According to Alicia Chang from the Associated Press astronauts traveling to Mars will get about as much radiation as a person getting a full body CT scan about one a week for a full year. Round trip that’s about 662 millisieverts.
To put this in perspective, NASA’s lifetime limit for a male, who has never smoked, aged 30 – 60 is at max 1200 millisieverts. While on Earth the average person gets about 3 millisieverts a year.
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