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Short sellers notch $8.7B profit as SpaceX shares dip to IPO price

reuters.com

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Re: Short sellers notch $8.7B profit as SpaceX shares dip to IPO price

#141

Post by cucumber3732842 »

croes wrote: post #133
nkrisc wrote: post #92

Earlier quoted context omitted.

It’s not an unsolved physics problem. Every satellite in space has to deal with it and even the ISS deals with it by having massive radiator arrays that face perpendicular to the sun. The problem with data centers in space is one of materials science and engineering: how to make radiators large enough and effective enough to cool it while also being economically feasible, both in terms of construction and getting the…

Nobody said space data centers are impossible, it’s just wasteful and ineffective.

Right, but nobody's sure just how wasteful. And at these scales small factors make or break things. That's why it's hard to predict who's bullshitting. A fairly small unforeseen factor here and there adds up to wild financial success or failure over the course of an entire project.

Re: Short sellers notch $8.7B profit as SpaceX shares dip to IPO price

#142

Post by spongebobstoes »

croes wrote: post #130
spongebobstoes wrote: post #127

Earlier quoted context omitted.

radiators about the same size and weight as solar panels will do the trick there is already a h100 in orbit 1GW of compute is a lot in 2026. comparing 100GW of annual compute to SpaceX 2026 goals does not make sense if Starship launch cost predictions are accurate, data centers in space will happen within 10 years

> The numbers are brutal. Starcloud’s own white paper estimates that a two-sided radiator held around 20°C would emit only about 633 watts per square meter, over 1,000 times slower than water cooling of AI chips on Earth. So, a puny 1-megawatt orbital data centre, 1,000 times smaller than the gigawatt scale of hyperscale data centres on Earth, would need about 1,600 square meters of radiator, an area roughly the size…

chips run way hotter than 20C, and radiative cooling scales to the fourth power of temperature. check the math

Re: Short sellers notch $8.7B profit as SpaceX shares dip to IPO price

#143

Post by xtracto »

jacobgold wrote: post #50

I completely understood the idea of Starlink and expected that it would be successful and useful, which it is. I've worked in data centers for decades now, and I am incredibly skeptical of the "data centers in space" sales pitch. It seems like an actual scam. Data centers submerged in the ocean or placed in the desert seem much more promising. But I have only an enthusiast's understanding of rockets and physics, so I…

Too bad the things that really matter don't make "sense" (mostly people talk about economic sense when talking about this).

Increasing the temperature of the earth , and water usage are two things that using Space data centers will excel vs the alternatives. However society has just not been able to price that directly into these huge buildings.

Funny that I agree with EM idea on this, but the reasons are so far away.

Re: Short sellers notch $8.7B profit as SpaceX shares dip to IPO price

#144

Post by AnthonyMouse »

kibwen wrote: post #122
nkrisc wrote: post #92

Earlier quoted context omitted.

It’s not an unsolved physics problem. Every satellite in space has to deal with it and even the ISS deals with it by having massive radiator arrays that face perpendicular to the sun. The problem with data centers in space is one of materials science and engineering: how to make radiators large enough and effective enough to cool it while also being economically feasible, both in terms of construction and getting the…

The physics problem regarding radiator arrays isn't unsolved, but it's not a problem that scales up gracefully. Small-scale radiators could get by via passive cooling, but large-scale radiators need active cooling, and now you need fluid, pipes, and pumps that all represent additional launch mass and points of failure (and the pumps are generating heat of their own, so now you need more radiators...).

Doesn't active cooling provide counterbalancing options to improve efficiency though? For example, use multi-stage heat pumps with different refrigerants so that you can make the hot side very hot and thereby need less mass for radiators.

Re: Short sellers notch $8.7B profit as SpaceX shares dip to IPO price

#145

Post by pjscott »

nijave wrote: post #103
jacobgold wrote: post #73

Earlier quoted context omitted.

Yeah, I have no doubt that it's possible to put GPU servers in space. The Starlink satellites are servers in space. The question is whether it's even remotely profitable to do this for AI training/inference servers.

Training, no. Latency is too high. Inference the latency becomes trivial. Other things, I suspect latency is too high again.

They're going for an orbital height of 600–800 km, or about 2-3 light-milliseconds from Earth's surface. A lot of people think of satellites as being necessarily high-latency because of intuition drawn from satellites in geosynchronous orbit – but those are about 50x farther away from earth and have correspondingly longer ping times.

Re: Short sellers notch $8.7B profit as SpaceX shares dip to IPO price

#146

Post by aeternum »

kibwen wrote: post #122
nkrisc wrote: post #92

Earlier quoted context omitted.

It’s not an unsolved physics problem. Every satellite in space has to deal with it and even the ISS deals with it by having massive radiator arrays that face perpendicular to the sun. The problem with data centers in space is one of materials science and engineering: how to make radiators large enough and effective enough to cool it while also being economically feasible, both in terms of construction and getting the…

The physics problem regarding radiator arrays isn't unsolved, but it's not a problem that scales up gracefully. Small-scale radiators could get by via passive cooling, but large-scale radiators need active cooling, and now you need fluid, pipes, and pumps that all represent additional launch mass and points of failure (and the pumps are generating heat of their own, so now you need more radiators...).

Thermal dissipation scales quartically with T, that's about as graceful as you can get from a physics POV, very few things scale at that rate.

COTs GPUs throttle at about 90-100C but that's because they have plastic parts and solder that melts. Those are relatively easy to eliminate.

We haven't tried much to scale up operating temp.

Re: Short sellers notch $8.7B profit as SpaceX shares dip to IPO price

#147

Post by chris_money202 »

vlovich123 wrote: post #83
chris_money202 wrote: post #57

Earlier quoted context omitted.

Repairability and depreciation are the main problems. A earth data center can be repaired, depreciated, and recycled at EoL recovering some of the costs. SpaceX datacenters are a total write off from the moment they are launched.

The Microsoft design of filling an airtight submersible structure with argon and dropping it to the bottom of the ocean floor is the alternative design - you’re not looking to do repairs but amortize the low cost of failures across the value you extract. The biggest issue with space is not repairability but heat - when you’re in a vacuum the only way to disperse heat is through black body radiation and that’s horribl…

Right, a heat exchange is reusable though on earth and can be recycled across multiple SKUs and thus depreciates longer. In space similar to how you can’t repair you also can’t swap.

Re: Short sellers notch $8.7B profit as SpaceX shares dip to IPO price

#148

Post by Mawr »

eldenring wrote: post #114
metalliqaz wrote: post #106

Earlier quoted context omitted.

> from every perspective but cooling, radiation shielding, and cost/ease of installation. Oh is that all? Those are major data center concerns. Don't forget the biggest one: an ocean-based system could be pulled up and serviced without the need for a human-rated rocket. Oh, and bandwidth/latency. The ONLY benefit of space is that it doesn't require siting a major construction in a town full of angry residents, and it…

Cooling is relatively easy, you just need radiators which are passive, and essentially reduce to a launch cost penalty. You are right that they can't be serviced, but that is missing the point of orbital data centers. The whole point is that you can build hundreds of thousands of these in a factory and launch them in a scalable manner. The power, cooling, etc. comes for "free". In the long run, as the cost of the chi…

> and essentially reduce to a launch cost penalty.

Are you arguing that all this is technically possible or something? The whole point is that the costs would dwarf the gains.

> You are right that they can't be serviced, but that is missing the point of orbital data centers.

Pointing out a downside of something isn't ever "missing the point".

> The whole point is that you can build hundreds of thousands of these in a factory

In an Earth-based factory, right? Am I to understand that we can't build hundreds of thousands of regular Earth-based datacenters in a factory?

> and launch them in a scalable manner.

Wanna bet that launching something to space will always be a few orders of magnitude more expensive than shipping it somewhere across the planet?

> The power, cooling, etc. comes for "free".

Unlike on Earth, where you pay for sunshine? Or is cooling "free" in space but not on Earth? Lol?

> In the long run, as the cost of the chip, launches, etc. goes down, orbital data centers will scale better terrestrial ones.

The costs of the chips will get lower in space than on Earth?

The costs of launches will, again, become cheaper than terrestial transport?

> As a side note, I don't understand why I keep seeing these wrong arguments on HN repeatedly. Like everything mentioned in this thread can easily be fact checked. Radiative cooling is solved, launch costs are going down, so power costs will pay themselves back very quickly, etc.

The question isn't whether this is physically possible, but why you'd want to do it instead of an Earth-based datacenter. It's all downsides basically.

Re: Short sellers notch $8.7B profit as SpaceX shares dip to IPO price

#149

Post by nkrisc »

kibwen wrote: post #122
nkrisc wrote: post #92

Earlier quoted context omitted.

It’s not an unsolved physics problem. Every satellite in space has to deal with it and even the ISS deals with it by having massive radiator arrays that face perpendicular to the sun. The problem with data centers in space is one of materials science and engineering: how to make radiators large enough and effective enough to cool it while also being economically feasible, both in terms of construction and getting the…

The physics problem regarding radiator arrays isn't unsolved, but it's not a problem that scales up gracefully. Small-scale radiators could get by via passive cooling, but large-scale radiators need active cooling, and now you need fluid, pipes, and pumps that all represent additional launch mass and points of failure (and the pumps are generating heat of their own, so now you need more radiators...).

So what’s the unsolved physics problem? Everything you’re describing are engineering challenges.
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