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Comment by AmericanOP | Hacker News Reader

Unfortunately computers generate heat, so while Elon can build a business running on hot air on earth, he will not be able to do so in space.

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Are we to assume that nobody at the company who had launched more satellites than the rest of the planet combined is aware of this problem?

This is very far from an obstacle, space-functional radiators and thermal management systems do exist.

How much mass do we need to put in orbit to radiate 10 GW of data center heat? How much rocket fuel does it take to lift the rocket fuel required to lift that mass? Which part of this is cheaper or more effective than building data centers 100 feet below the ice in Antarctica ? Other than serving workloads that are already in orbit, I don't see the point. How much addressable market do we have for AI compute that is already in orbit?

The appeal is solar power efficiency gains. And yes it is a notable amount of extra mass, but not a deal-breaking amount. Latency is pretty minimal regardless of location (sub-100ms) which is not nothing but it's minor for things like serving AI inference.

Not saying I think it's the best idea, but it is theoretically feasible.

When you say it is not deal-breaking - have you looked at any math? Real world data finds we need about 6kg of radiator surface to radiate 1kW. [0] . A 100MW datacenter would need about 600,000 KG just of radiator mass. ISS was only 450,000KG and it took 13 years to assemble. Meanwhile, we're projected to launch 600X that data center capacity on earth in just the next three years.

To say that this is pure folly is an understatement. It is not folly, and it is not foolishness. It is fraud.

One of the most cited papers: https://starcloudinc.github.io/wp.pdf

Does not contain the word "nuclear". Instead its just breathless gushing about how much more efficient the solar power is.

[0] https://arc.aiaa.org/doi/epdf/10.2514/1.A35030

I’m not even worried about the weight and heat. How do you do a disk swap or other service on a machine in a datacenter in orbit?

KW scale radiators for GW scale compute demand. It is not based in reality.

it actually is not that impossible, and in fact can be done in a form factor not that different from Starlink satellites: https://www.youtube.com/watch?v=FlQYU3m1e80

I didn't say impossible, I said not based in reality. Why would you do this? What economic advantage is gained?

The radiators on the ISS radiate maybe 200kW all up. That's _one rack_ in a normal earthbound DC.

Under rated comment. May be legendary some day.

Radiative heat transfer exists in space. In fact, it works quite well for cooling as long as you’re in the shade.

It exists, but "works quite well" is only for a small amount of heat. It takes a big radiator to get rid of heat to ax vacuum. Much easier and cheaper to just keep the computers on earth and cool them with standard air or liquid cooling setups.

The required radiator for cooling isn’t that much larger than the required solar panel for powering the thing in the first place, and you don’t see everyone saying those are impossible. Is it easier to keep them on the ground? Obviously, but that wasn’t the claim. It just isn’t nearly as hard to cool things in space as a lot of people seem to think.

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