"For astronauts, however, there is one danger in space that does not end when they step out of their spacecraft. The radiation that permeates space-- unattenuated by Earth's atmosphere and magnetosphere--may damage or kill cells within astronauts' bodies, resulting in cancer or other health consequences years after a mission ends."
"An experimental drug helped protect mice and monkeys from the damaging effects of radiation, researchers said on Thursday, in a finding that may lead to less toxic cancer treatments or an emergency treatment for radiation exposure."
An Agonist of Toll-Like Receptor 5 Has Radioprotective Activity in Mouse and Primate Models, Science (subscription)
"... Supported by grants CA75179 and AI066497 from NIH and grants from NASA (U.S. National Aeronuautics and Space Administration)"