Radiation in space is a formidable challenge. High-energy particles from the Sun, as well as deep-space cosmic rays, move at near-light speeds. Earth's atmosphere and magnetic field provide natural protection, but beyond these barriers, astronauts receive radiation doses equivalent to a full year's exposure on Earth in just a single day. Long-duration missions, such as those to Mars, require alternative protective measures.

Research has shown that water is among the most effective materials for blocking radiation. It has a high density and a large concentration of hydrogen atoms, which slow incoming radiation. However, using free-flowing water in space poses challenges: bulky containers could restrict movement, uneven distribution might leave astronauts unprotected, and punctured water reservoirs could lead to dangerous leaks in electronic-laden environments.

Building on a successful Discovery activity, researchers from Ghent University's Polymer Chemistry and Biomaterials Group (PBM) are now developing superabsorbent polymers (SAPs) as an improved alternative. These polymers can absorb hundreds of times their own weight in liquid, forming hydrogels-materials commonly found in household products such as diapers and contact lenses.

"The beauty of this project is that we are working with a well-known technology," says Lenny Van Daele. "Hydrogels are used in everyday products and in medical applications, such as soft implants to repair tissues and organs."

The ability of hydrogels to hold water makes them ideal candidates for use in radiation shielding, both in space habitats and in extravehicular activity (EVA) suits. Since the water remains locked in the hydrogel structure, it is evenly distributed, ensuring complete protection. Additionally, a puncture would not result in leakage, allowing astronauts time to reach safety.

"This material could also be applied to uncrewed missions, serving as radiation shielding for spacecraft or as a water storage solution once we develop an efficient retrieval method," notes Malgorzata Holynska of the European Space Agency's Materials, Environments and Contamination Control Section.

"The superabsorbent polymer we are working with can be processed using multiple techniques, a rare advantage in polymer science," adds Manon Minsart. "We have chosen 3D printing, which allows us to shape the hydrogel into virtually any form."

Project lead Peter Dubruel emphasizes the importance of innovation in radiation shielding: "There is a continuous search for lightweight protective materials. Our previous research demonstrated that hydrogels are safe for space use. Now, we are refining the manufacturing techniques and scaling up production to bring this technology closer to industrial application."

Related Links
Space Engineering and Technology at ESA
Space Technology News - Applications and Research