Summarizer

5 to 7 months given they want 100kw Per ton and magical mystery sauce shielding is going to do shit all.

not to mention that radiation hardening of chips has a big impact on cost and performance

You could immersion cool them and get radiation resistance as a bonus.

Right up to the radiation limit and then you'll either have to throttle your precious GPUs or you'll be melting your satellite or at least the guts of it. You're looking at an absolutely massive radiator here, many times larger than the solar panels that collect the energy to begin with.

You have not done any real world verification on any of this, you are arguing from a very flawed and overly simplistic lay-persons theoretical model of how solar panels must function in space and then you draw all kinds of conclusions from that model, none of which have been born out by experiment. 25% efficiency for a solar panel means that 25% of the sunlight incident on a panel was turned into electricity. It has nothing to do with how big a fraction is turned into heat, though obviously the more of it is turned into electricity the less there is available to be converted into heat. And it does not account for other parts of the spectrum that are outside of the range that the panel can capture. That 25% is peak efficiency. It does not take into account: (1) the temperature of the panel (higher temp->lower efficiency), hence the need for passive cooling of the panels in space due to a lack of working fluid (air). (2) the angle of the incidence: both angles have to be 'perfect' for that 25% to happen, which in practice puts all kinds of constraints on orientation, especially when coupled with requirements placed on the rest of the satellite. (3) the effects of aging (which can be considerable, especially in space), for instance, due to solar wind particles, thermal cycling and so on (4) the effect of defects in the panels causing local failure that can cascade across strings of cells and even strings of panels (5) the effects of the backing and the glass (6) in space: the damage over time due to mechanical effects of micro meteorite impact on cells and cover; these can affect the panels both mechanically and electrically To minimize all of these effects (which affect both operational life span of panels as well as momentary yield) and effectively to pretend they do not exist is proof that you are clueless, and yet you make these (loud) proclamations. Gell-Mann had something to say about this, so now your other contributions suffer from de-rating.

Also solar wind, cosmic rays etc. We don't have perfect shielding for that yet. Cooling would be tricky and has to be completely radiative which is very slow in space. Vacuum is a perfect insulator after all, look how thermos work.

There are a class of people who may seem smart until they start talking about a subject you know about. Hank Green is a great example of this. For many on HN, Elon buying Twitter was a wake up call because he suddenly started talking about software and servers and data centers and reliability and a ton of people with experience with those things were like "oh... this guy's an idiot". Data centers in space are exactly like this. Your comment (correctly) alludes to this. Companies like Google, Meta, Amazon and Microsoft all have so many servers that parts are failing constantly. They fail so often on large scales that it's expected things like a hard drive will fail while a single job might be running. So all of these companies build systems to detect failures, disable running on that node until it's fixed, alerting someone to what the problem is and then bringing the node back online once the problem it's addressed. Everything will fail. Hard drives, RAM, CPUs, GPUs, SSDs, power supplies, fans, NICs, cables, etc. So all data centers will have a number of technicians who are constantly fixing problems. IIRC Google's ratio tended to be about 10,000 servers per technician. Good technicians could handle higher ratios. When a node goes offline it's not clear why. Techs would take known good parts and basically replacce all of them and then figure out what the problem is later, dispose of any bad parts and put tested good parts into the pool of known good parts for a later incident. Data centers in space lose all of this ability. So if you have a large number of orbital servers, they're going to be failing constantly with no ability to fix them. You can really only deorbit them and replace them and that gets real expensive. Electronics and chips on satellites also aren't consumer grade. They're not even enterprise grade. They're orders of magnitude more reliable than that because they have to deal with error correction terrestial components don't due to cosmic rays and the solar wind. That's why they're a fraction of the power of something you can buy from Amazon but they cost 1000x as much. Because they need to last years and not fail, something no home computer or data center server has to deal with. Put it this way, a hardened satellite or probe CPU is like paying $1 million for a Raspberry Pi. And anybody who has dealt with data centers knows this.

First of all Twitter had basically no downtime since he bought it, so all the 'internet experts' posting their thoughts were completely dead wrong. If anything Twitter was far more reliable than Microsoft has been these past few years. You are assuming things need to run the same way in space, for instance you mentioned fans, you won't have any in space. You also won't have any air, dust, static, or any moving parts. You are assuming the costs to launch to orbit are high, when the entire point of Spacex's latest ship is to bring the cost to launch so low that it is cheaper per ton than an airplane flight. Maintenance would be nice but you are saying this like Elon Musk's company doesn't already manage the most powerful datacenters on the planet. You have no clue what you are talking about regarding cosmic rays and solar wind, these will literally be solar powered and behind panels and shielding 100% of the time.

Have you heard of cosmic radiation?

Cosmic rays take time to destroy them.

It's not only about destruction. It's also about reliability. Without proper shielding and error correction you're going to have lots and lots of reliability issues and data corruption. And if we're talking about AI and given the current reliability problems of the Nvidia hardware, plus the radiation, plus the difficulty for refrigerating all that stuff on space... That's a big problem. And we still haven't started to talk about the energy generation. I think there's a very interesting use case on edge computing (edge of space, if you wanna make the joke) that in fact some satellites are already doing, were they preprocess data before sending back to Earth. But datacenter-power-level computing is not even near. I have no idea and numbers to back it up, but I feel it would be even easier to set up a Moon datacenter than an orbital datacenter (when talking about that size of datacenter)

Maintaining modern accelerators requires frequent hands-on intervention -- replacing hardware, reseating chips, and checking cable integrity. Because these platforms are experimental and rapidly evolving, they aren't 'space-ready.' Space-grade hardware must be 'rad-hardened' and proven over years of testing. By the time an accelerator is reliable enough for orbit, it’s several generations obsolete, making it nearly impossible to compete or turn a profit against ground-based clusters.

Thank you. The waste heat problem is so bad but no one gets around to mentioning the fact that you can't have AI grade chips and space at the same time.

Not only the sibling comments points, but cars aren't exposed to the radiation of space...

Not to mention… how do you repair it when components fail, especially sensitive electronics against cosmic radiation