111–120 of 230 posts
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- you seem to know what you are talking about - is there a place that you recommend where they teach you how rockets work, what is involved in building one, the math and physics behind it, materials required etc etc?
Kerbal Space Program
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The projections are questionable, but this is something the US and China are experimenting with as well. 1 and 2 are still open questions, but these are not aimed to be commercial grade DCs - this is basically edge compute (think a handful of racks). 3 is not a problem for defense usecases. (EDIT: Discussion here seems to point out that data OP is using might be flawed [1]). Ignoring the fact that just about every or…
This reminds me of the railgun. Basic math and physics tells us that not only would the (very expensive) barrels wear out very quickly, but that it would have had to be fitted on on a nuclear-powered pocket battlecruiser. Worse, the technology for firing any meaningful payloads from an electric gun (8" Small Diameter Bomb equivalents, guided, airburst, incendiary) simply does not exist. Same as with Musk's California…
A small but bright light in an economy where manufacturing jobs are hard to come by ( https://archive.ph/Haj8n ).
It’s a strange place. They’re building out expressways and railways at a breathtaking pace (something like an entire Switzerland’s worth of new track every year), are simultaneously building out multiple nuclear reactors, exports and manufacturing are shooting up, but the cities still look like shit.
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.
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Somewhat, but rocket engineering has some upward cost pressures that offset the savings from being in India: expertise is expensive even adjusting for the cost of labor (many staff are likely competing on salary with the rest of the world--rocket engineers/scientists are in high demand with lots of likely sponsors for immigration); aerospace materials/fabrication have a pretty global supply and patent chain even give…
My cousin is an aerospace engineer and works in ISRO (Indian space research organization), its impressive what they are doing but I'd like to chime in on a few things. I am unsure about private salaries but in govt. jobs, because it follows a rigid structure, the salary is still lower than what you might expect and is around the mark of 20-25 thousand dollars per year. It's similar to administrative services or depen…
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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.
The radiator is much more efficient than the solar panels (for obvious reasons), so that’s not the limiting factor. As to power, Caltech is already at 2-3 pounds per square meter: https://magazine.caltech.edu/post/sspp-space-solar-power-pro... > Another way to think about it: An SSPP spacecraft with a 60-meter-by-60-meter surface area made using today’s space PV-cell technology would cost $36 million and weigh nearly…
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OP is quoting Mikhail Klassen at Planet Labs [0]. The cost of replacement is exorbitant for commercial usecases, but is acceptable for defense usecases. The issue is too many people are looking at the commercial usecase while ignoring the defense usecase that is what is actually driving the conversation and dealflow in this segment. [0] - https://www.mikhailklassen.com/posts/orbital-data-centers/or...
Ok, there are at least two bad assumptions there. First, it assumes the radiator is at the same temperature as the GPU. But radiators become dramatically more effective as temperature increases, with radiated power increasing as the fourth power of absolute temperature. So a heat pump that drives the radiator at higher temperature could make the radiator far smaller. More power would be required (and the radiator wou…
> First, it assumes the radiator is at the same temperature as the GPU. But radiators become dramatically more effective as temperature increases, with radiated power increasing as the fourth power of absolute temperature. So a heat pump that drives the radiator at higher temperature could make the radiator far smaller.
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. So small radiator = big pump + extra solar panels and batteries + dead GPU
Also, how do you deal with the added cost and complexity for the solar tracking mechanisms for the "edge-on-to-the-Sun" radiator?
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This reminds me of the railgun. Basic math and physics tells us that not only would the (very expensive) barrels wear out very quickly, but that it would have had to be fitted on on a nuclear-powered pocket battlecruiser. Worse, the technology for firing any meaningful payloads from an electric gun (8" Small Diameter Bomb equivalents, guided, airburst, incendiary) simply does not exist. Same as with Musk's California…
As raynier and pfdietz pointed out [0], the assumptions you are using aren't necessarily correct. [0] - https://news.ycombinator.com/item?id=49039873
My response:
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. So small radiator = big pump + extra solar panels and batteries + dead GPU
Also, how do you deal with the added cost and complexity for the solar tracking mechanisms for the "edge-on-to-the-Sun" radiator?
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This reminds me of the railgun. Basic math and physics tells us that not only would the (very expensive) barrels wear out very quickly, but that it would have had to be fitted on on a nuclear-powered pocket battlecruiser. Worse, the technology for firing any meaningful payloads from an electric gun (8" Small Diameter Bomb equivalents, guided, airburst, incendiary) simply does not exist. Same as with Musk's California…
Soviets definitely experimented with airborne CO2 lasers.
A small but bright light in an economy where manufacturing jobs are hard to come by ( https://archive.ph/Haj8n ).
It’s a strange place. They’re building out expressways and railways at a breathtaking pace (something like an entire Switzerland’s worth of new track every year), are simultaneously building out multiple nuclear reactors, exports and manufacturing are shooting up, but the cities still look like shit.
- 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 - 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.
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Also, Pixxel, Skyroot, and Agnikul are targeting orbital data center launches this year for defense applications (which is what the entire ODC story is about). The US NRO already uses India's Pixxel [0] along with Finland's ICEYE (which is now co-manufacturing synthetic aperture sats in India with Agnikul [1]) for hyperspectral scanning. Edit: can't reply > But.. why? Missile Defense and C4ISR [2]. Seconds matter, so…
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…