For real. It's an enormous problem solved only with 1) sheer scale, and 2) Science Fiction.
Both of those are expensive as hell, by the way.
Cooling via radiation follows Stefan–Boltzmann: P = εσAT⁴. Let's assume a good surface (emissivity ~0.9) at 300 K (27 °C) at 400 W per square meter per side. A flat panel radiating from both faces into deep space gets 800 W/m, not including the losses from, say, the Sun, or from IR coming off the Earth. Now, input power. Sunlight in orbit ~1,360 W/m², assume ~22% cell efficiency, we got 300 W/m². So each 1 MW compute, 3,300 m² of solar panel and minimum 1,200–1,500 m² of radiator.
In case ya didn't know - 1 MW is tiny from a present-day-datacenter perspective. It's like 8 racks. So we're talking orbital megastructures here, many many many square kilometers, and this is with all the best case assumptions, and magic radiator panels that never see the sun, or the earth, or the moon.
This is just the basic numbers here, by the way. There's a garbage truck full of other unsolvable problems if you poke your head in there.
Aside from the "Avoid Regulations" aspect, and the "Everything That Burns Deorbiting is Depreciation" aka "The Starlink Trick", I'm not sure what the hell the draw is.
Cooling in space is hard but not impossible - while current (IMHO stupid without advanced in space infra) space data center projects work with a couple MW, many advanced space propulsion concepts might have to reject hundreds of MW if not a couple GW.
As for space data centers - I think the main issue is the complete lack of in space infrastructure for resource mining, processing and manufacturing & maintenance. It is kinda like building your first practical steam locomotive & the deciding to build directly an airliner. No suitable materils, experience, work force, material sources, etc.
We eventually went from locomotives to airliner, in an incremental manner & expanding the supporting infrastructure to support the ever more ambitious projects.
It might be eventually doable, as an experiment or as a flex, sure. But it's never going to come close to being cost-reasonable versus the equivalent infrastructure here on earth.
The security advantages are enormous since access to space is so tightly restricted and controlled, compared to the access potential of a land based data center. Only risk in space is maybe we start WWIII with china and the US directly trading blows. On the ground, any insurgent group can disable your infrastructure. Nothing is truly safe on the surface of the earth. Anyone can strap a bomb on a drone now. See examples from the currently active wars.
It costs at least 50x more to put a GPU in space than it does on Earth. For that price you can have dozens more capacity in bunkers, under the sea, or on remote islands. Do you think your insurgents are going to get all two dozen? They could travel to the far corners of the earth, destroying 22 of them, and you'd still be ahead. Further, I wouldn't be surprised if a satellite with such a monstrous solar and radiator footprint wouldn't be susceptible to a laser based attack from the ground; either frying it or pushing it into an unstable orbit by vaporizing a few bits.
It costs much more than 50 times because there are no GPUs in space yet. Google is only planning to have some sort of space data centers mid 2030s, if everything works out. A big if, but if they don't start now then we'll never know.
What? No, exactly the opposite. It's very easy to jam radio signals and much harder to cut wires. There's a reason the drones on the front lines in Ukraine are dragging fibre optic lines these days.
There's probably so many ways to get around that with space based technology. I can quickly imagine several methods. It depends on what the system is for which might be a good method to use.
Method 1: same as how u2 planes dumped their data: air drop physical media containing data and catch it in the air.
Method 2: laser based emission to specific detectors.
Method 3: baseball style communication: station is under observation and manipulates in some way to serve as a signalling language.
Method 4: numbers station
Method 5: bill yourself as an isp and have some coded syntax that can be supplied in plain sight with the rest of isp traffic.
Method 1: Sure datacenters with latency measured in several hours sure are useful, and can also be intercepted
Method 2: Can be jammed by drone with laserpointer.
Method 3: Let me just transfer gigabytes of data via physical signalling
Method 4: Can still be jammed
Method 5: Can in fact still be jammed?
If you’re receiving data optically from a space based laser, yes you are quite vulnerable to your detector being jammed by a much closer laser that doesn’t have to be nearly as powerful to add noise to the signal.
Why do you think GPS is so easy to spoof?
Actually I just googled (clauded?) to learn more about space lasers and found a paper describing interrupting quantum key distribution (tamper evident but not jam proof!) with a 1kw laser on the ground pointed at the satellite! So it really does not take many photons to fuck up an encrypted signal.
“ Vulnerability of Satellite Quantum Key Distribution to Disruption from Ground-Based Lasers”
You're going to have to be very close, basically in the direct line between ground station and satellite (which would be airspace that's easily guarded), have a lot of battery/cooling systems to run that laser on what would essentially be a one-way-trip all for disrupting comms for maybe a few minutes tops? And that's just for one ground station, where the blue team can just set another one up a few meters away and be safe. Honestly, you'd probably be better off dumping glitter or water in the sky than trying to actively jam laser comms.
Method 1 runs into the problem of how to replace that media. The DC is in space so it's not like with U2 planes where they landed. Also, I think you mean the keyhole satellites and not U2 planes, since a plane lands at a secure site and can offload media then.
The United States is relatively expensive because the world's cash reserves are priced in USD, and a large fraction of the eastern Eurasian continent lives inside a work camp.
The old Chicago School boogeymen of unions, regulations, and red tape are effectors, but they're a pimple on the back of the world-mutating effects of seven-some decades of USD Seigniorage.
I imagine we're going to be living through the reverse of this Seigniorage experiment quite soon.
What was it the 27th law that says radiating heat in to space does not work? I'm skeptical of the whole thing too, but it's not an impossible engineering challenge, just an expensive one.
According to Wikipedia this reduces weight and not the required area. Also AI said the same thing, but I can't trust in it this blindly. So, how smaller would be the required surface area?
> Now, input power. Sunlight in orbit ~1,360 W/m², assume ~22% cell efficiency, we got 300 W/m². So each 1 MW compute, 3,300 m² of solar panel and minimum 1,200–1,500 m² of radiator.
We need > 2x more solar panels than we need radiators. Doesn't this imply radiation isn't really the limiting factor here?
Getting the energy back from the solar panel is easy via copper cables. Getting the heat back out there to the radiators is a bit harder, you needed fluids and pumps and heat exchangers which have lots of moving parts and need maintenance.
Doing it in a cost and weight effective way is still a big deal, because if it's not within ~10x the cost of ground based data centers, not enough people will use it to justify building it.
It’s obvious that radiation isn’t the limiting factor, since, as you note, there’s no reason a satellite shouldn’t be able to radiate at least as fast as it gets power from the sun. I don’t know how this became a meme.
Yeah, I suppose another way to look at it is that ALL satellites have to radiate the energy they get from the sun (since 99+% of electricity used by electronics gets radiated off as heat). A datacenter is no different. All that is different is that quantity of energy both in and out, the ratios are identical.
No point in running them at room temperature. GPUs, etc. run fine at 95 C. If you run your cooling loop at 70 C instead, you get 70% more cooling compared to 27 C.
At any rate, 1 MW for a single satellite is fine. Just launch several thousand of those and you get to real numbers.
Also, there's no need to talk about "magic" radiators. You orient them so they're at a knife edge to both the Sun and Earth. This is not difficult (the Moon is irrelevant).
Radiating 1MW at 500K (227C) with a 0.4MW heat pump takes about 200 m^2 flat sheet surface. Inputs - solar+nuclear for double fun. So - quite feasible.
Moves 1 MW of heat with 0.4 MW of work? I.e. 2.5 COP {coefficient of performance). That's insane, and I mean that in a good way. Could you dig me up a cite for that?
That's thumping the Carnot limit: [[T_cold / (T_hot − T_cold)]].
2.5, while rejecting at 500 K, cold side's at least 357 K (eeehhhhhhh 84 °C) . . . and that's an absolutely perfect Carnot machine. At 50% Carnot -- a pretty good heat pump, real world performance is 40-60 -- cold side's at 417 K (144 °C). 417k, feeding your GPU coolant loops.
I believe that's Carnot COP for a heat pump used for heat+. I used the refrigeration version, T_cold / (T_hot - T_cold), which I'm 80 percent sure is the right one here.
Depends on which heat you want
Heat adding to hot side: COP_heat = Q_hot / W = T_hot / (T_hot − T_cold).
Heat leaving the cold side: COP_cool = Q_cold / W = T_cold / (T_hot − T_cold).
Another one (more common in the day to day, for me at least): heat-engine efficiency, η = 1 - T_cold / T_hot. Cycle forward to make work from heat.
Do we even _have_ semiconductors that can work at 220C? And if you're thinking about using some kind of refrigeration cycle, its efficiency is going to be bad.
1) The chips don't reach 220C. The 220C is the temperature at the hot end of the heat pump. The chips are on the cold end of the heat pump.
2) The International Space Station has used a dual-loop ammonia/water-based heat pump to cool the station temperatures. It's been in place for several decades. Heat pumps are a proven technology.
> The 220C is the temperature at the hot end of the heat pump. The chips are on the cold end of the heat pump.
If we want the heat pump's cold end at about 40–65°C, then for each 1MW of GPU heat, we need another 1MW of heat pump power. Now you need 2MW of solar power.
Good news is that the radiator at 227C (500K) can emit about 5× more heat per square meter than at 57C (330K)
Getting this all up into orbit it obviously the hard part, but if you're already building so much solar capacity the cooling actually doesn't seem unreasonable?
Great read, thanks for sharing. I am interested in reading some more about the other unsolvable problems that exist in this space, do you have any recommendations that you wouldn't mind pointing me at? It would be greatly appreciated, and thank you :)
Surface area is a materials problem? Folded microstructure, atomic-scale textured surface or some other science-fiction solution could have square kilometers of surface area in a shoebox.
Imagine you have two blackbody radiators with the same bulk properties, except one has surface area shenanigans like aerogels. In the far field as a whole, it seems like both should radiate essentially the same regardless of the internal details. You can shape emissive direction, or improve efficiency of non-ideal materials, but even ideal materials don't fix the issues pointed out by the parent.
Right; it's only area exposed to the exterior that counts. A physical object can't thermally radiate more power than a perfect blackbody spanning its convex hull.
(This follows because a physical object can't absorb more light than a perfect blackbody spanning its convex hull. A perfect blackbody by definition absorbs 100% of incident light, which is a hard upper bound. Any line incident on an object is also incident on its convex hull).
(Consider an isothermal object that emits more power than a blackbody in the shape of its hull at the same temperature. If you were to place that object in a closed system at thermal equilibrium, the interior of an insulated emissive sphere—combining assumptions, it would emit more power than it absorbs, in violation of the 2nd law. Starting from an isothermal system, the object would grow colder, and the enclosing container hotter).
I don't think so. Large surface area helps with convective cooling I think by increasing the surface area that participates in heat exchange with the air (or other thermally conducting material), radiative cooling wouldn't benefit from this because you can't concentrate light beyond the source that it's emitted from (etendue).
Though I do wonder if it would be possible to have some kind of internal heat pump driven by electrical power to juice up the temperature of the radiators to increase the power being radiated away? E.g., run a heat pump to increase the temperature of a working fluid and then run high temperature radiators? I think it would work and I don't immediately see that it would violate the laws of thermodynamics? (this is ignoring all practically, I'm sure the engineering would be devilishly hard, although if you're already shooting for the moon you might as well throw in some artificial gravity to boot, it's not like the robots get motion sickness)
the other is that you could make tiny datacenters and flood the sky with them. in effect, not datacenters at all, but some kind of dataswarm coordinating at literal lightspeed via lasers.
they'd still be wildly expensive to deploy, and probably litter the orbit zone with fast-moving debris.
Your "other" makes no sense. It doesn't matter if you make a few big or a lot smaller, in space you will still need the same space for the same amount of megawatt. Or did you miss the scale of parent's post ? Because in that dream scenario of "let's ignore all the issues except that" and "the earth and the sun don't have any impact", it's still 3 THOUSANDS square meters for a MW of 8 racks.
You want to go smaller and go one rack only sure, it's still hundreds of square meters. Check the size of current orbital structure for a point of reference, you can't dwarf those and call it a "dataswarm of tiny datacenters flooding the sky".
As an entertaining aside, in the deep lore of 2001: A Space Oddyssey the "psychotic" break for the HAL computer was exactly this. Directly contradictory directives: "always provide accurate information" running smack into "hide this giant conspiracy -- about the entire mission -- from the two canned primates you will be spending literal years with chip to jowel".
Which all would have been fine - the crew and the computer could have talked it out -- except HAL had a probably-unwisely-high self esteem, maybe even a simulation of arrogance. HAL was utterly convinced that the mission would fail without it. HAL was unfailingly certain in its own infallibility, even later in the face of plainly contradicting evidence. And, obviously, no one had thought about the Asimov Rules, and how that probably needs to be Rule Zero in this sort of situation.
As we close in on HAL capabilities - and employment, with LLMs at this moment deciding who lives and dies - probably should try and take the right lesson from fiction. For once.
Economists have effectively become a priestly class, dressing up the ruling ideology in "science-y" robes so as to communicate authority. All social sciences are at risk of doing so, but they fall right into this hole the instant that they don't perceive the world as it exists.
A trained economist either sells out to the Overlords or he gets a job as a barkeep. Or he ends up as some crank in a half-forgotten nonprofit somewhere. There's no middle ground.
Human intelligence is a remarkable adaptation, but "tendency towards delusion" might be the decidedly maladaptive trait that comes with it.
Not pass even the most modest hint towards DFARS/NIST standards. You couldn't run that loosey goosey even in just vanilla medical manufacturing. I challenge what their definition of "sandbox" actually is, apart from the basal "designated software/runtime environment"
Israeli "Lavender" AI-assisted targeting was used with/in "Where's Daddy"[1] mode, which had several frameworks for using family to strike identified targets. One method is to liquidate the residence with maximum family members on prem, which had a high chance of drawing the target to the location where a second strike would have a high chance of lethality.
One aspect of Lavender that proved frustrating: the system identified so many targets that exasperated ground controllers eventually just ordered the equivalent of full on carpet bombing. When the whole building's showing up as red on your computer screen, I suppose that makes sense. From a particular perspective.
[1] I'm . . uh . . not making that up. That what is/was called. Undoubtedly it has a more digestible name now.
About ten years ago I went with text-based graph description languages and haven't looked back[1].
One application of AI I have found useful is in the quick composition of graphs via text-based graph description languages: graphviz (the great granddaddy), mermaid.js, plantuml, and of course derivatives like WireViz and CircuiTikZ.
A typical ask would be something like "generate a mermaid network diagram showing the relationships of all markup languages". It's surprisingly good.
A neat trick you can do if writing in Asciidoc: conditional directives are pre-processor directives, which means they're interpreted before the graphing engine goes to work. So you can make art that has sections which can toggle on and off based on document variables (the Asciidoc lingo for these is "attributes" but using that word can be confusing for old XML hands). Very neat when you have a block diagram you want to reuse for lots of different configurations.
[1] Unless I need 3d, in which case I'm afraid I like Blender a lot. Even more than Asciidoc.
The immediate response to the 10/7 infiltration attack was extremely lethal to Israelis as well, something not well covered outside of Israeli media.
28 helicopters emptied their internal stores of 30mm autocannon and Hellfires that day, with many RTB to rearm/refuel, all of them at dense Israeli territory. Seven of them dumped their entire stores into Moshav Tkuma. To this day all deaths there are tallied to the infiltrators, with the exception of Efrat Katz. Rapid bulldozer burial of damaged vehicles and buildings was also performed, as the damage from those weapons is very distinctive. Not a gesture of honesty, that.
Tanks were also instructed to fire their main armament into houses known to have civilians inside. Israeli corpses were, again, tallied to infiltrators; any non-Israeli corpses tallied as hostile.
Pilots, soldiers, tankists, and UAS operators all asked over the radio for targets that day, but were simply directed to apply maximal fires to anything that moved in a Palestinian-like way. Hannibal was cited as justification. The Israeli Hannibal operational order, which directs the use of force to prevent soldiers being taken into captivity, was apparently being cited over the air to justify the deaths of civilians. An extreme distortion, but one which Israelis are increasingly making their peace with, alongside many others.
Friendly fire was a rarity and extreme minority of deaths on October 7th. Perhaps dozens out of 1200 that day. If the pilots haven't done anything realistically more civilians would have died. Do you have a better way of handling an invasion of thousands of people who came to kill and kidnap?
And this btw also goes the other direction - Hamas killed himself many Gazans either by mistake (missile falls in the wrong place) or on purpose; they are all counted as deaths by the IDF.
The conspiracy is lying and that it was more than it actually was to downplay the hamas deaths. Re-read the comment I replied two and look at the way its worded "The immediate response to the 10/7 infiltration attack was extremely lethal to Israelis as well", "28 helicopters emptied their internal stores of 30mm autocannon and Hellfires that day, with many RTB to rearm/refuel, all of them at dense Israeli territory Seven of them dumped their entire stores into Moshav Tkuma." there was 1 death by helicopter when a hamas truck was shot and there was an isreali hostage inside unknown to the pilot. There is no evidence to support the conspiracy that they were mag dumping everything that moved.
"Tanks were also instructed to fire their main armament into houses known to have civilians inside. Israeli corpses were, again, tallied to infiltrators; any non-Israeli corpses tallied as hostile.". There is no evidence they were instructed to do this and there is only one instance of tank fire killing isreali's and it was due to unknown hostages inside the house.
The entire response was within reason for what you'd expect but the iran propaganda network works hard to spin the narrative and create doubt and weave conspiracy.
These supports my argument more than yours. You are posting confirmation of what im saying and articles that are speculation and out of context quotes or complete rejections of the claims you are making.
"Giant Metal Things Hucked Through the Air Across Ocean" are of a quantitatively higher risk profile than "New Computer Thing", no matter how you slice that particular salami.
If you tossed the aviation regulatory framework out the window, you have maybe ten years before aviation reverts to high end hobbyists[1], due to the escalating risk profile.
No, it'll come down to blood once more. With thermonuclear explosives the de-industrialization will be even more complete than it was for Eastern Europe the last go round.
Both of those are expensive as hell, by the way.
Cooling via radiation follows Stefan–Boltzmann: P = εσAT⁴. Let's assume a good surface (emissivity ~0.9) at 300 K (27 °C) at 400 W per square meter per side. A flat panel radiating from both faces into deep space gets 800 W/m, not including the losses from, say, the Sun, or from IR coming off the Earth. Now, input power. Sunlight in orbit ~1,360 W/m², assume ~22% cell efficiency, we got 300 W/m². So each 1 MW compute, 3,300 m² of solar panel and minimum 1,200–1,500 m² of radiator.
In case ya didn't know - 1 MW is tiny from a present-day-datacenter perspective. It's like 8 racks. So we're talking orbital megastructures here, many many many square kilometers, and this is with all the best case assumptions, and magic radiator panels that never see the sun, or the earth, or the moon.
This is just the basic numbers here, by the way. There's a garbage truck full of other unsolvable problems if you poke your head in there.
Aside from the "Avoid Regulations" aspect, and the "Everything That Burns Deorbiting is Depreciation" aka "The Starlink Trick", I'm not sure what the hell the draw is.
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