Comment on Datacenters in space are a terrible, horrible, no good idea.
brucethemoose@lemmy.world 7 hours agoPlugging it into this formula:
projectrho.com/public_html/rocket/heatrad.php
I get a circular radiator at least a kilometer wide, assuming the radiator is quite efficient, a rather modest datacenter, and very hot coolant (70C).
…Realistically, the coolant temperature would need to be much lower, and dissipate much more, so the area gets very large real quick.
I cannot emphasize how expensive a functional 2km+ radiator would be in space. It’s mind bogglingly expensive.
NotMyOldRedditName@lemmy.world 6 hours ago
For 100kW? I’m not going to try and figure things out from that massive site.
brucethemoose@lemmy.world 6 hours ago
100kW? Nvidia BGX 200 servers are 14kW each, not counting the interconnect, or anything else. According to nuggets I’ve read online, we’re talking 200 megawatts for an Earth-based AI datacenter these days, without something exotic like underclocked Cerebras WSEs
Plugging 200 megawatts into this:
www.calctool.org/…/stefan-boltzmann-law
I get about 0.46 square kilometers, depending on the coolant temperature and ultimate efficiency of the system.
I have no clue what the construction of such a monstrosity would look like, but if it was a simple 0.5 inch aluminum sheet, it would weigh like 15,000 metric tons.
NotMyOldRedditName@lemmy.world 6 hours ago
They aren’t making a datacenter like on earth. They’re putting up a ton of satellites that will each generate about 100kW.
Everyone keeps thinking they’re putting these massive things up there, they are not doing that.
brucethemoose@lemmy.world 6 hours ago
That’s interesting, but what’s the point? If it’s like 2 DGX boxes in each satellite, spaced out, the interconnect between them is going to be very slow, and the individual computational power of each satellite will not be that impressive.
And if you connect them all in one constructed mesh and wire them together, well, you’ve made a 200MW datacenter! The economies remain the same.
If hardware gets more power efficient, well… Then why do you need to go to space anymore?