So Sony wants to fire lasers at satellites
I've got the feeling that the airline industry might want to have a word with that.
Sony on Friday launched a subsidiary dedicated to optical communications – in space. The new company, Sony Space Communications Corporation (SSCC) plans to develop small optical communication devices that connect satellites in low Earth orbit using a laser beam, and provide the resulting connection as a service. These small …
Upvoted, because there are obvious hazards if the use of laser-equipped satellites becomes a free-for-all.
However, it seems likely that limits on frequency bands, transmission power and, probably, minimum elevation above the horizon (to protect pilot's eyes) would become part of Standard Operating Procedures.
I can see both advantages and disadvantages in laser-based space comms. The most obvious disadvantage vs radio is the requirement to aim a transmission very accurately at its target to communicate at all, just as the most obvious advantage is the ability of tightly beamed transmissions to reuse any frequency without causing either accidental or deliberate interference. However, this would probably require the receiver to use a suitably directional antenna, i.e. a small telescope, and this in turn would require both ends to use rather precise pointing mechanisms to establish and use a link.
Given all the above, I can see its advantages over interplanetary distances, but wonder what,if any, advantages it would have over radio for LEO communications, other than bandwidth.
If this is satellite-satellite then eye safety shouldn't t be an issue. They are at least 300km above any pilot and are quite precisely pointed at the destination satellite.
You would need quite a chunky laser to have a Beam Hazard Distance of a satellite on the horizon 300km up. Pointing isn't a big issue, you know where the other satellite is from stored orbital data and a bit of spherical trig.
Advantage apart from bandwidth is as you say, spectrum availability. Even with narrow radio beams you are going to have some overspil and with 1000s of targets all talking at each other you are going to need quite a lot of radio channels.