DARPA is seeking proposals for projects to investigate ways to mitigate the health effects of ionizing radiation: DARPA Seeks to Defuse the Threat of Ionizing Radiation – DARPA

DARPA releases request for information on novel approaches to mitigate immediate and long-term health damage from acute exposure to ionizing radiation and model its biophysical effects

The program is aimed at dealing with terrestrial situations but if it results in useful treatments, the would be useful for space explorers and settlers if they are subjected to high radiation doses when exposed to a solar flare event with insufficient shielding.