Free_Astronomy_-_SeptemberOctober_2019

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ASTRONAUTICS

S

upernovae,

like the one

depicted below,

are the main

sources of galac-

tic radiation that

enter our Solar

System and di-

rectly affect the

spacecrafts that

travel beyond the

magnetosphere.

[ESO/M. Korn-

messer]

All of these experimental inconsistencies

and various other environmental consider-

ations give uncertainty to the results of

space radiobiology studies, making them

only partially usable for extrapolating and

predicting the clinical consequences for as-

tronauts. This is not encouraging, as health

risks associated with exposure to space ra-

diation will become even more relevant

when future manned missions require

transfers far beyond low Earth orbit and

well beyond the protection of our magne-

tosphere. So far, only 27 astronauts have

exceeded these limits – all during the

Apollo program – and have done so only

for a few days, a statistically negligible

sample for providing meaningful informa-

tion about the effects of space radiation on

the human body. About 530 astronauts

have operated in low Earth orbit for ex-

tended periods, where only long and/or re-

peated stays can be considered risky ( 50

astronauts have exceeded 330 days aboard

space stations).

Despite the protection offered by the mag-

netosphere, an astronaut in orbit accumu-

lates about 200 times more radiation than

an airline pilot or a nurse in a radiology unit.

On a mission to Mars, astronauts would be

subjected to a dose of radiation 700 times

space radiation EN_l'Astrofilo 29/08/2019 15:44 Page 43