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> Only downsides are .... Yeah the only downsides are those you listed, and about 1000 others. Anybody that is serious about data centers on the moon should h

> Only downsides are .... Yeah the only downsides are those you listed, and about 1000 others. Anybody that is serious about data centers on the moon should have their brain examined.

ben_w 9mo ago
IMO, they're bad, but not so bad as "have their brain examined". While they absolutely do have huge problems at current costs, and I don't trust Musk's estimates for future costs. It's not implausible that collectively humanity (well, China: it's not like the ESA appears to value cheap launches yet) is going to get launch costs down a lot further, something that makes the question of "how cheap is cheap enough?" worth asking. Then you can take a look at the existing constellations and their combined power throughput, look at whatever fraction of that power budget is not radiated by RF/laser output for comms, and trivially that's the power budget with minimal redesign for compute. IMO all of space is still not good enough to be worth caring about: the moon is about twice the difficulty of LEO, and LEO now getting to the point that we're seriously asking about Kessler cascades; but also in space the waste heat is currently only a problem with no currently-useful side-effects, whereas down here on Earth we have possibilities for using the waste heat as an industrial input, e.g. using DCs as the heat source for district heating, or combining with ocean water to become evaporative desalination (which is otherwise pointlessly energy-intensive). That, and the arguments about space-based power is as yet still marginal given how hostile an environment space itself is to PV. And PV on the moon doesn't even get the advantages (launch cost or ~24h light) of PV in a sun-synchronous orbit around Earth.* But it's close enough to not be insane to do a real engineering analysis. Even if the answer turns out to still be 10x more expensive than the ground, which is what I'm expecting it to be. * Side note: for a while I've noticed that China has production and money to afford to build a global power grid on Earth with 1 Ω resistance the long way around. This would allow 24h PV everywhere from deserts on the other side of the world including across seasons. Less material would be required to do this on the Moon because it's smaller, and also you don't really need to go across the equator so it can be much shorter, but also this would need someone to put an aluminium plant onto the moon that has negligible consumables and IIRC we don't have one of those yet. Still, if moon-base design were up to me, I'd suggest sending up 1000 km of HVDC cable on some early missions and put a ring around one of the poles, with some PV every 60° or so. This is still not a sensible design for moon-based compute.
- panick21_ 9mo ago
  10x is very very optimistic. Practically it would be more. Even if you assume launch cost = zero its most expensive and less practical. And the moon is even worse. Still you can assume launch cost = zero. But energy is one part, to actually reliably land on the moon with your whole infrastructure. Connecting all that infrastucture up with power and everything else. Your basically doing a gigantic civil engineering project all with only roboitcs, while we can't even do a civil engineering project on earths with only robots. And if your going moon, nuclear is clearly the better option then solar towers. And if you go nuclear anyway, just do it on earth.
  - ben_w 9mo ago
    I basically agree with you. Even where I said 10x, because I am indeed an optimistic person. The other stuff… well, I think it's worth the analysis, even when the answer ends up not just "no", but "hell no!". Analysis is much cheaper than actually going to space, after all.
    - godelski 9mo ago
      I mean tbh the problem was that Nevermark was making strong claims without the actual analysis. There's a lot of analysis out there already but he wasn't even doing the simple ones. There's a lot of armchair experts on space. Look, I'd love to do more things in space, but we'll never be able to do them if we lie our way and aren't realistic at the costs, and benefits. It just creates strawmen that are trivial to tear down. The armchair experts aren't helping, they're hurting.
- godelski 9mo ago
  > Even if the answer turns out to still be 10x more expensive than the ground You're off by at least an order of magnitude. Using Musk's optimistic numbers, to put things into LEO, it is >$1k/kg for single reuse, ~$100/kg with ~5 reuses, and <$50/kg with like 50 reuses. That's to LEO. Moon is way more expensive. > I'd suggest sending up 1000 km of HVDC cable I'm sorry, WHAT? I'll let you do the math on that one, because that stuff is not light weight... We're talking several kg/m minimum... Then consider payload... You're being pretty cavalier about all the hard things... You can't just hand wave away these details because these "details" are just a fraction of what makes all of this so difficult.

> Only downsides are .... Yeah the only downsides are those you listed, and about 1000 others. Anybody that is serious about data centers on the moon should have their brain examined.

ben_w 9mo ago

IMO, they're bad, but not so bad as "have their brain examined". While they absolutely do have huge problems at current costs, and I don't trust Musk's estimates for future costs. It's not implausible that collectively humanity (well, China: it's not like the ESA appears to value cheap launches yet) is going to get launch costs down a lot further, something that makes the question of "how cheap is cheap enough?" worth asking. Then you can take a look at the existing constellations and their combined power throughput, look at whatever fraction of that power budget is not radiated by RF/laser output for comms, and trivially that's the power budget with minimal redesign for compute. IMO all of space is still not good enough to be worth caring about: the moon is about twice the difficulty of LEO, and LEO now getting to the point that we're seriously asking about Kessler cascades; but also in space the waste heat is currently only a problem with no currently-useful side-effects, whereas down here on Earth we have possibilities for using the waste heat as an industrial input, e.g. using DCs as the heat source for district heating, or combining with ocean water to become evaporative desalination (which is otherwise pointlessly energy-intensive). That, and the arguments about space-based power is as yet still marginal given how hostile an environment space itself is to PV. And PV on the moon doesn't even get the advantages (launch cost or ~24h light) of PV in a sun-synchronous orbit around Earth.* But it's close enough to not be insane to do a real engineering analysis. Even if the answer turns out to still be 10x more expensive than the ground, which is what I'm expecting it to be. * Side note: for a while I've noticed that China has production and money to afford to build a global power grid on Earth with 1 Ω resistance the long way around. This would allow 24h PV everywhere from deserts on the other side of the world including across seasons. Less material would be required to do this on the Moon because it's smaller, and also you don't really need to go across the equator so it can be much shorter, but also this would need someone to put an aluminium plant onto the moon that has negligible consumables and IIRC we don't have one of those yet. Still, if moon-base design were up to me, I'd suggest sending up 1000 km of HVDC cable on some early missions and put a ring around one of the poles, with some PV every 60° or so. This is still not a sensible design for moon-based compute.

panick21_ 9mo ago
10x is very very optimistic. Practically it would be more. Even if you assume launch cost = zero its most expensive and less practical. And the moon is even worse. Still you can assume launch cost = zero. But energy is one part, to actually reliably land on the moon with your whole infrastructure. Connecting all that infrastucture up with power and everything else. Your basically doing a gigantic civil engineering project all with only roboitcs, while we can't even do a civil engineering project on earths with only robots. And if your going moon, nuclear is clearly the better option then solar towers. And if you go nuclear anyway, just do it on earth.
- ben_w 9mo ago
  I basically agree with you. Even where I said 10x, because I am indeed an optimistic person. The other stuff… well, I think it's worth the analysis, even when the answer ends up not just "no", but "hell no!". Analysis is much cheaper than actually going to space, after all.
  - godelski 9mo ago
    I mean tbh the problem was that Nevermark was making strong claims without the actual analysis. There's a lot of analysis out there already but he wasn't even doing the simple ones. There's a lot of armchair experts on space. Look, I'd love to do more things in space, but we'll never be able to do them if we lie our way and aren't realistic at the costs, and benefits. It just creates strawmen that are trivial to tear down. The armchair experts aren't helping, they're hurting.
godelski 9mo ago
> Even if the answer turns out to still be 10x more expensive than the ground You're off by at least an order of magnitude. Using Musk's optimistic numbers, to put things into LEO, it is >$1k/kg for single reuse, ~$100/kg with ~5 reuses, and <$50/kg with like 50 reuses. That's to LEO. Moon is way more expensive. > I'd suggest sending up 1000 km of HVDC cable I'm sorry, WHAT? I'll let you do the math on that one, because that stuff is not light weight... We're talking several kg/m minimum... Then consider payload... You're being pretty cavalier about all the hard things... You can't just hand wave away these details because these "details" are just a fraction of what makes all of this so difficult.