the longest human exposure ever to cosmic rays

(which are physical particles with mass, not waves, moving at 99.999~9x21% the speed of light) which space is flooded with

was set by the 75 hours of a lander on the moon with 22 hours of those in moon walks

(space-walks in earth orbit, longest was 9 hours)

when NASA inspected the helmets of the moon walking astronauts, they found deep microscopic grooves which often made it completely through the protection

this is why moon walking astronauts reported seeing bursts of light even with their eyes closed

when they simulated comic rays hitting mice for days, the mice slowed down, learned things much slower and forgot things much faster, their brains and CNS were being damaged

humans will never make it to Mars, forget surviving on the surface, without advanced protection from cosmic rays, technology that does not exist yet

this vest is a great start but it's not enough