NASA to irradiate monkeys to study effects of long space trips on humans The Telegraph

It will be Nasa’s first experiment on primates in decades.
If a manned mission to Mars ever takes place, the human pilots will be outside Earth’s protective magnetic field for several months, unprotected from solar radiation. Little research has been done on this sort of long-term exposure to low doses of radiation. Rats and mice have been exposed to this sort of radiation before, but that gives only a hint of what the effects would be on humans.
Eleanor Blakely, a biophysicist at Lawrence Berkeley National Laboratory, said: “Obviously, the closer we get to man, the better.”