Re: Do plastics in spacecraft or spacesuits show tracks from high energy events

John,

Maybe you are referring to studies of particle tracks found in the Lexan helmets worn by Apollo astronauts, like the ones pictured in this article.

You are correct that these tracks are due to high energy particles, also known as cosmic rays. Although a "cosmic ray" can be one of many different particles, the tracks you see here are from heavy nuclei colliding with the plastic. In some cases the cosmic ray passes completely through the plastic, and in others the particle is stopped inside the material.

Just to clarify things, the damage you see in the pictures is not actually caused by the particle track. A heavy nucleus passing through the plastic leaves no visible track, but weakens the molecular bonds in the material. So to detect these tracks, a caustic solution is used to etch away the damaged material, leaving behind the pits that show where the cosmic rays were.

Among other studies, helmets worn by astronauts during different Apollo missions have been analyzed this way to study changes in the solar and galactic cosmic radiation backgrounds, and to predict the radiation exposure to astronauts on future space missions, such as going to Mars.

Hope this helps!