Comment by wcfields
5 days ago
Someone else with more experience could chime in but I would put it at less practical due to latency (sats are very high up), bandwidth (one laser vs a bundle of 1000s of fiber optic cables), cost (to overcome latency you need a closer orbit which requires more sats), single point of failure, lifespan, intercepted communications, solar flares… and that’s just off the top of my head.
I don't actually think latency would be that much worse.
Of course, it depends on the altitude of the satellite but speed of light in a fiber optic is only ~2/3rds of speed of light in a vacuum so you can afford some detour
> speed of light in a fiber optic is only ~2/3rds of speed of light in a vacuum
That made me wonder: Why can't we use vacuum cables?
(the sort of questions I should probably be bothering an LLM with.. someone should make a LMGPTTFY)
If you figure out how to make cheap vacuum cables you will probably become very rich.
But otherwise chains of microwave links does get much closer to c in applications where you want absolute lowest latency (or much more commonly, when digging a fiber line is too expensive)
> Why can't we use vacuum cables?
Hollow-core fiber is basically this!
> LMGPTTFY
"let me go prompt that for you" or "let me GPT that for you"?
1 reply →
Not vacuum but an inert gas: https://www.thefoa.org/tech/ref/fiber/Hollow-core-fiber.html
You probably can’t get under 500 km orbit, so 2000 km round trip is the shortest you can do between you and a ground based server. That’s 150 ms minimum round trip latency.
Light travels 2000 km in 7 ms. Maybe you took the inverse and got 150 Hz?
latency lower for satellites, trading firms have looked at this already, no idea if anyone has actually done it
bandwidth would indeed be worse
starlink sats are some of the lowest orbiting satellites in space - 330-370km for v3. this helps latency as well as easy deorbit at end of life. the v3 sats have multiple 400 gbps lasers for meshing... I can't decide if your comment is sarcasm or not actually because starlink is fully functional and doesn't have any of those issues
*Gbps
(Irritiating, but not as bad as those who insist on having milli-bit speeds I grant you).
Nice catch, gJim