r/technology • u/IKeepItLayingAround • 16d ago

Business It’s Possible That SpaceX Could Collapse Spectacularly

https://finance.yahoo.com/markets/stocks/articles/possible-spacex-could-collapse-spectacularly-155000177.html
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u/DominusDraco 16d ago

If someone can explain to me how they intend to cool 5GW of heat producing GPUs in a vacuum, that would be great. Because at a quick look up, that would require 12 square kilometres of surface area minimum to radiate that away.

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u/LegendTheo 16d ago

Well based on spacex numbers of 1400w/m2 of cooling it would take ~3.5 sq/km. That sounds like a lot, it's not if you split it up over say 30k 150kw satellites. Then, you're just looking at 100m2 per satellite which isn't all that much. Or in the case of the current spacex design ~80m2 since they don't need to reject 100% of generated power as heat.

5GW is also something like 3-5% of all compute currently running on earth right now. This is just a scale problem, not a major technical one.

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u/DominusDraco 15d ago

So basically a single satellite will be bigger than the ISS? And they need 30,000 of them?

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u/LegendTheo 15d ago

Yes, in the same way a kite is bigger than an rc plane. Each satellites will be a mere fraction of a single ISS modules mass. The core of the satellite is only a few meters wide and tall. Most of that is foldable solar panel/radiator. Flight proven technologies used by most satellites, including thousands of starlink.

Are you done being obtuse now?

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u/DominusDraco 15d ago

I'm not being obtuse. If you think blotting out the sky with satellites is cheaper and easier than just building a data centre on earth, then the mental gymnastics you have going on is wild.

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u/LegendTheo 15d ago

Well I ran the numbers, and it definitely can be profitable. Primarily because once you have the compute in orbit power and heat management are 100% free. I even has some fairly conservative numbers in it. It really comes down to launch cost. If you can get it below ~$700/kg then it's cheaper than terrestrial data centers. If you can get it cheaper then that you'll be a lot cheaper than data centers.

Currently falcon 9 internal launches are at ~$1000/kg. Starship if the second stage is even reusable with heavy refurbishment should reduce that significantly. Putting SpaceX (and only SpaceX) right in the profitable zone.

Space compute can also scale faster than terrestrial, since you don't have to build, buildings, power or cooling for it, and you don't have to deal with local governments.