"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.
fidotron 4 hours ago [-]
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 3 hours ago [-]
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.
connicpu 2 hours ago [-]
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
SiempreViernes 3 hours ago [-]
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.
pottertheotter 1 hours ago [-]
I’ll take 500ms ping for those speeds while temporarily on a plane.
oofbey 50 minutes ago [-]
No doubt! I’ve measured literal 5 minute ping times on airplanes. 300,000ms. Where are the buffering the packets!?
tart-lemonade 2 hours ago [-]
> 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 39 minutes ago [-]
It's being implemented. I thought I saw that Amazon Leo (nee Kuiper) was going to lean on it pretty heavily.
I guess in some ways even the fancy multi diode fiber lasers are phased arrays, just with the single goal of higher output power.
aidenn0 1 hours ago [-]
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 1 hours ago [-]
Yeah but this is research, if they're to come up somewhere, where else would it be?
voidUpdate 3 hours ago [-]
If starlink satellites get laser downlink, it might work :P
myrmidon 5 hours ago [-]
I'm really curious how the tracking works in such a system, and how "bad" the beam spread is (my impression is that from the diffraction limit alone the beam has to be spread over at least a ~10m radius after travelling 36000km).
Some info on the laser itself would also be very interesting (power? wavelength?).
Really cool project though!
amelius 4 hours ago [-]
> and how "bad" the beam spread is
The spread makes the tracking easier, I suppose.
TimorousBestie 3 hours ago [-]
Perhaps a little, however. Different paths through the atmosphere will perturb the phase of the signal; depending on conditions not all of that ~10m beam width is going to decode with an acceptable bit error rate.
mytailorisrich 2 hours ago [-]
Tracking and actuation is nothing new or particularly challenging, IMHO. It's the laser/optical part combined with throughput at that distance that is the main area of R&D, I think.
xnx 6 hours ago [-]
Impressive! I believe round trip latency would be 0.5 seconds.
That could you used like RAM like the delay-line memory used by early computers!
htgb 5 hours ago [-]
Shouldn't it be 1000/16 = 62.5? Impressive nonetheless, of course!
1e1a 3 hours ago [-]
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
htgb 1 hours ago [-]
Right, thanks
zppln 5 hours ago [-]
Weird.
philipwhiuk 59 minutes ago [-]
> Because laser beams spread far less than radio waves, they provide more secure links
Basing your security on laser diffusion seems sus.
Tepix 38 minutes ago [-]
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.
Schlagbohrer 56 minutes ago [-]
It's worth it as another layer of security. The beam width being so narrow means even intercepting it becomes harder. This is more relevant for down-to-earth links where the spot hitting the earth is so narrow it could be confined withing a geographically controlled area, rather than hitting an entire continent like longer wavelengths do.
Rendered at 16:46:52 GMT+0000 (Coordinated Universal Time) with Vercel.
OTOH the number of engineers that focus on throughput over latency is quite staggering.
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.
https://www.techbriefs.com/component/content/article/47300-u...
https://news.ycombinator.com/item?id=46709548 - Discussion from a month ago with several links for a recent example.
https://en.wikipedia.org/wiki/Time-division_multiple_access
https://cga.anu.edu.au/research/activities/laser-beam-steeri...
https://www.darpa.mil/research/programs/excalibur
I guess in some ways even the fancy multi diode fiber lasers are phased arrays, just with the single goal of higher output power.
Some info on the laser itself would also be very interesting (power? wavelength?).
Really cool project though!
The spread makes the tracking easier, I suppose.
Basing your security on laser diffusion seems sus.