Radio observatories on the Moon

> But again, by how much? What's the comparison between the delta with and
> without shielding, and the delta between the two delta-Vs involved? Can a
> millimeter of aluminum shield out radio waves, and if so, what more would be
> required for the baffle?
>

A millimetere or shielding is not sufficient for radio astronomy.

The far side of the Moon is ideal, in fact the crater Daedelus is one of
the best
candidates.

Is SSI actively doing research in this field ?

For some excellent discussions of the issues involved I would refer
readers to the
following web links:

Proposals for Astronomical Observatories on the Moon
http://www.astro.gla.ac.uk/users/yuki/
maintained by Yuki D. Takahashi
Contributor to the Lunar Farside Radio Laboratory
(IAA Study) 2002/10/11 Presentation @ World Space Congress 2002/10
New Astronomy from the Moon.

2002 Lunar South Polar Infrared Telescope, NASA study
http://socrates.berkeley.edu/~yukimoon/LSPIRT.html

Lunar Farside Radio Lab
http://www.setileague.org/iaaseti/lunar02.pdf
Lunar Farside Radio Lab - a study by the International Academy of
Astronautics. Coordinated by Claudio Maccone Member of the International
Academy of Astronautics.

IAA SETI Taskgroup: Lunar Farside Radio Laboratory
http://www.setileague.org/iaaseti/lunar.htm
Dr. Claudio Maccone, Ph.D, Italy. Vice Chair of the SETI Committee
of the International Academy of Astronautics and appointed Coordinator
of the IAA Cosmic Study on the "Lunar Farside Radio Lab"
http://www.is.svitonline.com/cmaccone/

Where on Moon?
http://www.astro.gla.ac.uk/users/yuki/where.html
Where should we lay our radio array? We want a large flat area for
a long-baseline array -- inside a crater would be ideal!

Romance to Reality: Moon & Mars mission plans
http://members.aol.com/dsportree/MM14.htm
... Hence, radio communication with Earth will often require surface
or orbital relays.
These must be designed to avoid interfering with farside radio
telescopes.