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Comment by dgfl

2 months ago

The existence of starlink proves that this is false. Look at most current pitches, they don’t talk about GW-class monsters anymore. There’s absolutely nothing stopping a 20-30kW satellite bus the size of starlink (or I guess up to 100kW? once starship is available - it’s all about payload fairing diameter) from hosting ~1 rack of compute and antennas. The economics may or may not make sense, we’ll have to see.

There’s very little research work needed to make this happen; it’s all about engineering some satellite buses and having them fly in close formation to get a “data center”. And this group of satellites in sun-synchronous orbit would relay to a comms constellation e.g. starlink itself) and operate as a global scale data center. The heat management and orbital mechanics are all straight forward really.

I've heard this before. A datacenter and a starlink sattelite are not in the same ballpark of power usage and heat dissipation needs. The are orders of magnitude off from each other.

  • The point is that you don’t need to put a whole datacenter into a single satellite. You can put a single rack per satellite and have different racks communicate via antennas, laser links, or perhaps even wires since they’ll be launched in groups of 10-50 anyway. You could also dock them to each other, but that’s not necessarily needed.

    • I don't understand what makes these "datacenters" if they're distributed across satellites with WAN-esque interconnect.

      Are we overloading the term "datacenter"? Or is it not overloaded but somehow able to achieve datacenter-like speeds / (tail) latency even when distributed across satellites?

    • Ok, but then what's the point? How is having a small amount of compute in space useful?

It's worth noting that GPUs have a much higher failure rate than traditional CPUs. Over 10x the failure rate due thermal stress. The amount of heat generated is very different. You can't really replace a GPU in a satellite (at least today?) which would place most of these satellites as space debris in a ~5 year horizon.

  • Usually satellites utilize an older node as newer nodes are easily bit-flipped by radiation. And blocking radiation is heavy.

    AI calcs may handle wrong calculations better than cpus where software will tend to panic.

"Space datacenter" -> overpriced starlink with some shitty edge compute -> "look guys, we built a space datacenter; earnings results to follow" -> number go up.

I don’t think Sun synchronous orbit is possible except in LEO.

LEO is high risk and star link satellites deorbit or burn up all the time. Not good from a capex POV on graphics cards.

How much power could we get out of the fuel required to launch a 20-100kW rack in to space, if we were to burn it on the ground?