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by Meneth12 hours ago |
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upvoteby adev_7 hours ago|
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> "low-latency links", says the article. I wonder if they consider 500 ms ping to be low, or if they want to replace Geostationary with Low Earth Orbit.

Directional laser beams are orders of magnitude to jam compared to radio wave. That alone makes it of big interest for military applications, even with 500 ms latency.

There is several known cases where jamming caused the loss of costly military drones.

https://en.wikipedia.org/wiki/Iran%E2%80%93U.S._RQ-170_incid...

Laser comms could prevent that entirely.

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upvoteby shagie6 hours ago|
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> Directional laser beams are orders of magnitude to jam compared to radio wave. That alone makes it of big interest for military applications, even with 500 ms latency.

I am reminded of RFC 1217 - Memo from the Consortium for Slow Commotion Research (CSCR) https://www.rfc-editor.org/rfc/rfc1217

    2. Jam-Resistant Land Mobile Communications

       This system uses a highly redundant optical communication technique
       to achieve ultra-low, ultra-robust transmission.  The basic unit is
       the M1A1 tank.  Each tank is labelled with the number 0 or 1 painted
       four feet high on the tank turret in yellow, day-glo luminescent
       paint.  Several detection methods are under consideration:
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upvoteby Spoom4 hours ago|
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I love that this was ostensibly written by Vint Cerf.
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upvoteby shagie3 hours ago|
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It's listed in his computer science bibliography https://dblp.org/pid/c/VintonGCerf.html and https://en.wikipedia.org/wiki/Vint_Cerf#Author

Though the edit for that authorship to the RFC came much later. https://datatracker.ietf.org/doc/rfc1217/history/

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upvoteby 5 hours ago|
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upvoteby SlightlyLeftPad5 hours ago|
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Could these not be jammed by blasting the same wavelength laser at said geostationary satellite?
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upvoteby tiagod5 hours ago|
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Please correct me if I'm wrong, but I guess if you aim well enough, there could be a very long, narrow, non-reflective cylinder in front of the receiver that would block all light that is not coming exactly from the direction of the target satellite.
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upvoteby scottLobster3 hours ago|
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"If you aim well enough" is doing a ton of work there. Precise real-time optical tracking of a satellite from a moving platform is an extremely difficult problem. Even if the satellite itself is geostationary, it would also have to rotate to keep the "cylinder" pointed in the right direction to maintain signal.

I suppose you could make a "cylinder" or "cone" broad enough that, if the threat was static, could blot-out attempted jamming from only certain regions while staying open facing toward friendly zones.

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upvoteby cyberax46 minutes ago|
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It's a geostationary sat. It doesn't move.
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upvoteby scottLobster31 minutes ago|
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No, but the airplane it would be talking to does. Hard enough when your transceiver is wide open, if you narrow your FOV to a thin cone in order to block jamming signals, the GEO now has to physically track the airplane somehow.

Either the whole satellite rotates or the transciever is on a mount that can rotate

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upvoteby vlovich12310 minutes ago|
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Unless you plan on having 1 satellite per airplane, something tells me it's harder to constrain the FOV than you might suggest. There's also the small problem of the energy, complexity, & weight of having motorized parts on the satellite (or fine-grained attitude control for the satellite itself to track the craft).
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upvoteby Onavo5 hours ago|
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You will probably need to increase the gain (better lens, photomultipliers) on the receiver photodiode too.
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upvoteby fidotron11 hours ago|
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Getting it to work with one end stationary first sounds like a reasonable development plan. LEO adds a lot of complexity, but with huge benefits.

OTOH the number of engineers that focus on throughput over latency is quite staggering.

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upvoteby amarant2 hours ago|
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Leo seems easier to me. Geostationary is really far away. Leo is much, much closer. It's easier to hit a buck thats running right past you than to hit a stationary target across the Atlantic.

Especially if you yourself are on a moving platform

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upvoteby IrishTechie11 hours ago|
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I guess if your goal is just to stream aircraft telemetry and black box like recordings then latency may not be high on the agenda.
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upvoteby connicpu10 hours ago|
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Black box data doesn't need that crazy throughput either though. Traditional RF is much easier to get right, and works even when the aircraft starts losing track of where it is and stops being able to track the satellite with its laser
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upvoteby SiempreViernes11 hours ago|
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I think it's the opposite? For small telemetry you want it now, but for the big data products there's no hope of "now" and so you settle for soon.
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upvoteby rtkwe5 hours ago|
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Geostationary is easier to hit than a LEO constellation like Starlink. With an LEO target you need to switch at least every 2-4 minutes, Starlink ground stations can switch multiple times per minute but that's for obstacle avoidance in the air you'd only have to switch when the current target moves out of LOS entirely.
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upvoteby pottertheotter9 hours ago|
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I’ll take 500ms ping for those speeds while temporarily on a plane.
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upvoteby oofbey9 hours ago|
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No doubt! I’ve measured literal 5 minute ping times on airplanes. 300,000ms. Where are the buffering the packets!?
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upvoteby raddan7 hours ago|
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My guess is that you're getting retransmissions because of dropped frames, not because there's some huge buffer in the sky.
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upvoteby reactordev7 hours ago|
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Indicated airspeed 280kts, ground speed 470kts, FL410, the packets are trying to catch up…
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upvoteby JackFr7 hours ago|
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I like "huge buffer in the sky".

That's where I imagine all my deleted data goes.

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upvoteby 0_____04 hours ago|
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we're all just riding the ring buffer of samsara, maaan
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upvoteby BobbyTables27 hours ago|
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There’s one huge buffer in the sky!

The huge buffers are at the two endpoints (:->

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