[randallsquared]

In fact, not even 1% of the power usage of a datacenter...

Right, but SpaceX has already filed plans with the FCC to launch a million of them, which is to say, 10K of your datacenter units. Tying back to the article, this plan is definitely going to require Starship and airline-like operations.

[Symmetry]

Yeah. I don't have any doubts that this is something that can be done. But doing it cheaply enough to be worth while is the difficult bit. Elon does have reputation for delivering impressive things, but not for finishing them on the deadlines he sets.

[saberience]

Ok, how many Starship launches have there been so far? Ok, 11 tests, of which only one has sent a dummy payload. Of the 11 tests, you can say that the latest one was closest to a final (sort of) working version. So we're still very early in the Starship launch program.

Let's do the math on "millions of datacenters" worth of launches.

In fact, let's try and do it for a single 50k GPU datacenter:

50,000 GPUs at GB200 density = 695 NVL72 racks at 1360 kg (1.36 tonnes) each, so the racks are roughly 950 tonnes.

GPUS = 950 tons

85MW of power needed for the GPUs. Latest solar power panels give roughly 120-150 watts per kg. Let's be generous and say 150 W/kg. So 85 MW / 150 W/kg = 570 tonnes of solar arrays

Power = 570 tons

Thermal management (radiators). Real space radiators are around 12 kg/m² for a heavy deployable radiator and its support structure, though ISS radiators are 8 kg per square meter, or 2.75 kg/m² if we only consider the exposed panels. (Using 8 kg/m² for an estimate). 200,000 m² × 8 kg/m² = 1,600 tonnes of radiators

Plus working fluid (ammonia or similar), pumps, manifolds, redundant loops: 150 tonnes.

Radiators Total: 1750 tons.

Structure, Propulsion, Comms, Avionics, Attitude Control Systems, plus Margin. Hard to estimate but conservatively several hundred tons extra. (Actual spacecraft programs always add roughly 20-30% mass margin).

Extras: 750 tons. (being very conservative).

Total = 950+570+1750+750 = 4020 tons.

And note, this is for a single 50k GPU datacenter with all the numbers being skewed to most optimistic.

That would be 40 (!!!) Starship launches. So far we've had 11 launches total with none being successful (100% successful I mean). Each of those launches currently costs 90M dollars. And note, we are assuming a fully working 100 ton payload for Starship of which none of the launches so far have been close to at all.

So our full datacenter to space would cost 3.6B dollars (at current SpaceX prices)... (just to launch it, not to actually buy the equipment). And realistically would cost far more than that...

Note, this is for (by today's standards) a small datacenter with only 50k GPUs and I haven't included any testing, R&D costs, costs of "maintenance", station keeping, replacements, etc etc.

Let alone the question of huge amounts more satellites in orbit, risks of space junk, Kessler syndrome, etc etc.

[db48x]

You’re way overestimating the size of the radiators needed. Then you overestimate their mass, because the ISS has huge heavy radiators that operate at <30°C. A rack of computers can run at much higher temperatures and therefore need much smaller, lighter radiators. The radiators would be smaller and lighter than the solar panels.

[randallsquared]

I have a lot of miscellaneous quibbles with your assumptions and numbers, but even if you grant many of them, 40 launches is not many for Starship's planned cadence. HLS is going to require 10-16 Starship launches just to get it fueled enough for one landing, and they have to be close enough together to minimize boil-off.

[saberience]

BTW, for these numbers I was very much skewing them to be MOST favorable for SpaceX!

Happy to debate though! I love this topic.