You can only cool by radiation in space. You may get more energy from the sun but how are you going to get rid of all the heat fast enough?
You're concentrating it into a very small area of compute.
If you don't spread that heat back out, it's going to find a much higher thermal equilibrium than the solar panels themselves would find just absorbing the sunlight and radiating the energy back into space.
It's like you've pointed a magnifying glass at your compute, except with electricity, which means you can reach temperatures higher than you can with a magnifying glass.
It's the same way that Sam Altman talks about the risks of AI deciding to kill humanity: because that's dramatic and attention grabbing, and also the most unlikely outcome. Talking about it keeps us from talking about the real, ground level problems like the massive, unplanned-for disruption in jobs and education.
They just need to keep the money tap flowing, and tomorrow can worry about itself. Who's going to hold them accountable for data-centres-in-space five years from now, when they don't exist? Has Musk suffered any blowback from his hyping the Hyperloop that never materialized?
How many smart people worked quietly at Theranos, knowing that a drop sample from a thumb was incapable of carrying sufficient blood volume for a legitimate sample, but thought "hey, maybe someone will figure something miraculous out that violates a basic tenet of my professional experience"?
Grandparent is trying to argue that a lot of smart people working quietly on something confers plausibility upon the premise of their work (i.e., "they must know something you don't"). I've rebutted with two examples showing that large numbers of smart people working on something don't make plausible a premise that is obviously flawed for other reasons [*].
[*] (ETA) and is known at the time by the smart people.
It might even be useful in other circumstances. Better radiative cooling systems, hardening commercial high-end compute for space, etc etc. R&D you can feel proud of, even if your bosses are only paying you to do it to fleece rubes who think it's the next trillion dollar industry.
It’s not like only idiots who know nothing about space are pointing out the cooling issue: https://taranis.ie/datacenters-in-space-are-a-terrible-horri...
"you don't lose that much power through the atmosphere"
Assuming you can point the orbiting panels at the sun and remain direct, you lose 80% of your power through the atmosphere (from angle and day/night). On the ground you lose 25% even if your panel is directly below the sun pointed exactly at it, which is never the case in many latitudes.
And of course it's not trivial to radiate heat. But it's also a fairly simple mechanical problem. You pump the heat to spread it out, and radiate it. You've already got the surface area shaded by the panels (which is more than enough, because the panels don't absorb 100% of solar radiation).
Sure, you need a lot of them. Starship V3 is probably about to get us past 100 tons of payload capacity - even if they blow up a few first.
The key people miss is that you don't have to spend money on ongoing cooling once the thing is in space. This isn't going to save money now, but the cost lines are going to cross.
When people say "you don't lose that much power on the ground", it's in the context of cost.
So a solar panel is 5x more efficient in space. You solve that in the ground by buying 5x more solar panels.
Solar panels cost -- rounding up -- $10/kg.
Lifting things into space costs -- rounding down -- $1000/kg.
For the same amount of money, you can put 100X solar panels into a ground based array as a space based array. You don't lose that much power on the ground. You aren't overcoming that difference because solar panels are more efficient in space.