Comment by Nevermark

Comment by Nevermark 3 days ago

SpaceX is rockets, now global satellite internet, ...

To credibly harness off-world resources at any scale, there are going to need to be automated refueling depots and many kinds of robotic automation for resource extraction. With the Asteroid Belt looking amazing for quantity and accessibility of resources.

That would also completely remove the lid on how many $ trillions of market cap SpaceX could accrue.

So I find it ironic that Tesla is moving away from cars as product, and still talking up humanoid robots, which as yet are not a product, and as research don't seem to have an edge on anyone.

ALSO: Data centers on the moon make more sense than data centers in orbit. Obviously where latency isn't king, but compute is. Simple cooling sinks, dense (low local latency) expansion, dense (efficient) maintenance, etc.

godelski 3 days ago

  > Simple cooling sinks, dense

I think you need to go back to physics class. You seem to not even understand the very basics of heat transfer. You need more than "cold". I'll give you a hint, the problem is the same problem as "in space no one can hear you scream."

I'll also mention that the moon isn't very cold, except on the dark side. In the moon's day the temperature is 120C and at night -130C. The same side of the moon always faces us and the moon isn't always full. I'll let you figure out the rest.

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Nevermark 3 days ago

> You seem to not even understand the very basics of heat transfer.
Basic physics: The moon is very cold in surface shadows and below the surface. It is an enormous pre-chilled heat sink.
The surface is also the support structure for any scale of radiative cooling with the same heat physics as orbit, but much better for larger and enhanced radiative engineering.
For example, heat pumps can centralize waste heat energy. Higher heat density vastly increases radiative efficiency.
• Permanent shadow: 40-60 ˚K, -230 to 210 ˚C
• In polar shadow: 25-30 ˚K, -250 to -245 ˚C
• Under 1 meter of surface, equatorial: 250 ˚K, -23 ˚C
• Under 1 meter of surface, polar: 200-220 ˚K, -75 to -50 ˚C
Many advantages beyond unlimited heat sink/radiative area: all compute in one place, i.e no size limit, so low inter-center latencies, no orbit safety negotiations or periodic orbit re-lifts required, able to update entire data center in a single trip, easier maintenance and stability in gravity on a surface, solar panels can be distributed over distance limiting total space debris risk, different component lifetimes don't result in wasted components, ...
Only downsides are a higher Earth-Datacenter latency, lunar dust resistant design, and a need to be at a pole for all-month solar power.
Nuclear power, or nuclear + solar, would allow any site.
Note that shade can be created anywhere on the surface via reflective shielding, and power can be used to heat, in order to stabilize temperatures in a desired band. Buried installations can use insulation for even greater temperature control.

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- habinero 3 days ago
  
  > The moon is very cold in surface shadows and below the surface. It is an enormous pre-chilled heat sink
  Technically true, but not really. "Radiative cooling" is heat loss through thermal radiation and it's really ineffective. We use air cooling / water cooling for a reason.
  Satellites and spacecraft are engineered to make sure they can shed enough heat and they use a fraction of the power a datacenter would. All that energy eventually gets turned into heat, and it has to go somewhere.
  It's a ridiculous idea that's never going to make even a tiny bit of economic sense.
  
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- direwolf20 3 days ago
  
  Is the moon in space? I guess us-east-1 is also a space data center, if you think about it.
  
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- panick21_ 2 days ago
  
  > 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.
  
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- godelski 3 days ago
  
  Great, now do the math and let's talk
  
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  Nevermark 3 days ago
  
  Things scale so differently, we don’t need a parts list to make a general tradeoff relationship.
  Of the moon and orbital, orbit is much closer and will be cheaper to start with.
  But a lunar site would scale to much greater mean density and unlimited total capacities. And be much cheaper for reasons I gave, at some threshold scale.
  Neither is easy, and it’s not at all clear that either is actually better than down here. Especially with nuclear efforts and funding rising quickly.
  
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NetMageSCW 3 days ago

Well, there are the permanently dark crater bottoms that might contain water ice and are definitely very cold. Turn the water ice into thermal transfer fluid and drill (The Boring Company) cooling loops underneath and the try to heat sink into the very cold ground. I’m sure you could run the Data Center for months before you exceed the radiative heat dispersal available to the ground.

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- godelski 3 days ago
  
  You don't need to but in a dark crater to use the ground as your sink.
  Also you need to consider that the thermal conductivity of lunar regolith is quite low.
  I'm not saying it's not possible but I am saying there's a lot of technical challenges that make naïve approaches not so simple. The reason doing things in space is hard is not just the difficulty of getting things up into space. It's that all the things you take for granted just don't work.
  Oversimplification is a footgun. Or more accurately, in this case a foot taser (if you know why you've found one of the major challenges of doing anything on the moon and mars)
  
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falcor84 3 days ago

If cooling is such an important factor compared to everything else, I would assume we should see data centers in Antarctica long before we see them on the Moon.

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Nevermark 3 days ago

Thanks. That is a very good point. Or Greenland, to be topical.

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worik 3 days ago

> With the Asteroid Belt looking amazing for quantity and accessibility of resources.

Watch out universe, here we come!

What could possibly go wrong, mining asteroids? An awful lot, when we start messing with orbital dynamics in the asteroid belt.

But Space X can externalise those risks. It will probably be centuries before disturbed orbits start to threaten Earth... So who cares?

Me.

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ianburrell 3 days ago

I always wonder what resources from asteroid belt do we need on Earth. We have plenty of iron and aluminum for building things. Lithium and rare earths aren't available in asteroids. Gold isn't worth grinding up whole asteroid.
Asteroid resources would be useful for building in space, but that is getting a step ahead.

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- mrguyorama 3 days ago
  
  Asteroid mining in our current economy is about pointing at the market price of an extremely low supply element that isn't that high demand in the first place and forgetting to talk about what a supply glut does to price.
  Everyone is laboring under this subtle belief that space industry will be just like scifi speculated, but scifi stories always treated space like the ocean, with lots of interplanetary trade and easy travel and no consideration of energy (because it makes for good storytelling) but the actual energy budgeting and consideration of gravity wells is the exact opposite of ocean transport.
  Global trade works at all because buoyancy and fluid physics make ocean vessels stupidly efficient at transport.
  Moving any matter through space is stupidly inefficient.
  The tyranny of the rocket equation constrains everything.
  
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slumberlust 3 days ago

The expanse and A City on Mars covers the risk pretty well.

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boogrpants 3 days ago

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habinero 3 days ago

Elon's not doing any of that and never will lol. You're vastly underestimating the cost and complexity of doing anything in space.

Sure, an asteroid theoretically has eighty quadrillion dollars of whatever, but you're going to spend ninety bajillion getting anything there and back, plus you'd ...well, crater the market even if you did.

We're not hurting for heat sinks. There's the entire ocean to work with, for one.