Wait, I thought only Kuiper has laser.
Starlink's laser system is beaming 42 petabytes of data per day
311–320 of 469 posts
Re: Starlink's laser system is beaming 42 petabytes of data per day
#312My understanding of the state of the art of inter-satellite optical links is that they have only been used between satellites that are basically in the same orbital plane and in more or less the same orbit. That is, the angle from one satellite to the other changes very very slowly, so that the optics don't have to do much tracking -- and consequently satellites can only form an optical link with other satellites tha…
Tracking is an issue, but doppler can also be a thing. At orbital speed (actually up to 2x orbital speeds) the doppler effect between two satellites can change the frequency enough to cause interference. Moving a scope to track a moving target is one problem, allowing the algorithms to adapt at the frequency shifts on the fly another.
Doppler is not a big problem with lasers because the carrier frequency is so much higher than RF that it doesn't matter; it's bang-bang AM modulated.
I'm assuming two things: That something like Manchester coding is being used so that some clock skew is tolerable, and that the laser carrier is not in fact being frequency or phase modulated. Last I checked FM and PM of optical frequencies was not yet practical outside of laboratories, but I'm happy to be corrected.
Re: Starlink's laser system is beaming 42 petabytes of data per day
#313Earlier quoted context omitted.
I think the average Instagram or TikTok user must be using more than 100GB/month. And if you count YouTube and Netflix, it's probably more than that.
Is resolution going to peak? Like speeding on a highway are there diminishing returns? On the other hand, bandwidth availability seems to also drive demand...
Two things:
Resolution is always determined by angular resolution at viewing distance, even for analog TVs(they were smaller and further away), and also,
Videos on Internet is always heavily compressed - the "resolution" is just the output size passed to the decoder and inverse of minimal pattern size recorded within, technically not related to data size. Raw video is h * v * bpp and have always been like low to dozen Gbps.
Just my bets, the bandiwth may peak or see a plateau, but resolution could continue to grow as needed for e.g. digital signage video walls that wraps around buildings.
Re: Starlink's laser system is beaming 42 petabytes of data per day
#314So that is "432 Mbit/s per laser, and 9000 lasers total". I don't know you guys but I find that statement much more relatable than "42 PB/day". Interestingly, they also say each laser "can sustain a 100Gbps connection per link" (although another part of the article even claims 200 Gbit/s). That means each laser is grossly underused on average, at 0.432% of its maximum capacity. Which makes sense since 100 Gbit/s is p…
The first slide says "9000+", suggesting that the number of space lasers is slightly over 9000. I feel like that's an important distinction.
Re: Starlink's laser system is beaming 42 petabytes of data per day
#315Re: Starlink's laser system is beaming 42 petabytes of data per day
#316Isn’t the user experience with starlink pretty abysmal for the average user? Both the service and the customer service?
It's pretty average ish.
You can try it out for 30 days and form your own opinion.
Re: Starlink's laser system is beaming 42 petabytes of data per day
#317Earlier quoted context omitted.
Netflix uses 3-7GB an hour. The average person is spending 4-5hrs a day watching TV. I’d say most are above 100GB/month. But that’s me.
Yep, but that data originates from the providers network and never leave the providers network, so they probably don't count it towards your usage the same way. I don't think that breaks net neutrality either, which the FCC seems to be reimplementing Edit: see https://openconnect.netflix.com/en/
This obviously has no relevance for starlink which does not have local datacenters for cdn purposes. All that bandwidth is going through the satellites right before it reaches the user.
Re: Starlink's laser system is beaming 42 petabytes of data per day
#318So that is "432 Mbit/s per laser, and 9000 lasers total". I don't know you guys but I find that statement much more relatable than "42 PB/day". Interestingly, they also say each laser "can sustain a 100Gbps connection per link" (although another part of the article even claims 200 Gbit/s). That means each laser is grossly underused on average, at 0.432% of its maximum capacity. Which makes sense since 100 Gbit/s is p…
There is one key issue of keeping lasers aligned for long durations between satellites and even between a satellite to a ground station. There are vibrations in satellites and even a tiny bit of that vibration translates to beam misalignment. Am not an expert though. That could explain the bursts.
So it's hard to sustain the theoretical 100GPS connection for hours let alone days across 2 end points which are in constant motion.
Re: Starlink's laser system is beaming 42 petabytes of data per day
#319Earlier quoted context omitted.
A privately-held strategic advantage?
Like all other US defense companies, why not? Do you think US Navy produces their own ships?
The distinction here is that ships are built by nongovernmental private enterprises, whilst Starlink is operated by a nongovernmental private enterprise. With a somewhat volatile executive.
Which isn't unprecedented. But it's also far from the equivalence your comment suggests.
Re: Starlink's laser system is beaming 42 petabytes of data per day
#320So that is "432 Mbit/s per laser, and 9000 lasers total". I don't know you guys but I find that statement much more relatable than "42 PB/day". Interestingly, they also say each laser "can sustain a 100Gbps connection per link" (although another part of the article even claims 200 Gbit/s). That means each laser is grossly underused on average, at 0.432% of its maximum capacity. Which makes sense since 100 Gbit/s is p…
I’d have guessed they count “delivered bytes” not “transmitted bytes” and then you need to take into account each leg of the transfer. Which for starlink is at least two (for the simple bend pipe situation) and up to potentially something like ?20? (for a “halfway around the globe, totally starlink” connection). The latter is probably statistically negligible, but even the factor two would give ~2% utility. Which, taking into account, that at least 2/3 of the orbit time is spend out of reach of anywhere useful, this would give something like 1 in 10 possible bytes being transmitted. Which is much better than I’d have guessed if asked blindly