# Max. speed that a space probe can communite with the Earth? [closed]

Question: Which is the average or maximum speed of a telematically sent message that a space probe can send? Is as simple as radio waves travel at the speed of light in a vacuum?

Context: I have been asked to make a first estimation about how much time is needed to send a space probe and then receive the signal.

I am supposing that the space probe is sent at $15 \ km/s$ but I have not idea of the telematic signal speed.