Thank you for noticing the totally unintended pun! :-)

Best,

Mike
On Feb 22, 2022, 13:37 +0300, Vint Cerf <vint@google.com>, wrote:
pun intended?
Mynaric is one of the more visible ones.

:-)

v



On Tue, Feb 22, 2022 at 5:01 AM Mike Puchol <mike@starlink.sx> wrote:
It all depends on the power. We operate FSOC terminals that can do 20 Gbps at 20km+, and are eye-safe (un-aided, if you look at one using binoculars, different story).

Power also depends on receiver sensitivity, if you can reconstruct a signal from less photons, your power requirements drop, and efficiency increases. There is a lot of research going on in this field, and there are many companies that are trying to get into the ground-to-air optical link game. Mynaric is one of the more visible ones.

Best,

Mike
On Feb 22, 2022, 12:46 +0300, Sebastian Moeller <moeller0@gmx.de>, wrote:


On Feb 22, 2022, at 10:40, Mike Puchol <mike@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@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@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@alum.mit.edu>, wrote:


From: Starlink [mailto:starlink-bounces@lists.bufferbloat.net] On Behalf Of Mike Puchol
Sent: Monday, February 21, 2022 9:35 PM
To: Daniel AJ Sokolov; David Lang
Cc: starlink@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@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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