International space station connects 100Mbps symmetric space laser ethernet using Sony optical disc tech The Japan Aerospace Exploration Agency (JAXA) has achieved a 100 Mbps ethernet connection from the International Space Station to earth, using lasers! The feat was accomplished using a widget called SOLISS - the Small Optical Link for International Space Station – that went aloft in late 2019 and was then installed on Japan’s …
But for space-to-space communication, they should find a better compromise between sender and receiver size. Adding 1 m receiver telescopes to satellites sounds like an expensive proposition and might not be competitive with simple radiowave antennas. Having a 1 m telescope on earth is, of course, much simpler.
In the end, lasers will only be superior if you require the spatial collimation of the laser beam for directional transmission. This comes with a cost because modulating signals onto a laser beam is rather inefficient as compared to transmitting the same signal directly through an antenna. It'll be interesting to see where this technology goes. On earth, laser communication has been proposed many times -- but real-life applications seem rare.
I suspect you meant free space optics (FSO), i.e. firing laser beams for communication through the air.
It is available, used and can provide high capacity links, but it is very susceptible to weather (fog, rain, snow, even heat), particularly as the distance increases, meaning that other technologies are far more common. Today, E-band and V-band point to point radio links are relatively inexpensive and typically perform better, and with more and more fibre becoming available, fixed line connections increasingly substitute wireless technology for longer distance communications.
Agreed, though earth to anywhere still has to get out of the atmosphere.
Radio link to a satellite relay station to minimise disruptions from weather, with tight-beam laser link to moon/Mars/wherever seems a better choice. Allowing for chance occlusions by passing satellite/debris/asteroids/etc.
But what do I know? I'm no ---->
If you mean free-air laser communications, probably not as rare as you think. My company had two buildings on opposite sides of a main road, and we connected their LANs together via a laser link on each roof. Far more practical & cheaper than putting a wire over or under the road, and proved to be very reliable. Our link was over just a few 100 meters, but I believe the stated range of the units was 5km (line of sight, obviously). I have seen quite a few examples of the same thing once I started looking. It's frequently used between buildings on a campus or industrial estate as a cable link would exceed the max ethernet cable length and also require expensive digging to lay a duct.
Many short range ad-hoc military communications are done via free-air laser links (vehicle to vehicle or ship to ship for example), as a tight laser beam cannot be intercepted or jammed.
The lack of jamming (as opposed to just blocking the beam) in space is less of an issue, lasers allow bandwidth across frequencies to be used more than once at the same time not very far apart (at orbital distances) without interference.
For comms between the inner planets latency variation is going to be measured in tens of minutes over the distances involved and there will be a need for relays for when the LOS gets a bit close to that large bright object in the middle of our solar system.
Big difference between experiencing interference and being jammed. (Old Crow here) Interference is incidental/accidental disruption of your signal by noise (actual random noise or someone else's coherent signal) from one or more natural or generated source(s), jamming is a deliberate disruption of your signal by an adversarial actor. Some of the same methods are used for mitigation: other, more technical and/or nuanced, methods are needed to counter jamming.
Difficult to jam laser comms. Typically, a CW laser diode is modulated by varying the current of its power supply. A modulation signal will be generated digitally and a DAC and amplifier will be used to drive the modulation of the current source. An optical notch filter allows a narrow range of wavelengths through to the detector. A high speed ADC directly converts the received signal to a digital signal, then a FPGA performs mixing and filtering mathematically. A QAM modulation scheme is typical. A sideband control channel would likely use a PSK modulation and could easily be used to switch carrier frequency at random.
A CW light source would show up as a DC offset, so a CW jamming signal would have to be intense enough to saturate the detector. Since the sun can't even do that, we can rule that one out. The jammer would need to know the precise wavelength and carrier frequency and would have to be able to decrypt the control signal to detect carrier frequency changes.
I used it between two buildings because they only put one duct in when the built the second site, only problem was the fixed link failed and it was running on the laser. Nobody had noticed and we got a day of freezing fog, when refracted the beam so it couldn’t reach the other side.
We had to go over to the site and when we got there you couldn’t see either building from the road (60 feet from the kerb).
I recently put a point to point radio in for another site and these days it is a lot more reliable and just as fast
I'm not sure where you're getting the 1m figure from. According to the graphic the 1m telescope is on the ground and the unit on the ISS has an aperture of roughly 50mm. I assume the system is reversible (I can't see why it wouldn't be) so the larger unit will always be on Earth.
I’m sure the ISS will be able to hook into star links backhaul and gain global coverage and higher bandwidth before Sony get their toy working globally for ISS.
Or did someone watch that awful brad pit AdAstra movie and decide they needed to build an encrypted laser link so they can go to Mars and then send a live encrypted voice laser communication to the outer solar system? Not sure it was worth the journey or the lives lost along the way to send a voicemail.
I pretty sure I recall many years ago, when dinosaurs roamed the earth we all thought this new USENET thing was a neat idea, someone issued one of the traditional Apr 1 spoof RFC's (hopefully issued via kremvax!) proposing an extenstion of the domain naming system to add an extra level of domains above the .com/.net/.edu/.org/country level to indicate the planet where the domain was based (or orbiting) along with rules for how subdomain levels would be added for moons, what the criteria for asteroids (nb this was before the "is Pluto really a planet" debate!) having domains would be and how domains of spacecraft were handled. So, I think all the relevant preparatory work is in place.
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