What kind of the problem you're talking about compared to existing satellites? That is, all existing satellites generate power, and need to dissipate that power, and most of it goes to waste heat, and the satellites somehow do that successfully - what is the specific problem you're talking about, which can't be solved by the same means?
The numbers matter. The thermal budget a satellite is an tightly controlled thing. Large modern ones are in the order of a few to a couple of 10s of kilowatts, so something like a few to several low 10s of modern GPU compute power. Even with thousands of yet to be designed or launched satellites, it's going to have trouble competing with even a single current DC, plus it is in SAPCE for some reason, so everything is more expensive for lots of reasons.
> it's going to have trouble competing with even a single current DC
This looks like a valid argument to me, yes. Elon mentioned 1,000,000 satellites - I'm thinking about 3rd version of Starlink as a typical example, 2 tons, 60 satellites per Starship launch, 16,000 Starship launches for the constellation, comparing with 160 launches per year of today's Falcon 9...
The argument about problems of dissipating heat still stands - I don't see a valid counterargument here. Also "SAPCE" problem looks different from the point of view of this project - https://www.50dollarsat.info/ . Basically, out launch costs go way down, and quality of electronics and related tech today on Earth is high enough to work on LEO.
Even the buses for giant communications satellites are still at the single digit kilowatt scale. The current state of the art in AI datacenters is 500+ kw per rack.
So you're talking about an entirely different scale of power and needed cooling.
The reason we dont have a lot of compute in space, is because of the heat issue. We could have greater routing density on communication satellites, if we could dissipate more heat. If Starlink had solved this issue they would have like triple the capacity and could just drop everything back to the US (like their fans think they do) rather than trying to minimise the number of satellites traffic passes through before exiting back to a ground station usually in the same country as the source. In fact, conspiratorially, I think thats the problem he wants to solve. Because wet dreams of an unhindered, unregulated, space internet are completely unanswered in the engineering of Starlink.
I have actually argued this from the other side, and I reckon space data centres are sort of feasible in a thought experimental sense. I think its a solvable problem eventually. But heat is the major limiting factor and back of the napkin math stinks tbh.
IIRC the size/weight of the satellite is going to get geometrically larger as you increase the compute size due to the size of the required cooling system. Then we get into a big argument about how you bring the heat from the component to the cooling system. I think oil, but its heavy again, and several space engineering types want to slap me in the face for suggesting it. Some rube goldberg copper heatpipe network through atmosphere system seems to be preferred.
I feel like, best case, its a Tesla situation, he clears the legislative roadblocks and solves some critical engineering problem by throwing money at it, and then other, better people step in to actually do it. Also triple the time he says it will take to solve the problem.
And then, ultimately, as parts fail theres diminishing returns on the satellite. And you dont even get to take the old hardware to the secondary market, it gets dropped in the ocean or burnt up on reentry.
Principally speaking, as much energy as satellite receives from solar panels it needs to send away - and often a lot of it is in the form of heat. So, the question is, how much energy is received in the first place. We currently have some quarter of megawatt of solar panels of ISS, so in principal - in principal - we know how to do this kind of scale per satellite. In practice we perhaps will have more smaller satellites which together aggregate the compute to the necessary lever and power to the corresponding level.
> We currently have some quarter of megawatt of solar panels of ISS
It's average outbut is like half of that though. So something the size of the space station, a massive thing which is largely solar panels and radiators, can do like 120kW sustained. Like 1-2 racks of GPUs, assuming you used the entire power budget on GPUs.
And we're going to build and launch millions of these.
The ISS's radiators weigh thousands of kilograms to radiate around 70 KW. He's talking about building data centers in space in the GW range.
Assuming he built this in LEO (which doesn't make sense because of atmospheric drag), and the highest estimates for what starship could one day deliver to LEO (200 metric tons), and only 1 metric ton of radiators per 100KW, that's 50 launches just to carry up the radiators.
What kind of the problem you're talking about compared to existing satellites? That is, all existing satellites generate power, and need to dissipate that power, and most of it goes to waste heat, and the satellites somehow do that successfully - what is the specific problem you're talking about, which can't be solved by the same means?
The numbers matter. The thermal budget a satellite is an tightly controlled thing. Large modern ones are in the order of a few to a couple of 10s of kilowatts, so something like a few to several low 10s of modern GPU compute power. Even with thousands of yet to be designed or launched satellites, it's going to have trouble competing with even a single current DC, plus it is in SAPCE for some reason, so everything is more expensive for lots of reasons.
> it's going to have trouble competing with even a single current DC
This looks like a valid argument to me, yes. Elon mentioned 1,000,000 satellites - I'm thinking about 3rd version of Starlink as a typical example, 2 tons, 60 satellites per Starship launch, 16,000 Starship launches for the constellation, comparing with 160 launches per year of today's Falcon 9...
The argument about problems of dissipating heat still stands - I don't see a valid counterargument here. Also "SAPCE" problem looks different from the point of view of this project - https://www.50dollarsat.info/ . Basically, out launch costs go way down, and quality of electronics and related tech today on Earth is high enough to work on LEO.
Even the buses for giant communications satellites are still at the single digit kilowatt scale. The current state of the art in AI datacenters is 500+ kw per rack.
So you're talking about an entirely different scale of power and needed cooling.
I mean you have this around the wrong way.
The reason we dont have a lot of compute in space, is because of the heat issue. We could have greater routing density on communication satellites, if we could dissipate more heat. If Starlink had solved this issue they would have like triple the capacity and could just drop everything back to the US (like their fans think they do) rather than trying to minimise the number of satellites traffic passes through before exiting back to a ground station usually in the same country as the source. In fact, conspiratorially, I think thats the problem he wants to solve. Because wet dreams of an unhindered, unregulated, space internet are completely unanswered in the engineering of Starlink.
I have actually argued this from the other side, and I reckon space data centres are sort of feasible in a thought experimental sense. I think its a solvable problem eventually. But heat is the major limiting factor and back of the napkin math stinks tbh.
IIRC the size/weight of the satellite is going to get geometrically larger as you increase the compute size due to the size of the required cooling system. Then we get into a big argument about how you bring the heat from the component to the cooling system. I think oil, but its heavy again, and several space engineering types want to slap me in the face for suggesting it. Some rube goldberg copper heatpipe network through atmosphere system seems to be preferred.
I feel like, best case, its a Tesla situation, he clears the legislative roadblocks and solves some critical engineering problem by throwing money at it, and then other, better people step in to actually do it. Also triple the time he says it will take to solve the problem.
And then, ultimately, as parts fail theres diminishing returns on the satellite. And you dont even get to take the old hardware to the secondary market, it gets dropped in the ocean or burnt up on reentry.
Are there many of those current satellites running gpus and actually generating lots of heat?
Principally speaking, as much energy as satellite receives from solar panels it needs to send away - and often a lot of it is in the form of heat. So, the question is, how much energy is received in the first place. We currently have some quarter of megawatt of solar panels of ISS, so in principal - in principal - we know how to do this kind of scale per satellite. In practice we perhaps will have more smaller satellites which together aggregate the compute to the necessary lever and power to the corresponding level.
> We currently have some quarter of megawatt of solar panels of ISS
It's average outbut is like half of that though. So something the size of the space station, a massive thing which is largely solar panels and radiators, can do like 120kW sustained. Like 1-2 racks of GPUs, assuming you used the entire power budget on GPUs.
And we're going to build and launch millions of these.
The ISS's radiators weigh thousands of kilograms to radiate around 70 KW. He's talking about building data centers in space in the GW range.
Assuming he built this in LEO (which doesn't make sense because of atmospheric drag), and the highest estimates for what starship could one day deliver to LEO (200 metric tons), and only 1 metric ton of radiators per 100KW, that's 50 launches just to carry up the radiators.
It’s a vacuum
Vacuum being so famous for not conducting heat that we use it to keep our coffee hot
which is why the whole idea of data centers in space is ridiculous.
I'm glad to realize we're in violent agreement, I thought you were implying cooling would be easy due to the vacuum!