How is NASA going to reduce radiation exposure for astronauts on the Mars mission?

A few ways... most interesting - using the walls for water storage. Water will stop many kinds of hard particles, and a layer of water in the walls will be one shield. For solar events, pointing the bulk of the spacecraft at the sun (the heat shield, the service module, fuel, engines) will reduce much of the ionic bombardment they were afraid would happen to Apollo on it's way to the moon.

For some radiations - there's not much that can be done... cosmic rays can be reduced, but not eliminated.

1) The shielding from the "skin" of the craft will be sufficient for "normal" exposure.

2) on days when the radiation level increases due to Coronal Mass Ejections (CME) by the Sun - takes 3 to 5 days for the excess radiation to travel from the Sun to Earth, a a bit more to get to Mars - most plans call for a special room with extra shielding deeper inside the craft. The room will be big enough to shield the crew for the duration of the elevated level of radiation, but too small for continual living.

3) Shielding the entire craft would be too expensive (and add too much mass).

4) It will not be NASA (or, at least, not NASA by itself) but a consortium of space agencies that will participate in the program (NASA + ESA + Roscosmos + who knows who else, by that time).

There has already been discussions about these kinds of things - even though nothing has been built yet.

HEY! Stop cheating. That's the $29,000 question. If you win are you planning to share your winnings with the people who helped you on this site?

To those who would answer, why get 10 points when you could get $29,000 ?

http://news.yahoo.com/nasa-pay-29-000-173100729.ht...

BTW NASA has already thought of lead lining but you can't just say lead lining you'd have to find a way (within a reasonable budget) to design a system that can launch something so heavy. Look how big the Apollo's Saturn V rocket was to launch that thin flimsy little Lunar Module.

Lead suit.