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Re: Oscar 0



>From time to time there appear proposals to put transponders or beacons
on the Moon. 

What you never see is any system analysis. 

I suggest everyone first reads the following article from James Miller,
which was published in 1994 and which is available here:

http://www.amsat.org/amsat/articles/g3ruh/110.txt
http://www.amsat.org/amsat/articles/g3ruh/110fig01.gif


It is indeed probably a good time to think about what comes after P3-D,
what do people want, what do the builders want and does amateur radio
(satellites) have a future et all?

Clearly, we need something which challenges people.. Something which
was done again and again since the last 20-30 years is not really
challenging anymore, although this does not automatically exclude
to build and launch some kind of simple satellites. But if ham radio
and AMSAT will survive in future, we need to be always a step ahead
and set examples of what can be done with the right people and the
right motivation behind it.  

So the question is: Do we want to go to Mars, or first to the Moon 
or both? Do we want a lander or do we want to go into a lunar
orbit? 

The idea of a moon repeater recently came up again in an article, which
I don't want to address further. Despite all the technical nonsense in 
the article, at least someone has a "vision".. 

Surely, a moonbased transponder or whatever would be nice project, we
have been through some technical details already before. 

Landing on the Moon is not easier than landing on MARS! 
The extreme temperature and power problems during the cold and
long lunar night is a problem for itself, without having an RTG.
Everyone can see that a linear transponder on the moon will be
very difficult to operate from earth. Imagine large parts of the
community try to uplink, only the EME type stations would have a good 
chance at the end.  I don't think that a normal transponder would
be a good idea, they are better be placed in earth orbit on Phase 3
satellites in a highly inclined elliptical orbit.
I would prefer something like a "moon weather" station which only
transmits a beacon carrying some sort of temperature telemetry and
other data, perhaps even scientific data or pictures. Imagine you
can see the blue planet from the moon as the Apollo astronaut's did
a while ago.  The camera would indeed look in the same direction as
the antennas.
The data transmission would be *very* low speed (so grabbing pictures
would take a while) and using advanced modulation/coding techniques
to ensure that even an OSCAR class station could receive the beacon.
Perhaps something like PSK31 (31.25 bps PSK) could be used, so that 
users on earth only need to have a soundblaster card for the SSB 
receiver.

These are only a few examples. Well, problems are there to be solved.. 
I personally would not totally exclude the idea to get something 
to the moon. Maybe we find the usual better cheaper AMSAT way to do it.. 
AMSAT already does have the know how to fly to Mars, so why not..
It's only a matter of motivation...


73s Peter DB2OS

(The contents of this message represent the personal opinion of the
author and are not representative of AMSAT-DL unless otherwise stated.)

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