More discussion: >>43977188
Even the ISS has sizable radiators. The Shuttle had deployable radiators in the form of the bay doors if my memory serves me correctly.
Oddly enough the otherwise dumb Avatar films are among the only ones to show starships with something approaching proper radiators.
There’s no air resistance in space so radiators don’t impact your flight characteristics.
Wonder if that would be less impactful than how ever many rockets they'll need to send up, plus you could, ya know, ~drive~ bike to a failed machine.
So, it's the solar/cooling panels that make up that space, not the data centre per se.
> Next [after loading the computers with on-orbit software] we opened the payload bay doors. The inside of those doors contained radiators used to dump the heat generated by our electronics into space. If they failed to open, we’d have only a couple hours to get Discovery back on Earth before she fried her brains. But both doors swung open as planned, another milestone passed.
Here on earth we are surrounded by many molecules, that are not so cold, but colder than us and together they can take a lot of our excess heat energy away.
Stuff in space does.
I imagine it's the same reason James Cameron is a world expert on submersibles - the guy picks individual topics in his movies to really get right.
I'm pretty sure it was that series that also described https://en.wikipedia.org/wiki/Liquid_droplet_radiator , with the side effects of different ships having very distinct heat patterns because of their radiator patterns. And that if a ship ever had to make a turn while they were active, big glowing arcs of slowly-cooling droplets would be flung out into space and leave a kind of heat plume.
This prompted my curiosity. None of the following contradicts the thrust of your message, but I thought the nuance is interesting to share.
Interstellar space isn't a vacuum. Space is mostly empty compared to Earthly standards, but it still contains gas (mostly hydrogen and helium), dust, radiation, magnetic fields, and quantum activity.
The emptiest regions are incredibly sparse, but not completely empty. Even in a perfect vacuum, quantum mechanics predicst that particle-antiparticle pairs constantly pop in and out of existence, so empty space can be said to be buzzing with tiny fluctuations.
> Space is not cold. It has no real value for temperature. Stuff in space does.
The cosmic microwave background radiation, the left-over energy from the Big Bang, sets a baseline temperature of about 2.7K (-270°C), just above absolute zero.
Temperature depends on particle collisions, and since space isn't a vacuum, just incredibly sparse, one can talk about the temperature of space, but you're right that what is typically more relevant is the temperature of "specific" objects.
> Because caches hold the most recent and most relevant data to the current processing, it is critical that this data be accurate. To enable this, AMD has designed EPYC with multiple tiers of cache protection. The level 1 data cache includes SEC-DED ECC, which can detect two-bit errors and correct single-bit errors. Through parity and retry, L1 data cache tag errors and L1 instruction cache errors are automatically corrected. The L2 and L3 caches are extended even further with the ability to correct double errors and detect triple errors.
1) The atmosphere attenuates sunlight (even when it's not cloudy)
2) The solar array in orbit can pivot to face the sun all the time.
3) While most orbits will go into earth's shadow some of the time, on average they'll be in sunlight more of the time than a typical point on the surface.
For solar panels:
Assuming area of 1000 square meters (30m x 30m square), solar irradiance of 1 kW/m^2, efficiency of 0.2. As a result power is 200 kW.
For radiators:
Stefan-Boltzmann constant 6E-8, temperature difference of 300 K, emissivity of one, we get total radiator power 1000 x 6E-8 x 300^4 = 486 kW.
The radiator number is bigger so the radiator could be smaller than the solar panels and could still radiate away all the heat. With caveats.
Temperature difference in the radiator is the biggest open question, and the design is very sensitive to that. Say if your chips run at 70 C (340 K), what is the cool temperature needed to cool down to, what is the assumed solar and earth flux hitting the radiator, depends on geometry and so on. And then in reality part of the radiator is cooler and radiates way less, so most of the energy is radiated from the hot part. How low do you need to get the cool end temperature to, in order to not fry your chips? I guess you could run at very high flow rates and small temperature deltas to minimize radiator size but then rest of the system becomes heavier.
I'm skeptical that it makes any economic sense to put a datacenter in orbit, but the focus on the radiators in the last discussion was odd - if you can make the power generation work, you can make the heat dissipation work.
I could be wrong and this will be a slam dunk. To me, however, the costs/complexity (Cooling, SRP perturbation, stationkeeping, rendezvous, etc.) far outweigh the benefits of the Cheap as Free (tm) solar power
The difference between a criminal and a law-abiding citizen isn't that the citizen knows that crimes are wrong, it's that the citizen cares that crimes are wrong and the criminal doesn't.
Any data center that isn't generating massive heat is a waste of our time.
And no, JWST is not doing industrial scale cooling.
Why is this exclusive to space? If you're powering datacenters on solar, one would think covering the Sahara or other large desert in datacenters would be easier than launching them into space. Renewable energy is just as plentiful and free there, you can connect it to the rest of the world with multiple TB/s of fiber links, and the construction/maintainence costs would be a few orders of magnitude less.
If it not i want dibs on it.
> and even the nuclear decay (due to practical considerations the latter, as well as the atmospheric noise, is not viable except for fairly restricted applications or online distribution services)
https://starcloudinc.github.io/wp.pdf
Your thinking seems more risk averse, which is similar to myself. However that doesn't mean that without the business drivers these types of things can't happen if enough attention is given too it. Costs are often because we're comparing one thing which has significant efficiencies built into the supply chain, vs something that doesn't, which by virtue drives up the cost. Perhaps Nvidia have money to burn on trying something.
If you think of a big ball of droplet mist. From the point of view of a droplet in the center, it gets heat radiation from all the droplets around it. It can only radiate heat to black sky it sees, and it might be none, it's "sky" is just filled by other hot droplets. So it doesn't cool at all.
The total power radiated can't exceed the proportion to the macro surface area with tricks.
These plans are so much larger than anything built so far that they're scifi.