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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

#131

Post by NelsonMinar »

lupusreal wrote: post #7

> "We actually serve over lasers all of our users on Starlink at a given time in like a two-hour window" I can't figure out what this sentence means.

I think it means pretty much all Starlink users have at least some data go over laser links every two hours. Which is a bit of surprise to me, if true. I have a year or so of fine-grained latency detail taken with IRTT on a Starlink connection, I should sit down and see if I can see times I'm using a satellite. Latency is highly variable in Starlink though so it's pretty noisy data.

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

#132

Post by malablaster »

stcredzero wrote: post #60
sephamorr wrote: post #57

Earlier quoted context omitted.

Take a look at the slides from the presentation, I think the geometry clearly shows cross-plane links in the mesh. Having worked on these types of systems, I've had more difficulty with the lookahead angles (rx from where the target was, tx to where it will be due to speed of light) than the tracking -- fine tracking performance was required for all modes, and it largely became a GNC and acquisition time issue (since…

GNC?

[flagged]

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

#133

Post by jstummbillig »

MeImCounting wrote: post #98
new_user_final wrote: post #87

Earlier quoted context omitted.

Bangladesh, the whole country, usage 2,300Gbps as of 2021. So 1 Petabyte per hour? Edit: It's international traffic. YouTube, Facebook video has local cache server by ISP.

This is a useful scale of comparison and what I think OP was after

OP agrees

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

#134

Post by HPsquared »

gnrlst wrote: post #103
latchkey wrote: post #88

I sit in my hot tub at night and see 1-2+ satellites go over every single time I'm out there. Which also makes me wonder how many of the shooting stars I've seen recently are just old starlinks burning up.

How do you spot a satellite? I've never seen one.

1. The satellite needs to be passing overhead at an angle where you can see it, and clear skies etc.

2. The sky needs to be dark enough to see it (so twilight or night)

3. The satellite needs to be illuminated by the sun.

4. The satellite needs to reflect enough light that you can see it.

Basically this happens just before sunrise, and just after sunset. So the ground and sky are dark (allowing you to see through the atmosphere), and the satellite - being at high altitude - is still illuminated.

As they pass overhead, you can often see them suddenly vanish as they pass into the Earth's shadow.

The International Space Station is a good one to find, as it's quite bright (very large).

There are various websites and apps; some phone apps use the GPS and magnetometer to show you what direction and time to look, and a search tool to look for visible objects at your location. It used to be really good with the old Iridium satellites, which gave a bright flash due to their large flat antennas.

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

#135

Post by dtgriscom »

vikingerik wrote: post #124
organsnyder wrote: post #86

Earlier quoted context omitted.

That's actually a somewhat useful visual.

Not really unless you're using 1 GB flash drives from fifteen years ago. 256 GB is now common, which would make that petabyte less than 1 football field. (It's only 4096 such drives.)

You can buy a 1TB microSD card for $150 now.

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

#136

Post by streb-lo »

latchkey wrote: post #110
gnrlst wrote: post #103

Earlier quoted context omitted.

How do you spot a satellite? I've never seen one.

To me, they look like little white dots moving across the sky. Brightness can change as they move too. It'll start off bright and then as it goes away it eventually disappears entirely. Since I usually sit in the same position in the hot tub, I've come to notice that I usually see one of them cross a pretty specific path from north to south, so I've gotten used to looking in that part of the sky as I'm sitting there.…

Just throwing this out there, but has anyone else seen 'formations' of satellites? I've only seen them once but there were about 5 to 10 (it was a while ago) of what I'm assuming are satellites moving in a line formation at high speeds across the night sky. They're too distant and too fast to be planes so I'm assuming they are some sort of military formation of satellites?

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

#137

Post by yencabulator »

polishdude20 wrote: post #34
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…

Phased array antennas probably have a lot to do with this. You can aim the signal more accurately and faster than any mechanical system ever could.

Surely the lasers aren't phased arrays.

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

#138

Post by unwiredben »

streb-lo wrote: post #136
latchkey wrote: post #110

Earlier quoted context omitted.

To me, they look like little white dots moving across the sky. Brightness can change as they move too. It'll start off bright and then as it goes away it eventually disappears entirely. Since I usually sit in the same position in the hot tub, I've come to notice that I usually see one of them cross a pretty specific path from north to south, so I've gotten used to looking in that part of the sky as I'm sitting there.…

Just throwing this out there, but has anyone else seen 'formations' of satellites? I've only seen them once but there were about 5 to 10 (it was a while ago) of what I'm assuming are satellites moving in a line formation at high speeds across the night sky. They're too distant and too fast to be planes so I'm assuming they are some sort of military formation of satellites?

That's often a recently launched StarLink formation -- the bunch up in a line when deployed, and have to be maneuvered over several weeks to spread out and take different orbits.

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

#139

Post by aetherspawn »

qayxc wrote: post #104
latchkey wrote: post #88

I sit in my hot tub at night and see 1-2+ satellites go over every single time I'm out there. Which also makes me wonder how many of the shooting stars I've seen recently are just old starlinks burning up.

> Which also makes me wonder how many of the shooting stars I've seen recently are just old starlinks burning up. Probably close to none. The lifetime of the satellites is about 5 years give or take. According to this page [1], a total of 355 satellites have deorbited over the past roughly 5 years. That's an average of about 71 per year or about one every 5 days. Since planned disposals are done over uninhabited area…

If someone makes a mistake and the satellite deorbits in the wrong place, am I likely to be impaled by a satellite screw or something travelling at terminal velocity?

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

#140

Post by pxeger1 »

gnrlst wrote: post #103
latchkey wrote: post #88

I sit in my hot tub at night and see 1-2+ satellites go over every single time I'm out there. Which also makes me wonder how many of the shooting stars I've seen recently are just old starlinks burning up.

How do you spot a satellite? I've never seen one.

My tip is that the very central part of your field of view has worse night vision than the rest (trading off for higher resolution instead), so if you spot something moving in your peripheral vision, don’t try to look straight at it or it’ll disappear; instead, look slightly to the side, and it’ll be easier to see (although maybe blurrier).
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