Re: [Starlink] Starlink "beam spread"

[Mike Puchol <mike@starlink.sx>]

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The primary reason for -not- offering service in any given country is, primarily, regulatory (see the South Africa case). Once they
> I'm not going to reason from "intersatellite" routing being operational until they offer it in operation. It's feasible, sort of. Laser beam aiming is quite different from phased array beam steering, and though they may have tested it between two satellites, that makes it a "link technology" not a network. (you can steer a laser beam by moving lightweight mirrors, I know. But tracking isn't so easy when both satellites are moving relative to each other - it seems like way beyond the technology base that Starlink has put in its satellites so far. But who knows.

We operate several of these in Kenya: https://x.company/projects/taara

They offer 20 Gbps at distances of 20km, and they operate under considerably more vibration, motion, and scintillation than you have in space. They have no issue keeping track of each other once initial acquisition is made. SpaceX launched 10 satellites into polar orbit in Jan 2021, which it used to test and characterize the ISL optical heads - you could see them positioning the satellites in configurations to test side-looking (thus cross-plane), and at different altitudes (cross-shell), and even parallel links to characterize hardware differences (we did this with ours in Kenya too). It was fascinating to watch. I’m quite certain the least problem for Starlink (unless they made major boo-boos in hardware or software) is acquisition and tracking.

A very good book (but not cheap) on the topic is "Free Space Optical Communication” by Hemani Kaushal.
> As far as "intersatellite" routing being out there soon, well, there's no evidence it's happening soon.

There is circumstantial evidence from a user in Nigeria that was getting service and exiting via London, there is no evidence that any of the gateways in Nigeria are operational, so ISL could have played a role: https://www.reddit.com/r/Starlink/comments/wwg0nc/starlink_speed_test_in_nigeria/

Best,

Mike
On Aug 31, 2022, 23:33 +0200, David Lang via Starlink <starlink@lists.bufferbloat.net>, wrote:
> On Wed, 31 Aug 2022, David P. Reed wrote:
>
> > What's interesting to me is that their coverage map definitely doesn't cover
> > Africa, South America, Cuba, large parts of Asia, and it isn't planned - if
> > they had "mesh routing" working among satellites, those would be easy. But
> > instead, they seem to be focused on the satellite one-bounce architecture
> > (what the satellite industry calls "bent-pipe" however it is done).
>
> The countries covered in the coverage map seems to be as much or more restricted
> by regulations as anything technical.
>
> David Lang
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