An Italian and German team has made a major research breakthrough by demonstrating that permanent magnets could play a central role in protecting astronauts from radiation when traveling in space. Radiological events such as galactic cosmic rays and solar flares are among the most common hazards addressed by researchers and are an important consideration for current and future deep space missions. The research team packed 1,482 permanent neodymium-iron-boron magnets, each measuring 1.6 square inches, into an 11-square-foot array that ended up weighing 661 pounds. The array deflected about 20% of solar particles in the energy range of 0.1 to 10 megaelectronvolts. Even though the experiment showed that this solution could successfully deflect low-energy particles, high-energy particles were still able to penetrate the magnet’s shield. Although the concept does not deflect high-energy radiation, it could be part of a hybrid protection system intended to protect astronauts.
This is not the first time that researchers have explored the possibility of using magnets as a defense against radiation. Superconducting magnets that form a 1-tesla magnetic field around spacecraft have also been studied, but present practical problems, requiring cryogenic cooling and constant, fail-safe power sources to maintain protection. Providing these essential elements on a spacecraft would be very difficult due to weight limitations and the likelihood of power outages.
The problem of protecting astronauts from radiation is more relevant than ever as humanity moves closer to exploring Mars, going further into deep space than ever before. Spaceflight entities around the world are currently not doing enough to integrate radiation protection into spacecraft hulls, and research like this will break the feasibility limits that have existed since the Apollo era.
How do magnets deflect radiation?
Radiation sources like cosmic rays are primarily made up of protons that travel at high speeds. The force at play with the permanent magnets used in this test is known as the Lorentz force. It is a force that exists between a magnetic field and a moving charge. When a charged particle moves in the magnetic field, the Lorentz force acts on the particle in a direction perpendicular to that of the magnetic field and the path of the particle. This changes the path of the charged particle, moving it away from the subject it aims to protect.
If it’s a good solution in a controlled test, teams will need to figure out how to deploy the technology on a spacecraft. Cosmic rays do not come from a single direction in deep space, and so magnets would have to cover all or most of a spacecraft’s hull. The directionality of the deflections should also be considered, as well as the effect of protons hitting the magnets, which could cause secondary radiation exposure.
Why radiation is such a problem during deep space travel
When leaving Earth for a deep space mission, astronauts must pass through the high-radiation zone called the Van Allen belts, which are two rings of high-energy particles trapped by Earth’s magnetic field. Astronauts would also be sensitive to other sources of radiation such as galactic cosmic rays and solar flares. Additionally, the Moon’s surface is highly radioactive, with levels approximately two to three times higher than those observed on the ISS. To put this into perspective, the astronauts who participated in the Apollo 14 mission were exposed to approximately 1.14 rads of radiation during their mission, approximately double the dose received during an abdominal CT scan. This level of exposure isn’t considered that dangerous, but that’s not the problem.
The problem is that few missions have been flown into deep space with astronauts on board, and even though the radiation levels encountered were within safe limits, these missions did not see significant solar particle events. As humans explore deeper into space, much is still unknown about radiation exposure, and given the damage radiation can do to the body, protecting astronauts remains at the top of NASA’s priority list.
In 1972, between the Apollo 16 and 17 missions, a solar flare was documented, which would later be considered a near miss for NASA, and if the astronauts had been in deep space or on the Moon at that time, they would have suffered a fatal dose of radiation. The astronauts on the Artemis II mission had only one form of protection in the event of a solar flare while in deep space: it involved building a fort around themselves of goods and supplies, and huddling inside until the danger had passed.
