https://taranis.ie/datacenters-in-space-are-a-terrible-horri...
I don't have any specialized knowledge of the physics but I saw an article suggesting the real reason for the push to build them in space is to hedge against political pushback preventing construction on Earth.
I can't find the original article but here is one about datacenter pushback:
https://www.bloomberg.com/opinion/articles/2025-08-20/ai-and...
But even if political pushback on Earth is the real reason, it still seems datacenters in space are extremely technically challenging/impossible to build.
The author uses the power capacity of the ISS's solar panels as a point of comparison, but SpaceX has already successfully deployed many times that capacity in Starlink satellites[1] without even needing to use Starship, and obviously the heat dissipation problem for those satellites has already been solved so there's little point in hand-wringing about that.
The author also worries about ground communication bandwidth, claiming it is "difficult to get much more than about 1Gbps reliably", which seems completely ignorant of the fact that Starlink already has a capacity much greater than that.
The only unsolved technical challenge I see in that article is radiation tolerance. It's unclear how big of a problem that will actually be in practice. But SpaceX probably has more experience with that than anyone other than perhaps NASA so if they think it can be done I don't see much reason to doubt them.
Ultimately I think this is doable from a technical perspective, it's just a question of whether it will be economical. Traditional wisdom would say no even just due to launch costs, but if SpaceX can get Starship working reliably that could alter the equation a lot. We'll see. This could turn out to be a boondoggle, or it could be the next Starlink. The prospect of 24/7 solar power with no need for battery storage or ground infrastructure does seem tempting.
[1]: https://www.reddit.com/r/spacex/comments/zzwpue/with_starlin...
Your link here isn't really a fair comparison, and also you're still short a factor of 10x. Starlink has deployed 50x the ISS's solar cap across its entire fleet (admittedly 3 years ago); the author's calcs are 500x the ISS for one datacenter.
> and obviously the heat dissipation problem for those satellites has already been solved so there's little point in hand-wringing about that.
This reasoning doesn't make any sense to me, the heat dissipation issues seem very much unresolved. A single Starlink satellite is using power in the order of watts, a datacenter is hitting like O(1/10) of gigawatts. The heat dissipation problem is literally orders of magnitude more difficult for each DC than for their current fleet. This is like saying that your gaming PC will never overheat because NetGear already solved heat dissipation in their routers.
> The author also worries about ground communication bandwidth, claiming it is "difficult to get much more than about 1Gbps reliably", which seems completely ignorant of the fact that Starlink already has a capacity much greater than that.
Don't their current satellites have like 100Gbps capacity max? Do you have any idea how many 100Gbps routers go into connecting a single datacenter to the WAN? Or to each other (since intrahall model training is table stakes these days). They have at most like O(1)Pbps across their entire fleet (based on O(10K) satellites deployed and assuming they have no failover protection). They would need to entirely abandon their consumer base and use their entire fleet to support up/down + interconnections for just 2 or 3 datacenters. They would basically need to redeploy a sizeable chunk of their entire fleet every time they launched a DC.
So 3 years ago they managed to get to 10% of the power budget of one data center by accident, using satellites not explicitly designed for that purpose, using a partially reusable launch platform with 1/10th the payload capacity of Starship. My point is they've already demonstrated they can do this at the scale that's needed.
> A single Starlink satellite is using power in the order of watts
Then why does each satellite have a 6 kW solar array? Re-read that post I linked; the analysis is pretty thorough.
> Don't their current satellites have like 100Gbps capacity max?
Gen 3 is reportedly up to 1 Tbps ground link capacity, for one satellite.[1] There will be thousands.
> Do you have any idea how many 100Gbps routers go into connecting a single datacenter to the WAN? Or to each other (since intrahall model training is table stakes these days).
Intra-satellite connections use the laser links and would not consume any ground link capacity.
You're also ignoring that this is explicitly being pitched as a solution for compute-heavy workloads (AI training and inference) not bandwidth-heavy workloads.
How was it by accident? You make it sound like it was easy rather than a total revolution of the space industry? To achieve 1/10th of what they would need for a single DC (and most industry leaders have 5 or 6)? Demonstrating they could generate power at DC scale would be actually standing up a gigawatt of orbital power generation, IMO. And again, this is across thousands of units. They either have to build this capacity all in for a single DC, or somehow consolidate the power from thousands of satellites.
> Then why does each satellite have a 6 kW solar array? Re-read that post I linked; the analysis is pretty thorough.
You're right, my bad. So they're only short like 6 orders of magnitude instead of 9? Still seems massively disingenuous to conclude that they've solved the heat transfer issue.
> Gen 3 is reportedly up to 1 Tbps ground link capacity, for one satellite.[1] There will be thousands.
Okay I'll concede this one, they could probably get the data up and down. What's the latency like?
I say by accident because high power capacity wasn't a design goal of Starlink, merely a side effect of deploying a communications network.
> My bad. So they're only short like 6 orders of magnitude instead of 9?
No, they're 1 order of magnitude off. (22 MW total capacity of the constellation vs your bar of 100 MW for a single DC.) Again, 3 years ago, using an inferior launch platform, without that even being a design goal.
> What's the latency like?
Starlink latency is quite good, about 30ms round trip for real-world customers on the ground connecting through the constellation to another site on the ground. Sun synchronous orbit would add another ms or two for speed of light delay.
AFAIK nobody outside SpaceX has metrics on intra-satilite latency using the laser links but I have no reason to think it would be materially worse than a direct fiber connection provided the satellites aren't spread out too far. (Starlink sats are very spread out, but you obviously wouldn't do that for a data center.)
Why on earth would you compare their entire fleet to one project? Power generation trivially parallelizes only if you can transmit power between generation sites. Unless they've figure out how to beam power between satellites the appropriate comparison is 6Kw to 100Mw. And again, the generation is the easy side; the heat dissipation absolutely does not parallelize so that also needs to go by 3-5 orders of mag.
And also: radiation. Terrestrial GPUs are going to be substantially more power and heat efficient than space-based ones (as outlined in TFA). All this for what benefits? An additional 1.4x boost in solar power availability? There's simply no way the unit economics of this work out. Satellite communications have fundamental advantages over terrestrial networks if you can get the launch economics right. Orbital DCs have only the solar availability thing; everything else is cheaper and easier on land.