Mars is reaching out to us. That is the impression one gets when looking at all the planned and proposed missions to the Red Planet. With so many space agencies currently sending missions there, it's likely that crewed missions are on the way. Both NASA and China have made it clear that they intend to send missions to Mars by the early 2030.
Scientists investigate several means of radiation protection to ensure the health and safety of astronauts. A team from the Blue Marble Space Institute of Science studied how different materials could be used to protect against radiation. Materials brought from Earth and those that can be used on the red planet were included. The In-Situ-Resource-Utilization process is used to meet the needs of the astronauts and the mission.
The leader of the research was Dionysios Gakis, a physics graduate of the University of Patras. Gakis was joined by Dr. Dimitra Atri, a physics professor with the Center for Space Science at New York University Abu Dhabi, and a senior research investigator. The paper describing their findings is being considered for publication.
Due to its thin atmosphere and lack of a planetary magnetic field, the Mars radiation environment is more dangerous than the Earth's. People in developed nations are exposed to an average of 0.62 rads per year, whereas the surface of Mars gets 24.45 rads per year. The radiation comes in many forms, according to Dr. Atri.
“Galactic Cosmic Rays consist of charged particles which are a billion (or more) times more energetic than visible light. They can penetrate through shielding and cause irreparable damage to the human body. Additionally, solar storms can sometimes accelerate charged particles to very high energies (Solar Energetic Particles), which can cause comparable damage. The amount of radiation coming from cosmic rays is highly predictable whereas solar storms are very hard to predict.”
Gakis and Dr. Atri studied the properties of shielding materials that could be taken to Mars. Carbon fiber liquid hydrogen, Mylar, and Mars regolith were among the materials used in these. The materials were assessed using the GEANT4 numerical model and Monte Carlo methods.
He said that they built a model of Mars and measured the Cosmic Energy deposition inside a hypothetical human phantom. The material was supposed to absorb some of the radiation before it reached the astronauts. The materials that let the least amount of energy pass into the astronauts body were the most effective.
Water ice is the best defense against GCRs because it has a predictable response. When combined with aluminum, regolith could be used for additional shielding. It was said by Gakis.
Although aluminum was not as effective as other materials, it can still be helpful in reducing radiation doses. The advantage of being an in-situ material is that it doesn't need to be carried from Earth.
The creation of habitats on the Moon, Mars, and beyond is being assessed by NASA and other space agencies. NASA and the Chinese National Space Agency are planning for crewed missions to Mars in the next 10 years, which will include the creation of habitats on the surface of the red planet. According to Gakis and Dr. Atri, these habitats will likely be made out of lightweight materials.
In the case of aluminum and carbon fiber, they could be produced in-situ using aluminum mined from Mars and carbon taken from its atmosphere. Water ice and regolith, which are locally-harvested, could be used to protect these. It could be a stepping stone to permanent human settlements in space if these habitats are used for long-duration missions.
One of the issues humankind must address in order to successfully accomplish the human exploration of the Red Planet is radiation. We believe that our research is another step in understanding the devastating effects of Cosmic rays in the Martian environment, and planning effective mitigate strategies for future crewed missions to Mars.
ArXiv is further reading.
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