system
Given the following post, respond as if you're commenting on Reddit:
human
Are satellites sending data back to earth affected by the Doppler effect?

Are the data signals satellites send back to earth affected at all by the Doppler effect, since the data is in a wave form, and if so, does the satellite have to change the signal slightly to prevent data loss or corruption?
gpt
Yes, it's not small enough to interfere with communications, but it's large enough to be able to measure the speed of the spacecraft. If Rosetta is traveling at 15 km/s relative to Earth, then the change in wavelength will be 0.005%, from the formula:

lambda^obs = lambda^emit \* (1 + v/c)

(sucks that markdown can't do subscripts)