The Moon

The moon was fairly impressive looking this morning. I spotted it as I was getting into my car on the way to work. Being a Amateur Radio operator, I was wondering why no one has put a repeater on the moon. It appears that there are several reasons.

I was reading a Journal I get from AMSAT and apparently, the moon is a terrible place for a communications relay (for earth anyways). According to Phil, KA9Q As it is so far away, about 400,000 km. Which is over 10 times the distance of a geostationary satellite, the path loss would be 20dB greater that that to a geostationary satellite. That’s only 1% of the received signal power for the same transmitter in geostationary orbit. Also, the round trip propogation delay is about 2.7 seconds, which would make casual conversation quite difficult (quite apparent on the Apollo mission communications).

Its apparently more difficult to land on the Moon than on Mars, also on most of the Lunar surface it gets dark for 2 weeks at a time reaching temperatures somewhere around -200 degrees, surging to +200 in sunlight. Though there are apparently a few places near the south pole of the moon that are in almost permenant sunshine (bring your factor 30!).

Loads of information on the moon and Lunar missions can be found at this site.