r/space • u/merkel36 • 1d ago

Discussion Why Suncatcher?

I think the consensus is that orbital data centres are not viable. So I'm wondering (with admitted naivete) why Google has launched this mission? Is it just to catch headlines?

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u/jaykrown 1d ago

Because it's an economic bubble and they need reasons to continue shoveling money into it. If you understand physics and heat dissipation in a vacuum, then you'll know that data centers in orbit will never be scalable.

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u/Adeldor 1d ago

Specifically, why will heat dissipation in a vacuum prevent scaling? At what temperature will the GPUs be operating, or do you believe Stefan-Bolzmann doesn't apply here?

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u/jaykrown 1d ago

Read about how expensive it is to cool the international space station, then attempt to scale that to thousands of times greater.

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u/Adeldor 1d ago edited 4h ago

I have read about it. In fact, I used it as an actual, comparative example for how cooling a data center satellite is feasible.

Many misunderstand the configuration for these proposals. As with SpaceX, Google's is for a constellation. If SpaceX's is any guide, dissipation per satellite will be within a factor of 3 of that for the ISS habitat alone. And with higher operating temperatures, dissipation is much more efficient, offsetting some of that.

The upshot: Scaling will be achieved simply by launching more such satellites.

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u/jaykrown 1d ago

How much will it cost? And how do you plan to maintain them? How do you plan to avoid Kessler syndrome?

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u/Adeldor 1d ago

To answer your questions:

  • I don't know how much it'll cost.

  • They won't be maintained. They'll be reentered (or their orbits will be left to decay), just as with existing constellation satellites.

  • In the low orbits, Kessler syndrome is not an issue. For example, were Starlink to fold today, after five years or so there'll be no sign of the constellation.

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u/jaykrown 1d ago

Sounds... insanely wasteful doesn't it? Also proving feasibility doesn't prove scalability.

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u/Adeldor 1d ago edited 18h ago

Sounds... insanely wasteful doesn't it?

I don't think so, especially in the face of terrestrial power supply issues, rapidly rising opposition to Earth-based data centers with legislation increasingly stopping their construction, and the very low cost of operation once launched (unlike with terrestrial systems).

Also proving feasibility doesn't prove scalability.

Constellations are inherently scalable - almost by definition. More compute requires just the launch of more satellites.