http://www.msnbc.com/news/577974.asp?0nm=O14O

Developing an interplanetary communications infrastructure is a good idea. For example, if we can deploy a series of comminications satellites around Mars like what's being proposed with the Mars Internet, each individual orbiter, lander, and rover wouldn't have to carry the extra weight required to communicate at a high data rate all the way back to Earth. Each vehicle would only have to have a communications system capable of communicating with the satellite constellation. This would lower vehicle weight and cost considerably. I also like the article's point about having other relays around Venus or Mercury to allow communications with Mars vehicles when the Sun is in the way of direct line of sight.

Some are advocating adding a GPS-type navigation capability to the communications satellites. This would be very helpful for rovers and sample return missions. It could also be very useful for precise guidance to specific touchdown points for landers.