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Re: Oscar-Zero anyone?




Hello Edward!

25 Dec 00 02:26, you wrote to All:

 EC> The next time NASA sends someone to the moon, lets send up a
 EC> transponder package [satellite pkg with no rocket motor] to be set on
 EC> the earth facing side of the moon.  Only 250,000 miles away and fairly
 EC> easy to track.  Half
 EC> the planet can see it at a time.  A high gain antenna pointed at earth
 EC> will take care of the extra space loss which is about 12 dB more than
 EC> AO-40 at current perigee.

Erm, this has been done to death. :-)

Firstly, the free space losses are sqr(400000/40000), or 100 (roughly, i.e.
20dB.

Secondly, due to libration of the moon, any fixed antenna pointing in our
general direction needs to have a beamwidth of at least 10 degrees, which
implies an antenna gain of not much more than many of the AO-40 antennas.
Tracking is the other option, which would lower the long term reliability of
the system.

Thirdly, how is it going to be powered? (remember the 2 week lunar night -
that's a lot of batteries and solar cells! :) ).

Then there's a host of other issues, such as thermal engineering (it gets awful
hot and cold on the Moon).

Would be rather expensive, to get it up there.

 EC> If it were part of a Moon Base, then maybe it would serve dual duty as
 EC> a morale booster like ARISS is for ISS.  Or rent out some telemetry
 EC> time for somebody's experiment.  We'd certainly would have no problem
 EC> with keps ;-)

Well, if there was a manned moon base, it would become more practical, with a
fixed power source and someone to aim very high gain antennas in the right
direction, or watch over the computer tracking system and maintain the rotators
:).

A manned moon base and possible ham station/transponder is a whole new ball
game. :)

Tony, VK3JED

.. If you can read this - my cloaking device is defective.
--
|Fidonet:  Tony Langdon 3:633/284.18
|Internet: tlang@freeway.apana.org.au
|
| Standard disclaimer: The views of this user are strictly his own.


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