Comment by CGMthrowaway
11 hours ago
There's clearly rhetorical hyperbole happening there. But assuming that thermal rejection is good in space, & launch costs continue falling, as earth-based data centers become power/grid-constrained, there is a viable path for space power gen.
The craziest part of those statements is "100 kW per ton." IDK what math he is doing there or future assumptions, but today we can't even sniff at 10 kW per ton. iROSA [1] on the ISS is about 0.150 kW per ton.
[1]https://en.wikipedia.org/wiki/Roll_Out_Solar_Array
edit: iROSA = 33 kW per ton, thanks friends
Not to be an Elon defender, but can you back up your 0.15/ton? My own searching puts ROSA orders of magnitude higher. Each array is 600kg (0.6t) and puts out 20kw (https://space.skyrocket.de/doc_sdat/irosa-1.htm) which makes 20/0.6 = 33.333 kw/ton
You're right, my fault. I made an math booboo somewhere. Your calc seems right
Hey all good. My advice, not that you asked for it, is to put the math in the comment. Even as a footnote. I've found myself backtracking a lot of math comments after I stare at it in the text box for a few seconds.
The company lists their ISS solar panels as 28 kW for 331 kg, which comes pretty near to 100 W/kg.
Company website:
https://rdw.com/wp-content/uploads/2023/06/redwire-roll-out-...
And their Opal configuration beats the metric: 5.3 kW for 42.7 kg.
Okay so that works out to 124 kW/ton for the opal config.
Maybe I'm just out of the loop, but is solar substantially more efficient in space? I assume the satellites won't orbit in a way that follows the sun. And presumably the arrays of panels they can attach to a satellite don't exceed the size of the panels you could slap on and around a data center (at least without being insanely expensive).
Yeah the main benefits are:
1. solar is very efficient at generating energy, no moving parts, simple physics etc.
2. in space you don't deal with weather or daylight cycle, you can just point your panels at the sun and generate very stable energy, no batteries required
3. environmental factors are simpler, no earthquakes, security, weather. Main problem here is radiation
In theory its a very elegant way to convert energy to compute.
2 is wrong. At a Lagrange point you can do this. Not in low earth orbit - in LEO sunset is every 60 minutes or so, and you spend the next 60 minutes in darkness.
Satellites are heavily reliant on either batteries or being robust to reboots, because they actually do not get stable power - it's much more dynamic (just more predictable too since no weather).
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> But assuming that thermal rejection is good in space
Don't assume this. Why would you assume this?
Just put a slightly larger solar array on the same equipment on earth?
> put a slightly larger solar array on the same equipment on earth?
Land and permitting. I’m not saying the math works. Just that there are envelopes for it to.
There is practically infinite land in which to build a datacenter.
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The math literally works.
The US mandates by law that we grow a fuck ton of corn to mix 10% ethanol into gasoline.
If you replaced just those cornfields with solar/wind, they would power the entire USA and a 100% electric vehicle fleet. That includes the fact that they are in the corn belt with less than ideal sun conditions.
We aren’t even talking about any farmland that produces actual food or necessary goods, just ethanol as a farm subsidy program.
The US is already horrendously bad at land use. There’s plenty of land. There’s plenty of ability to build more grid capacity.
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Solar in space is a very different energy source in terms of required infrastructure. You don't need batteries, the efficiency is much higher, cooling scales with surface area (radiative cooling doesn't work as well through an atmosphere vs. vacuum), no weather/day cycles. Its a very elegant idea if someone can get it working.
Only if you also disregard all the negatives.
The panels suffer radiation damage they don't suffer on Earth. If this is e.g. the same altitude orbits as Starlink, then the satellites they're attached to burn up after around tenth of their ground-rated lifetimes. If they're a little higher, then they're in the Van Allen belts and have a much higher radiation dose. If they're a lot higher, the energy cost to launch is way more.
If you could build any of this on the moon, that would be great; right now, I've heard of no detailed plans to do more with moon rock than use it as aggregate for something else, which means everyone is about as far from making either a PV or compute factory out of moon rock as the residents of North Sentinel Island are.
OK, perhaps that's a little unfair, we do actually know what the moon is made of and they don't, but it's a really big research project just to figure out how to make anything there right now, let alone making a factory that could make them cost-competitive with launching from Earth despite the huge cost of launching from Earth.
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Sun-synchronous orbit means there's no nightime for satellites in that orbit.
"There's clearly rhetorical hyperbole happening there" in a business paper is called lying
Name a unicorn whose early round pitch decks are 100% free of wishful thinking
Elon is a pathological liar and it’s crazy that he still gets sanewashed after all he’s done. It’s insanity that he hasn’t been kicked out of leading his companies, and it’s also insanity that he hasn’t been prosecuted by the SEC.
You’ve spent too much life force trying to even understand the liar’s fake logic.
Let’s start right here: there is no such thing as becoming power/grid constrained on earth. If you replaced just the cornfields that the United States uses just to grow corn for ethanol in gasoline just in the corn belt, you could power the entire country with solar+batteries+wind. Easily, and cheaply.
If you don’t even believe that solar+batteries are cheap (they are), fine, choose your choice of power plant. Nuclear works fine.
The truth is, xAI combining with SpaceX is almost certainly corrupt financial engineering. SpaceX as a government contractor and that means Elon’s pal Trump can now siphon money into xAI via the federal government.
>SpaceX as a government contractor and that means Elon’s pal Trump can now siphon money into xAI via the federal government.
I wonder how much faith Musk has that the US will never again have a president and/or Congress willing to torpedo such an incestuous deal.