Originally Posted by pibbur who
Yepp. And atrophia of bone and muscle tissue, but that can be compensated. Radiation, however - ouch.

pibbur

For deep space missions the problem of muscular atrophia and bone decalcification can be eliminated entirely by rotating the ship. As you said though radiation is a much more significant problem that requires additional technologies and/or incredible expenditures to provide adequate shielding (ie, a wide but hollow hull filled with individual compartments of water combined with traditional high-atomic-number shielding material). With sufficient power supply, we do have some experimental technologies that may be able to provide a less brute-force method of shielding by use of tunable plasma+electromagnetic fields enveloping the craft/habitat.