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[return to "Data centers in space makes no sense"]
1. elamje+ba1[view] [source] 2026-02-04 02:16:32
>>ajyoon+(OP)
I was talking to someone about this the other day. I was part of a team at NASA that developed a cooling system for the ISS and this whole premise makes no sense to me.

1. Getting things to space is incredibly expensive

2. Ingress/egress are almost always a major bottleneck - how is bandwidth cheaper in space?

3. Chips must be “Rad-hard” - that is do more error correcting from ionizing radiation - there were entire teams at NASA dedicated to special hardware for this.

4. Gravity and atmospheric pressure actually do wonders for easy cooling. Heat is not dissipated in space like we are all used to and you must burn additional energy trying to move the heat generated away from source.

5. Energy production will be cheaper from earth due to mass manufacturing of necessary components in energy systems - space energy systems need novel technology where economies of scale are lost.

Would love for someone to make the case for why it actually makes total sense, because it’s really hard to see for me!

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2. mike_h+TW1[view] [source] 2026-02-04 09:33:10
>>elamje+ba1
It sounds hard but it shouldn't not make sense.

1. Solving cost of launching mass has been the entire premise of SpaceX since day one and they have the track record.

2. Ingress/egress aren't at all bottlenecks for inferencing. The bytes you get before you max out a context window are trivial, especially after compression. If you're thinking about latency, chat latencies are already quite high and there's going to be plenty of non-latency sensitive workloads in future (think coding agents left running for hours on their own inside sandboxes).

3. This could be an issue, but inferencing can be tolerant to errors as it's already non-deterministic and models can 'recover' from bad tokens if there aren't too many of them. If you do immersion cooling then the coolant will protect the chips from radiation as well.

4. There is probably plenty of scope to optimize space radiators. It was never a priority until now and is "just" an engineering problem.

5. What mass manufacture? Energy production for AI datacenters is currently bottlenecked on Siemens and others refusing to ramp up production of combined cycle gas turbines. They're converting old jet engines into power plants to work around this bottleneck. Ground solar is simply not being considered by anyone in the industry because even at AI spending levels they can't store enough power in batteries to ride out the night or low power cloudy days. That's not an issue in space where the huge amount of Chinese PV overproduction can be used 24/7.

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3. Frankl+u22[view] [source] 2026-02-04 10:15:28
>>mike_h+TW1
> There is probably plenty of scope to optimize space radiators. It was never a priority until now and is "just" an engineering problem.

Well, it's a physics problem. The engineering solution is possibly not cost efficient. I'd put a lot of money that it isn't.

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4. Ajedi3+LH2[view] [source] 2026-02-04 14:51:33
>>Frankl+u22
What makes you so sure? SpaceX already has thousands of 6 kW networking racks flying around in LEO and they dissipate their heat just fine, and are plenty cost-effective. You think they can't do any better than that with a new design specifically optimized for computing rather than networking?
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5. unders+dr3[view] [source] 2026-02-04 18:09:08
>>Ajedi3+LH2
The solar panels on the newest satellites can deliver 6kW but the power that satellite actually uses is less. The satellite is only using 300W[1] during the dark phase of it's orbit when it can use it's entire mass to cool down. Is that limit because of the battery or is it because the satellite needs to radiate all the heat it acquired from the other half of the time in the sun?

[1] https://lilibots.blogspot.com/2020/04/starlink-satellite-dim...

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6. Ajedi3+Ws3[view] [source] 2026-02-04 18:15:50
>>unders+dr3
Looks like that's a purely speculative assumption the blog author made, not a fact. I'm not sure why he made that assumption given that Starlink doesn't actually stop working at night.

Fair point that in SSO you'd need 2-3x the radiator area (and half the solar panels, and minimal/no batteries). I don't think that invalidates my point though.

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7. unders+qw4[view] [source] 2026-02-04 23:35:24
>>Ajedi3+Ws3
Article doesn't say the satellites stop working in their dark phase, it says they consume 300W in the dark phase based on some battery math.
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