Using Concrete to build space ships...

--- In ssi_list@... "Ed Minchau"

> You need the same mass no matter what you use as shielding. To
get
> the same level of radiation as sea level on earth, you need
> 101kPa/9.8(m/s^2) = 10300kg of shielding per square meter.

Just to clarify two points. First, it's not the total mass we're
worried about, it's the mass/area, which you do make mention of, but
you would have a smaller circumference by having a shielded *barrel*
inside the ship in which the crew lived. Outside the barrel would be
the other functional areas. This way, the larger circumference of
the ship doesn't have to be covered, therefore less overall mass.

Second point, it's not the total mass/area, it's the radiation
stopping power of that mass. Hydrogen containing compounds are more
effective, so if it was pure LH2, you wouldn't need 10,300 kg/m^2,
less would do.

Overall, though I take your point.

TangoMan