Mars' thin atmosphere -- and lack of magnetic field -- lets many charged and neutral particles through.
Curiosity rover's Radiation Assessment Detector (RAD) instrument will check to see if astronauts could work there.
Credit: Southwest Research Institute.
Why the surprise? So far, it was expected that Mars, having a very thin atmosphere and no magnetosphere, would represent a rather harsh environment when it comes to cosmic radiation.
On Earth, the atmosphere and magnetosphere work as a powerful shield protecting terrestrial life. With the Martian atmosphere being only 1 % of the terrestrial one, it seems there was reason to be concerned.
These presumed high radiation levels would pose a significant threat to potential future astronauts travelling to Mars.
Moreover, they might be able to prevent the existence of any sort of Earth-like lifeforms on the planet.
Hassler was reluctant to reveal further details as he believes additional verification of the data needs to be carried out.
As the first radiation measurements ever carried out on the surface of another celestial body suggest, the radiation levels Curiosity detected on Mars are about the same as those experienced by crews aboard the International Space Station.