ASTRONOMERS are taking the search for somewhere quiet to work to new extremes
with a plan to put a radio telescope on the far side of the Moon.
The advantage of this unusual location is that the Moon would act as a
massive shield, protecting the telescope against radio emissions from Earth.
Astronomers could also listen to low radio frequencies that don鈥檛 penetrate the
Earth鈥檚 atmosphere.
Claudio Maccone, an astronomer at the Centre for Astrodynamics in Turin,
Italy, is assessing the concept for the International Academy of Astronautics.
He even has his eye on a plot of lunar real estate. A 100-kilometre-wide crater
called Daedalus should provide enough space, he says. The crater鈥檚
3-kilometre-high rim should also help block any stray radio signals that creep
around the Moon to the far side.
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鈥淚 do believe this will be built,鈥� says Maccone, although he admits it will
probably take at least 15 years. Even if robots were used to build the
observatory remotely, it would cost billions of dollars and need the backing of
a large space agency like NASA or the European Space Agency.
By the time the telescope could be built, the area of the Moon that鈥檚
protected from radio waves is likely to be shrinking fast. This is because as
orbit space for telecommunications satellites gets used up, they will have to be
placed in higher orbits, so their radio emissions will reach more and more of
the Moon鈥檚 surface
(see Graphic).FIG-23240501.jpg
So Maccone also wants to give the region around the Daedalus crater some form
of protection status, to create a permanent quiet zone that would be safe no
matter what technology is developed in the future. 鈥淭he far side is in my
opinion a unique treasure that should be preserved for the sake of humankind,鈥�
he says.
Setting up such a zone would probably be the responsibility of the
International Telecommunications Union, which allocates the rights to use
different radio frequencies. But it鈥檚 far from clear whose permission would be
needed to build a permanent structure on the Moon.
Maccone is due to present the results of his study to the International
Astronautical Congress next October. If the plans are approved, the first step
will be to design a satellite probe to orbit the Moon and check there really is
a quiet zone.
