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Starlink's laser system is beaming 42 petabytes of data per day

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Re: Starlink's laser system is beaming 42 petabytes of data per day

#241

Post by caymanjim »

FpUser wrote: post #218
ortusdux wrote: post #11

Earlier quoted context omitted.

> “Another really fun fact is that we held a link all the way down to 122 kilometers while we were de-orbiting a satellite,” he said. “And we were able to downstream the video.” > For the future, SpaceX plans on expanding its laser system so that it can be ported and installed on third-party satellites. The company has also explored beaming the satellite lasers directly to terminals on the Earth’s surface to deliver…

So what happens to the laser beam when there are clouds?

The lasers aren't used for ground-to-satellite comms. While they refer to some of them maintaining a link through the atmosphere, the lasers are intended for satellite-to-satellite communication way above the atmosphere.

Re: Starlink's laser system is beaming 42 petabytes of data per day

#242

Post by [deleted] »

londons_explore wrote: post #228
nomel wrote: post #182

Earlier quoted context omitted.

In general , how is the initial alignment performed? Is there rough pointing, followed by some rastering, until the sensor gets a hit? Maybe with some slight beam widening first? My assumption is that you would want exactly one laser, one sensor module, and probably a fixed lens on each? Is the sensor something like a 2x2 array, or pie with three pieces, to allow alignment? Or is it one big sensor that uses perturb a…

A laser that transmits data at 100Gbps can also transmit at 1 bit per second with an additional path loss of 110 decibels. You'd normally achieve this by transmitting a well-known pseudorandom sequence. You also need clock stability into the ppb range. A path loss of 110 decibels is huge . It can easily account for your lenses being hugely off axis.

[deleted]

Re: Starlink's laser system is beaming 42 petabytes of data per day

#243

Post by [deleted] »

mrb wrote: post #225

So 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…

[deleted]

Re: Starlink's laser system is beaming 42 petabytes of data per day

#244

Post by garciasn »

mrb wrote: post #225

So 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…

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.

Re: Starlink's laser system is beaming 42 petabytes of data per day

#245

Post by londons_explore »

sneak wrote: post #234
londons_explore wrote: post #228

Earlier quoted context omitted.

A laser that transmits data at 100Gbps can also transmit at 1 bit per second with an additional path loss of 110 decibels. You'd normally achieve this by transmitting a well-known pseudorandom sequence. You also need clock stability into the ppb range. A path loss of 110 decibels is huge . It can easily account for your lenses being hugely off axis.

What books or webpages do I read to learn how to understand the why of your first sentence?

This is from the Shannon-Hartley theorem, the 'power limited case':

https://en.wikipedia.org/wiki/Shannon%E2%80%93Hartley_theore...

Re: Starlink's laser system is beaming 42 petabytes of data per day

#246

Post by tonetegeatinst »

mrb wrote: post #225

So 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…

Yeah 1TB seems average for anyone in IT who is really into data.

I'm kinda pissed their is no local ISP competition in my area....and iv tried reaching out to companies with little success...or they say were expanding to your area soon but will not say when.

10GB symmetric fiber isn't hard. Hell I'd use more bandwidth if I could but I'm stuck with no fiber atm

Re: Starlink's laser system is beaming 42 petabytes of data per day

#247

Post by supriyo-biswas »

bagful wrote: post #235
Havoc wrote: post #232

In the long run that could become a massive strategic advantage for the US. A 2nd layer of resilience over undersea cables

A privately-held strategic advantage?

Offloading the risk on private players, reduces the amount of government investment required, and shields them from any criticism, should the project fail.

Also, if it is that strategically important, the government can just buy SpaceX.

Re: Starlink's laser system is beaming 42 petabytes of data per day

#248

Post by roywiggins »

bagful wrote: post #235
Havoc wrote: post #232

In the long run that could become a massive strategic advantage for the US. A 2nd layer of resilience over undersea cables

A privately-held strategic advantage?

It doesn't really matter who owns it as long as it can be bent towards national goals when it matters.

American vehicle manufacturing was a strategic advantage during WWII because they swiftly pivoted to selling tanks to the government instead of cars to civilians.

Re: Starlink's laser system is beaming 42 petabytes of data per day

#249

Post by danbruc »

jstummbillig wrote: post #65

I have absolutely no idea how that number relates to any comparable operation. Can anyone add a banana for scale?

According to a quick search the average US household is closing in on 600 GB of traffic per month, that makes 42 PB per day the internet traffic of 2.1 million households. Incidentally the second picture in the article says 2.3M+ customers. With an US average of 2.5 people per household that is the traffic of 5 million people or 1.5 % of the US population.

Re: Starlink's laser system is beaming 42 petabytes of data per day

#250

Post by caymanjim »

Thaxll wrote: post #219
zetsurin wrote: post #215

Earlier quoted context omitted.

Based on 2160p movies i've seen around the very largest max out at around 100, and 40 is more common, so this seems wrong.

We're not talking pirated movie here, think Netflix and Youtube.

Netflix and Youtube streams are less GB/hour than a typical movie rip. Roughly 3GB/hour at 720p and 8GB/hour at 4K. A decent-quality pirated 4K movie is more like 20GB/hour. A high-quality rip is 40GB/hour.
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