YC company announces a giant data center in space
Startup Twitter: Makes so much sense, it will be so easy to cool in space!
Space Twitter: How the hell are they proposing to keep it cool??
> As launch costs fall, orbital data centers will leverage 24/7 solar energy and _passive cooling_, rapidly deploying to gigawatt-scale, avoiding permitting constraints on Earth.
It sounds like they want to use copper heatspreaders and radiators to dump gigawatts into space. From those little pods connected to the spine... without any active cooling components
Oh dear.
There are many SSO's for all the times of the day, most SSO's are not permantly in sunlight.
The comment I replied to implied that any old SSO would have the property of being always in the sunlight, this isn't true.
The particular issue with a terminator SSO is that region will get crowded (sure, space is large) and one collision will seed debris to spoil it for everyone for some time.
> Riding the terminator is useful for active radar satellites ..
All sats need some level of power or another, not all want to ride the terminator, see (for one example)
https://modis.gsfc.nasa.gov/about/
in which different sats in the constellation travel at different times of day (why?).
I only skimmed the linked PDF but did they write anything about the risks or challenges of deploying consumer hardware into space? Is space-hardened hardware not required?
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There’s really no such thing as active cooling in space. You can move the heat from the component to the radiators with pumped water but ultimately the only way to get rid of heat in space is passively radiating it away.
And it’s very inefficient at removing heat unless there’s a large temperature differential. If the radiator heats up to 70C it can dissipate 785 watts per square meter of area facing into space. I guess assuming you have a front and also a back of a panel both radiating equally that could be 1570W per square meter of panel material. You can check it yourself with this equation: https://courses.lumenlearning.com/suny-physics/chapter/14-7-....
So for this “1 gigawatt” project you’d need 0.6 million square meters of double-sided radiators. Which is about the area of the Pentagon, or a quarter the area of Monaco. It would weigh around 6000 metric tons, which is the weight of half the trash produced in NYC in a day. This would require up to 300 Falcon Heavy launches for a total launch cost of $30 billion.
They say the launch cost for one 40MW unit (including radiators! and solar panels! and radiation shielding!) will be $5 million. That’s pretty laughable as just 25 of these 40MW units = 1GW. And 1/25 of $30 billion is … well over $1 billion.
Somehow, I estimate that JUST THE COOLING RADIATORS will cost >$1 billion to put into space. But they estimate they can put the whole everything in space for less than 0.5% of a very reasonable estimate.
EDIT: Actually, just launching enough H100’s to consume 40MW would cost at least $200 million. One H100 uses 700W so you’d need 57,000 of them to consume 40MW. Each H100 weighs 1.7kg so thats a total of 97 metric tons of H100’s. The falcon heavy can launch between 20-64 metric tons so you’ll need two launches at $100 million per launch.