From the top of the atmosphere to the surface of Mars is 7-minute journey. Yet it takes 14 minutes for the signal from Mars to reach Earth. So by the time NASA gets word that Curiosity has reached Mars atmosphere, the rover will have been waiting (or destroyed) for 7 minutes already. Which means the whole process of landing on Mars is completely automated (as if it weren’t complex enough!).

Challenges of Getting to Mars: Curiosity’s Seven Minutes of Terror