Debunking the Conspiracy Theorists
The radiation in the van Allen belts and in cis-lunar space would have
killed the astronauts.
The van Allen belts are regions above the Earth’s surface where
the Earth’s magnetic field has trapped particles of solar wind.
An unprotected astronaut would get a lethal dose if he stayed in
the region long enough: the Apollo spacecraft passed through the
belts in an hour or so.
There wasn’t enough time to get a lethal dose – as well, most of
the radiation was blocked by the hull.
While in cis-lunar space, the radiation dose received by the
Apollo astronauts was only a few rems.