How to block radiation?

[Asbo Zaprudder]

Neutrons make things radioactive because they impact the nuclei and change it to something unstable (radioactive).

Not that neutrons are a component of direct cosmic radiation in any case -- having a mean lifetime of 15 minutes or so. They would be produced by spallation when primary cosmic rays impact the heavy nuclei in shielding. They're nasty buggers really, as their Q weighting is as high or higher at all energies as protons and alpha particles (from 5 to 20), and much greater than gamma rays and electrons (1). Even when thermalised, their Q is 5. The most effective shielding for neutrons contains lots of protons, so water, paraffin (kerosene) wax, graphite, or polythene are typically used. For other types of radiation, you need high atomic number and high density materials for shielding -- ie, lead.

 

[broberfett]

Those moon landing guys went through the Van Allen radiation belt and then into open space with no protection at all. The walls of the space pod were thin. Then they walked around on the moon in little thin space suits and suffered no serious radiation damage at all. It almost seems impossible.

 

[Trekker4747]

Those moon landing guys went through the Van Allen radiation belt and then into open space with no protection at all. The walls of the space pod were thin. Then they walked around on the moon in little thin space suits and suffered no serious radiation damage at all. It almost seems impossible.

Two things:

They took the risk that radiation levels in the Van Allen belt would be low and that solar activity would be low as well. It was also purposely done when these two things were KNOWN to be at low levels.

If we were to send a space craft to, say, Mars the ship would HAVE to have some kind of shielding as the 18-month trip certainly would carry some risk of there being dangerous solar activity. As well, any base on Mars or permanent base on the Moon would have to have shielding or safe-places to hide to have protection during dangerous levels of solar activity.