Discussion
World-first gigabit-per-second laser link between aircraft and geostationary satellite
xnx: Impressive! I believe round trip latency would be 0.5 seconds.
1e1a: That's ~162.5 MB in transit at any time
zppln: Weird.
htgb: Shouldn't it be 1000/16 = 62.5?
cm2187: But that means you need to have a different laser pointed at every single individual aircraft right? Doesn’t really scale.
Meneth: "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.
amelius: I suppose you can do time-sharing. And use mems-mirrors to quickly move the beam between different targets.
kevincox: Excellent for pingfs (https://github.com/yarrick/pingfs)
fidotron: 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.
IrishTechie: 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.
utopiah: Nice, if you want a bit more details on the TNO side https://www.tno.nl/en/newsroom/2026/02/airbus-tno-demonstrat... relying on https://connectivity.esa.int/archives/projects/ultraair
1e1a: The article says 2.6 gigabits/second which is 2,600,000,000 bits/second, 2,600,000,000b/s * 0.5s / 8 is 162,500,000 bytes, 162,500,000 / 1,000,000 is 162.5 megabytes
SiempreViernes: 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.
db48x: Some miniaturization required.
esseph: Laser TDMA! :-)https://en.wikipedia.org/wiki/Time-division_multiple_access
connicpu: 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
htgb: Right, thanks
philipwhiuk: > Because laser beams spread far less than radio waves, they provide more secure linksBasing your security on laser diffusion seems sus.
eqvinox: You can probably do phased arrays. (It might already be a phased array.)
mohaine: Pretty sure phased array LASERs are not yet a thing.
buildbot: I was not sure, but they are!https://cga.anu.edu.au/research/activities/laser-beam-steeri...https://www.darpa.mil/research/programs/excaliburI guess in some ways even the fancy multi diode fiber lasers are phased arrays, just with the single goal of higher output power.
aidenn0: Lasers are coherent emitters; you can definitely make interference patterns with them, so I don't see why LASER MIMO wouldn't be possible, in theory.
eqvinox: Yeah but this is research, if they're to come up somewhere, where else would it be?
pottertheotter: I’ll take 500ms ping for those speeds while temporarily on a plane.
oofbey: No doubt! I’ve measured literal 5 minute ping times on airplanes. 300,000ms. Where are the buffering the packets!?
Tepix: These beams are much harder to detect and eavesdrop upon. You increase the difficulty for a remote attacker. I wouldn't stop encrypting the data, however: The Alphasat TDP‑1 has a telescope with an 135mm aperture. The beam diameter is likely to be at least 700m wide according to the diffraction limit.
tart-lemonade: > These developments entail a future where travellers could enjoy reliable, high‑speed internet while flying, and where people on ships or in vehicles crossing remote regions can stay connected without interruption.How reliable/feasible would this be on the ground? From what I understand, shining non-trivial lasers in the sky is a massive liability because of the potential to interfere with aircraft. I don't see anything about the wavelength used, but even if it's outside the visible spectrum, it would still be subject to interference from aircraft when used on the ground or at sea.
joezydeco: It's being implemented. I thought I saw that Amazon Leo (nee Kuiper) was going to lean on it pretty heavily.https://www.techbriefs.com/component/content/article/47300-u...
kipchak: There's a patent (2017/0280211 A1) for using this as a data storage method, and there was a company called Lyteloop trying to leverage the idea for data storage with estimations for petabytes across constellation.
raddan: My guess is that you're getting retransmissions because of dropped frames, not because there's some huge buffer in the sky.
JackFr: I like "huge buffer in the sky".That's where I imagine all my deleted data goes.
BobbyTables2: There’s one huge buffer in the sky!The huge buffers are at the two endpoints (:->
adev_: > "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 the 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.
nashashmi: [delayed]
kube-system: All security is based on a combination of individually flimsy ideas
rtkwe: 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.
mynameisvlad: That talks about inter-satellite links (which Starlink uses already). Parent comment asked about ground <-> sat
SlightlyLeftPad: Could these not be jammed by blasting the same wavelength laser at said geostationary satellite?
shagie: > 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:
Spoom: I love that this was ostensibly written by Vint Cerf.
voidUpdate: If starlink satellites get laser downlink, it might work :P
cm2187: laser downlink to one point, isn't it? Not to 300 moving aircrafts at once.
shagie: It's listed in his computer science bibliography https://dblp.org/pid/c/VintonGCerf.html and https://en.wikipedia.org/wiki/Vint_Cerf#AuthorThough the edit for that authorship to the RFC came much later. https://datatracker.ietf.org/doc/rfc1217/history/
burnt-resistor: I marvel at the ability to track a target in both directions ~40k+ km away while moving quickly (kinematic) considering atmospheric and relativistic effects.
tiagod: 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.
scottLobster: "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.
amarant: 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
icegreentea2: Here's a paper (from July 2025) on previous steps in this program, getting up the initial testing in flight. Maximum uplink laser power of 20W, though they got good performance all the way down to 2W. The sat has a laser pointing down that was used to help lock on, but it's not clear if it has any meaningful downlink capability, all discussions are about uplink capability. Lots a nerdy details here.https://www.spiedigitallibrary.org/conference-proceedings-of...In addition, here's a random paper on the testing performed on the space borne laser terminals - https://icsos2012.nict.go.jp/pdf/1569586689.pdfThis tells us that the laser terminals have a FOV of +/-2.5mrad in acquisition mode (so before lock on), and +/-0.5mrad in communication/tracking mode. This corresponds ~100km and ~20km radius FOV from GEO to surface.
dogma1138: Uplink alone can be significant for clandestine operations.You can have a stealth drone which is effectively invisible to SIGINT transmitting real time intelligence to a satellite whilst either operating autonomously or receiving commands via a wide area encrypted broadcast (yes I know you can theoretically detect receivers through signal attenuation but at these distances it’s effectively impossible to do).
cyberax: It's a geostationary sat. It doesn't move.
scottLobster: 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
fc417fc802: > yes I know you can theoretically detect receivers through signal attenuation but at these distances it’s effectively impossible to doWell if that's part of your threat model then you should also consider the RF put out by the motors. Remember the part where we densely blanked the inhabited parts of the world with highly sensitive antennas over the past 3 decades?
maxlin: Kinda cool but seems paltry during a time when we have Starlink, which also has space-to-space laser links between satellites, of 100-200Gbps in bandwidth.Though I suppose this is a bit safer from Kessler syndrome
sleepy_keita: They say "error-free connection", which implies 2-way communication, right?
trashb: your assuming the target satellite doesn't reflect?
Nevermark: > downloading an HD film takes only seconds.My apprehensions about living in GSO are over!The rate that comms are colonizing orbit, or I should say the acceleration rate, feels like it can’t last for more than another decade or so before hundreds of thousands of satellites become each others Kessler nightmare.But somehow, I expect systems will evolve to get much denser.it’s probable not too early to consider future ring structures, for mounted satellites? Or an optimized distribution of long parking “star-bars”. As apposed to the free for all?I expect reserved altitude shells, for space stations, depots and rocket/ship orbital maneuvers without the dodgeball.
dogma1138: You can embed parity and error recovery bits in a one way stream.This is how one way fiber optic connections for air gapped systems work.
