>>alden5+(OP)
[dupe] >>39199368

>>sandwo+z65
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...

>>7e+m85
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]

>>biling+Zk5
Internet says no: https://www.cnbc.com/2021/11/19/german-space-lasers-company-...

>>jstumm+ht5
> If you took a petabyte's worth of 1GB flash drives and lined them up end to end, they would stretch over 92 football fields.

https://info.cobaltiron.com/blog/petabyte-how-much-informati...

>>mschus+Z55
3M just invented a new fiber interconnect thing to mitigate the dust issue: https://www.3m.com/3M/en_US/data-center-us/applications/inte...

Maybe the future of usb in 10 years :)

>>jlmort+qf5
https://www.statista.com/statistics/216335/data-usage-per-mo...

>>latchk+Vx5
> 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 areas (e.g. the pacific ocean), the likelihood of spotting one is very low.

Hope that helps answer your question, even it wasn't necessarily meant seriously :)

    [1] https://starlinkinsider.com/starlink-launch-statistics/

>>moffka+sz5
In the context of the full article (https://en.wikipedia.org/wiki/Iridium_satellite_constellatio...), it's clear they're talking about the polar orbits used by the Iridium constellation, which have "seams" around the Atlantic and the Pacific as the "first" set of satellites passing north-to-south overlap with the "last" set of satellites coming back south-to-north on the other side of their orbits. So of the 6 orbital planes used by the Iridium satellites, each plane covers 1/12th of the globe for each "half" of its over-the-poles orbit. So there are two "seams" where handoff is not supported, one off the eastern seaboard and one roughly over Japan.

There's an animation on linked article that explains this pretty well: https://upload.wikimedia.org/wikipedia/commons/thumb/9/90/Ir...

>>gnrlst+2B5
The Starlink ones look like Santa's sleigh https://i.imgur.com/4S0vbfY.gif

>>Alifat+Ff5
>>39199368

>>gnrlst+2B5
https://james.darpinian.com/satellites/ Put in your location and it will tell you when and where to look at the sky to see one. Works great for me and hopefully it will work for you.

>>aether+1H5
China is still working on those reusable rockets...

https://www.youtube.com/watch?v=sDufpRp57ok

>>TheAlc+MB5
I live 10 miles from Boston and I've seen them a whole bunch. I've used https://james.darpinian.com/satellites/?special=starlink

>>streb-+tG5
> They're too distant

I don’t know how you would know that. People are very bad at seeing distances at these scales.

If they were indeed satelites they could be starlink satelites. They are put into orbit as a bunch together and then they spread along their orbital path as they take up their position.

This article has a picture, maybe you can check if it is similar to what you have seen? https://earthsky.org/space/spacex-starlink-satellites-explai...

If you could recall more details then maybe we can figure out more exactly what this might have been. (Such as where you were, which direction you were looking at, when did this happen, how fast did they cross the sky and how far the dots were from each other. Were the line spread in the direction they were moving or sideways?)

>>Scound+Zd5
Supposedly they use steering, since the horizontal azimuth to adjacent-plane satellites varies from 0 to 65 degrees across an orbit: https://apps.dtic.mil/sti/tr/pdf/ADA348174.pdf

>>why_at+HI5
It's absolutely incredibly small, think of how large the surface area of a sphere of LEO and the surface area of these lasers linking the vertices of the 5,289 satellites. The gaps between them are probably hundreds of kilometres. I would imagine that each link has multiple routes so if there was a failure traffic can still be routed in the same way the Internet has many routes.

https://satellitemap.space is pretty amazing but a Starlink satellite looks massive on there, really at the scales we are talking they wouldn't even be a pixel. Do we know how many of the satellites are actually interlinked by lasers?

>>nomel+MQ5
There's an interesting paper on the subject of alignment here. https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=4...

>>steve_+zQ5
Between when the sun first disappears below the horizon and when (nearly) all its light disappears, i.e., the end of astronomical twilight when the Sun's center is 18 deg below the horizon, seems to be about 90 minutes.

https://www.timeanddate.com/astronomy/different-types-twilig...

It's been awhile, but I'm pretty sure I've seen these much later than that. I'm talking about lying in a sleeping bag, looking up at the amazing starfields of pitch-black wilderness nights (tip: never use a tent except in extremis - look what you're missing!).

>>sneak+w56
This is from the Shannon-Hartley theorem, the 'power limited case':

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

>>roywig+U66
It's already been bent towards missile defense https://wikipedia.org/wiki/Starlink#Military_capabilities

>>garcia+y66
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/

>>supriy+M66
They probably wouldn't have to buy them, if there's a war on they probably have enough legal tools to just require SpaceX to sell them whatever capabilities they have.

https://en.wikipedia.org/wiki/Defense_Production_Act_of_1950

>>kuchen+A76
https://www.statista.com/statistics/420791/daily-video-conte...

300+ minutes a day for TV + vMOD (streaming services). Since no one actually watches TV anymore, at least not through traditional TV, I summed them.

>>calvin+k86
> Is resolution going to peak?

not for awhile. apple vision / oculus will stream (4k/8k) 3d movies.

https://developer.apple.com/streaming/examples/

>>topspi+gO5
I understand what you're saying... But lets check.

Assuming the lenses are about 2 inches across (from photos) and they are 1310nm IR lasers:

https://www.wolframalpha.com/input?i=single+slit+diffraction...

So we have a minimum beam width of 0.0014 degrees.

And the speed of light round trip distance is say 3.3 milliseconds.

So the question is, does the angle between the satellites change faster than 0.0014/0.0033 = 0.42 degrees/second?

Well the worst case is one satellite heading north at 7.4 Km/s and another heading south at 7.4 km/s. Lets assume the satellites are 550 km apart (the distance between planes at the equator), and use the small angle approximation... Comes out as 1.4 degrees per second.

So yes, these satellites do need the ability to aim transmit and receive in different directions! (although they might be able to just defocus the beam a little when angles are changing fast to trade off throughput for design complexity)

>>Scound+tV5
This has more details: https://fcc.report/IBFS/SAT-MOD-20131227-00148/1031348.pdf

Apparently it only happens above/below 68 degrees latitude, so the next satellite with a working inter-orbital-plane connection is at most one hop ahead or behind.

https://spaceflight101.com/spacecraft/iridium-next/ has some more photos and diagrams; seems like they're really mechanically steered even on the NEXT constellation.

>>seemaz+lf6
According to historical Nielsen data[1] from 1991 to 2009: most Americans.

Even back to 1950, for per household data, it was above 4 hours.

[1] https://www.nielsen.com/insights/2009/average-tv-viewing-for...

>>lannis+9a6
Note that, historically, the US Navy had plenty of its own shipyards, and did produce many of its own ships.

https://en.wikipedia.org/wiki/Category:United_States_Navy_sh...

But that's mostly been "optimized away" in more-recent times, in the name of Capitalism and Campaign Donations.

>>wkat42+l06
Some satellites do appear to flash because they are tumbling: https://www.satobs.org/tumble/tumbleintro.html

The flashing of satellites will generally be gentler than the short burst strobing of an aircraft.

>>alden5+(OP)
Just for context, here's SDA's Open Standard on how they expect to do connections over Optical Links. I assume the starlink terminals work in a similar manner:

https://www.sda.mil/wp-content/uploads/2023/06/SDA_OCT_Stand...

>>mlindn+3z6
> Actually the person you replied to somewhat incorrectly. They're not targeted re-entries because the on-board propulsion of Starlink is too low to precisely control the re-entry location.

SpaceX says otherwise, see [1]

   SpaceX spokesman James Gleeson, when asked about the 10 satellites, said SpaceX is “performing a controlled de-orbit of several first iteration Starlink satellites,” using onboard propulsion.  

There's a difference between unscheduled deorbiting (as happened to about 40 satellites after a solar storm in February 2022) and a scheduled deorbiting manoeuvre trigged by ground control. Starlink satellites use electric on-board propulsion (Krypton powered Hall thrusters) that doesn't run out as quickly as chemical or cold gas gas thrusters. There's also not much precision needed to avoid major population centres - Earth is pretty big after all.

[1] https://spacenews.com/spacex-launches-fourth-batch-of-starli...

>>Brybry+pF6
2022 data from the BLS: https://www.bls.gov/news.release/atus.t11A.htm

Men spent 3 hours a day watching TV, and women 2.5 hours. But TV time is lower (around 2 hrs/day) from ages 20-44, then increases again after 45 and peaks at 75 years old at nearly 5 hours a day.

Households without kids watch more TV, which surprised me.

>>solard+2W8
That's a nice find. I think BLS leisure time data is from the American Time Use Survey [1] which I think is asking something similar to this questionnaire [2] on page 22.

I'm not sure that's saying household time. For example, when they survey a household it wasn't clear to me if they survey everyone in the household or just one person. If it's one person then it sounds like they collect how that one person (age 15+) spent their own time and if there were kids in their household.

So then it'd be accurate to say that individuals in households without kids watch more TV as a singular activity (the survey doesn't allow simultaneous activities).

In comparison Nielsen used TV viewing diaries and automated data collection meters. You could have the TV on in the background while doing chores and it would still count.

It's interesting that the 2009 ATUS survey [3] had a 2.82 hour/person average because that's fairly different from the Nielsen data (4 hours 49 minutes/person).

I wonder if this difference is people underreporting in ATUS or Nielsen overreporting or a factor of differences in limitations in ATUS (no simultaneous activities allowed, 15+ age limitation) or Nielsen.

[1] https://www.bls.gov/opub/hom/atus/data.htm

[2] https://www.bls.gov/tus/questionnaires/tuquestionnaire.pdf

[3] https://www.bls.gov/news.release/archives/atus_06222010.pdf

>>schiff+096
Partially! There are also ascending and descending satellites meeting. Ascending and descending doesn't mean altitude but in a "2D view" sense. See https://www.heavens-above.com/StarLink.aspx

>>qayxc+P4a
Here's a blog post by ESA that talks about what controlled reentry means. https://blogs.esa.int/cleanspace/2018/11/16/basics-about-con... Controlled requires precise aiming towards a targeted location. Not just the operator deciding to do something. By ESA's definition Starlink de-orbits aren't even "semi-controlled".

This generally involves landing at a precise location of the Earth. It goes by a nickname, Point Nemo. A patch of ocean in the south pacific farthest away from any land. It's also far from standard shipping lanes. If you can't achieve this type of targeting it, definitionally, is not a controlled re-entry.

> It simply means aiming for a certain latitude by adjusting the orbit accordingly

You cannot aim a satellite for a "certain latitude" as orbits cannot follow lines of latitude. That's not how orbital dynamics work. I'm not quite sure what you meant to convey here.

> This also means that the target is not "all over the world" as you put it - it's a very narrow, well defined stripe/trace (remember the scale we're talking about here!) and that's exactly what a controlled de-orbit is about.

No it's all over the world, definitionally, because low earth orbits cross the entire planet as the Earth rotates. The possible locations the satellite can re-enter span a large portion of the globe from the negative to the positive latitude equivalent to the spacecraft's inclination.

I think you have a major misunderstanding yourself. If there's some term I'm using that you don't understand please let me know so I can help you.

>>mschus+Z55
This says more about the link budget than anything else, it's much harder to keep tracking when satellites are close to each other moving at high relative velocities. At the distances in your example, movement of the laser link optical head is very slow, on the order of 0.01 - 0.1 deg/s. Optical heads also have a control loop which actively corrects for pointing errors once a positive link is established. Check out: https://www.sda.mil/wp-content/uploads/2022/04/SDA-OCT-Stand...

>>Gravit+Zaa
Thanks, this is an important point. I missed the fact that Starlink's orbital planes actually cover the full 360° of RAAN[0], not just 180° like Iridium did (presumably to minimize the number of satellites).

So actually this Iridium-type "seam" disappears, meaning that every satellite should always have co-orbiting "neighbors" on both sides. Cool!

[0] https://en.wikipedia.org/wiki/Right_ascension_of_the_ascendi...