A critical limiting factor for life in space
‘Big Picture: Space Biology’ (2015)
We are fortunate to live under the protective cocoon of the Earth’s thick atmosphere and sprawling magnetic field. This prevents us from being dosed by some of the intense ionising radiation found in space. This radiation can take the form of charged subatomic particles or high-energy electromagnetic radiation such as X-rays coming from the Sun and the wider galaxy.
In the unprotected arena of space, radiation can destroy cells, by damaging cellular molecules such as DNA, and cause genetic mutations, which can lead to diseases like cancer. Astronauts aboard the International Space Station (ISS) are, for the most part, safe because they still orbit within Earth’s magnetic field. If an intense eruption of charged particles bursts out of the Sun, astronauts can seek shelter in the parts of the ISS that offer greatest protection.
The longer you are outside Earth’s magnetic field, however, the more likely you are to be affected. So for missions to the Moon and other planets, radiation is the greatest limiting factor. The Apollo astronauts on their short return trips to the Moon were lucky that they didn’t suffer any significant effects. But it takes six months just for a one-way trip to Mars, so the chances of radiation problems are higher, unless we can come up with a suitable way to protect the astronauts.
For a more on radiation and its effects, see ‘Radiation in depth’.
- Space News: Dummy astronaut shows ISS crew better protected from radiation than believed
- Physics World: Mars astronauts at risk from radiation
- NASA Space Radiation Program Element
- PDF of Radiation [PDF 112KB]