[Starlink] Starlink Roaming

[Sebastian Moeller]

> On Feb 22, 2022, at 10:40, Mike Puchol <mike at starlink.sx> wrote:
> 
> The optical links work in IR spectrum, so non-visible. They would not be a concern for aircraft the same way green lasers are.

	Puzzled. IR lasers still wreck havoc when hitting the eye/retina, so why are these considered safer than visible spectrum lasers? In a lab context IR lasers are typically considered more dangerous as they are invisible and hence harder to see/avoid. I am happy to believe that there is a reason why they are safer, just trying ot reconcile that with my laser-safety seminar ;)


> On David’s comment "but if you can easily route traffic to a ground station that's further away and not currently saturated”, that is true as long as the path that is connected over ISL has visibility of that other ground station. I will add ISL to my tracker shortly so we can start simulating these things.
> 
> Best,
> 
> Mike
> On Feb 22, 2022, 12:04 +0300, Sebastian Moeller <moeller0 at gmx.de>, wrote:
>> Intersting!
>> 
>> Silly question, giving that there are already law suits for people pointing lasers at airplanes, how are these commercial laster terminals avoiding that issue?
>> 
>> Regards
>> Sebastian
>> 
>> 
>> 
>> 
>>> On Feb 22, 2022, at 08:42, Mike Puchol <mike at starlink.sx> wrote:
>>> 
>>> I did over-simplify so the point was better understood. On the optical gateways, these exist already: https://mynaric.com/products/ground-capabilities/
>>> 
>>> Once you have an optical mesh in orbit, the only practical way to provide it with massive capacity is optical links - there isn’t enough radio spectrum that would do it (without a massive ground gateway network with enough physical separation). You can create a network of optical gateways that guarantees a number of them will not be impared by cloud cover at any given time. Optical has the advantage of being license-free, too.
>>> 
>>> Best,
>>> 
>>> Mike
>>> On Feb 22, 2022, 10:20 +0300, Dick Roy <dickroy at alum.mit.edu>, wrote:
>>>> 
>>>> 
>>>> From: Starlink [mailto:starlink-bounces at lists.bufferbloat.net] On Behalf Of Mike Puchol
>>>> Sent: Monday, February 21, 2022 9:35 PM
>>>> To: Daniel AJ Sokolov; David Lang
>>>> Cc: starlink at lists.bufferbloat.net
>>>> Subject: Re: [Starlink] Starlink Roaming
>>>> 
>>>> 
>>>> Actually, laser links would make gateway connectivity *worse*. If we take the scenario attached, one gateway is suddenly having to serve traffic from all UTs that were not previously under coverage.
>>>> 
>>>> A satellite under full load can saturate two gateway links by itself. If you load, say, 20 satellites in an orbital plane, onto a single gateway, over ISL, you effectively have 5% of each satellite’s capacity available (given an equal distribution of demand, of course there will be satellites with no UTs to cover etc.).
>>>> 
>>>> [RR] I think to do this analysis correctly; one needs to consider the larger system and the time-varying loads on the components thereof. What you say is true; just a bit over-simplified to be maximally useful. Routing through complex congested networks is well-studied problem and hnts at possible solutions can probably be found thereJ)
>>>> 
>>>> 
>>>> 
>>>> Eventually they will go for optical gateways, it’s the only way to get enough capacity to the constellation, specially the 30k satellite version.
>>>> 
>>>> [RR] What do you mean by “”optical gateway”? An optical link from the satellite to the ground station? That would be real expensive at least power-wise and unreliable.
>>>> 
>>>> 
>>>> Best,
>>>> 
>>>> Mike
>>>> 
>>>> On Feb 22, 2022, 05:17 +0300, David Lang <david at lang.hm>, wrote:
>>>> 
>>>> 
>>>> On Mon, 21 Feb 2022, Daniel AJ Sokolov wrote:
>>>> 
>>>> 
>>>> On 2022-02-21 at 13:52, David Lang wrote:
>>>> 
>>>> 
>>>> 
>>>> They told me that I could try it, and it may work, may be degraded a
>>>> bit, or may not work at all. They do plan to add roaming capabilities in
>>>> the future (my guess is that the laser satellites will enable a lot more
>>>> flexibility)
>>>> 
>>>> 
>>>> Isn't that a very optimistic assessment? :-)
>>>> 
>>>> Laser links are great for remote locations with very few users, but how
>>>> could they relieve overbooking of Starlink in areas with too many users?
>>>> 
>>>> The laser links can reduce the required density of ground stations, but
>>>> they don't add capacity to the network. Any ground station not built
>>>> thanks to laser links adds load to other ground stations - and, maybe
>>>> more importantly, adds load to the satellite that does eventually
>>>> connect to a ground station.
>>>> 
>>>> Can laser links really help on a large scale, or are they just a small
>>>> help here and there?
>>>> 
>>>> 
>>>> My thinking is that the laser links will make it possible to route the traffic
>>>> from wherever I am to the appropriate ground station that I'm registered with as
>>>> opposed to the current bent-pipe approach where, if I move to far from my
>>>> registered location, I need to talk to a different ground station.
>>>> 
>>>> Currently there are two limits in any area for coverage:
>>>> 
>>>> 1. satellite bandwidth
>>>> 2. ground station bandwidth
>>>> 
>>>> laser links will significantly reduce the effect of the second one.
>>>> 
>>>> We know that they can do mobile dishes (they are testing it currently on Elon's
>>>> gulfstream, FAR more mobile that I will ever be :-) )
>>>> 
>>>> David Lang
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>>>> 
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