Thread

1. zactato · 1790267254 · focus · HN ↗

   How are they solving the heat dissipation issues?

   1. GMoromisato · 1790270501 · focus · HN ↗

      Please stop with this argument. This is one of the easiest problems to solve. Heat dissipation requires a radiator, which is just a dumb hunk of metal. All you need is a cheap way to launch mass to orbit, which is exactly what SpaceX (and Chinese companies) are doing.

      The only valid argument against data centers in space is the economic cost. If the per megatoken price for space datacenters is higher than terrestrial, then this won't work.

      But the price for terrestrial datacenters keeps going up and technology keeps dropping the price of space-based.

      1. legohead · 1790274545 · focus · HN ↗

         and yet notice how the cooling video / section was the only one they didn't have a solution for... just saying "radiator" doesn't make sense - the radiator heats up too. it's how you get rid of the heat, not where you put it.

         1. GMoromisato · 1790277423 · focus · HN ↗

            Huh? Radiators are known technology. They have them on ISS; they have them on every Starlink satellite. This isn't like warp drive or antigravity.

            Moreover, you can easily calculate how big of a radiator you need for a given power level and temperature. You can use the Stefan–Boltzmann law:

              A ~ (1000 P) / (2 e k T^4)
            

            Where

              A is the radiator area in square meters
              P is the power in kilowatts
              e is emissivity (usually 0.9)
              k is the constant 5.67e-8
            

            For a 1 kW test like Googles, you just need 1 square meter of radiators (assuming two-sided).

            For SpaceX's 175 kW satellites, they will need ~170 square meters of radiators.

            None of this is impossible or even difficult to calculate. That's why I think this is the laziest argument against space data centers. There are so many other more reasonable arguments (like whether they will be economically competitive) but people love to latch on to this one for some reason.

            1. legohead · 1790282880 · focus · HN ↗

               sure, the physics is solved: we know how radiators work, and we can calculate the area needed, blah blah. but we haven't put sustained-AI-computer systems into space yet - heat is a genuine concern, and personally I'm curious if they are developing something beyond simple radiators. if a ~1m^2 radiator works, great. but if the current test can only run the TPUs for ~15-minute bursts before it has to stop and dump heat, this issue isn't exactly "solved" in my book.

               1. GMoromisato · 1790283482 · focus · HN ↗

                  I don't understand your argument. Sounds like you're saying, "In theory it should work, but what if there are space pixies that keep rebooting the TPUs? What do we do then?"

                  The 15-minute figure is what they currently designed for because they have mass constraints. If they wanted a different figure (like forever) they could do it with a larger radiator.

                  As you said, the physics is solved! We know exactly how much heat a surface radiates in space--there is literally an equation for it. We know how to cool stuff in space. Will the price be low enough to make a profit? That's the real question. But stop worrying about cooling in space.

                  1. tensor · 1790293024 · focus · HN ↗

                     No one thinks we don't know how to cool things in space. Everyone is saying that it's not feasible because you'd have to put too much mass up. Stop derailing the conversation please.

                     If you have something useful to contribute regarding how to actually reasonably put up enough mass to make this remotely a feasible idea then please contribute. We have the technology to prevent global warming, and doing that is far easier than this, and yet even that is apparently not feasible for humanity.

                     1. GMoromisato · 1790295038 · focus · HN ↗

                        I honestly don't get that. The current SpaceX design is for a ~4 ton satellite with 160 m^2 radiator with peak 250 kW output. You can launch 25 of those satellites on a single Starship launch. 160 Starship launches and you get 4,000 satellites with peak 1 GW compute.

                        What's unfeasible about that? SpaceX has already launched 10,000 Starlink satellites. Falcon 9 launches 150 times per year.

Unofficial Hacker News client; not affiliated with Y Combinator.