There’s at least a small handful of teams—NASA, the Chinese Space Agency, SpaceX, Mars One, and others—looking to put people on Mars in the next few decades. Other than the trouble involved in getting people to the red planet, landing them on the surface, giving them enough food and water to survive and stopping them from going crazy with isolation, there’s another big hurdle to jump: radiation. And not just measly, harmless radiation like from your cell phone. Space is full of galactic cosmic rays, incredibly high energy particles–like lead that’s moving near the speed of light. Galactic cosmic rays can blast through your DNA, shredding the bonds and increasing your risk of cancer.
Stopping all this radiation is one of the challenges for anyone looking to send people far from Earth, and new research is pointing us in an unusual direction on how to do it: plastic spaceships.
Aluminum, being both strong and light, is the material of choice for spaceship building. But aluminum isn’t so hot at blocking radiation. Plastic, on the other hand, seems to be way better.
This isn’t an entirely new idea. Back in 2004 NASA wrote about how plastic could be used to protect the explorers of the solar system, speaking with NASA scientist Frank Cucinotta, who works on the Space Radiation Health Project:
Plastics are rich in hydrogen–an element that does a good job absorbing cosmic rays,” explains Cucinotta. For instance, polyethylene, the same material garbage bags are made of, absorbs 20% more cosmic rays than aluminum. A form of reinforced polyethylene developed at the Marshall Space Flight Center is 10 times stronger than aluminum, and lighter, too. This could become a material of choice for spaceship building, if it can be made cheaply enough. “Even if we don’t build the whole spacecraft from plastic,” notes Cucinotta, “we could still use it to shield key areas like crew quarters.” Indeed, this is already done onboard the ISS.
While plastic was already thought to be theoretically better than aluminum at protecting astronauts based on laboratory tests no one had ever tested it using a craft that is fully exposed to cosmic rays. That’s where the new research comes in, says Cary Zeitlin, the leader of the study:
This is the first study using observations from space to confirm what has been thought for some time—that plastics and other lightweight materials are pound-for-pound more effective for shielding against cosmic radiation than aluminum. Shielding can’t entirely solve the radiation exposure problem in deep space, but there are clear differences in effectiveness of different materials.
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