[Ajedi32]

> 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.

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.

[1]: https://starlink.com/updates/network-update

[tech_ken]

> 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 scale.

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?

[Ajedi32]

> How was it by accident?

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.)

[tech_ken]

> 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.)

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.

[Ajedi32]

Why wouldn't you compare to the entire fleet? You think they're going to deploy an entire data center in one sat? That'd be as dumb as trying to deploy an entire data center in one rack back on Earth. Of course if you frame the problem that way it seems impossible.

I already gave my thoughts on radiation and economics in my original comment. I agree those could be significant challenges, but ones SpaceX has a plausible path to solving. Starship in particular will be key on the economic side; I find it very unlikely they'll be able to make the math work with just Falcon 9. Even with Starship it might not work out.

And it's not just a 1.4x boost in solar power availability. You also eliminate the need for batteries to maintain power during the night or cloudy days (or cloudy weeks), and the need for ground infrastructure (land, permitting, buildings, fire suppression systems, parking lots, physical security, utility hook-up, etc).