Mars is awash with radiation. Radiation from space is almost unhindered by a magnetic shield or thick atmosphere, so there's no way for radiation to reach Mars' surface. All that radiation can be faced by machines without fear, and they can freely roam the surface.
Humans are not affected by radiation. All that radiation can be deadly for humans.
How will potential human explorers deal with this? They'll need shelter. They'll need shelter, so they will either have to take it with them or build it.
Maybe not. They might use nature's protection as part of their protection.
New data from Mars Science Laboratory (MSL), Curiosity, has revealed how Mars' natural landscape features could provide shelter from radiation. It reveals how Martian buttes protect against high-energy particles coming from space.
The study is entitled "Directionality and Derivation for the Martian Surface Radiation" and was published in Geophysical research Letters. Guo Jingnan, a researcher at the University of Science and Technology of China, is the lead author.
MSL Curiosity landed in 2012 on Mars with a payload that included the Radiation Assessment Detector (RAD) instrument.
RAD is all about preparing for future human missions to Mars. It measures and detects harmful radiation from Mars' Sun and other sources. It can also evaluate the radiation risk to any microbial life on Mars. RAD is approximately the same size as a toaster, and it sits quietly on Curiosity’s top surface.
The Murray Buttes region is one of the areas MSL has studied with RAD. Murray Buttes is located on the lower Mt. Sharp in Gale Crater. Curiosity was here primarily to study geology and especially the sandstone features.
But RAD continued to collect data while they were there. The data showed that there was a decrease in the surface radiation.
MSL Curiosity spent 13 sols near a Murray Buttes butte. While there, it mainly conducted surface science and drilling operations. However, RAD was also available and allowed scientists to access radiation data for 13 days from one location.
The RAD data revealed that radiation doses were reduced by about 5 percent near the butte. A sky visibility map was also created by the research team, which showed that 19% of the sky was blocked when the rover was near the butte.
While this is not a scientific leap of faith when it comes protecting future humans from radiation, it's still important data.
Data can be nuanced. Curiosity couldn't see the sky clearly while driving through Murray Buttes. This was due to terrain features. To compare the data from the 13-sol parking, the team created the panoramic view of sky using averages over several months.
These averages may be approximated, but they will have to do.
Sky map showing the effects of radiation exposure on the butte. (Jingnan et al., GRL, 2021)
These averages and approximations are represented by the red dotted line in the above image.
RAD also discovered another thing. Radiation that strikes people or other objects on Mars' surface is a result of radiation from space. The majority of radiation that strikes a person or piece of equipment is directly from the skies.
Some radiation is albedo radiation. This means it strikes objects below the surface. What did RAD discover about this?
The surface features that provide protection against direct radiation can also increase the reflected radiation. RAD found that buttes could increase secondary, reflected radiation. This is one of the many complexities in understanding Mars radiation.
The radiation dose to Mars' surface is not constant, but it fluctuates. It can be affected by heliospheric and angle changes, which can also affect the radiation dose on Mars. An angle that is steeper means radiation must travel through more atmosphere to change the surface exposure.
The distance Mars orbits the Sun changes, which can also impact surface radiation. Higher altitudes will receive less radiation than lower altitudes. Radiation is not a single phenomenon. There are alpha particles, protons, ions from various elements, neutrons and gamma radiation.
The study provides a better picture of Martian radiation environments. A lot of effort has been put into in-situ resource usage on Mars. Exploring Mars requires shelter. If there is an advantage to using terrain features as protection, those features can be incorporated into a mission profile.
There is much talk of putting bases in lava tubes. These would protect people from the Martian regolith, which could be meters thick. However, astronauts cannot spend their entire time in lava tubes. They will have to venture outside into the radiation.
Layers upon layers of contingencies will be required for any mission to Mars that involves humans. It's vital that astronauts are kept as radiation-free as possible in the event of an emergency.
The entire mission will aim to limit annual radiation exposure. It is not difficult to imagine the planetary explorers using every radiation shelter available to them as they attempt to deal with equipment failures or other mishaps.
Radiation maps that include terrain and sky exposure could save lives.
Universe Today originally published this article. You can read the original article.
