pieces of the asteroid into a pressurized environment?

Because of the large scale and also because that would be an extra step. This methodology works best if the problem of construction in space has some solution.

Is it an extra step? Like a lot of this stuff is going to end up being used by humans in space so it needs to be pressurized at some point.

It doesn't even need to be anywhere near full pressure or breathable gas either.

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