[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.