Since the desert environment is most reminiscent
of that of several barren, apparently lifeless planetary
bodies, deserts have been used as simulators
for testing planetary exploration equipment. For
example, NASA conducted experiments in US
southwestern deserts to test communication
rovers and to improve human-robot interactions
in conditions similar to those on the Moon and
Mars (Volpe 1999). The Nomad robot, designed for
long-distance planetary exploration, successfully
traversed the Atacama Desert, and a remotelyguided
rover explored the distribution and diversity
of life in this desert as an analogue to Mars, not
only because it is extremely dry, but also, because,
like Mars, it experiences high levels of ultraviolet
radiation, due to its altitude and atmospheric
transparency (Wettergreen and Cabrol 2005).
Just as deserts are used for research that helps
to send vehicles and sensors to explore distant
planets, meteors arrive on earth from outer space;
here deserts play a role too, serving as a repository
of space debris and meteors reaching the planet's
surface and remaining there as meteorites, wellpreserved
due to the slow rate of desert rock
erosion. Indeed, most collected meteorites have
come from deserts, though many are now also
collected in Greenland and Antarctica.
Unlike the use of deserts for testing technologies
for space exploration and for detecting meteorites,
astronomical observations can theoretically be
conducted in any environment, but conducting
them in deserts is advantageous. This is because
the background "noise" relative to the "signal"
emitted by faint celestial sources is minimized
in deserts, except where and when dust storms
are often generated. This is because, beside the
obvious low cloud cover, deserts minimize light
pollution from human settlements, atmospheric
water vapour, and air turbulence close to the
telescope. It is easy to find desert sites where
flat, treeless areas reduce the turbulence of
airflow and in which urban encroachment is
highly unlikely. Indeed, some of the largest and
most expensive astronomical instruments of the
international astronomical community are placed
on desert mountain tops, where also the layers
of atmosphere present between the telescope
and any celestial object are minimized, such as,
for example, the Very Large Telescope array (VLT)
of the European Southern Observatory (ESO) on
Cerro Paranal in the Atacama high desert of Chile,
the Sutherland site in the Karoo of South Africa where the SALT telescope started operations in
2005, and other observatories currently being
planned for other desert sites.
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