Live data from Hacker News

xAI joins SpaceX

spacex.com

621–630 of 1001 posts

Re: xAI joins SpaceX

#621
post #582

Earlier quoted context omitted.

We also shouldn't overlook the fact that the proposal entirely glosses over the implication of the alternative benefits we might realize if humanity achieved the incredible engineering and technical capacity necessary to make this version of space AI happen. Think about it. Elon conjures up a vision of the future where we've managed to increase our solar cell manufacturing capacity by two whole orders of magnitude an…

This is such a hypebeast paragraph. Datacenters in space are a TERRIBLE idea. Figure out how to get rid of the waste heat and get back to me.

I agree that data centers in space is nuts.

But I think there's solutions to the waste heat issue

https://www.nasa.gov/centers-and-facilities/goddard/engineer...

Re: xAI joins SpaceX

#622

Earlier quoted context omitted.

Setting aside the possibility it's window dressing for a financial bailout, there would be two ways compute in space makes sense: 1) new technology improves vacuum heat radiation efficiency 2) new technology reduces waste heat generation from compute All the takes I've seen have been focused on #1, but I'm starting to wonder about #2... Specifically spintronics and photonic chips.

> new technology improves vacuum heat radiation efficiency Isn't this fixed by blackbody radiation equations?

That equation have surface area ? What if new material found to be extremely large surface area to weight ratio to dissipate lots of heat ?

Re: xAI joins SpaceX

#623

Either this is a straight up con, or Musk found a glitch in physics. It's extremely difficult to keep things cold in space.

This isn't really true, though? The ISS does it with radiators that are ~1/2 the area of its solar panels, and both should scale linearly with power?

Radiator size scales linearly with power but, crucially, coolant power, pumps, etc do not.

Imagine the capillary/friction losses, the force required, and the energy use(!) required to pump ammonia through a football-field sized radiator panel.

Re: xAI joins SpaceX

#624
post #360

Genuine question: is it even theoretically possible to find some way to dump the heat that would be generated by a "data center" in space?

Yes, satellites and the ISS successfully radiate heat today.

ISS solar panels only make 200kw at max.

https://taranis.ie/datacenters-in-space-are-a-terrible-horri...

It's not comparable to any data center.

Re: xAI joins SpaceX

#625
post #542

Earlier quoted context omitted.

We don’t even have a habitable structure in space when the ISS falls, there is no world in which space datacenters are a thing in the next 10, I’d argue even 30 years. People really need to ground themselves in reality. Edit: okay Tiangong - but that is not a data center.

I don't know, 10 years seems reasonable for development. There's not that much new technology that needs to be developed. Cooling and communications would just require minor changes to existing designs. Other systems may be able to be lifted wholesale with minimal integration. I think if there were obstacles to building data centers on the ground then we might see them in orbit within the next ten years. I don't see…

The same things you are saying about data centers in space was said by similar people 10-15 years ago when Elon musk said SpaceX would have a man on Mars in 10-15 years.

We have had the tech to do it since the 90's, we just needed to invest into it.

Same thing with Elon Musks hyperloop, aka the atmospheric train (or vactrain) which has been an idea since 1799! And how far has Elon Musks boring company come to building even a test loop?

Yeah, in theory you could build a data center in space. But unless you have a background in the limitations of space engineering/design brings, you don't truly understand what you are saying. A single AI data center server rack takes up the same energy load of 0.3 to 1 international space station. So by saying Elon musk can reasonable achieve this, is wild to anyone who has done any engineering work with space based tech. Every solar panel generates heat, the racks generate heat, the data communication system generates, heat... Every kW of power generated and every kW of power consumes needs a radiator. And it's not like water cooling, you are trying to radiate heat off into a vacuum. That is a technical challenge and size, the amount of tons to orbit needed to do this... Let alone outside of low earth... Its a moonshot project for sure. And like I said above, Elon musk hasnt really followed through with any of his moonshots.

Re: xAI joins SpaceX

#626

What's to stop president AOC from pulling the clearances of everyone working for SpaceX?

SpaceX launches about 60% of National Security Space Launch payloads. The only other active launcher cleared for these missions is ULA's Vulcan Centaur, which has launched 3 times total, ~once every 8 months.

And? Donald Trump's presidency has made it clear that "this is bad for our country" isn't a sufficient argument.

Re: xAI joins SpaceX

#627
post #45

> it is possible to put 500 to 1000 TW/year of AI satellites into deep space, meaningfully ascend the Kardashev scale and harness a non-trivial percentage of the Sun’s power We currently make around 1 TW of photovoltaic cells per year, globally. The proposal here is to launch that much to space every 9 hours, complete with attached computers, continuously, from the moon. edit: Also, this would capture a very trivial…

We also shouldn't overlook the fact that the proposal entirely glosses over the implication of the alternative benefits we might realize if humanity achieved the incredible engineering and technical capacity necessary to make this version of space AI happen. Think about it. Elon conjures up a vision of the future where we've managed to increase our solar cell manufacturing capacity by two whole orders of magnitude an…

Honestly, there's not a lot else I can think of if your goal is find some practical and profitable way to take advantage of relatively cheap access to near-Earth space. Communication is a big one, but Starlink is already doing that.

One of the things space has going for it is abundant cheap energy in the form of solar power. What can you do with megawatts of power in space though? What would you do with it? People have thought about beaming it back to Earth, but you'd take a big efficiency hit.

AI training needs lots of power, and it's not latency sensitive. That makes it a good candidate for space-based compute.

I'm willing to believe it's the best low-hanging fruit at the moment. You don't need any major technological advances to build a proof-of-concept. Whether it's possible for this to work well enough that it's actually cheaper than an equivalent terrestrial datacenter now or in the near future is something I can't answer.

Re: xAI joins SpaceX

#628
post #617
post #608

Earlier quoted context omitted.

Only people who never interacted with data center reliability think it's doable to maintain servers with no human intervention.

Do they need to be maintained? If one compute node breaks, you just turn it off and don't worry about it. You just assume you'll have some amount of unrecoverable errors and build that into the cost/benefit analysis. As long as failures are in line with projections, it's baked in as a cost of doing business. The idea itself may be sound, though that's unrelated to the question of whether Elon Musk can be relied on to…

AI clusters are heavily interconnected, the blast radius for single component failure is much larger than running single nodes -- you would fragment it beyond recovery to be able to use it meaningfully.

I can't get in detail about real numbers but it's not doable with current hardware by a large margin.

Re: xAI joins SpaceX

#629
This is why I come to this site. Obviously, Twitter's financials are struggling and theres more than a few people rich people who don't want to take the hit... but we can all drop that for a second to discuss the plausibility of data centers in space. Some links and comments I enjoyed:

  * https://taranis.ie/datacenters-in-space-are-a-terrible-horrible-no-good-idea/
  * https://en.wikipedia.org/wiki/Tiangong_space_station
  * "Technically challenging", a nice way to say "impossible"
  * "I’m not that smart, but if I were, I would be thinking this is an extended way to move the losses from the Twitter purchase on to the public markets."
  * "ISS radiators run on water and ammonia. Think about how much a kg costs to lift to space and you'll see the economics of space data centers fall apart real fast. Plus, if the radiator springs a leak the satellite is scrap."
  * "5,000 Starship launches to match the solar/heat budget of the 10GW "Stargate" OpenAI datacenter. The Falcon 9 family has achieved over 600 launches." [nerdsniper]
  * "No, we just "assume" (i.e. know) that radiation in a vacuum is a really bad way of dissipating heat, to the point that we use vacuum as a very effective insulator on earth."
  * "World's Best At Surfing A Temporary Hyperinflation Wave is not a life goal to really be proud of tbh"

Re: xAI joins SpaceX

#630

Earlier quoted context omitted.

what makes you believe this? radiators can be made as long as desirable within the shade of the solar panels, hence the designer can pracitically set arbitrarily low temperatures above the background temperature of the universe.

Radiators can shadow each other, so that puts some kind of limit on the size of the individual satellite (which limits the size of training run it can be used for, but I guess the goal for these is mostly inference anyway). More seriously, heat conduction is an issue: If the radiator is too long, heat won't get from its base to its tip fast enough. Using fluid is possible, but adds another system that can fail. If no…

please check my didactic example here: https://news.ycombinator.com/item?id=46862869

"Radiators can shadow each other," this is precisely why I chose a convex shape, that was not an accident, I chose a pyramid just because its obvious that the 4 triangular sides can be kept in the shade with respect to the sun, and their area can be made arbitrarily large by increasing the height of the pyramid for a constant base. A convex shape guarantees that no part of the surface can appear in the hemispherical view of any other part of the surface.

The only size limit is technological / economical.

In practice h = 3xL where L was the square base side length, suffices to keep the temperature below 300K.

If heat conduction can't be managed with thermosiphons / heat pipes / cooling loops on the satellite, why would it be possible on earth? Think of a small scale satellite with pyramidal sats roughly h = 3L, but L could be much smaller, do you actually see any issue with heat conduction? scaling up just means placing more of the small pyramidal sats.

Post reply on HN