Being on Earth, seeing the blue sky it is hard to believe that
terrestrial weather is influenced by space weather. But nothing
could be more true. Weather on a terrestrial planet such as the
Earth and Mars is restricted to the small gaseous envelope we call
the atmosphere. The atmosphere is constantly being bombarded by
cosmic radiation and solar wind. But occasionally enormous amounts
of mass are erupting from the sun, called coronal mass ejections
Lucky for terrans only a small amount of these life threathening
particles make it to the surface. This is because the Earth has
a magnetic field bending off the ionic particles present in the
solar wind, CME's and the cosmic radiation. Another radiation blocker
is the ozone layer, located high in the upper parts of the atmosphere.
It contains the gas ozone [O3] which blocks
UV radiation. Mars doesn't have a natural magnetic field anymore
and the atmosphere at sealevel is 150 times thinner than on Earth
[~6 mbar]. Therefore Martians need to stay sheltered and protected
against the sun and cosmic radiation as much as possible.
Travelling beyond Earth means leaving our natural protector. In
space: on the Moon, on Mars, in the Asteroid Belt and at all the
other ExTerra locations we need artificial protection against radiation.
The artificial protection scientist came up with is just plain water.
Water has protected life all it's evolutionary history and continues
Protective radiation shelters can be found on all colonized ExTerran
worlds. On Mars, for example, most of Areopolis is built underground.
After the 2012 Sun Storm event radiation protection standards have
been devised for mechanical engineering and architectural designs.
The roof of a Mars rover for example needs to have a 10 cm water
layer. The 2012 Sun Storm was the highest Solar activity ever measured,
lasting one month. Since this event ExTerra infrastructure needs
to satisfy very tight post-2012 radiation protection guidelines.