Decreasing solar activity could make the journey to Mars and back riskier for astronauts, a new study warns.
The sun’s magnetic field acts as a barrier to high-energy galactic cosmic rays, which originate outside the solar system in supernova explosions. The magnetic field is stronger when the sun is more active, deflecting more of this potentially dangerous radiation.
But the last “solar minimum,” which occurred in 2009, was the weakest ever measured in the space age, and some scientists believe solar activity is going to weaken further — which would be bad news for manned missions through deep space.
The new study, which has been accepted for publication in the journal Space Weather, found that a 30-year-old male astronaut who flew to Mars during a period of low solar activity would surpass NASA’s radiation safety limits in less than 400 days, which is barely enough time to get to the Red Planet and back. (A female would reach the limit in under 300 days.)