[noloqy]

Compensating for the movement in the way you mention it shouldn't be too hard I guess.

I'm curious if they will need to compensate for the speed differential between the source and the target. Can anyone explain if the following will cause any problems for this technology? If the source and target move away from eachother quickly, the target will observe an increased wavelength, and vice versa. Apparently this is called Redshift [http://en.wikipedia.org/wiki/Redshift] and technically there is some similarity to the Doppler effect.

[Sharlin]

The Doppler effect (of which redshift is a special case) already has to be taken into account with radio communications (which is EM radiation just like light). In fact, all data from the Huygens Titan lander was almost lost because the software onboard the Cassini probe, on which Huygens piggybacked, couldn't have locked onto the lander's carrier wave due to too steep a Doppler shift. This was fixed by altering the Titan approach trajectory so that the Huygens' relative velocity didn't grow too high.

[lucaspiller]

The Doppler effect will be present, but will not cause any problems that aren't already present. It exists in current radio communications - light is no different in that regard as it's all just electromagnetic waves.

[nathan_long]

Would that matter if the information weren't encoded using the wavelength? Eg, imagine that they toggle the light very quickly, Morse-code style, to encode messages. If the frequency changes slightly, no big deal.

EDIT: I suppose this effect could make the speed of the toggling appear faster or slower, but that could be adjusted for.