Comment by svantana
5 hours ago
The joint solar panel + computer system will be pretty close to an ideal black body, which near earth will have an average temperature of about 10°C. And radiation is an issue, but starlink seems to work so I don't see why this wouldn't.
Of course it works, the question is how this would look like and if its financial feasable.
You make a H100, ship it to a space dock, load it onto a rocket (rocket requires fuuel, the rocket, etc.) send it up, deploy it, monitor it live 24/7, have means of adjusting its orbit, if it breaks, its immediade full loss, otherwise it will degenerate faster in space than on earth, now it needs a high speed up/downlink to do anything reasonable which also requires a base station. The base station has to track this satelite.
One H100 costs 40k, consumes 700 Watt peak and need probably at a minimum 5 square meter of area for cooling and solar.
The colossus datacenter from musk has 250.000 of these.
Now you have to track 250.000 single satelites, you have to coordinate the communication between the, up and downlink to earth.
250.000 * 5 square meter of area.
This alone increases the potential debris in space.
And this is ONE 300 MW Datacenter replacement. ONE.
It’s very easy to overestimate the difficulty of cooling things in space, unless you actually run the numbers. So please follow along as Scott Manley runs the numbers: <https://www.youtube.com/watch?v=FlQYU3m1e80>.
Basically a Starlink v3 satellite has an estimated power budget of 20kW. Add in the heat absorbed from the environment (both directly from sunlight and reflected off of the Earth) and you’ll find that it must reject about 22kW of heat. That’s a fair amount, but at 65°C it can radiate it all away just using it’s own surface area! No radiator required at all!
Of course the power density of computer racks has been going up over the years. If you want to reach 100kW per satellite then they will need a modest radiator, but nothing extravagant. It would still be smaller than the solar panels, and far smaller than the ones on the ISS. And don’t forget that because radiated heat goes up as the fourth power of temperature, raising the temperature of the system by even a small amount raises the radiation emitted by a lot. If you design the system to run hotter you can minimize the size of the radiator. Most chips these days are designed to max out at 100°C to 110°C without lasting damage, although running them at that temperature 24/7 may reduce their lifespan. There will be some sweet spot in the middle.
And it turns out that a Starlink v3 already has a volume somewhat larger than a 48U rack. You talk about launching 250k satellites in order to have 250k GPUs in orbit, but that’s ridiculous. A real compute swarm will be hundreds or thousands of satellites each equivalent to a whole rack of GPUs.
But you’re not wrong to be skeptical. The economics might not work out even if the cooling is easy enough. It’s just that rejecting the idea takes a lot more than back–of–the–envelope calculations.
Everything you wrote is some definition of hard, but all doable. None of this is purely in the territory of 'known' impossible(like FTL travel).
Now different people have different points where they quit when things get hard.
This is true for even everyday things in life. Quitting triggers exist for people at various points in the ladder. The end of ladder and path both exist, its upto you to decide if you wish to continue climbing, or give up and quit.
Your mileage may vary.
More energy will be required than radiation absorbed by a spherical (ish) data center. You'll have massive solar panels piping energy in, and so the temperature would by higher than thermal equilibrium at that distance.
Starlink does not need so much energy as a datacenter.
I don't follow your logic. I mentioned starlink as an example of transistors (and solar panels) in space dealing with radiation.
Well I was talking about heat. But regarding radiation, there is a long history of transistors in space dealing with radiation. But ... there is also a whole science how to deal with making it reliable: answer, expensive redundancy.
And about starlink .. as far as I know the fail quite often but work, because of redundancy. So they get replaced.
If you want to ship GPU's to the orbit, then this surely works somehow, if you are willing to replace them often, which is expensive. Or you shield them, but then you will need to get up heavy shields. In general, of course computers work in space, but it is not cheap.