Cosmic Rays...Then and Now

I was watching a program the other night.....

Astronauts from early space missions were discussing a visual phenomenon.
They would see streaks of very bright light if they closed their eyes and
relaxed.
Later, scientists explained that the astronauts were seeing cosmic rays, and
showed
a microscopic view of an astronaughts helmet, with thousands of tiny
protrusions in the
helmet. The astronaut said, "wow, I wonder what would happen to me if I were
here
a really long time."

So, I was wondering. What does happen to an astronaut after a really long
time?
Are spacecraft and helmets better designed to protect from cosmic rays?
Although I say this program recently, it was not produced recently.
Any thoughts?

Thanks,
jojo