What if there were natural protections against cosmic rays on Mars?

The study, entitled “Directionality of the Martian Surface Radiation and Derivation of the Upward Albedo Radiation ”was published in Geophysical Research Letters. The lead author is Guo Jingnan of the University of Science and Technology of China. When MSL Curiosity landed on the surface of Mars in 2012, it carried in its payload an instrument called the Radiation Assessment Detector (RAD), which can detect and measure harmful radiation on Mars that comes from the Sun and other sources. Among the areas studied there is precisely the Murray Buttes region, on the lower Mount Sharp, in the Gale crater.
The data collected showed that near the butte there was a reduction in the radiation dose of about 5 %, but they obviously couldn't explain why. The explanation is rather complex and depends on the characteristics of the planet, essentially devoid of atmosphere. Basically the radiation hitting things, or people, on the surface of Mars comes from space, but some of it is albedo radiation, which means it is reflected off the surface, hitting objects from below.
Man on Mars, graphic illustration. In short, the radiation dose on the surface of Mars is not consistent, but it fluctuates and the heliospheric changes can affect its trend, as well as the angle of the sky to which any explorer can be exposed. A steeper angle means that the radiation has to travel through more atmosphere, which changes the surface exposure.
The orbit of Mars changes its distance from the Sun, which also affects surface radiation. Lower altitudes will be exposed to less radiation than higher altitudes. And the radiation is not a homogeneous phenomenon: there are protons, alpha particles, ions of various elements, neutrons and gamma rays.
Overall, the study helps to paint a more complete picture of the Martian radiation environment. There is already a lot of talk about placing bases in lava tubes, where people would be protected by meters of Martian regolith. But astronauts can't spend all their time there. They will have to venture into radiation. Detailed radiation maps that take into account the exposure of the sky and the ground and anything else could therefore save lives.