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I saw a few posts about this and thought it was a joke. This tweet sums it up: YC company announces a giant data center in space Startup Twitter: Makes so muc
by slyall 2y ago
I saw a few posts about this and thought it was a joke. This tweet sums it up:
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??
https://x.com/mouthofmorrison/status/1831680658927669632 https://x.com/mouthofmorrison/status/1831680658927669632
- CobrastanJorji 2y agoWait, was this not a joke? I thought this was one of those "let's realistically think through the implications of trying to live on a space tortoise" kind of papers.
- throwup238 2y agoBut their video is so pretty! https://www.lumenorbit.com/ https://www.lumenorbit.com/ > 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.
- hollerith 2y agoWhat manner of active cooling do you imagine might work in vacuum? Fans?
- geysersam 2y agoPipes with a coolant?
- deleted 2y ago[deleted]
- dkbrk 2y agoYou use radiation for cooling in space. That obeys the Stefan-Boltzmann law with power scaling with T^4 (so you want the radiators as hot as possible). You can use passive elements, like heat-pipes to move heat to the radiators, but active elements like pumps for forced convection could make sense; and most importantly heat pumps are an active element that can boost the temperature of the radiators vs the thing you're keeping cool (thereby increasing the heat rejection capacity of a given radiator size).
- hollerith 2y agoThanks.
- deleted 2y ago[deleted]
- atoav 2y agoPicture of a radiator on the ISS in this thread: https://physics.stackexchange.com/questions/149832/cooling-a-satellite https://physics.stackexchange.com/questions/149832/cooling-a...
- hollerith 2y agoThanks. Since (like the answer by a "Fluid/Thermal Engineer" with a PhD says) the ISS uses mechanically-pumped fluid loops to transfer the heat to radiators, certainly a server farm in space (with its much higher energy density) should, too, rather than relying on a simpler, but less efficient passive-cooling design in which heat gradients cause the convection or movement of the fluid -- and ISTR reading that heat gradients don't even cause convection in the absence of gravity.
- reaperman 2y agoEdit: Apparently while SpaceX launches currently cost $100 million, some people expect them to offer Starship launches for $1-4 million sometime in the future. If SpaceX really can reduce their launch prices by 99% then things might actually be napkin-math economically feasible. ———————- 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-radiation/#:~:text=The%20rate%20of%20heat%20transfer%20depends%20on%20the%20surface%20area,the%20emissivity%20of%20the%20body 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.
- raverbashing 2y agoYeah There's one cool way of "passively cooling energy into space" from Earth Build your datacenters in a cold place with clear skies and train at night.
- causality0 2y agoSo did these people get into YC with a smart idea which they dropped in favor of this idiotic one, or did all the smart people at YC call in sick the day this company was accepted? Because dayum.
- ASalazarMX 2y ago"It was not impossible to build the Space Data Center (TM) in the vacuum of space. It was impossible to build it anywhere else."