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This borders on science fiction. 88,000-and 1-million satellite clusters (as claimed in your link) are hard to take seriously, especially with the possibility of Kessler Syndrome. Also:

1. How do you cool your chips? Vacuum is a thermal insulator, so radiators are required to remove heat. nVidia (or even ASICs) require much and specialised cooling.

2. How does one radiation harden a H100?

3. I'm also seeing where TCO for these are 78x their terrestrial equivalents [0]. Is that financial sustainable?

And there still remain issues with power supply, regulations, and bandwidth. This feels more like a thought experiment rather than an actual serious engineering or business case.

[0] https://www.abiresearch.com/blog/data-centers-in-space

Mein Gott, you're not just making this up ( https://www.datacenterdynamics.com/en/news/neevcloud-and-agn... ).

But.. why?

Musk bandwagon-hopping? Investor bamboozlery? (Same diff?)

Is my borderline childish understanding of basic physics THAT off because I cannot see the value or utility (beyond a small smear of niche edge cases) of space-based compute?

- ed, disclosure: You seem to have edited your response whilst I was typing mine, adding in valuable links. Thanks!

> targeting orbital data center launches

I am regularly assured by HN denizens that orbiting data centers will never work.

It’s interesting that this is less funding/valuation than hundreds of other random B2B Series C/D companies that may not even exist in 5 years.

No point, just perspective.

Probably meant the third country with a private sector capability to launch rockets, US and China being the other two.

Liquid fueled launch vehicles aren't storable/able to be made ready at a moment's notice, unlike solids. Liquid fueled historical artifact:

https://en.wikipedia.org/wiki/SM-65_Atlas

There's a reason all modern silo based (and submarine) ICBMs are solids.

So has SpaceX. It's becoming standard practice these days.

What you see in Indian cities is a result of multiple factors (like everything):

- Low GDP per-capita, offset by immense scale, which means the central government can mobilize massive resources for national projects, but municipal bodies are financially starved (municipal revenues in India are < 1% of total tax collections, for context it's 6% in South Africa and 10% in Brazil). Cities are completely dependent on the state for money, unlike countries where cities control their own property and commercial taxes, so they raise very little on their own, and states have multiple other priorities so cities never get as much money as they need.

- Leading off the previous point - executive power over cities is very fragmented, most authority rests with state chief ministers and state-appointed bureaucrats rather than empowered local mayors, so city planning is subordinate to state-level political priorities. City management itself is divided among uncoordinated state-level bodies (separate agencies for roads, water, power, and transit). There's a lot of accountability voids where something goes wrong and everybody thinks it's a different body's responsibility. The poor coordination also means you'll have things like a road laid on Monday, and on Wednesday the water authority digs it up to fix pipes underneath.

- The Indian constitution guarantees freedom to move and reside anywhere, so it's not legally possible to control rural to urban migration like China did with its Hukou system. E.g. Bangalore adds anywhere from 350k to 600k people a year almost entirely from internal migration. Much faster than housing, transit, and civic utilities can keep up with.

Things are getting better, although slowly and unevenly:

- Mass transit is expanding rapidly

- Door-to-door solid waste collection now reaches roughly 98% of urban wards (tougher than you would think because the unrestricted migration tends to create a lot of ad-hoc unplanned settlements on the outer parts of cities)

- The central government is working on allowing cities to issue municipal bonds to raise their own funds.

- Bangalore now (as of last year) has a single body called the Greater Bangalore Authority that has statutory oversight over previously uncoordinated agencies that handle water, transport, power, transit etc. Other state governments with major cities are watching to see how it plays out, and will likely copy + adapt it to their own major cities based on how it goes.

India thrives in high tech sectors that are ironically export controlled by the rest of the world. That’s the primary reason the talent in those domains stays back.

As for the rest of India, you can largely find the root causes of problems by tracing adverse selection effects among the elites that do remain, massive, conflicting vested interests and decades of horrible, incompetent policymaking.

Don't you need at least a little thrust ~40 mins later to circularize the orbit?

Obviously solid rockets can't be relit.

Could that be the use of the 4th stage?

Solid motors are simpler, but I wouldn't say they're more reliable. It was the solid booster failure that caused the Challenger disaster, and solid booster failures that have caused ULA's Vulcan Centaur rocket to be grounded. As you say, solids can't be throttled or turned off easily. They also can't be test fired. Yes, you can static fire a solid rocket and reuse the housing/nozzle/etc, but solids often fail due to imperfections in the propellant. Pockets of air or fractures in the propellant can cause a sudden increase in propellant surface area, which then generates more pressure, potentially blowing up the booster. With a liquid rocket, the engine can shut down if there's an anomaly. But with a solid, there's no option but to let the reaction continue.

There's also the issue that a solid booster must be "fueled" before it reaches the pad, meaning you have ground crew working around a large quantity of explosive material. A Brazilian solid rocket exploded on the launch pad, killing 21 people.[1] Liquid rockets can be made inert until everyone is far away, then loaded with propellant.

A big advantage of solid rockets is that they can be stored for long periods and quickly launched. This is handy for use cases like ICBMs, but not particularly important for commercial launches.

1. https://en.wikipedia.org/wiki/VLS-1_V03

The person has nothing to add to the conversation, that's why he's bringing politics to it (which obviously he has no control over)

The answer is positive. LEO satellites need orbital corrections every few weeks, and some, several times a week.

It is critical to avoid a boondoggle gap.

If I understand correctly, NY is concerned about the power and water consumption. 1. How do they get power in space? (solar) Do the same on earth at 1/100 the cost (or build 50x the number of solar to account for atmospheric loss and you will still come out ahead) 2. How do they get water in space (they don't). Whatever they do in space to not need water, do the same on earth! 3. People don't like living near datacenters - put them in remote areas hundreds of miles away from people, after all space datacenters won't have employees . Again, at 1/100 or 1/1000 the cost.

If the "physics" tells you that your satellite cannot radiate heat away from your nVidia GPU cluster because each H100 needs 1.1 meter square of radiator, then opinions do not matter. The same applies to power supply and bandwidth.

What I repeatedly read here was it is physically not possible to build an ODC because of heat problems and alpha particle problems.

Maybe you need to let them know.

They were founded in NZ by a NZer, they launch from NZ, their employees are NZers. Calling them a US company is equivalent to saying Google is Irish.

I can’t imagine how inefficient a country would be if they tamped down all their magical thinking. FFCS, SMILE, and EUVL are all magical thinking if you ask me. Some of the craziest things humans have ever conceived of.

The Caltech Concept is just that — a concept. No prototype, no tests, no manufacturing, no results. When they achieve this order of magnitude improvement on a prototype scale, that's when we should take them seriously.

I have a lot of respect for Atwater but I'm pretty sure a lot of people at Caltech think this is donor driven research.

> Carnot's theorem and refridgeration cycles rear their head. Your heat pump still needs power to pump heat uphill., negating any savings from a smaller radiator. And what happens when you shrink a radiator? It becomes a high temperature radiator, meaning the GPU must operate outside its operational tmperature of about 70 degrees C.

Sorry, that's all nonsense. Yes, the extra power needs to be radiated. But the advantage of operating at high temperature is so extreme that the more effective radiation will overwhelm that unless the heat pump is extraordinarily inefficient. If the heat pump would be perfect, operating at the Carnot limit, then if it doubled the absolute radiator temperature it would double the amount of energy to be radiated, but the area of the radiator would decrease by a factor of (2^4)/(2) = 8.

As for the second point, no, this does not require the GPU to operate at higher temperature. What made you conclude it would?

> Also, how do you deal with the added cost and complexity for the solar tracking mechanisms for the "edge-on-to-the-Sun" radiator?

I don't need to; I'm just debunking a bad argument. What you are doing there is called "moving the goalposts". But satellites normally have means of orienting PV toward the Sun. So, maybe have the radiator perpendicular to those? Those claiming the idea violates the laws of physics and using solar absoption on the radiator as part of the argument need to show no such scheme can work, even in principle.