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Comment by NitpickLawyer | Hacker News Reader

There's been a lot of talk about orbital DCs lately, but with these levels of density, orbital CDNs might be a more obvious usecase. It would be interesting to see if something like Starlink can use something like this to cache media content and reduce their overall data moving through the constellation. It could even be worth it to have some satellites in higher orbits (even GEO if the ground hw can reach it) dedicated to streaming media content. You can tolerate higher RTT for content that doesn't need to be real time.

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no, absolutely not. orbital datacenters are never going to happen, it doesn't matter whether you try to frame them as compute or storage or whatever else.

the extreme density of these SSDs is actually an anti-feature in the context of spacecraft hardware.

the RAD750 CPU [0] for example uses a 150nm process node. its successor the RAD5500 [1] is down to 45nm. that's an order of magnitude larger than chips currently made for terrestrial uses.

radiation-hardening involves a lot of things, but in general the more tightly packed the transistors are, the more susceptible the chip is to damage. sending these SSDs to space would be an absurd waste of money because of how quickly they would degrade.

and then there's the power consumption & heat dissipation. one of these drives draws 25W [2] and Dell is bragging about cramming 40 of them into one server. that's a full kilowatt of power - essentially a space heater in a 2U form factor.

0: https://en.wikipedia.org/wiki/RAD750

1: https://en.wikipedia.org/wiki/RAD5500

2: https://americas.kioxia.com/content/dam/kioxia/en-us/busines...

In the limit, packing transistors tighter should mean more radiation resistance, not less, because you can shield them with a smaller mass of water or lead or whatever.

It would be funny if lead-acid batteries end up being space-grade, should the lead be able to serve as a radiation shield.

IIRC, metals aren’t great shields because of secondary particles emitted after the first one hits the shield.

The water cooling system then serves multiple functions, including acting as a radiation shield.

> order of magnitude

It is much worse than that. Even taking the node names at face value[1] that is just one dimension, there are two/three[2] dimensions to consider so it would be 100x different.

Nehalem(2008) was a 45nm node based chip and had ~3MTr/mm2 transistors in comparison today we have 3nm(N3E/P/X/C) nodes(2023-4) from TSMC area about 220MTr/mm2.

Of course that is just one metric- transistor count, there are many other improvements to consider over the last two decades.

[1] Processor node names after all haven't been tied to physical scale for 30 years https://www.eejournal.com/article/no-more-nanometers

[2] HBM that modern GPUs use already leverage 3D ICs.

AFAICT[1] the latest generation of SpaceX Starlink satellites use AMD Versal XQR SoCs, which are built on a 7nm process with components like the main processor (dual-core ARM Cortex A-72) and memory (DDR4) clocked in the gigahertz, not megahertz, range.[2] At least some of these SoCs models (presumably the lower-clocked ones) are certified for geosynchronous orbits, not just low-earth orbits.

[1] https://www.pcmag.com/news/amd-chips-are-powering-newest-sta...

[2] https://docs.amd.com/r/en-US/ds955-xqr-versal-ai-edge/Genera...

Just to put in my 2 cents as someone tangential and sometimes a little too close for comfort for the field: with FPGAs (aka the half of this SoC doing the real work) there's often a lot of work that goes into radiation tolerance and hardening which are different things. It's not like you can just put the chip in space and be done. You have to do things like scrubbing the "bitstream" regularly for errors, triple-module-redundancy (aka cut yourself to 1/3rd of the chip's capacity), and other stuff.

What is the designed lifespan of a Starlink satellite?

5 years.

https://starlink.com/public-files/Starlink_Approach_to_Satel...

I don’t think the flash storage would keep data integrity for that long without a lot of redundancy. Also, processing capacity would be limited as well. Is there a problem that can be solved with a LEO server that can’t be better solved with the same amount of money sitting in a datacenter somewhere?

Pumping the SpaceX IPO.

$20 FPGAs have single event upset modules built in these days. You really think it's that hard to make a 2kB bootloader triple or quadruple redundant?

It's possible to run modern GPU on a sattellite: https://www.starcloud.com/starcloud-1

Some error rate is acceptable for uses which aren't "mission-critical".

Redundancy and error correction should be built into such huge arrays anyway. Its amount just needs to be increased.

The RAD750 is like 20 years old and is the absolute king in high reliability in the most extreme radiation environments. LEO is much more forgiving and there's plenty of examples of commercial gear operating in it. You could definitely put this much storage into LEO along with some EDAC and be fine for a few years.

For the sake of the generations that come after us, we really should not dump valuable material into space. I somehow doubt the electronics in space would be recovered and recycled properly.

Nothing is recycled properly. Recycling was a story told to ease consumers minds so they keep on consuming. The stuff you throw away ends up on a landfill, in the sea, or on a ship to someplace else where it gets burned and then buried. Sending it to space makes absolutely no difference.

Most steel and aluminum and nearly all copper is recycled

How do you know?

It would be relatively obvious from the difference between production and mining output.

So is there public data?

Places decent money for it

At some point a massive landfill will become more economically viable to mine for rare or useful elements than an actual mine. There is a good case for piling rubbish into to a well-managed landfill for future generations to mine with better technologies.

Also, burning plastic waste in a power plant at least liberates the energy for use. One can argue it's just fossil fuels that spent time doing something useful before it became energy.

Taking rare elements to space only for it to stay up there or burn up in the atmosphere removes it from this whole equation.

Might be true in the US, but its a lie in many other countries, a lie typically peddled by climate change deniers. Paper, cardboard, glass, metal, plastic bottles is certainly recycled to a high degree here (up to 99% for some of these categories), but plastics other than bottles are hard because there's so many types of it and its usually stuck to something else.

Around 9–14% of plastics are recycled worldwide, and almost none of electronics or other products that would have to be disassembled first.

I don’t know where "here" is for you, but even a country like Germany only manages to recycle 38% of plastics overall, and a huge portion of that is plastic bottles - the lowest-hanging fruits of the recycling tree.

And all the while, every day millions of single-use vapes are sold and discarded, each of which containing a microcomputer and rechargeable battery. Recycling is a lie.

Guess you just ignored the items I wrote.

I don't think I did; what you wrote just doesn't really address the problem. Yes, in a few industrial countries, raw materials that can be easily separated will be recycled. But that just isn't the real problem, when all the electronics and glued components and biological waste and mixed trash are impossible to recycle. People are told to just buy more stuff all the time, to a point where maintenance or repairs are economically unsustainable for many things. And I also don't understand how pointing out this travesty is somehow a climate change denier position.

I dont disagree, but your original statement was extremely broad.

Or you could use fibre, which has the advantage of not needing to use > 1kw of concentrated microwave to get ~2gig of throughput

Or even better not yeeting it into an environment where its cooked/cooled every 90 minutes

Or even better where its not absolutely pelted by cosmic rays enough to obliterate a good GB a day of data.

Or space data centre.

If I correctly understand what you're suggesting, then that could save on uplink bandwidth. Sending one copy into space, and then sending it back down over and over again sounds nice.

But does it solve a problem that we actually have? Is uplink bandwidth a pressing limitation?

What exactly is the selling point for an orbital data centre?

Satellites for connectivity to ground-based data centres seems to make sense, but that seems like it's relatively light hardware compared to a rack full of compute and storage.

If we're looking for apocalypse-scale redundancy, we already have all sorts of ground-based infrastructure and multi-continental designs on earth already.

I wonder if it's some weird play in the seasteading style-- if they put the data in space, it's outside the reach of any government except ones willing to jam the airwaves or fire missiles capable of reaching orbit.

/me turning in my sleep muttering https://en.wikipedia.org/wiki/Teledesic

why pollute the skies?

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