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mike_hearn 4 hours ago

But the focus on building giant monolithic datacenters comes from the practicalities of ground based construction. There are huge overheads involved with obtaining permits, grid connections, leveling land, pouring concrete foundations, building roads and increasingly often now, building a power plant on site. So it makes sense to amortize these overheads by building massive facilities, which is why they get so big.

That doesn't mean you need a gigawatt of power before achieving anything useful. For training, maybe, but not for inference which scales horizontally.

With satellites you need an orbital slot and launch time, and I honestly don't know how hard it is to get those, but space is pretty big and the only reasons for denying them would be safety. Once those are obtained done you can make satellite inferencing cubes in a factory and just keep launching them on a cadence.

I also strongly suspect, given some background reading, that radiator tech is very far from optimized. Most stuff we put into space so far just doesn't have big cooling needs, so there wasn't a market for advanced space radiator tech. If now there is, there's probably a lot of low hanging fruit (droplet radiators maybe).

leoedin 2 hours ago | parent | next [-]

But why would you?

Space has some huge downsides:

* Everything is being irradiated all the time. Things need to be radiation hardened or shielded.

* Putting even 1kg into space takes vast amounts of energy. A Falcon 9 burns 260 MJ of fuel per kg into LEO. I imagine the embodied energy in the disposable rocket and liquid oxygen make the total number 2-3x that at least.

* Cooling is a nightmare. The side of the satellite in the sun is very hot, while the side facing space is incredibly cold. No fans or heat sinks - all the heat has to be conducted from the electronics and radiated into space.

* Orbit keeping requires continuous effort. You need some sort of hypergolic rocket, which has the nasty effect of coating all your stuff in horrible corrosive chemicals

* You can't fix anything. Even a tiny failure means writing off the entire system.

* Everything has to be able to operate in a vacuum. No electrolytic capacitors for you!

So I guess the question is - why bother? The only benefit I can think of is very short "days" and "nights" - so you don't need as much solar or as big a battery to power the thing. But that benefit is surely outweighed by the fact you have to blast it all into space? Why not just overbuild the solar and batteries on earth?

Findeton 2 hours ago | parent | next [-]

Maybe they should try to build it in the moon. Difficult, but perhaps not as difficult?

nkrisc an hour ago | parent | next [-]

Sounds more difficult. Not only is the moon further, you also need to use more fuel to land on it and you also have fine, abrasive dust to deal with. There’s no wind of course, but surely material will be stirred up and resettle based on all the landing activity.

And it’s still a vacuum with many of the same cooling issues. I suppose one upside is you could use the moon itself as a heat sink (maybe).

thephyber 2 hours ago | parent | prev | next [-]

Almost none of the parent’s bullet points are solved by building on the Moon instead of in Earth orbit.

The energy demands of getting to the 240k mile Moon are IMMENSE compared to 100 mile orbit.

Ultimately, when comparing the 3 general locations, Earth is still BY FAR the most hospitable and affordable location until some manufacturing innovations drop costs by orders of magnitude. But those manufacturing improvements have to be made in the same jurisdiction that SpaceXAI is trying to avoid building data centers in.

This whole things screams a solution in search of a problem. We have to solve the traditional data center issues (power supply, temperature, hazard resilience, etc) wherever the data centers are, whether on the ground or in space. None of these are solved for the theoretical space data centers, but they are all already solved for terrestrial data centers.

ethbr1 an hour ago | parent [-]

In situ iron, titanium, aluminum?

sdenton4 43 minutes ago | parent | prev | next [-]

The 2.5s round trip communication latency isn't going to be great for chat. (Alongside all the other reasons.)

ahoka an hour ago | parent | prev | next [-]

It has all these problems, plus more.

kakacik an hour ago | parent | prev [-]

Yeah, carrying stuff 380k km and still deploying in vacuum (and super dusty ground) doesn't solve anything but adds cost and overhead. One day maybe, but not these next decades nor probably this century.

wombatpm an hour ago | parent | prev [-]

It would make more sense to develop power beaming technology. Use the knowledge from Starlink constellations to beam solar power via microwaves onto the rooftops of data centers

habinero an hour ago | parent [-]

Why? We have solar panels and fossil fuels at home.

cogman10 3 hours ago | parent | prev | next [-]

> I also strongly suspect, given some background reading, that radiator tech is very far from optimized. Most stuff we put into space so far just doesn't have big cooling needs, so there wasn't a market for advanced space radiator tech. If now there is, there's probably a lot of low hanging fruit (droplet radiators maybe).

You'd be wrong. There's a huge incentive to optimized radiator tech because of things like the international space station and MIR. It's a huge part of the deployment due to life having pretty narrow thermal bands. The added cost to deploy that tech also incentivizes hyper optimization.

Making bigger structures doesn't make that problem easier.

Fun fact, heat pipes were invented by NASA in the 60s to help address this very problem.

zero_bias 3 hours ago | parent | next [-]

ISS and MIR combined are not a "large market". How many radiators they require? Probably a single space dc will demand a whole orders of magnitude more cooling

mike_hearn 3 hours ago | parent | prev [-]

The ISS is a government project that's heading towards EOL, it has no incentive to heavily optimize anything because the people who built it don't get rich by doing so. SpaceX is what optimization looks like, not the ISS.

jeltz 2 hours ago | parent [-]

By the same token SpaceX has no reason to optimize Starship. That is also largely a government project.

b112 an hour ago | parent [-]

It's a private company, is profit motivated, and thus has reason to optimize. That was the parent poster's point.

Starship isn't largely a government project. It was planned a decade before the government was ever involved, they came along later and said "Hey, this even more incredible launch platform you're building? Maybe we can hire SpaceX to launch some things with it?"

Realistically, SpaceX launches far more payload than any government.

habinero 43 minutes ago | parent [-]

Haha no. SpaceX survives entirely on money from the US government. It's always been that way.

thephyber an hour ago | parent | prev [-]

There is a lot of hand waiving away of the orders of magnitude more manufacturing, more launches, and more satellites that have to navigate around each other.

We still don’t have any plan I’ve heard of for avoiding a cascade of space debris when satellites collide and turn into lots of fast moving shrapnel. Yes, space is big, but low Earth orbit is a very tiny subset of all space.

The amount of propulsion satellites have before they become unable to maneuver is relatively small and the more satellite traffic there is, the faster each satellite will exhaust their propulsion gasses.

turtlesdown11 34 minutes ago | parent [-]

>There is a lot of hand waiving away of the orders of magnitude more manufacturing, more launches, and more satellites that have to navigate around each other.

This is exactly like the Boring Company plans to "speed up" boring. Lots of hand waving away decades of commercial boring, sure that their "great minds" can do 10x or 100x better than modern commercial applications. Elon probably said "they could just run the machines faster! I'm brilliant".