You may not be aware that Iridium has been doing inter-satellite links since the late 90s. Using optical rather than RF doesn't really change the game that much.
> Using optical rather than RF doesn't really change the game that much.
The precision required for aiming is directly related to the wavelength. Iridium NEXT satellites use Ka band with a wavelength around ten millimeters where anything light related has a wavelength measured in hundreds of nanometers.
The forward/backward links are a lot easier than the inter-plane links, but it's still not trivial because you're trying to hit an object the size of a small car with a laser from over 1000 miles away. Not impossible by any means, but there's not a lot of margin for error when they're looking to be able to transfer around 100 gigabits per second over this link. Other FSO systems work at significantly lower bandwidth and/or shorter range. That's not even getting in to the inter-plane links, where the target is constantly moving even in a relative sense.
You'd need an excessively powerful transmitter to use an omnidirectional antenna. In the context of a satellite, where power efficiency is crucial, it makes much more sense to use a lower-power transmitter and a directional antenna / beamforming.
A bit? It doesn't really change the nature of the problem, just the tolerances. It's nowhere near the intractable problem that some people make it out to be.
I mean, we are all aware each extra 9 of precision/uptime/etc. is far more expensive than the last. If the lasers require an order of magnitude more precision (and I could imagine it being higher), it would be a far far harder problem.
