Astronauts on Mars can survive killer radiation if they dig deep trenches, study finds

Scientists studying the planet Mars have suggested that digging deep into the red planet's surface can protect astronauts from harmful radiation. Not only that, but these structures dug on the Martian surface would also provide materials that can be used to build habitats. The scientists published their findings in the Journal of Geophysical Research: Planets, claiming that this would help avoid serious health issues among the first settlers.

Blocking GCR

When the scientists say radiation, they primarily mean the galactic cosmic ray (GCR) particles that bombard the red planet throughout the day. According to Space.com, the U.S. National Oceanic and Atmospheric Administration (NOAA) defines GCRs as particles that are highly energetic and "consist of essentially every element" discovered to date. These particles are known to originate from outside of our solar system. Scientists say that they are emitted from bursting stars and also from bouncing off the Earth's magnetosphere, the bubble of a magnetic field that surrounds the Earth.  

Scarily enough, exposure to such particles could cause serious health issues in humans, with cancers, cataracts and damage to the central nervous system being the most prevalent. And since Mars has an extremely thin atmosphere and no magnetosphere like the Earth, the GCR particles easily reach the surface.

Using the Martian topography as an advantage

"It has long been argued that astronauts could make use of natural geological structures, such as cave skylights or lava tubes as radiation shelters on Mars. Our study may serve for mitigating radiation risks when designing future Martian habitats using natural surface material as shielding protection", the researchers wrote as per Space.com.

The experts used the Atmospheric Radiation Interaction Simulator (AtRIS) and the Curiosity rover's radiation data to determine the penetration capacity of the GCR particles into the Martian surface. They found that the radiation dose peaked at around 12 inches (30 centimeters) into the surface and concluded that a regolith shield measuring between 3.3 to 5.5 feet will be required to ensure habitability. 

Notably, Mars has the biggest volcano in the solar system- Olympus Mons- which stands 26 kilometers tall but also houses the crater Hellas Planitia which is about seven kilometres deep. However, what's important is that the thickness of the Martian atmosphere varies in different areas and thus the amount of GCR particles reaching the surface also varies.