[dahinds]

This isn't really true, though? The ISS does it with radiators that are ~1/2 the area of its solar panels, and both should scale linearly with power?

[alangibson]

ISS radiators run on water and ammonia. Think about how much a kg costs to lift to space and you'll see the economics of space data centers fall apart real fast. Plus, if the radiator springs a leak the satellite is scrap.

[trothamel]

The point of the Starship program is to drop the cost of a kg going to space significantly - this isn't meant to be launched with rockets that aren't fully reusable.

[duped]

Even if power cost nothing the limiting factor on data center value creation is distance to where the data is requested. Putting it in space is dumb.

[wild_egg]

The ISS creates radically less heat than a datacenter

[IvyMike]

I don't pretend to understand the thermodynamics of all of this to do an actual calculation, but note that the ISS spends half its time in the shadow of the earth, which these satellites would not do.

[hwillis]

The earth is actually a pretty big heat source in space. Solar radiation is a point source, so you can orient parallel to the rays and avoid it. The earth takes up about half the sky and is unavoidable. The earth also radiates infrared, the same as your radiators, so you can't reflect it. Solar light is in the visible spectrum so you can paint your radiators to be reflective in visible wavelengths but emissive in infrared.

Low satellites are still cooler in the Earth's shadow than they would be in unshadowed orbits, but higher orbits are cooler than either. Not where you'd want to put millions of datacenters though.

[smw]

Wouldn't they?

[el_nahual]

Radiator size scales linearly with power but, crucially, coolant power, pumps, etc do not.

Imagine the capillary/friction losses, the force required, and the energy use(!) required to pump ammonia through a football-field sized radiator panel.

[FinnKuhn]

Additionally, I feel like a datacenter is going to produce a LOT more heat than the ISS.

[nomilk]

Also, space solar is around 4-8x more efficient (24h/day full sun instead of ~4-8 on Earth), and 40% gain due to no atmospheric loss.

[blitzar]

However, you can drive the computer and 100x the solar panels to the middle of nowhere for 1/1,000,000th of the cost.

[wongarsu]

Moving electricity long distance is a lot easier than moving coolant long distances, which puts a soft limit on the reasonable size of the solar array of these satellites. But as long as you stay below that and pick a reasonable orbit it's indeed not too bad, you just have to properly plan for it

[invalidusernam3]

Here's an interesting post linked elsewhere in this thread https://taranis.ie/datacenters-in-space-are-a-terrible-horri...

[FireBeyond]

The ISS isn't consuming and generating megawatts+ of power.

[dahinds]

Yes but if the solar panel area scales linearly with radiator area, the problem doesn't get worse?