[Science Column] Development of a "Nano Shield" Blocking Cosmic Radiation

KIST and KAIST Develop Boron Nitride Nanotube Shielding Film
Protecting Lunar and Martian Bases from Radiation Threats
Mission Duration Expected to Double

A team of Korean researchers has developed a high-performance "nano shield" that blocks cosmic radiation using boron nitride nanotubes (BNNTs). This technology is gaining attention as a key advancement to enhance the safety of human activities in space, including the construction of lunar and Martian bases and long-term crewed missions.

The team led by Dr. Jang Saekyu at the Functional Composite Materials Research Center of the Korea Institute of Science and Technology (KIST), together with Professor Choi Siyoung's group from the Department of Biological and Chemical Engineering at the Korea Advanced Institute of Science and Technology (KAIST), announced on November 5 that they have developed a "boron nitride nanotube radiation shielding film" by densely aligning BNNTs. This film features high strength, excellent thermal conductivity, and outstanding neutron shielding capabilities.

Comparison of the performance between the existing radiation shielding film and the newly developed shielding film by the research team. Provided by the research team.

BNNTs are ultra-fine tube-shaped structures with a diameter of about 5 nanometers (nm), which is 1/20,000 the thickness of a human hair. They are lightweight, strong, and have exceptional neutron absorption capacity. However, due to previous limitations in processing technology, BNNTs could only be produced in thin, brittle sheet forms.

The research team succeeded in stably dispersing BNNTs in water using a surfactant called dodecylbenzenesulfonic acid (DBSA), then manufactured them in a high-concentration liquid crystal state to align the fibers in a single direction. The resulting BNNT film demonstrated a density three times higher and neutron shielding performance 3.7 times better than existing materials.

Joint simulations with the National Aeronautics and Space Administration (NASA) showed that, at the same mass thickness, the film exhibited about 15% higher radiation blocking efficiency compared to aluminum, with particularly superior secondary neutron shielding performance. When applied at an appropriate thickness, this film is expected to provide lunar astronauts with a radiation safety environment equivalent to that of the International Space Station (ISS), potentially doubling the duration of their missions.

Dr. Jang Saekyu of KIST stated, "Maximizing the alignment and density of BNNTs and demonstrating their practical shielding effect represents a significant technological breakthrough," adding, "This is a versatile, next-generation material that can be utilized not only in space, but also in aviation, defense, and nuclear power sectors."

This research was supported by the Ministry of Science and ICT, the Ministry of Trade, Industry and Energy, and the Defense Acquisition Program Administration. The results were published in the latest issue of the international journal Advanced Functional Materials (IF 19.0) under the title, "High-Density Boron Nitride Nanotube Composites via Surfactant-Stabilized Lyotropic Liquid Crystals for Enhanced Space Radiation Shielding."