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Last time these folks were mentioned on HN, there was a lot of skepticism that this is really possible to do. The issue is cooling: in space, you can't rely on convection or conduction to do passive cooling, so you can only radiate away heat. However, the radiator would need to be several kilometers big to provide enough cooling, and obviously launching such a large object into space would therefore eat up any cost savings from the "free" solar power.

More discussion: https://news.ycombinator.com/item?id=43977188

Maybe this is reductive, but there are times that I'm concerned the only thing keeping me from getting gobs and gobs of startup funds are the facts that I understand basic principles of engineering in space.

I could be wrong and this will be a slam dunk. To me, however, the costs/complexity (Cooling, SRP perturbation, stationkeeping, rendezvous, etc.) far outweigh the benefits of the Cheap as Free (tm) solar power

You've also got the problem of cosmic radiation flipping bits. Your fault tolerant architecture probably mitigates this with redundancy, with the extra servers again eating into the purported advantages of extra solar power. Dealing with the PITA of single event upsets is something developers of edge data processing software in space put up with to avoid the latency issues that data clouds in space introduce
My initial thought was "cooling is going to be a fun challenge, in addition to data transfer, latency, hardware maintenance and all that other fun stuff". It truly feels like one of those, you-have-too-much-money moments.
This is a big thing never shown in sci-fi. For example, those huge torch ships in The Expanse would need gigantic radiators. Even if the drive were upwards of 90% efficient the waste heat would melt the engine and the rest of the ship.

Even the ISS has sizable radiators. The Shuttle had deployable radiators in the form of the bay doors if my memory serves me correctly.

Oddly enough the otherwise dumb Avatar films are among the only ones to show starships with something approaching proper radiators.

There’s no air resistance in space so radiators don’t impact your flight characteristics.

By my back of the envelope calculations, the radiators would be comparable to the solar arrays, probably somewhat smaller and not massively bigger at least.
Their white paper touches on the issue, which seems slightly hand-wavy without much detail on quantification. They could potentially take advantage of heat gradients from deep space and dissipate heat to explore the Seeback effect.
Even beyond cooling, just getting all the hardware up there is extremely costly, and for what benefit over ground based DCs? The cooling is the ongoing problem but the cost of lifting it there obliterates all the other problems, IMO.
Their website pitches it as 16 square km
If the Mass Effect games have taught me anything, it's that heat dissipation in outer space is hard.
They state that in 10 years all data centers will be in outer space. I state that in 10 years we will look back and think this was a ridiculous idea. The meta and maintenance costs, the pollution of sending them to space, the space pollution itself, the outer space radiation, the extra redundant error correction needed*,* and much more all speak against this. Why not throw that trillion dollars into optical computing chip research? Why not create better sustainable methods here on earth*?* We could run a single data center down here, or pay a million times moreto do this in space. The argument that we are polluting Earth down here is very weak. Yes, we do, but why on earth do we then not invest more in research for solving these problems*?* There are startups out there that will one day solve these issues. And then space data centers will be something for the Star Trek age, which humanity will probably never achieve.
> In 10 years, nearly all new data centers will be being built in outer space,” Johnston predicts.

Can I bet on the contrary odds? Could throw down my whole retirement with confidence

One of the selling points they mention is that they won't need to use any fresh water for cooling.

My understanding was that water-demands on Earth were an overblown issue and minuscule when compared to other uses of fresh water such as watering one acre of farmland.

Not to mention, "used" water is just "warm" water that can then be used again for other purposes.

So are they perpetuating a myth here? Or is water use a bigger issue than I thought?

>Starcloud’s space-based data centers can use the vacuum of deep space as an infinite heat sink.

The famously heat conductive vacuum...

Someone fedex a vacuum flask full of hot coffee to nvidia HQ with an explanatory note.

Shameful to see this on Nvidia's site. They have real engineers and business prowess. This is really shaking my assumptions about the company.
Altman: has stake in nuclear power and AI companies

Also Altman: Let's build gigawatts of nuclear for AI

Musk: has stake in space and AI companies

Also Musk: Let's build AI datacenters in space

Apart from getting 16 sq. km of solar arrays and radiators into orbit - and without jumping to conclusions about whether this is a borderline scam - I can imagine 2 obvious showstoppers:

1) Space debris. This is proposal is several orders of magnitude larger than the biggest things in near-Earth orbits. Thus equally many orders more likely to be hit by, and create, space debris

2) Heat transport - this isn't my home turf, but I can't imagine building something lightweight enough to be launched, yet also capable of transferring enough heat away from the 5 GW core, without it melting/breaking

It's been a while since I read their whitepaper, but I don't recall either of those points being addressed.

We've officially lost the plot, we will now ship our AI data centers to ~space~ ... This will not work with modern technology.

The sun will be eclipsed by earth many times per day, requiring you to either shift all workloads or add substantial UPS weight. The radiator grid you need to cool 125kw is something like 16x the size of the entire data center.

I watched this video last week that went into 3 different scenarios, it's a good watch.

https://www.youtube.com/watch?v=JAcR7kqOb3o

Their numbers strike me as very optimistic:

    *Table 1. Cost comparison of a single 40 MW cluster operated for 10 years in space vs on land.*

    | Cost Item                     | Terrestrial                     | Space
    |:------------------------------|:--------------------------------|:----------------
    | Energy (10 years)             | $140m @ $0.04 per kWh           | $2m cost of solar array
    | Launch                        | None                            | $5m (single launch of compute module, solar & radiators)
    | Cooling (chiller energy cost) | $7m @ 5% of overall power usage | More efficient cooling architecture taking advantage of higher ΔT in space
    | Water usage                   | 1.7m tons @ 0.5L/kWh            | Not required
    | Enclosure (Sat. Bus/Building) | Approximately equivalent cost   | Approximately equivalent cost
    | Backup power supply           | $20m                            | Not required
    | All other DC hardware         | Approximately equivalent cost   | Approximately equivalent cost
    | Radiation shielding           | Not required                    | $1.2m @ 1 kg of shielding per kW of compute and $30/kg launch cost
    | Cost Balance                  | $167m                           | $8.2m
Source: Page 4 of their whitepaper https://starcloudinc.github.io/wp.pdf
Actual engineering question. How large can you scale a cooling system in space? And I mean say from radial central point. Surely at some point it just doesn't work anymore. Or you spend more energy to get energy to point where you can radiate it away than you can radiate.
So many questions, like how would you protect from bit flips, damage to circuits. "10x lower energy costs and reduce the need for energy consumption on Earth." I am not sure if we need a rocket scientist to calculate the energy costs of manufacturing and sending a rocket to outer space versus putting that fuel into a generator and just letting it run. What happens when the servers need to retire due to some unpatchable bug
> “In space, you get almost unlimited, low-cost renewable energy,”

Wouldn't you know, you COULD get the same energy here too.

So many questions to be asked, I don't know where to start. What's the upside of bunching up all the servers into a single megastructure rather than separate satellites?
The rate of radiative cooling scales proportionally to (T^4-Tenv^4) which approximates to just T^4 in space (Tenv = 3K). The hotter they can run it, the smaller heatsinks they need; for every doubling of temperature, the heatsink area can be reduced by a factor of 16. Also, it might be possible to boost the output temperature, e.g. with a chemical heat pump for even smaller heat sinks.
How is a multiple square-kilometer radiator not just an inevitable Kessler syndrome disaster?

Edit: Some back of the envelope calculation suggests that the total cross-sectional area of all man-made orbiting satellites is around 55000 m^2. Just one 4km x 4km = 1600000m^2 starcloud would represent an increase by a factor of about 300. That's insane.

“The only cost on the environment will be on the launch, then there will be 10x carbon-dioxide savings over the life of the data center”

And how long is that life exactly? There is zero chance this is a net positive for carbon emissions, much less a remotely economical way to build or operate datacenters.

I'm by no means closer or educated enough on astrophysics or anything to do with space. Hence I have a very "commoner" question:

- asteroids? Debris? It's there even any risk of anything significantly big to be damaged by something flying by?

"About once a year, an automobile-sized asteroid hits Earth’s atmosphere, creates an impressive fireball, and burns up before reaching the surface."

I assume a good old "Prius" might have opinions about such construction of it flies through it.

But I guess "space is big", risks are low?

https://www.nasa.gov/solar-system/asteroids/asteroid-fast-fa...

You'll never be able to do maintenance or upgrade these things. The up front cost seems extremely high given the risk of hardware failure or obselecence at data center scales.
> Starcloud plans to build a 5-gigawatt orbital data center with super-large solar and cooling panels approximately 4 kilometers in width and length.

That is...very, very large.

“The only energy is the launch”, that’s false.

Energy went into mining, extracting, refining, transporting all the raw materials needed to make these chips.

This is typical tech industry green washing as the industry fails to accept its destructive influence on the planet.

We need practical solutions that help reduce consumption and waste and actually address the issues. We don’t always need more we need to find a way to use less.

I've barely started reading the post, but

> “In space, you get almost unlimited, low-cost renewable energy”

Low cost???????? Sending a solar array into space would probably rank among the most expensive forms of energy production.

> Starcloud’s space-based data centers can use the vacuum of deep space as an infinite heat sink.

Well, good luck getting the heat out first. I hope you planned for some big radiators to go along your 5GW solar array.

I have yet to meet a hardware engineer who thinks this is a good idea. I'm REALLY struggling to see benefits.
Oh, cool... I have only one question (that is not cool at all): how are they about to exhaust 5GW of waste heat?
I though that refrigerating things in space was using a lot of energy because heat cannot dissipate in the void of space.

Moreover, why are the energy cost 10x lower when in space you have unlimited access to sun power? Is it the cost of building the energy production infrastructure ?

It’s more of a building the solution first and then look for the problem because why the heck not.
If this math added up, wouldn't solar panels and radiators on earth solve the same problem?
Would it be more cost effective and more sustainable to heavily invest in graphene semiconductors than space-based datacenters? Is that a false dilemma?

Aren't there advantages to fabricating GO Graphene Oxide and CNT Carbon Nanotubes in microgravity?

So when a storage device or a GPU burns out, how do you replace it?

Fly an astronaut to space..?

I could see gov imaging satellites with a direct encrypted laser communications to GPU’s in orbit being attractive. Images processing, movement pattern analysis, multi spectral, and as they mentioned radar.
This is a super basic question, how do they prevent the panels from being hit my space debris or rocks, floaties etc?

Is it just that within its orbit there are next to no objects it could collide with, even small ones?

Replacing faulty nodes or equipment in space seems totally reasonable... It's not like getting faulty drives replaced in my datacenter racks don't already take weeks/months...
I have had people point out that building a Dyson sphere is pretty much a dumb idea, and there's no concievable reason why we would build one even if we could.

Now we have one - venture capital.

Even if the some how solved the cooling problem others mentioned.

What happens when this data center becomes obsolete? we've just got a 4km wide piece of junk floating above earth now?

I still like Keith Lofstrom's Server Sky concept.

http://server-sky.com/ServerSky

We have officially "jumped the shark." If this had been posted on April 1st I would have laughed at this and said "great joke guys."
This cannot possibly end well (flipped bits, maintenance, cooling).

If they fulfill their promise within 10 years I'll change careers to kiwi farming. I promise.

Thats a ridiculous amount of solar pannels to send up. I don't really think this is going to work/be viable
Would this not only work if there are solar arrays always catching the sun while the gpus are never in the sun?