GlenTheMachine
today at 2:46 AM
Space roboticist here.
As with a lot of things, it isn't the initial outlay, it's the maintenance costs. Terrestrial datacenters have parts fail and get replaced all the time. The mass analysis given here -- which appears quite good, at first glance -- doesn't including any mass, energy, or thermal system numbers for the infrastructure you would need to have to replace failed components.
As a first cut, this would require:
- an autonomous rendezvous and docking system
- a fully railed robotic system, e.g. some sort of robotic manipulator that can move along rails and reach every card in every server in the system, which usually means a system of relatively stiff rails running throughout the interior of the plant
- CPU, power, comms, and cooling to support the above
- importantly, the ability of the robotic servicing system toto replace itself. In other words, it would need to be at least two fault tolerant -- which usually means dual wound motors, redundant gears, redundant harness, redundant power, comms, and compute. Alternately, two or more independent robotic systems that are capable of not only replacing cards but also of replacing each other.
- regular launches containing replacement hardware
- ongoing ground support staff to deal with failures
The mass analysis also doesn't appear to include the massive number of heat pipes you would need to transfer the heat from the chips to the radiators. For an orbiting datacenter, that would probably be the single biggest mass allocation.
I've had actual, real-life deployments in datacentres where we just left dead hardware in the racks until we needed the space, and we rarely did. Typically we'd visit a couple of times a year, because it was cheap to do so, but it'd have totally viable to let failures accumulate over a much longer time horizon.
Failure rates tend to follow a bathtub curve, so if you burn-in the hardware before launch, you'd expect low failure rates for a long period and it's quite likely it'd be cheaper to not replace components and just ensure enough redundancy for key systems (power, cooling, networking) that you could just shut down and disable any dead servers, and then replace the whole unit when enough parts have failed.
rajnathani
today at 9:56 AM
Exactly what I was thinking when the OP comment brought up "regular launches containing replacement hardware", this is easily solvable by actually "treating servers as cattle and not pets" whereby one would simply over-provision servers and then simply replace faulty servers around once per year.
Side: Thanks for sharing about the "bathtub curve", as TIL and I'm surprised I haven't heard of this before especially as it's related to reliability engineering (as from searching on HN (Algolia) that no HN post about the bathtub curve crossed 9 points).
serious q: how much extra failure rate would you expect from the physical transition to space?
on one hand, I imagine you'd rack things up so the whole rack/etc moves as one into space, OTOH there's still movement and things "shaking loose" plus the vibration, acceleration of the flight and loss of gravity...
Coffeewine
today at 10:56 AM
It would be interesting to see if the failure rate across time holds true after a rocket launch and time spent in space. My guess is that it wouldnât, but thatâs just a guess.
I think it's likely the overall rate would be higher, and you might find you need more aggressive burn-in, but even then you'd need an extremely high failure rate before it's more efficient to replace components than writing them off.
NitpickLawyer
today at 5:18 AM
Appreciate the insights, but I think failing hardware is the least of their problems. In that underwater pod trial, MS saw lower failure rates than expected (nitrogen atmosphere could be a key factor there).
> The company only lost six of the 855 submerged servers versus the eight servers that needed replacement (from the total of 135) on the parallel experiment Microsoft ran on land. It equates to a 0.7% loss in the sea versus 5.9% on land.
6/855 servers over 6 years is nothing. You'd simply re-launch the whole thing in 6 years (with advances in hardware anyways) and you'd call it a day. Just route around the bad servers. Add a bit more redundancy in your scheme. Plan for 10% to fail.
That being said, it's a complete bonkers proposal until they figure out the big problems, like cooling, power, and so on.
Indeed, MS had it easier with a huge, readily available cooling reservoir and a layer of water that additionally protects (a little) against cosmic rays, plus the whole thing had to be heavy enough to sink. An orbital datacenter would be in a opposite situation: all cooling is radiative, many more high-energy particles, and the weight should be as light as possible.
looofooo0
today at 9:27 AM
Power!? Isnt that just PV and batteries? LEO has like 1.5h orbit.
literalAardvark
today at 10:45 AM
It's a Datacenter... I guess solar is what they're planning to use, but the array will be so large it'll have its own gravity well
protocolture
today at 3:23 AM
Did Microsoft do any of that with their submersible tests?
My feeling is that, a bit like starlink, you would just deprecate failed hardware, rather than bother with all the moving parts to replace faulty ram.
Does mean your comms and OOB tools need to be better than the average american colo provider but I would hope that would be a given.
protocolture
today at 3:35 AM
>The mass analysis also doesn't appear to include the massive number of heat pipes you would need to transfer the heat from the chips to the radiators. For an orbiting datacenter, that would probably be the single biggest mass allocation.
And once you remove all the moving parts, you just fill the whole thing with oil rather than air and let heat transfer more smoothly to the radiators.
MadnessASAP
today at 6:23 AM
Oil, like air, doesn't convent well in 0G, you'll need pretty hefty pumps and well designed layouts to ensure no hot spots form. Heat pipes are at least passive and don't depend on gravity.
Mineral oil density is around 900kg / cubic meter.
Not sure this is such a great idea.
Does using oil solve the mass problem? Liquids aren't light.
protocolture
today at 6:05 AM
I would wager that its lighter than:
Repair robots
Enough air between servers to allow robots to access and replace componentry.
Spare componentry.
An eject/return system.
Heatpipes from every server to the radiators.
littlestymaar
today at 5:57 AM
First, oil is much heavier than air.
Second: you still need radiators to dissipate heat that is in oil somehow.
Spooky23
today at 11:47 AM
Donât you need to look at different failure scenarios or patterns in orbit due to exposure to cosmic rays as well?
It just seems funny, I recall when servers started getting more energy dense it was a revelation to many computer folks that safe operating temps in a datacenter should be quite high.
Iâd imagine operating in space has lots of revelations in store. Itâs a fascinating idea with big potential impact⊠but I wouldnât expect this investment to pay out!
monster_truck
today at 3:53 AM
I suspect they'd stop at automatic rendezvous & docking. Use some sort of cradle system that holds heat fins, power, etc that boxes of racks would slot into. Once they fail just pop em out and let em burn up. Someone else will figure out the landing bit
I won't say it's a good idea, but it's a fun way to get rid of e-waste (I envision this as a sort of old persons home for parted out supercomptuers)
closewith
today at 5:55 AM
Spreading heavy metals in the upper atmosphere. Fun.
garbagewoman
today at 8:15 AM
seems to be an industry standard
oceanplexian
today at 3:45 AM
Why does it need to be robots?
On Earth we have skeleton crews maintain large datacenters. If the cost of mass to orbit is 100x cheaper, itâs not that absurd to have an on-call rotation of humans to maintain the space datacenter and install parts shipped on space FedEx or whatever we have in the future.
If you want to have people you need to add in a whole lot of life support and additional safety to keep people alive. Robots are easier, since they don't die so easily. If you can get them to work at all, that is.
Life support can be on the shuttle/transport. Or it can be its own hab⊠space office ? Space workshop ?
monster_truck
today at 3:57 AM
That isn't going to last for much longer with the way power density projections are looking.
Consider that we've been at the point where layers of monitoring & lockout systems are required to ensure no humans get caught in hot spots, which can surpass 100C, for quite some time now.
Robotbeat
today at 4:39 AM
You mean like every single kitchen?
Robotbeat
today at 4:39 AM
Bingo.
It's all contingent on a factor of 100-1000x reduction in launch costs, and a lot of the objections to the idea don't really engage with that concept. That's a cost comparable to air travel (both air freight and passenger travel).
(Especially irritating is the continued assertion that thermal radiation is really hard, and not like something that every satellite already seems to deal with just fine, with a radiator surface much smaller than the solar array.)
It is really hard, and it is something you need to take into careful consideration when designing a satellite.
It is really fucking hard when you have 40MW of heat being generated that you somehow have to get rid of.
HPsquared
today at 9:43 AM
It's all relative. Is it harder than getting 40MW of (stable!) power? Harder than packaging and launching the thing? Sure it's a bit of a problem, perhaps harder than other satellites if the temperature needs to be lower (assuming commodity server hardware) so the radiator system might need to be large. But large isn't the same as difficult.
Musk is already in the testing phase for this. His starship rockets should be reusable as soon as 2018!
Nevermark
today at 5:50 AM
And in the meantime, he has responsibly redistributed and recycled their mass. Avoiding any concern that Earth's mass could be negatively impacted.
How will he overtake all the other reusable rockets at this rate?
Yeah, just attach a Haven module to the data center.
It sounds like building it on the moon would be better.
hamburglar
today at 3:11 AM
Seems prudent to achieve fully robotic datacenters on earth before doing it in space. I know, Iâm a real wet blanket.
HPsquared
today at 9:45 AM
The economics don't work the same on earth.
andreasmetsala
today at 11:38 AM
What makes the economics better in space?
Are there any unique use-cases waiting to be unleashed?
HPsquared
today at 11:45 AM
Regular maintenance methods are cheap on earth and infeasible in space.
Keep in mind economics is all about allocation of scarce resources with alternative uses.
Robotbeat
today at 4:35 AM
If mass is going to be as cheap as is needed for this to work anyway, there's no reason you can't just use people like in a normal datacenter.
littlestymaar
today at 6:01 AM
Space is very bad for the human body, you wouldn't be able to leave the humans there waiting for something to happen like you do on earth, they'd need to be sent from earth every time.
Also, making something suitable for humans means having lots of empty space where the human can walk around (or float around, rather, since we're talking about space).
switknee
today at 12:10 PM
Underwater welder, though being replaced by drone operator, is still a trade despite the health risks. Do you think nobody on this whole planet would take a space datacenter job on a 3 month rotation?
I agree that it may be best to avoid needing the space and facilities for a human being in the satellite. Fire and forget. Launch it further into space instead of back to earth for a decommission. People can salvage the materials later.