We Finally Know How Much Radiation There Is on The Moon, And It's Not Great News - ScienceAlert

"The radiation of the Moon is between two and three times higher than what you have on the ISS (International Space Station)," co-author Robert Wimmer-Schweingruber, an astrophysicist at the University of Kiel told AFP.

"So that limits your stay to approximately two months on the surface of the Moon," he added, once the radiation exposure from the roughly week-long journey there, and week back, is taken into account.​.

There are several sources of radiation exposure: galactic cosmic rays, sporadic solar particle events (for example from solar flares), and neutrons and gamma rays from interactions between space radiation and the lunar soil.