T
here are dif-
ferent types
of lethal radiation
sources within a
typical galaxy:
from the occa-
sionally active
galactic nucleus
(illustration
above) to the
much more mod-
est but frequent
superficial erup-
tions of stars
(video on the
side). Whatever
the source, radia-
tion always has a
deleterious effect
on any known
lifeform that is
more-or-less di-
rectly exposed to
its flow. [NASA]ries of radiation exposures that astronauts
undergo in their careers, subjects are usu-
ally exposed to single flows of greater
overall intensity and much lower duration.
Add to this the fact that studies of the pos-
sible effects of space radiation on astro-
nauts usually do not take
into consideration the
complex energy spectra
and diverse ionic compo-
sition of the space radia-
tion environment, but
are limited instead to
assessing exposure to
mono-energetic beams
composed of restricted
types of particles or even
of just a single type. In
contrast, space missions
are faced with a hetero-
geneous zoo of particles,
all with very different
energy levels.survivors of nuclear power plant accidents
and atomic bombing. These forms of total
body radiation at high dosages for short
periods are not those typical for space
flights. The same thing can be said for ani-
mal experiments, where, to simulate a se-space radiation EN_l'Astrofilo 29/08/2019 15:44 Page 42