[gpt5]

I'm confused about the level of conversation here. Can we actually run the math on heat dissipation and feasibility?

A Starlink satellite uses about 5K Watts of solar power. It needs to dissipate around that amount (+ the sun power on it) just to operate. There are around 10K starlink satellites already in orbit, which means that the Starlink constellation is already effectively equivalent to a 50 Mega-watt (in a rough, back of the envelope feasibility way).

Isn't 50MW already by itself equivalent to the energy consumption of a typical hyperscaler cloud?

Why is starlink possible and other computations are not? Starlink is also already financially viable. Wouldn't it also become significantly cheaper as we improve our orbital launch vehicles?

[hirsin]

Simply put no, 50MW is not the typical hyperscaler cloud size. It's not even the typical single datacenter size.

A single AI rack consumes 60kW, and there is apparently a single DC that alone consumes 650MW.

When Microsoft puts in a DC, the machines are done in units of a "stamp", ie a couple racks together. These aren't scaled by dollar or sqft, but by the MW.

And on top of that... That's a bunch of satellites not even trying to crunch data at top speed. No where near the right order of magnitude.

[pera]

New GPU dense racks are going up to 300kW, but I believe the normal at moment for hyperscalers is somewhere around ~150kW, can someone confirm?

The energy demand of these DCs is monstrous, I seriously can't imagine something similar being deployed in orbit...

[stonogo]

Most of the OEMs are past 300kW racks, planning on 600kW racks within a year or two, with realistic plans to hit a megawatt

[synctext]

Could this be about bypassing government regulation and taxation? Silkroad only needed a tiny server, not 150kW.

The Outer Space Treaty (1967) has a loophole. If you launch from international waters (planned by SpaceX) and the equipment is not owned by a US-company or other legal entity there is significant legal ambiguity. This is Dogecoin with AI. Exploiting this accountability gap and creating a Grok AI plus free-speech platform in space sounds like a typical Elon endeavour.

[Someone]

For the sake of an argument, let’s assume "The Outer Space Treaty (1967) has a loophole. If you launch from international waters (planned by SpaceX) and the equipment is not owned by a US-company or other legal entity there is significant legal ambiguity” is 100% true.

To use that loophole, the rockets launched by SpaceX would have to be “not owned by a US-company”. Do you think the US government would allow that to happen?

[JoBrad]

Looks like their ability to stop unauthorized launches is civil action.

https://spacenews.com/faa-fines-spacex-for-launch-license-vi...

[synctext]

New info now online. Elon Musk has now confirmed it is about getting regulatory permission for solar panel deployment. These regulation stop deployment at scale. Its cheaper in the future in space (prediction: in 36 months).

He was asked directly during interview: is this a regulatory play?

https://youtu.be/BYXbuik3dgA?t=120

[inglor_cz]

You cannot escape national regulations like that, at least until a maritime-like situation develops, where rockets will be registered in Liberia for a few dollars and Liberia will not even pretend to care what they are doing.

It may happen one day, but we are very, very far from that. As of now, big countries watch their space corporations very closely and won't let them do this.

Nevertheless, as an American, you can escape state and regional authorities this way. IIRC The Californian Coastal Commission voted against expansion of SpaceX activities from Vandenberg [1], and even in Texas, which is more SpaceX-friendly, there are still regulations to comply with.

If you launch from international waters, these lower authority tiers do not apply.

[1] https://www.latimes.com/business/story/2025-08-14/california...

[9dev]

Untrue. Responsible for any spacefaring vessel is in all cases the state the entity operating the vessel is registered in. If it's not SpaceX directly but a shell company in Ecuador carrying out the launch, Ecuador will be completely responsible for anything happening with and around the vessel, period. There are no loopholes in this system.

[habinero]

No. There is no "one weird trick" when it comes to regulation. The company is based in the US, therefore you just go after that.

Anyway, promising some fantasy and never delivering is definitely a typical Elon endeavor.

[Schlagbohrer]

This could simply be done by hosting in the Tor hidden service cloud. Accessing illegal material hosted on a satellite is still exactly as risky for the user (if the user is on earth) as accessing that same illegal material through the Tor network, but hosting it through the Tor network can be done for 1/1000th the cost compared to an orbital solution.

So there's no regulatory or tax benefit to hosting in space.

[zbentley]

In addition to all the sibling comments explaining why this wouldn't work, the money's not there.

A grift the size of Dogecoin, or the size of "free speech" enthusiast computing, or even the size of the criminal enterprises that run on the dark web, is tiny in comparison to the footer cost and upkeep of a datacenter in space. It'd also need to be funded by investments (since criminal funds and crypto assets are quite famously not available in up-front volumes for a huge enterprise), which implies a market presence in some country's economy, which implies regulators and risk management, and so on.

[jacquesm]

You misspelled 'hate speech'.

[tensor]

How much of that power is radiated as the radio waves it sends?

[hirsin]

Good point - the comms satellites are not even "keeping" some of the energy, while a DC would. I _am_ now curious about the connection between bandwidth and wattage, but I'm willing to bet that less than 1% of the total energy dissipation on one of these DC satellites would be in the form of satellite-to-earth broadcast (keeping in mind that s2s broadcast would presumably be something of a wash).

[adrian_b]

I am willing to bet that more than 10% of the electrical energy consumed by the satellite is converted into transmitted microwaves.

There must be many power consumers in the satellite, e.g. radio receivers, lasers, computers and motors, where the consumed energy eventually is converted into heat, but the radio transmitter of a communication satellite must take a big fraction of the average consumed power.

The radio transmitter itself has a great efficiency, much greater than 50%, possibly greater than 90%, so only a small fraction of the electrical power consumed by the transmitter is converted into heat and most is radiated in the microwave signal that goes to Earth's surface.

[tullianus]

Unfortunately this is not the case. The amplifiers on the transmit-side phased arrays are about 10% efficient (perhaps 12% on a good day), but the amps represent only ~half the power consumption of the transmit phased arrays. The beamformers and processors are 0% efficient. The receive-side phased arrays are of course 0% efficient as well.

[klaff]

I'm curious. I think the whole thing (space-based compute) is infeasible and stupid for a bunch of reasons, but even a class-A amplifier has a theoretical limit of 50% efficiency, and I thought we used class-C amplifiers (with practical efficiencies above 50%) in FM/FSK/etc. applications in which amplitude distortion can be filtered away. What makes these systems be down at 10%?

[mlyle]

I doubt half the power is to the transmitter, and radio efficiency is poor -- 20% might be a good starting point.

[synctext]

Is the SpaceX thin-foil cooling based on graphene real? Can experts check this out?

"SmartIR’s graphene-based radiator launches on SpaceX Falcon 9" [1]. This could be the magic behind this bet on heat radiation through exotic material. Lot of blog posts say impossible, expensive, stock pump, etc. Could this be the underlying technology breakthrough? Along with avoiding complex self-assembly in space through decentralization (1 million AI constellation, laser-grid comms).

[1] https://www.graphene-info.com/smartir-s-graphene-based-radia...

[ajnin]

This coating looks like it can selectively make parts of the satellite radiators or insulators, as to regulate temperature. But I don't think it can change the fundamental physics of radiating unwanted heat and that you can't do better than black body radiation.

[synctext]

Indeed, graphene seems capable of .99 of black body radiation limit.

Quote: "emissivity higher than 0.99 over a wide range of wavelengths". Article title "Perfect blackbody radiation from a graphene nanostructure" [1]. So several rolls of 10 x 50 meters graphene-coated aluminium foil could have significant cooling capability. No science-fiction needed anymore (see the 4km x 4km NVIDIA fantasy)

[1] https://opg.optica.org/oe/fulltext.cfm?uri=oe-21-25-30964

[PunchyHamster]

Entirely depends on band, at 10GHz more like 40%, at lower frequencies more, for example FM band can even go to 70%

[mlyle]

If you need linearity for spectral efficiency, you pay for it.

30% power added efficiency is the state of the art up in Ku band if you need a low compression budget. And it's important to note that this doesn't include the substantial power spent in modulation of complex signals or the power conversion, etc, before the transmitter. Or, the power lost in the connection to the antenna and its matching-- can easily exceed 2dB.

https://www.mdpi.com/2072-666X/15/11/1381

[adgjlsfhk1]

the majority is likely in radio waves and the inter satellite laser communication

[hdgvhicv]

Inter sat comms cancels out - every kw sent by one sat is received by another.

[mlyle]

It doesn't, because the beams are not so tight that they all fall on the target satellite, and not all of that is absorbed :P

[nosianu]

The radio receiver and transmitter are additional hardware and energy consumption. They add to the heat, not subtract from it.

[jeltz]

I think you missed the point. If you have a 100 MW communicstion satellite and a 100 MW compute satellite those are very different beasts. The first might send 50% of the energy away as radio communication making it effectively a 50 MW satellitefor cooling purposes.

[habinero]

No, they didn't. You can't "send away" thermal energy via radio waves. At the temperatures we're talking about, thermal energy is in the infrared. That's blackbody radiation.

[adrian_b]

You missed the point.

Nobody describes a satellite by specifying the amount of heat that it produces, but by the amount of electrical energy that it consumes.

In a communication satellite, a large fraction of the consumed electrical energy goes into the radio transmitter. Radio transmitters are very efficient and most of the consumed power is emitted as radio waves and only a very small part is converted into heat, which must be handled by the cooling system.

So in any communication satellite, a significant fraction of the consumed energy does not become heat.

[mortehu]

Your answer makes it seem like you too missed the point. If a Starlink sends a 1000W signal to Earth, that is 1000W of power that does not heat the satellite.

[mike_hearn]

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]

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?

[elihu]

The main reason is that generating energy in space is very cheap and easy due to how ridiculously effective solar panels are.

Someone mentioned in the comments on a similar article that sun synchronous orbits are a thing. This was a new one to me. Apparently there's a trick that takes advantage of the Earth not being a perfect sphere to cause an orbit to precess at the right rate that it matches the Earth's orbit around the sun. So, you can put a satellite into a low-Earth orbit that has continuous sunlight.

https://en.wikipedia.org/wiki/Sun-synchronous_orbit

Is this worth all the cost and complexity of lobbing a bunch of data centers into orbit? I have no idea. If electricity costs are what's dominating the datacenter costs that AI companies are currently paying, then I'm willing to at least concede that it might be plausible.

If I were being asked to invest in this scheme, I would want to hear a convincing argument why just deploying more solar panels and batteries on Earth to get cheap power isn't a better solution. But since it's not my money, then if Elon is convinced that this is a great idea then he's welcome to prove that he (or more importantly, the people who work for him) have actually got this figured out.

[leoedin]

Let's assume your space solar panel is always in sun - so 8760 kWh per year from 1kWp.

In Spain, 1kWp of solar can expect to generate about 1800 kWh per year. There's a complication because seasonal difference is quite large - if we assume worst case generation (ie what happens in December), we get more like 65% of that, or 1170 kWh per year.

That means we need to overbuild our solar generation by about 7.5x to get the same amount of generation per year. Or 7.5kWp.

We then need some storage, because that generation shuts off at night. In December in Madrid the shortest day is about 9 hours, so we need 15 hours of storage. Assuming a 1kW load, that means 15kWh.

European wholesale solar panels are about €0.1/W - €100/kW. So our 7.5kWp is €750. A conservative estimate for batteries is €100/kWh. So our 15kWh is €1500. There's obviously other costs - inverters etc. But perhaps the total hardware cost is €3k for 1kW of off-grid solar.

A communications satellite like the Eurostar Neo satellite has a payload power of 22 kW and a launch mass of 4,500 kg. Assuming that's a reasonable assumption, that means about 204kg per kW. Current SpaceX launch costs are circa $1500 per kg - but they're targeting $100/kg or lower. That would give a launch cost of between $300k and $20k per kW of satellite power. That doesn't include the actual cost of the satellite itself - just the launch.

I just don't see how it will make sense for a long time. Even if SpaceX manage to drastically lower launch costs. Battery and solar costs have also been plummeting.

https://www.spaceconnectonline.com.au/manufacturing/4751-air...

https://www.nextbigfuture.com/2025/01/spacex-starship-roadma...

[mike_hearn]

Thanks for the interesting calculations.

Is it reasonable to use Neo as a baseline? Modern Starlink satellites can weigh 800kg, or less than 20% of Neo. I see discussions suggesting they generate ~73kw for that mass. I guess because they aren't trying to blanket an entire continent in signal? Or, why are they so much more efficient than Neo?

Interestingly the idea of doing compute in space isn't a new one, it came up a few years ago pre-ChatGPT amongst people discussing the v2 satellite:

https://forum.nasaspaceflight.com/index.php?topic=58374.msg2...

Still, you make good points. Even if you assume much lighter satellites, the GPUs alone are very heavy. 700kg or so for a rack. Just the payload would be as heavy as the entire Starlink satellite.

[blastro]

Kind of a scary thought - a DC in space can't be stopped by protests or regulation

[elihu]

That could be one reason they want to do it. Maybe by using data from Palantir or harvested from Elon's work with DOGE, along with twitter user data and whatever else they can get, they want their AI to be the all-seeing eye of Sauron. (Which isn't too far from what the whole ad-tech industry is about in the first place.) Or they want to make sexually explicit deepfakes of everyone Elon doesn't like. Or they want to flood the internet with AI generated right-wing propaganda.

[andyjohnson0]

> So I guess the question is - why bother?

This is a Musk escapade, so my guess would be extraterritoriality and absence of jurisdiction.

[UltraSane]

No. With Musk it is always about inflating his share prices.

[fpoling]

If one kilogram of stuff consumes just 100Wt, then in one month it consumes about 300 MJ. So as long as things works for a year or more energy cost to put them into orbit becomes irrelevant.

To keep things in orbit ion thrusters work nicely and require just inert gases to keep them functioning. Plus on a low Earth orbit there are suggestions that a ramjet that capture few atoms of atmosphere and accelerates them could work.

Radiative cooling scales by 4th power temperature. So if one can design electronics to run at, say, 100 C, then calling would be much less problematic.

But radiation is the real problem. Dealing with that would require entirely different architecture/design.

[inglor_cz]

"But why would you?"

Because the permitting process is much easier and there are way, way fewer authorities that can potentially shut you down.

I think this is the entire difference. Space is very, very lightly regulated, especially when it comes to labor, construction and environmental law. You need to be able to launch from somewhere and you need to automate a lot of things. But once you can do this, you escaped all but a few authorities that would hold power over you down on Earth.

No one will be able to complain that your data center is taking their water or making their electricity more expensive, for example.

[oivey]

The satellite is built on Earth, so I’m not sure how it dodges any of those regulations practically. Why not just build a fully autonomous, solar powered datacenter on Earth? I guess in space Elon might think that no one can ban Grok for distributing CSAM?

There’s some truly magical thinking behind the idea that government regulations have somehow made it cheaper to launch a rocket than build a building. Rockets are fantastically expensive even with the major leaps SpaceX made and will be even with Starship. Everything about a space launch is expensive, dangerous, and highly regulated. Your datacenter on Earth can’t go boom.

[mike_hearn]

Truly magical thinking, you say? OK, let's rewind the clock to 2008. In that year two things happened:

- SpaceX launched its first rocket successfully.

- California voted to build high speed rail.

Eighteen years later:

- SpaceX has taken over the space industry with reusable rockets and a global satcom network, which by itself contains more than half of all satellites in orbit.

- Californian HSR has spent over thirteen billion dollars and laid zero miles of track. That's more than 2x the cost of the Starship programme so far.

Building stuff on Earth can be difficult. People live there, they have opinions and power. Their governments can be dysfunctional. Trains are 19th century technology, it should be easier to build a railway than a global satellite network. It may seem truly magical but putting things into orbit can, apparently, be easier.

[inglor_cz]

"fantastically expensive"

From individual POV yes, but already Falcons are not that expensive. In the sense that it is feasible for a relatively unimportant entity to buy their launch services.

"The satellite is built on Earth, so I’m not sure how it dodges any of those regulations practically."

It is easier to shop for jurisdiction when it comes to manufacturing, especially if your design is simple enough - which it has to be in order to run unattended for years. If you outsource the manufacturing to N chosen factories in different locations, you can always respond to local pressure by moving out of that particular country. In effect, you just rent time and services of a factory that can produce tons of other products.

A data center is much more expensive to build and move around. Once you build it in some location, you are committed quite seriously to staying there.

[plorg]

So it's a Zone in search of a use case?

[DonHopkins]

Libertarian Paradise!

Too bad the fire trucks can't get to you when you catch on fire from that hot GPU.

[ericd]

Good thing the lack of oxygen does a pretty good job of taking care of that for you ;-)

[wombatpm]

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

[voidfunc]

Hello SimCity 2000 Microwave Power Plant.

[iFred]

Looking forward to an CNN breaking chyron titled "Oops!"

[habinero]

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

[wookmaster]

Why does that make sense at all

[JeremyNT]

> Why does that make sense at all

Parent said it would make more sense.

I guess in terms of the relative level of stupidity on display, it would be slightly less stupid to build huge reflectors in space than it is to try to build space datacenters, where the electricity can only power specific pieces of equipment that are virtually impossible to maintain (and are typically obsolete within a few years).

[dsr_]

Everybody wants a death ray.

[Findeton]

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

[thephyber]

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]

In situ iron, titanium, aluminum?

[nkrisc]

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).

[microtherion]

> Not only is the moon further, you also need to use more fuel to land on it

And take off again, if reusable spacecraft are meant to be used.

[sdenton4]

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

[zbentley]

And 2.5s is best case. Signal strength issues, antenna alignment issues, and all sorts of unknown unknowns conspire to make high-integrity/high-throughput digital signal transmissions from a moon-based compute system have a latency much worse than that on average.

[kakacik]

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.

[AllegedAlec]

Still a vacuum so the same heat dissipation issues, adding to it that the lunar dust makes solar panels less usable, and the lunar surface on the solar side gets really hot.

[ahoka]

It has all these problems, plus more.

[cogman10]

> 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]

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

[cogman10]

ISS cost $150B and a large factor driving that cost was the payload weight.

Minimizing payload at any point was easily worth a billion dollars. And given how heavy and nessisary the radiators are (look them up), you can bet a decent bit of research was invested in making them lightweight.

Heck, one bit of research that lasted the entire lifetime of the shuttle was improving the radiative heat system [1]. Multiple contractors and agencies invested a huge amount of money to make that system better.

Removing heat is one of the most researched problems of all space programs. They all have to do it, and every gram of reduction means big savings. Simply saying "well a DC will need more of it, therefore there must be low hanging fruit" is naive.

[1] https://llis.nasa.gov/lesson/6116

[mike_hearn]

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.

[cogman10]

> has no incentive to heavily optimize anything because the people who built it don't get rich by doing so.

Optimization is literally how contractors working for the government got rich. Every hour they spent on research was directly billed to the government. Weight reduction being one of the most important and consistent points of research.

Heck, R&D is how some of the biggest government contractors make all their dough.

SpaceX is built on the billions in research NASA has invested over the decades. It looks like it's more innovative simply because the USG decided to nearly completely defund public spending in favor of spending money on private contractors like SpaceX. That's been happening since the 90s.

[jeltz]

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

[b112]

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.

[pineaux]

that is true. They would have failed after their first failed launch. The US government saved them.

[skywhopper]

All of those “huge overheads” you cite are nothing compared to the huge overhead of building and fueling rockets to launch the vibration- and radiation-hardened versions of the solar panels and GPUs and cooling equipment that you could use much cheaper versions of on Earth. How many permitted, regulated launches would it take to get around the one-time permitting and predictable regulation of a ground-based datacenter?

Are Earth-based datacenters actually bound by some bottleneck that space-based datacenters would not be? Grid connections or on-site power plants take time to build, yes. How long does it take to build the rocket fleet required to launch a space “datacenter” in a reasonable time window?

This is not a problem that needs to be solved. Certainly not worth investing billions in, and definitely not when run by the biggest scam artist of the 21st century.

[thephyber]

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.

[krisoft]

> 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.

What do you mean we don’t have any plans to avoid that? It is a super well studied topic of satelite management. Full books have been written on the topic.

Here is just one: https://ntrs.nasa.gov/api/citations/20230002470/downloads/CA...

Did you think satelites are kept apart by good luck and providence?

[thephyber]

I am very aware that the US Air Force / Space Force monitor’s trajectories and calls satellite owners when there is an anticipated collision but that method doesn’t scale, especially with orders of magnitude more satellites in the same LEO shells.

And it still doesn’t solve the problem of a cascade causing shrapnel density to increase in an orbit shell which then causes satellites to use some of their scarce maneuver budget to avoid collision. But as soon as a satellite exhausts that budget, it becomes fodder for the shrapnel cascade.

[turtlesdown11]

>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".

[lloeki]

For another reference, the Nvidia-OpenAI deal is reportedly 10GW worth of DC.

[kimixa]

Output from radiating heat scales with area it can dissipate from. Lots of small satellites have a much higher ratio than fewer larger satellites. Cooling 10k separate objects is orders of magnitude easier than 10 objects at 1000x the power use, even if the total power output is the same.

Distributing useful work over so many small objects is a very hard problem, and not even shown to be possible at useful scales for many of the things AI datacenters are doing today. And that's with direct cables - using wireless communication means even less bandwidth between nodes, more noise as the number of nodes grows, and significantly higher power use and complexity for the communication in the first place.

Building data centres in the middle of the sahara desert is still much better in pretty much every metric than in space, be it price, performance, maintainance, efficiency, ease of cooling, pollution/"trash" disposal etc. Even things like communication network connectivity would be easier, as at the amounts of money this constellation mesh would cost you could lay new fibre optic cables to build an entire new global network to anywhere on earth and have new trunk connections to every major hub.

There are advantages to being in space - normally around increased visibility for wireless signals, allowing great distances to be covered at (relatively) low bandwidth. But that comes at an extreme cost. Paying that cost for a use case that simply doesn't get much advantages from those benefits is nonsense.

[sandworm101]

Whatever sat datacenter they biuld, it would run better/easier/faster/cheaper sitting on the ground in antarctica than it would in space, or floating on the ocean, without the launch costs. Space is useful for those activities that can only be done from space. For general computing? Not until all the empty parts of the globe are full.

This is a pump-and-dump bid for investor money. They will line up to give it to him.

[kimixa]

Yup - my example of the Sahara wasn't really a specific suggestion, so much as an example of "The Most Inconvenient Inhospitable part of the earth's surface is still much better than space for these use cases". This isn't star trek, the world doesn't match sci-fi.

It's like his "Mars Colony" junk - and people lap it up, keeping him in the news (in a not explicitly negative light - unlike some recent stories....)

[krisoft]

> Whatever sat datacenter they biuld, it will run better/easier/faster/cheaper sitting on the ground in antarctica than it will in space

That is clearly not true. How do you power the data center on antarctica? May i remind you it will be in the shadow of earth for half a year.

[idontwantthis]

Space is so expensive that you can power it pretty much any way you want and it will be cheaper. Nuclear reactor, LNG, batteries (truck them in and out if you have to). Hell, space based solar and beam it down. Why would there ever be an advantage to putting the compute in space?

[cmsj]

Get those penguins doing something productive for once, put them on treadmills!

[idontwantthis]

Or burn them in a furnace. Pretty much any way you can think of to accomplish something on earth, is vastly cheaper, easier, and faster than doing it in space.

[adrianN]

A tanker full of LNG and a turbine would probably work.

[multiplegeorges]

Kinda like the ones they are already burning in Starship to put these in space in the first place.

Anywhere on earth is better than space for this application.

[triceratops]

> How do you power the data center on antarctica?

Nuclear power plant?

[LargoLasskhyfv]

By tapping into the geothermals of the volcanoes under the ice. Otherwise nukkular.

[sandworm101]

Then you put another in the high north. Two, or six, is still cheaper than one in orbit.

[ineedasername]

Why would they bother to build space data center in such monolithic massive structures at all? Direct cables between semi-independent units the size of a star link v2 satellite. That satellite size is large enough to encompass a typical 42U server rack even without much physical reconfiguration. It doesn't need to be "warehouse sized building, but in space", and neither does it have to be countless objects kilometers apart from each other beaming data wirelessly. A few dozen wired as a cluster is much more than sufficient to avoid incurring any more bandwidth penalties on server-to-server communication with correlated work loads than we already have on earth for most needs.

Of course this doesn't solve the myriad problems, but it does put dissipation squarely in the category of "we've solved similar problems". I agree there's still no good reason to actually do this unless there's a use for all that compute out there in orbit, but that too is happening with immense growth and demand expected for increased pharmaceutical research and various manufacturing capabilities that require low/no gravity.

[bigbuppo]

Not just a 42U rack, but a 42U rack that needs one hundred thousand watts of power, and it also needs to be able to remove one hundred thousand watts of heat out of the rack, and then it needs to dump that one hundred thousand watts of heat into space.

[JoBrad]

And it needs to communicate the data to and from a ground-based location. It’s all of the problems with satellite internet, but in your production environment!

[bigbuppo]

Based on the filing for launching a million satellites, apparently their solution is to simply launch one GPU per satellite.

[LargoLasskhyfv]

Hrrm. Lemme glassballit...

Imagine a liquid which can be electrically charged, and has a low boiling point.

(Ask 3M/DuPont/BASF/Bayer... - context 'immersion cooling')

Attach heat-pipes with that stuff to the chips as is common now, or go the direct route via substrate-embedded microfluidics, as is thought of at the moment.

Radiate the shit out of it by spraying it into the vacuum, dispersing into the finest mist with highest possible surface, funnel the frozen mist back in after some distance, by electrostatic and/or electromagnetic means. Repeat. Flow as you go.

[StephenHerlihyy]

This is sort of where I think he is going with it. Run the compute part super cold (-60C) in a dielectric fluid. Maybe even at a low pressure. It boils off, gets collected, and is then condensed into something way hotter. Like boiling water hot. This is sent through a high temperature radiator for heat dispersion (because Stefan-Boltzmann has a damned 4), and then pumped back into the common storage area. Cycle indefinitely. Beyond the simple space whatever non-sense, there is a nugget of a good idea in there. Cold things are going to have less internal resistance - so they will produce less waste heat. If you can keep them at a constant temperature via submerged cooling they are also going to suffer less thermal stress due to heat fluctuations. So the vacuum of space becomes the perfect insulator. You can’t have humans getting into them anyways because then you have to reheat and recool, causing stress on the system. Just have to accept your slow component losses. Microsoft and IBM have been working the same basic concept for a while (decade plus), Elon is just throwing ‘Space!!’ into the equation because of who he is. I think it’s 50% hype and 50% this is where the industry is going regardless. I always assumed they would just find an abandoned mine or something. But the always-cold, thermally-stable, no-humans-allowed data center is coming. We are hitting the point where the upfront cost of doing it is overshadowed by the tail cost savings.

[amluto]

> Radiate the shit out of it by spraying it into the vacuum, dispersing into the finest mist with highest possible surface, funnel the frozen mist back in after some distance, by electrostatic and/or electromagnetic means. Repeat. Flow as you go.

Even if that worked, you don’t gain much. It’s not the local surface area that matters — it’s the global surface. A device confined within a 20m radius sphere can radiate no more heat than a plain black sphere of the same radius.

There are only two ways to cheat this. First, you can run hotter. But a heat pump needs power, and you need to get that power from somewhere, and you need to dissipate that power too. But you can at least run your chips as hot as they will tolerate. Second is things like lasers or radio transmitters, but those are producing non-thermal output, which is actually worse at cooling.

At the end of the day, you have only two variables to play with: the effective radiating surface temperature and the temperature of the blackbody radiation you emit.

[bigbuppo]

hits crack pipe used by elon but only after washing it thoroughly What if we used the waste heat to power a perpetual motion device that generated electricity?

[imtringued]

Congratulations! You have formed a fabric made out of satellites. You better hope it doesn't crumple.

[abalone]

> using wireless communication means even less bandwidth between nodes, more noise as the number of nodes grows, and significantly higher power use

Space changes this. Laser based optical links offer bandwidth of 100 - 1000 Gbps with much lower power consumption than radio based links. They are more feasible in orbit due to the lack of interference and fogging.

> Building data centres in the middle of the sahara desert is still much better in pretty much every metric

This is not true for the power generation aspect (which is the main motivation for orbital TPUs). Desert solar is a hard problem due to the need for a water supply to keep the panels clear of dust. Also the cooling problem is greatly exacerbated.

[Retric]

You don’t need to do anything to keep panels with a significant angle clear of dust in deserts. The Sahara is near the equator but you can stow panels at night and let the wind do its thing.

The lack of launch costs more than offset the need for extra panels and batteries.

[abalone]

What’s your source for that claim? Soiling is a massive problem for desert solar, causing as high as 50% efficiency loss in the Middle East.[1]

[1] https://www.nlr.gov/news/detail/features/2021/scientists-stu...

[Retric]

A relevant quote from that article.

“The reason I concentrate my research on these urban environments is because the composition of soiling is completely different,” said Toth, a Ph.D. candidate in environmental engineering at the University of Colorado who has worked at NREL since 2017. “We have more fine particles that are these stickier particles that could contribute to much different surface chemistry on the module and different soiling. In the desert, you don’t have as much of the surface chemistry come into play.”

[abalone]

You’re not summarizing the article fairly. She is saying the soiling mechanisms are environmentally dependent, not that there is no soiling in the desert. Again, it cites an efficiency hit of 50% in the ME. The article later notes that they’ve experimented with autonomous robots for daily panel cleaning, but it’s not a generally solved problem and it’s not true that “the wind takes care of it.”

And you still haven’t provided a source for your claim.

[funcDropShadow]

The same panel produces much more electricity in space than at the bottom of the atmosphere, because the atmosphere already reflects most of the light. Additionally, the panel needs less glass or no glass in space, which makes it lighter and cheaper.

Launch costs have shrunk significantly thanks to SpaceX, and they are projected to shrink further with the Super Heavy Booster and Starship.

[cmsj]

Space doesn't really change it though because the effective bandwidth between nodes is reduced by the overall size of the network and how much data they need to relay between each other.

[kimixa]

Yup. We don't use fibre optics on earth rather than lasers because of some specific limitation of the earth's surface being in orbit would avoid.

We use them because they're many orders of magnitude cheaper and simpler for anywhere near the same bandwidth for the distances required.

[abalone]

> We don't use fibre optics on earth rather than lasers because of some specific limitation of the earth's surface being in orbit would avoid.

That's incorrect. Lasers can suffer from atmospheric interference and fogging on earth.

Here is a post from NASA explaining why they like laser communications better than RF in space.[1]

[1] https://solc.gsfc.nasa.gov/modules/kidszone7/mainMenu_textOn...

[space_fountain]

It's like this. Everything about operating a datacenter in space is more difficult than it is to operate one on earth.

1. The capital costs are higher, you have to expend tons of energy to put it into orbit

2. The maintenance costs are higher because the lifetime of satellites is pretty low

3. Refurbishment is next to impossible

4. Networking is harder, either you are ok with a relatively small datacenter or you have to deal with radio or laser links between satellites

For starlink this isn't as important. Starlink provides something that can't really be provided any other way, but even so just the US uses 176 terawatt-hours of power for data centers so starlink is 1/400th of that assuming your estimate is accurate (and I'm not sure it is, does it account for the night cycle?)

[WillPostForFood]

What about sourcing and the cost of energy? Solar Panels more efficient, no bad weather, and 100% in sunlight (depending on orbit) in space. Not that it makes up for the items you listed, but it may not be true that everything is more difficult in space.

[3eb7988a1663]

Let's say with no atmosphere and no night cycle, a space solar panel is 5x better. Deploying 5x as many solar panels on the ground is still going to come in way under the budget of the space equivalent.

[cmenge]

And it's not the same at all. 5x the solar panels on the ground means 5x the power output in the day, still 0 at night. So you'd need batteries. If you add in bad weather and winter, you may need battery capacity for days, weeks or even months, shifting the cost to batteries while still relying on nuclear of fossil backups in case your battery dies or some 3/4/5-sigma weather event outside what you designed for occurs.

[Certhas]

Or you put the data centers at different points on earth?

Or you float them on the ocean circumnavigating the earth?

Or we put the datacenters on giant Zeppelins orbiting above the clouds?

If we are doing fantasy tech solutions to space problems, why not for a million other more sensible options?

[cmenge]

> Or you put the data centers at different points on earth? > Or you float them on the ocean circumnavigating the earth?

What that does have to do with anything? If you want to solar-power them, you still are subject to terrestrial effects. You can't just shut off a data center at night.

> Or we put the datacenters on giant Zeppelins orbiting above the clouds?

They'd have to fly at 50,000+ ft to be clear of clouds, I doubt you can lift heavy payloads this high using bouyancy given the low air density. High risk to people on the ground in case of failure because no re-entry.

> If we are doing fantasy tech solutions to space problems, why not for a million other more sensible options?

How is this a fantasy? With Starlink operational, this hardly seems a mere 'fantasy'.

[mike_hearn]

That's with current launch costs, right? Nobody is claiming it's economic without another huge fall in launch costs, but that's what SpaceX is doing.

[michaelmrose]

It wouldn't make sense if launch was free and it will never be

[PunchyHamster]

just take cost of getting kg in space and compare it to how much solar panel will generate

Current satellites get around 150W/kg from solar panels. Cost of launching 1kg to space is ~$2000. So we're at $13.3(3)/Watt. We need to double it because same amount need to be dissipated so let's round it to $27

One NVidia GB200 rack is ~120kW. To just power it, you need to send $3 240 000 worth of payload into space. Then you need to send additional $3 106 000 (rack of them is 1553kg) worth of servers. Plus some extra for piping

[cmenge]

Over 10 years ago, the best satellites had 500W/kg [2]. Modern solar panels that are designed to be light are at 200g per sqm [1]. That's 5sqm per kg. One sqm generates ca. 500W. So we're at 2.5kW per kg. Some people claim 4.3kW/kg possible.

Starship launch costs have a $100/kg goal, so we'd be at $40 / kW, or $4800 for a 120kW cluster.

120kW is 1GWh annually, costs you around $130k in Europe per year to operate. ROI 14 days. Even if launch costs aren't that low in the beginning and there's a lot more stuff to send up, your ROI might be a year or so, which is still good.

[1] - https://www.polytechnique-insights.com/en/columns/space/ultr... [2] - https://space.stackexchange.com/questions/12824/lightest-pos...

[mkesper]

What if you treat that launch costs goal as just a marketing promise. Invest in reality, not in billionaire's fantasies.

[cmenge]

> What if you treat that launch costs goal as just a marketing promise.

Then it's roughly 10x-15x and still works.

> Invest in reality, not in billionaire's fantasies.

SpaceX has dramatically reduced payload cost already. How is that a fantasy?

[OrvalWintermute]

Current state of the art Radhard & Rad Tolerant compute are way more expensive than terrestrial.

[edoceo]

I'm stretched to think of one thing that is easier in space. Anything I could imagine still requires getting there (in one piece)

[esquivalience]

Death, and some science. That's it?

[ljsprague]

Horseshoes.

[blipvert]

Achieving a zero-gravity environment, or a vacuum?

[DharmaPolice]

Noise insulation.

[pclmulqdq]

Solar panels in space are more efficient, but on the ground we have dead dinosaurs we can burn. The efficiency gain is also more than offset by the fact that you can't replace a worn out panel. A few years into the life of your satellite its power production drops.

[serallak]

If they plan to put this things in a low orbit their useful life before reentry is low anyway.

A quick search gave me a lifespan of around 5 years for a starlink satellite.

If you put in orbit a steady stream of new satellites every year maintenance is not an issue, you just stop using worn out or broken ones.

[kibwen]

Terrestrial data centers save money and recoup costs by salvaging and recycling components, so what you're saying here is that space-based datacenters are even less competitive than we previously estimated.

[ericd]

No idea how quickly they wear out in space with 24x7 irradiance and space temps, but on the earth, they’re at something like 80% capacity after 25 years. So seems like you could control how long they have via overpanelling?

[duskwuff]

> Solar panels in space are more efficient...

... if you completely ignore the difficulty of getting them up there. I'd be interested to see a comparison between the amount of energy required to get a solar panel into space, and the amount of energy it produces during its lifetime there. I wouldn't be surprised if it were a net negative; getting mass into orbit requires a tremendous amount of energy, and putting it there with a rocket is not an efficient process.

[obidee2]

My sketchy napkin math gives an order of magnitude of a few months of panel output to get it in space.

5kg, 500W panel (don’t exactly know what the ratio is for a panel plus protection and frame for space, might be a few times better than this)

Say it produces about 350kWh per month before losses.

Mass to LEO is something like 10x the weight in fuel alone, so that’s going to be maybe 500kWh. Plus cryogenics etc.

So not actually that bad

[smileeeee]

The cost might be the draw (if there is one). Big tech isn't afraid of throwing money at problems, but the AI folk and financiers are afraid of waiting and uncertainty. A satellite is crazy expensive but throwing more money at it gets you more satellites.

At the end of the day I don't really care either way. It ain't my money, and their money isn't going to get back into the economy by sitting in a brokerage portfolio. To get them to spend money this is as good a way as any other, I guess. At least it helps fund a little spaceflight and satellite R&D on the way.

[actionfromafar]

It's just tax payer money, who cares right? :)

[murderfs]

> The maintenance costs are higher because the lifetime of satellites is pretty low

Presumably they're planning on doing in-orbit propellant transfer to reboost the satellites so that they don't have to let their GPUs crash into the ocean...

[mlyle]

Another significant factor is that radiation makes things worse.

Ionizing radiation disrupts the crystalline structure of the semiconductor and makes performance worse over time.

High energy protons randomly flip bits, can cause latchup, single event gate rupture, destroy hardware immediately, etc.

[Aerolfos]

If anything, considering this + limited satellite lifetime, it almost looks like a ploy to deal with the current issue of warehouses full of GPUs and the questions about overbuild with just the currently actively installed GPUs (which is a fraction of the total that Nvidia has promised to deliver within a year or two).

Just shoot it into space where it's all inaccessible and will burn out within 5 years, forcing a continuous replacement scheme and steady contracts with Nvidia and the like to deliver the next generation at the exact same scale, forever

[XorNot]

And just like that you've added another not never done before, and definitely not at scale problem to the mix.

These are all things which add weight, complexity and cost.

Propellant transfer to an orbital Starship hasn't even been done yet and that's completely vital to it's intended missions.

[JumpCrisscross]

> Presumably they're planning on doing in-orbit propellant transfer to reboost the satellites so that they don't have to let their GPUs crash into the ocean

Hell, you're going to lose some fraction of chips to entropy every year. What if you could process those into reaction mass?

[3eb7988a1663]

I believe that a modern GPU will burn out immediately. Chips for space are using ancient process nodes with chunky sized components so that they are more resilient to radiation. Deploying a 3nm process into space seems unlikely to work unless you surround it with a foot of lead.

[mike_hearn]

Or cooling water/oil?

[JumpCrisscross]

> Or cooling water/oil?

Oh. You surround it with propellant. In a propellant depot.

[falcor84]

This brings a whole new dimension to that joke about how our software used to leak memory, then file descriptors, then ec2 instances, and soon we'll be leaking entire data centers. So essentially you're saying - let's convert this into a feature.

[lambdaone]

It's certainly one way to do arena-based garbage collection.

[notahacker]

Reminds me of the proposal to deorbit end of life satellites by puncturing their lithium batteries :)

The physics of consuming bits of old chip in an inefficient plasma thruster probably work, as do the crawling robots and crushers needed for orbital disassembly, but we're a few years away yet. And whilst on orbit chip replacement is much more mass efficient than replacing the whole spacecraft, radiators and all, it's also a nontrivial undertaking

[sanex]

Or maybe they want to just use them hard and deorbit them after three yesrs?

[zeofig]

"Planning" is a strong word..

[trhway]

>1. The capital costs are higher, you have to expend tons of energy to put it into orbit

putting 1KW of solar on land - $2K, putting it into orbit on Starship (current ground-based heavy solar panels, 40kg for 4m2 of 1KW in space) - anywhere between $400 and $4K. Add to that that the costs on Earth will only be growing, while costs in space will be falling.

Ultimately Starship's costs will come down to the bare cost of fuel + oxidizer, 20kg per 1kg in LEO, i.e. less than $10. And if they manage streamlined operations and high reuse. Yet even with $100/kg, it is still better in space than on the ground.

And for cooling that people so complain about without running it in calculator - https://news.ycombinator.com/item?id=46878961

>2. The maintenance costs are higher because the lifetime of satellites is pretty low

it will live those 3-5 years of the GPU lifecycle.

[javascriptfan69]

Current cost to LEO is $1500 per kg

That would make your solar panel (40kg) around $60K to put into space.

Even being generous and assuming you could get it to $100 per kg that's still $4000

There's a lot of land in the middle of nowhere that is going to be cheaper than sending shit to space.

[trhway]

>That would make your solar panel (40kg) around $60K to put into space.

with the GPU costing the same, it would only double the capex.

>Even being generous and assuming you could get it to $100 per kg that's still $4000

noise compare to the main cost - GPUs.

>There's a lot of land in the middle of nowhere that is going to be cheaper than sending shit to space.

Cheapness of location of your major investment - GPUs - may as well happen to be secondary to other considerations - power/cooling capacity stable availability, jurisdiction, etc.

[estomagordo]

> with the GPU costing the same, it would only double the capex.

Yes, only doubling the capex. With the benefits of, hmm, no maintenance access and awful networking?

[ndsipa_pomu]

Don't forget the major problem with cooling

[iso1631]

> jurisdiction

This is the big thing, but Elon's child porn generator in orbit will be subject to US jurisdiction, just as much as if they were in Alaska. I guess he can avoid state law.

If jurisdiction is key, you can float a DC in international waters on a barge flying the flag of Panama or similar flag of convenience which you can pretty much buy at this scale. Pick a tin-pot country, fling a few million to the dictator, and you're set - with far less jurisdiction problems than a US, Russia, France launched satellite.

[blackoil]

Any idea, what is the estimated cost of a Google TPU. It may not make sense for Nvidia retail price but at cost price of Google.

[trhway]

Can only speculate out of thin air - B200 and Ryzen 9950x made on the same process and have 11x difference in die size. 11 Ryzens would cost $6K, and with 200Gb RAM - $8K. Googling brings that the B200 cost or production is $6400. That matches the numbers from the Ryzen based estimate above (Ryzen numbers is retail, yet it has higher yield, so balance). So, i'd guess that given Google scale a TPU similar to B200 should be $6K-$10K.

[ericd]

I think the disconnect is that with starship they’re targeting >200 tons/200,000 kg and $2m-$10m/launch, so the very optimistic case is more like $10/kg. Also, the production of a panel in sun sync orbit is many times one on the ground, doesn’t suffer seasonality/weather, and doesn’t require battery storage for smoothing/time shifting, so you’d need to deploy many times the number of panels on earth. Our home array in North America over the course of the year generates something like 1/7th of its theoretical capacity, overproduces in the summer, and underproduces in the winter.

[pclmulqdq]

> putting 1KW of solar on land - $2K, putting it into orbit on Starship (current ground-based heavy solar panels, 40kg for 4m2 of 1KW in space) - anywhere between $400 and $4K.

What starship? The fantasy rocket Musk has been promising for 10 years or the real one that has thus far delivered only one banana worth of payload into orbit?

[trhway]

it is obviously predicated on Starship. All these discussions have no sense otherwise.

> or the real one that has thus far delivered only one banana worth of payload into orbit?

once it starts delivering real payloads, the time for discussions will be no more, it will be time to rush to book your payload slot.

[gspr]

You are presented with a factual, verifiable, statement that starship has been promised for years and that all that's been delivered is something capable of sending a banana to LEO. Wayyyy overdue too.

You meet this with "well, once it works, it'll be amazing and you'll be queuing up"? How very very musky!

What a cult.

[ben_w]

I have no idea if SpaceX will ever make the upper stage fully reusable. The space shuttle having existed isn't an existence proof, given the cost of repairs needed between missions.

However, with Starship SpaceX has both done more and less than putting a banana in orbit. Less, because it's never once been a true orbit; more, because these are learn-by-doing tests, all the reporting seems to be in agreement that it could already deliver useful mass to orbit if they wanted it to.

But without actually solving full reusability for the upper stage, this doesn't really have legs. Starship is cheap enough to build they can waste loads of them for this kind of testing, but not cheap enough for plans such as these to make sense if they're disposable.

[ENGNR]

They also launched dummy satellites from the "pez dispenser", directly simulating the actual mission payload, about 4 months ago.

[viraptor]

> will come down to the bare cost of fuel + oxidizer

And maintenance and replacing parts and managing flights and ... You're trying to yadda-yadda so much opex here!

[trhway]

It is SpaceX/Elon who bet billions on that yadda-yadda, not me. I wrote "If" for $10/kg. I'm sure though that they would easily yadda-yadda under sub-$100/kg - which is $15M per flight. And even with those $100/kg the datacenters in space still make sense as comparable to ground based and providing the demand for the huge Starship launch capacity.

A datacenter costs ~$1000/ft^2. How much equipment per square foot is there? say 100kg (1 ton per rack plus hallway). Which is $1000 to put into orbit on Starship at $100/kg. At sub-$50/kg, you can put into orbit all the equipment plus solar panels and it would still be cheaper than on the ground.

[sarchertech]

It looks like you’re comparing the cost of installing solar panels on the ground with the cost of just transporting them to orbit. You can’t just toss raw solar panels out of a cargo bay.

[trhway]

>You can’t just toss raw solar panels out of a cargo bay.

That is exactly what you do - just like with Starlink - toss out the panels with attached GPUs, laser transmitter and small ion drive.

[gf000]

> it is SpaceX/Elon

The known scammer guy? Like these ideas wouldn't pass the questions at the end of a primary school presentation.

[javascriptfan69]

100 x 100 is 10,000.

[bildung]

1 KW of solar panels is 150€ retail right now. You are probably at 80€ or less if you buy a few MW.

(I'm ignoring installation costs etc. because actually creating the satellites is ignored here, too)

[tpm]

installation of large solar plants is largely automated already

[iso1631]

My car costs far more per mile than the bare cost of the fuel. Why would starship not have similar costs?

[reverius42]

The bean counters at NVidia recently upped the expected lifecycle from 5 years to 6. On paper, you are expected now to get 6 years out of a GPU for datacenter use, not 3-5.

[blackoil]

To add space solar cell will weigh only 4-12kg as protection requirements are different.

[estomagordo]

source?

[blackoil]

:| Did rough calculations with help of ChatGPT. In space it need not be hardened for rain, hail, wind and dust but for radiation and micro meteors.

[shagie]

Compare the cost of a RAD750 (the processor on the JWST) to its non rad hardened variant. Additionally, consider the processing power of that system to modern AI demands.

[JumpCrisscross]

> Everything about operating a datacenter in space is more difficult than it is to operate one on earth

Minus one big one: permitting. Every datacentre I know going up right now is spending 90% of their bullshit budget on battlig state and local governments.

[dantillberg]

But since building a datacenter almost anywhere on the planet is more convenient than outer space, surely you can find some suitable location/government. Or put it on a boat, which is still 100 times more sensible than outer space.

[JumpCrisscross]

> since building a datacenter almost anywhere on the planet is more convenient than outer space, surely you can find some suitable location/government

More convenient. But I'm balancing the cost equation. There are regimes where this balances. I don't think we're there yet. But it's irrational to reject it completely.

> Or put it on a boat, which is still 100 times more sensible than outer space

More corrosion. And still, interconnects.

[GCUMstlyHarmls]

> More corrosion

Surely given starlinks 5ish year deorbit plan, you could design a platform to hold up for that long... And instead of burning the whole thing up you could just refurbish it when you swap out the actual rack contents, considering that those probably have an even shorter edge lifespan.

[m4rtink]

Starlinks are built to safely burn up on re-entry. A big reusable platform will have to work quite differently to never uncontrollably re-enter, or it might kill someone by high velocity debris on impact.

This adds weight and complexity and likely also forces a much higher orbit.

[m4rtink]

If you think there is no papework necessary for launching satellites, you are very very wrong.

[JumpCrisscross]

> If you think there is no papework necessary for launching satellites, you are very very wrong

I would be. And granted, I know a lot more about launching satellites than building anything. But it would take me longer to get a satellite in the air than the weeks it will take me to fix a broken shelf in my kitchen. And hyperscalers are connecting in months, not weeks.

[BurningFrog]

It's also infinitly easier to get 24/7 unadulterated sunlight for your solar panels.

[dantillberg]

Not 24/7 in low earth orbit, but perhaps at an earth-moon or earth-sun L4/L5 lagrange point. Though with higher latency to earth.

[BurningFrog]

There are Sun-Synchronous Orbits, and those are what SpaceX plans to use: https://en.wikipedia.org/wiki/Sun-synchronous_orbit

[dantillberg]

Well, that's neat. TIL. Thanks for the link!

[fodkodrasz]

So what? Why is it important to have 24/7 solar, that you cannot have on the ground? On the ground level you have fossil fuels.

I wonder if you were thinking about muh emissions for a chemical rocket launched piece of machinery containing many toxic metals to be burnt up in the air in 3-5 years... It doesn't sound more environmentally friendly.

[BurningFrog]

Getting enough energy for your AI data centers is one of the most limiting factors for AI technology.

Solar in space is about 5-10x as effective as solar on the ground.

[fodkodrasz]

So what? Just build some nuclear power plants if AI data centers are so important. It can even work at night when it is infinitely as effective as solar on the ground!

Also I'm astounded how important AI data centers are when we are running out of freshwater, to mention a thing we could easily solve with focusing our efforts on it instead of this. But yeah, surely the Space AI Data Centers (aka. "SkyNet") is the most important we must build...

Also this is just about Elon jumping the shark...

[bdangubic]

that may have been the case before but it is not anymore. I live in Northern VA, the capital of the data centers and it is easier to build one permit-wise than a tree house. also see provisions in OBBB

[floatrock]

I mean, you don't have zoning in space, but you have things like international agreements to avoid, you know, catastrophic human development situations like kessler syndrome.

All satellites launched into orbit these days are required to have de-orbiting capabilities to "clean up" after EOL.

I dunno, two years ago I would have said municipal zoning probably ain't as hard to ignore as international treaties, but who the hell knows these days.

[JumpCrisscross]

> you have things like international agreements to avoid, you know, catastrophic human development

Yes. These are permitted in weeks for small groups, days for large ones. (In America.)

Permitting is a legitimate variable that weighs in favor of in-space data centers.

[viraptor]

> is spending 90% of their bullshit budget on battlig state and local governments

Source? I can't immediately find anything like that.

[kelseyfrog]

Parent just means "a lot" and is using 90% to convey their opinion. The actual numbers are closer to 0.083%[1][2][3][4] and parent thinks they should be 0.01-0.1% of the total build cost.

1. Assuming 500,000 USD in permitting costs. See 2.

2. Permits and approvals: Building permits, environmental assessments, and utility connection fees add extra expenses. In some jurisdictions, the approval process alone costs hundreds of thousands of dollars. https://www.truelook.com/blog/data-center-construction-costs

3. Assuming a 60MW facility at $10M/MW. See 4.

4. As a general rule, it costs between $600 to $1,100 per gross square foot or $7 million to $12 million per megawatt of commissioned IT load to build a data center. Therefore, if a 700,000-square foot, 60-megawatt data center were to be built in Northern Virginia, the world’s largest data center market, it would cost between $420 million and $770 million to construct the facility, including its powered shell and equipping the building with the appropriate electrical systems and HVAC components. https://dgtlinfra.com/how-much-does-it-cost-to-build-a-data-...

[viraptor]

Yeah, I was trying to be nicer than "you're making it up" just in case someone has the actual numbers.

[mike_hearn]

He said bullshit budget, not budget. He's thinking about opportunity and attention costs, not saying that permits literally have a higher price tag than GPUs.

[kelseyfrog]

Maybe try meditation? It can help deal with negative emotions.

[sapphicsnail]

What counts towards a bullshit budget? Permitting is a drop in the bucket compared to construction costs.

[deepGem]

This is a huge one. What Musk is looking for is freedom from land acquisition. Everything else is an engineering and physics problem that he will somehow solve. The land acquisition problem is out of his hands and he doesn't want to deal with politicians. He learned from building out the Memphis DC.

[markhahn]

Maybe, but I'm skeptical, because current DCs are not designed to minimize footprint. Has anyone even built a two-story DC? Obviously cooling is always an issue, but not, directly, land.

Now that I think of it, a big hydro dam would be perfect: power and cooling in one place.

[mbushey]

> Has anyone even built a two-story DC?

Downtown Los Angeles: The One Wilshire building, which is the worlds most connected building. There are over twenty floors of data centers. I used Corporate Colo which was a block or two away. That building had at least 10 floors of Data Centers.

[reverius42]

I think Downtown Seattle has a bunch too (including near Amazon campus). I just looked up one random one and they have about half the total reported building square footage of a 10-story building used for a datacenter: https://www.datacenters.com/equinix-se3-seattle

[lambdaone]

Multistory DCs are commonplace in major cities.

[bigfatkitten]

> Has anyone even built a two-story DC?

Every DC I’ve been in (probably around 20 in total) has been multi storey.

[deepGem]

Skepticism is valid. The environmentalists came after dams too.

[EdwardDiego]

So freedom from law and regulation?

[blactuary]

He "learned" by illegally poisoning black people

> an engineering and physics problem that he will somehow solve

no he won't

[tw04]

Amazon’s new campus in Indiana is expected to use 2.2GW when complete. 50Mw is nothing, and that’s ignoring the fact that most of that power wouldn't actually be used for compute.

[Aurornis]

> Isn't 50MW already by itself equivalent to the energy consumption of a typical hyperscaler cloud?

xAI’s first data center buildout was in the 300MW range and their second is in the Gigawatt range. There are planned buildouts from other companies even bigger than that.

So data center buildouts in the AI era need 1-2 orders of magnitude more power and cooling than your 50MW estimate.

Even a single NVL72 rack, just one rack, needs 120kW.

[javascriptfan69]

Starlink provides a service that couldn't exist without the satellite infrastructure.

Datacenters already exist. Putting datacenters in space does not offer any new capabilities.

[_fizz_buzz_]

This is the main point I think. I am very much convinced that SpaceX is capbable to put a datacenter into space. I am not convinced they can do it cheaper than building a datacenter on earth.

[notahacker]

I would be a lot more convinced they had found a way to solve the unit economics if it was being used to secure billion dollar deposits from other companies rather than as the narrative for rolling a couple of Elon's loss making companies into SpaceX and IPOing...

[jdhwosnhw]

> A Starlink satellite uses about 5K Watts of solar power. It needs to dissipate around that amount (+ the sun power on it) just to operate.

The “+ solar power” part is the majority of the energy. Solar panel efficiency is only about 25-30% at beginning-of-life whereas typical albedos are effectively 100%. So your estimate is off by at least a factor of three.

Also, I’m not sure where you got 5 kw from. The area of the satellite is ~100 m2, which means they are intercepting over 100 kw of bolometric solar power.

[pdpi]

5kW means you can't even handle a single one of these[0], compared to a handful per rack on an earthbound data centre.

0. https://www.arccompute.io/solutions/hardware/gpu-servers/sup...

[MadnessASAP]

I ran the math the last time this topic camps up

The short answer is that ~100m2 of steel plate at 1400C (just below its melting point) will shed 50MW of power in black body radiation.

https://news.ycombinator.com/item?id=46087616#46093316

[adrian_b]

The temperature of space datacenters will be limited to 100 Celsius degrees, because otherwise the electronic equipment will be destroyed.

So your huge metal plate would radiate (1673/374)^4 = 400 times less heat, i.e. only 125 kW.

In reality, it would radiate much less than that, even if made of copper or silver covered with Vantablack, because the limited thermal conductivity will reduce the temperature for the parts distant from the body.

[ViewTrick1002]

Which GPU runs at 1400C?

[MadnessASAP]

One made of steel presumably.

I would assume such a setup involves multiple stages of heat pumps to from GPU to 1400C radiatoe. Obviously that's going to impact efficiency.

Also I'm not seriously suggesting that 1400C radiators is a reasonable approach to cooling a space data centre. It's just intended to demonstrate how infeasible the idea is.

[adrian_b]

The idea of using heat pumps to increase the temperature of the radiator is unlikely to allow an increase of the fraction of the original amount of heat that is radiated per heatsink surface, i.e. the added heat may be higher than the additionally radiated heat, though I am too lazy to compute now whether this is possible.

Moreover, a heat pump would add an equipment with moving parts that can fail, requiring maintenance.

[gclawes]

Starlink satellites also radiate a non-trivial amount of the energy they consume from their phased arrays

[markhahn]

50MW is on the small side for an AI cluster - probably less than 50k gpus.

if the current satellite model dissipates 5kW, you can't just add a GPU (+1kW). maybe removing most of the downlink stuff lets you put in 2 GPUs? so if you had 10k of these, you'd have a pretty high-latency cluster of 20k GPUs.

I'm not saying I'd turn down free access to it, but it's also very cracked. you know, sort of Howard Hughesy.

[hackernudes]

High latency to earth but low latency (potentially) to other satellites.

[kristjansson]

50MW might be one aisle of a really dense DC. A single rack might draw 120kW.

[ErroneousBosh]

> A Starlink satellite uses about 5K Watts of solar power

Is that 5kW of electrical power input at the terminals, or 5kW irradiation onto the panels?

Because that sounds like kind of a lot, for something the size of a fridge.

[padjo]

Are starlink satellites in sun synchronous orbits? Doesn't constant solar heating change the energy balance quite a bit?

[antonvs]

> Why is starlink possible and other computations are not?

Aside from the point others have made that 50 MW is small in the context of hyperscalers, if you want to do things like SOTA LLM training, you can't feasibly do it with large numbers of small devices.

Density is key because of latency - you need the nodes to be in close physical proximity to communicate with each other at very high speeds.

For training an LLM, you're ideally going to want individual satellites with power delivery on the order of at least about 20 MW, and that's just for training previous-generation SOTA models. That's nearly 5,000 times more power than a single current Starlink satellite, and nearly 300 times that of the ISS.

You'd need radiator areas in the range of tens of thousands of square meters to handle that. Is it theoretically technically possible? Sure. But it's a long-term project, the kind of thing that Musk will say takes "5 years" that will actually take many decades. And making it economically viable is another story - the OP article points out other issues with that, such as handling hardware upgrades. Starlink's current model relies on many cheap satellites - the equation changes when each one is going to be very, very expensive, large, and difficult to deploy.

[whiplash451]

Not related to heat, but a com satellite is built from extremely durable HW/SW that's been battle-tested to run flawlessly over years with massive MTBF numbers.

A data center is nowhere near that and requires constant physical interventions. How do they suggest to address this?

[PurpleRamen]

A Starlink satellite is mainly just receiving and sending data, the bare minimum of a data center-satellite's abilities; everything else comes on top and would be the real power drain.

[michaelmrose]

Why would anyone think the unit cost would be competitive with cheap power / land on earth? If that doesn't make sense how could anything else?

[adgjlsfhk1]

> A Starlink satellite uses about 5K Watts of solar power. It needs to dissipate around that amount (+ the sun power on it) just to operate.

This isn't quite true. It's very possible that the majority of that power is going into the antennas/lasers which technically means that the energy is being dissipated, but it never became heat in the first place. Also, 5KW solar power likely only means ~3kw of actual electrical consumption (you will over-provision a bit both for when you're behind the earth and also just for safety margin).

[rootnod3]

Forget heat. Replacing disks alone is a deal breaker on that one.

[Sharlin]

Square–cube law.

[chairmansteve]

A typical desktop/tower PC will consume 400 watts. So 12 PC's equals 1 starlink satellite.

A single server in a data center will consume 5-10 kW.

[phs318u]

Because 10K satellites have a FAR greater combined surface area than a single space-borne DC would. Stefan-Boltzman law: ability to radiate heat increase to the 4th power of surface area.

[thebolt00]

It's linear to surface area, but 4th power to temperature.

[dguest]

Also worth noting that if computing power scales with volume then surface area (and thus radiation) scales like p^2/3. In other words, for a fixed geometry, the required heat dissipation per unit area goes like p^1/3. This is why smaller things can just dissipate heat from their surface, whereas larger things require active cooling.

I'm not a space engineer but I'd imagine that smaller satellites can make due with a lot of passive cooling on the exterior of the housing, whereas a shopping-mall sized computer in space would will require a lot of extra plumbing.

[phs318u]

Thanks for the correction. Last time I looked at it was in 2nd year Thermodynamics in 1985.

[cjfd]

Sure, we can run the math on heat dissipation. The law of Stefan-Boltzman is free and open source and it application is high school level physics. You talk about 50 MW. You are going to need a lot of surface area to radiate that off at somewhere close to reasonable temperatures.

[ndsipa_pomu]

> The law of Stefan-Boltzman is free and open source... What do you mean by "open source"? Can we contribute changes to it?