(Spock eyebrow) Fascinateing! I had actualy been assuming that because of the need for an antenna to be pointed at a fixed point (Earth) two structures, one sail, and one antenna, would be needed. I was asking WRT in space communications, wondering if a sail type structure unfurled in space might be more economical, long term (given that in space you don't need to maintain a large antenna against the elements as you do a radio dish on Earth, nor build and maintain large support structures, allowing an antenna to be potentially very large but very lightweight), than building a very large antenna on Earth. My thought leading up to that being that a very large antenna ( a square Km or more) near Earth could mean less power needed for communications from distant space probes, and hence more room for science payload instead of power source.
In space PR and Politics are as important as engineering and science. And no-one can hear you screaming about it.
"There are more things in heaven and earth, Horatio, Than are dreamt of in your philosophy."
Exploring other worlds with people is a great idea, but look at what has happened since the end of Apollo: How much could unmanned exploration (and astronomy) have discovered with all that money blown on paper rockets?