Looking at this Business Insider article, one of the biggest hurdles of getting humans to Mars is how to reduce the amount of radiation that they are subjected to.
Now we do have the Vantablack paint that is able to absorb some 99.965% of visible light. The Wikipedia article on it describes how it works as this:
When light strikes Vantablack, instead of bouncing off, it becomes trapped and is continually deflected amongst the tubes, eventually becoming absorbed and dissipating into heat.
Would it be physically possible to create a similar paint (or a relatively thin structural layer) that traps cosmic radiation instead?