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Comment by microtonal | Hacker News Reader

Except that doing this at scale is currently still a pipe dream. Space is a near-vacuum, so it's hard to get rid of the heat.

The active thermal control system (ATCS) on the ISS uses an ammonia loop and radiators measuring 13.6 x 3.12 meters, or about 42.5 square meters. It can dissipate 16 kW, which is enough for 16 H200s, or one-quarter of a rack on Earth. For 200 kW, you would need a system 12.5 times larger, about 531 square meters—2.6 times larger than the solar array. The satellite would be enormous, larger than the ISS, and all of that for only three racks.

https://codedtrip.com/en/blog/data-centers-in-space-disastro...

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> For 200 kW, you would need a system 12.5 times larger, about 531 square meters—2.6 times larger than the solar array. The satellite would be enormous, larger than the ISS, and all of that for only three racks.

Starlink gen 3 satellite is designed to dissipate 250 kW. You are talking about an already solved issue, with real hardware already being built today.

Are you asserting that we must use the exact same heat rejection architecture the ISS uses for data centers?

https://en.wikipedia.org/wiki/Liquid_droplet_radiator

The problem of the $ per kg to launch huge radiators and "orbital datacenter" type stuff of satellites into space doesn't seem to be resolving itself any time soon. Even if we hand wave away and say that 5 years from now the starship will be such a spectacular success than it costs only $200 per kg to send stuff into space (drastically lower than what it costs now), it would still be vastly less expensive to build a terrestrial solar datacenter in the middle of the southern Libyan desert than it would be to do the same amount of compute in space.

> it would still be vastly less expensive to build a terrestrial solar datacenter in the middle of the southern Libyan desert than it would be to do the same amount of compute in space.

Perhaps, but the parent comment posited that some people would pay the premium for orbital data center due to much better security. At $200 per kg to orbit, it could make sense.

With the caveat that Libya, being located upon Earth, is affected by solar power not working at night or when it's cloudy, and is also subject to being in Libya, which is a country with bureaucrats that are going to subject anything built in the country to their laws.

So the "some day in the future" orbiting data centers proposed by a known fraudster will use an experimental-at-best radiator technology that has never been tested in flight yet? That tracks.

Orbital data center constellations are also studied by Google, the idea is not just from Elon.

> Space is a near-vacuum, so it's hard to get rid of the heat.

It's not that hard, Starlink constellation already dissipates around 100 MW of heat, split over many satellites. Any orbital datacenter would use similarly distributed satellites.

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