Mars is reaching out to us. At least, that is the image one gets when looking at all of the planned and proposed trips to Mars during the next decade. With so many space organizations now launching missions to define their habitat, atmosphere, and geological history, crewed missions appear to be just around the horizon. Indeed, both NASA and China have stated that they want to send missions to Mars by the early 2030s, culminating in the construction of surface homes. Scientists are studying several methods of radiation shielding to safeguard astronaut health and safety, both in transit and on the surface of Mars. A team from the Blue Marble Space Institute of Science (BMSIS) has investigated how various materials may be utilized to create radiation-protective structures. Materials transported from Earth, as well as those gathered directly from the Martian environment, were included. This is consistent with the ISRU method, in which local resources are used to suit the demands of the astronaut crews and the mission.
Dionysios Gakis, a visiting scholar at BMSIS and a physics graduate of the University of Patras in Greece, conducted the research. Dr. Dimitra Atri, a senior research investigator at BMISIS, a physics professor at New York University Abu Dhabi’s Center for Space Science, and Gakis’ academic advisor, accompanied him. Acta Astronautica is considering publishing the manuscript that outlines their findings (“Modeling the efficiency of radiation shielding materials for astronaut safety on Mars”).
Because of its thin atmosphere and absence of a planetary magnetic field, Mars’ radiation environment is substantially more harmful than Earth’s. People in wealthy countries are exposed to 0.62 rads per year on average, but the surface of Mars receives around 24.45 rads per year—and considerably more when solar events occur.
“Galactic cosmic rays consist of charged particles that are a billion (or more) times more energetic than visible light. They can penetrate through shielding and cause irreversible 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,” Dr. Atri told Universe Today in an email.
Gakis and Dr. Atri looked into the qualities of several shielding materials that may be delivered to Mars or gathered in situ for their research. Aluminum, polyethylene, cyclohexane, polymethyl methacrylate, Mylar, and Kevlar were among the materials used, along with water, carbon fiber liquid hydrogen, and Martian regolith. According to Gakis, they evaluated each of these materials using the GEANT4 numerical model, which is a software suite that uses statistical Monte Carlo techniques to simulate particle passage through matter.
He explained, “We developed a computational model of Mars and analyzed the cosmic energy deposition within a hypothetical human phantom, simulating an astronaut.” “Before the radiation reached the astronaut, a barrier of material was placed to absorb some of it. In terms of radiation protection, the materials that allowed the least amount of energy to travel through the astronaut’s body proved to be the most effective.”
Their findings showed that hydrogen-rich materials (such as water ice) respond predictably to cosmic rays and are hence the best barrier against them. They also discovered that regolith has a medium response and, as a result, might be utilized for extra shielding, especially when paired with aluminum.
Gakis stated: “Although aluminum was not proven to be as efficient as other materials in decreasing radiation doses, it can still be useful, and we recommend mixing it with other materials. The behavior of Martian regolith is comparable, and it has the benefit of being an in-situ substance that does not need us to transport it from Earth.”
NASA and other space organizations are evaluating a variety of designs, materials, and technologies that may be used to build homes on the moon, Mars, and beyond. NASA and the Chinese National Space Agency (CNSA) are preparing crewed trips to Mars in the following decade, with flights launching every 26 months (beginning in 2033) and culminating with the construction of surface homes. According to Gakis and Dr. Atri’s research, these homes will most likely have an inner construction made of lightweight materials that can be carried cheaply from Earth.
Metal and carbon fiber, for example, may be made in-situ with aluminum extracted from Martian rock and carbon gathered from the planet’s atmosphere. Locally obtained water ice and regolith might then be used to form a protective superstructure, which robots would 3D print. Long-duration expeditions far beyond Earth will be possible with such homes, which might potentially serve as a stepping stone to permanent human colonies in space.
“One of the numerous concerns that humanity must overcome in order to effectively complete the human [exploration of] the red planet is radiation,” Gakis summarized. “We think our findings contribute to a better understanding of the harmful impacts of cosmic rays on the Martian environment and the development of appropriate mitigation techniques for future crewed missions to Mars.”
