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.
This 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.
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).
> yes I know you can theoretically detect receivers through signal attenuation but at these distances it’s effectively impossible to do
Well 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?
> "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.
> 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.
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:
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
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.
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?).
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.
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.
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.
> 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.
I marvel at the ability to track a target in both directions ~40k+ km away while moving quickly (kinematic) considering atmospheric and relativistic effects.
Readit News
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.pdf
This 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.
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).
Well 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?
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.
I am reminded of RFC 1217 - Memo from the Consortium for Slow Commotion Research (CSCR) https://www.rfc-editor.org/rfc/rfc1217
OTOH the number of engineers that focus on throughput over latency is quite staggering.
Especially if you yourself are on a moving platform
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.
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.
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://news.ycombinator.com/item?id=46709548 - Discussion from a month ago with several links for a recent example.
https://www.techbriefs.com/component/content/article/47300-u...