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notahackertoday at 9:42 AM1 replyview on HN

The point is that they're absolutely not in isolation from other challenges because designing something to radiate heat at maximum possible radiative cooling efficiency is not considered to be a problem, solving the unit economics of launching the required radiator tonnage and burning 100 tonnes of rocket fuel to per tonne launched that's the problem. Cutting edge stuff like in-space refuelling and modular in-space reassembly and patient capital are crucial to making those work because the radiators aren't getting beyond 100% radiative cooling efficiency however well designed they are.

Optimizing for local circumstances is a benefit to doing things on earth: if having a production line and the ability to plug into wherever energy happens to be cheapest was better we'd all be sticking inference chips in shipping containers and not worrying about HVACs being relatively inefficient at cooling.


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pveierlandtoday at 10:04 AM

> The point is that they're absolutely not in isolation from other challenges because designing something to radiate heat at maximum possible radiative cooling efficiency is not considered to be a problem, solving the unit economics of launching the required radiators tonnage and burning 100 tonnes of rocket fuel to per tonne launched that's the problem.

I was pointing out relative coupling, not absolute coupling. The coupling between the different design decisions involved in Terafab or Starship seems far greater as there are so many design levels to unite jointly - while figuring out the structural and thermal design of these satellites appears to be something that to a greater degree can be resolved with less design constrained coupling - i.e. making it more feasible to figure out with a lower number of people.

> Optimizing for local circumstances is a benefit to doing things on earth: if having a production line and the ability to plug into wherever energy happens to be cheapest was better we'd all be sticking inference chips in shipping containers and not worrying about HVACs being relatively inefficient at cooling.

I did not reference energy cost directly. In many countries there are year-long lines for data centers to even be allowed to connect to the grid, which is why many also resort to local gas turbine power plants etc. Having a cost effective (the unknown is if/when this becomes possible) method of deploying large units of compute without dealing with this power access issue - zoning issues - local policies etc - appears to be one of the large attractions to this endeavor, in addition to being able to avoid longer term scaling issues. Inference sticks are not cost effective at scale now and that does not seem to be on the horizon. Space based compute however seems to be a more open question depending on your timeline.

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