Communicating effectively with astronauts on the moon was an essential part of the Apollo missions. Without reliable radio contact there would have been no live feed of Armstrong's first steps and in all likelihood no first steps at all.
According to new research, the next footsteps on the lunar surface could be beamed back to Earth via the moon's very own network of communication satellites. The setup could double as a GPS for moonwalkers.
More: http://www.space.com/businesstechnology/080430-tw-lunar-communication-post.html