Today I’ve been watching a documentary mini-series all about humanity’s first mission to Mars, called Mars Rising. It’s narrated by William Shatner, and has decent production values and explores a lot of different facets in six 1-hour episodes.

Shielding humans from radiation in space is one of our greatest challenges, and long-term habitation off-world will depend on the development of reliable systems capable of reducing exposure to radiation. It’s interesting to hear astronauts talk about experiencing cosmic radiation showers in LEO. They saw tiny contrails in the air, as in a cloud chamber. When they closed their eyes to sleep, their retinas actually saw the tiny flashes of light as ionizing radiation would collide with the atoms inside their eyeballs.

Current aluminum structures not only fail to protect against radiation, the metal actually reacts with cosmic radiation to spit out even worse particles and rays into the crew cabin. Hydrogen atoms are a fantastic barrier, allowing already-valuable water to serve as shielding. Polyethylene is another material already being utilized on the shuttle and ISS. Long chains of carbon atoms covered in hydrogen form the molecular structure of the material. Future craft may be made from carbon composites incorporating the protective properties of polyethylene, providing a material that is lighter, stronger and more effective than aluminum.