pun intended? Mynaric is one of the more visible ones. :-) v On Tue, Feb 22, 2022 at 5:01 AM Mike Puchol 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 , wrote: > > > > On Feb 22, 2022, at 10:40, Mike Puchol 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 , 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 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 , 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 , 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 > _______________________________________________ > Starlink mailing list > Starlink@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/starlink > > _______________________________________________ > Starlink mailing list > Starlink@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/starlink > > > > _______________________________________________ > Starlink mailing list > Starlink@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/starlink > -- Please send any postal/overnight deliveries to: Vint Cerf 1435 Woodhurst Blvd McLean, VA 22102 703-448-0965 until further notice