For Radiation Protection, Just Add Water

Space radiation is one of the main challenges for manned expeditions to Mars, because it poses a significant risk to the astronauts’ health. Indeed, a six-month journey to Mars would incur 60% of the total radiation dose an astronaut can be exposed to in their entire career. Providing effective protection from space radiation through careful material selection for spacesuits, space shelters and spacecrafts is therefore essential to advance space exploration. While materials such as aluminum and poly(ethylene) provide good protection, water is also a very promising candidate, despite being difficult to handle. Hydrogels can provide a solution to this challenge. They efficiently capture water and enable incorporation into constructs to provide protection from space radiation. As they elegantly combine equal water distribution and strong water binding, water loss upon puncture – a risk for regular water reservoirs – is no longer a concern. Moreover, they are much more conformable than other rigid materials. Herein, we have developed new hydrogel materials based on photo-crosslinkable hydrophilic polymer building blocks that can be synthesized in a straightforward fashion on a large scale (i.e. kg scale) starting from readily available chemicals. By varying the polymer properties, we can also tune the hydrogel properties, including the swelling capacity and the mechanical properties. Indeed, the most promising hydrogel system can take up water 14 times its own weight while maintaining a gel fraction of over 97% and an E-modulus of 81 kPa, indicating sufficient mechanical strength and integrity. The obtained materials have consecutively been processed using state-of-the-art processing techniques to enable the production of three-dimensional hydrogel structures that can then be incorporated into fabrics and constructs to be used for space radiation protection, such as spacesuits, space shelters and spacecrafts.