Has anyone considered the notion that the communications from a HEO or Moon or Mars need not be analog? Has anyone considered a digital mode such as WSJT for comms? I know for a fact people are running meteor scatter and EME using a single beam (albeit a long one) and 150 watts. This is not out of the reach of most hams and it is not non-viable communications mode... Heck the US Navy even ran RTTY in the 60's from Hawaii to Maryland as a normal mode of communications (yes it was big and wieldy, I just mentioned it as an aside).
DE - KD1PE - Jack
Why go with the minimal antenna gain? ... any antenna with a 3 db point that exceeds 6.5 degrees is just wasting transmitter power.
I think that would be about a 24 dB gain antenna. Pretty big and would take some careful alignment... Kinda like a realy big EME array
Just remember what an Oscar 10 station took to have reliable communications, At Apogee it was only 35,000 miles away, the Moon is ...] [250,000 miles]
Which is 7 times farther, squared or 50 times more power (about 17 dB).