A recent study shows that an experimental panel of 1,482 neodymium-iron-boron magnets can deflect roughly 20% of solar protons. This 661-pound array offers a passive, power-free method to protect astronauts from radiation during long-duration missions to Mars.
The 661-pound panel of 1,482 neodymium magnets
The experimental array used to test radiation deflection consisted of 1,482 neodymium-iron-boron permanent magnets. As the report notes, each magnet in the set has a surface area of 1.6 square inches.
This 11-square-foot panel, weighing 661 pounds, successfully deflected approximately 20% of solar protons within the 0.1 to 10 megaelectronvolts energy range. The experiment demonstrated the core principle of using the Lorentz force to alter the trajectory of charged particles through a passive magnetic field.
The choice between 1-tesla superconducting magnets and passive arrays
Spacecraft designers must weigh the benefits of high-strength superconducting magnets against the simplicity of permanent magnet arrays. While superconducting systems can generate much stronger fields—around one tesla—they require continuous cryogenic cooling and a fail-safe power supply.
According to the study, the logistical burden of providing cooling and constant power is a major drawback for missions where mass and energy are at a premium. A permanent magnet solution offers a compelling alternative because it requires no power and minimal maintenance, even if its deflection capabilities are more modest.
The unresolved risks of secondary radiation and high-energy rays
A significant challenge for magnetic shielding is the potential for high-energy cosmic rays to penetrate the field entirely. The research highlights that while lower-energy particles are deflected , high-energy cosmic rays and solar particles can still pass through the magnetic field.
There is also the danger of secondary radiation, such as neutrons or gamma rays, being generated when high-energy protons strike the magnet material itself. This could inadvertently increase the radiation dose inside the spacecraft.
Several engineering questions remain unanswered following the laboratory success. researchers must still determine how to manage the directionality of deflected particles to avoid hitting sensitive equipment, and how to scale the system to encompass a full spacecraft hull without adding prohibitive mass.
Lessons from the 1972 solar eruption and Apollo 14
Historical spaceflight data highlights the extreme danger of solar particle events that can deliver fatal doses in hours. For example, the Apollo 14 crew received an estimated 1.14 rads during their lunar mission,a dose roughly double that of an abdominal CT scan.
The urgency for better shielding is underscored by the massive solar eruption that occurred in 1972 between the Apollo 16 and 17 missions. Had astronauts been in transit during that event, the radiation levels could have been lethal.
Current plans for the Artemis II lunar flyby rely on a rudimentary storm shelter—a fortified area within the craft—rather than an integrated magnetic shield. however, a systematic, engineered solution like a magnet array could provide much higher safety margins for the long transit times required for Mars exploration.
Comments 0