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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

#21

Post by Scoundreller »

sandworm101 wrote: post #8
ble wrote: post #5

My 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.

Indeed Iridium had to deal with the same thing (or I guess, didn’t):

“ Cross-seam inter-satellite link hand-offs would have to happen very rapidly and cope with large Doppler shifts; therefore, Iridium supports inter-satellite links only between satellites orbiting in the same direction.”

https://en.m.wikipedia.org/wiki/Iridium_satellite_constellat...

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

#24

Post by jlmorton »

1oooqooq wrote: post #15

[flagged]

Is this a serious question? You think SpaceX developed the industry-leading orbital rocket, launched hundreds of times to deliver thousands of in-house developed satellites utilizing homegrown, novel argon gas ion thrusters, to develop a global satellite internet system using inter-satellite laser links, their own in-house developed, incredibly inexpensive phased array antenna system, and everything else, and they forgot to use TLS?

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

#26

Post by Scoundreller »

Symmetry wrote: post #20
ble wrote: post #5

My 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…

Right. The Iridium network had communication between satellites in different orbital planes passing each other but that was a pretty unusual capability.

I wonder how iridium actually handles the tracking (or if it’s just slow enough and lack of attenuation in free space just lets them blast it).

And if they have zones where they don’t go to adjacent orbits, but instead go up or down within their orbit for the handover between orbits.

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

#27

Post by diggan »

mschuster91 wrote: post #6

> The lasers, which can sustain a 100Gbps connection per link > Brashears also said Starlink’s laser system was able to connect two satellites over 5,400 kilometers (3,355 miles) apart. The link was so long “it cut down through the atmosphere, all the way down to 30 kilometers above the surface of the Earth,” he said, before the connection broke. How do these tiny satellites achieve this kind of accuracy and link qua…

> (Meanwhile, me on Earth, has link quality issues due to a speck of dust on a fiber connector)

It's incredible really. I remember when I was a kid living with my mom on an island, we got broadband relatively late (compared to the rest of the country), as the island required antennas for getting mainland and the island linked, instead of cables. I think it was set up that way because of costs or something, remember it being expensive...

Regardless, the antennas were setup and we finally got broadband, but every time it got a bit windy and/or rainy, the links started to have huge issues, especially if the lake got lots of waves, then the connection simply disappeared.

And now it seems almost like magic to me how the same setup is literally done but way above our heads, in a really hostile environment like space.

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

#28

Post by phh »

aPoCoMiLogin wrote: post #16
1oooqooq wrote: post #15

[flagged]

so you are asking if the traffic is additionally encrypted? i don't think that additional encryption is needed, like your ISP doesn't additionally encrypt your TLS encrypted traffic, that would be waste of resources

Except wifi is encrypted

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

#29

Post by hn8305823 »

aPoCoMiLogin wrote: post #16
1oooqooq wrote: post #15

[flagged]

so you are asking if the traffic is additionally encrypted? i don't think that additional encryption is needed, like your ISP doesn't additionally encrypt your TLS encrypted traffic, that would be waste of resources

Metadata (src/dest ip/port) can be of high value, especially for cross-border traffic.

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

#30

Post by jlmorton »

7e wrote: post #14

Global internet traffic is estimated to be 3 yottabytes per day. So Starlink is now carrying one of out every 77 million parts of worldwide traffic. Wow, that's small. EDIT: there's some confusion information out there. With a more conservative estimate of 150.7 exabytes per month, Starlink gets 1 part of 119, which is more impressive.

Where do you get 3 yottabytes? That is difficult to believe. I see 150 exabytes per month [1], about a thousand times less.

https://gitnux.org/internet-traffic-statistics/ [1]

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