A reason to go to Mars

In order to shield a habitat from the most penetrating cosmic rays,
you need about 5 meters although I have heard some figures as high as
20 feet. NASA, for some reason, has only recently in the last few
years become fully concerned about the dangers of cosmic radiation
beyond Earth's magnetic field.

Its going to be pretty easy to find mass shielding on the Moon, Mars,
and the asteroids. But its going to be pretty tough finding-- light
weight-- shielding for interplanetary travel. Hopefully those magnetic
or electrostatic field concepts will work in the near future for
interplanetary space craft, or most space travelers are going to end
up getting their safe lifetime dose of radiation on just one trip to
Mars or to an asteroid.

Marcel F. Williams

--- In spacesettlers@yahoogroups.com, "sailor.barsoom"
wrote: